Inorganic Analogues of Graphene and Their Nanocomposites for Wastewater Treatment

Abstract

Water scarcity has been a grave concern because of increasing urbanization and industrialization activities, unrestrained exploration of natural sources, and depletion of water table. Water pollution causes severe health hazards and jeopardizes biodiversity and the aquatic ecosystem. Therefore, wastewater treatment technologies for providing clean water through sustainable and economic approaches are gaining increasing interest. Adsorption and photocatalytic degradation of organic pollutants by a wide range of activated carbons and nanostructured materials have been addressed for their adsorptive separation and mineralization. The invention of graphene in 2004 has propelled immense interest in different types of two-dimensional (2D) nanostructured materials for a diversified range of energy and environmental applications. The 2D nanostructured analogues of graphene, viz. MoS2, WS2, h-BN, g-C3N4, MXenes, and their composites of high accessible surface area, controlled surface functionalities, and tunable band-gap have shown excellent performance for wastewater treatment. The chapter covers a comprehensive overview of various types of pollutants in water and recent developments on their adsorptive removal and photocatalytic mineralization/conversion by nanostructured MoS2, WS2, h-BN, g-C3N4, MXenes, and their nanocomposites, heterostructures, and hybrids. The structural, surface, textural, and chemical properties of 2D nanomaterials are reviewed to highlight their roles in the adsorptive removal and photocatalytic degradation of organic pollutants. The chapter also covers futuristic opportunities, environmental sustainability, and technological challenges in preparing and applying inorganic analogues of graphene for wastewater treatment.