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  Current Issue
 
2022 Vol.42 Issue.8,Published 2022-08-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Ecology
Environmental Toxicology and Health
Carbon Emission Control
Air Pollution Control
3473 Source profile characteristics of industrial VOCs in Shenzhen from the perspective of PM2.5 and O3 synergistic control
HUANG Pei-rong, ZHU Bo, ZHANG Yue, HUANG Xiao-feng, ZHU Qiao, YU Guang-he, YAN Min, LIANG Yong-xian, HE Ling-yan
100 VOCs components of samples were detected taken from 8 typical industries in Shenzhen so as to characterize different sources and analyze their impacts on PM2.5 and ozone pollution. The results show that, of all emissions from gas stations, alkanes accounted for 48.4%, followed by oxygenated VOCs (27.6%), ethyl acetate (14.1%), isopentane (13.0%), and n-pentane (12.0%). While oxygenated VOCs were mainly emitted from manufacture of coating, adhesives, ink, chemicals, textile printing and dyeing agents, pharmaceutical products, etc., accounting for 42.3%~97.1% of all VOCs. Furthermore, acetone was dominantly emitted from most industries and acetonitrile from some industries. For waste-to-energy industry, oxygenated VOCs and halogenated hydrocarbons contributed 33.9% and 28.3%, respectively, followed by acetaldehyde (13.4%), acetone (11.0%) and chloromethane (6.1%). For synergistically controlling PM2.5 and ozone, aromatic hydrocarbons and olefins generated from storage and transportation are the primary compounds to be mitigated; and oxygenated VOCs and aromatic hydrocarbons are the key components to be controlled in processing industry and waste disposal. Because of high SRO3 (6.0g/g) and SRSOA (1.2g/g) in coating manufacture, to most effectively mitigate PM2.5 and ozone by reducing per unit of VOCs emissions should become the priority for synergistically controlling PM2.5 and ozone in Shenzhen.
2022 Vol. 42 (8): 3473-3482 [Abstract] ( 173 ) [HTML 1KB] [ PDF 1750KB] ( 374 )
3483 Changes in optical properties and chemical functional groups of humic substances emitted from biomass combustion with O3 oxidation
CAO Tao, SONG Jian-zhong, FAN Xing-jun
Biomass combustion (BC) is an important source of humic-like substances (HULIS) in atmospheric aerosol, and the oxidation process has a significant impact on the optical properties and chemical structures of BC-HULIS. This study focused on the changes in primary BB-HULIS due to ozone (O3) oxidation and the optical properties and chemical structure of HULIS before and after oxidation were characterized with the total organic carbon (TOC) analyzer, UV-Vis spectroscopy, Excitation-Emission Matrix coupled with parallel factor analysis (EEM-PARAFAC) and Fourier transform infrared spectroscopy (FTIR). The results showed that the relative contents of HULIS in the corresponding water-soluble organic carbon (WSOC) decreased with O3 oxidation, suggesting the transformation of HULIS into water-soluble low molecular weight compounds. Furthermore, mass absorption efficiency (MAE365) and aromatic index (SUVA254) of HULIS decreased from 1.8~2.7m2/gC and 4.2~5.0m2/gC to 1.1~1.3m2/gC and 3.7~4.1m2/gC, respectively, indicating that both the absorption capacity and aromaticity of HULIS declined with O3 oxidation. The fluorescent components in BC-HULIS were mainly composed of protein-like compounds (C2) and humic-like substances (C1, C3, C4). After O3 oxidation, the total fluorescence intensities of BC-HULIS weakened greatly, and the relative contribution of two types of fluorophores and fluorescence index were all significantly changed. For instances, the relative contents of humic-like components and the humidification index (HIX) of BC-HULIS after O3 oxidation were obviously higher than those before O3 oxidation, suggesting the degradation of protein-like compounds and the aggregation of humic-like substances during the O3 oxidation process. In addition, FTIR results showed that the oxygen-containing functional groups were markedly enhanced after O3 oxidation, indicating effects of O3 oxidation on the chemical functional groups of BC-HULIS.
2022 Vol. 42 (8): 3483-3491 [Abstract] ( 139 ) [HTML 1KB] [ PDF 782KB] ( 269 )
3492 Long-term trends of tropospheric NO2 over the Fenwei Plain of China based on OMI data
CHEN Ling, YAN Shi-ming, NI Cheng-cheng, ZHU Ling-yun, XIAO Hui, WANG Yan, WANG Wen-ya, HE Jie-ying, GUO Wei
This study explored the long-term trends of NO2 tropospheric vertical column density (NO2 TVCD) and its responses to NOx emissions, as well as their impacts on the lower tropospheric O3 over the Fenwei Plain of China. The long-term observations from 2007 to 2020 used here consist of:NO2 TVCD data of Ozone Monitoring Instrument (OMI) OMNO2d, NOx emissions of European Quality Assurance for Essential Climate Variables project (QA4ECV) products by Daily Emission estimation Constrained by Satellite Observations (DECSO) algorithm, and ozone (O3) vertical profile data of Atmospheric Infrared Sounder instrument (AIRS) AIRS2SUP. The results showed that:(1) NO2 TVCD peaked at (9.8±4.6)×1015molec/cm2 in 2012, then tended to decline generally after 2013; (2) NO2 TVCD was higher by 260% in winter than in summer; (3) The variations in NO2 TVCD were not exactly consistent with the anthropogenic mitigation of NOx emissions but increased in Summer at its lower percentiles with a rate of (-1.5±0.6)%/a (less than a third of the reduction in NOx emissions), which was probably due to the large contribution of natural sources of tropospheric NOx and its increasing relative contribution under the background of massive anthropogenic NOx emissions mitigation; (4) The O3 variability was (-0.2±0.2)%/a in the middle-lower troposphere and (0.8±0.1)%/a in the near surface, indicating that the tropospheric O3 generation in the Fenwei Plain was basically within the VOCs-limited or VOCs-NOx transitional regimes, and the anthropogenic NOx emissions reduction could not reduce the tropospheric O3; (5) The anthropogenic NOx emission reduction could effectively reduce NO2 in urban high emission areas, but in the rural areas where natural NOx sources dominated. Generally, the efficiency of the anthropogenic NOx emissions reduction was not significant over the Fenwei Plain.
2022 Vol. 42 (8): 3492-3501 [Abstract] ( 126 ) [HTML 1KB] [ PDF 3226KB] ( 393 )
3502 Impacts of ammonia and nitrogen oxides emissions on fine particle matter pollution and mitigation potential over the Sichuan Basin
YANG Xian-yu, LYU Ya-qiong, SHAO Ping, PAN Yue-peng, FAN Jin, WANG Shi-gong, ZHANG Xiao-ling, YI Jia-jun, QIAO Yu-hong, WU Kai
In this study, satellite data derived from IASI, OMI and TROPOMI were adopted to infer the trend of ammonia and NOx emissions over 2008~2019 and the weather research forecast model (WRF) and the Community Multiscale Air Quality (CMAQ) were used to assess the environmental consequence of ammonia emissions over the Sichuan Basin in the winter of 2019. Furthermore, sensitivity experiments were performed to evaluate impacts of ammonia or NOx emission reduction and ammonia and nitrogen oxides coordinated emission reduction scenarios on fine particles. The results show that nitrogen oxides emissions increased interannually from 2008 to 2012 and then decreased rapidly from 2013 to 2019, while ammonia columns were relatively stable over 2008~2013 and increased significantly from 2014 onwards. The hotspots of ammonia emissions in the Sichuan Basin were mainly concentrated in southern Sichuan city cluster and Chengdu and surrounding areas where anthropogenic activities were intense. The elevated ammonia emissions were also observed in the northwestern Sichuan city cluster dominated by agricultural sources. Ammonia ions accounted for a relatively high fraction of PM2.5 in southern Sichuan city cluster, up to 11.4%, while its contribution to PM2.5 in the cities of western Sichuan were relatively low. Sensitivity experiments indicate that the coordinated emission regulation in simultaneously reducing 50% NOx and ammonia could effectively diminish the concentrations of ammonium nitrate and ammonium sulfate in PM2.5, therefore reduce fine particulate pollution and improve the regional ambient air quality across the Sichuan Basin.
2022 Vol. 42 (8): 3502-3511 [Abstract] ( 182 ) [HTML 1KB] [ PDF 6335KB] ( 326 )
3512 Quantitative analysis of the impact of anthropogenic emissions and meteorological factors on air quality: Cases during the epidemic in Xingtai City
QI Hao-yun, WANG Xiao-qi, CHENG Shui-yuan
Meteorological and human factors during the specific epidemic are critical for effectively evaluating the causes of air quality changes in different areas. This study selected Xingtai City, Hebei Province as the research object, took 2020 epidemic situation as an experimental scenario of extreme emission reduction under the extreme control measures, and 2021 epidemic situation as an experimental analysis scenario of future normalized epidemic prevention and control. Compared with the period prior to the epidemic, the ozone concentration during the two epidemics increased, and the particle concentration during the 2021 epidemic also increased. The concentration of other pollutants during the 2020 epidemic decreased to varying degrees. Compared with the same period in 2019, the ozone concentration during the two epidemics also increased. In addition, the pollutant concentration during the 2021 epidemic declined more. Using LSTM algorithm and WRF-CMAQ model to quantify impacts of meteorological factors on the changes in pollutant concentration during the two epidemic periods. The human-induced changes in different pollutant concentrations were deduced as indicated by the results from the air quality simulation. The simulation of LSTM algorithm during the two outbreaks shows that human being had a negative impact on pollutants (reducing their concentration) and accounted for a high proportion in the total change, while the influence of meteorological factors simulated with CMAQ model was much higher than that with LSTM algorithm. Anthropogenic influences dominated during the 2020 epidemic period, while compared to that during the 2020 epidemic period, the impact of anthropogenic activities on pollutants (except NO2) was positive (promoting an increase in pollutant concentration) during the 2021 epidemic period.
2022 Vol. 42 (8): 3512-3521 [Abstract] ( 214 ) [HTML 1KB] [ PDF 1336KB] ( 363 )
3522 Physicochemical characteristics and sources of atmospheric submicro particulate matter at a typical area in Beijing
HAN Li-hui, SHI Rui-fang, CUI Jian-shuo, YANG Xue-mei, WANG Hai-yan, CHENG Shui-yuan
An Aerodyne Aerosol Chemical Speciation Monitor ACSM was deployed to continuously monitor the concentrations of non-refractory submicron particulate matter NR-PM1 and its species in March, August, October and December representing spring, late summer, autumn, and winter, respectively, in the southeast urban area of Beijing. The evolution characteristics of NR-PM1 and its species in different periods, especially during the haze days, and the sources of organic aerosol OA in the four seasons were investigated. The results showed that the average concentration of NR-PM1 was 22.06μg/m3 in the whole study period. The seasonal variation of NR-PM1 mass concentrations followed the order of spring > winter > autumn > late summer. In the study period, the average concentration of Org was 7.12μg/m3, accounting for 32.30% of NR-PM1; the average concentrations of NO3- and SO42- were 5.91 and 6.20μg/m3, respectively, accounting for 26.80% and 28.12% of NR-PM1 respectively; however, the average mass concentrations and mass fractions of both NH4+ and Cl- were lower. All species concentrations showed the order of Org > SO42-~NO3-> NH4+> Cl-. NR-PM1 in clean days was mainly characterized by Org, and the diurnal variations of all species in each season were smaller. However, NR-PM1 in haze days was mainly characterized by secondary inorganic species, and each species showed different diurnal variations in different seasons. OA species apportioned in different seasons were slightly different. The contributions of primary OA (POA) to OA gradually increased in the order of spring < late summer < autumn < winter, but secondary OA (SOA) to OA gradually decreased.
