Enhanced degradation of ultra-violet stabilizer Bis(4-hydroxy) benzophenone using oxone catalyzed by hexagonal nanoplate-assembled CoS 3-dimensional cluster

Abstract

As UV-light stabilizers, Bis(4-hydroxy)benzophenone (BBP), are extensively consumed to quench radicals from photooxidation, continuous release of BPs into the environment poses serious threats to the ecology in view of their xenohormone toxicities, and BBP shall be eliminated from water to avoid its adverse effect. Since sulfate radical (SR)-based chemical oxidation techniques have been proven as effective procedures for eliminating organic emerging contaminants, this study aims to develop useful SR-based procedures through activating Oxone for degrading BBP in water. In contrast to the conventional Co3O4, cobalt sulfide (CoS) is particularly proposed as an alternative heterogeneous catalyst for activating Oxone to degrade BBP because CoS exhibits more reactive redox characteristics. As structures of catalysts predominantly control their catalytic activities, in this study, a unique nanoplate-assembled CoS (NPCS) 3D cluster is fabricated via a convenient one-step process to serve as a promising heterogeneous catalyst for activating Oxone to degrade BBP. With NPCS = 100 mg/L and Oxone = 200 mg/L, 5 mg/L of BBP can be completely eliminated in 60 min. The catalytic activity of NPCS towards Oxone activation also significantly surpasses the reference material, Co3O4, to enhance degradation of BBP. E-a of BBP degradation by NPCS-activated Oxone is also determined as a relatively low value of 42.7 kJ/mol. The activation mechanism as well as degradation pathway of BBP degradation by NPCS-activated Oxone was investigated and validated through experimental evidences and density functional theory (DFT) calculation to offer valuable insights into degradation behaviors for developing SR-based processes of BBP degradation using CoS catalysts.