A comparative study on the photo-removal of a few selected priority organic pollutants in aqueous suspension using vanadium-doped-ZnO/MWCNT

Abstract

Highly efficient vanadium doped ZnO nano-rods supported with MWCNTs (V@ZnO/MWCNT) have been fabricated using a convenient sol–gel impregnation method. Techniques such as FTIR, XRD, UV-Vis DRS, TEM, and EDX were used to characterize the synthesized pure, doped, and composite materials. The photocatalytic activity of the V@ZnO/MWCNT photocatalysts was tested by studying the degradation of a few selected priority organic pollutants, such as 5-nitroisophthalic, allopurinol, and chloramine-T, in an aqueous medium under UV light in the presence of atmospheric oxygen. Amongst the different synthesized nanocomposite materials, V@ZnO/MWCNT showed the best photocatalytic activity, which was monitored by measuring the change in absorbance at different time intervals using UV-Vis spectroscopic analysis. The kinetics of degradation were examined under varying conditions, such as type of photocatalyst, reaction pH, catalyst dose, substrate concentration, and potassium bromate as an electron acceptor in addition to molecular oxygen. All the compounds under study degraded more effectively under alkaline pH and potassium bromate. Based on the obtained results, a plausible degradation mechanism has been proposed on the irradiated photocatalysts in an aqueous medium and atmospheric oxygen.