Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/15635
Title: Adsorption of dimethylarsinate (DMA) monomethylarsonate (MMA), and arsenate on Goethite (alpha-FeOOH)
Authors: ZHANG JUNSHE
Keywords: Goethite Arsenate MMA DMA Adsorption Heterogeneity
Issue Date: 10-Oct-2006
Source: ZHANG JUNSHE (2006-10-10). Adsorption of dimethylarsinate (DMA) monomethylarsonate (MMA), and arsenate on Goethite (alpha-FeOOH). ScholarBank@NUS Repository.
Abstract: This thesis investigates adsorption mechanisms of arsenate, monomethylarsonate (MMA), and dimethylarsinate (DMA) on goethite. Arsenate and MMA adsorb in a similar manner, presumably as bidentate complexes at low surface coverages. Monodentate complexes become more important as surface coverages increase. DMA is much more weakly adsorbed, presumably as monodentate complexes. Adsorbed DMA can be completely displaced by phosphate, but only a portion of adsorbed MMA or arsenate can exchange with phosphate. The competitive adsorption results indicate that there are two types of reactive sites for MMA or arsenate; however only one type exists for DMA. The complex adsorption and desorption kinetics indicate a heterogeneous surface. DMA and MMA adsorption had no effect on the zeta potential of the goethite, consistent with the singly coordinated hydroxyls being the arsenic sorption sites, but other surface oxygens controlling surface charge.
URI: http://scholarbank.nus.edu.sg/handle/10635/15635
Appears in Collections:Ph.D Theses (Open)

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