Constructing stainless steel felt-based SnO2-Sb anodes for highly efficient tetracycline wastewater degradation

Abstract

Electrocatalytic oxidation technology can degrade organic pollutants into tractable intermediates or directly into H2O and CO2. Exploiting efficient anode material is a hot topic in the field of organic wastewater degradation. Stainless steel felt (SSF), with its 3D structural properties, has great potential as an alternative substrate material for dimensionally stable anodes (DSAs). Herein, an SSF/SnO2-Sb anode was constructed by electrodepositing SnO2-Sb coating on the SSF substrate for tetracycline (TC) wastewater degradation. Under optimal process parameters, the resulting SSF/SnO2-Sb (1.5At%Sb) anode achieved high catalytic efficiency with a removal rate of 88.3% for TC and a COD removal rate of 80.6% for TC and its intermediates after 3 h treatment in simulated wastewater. Importantly, the SSF/SnO2-Sb anode showed superior stability due to the formation of FeSn and FeSn2 alloy between the SnO2-Sb coating and the SSF substrate. Detailed investigation revealed that ·OH radicals generated on the anode surface play a critical role in TC degradation and elaborated possible pathways for TC degradation based on intermediates. In addition, the intrinsic mechanism for TC degradation was also summarized. This work provides an efficient and stable SSF-based DSA material for organic wastewater degradation.