Synergistic Adsorption-Photocatalytic Degradation of Methyl Green by Magnetic Fe3O4/CMC@Cysteine-ZnO Nanocomposite

The synergy technology of adsorption-photocatalysis has become a new trend for eliminating organic pollutants. The present work reports a well-designed adsorption-photocatalysis bifunctional nanocomposite, Fe3O4/CMC@Cysteine-ZnO, for removing methyl green (MG) dye molecules. Compared with NH2-Fe3O4 and Fe3O4/CMC@Cysteine, Fe3O4/CMC@Cysteine-ZnO showed excellent performance for the removal of MG. MG was quickly adsorbed on the surface of the functional magnetic polymer and rapidly degraded by ZnO nanoparticles under visible light irradiation, indicating the synergistic effect of adsorption and photocatalysis. According to the results, after adsorption for 40 min and visible light irradiation for 10 min, approximately 99.6% of MG was removed by the nanocomposite at optimum conditions of feed pH, catalyst dosage, and initial dye concentration. In addition, the photocatalytic dye degradation obeyed the pseudo-first-order kinetic model, and the nanocomposite revealed reproducible performance after 5 repetitive cycles. Therefore, Fe3O4/CMC@Cysteine-ZnO nanocomposite with high performance, recyclability, and easy magnetic separation is very promising for MG removal and other pollutants from the wastewater.