The use of graphene nanocomposites in the remediation of contaminated soils: Synergies, effectiveness, and liabilities

The use of graphene and its derivatives in environmental science has become a common ground for researchers who develop highly engineered nanocomposites. This is due to graphene's distinguished properties (high electrical and thermal conductivity, great specific surface area, transparency, and high mechanical resistance, among others). Such properties allow the application of graphene as a catalyst and adsorbent for a broad range of water and atmospheric pollutants. However, its employment in soil remediation, which consists nowadays in a knowledge gap, indicates opportunities for investigation. This chapter summarizes the current efforts of scientists and engineers in the synthesis, characterization, and application of graphene nanocomposites for the remediation of contaminated soils. A thorough assessment has been carried out to highlight the main advantages and disadvantages of using graphene and its derivatives in standard and innovative methods of soil treatment. This analysis was performed in terms of treatment efficiency, costs, and technological advances, in comparison to pristine materials. The processes studied focus on: washing followed by adsorption and degradation methods, microwave-assisted extraction, and advanced oxidation. Furthermore, the influence of nanoparticles anchorage (e.g., magnetic nanoparticles, metallic oxides, and nanoclays), and the functionalization and doping of graphene, graphene oxide, and reduced graphene oxide in soil remediation are discussed in depth. Another issue explored is the toxic effects of graphene nanocomposites once they are released in soils and carried to water bodies.