Simultaneous treatment of both As(III) and As(V) with Iron-Coated Sand (ICS) and Manganese-Coated Sand (MCS)

From the natural geochemical process and anthropogenic activities such as mining wastes, petroleum refining, and agricultural chemicals, surface and groundwater are widely contaminated with arsenic (Bhumbla and Keefer, 1994). Inorganic arsenic is commonly present as arsenite and arsenate depending on the aquatic redox systems. In anoxic systems such as groundwater, the stable form of arsenic is As(III) which is more toxic and mobile than As(V). Although several methods such as activated alumina, coagulation, membrane or electrolysis have been identified as promising techniques in the treatment of As(V) (Chen et al., 1999), these processes were partly effective to treat As(III), requiring a highly effective and economic technique on the oxidation of As(III) to As(V) as a pre-treatment . In this study, as a promising technique for the treatment of both As(III) and As(V) at the same time in a single reactor, reactor systems containing both manganese-coated sand (MCS) and iron-coated sand (ICS) were used to investigate the oxidation kinetics of As(III) and adsorption of As(V) with variation of the configuration of MCS and ICS in column experiments.