Carbon coated CoO plates/3D nickel foam: An efficient and readily recyclable catalyst for peroxymonosulfate activation

Abstract

Constructing of the 3D porous structured catalyst with high efficiency and low metal ion dissolution is crucial for peroxymonosulfate (PMS) based advanced oxidation technologies (AOPs). In this work, carbon coated CoO plates/3D Ni foam catalyst was prepared by hydrothermal, carbon precursor coating and subsequently carbonization method. The obtained catalyst was further applied in the activation of PMS for the degradation of ofloxacin (OFX) and other organic pollutants in water. The physicochemical properties of the catalyst were systematically characterized, and the influence of several parameters such as catalyst and PMS dosage, initial pH and temperatures on the removal of OFX were investigated. Results showed that ∼ 100% of OFX (20 mg/L) could be degraded by the catalyst within 20 min through PMS activation. Besides, the catalyst is easy to be recovered and reused with high efficiency and low metal ion leaching. The quenching experiments and the results of EPR demonstrated both free (•OH, •SO4–, O2•–) and non-free radicals (1O2) were involved in the OFX degradation, and the cycle of Co2+/Co3+ and lattice oxygen on the catalyst surface were mainly responsible for efficient reactive oxygen species (ROS) generation from PMS. Finally, intermediate products in the OFX degradation process were identified, and possible degradation pathway and the mechanism were proposed.