Performance and oxidation mechanism of H2O2/NaClO synergistic system on hypophosphite treatment in wastewater
In this study,hypophosphate(H2PO2-)in wastewater was selected as the target pollutant.The performance for H2PO2 oxidation to orthophosphate(PO43-)via varies methods including hydrogen peroxide(H2O2),sodium hypochlorite(NaClO)and H2O2/NaClO synergistic system were compared.It was found that H2O2/NaClO synergistic system had the best performance on the oxidation of H2PO2-to PO43-.The radical quenching experiments and electron spin resonance(ESR)spectroscopy results proved that ClO-,·OH,·O2 and 1O2 were contributable to the oxidation of H2PO2- to PO43-in the H2O2/NaClO synergistic system,and the key active species was 1O2.The effects of H2O2 concentration,NaClO concentration,initial solution pH,coexisting inorganic anions(SO42-,NO3-,HCO3 and Cl-),coexisting organic anions citrate(C6H5O73-)and humic acids(HA)on the oxidation efficiency of H2PO2- to PO43-by the H2O2/NaClO synergistic system was investigated.The results indicated that the production of PO43-was 88％at 120 min when the initial concentration of H2PO2- was 1.0 mmol·L-1,the dosages of NaClO and H2O2 were 50 mmol·L-1,and the initial solution pH was 5.In this reaction system,SO42-,NO3-,HCO3-and Cl-caused hardly significant effect on the oxidation of H2PO2-,while C6H5O73-and HA concentration could have the inhibitory effects.Finally,phosphorus was recovered via forming FePO4 precipitates by adding Fe3+to the generated PO43-wastewater in an acidic medium(pH＜4.3).Finally,the applicability of this system for treatment of actual wastewater containing H2PO2-was confirmed.This study can provide a reference for the treatment of industrial wastewater containing H2PO2-.
国家科技期刊平台
NSTL
万方数据
