硅–铁改性生物质炭对水土环境中镉砷的吸附及钝化机制研究  

Adsorption and Passivation Mechanisms of Cadmium and Arsenic Contamination in Water and Soil Environments by Silico-Ferric Modified Biochar

作　　者：李诗怡 茹东周 房友田 田欣 连斌 赵科理[1,2] 李章涛 吴骥子 LI Shiyi;RU Dongzhou;FANG Youtian;TIAN Xin;LIAN Bin;ZHAO Keli;LI Zhangtao;WU Jizi(College of Environmental and Resource Sciences,Zhejiang A&F University,Hangzhou 311300,China;Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province,Zhejiang A&F University,Hangzhou 311300,China;Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province,Zhejiang University of Science and Technology,Hangzhou 310023,China)

机构地区：[1]浙江农林大学环境与资源学院,杭州311300 [2]浙江农林大学浙江省土壤污染生物修复重点实验室,杭州311300 [3]浙江省废弃生物质循环利用与生态处理技术重点实验室,浙江科技大学,杭州310023

出　　处：《土壤学报》2024年第6期1591-1604,共14页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(42207011);国家级大学生创新创业训练项目(202210341022);浙江省自然科学基金项目(LQ22D010009)共同资助。

摘　　要：土壤、水体中共存的镉(Cd)、砷(As)极易通过食物链危害人类健康,是亟待解决的全球性环境问题。通过共沉淀-物理混合法制备新型硅–铁改性生物质炭(CMSMB),并通过Cd、As复合污染水体吸附试验与土壤培养试验探究其修复能力与机理。结果表明,CMSMB对Cd(Ⅱ)、As(Ⅲ)复合污染修复效果优异,最大吸附容量分别为272.73和17.59 mg·g-1,两种元素在CMSMB表面的吸附过程同时存在拮抗和协同作用,其相对强弱取决于溶液中Cd(Ⅱ)和As(Ⅲ)的浓度。拮抗作用主要源于Cd(Ⅱ)、As(Ⅲ)对羟基和芳环表面结合位点的竞争,而协同作用主要通过静电吸附、Cd-As共沉淀和三元表面络合物的形成实现。土壤培养20 d后,CMSMB的添加提高了土壤pH和可溶性有机碳含量,从而促进土壤中有效态Cd浓度的显著降低(降幅64.86%~74.25%),是CMSMB与土壤理化性质变化交互引起的静电吸附、沉淀、络合等机制共同作用的结果。而短期土壤培养下CMSMB对土壤As有效性影响不显著,有效态As浓度仅随培养时间增加而略有降低。综上所述,CMSMB是一种对Cd(Ⅱ)、As(Ⅲ)复合污染水体有着良好修复能力的环境功能材料,其在短期内能实现对复合污染土壤中Cd的钝化和抑制As有效性升高的趋势,可应用于矿尾水、农用地污灌水等镉砷复合污染污水及农用地土壤的修复,但其长期修复能力及修复所包含迁移转化和微生物组学机制,有待进一步探究和验证。【Objective】The coexistence of cadmium(Cd)and arsenic(As)in soil and water has emerged as a critical global environmental concern due to the significant risks it poses to human health through the food chain.To address this pressing issue,a novel silicon-ferric modified biochar(CMSMB)was developed using a co-precipitation-physical mixing method.【Method】The study aimed to comprehensively investigate the remediation capabilities and underlying mechanisms of CMSMB through a series of batch experiments and soil incubation trials in environments contaminated by both Cd and As.【Result】In batch experiments,CMSMB exhibited an impressive maximum adsorption capacity of 272.73 and 17.59 mg·g-1 for Cd(Ⅱ)and As(Ⅲ),respectively.The adsorption processes on the CMSMB surface were intricate,involving a simultaneous interplay of antagonistic and synergistic interactions,and the relative strengths of these interactions were found to be controlled by the concentrations of Cd(Ⅱ)and As(Ⅲ)in the solution.The antagonistic effect primarily originated from the competitive binding of Cd(Ⅱ)and As(Ⅲ)to hydroxyl and aromatic rings.Conversely,the synergistic effect relied on electrostatic adsorption,Cd-As co-precipitation,and the formation of ternary surface complexes.Soil incubation experiments conducted over 20 days revealed significant positive outcomes.The application of CMSMB led to a substantial increase in soil pH and dissolved organic carbon(DOC)content.Consequently,there was a noteworthy decrease(ranging from 64.86%to 74.25%)in the concentration of available Cd in the soil.These changes were attributed to the impact of electrostatic adsorption,precipitation,and complexation resulting from the intricate interplay between CMSMB and alterations in the soil physicochemical properties.However,in the short-term soil incubation,CMSMB exhibited a negligible influence on the bioavailability of As in the soil.The concentration of bioavailable As showed only a slight decline with increasing incubation time which suggests t

关 键 词：重金属 铁改性生物质炭 硅–铁复合材料 吸附机理 原位修复 

分 类 号：X171.5[环境科学与工程—环境科学]