小分子DOM对铁锰二元氧化物吸附氧化As(Ⅲ)的影响机制——基于批试验与DFT计算  

Influence Mechanism of Low Molecule DOM on Adsorption and Oxidation of As(Ⅲ)by Fe-Mn Binary Oxide-Insight from Batch Experiment and DFT Calculation

作　　者：巩嘉铭 谢先军 肖紫怡 GONG Jiaming;XIE Xianjun;XIAO Ziyi(School of Environmental Studies,China University of Geoscience(Wuhan),Wuhan 430078,China)

机构地区：[1]中国地质大学(武汉)环境学院,湖北武汉430078

出　　处：《安全与环境工程》2023年第5期203-212,246,共11页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(42020104005)。

摘　　要：通过铁锰二元氧化物(FMBO)上砷吸附-解吸批试验,结合X射线光电子能谱(XPS)表征和密度泛函理论(DFT)计算探究不同小分子DOM(黄腐酸、天冬氨酸、单宁酸)对FMBO吸附氧化As(Ⅲ)的影响机制。结果表明:3种小分子DOM通过占据吸附位点以及形成DOM-As络合来抑制FMBO吸附As(Ⅲ);3种小分子DOM对FMBO吸附As(Ⅲ)的抑制效果表现为单宁酸>黄腐酸>天冬氨酸;黄腐酸中酚羟基通过As—O共价键与亚砷酸自发络合,抑制了FMBO对亚砷酸的吸附;天冬氨酸中氨基与亚砷酸络合困难,As—N键不易形成,对As(Ⅲ)在FMBO上吸附的影响最小;黄腐酸与单宁酸通过抑制FMBO中Mn(Ⅳ)对As(Ⅲ)的氧化,使矿物表面As(Ⅴ)的比例降低。The effect of different low molecule DOM(fulvic acid,aspartic acid,tannic acid)on the adsorption and oxidation of As(II)on Fe-Mn binary oxide(FMBO)was investigated by adsorption-desorption batch experiment combined with XPS characterization and DFT(density functional theory)calculation.The re-sults are as follows:DOM inhibits As(Ⅲ)adsorption on FMBO by occupying adsorption sites and forming DOM-As complexation;the inhibitory effect of three low molecule DOM on the adsorption of As(Ⅲ)by FMBO was tannic acid>fulvic acid>aspartic acid;the phenolic hydroxyl group in fulvic acid spontaneously forms complex with arsenite through As-O covalent bond to inhibit the adsorption of arsenite on FMBO;the aspartic acid,which has the weakest inhibitory effect on the adsorption of As(Ⅲ)on FMBO,is difficult to spontaneously form complex with arsenite by AS-N bond.Fulvic acid and tannic acid inhibit the oxida-tion of Mn(IV)to As(Ⅲ)in FMBO,and the proportion of As(V)on FMBO surface decreases.

关 键 词：小分子DOM As(Ⅲ) 铁锰二元氧化物 吸附-解吸批试验 DFT计算 

分 类 号：X53[环境科学与工程—环境工程]