Recent advances in the application of carbon nitrides for advanced water treatment and desalination technology

Carbon nitride (CN) and its different derivatives have received increased research consideration in current materials science because of its extensive range of potential applications in environmental protection. At present, the graphitic CN (g-C3N4), an important two-dimensional layered material, has been used in different areas like energy conversion, photocatalysis, and environmental contamination management. Its derivatives have also drawn huge research attention because of its intrinsic characters of their stable chemical and physical properties, eco-friendly nature, and inexpensive feature. This review focuses on the recent studies discussing the application of CNs for desalination and water treatment. In this study, the membrane-based application, photocatalytic application, adsorption application, and electrode-based application of CNs for water treatment and desalination have been discussed. In the membrane-based application, the use of microporous g-C3N4, microporous C2N, and microporous C3N for desalination (reverse osmosis, forward osmosis, nanofiltration), pervaporation, ultrafiltration, oil-in-water separation, and dye separation have been detailed. Moreover, the photocatalytic degradation of organic pollutants (dyes, pharmaceuticals, etc.) and metal ions by CNs have been examined in detail. Further, the adsorption application of CNs for the adsorption of dyes, metal ions, and surfactants has been studied. It was noted that CN and its different derivatives are suitable candidates as membrane materials, photocatalysts, adsorbents, and electrode materials for their effective application in desalination and water treatment.