Efficient removal of oxytetracycline hydrochloride by ZIF-67 coated hollow spherical CuS (CuS-PVP@ZIF-67) under the synergistic effect of adsorption and PMS activation

Abstract

Selective removal of organic pollutants by PMS-activated heterogeneous catalytic system has become one of the commonly used methods, but the adsorption of the catalyst is often ignored in the degradation process. Metal-organic frameworks (MOFs) are often used in the field of environment because of their high porosity and structural diversity/adjustability. However, there are still difficulties in the aggregation and recycling of nanoparticles. This study effectively synthesized the material CuS-PVP@ZIF-67 by using hollow spherical CuS as the carrier of Co-MOF (ZIF-67) to solve these problems. A high concentration of oxytetracycline hydrochloride (OTC) can be successfully adsorbed by electrostatic attraction and π-π interaction, and small amount of PMS may be quickly activated, and the removal rate of OTC is 94.82 % in 20 min. The catalyst used can be easily recovered by suction filtration and has good reusability. In addition, a potential cooperating mechanism for adsorption-PMS activation has additionally been proposed. The degradation pathway of OTC is determined, and the potential harm of intermediate products is analyzed. This work aims to create a heterogeneous catalytic system with significant adsorption and catalytic ability to remove refractory organic contaminants in water.