Swiss-roll electrodes for efficient degradation of carbofuran by electrochemical advanced oxidation processes

Abstract

Electrochemical advanced oxidation processes (EAOPs) have been extensively investigated for the degradation of emerging contaminants. However, only the composition of electrodes is well studied but less for the electrode configuration. This work developed a new configuration of electrodes rolled along the optimized Archimedes spirals shaping a “Swiss roll”. The effects of electrode distance, electrode area and current were investigated via regulating the electrode configuration and EAOPs conditions. The increasing electrode distance contributed to the H2O2 accumulation but went against the anodic oxidation of carbofuran. The EAOPs with moderate electrode distance showed synergetic removal of carbofuran by electro-Fenton and anodic oxidation processes. The current density was optimized by changing electrode area and current. The increasing current density promoted the generation of H2O2 and •OH, which could significantly improve the removal of carbofuran by electro-Fenton process. Accordingly, novel kinetic models were developed and validated with experimental data to describe the coupled electro-Fenton and anodic oxidation reactions. Examination of transformation products indicated that the continuous production of •OH accelerated the cleavage and ring-opening of carbofuran and transformation products. The reactor consumed low electrical energy (34.4 kWh/kg) in long-term EAOPs, providing promising solutions in terms of performance and cost in large-scale applications.