科研之友
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摘要
Aluminium and iron oxy(hydr)oxides in nature are often partially substituted by other elements and strongly influence the mobility of arsenic in the environment. Because goethite is commonly found in soils, and the oxide is easily substituted, in the present work, the adsorption of As-V onto several Al-substituted goethites was explored in order to determine how substitution affects the adsorption process. Three samples with increasing Al content (GAl(0), GAl(3.78) and GAl(7.61)) were prepared and fully characterised. The variations in As V adsorption under different conditions, as well as the variations of the particle surface charge, were analysed. The results showed that the removal capacity of Al-goethites is determined by the Al content. The adsorption maxima per gram followed the trend GAl(0). GAl(3.78). GAl(7.61), indicating that Al incorporation decreases As-V sorption. Adsorption per surface area decreased in the order GAl(3.78). GAl(0). GAl(7.61), implying that a small incorporation of Al enhances the adsorption properties of the surface. The stoichiometry of the probable surface complexes formed with the contaminant at different pH values is proposed, by analysis of all the experimental results obtained before and after As-V adsorption. These surface complexes were used to fit the experimental data with good agreement, and the formation and acidity constants were also estimated.
- 出版日期2016
