Chelating agents enhanced CaO2 oxidation of bisphenol A catalyzed by Fe3+ and reuse of ferric sludge as a source of catalyst

- CaO2 activated by Fe3+ was used as an oxidant for BPA degradation.
- With OA, 91.7% of Fe3+ was reduced comparing to CaO2/Fe3+ system.
- The ferric sludge was reused and successfully promoted BPA removal in CaO2/OA system.
- Acidification and chelation are responsible for the improved BPA removal.

The performance of calcium peroxide (CaO2) oxidation catalyzed by Fe3+ for the removal of bisphenol A (BPA) from aqueous solution was investigated. The ability of chelating agents (CAs), such as citric acid (CA), oxalic acid (OA), ethylenediaminetetraacetic (EDTA) and tartaric acid (TA), to accelerate the BPA degradation and to reduce the Fe3+ dosage was assessed. Furthermore, ferric sludge was reused as a source of catalyst to reduce solid waste accumulation. Results showed that the dosage of CaO2 and Fe3+ progressively influenced the BPA degradation and the optimal dosage was 2.0 mM CaO2 and 3.0 mM Fe3+. The addition of CAs effectively enhanced the BPA removal in CaO2/Fe3+ system and remarkably reduced Fe3+ utilization from 3.0 mM to 0.25 mM. BPA degradation increased from 21.3% (without CAs) to 98.3%, 98.9%, 95.5%, 95.0% with 1.0 mM CA, OA, EDTA and TA respectively. When 2.4 g/L ferric sludge was used as catalyst source, a 95.1% removal of BPA was achieved in the presence of OA. This study presents a high-impact contribution to Fenton-based wastewater treatment that can increase treatment efficiency and decrease waste sludge yield.