A visible-light active g-C3N4/Ce–ZnO/Ti nanocomposite for efficient photoelectrocatalytic pharmaceutical degradation: Modelling with artificial neural network

Abstract

Herein, a visible-light active g-C3N4/Ce–ZnO/Ti nanocomposite was successfully prepared by the immobilization of g-C3N4 and Ce–ZnO nanoparticles on a titanium grid sheet through the electrophoretic deposition method. The prepared nanocomposite was characterized by SEM, EDX, XRD, PL, photocurrent and DRS analyses. The photoelectrocatalytic activity of the catalyst was evaluated for the degradation of cefixime as a pharmaceutical pollutant. After five cycles of use, almost no weight loss of the immobilized particles was observed. The effect of operating variables i.e. catalyst dosage, solution pH, bias potential, electrolyte concentration, pollutant initial concentration and light power was investigated on the removal efficiency of the cefixime. It was observed that almost 80 % degradation was achieved at the conditions of pH 7, bias potential 0.9 V, Na2SO4 concentration 35 mM, initial cefixime concentration 10 mg/L and light power 72 W using two g-C3N4/Ce-ZnO/Ti under the visible light irradiation for 180 min. Moreover, the proposed model based on the artificial neural network could predict the photoelectrocatalytic degradation process. Sorption, electrosorption and photocatalytic processes respectively with cefixime removal efficiency of 6.7 %, 16 % and 28.7 % could not compete with the photoelectrocatalytic process. Finally, the result of TOC analysis (96 % reduction after 330 min) confirmed that g-C3N4/Ce–ZnO/Ti through the visible light photoelectrocatalytic process could effectively mineralize cefixime from aqueous solution. In addition, GC–MS analysis was employed to identify cefixime degradation products.