酸性废水中As(Ⅲ)、Cu(Ⅱ)与铁粉的反应行为

在Fe-As(Ⅲ)-Cu(Ⅱ)-H₂O体系中, 研究了酸性废水中As(Ⅲ)、Cu(Ⅱ)与金属铁粉的反应行为, 考察了反应过程中As在气、液、固三相中的分配比。结果表明, As(Ⅲ)和Cu(Ⅱ)离子被Fe还原为单质As和Cu后, As、Cu进一步结合成Cu₅As₂等金属间化合物, 从而促进As(Ⅲ)沉淀反应的发生, 且无AsH3生成。在反应时间40min、铁粉过量系数1.2、溶液初始pH=0.0、温度40 ℃、Cu/As摩尔比1.0条件下, As在气、液、固三相中的分配比分别为0、20.7%和79.3%, 沉砷率为79.3%。

Reaction Behavior of As(Ⅲ) and Cu(Ⅱ) in Acidic Effluent with Iron Powder

The reaction behavior of As(Ⅲ) and Cu(Ⅱ) in acidic effluent with metallic iron powder was investigated in the Fe-As(Ⅲ)-Cu(Ⅱ)-H₂O system. The distribution ratios of As in gas, liquid and solid phases during the reaction were investigated. The results showed that As(Ⅲ) and Cu(Ⅱ) ions were firstly reduced by Fe to elemental As and Cu, which were then combined into intermetallic compounds, such as Cu₅As₂, thus promoting the precipitation of As(Ⅲ), with no AsH3 generated. It is shown that after 40-min reaction at a temperature of 40 ℃, with an excess coefficient of iron powder at 1.2, the initial pH of the solution at 0.0 and a molar ratio of Cu/As of 1.0, the distribution ratios of As in gas, liquid and solid phases are 0, 20.7% and 79.3%, respectively, and the precipitation rate of As is 79.3%.