Graphene-based materials for water and wastewater treatment: A comprehensive review of advances in synthesis, emerging applications, and future directions
Ahmed M.E. Khalil, Tanveer A. Tabish, B.D. Joshi, Mohamed Egiza, Fayyaz A. Memon, Shaowei Zhang
Abstract
Graphene-based materials (GBMs) have emerged as promising candidates for water and wastewater treatment owing to their large surface area, high electron mobility, tunable surface chemistry, and exceptional mechanical strength. This review provides a comprehensive examination of key advances in the synthesis, performance optimisation, environmental implications, and future integration strategies of GBMs for pollutant removal. Emphasis is placed on the removal of emerging contaminants including pharmaceuticals, personal care products, heavy metals, dyes, and pathogenic microorganisms using material descriptors together with kinetic and thermodynamic analyses. Enhanced adsorption capacities, in some cases exceeding 30% over conventional materials, are achieved via functionalisation and the development of three-dimensional graphene architectures, graphene oxide nanoribbons, and activated graphene. Green synthesis approaches using plant- and fruit-based reducing agents are highlighted as environmentally benign alternatives to conventional chemical methods, reducing toxic by-products and energy demand. Despite these advances, challenges remain regarding scalable, cost-effective, and reproducible synthesis of graphene with controlled porosity and surface functionality, alongside assessment of long-term environmental fate, ecotoxicity, and regeneration potential. The review further explores integration strategies with existing treatment technologies such as membrane filtration, electrochemical processes, and bioreactors to improve treatment efficiency and operational sustainability. Future research directions are proposed to support the transition from laboratory-scale innovation to full-scale deployment, emphasising interdisciplinary collaboration for the development of safe, efficient, and economically viable water purification systems. Overall, this review provides an up-to-date, integrated synthesis across adsorption, catalytic oxidation and membrane separations, linking processing routes to material descriptors and performance metrics.