Abstract：In this paper, the adsorption characteristics of phosphate by sludge biochar (SDBC) were investigated with batch equilibrium method using SDBC prepared from residual sludge (RS) of a wastewater treatment plant. The effects of factors such as dosage of SDBC and pH of solution on phosphate adsorption by SDBC were investigated, and the conditions affecting phosphate adsorption were optimized by response surface methodology (RSM). The mechanism of phosphate adsorption by SDBC was investigated by combining the experimental results with the characterization data. The results showed that the kinetics of phosphate adsorption on SDBC conformed to the Elovich (R2=0.984) equation, which indicated that the phosphate adsorption on SDBC was a non-homogeneous diffusion process with multiple reactions acting together. The Langmuir (R2=0.980) and Langmuir-Freundlich (R2=0.979) equations could well describe the phosphate adsorption on SDBC, and the maximum adsorption capacity estimated from the Langmuir equation was 4.508mg/g. The Langmuir-Freundlich model was fitted with a small homogeneous phase index n (1.143), indicating that the adsorption sites on SDBC were not uniformly distributed, and there were interaction forces between SDBC and phosphate. The optimal initial pH value for phosphate adsorption on SDBC is 4.0 ~ 5.0. The optimal dosage for phosphate adsorption on SDBC is 8g/L. The optimum conditions for phosphate adsorption by SDBC were obtained by RSM analysis with a dosage of 5g/L, an initial phosphate concentration of c0 of 10mg/L, and a pH of 5.0. The possible mechanisms of phosphate adsorption by SDBC included electrostatic adsorption, co-precipitation, replacement, ligand exchange, and pore filling.
[1] 马锋锋,赵保卫,钟金魁,等.牛粪生物炭对磷的吸附特性及其影响因素研究[J]. 中国环境科学, 2015,35(4):1156-1163. Ma F F, Zhao B W, Zhong J K, et al. Characteristics phosphate adsorption onto biochars derived from dairy manure and its influencing factors[J]. China Environmental Science, 2015,35(4):1156-1163. [2] Schott C, Yan L W, Gimbutyte U, et al. Enabling efficient phosphorus recovery from cow manure:Liberation of phosphorus through acidification and recovery of phosphorus as calcium phosphate granules[J]. Chemical Engineering Journal, 2023,460:141695. [3] Tang A, Wang Q, Wan H, et al. Phosphorus biorecovery from wastewater contaminated with multiple nitrogen species by a bacterial consortium[J]. Bioresource Technology, 2023,381:129082. [4] Shrestha R, Ban S, Devkota S, et al. Technological trends in heavy metals removal from industrial wastewater:A review[J]. Journal of Environmental Chemical Engineering, 2021,9(4):105688. [5] Borges B, Strauss M, Camelo P A, et al. Re-use of sugarcane residue as a novel biochar fertiliser-Increased phosphorus use efficiency and plant yield[J]. Journal of Cleaner Production, 2020,262:121406. [6] Yin Q Q, Ren H P, Wang R K, et al. Evaluation of nitrate and phosphate adsorption on Al-modified biochar:Influence of Al content[J]. Science of the Total Environment, 2018,631-632:895-903. [7] He X M, Zhang T, Ren H Q, et al. Phosphorus recovery from biogas slurry by ultrasound/H2O2digestion coupled with HFO/biochar adsorption process[J]. Waste Management, 2017,60:219-229. [8] Li R H, Wang J J, Zhou B Y, et al. Simultaneous capture removal of phosphate, ammonium and organic substances by MgO impregnated biochar and its potential use in swine wastewater treatment[J]. Journal of Cleaner Production, 2017,147:96-107. [9] Li R H, Wang J J, Zhang Z Q, et al. Recovery of phosphate and dissolved organic matter from aqueous solution using a novel CaO-MgO hybrid carbon composite and its feasibility in phosphorus recycling[J]. Science of the Total Environment, 2018,642:526-536. [10] 马锋锋,赵保卫,刁静茹,等.磁性生物炭对水体中对硝基苯酚的吸附特性[J]. 中国环境科学, 2019,39(1):170-178. Ma F F, Zhao B W, Diao J R, et al. Adsorption characteristics of p-nitrophenol removal by magnetic biochar[J]. China Environmental Science, 2019,39(1):170-178. [11] Sewu D D, Boakye P, Woo S H. Highly efficient adsorption of cationic dye by biochar produced with Korean cabbage waste[J]. Bioresource Technology, 2017,224:206-213. [12] Huang Q, Song S, Chen Z, et al. Biochar-based materials and their applications in removal of organic contaminants from wastewater:state-of-the-art review[J]. Biochar, 2019,1(1):45-73. [13] Trakal L, Veselska V, Safarik I, et al. Lead and cadmium sorption mechanisms on magnetically modified biochars[J]. Bioresource Technology, 2016,203:318-324. [14] Chen Y D, Wang R P, Duan X G, et al. Production, properties, and catalytic applications of sludge derived biochar for environmental remediation[J]. Water Research, 2020,187:116390. [15] Wu B R, Dai X H, Chai X L. Critical review on dewatering of sewage sludge:Influential mechanism, conditioning technologies and implications to sludge re-utilizations[J]. Water Research, 2020,180:115912. [16] 杨育红,寇丽栋,范庆峰,等.