Cobalt tetracarboxyl phthalocyanine-manganese octahedral molecular sieve (OMS-2) as a heterogeneous catalyst of peroxymonosulfate for degradation of diclofenac.

A composite of cobalt tetracarboxyl phthalocyanine and amino-functionalized manganese octahedral molecular sieve (CNOMS-2) was synthesized in a simple way, and applied for degrading diclofenac in aqueous media by catalyzing of peroxymonosulfate heterogeneously. The experiment results revealed that the CNOMS-2/PMS system was highly efficient for DCF degradation in the pH range of 5-9, and the mechanism involved the generation of OH, SO4⁻ and 1O2 by the activation of PMS. The main reactive oxygen species was found to be 1O2 by radical scavenging experiments and electron paramagnetic resonance (EPR) spectroscopy. Further, a carboxylation product of DCF at m/z 340 was found to be a prominent intermediate of the reaction in this system specially, as determined by LC-MS/MS. The reusability and ion leaching concentrations under different pH were also examined to determine the application prospects of the catalyst.