Recent advances and prospects on the r-GO incorporated metal oxide semiconductors for enhanced photo-adsorptive abatement of toxic wastewater pollutants

Abstract

Various toxic pollutants such as dyes, pesticides, polycyclic aromatic hydrocarbons (PAHs), substituted phenols, and pharmaceutical waste were discharged into the water bodies and impose serious health hazards to humans as well as to the environment. Therefore, it is crucial to identify sustainable treatment methods for the removal of these harmful pollutants. The reduced graphene oxide (r-GO) based composites have demonstrated improved strength, durability, flexibility, resistance to heat, UV radiation, fire, and electrical and thermal conductivity. Therefore, function as an efficient electron acceptor, enhancing photo induced charge transfer, impeding charge carrier recombination, boosting photocatalytic activity and increasing specific surface area for photocatalytic degradation and adsorption of wastewater pollutants. This review article summarizes the unique properties and green synthesis of r-GO based engineered nanomaterials to lessen toxic organic wastewater pollutants along with their environmental risk assessment for understanding the urgent need for their removal. The previous research and study in this enormous field has been evaluated scientifically and analyzed for finding research gaps. Photocatalysis, an eco-friendly and sustainable method was assessed as an effective method with detailed mechanism by employing solar-activated synthetic nanocomposite of r-GO@metal oxides (CaO, ZnO, Fe2O3, SnO2, TiO2, MgO) with characteristics of low-cost, fast, and efficient for improved adsorption and degradation. This research further assesses degradation routes for various toxic pollutants and active species involved in breakdown into safer metabolites along with the sustainability of r-GO based composites.