Electrochemical activation of peroxymonosulfate using chlorella biochar modified flat ceramic membrane cathode for berberine removal: Role of superoxide radical and mechanism insight

Both the low-cost biomass biochar and reactive electrochemical membrane (REM) have been proved as a feasible method for persulfate electro-activation. However, the biochar modified REM, especially be use as cathode for persulfate activation, was rarely reported. To this end, the electro-activation of peroxymonosulfate (PMS) for treating berberine hydrochloride (BH) was performed by a novel polyacrylonitrile cross-linked chlorella biochar (CBC-700) modified flat ceramic membrane (FCM) cathode. Results revealed that the applied electric field, CBC-700/FCM and PMS establish an excellent synergetic effect in the CBC-700/FCM + PMS integrated electrocatalytic oxidation-filtration system. High graphitizing and N-doping defect degree of CBC-700/FCM facilitate PMS electro-activation. Reactive species quenching and EPR experiments demonstrated the co-generation of OH, SO4∙- and 1O2, while 1O2 formed with O2∙-/HO2- as the crucial precursor provided more contribution (52.6%) to BH removal. The tolerance experiments against inorganic anions, humic acid and different water matrixes affirmed the excellent anti-membrane fouling ability and the practical applicability of CBC-700/FCM. Finally, the degradation pathways of BH was also proposed based on the results of LC/MS.