Accelerated Decoloration of Organic Dyes from Wastewater Using Ternary Metal/g-C3N4/ZnO Nanocomposites: An Investigation of Impact of g-C3N4 Concentration and Ni and Mn Doping

Abstract

Wastewater from many sectors that contains hazardous organic pollutants exacerbates environmental contamination. Consequently, outstanding photocatalytic substances that can successfully degrade hazardous substances are needed to provide pollution-free water. From this perspective, zinc oxide/g-C3N4-based composites are desirable due to their low cost, strong reactivity, and environmental friendliness. So, in the current investigation, sequences of Mn/g-C3N4/ZnO (Mn/GZ) and Ni/g-C3N4/ZnO (Ni/GZ) nanocomposites (NCs) containing different concentrations (wt.%) of g-C3N4 were made via the co-precipitation process. The chemical makeup and morphological characteristics of the produced composites were ascertained via the techniques of transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), photoluminescence (PL), and UV spectrophotometry. Methyl orange (MO) and Eriochrome Black T (EBT) dyes were used as target pollutants to assess the composite materials’ photocatalytic effectiveness. Compared to g-C3N4/ZnO and g-C3N4, the produced Mn/GZ and Ni/GZ NCs displayed better photocatalytic activity. The improved photocatalytic efficiency of the Ni/GZ and Mn/GZ NCs might be credited to synergistic interactions at the g-C3N4 and ZnO interface that result in a more efficient separation and conduction of photo-induced charges. Furthermore, the Ni/Mn atoms act as the facilitators to improve electron–hole pair separation and conduction in NCs. The nanocomposites were found to be incredibly stable, with consistently high dye decoloration efficiency over five catalytic cycles. Hence, Ni/GZ and Mn/GZ could potentially be very effective and adaptable photocatalysts for the photocatalytic decoloration of wastewater pollutants.