Research progress of the application of graphene-based materials in the treatment of water pollutants

Graphene-based nanomaterials have attracted increasing attention in different areas, such as material science, chemical engineering and environmental science. In recent years, it and its derivatives (e.g. graphene oxide, reduced graphene oxide) have been considered promising functional materials in water pollution control because of their many unique properties. Recent intense research on the development of graphene-based composite materials has expanded their application to water treatment. Progress in the use of graphene, graphene oxide and graphene-based composite materials in water pollutant treatment is reviewed, including their use as adsorbents, photocatalysts, and the oxidant and oxidant (e.g. H2O2, peroxymonosulfate) activators in electrocatalysis. Water pollutants are heavy metal ions, dyestuffs, some inorganic nutrients and the emerging environmental pollutants. Not only are the mechanisms of the use of graphene and its derivatives in different treatment processes considered, but the effects of important factors on the removal efficiency of pollutants are analyzed, such as environmental factors (e.g. pH, pollutant concentration), the properties of the materials (e.g. particle size, surface charge) and the concentration and morphology of the material. Current problems of using graphene-based composite materials in water treatment are summarized and future research directions are proposed.