施氏矿物和水铁矿对砷(Ⅲ)吸附性能的比较研究  

Comparison of arsenite adsorption by Schwertmannite and ferrihydrite

作　　者：王威 冯坤[1] 王晓萌 王茹 梁剑茹[1] 周立祥[1] WANG Wei;FENG Kun;WANG Xiaomeng;WANG Ru;LIANG Jianru;ZHOU Lixiang(College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学资源与环境科学学院,江苏南京210095

出　　处：《南京农业大学学报》2020年第6期1116-1123,共8页Journal of Nanjing Agricultural University

基　　金：国家自然科学基金项目(41977338,21637003)。

摘　　要：[目的]本文主要探究施氏矿物(Sch)和水铁矿(Fh)对As(Ⅲ)的吸附差异。[方法]分别使用生物和化学方法合成施氏矿物和水铁矿,通过吸附动力学和吸附等温模型,比较2种矿物对As(Ⅲ)的吸附效果,同时探究pH值、共存离子对2种矿物吸附As(Ⅲ)的影响。[结果]施氏矿物的吸附速率常数k1为0.0139 min-1,远大于水铁矿的0.0019 min-1,且吸附过程符合伪一级动力学,说明施氏矿物对As(Ⅲ)吸附是一个快速的过程。吸附等温模型拟合结果表明,2种矿物对As(Ⅲ)的吸附主要为单层吸附。在中性条件下,施氏矿物对As(Ⅲ)的吸附量为165.73 mg·g^-1,大于水铁矿的133.50 mg·g^-1。施氏矿物吸附的最佳pH值为6~12,而水铁矿的为6~8。共存离子对水铁矿吸附过程影响更小。水铁矿吸附As(Ⅲ)的主要机制为表面羟基的络合配位作用,而施氏矿物对As(Ⅲ)的吸附主要是As(Ⅲ)与矿物表面金属羟基的表面络合、As(Ⅲ)与矿物表面及隧道结构内SO4^2-的配位体交换。[结论]施氏矿物对As(Ⅲ)的吸附性能优于水铁矿,是一种高效的修复砷污染水体的吸附材料。[Objectives]The purpose of this paper was to explore the difference in adsorption of As(Ⅲ)between Schwertmannite(Sch)and ferrihydrite(Fh).[Methods]The Sch and Fh were synthesized by a biological and chemical method,respectively.The adsorption effects of As(Ⅲ)on the two minerals were compared through adsorption kinetics and adsorption isotherm models.The effects of pH and coexisting ions on the adsorption of As(Ⅲ)by two minerals were also investigated.[Results]The adsorption rate constant(k1)of Sch was 0.0139 min-1,which was much larger than that of Fh(0.0019 min-1).The adsorption process for Sch followed pseudo-first-order kinetic,indicating that As(Ⅲ)adsorption was a fast process.The fitting results by the two adsorption isotherm models showed that the adsorption of As(Ⅲ)mainly occurred on minerals’surface.Under neutral conditions,the adsorption capacity of As(Ⅲ)by Sch was 165.73 mg·g^-1,which was greater than that of Fh(133.50 mg·g^-1).Further studies found that the optimal pH range for Sch adsorption was 6-12,and 6-8 for Fh.However,the presence of coexisting ions produced negligible impact on the adsorption process by Fh.The main mechanism for As(Ⅲ)adsorption by Fh was the complex coordination of surface hydroxyl groups,while As(Ⅲ)adsorption by Sch was mainly the surface complexation of As(Ⅲ)with metal hydroxyl groups on the surface of minerals,As(Ⅲ)exchange with SO4^2- on the surface of minerals and in the tunnel structure.[Conclusions]The adsorption performance of Sch to As(Ⅲ)was better than that of Fh.Sch was a high-efficiency repair material for arsenic polluted water.

关 键 词：施氏矿物 水铁矿 As(Ⅲ) 吸附 

分 类 号：X703[环境科学与工程—环境工程]