A flow-through electro-Fenton process using modified activated carbon fiber cathode for orange II removal.

This study investigated the removal of Orange II by an electro-Fenton process using a novel recirculation flow-through reactor. The hydrogen peroxide was generated in-situ on the activated carbon fiber (ACF) modified with carbon black and polytetrafluoroethylene (PTFE). The modified ACF cathode was characterized by scanning electron microscopy (SEM) and nitrogen adsorption-desorption study. In light of the production of H2O2 and removal of Orange II, the optimum weight percentage of PTFE in the mixture of carbon black and PTFE was 75%. The effects of some important operating parameters such as current and flow rate were investigated. The best Orange II removal reached 96.7% with mineralization efficiency of 55.4% at 120 min under the current of 100 mA, initial pH 3, Fe2+ 0.3 mM and the flow rate of 7 mL min-1. The cathode exhibited good regeneration ability and stability. OH was proved to be the main oxidizing species in this flow-through electro-Fenton system. This work demonstrated that such electro-Fenton process using modified ACF cathode was promising for the degradation of organic pollutants.