Degradation of dimethyl phthalate by heterogeneous electro-Fenton process using Fe₃O₄-doped biomass porous carbon

Homogeneous electro-Fenton technology is a promising approach for treating the increasing numbers of refractory organic pollutants in water. However, it has disadvantages, such as a narrow pH usage range and the generation of secondary pollution during the actual treatment process. In this study, waste wine lees were used as biomass carbon precursors to prepare nitrogen and oxygen co-doped biomass carbon-loaded Fe₃O₄ composites (Fe₃O_₄@NOPC), thus constructing a heterogeneous electro-Fenton system to solve such problems. The results showed that the porous structure and rich surface functional groups of biomass carbon can act as carrier and accelerate the intermediate mass transfer. The degradation efficiency of dimethyl phthalate (DMP) reached 70% within 5 h by doping Fe³⁺/Fe²⁺ at the ratio of 2:1 without an additional of iron source; the conversion of Fe³⁺ to Fe²⁺ can be accelerated by an appropriate ratio. The degradation mechanism indicated that in addition to •OH radicals, a part of electro-oxidation and adsorption act together to play a degradation role. During the initial electro-Fenton reaction, the loaded Fe₃O₄ nanoparticles act as an iron source to reduce the production of iron-containing sludge and avoid secondary pollution. This provides a completely new idea to reduce the cost of electro-Fenton, effectively utilize waste resources, and reduce sludge production. Copyright © 2023 The Author(s).