Adsorption and Stability of Arsenic(III) at the Clay Mineral−Water Interface

• Published in: Environmental science & technology Vol. 31; no. 7; pp. 2005 - 2011
• Main Authors: Manning, Bruce A, Goldberg, Sabine
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-07-1997
• Subjects: Adsorption; AGUA; Applied sciences; ARSENIC; ARSENICO; Biological and physicochemical properties of pollutants. Interaction in the soil; Chemical reactions; Chemistry; CLAY MINERALS; EAU; Exact sciences and technology; Freshwater; MINERAL ARGILEUX; MINERALES DE ARCILLA; Pollution; Soil and sediments pollution; WATER; Clay; Adsorption; Pollutant behavior; Chemical stability; Mobility; Arsenic III; Soil interaction; Oxidation; Soil pollution; Modeling; Interface
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9608104

Adsorption and oxidation reactions of arsenite (As(III)) at the mineral−water interface are two important factors affecting the fate and transport of arsenic in the environ ment. Numerous studies have concluded that As(III) is more soluble and mobile than arsenate (As(V)) in soils, though very little experimental work has demonstrated the differences in reactivity and stability of As(III) and As(V) at the mineral−water interface. In this investigation, As(III) adsorption on kaolinite, illite, montmorillonite, and amorphous aluminum hydroxide (am-Al(OH)3) was studied as a function of pH and ionic strength and was compared with As(V) adsorption. High-performance liquid chromatog raphy−hydride generation atomic absorption spectrophotometry (HPLC−HGAAS) was employed for direct determination of As(III) and As(V). In addition, surface complexation modeling was used to describe As(III) and As(V) adsorption on the four minerals. It was revealed that alkaline solutions (pH > 9) without mineral solids caused homogeneous oxidation of As(III) to As(V). In addition, recovery of adsorbed As from As(III)-treated clay mineral solids showed that oxidation of As(III) to As(V) was enhanced by heterogeneous oxidation on kaolinite and illite surfaces.