Synergistic Effect of Nitrogen-Doped on the Generation and Utilization of ·Oh in Electro-Fenton System with Activated Carbon Cathode

Abstract

In the electro-Fenton system with activated carbon as cathode, different nitrogendoped types have different effects on the decomposition of H2O2 to generate ·OH and the promotion of adsorption and degradation to formaldehyde. Regulating different nitrogen-doped types to achieve the synergy of generation and utilization of ·OH is the key to formaldehyde degradation. In this paper, the effects of nitrogen-doped types on the adsorption capacity of activated carbon for formaldehyde and H2O2, the ability of H2O2 activation to generate ·OH, and the mechanism of formaldehyde degradation by ·OH were explored. The results show that the pyridinic nitrogen promoted the adsorption of H2O2 on the cathode by hydrogen bonding. Pyrrolic nitrogen and graphite nitrogen promote the adsorption capacity for formaldehyde and the ability for H2O2 to activate ·OH. Pyridinic nitrogen and pyrrolic nitrogen promote the ability for ·OH to degrade pollutants. Through reasonable nitrogen-doped type, the efficient synergy of the generation and utilization of ·OH in the electro-Fenton system is realized. Under the experimental conditions, the formaldehyde degradation rate by the electro-Fenton system with nitrogen-doped cathode is 66.91% higher than that of the electro-Fenton system with unmodified cathode, which provides a new perspective for the formaldehyde treatment by the electro-Fenton system.

Keywords: activated carbon, nitrogen-doped, Formaldehyde, ·OH, density functional