碳酸氢盐促进S(IV)-Mn(Ⅱ)体系氧化As(Ⅲ)  

Bicarbonate promotes the oxidation of As(Ⅲ)by S(IV)-Mn(Ⅱ)system

作　　者：曹敏 孟子贺 宋宝东[1] 吴松海[1] 韩煦[1] CAO Min;MENG Zihe;SONG Baodong;WU Songhai;HAN Xu(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China;China Institute for Radiation Protection,Taiyuan 030006,China)

机构地区：[1]天津大学化工学院,天津300350 [2]中国辐射防护研究所,太原030006

出　　处：《化学工业与工程》2024年第4期88-96,共9页Chemical Industry and Engineering

基　　金：国家自然科学基金(51878449)。

摘　　要：基于亚硫酸盐[S(IV)]的高级氧化工艺由于其低成本的优点引起了越来越多的关注。研究了在碳酸氢盐(HCO_(3)^(-))存在下,过渡金属Mn(Ⅱ)激活S(IV)的体系对高砷地下水中As(Ⅲ)的氧化效果和机理。结果表明,S(IV)-HCO_(3)^(-)-Mn(Ⅱ)体系中HCO_(3)^(-)的存在明显促进了As(Ⅲ)的氧化。动力学实验表明,S(IV)和Mn(Ⅱ)浓度增加都会促进As(Ⅲ)氧化,但过高浓度反而会抑制氧化过程;pH值对体系氧化性能的影响主要是S (IV)和Mn (Ⅱ)在溶液中存在形态改变导致的;HCO_(3)^(-)对As(Ⅲ)氧化的促进作用体现在两方面:(1)与Mn(Ⅱ)形成弱配位,有助于S(IV)和Mn(Ⅱ)结合;(2)促进Mn(Ⅱ)向Mn(Ⅲ)转化,生成SO_(4)^(·-)。淬灭剂实验证明As(Ⅲ)氧化的活性氧化物种是SO_(4)^(·-),丰富了对S(IV)-HCO_(3)^(-)-Mn(Ⅱ)体系的认识,为处理高砷地下水提供了新的解决途径。Advanced oxidation processes based on sulfite[S(IV)]have attracted more and more atten-tion due to their low-cost advantages.In this study,we investigated the oxidation effect and mechanism of As(Ⅲ)in high-arsenic groundwater in the presence of bicarbonate(HCO_(3)^(-))by the Mn(Ⅱ)-activated S(IV)system.The results showed that HCO_(3)^(-) significantly promoted the oxidation of As(Ⅲ)in the S(IV)-Mn(Ⅱ)system.Kinetic experiments showed that increasing concentrations of S(IV)and Mn(Ⅱ)promoted the oxidation of As(Ⅲ),but too high concentrations inhibited the oxidation process.The effect of pH on the oxidation of As(Ⅲ)due to the species changes of S(IV)and Mn(Ⅱ)in the reaction solu-tion.The promotion effect of HCO_(3)^(-) on the oxidation of As(Ⅲ)may due to two aspects:(1)it formed weak coordination with Mn(Ⅱ),which was helpful for the combination of S(IV)and Mn(Ⅱ);(2)it promoted the oxidation of Mn(Ⅱ)to Mn(Ⅲ),which was favorable for the formation of SO_(4)^(·-).Quenching experiments revealed that SO_(4)^(·-) was the primarily reactive oxygen species in the oxidation of As(Ⅲ).This study enhances the understanding of the S(IV)-HCO_(3)^(-)-Mn(Ⅱ)system and provides a new solution for the treatment of high arsenic water.

关 键 词：As(Ⅲ)氧化 亚硫酸盐 碳酸氢盐 

分 类 号：X52[环境科学与工程—环境工程]