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  Current Issue
 
2022 Vol.42 Issue.7,Published 2022-07-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Microbiology
Environmental Ecology
Environmental Toxicology and Health
Biodiversity
Carbon Emission Control
Air Pollution Control
2977 Investigating the temporal and spatial variabilities of total ozone over China for the past 50 years
XIE Jing-han, LI Sa, XIAO Zhong-yong
Based on the Multi-Sensor Reanalysis version 2data, which was validated by the data from 6ground-based observation stations belonging to the World Ozone and Ultraviolet Radiation Data Centre, this study analyzed the temporal and spatial variabilities of total ozone over China for the period 1971~2020. It was found that the total ozone over China showed a slight downward trend in the past 50years. The annual mean total ozone reached a maximum value of (347.5 ±53.8) DU in 1978 and a minimum one of (291.9 ±29.5) DU in 1993. In the three sub-periods, 1971~1978, 1978~1993, and 1993~2020, the annual mean total ozone over China completely increased, decreased, and increased, respectively. The seasonal variability of the monthly mean total ozone presented a sinusoidal wave with a maximum value of about 338DU in March and a minimum value of about 285DU in October. The spatial distribution of the annual mean total ozone over China in the past 50years showed a latitudinal pattern by decreasing gradually from northeast areas to southwest areas. Moreover, the values could be greater than 360DU in the northeast China with latitudes over 40°N. The spatial distribution of monthly mean total ozone also showed a latitudinal pattern. In addition, the temporal and spatial variation coefficients showed similar seasonal variability, with the minimum value in summer, followed by the values in autumn, spring, and winter. Namely, the variability of total ozone and its spatial difference was minimum in summer. Finally, the trend of total ozone varied with periods and areas in the past 50years. During the period 1971~1978, the increase value and rate of annual mean total ozone showed a latitudinal pattern by decreasing gradually from north areas to south areas. In the areas with relatively high annual mean total ozone, such as the north China with latitude over 40°N, the maximum increase value was 56DU, around 16%. Yet, in the areas with relatively low annual mean total ozone, such as the south China with latitude below 30°N, the minimum increase value was 12DU, around 5%. During the period 1978~1993, the decreased value and rate of annual mean total ozone also showed a latitudinal pattern. In the areas with relatively high annual mean total ozone, such as the north China with latitudes over 40°N, the maximum decrease value was 93DU, around 22%. Yet, in the areas with relatively low annual mean total ozone, such as the south China with latitude below 30°N, the minimum decrease value was 11DU, around 4%. During the period 1993~2020, the maximum increase value (18DU, about 6%) was found in the northwest areas. In contrast, the minimum increase value (4DU, about 1%) was found in the southeast areas.
2022 Vol. 42 (7): 2977-2987 [Abstract] ( 241 ) [HTML 1KB] [ PDF 2663KB] ( 804 )
2988 Analysis on the potential source and transmission channel of particulate matter in Lüliang City, Fenwei Plain
GAO Xing-ai, PEI Kun-ning, WANG Shu-min, YAN Shi-ming, WANG Yan, JIANG Yun-sheng
Based on the particulate matter concentration and surface meteorological observation data of Lüliang city in Fenwei Plain from 2017 to 2019, this paper used backward trajectory cluster analysis and potential source contribution function (PSCF) methods to study the characteristics of PM10 and PM2.5 pollution and their potential source areas in winter in Lüliang city. Combining trajectory density analysis (TDA) and trajectory dwell time analysis (RTA) to supplement the classification of polluted transmission channels obtained by trajectory clustering analysis, and analyzed the transport characteristics of different transmission channels. This study found that the annual average concentration of particulate matter in Lüliang City decreased year by year from 2017 to 2019. Among them, PM10 decreased by 28μg/m3, PM2.5 decreased by 17μg/m3, and the decline was the largest in winter. The statistical analysis of the three-year winter wind direction, wind speed and concentration showed that the concentration of particulate matter in Lüliang was most significantly affected by the northeast and southwest winds because of the local topography of the Sanchuan River valley. The potential source area of PM10 pollution in Lüliang was mainly located in the southwest, and the potential source areas of PM2.5 pollution were mainly located in the southwest, east and southeast. The particulate pollution transmission channels can be summarized as: northwest, southwest and east (east and southeast) channels. The airflow in the northwest channel moved fast, passing through Xinjiang, Inner Mongolia, Gansu, and northern Shaanxi; The airflow in the southwest channel moved slowly, mainly passing through heavily polluted areas such as the Weihe Plain in central and southern Shaanxi. The airflow in the east channel moved slowly, it first traveled south along the eastern foot of the Taihang Mountains, and turned into Shanxi when passing through the valleys(Taihangxing, Jingxing, etc.) of the Taihang Mountains. When PM10 pollution occurred, the northwest channel contributed the most, and the eastern channel contributed the least, and the majority of these two channels was lightly polluted, accounting for about 90%. When PM2.5 pollution occurred, the proportion of light pollution under the three types of channels was lower than that of PM10. The proportion of moderate pollution and above under the southwest and east channels were about 50%, the areas passed by the southwest and east channels were exactly the potential source locations calculated by PSCF, which also showed that the southwest and easterly airflows were likely to transport pollutants to Lvliang. Finally, the three transportation channels were verified by the wind field simulation results of the WRF model, which shows that the transportation channel results obtained in this study are valid, and the complex terrain and variable airflow are an important factor in the transmission channel. The wind field simulation of the WRF model intuitively explains the three types of pollution transmission channels, and the complex terrain is an important factor in the formation of pollution transmission channels. The pollution transport channels in the northwest and southwest are mainly affected by the Lüliang Mountains, and the eastward pollution transport channel is mainly affected by the Taihang Mountains and its Henggu.
2022 Vol. 42 (7): 2988-2999 [Abstract] ( 153 ) [HTML 1KB] [ PDF 4771KB] ( 567 )
3000 Filling the missing data of AOD using the situ PM2.5 monitoring measurements in the Beijing-Tianjin-Hebei region
SONG Chun-jie, WEI Qiang, FAN Li-hang, WANG Wei, HAN Fang, LI Wei-miao, LI Fu-xing, CHENG He-xi
A spatiotemporal linear mixed effect model (STLME) and a spatiotemporal nested linear mixed effect model (STNLME) were presented using the PM2.5 measurements of 318 ground monitoring stations in Beijing-Tianjin-Hebei (BTH) in 2020 to fill the missing data of AOD. The results indicated that the STLME and STNLME models in the days with AOD-PM2.5 matchups showed similar performance with the cross-validation (CV) R2 valued at 0.868 and 0.874, and the root mean square error (RMSE) valued at 0.112 and 0.109, respectively. However, the STNLME model with the CV R2 valued at 0.63 outperforms STLME with the CV R2 of 0.26 in the days without PM2.5-AOD matchups. After models filling, the spatial valid value ratio of AOD data in the grid where the monitoring stations are located was increased from 44.35% to 99.35%, and the temporal valid value ratio was increased from 87.94% to 100%. Meanwhile, the annual mean AOD value of each station had increased significantly, and the missing AOD were filled under the condition of high PM2.5 level, which could reduce the biases of exposure assessment in air pollution and health studies.
2022 Vol. 42 (7): 3000-3012 [Abstract] ( 149 ) [HTML 1KB] [ PDF 2106KB] ( 426 )
3013 Influence of a boundary layer low-level jet on pollutant diffusion in Shouxian, Anhui Province in winter 2016
JING Cui-wen, WANG Cheng-gang, FENG Yan
Based on the observation data and simulation data in Shouxian area of Anhui Province from December 16 to 17, 2016, the effect of a nocturnal boundary layer low-level jet on PM2.5 diffusion has been analyzed. In this process, the low-level jet has a wide distribution range and high intensity, the maximum wind speed can reach 10~12m/s, the wind direction difference between high and low layers can reach 90℃ during the development of the low-level jet. In the process of the low-level jet development, the jet axis is basically below 200m, and the minimum wind speed height of the low-level jet appears between 400~800m. The analysis shows that there are obvious differences in the impact of the low-level jet on pollutant diffusion at different heights. From ground to the low-level jet axis, PM2.5 overall decrease. The emergence of the low-level jet flow significantly enhances the turbulent mixing. Under the action of turbulence, the pollutants are mixed upward, making the layer PM2.5 significant reduction. The peak value of net mass flux can reach -103×10-3μg/(m2·s).The horizontal transportation of the low-level jet stream can bring cleaner air mass upwind, and also reduce PM2.5 concentration in this layer. However, compared with turbulence, its effect is small, and the net mass flux is only -2.9×10-3μg/(m2·s). When the low-level jet exists, the downward vertical wind speed will be strengthened. Under the action of vertical transportation, the pollutants in the upper layer will be transported downward, increasing the PM2.5 concentration in this layer, the net mass flux is about 11×10-3μg/(m2·s). Between the low-level jet axis and wind direction transition height, PM2.5 overall increase. This is because the turbulence transports high concentration pollutants in the low layer to this layer, making PM2.5 concentration increase. The net mass flux is about 23.9×10-3μg/(m2·s). Horizontal transportation makes this layer PM2.5 concentration increased slightly, and the net mass flux was about 2.3×10-3μg/(m2·s).The vertical transportation brings clean air mass at high altitude and reduces PM2.5 concentration, the net mass flux is about -6.6×10-3μg/(m2·s). Between wind direction transition height and LLJ minimum wind speed height, PM2.5 overall increase. Turbulence is still dominant, and the net mass flux is about 17.8×10-3μg/(m2·s).The vertical transport has a slight contribution, and the net mass flux is about 1.4×10-3μg/(m2·s). The horizontal transport plays a reducing role, and the net mass flux is about -3.7×10-3μg/(m2·s).
2022 Vol. 42 (7): 3013-3022 [Abstract] ( 133 ) [HTML 1KB] [ PDF 2013KB] ( 375 )
3023 Characteristics and sources of ozone and its precursors aroundthe Wuhan Military Games
MA Jing, YAN Ying-ying, KONG Shao-fei, SONG Ai-li, CHEN Nan, ZHU Bo, QUAN Ji-hong, QI Shi-hua
The hourly data of ozone, NOx (= NO + NO2) and VOCs (102species) during October~November 2019 provided by Hubei Superstationwere used to analyze the variation characteristics of ozone pollutionduring the Wuhan Military Games (WMG). The photochemical regime of ozone was simulated based on DSMACC box model. The source apportionment of VOCs was conducted by PMF model, and the ozone formation potential of different VOCs sourcewas estimated. The results showed that the maximum daily 8-hour average ozone concentration (maximum MDA8:219.51μg/m3) exceeded the national level II standard before the military games. The MDA8 values (135.11μg/m3 on average) decreased significantly during the military games, and the concentrations (140.98μg/m3) rise after the WMG. The difference of ozone before and during the military games was mainly affected by meteorological conditions, and the increase of ozone after the WMG was mainly due to the significant increase of precursor emissions. The EKMA curve indicates that the photochemical formation of ozone was controlled by a VOC-limited regime during the study period. The VOCssources that contribute greatly to ozone formation before the military games were combustion, petrochemical industry and motor vehicles, accounting for 23.0%, 22.8% and 22.5%, respectively. The main sources of VOCs during the military games were motor vehicles (38.4%) and combustion (25.5%). While petrochemical industry (32.6%) and fuel volatilization (25.7%)were the main sources after the WMG. The results showed that the prevention strategies of the military games had a significant effect on the emission reduction of petrochemical industry, but the emission mitigation of motor vehicles and combustion was not significant. Wuhan should pay more attention to the control of combustion, fuel volatilization and motor vehicle emissions.