2022 Vol. 42 (8): 3522-3535 [Abstract] ( 150 ) [HTML 1KB] [ PDF 1161KB] ( 252 )
3536 Coupling effect of Fe-based catalyst on coal pyrolysis-combustion NOx control
YANG Song, KONG Xiang-lu, WANG Qi, LI Jiang-peng, JIAO Ting-ting, ZHANG Kai-xia, LIU Shou-jun, SHANG Guan-Ju
In order to solve the problem of NOx emission in civil loose-burning raw coal, a source control strategy of "pyrolysis to reduce nitrogen and couple combustion to denitrate" was put forward to realize pollutant emission. The additive was introduced into raw coal in one step to control NOx emission in the process of pyrolysis and combustion. The specific research contents were as follows:coal and iron additive were pyrolyzed in a tube furnace to prepare clean fuel, The emission of NOx during clean fuel combustion was studied. The influence of iron additives on nitrogen migration and the influence of surface structure and pore structure of clean coke were systematically investigated. The results showed that iron additives loaded before pyrolysis existed stably in coke and promoted the transformation of nitrogen-containing compounds into N2 during pyrolysis. In the combustion process of clean coke, the existence of iron additives is beneficial to the catalytic reduction of NOx by C and CO, and then the emission of NOx in the combustion process is controlled. The iron additives introduced in one step play a coupling effect of NOx control in the coal pyrolysis-combustion process, realizing the ultra-low emission of NOx.
2022 Vol. 42 (8): 3536-3543 [Abstract] ( 116 ) [HTML 1KB] [ PDF 954KB] ( 226 )
3544 Driving factors and spatio-temporal distribution on NO2 and CO2 in the Yangtze River Delta
HE Yue, SHENG Meng-ya, LEI Li-ping, GUO Kai-yuan, HE Zhong-hua, CAI Ju-zhen, FANG He, ZHANG Xiao-wei, LIU Ying, ZHANG Yu-hui
In this paper, with the Yangtze River Delta urban agglomerations as the study area, the satellite remote sensing data were used to carry out collaborative analysis on the temporal and spatial variations of atmospheric NO2 and CO2 concentrations and the driving factors, which revealed the areas with high concentrations of air pollution and CO2. The results indicated that the spatio-temporal distributions of NO2 and CO2 and its changing characteristics in the Yangtze River Delta urban agglomeration areas were subjected to the combined effects of human activities such as fossil fuel combustion and vehicle emissions, as well as natural conditions such as regional topography, regional topography, surface coverage and climate. The areas with high concentrations of atmospheric NO2 and CO2 were in an U-shaped distribution towards the southwest direction around Taihu Lake, which was consistent with the distribution of the surrounding large urban areas and the industrial emission areas. Featured with seasonal distribution characteristics, the atmospheric NO2 concentrations were higher in autumn and winter, and the lowest in summer. Affected by vegetation CO2 uptake and CO2 emission accumulation, atmospheric CO2 concentrations were the lowest in August-September and the highest in April-May. In addition, with the sharp reduction in anthropogenic emission activities from January to March 2020, NO2 concentrations were reduced by more than 50% compared with the same period in 2019 and dropped the most in cities with large-scale ferrous-metal and coal-processing industrial heat sources.
2022 Vol. 42 (8): 3544-3553 [Abstract] ( 225 ) [HTML 1KB] [ PDF 4234KB] ( 451 )
3554 Risk assessment of PM2.5 pollution based on machine learning and nonparametric estimation
ZHOU Qi, YU Yang, LIU Miao-miao, BI Jun
A systematic approach of regional PM2.5 risk and characterization assessment was developed in this study by integrating random forest model, Quantile-Quantile plot model, and K-mean model, based on multi-source data including mobile phone signals, meteorological data, geographic data, etc. This new approach was further applied in a case study of Nanjing at a 0.3km resolution grid. On the one hand, this new approach effectively simulated the temporal and spatial distribution of the PM2.5 concentration with an10-fold cross-validation R2 of 0.76 and screened out four major pollution characteristics. On the other hand, it effectively captured the short-term population mobility risk. Short-term population mobility increased the PM2.5 exposure risk by 0.30~0.97 times, even keeping PM2.5 concentration unchanged. After combining PM2.5 concentration and population mobility simultaneously, four major PM2.5 exposure risk modes were identified. 6.5% of the areas of Nanjing were at high risk, and 23.0% were at low risk. During the 14th Five Year Plan, it is suggested that the government should speed up the application of modern science and technology in environmental protection and implement gridding and differentiated policies on air pollution risk control to promote human health.
2022 Vol. 42 (8): 3554-3560 [Abstract] ( 144 ) [HTML 1KB] [ PDF 3508KB] ( 310 )
3561 Pollution characteristics and potential pollution source regions of atmospheric OPAHs in Lanzhou
LI Hong-yu, LI Pei-qi, HUANG Juan, YANG Zhao-li, LIU Peng, ZHANG Li-yuan, MA Hai-bo, MAO Xiao-xuan, GAO Hong, HUANG Tao
A field campaign was conducted to monitor oxygenated polycyclic aromatic hydrocarbons (OPAHs) concentrations in gas phase and particulate matter (PM1.0, PM2.5 and PM10) in a winter week (December 1st~7th, 2016) and a summer week (August 3rd, 2017) across the Lanzhou City. The results showed that total gaseous + particulate concentration of Σ8OPAHs ranged from 1.83 to 19.28ng/m3 with a mean of (6.45 ±3.43) ng/m3. The atmospheric Σ8OPAHs level in the winter week was 2.06 times that in the summer week. Particle-bound OPAHs contributed to a large proportion to both 2.5~10 and <1.0μm size ranges in the winter week, whereas in the summer week, OPAHs were generally detected in PM1.0. 9-Fluorenone (9-FLU), 9,10-Anthraquinone (9,10-ANT) and Benzanthrone (BZA) were the most abundant OPAHs, accounting for 51.8%~94.9% of the total, from which the absorption mechanism was thought to dominate the gas-particle partitioning of sampled OPAHs. The results from a concentration weighted trajectory (CWT) model reveal that the OPAHs concentration in Lanzhou was significantly affected by local emission sources in the winter week, followed by long-distance atmospheric transport from the northwest of Lanzhou, covering the part of Xinjiang and Qinghai Provinces. In the summer week, the OPAHs mainly presented in the southeast of Lanzhou, such as Dingxi and Tianshui and the northeast, such as Zhongwei in Ningxia Hui Autonomous Region.
2022 Vol. 42 (8): 3561-3571 [Abstract] ( 137 ) [HTML 1KB] [ PDF 7487KB] ( 289 )
3572 Studies on background concentration and source-sink characteristics of CO2 in Wutai Mountain
LI Ying, YAN Shi-ming, WANG Shu-min, ZHANG Feng-sheng, YU Xiao-hong, YANG Ai-qin, YUE Jiang, JIN Ze-hui
Based on the continuous CO2 datasets from 2017 to 2020, observed at Wutaishan GHG station, the background concentration and source-sink characteristics of CO2 in Wutai Mountain were studied by using the Moving Average Filtering (MAF) method and backward trajectory analysis. The results show that the atmospheric CO2 concentrations were affected by regional or local sources/sinks, with the smaller hourly amplitude of background concentration (44.9×10-6), compared to that of unselected CO2 concentration (94.7×10-6). The CO2 background concentration had slowly increased from 2017 to 2020. Particularly, the proportion of rising concentration had decreased probably due to the weakened human activities. On the contrast, the variation in the absorption concentration was stable, inferring that the effect of terrestrial ecosystem on CO2 concentration was relatively stable. The seasonal mean of CO2 background concentration was the lowest in summer, secondly in autumn and winter, and the highest in spring. The diurnal variation in CO2 background concentration was most obvious in summer, with the peak and valley value around 5:00a.m. and 16:00p.m., respectively; the diurnal variation fluctuated slightly in other seasons with amplitudes merely between 0.7×10-6 and 1.8×10-6. Compared to the background concentration, the CO2 uplifting concentration differed remarkably from October to March, whereas the change in absorption concentration occurred from June to September, indicating impacts of anthropogenic emission and terrestrial ecosystem carbon absorption on CO2 concentration. The diurnal variation in source-sink concentrations displayed a single peak structure, and the rising concentration was high during the day and low at night, and the reversion was just for the absorption concentration. In spring, autumn and winter, the southwest wind was mainly responsible for the significant CO2 uplift, and CO2 concentration could stay at a high level with an increase in wind speed; while, in summer,the northeast easterly wind obviously enhanced the observed values. Besides, in spring and summer, the wind speed between 2 and 4m/s was conducive to reduce the CO2 absorption concentration. Evidently, the impact of long-range transport of air masses on the source-sink concentrations depend not only on the source strength of CO2 in the pathway, but also on the spatial vertical transport path of the air masses.
2022 Vol. 42 (8): 3572-3583 [Abstract] ( 87 ) [HTML 1KB] [ PDF 4071KB] ( 275 )
3584 Evaluation of odor annoyance from wastewater treatment plant with air dispersion model and its validation
WANG Wen-mei, ZHANG Yan, JING Bo-yu, ZHANG Zhi-yang, YANG Wei-hua, GENG jing
The odor emission sources were sampled from a wastewater treatment plant, and the odor annoyances were simulated by air dispersion model and validated through plant boundary monitoring, on-site sniffing monitoring and questionnaire survey. The results showed that the separation distances of the wastewater treatment plant were 200~1450m around all directions and its eight surrounding residential areas were detected to have odor annoyance. The results simulated with air dispersion model have good consistency with those from monitoring results and residents' evaluation. This study can provide technical support for standardization of odor pollution evaluation method and odor impact criterion in China.
2022 Vol. 42 (8): 3584-3590 [Abstract] ( 108 ) [HTML 1KB] [ PDF 700KB] ( 245 )
3591 Chemical composition characteristics and source of non-refractory submicron aerosol in autumn and winter in the northern suburbs of Nanjing
YE Nan, MA yan, JIANG You-lin, ZHENG Jun
In this study, Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to monitor the chemical components (including organic matter, nitrate, sulfate, ammonium and chloride) and characteristics of non-refractory submicron aerosol (NR-PM1) in autumn and winter in the northern suburbs of Nanjing, and PMF & ME-2 (positive matrix factorization & multilinear engine) source analysis mode was used to identify sources of complex organic compounds. During the observation period, the contributions of organic matter, nitrate, sulfate, ammonium and chloride to NR-PM1 were 42%, 28%, 15%, 13% and 2% respectively. Six types of organic aerosols were identified:hydrocarbon like organic aerosol (HOA), cooking related organic aerosol (COA), biomass burning organic aerosol (BBOA), more oxidized organic aerosol (MO-OOA), less-oxidized oxygenated organic aerosol (LO-OOA) and aqueous-phase-processed oxygenated organic aerosol (aq-OOA), and their average concentrations accounted for 18%, 14%, 19%, 19%, 11% and 19% of the total organic aerosols, respectively. The results of comparing different pollution events show that the proportion of secondary aerosol will increase significantly during the pollution period, and the liquid phase reaction can significantly promote the formation of secondary components.
