Fe Doped TiO2 Prepared by Microwave-Assisted Hydrothermal Process for Removal of As(III) and As(V) from Water

Abstract

Elevated concentrations of arsenic in groundwater, which is used as a source for drinking water, is a worldwide problem. Use of TiO2 and iron doped TiO2 synthesized by a microwave-assisted hydrothermal method for As(III) and As(V) removal were examined. Synthesized sorbents were characterized with XRD and nitrogen physisorption. Synthesized sorbents have predominantly anatase structure, and no peaks for iron could be observed. Doping of iron increases the surface area of synthesized sorbents. Sorption experiments show that increase of iron in sorbents increases the sorption capacity for As(III) and As(V). Increase of pH from 3 to 11 has no influence on As(III) sorption but decreases the sorption of As(V). Batch isotherm studies were performed to determine the binding capacities of As(III) and As(V). As(III) followed the Freundlich isotherm model, while for As(V) a better fit was with the Langmuir isotherm. The results of competition of SO42- and PO43- anions on adsorption of As(III) indicated that both anions reduced substantially the efficiency of adsorption on both adsorbents while for As(V) only the presence of PO43- anion interfered with adsorption. Testing 10Fe/TiO2 sorbent with arsenic contaminated natural water showed that this material could be used for removal of arsenic to the level recommended by WHO without pretreatment.