Cuprous-mediated peroxymonosulfate activation for Fenton-like removal of micropollutants: The function of co-catalyst and the accelerated degradation mechanism

Abstract

Introducing co-catalysts to enhance the activation of cuprous-mediated peroxymonosulfate (PMS) and induce the continuous generation of highly reactive oxygen species is promising. The function, effectiveness, and acceleration mechanism of co-catalysts in the cuprous-mediated PMS activation process were fully explored in this work, which focused on rhodamine B as the target contaminants. The results demonstrated that molybdenum (Mo) powder was a superb co-catalyst, and that the reaction of cuprous-mediated PMS system was carried out by surface Mo species as opposed to Mo ions in the solution. The Cu (II)/Cu(I) cycle was primarily encouraged by the Mo⁰, which also caused abundant ·HO and ¹O₂ and minimal SO₄·^- and ·O₂^- to be produced from PMS. The Mo/Cu²⁺/PMS system exhibited high removal efficiency towards typical pollutants, especially ciprofloxacin, methyl orange, malachite green, and crystal violet, with removal rates up to 93%, 99%, 97%, and 92%, respectively. Additionally, this system showed excellent adaptability to complex water environments. After four cycles, the Mo powder retained its properties and morphology, and the target pollutants could still maintain an 82% degradation efficiency. This study provides a basis for enhancing cuprous-mediated PMS activation for wastewater treatment.