Applications of graphene and its derivatives as an adsorbent for heavy metal and dye removal: a systematic and comprehensive overview

Because of their persistency and toxicity, dyes and heavy metal ions discharged to water bodies have become a worrisome issue. Therefore, to secure the innate beauty of our planet and to conserve our non-renewable natural resources, specifically, water, it is essential to check and/or to minimize heavy metal ion and dye concentrations before discharge. Adsorption is considered as a robust and widely acclaimed water decontamination technology. In material science research, much attention has been focused on graphene, a carbon allotrope with a two-dimensional sheet-like structure possessing unique structural properties that has been utilized in various research areas. Herein, we present recent developments, specifically focusing on the use of graphene and its derivatives as an adsorbent for dye and heavy metal ion removal from aqueous phase. A historical overview, synthesis methodologies, structural characteristics, toxicity issues, and the applications of graphene and its derivatives for dye and heavy metal ion removal along with its adsorption mechanisms are comprehensively discussed. Major challenges in graphene synthesis and future research perspectives for developing alternate synthesis methodologies are also discussed.