Treatment of Automotive Paint Wastewater: Photocatalytic degradation of methylene blue using semi-conductive ZrO2

Abstract

Addressing water pollution, particularly in the automotive industry's painting processes, is vital due to its significant environmental impact, and the use of photocatalysis, an environmentally friendly and energy-efficient advanced oxidation method, holds promise for removing non-biodegradable organic dyes from wastewater. In this study, the use of semiconductor ZrO2 nanoparticles in the photocatalytic degradation of pollutants in wastewater under UV light was investigated. Zeta potential, Brunauer–Emmett–Teller (BET) surface area and UV-Vis absorption spectroscopy analyses were performed on the ZrO2 nanoparticle synthesized under optimized experimental conditions. ZrO2 nanoparticles synthesized under the optimized experimental conditions exhibited a high specific surface area (51.793 m2/g). ZrO2 nanoparticles had strong absorption in the visible light region, and the energy band gap was estimated to be approximately 3.062 eV. The photocatalytic activity was evaluated by the degradation of methylene blue under UV light (366 nm). The effects of parameters such as the amount of catalyst, concentration and pH of the dye solution, the wavelength of the UV light source used (366 and 254 nm) and the type of test environment on the removal efficiency of methylene blue were investigated. ZrO2 nanoparticles showed a high degradation efficiency of 91% in a strong alkaline environment, which may be the result of the facilitated formation of –OH radicals due to the increased concentration of hydroxyl ions.