Insights into the activation of peroxymonosulfate by ZIF-L@ZIF-67 derived CoCN catalyst for highly effective removal of phenol in the presence of chloride ions

A novel catalyst with cobalt and nitrogen-codoped porous carbon matrix (CoCN-900) was successfully prepared, characterized and applied for activating peroxymonosulfate (PMS) to remove phenol in aqueous solution. The CoCN-900 material exhibited superior performance in activating PMS for phenol degradation and could completely remove phenol within 60 min. Radical quenching tests and electron paramagnetic resonance (EPR) analysis showed that 1O2 and SO4•– played a major role in the phenol removal process over the CoCN-900/PMS system. In addition, the influences of catalyst/PMS dose, initial phenol concentration, reaction temperature, natural organic matter and coexisting anions on phenol degradation were systematically investigated. Particularly, it was found that the chloride ions (Cl–) had a significant accelerative effect, increasing the phenol degradation rate from 0.142 to 0.600 min−1. In the presence of Cl–, the phenol degradation efficiency was primarily ascribed to the effects of 1O2 and O2•–, which were significantly different from those in the absence of Cl–. Meanwhile, Cl– could also accelerate the deactivation of the catalyst. Findings in this study provided new insight for the fabrication of high-performance zeolitic imidazolate frameworks (ZIFs)-derived carbon materials and evaluating the influences of anions on the degradation of phenolic contaminants in PMS-based advanced oxidation processes (AOPs).