Abstract:

α-FeO(OH) was prepared and characterized. The effects of low relative molecular mass organic acids(LMW) in soils on the adsorption of As(Ⅲ) by α-FeO(OH) were investigated, and the mechanism was elucidated. Single LMW and mixed LMW have inhibitory effect on the adsorption of As(Ⅲ) by α-FeO(OH). The influence order of four LMW on the adsorption of As(Ⅲ) by α-FeO(OH is as follows: oxalic acid (OA)>citric acid (CA)>lactic acid (LA), salicylic acid (SA). The effect of mixed LMW on the adsorption of As(Ⅲ) by α-FeO(OH) is as follows:the OA aggravates the effect of CA on the adsorption of As(Ⅲ) by α-FeO(OH), and addition of SA hardly affects the adsorption of As(Ⅲ) by α-FeO(OH). When the ρ(As(Ⅲ)) is low, the electrostatic attraction of LMW with α-FeO(OH), the formation of complexes with iron ions on the surface of α-FeO(OH), and the formation of precipitates affect the adsorption of As (Ⅲ) by α-FeO(OH). When the ρ(As (Ⅲ)) is high, the LMW affects the diffusion and precipitation of As(Ⅲ). The experimental results provide technical support for the migration, transformation, and pollution control of As(Ⅲ) in soil.

Key words: As(Ⅲ), α-FeO(OH), low molecular mass organic acids, adsorption