Synergistic catalysis by Fe3O4-biochar/peroxymonosulfate system for the removal of bisphenol a

Abstract

• Adsorption and catalysis of BPA synergistically occurred in Fe 3 O 4 -BC/PMS system. • The biochar obtained by the pyrolysis of deciduous leaves of Platanus orientalis. • The enrichment of BPA on the surface was realized because of the biochar. • SO 4 •- was the mainly reactive radical species in Fe 3 O 4 -BC/PMS system. • Fe 3 O 4 -BC composite remained highly efficient in reuse experiments. The nanoFe 3 O 4 -biochar (Fe 3 O 4 -BC) heterogeneous catalyst was synthesized by coprecipitation method and the mechanism of Fe 3 O 4 -BC/peroxymonosulfate (Fe 3 O 4 -BC/PMS) system adsorption and synergistic catalysis for the removal of bisphenol A (BPA) were studied. The effect of initial pH, Fe 3 O 4 -BC load, PMS concentration on the catalyst activity were systematically evaluated. The results showed the synergistic effect between BC and Fe 3 O 4 can greatly improve the removal efficiency of BPA in the Fe 3 O 4 -BC/PMS system. BPA removal efficiency gained 100% in 90 min at pH 3.0 with PMS 5 mM, Fe 3 O 4 -BC load 2.0 g/L and BPA 20 mg/L. Sulfate radical (SO 4 •− ) and hydroxyl radicals ( • OH) was determined as the reactive species in the Fe 3 O 4 -BC/PMS system, and SO 4 •− was the major reactive species. Fe 3 O 4 -BC remained high active and the iron loss was only 2.13 mg/L when the pH was 3.0 after five recycles, which indicates that Fe 3 O 4 -BC catalyst has a good reusability potential and practical applications.