Bisphenol-S removal via photoelectro-fenton/H2O2 process using Co-porphyrin/Printex L6 gas diffusion electrode

Abstract

The present work reports the development and application of gas diffusion electrode (GDE) based on carbon Printex L6 modified with 5% Co-Porphyrin/CPL6 for the removal of Bisphenol S (BPS) in wastewater using different electrochemical advanced oxidation processes (EAOPs). The application of the modified GDE led to the in-situ generation of 333 mg L−1 of H2O2 in only 90 min; this represents an increase of 88% in H2O2 generation in relation to the unmodified GDE. The process involving bisphenol S degradation fitted well into a pseudo-first order kinetic reaction for all the treatment techniques evaluated; the treatment techniques investigated recorded an increase in kinetic rate constant in the following order: anodic oxidation (0.004 min−1) < UV-C (0.006 min−1) < H2O2 (0.008 min−1) < H2O2/UV-C (0.016 min−1) < electro-Fenton (0.063 min−1) < photo electro-Fenton (0.154 min−1). The photo electro-Fenton (PEF) process exhibited the best degradation efficiency; BPS was completely removed after only 30 min of treatment and 78% mineralization was recorded after 360 min of treatment. The remaining organic matter under the PEF treatment process corresponded to short-chain carboxylic acids; this confirms the efficiency of the process applied for BPS decontamination. The results obtained show that the proposed treatment mechanism can be successfully combined with cheaper biological treatments for a total remediation of wastes.