Interfacial engineering of bimetallic sulfides-based Al2O3 pellets with remarkably boosted peroxymonosulfate activation

Abstract

Accelerating the redox of Mn+/Mn+1 (M = metal) and enhancing the electron transfer efficiency is of great challenges in peroxymonosulfate activation. In this study, Al2O3 pellets were used as the support due to their excellent mechanical strength and thermodynamic stability. FeCoS@Al2O3 pellets were firstly prepared via in-situ assembly of ZIF-67 and Al2O3 pellets, followed by hydrothermal treatment and further sulfuration. Oxygen vacancy (OV) is a kind of anion defect attributed to lattice oxygen detachment under specific conditions. A series of characterizations and experiments confirmed that FeCoS@Al2O3 pellets possessed more abundant vacancies. Especially, the production of sulfur species remarkably strengthened the conversion of Fe3+/Co3+ to Fe2+/Co2+ that achieved 0.1985 min−1 degradation rate towards tetracycline (TC), which was higher than those of other reported catalysts. More significantly, a fluidized-column catalytic unit endowed the continuous zero discharge of TC with a flowing rate of 5 mL/min. Besides, the mechanism study indicated that the degradation pathway followed an order: 1O2 > O2·- > SO4·- > ·OH. This work provided a generally applicable method to design removable and highly efficient heterogeneous catalysts for wastewater treatment.