Water pollution remediation: Synthesis and characterization of poly(o-methylaniline)/ZnO/rGO composite for photocatalytic degradation of dyes

Water pollution is growing at an alarming rate, particularly due to the colored wastewater released by the various industries into aquifers and fresh water sources, and in some extreme cases, they have reached the water table. Faisalabad, a city in Pakistan where there is an industrial cluster of textiles dyeing and manufacturers, water table has become undrinkable. The presence of hazardous dyes and chemicals imposes serious health issues on humans, animals, and plants. The treatment of such toxic dye effluents is crucial and could be done by efficient degradation methods such as photocatalysis. The current study presents synthesis of poly(o-methylaniline)/zinc oxide/reduced graphene oxide nanocomposite (POMA/ZnO/rGO NC) using a chemical oxidative polymerization process and explores its properties as a photocatalyst by demonstrating degradation of three dyes. The composite was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence emission spectroscopy (PL), Brunauer Emmett-Teller analysis (BET), and UV-visible spectroscopy (UV-visible). Further, the photocatalytic activity of POMA/ZnO/rGO NC was evaluated and compared by degrading the direct yellow 12 (DY 12), congo red (CR), and malachite green (MG) dyes in aqueous media under UV irradiation. The results indicated that after 110 min, POMA/ZnO/rGO composite degraded the dyes by 92% (DY 12), 86.1% (CR), and 82.1% (MG), respectively. Moreover, kinetic studies of the photocatalyst were also performed along with reusability test, total organic carbon, chemical oxygen demand, and degradation mechanism.