Activation potential decreasing of iron oxide/graphite felt cathode by introducing Mn in electrochemical Fenton-like reactions

Abstract

In electrochemical advanced oxidation processes (EAOPs), energy consumption cannot be ignored. In this work, Mn-Fe oxide/graphite felt (GF) cathodes were synthesized by in situ reduction and low temperature calcination. The obtained Mn-Fe oxide/GF was used as cathodes to activate peroxymonosulfate (PMS) for atrazine (ATZ) degradation in the EAOPs system. The minimal activation potential (η_min) of PMS was used to evaluate the activity of the cathodes, and it was found that the introduction of Mn element can effectively reduce the η_min of PMS on the Fe oxide/GF cathode. The energy consumption by optimized Mn-Fe oxide/GF can be decreased to ∼85.1% in the EAOPs system compared to that without Mn. In addition, the introducing of Mn can also enhance the activity and stability of the catalyst with decreased Fe leaching. Quenching experiments and electron paramagnetic resonance (EPR) test indicated that the EAOPs system could generate several reactive oxygen species (ROSs), including ^•OH, SO₄^•-, O₂^•- and ¹O₂. This work decreases the potential by introducing Mn and provides a method to reduce the energy consumption in EAOPs.

Keywords: Electrochemical activation; Energy conservation; Iron oxides; Minimal activation potential; Mn introducing; Peroxymonosulfate.