Photo-Activation of Persulfate and Hydrogen Peroxide by Humic Acid Coated Magnetic Particles for Bisphenol A Degradation

Abstract Magnetic particles (MPs) coated with humic acid (HA) prepared under anoxic atmosphere were tested as heterogeneous photo-Fenton catalyst for the activation of hydrogen peroxide (H2O2) and persulfate (S2O82-) using Bisphenol A (BPA) as a model pollutant. The role of HA coating, pH value and H2O2/S2O82- concentration were investigated. A positive contribution of HA coating on H2O2 and S2O82- activation was found. The highest BPA degradation rates were achieved at acidic conditions (pH 3) with both H2O2 and S2O82-, however persulfate showed a significant efficiency even at pH 6, interesting feature in the light of decreasing the wastewater treatment costs. By the addition of selective quenching agents, •OH and SO4•– were identified as the main reactive species involved in the BPA abatement. An important contribution of the S2O82- photolysis on the overall BPA transformation was highlighted. The reuse of the catalyst was investigated and similar efficiency using H2O2 and S2O82- activation was observed until the third catalytic cycle. Experiments carried out using real wastewater samples, showed a good, even if less efficient compared to pure water, BPA removal