Graphene is an interesting two-dimensional carbon sheet possessing
single-layered atom thickness that confers unique physical
and chemical properties. The pristine graphene sheets have
some limited applications in water purification, but the modification
of graphene into the graphene composite by the incorporation
of some functional groups or nanoparticles on the
surface extensively increases its environmental applications. Recently,
graphene nanocomposites have found to show very
promising applications in all types of water purification. The
present review highlights the recent developments in the applications
of graphene and graphene-based composites as adsorbent,
catalyst, photocatalyst, electrocatalyst, photoelectrocatalyst,
and disinfection and desalination agent in
comprehensive water purification systems. We primarily focus
on the environmental engineering applications of graphene
nanocomposites as sorbent materials for the elimination of toxic
inorganic (cationic and anionic), organic, and mixed/multiple
pollutants, and as catalysts for the degradation of toxic organic
contaminants using catalytic oxidation, photocatalytic oxidation,
electrocatalytic oxidation, and photoelectrocatalytic oxidation.
We have also discussed the use and feasibility of graphene
nanocomposites in water disinfection and desalination.
Finally, the future challenges and perspectives are discussed