2022 Vol. 42 (8): 3591-3599 [Abstract] ( 125 ) [HTML 1KB] [ PDF 2644KB] ( 222 )
3600 Molecular simulation study on the anti-As2O3 poisoning ability of γ-Fe2O3
ZHOU Wen-bo, NIU Sheng-li, LIU Si-tong, WANG Dong, HAN Kui-hua, WANG Yong-zheng
The γ-Fe2O3 catalyst, due to its advantages in low cost and high catalytic performance, is thought to be a promising medium-low temperature SCR catalyst, but the As2O3 in the flue gas likely becomes seriously deactivated. In this study, the density functional theory was used to characterize the adsorption of As2O3 on the γ-Fe2O3 surface as well as the mechanism of doping modification to improve the anti-As2O3 poisoning performance. The adsorption properties of As2O3 on the intact and O-deficient γ-Fe2O3(001) surfaces were examined, including adsorption site, adsorption structure, adsorption energy, PDOS, etc. At the same time, the catalyst model of γ-Fe2O3 doped with Mo, Ti, and Mg was established to understand the mechanism of doping additives on improving the resistance to arsenic poisoning. The results show that the As2O3 tends to be chemically adsorbed on Feoct sites on the γ-Fe2O3(001) surface with the O-terminus, and strong interaction and electron transfer occur during the adsorption process. When there are O defects on the surface, the adsorption energy of As2O3 molecules increases. Mo, Ti, and Mg tend to be doped in Feoct sites, which thus enhances the adsorption capacity of As2O3. Increasing the doping amount of Mo can promote the adsorption of As2O3. As2O3 tends to react with the more active Mo, Ti, and Mg, thereby protecting the active Fe sites from arsenic poisoning. The doping of Ti and Mg also inhibits the adsorption of As2O3 on adjacent Fe sites. The doping of Mo, Ti, and Mg also promotes the adsorption of NH3 on the catalyst surface and elevates the acidity of the surface, which is beneficial to the SCR reaction and to improving the anti-arsenic poisoning performance of the γ-Fe2O3 catalyst.
2022 Vol. 42 (8): 3600-3609 [Abstract] ( 106 ) [HTML 1KB] [ PDF 4882KB] ( 265 )
3610 Characteristics of VOCs emissions from edible vegetable oil processing
SUN Xi-bo, LIANG Xiao-ming, LIAO Cheng-hao, ZHANG Yong-bo, YE Dai-qi
In this study, the VOCs emission factor, composition spectrum and ozone generation contribution of rapeseed vegetable oil and soybean vegetable oil processing industries were studied, and the national VOCs emissions of the industry were also calculated. Results show that the processing VOCs emission factor was 1.20kg per ton of rapeseed, 6.32kg per ton of rapeseed oil, 0.36kg per ton of soybeans, and 2.35g per ton of soybean vegetable oil. The VOCs species emitted from rapeseed oil processing and soybean oil processing were mainly from the volatilization of organic solvents. The VOCs species with the largest proportion of VOCs emissions were n-hexane, followed by methylpentane (including 3-methylpentane and 2-methylpentane), and then methylcyclopentane. The OFP in the vegetable oil processing industry was 931.47μg/m3, of which alkanes contributed 61.90%, followed by olefins (19.61%) and OVOCs (15.14%). In 2019, the total VOCs emissions from China's soybean and rapeseed edible vegetable oil processing were 51200 tons, contributing 65.4% and 34.6%, respectively. Of the total emission, 72% came from Shandong, Hubei, Jiangsu, Guangdong, Henan, Guangxi, Tianjin, Hebei, Hunan, and Fujian together.
2022 Vol. 42 (8): 3610-3615 [Abstract] ( 142 ) [HTML 1KB] [ PDF 424KB] ( 293 )
3616 Characteristics and sources of volatile organic compounds (VOCs) in winter over Nanning of China
LU Jia-hui, WU Ying, LIU Hui-lin, MO Zhao-yu, REN Quan-ming, HUANG Xi-shou, HUANG Jiong-li, YAN Shi-yang, SONG Ling-he
In order to explore the characteristics and sources of volatile organic compounds (VOCs) pollution in winter, an online continuous monitoring system was used to conduct continuous observation of 116 VOCs in Nanning urban area from December 9, 2020 to February 22, 2021. The results show that the total volume fraction of VOCs was 37.57×10-9, of which alkanes, olefins, aromatic hydrocarbons, OVOCs and halogenated hydrocarbons accounted for 44%, 15%, 8%, 19% and 11%, respectively, generally being low in the daytime and high at night. In view of the OH radical loss rate (LOH) and ozone formation potential (OFP), aldehydes and ketones, aromatic hydrocarbons and olefins were thought to be the main active substances. And aromatic hydrocarbons contributed 98% to the generation of secondary organic aerosols (SOA), of which benzene, m/p-xylene and toluene were the dominant species. Then, VOCs mainly derived from the sources in the order as:vehicle exhaust emissions (30.1%) > stationary combustion and biomass combustion (22.2%) > industrial process emissions (16.8%); while the sources with higher OFP contribution were solvent usee (23.9%), stationary- and biomass combustion (22%), and vehicle exhaust emissions (21.8%). Therefore, the priority for controlling VOCs sources in Nanning winter should be firstly placed on the vehicle exhaust emissions and the stationary- and biomass combustion, followed by industrial process emission sources and solvent use sources.
2022 Vol. 42 (8): 3616-3625 [Abstract] ( 127 ) [HTML 1KB] [ PDF 1235KB] ( 229 )
3626 Variations in Ozone pollution and their meteorological influences and transmission sources in Linfen City of China
SONG Xiao-wei, HAO Yong-pei, ZHU Xiao-dong, WANG Jing-wei, XUE Pan, LIU Wei-ting
The spatial and temporal variations in ozone pollution and their relationship with meteorological factors, transmission paths, and potential source distribution in Linfen City were investigated in this study using the potential source contribution function (PSCF) coupled with the hourly ozone mass concentration observations and meteorological data from 2014 to 2020. Results indicate that Linfen City has suffered from increasingly severe ozone pollution in recent years. Overall, the annual average mass concentration of O3_8h_max presented an upward trend, exhibiting a 78.79% increase from 2014 to 2020. Monthly variations featured with an "M"-type double peak, and the seasonal variation peak occurred in summer. Besides, the diurnal variation was significantly affected by the near-surface atmospheric photochemical process, showing a discernible single-peak and single-valley distribution with a peak between 14:00 and 16:00. The O3 concentration demonstrated a significant linear positive correlation with air temperature and hours of sunshine. When the relative humidity was 40%~60%, the temperature was above 20℃, and the wind speed ranged 2~6m/s, the high-concentration O3 pollution would be liable to occur. The transmission mainly relied on short-distance airflow during periods of heavy O3-polluted weather. In this context, in addition to local O3 generation, high O3 concentrations were also affected by the large NOx and VOCs emissions from heavy industries in neighboring cities in Shanxi Province, central Shaanxi Province, and northern Henan Province. Therefore, joint prevention and control measures on the O3 pollution in Linfen City must be adopted throughout the Fenwei Plain area under the premise of strictly controlling the emissions of local pollution sources.
2022 Vol. 42 (8): 3626-3634 [Abstract] ( 147 ) [HTML 1KB] [ PDF 1223KB] ( 395 )
Water Pollution Control
3635 Enhancement of aerobic granular sludge by high-frequency alternating OLR
LI Dong, GAO Fei-yan, XIE Yi-bo, LI Zhu, ZHANG Jie
In this study, four parallel cylindrical sequencing batch reactors, R1, R2, R3 and R4, were operated by constant organic loading rate (OLR) and three alternating OLR modes respectively, fed with synthetic water. Their high and low OLR were 0.67/0.67, 0.71/0.60, 0.77/0.52 and 0.80/0.40gCOD/(L∙d) respectively. The effect of high-frequency alternating OLR on the performance of aerobic granular sludge was explored to provide feasible strategies for improving the stability of aerobic granular sludge. The results showed, the integrity coefficients of R1, R2, R3 and R4 could reach 87.26%, 94.78%, 96.29% and 79.63%, respectively. The EPS content (VSS) of the four reactors were 81.04, 109.46, 115.28 and 139.56mg/g and PN/PS were 4.75, 7.49, 8.28 and 3.26, respectively, indicating that the m value (high OLR/low OLR) of 1.48 was beneficial to improve the structural stability of aerobic granular sludge. In addition, the average COD removal efficiency of R1, R2, R3 and R4in the stable period were 92.58%, 91.52%, 92.45% and 92.52%, respectively. The average TP removal efficiency were 92.81%, 93.35%, 95.10% and 61.01%, respectively. The average TN removal efficiency were 93.04%, 92.24%, 92.06% and 85.32%, respectively, indicating that the aerobic granular sludge had the best effect of removing pollutants when the m value was 1.48.
2022 Vol. 42 (8): 3635-3642 [Abstract] ( 91 ) [HTML 1KB] [ PDF 680KB] ( 206 )
3643 Transport characteristics of PPCPs in the stormwater runoff in a typical livestock breeding farm in Shanghai
LI Mu-yan, SUI Qian, HUANG Shao-xin
The occurrence, temporal variation and first flush effect of 19PPCPs in stormwater runoff in a typical swine farm in Shanghai were investigated. The results show that the concentrations of target PPCPs were in the range of 0.62~166ng/L and 15 out of 19PPCPs exhibited a detection frequency of 100%. The concentrations of target PPCPs peaked in the initial 15~30 minute once the stormwater runoff occurred, then decreased continuously. By using LP-F curve and FF30 which describe the relationship between the pollution load and runoff volume, a significant first flush effect was verified in the stormwater runoff in the swine farm. These findings will provide an important reference for effectively controlling PPCPs pollution in stormwater runoff in livestock farms.
