摘要
生物炭吸附是解决水中磷酸盐超标的有效手段,金属负载有助于提升生物炭对磷酸盐的吸附量。本研究将铁负载在生物炭表面进行改性,结果表明当生物炭和浓度为0.05 mol/L的FeCl_(3)溶液以1∶10的质量体积比浸泡时,对水中磷酸盐的去除效果最佳,吸附量相较于原始生物炭提升了1.6倍;当投加量为1.0 g,pH为3.0~11.0时,对浓度为15 mg/L,体积为150 mL的磷酸盐吸附去除率可达96.51%。利用SEM、BET、FTIR、XRD和XPS对改性前后生物炭的表面形貌、孔径分布、表面官能团、负载金属的晶型和反应前后的官能团的变化等进行了系统的分析,结果表明生物炭为微孔-介孔复合材料,表面的铁主要以Fe_(2)O_(3)和Fe_(3)O_(4)的形式存在。通过不同操作条件的影响测试表明,溶液pH对磷酸盐的去除几乎无影响,在pH为3~11的范围内磷酸盐去除率均保持75%以上。共存阴离子对磷酸盐的去除影响较大,且随着阴离子浓度的提高,磷酸盐的去除率不断降低。并对改性生物炭的磷酸盐的吸附动力学曲线和等温吸附线等进行了测试。改性生物炭吸附磷酸盐的过程更符合拟二级动力学模型和Freundlich模型,表明铁改性生物炭对磷酸盐的吸附过程是以化学吸附为主同时物理吸附参与的多层吸附过程。结果表明,铁改性生物炭对水中磷酸盐的去除具有较好的应用前景,为开展农业废弃物的回收与资源化利用提供了理论支撑。
Biochar adsorption is an effective approach to addressing excessive phosphate concentrations in water.Metal modification enhances the phosphate adsorption capacity of biochar.In this study,iron was loaded onto biochar surfaces for modification.Results showed that when biochar and 0.05 mol/L iron(III)chloride(FeCl_(3))solution were mixed at a solid-to-liquid ratio of 1:10(mass/volume),the modified biochar exhibited the optimal phosphate removal efficiency in aqueous solutions,with an adsorption capacity 1.6-fold higher than that of unmodified biochar.At a modified biochar dosage of 1.0 g and solution pH of 3.0~11.0,the adsorption removal rate of phosphate(initial concentration:15 mg/L,solution volume:150 mL)reached 96.51%.SEM,BET,FTIR,XRD,and XPS were used to systematically characterize the biochar's surface morphology,pore size distribution,surface functional groups,crystal structure of loaded metals,and changes in functional groups before and after adsorption.Results indicated that the modified biochar was a composite material with both micropores and mesopores,and iron on its surface primarily existed as iron(III)oxide(Fe_(2)O_(3))and iron(II,III)oxide(Fe_(3)O_(4)).Tests on the effects of different operating conditions revealed that solution pH had little impact on phosphate removal,with the removal rate remaining above 75%across the pH range of 3~11.In contrast,coexisting anions significantly affected phosphate removal,with the phosphate removal rate decreasing as anion concentration increased.The phosphate adsorption kinetics and isotherms of the modified biochar were determined;phosphate adsorption by the modified biochar was better fitted by the pseudo-second-order kinetic model and Freundlich isotherm model.This indicates that iron-modified biochar adsorbs phosphate via a multi-layer adsorption process dominated by both chemical and physical adsorption.The results indicate that iron-modified biochar has good potential for removing phosphates from water,providing theoretical support for the recycling and resource utilization of agricultural waste.
作者
寇文静
李昂
吴雷祥
邢璇
韩帅
周璇
KOU Wenjing;LI Ang;WU Leixiang;XING Xuan;HAN Shuai;ZHOU Xuan(College of Materials Science and Engineering,Hebei University of Engineering,Handan 056038,China;China Institute of Water Resources and Hydropower Research,Beijing 100038,China;College of Life and Environmental Sciences,Minzu University of China,Beijing 100081,China)
出处
《水处理技术》
北大核心
2026年第3期80-86,92,共8页
Technology of Water Treatment
基金
国家重点研发项目(2023YFC3207802)
国家重点研发计划(2023YFC3208702)
中央部门预算项目(WE0161A072024)。
