Photo-activation of persulfate and hydrogen peroxide by humic acid coated magnetic particles for Bisphenol A degradation

摘要

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, center dot OH and SO4 center dot- 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.