Nanotechnology in water and wastewater treatment. Graphene – the nanomaterial for next generation of semipermeable membranes.

In recent decades, novel and promising graphene-based materials (i.e., carbon nanotubes, nanoporous graphene and graphene oxide) suitable to be used in preparation of high-capacity membranes for water desalination and water and wastewater treatment have been developed. After detail recognition of properties of nanoporous graphene and graphene oxide-based materials, the general conclusion on preparation of membranes made of only graphene or only graphene oxide as well as other composite materials involving these nanomaterials has been given. Novel composite membranes containing nanoporous graphene and, first of all, graphene oxide can be divided into two groups: (i) freestanding membranes made only of graphene or only of graphene oxide, and (ii) polymeric/ceramic membranes modified with the use of graphene-based nanomaterials. The modification of polymeric membranes can be achieved either by introduction of a nanomaterial onto a membrane surface or its addition to a membrane casting solution followed by membrane formation from a polymer and a nanomaterial mixture. Membranes based on nanomaterials enable to obtain significantly higher water/permeate fluxes than currently used thin film composite polyamide membranes. The future prospect of membranes based on nanoporous graphene and graphene oxide in regard to the final separation efficiency and commercial scaling up has been discussed. [ABSTRACT FROM AUTHOR]