Degradation of Hazardous Organics via Cathodic Flow-through Process Using a Spinel FeCo2O4/CNT Decorated Stainless-Steel Mesh

Tianzhu Fan,

Wei Deng,

Yang Gang,

Zichen Du,

Ying LiEmail

J. Mike Walker ’66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, 77843, USA

Abstract

Cathodic membranes were applied with Fe2+ reagent to enhance the mass transport of electro-Fenton (EF) by means of forced permeation. However, the considerable amount of toxic Fe2+ reagent left in electrolytes may cause secondary pollution. Also, the membranes without active EF catalysts exposed low removal efficiency due to insufficient surface catalytic activity. In this work, an advanced flow-through process without toxic Fe2+ reagent was developed using modified stainless steel (SS) mesh with high catalytic activity. The surface of SS mesh was decorated by catalytically-active FexCo3-xO4 nanoparticles and functionalized carbon nanotubes (CNTs). The synergistic effect between Fe and Co elements enhanced the electro-Fenton efficiency, and the optimal n(Fe): n(Co) ratio was determined at 1:2 from the degradation rate of pollutants and H2O2. The addition of FeCo2O4/CNT enhanced the first-order reaction rate k to 2.60 times on bisphenol A (BPA) removal, and 2.16 times on sulfamethoxazole (SMX) removal, compared to an undecorated mesh. Consequently, 94% of BPA were eliminated after 60 min and 100% of SMX were eliminated after 120 min, respectively, under a low current density of 2.84 mA cm-1. The total concentration of leached Fe/Co ions into the electrolyte was only around 2.4 μmol L-1 after the treatment.

Degradation of Hazardous Organics via Cathodic Flow-through Process Using a Spinel FeCo2O4/CNT Decorated Stainless-Steel Mesh