2022 Vol. 42 (7): 3023-3032 [Abstract] ( 174 ) [HTML 1KB] [ PDF 1191KB] ( 399 )
3033 Determination of crustal element iron light absorption contribution and effects on black carbon light absorption enhancement estimation: a case study in Wuhan
TAN Jian, XIA Rui, WU Dui, KONG Shao-fei, CHEN Nan, CHENG Chun-lei, DENG Tao, TAO Li-ping, ZHANG Xue, WU Bo-xi, WU Liang-bin, WANG Qing, WU Cheng
The traditional method uses empirical absorption Ångström exponent to estimate the light absorption of crustal elements or brown carbon, and this method can only handle the two components scenario (blackcarbon/brown carbon or blackcarbon/crustal elements), leading to substantial uncertainties. This study introduces a new method that uses the Fe as the crustal element tracer. Using measurement data in Wuhan (February, March, August, and September 2021) by applying the minimum R-squared method (MRS), the crustal elements light absorption contribution can be obtained. After subtracting the crustal elements light absorption, absorption enhancement factor (Eabs) can be obtained. The results showed that the average crustal elements absorption contribution at 370nm during the observation period was 12.3%, with a monthly average ranging from 5.7% to 15.5%. Meanwhile, AAE exhibited a positive dependence on the concentration of Fe. These collective clues indicate that the crustal elements absorption contribution cannot be ignored. Crustal elements light absorption demonstrated a considerable seasonality, which was low in winter and high in spring. There are deviations in the calculated Eabs before and after the separation of crustal elements light absorption, which is influenced by the correlation between blackcarbon and iron. During the observation period, after deducting the light absorption of crustal elements, the average Eabs was 1.43±0.53, and Eabs was high in spring and summer, and low in autumn and winter. HighEabs in spring was associated with a higher degree of BC aging. The analysis found that Eabs demonstrated a positive dependence on the content of inorganic salts and organic matters, which proves the influence of these coating materials on the enhancement of light absorption.
2022 Vol. 42 (7): 3033-3045 [Abstract] ( 118 ) [HTML 1KB] [ PDF 1519KB] ( 363 )
3046 Measurement of emission fluxes of total non-methane alkanes from refineries using solar occultation flux remote sensing technique
LI Ling-bo, GONG Chao, CHENG Meng-ting, LI Long, LIU Xin-yu
The emission fluxes (kg/h) and distributions of total non-methane alkanes from seven major refineries (in which six refineries were processing crude oil more than ten million tons per year) in China were quantified during May 2014 and December 2015 and in October 2021 using the Solar Occultation Flux (SOF) method. At each refinery site, 18~73measurement transects were performed during three to eight individual measurement days. In total, 328measurements of total non-methane alkane emission flux were performed for the seven refineries. Total VOC emissions were estimated from the measured total non-methane alkane emissions based on the average mass fraction of non-methane alkanes in total volatile organic compounds (VOC) measured in VOC emission plumes of several refineries in China. Total non-methane alkanes and VOC emission factors were calculated by scaling measured emissions of total non-methane alkanes and estimated emissions of VOCs with crude oil processing rates during the measurement period. The monitoring results indicate that the measured total non-methane alkanes emission factors ranged from 0.016% to 0.11% for the seven studied refineries and were 0.081% on average. The estimated VOC emission factors for the seven studied refineries ranged from 0.020% to 0.14%, with an average value of 0.10% during 2014 and 2015. Fugitive emissions accounted for more than 70% of total non-methane alkane emissions from refineries, and light oil tanks contributed more than 50% of fugitive non-methane alkane emissions. The results were compared to SOF measurements at six refineries in the South Coast Air Quality Management District (SCAQMD) in 2015, and the lowest level of total non-methane alkane emission factors in the seven refineries in China measured during 2014 and 2015 was the same as that for all six refineries in SCAQMD. However, the average level of total non-methane alkane emission factors of the seven refineries in China was 3.9times higher than that of the six refineries in SCAQMD, and there was a higher variability in total non-methane alkane emission factors among the seven refineries in China. The emission flux and emission factor of non-methane alkanes monitored in a major Chinese refinery in 2021 showed a reduction by 72.4% and 74.2% respectively compared with 2015. SOF could be developed as the best available technique for monitoring and quantifying fugitive and diffuse VOC emissions from petroleum and petrochemical industrial sites, and for revising VOC emission inventories. This study has provided a baseline of measured emissions of total non-methane alkanes and VOCs from typical refineries in the initial stage of VOC emissions control actions implemented in China in 2015, and VOCs control effectiveness of a major refinery after 6 years.
2022 Vol. 42 (7): 3046-3057 [Abstract] ( 157 ) [HTML 1KB] [ PDF 1762KB] ( 441 )
3058 Traceability and emission characteristics analysis of VOCs from typical plates in customized furniture
TIAN Jiao, QIN Ye-xia, YANG Shuai-jun, Lü Ye-tong, HUANG Hao-min, YE Dai-qi
The composition, concentration and emission law of VOCs from five typical customized furniture plates were explored by using a 1m3 small environmental chamber under certain conditions. The results showed that 54 target compounds were identified from the five plates, and the main components were OVOCs and alkanes, accounted for 71.37%~85.77% and 11.79%~24.84%, respectively. The TVOCs concentration of different plates were quite different. The TVOCs concentration of veneer -medium density fiberboard(MDF) was as high as 836.49μg/m3, which was much higher than other boards, while it was the lowest in solid wood ecological board, which was the most environmentally friendly. The emission concentrations of VOCs from five kinds of boards were measured hourly. It was found that the relative emission concentrations of formaldehyde were as follows: veneer MDF > moisture-proof board > veneer particle board > solid wood ecological board > PVC blister board; the emission concentration of TVOCs (except formaldehyde) was as follows: veneer particle board > veneer MDF > PVC blister board > moisture-proof board > solid wood ecological board. In these five plates, formaldehyde, n-hexane and ethyl acetate were the main substances, and the concentration contribution of formaldehyde accounts for 40.44%~82.59% of TVOC. At the same time, based on VOCs emission characteristics from five kinds of plates, the traceability analysis of various compounds is helpful for the source control of VOCs pollution.
2022 Vol. 42 (7): 3058-3067 [Abstract] ( 160 ) [HTML 1KB] [ PDF 622KB] ( 802 )
3068 On-line characterization of nitrated polycyclic aromatic hydrocarbons in naphthalene secondary organic aerosol
HU Hui-min, HUANG Ming-qiang, ZHU Min-cong, WANG Wei-chao, GU Xue-jun, HU Chang-jin, ZHAO Wei-xiong, ZHANG Wei-jun
Nitrated Polycyclic aromatic hydrocarbons (NPAHs) widely exist in atmospheric aerosol particles and are important components of brown carbon. Naphthalene and other polycyclic aromatic hydrocarbons (PAHs) are vital precursors of NPAHs. To explore the effect of NO2 on formation of NPAHs, the NPAHs components in secondary organic aerosol (SOA) formed from the photooxidation of naphthalene with different concentrations of NO2 were on-line measured using aerosol laser time-of-flight mass spectrometer (ALTOFMS) in this study. Experimental results demonstrated that NO2 had promotion effect on the generation of NPAHs and formation of SOA. Using ALTOFMS on-line detection, followed by Fuzzy C-means (FCM) algorithm cluster analysis, and combined with off-line electrospray ionization mass spectrometer verification, it was determined that naphthols and carboxyls were the main components of naphthalene SOA particles without NO2, and nitro-naphthalene, dinitro-naphthalene, nitro-naphthol, dinitro-naphthol and their derivatives via the nitration of OH-naphthalene adduct and naphthol products of naphthalene were identified as the major constituents of SOA with NO2. These provided the experimental basis for exploring the chemical components and formation mechanism of NPAHs under the background of high NOx concentration in urban atmosphere.
2022 Vol. 42 (7): 3068-3076 [Abstract] ( 116 ) [HTML 1KB] [ PDF 821KB] ( 535 )
3077 Experimental study on electrostatic precipitator removal of fine particles with pre mixed spray
DENG Quan-long, ZHUANG Ding-ding, DING Hou-cheng, LIAN Zhi-xu, XU Yuan-di
In order to improve the collection efficiency of fine particles via electric field and achieve the requirement of ultra-low emission of particles, a novel pre mixed spray electrostatic precipitator was designed by separating the spray part and electronic field to enhance the agglomeration between particles and droplets. The influence of electric field voltage, plate spacing, air velocity, spray pressure and inlet dust concentration on the efficiency of dust removal was investigated in detail. The results showed that with the increase of voltage, the dust removal efficiency increased, the increasing tendency raised quickly and then slowed down to steady state. Reducing the distance between plates or the wind speed could raise the dust removal efficiency while the treatment air volume reduced. With the increasing of spray pressure, the dust removal efficiency increased firstly and then decreased. When the pressure value was 6MPa, the dust removal effect showed the largest value. The influence of inlet concentration of dust on the removal efficiency was quite low, the removal efficiency of particles with the size less than 2.5μm was large as 98.5%. In summary, the dust removal efficiency of pre mixed spray electrostatic precipitator was significantly enhanced compared with that of single spray or electrostatic precipitator, which has significant reference value for the design of ultra-low particulate emission devices.
2022 Vol. 42 (7): 3077-3083 [Abstract] ( 115 ) [HTML 1KB] [ PDF 647KB] ( 328 )
3084 Catalytic performance of FeMn-based monolithic catalysts for toluene and chlorobenzene catalytic combustion
WANG Xiao-qiang, YANG Ning, XU Li, LI Xiang-peng, WANG Yu
This research compared a series of FeMn-based monolithic catalysts prepared by incipient impregnation, ultrasonicassisted impregnation and redox-precipitation. These catalysts were characterized by various techniques such as BET, SEM, XRD, H2-TPR and XPS. The results suggested that the redox-precipitation sample owned layered structure, which exposed larger specific surface area and more active site. In addition, the reduction temperature of the redox-precipitation sample was the lowest and Mn4+ content was the highest among the samples, which enhanced its catalytic performance. The redox-precipitation sample had the best catalytic performance for toluene and chlorobenzene combustion, its T50/T90 of toluene were 200℃ and 270℃, and the T50/T90 of chlorobenzene were 261℃ and 320℃, respectively. Meanwhile, its stability was also preferable than the other samples.
2022 Vol. 42 (7): 3084-3092 [Abstract] ( 161 ) [HTML 1KB] [ PDF 902KB] ( 411 )
Water Pollution Control
3093 Effect of FeS on reactive brilliant red X-3B removal effect and degradation process in CW-MFC system
ZHAO Lian-fang, YU Xue-qing, LU Zong-ren, LIU Cheng, LI Ying
In the self-constructed wetland-microbial fuel cell (CW-MFC), the effect of FeS on the decolorization and degradation process of reactive brilliant red X-3B was studied by using gravel filter as a control. The results showed that the addition of FeS in the underlying region could significantly improve the decolorization effect and the system electricity generation performance of CW-MFC on reactive brilliant red X-3B. The addition of FeS made the system decolorization rate reach 99.83% under the conditions of influent of 200mg/L reactive brilliant red X-3B and glucose of 100mg/L. The maximum power density in FeS group reached 0.849W/m3 with influent of 100mg/L reactive brilliant red X-3B and glucose of 200mg/L. The decolorization of reactive brilliant red X-3B in the system mainly occurred in the bottom layer and anode regions, which could be seen from the UV full-wavelength scanning and GC-MS spectrum that FeS promoted the breakage of azo double bonds in this region, and was conducive to the further degradation of the decolorization products aniline, triazine structure and naphthalene ring structure.
