A novel cobalt-based complex as efficient peroxymonosulfate activator to degrade aqueous Rhodamine B, Methylene Blue and Methyl Orange

The sulfate radical-based advanced oxidation processes (SR-AOPs) have been attracting widespread attention due to their high selectivity and oxidative potential in wastewater treatment. The future SR-AOPs depend on the R & D of adequate catalysts with high activity and stability. As emerging catalysts, complexes have shown excellent performance in various fields due to their customisable structures and tunable coordination sites. In this study, a novel mixed ligand Co-CP catalyst, namely {[Co 2 (3,3′-azpd)(4,4′-oba) 2 (H 2 O) 8 ]·2H 2 O} n was assembled by using 3,3′-azopyridine and 4,4′-dicarboxydiphenyl ether as mixed ligands via the solvothermal method. The prepared Co-CP showed remarkable performance in activating peroxymonosulfate (PMS) and degrading organic dyes: it took only 14 min to catalyze the degradation of 97 % RB, 8 min to catalyze the degradation of 96 % MB, and 3 min to catalyze the degradation of 92 % MO. Its catalytic degradation efficiency exceeds that of most reported non-homogeneous catalysts. The experiments showed that the catalyst dosage, PMS concentration and the temperature all play key roles in the PMS activation. Moreover, RB degradation obeyed the pseudo-first order model with rate constant ranging from 0.0217 to 0.4639 min −1 . The prepared Co-CP showed stability after five recycling experiments, indicating that it can serve as a s highly efficient and stable catalyst for generating free radicals (such as ·SO 4 − , ·OH) to further treat organic dyes rapidly and provide more options for future wastewater treatment.