Synthesis and Characterization of Graphene Oxide and Chitosan Decorated Nano Zerovalent Iron for Efficient Adsorptive Removal of Hazardous Azo Dye from Aqueous Medium

Abstract

The main aim of the study was to synthesize nano zerovalent iron (NZVI) modified with graphene oxide (GO) and chitosan (CS) in the form of a magnetic ternary nanocomposite. Three ternary nanocomposites i.e. GO-CS-NZVI, GO-NZVI-CS and CS-NZVI-GO were synthesized to further understand the possible binding tendencies among these components in the final ternary composite. These ternary composites were characterized by FTIR, SEM and EDS techniques to understand the effect of mutual interaction of the three components during synthesis on the overall structure and morphology of the ternary composite. Furthermore, these ternary nanocomposites were employed in the removal of Congo red (an anionic, carcinogenic, azo dye) and also a mixture of dyes Congo red and Rhodamine B (a cationic, carcinogenic dye). A maximum of 98% removal of Congo red and 98.7% removal from the mixture of dyes was observed with ternary nanocomposite GO-CS-NZVI within 30 min. Equilibrium adsorption efficiency (qe) was calculated to be 48.15 and 79 mg/g for Congo red and mixture of dyes (Congo red & Rhodamine B), respectively. A comparative analysis of bare NZVI with these ternary nanocomposites was also conducted to further understand the effect of modification of NZVI with graphene oxide and chitosan on the structure, morphology and its dye removal efficiency.