2022 Vol. 42 (7): 3093-3102 [Abstract] ( 124 ) [HTML 1KB] [ PDF 812KB] ( 243 )
3103 Degradation of sulfamethoxazole in water by Fenton-like method using Fe3O4-nZVI
XIE Xin-zhuo, ZHONG Jin-kui, LI Jing, ZHENG Bo-Wen
Fe3O4-nZVI was prepared by co-precipitation and liquid phase reduction method. The obtained Fe3O4-nZVI was used as catalyst of Fenton-like reaction to degrade sulfamethoxazole (SMX) in water. The effects of H2O2 concentration, Fe3O4-nZVI dosage, pH of solution, SMX concentration and temperature on SMX degradation were investigated. The charactering results of SEM, EDS, XRD and XPS showed that the magnetic composite material with nanometer size was successfully prepared. The batch experimental results showed that the degradation rate of SMX in Fenton-like system increased as the increase of H2O2 concentration, Fe3O4-nZVI dosage and temperature, and decrease of pH in studied experimental ranges. The fitting parameters of kinetic showed that SMX degradation fitted the pseudo-first-order kinetic model. Under the given conditions, which were H2O2 10mmol/L, Fe3O4-nZVI 0.8g/L, pH=3, SMX 10mg/L, and reaction temperature 25℃, the degradation rate of SMX was 99.61% at 180min. The magnetization of Fe3O4-nZVI was 105.52emu/g, indicating it was easy for magnetic recycle. Reused experiments showed that Fe3O4-nZVI had excellent reactivity and stability. Free radical quenching experiments showed that the oxidation of ·OH played a key role on degrading SMX in water.
2022 Vol. 42 (7): 3103-3111 [Abstract] ( 157 ) [HTML 1KB] [ PDF 603KB] ( 726 )
3112 Preparation of g-C3N4 nanosheets doped with proline and its degradation of RhB
JIANG Jun, NI Qian-qian, KE Xin, YAN Zheng
Proline doped g-C3N4 nanosheets were successfully prepared by a feasible hydrothermal and calcination approach. Properties of the photocatalysts, including structure, morphology, composition and photoelectric characteristics, were systematically analyzed by FTIR, XRD, SEM, BET, XPS, UV-vis DRS, PL, and Electrochemical workstation. The results showed that the addition of proline could autonomously exfoliate the precursors to make nanosheets of g-C3N4 and increase the specific surface area of the catalysts. Furthermore, the energy band structure of the catalysts, visible light absorption ability, and the separation rate photogenerated carriers of as-prepared g-C3N4 were remarkably improved. The photocatalytic performance was investigated by degradation of Rhodamine B under simulated visible light irradiation. The optimal doping conditions was herein obtained. At 1% addition amount of doped proline (PCN-1%), over 99% pollutants could be degraded under 60min irradiation of visible light. The degradation rate of PCN-1% (0.0271min-1) was 10.04 times compared with that of the traditional bulk carbon nitride (BCN, 0.0027min-1), evidencing the notably improved photocatalysis properties of g-C3N4.
2022 Vol. 42 (7): 3112-3120 [Abstract] ( 128 ) [HTML 1KB] [ PDF 913KB] ( 538 )
3121 Start-up and performance study on the simultaneous nitrification-endogenous denitrification phosphorus removal (SNEDPR) in the biological process of the moving bed biofilm reactor (MBBR)
JING Shuang-yi, SONG Zi-yang, LIU Chao, LI Wei-ping, LI Qi, ZHANG Tie-jun
This study assessed the feasibility of simultaneous nitrification, endogenous denitrification and phosphorus removal (SNEDPR) for enhancing the nitrogen and phosphorus removal by the process of moving bed biofilm reactor (MBBR), an MBBR operated alternately by continuous aeration and stirring/aeration was adopted for simulating the treatment of domestic sewage with magnetic filler as the carrier. The performance of nitrogen and phosphorus removal during SNEDPR initiation was investigated, and the structural changes of functional microflorae were analyzed by fluorescence microscopy and high-throughput sequencing technology. The results showed that after two stages of operation, the removal rates of ammonia nitrogen and phosphorus reached 97.6% and 85.37% respectively, and the NO2--N, NO3--N and COD concentrations in the effluent were 1.3949, 3.88 and 20.4mg/L respectively. The simultaneous nitrification and endogenous denitrification rate (SNEDR) increased from 0.07% to 86.35%. The improvement in SNEDR at the aerobic stage decreased the NOx--N concentration in the effluent, improved the denitrification performance of the system and promoted the storage capacity of carbon source at the anaerobic stage. The fluorescence microscopy and high-throughput sequencing results showed that after 53d of operation, the diversity of microbial community was improved significantly, and at the same time, the increase in abundance for GAOs, AOB and NOB (from 3.3%, 0.84% and 0.66% in the inoculated sludge to 27.08%/20.48%, 1.45%/1.76% and 1.05%/0.85% in the system respectively) and the presence of PAOs and DPAOs guaranteed the performance of nitrogen and phosphorus removal for the system, and realized the coupling of EBPR and SNED by the MBBR process.
2022 Vol. 42 (7): 3121-3129 [Abstract] ( 138 ) [HTML 1KB] [ PDF 664KB] ( 246 )
3130 Photocatalytic reduction of Cr(VI) by pyridine doped graphitic carbon nitride
LIU Fang-yuan, LIU Ya-nan, LU Shuai-shuai, CHEN Huan, JIANG Fang
In this paper, melamine and pyridine dicarboxylic acid were used to synthesis organic macromolecule precursors by hydrothermal synthesis, and graphitic carbon nitride (x% py-CN) modified with pyridine was designed. The x% py-CN catalysts were characterized by TEM, XRD, XPS, FT-IR and EIS. The photocatalytic reduction performance of x% py-CN catalyst was investigated by using Cr(VI) as the target pollutant. The results showed that 10% Py-CN had the best photocatalytic performance under simulated sunlight, and the photocatalytic reduction rate of 15mg/L Cr(VI) reached 85% under 3h irradiation. The improvement of the photocatalytic activity of catalysts was attributed to the fact that the modification of pyridine could effectively improve the separation efficiency of photogenerated electron hole pairs. In addition, the repeated cycle experiment showed that the catalyst has good stability and recycling ability, and had a good application prospect.
2022 Vol. 42 (7): 3130-3139 [Abstract] ( 163 ) [HTML 1KB] [ PDF 1121KB] ( 425 )
3140 Alternating electric field combined with iron-modified biomass to enhance the deep-dewatering of municipal sludge
LI Ya-lin, CHEN Gao-ang, SUN Li-li, WANG En-ci, SONG Yu-qing, SUN Chen-xin
To realize deep-dewatering of municipal sewage sludge, the combined alternating electric field (AEF) electroosmosis technology was developed with iron modified biomass as the skeleton for disposal of sludge. Based on a single-factor experiment, the effect of the combined technology on sludge dewatering behavior was studied. Moreover, technical parameters of sludge dewatering were optimized with the response surface method (RSM). After mixing the sludge with corn stalks modified by FeCl3 of 0.03g/mL, in the AEF of unequal duty cycle at 4.33:1, voltage at 17.22V/cm, modified biomass dosage at 96.81mg/g DS, modified biomass moisture at 61.91%, biomass particle size at 1.05mm, and anode-cathode distance at 2.10cm, the dewatered sludge with a moisture content of 58.21% could be obtained, and the dewatering energy consumption was 0.0148kW·h/kg RW (Removed water). According to scanning electron microscope (SEM) characterization of the dewatered sludge, iron modified biomass well supports the sludge as the skeleton, which was conducive to the mechanical strength and permeability of the sludge. According to thermogravimetric analysis (TGA), the upper and lower combustion process in the dewatered sludge could be divided into the stage of precipitation of free water and bond water, the stage of precipitation and combustion of volatile, and the stage of decomposition of inorganic salts. The dewatered sludge mixed with iron modified biomass showed higher organic content and faster combustion.
2022 Vol. 42 (7): 3140-3148 [Abstract] ( 112 ) [HTML 1KB] [ PDF 918KB] ( 236 )
3149 Effect of EDTA-2Na/Fe(Ⅱ) on nitrate reduction in autotrophic biological system
ZHANG Wen-bo, LI Xiao-ling, LIU Xin-yi, ZHANG Jia-ying, ZHOU Jun-cai, MENG Wen, ZHANG Peng-cheng
The initiation of iron mediated denitrification was studied in an anaerobic sequenced batch biofilm reactor (ASBBR) with a fixed concentration of nitrate and ferrous sulfate, supplemented with EDTA-2Na according to different gradient conditions for a long period of cultivation domestication. Meanwhile, the effects of different EDTA-2Na/Fe(Ⅱ) on iron autotrophic denitrification process and the dissimilatory nitrate reduction to ammonium (DNRA) were also explored in this study. The results showed that after 65days of cultivation and domestication, the reactor operated successfully and stably, and the removal rate of NO3--N was up to 99.70%. When EDTA-2Na/Fe(Ⅱ) < 1.50, only iron autotrophic denitrification was performed with the highest removal rate of NO3--N of 71.70%; When EDTA-2Na/Fe(Ⅱ) ≥1.50, iron autotrophic denitrification and DNRA were carried out simultaneously in the reactor, and the highest removal rate of NO3--N was 99.70%. It was worth noting that when EDTA-2Na/Fe(Ⅱ)=1.50, the iron autotrophic denitrification rate reached the maximum value of 1.63mg/(L·h), and the ammonia production of DNRA also reached the maximum value of 9.75mg/L. Visual MINTEQ simulation results showed that the molar ratio of EDTA-2Na to Fe (Ⅱ) affected the existing forms of EDTA-2Na and Fe (Ⅱ) in the influent. The larger the molar ratio, the higher the concentration of FeEDTA2- and the stronger the bioavailability of Fe (Ⅱ). Thr ough microbial population analysis, it was found that the dominant bacteria were Brucella, Castellaniella, Ochrobactrum, Pseudomonas as well as Citrobacter. Among them the first four bacteria were related to denitrification process, while Citrobacter was related to DNRA process and was only appeared under the conditions of EDTA-2Na/Fe(Ⅱ)=1.50 and 1.75 in this research. Therefore, the above results could throw light on further exploring the relationship between DNRA and denitrification.
2022 Vol. 42 (7): 3149-3155 [Abstract] ( 186 ) [HTML 1KB] [ PDF 467KB] ( 399 )
3156 Sludge-based biochar enhances treatment performance of activated sludge systems
ZHAO Bing, LIU Xiao-yan, LI Sheng-hong, ZHU Fen-fen
This study investigates the sludge-based biochar to enhance the treatment performance of activated sludge systems. The highest COD reduction rates of 72.9% and 41.1% were found for activated carbon and sludge-based biochar, respectively, into the activated sludge of anaerobic tank in the A2O process. The highest reduction rate of TN was 74.1%, which was more effective than that of activated carbon. Characterization showed that activated sludge was more easily attached to sludge-based biochar and had a larger specific surface area. Activated carbon, sludge-based biochar and defatted sludge-based biochar were added in the anaerobic tank of A2O pilot plant at the frequency of one addition per sludge age. The results showed that adding sludge-based biochar had better reduction effect on COD, TN and TP than adding activated carbon. Compared with the addition of activated carbon, adding defatted sludge-based biochar had little difference in COD and TN reduction, but the average reduction rate of TP was 85.6%, which was more effective than that of activated carbon. In conclusion, biochar treatment (BT) process is more powerful than powdered activated carbon treatment (PACT) process in treating domestic sewage, and defatted sludge-based biochar is more economical as a by-product of sludge lipid extraction.
