Polyaniline-supported g-C3N4/ZnO/Ag2CrO4 composite for photodegradation of methylene blue under visible light irradiation

Abstract

Organic dyes are a major source of environmental pollution from different industries. To remove these recalcitrant, a novel ternary g-C₃N₄/ZnO/Ag₂CrO₄ and its polyaniline-supported (PANI) composites were synthesized using an “in situ” oxidative polymerization approach. XRD, SEM, UV–Vis DRS, and PL techniques were utilized to characterize the as-prepared composites. The photocatalytic efficiency was evaluated using a model organic pollutant, methylene blue (MB), and samples of the effluent of the textile industry. The as-synthesized ternary g-C₃N₄/ZnO/Ag₂CrO₄ (ZT3= 87.87 %) composite showed better photocatalytic performance than the single (5 %) and binaries (15–25 %) counterparts for MB degradation. The influence of various experimental settings on the photodegradation of MB dye was examined and these were an initial dye amount of 10 ppm, photocatalyst load of 0.15 g/L, and pH 10. Under optimized conditions, PANI-supported g-C₃N₄/ZnO/Ag₂CrO₄ composite (PAST) demonstrated substantial degradation efficiency (97.5 %). The reusability study of the spent catalyst revealed a reduced efficiency from 97.5 to 78.5 % photodegradation of MB after four successive cycles, demonstrating the photocatalyst's stability and efficiency. According to the study on the effect of scavengers, h⁺ plays a significant part in the discoloration of MB. The PAST photocatalyst outperformed the MB discoloration (97.5 %) and adequate degradation for real textile effluent samples (77.7 %) collected from Hawassa textile industries. The photodegradation efficiency result of this study demonstrated that PANI-supported g-C₃N₄/ZnO/Ag₂CrO₄ might serve as an advantageous photocatalyst for the efficient removal of MB and other dyes under visible light irradiation at the optimum conditions. The total estimated cost analysis of synthesis and photocatalytic degradation using Polyaniline-supported g-C₃N₄/ZnO/Ag₂CrO₄ composite found that it was quite affordable, costing around $5 per 1,000 L of wastewater treatment.