In order to investigate the effect of ferrous salt oxidation flocculation on arsenic removal, using FeSO4·7H2O as oxidation flocculant, the effects of different concentrations of Fe (Ⅱ) and pH on arsenic removal were explored. The Fe(oxy) hydroxides under different pH were analyzed by TEM. The results showed that with the increasing of Fe(Ⅱ) content, the removal percentage of As(Ⅴ) increased, while the removal percentage of As(Ⅲ) decreased first and then increased. With the increasing of pH, the removal percentage of As(Ⅴ) and As(Ⅲ) both increased first and then decreased. On the conditions of As/Fe molar ratio of 0.5 and initial concentration of 0.5 mmol/L As (Ⅴ) and As(Ⅲ), the As(Ⅴ) was adsorbed and coprecipitated to form ferrihydrite and ferric arsenate formed at pH 9.0, and the removal percentage of As(Ⅴ) was 63.7%after 0.5 h;the As(Ⅲ) was coprecipitated and adsorbed to form ferric arsenate at pH 11.0, and the removal percentage of As(Ⅲ) was 75.7%after 0.5 h.%为探讨利用Fe(Ⅱ)盐氧化絮凝对As(Ⅲ)和As(Ⅴ)的去除效果,采用FeSO4·7H2O作为氧化絮凝剂,探究不同初始Fe(Ⅱ)浓度和pH对As(Ⅲ)和As(Ⅴ)去除效果的影响,并通过TEM分析不同pH下最终生成的铁(羟基)氧化物.结果表明:随着Fe(Ⅱ)加入量的提高,As(Ⅴ)的去除率升高,As(Ⅲ)的去除率先降低后升高;随着溶液初始pH的升高,As(Ⅴ)和As(Ⅲ)的去除率均先升高后降低;在初始As/Fe摩尔比为0.5、As(Ⅴ)和As(Ⅲ)的初始浓度均为0.5 mmol/L条件下,在pH为9.0时,溶液中同时形成水铁矿和砷酸铁,通过吸附和共沉淀作用去除As(Ⅴ),反应0.5 h后去除率为63.7%;在pH为11.0时,溶液中形成砷酸铁,通过共沉淀和吸附作用去除As(Ⅲ),反应0.5 h后去除率为75.7%.
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