Carbonized Foam Supported Co3O4 Activated Peroxymonosulfate Towards Rhodamine B Degradation

Abstract

Co3O4 has received much attention because of its excellent performance in activating peroxymonosulfate. However, the practical application of Co3O4 has been seriously restricted by the problems of agglomeration of Co3O4, difficult separation, easy loss, and poor recycling. In this study, the CMF/Co3O4 heterogeneous catalyst was prepared using the hydrothermal method. The crystal structure and morphology of CMF/Co3O4 were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Rhodamine B (RhB) degradation was employed as a model test for evaluating potassium peroxymonosulfate (PMS) activation. The degradation rate of RhB can reach 98% in the catalyst dosage of 35 mg·L-1, PMS concentration of 50 mg·L-1, pH of 7, and RhB initial concentration of 10 mg·L-1 after a 30 min reaction. The results showed that the degradation rate of RhB could be significantly improved by increasing the amount of CMF/Co3O4 heterogeneous catalyst and the mass concentration of PMS. The degradation rate of RhB can be inhibited by increasing the initial mass concentration of RhB and pH value. The process of degradation of RhB can be fitted by using the pseudo first-order kinetics model. The effect of temperature on the degradation rate of RhB conformed to the Arrhenius model, and the degradation process was a surface reaction-controlled process. The results of the free radical capture experiment showed that the sulfate radicals were the dominant active species for RhB degradation. After four cycles, the degradation rate of RhB still remained above 93% with CMF/Co3O4 catalyst.