2022 Vol. 42 (7): 3156-3163 [Abstract] ( 251 ) [HTML 1KB] [ PDF 1728KB] ( 315 )
3164 Study on dye removal by dual Z-Scheme MIL-88A (Fe)/Ag3PO4/AgI photo-Fenton catalyst
BAN Sa, ZHU Hao, WANG Tong, HUANG Na, CAO Jin-rong, ZHANG Hui-jie, FAN Hua, ZHOU Rui, YIN Da-xue
In this study, the double Z-type ternary composite MIL-88A (Fe)/Ag3PO4/AgI(MAI) was successfully synthesized by in-situ precipitation method and ion exchange method using MIL-88A (Fe) as the support. MAI was applied to the photo-Fenton system to efficiently remove Rhodamine B(RhB) from dye wastewater. The rod-shaped MIL-88A (Fe) was used as a carrier to reduce the agglomeration of Ag3PO4 and AgI particle. The formation of a double Z-type heterojunction reduced the recombination of electorn-hole pairs and improved photocatalytic activity. Under the best optimized condition of 0.5g/L catalyst, initial pH 3.0, 0.4mmol/L H2O2, 100mL 20mg/L RhB, RhB was completely degraded RhB within 20min. The catalyst could be maintained high catalytic property after 5cycles. In addition, free radical capture experiments and electron spin resonance experiments showed that h+, O2·﹣and HO· were the main active substances in the MAI/Vis/H2O2 catalytic system. Finally, a possible mechanism for the catalysis of MAI was proposed.
2022 Vol. 42 (7): 3164-3173 [Abstract] ( 125 ) [HTML 1KB] [ PDF 1024KB] ( 467 )
3174 Enhanced removal of Cd(II) from aqueous solution by nanoscale zero-valent iron coupled with white rot fungus
ZENG Qiao-jing, ZHOU Xin, HUANG Chao, WANG Ping, CHENG Hao, ZHENG Xiao-yu, WANG Meng-xin, LIU Hao
A combined system of white rot fungus and nanoscale zero-valent iron (nZVI) was used to enhance the removal of Cd(II) from water. The effects of pH, Cd(II) initial concentration, temperature and nZVI dosage on Cd(II) removal were examined, and the impact of nZVI on intracellular and extracellular accumulation of cadmium by white rot fungus was investigated. The removal mechanism was analyzed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and three-dimensional excitation emission matrix fluorescence spectroscopy (3D-EEM). The results showed that the removal efficiency of 50mg/L Cd(II) reached 99.5% after 180 minutes at the conditions of pH 6, nZVI dosage of 0.1g/L and 30℃. The removal process of Cd(II) was found to follow the pseudo second-order kinetic model, and the extracellular adsorption by white rot fungus accounted for the main removal. The addition of nZVI promoted the extracellular adsorption of Cd(II) by white rot fungus. FTIR and XPS analysis showed that the hydroxyl, carboxyl and amino were involved in the adsorption of Cd(II), and the extracellular polymeric substances (EPS) of white-rot fungus could coordinate with iron in the inner layer to form a P-O-Fe bond, accelerating the formation of iron minerals such as lepidocrocite and magnetite that are rich in hydroxyl functional groups, thereby promoting the adsorption and removal of Cd(II) from the solution.
2022 Vol. 42 (7): 3174-3183 [Abstract] ( 132 ) [HTML 1KB] [ PDF 2313KB] ( 279 )
3184 Preparation of carbonized melamine sponge for photo assisted heavy oil adsorption
LIN Zi-mei, LOU Guo-sheng, KANG Yao-ming, LIU Hui-e, CHEN Shuang, YANG Xiang-yi
Carbonized melamine sponge (HMS) was prepared by calcining of melamine sponge (MS) in argon atmosphere. The carbonization effect of HMS was analyzed by SEM, XPS and FI-IR. The density, hydrophilicity, porosity, absorption spectra and compression resilience of the sponge before and after carbonization were measured. The results showed that MS was partly carbonized into HMS, with the hydrophobicity enhanced, the lipophilicity unchanged, and the porosity slightly reduced. HMS exhibited excellent light absorption and mechanical properties. The saturated adsorption volume of HMS sponge on light oil was 92.20cm3/g. Under 1sun irradiation (1kW/m2), the temperature of HMS sponge rose rapidly, which effectively reduced the viscosity of heavy oil in contact with its bottom surface and sped up the adsorption rate of heavy oil, with the adsorption capacity reaching about 99.1g/g. When HMS sponge repeatedly adsorbed heavy oil for 10times, its saturated adsorption capacity on heavy oil could maintain at higher than 81.00g/g. These characteristics made HMS sponge a promising high-efficiency, energy-saving and reusable oil spill adsorbent.
2022 Vol. 42 (7): 3184-3192 [Abstract] ( 131 ) [HTML 1KB] [ PDF 865KB] ( 291 )
3193 Effects of background ion types and concentrations on the co-transport of polystyrene microplastics / lead in saturated quartz sand
CHANG Bo-kun, CHEN Yi-ting, CAO Gang, HU Liang, Lü Jia-long, DU Wei, HU Fei-nan
In order to elucidate the effect of hydrochemical conditions on the transport of microplastics and heavy metals, and to clarify the coupling effect in the co-transport process of the two environmental pollutants and their response mechanism to environmental conditions preliminarily, the effects of background electrolyte ions with different valence and concentrations on the individual and co-transport behaviors of 1μm polystyrene microplastics (PS-MPs) and Pb2+ in a saturated one-dimensional sand column were studied. The experimental results showed that the increase in the background ion concentration or the valence would inhibit the individual transport ability of PS-MPs. When the Na+ concentration increased from 1mmol/L to 100mmol/L, the repulsive barrier between PS-MPs and quartz sand decreased by 1348kT; when the Ca2+ concentration increased from 1mmol/L to 100mmol/L, the repulsive barrier between PS-MPs and quartz sand decreased by 956kT. Pb2+ in PS-MPs/Pb2+ binary system could reduce the transport ability of PS-MPs, and the increase of the background ion concentration and the valence can weaken the inhibition of Pb2+ on the transport ability of PS-MPs. When the Na+ concentration increased from 1mmol/L to 100mmol/L, the repulsive barrier between PS-MPs and quartz sand decreased by 1100kT; when the Ca2+ concentration increased from 1mmol/L to 100mmol/L, the repulsive barrier between PS-MPs and quartz sand decreased by 543kT. The increase in the background ion concentration or the valence can promote the individual transport ability of Pb2+. PS-MPs can promote the transport of Pb2+ in the binary system of PS-MPs/Pb2+. When the background ion concentration was low, the transport of Pb2+loaded by PS-MPs was higher, and vice versa. For PS-MPs and Pb2+ individual transport systems, the increase in background cation concentration and valence can further shield the negative charges on the surface of PS-MPs and quartz sand, competitive adsorption the surface binding sites of quartz sand, inhibits the transport of PS-MPs while promoting Pb2+ transport. For the co-transport system of PS-MPs and Pb2+, the increase in background ion concentration and valence can weaken the inhibitory effect of Pb2+ on the transport ability of PS-MPs by adjusting the interaction between Pb2+ and PS-MPs and the surface of quartz sand. The competitive adsorption of background ions to PS-MPs’ surface sites and the shielding effect on charges affect the transport ability of Pb2+ loaded by PS-MPs.
2022 Vol. 42 (7): 3193-3203 [Abstract] ( 178 ) [HTML 1KB] [ PDF 818KB] ( 403 )
3204 Study of DOM removal in surface water by forward osmosis
WEI Yong, WU Hong, LI Tian, LUO Zheng-bo, LI Xian-jian, WEI Qin-zheng
Forward osmosis (FO) filtration was carried out with influent from Ge Lake after sand filtration, and draw solution of sodium chloride. Different factors influencing FO performance were examined and the cleaning process of the fouled membrane was also conducted to investigate the reversibility of the FO membrane fouling. The results showed that increasing the concentration of the draw solution or the operation temperature and membrane surface velocity could enhance the permeate flux. In addition, the FO could effectively remove the main four types of dissolved organic matters (DOM) in Ge Lake, i.e. the soluble microbial metabolites, tryptophan-like substances, fulvic acids and humic acids, with DOC and UV254removal ratios both above 96%. Furthermore, the membrane cleaning performance exhibited that the flux of the fouled membrane in a short-term filtration can be almost fully recovered with just hydraulic washing, while that in a long-term filtration couldn’t be generally recovered with hydraulic washing, but with ultrasonic cleaning. Finally, the membrane elution was analyzed and it was found that the tryptophan-like substances and fulvic acids were key membrane fouling contributors.
2022 Vol. 42 (7): 3204-3211 [Abstract] ( 142 ) [HTML 1KB] [ PDF 1368KB] ( 215 )
3212 Enhancement of glucocorticoid reduction transformation by PRB modified with rGO@nZVI-BC
SUN Bo-yu, HAN Dong-mei, MA Wei-fang
In order to synthesize an environmentally useful material, rGO@nZVI-BC, and to design a permeable reactive barrier (PRB) employing this material for the effective removal of fluorinated glucocorticoids (FGCs) from groundwater. The results indicated that the inhibitory process could be represented using an improved Yoon-Nelson model, with adsorption and biodegradation rate constants of 0.485 and 0.035d-1, 0.233 and 0.029d-1, respectively, in rGO@nZVI-BC and soil systems. The primary mechanism for increasing the efficacy of the process is by strengthening the adsorption and biodegradation activities. At the first stage of operation, adsorption was found to be the dominant mechanism, accounting for approximately 76.12% of the total removal. The mechanism of bioaugmentation is that nZVI acts as an electron donor for the reduction of GCs, thus, enhancing the defluorination reduction function. This component contributed to approximately 87.06% of the total, which is accompanied by dehydroxylation, oxidative side chain degradation, and ring-opening degradation. Additionally, the increased relative abundance of the functional bacteria belonging to the reductive dehalogenation taxa (Xanthomonadaceae, Desulfuromonas, and Sphingomonadaceae) indicated the efficiency of rGO@nZVI-BC. This research provides a practical strategy for preventing and controlling the contamination of groundwater.