2022 Vol. 42 (8): 3643-3649 [Abstract] ( 105 ) [HTML 1KB] [ PDF 455KB] ( 263 )
3650 Removal of tetracycline hydrochloride from aqueous solutions by sulfonated biochar-activated persulfate
DONG Kang-ni, XIE Geng-xin, YAN Ming, YAN Zhuo-yi, XIONG Xin
Sulfonated modified ramie biochar (SBC) was prepared by a high temperature calcination-sulfonation method and used as a persulfate activator to effectively remove tetracycline hydrochloride (TCH) from aqueous solutions. The morphology and structure of SBC were characterized by scanning electron microscopy (SEM), specific surface area analyzer (BET) and Fourier transform infrared spectroscopy (FT-IR). Effects of initial pH value and the dosages of SBC and PS on TCH degradation in the SBC/PS system were investigated. Also, reuse properties of synthetic materials were examined. The results showed that SBC were lamellar mesoporous materials with abundant oxygen-containing and xanthate functional groups on their surface. Under the optimal conditions of initial pH value of 3, PS dosage of 10mmol/L and SBC dosage of 0.5g/L, the TCH removal of SBC/PS system reached 89.0% after 180min, which was significantly better than that of SBC, ramie straw original biochar (BC), PS and BC/PS systems. Within the experiment scope of this investigation, the degradation performance of TCH by SBC/PS system exhibited a falling-rising-falling pattern with the increase of pH (pH=3~11). With increasing dosage of PS and SBC, the removal of TCH tended to increase, then drop. Free radical quenching experiments and electron paramagnetic resonance (EPR) experiments showed that the sulfate radical (SO4-·), hydroxyl radical (·OH), superoxide radical (O2-·) and single oxygen (1O2) were produced and 1O2 played a dominating role in the SBC/PS system during the degradation of TCH. The recycling experiments revealed that SBC had an improved reusability. This study suggested that the SBC was an environmentally friendly and efficient non-metallic carbon-based persulfate activator with a promising prospect of applications.
2022 Vol. 42 (8): 3650-3657 [Abstract] ( 133 ) [HTML 1KB] [ PDF 1041KB] ( 289 )
3658 Performance of pollutant removal and responses of microbial community to Nano-ZnO stress in SBBR
GAO Jing-tian, HU Peng, CAI Yi-ting, LI Wei-ping, LIU Chao
In order to explore the tolerance of biofilm treatment system to Nano-ZnO, a sequencing batch biofilm reactor (SBBR) was constructed to carry out the Nano-ZnO stress test in SBBR system for determining the accumulation characteristics of Nano-ZnO on biofilm, investigating the removal performance of organic matter, nitrogen and phosphorus, and evaluating the Nano-ZnO tolerance threshold of SBBR. The responses of microbial community to Nano-ZnO were also analyzed by observing the changes of biomass, microbial activity and community structure. The results showed that low concentration (1~10mg/L) Nano-ZnO had no significant effect on the removal of COD, NH4+-N and SOP in SBBR except that 5mg/L Nano-ZnO promoted the microbial metabolic rate and biological activity. While the concentration of Nano-ZnO increased to 50mg/L, the inhibition on biomass and microbial activity increased, and the removal of COD, NH4+-N and SOP decreased by 26.45%, 57.83% and 43.50%, respectively. Nano-ZnO stress had the least effect on COD removal performance, but a great effect on NH4+-N. The Nano-ZnO tolerance threshold of SBBR indicated by COD was 911.49mg, while that of NH4+-N and SOP was 579.83mg. The diversity of microbial community in SBBR was reduced and the composition of community structure were changed under the stress of Nano-ZnO. The relative abundance of Proteobacteria and Chlorofiexi decreased from 21.09% and 7.03% to 8.00% and 2.60%, respectively, resulting in significant inhibition of NH4+-N removal. The abundance of Paesciabacteria suddenly increased from 9.33% to 56.64%, which played an important role in the efficient removal of organic matter. The pollutant removal performance and microbial activity showed that the tolerance of SBBR biofilm system to Nano-ZnO was stronger than that of activated sludge process.
2022 Vol. 42 (8): 3658-3665 [Abstract] ( 95 ) [HTML 1KB] [ PDF 845KB] ( 208 )
3666 Microscopic characteristics of sludge flocs as related to the movement velocity of microfauna: A case study of free-moving microfauna
HU Xiao-Bing, WANG Kun, LI Jing-Jing, CHEN Hong-Wei, SONG Wei-Wei, JIANG Yong-Bin, CHANG Jing, ZHONG Mei-Ying
This study was designed to figure out the problems such as misjudgment of micro-animals, heavy workload of classification and statistical analysis, etc., which exist in using changes in micro-animal community species to indicate the operating status of activated sludge. The possibility of reducing the dimensions of floc micromorphological parameters into a comprehensive index was judged with the principal component analysis (PCA). Meanwhile, the "micro-animal movement video acquisition + quantitative image analysis" method was used to characterize the movement speed of micro-animals(average linear velocity V and average angular velocity W) and identify the correlations between the movement speeds of seven freely moving micro-animals such as A. lynceus and the microscopic characteristics of sludge flocs in the SBR system. The results show a good correlation between the microscopic morphological parameters of the sludge flocs, which can be reduced to two comprehensive indicators (floc size and compactness (SC) and floc shape regularity (SR)). Both the floc SC and SR indicators were observed to have a significant correlation to the movement speed of Euchlanis sp., F. depressa and A. lynceus (|r|>0.50, P<0.05), so the change in the movement speed of typical free-moving micro-animals can quickly indicate the micro-morphological changes in sludge flocs.
2022 Vol. 42 (8): 3666-3673 [Abstract] ( 154 ) [HTML 1KB] [ PDF 1411KB] ( 182 )
3674 Anaerobic/microaerobic combined with A/(O/A)n to enhance nitrogen and phosphorus removal of aerobic granular sludge
LI Dong, WANG Xin-xin, ZHANG Yu-jun, ZHANG Jie
Three SBR reactors R1, R2 and R3 with the same specifications were set up, which were operated in A/O/A-A/O/A, A/O/A-A/O, and A/(O/A)n-A/O modes respectively. Using synthetic wastewater as the influent substrate, the inoculated sludge, consisting of 70% aerobic granular sludge and 30% flocculent sludge, were obtained from the laboratory for long-term starvation at 4℃. Under the same initial conditions, the activity recovery and short-cut nitrification and denitrification phosphorus removal performance of granular sludge under different operation modes were discussed. The results showed that the combined anaerobic/micro-aerobic A/(O/A)n alternating operation mode had great advantages in realizing the activity recovery of granular sludge and the performance of pollutant removal. The dense granules were formed with an average particle size of 802.98μm in R3, and the EPS content reached 94.52mg/gVSS, indicating that the alternating operation mode of combined anaerobic/microaerobic stimulated microorganisms to secrete more EPS, and the granule structure was more stable. During the stable operation period, the removal efficiency of COD, TP and TN of R3 reached 92.45%, 93.72% and 97.24% respectively. Meanwhile, the proportion of denitrifying phosphorus accumulating organisms with nitrite as electron acceptor in the system reached 51.46%, which could realize the simultaneous enrichment of AOB and DPAOs, thereby exhibiting good pollutant removal effect.
2022 Vol. 42 (8): 3674-3682 [Abstract] ( 96 ) [HTML 1KB] [ PDF 716KB] ( 290 )
3683 Catalytic degradation of coking tail wastewater by particle electrodes loaded with transition metals
YOU Xin-yu, LIU Yu, QIN Lin-lin, YANG Shuai, ZHANG Wen-wen, LIANG Wen-yan
Large quantities of refractory organic matters still leave in the coking wastewater after biological treatment, making wastewater not meet the requirements of discharge or recycling. In the present study, activated carbon was applied as carrier. Five kinds of particle electrodes that were loaded with single elements of Ni, Fe and Co and binary elements of Ni-Fe and Co-Fe, were prepared and used to degrade the simulated coking tail-wastewater. The results showed that the particle electrodes loaded with binary elements achieved better treatment effects than those loaded with single elements. Ni-Fe/PAC possessed the best degradation performance among the electrodes, with COD and TOC removal efficiency of 70.1% and 40.1%, respectively. Ni-Fe/PAC also possessed the highest oxygen evolution potential and the lowest Tafel slope, namely 2.25V and 86mV/dec, respectively. The crystal structure was consisted by metallic Ni and Fe and small amount of iron oxide. The addition of particle electrodes resulted in the effluent to be alkaline. The loading Co increased the alkalinity, while the Fe was beneficial to reduce the pH value of effluent. The degradation effects of the three category organics in simulated wastewater were in the order of polycyclic aromatic hydrocarbon < heterocyclic compound < benzene series during Ni-Fe/PAC processes. Ni-Fe/PAC can catalyze the generation of ·OH and new atomic hydrogen. The degradation of organic matters was mainly fulfilled through indirect oxidation.
2022 Vol. 42 (8): 3683-3689 [Abstract] ( 154 ) [HTML 1KB] [ PDF 997KB] ( 225 )
3690 Characteristics of the combination between colloids and dissolved organic matter in urban surface runoff
LIU Dian-wei, DU Xiao-li, FU Xiao-yu, CUI Shen-shen, DAI Xin-yi
To characterize the combination between colloids and dissolved organic matter (DOM) in urban runoff, the adsorption behaviors of both colloids and DOM under different pH conditions were examined to reveal its mechanisms. The results showed that the Langmuir model described the isothermal sorption of DOM by runoff colloids at different pH values better, and the maximum sorption capacity decreased gradually with an increase in pH. The maximum equilibrium adsorption capacity at pH 3 was 4.0 times more than that at pH 6. The absolute value of zeta potential of runoff colloids increased after adsorption with DOM and then the runoff colloids became more stable and easier to migrate. HoA and HoN are two main fractions in the runoff DOM and account for 35.0% and 24.3% of the total DOC concentration, respectively, and can be combined with runoff colloids most easily, implying that the DOM fractions with high molecular weight are more likely combined with runoff colloids. The combination between runoff colloids and DOM can be achieved through hydroxyl substitution, surface complexation and electrostatic attraction.
2022 Vol. 42 (8): 3690-3695 [Abstract] ( 134 ) [HTML 1KB] [ PDF 353KB] ( 275 )
3696 Oxidation and degradation mechanisms of ofloxacin by potassium ferrate
LI Ya-nan, FENG Zhuo, WANG Jia-qi, GUO Kai, ZHANG Guo-kai
The oxidation and degradation mechanisms of quinolone antibiotic ofloxacin (OFL) by potassium ferrate (Fe (VI)) were studied. High performance liquid chromatography(HPLC), liquid chromatograph mass spectrometer(UPLC-QTOF-MS) and other methods were used to investigate the effects of Fe (VI) dosage, pH, temperature and coexisting substances on OFL removal, analyze the reaction kinetics, calculate the contribution rate of Fe(VI) in the process of OFL oxidation, identify the products of Fe(VI) and predict the main reaction pathways.The results show that the degradation efficiency of OFL reached 92.38% after 30 minutes of oxidation, with the molar ratio of Fe (VI) to OFL of 40:1, pH of 8 and temperature of 25 ℃. In the first 5 minutes' rapid reaction stage, OFL degradation conformed to pseudo second-order reaction kinetics, and the activation energy was 28.17kJ/mol. The contribution of Fe (VI) and the high-valent intermediate iron species to OFL removal was 70.34%, and humic acid significantly inhibited the reaction. Three main oxidation pathways for OFL degradation by Fe (VI) were proposed based on the analysis of reaction products, and the ring cleavages of quinolone, piperazine and oxazine rings were mainly achieved through decarboxylation, demethylation, decarbonylation and hydroxylation.
