Efficient Removal of Emerging Contaminants by Radical and Non-Radical Activation of Peroxydisulfate in Conifc-Mof/Pds System

Abstract

In the study presented in this paper, a multimetallic ferrocene-based metal-organic framework (CoNiFc-MOF) catalyst with sea urchin-like structure was synthesized through a simple solvothermal method . We studied investigated the efficiency of persulfate (PDS) activated by CoNiFc-MOF catalyst to remove emerging contaminants. The findings showed that the removal efficiency of 10 mg/L bisphenol A (BPA) with CoNiFc-MOF catalyst reached over 98% within 5 min. Electron paramagnetic resonance (EPR) tests and radical trapping experiments indicated that the PDS activation process includes both radical oxidation and non-radical oxidation pathways. In this non-radical mechanism, BPA is oxidized via a direct electron transfer pathway mediated by the metastable reaction complex (CoNiFc-MOF/PDS*). The CoNiFc-MOF catalyst exhibited high removal efficiency, maintaining over 90% efficiency after five consecutive cycles, which reflects its exceptional catalytic activity and stability. The intermediates of BPA were further identified by liquid chromatography-mass spectrometry (LC-MS) and four potential degradation pathways were proposed. This catalyst also proved to be highly effective for bisphenol B (BPB), tetracycline (TC) and oxytetracycline (OTC) removal and the reaction rate closely linked to its structural characteristics and properties. Furthermore, the CoNiFc-MOF catalyst is characterized by a simple synthesis process and low cost, providing an effective design strategy for the development of efficient PDS-activated catalytic materials.

Keywords: Ferrocene-based metal-organic framework, Emerging contaminants, Bisphenol A, Peroxydisulfate, Radical and non-radical mechanism