Photocatalytic Degradation of Nitrobenzene with Keggin-type Fe(III)-Substituted Heteropolyanion PW11O39Fe(III)(H2O)4-

A novel system using the Keggin-type PW11O39Fe(III)(H2O)(4-) [PW11Fe(III)(H2O)] to substitute Fe3+ in conventional photo-Fenton as a photo-catalyst was developed. This novel system was applied to degrade the aqueous biorefractory organic pollutant nitrobenzene (NB). The homogeneous photocatalytic degradation of NB by PW11Fe(III)(H2O) was studied in detail under an artificial UV irradiation and the existence of hydrogen peroxide (H2O2), in which the effects of initial NB concentration, pH, H2O2 and PW11Fe(III)(H2O) concentration on the photocatalytic degradation rate of NB were examined. The experimental results show that ca. 93% NB degradation ratio was obtained in less than 120 min in a pH 6.86 mixed phosphate solution containing 1.0 mmol.L-1 NB+1.0 mmol.L-1 PW11Fe(III)(H2O)+5.0 mmol.L-1 H2O2 under irradiation with a 300 W Hg lamp, and a total organic carbon (TOC) removal of ca. 31% was achieved, indicating an excellent efficiency and advantage in photo-catalytic degradation of NB by this novel system.