Fabrication of zinc oxide nanorod incorporated carboxylic graphene/polyaniline composite and its photocatalytic activity for the effective degradation of diuron from aqueous solutions

A novel zinc oxide nanorod incorporated carboxylic graphene/polyaniline (ZnR@CGR/PANI) composite was synthesized for the effective removal and subsequent photodegradation of the pesticide diuron (DU) from aqueous solutions. The photocatalyst was characterized by FTIR, XRD, SEM, TEM, Surface Area Analyzer, Raman spectroscopy AFM, DRS, PL and Cyclic voltammetry. The photocatalytic performance of ZnR@CGR/PANI composite was evaluated by the degradation of DU under visible light irradiation. The band gap of the photocatalyst was found to be 2.77 eV. The maximum adsorption occurs at pH 4.0. The adsorption kinetic and isotherm data were described using pseudo-second-order kinetic model and Sips isotherm model, respectively. Adsorption capacity increases with increase of temperature indicates the endothermic nature of adsorption. The maximum adsorption capacity was found to be 13.40 mg/g. The photocatalytic degradation of DU was found to follow first-order kinetics and optimum pH for degradation was found to be 3.0. The regeneration of the adsorbent-cum-photocatalyst was also examined upto five cycles that confirmed the relative stability of the photocatalyst.