Advances in Graphene-Based Magnetic and Graphene-Based/TiO2 Nanoparticles in the Removal of Heavy Metals and Organic Pollutants from Industrial Wastewater

Abstract

In this review, various graphene-based/TiO2 and graphene-based magnetic nanocomposites which were developed as highly efficient photocatalysts for degrading organic dyes, pharmaceuticals and efficient adsorbent materials for the adsorption of heavy metal ions were reviewed. The nanocomposites revealed the effective adsorptive potential of graphene-based magnetic materials and the efficient photocatalytic ability of graphene-based/TiO2 nanocomposites in decontaminating industrial wastewater containing toxic heavy metals and organic pollutants. The magnetic properties of graphene-based magnetic materials facilitate easy magnetic separation after adsorption of pollutants. The efficient photocatalytic ability of TiO2 semiconductor helps in rapid degradation of organic pollutants while graphene-based materials increase the surface area for adsorption of pollutants. Literature studies show that combinations of synthetic methods have been employed for the generation of various nanocomposite materials such as GO/TiO2, rGO/TiO2, and Fe3O4/GO, that possess photocatalytic activity and magnetic properties for the commercial removal of organic and inorganic pollutants found in water/wastewaters. The photocatalytic performance is connected to the large surface area of graphene derivatives (e.g. GO) that limit electron–hole recombination for TiO2, while the presence of magnetic nanoparticles (e.g. Fe3O4) in heavy metal adsorbent materials facilitates magnetic separation when an external magnetic field is applied.