碱/抗坏血酸活化分子氧氧化水中As(Ⅲ)  

Oxidation of As(Ⅲ) in water by alkaline/ascorbic acid activated molecular oxygen

作　　者：王震华 罗涛 李进军[1] 吴峰[1] WANG Zhenhua;LUO Tao;LI Jinjun;WU Feng(School of Resource and Environmental Sciences,Wuhan University,Wuhan 430079)

机构地区：[1]武汉大学资源与环境科学学院,武汉430079

出　　处：《环境科学学报》2022年第7期225-233,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.21777125)。

摘　　要：研究了碱/抗坏血酸(H_(2)A)活化分子氧体系(碱/H_(2)A体系)氧化水中三价砷(As(Ⅲ))的过程与机理.考察了pH、H_(2)A浓度、As(Ⅲ)初始浓度、水中常见阴离子(Cl^(-)、NO_(3)^(-)、HCO_(3)-)和有机质富里酸对As(Ⅲ)氧化效率的影响,通过自由基抑制实验及电子自旋共振(ESR)鉴定了体系中的活性氧物质(ROS),并采用液相色谱-质谱分析技术鉴定了H_(2)A的降解产物.结果表明,在pH=9~12范围内,pH值越高,As(Ⅲ)氧化速率越快;pH=10条件下,随着H_(2)A浓度从0.05 mmol·L^(-1)增加到1 mmol·L^(-1),反应1 h后,As(Ⅲ)氧化率从24%增加至92%.机理研究结果表明,H_(2)O_(2)是碱/H_(2)A活化分子氧体系中氧化As(III)的主要ROS,它主要来自碱性条件下H_(2)A与分子氧的单电子或双电子反应,同时,体系中H_(2)A也发生了氧化性降解.碱/H_(2)A体系可用于含砷废水的预处理,并与离子交换吸附方法联合,实现高效除砷.The processes and mechanisms of alkaline/ascorbic acid(H_(2)A)activated molecular oxygen system(alkaline/H_(2)A system)to oxidize trivalent arsenic(As(Ⅲ))in water was systematically studied in this work.The effects of pH,H_(2)A concentration,initial concentration of As(Ⅲ),common anions(Cl−,NO_(3)−,HCO_(3)−)and organic matter(Fulvic acid)in water on the oxidation efficiency of As(Ⅲ)were investigated.Reactive oxygen species(ROS)in the system were identified by free radical inhibition assay and electron spin resonance(ESR).H_(2)A degradation products were identified by liquid chromatography-mass spectrometry.The results show that in the range of pH 9~12,the oxidation of As(Ⅲ)is faster at higher pH.The oxidation efficiency of As(Ⅲ)increased from 24%to 92%with the increase of H_(2)A concentration from 0.05 mmol·L^(-1)to 1 mmol·L^(-1)at pH 10 for 1 h reaction;Mechanism study revealed that H_(2)O_(2)is the main ROS for the oxidation of As(Ⅲ)in the alkaline/H_(2)A activated molecular oxygen system,which mainly comes from the reaction of H_(2)A with molecular oxygen through one or two electron reaction at alkaline conditions,accompanying with the oxidative degradation of H_(2)A.The alkaline/H_(2)A system can be used for the pretreatment of arsenic-containing wastewater and can combined with ion exchange adsorption methods to achieve high arsenic removal efficiency.

关 键 词：三价砷As(Ⅲ) 抗坏血酸(H_(2)A) 碱 过氧化氢 氧化效率 活性氧物质(ROS) 

分 类 号：X703[环境科学与工程—环境工程]