Selenate and Chromate Removal with Titanium Dioxide based Photocatalysts

As selenium and chromium are toxic even at low levels, it is very necessary to remove them from drinking water with proper ways. In this work, titanium dioxide based photocatalysts were mainly investigated in detail for their photoreduction ability towards selenate and chromate in aqueous environment. Firstly, photoreduction ability of layered double hydroxide (LDH) nanosheets with commercial TiO2 particle hybrid materials was investigated towards selenate or chromate. The results showed that commercial LDH/TiO2 (P90) composite, homemade LDH nanosheets/TiO2 (P90) composite and also in situ LDH/TiO2 (P25) composite all did not indicate significant improvement on photoreduction performance towards selenate or chromate. Secondly, TiO2 nanosheets material was synthesized with TiS2 as precursor via hydrothermal treatment. Morphology of TiO2 nanosheets were characterized by SEM, AFM and TEM. Photodegradation of MB (methylene blue) with TiO2 nanosheets was performed. In the future, first approach is to synthesize visible-light driven LDH photocatalyst NiFe-LDH nanosheets with TiO2 nanosheets hybrid material for selenate removal. Second approach is to use anion intercalation/insertion via electrochemical process to remove anions in drinking water.