Multifunctional crosslinked chitosan/nitrogen-doped graphene quantum dot for wastewater treatment

Abstract

The fabrication of multifunctional nanomaterial for the adsorption of different types of pollutants is a challenge and could be a solution for many problems associated with wastewater treatment. This current study propose the use of crosslinked chitosan/nitrogen doped-graphene quantum dot nanocomposites (CS/NGQD) synthesized via glutaraldehyde as cross-linker to remove various pollutants including bacteria, proteins, fluoride, dyes, and pharmaceuticals. This nanomaterial was characterized using different techniques (FT-IR, XRD, SEM, TEM, and Raman spectroscopy). This nanocomposite offered higher pollutants removal efficiencies compared to its component parts. Using CS/NGQD the removal reached 60% for proteins and 88% for the bacterial load. A significant removal enhancement was also obtained for pharmaceuticals (63% for chlorothiazide, 81% for carbamazepine, and 89% ranitidine), dyes (82% for Azo blue, 84% for methylene blue and 94% for orange G), and fluoride (42%). Interestingly, after 5 cycles of reuse, the nanocomposite remains efficient for the removal of pollutants from water.