g-C3N4 Decorated with Hydrogen Peroxide Modified Titania and Bismuth Vanadate for Enhanced Photocatalytic Degradation of Aqueous Methyl Orange Dye

Abstract

The discharge of dye-contaminated wastewater, particularly azo dyes like methyl orange, poses a significant environmental concern, adversely affecting water bodies, ecosystems, and public health. Conventional treatment methods, marred by the production of secondary pollutants and inefficient dye removal, underscore the need for innovative and sustainable alternatives. This study aims to explore a novel approach utilizing ternary composite photocatalyst (15% BiVO4@HMT/g-C3N4) for the degradation of methyl orange (MO) under visible light irradiation. Synthesized catalysts were characterized by analytical techniques like X-ray diffraction, Energy dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy, which confirmed the formation of pure cystalline structures, perfect elemental composition of BiVO4, HMT and 15% BiVO4@HMT/g- C3N4 powders, without incorporation of any impurities. Optical properties of as prepared catalysts were tested with UV-visible diffuse reflectance spectroscopy. Preliminary testing of pristine photocatalysts (BiVO4, hydrogen peroxide-modified titania (HMT), and g-C3N4), as well as binary and ternary composites was carried out. The superior performance of the ternary composite prompted its selection for further experimentation. Optimization studies were conducted to identify the optimal pH, dose, and concentration of the solution for effective methyl orange degradation. The ternary composite is demonstrated to degrade methyl orange up to 79.32%. Additionally, its reusability is evidenced by consistent performance across three cycles, with the third cycle showing approximately 70% degradation efficiency. Degradation reaction rates were assessed by applying First, Pseudo-first and second order kinetics on the photocatalytic degradation data for MO dye. The pronounced efficacy of the ternary composite compared to g-C3N4 alone confirmed its applicability for enhancing the photocatalytic potential under visible light. This study pioneers the investigation of the BiVO4@HMT/g-C3N4 ternary composite's performance and novelty in the context of dye degradation. As a promising solution to the persistent challenge of dye-contaminated wastewater, the ternary composite opens avenues for more efficient, sustainable, and environmentally responsible wastewater treatment practices.