Photocatalytic degradation of Rhodamine B using CoxZn1-xFe2O4 nanocomposite under visible light irradiation: Synthesis, characterization and its application

Abstract

Using Rhodamine-B (Rh B) as a model organic molecule, a co-precipitation-oxidation-mediated synthesis of cobalt-substituted zinc spinel ferrites (CoxZn1-xFe2O4, x = 0 to 1) is described. Multiple methods (XRD, DRS, EDX, VSM, BET, and FESEM) were used to evaluate the synthesized cobalt zinc ferrites. The material Co0.5Zn0.5Fe2O4, which had pore diameters ranging from 3 to 50 nm and a minor peak centered at about 35 nm, displayed non-uniform shapes and sizes of the porous materials made by the aggregation of ferrite nanoparticles. The SBET Brunauer-Emmett-Teller (BET)surface area values were 10.05, 13.47, and 10.9 m2/g for ferrites, zinc ferrites, and cobalt-zinc ferrites, respectively. It was found that under ideal conditions, 99% of the Rh B dye was destroyed by the Co0.3Zn0.7Fe2O4 (x = 0.3) sample within 180 min of exposure to visible light. Scavenger testing and fluorescence spectroscopy confirmed that OH and holes were the principal reactive radicals involved in the degradation process. The performance of a Co0.3Zn0.7Fe2O4 photocatalyst was almost unchanged after being cycled for five consecutive cycles. Therefore, it was concluded that these photocatalysts are superior options for treating Rh B-tainted wastewater under optimum conditions (pH = 2, dose catalyst = 0.1 mg/L, concentration of pollutant = 20 mg/L, with 120 mM of hydrogen peroxide).