Energy-efficient removal of carbamazepine in solution by electrocoagulation-electrofenton using a novel P-rGO cathode

In this study,carbamazepine(CBZ) decay in solution has been studied by coupling electrocoagulation with electro-Fenton(EC-EF) with a novel P-rGO/carbon felt(CF) cathode,aiming to accelerate the in-situ generation of ·OH,instead of adding Fe2+and H2O2.Firstly,the fabricated P-rGO and its derived cathode were characterized by XRD,SEM,AFM,XPS and electrochemical test(EIS,CV and LSV).Secondly,it was confirmed that the performance in removal efficiency and electric energy consumption(EEC) by EC-EF(kobs=0.124 min-1,EEC=43.98 kWh/kg CBZ) was better than EF(kobs=0.069 min-1,EEC=61.04 kWh/kg CBZ).Then,P-rGO/CF(kobs=0.248 min-1,EEC=29.47 kWh/kg CBZ,CE=61.04%) showed the best performance in ECEF,among all studied heteroatom-doped graphene/CF.This superior performance may be associated with its largest layer spacing and richest C=C,which can promote the electron transfer rate and conductivity of the cathode.Thus,more H2O2and ·OH could be produced to degrade CBZ,and almost 100% CBZ was removed with kobsbeing 0.337 min-1and the EEC was only 24.18 kWh/kg CBZ,under the optimal conditions(P-rGO loading was 6.0 mg/cm~2,the current density was 10.0 mA/cm~2,the gap between electrode was 2.0 cm).Additionally,no matter the influent is acidic,neutral or alkaline,no additional pH adjustment is required for the effluent of EC-EF.At last,an inconsecutive empirical kinetic model was firstly established to predict the effect of operating parameters on CBZ removal.