2022 Vol. 42 (7): 3212-3223 [Abstract] ( 158 ) [HTML 1KB] [ PDF 770KB] ( 247 )
3224 Uncertainty analysis of groundwater pollution simulation model
LUO Cheng-ming, LU Wen-xi, WANG Zi-bo, CHANG Zhen-bo
In order to simultaneously analyze the effect of source and sink items and hydrogeological parameters uncertainty on the output of groundwater pollution numerical simulation model, a gangue dump site in Fushun City was taken as an example to study. Firstly, the groundwater pollution numerical simulation model of the site was established with sulfate ion as the simulation factor. Then, local sensitivity analysis and global sensitivity analysis were used to analyze the sensitivity of the simulation model parameters, and the results of thetwowere compared. Finally, two parameters that have a great impact on the model output were selected as the random parameters of the model.In order to reduce the calculation load caused by repeatedly calling the simulation model, four methods of Kriging(KRG), kernel extremelearning machine(KELM), support vector machine(SVM) and BP neural network (BPNN) were used to establish the surrogate model of the simulation model for three observation wells respectively. According to the fitting effect of the four surrogate models in different wells, a surrogate model with the best performance was selected for each well, Monte Carlo stochastic simulation was completed by using the optimized surrogate model. Finally, statistical analysis and risk assessment were carried out on the results of random simulation. The results show that when the confidence was 80%, the confidence intervals of the concentration values of the well 1,2,3 were 211.48~845.04mg/L, 0~406.98mg/L, 231.42~958.37mg/L. In addition, according to the groundwater quality standard and the pollutant concentration distribution function curve of each well, the probability that the water quality of well 1 and well 3 met the class V water standard was 90.1% and 93.1% respectively, and the probability that well 2 met the class III water standard was 80.7%, so as to provide a reasonable basis for groundwater resource management and pollution prevention and control.
2022 Vol. 42 (7): 3224-3233 [Abstract] ( 131 ) [HTML 1KB] [ PDF 911KB] ( 413 )
3234 Numerical simulation of groundwater remediation of hexavalent chromium contaminated site by the bio-permeable reactive barrier
DIAO Wen-qin, SONG Jian, WANG Lin, WU Jian-feng, LIU Yuan-yuan, WU Ji-chun
In order to reduce Cr(VI) in groundwater, the common electron donor (molasses) and dithionite in the biological reaction process were selected as the reactant and biocide of PRB, for the purpose of promoting the biochemical reaction to reduce Cr(VI) and preventing the bioclogging effect. PFLOTRAN software was adopted to simulate the biochemical reaction process of PRB with molasses as the reaction material and dithionite as the biocide to remove heavy metal pollutant in the heterogeneous aquifer. The results show that the PRB technique can reduce the Cr(VI) concentration to below 0.1mg/L; the bioclogging effect can be avoided by designing the concentration of biocide, injection rate and initial concentration of molasses, in order to achieve the dual goal of removing Cr(VI) and improving the longevity of PRB. The results of research can provide a decision-making basis for the optimal design plan of heavy metal contamination remediation in the groundwater for similar sites.
2022 Vol. 42 (7): 3234-3243 [Abstract] ( 176 ) [HTML 1KB] [ PDF 1922KB] ( 334 )
3244 Stochastic simulation of groundwater pollution considering uncertainty of parameters and boundary conditions
XU Ya-ning, LU Wen-xi, WANG Zi-bo, JIA Shun-qing, WANG Han, PAN Zi-dong
In order to investigate the influences of random changes in model parameters and boundary conditions on the output uncertainty of groundwater solute transport model, combined application of Monte Carlo simulation and risk assessment were applied to illustrate the uncertainty analysis results of a hypothetical example. Firstly, a numerical simulation model of groundwater solute transport was established, then the parameters with greater impacts on the model output screened by local and global sensitivity analysis, together with the boundary conditions of the model (the first type of boundary conditions—head value) were set as random variables.Then the Gaussian Process Regression (GPR) method of optimizing hyperparameters was employed to establish an alternative model of the simulation model to complete the Monte Carlo stochastic simulation. Finally, statistical analysis and interval estimate of the results of random simulation were carried out, and the probability distribution function of pollutant concentration was used to estimate the risk of different degrees of pollution of observation wells 1, 2, and 3. The results show that when the confidence level was greater than 80%, the confidence intervals of the pollutant concentration values in observation wells 1, 2, and 3 were 34.77~35.03, 57.74~58.04, and 100.07~100.69mg/L, respectively. In addition, in observation wells 1, 2, and 3, the risk of slight pollution was 6%, 100% and 100%, respectively; the risk of moderate pollution was 0%, 0% and 99.6%, respectively; the risk of heavy pollution was 0%, 0%, and 0.5%, respectively. The present study can provide a reliable reference for pollution remediation and rational utilization of groundwater.
2022 Vol. 42 (7): 3244-3253 [Abstract] ( 142 ) [HTML 1KB] [ PDF 1373KB] ( 658 )
Solid Waste
3254 Physicochemical properties and reuse of municipal solid waste fine fraction: Case of an aged landfill site in Zhejiang Province
ZHENG Kang-qi, CHEN Ping, QIU Yu-feng, GUO Qi-meng, CHEN Yan-bo, YUAN Miao-xin, ZHAN Liang-tong
This study is to investigate the physicochemical properties for the fine fraction (particle size <15mm) of the excavated municipal solid wastes (MSWs) with fill ages ranging from 23 to 37a. The composition, physicochemical properties and leaching solution properties of the materials were measured and analyzed. The experimental results showed that the particle size ranges (2~15mm, 0.075~2mm and <0.075mm) for the materials account for 42.9%~53.9%, 40.9%~44.1% and 5.1%~13.0%, respectively. The materials can be classified as a fine-grained sand. With a increase of fill age, the characteristic particle size d50 and d10 decreased, the specific gravity increased greatly, and tended to be stable after 30 years. The organic matter content (18.1%~19.1%), the content of nitrogen, phosphorus and potassium, the pH of the leaching solution (7.26~8.30), and the electrical conductivity (1.08~2.51mS/cm) all met the standard of Organic media for greening. The contents of Cu, Zn, Cd, Cr and Ni in the materials exceeded the standards of Soil environmental quality Risk control standard for soil contamination of agricultural land, Planting soil for greening and Organic media for greening. The calculated value of Nemerow comprehensive pollution index was as high as 15.48~17.95, indicating the materials were heavily contaminated. It was found that the heavy metals concentrated in the fine-grained fraction with particle sizes less than 2mm. It was suggested that the fine fraction should be further screened into two parts with a particle size of 2~15mm and less than 2mm. For the part with particle size less than 2mm, the technology of microbial induced carbonate precipitation could be used to stabilize the contained heavy metals. The treated materials can be reused as a planting soil layer for landscaping, landfill closure and abandoned mine site reclamation.
2022 Vol. 42 (7): 3254-3264 [Abstract] ( 383 ) [HTML 1KB] [ PDF 1326KB] ( 445 )
Soil Pollution Control
3265 Pollution characteristics and environmental risks of ammonia nitrogen in retired nitrogen fertilizer plant sites
CHEN Yun, JIANG Deng-deng, YANG Kun-hua, ZHU Xin, KONG Ling-ya, LI Xu-wei, DENG Shao-po
Based on the concentrations of NH4+-N in soil, groundwater, soil gas, and indoor air from abandoned nitrogen fertilizer plants sites, the polluted level and distribution characteristics of NH4+-N in these sites were analyzed, the human health risks for exposure to the NH4+-Nin soil and groundwater were evaluated, and the effects of ammonia volatilization on the risk of irritating odors and indoor air quality, as well as the impact on nearby surface water and downstream groundwater with NH4+-N migration and transformation was also evaluated. The results showed that the concentrations of NH4+-N in the soil and groundwater significantly varied in all four sites. The highest concentrations of NH4+-N in the soil of the four sites were as high as 12700.00, 2420.00, 2920.00, and 2370.00mg/kg, respectively, and the highest concentrations in the groundwater were up to 7550.00, 5100.00, 847.00, and 3760.00mg/L, respectively. The high concentration of NH4+-N was mainly distributed around production and the sewage treatment areas. The vertical distribution of NH4+-N in soil was different in four sites, in which the NH4+-N concentration mainly decreases with the increase of depth in site I, in which the soil is mainly clay, while the NH4+-N concentration generally showed an increasing trend with increasing depth in site II, III and IV that the soil is mainly silt sand or silty clay. The hazard quotient of NH4+-N was calculated in site I with a value of 1.54, which slightly exceeded the acceptable risk level (1.0). The concentrations of NH3 (g) detected in soil gas and indoor air were ≤9.88mg/m3 and ≤0.18mg/m3, respectively, which had no adverse effects on indoor air quality. The concentration of groundwater NH4+-N in site I and II nearby the surface water exceeded 1.05to 409.33times the Category IV (1.5mg/L) standard in the Environmental Quality Standards for Surface Water. The concentrations of groundwater NH4+-N in site III and IV were slightly decreased during four times monitoring and the accumulation of nitrate nitrogen was found in the downstream monitoring wells. The results suggested that the human health risk of NH4+-N in the four sites were low, and the impact on indoor air quality was weak. However, the groundwater NH4+-N in the site was a pollution source for nearby surface water and downstream groundwater environment in the long term, and the nitrate nitrogen transformed by NH4+-N was more likely to migrate downstream.This study provides a scientific basis and practical experience for considering the environmental pollution risks of surface water and groundwater when dealing with NH4+-N in a site of nitrogen fertilizer plants in the future.
2022 Vol. 42 (7): 3265-3275 [Abstract] ( 125 ) [HTML 1KB] [ PDF 780KB] ( 381 )
3276 Shear strength and leaching characteristics of solidified lead-zinc-cadmium composite heavy metal contaminated soil under long-term freeze-thaw cycles
WANG yao, YANG Zhong-ping, ZHOU Yang, CHANG Jia-zhuo, LI Deng-hua, LUO Jun
In order to evaluate the shear strength and leaching characteristics of the solidified composite heavy metal contaminated soil after long-term freeze-thaw cycles (up to 90days (times)), triaxial compression test and toxicity characteristic leaching procedure test were carried out on the lead-zinc-cadmium composite heavy metal contaminated soil after solidification/stabilization with composite curing agent of cement, quicklime and fly ash. The results show that the angle of internal friction only increased significantly to 3 freeze-thaw cycles, and the increase rated was as high as 96.3%; while the overall trend of cohesion continued to decline by 30 freeze-thaw cycles, and there was no significant change afterwards, and the final decline rate reached 54.23%; the leaching concentration of Pb2+, Zn2+, Cd2+, and the EC value of the extract is proportional to the number of freeze-thaw cycles; the pH value of the extract decreases after long-term freeze-thaw cycles. And through scanning electron microscopy, we further explored the degradation mechanism of the shear strength and leaching characteristics of solidified contaminated soil under long-term freeze-thaw cycles. The results show that a large amount of delayed ettringite is formed in the solidified soil at the end of the freeze-thaw cycle, and its expansion during the formation process is the main reason for the loss of shear strength and the increase of heavy metal leaching concentration.
2022 Vol. 42 (7): 3276-3284 [Abstract] ( 153 ) [HTML 1KB] [ PDF 1255KB] ( 386 )
3285 Optimization of microplastics extraction from soil by density separation
LIN Jing, LI Zhen-guo, YU Guang-hui, ZHANG Yong, SONG Yan, WANG Guang-huai, JIANG Xiao-qian
To explore a simple, economic and reliable method for separation and extraction of microplastics from soil, eleven mixed solutions comprising saturated NaCl and NaI solutions with progressively changing volume ratios (F1~F11) were prepared. These mixed solutions were used as the flotation liquid to extract four types of microplastics including polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET) absorbed by soil with an improved protocol for flotation separation. The results showed that the total extraction rate of microplastics was only 55.83% when used purely NaCl saturated solution, while this extraction rate increased with an growing volume ratio of NaI in the mixture. The total extraction rate exceeded 90% when the volume ratio of saturated NaCl solution to NaI solution was 1:1and reached as high as 96.67% when using purely NaI solution. For all the eleven mixed solutions used, the extraction rates of PE and PS exceeded 86.67%, relatively higher than that of the other two types of microplastics. When using saturated NaCl solution alone, the extraction rates of PVC and PET were extremely low compared with that of 93.33% and 90% respectively in case the volume ratio of NaCl to NaI solution was 1:1, which were close to those obtained using NaI solution alone. Sum of the extraction rates of lower-density microplastics PE and PS was constantly higher than that of higher-density microplastics PVC and PET for all the eleven mixed solutions. However, the difference between extraction rates was neglectable among the mixed solutions F6 to F11. Based on the abovementioned results and considering factors such as economic cost, it is recommended that the mixture of saturated NaCl to NaI solution with a volume ratio of of 1:1 could be the optimal to extract microplastics in soil samples.
