溴与铜协同还原法脱除污酸中的砷

Arsenic removal from waste acid via synergistic reduction of copper and bromide

针对高酸度的含砷废水处理难度大的问题,通过溴与铜的协同作用将高价态的砷还原为单质来实现脱砷,采用ICP测定、阴离子电极分析、XRF检测对反应前后的溶液滤渣进行了表征;研究了还原反应中各因素对反应的影响。结果表明:反应温度、反应时间、氢离子浓度、铜粉目数及搅拌速率的升高均有利于砷还原反应的发生;增加铜粉及溴化钠用量,有助于反应进行,铜粉与溴化钠过量则引起反应后溶液中铜、溴离子浓度升高。在最优条件下,反应后砷的去除率可达到99.5%以上,溶液中的铜离子为60 mg·L-1以下,通过XRF分析反应后所得的滤渣发现,溶液中的砷均沉淀进入固体。通过溴与铜协同还原的方法,溶液中的高价砷还原为单质,实现了高酸度环境下砷的脱除。

Waste acid is a complex industrial wastewater containing high acidity and arsenic contents and difficult to treat.In this study,a new method was developed to remove arsenic from waste acid based on the synergistic reduction of As(Ⅲ)to elemental As by bromine and copper.The elemental compositions in solution and filtration residue were characterized by ICP measurement,anion electrode analysis and XRF detection,respectively.In addition,the impacts of various factors on the reduction reaction were studied.The results show that the increase of reaction temperature,time,hydrogen ion concentration,the mesh of copper powder and stirring rate facilitated the arsenic reduction reaction.Moreover,increase of copper powder and sodium bromide dosages could conduce to the proceeding of the reduction reaction,while excessive dosage of copper powder and sodium bromide led to an increase in copper and bromide ion concentrations in the solution.Under the optimal conditions,the arsenic removal rate could reach over 99.5%,and the copper ion concentration in the solution was below 60 mg·L-1.XRF analysis on the filtration residue after reduction reaction indicated that the arsenics in the solution precipitated into the solid residual.Through the synergistic reduction by copper and bromide,the high valent arsenic in the solution was reduced to elemental As,then arsenic removal from waste acid containing high acidity could be accomplished.