This study investigates the reactivity and removal kinetics of arsenite on mixed mineral systems from aqueous solution related to contaminated waters. The sorbents used were kaolinite, montmorillonite, goethite, and their mixtures. The effects of, proton coefficient, and sorption kinetics were studied at room temperature (23 ± 2°C). Reactivity studies demonstrate reduction in proton coefficient and the acidity of reactive sites by mixed mineral systems, thus impeding arsenite removal by proton exchange. Kinetic studies demonstrate three phase reactions attributed to outer sphere complexation, inner sphere complexation and intra-particle diffusion. Mineral mixing reduced the mass transfer rate of arsenite for kaolinite/montmorillonite in all reaction phases. The behaviors of the mixed mineral systems in arsenite sorption suggest that different reactive sites were involved at the onset of sorption, with reactions and sorption ending in intra particle diffusion over time. Mineral mixing increased % sorption when compared with the single mineral systems. % sorption was a function of the surface area of the mineral sorbent.
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