2022 Vol. 42 (7): 3285-3294 [Abstract] ( 221 ) [HTML 1KB] [ PDF 949KB] ( 656 )
3295 Screening of soil test plants and developing of their toxicity prediction models in China
LUO Jing-jing, WU Fan, ZHANG Jia-wen, LIU Zheng-tao, ZHANG Cong, WANG Xiao-nan
The lack of ecotoxicity data has always been a problem in the research of soil criteria and ecological risk assessment in China. The screening of native test plants can provide more ecotoxicity test materials, so as to obtain the ecotoxicity data of different species. In view of the sensitivity of plants to soil pollutants, potential test plants in China were screened from angiosperms according to the principles of distribution range, representativeness and accessibility. The results showed that 53 species of angiosperms in 13 families were widely distributed and easy to obtain, and could be used as native test plants. The result showed that ecotoxicity data of 12 plant species were relatively abundant. Therefore, the ecotoxicity prediction models were developed in this study. A total of 132 Interspecies Correlation Estimation (ICE) models were obtained for the 12 plant species, of which 88 were significant models (F-test P<0.05). Moreover, the selection and evaluation principle of the constructed ICE models were analyzed, and it was concluded that the ICE models with better prediction effects should meet the principle of cross-validation success rate≥80.00%, MSE≤0.62, R2 ≥0.76 and taxonomic distance≤4. Finally, 25ICE models were screened meeting the above principle, involving the mutual prediction of Gramineae-Gramineae and Cruciferae-Cruciferae. Among which when Avena sativa, Brassica rapa, Triticum aestivum, Zea mays and Lolium perenne were used as the surrogate species, the estimated toxicity values of predicted species were close to the actual tested values. The screening of the test plants and the establishment of the ecotoxicity prediction model can help generate ecotoxicity data and provide a scientific basis for soil pollution management and ecological risk assessment.
2022 Vol. 42 (7): 3295-3305 [Abstract] ( 148 ) [HTML 1KB] [ PDF 706KB] ( 422 )
Environmental Ecology
3306 Spectral characteristics of dissolved organic matter in the overlying water from Nanyi Lake
LI Hai-bin, XIE Fa-zhi, LI Guo-lian, ZHAI Hong-xia, GONG Xue, LIU Zhan, LUO Kun, YUAN Zhi-wei
In order to investigate the spectral characteristics and the sources of dissolved organic matter (DOM) in the overlying water of the Nanyi Lake. Herein, ultraviolet-visible (UV-Vis) absorption and three-dimensional fluorescence excitation-emission matrix (EEMs) were utilized to characterize the DOM. Parallel factor analysis (PARAFAC), fluorescence regional integration, correlation analysis, principal component analysis, and cluster analysis were applied to qualitative and quantitative analysis on the DOM. Based on the absorption parameters of a (440), E2/E3,E3/E4,SR of UV-Vis spectrum, it was found that DOM has humification and autogenesis characteristics. Moreover, E2/E3,E3/E4 and a(440) had positively correlation (P<0.01, P<0.05), and there was no significant correlation between SR and a(440) (P>0.05). The relative molecular weight of DOM increased with increasing the humic acid concentration, but the humic acid concentration cannot be used to determine the sources of dissolved organic matter (DOM). According to the a(440) values, the average concentration of dissolved organic carbon (DOC) in the water was calculated to be 26.79mg/L, and the DOC value in the outlet area of the lake was 10.15mg/L. From the analysis of fluorescence indices (β:α, FI, BIX, HIX, Fn(280), Fn(355)), the DOM exhibited low humification and highly autochthonous characteristics. The spatial distribution of the relative concentration of protein-like components (Fn(280)) was gradually increased from west to east, but the peak values of the relative concentration of humic-like components (Fn(355)) were observed in the estuary and lake outlet. Three fluorescence components of fulvic-like, tryptophan-like and humic-like identified by PARAFAC model were named as C1, C2, C3, and the contribution of C1, C2, C3 to the total fluorescence intensity were 21.96%, 13.36%, 84.21%, respectively. The results of the FRI method showed that the sum of the proportions of protein-like substances (region I +II) was as large as 49.65%, and it was mainly related to anthropogenic activities. Certain correlation was observed between the fluorescence components and the spectral parameters, and it was found that the C1, C3 and β:α, BIX were significantly negative correlated (P<0.001). C3 and β:α, BIX, Fn (355) were positive correlated (P<0.001). Based on the principal components analysis and cluster analysis, the DOM presented different characteristics between the 16sites in the Nanyi Lake. Overall, the DOM was significantly affected by endogenous input, and the control and management of pollutants released from the lake should be strengthened.
2022 Vol. 42 (7): 3306-3315 [Abstract] ( 147 ) [HTML 1KB] [ PDF 871KB] ( 372 )
3316 Spatial distribution and influencing factors of microplastics in water of Ulansuhai
HAO Ruo-nan, SHI Xiao-hong, LIU Yu, ZHANG Fan
In order to investigate the distribution of microplastics in the water body of Ulansuhai, different densities, sizes and shapes of microplastics at different locations of the lake were observed for abundance by test methods, and the effects of properties (density, shape and size) of the microplastics on the spatial distribution were analyzed at the same time. The results showed that the abundance ranges of microplastics at different sampling sites in the lake with density ranges less than 1.0g/cm3, 1.0 ~1.2g/cm3 and 1.2 ~1.5g/cm3 were (109.5±17.3) ~(642±160) n/L, (160.5±57.3) ~(588±104) n/L and (124.5±47.5) ~(502.5±80.2) n/L respectively. For the microplastics with density less than 1.0g /cm3, the abundance in the lake increased gradually from north to south, for the microplastics with density 1.0~1.2g/cm3, the abundance in the middle of the lake was higher than in the north and south of the lake, and for the microplastics with density 1.2~1.5g/cm3, the abundance showed a decreasing trend from north to south. the abundance ranges of microplastics of sizes 0.05~0.5mm, 0.5~2mm and 2~5mm in the lake were (70.5±8.8)~(805.5±154.7) n/L, (178.5±21.4) ~(742.5±112.3) n/L and 0~(217.5±22.8) n/L respectively. The abundance of microplastics of size 0.05~0.5mm showed an increasing trend from north to south, and of sizes 0.5~2mm and 2~5mm showed a decreasing trend from north to south. The abundance ranges of fibrous, fragmentary, membranous and massive shapes of microplastics were (499.5±92.3)~(1126.5±228) n/L, (30±4.8) ~(151.5±31.6) n/L, (4.5±0.8)~(229.5±61.6) n/L and (1.5±0.2)~(12±3.9) n/L respectively. The fibrous microplastics were dominant and evenly distributed at all sampling points, while the fragmentary, membranous and massive microplastics were of low abundance without obvious regularity. of all microplastics identified by Raman spectroscopy, polypropylene (43%) was the most common type, followed by polyvinyl chloride (18%), polyethylene terephthalate (18%), polyethylene (11.7%) and polystyrene (9.3%).
2022 Vol. 42 (7): 3316-3324 [Abstract] ( 172 ) [HTML 1KB] [ PDF 726KB] ( 447 )
3325 Analysis on spatial-temporal characteristics and Environmental Kuznets Curve of non-point source pollution in the Three Gorges Reservoir Area
FENG Lin, ZHANG Wan-ting, ZHANG Jun-ke, MAO Xin-hui, YU Xin, YE Cheng-song, CHANG Tian-yang
Total Nitrogen(TN) and total phosphorous(TP) emissions of agricultural non-point source pollution in 19 regions of the Three Gorges Reservoir Area(TGRA) were estimated from 2008 to 2018. Their spatial-temporal variation characteristics were further analyzed. According to Environmental Kuznets Curve (EKC) theory, a regression model based on panel data was constructed to explore the relationship between agricultural economy development and non-point source pollution emission intensity in TGRA. Our study found that TN emissions of agriculture decreased with fluctuation, and TP increased with fluctuation in TGRA. The average annual emissions of TN and TP in each region ranged from 374~6046 tons and 105~1267 tons respectively. Agricultural fertilizer and livestock breeding units contributed to more than 80% of total TN and TP. There were significant "inverted U-shape" EKC relationships to TN emission intensity, TN/TP emission intensity in livestock & poultry breeding unit and rural living unit, indicating that the turning points have been showed in these curves. There were significant "linear" EKC relationships to TP emission intensity in agricultural fertilizer unit, TN/TP emission intensity in aquaculture unit and farmland solid-waste unit, indicating a simultaneous growth with economy. The research finally proposed that agricultural fertilizer unit should upgrade the pollution prevention capacity, so as to improve rural living environment and reduce regional TN and TP emission.
2022 Vol. 42 (7): 3325-3333 [Abstract] ( 148 ) [HTML 1KB] [ PDF 755KB] ( 351 )
3334 Patterns of nitrogen and phosphorus losses in two catchments with contrasting underlying surfaces
XU Guang-zhi, SHAO Zhi-jiang, WANG Tao, HUANG Mei-yu, LI Ming-ming
To investigate the effects of different underlying surfaces on nitrogen (N) and phosphorus (P) losses via surface flow at a catchment scale, continuous daily monitoring of the surface flow and the concentrations of N and P was conducted in an agricultural catchment (AC) and a compound catchment (CC) in a hilly area of central Sichuan from 2019 to 2020. Results demonstrated a significant difference in the runoff process between the two catchments. The peak value of the surface flow was larger, the response speed was12 to 25min faster, and the annual runoff depth was 28.1% greater in CC than in AC. These results highlighted the effects of the contrasting underlying surfaces on the speed of runoff process, with the process being slowed down by the paddy fields and ponds in AC but speeded up by the impervious surfaces of the residential areas and roads in CC. During each rainfall event, the P concentration in runoff dropped more drastically, particularly in the late stage of the event, and the timing of peak P concentration was about 1.2hours earlier than those of N, respectively. Both the event mean concentration (EMC) and peak concentration of P or N were higher in CC than in AC. Nitrate-N was the main form of N losses in both catchments, accounting for 65.9% of the total N loss; while particulate P was the primary P form in the runoff, contributing to 67.5% of the total P loss. The N and P loads in CC were 3.01 and 4.03 times larger than those in AC, respectively, and the loss intensity of N and P in CC were 1.88 and 2.51times greater than those in AC, respectively. Therefore, the control of N and P losses from the compound catchments could be critical for the non-point source pollution control in hilly areas of central Sichuan in the future.
