Elimination of bisphenol A with visible light-enhanced peroxydisulfate activation process mediated by Fe3+-nitrilotriacetic acid complex

In recent years, visible light assisted advanced oxidation processes (AOPs) are appealing in the elimination of pollutants. Herein, an innovative and eco-friendly visible light enhanced Fe3+-nitrilotriacetic acid system for the activation of peroxydisulfate (Vis/Fe3+-NTA/PDS) was proposed for the removal of bisphenol A (BPA). Fe3+-NTA could be dissociated through ligand-to-metal charge transfer (LMCT) to realize the generation of Fe2+ for the continuous activation of PDS to remove BPA. The use of 0.10 mM Fe3+, 0.10 mM NTA and 1.00 mM PDS led to 97.5% decay of 0.05 mM BPA and 66.3% of TOC removal in 30 min with the illumination of visible light at initial pH 3.0. The sulfate and hydroxyl radicals were proved to be the dominant species leading to BPA removal by means of radical scavenging experiments, radical probes and electron paramagnetic resonance (EPR) technique. The effects of various operating parameters, natural water constituents as well as different water matrices on BPA abatement were explored. The intermediate products of BPA degradation were identified and a possible transformation pathway was proposed. Briefly, this research provides an attractive strategy for the remediation of refractory wastewater using NTA assisted with visible light in the homogeneous Fe3+/PDS system.

Automated summary

In recent years, visible light assisted advanced oxidation processes (AOPs) have gained attention in pollutant removal. This study proposes an innovative and eco-friendly system, visible light enhanced Fe3+-tris(2-aminoethyl)amine (Fe3+-NTA)/peroxydisulfate (PDS), for the removal of bisphenol A (BPA). Through ligand-to-metal charge transfer (LMCT), Fe3+-NTA can activate PDS to generate Fe2+ and remove BPA. The results demonstrate that under visible light illumination, efficient BPA removal can be achieved using the appropriate concentrations of Fe3+, NTA, and PDS.