Two-dimensional graphitic carbon nitride-based membranes for filtration process: Progresses and challenges

Two-dimensional (2D) graphitic carbon nitride (g-C3N4) membranes with lamellar structure have gained extensive attention in the past decade due to their good separation performance. Studies carried out on the filtration performance in the fields of Microfiltration, Ultrafiltration, Nanofiltration, Reverse and Forward osmosis reveal that 2D g-C3N4-based membranes have a high selectivity towards all kinds of contaminants present in water such as organic components as well as divalent and monovalent ions while maintaining high permeability and that by their photocatalytic properties they are able to remedy the membrane fouling thus allowing long-term use over several cycles of filtration process. Therefore, the limitations encountered by conventional polymeric membranes have thus been corrected by the use of 2D nanomaterials-based membranes such as g-C3N4. This review mainly focuses on summarizing recent trends in research on g-C3N4 nanosheets-based membrane filtration, including g-C3N4 nanosheets and membrane fabrication, composition and application. We also attempt to provide future directions in which the field is likely to be realized. The key challenges and issues related to the synthesis and application of g-C3N4-based membranes in the filtration field are highlighted.