2022 Vol. 42 (7): 3334-3342 [Abstract] ( 174 ) [HTML 1KB] [ PDF 627KB] ( 659 )
3343 Identification and diagnosis of critical areas for ecological rehabilitation based on eco-security patterns and ecological vulnerability assessment - a case study over Wenshang County
LIU Jin-hua, YANG Shuo, Lü Yong-qiang
Selecting Wenshang County, Jining, Shandong Province as the study area, ecological security pattern was constructed based on the minimum resistance model, then the critical areas of ecological restoration were identified by using vulnerability assessment. Finally this study makes recommendations for protecting and restorating the ecology of the critical areas respectively. The results showed that Wenshang County contained 11ecological source areas, occupying 38.72km2, this county also had 35 ecological corridors with total length of 259.55km; the moderate and severe vulnerability area (594.32km2) dominated and shared 67.64% of total study area in Wenshang County. What’s more, the vulnerability of the central urban area was relatively high, and vulnerability of the southwestern low-lying area was low. In addition, five key areas of ecological restoration were identified, with a total area of 107.14km2, and they were mainly distributed in and around the central urban area. According to the location characteristics, these key areas were divided into three categories, and the strategies of ecological restoration were put forward separately to provide references for the overall protection and restoration of the ecosystem.
2022 Vol. 42 (7): 3343-3352 [Abstract] ( 173 ) [HTML 1KB] [ PDF 3562KB] ( 594 )
3353 The water quality criteria and ecological risks of copper under the influence of multiple factors
LIU Na, LI Ya-bing, LIU Hong-ling
In order to explore the impact of multiple factors on water quality criteria and ecological risks, the weighted species sensitivity distribution (WSSD), water effect ratio (WER) and biological ligand model (BLM) were used to derive the water quality criteria of copper for protecting aquatic organisms in Tai Lake. The criterion maximum concentration (CMC) of 1.43μg/L and the criterion continuous concentration (CCC) of 1.33μg/L were recommended as the water quality criteria of copper in Tai Lake. Joint probability curve (JPC) combining WER and BLM were used to further assess the ecological risks. There were 23.43% (WER) and 39.43% (BLM) probability of affecting 5% aquatic organisms during wet season in Tai Lake, respectively, while the traditional method overestimated the risks of copper in Tai Lake with a probability of 85.01%. These findings clearly suggest that the influence of multiple factors in the aquatic environment on water quality criteria and ecological risks cannot be ignored, currently environmental quality standard of copper adopted in China may not be able to protect aquatic organisms in specific areas such as Tai Lake. Considering multiple factors will obtain more reasonable water quality criteria and ecological risks assessment results, and avoid the phenomenon of “over-protection” or “under-protection”.
2022 Vol. 42 (7): 3353-3361 [Abstract] ( 116 ) [HTML 1KB] [ PDF 1280KB] ( 272 )
3362 Effect of halogen ions on photochemical activity of dissolved black carbon
TU Yi-na, TANG Wei, MA Yan-qiong, ZHANG Zhi-yu, TIAN Sen-lin, LI Ying-jie
Dissolved black carbon (DBC) is regarded as an important part of natural organic matter, however, its photochemical activity in the estuary is not clear. Here, the soybean straw DBC as the target, the changes in the formation rate (FT), the loss rate constants (ks’), and the steady-state concentrations ([T]ss) of 3DBC* in the presence of halogen ions in the estuary was explored by energy transfer isomerization of sorbic acid. The effects of halogen ions on 3DBC* electron transfer were studied by 2,4,6-trimethylphenol method. The results showed that halogen ions and ionic strength did not affect FT, but ks’ was decreased due to ionic strength and heavy atom effect of Br-, which increased [T]ss. The photochemical experiment of high concentration DBC confirmed that the ionic strength effect caused the aggregation of DBC molecules, which weakened the charge transfer of 3DBC* and inhibited the quenching of 3DBC*. For energy transfer of 3DBC*, it was not directly affected by halogen ions and ionic strength, but by the increase of [T]ss. Moreover, it was further found that halogen ions and ionic strength had no significant effect on the low-energy (ET < 250kJ/mol) 3DBC*, but only on high-energy 3DBC*and became obviously with the increase of the concentrations of halogen ions and ionic strength.
2022 Vol. 42 (7): 3362-3369 [Abstract] ( 146 ) [HTML 1KB] [ PDF 627KB] ( 321 )
3370 Correlation between biochar pore structure-nitrogen defects and tetracycline hydrochloride degradation
WANG Qing, NI Jing-xuan, GAO Yuan
Different pore structure and nitrogen defects of biochar materials were prepared in this work. The dynamic data of adsorption and persulfate-based advanced oxidation process (catalysis) systems were combined with the nitrogen adsorption -desorption test, X-ray photoelectron spectroscopy, Raman test and other characterization methods. They were used to analysis the correlation of pore structure-nitrogen defects and typical antibiotics (tetracycline hydrochloride) degradation systematically and deeply. The results showed that mesoporous surface area and specific surface area were most correlated with persulfate reaction. Nitrogen, especially graphite nitrogen (R2=0.9766) and pyridine nitrogen (R2=0.9596), was the most relevant elements to the reaction process of the system. In addition, the correlation between pore structure and the results was basically same in adsorption and catalysis processes. But nitrogen showed greater correlation in catalysis system than adsorption. Through quenching experiment, linear sweep voltammetry and Raman test, it was found that the catalysis was mainly dominated by singlet oxygen, which meant it was nonradical pathway. Finally, a better preparation direction for biochar materials to be used as activators in the persulfate-based advanced oxidation process of tetracycline hydrochloride was provided. Biochar materials with larger mesoporous surface area, larger specific surface area and more nitrogen, especially graphite nitrogen and pyridine nitrogen should be prepared for the catalysis of tetracycline hydrochloride.
2022 Vol. 42 (7): 3370-3377 [Abstract] ( 125 ) [HTML 1KB] [ PDF 711KB] ( 631 )
3378 Application of confocal Raman microscopy on the structure of sludge-based biochar
HUANG Ting, ZHANG Shan, SU Ming-xue, LI Ning
Confocal Raman microscopy method was utilized to analyze the structure changes of sludge-based biochar prepared at different pyrolysis temperatures (500~900 ). The results showed that there was a strong correlation between the fluorescence ℃ interference of Raman signal and the physicochemical properties of biochar. The Raman drift coefficient decreased with the pyrolysis temperature increasing, which was consistent with the changing trend of the volatile content, H/C and O/C ratio of sludge-based biochar. The correlation indices of the drift coefficient with the volatile content and the H/C ratio were 0.97 and 0.94, respectively, which revealed that the change of drift coefficient could be utilized to evaluate the change of volatile content and H/C ratio of biochar. In addition, the ratio of characteristic peak of biochar (D/G ratio) in the Raman spectra enhanced with the pyrolysis temperature increasing, which could represent the increasing process of the disorder degree of sludge-based biochar. The ratio of the valley region (V) to the D peak (IV/ID ratio) decreased with the pyrolysis temperature increasing, indicating that the proportion of defective fused aromatic ring structures increased. In addition, the ratio of ID1/IG1obtained by peak fitting was unobvious, while ID2/IG2 showed an increasing trend. The trend confirmed that the defects and amorphous structures were formed by the depositing compounds on the surface of carbon from low molecule fracture of side chain group. The ratio of IG1/IG2 decreased with the pyrolysis temperature increasing, indicating that the ratio of order to disorder of bond angle decreased following the increasing pyrolysis temperature. Therefore, Raman spectroscopy could be applied to characterize the sludge-based biochar, and reflect the evolution of its microstructure.
2022 Vol. 42 (7): 3378-3384 [Abstract] ( 161 ) [HTML 1KB] [ PDF 468KB] ( 530 )
3385 HPLC-MS-MS method for low level DNA methylation value determination in ecological species
HU Jun-jie, WU Yi-chong, CHEN Gui-lian, GAO Yuan-yuan, ZHAO Tong, YU Guang, LAN Shan-hong, Lü Xiao-mei
DNA methylation patterns which associated with normal tissue development and disease initiation could be affected by environmental contaminants and related toxicity. For the requirement of quantification low abundant of 5-methyl-2’-deoxycytidine (5-mdC) in the genome of ecologically relevant species, a label-free and accurate method using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was developed and validated. The global DNA methylation calculation formula of 5-mdC(mole)/(5-mdC(mole)+dC(mole)) could be transformed as 1/(1+dC(mole)/5-mdC(mole)), then the molar ratio of 5-mdC and dC (dC(mole)/5-mdC(mole)) in DNA samples was obtained by HPLC-MS/MS. The important features of the provided method are as follows: (1) avoiding the usage of expensive stable isotope labeled internal standards; (2) isocratic separating normal and modified nucleosides and eliminating cross-interferences of analytes; (3) providing data with high accuracy even detecting low levels of methylated DNA samples. The limits of quantification for 5-mdC and dC were 40 and 60pg/mL, respectively. The intra-day and inter-day relative standard deviations (≤10%) and accuracy (relative errors) were satisfactory. The results obtained from the analysis of calf thymus DNA and genomic DNA from Daphnia magna and elegans demonstrated the feasibility of the new developed method in evaluation of the potential epigenetic risk of environmental pollutions on ecologically relevant species.
2022 Vol. 42 (7): 3385-3391 [Abstract] ( 130 ) [HTML 1KB] [ PDF 431KB] ( 513 )
3392 Community characteristics of soil macrofauna and its influencing factors at Rating Forest
WANG Zhuang-zhuang, LI Tian-shun, ZHU Shi-ying, HUANG Qian, HE Kai, SUO Nan-cuo, PU Bu
The spatial distribution characteristics of soil macrofauna communities and their relationship with environmental factors were analysed with 9 plots. The soil samples were set up at three elevation zones according to the geographical features in July 2021. The soil macrofauna were collected by hand and stored in 75% alcohol, and the influencing environmental variables were recorded at the same time. A total of 1427 soil macrofauna were captured belonging to 21 families, 15orders, 5 classes and 2 phyla. Among them, the dominant groups were Julidae and Formicidae, accounting for 66.0% of the total soil macrofauna. There were 10 common taxa accounting for 31.3% of the total number of soil macrofauna, and 2.7% of rare taxa. There were no significant differences in the number of group, Shannon diversity index, evenness index and dominance index of the soil macrofauna between three different elevation zones (P>0.05). The Jaccard similarity coefficient ranged from 0.15 to 0.77 of soil macrofauna communities. The number of soil macrofauna was negatively correlated with altitude (P<0.01) and positively correlated with soil temperature and pH (P<0.05) significantly. Redundancy analysis (RDA) showed that RDA axis 1and axis 2 explained 55.0% of the accumulative variation in soil macrofauna group composition. Total phosphorus and available phosphorus were significant explanatory variables, accounting for 29.6% and 18.5% of the variation in soil macrofauna communities, respectively.
2022 Vol. 42 (7): 3392-3402 [Abstract] ( 110 ) [HTML 1KB] [ PDF 1291KB] ( 375 )
Carbon Emission Control
3403 Carbon emission from coastal container ports in China based on AIS data
CHEN Wei-jie, SONG Bing-liang, ZHANG Jie-shu
A calculation framework of port carbon emission was proposed to accurately and effectively measure the carbon emission of ships in port, and the carbon emission capacities of ports were analyzed based on massive ship AIS (automatic identification system) navigation trajectory data and the operating data of listed port companies. Taking the AIS trajectory data of 4,280 container ships in 2018 as an example, we achieved several results in calculating the social cost of carbon emissions of the 11major coastal container ports in China. First of all, the result revealed that the carbon emissions of China's coastal container ports were overall positively correlated with the number of ships arriving at the port. For example, Shanghai port was the world's largest container port in 2018, which also suffered the highest carbon dioxide emissions of 693,000 tons. Secondly, the proportion of carbon dioxide emissions of ships in berthing and anchoring was relatively high, accounting for 65.8% of carbon emissions in port. Thirdly, the social cost of carbon emission from ships in the Shanghai port area was the highest, reaching 24.596million yuan in total. But in terms of the capacity to bear the social cost of carbon emission, Lianyungang was under tremendous pressure, expending 244,600 yuan on the social cost of carbon emission for every 100million operating incomes.
