Redox behavior and chemical species of arsenic in acidic aqueous system  

砷在酸性溶液体系中的氧化还原行为和化学形态（英文）

作　　者：Jin-qin YANG Li-yuan CHAI Qing-zhu LI Yu-de SHU 杨锦琴;柴立元;李青竹;舒余德(中南大学冶金与环境学院,长沙410083;中南大学国家重金属污染防治工程技术研究中心,长沙410083)

机构地区：[1]School of Metallurgy and Environment, Central South University, Changsha 410083, China [2]National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution,Central South University, Changsha 410083, China

出　　处：《Transactions of Nonferrous Metals Society of China》2017年第9期2063-2072,共10页中国有色金属学报（英文版）

基　　金：Projects (51304251,51374237) supported by the National Natural Science Foundation of China;Project (201509050) supported by Special Program on Environmental Protection for Public Welfare,China

摘　　要：Arsenic(As)removal from smelting acidic wastewater is an urgent task.The most common method is oxidation of trivalent As(III)to pentavalent As(V)subsequently precipitated by ferric(Fe(III))salts.Foundations of redox behavior and chemical species are of great importance for understanding As removal.In this work,cyclic voltammetry(CV)and UV?Vis spectroscopy were used for laboratory observation;meanwhile HSC and MINTEQ software were employed for theoretical analyses.It is found that As(III)oxidation,a multiple electron transfer reaction,is diffusion-controlled.The oxidation over-potential is very high(about0.9V)in sulfuric acid solutions(pH1.0).In addition,Fe(III)?As(V)complexes are evidenced by UV?Vis spectra and chemical species analyses in series of Fe(III)?As(V)?H2SO4?H2O solutions.Therefore,the Fe(III)and As(V)species distribution against pH values are determined and a newφ?pH diagram with inclusion of Fe?As complexes is consequently compiled based on thermodynamic data predicted by other researchers.冶炼酸性废水中砷的去除是一项十分紧迫的工作。目前最常用的方法是先将三价砷氧化为五价砷,然后再以铁盐进行沉淀去除。砷的氧化还原行为及化学形态基础研究对于砷的去除意义重大。采用循环伏安法和紫外可见分光光度法开展实验室研究,采用HSC和MINTEQ软件进行理论分析。研究发现三价砷的氧化是一个多电子转移反应,受扩散控制;在pH 1.0的硫酸溶液中,三价砷的氧化过电位非常高(约0.9 V)。另外,针对Fe(Ⅲ)-As(V)-H_2SO_4-H_2O系列溶液的紫外-可见光谱以及物质形态分析均表明Fe(Ⅲ)-As(V)配合物的存在。因此,基于其他研究者预测的热力学数据,绘制Fe(Ⅲ)、As(V)的物质形态随pH的分布规律图和包含Fe-As配合物的新型电位-pH图。

关 键 词：ARSENIC ferric-arsenic complexes φ-pH diagram chemical species acidic wastewater 

分 类 号：O613.63[理学—无机化学]