Visible light-driven photocatalytic degradation and mineralization of neutral red dye in a slurry photoreacter

Abstract

Hydroxyl radicals (OH^.) induced photocatalytic degradation of neutral red was investigated in a batch slurry reactor, in the presence of visible light illuminated ZnO. The effects of process parameters such as catalyst loading, initial substrate concentration, Fenton reagent, temperature, solar light and oxidant, and anion concentration were investigated. In the presence of visible light, ZnO/Fenton process was found to be most efficient for the decolorization of dye. Both artificial visible radiation and solar light degraded dye efficiently in the presence of ZnO. The destruction of chromophoric part and aromatic skelton of dye were ascertained by the disappearance of absorption bands in UV/Vis spectra of dye with respect to irradiation time. Complete COD reduction was observed in 8 h of irradiation time. CO₂ and NO₃^- ionswere identified as final mineralization products.