Abstract: The mechanism of removing As (Ⅲ)with ferric chloride was studied by analysis of residue samples by XPS, SEM, TEM and IR in this paper.The results showed that As(Ⅲ)was removed mainly by adsorption and coprecipitation.It was indicated by XPS analysis that redox reaction occurred when ferric choride was used.It was also observed from the SEM and TEM imagines that, with rising of pH value, residues changed from particles to irregular floculents, size of particle gradually increased, and there were adsorbed species at surface of these particles.A conclusion could be obtained from IR results that there was no ferric arsenate in the residues.

Key words: ferric chloride, mechanism of arsenic removal, ferric arsenate, arsenic

摘要： 采用XPS、SEM、TEM和红外分析的方法研究了三氯化铁除砷(Ⅲ)的机理。结果表明，三氯化铁是通过吸附共沉淀的方式去除水中的砷(Ⅲ)。XPS的数据表明在氯化铁处理含砷(Ⅲ)废水时有氧化还原反应发生；从SEM和TEM图可以看出随着溶液pH的升高，沉淀物从颗粒状态逐渐变为不规则的絮凝状态，颗粒粒径逐渐增大，表面有吸附物质存在；而从沉淀物的红外光谱图可以推断无砷酸铁生成。

关键词: 三氯化铁, 除砷机理, 砷酸铁, 砷