2022 Vol. 42 (8): 3696-3703 [Abstract] ( 99 ) [HTML 1KB] [ PDF 471KB] ( 246 )
3704 Preparation optimization of amphiphilic chitosan and removal of algae by air flotation
WANG Yong-lei, WANG Xing-lin, LI Ya-nan, JIN Li, SHAO Ming-rui, LYU Bing-qi, QI Hao-ran, XUE Jie
Three amphiphilic CTS were used for PosiDAF algal removal experiment, and the algal removal effects under different conditions were compared to explore the algal removal mechanisms. The results showed that the amphiphilic modification can enhance the water solubility of CTS while reduce the thermal stability of CTS. The significant degree of influence on the responding value (substitution degree) was as follows:carbon chain length>reaction time>reaction temperature>raw material feeding ratio. When the 1.0mg/L N-2hydroxypropyl trimethyl chitosan ammonium chloride (C4-HTCC) was used as modifier, the effectiveness of algae removal was the best, reaching 93.47%; because the modified microbubbles have strong electrostatic attraction.
2022 Vol. 42 (8): 3704-3712 [Abstract] ( 112 ) [HTML 1KB] [ PDF 1689KB] ( 269 )
3713 Pickering emulsion for enhancing oxidative degradation of trichloroethylene nonaqueous-phase liquid in groundwater
YANG Shuo, ZHAO Wen-chu, YAN Xiu-lan, ZHANG Dan
Four kinds of SiO2 particles were synthesized with different length to diameter (L/D) ratios to form oil -in-water Pickering emulsions so as to control the water/trichloroethylene (TCE) NAPL interface and improve TCE dissolution. The characteristics and stability of the formed Pickering emulsion and effects of colloidal particle concentration, ionic strength in water and water/NAPL ratio were investigated. Results showed that the droplets in the Pickering emulsion formed from SiO2 particles with L/D ratio of 2.3 had uniform size of 10µm and remained stable within 10 days. The emulsion index was up to 63% in this system. Moreover, the formed Pickering emulsion exhibited stability under low shear strain, facilitating groundwater in situ remediation. The results from comparing the kinetics of NAPL dissolution and oxidative degradation under Pickering emulsified and non-emulsified conditions indicate that Pickering emulsification could significantly elevate the dissolution rate of NAPL by increasing the interface area between the two phases, thereby achieve an increase in the degradation rate of NAPL phase pollutants.
2022 Vol. 42 (8): 3713-3719 [Abstract] ( 117 ) [HTML 1KB] [ PDF 3087KB] ( 284 )
3720 Molecular simulation of NH4+ adsorption by kaolinite with different water content under temperature and pressure
YANG You-wei, WANG You-lin, LUO Yu-xia, LIU Xin-qi, GUO Chang-sheng, CHEN Ming, WANG Chun-ying
In order to study the microscopic situation of NH4+ adsorption by kaolinite, kaolinite models with different hydration degrees of 4×2×1 were constructed after the convergence test of kaolinite monocytes by Material Studio software. The theoretical calculation and adsorption experiment of the model cell were carried out by using the methods of quantum mechanics and classical mechanics. The results showed that the stable structure model of kaolinite is obtained (error < 2%) under the conditions of exchange correlation functional GGA-PW91, K point 4×3×2 and truncation energy 600eV. The adsorption of NH4+ by kaolinite was obviously affected by temperature. With the increase of temperature, the adsorption capacity decreases gradually, which was consistent with the experimental results. The kinetic results showed that the adsorption type was mainly physical adsorption, and the adsorption forces were Van der Waals force and Coulomb force. The research results were helpful to supplement the research on the kaolinite properties and have a guiding role in the control of ammonia nitrogen pollution in soil of rare earth mines.
2022 Vol. 42 (8): 3720-3727 [Abstract] ( 98 ) [HTML 1KB] [ PDF 2695KB] ( 387 )
3728 Combined control of phosphorus release from sediment by red soil and Vallisneria spiralis
ZHANG Yu, YIN Yue-peng, TANG Jin-yong, CAO Xi, LIU Jing-jing, ZHANG Wen
The effect of single and combined remediation on phosphorus removal from polluted sediment was studied by using the in situ combined remediation technology of red soil and Vallisneria spiralis(RS +VS). The results showed that the removal capacity of sediment P by RS and VS combined remediation was higher than that by single remediation. In the 37d batch experiment, the phosphorus released from sediment in the RS+VS group was inhibited by 91%. Compared with the phosphorus released from sediment in the RS+VS group without coverage, the dissolved active phosphorus (SRP) in the overlying water decreased from 1.41mg/L to 0.12mg/L. RS+VS combined remediation had a significant effect on the fixation of sediment phosphorus, The unstable ferrous phosphorus (Fe(II)-P) and iron aluminum bound phosphorus (CDB-P) were transformed into inert calcium phosphorus (Ca-P). The content of Ca-P in sediment increased by 51%, while Fe(II)-P and CDB-P decreased by 1% and 24% respectively, effectively reducing the risk of phosphorus release from sediment to overlying water. In conclusion, RS+VS combination can be applied to treat the internal phosphorus load in eutrophic waters to realize the coordinated removal of sediment phosphorus. At the same time, RS and VS are cheap and widely distributed, and can be used as a potential high-benefit phosphate adsorbent in practical projects.
2022 Vol. 42 (8): 3728-3735 [Abstract] ( 112 ) [HTML 1KB] [ PDF 1285KB] ( 332 )
3736 Adsorption performance of tetracycline in water by alkali-modified wheat straw biochars
LIU Zong-tang, SHAO Jiang, LI Yan, WU Yan-ru, AN Yan, SUN Yu-feng, FEI Zheng-hao
The wheat straw biochar (WBC) was prepared through carbonization for 6 hours at pyrolyzing temperatures of 873K; and three alkali-modified WBCK (WBCK1, WBCK2, and WBCK3) with different KOH-char mass ratios (1:1, 2:1, and 3:1) were subsequently prepared with KOH impregnation modification. The structure characteristics and surface properties of WBCK were characterized with scanning electron microscopy (SEM), specific surface area and porosity analyzer (SSAP), and Fourier transform infrared spectrometer (FT-IR). Batch adsorption experiments were carried out to evaluate the adsorption performance of tetracycline (TC) onto WBCK. Compared to WBC, WBCK possessed a richer pore structure and a higher specific surface area. The adsorption capacities of TC by WBCK were significantly enhanced. The adsorption of TC by WBCK followed the pseudo-second-order kinetics model, and the adsorption rate constants were in the order of k2(WBCK2) > k2(WBCK3) > k2(WBCK1). The adsorption capacities of TC by WBCK increased with an increase in temperature, and the physical adsorption and chemical adsorption coexisted in the adsorption process. Langmuir, Freundlich, and Temkin model could describe the adsorption isotherm perfectly, implying that the adsorption mechanism is complicated. The adsorption of TC by WBCK was a spontaneous endothermic process with entropy increment. WBCK had good adsorption performance for TC in the solution pH range of 4.0 to 8.0. WBCK1, WBCK2, and WBCK3 had good reusability, especially, the adsorption removal efficiency of WBCK2 decreased by only 13.9% after five cycles.
2022 Vol. 42 (8): 3736-3743 [Abstract] ( 144 ) [HTML 1KB] [ PDF 945KB] ( 469 )
3744 Dielectric barrier discharge plasma aging of microplastics and its effect on Zn(II) adsorption
LU Wei, SANG Wen-jiao, LI Min, ZHANG Wen-bin, JIA Dan-ni, ZHAN Cheng, HE Yong-jian, CHEN Cui-zhen, XIANG Xue-lian
In order to shorten the aging time of microplastics and mimic the natural aging conditions in the experiment, dielectric barrier discharge (DBD) plasma was used in the aging experiments of polyethylene microplastics (PE-MP) and polypropylene microplastics (PP-MP). And the adsorption process and mechanism of Zn(II) on PE-MP and PP-MP before and after aging was investigated. With the extension of discharge time and the elevation of input voltage, tiny cracks or holes appeared on the surface of microplastics and oxygen-containing functional groups were formed. The Zn(II) adsorption capacity of aged PE-MP and PP-MP was increased by 22.7% and 14.8%, respectively. The adsorption of Zn(II) on microplastics before and after aging conformed to the pseudo-second-order kinetic model. The intra-particle diffusion model showed that the adsorption process of Zn(II) on microplastics could be involved three processes:rapid adsorption, slow adsorption and adsorption equilibrium. In addition, the adsorption of Zn(II) on microplastics before and after aging conformed by Langmuir model. The thermodynamic results indicated that the adsorption of Zn(II) on microplastics was a spontaneous endothermic process. Ca2+, humic acid and low pH were not conducive to the adsorption of Zn(II) by microplastics.
2022 Vol. 42 (8): 3744-3754 [Abstract] ( 166 ) [HTML 1KB] [ PDF 1375KB] ( 554 )
Solid Waste
3755 A review on pyrolysis of rural household garbage
YAN Bei-bei, YANG Xue-zhong, HOU Lin-tong, MA De-gang, LI Jian, SUN Yu-nan, CHENG Zhan-jun, CHEN Guan-yi
The clean disposal of rural household garbage is crucial to the environmental protection. It contributes a lot to the development of economic and the improvement of people's livelihood. Meanwhile, clean disposal of rural garbage is also one of the most important tasks for building the ecological civilization and beautiful country. Under this background, the rural household garbage should not only be reduced, but also achieve the resource utilization and energy recovery. In this paper, the production and distribution of Chinese rural household garbage are introduced, and the conventional treating models and technologies are discussed. Pyrolysis is an emerging technology for treating rural household garbage. A comprehensive evaluation on the pyrolysis of rural household technology is conducted with focusing on the process control, production utilization, design of reactor, and research frontier. Some related laws or regulations are introduced, and some demonstration plants are elaborated. Hopefully this paper can provide some insights to the pyrolysis of rural household garbage.
2022 Vol. 42 (8): 3755-3769 [Abstract] ( 188 ) [HTML 1KB] [ PDF 549KB] ( 560 )
3770 Enhancement of acidification from waste activated sludge via anaerobic fermentation by free nitrous acid (FNA) pretreatment assisted by ultraviolet
YIN Xiao-yun, LIU Zhi-hong, ZHOU Ai-juan, LI Ya-nan, YUE Xiu-ping, CUI Zhi-xuan
In order to break the bottleneck of the limited hydrolysis performance and low short chain fatty acids (SCFAs) production efficiency from waste activated sludge (WAS) during the traditional anaerobic fermentation, this work investigated the effect of the ultraviolet (UV) assisted free nitrous acid (FNA) pretreatment on WAS disintegration and acidification, and compared with thermal (H) and ultrasonic (US) coupled with FNA pretreatment. Results revealed that UV assisted FNA co-pretreatment (FNA-UV) had a synergistic effect on disruption of both extracellular polymeric substances and cell envelope.･OH and･O2-, as the main reaction intermediates, their intensities in FNA-UV group were much stronger than that obtained in other pretreatment groups (FNA-US and FNA-H). Moreover, these two free radicals, with the intermediates such as ･NO,･NO2 and ONOO-, further promoting the release of soluble organics. The contents of soluble carbohydrates and protein were 60% and 90% higher than that obtained in FNA group respectively, which served more soluble substrates for SCFAs generation. Accordingly, SCFAs concentration peaked at 4d in FNA-UV group (201.8±4.8)mg COD/g VSS with 56.8% acetic acid (HAc)), which was 67% higher than that of FNA group. Carbon balance analysis at the final stage of the fermentation showed that UV assisted FNA pretreatment played an important role in sludge reduction, release and transformation of soluble substrates, and finally SCFAs production. The functional microbial consortia analysis indicated the anaerobic fermentation bacteria and nitrate-reducing bacteria were obviously enriched in FNA-UV group, which were 23.7%~270.6% higher than that obtained in other groups.
