腐殖质对电絮凝体系中As(Ⅲ)氧化去除的影响机制  

Mechanism of influence of humic acid on oxidation removal of As(Ⅲ)in electroflocculation system

作　　者：赵凤怡 童曼[1] 张娜[1] 蔡其正 ZHAO Fengyi;TONG Man;ZHANG Na;CAI Qizheng(State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Wuhan),Wuhan 430078,China)

机构地区：[1]中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉430078

出　　处：《安全与环境工程》2025年第1期244-255,共12页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(42277072)。

摘　　要：电絮凝技术可以通过二价铁[Fe(Ⅱ)]的氧化沉淀机制高效氧化去除地下水中的As(Ⅲ)。天然有机质(NOM)广泛存在于高砷地下水中,可能通过络合、电子穿梭、竞争吸附位点等多种途径影响Fe(Ⅱ)的氧化沉淀,但目前天然有机质对电絮凝体系中As(Ⅲ)氧化去除的影响规律和机制尚不清楚。以腐殖酸(humic acid,HA)作为天然有机质的代表,研究了腐殖质对电絮凝体系中As(Ⅲ)氧化去除的影响规律和机制。结果表明:(1)HA可以促进电絮凝体系中Fe(Ⅱ)的氧化沉淀和As(Ⅲ)的氧化去除,且HA浓度越高,促进效果越显著;(2)在不同pH值(6.0、6.5、7.0、7.5)以及不同电解质环境下,HA对Fe(Ⅱ)氧化沉淀和As(Ⅲ)氧化去除的影响有显著的差异,pH值越低HA促进As(Ⅲ)氧化去除的效果越显著,在Na2SiO3电解质环境下HA对As(Ⅲ)的氧化去除作用最为显著;(3)HA促进电絮凝体系中As(Ⅲ)氧化去除的机制是通过加速水相Fe(Ⅱ)的氧化促进Fe的沉淀,从而使Fe(Ⅱ)的氧化沉淀过程主导As(Ⅲ)的氧化和去除。研究结果可为高砷地下水修复提供理论指导。As(Ⅲ)in groundwater can be efficiently oxidized and removed by electroflocculation technology through the oxidation precipitation mechanism of bivalent iron.Natural organic matter widely exists in groundwater with high arsenic content,which may affect the oxidation precipitation of Fe(Ⅱ)through various ways such as complexation,electron shuttle and competitive adsorption sites.However,the rule and mechanism of natural organic matter on the oxidation removal of As(Ⅲ)in electroflocculation system are still unclear.Taking humic acid(HA)as the representative of natural organic matter,this paper studies the rule and mechanism of the influence of humic acid on the oxidation removal of As(Ⅲ)in the electroflocculation arsenic removal system.The results are as follows:①HA can promote the oxidation precipitation of Fe(Ⅱ)and the oxidation removal of As(Ⅲ)in the electroflocculation arsenic removal system,and the higher the concentration of HA,the more significant the promotion effect;②The effect of HA on oxidation precipitation of Fe(Ⅱ)and oxidation removal of As(Ⅲ)is significantly different under different pH values(6.0,6.5,7.0,7.5)and different electrolyte environments.The lower the pH,the more significant the effect of HA on oxidation removal of As(Ⅲ).Under the environment of Na2SiO3 electrolyte,HA has the most significant oxidation removal effect on As(Ⅲ);③The mechanism by which HA promotes the oxidation and removal of As(Ⅲ)in the electroflocculation system is to promote the precipitation of Fe by accelerating the oxidation of aqueous phase Fe(Ⅱ),so that the oxidation and precipitation process of Fe(Ⅱ)dominates the oxidation and removal of As(Ⅲ).The results can provide theoretical guidance for the remediation of groundwater with high arsenic content.

关 键 词：高砷地下水修复 电絮凝技术 天然有机质(NOM) Fe(Ⅱ)的氧化沉淀 As(Ⅲ)的氧化去除 

分 类 号：X52[环境科学与工程—环境工程]