Study on the Phosphorus Removal Mechanism and Application Potential of Fe/N-modified biochar
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Yiming Gao
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Phosphorus is a key nutrient limiting the primary productivity of lakes, but its excessive input has become the main cause of eutrophication. To address both phosphorus pollution in water bodies and the need for resource recovery, this paper developed an iron-nitrogen co-modified biochar (Fe/N-BC) using agricultural wastes as the raw material. The modified biochar was produced through the co-pyrolysis of FeCl₃ and urea and achieved improvements in both structure and function. Its structure was characterized using BET and FTIR techniques. Its phosphate removal performance and adsorption behavior were investigated through batch adsorption experiments and were analyzed by kinetic and isothermal models, respectively. The results showed that Fe/N-BC possessed a high specific surface area (916.5 m²/g) and a well-developed microporous structure, with a maximum phosphorus adsorption capacity of 31.34 mg/g, which outperformed that of raw biochar and attapulgite (a control material). The adsorption process conforms to a pseudo-second-order kinetic model, indicating chemisorption as the dominant mechanism. FTIR analysis revealed the formation of Fe–O–P bonds and hydrogen bonding interactions involving pyrrolic-N, showing a synergistic adsorption system. At pH 5 and with coexisting Cl/SO₄²- ions, Fe/N-BC still showed good adaptability and resistance to interference. Furthermore, in actual lake water, the material maintained stable phosphorus removal performance, proving its strong environmental adaptability and potential for engineering applications. The Fe/N co-modification in this study strategy helps deepen the understanding of phosphorus adsorption and build a practical foundation for creating more effective materials to control eutrophication in water bodies.
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Authors
Yiming Gao
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Cheng, N., Wang, B., Wu, P., Lee, X., Xing, Y., Chen, M., & Gao, B. (2021). Adsorption of emerging contaminants from water and wastewater by modified biochar: A review. Environmental Pollution, 273, 116448. https://doi.org/10.1016/j.envpol.2021.116448
Cui, Q., Xu, J., Wang, W., Tan, L., Cui, Y., Wang, T., Li, G., She, D., & Zheng, J. (2020). Phosphorus recovery by core-shell γ-Al₂O₃/Fe₃O₄ biochar composite from aqueous phosphate solutions. Science of The Total Environment, 729, 138892. https://doi.org/10.1016/j.scitotenv.2020.138892
Hou, L., Liang, Q., & Wang, F. (2020). Mechanisms that control the adsorption–desorption behavior of phosphate on magnetite nanoparticles: The role of particle size and surface chemistry characteristics. RSC Advances, 10(4), 2378–2388. https://doi.org/10.1039/C9RA08517C
Huang, R., Lu, X., Li, W., Xiong, J., & Yang, J. (2024). Progress on the adsorption characteristics of nZVI and other iron-modified biochar for phosphate adsorption in water bodies. Circular Economy, 3(4), 100112. https://doi.org/10.1016/j.cec.2024.100112
Li, B., Jing, F., Hu, Z., Liu, Y., Xiao, B., & Guo, D. (2021). Simultaneous recovery of nitrogen and phosphorus from biogas slurry by Fe-modified biochar. Journal of Saudi Chemical Society, 25(4), 101213. https://doi.org/10.1016/j.jscs.2021.101213
Li, S., Ma, X., Ma, Z., Dong, X., Wei, Z., Liu, X., & Zhu, L. (2021). Mg/Al-layered double hydroxide modified biochar for simultaneous removal phosphate and nitrate from aqueous solution. Environmental Technology & Innovation, 23, 101771. https://doi.org/10.1016/j.eti.2021.101771
Li, X., & Shi, J. (2022). Simultaneous adsorption of tetracycline, ammonium and phosphate from wastewater by iron and nitrogen modified biochar: Kinetics, isotherm, thermodynamic and mechanism. Chemosphere, 293, 133574. https://doi.org/10.1016/j.chemosphere.2022.133574
Li, Y., He, X., Hu, H., Zhang, T., Qu, J., & Zhang, Q. (2018). Enhanced phosphate removal from wastewater by using in situ generated fresh trivalent Fe composition through the interaction of Fe(II) on CaCO3. Journal of Environmental Management, 221, 38–44. https://doi.org/10.1016/j.jenvman.2018.05.018
Li, Y., Xu, R., Wang, H., Xu, W., Tian, L., Huang, J., Liang, C., & Zhang, Y. (2022). Recent advances of biochar-based electrochemical sensors and biosensors. Biosensors, 12(6), 377. https://doi.org/10.3390/bios12060377
