Activation of peroxymonosulfate by CoS2 loaded air-laid cloth for rapid degradation of organic pollutants in a shallow continuous flow reactor

Abstract

Activation of peroxymonosulfate by heterogeneous catalyst is an efficient process for organic pollutants removal. However, it is difficult for solid-liquid separation of the heterogeneous catalysts in slurry-like batch reaction. In this work, CoS2 particles were deposited onto an air-laid cloth (denoted as CoS2-ALC) and were used as a catalyst for activation of peroxymonosulfate (PMS). Unlike traditional slurry-like batch reaction forms, a shallow continuous flow reactor was designed for the installation of a CoS2-ALC, thereby improving the activation efficiency of persulfate and rapid solid-liquid separation. The degradation kinetics constant for carbamazepine (CBZ) by the CoS2-ALC/PMS process was 0.0748 min−1, which is 374, 150, 150 times higher than that the CoS2-ALC adsorption process, PMS/ALC oxidation process and PMS alone process, respectively. The significantly enhanced degradation efficiency was due to the S in CoS2 promoting the cycling of Co2+/Co3+, thereby enhancing the generation of free radical. Parameters such as CoS2 deposition amount, PMS concentration, water flow rate, water flow height, water flow direction, solution pH, humic acid and anions that affecting the degradation efficiencies were studied. In addition, the degradation by-products of CBZ as well as their toxicity were detected, and a possible degradation pathway were proposed. Finally, expanded outdoor experiments and cycling experiment demonstrated that the CoS2-ALC/PMS process is potentially useful in practical settings of wastewater treatment.