Interaction of cadmium with phosphate on goethite

被引:78
作者
Venema, P [1 ]
Hiemstra, T [1 ]
vanRiemsdijk, WH [1 ]
机构
[1] WAGENINGEN UNIV AGR,DEPT SOIL SCI & PLANT NUTR,NL-6700 EC WAGENINGEN,NETHERLANDS
关键词
goethite; iron; oxohydroxide; oxide; adsorption; interaction; modeling; cadmium; phosphate;
D O I
10.1006/jcis.1997.4988
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Interactions between different ions are of importance in understanding chemical processes in natural systems, In this study simultaneous adsorption of phosphate and cadmium on goethite is studied in detail, The charge distribution (CD)-multisite complexation (MUSIC) model has been successful in describing extended data sets of cadmium adsorption and phosphate adsorption on goethite, in this study, the parameters of this model for these two data sets were combined to describe a new data set of simultaneous adsorption of cadmium and phosphate on goethite, Attention is focused on the surface speciation of cadmium. With the extra information that can be obtained from the interaction experiments, the cadmium adsorption model is refined. For a perfect description of the data, the singly coordinated surface groups at the 110 face of goethite were assumed to form both monodentate and bidentate surface species with cadmium. The CD-MUSIC model is able to describe data sets of both simultaneous and single adsorption of cadmium and phosphate with the same parameters. The model calculations confirmed the idea that only singly coordinated surface groups are reactive for specific ion binding. (C) 1997 Academic Press.
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页码:94 / 103
页数:10
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