镁改性污泥基生物炭去除水中磷和抗生素[J]. 中国环境科学, 2022,42(9):4137-4144. Yang Y H, Kou L D, Fan C Q, et al. Removal of phosphate and antibiotics by magnesium modified sludge-derived biochar[J]. China Environmental Science, 2022,42(9):4137-4144. [17] Kończak M, Huber M. Application of the engineered sewage sludge-derived biochar to minimize water eutrophication by removal of ammonium and phosphate ions from water[J]. Journal of Cleaner Production, 2022,331:129994. [18] Xue J B, Wang H X, Li P, et al. Efficient reclaiming phosphate from aqueous solution using waste limestone modified sludge biochar:Mechanism and application as soil amendments[J]. Science of The Total Environment, 2021,799:149454. [19] Yousaf B, Liu G J, Abbas Q, et al. Operational control on environmental safety of potentially toxic elements during thermal conversion of metal-accumulator invasive ragweed to biochar[J]. Journal of Cleaner Production, 2018,195(SEP.10):458-469. [20] Peng G, Jiang S, Wang Y, et al. Synthesis of Mn/Al double oxygen biochar from dewatered sludge for enhancing phosphate removal[J]. Journal Cleaner Production, 2020,251:119725. [21] 吴嘉煦,李凯,孙鑫,等.载镧酒糟污泥生物炭对磷的吸附性能及机理[J]. 环境工程学报, 2022,16(12):3884-3894. Wu J X, Li K, Sun L, et al.Fabrication of La-LBCZ composites for phosphate removal:Adsorption performance and mechanism[J]. Chinese Journal of Environmental Engineering, 2022,16(12):3884- 3894. [22] Zhang L, Liu J, Guo X. Investigation on mechanism of phosphate removal on carbonized sludge adsorbent[J]. Journal of Environmental Sciences, 2018,64:335-344. [23] Mierzwa-Hersztek M, Gondek K, Klimkowicz-Pawlas A, et al. Sewage sludge biochars management-Ecotoxicity, mobility of heavy metals, and soil microbial biomass[J]. Environmental Toxicology and Chemistry, 2018,37(4):1197-1207. [24] 张鑫.污泥生物炭环境风险评价及其对灰钙土热物理性质的影响研究[D]. 兰州:兰州交通大学, 2020. Zhang X. Environmental risk assessment of sewage sludge biochar and its effect on thermophysical properties of sierozem[D]. Lanzhou:Lanzhou Jiaotong University, 2020. [25] Tang X, Lei Y, Yu C, et al. Highly-efficient degradation of organic pollutants by oxalic acid modified sludge biochar:Mechanism and pathways[J]. Chemosphere, 2023,325:138409. [26] Li J, Cao L, Li B, et al. Utilization of activated sludge and shell wastes for the preparation of Ca-loaded biochar for phosphate removal and recovery[J]. Journal of Cleaner Production, 2023,382:135395. [27] Rangabhashiyam S, Lins PVD, Oliveira L, et al. Sewage sludge- derived biochar for the adsorptive removal of wastewater pollutants:A critical review[J]. Environment Pollution, 2022,293:118581. [28] Yao B, Luo Z R, Du S Z, et al. Sustainable biochar/MgFe(2)O4 adsorbent for levofloxacin removal:Adsorption performances and mechanisms[J]. Bioresource Technology, 2021,340:125698. [29] Fu X X, Wang P, Wu J D, et al. Hydrocotyle vulgaris derived novel biochar beads for phosphorus removal:static and dynamic adsorption assessment[J]. Journal of Environmental Chemical Engineering, 2022, 10(4):108177. [30] 王雯婧.稀土镧改性沸石的制备及对水中氮、磷吸附性能的研究[D]. 沈阳:沈阳农业大学, 2023. Wang W J.Preparation of rare earth lanthanum modified zeolite and its adsorption properties for N and P in water[D]. Shenyang:Shenyang Agricultural University, 2023. [31] Liu M J, Li R H, Wang J W, et al. Recovery of phosphate from aqueous solution by dewatered dry sludge biochar and its feasibility in fertilizer use[J]. Science of the Total Environment, 2022,814:152752. [32] Li M, Tang Y, Lu X Y, et al. Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation[J]. Water Research, 2018,140(sep.1):90-99. [33] 王彤彤,崔庆亮,王丽丽,等.Al改性柠条生物炭对P的吸附特性及其机制[J]. 中国环境科学, 2018,38(6):2210-2222. Wang T T, Cui Q L, Wang L L, et al. Adsorption characteristics and mechanism of phosphate from aqueous solutions on Al modification biochar produced from Caragana Korshinskii[J]. China Environmental Science, 2018,38(6):2210-2222.
