title: Effect of arsenate on adsorption of Cd(II) by two variable charge soils.
abstract: The effect of arsenate on Cd(II) adsorption in two variable charge soils and the desorption of Cd(II) pre-adsorbed in the presence of arsenate were studied. The batch type experiments showed, the presence of arsenate led to increase in Cd(II) adsorption and the desorption of pre-adsorbed Cd(II). Further it was observed that the extent of adsorption and desorption of Cd(II) was greatly influenced by the initial concentrations of arsenate and Cd(II), the solution pH, and the nature of the soils. In general the increase in arsenate concentration and pH favored the uptake of Cd(II). Moreover, the arsenate concentration influenced more in Hyper-Rhodic Ferralsol than Rhodic Ferralsol at least for the Cd(II) adsorption/desorption. This may be due to the content of Fe/Al oxides in these soils. The larger the content of Fe/Al oxides, the more the adsorption of arsenate by the soil, hence greater the uptake of Cd(II). It can be assumed that the enhanced Cd(II) adsorption was mainly due to the increase in net negative surface charge of the soil induced by the adsorption of arsenate, because the presence of arsenate led to the decrease in zeta potential of these soil suspensions. The increase of electrostatically adsorbed Cd(II) was responsible for the increase in the desorption of Cd(II) pre-adsorbed in the presence of arsenate.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liang
authors.forename: Renkou
authors.initials: R
authors.lastname: Xu
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Anzhen
authors.initials: A
authors.lastname: Zhao
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Tan
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000737:chemistry*; D019187:Cadmium Compounds / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D012987:Soil / Q000032:analysis / Q000592:standards; D012989:Soil Pollutants / Q000032:analysis*; D012996:Solutions
chemical_list: D001149:Arsenates; D019187:Cadmium Compounds; D012987:Soil; D012989:Soil Pollutants; D012996:Solutions; C025657:arsenic acid