Yongjun Song,Yi Zhou,Dongli Guo,Yahui Shi,Jiawei Liang,Haoran Li,Dongjin Wan
An innovative ACF/CC@FeOCl-assisted FTEF-SR system was established. • FeOCl-Cu served as catalyst for the electro-Fenton and as a PMS activator. • The primary generated reactive oxygen species were • OH and SO 4 · − . • Preferential removal of sulfamethoxazole was achieved in different water matrices. • The system exhibits good stability and energy-saving performance. Sulfamethoxazole (SMX), a representative sulfonamide antibiotic contaminant, poses significant environmental risks. Peroxymonosulfate (PMS) activation-driven electro-Fenton (EF) processes have attracted considerable attention for the removal of organic pollutants from water. In this study, a flow-through heterogeneous EF system integrated with PMS activation (FTEF-SR) was developed using a FeOCl-Cu-modified carbon cloth cathode for the efficient degradation of SMX. The FTEF-SR system exhibited broad pH adaptability and excellent recyclability. Under optimized conditions, near-complete removal of SMX (>99%) was achieved within 60 min. Meanwhile, the effects of catalyst dosage and ratio, current, PMS concentration, electrolyte type, pH, as well as initial concentration were systematically investigated. At a current density of 9 mA cm⁻ 2 and a PMS concentration of 1 mM, SMX and total organic carbon (TOC) removal reached 98.9% (30 min) and 80.2% (180 min), respectively. Moreover, the real-world water matrix and common coexisting ions did not significantly inhibit the removal efficiency of SMX, still maintaining above 92%, indicating that this coupling method was feasible in real application. Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that • OH and SO 4 •– dominated the degradation of SMX in the FTEF-SR system. Overall, this work not only advances the development of efficient and sustainable wastewater purification technologies but also provides valuable mechanistic insights for the degradation of antibiotic contaminants. Download: Download high-res image (478KB) Download: Download full-size image
The utilization of hybrid electro-Fenton (EF) processes has gained considerable attention, which can combine the advantages of two or more treatment methods resulting in efficient removal of refractory pollutants from water. Here, an electro-controlled membrane coupling heterogeneous EF (EM-HEF) system was constructed for the degradation of acetaminophen (APAP) in water. In the EM-HEF system, a bifunctional ACF/CC-FeOCl-Cu cathode material was synthesized to enhance the HEF reaction, while a tubular Ti microfiltration membrane was used as both cathode and membrane. Degradation experiments indicated the EM-HEF system exhibited remarkable removal efficiency (97.0 %) towards APAP within 30 min under the conditions of flow rate at 60 mL min −1 , initial pH at 7.1, and current density at 3 mA cm −2 . Notably, the cathode materials showed low metal leaching rate and high APAP removal rate in the 10 cyclic experiments. The common inorganic anions (Cl − , HCO 3 − , HPO 4 2− , and NO 3 − ) did not inhibit the removal of APAP significantly, whereas humic acid exhibited a more pronounced inhibitory effect only at concentrations exceeding 10 mg L −1 . Quenching experiments and electron spin resonance (ESR) tests confirmed the pivotal role of hydroxyl radicals in the decomposition of APAP. Combining density functional theory (DFT) and LC-MS results, three pathways were proposed. The overall toxicity of intermediates was relieved during EM-HEF degradation of APAP. Furthermore, it also achieved good performance in the treatment of landfill leachate, with increasing BOD 5 /COD ratio from 0.11 to 0.34. This work provides an efficient strategy for the removal of refractory pollutants in water.