2022 Vol. 42 (7): 3403-3411 [Abstract] ( 394 ) [HTML 1KB] [ PDF 614KB] ( 1294 )
3412 Medium- and long-term carbon emission forecast and technological emission reduction potential analysis of China's civil aviation industry
XU Ji-hui, WANG Ke
This study develops a bottom-up energy system model of China's civil aviation industry based on the LEAP model framework, sets FROZEN, GOAL, MAX, SAF, and REVOLUTION scenarios to quantitatively analyze the industry’s driving factors and development trends, and discusses the medium- and long-term low-carbon development technological pathways. The results show that the number of flights per person is expected to quadruple to more than two by 2060, which will imply up to 690million tons of carbon emissions under the FROZEN (baseline) scenario. Under the MAX scenario, carbon emissions from China’s civil aviation industry are expected to reach a peak at around 300million tons in 2044. The cumulative emission reduction of nearly 50% over the 40 years only requires an additional cost of about 1trillion RMB (compared to the baseline). Promoting fleet replacement, accelerating infrastructure upgrading and operation improvement, and developing sustainable aviation fuels are the essential emission reduction means for the civil aviation industry, which can bring 44.1%, 29.5%, and 26.4% emission reduction respectively. In conclusion, China’s civil aviation industry should formulate the goal of "carbon peak and carbon neutrality" and its implementation plans as soon as possible: promoting the airspace reform, air traffic management, and refined airline management in the short- and medium-term, providing vigorous support to the development of domestic large aircraft, and accelerating the commercialization and marketization of industry chain of sustainable aviation fuels in the long term.
2022 Vol. 42 (7): 3412-3424 [Abstract] ( 215 ) [HTML 1KB] [ PDF 695KB] ( 1355 )
Environmental Microbiology
3425 Effects of earthworms on the antibiotic resistance genes of vermicompost from dewatered sludge revealed by active microbes
WEI Feng-yi, XU Jun-jie, CHEN Jin, LI Jian-hui, HUANG Kui, DONG Xi-lin, XIA Hui
To eliminate the abundances of ARGs in sludge vermicompost, this study aimed to reveal the underlying effects of earthworms on the active bacterial community structure and their ARGs involved in vermicomposting systems for sludge recycling. For this, vermicomposting with and without earthworms was set up in parallel. Moreover, the dyeing pretreatment for samples with propidium monoazide (PMA) was adopted to screen out the DNA of active bacteria. The results showed that the electrical conductivity of sludge vermicompost was significantly increased by 82.5% (P<0.05), the degradation rate of organic matter was increased by 5.2% (P<0.05). Compared with the control treatment, the abundance of Actinobacteria significantly increased by 65.6% (P<0.05), while the abundance of Firmicutes and Bacteroidetes significantly decreased by 74.7% and 34.6%, respectively. Meanwhile, vermicomposting led to the selected ARGs abundances of tetM, sul1, sul2, ermB and ermF significantly decreased by 66.5%, 82.8%, 72.8% and 77.6% (P<0.05), while the abundance of ermB significantly increased by 5.7times (P<0.05) in active bacteria, compared to the counterpart. The abundance of intI1gene in vermicompost products significantly reduced by 67.2% compared with the control treatment. The total absolute abundance of ARGs was 4.19×1013 copies/g, and the total removal rate of ARGs was 82.6%, 45.4% higher than that of the counterpart. This study suggests that earthworms can reduce the abundance of dominant hosts of ARGs by modifying the active microbial community structure of sludge, thus reducing the associated dissemination risks of the spread of ARGs.
2022 Vol. 42 (7): 3425-3433 [Abstract] ( 126 ) [HTML 1KB] [ PDF 546KB] ( 290 )
3434 Survival and aggregation characteristics of bacteriophage MS2 in anaerobic water environment and influence of physicochemical factors
ZHANG Chong-miao, ZHAO Qian, WANG Zhen
Bacteriophage MS2 was chosen as the model virus to reveal the survival characteristics of virus in anaerobic water environment. The effect of physicochemical conditions, including temperature, pH, suspended particles, and acetic acid on bacteriophage MS2 were studied by double-layer plate method. The decay kinetics of bacteriophage MS2 were analyzed, and the aggregation of phage particles under different conditions was investigated by measuring Zeta potential and plaque diameter. The results showed that the decay of bacteriophage MS2 in anaerobic water environment followed the first-order exponential decay model. Among the above-mentioned factors, temperature was the most important factor affecting the survival of bacteriophage MS2. At 4℃, 17℃, 25℃ and 35℃, the T90 values of bacteriophage MS2 were 20.36d, 6.14d, 5.15d and 0.46d, respectively. The inactivation rate of bacteriophage MS2 was as high as 2.44lg after 12h at 35℃, while the inactivation rate was only 0.78lg after 7days at 4℃. Increasing the concentration of acetic acid significantly enhanced the inactivation rate of bacteriophage MS2. Low pH value and suspended particles promoted the aggregation of bacteriophage MS2, which caused Zeta potential decrease and the hydrodynamic diameter of phage particles increase, but excessively high concentrations of suspended particles affected the electrostatic interaction between particles. The aggregation of bacteriophage MS2 also increased the diameter of plaques. Under the condition of pH 6 and suspended particles at 20mg/L, the proportion of large plaques with diameter more than 1.0mm reached 45.61% and 57.74%, respectively. Clarification of the impact of various physicochemical factors on bacteriophage MS2 in anaerobic water environment can provide scientific basis for virus control in water environment.
2022 Vol. 42 (7): 3434-3442 [Abstract] ( 125 ) [HTML 1KB] [ PDF 1549KB] ( 277 )
3443 Study of minor 2-EH surfactant on promoting LiCl liquid desiccant to inactivate mold in air-conditioning systems
LI Rui-qing, YANG Zi-li, GU Yu-qian, YOU Yu-xin, LING Chen, ZHANG Min-xin
Effects of minor 2-EH (2-ethyl-1-hexanol) surfactant on improving the inactivation ability of LiCl liquid desiccant on two species of resistant mold spores in air conditioning systems, A. niger and P. citrinum were studied. The results showed that minor addition of 2-EH (50×10-6~300×10-6) substantially enhanced the mold inactivation performance of LiCl liquid desiccant with an efficiency improvement of 12.6 fold. By adding only 300×10-6 of 2-EH, the A. niger spores were effectively inactivated (with efficacy of around 100%) by the dilute LiCl aqueous solution (20% mass concentration) instead of the concentrated 40% LiCl solution. The improvement was particularly significant for the dilute LiCl solution, which considerably reduced the essential solution concentration for effective mold inactivation. SEM analysis showed that the addition of minor 2-EH accelerates the cell structure damage and collapse of the mold spores exposed in the LiCl solution. The results may significantly improve the mold inactivation performance of the LiCl liquid desiccant air-conditioning system and reduce the risks of mold aerosol transmission.
2022 Vol. 42 (7): 3443-3449 [Abstract] ( 139 ) [HTML 1KB] [ PDF 2052KB] ( 284 )
Environmental Toxicology and Health
3450 Effects of short-term exposure to PM2.5 and PM10 on blood pressure in adults in Jinchang City
ZHANG Li, SHI Guo-xiu, LIU Yan-li, WANG Min-zhen, ZHANG Xiao-fei, Lü Kang, KANG Feng, BAI Ya-na, ZHENG Shan
In order to explore the effect of short-term exposure to particulate matter (PM) on blood pressure (BP) level in northwest China, based on the Jinchang cohort platform, the data on the particulate pollution of Jinchang City and BP measurement of cohort population from 2011 to 2017 were collected. After adjusting for relevant confounding factors, a linear mixed-effect model was used to analyze the effects of short-term exposure to PM2.5 and PM10 on systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), Pulse pressure (PP) and Mid-BP (the mean of SBP and DBP). The results showed that with the increase of PM2.5 concentration, the levels of SBP, MAP, PP and Mid-BP all showed an upward trend, and their largest effects were found at the cumulative lag 05, 03, 07 and 05 days, respectively. With the increase of PM10 concentration, the five BP indicators all showed an upward trend, and their largest effects all appeared at cumulative lag 07 days. The effect of PM2.5 and PM10 on BP were more significant in smoker and male. In addition, dust weather and gaseous pollutants (SO2 and NO2) had a certain effect modification on the PM-BP effect. Therefore, there was an adverse effect of short-term exposure to PM2.5 and PM10 on people’s BP, smokers and males may be susceptible to the effect of PM on BP.
2022 Vol. 42 (7): 3450-3460 [Abstract] ( 134 ) [HTML 1KB] [ PDF 877KB] ( 276 )
Biodiversity
3461 Survival status and protection effectiveness of Paphiopedilum Subgenus. Brachypetalum in China
ZHANG Yang, AN MingTai, WU Jian-Yong, YANG Yan-Bing, LI Zhi, YE Chao
In order to clarify the survival and endangered status of Paphiopedilum subgenus Brachypetalum in China, the population distribution, quantity, habitat characteristics, market trade, threatened factors, protection status and effectiveness of this group were statistically analyzed, based on a large number of field investigations, references and specimens data. And the endangered grade of this group was reassessed according to the IUCN Red List Categories and Criteria (version 3.1). The results showed that P. micranthum, P. malipoense, P. armeniacum, P. emersonii, P. bellatulum, P. wenshanense and P. concolor had been found in the field investigation. And the seven Subgenera were known to be distributed in 50 counties in China, with a total of 194 natural distribution points. In the horizontal direction of China, Subgenus Brachypetalum were mainly distributed in Southeast and Northwest of Yunnan, Southwest and Northeast of Guizhou, Northwest and Southwest of Guangxi and the junction of Northern Guangxi and Southern Guizhou. In the vertical direction, the Subgenus mainly distributed in the middle-high elevation area (780~1267m), with an average altitude of 997m. On a national scale, the Subgenus were scattered distribution, and the individuals grew in aggregation on the small scale. Their microhabitats were characterized by high altitude, permeable, breathable, shady and high calcium. The market trade rate of Subgenus Brachypetalum was 36.67%, and the trade price had strong randomness; the trade source mainly depended on the extraction of wild resources which accounting for 88.32% of the trade volume, with strong regional characteristics; the trade mode was on-site and online with strong flexibility. This group was mainly threatened by excavation and habitats degradation, accounting for 44.85% and 29.83% of all distribution points respectively. The in-situ protection rate of Subgenus Brachypetalum was only 34.53%, which was general protection effectiveness; The group had been protected 98 times in 20 conservation sites, among the 29conservation sites which were investigated. Except for P. wenshanense and P. hangianum, the ex-situ protection effects of the other 7 species were evaluated as appropriate. P. bellatulum and P. wenshanense were assessed as critically endangered (CR) from the original endangered (EN); no change was happened in the assessment of P. malipoense, P. emersonii and P. armeniacum, they were still belong to critically endangered (CR); P. micranthum and P. concolor were assessed as endangered (EN) from the original vulnerable (VU); P. delenatii and P. hangianum were rated as data deficiency (DD).
2022 Vol. 42 (7): 3461-3472 [Abstract] ( 136 ) [HTML 1KB] [ PDF 1331KB] ( 348 )
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