2022 Vol. 42 (8): 3770-3779 [Abstract] ( 133 ) [HTML 1KB] [ PDF 1036KB] ( 242 )
3780 The extraction of protein from surplus sludge catalyzed by thermophilic Bacillus terrestris hydrolysis
DING Ya-ting, ZHONG Wei-zhang, QIN Xue, NING Zhi-fang, LI Yue, CHEN Sai-nan
For optimizing the processing conditions to realizing the harmless treatment and resource utilization of excess sludge, the thermophilic bacteria (Bacillus terrestris), which can produce extracellular enzymes such as protease and amylase, were selected from the high-temperature compost substrate and used to extract sludge nitrogen source in this study. Then effects of reaction time, sludge solid content and inoculum amount of crude enzyme solution of thermophilic bacteria on protein extraction were evaluated to determine the optimum reaction conditions. The results show that effects of various factors on protein recovery during hydrolysis were in the order of inoculation amount > time> solid content; and the optimal processing conditions included pH=7, T=60℃, t=8h, and solid content of 4% under which we observed thermophilic bacteria inoculation rate of 20%, protein extraction rate of 32.05%, amino acid content of 359.6mg/L, and polypeptide content of 1060.1mg/L, and that the sludge supernatant particle size decreased gradually with the reaction.
2022 Vol. 42 (8): 3780-3787 [Abstract] ( 103 ) [HTML 1KB] [ PDF 1515KB] ( 326 )
3788 Characteristics of silver nanoparticles and microplastics co-migration in simulated landfill columns
HE Chang, ZENG Xiao-lan, ZHANG Cun-kuan, XU Xiao-tang, DING Wen-chuan
Lab-scaled simulated landfill columns and synthetic leachate were prepared to investigate the transport of silver nanoparticles (AgNPs) and microplastics (MPs) in municipal solid waste landfill. The results showed that stability of AgNPs and MPs in leachate increased with the landfill time extending while they existed in a single system as well as in a binary system. Thus the migration ability of these pollutants in the landfill was promoted so that more pollutant particles could be discharged from the middle and aged landfill along with leachate. In comparison with single system, AgNPs and MPs coexisting system facilitated the transport of AgNPs but slightly inhibited the transport of MPs. In term of DLVO theory and colloidal filtration theory, it suggests that MPs of higher mobility could serve as carriers of AgNPs and compete with AgNPs for adsorption sites on the solid media, thereby promoting the transport of AgNPs. Inversely, the coexisting AgNPs could reduce the negative surface charge on the MPs to weaken the stability of pollutants particle, and could provide additional deposit sites for MPs through AgNPs pre-deposition on the solid media, thereby inhibiting the transport of MPs.
2022 Vol. 42 (8): 3788-3795 [Abstract] ( 120 ) [HTML 1KB] [ PDF 1381KB] ( 315 )
3796 Effects of biomass blending on combustion performance of sewage sludge
SHI Yuan-yuan, YAN Feng, CHEN Jing-jing, DONG Chun-ling, GUO Rui-cheng, ZHANG Zuo-tai
In term of the effects of peanut shell blending on the combustion performance pollution emission of sewage sludge, the effects of heating rate and peanut shell blending ratio on the combustion process were analyzed. The results showed that when the peanut shell blending ratio was 40% and the heating rate increased from 5℃/min to 30℃/min, the composite combustion performance index and volatile matter release characteristic index increased 6.9 times and 4.5 times respectively. When the heating rate was 30℃/min, and the blending ratio of peanut shell increased from 0% to 40%, the comprehensive combustion performance index and volatile matter release characteristic index of samples increase by 1.7 times and 5.6 times, respectively, indicating that peanut shell blending can effectively improve the combustion performance of sewage sludge. The results of non-isothermal kinetic fitting showed that the activation energy decreased from 89.16 kJ/mol to 69.73 kJ/mol with the increase of peanut shell blending ratio, which was beneficial for the combustion reaction. The real-time monitoring of pollution gas showed that the peak of NO emission decreased 60% when the peanut shell blending ratio increased from 10% to 40%, indicating that the peanut shell could significantly reduce the emission of pollution gas during combustion process.
2022 Vol. 42 (8): 3796-3803 [Abstract] ( 106 ) [HTML 1KB] [ PDF 1427KB] ( 317 )
3804 Evaluating the operation efficiency of kitchen waste anaerobic digestion with carbon and nitrogen balance model
SHI Zhen-chao, GE En-yan, HE Pin-jing, PENG Wei, ZHANG Hua, Lü Fan
A typical AD plant for kitchen waste was taken as a case to evaluate carbon and nitrogen flow using the carbon and nitrogen balance model, and the operation performance was evaluated through the distribution of carbon and nitrogen in solid, liquid and gas phases. The results showed that the carbon and nitrogen material flow can fit well with the results of biogas production (goodness of fit was 0.88). The modified solid-liquid separation unit in the model significantly improves the simulation results of solid content (TS) of solid digestate and liquid digestate (goodness of fit increased to 0.97 and 0.82, respectively). Clearly, the carbon and nitrogen balance model-assisted approach, integrated with the actual gas production index (RBMP), is suitable for evaluating the operating efficiency.
2022 Vol. 42 (8): 3804-3811 [Abstract] ( 135 ) [HTML 1KB] [ PDF 616KB] ( 323 )
3812 Effects of red mud on compost maturity and Cd resistance control of rice
ZHOU Hong-yan, CHEN Zhe, LI Kan-qi, LENG Wei-gui, WANG Zong-kang
Red mud was used as an additive to conduct aerobic composting experiments of chicken manure for evaluating effects of red mud on temperature, pH, electrical conductivity (EC), and seed germination index (GI) during composting. The evolution characteristics of humic acid (HA) components during composting were analyzed by combining three-dimensional fluorescence with ultraviolet-visible light spectrum; and the pot experiments were also conducted to explore the barrier effect of compost products on rice cadmium in the mining soil. The results showed that red mud increased the temperature of the compost during the high temperature period. The EC of both groups decreased significantly after composting, however, the EC of red mud compost (4.29mS/cm) was much higher than that of chicken manure compost (3.59mS/cm).The GI of chicken manure compost and red mud compost increased with composting time by; 100.2% and 96.44%, respectively, at the end of composting, indicating that the products of neither red mud compost nor chicken manure compost exhibited phytotoxicity. The protein-like substances in the HA of the two kinds of composts were converted into relatively stable humus-like substances throughout the composting process. A significant increase in SUVA254, SUVA280, and A226-400 of HA indicates the elevated humification degree of compost. In addition, red mud could optimize the humification parameters, implying that the addition of red mud can accelerate the humification process of the heap. In pot experiments, both chicken manure compost and red mud compost increased soil pH and reduced the concentration of DTPA-Cd in soil and total Cd in brown rice. After applying 2g/kg red mud compost, the Cd content in brown rice decreased significantly (by 58.68%) from 0.42mg/kg to 0.17mg/kg after composting. Therefore, red mud can accelerate the composting efficiency to a certain extent. The application of compost products can inhibit the bioavailability of Cd in both soil and rice plants, and an addition of red mud can lead to a higher composting efficiency.
2022 Vol. 42 (8): 3812-3821 [Abstract] ( 138 ) [HTML 1KB] [ PDF 1308KB] ( 277 )
3822 Reward and punishment incentive mechanism of domestic waste classification in rural China: Based on complex network evolutionary game model
WEI Xi-kai, MA Ben
Based on the characteristics of rural "acquaintance society", this paper adopts the complex network evolutionary game model for the first time to analyze the dynamic impacts of reputation loss and reward policy on the diffusion depth of farmers' waste classification behavior through numerical simulation. The results show that, if the government does not intervene, garbage classification will not be spontaneously, continuously and widely popularized in rural areas. Within a certain range, improving reputation or reward can significantly promote the classification of farmers. Only relying on a single policy cannot achieve deep diffusion for classification. If both reputation loss and reward incentives are used, desirable effect of high diffusion depth can be achieved based on low policy intensity. An increase in free-ride earnings will inhibit the diffusion depth of waste classification. EWA learning strategy focusing on experience learning and adaptability is more helpful to promote the diffusion of waste classification. The above conclusions are not only comprehensively applicable to rural areas with different initial classification state, learning abilities and population sizes, but have universal implication significance for rural waste classification in China. Finally, this paper puts forward the choice of waste classification incentive policy by fully taking the advantages of "acquaintance society" and building a waste classification incentive policy consistent with the socio-economic characteristics of rural areas.
2022 Vol. 42 (8): 3822-3831 [Abstract] ( 192 ) [HTML 1KB] [ PDF 1471KB] ( 244 )
3832 Long-term effect of carbonation on heavy metals in fly ash of different alkalinity
SHE Kai-lang, LI Ping, LIU Jing-cai, YAO Guang-yuan, XU Ya, XU Rong-bin, ZHAO Yu-xin, LIU Yu-qiang
Through carbonation treatment of domestic waste incineration fly ash in different areas, and the physical and chemical characteristics of fly ash are analyzed by XRF, SEM, and XRD, then the long-term impact of CO2 on the excessive heavy metals of Zn, Pb and Cd in different incineration fly ash is studied by pH measurement, heavy metal leaching experiment and heavy metal speciation analysis. The research shows that the incineration fly ash displayed different alkalinity characteristics due to the reduction of flue gas emission limits in the incineration process, which required a large amount of deacidification agent such as calcium hydroxide. According to the pH value of the leaching solution after the acetic acid buffer solution leaching experiment, the fly ash is divided into "acid ash" and "alkali ash", and the long-term carbonation experiments are carried out. The results showed that the leaching toxicity of heavy metals in "acid ash" was much higher than that of "alkali ash", but the leaching concentration of heavy metals Zn and Cd in "acid ash" after carbonation are reduced by 10%~18% and 9%~30% respectively. The leaching concentration of heavy metals Zn and Cd in "alkali ash" increased significantly, and the maximum leaching concentration exceeded 1.46 and 63.2 times of the standard for pollution control on the municipal solid waste incineration. The leaching of amphoteric heavy metal Pb in "acid ash" and "alkali ash" is not regular after carbonation, but in general, carbonation has a greater effect on heavy metal Pb in "alkali ash". Finally, the change law of heavy metals in fly ash before and after carbonation is analyzed by BCR sequntial extraction procedure. The BCR results show that the leaching concentration of heavy metals Zn and Cd in "acid ash" shows a downward trend affected by the increase of the proportion of T4after carbonation, but the proportion of T1in some samples increases, which indicated that such heavy metals still have leaching risk. However, the leaching concentration of heavy metals Zn and Cd in "alkali ash" shows an increasing trend affected by the increase of the proportion of T1after carbonation. Therefore, we should focus on the leaching characteristics of heavy metals in fly ash with different alkalinity before landfill disposal, and provide guarantee for long-term stable landfill of fly ash.
