As(V) wastewater treatment using Fe(III) - Supported resins

Contaminated water by arsenic is one of the serious problems in the world. Especially in South Asian area, there is a danger of exposure to arsenic by drinking contaminated groundwater. Ion exchange resins packed into columns have been widely used in wastewater treatment. Furthermore, Fe(III) salts have been widely known as an economical reagent for As(V) removal. Therefore, the aim of this study was to investigate As(V) removal mechanism using Fe(III)-supported resins. First, As(V) removal experiment with the batch method was conducted. The chemical states of Fe(III) and As(V) in ion exchange resins were evaluated by Electron probe micro analyzer (EPMA) and X-ray absorption fine structure (XAFS) spectroscopy. These results suggested that Fe(III) diffusion inside the resin was the rate-determining step, requiring prolonged reaction time for As(V) removal. These solid analysis results also suggested that As(V) was removed by the combination of surface precipitation of ferric arsenate and surface complexation to ferrihydrite. Furthermore, Column test for As(V) removal experiments were conducted using the column packed with Fe(III)-supported resins. It was confirmed that the column packed with Fe(III)-supported resins achieved both As(V) uptake and solid-liquid separation at once.