Application of photocatalysis and ferrate (VI) oxidation in removal of organic compound for water purification

Abstract

A semi-batch swirl-flow monolithic-type photocatalytic reactor is used to distinguish a??kinetica?? regime from a??optimal workinga?? regime using organic (surfactants and isopropanol) compounds in aqueous Degussa P25 TiO2 suspension. The intrinsic (pure) kinetic rate constants were determined as a function of light intensity experimentally after correcting for mass transfer limitations. Other parameters such as initial pH, initial substrate concentration and dissolved oxygen, which affect the photodegradation and photomineralization rates, were also examined. Attempt to study isopropanol is aimed to provide a basis for organic removal in DI water reclaim for semiconductor industry. Acetone, an oxidized product of the photodegradation was identified. Optimal working parameters were proposed from both mono-parametric and bi-parametic (catalyst loading and light intensity) study. Besides, oxidation of a cationic surfactant, CPC by ferrate (FeO42-) was investigated. More than 95% removal of total organic carbon can be achieved under appropriate conditions. The stepwise additions of ferrate into CPC solution revealed steps involved in the oxidation reaction.