低相对分子质量有机酸对α-FeO(OH)吸附As(Ⅲ)的影响

制备并表征了α-FeO(OH),探究了4种低相对分子质量有机酸(LMW)对α-FeO(OH)吸附As(Ⅲ)的影响,并阐明了机理。 单一和混合LMW对α-FeO(OH)吸附As(Ⅲ)均有抑制作用,4种LMW的影响大小顺序为:草酸(OA)>柠檬酸(CA)>乳酸(LA)、水杨酸(SA)。 混合LMW的影响为:OA会加剧CA对α-FeO(OH)吸附As(Ⅲ)的影响,而SA几乎不起作用。 当ρ(As(Ⅲ))较低,LMW通过与α-FeO(OH)的静电引力、与α-FeO(OH)表面的铁离子形成配合物、生成沉淀从而影响α-FeO(OH)对As(Ⅲ)的吸附;当ρ(As(Ⅲ))较高,LMW还通过阻碍As(Ⅲ)在α-FeO(OH)上的扩散和沉淀作用产生影响。 实验结果为土壤中As(Ⅲ)的迁移转化、污染治理提供技术支撑。

Effect of Low Relative Molecular Mass Organic Acids on As(Ⅲ) Adsorption by α-FeO(OH)

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.