Zinc oxide mediated heterogeneous photocatalytic degradation of organic species under solar radiation

The photocatalytic decomposition of eco-persistent toluene, salicylic acid and 4-chlorophenol with sun light in an oxygenated aqueous suspension has been studied under nanocrystalline hexagonal ZnO photocatalyst. The effect of substrate temperature onto the structural, morphological and photoactive properties has been investigated. The degradation of toluene, salicylic acid and 4-chlorophenol were achieved using a photoelectrochemical reactor module equipped with synthesized ZnO electrodes. Kinetic parameters have been investigated in terms of a first order rate equation. The rate constant (−k) for this heterogeneous photocatalysis was evaluated as a function of the initial concentration of original species. Substantial reduction in concentrations of toluene, salicylic acid and 4-chlorophenol was achieved as analyzed from COD and TOC studies. The mechanism for the degradation of toluene, salicylic acid and 4-chlorophenol could be explained on the basis of Langmuir–Hinshelwood mechanism.

► Approach of degradation of organic species in water is proposed using PEC reactor.
► Flower like ZnO photocatalyst enhances the surface area for reaction.
► Kinetic parameters have been investigated in terms of a first order rate equation.
► Correlation of TOC and COD for extent of mineralization has been investigated.
► Degradation analysis has explained on the basis of Langmuir–Hinshelwood mechanism.