2022 Vol. 42 (8): 3832-3840 [Abstract] ( 151 ) [HTML 1KB] [ PDF 1591KB] ( 235 )
Soil Pollution Control
3841 Characteristics and numerical simulation of the co-transport of Cd/Zn/Cu in soils under different redox potentials
LI Bo-liang, JI Shu-hua, YU Tong, XU Shao-hui, LIN Qing
The column experiments and numerical simulations were conducted to evaluate effects of redox potentials (Eh) on the transport of cadmium (Cd), zinc (Zn), and copper (Cu) in soils. The results showed that the competitive adsorption capacity of Cu was greater than that of Cd and Zn, resulting in a lower mobility in the soil under different redox potentials. Due to the competitive adsorption of Cd, Zn, and Cu, the "snow plow effect" takes place, resulting in the higher concentrations of Cd and Zn in the effluents than in the input. Compared to the control, both the increase and decrease in Eh promote the transport rate of Zn and Cd, but have different impacts on recovery rate. With an increase in Eh, the transport of Cu can be promoted in the soil. The good performance of TSM and OSM models for simulating the transport behavior of heavy metals further confirms that the adsorption of heavy metals in soils is time-limited (f < 0.7). In general, both the influence of redox potential and the concentration superimposition caused by heavy metal competitive adsorption should be considered in the evaluation and prevention of heavy metal compound contaminated soils.
2022 Vol. 42 (8): 3841-3848 [Abstract] ( 133 ) [HTML 1KB] [ PDF 530KB] ( 229 )
3849 Effect of phosphate on monothiosarsenate adsorption to soil
ZHANG Jin-xian, SHAN Hui-mei, LIAO Dan-xue, PENG San-xi, DU Hai-ling, LIU Yun-quan, SHI Qian
In this study, batch experiments and characterization analysis were conducted to explore the characteristics and mechanism of MTA adsorption on soil by adding different concentrations of phosphate. Results showed that:the Elovich kinetic model and Langmuir isothermal adsorption model can better fit the adsorption process of MTA on soil, indicating that the adsorption process of MTA was mainly affected by the diffusion of pore size. The maximum adsorption capacity of MTA on soil was 254.214mg/kg. With the increase of the initial concentrations of adding phosphate in the solution, the equilibrium adsorption capacity of MTA on soil gradually decreases, and that of phosphate gradually increases. SEM-EDS results showed that a small amount of As was detected on the surface of soil whether adding phosphate or not. In the system with phosphate addition, the soil showed a relatively low content of As, confirming that the presence of phosphate can reduce the adsorption of MTA on soil. In addition, XRD results showed that MTA can form endosphere complexes of -[2Al(H2AsO4)3],≡Al2O2AsO(SH) and -[2Fe(H2AsO4)3] with Fe-Al minerals in soil samples, and phosphate can form endosphere complexes with hydroxyl groups on the surface of soil, weakening the adsorption of MTA.
2022 Vol. 42 (8): 3849-3857 [Abstract] ( 111 ) [HTML 1KB] [ PDF 838KB] ( 220 )
3858 Bacterial community composition and co-occurrence network before and after enrichment of oil-contaminated soil
YU Tian-fei, LIU Xiao-dong, AI Jia-min, WANG Jia-min, GUO Yi-dan, LIU Xin-hui, JIANG Ying-ying, DENG Zhen-shan
Enrichment culture is one of the most important aspects of isolating petroleum degrading microorganisms, in which the microbial community undergoes corresponding succession. The bacterial community structure, co-occurrence network and core genus composition before and after the enrichment were conducted with the streak plate method, colony PCR and Illumina-MiSeq high-throughput sequencing technology to investigate the succession pattern of bacterial communities in oil-contaminated soil during the enrichment process. The microorganisms in the enriched system were isolated and identified. We observed that the culturable microorganisms in the enriched system belong to 34 genera and 53 species, among which 3 are of potential new species, and Dietzia maris OS33 and Rhodococcus qingshengii OS62-1are able to degrade oil. High-throughput sequencing results show that Proteobacteria and Actinobacteria are the main phylum, whenever it is before or after enrichment. But after enrichment, these two phylums are of absolutely dominant groups and the abundance is up to 97.98%. At the genus level, the dominant genuses are transformed from Psuedomonas, Rhodococcus,Bacillus and Xanthomonas to Dietzia, Unspecified_Idiomarianceae and Halomonas, the core genera are altered to Dietzia for degrating petroleum. The co-occurrence networks of bacterial communities are more simplified and stable after enrichment. The core microorganisms are altered to Pseudomonas, Lysinibacillus, Pseudochrobactrum, Agrobacterium and Lactobacillus which are related to petroleum degradation. The non-petroleum degrading bacteria P. songnenensis P35can cooperate with the oil degrading bacteria D. maris OS33to degrade petroleum.
2022 Vol. 42 (8): 3858-3866 [Abstract] ( 121 ) [HTML 1KB] [ PDF 2913KB] ( 255 )
Environmental Ecology
3867 Retrieval of suspended particulate matter concentration from Sentinel-3 OLCI image in the Coastal Waters of Qinhuangdao
WANG Lin, WANG Xiang, WANG Xin-xin, MENG Qing-hui, MA Yu-juan, CHEN Yan-long
Based on the in-situ observed remote sensing reflectance (Rrs), SPM and chlorophyll a concentration in this area from 2013 to 2021, here a regional SPM retrieval model was developed specifically for the Sentinel-3 OLCI image. The results showed that the typical empirical models commonly used in the previous literatures were not applicable to the Qinhuangdao coastal waters, here three wavebands of 490, 620 and 708.75nm are used as the sensitive ones for retrieval of SPM concentration, and the waveband of 560nm was used as the reference one, a four-band retrieval model of SPM concentration (R2=0.69, MAPE=24.79%, RMSE=2.82mg/L) was established. The accuracy of SPM concentration remote sensing product was tested from July 24, 2021, and the mean absolute percentage error (MAPE) between the observed and the retrieval values reached 13.24%. The four-band model was then applied to the Sentinel-3 OLCI images of Qinhuangdao coastal waters from January to December 2021, and the monthly average SPM concentration are obtained and analyzed. It was found that the SPM concentration in this area displays obvious temporal and spatial variation characteristics, generally high in coastal waters and low in offshore waters, high in autumn-winter and low in spring-summer. The annual averaged SPM concentration was decreasing year by year from 2018 to 2021, and the water was becoming clearer and clearer.
2022 Vol. 42 (8): 3867-3875 [Abstract] ( 132 ) [HTML 1KB] [ PDF 3605KB] ( 244 )
3876 Dissolved oxygen prediction model based on variable importance measures and random forest: A case study of Shenzhen Bay
YANG Ming-yue, MAO Xian-zhong
A real-time prediction model for dissolved oxygen was established by using Pearson correlation analysis, variable importance measures and random forest method. Taking Shenzhen Bay as an example, the model was used to predict the dissolved oxygen in 1h, 3h, 6h and 12h based on the buoy data. The results showed that the optimal input conditions of the model were pH, water temperature, chlorophyll A, redox potential and blue-green algae. The correlation coefficient of 1h prediction results was more than 0.9, and the 6h prediction results could meet the engineering requirements to a certain extent. However, the prediction of low dissolved oxygen events might be within 3h.
2022 Vol. 42 (8): 3876-3881 [Abstract] ( 167 ) [HTML 1KB] [ PDF 1001KB] ( 231 )
3882 Interpretation of sensory query distance during upstream migration of Schizothorax prenanti
DENG Yue-xi, TANG Xi-liang, YAN Zhong-luan, WANG Xiao-ming, LU Jing-ying, AN Rui-dong, LI Jia
In this paper, an endemic fish located in Southwest China, Schizothorax prenanti (32.32±2.73)cm, was selected as the research object to test the volitional swimming behavior during the upstream migration in an open-channel flume with alternative flow regimes, and to interpret the extent to which swimming speed, turning times, angle and angle difference under different mesh sizes can match with the real swimming trajectory. The results showed that when the mesh size was less than or equal to 0.30m, there was no significant difference between the average swimming speed, the number of turns, the angle and the difference of turns with real swimming data. In addition, fish are more inclined to swim in the velocity ranged from 0.20 to 0.40m/s with the search angle ranged from -49º to 49º in horizontal direction.
2022 Vol. 42 (8): 3882-3889 [Abstract] ( 121 ) [HTML 1KB] [ PDF 2061KB] ( 243 )
3890 Hopanoids biomarkers and their indications in the marine carbon and nitrogen cycles
YIN Mei-ling, DUAN Li-qin, SONG Jin-ming, YUAN Hua-mao, LI Xue-gang
The microbe-mediated marine biogeochemical cycles of carbon (C) and nitrogen (N) have an important impact on the global climate changes. The hopanoids of pentacyclic triterpenoids, including biological hopanoids (e.g., bacteriohopanepolyols (BHPs)) and geological hopanoids (e.g., hopanes), are important lipid biomarkers for indicating and reconstructing C and N cycles in modern and ancient environments. In this paper, we reviewed the biosynthetic pathways and physiological functions of hopanoids, and their roles as indicators in the key processes of the marine C and N cycles (i.e., nitrogen fixation, nitrification, anammox, methane oxidation and terrestrial organic matter input). The hopanoids in microbial membrane lipids are mainly regulated by enzymes of hopanoids synthesis and modification encoded with hpn gene, which are closely related to microbial physicochemical characteristics and environmental conditions. The oxygen permeability of cell membrane can be regulated by 2-methyl hopanoids, 2-methyl cyclitol ether and unsaturated cyclitol ether to protect nitrogenase, being able to indicate the diazotrophic cyanobacteria and N-fixation. Marine anammox bacteria Candidatus Scalindua is the only producer known as BHT-x (one of bacteriohopanetetrol isomers) so far, which can indicate marine anammox and hypoxic environment. Soil markers BHPs and terrestrial inputs indicator of Rsoil can track the input and migration of terrestrial organic matter to the ocean. Biomarkers 35-amino BHPs and 3-methyl (amino) BHPs can indicate aerobic methane oxidation. Bacteriohopanehexol and 3-methyl bacteriohopanehexol can indicate nitrite-reducing methanotrophy. With the development of molecular biology, genomics and instrumental analysis technology, hopanoids will play a more important role in indicating marine C and N cycles.
