三氯化铁除砷和镉的机理  

Mechanism of removing arsenic and cadmium with ferric chloride

作　　者：郭莉[1] 赵燕鹏[1] 杜冬云[1] 

机构地区：[1]中南民族大学化学与材料科学学院,催化材料科学国家民委-教育部共建重点实验室,湖北武汉430074

出　　处：《化工学报》2014年第10期4118-4122,共5页CIESC Journal

基　　金：武汉市重点科技攻关资助项目(201160638171)~~

摘　　要：采用电荷分布多位络合模型模拟（CD-MUSIC）、XPS、FTIR和Zeta电位分析的方法研究了三氯化铁去除As（Ⅴ）、Cd（Ⅱ）的机理。结果表明：在pH 3～7范围内，砷、镉通过竞争铁氧化物表面的有效作用位点而相互抑制；而在pH 7～10范围内，Cd（Ⅱ）主要以Cd（OH）2沉淀的方式得以去除，并通过共沉淀作用促进砷的去除。根据CD-MUSIC 模拟结果，As（Ⅴ）主要形成单齿单核质子化（ FeOAsO3H1.5-、FeOAsO（H2O）20.5-）的表面配合物，结合常数分别为63.04、66.50；而 Cd（Ⅱ）则以 FeOHCd1.5＋形态结合在铁氧化物的表面，结合常数为31.05，其含量随着pH的升高逐渐减少。The mechanism of arsenic and cadmium removal withferric chloride was studied by analysis of residue samples with CD-MUSIC, XPS, FTIR and Zeta potential. There was interference between As and Cd by competing the active site on iron oxide in the range of pH at 3-7. Nevertheless, in the range of pH at 7-10, Cd（Ⅱ）was mainly removed by precipitation as Cd（OH）2, which could increase As removal by co-precipitation. According to the results simulated with CD-MUSIC, As（Ⅴ） was mainly removed by forming monodentate uninuclear surface complexes （FeOAsO3H1.5- and FeOAsO（H2O）20.5-）, with binding constants of 63.04 and 66.50 respectively. Besides, Cd（Ⅱ） was combined on the surface of ferriferrous oxide with the formation of FeOHCd1.5＋ with binding constant of 31.05 and the amount of this complex decreased with rising pH.

关 键 词：三氯化铁 砷 镉去除机理 电荷分布多位络合模型 

分 类 号：X781[环境科学与工程—环境工程]