Continuous flow-through electro-Fenton membrane reactor with Fe−N4-doped carbon membrane as cathode for efficient removal of dimethylacetamide

• Published in: Separation and purification technology 2025-02, Vol.354, p.129290, Article 129290
• Main Authors: Zhu, Yuxuan, Chen, Zishang, Wang, Hong, Ma, Aijing, Li, Jianxin
• Format: Article
• Language: English
• Subjects: Conductive carbon membrane; Continuous flow-through electro-Fenton membrane reactor; Dimethylacetamide; Fe−N4-doped; Oxygen reduction reaction
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.129290

[Display omitted] •FeCM displayed small pore size, high porosity, and large specific surface area.•Fe − N4 enhanced DO adsorption energy and the performance of DMAC removal.•The Fe atom was the active site for adsorption and catalysis.•EFMR could continuously electrogenerated high concentration ·OH (89.1 mg/L)•EFMR enhanced FeCM mass transfer to improve DMAC degradation. Fe − N4-doped conductive carbon membranes (FeCMs) were fabricated through high-temperature carbonization using chitosan and phenolic resin as the raw materials and ammonium ferrous sulfate (NH4Fe(SO4)2) as the dopant. The impact of the NH4Fe(SO4)2 doping rate (0 − 15 wt%) on the structure and performance of the FeCM was investigated. Moreover, a continuous flow-through electro-Fenton membrane reactor (EFMR) was constructed using an FeCM cathode and a Ti plate anode for the efficient removal of dimethylacetamide (DMAC). The resultant carbon membrane with 10 wt% NH4Fe(SO4)2 (M10) exhibited a smaller pore size (40.1 nm), a higher porosity (48.3 %), a larger specific surface area (531.6 m2/g), and a higher mechanical strength (6.7 M Pa) than the other membranes. The removal rate of DMAC by EFMR with M10 as the cathode at 2 V reached 42.1 %, which was much greater than that without NH4Fe(SO4)2 (3.6 %). The electrosynthesis ·OH concentration by EFMR with M10 as the cathode was approximately 89.1 mg/L, which was much greater than that of most carbon-based materials. The intermediates of DMAC degradation (such as N-methylacetamide, acetamide, acetaldehyde, and acetic acid) were determined by gas chromatography–mass spectrometry (GC–MS), and the removal of total organic carbon (TOC) was approximately 3.4 %. Density functional theory (DFT) calculations revealed that the Fe atom served as the active site for dissolved oxygen adsorption and electrogeneration of ·OH. After 5 days of continuous EFMR operation, the DMAC removal rate remained at 88.8 % of the initial value (42.1 %). This study presents a novel approach for designing and fabricating conductive carbon membranes to improve industrial wastewater treatment performance.