Li, Z., Liu, X., & Wang, Y. (2020). Modification of sludge-based biochar and its application to phosphorus adsorption from aqueous solution. Journal of Material Cycles and Waste Management, 22(1), 123–132. https://doi.org/10.1007/s10163-019-00921-6
Lin, F., Wang, L., Dai, X., Man, Z., Meng, Y., Chu, D., Yang, Y., Wang, W., Xiao, H., & Wang, K. (2024). Catalytic fixation of hydrogen sulfide over CuO–CaCO₃ co-impregnated tea stalk-derived biochar. Journal of Environmental Chemical Engineering, 12(5), 113320. https://doi.org/10.1016/j.jece.2024.113320
Liu, S., Zhao, C., Wang, Z., Ding, H., Deng, H., Yang, G., Li, J., & Zheng, H. (2020). Urea-assisted one-step fabrication of a novel nitrogen-doped carbon fiber aerogel from cotton as metal-free catalyst in peroxymonosulfate activation for efficient degradation of carbamazepine. Chemical Engineering Journal, 386, 124015. https://doi.org/10.1016/j.cej.2020.124015
Luo, D., Wang, L., Nan, H., Cao, Y., Wang, H., Kumar, T. V., & Wang, C. (2023). Phosphorus adsorption by functionalized biochar: A review. Environmental Chemistry Letters, 21(1), 497–524. https://doi.org/10.1007/s10311-022-01519-5
Mei, Y., Xu, J., Zhang, Y., Li, B., Fan, S., & Xu, H. (2021). Effect of Fe–N modification on the properties of biochars and their adsorption behavior on tetracycline removal from aqueous solution. Bioresource Technology, 325, 124732. https://doi.org/10.1016/j.biortech.2021.124732
Pan, F., Wei, H., Huang, Y., Song, J., Gao, M., Zhang, Z., Teng, R., & Jing, S. (2024). Phosphorus adsorption by calcium chloride-modified buckwheat hulls biochar and the potential application as a fertilizer. Journal of Cleaner Production, 444, 141233. https://doi.org/10.1016/j.jclepro.2024.141233
Ping, Q., Zhang, B., Zhang, Z., Lu, K., & Li, Y. (2023). Speciation analysis and formation mechanism of iron-phosphorus compounds during chemical phosphorus removal process. Chemosphere, 310, 136852. https://doi.org/10.1016/j.chemosphere.2022.136852
Qian, L., Zhonghua, Y., Wei, Y., Minghui, Y., Fengpeng, B., Yao, Y., & Yufeng, R. (2023). Tracing the sources and transport of the total phosphorus in the upper Yangtze River. Ecological Informatics, 77, 102230. https://doi.org/10.1016/j.ecoinf.2023.102230
Shin, H., Tiwari, D., & Kim, D.-J. (2020). Phosphate adsorption/desorption kinetics and P bioavailability of Mg-biochar from ground coffee waste. Journal of Water Process Engineering, 37, 101484. https://doi.org/10.1016/j.jwpe.2020.101484
Singh, J., Bhattu, M., Liew, R. K., Verma, M., Brar, S. K., Bechelany, M., & Jadeja, R. (2025). Transforming rice straw waste into biochar for advanced water treatment and soil amendment applications. Environmental Technology & Innovation, 37, 103932. https://doi.org/10.1016/j.eti.2024.103932
United Nations Environment Programme. (2024, January 24). What is phosphorus and why are concerns mounting about its environmental impact? UNEP. https://www.unep.org/news-and-stories/story/what-phosphorus-and-why-are-concerns-mounting-about-its-environmental-impact
Wu, B., Wan, J., Zhang, Y., Pan, B., & Lo, I. M. C. (2020). Selective Phosphate Removal from Water and Wastewater using Sorption: Process Fundamentals and Removal Mechanisms. Environmental Science & Technology, 54(1), 50–66. https://doi.org/10.1021/acs.est.9b05569
Xiang, X., Guo, L., Wu, X., Ma, X., & Xia, Y. (2012). Urea formation from carbon dioxide and ammonia at atmospheric pressure. Environmental Chemistry Letters, 10(3), 295–300. https://doi.org/10.1007/s10311-012-0366-2
Yang, J., Zhou, L., Zhao, L., Zhang, H., Yin, J., Wei, G., & Yu, C. (2011). A designed nanoporous material for phosphate removal with high efficiency. Journal of Materials Chemistry, 21(8), 2489–2494. https://doi.org/10.1039/C0JM02718A
Yi, Y., Wang, X., Ma, J., & Ning, P. (2021). Fe(III) modified Egeria najas-driven biochar for highly improved reduction and adsorption performance of Cr(VI). Powder Technology, 388, 485–495. https://doi.org/10.1016/j.powtec.2021.04.066
Zhou, X., Liu, Y., Zhou, J., Guo, J., Ren, J., & Zhou, F. (2018). Efficient removal of lead from aqueous solution by urea-functionalized magnetic biochar: Preparation, characterization and mechanism study. Journal of the Taiwan Institute of Chemical Engineers, 91, 457–467. https://doi.org/10.1016/j.jtice.2018.04.018
Zubrowska-Sudol, M., & Walczak, J. (2015). Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge. Water Research, 76, 10–18. https://doi.org/10.1016/j.watres.2015.02.041
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