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 center dot 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 (k(obs) =0.124 min(-1), EEC=43.98 kWh/kg CBZ) was better than EF (k(obs) =0.069 min(-1), EEC=61.04 kWh/kg CBZ). Then, P-rGO/CF (k(obs)= 0 . 248 min -1 , EEC=29.47 kWh/kg CBZ, CE=61.04%) showed the best performance in EC-EF, 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 H2O2 and center dot OH could be produced to degrade CBZ, and almost 100% CBZ was removed with k(obs) being 0.337 min(-1) and 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. (C) 2021 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Automated summary

This study investigated the decay of carbamazepine (CBZ) in solution using a novel P-rGO/carbon felt (CF) cathode coupled with electrocoagulation and electro-Fenton (EC-EF). The study found that the performance of EC-EF with P-rGO/CF was superior to EF alone in terms of removal efficiency and electric energy consumption. Additionally, an empirical kinetic model was established to predict the effect of operating parameters on CBZ removal.