2022 Vol. 42 (8): 3890-3902 [Abstract] ( 137 ) [HTML 1KB] [ PDF 981KB] ( 455 )
3903 Identifying factors affecting regional fractional vegetation cover based on a combination of factor regression and interaction—A case study on the Three-River Headwaters Region
ZHAO Dan, WANG Zu-wei, ZHANG Guo-zhuang, XU Yong-min, SUN li-jian
The spatial heterogeneity of FVC in the Three-River Headwaters region was analyzed using the normalized vegetation index (NDVI) obtained from SPOT VEGETATION, and the impacts of natural and anthropogenic factors on FVC were evaluated with a combination of factor regression and interaction. The results show that:(1)There is a clear spatial heterogeneity in FVC across the Three-River Headwaters region; (2)The natural environmental factors have more impact on FVC spatial distribution than anthropogenic factors;(3)The natural environmental factors have greater impact on FVC spatial distribution than do anthropogenic factors, of which annual precipitation can explain 0.777 of the total variance despite its strongest interaction with other factors; (4) Factors interaction found that the driving explanation system shows a two-factor enhancement, indicating that there is no independent factor from the perspective of the system, and the interaction between annual precipitation and other factors is the strongest; (5)The precipitation gradient affects the degree of explanation of the spatial heterogeneity of FVC in the Three-River Headwaters Region. With an increase in precipitation, the explanatory power of the factors tends to stabilize, and the FVC tends to be more influenced by elevation and temperature in the eastern part of the Three-River Headwaters area where precipitation is higher; (6) The data results also confirm that factor-independent global optimal screening is only an optimal function that simulates the characteristics of the dependent variable, and its explanatory effect is not fully equivalent to the driven explanation of the dependent variable.
2022 Vol. 42 (8): 3903-3912 [Abstract] ( 131 ) [HTML 1KB] [ PDF 2938KB] ( 242 )
3913 Distribution characteristics and utilization evaluation of selenium-rich land resources in Xiong'an New District
ZHOU Ya-long, GUO Zhi-juan, WANG Qiao-lin, WANG Cheng-wen, SONG Yun-tao, LIU Fei
Surface soil samples (0~20cm), bulk crops (wheat seeds) and root soil samples were collected from Xiong'an New District for characterizing the distribution and enrichment of soil selenium through GIS spatial analysis, correlation analysis, etc. Then, the suitability assessment of development and utilization of selenium-rich land resources was carried out with the theory model of niche suitability evaluation. The results show that the surface selenium-rich land in the new area is about 16993hm2; and the soil selenium is mainly in the form of strong organic binding, then in the residue and humic acid binding state, together accounting for more than 87% of the total pool. The proportion of average bioavailable selenium content is relatively small (water-soluble selenium accounts for 4.44%, ion-exchange selenium accounts for 3.43%). The selenium-enriched rate in wheat seed samples is 28.45% and significantly correlated with that in root soil (r=0.77,P<0.01). The content of soil selenium has a significant positive correlation with "signature" soil indicators of sedimentary geomorphological environment, such as the content of Al2O3, Fe2O3, MgO, K2O, soil organic carbon (Corg.), cation exchange capacity (CEC), clay and silt, and negatively correlated with the content of SiO2、Na2O and soil sand (P<0.01). Obviously, the enrichment of soil selenium is mainly affected by Quaternary sedimentary geomorphic environment even though its anomaly could be related to external sources such as irrigation water, chemical fertilizers, atmospheric dry and wet deposition (coal burning and dust reduction). And the niche theory modeling results show that the high-suitability areas (level I) and the moderately suitable areas (level II) are mainly present in Nanzhang and Xiaoli Town of Rongcheng County, Zhaili and Laohetou Town of Anxin County in the northwest of the new area, covering an area of 14397.35hm2, or accounting for 8.13% of the area.
2022 Vol. 42 (8): 3913-3921 [Abstract] ( 151 ) [HTML 1KB] [ PDF 3073KB] ( 240 )
Carbon Emission Control
3922 Carbon emissions assessment of wooden building materials manufactured from a digital and intelligent production line
LI Pei-xian, SONG Guang-han, YANG Xiao-lu, SONG Xiang-nan, LU Yu-jie
In order to understand carbon emissions from wooden building materials produced in digital and intelligent factories and to provide ground references and benchmarks for carbon reduction strategies, a life-cycle assessment (LCA) was conducted in this study to quantify the carbon footprints of main wooden building materials. The results show that the carbon footprints (per unit mass:kg CO2e/kg) for a wood floor tile, a wood door, and a wood door frame are 1.21, 1.26, and 0.47, respectively. The carbon footprints of the floor tile and the door are greater than their domestic counterparts in the literature. The raw materials and production processes are the main sources of carbon emissions for wooden building materials, accounting for 54.74%~77.47% and 18.57%~38.94% of the total carbon emissions, respectively, while the carbon emissions during transportation and waste gas treatment process account for less than 9% of the total carbon emissions. The Monte Carlo simulations show a relatively low uncertainty of the calculated carbon emissions in this study. Digital and intelligent factories could potentially reduce carbon emissions in the future by procuring low-carbon raw materials, optimizing the product designs, improving the energy efficiency of equipment, and using clean energy like solar and wind.
2022 Vol. 42 (8): 3922-3930 [Abstract] ( 163 ) [HTML 1KB] [ PDF 644KB] ( 282 )
3931 Effects and mechanisms of Zinc on nitrous oxide emissions from farmland soil under different fertilization conditions
ZHOU Jin-rong, ZHANG Ting, FENG Lian-jie, JIANG Jing-yan
To understand effects and mechanisms of different Zinc (Zn) application rates (0, 50, 500, 1500 and 5000mg/kg) on nitrous oxide (N2O) emissions from farmland soils under different nitrogen fertilizers (manure and urea), an 80-day simulating incubation experiment was conducted, and urea was added again to all treatments on the day 52 of incubation to explore its long-term effects. The results showed that Zn addition significantly reduced N2O emissions in urea-fertilized soil while enhanced N2O emissions in manure-amended soil in the first fertilization stage (P<0.05) except for the experiment of 50mg/kg Zn with manure which had no significant effect on N2O emissions (P>0.05). In the second fertilization stage, the effects of Zn on N2O emissions were consistent under different nitrogen fertilizers:50mg/kg Zn had no significant effects (P>0.05), 500 and 1500mg/kg Zn significantly promoted N2O emissions, while 5000mg/kg Zn had the opposite effect (P<0.05). At this stage, the ratios of cumulative N2O emissions from the 500, 1500 and 5000mg/kg treatments to the corresponding control were 3.49, 3.13, 0.01 for manure treatments and 2.53, 2.74, 0.04 for urea treatment, respectively, indicating that the effect of Zn was much stronger in manure-amended treatments. The promotion mechanism of 500 and 1500mg/kg Zn could be the Zn-induced increase in the soil NH4+-N and NO3--N contents as well as the abundance ratio of nirS to nosZ, and its control on the genes that are responsible for N2O production and reduction in the denitrification process. Moreover, the 5000mg/kg Zn might impede the transformation progress of NH4+-N to NO3--N in soil, thus reduced N2O emissions.
2022 Vol. 42 (8): 3931-3939 [Abstract] ( 105 ) [HTML 1KB] [ PDF 523KB] ( 223 )
3940 Evaluation and prediction of the synergistic effect of pollution reduction and carbon reduction in Tianjin
LIU Mao-hui, LIU Sheng-nan, LI Jing, SUN Meng, CHEN Kui
To evaluate and predict the synergistic effect of reducing pollution and carbon in Tianjin, the emission reduction elasticity coefficient method was used in this study. Based on the STIRPAT model, the synergistic effect of pollution reduction and carbon reduction in Tianjin during the "14th Five-Year Plan" period and 2026~2060 were predicted by scenario. The results showed that the main emission sources of air pollution equivalent and greenhouse gases were industrial sources. The synergistic effect coefficient of pollution reduction and carbon reduction in Tianjin ranged from 0.11 to 0.26 in 2015~2017, and was less than 0in 2013~2014 and 2018~2020. According to prediction, the synergistic effect coefficient of pollution reduction and carbon reduction in Tianjin was 0.06 during the "14th Five-Year Plan" period and was greater than 0 in 2026~2060 under various scenarios. In 2011~2020, the synergistic effect of pollution reduction and carbon reduction in Tianjin fluctuated and changed, and it was possible to reach the synergistic stage during the "14th Five-Year Plan" period. In order to achieve a high level of synergy of pollution reduction and carbon reduction in Tianjin from 2026 to 2060, several measures need to take, including reasonably control the urbanization rate, the total population and the gross regional product, increasing the proportion of tertiary industry and high technology, and continuously reducing the energy intensity.
2022 Vol. 42 (8): 3940-3949 [Abstract] ( 160 ) [HTML 1KB] [ PDF 442KB] ( 370 )
Environmental Toxicology and Health
3950 Impacts of atmospheric NO2 pollution on cause-specific mortality of different diseases in exposed population in Guangzhou
CAI Dong-jie, YANG Jun, HUANG Lin, CHEN Su-juan, ZHAO Wen-long, DONG Hang, LIN Guo-zhen, WANG Bo-guang
Atmospheric NO2, a major gaseous pollutant, has received increasing attentions due to its high health risk, especially to human cardiopulmonary function. However, current assessments of the health effects of NO2 mainly focused on one single disease. In this study, the generalized additive model (GAM) was used to evaluate impacts of atmospheric NO2 pollution on cause-specific mortality (Relative risk, RR) in exposed population in Guangzhou during 2011~2015, as well as its cumulative lag effects2. Furthermore, the stratified analysis was performed in the cold season (November through April) and the warm season (May to October). The results show that effects of NO2 were observed to be rapid and transient, usually lasting for four days. In lag 0~4 days when the NO2 increased by 10μg/m3, the number of non-accidental deaths increased by 2.18% (RR=1.0218; 95% CI:1.0167, 1.0270) in the full year, and 2.6% (RR=1.0260; 95% CI:1.0191, 1.0328) in the cold season and 0.57% (RR=1.0057; 95% CI:0.9952, 1.0163) in the warm season. The difference in the NO2-induced mortality risks between cold and warm seasons was statistically significant (P=0.002). Among different diseases, NO2 pollution showed the greatest influence on chronic obstructive pulmonary disease. Therefore, atmospheric NO2 pollution is still an important risk to the residents in Guangzhou. And it is necessary to strengthen the control and management of NO2 emissions and implement the early warning of NO2 pollution to protect the public health, particularly during the cold season.
2022 Vol. 42 (8): 3950-3956 [Abstract] ( 162 ) [HTML 1KB] [ PDF 1013KB] ( 267 )
3957 Effects of microplastics on the spread and horizontal gene transfer of antibiotic resistance genes
WU Xiao-jian, SHI Guo-jing, WANG Ying-ying
As an emerging pollutant, microplastics are ubiquitous in different types of environments. The antibiotic resistance genes (ARGs) carried by microplastic biofilms have adverse effects on human health, which has aroused wide concerns. However, the role of microplastics in the process of long migration and horizontal gene transfer of ARGs is still not clear. The environmental impacts of the resistance dissemination caused by microplastics also need further investigation. The current status of microplastic pollutants and the ARGs they carry was summarized. The pathways by which microplastics spread ARGs and the regulation of ARG transfer via microplastics are also compared and discussed. Future research perspectives are proposed to provide possible approaches for solving the problem of antibiotic resistance dissemination by microplastics.
2022 Vol. 42 (8): 3957-3968 [Abstract] ( 262 ) [HTML 0KB] [ PDF 706KB] ( 448 )
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