Insights into the mechanism of persulfate activation with carbonated waste metal adsorbed resin for the degradation of 2,4-dichlorophenol

作者：Zhou, Shuang; Hu, Yonglian; Yang, Minglei; Liu, Yun; Li, Qingke; Wang, Yanhong; Gu, Guohua^*; Gan, Min^*

来源：Environmental Research, 2023, 226: 115639.

DOI：10.1016/j.envres.2023.115639

• Persulfate
• Fe@C/Cu@C
• Sulfate radical
• Hydroxyl radical
• Superoxide radical
• Redox cycling

Superabsorbent resin (SAR) saturated with heavy metals poses a threat to surrounding ecosystem. To promote the reutilization of waste, resins adsorbed by Fe2+ and Cu2+ were carbonized and used as catalysts (Fe@C/ Cu@C) to activate persulfate (PS) for 2,4-dichlorophenol (2,4-DCP) degradation. The heterogeneous catalytic reaction was mainly responsible for 2,4-DCP removal. The synergistic effect of Fe@C and Cu@C was propitious to 2,4-DCP degradation. Fe@C/Cu@C with a ratio of 2:1 showed the highest performance of 2,4-DCP removal. 40 mg/L 2,4-DCP was completely removed within 90 min under reaction conditions of 5 mM PS, pH = 7.0 and T = 25 degrees C. The cooperation of Fe@C and Cu@C facilitated the redox cycling of Fe and Cu species to supply accessible PS activation sites, enhancing ROS generation for 2,4-DCP degradation. Carbon skeleton enhanced 2,4-DCP removal via radical/nonradical oxidation pathways and via its adsorption to 2,4-DCP. SO4-, HO and O-2(center dot-) were the dominate radical species involved in 2,4-DCP destruction. Meanwhile, the possible pathways of 2,4-DCP degradation were proposed based on GC-MS. Finally, recycling tests proved catalysts exhibited recyclable sta-bility. Aiming to resource utilization, Fe@C/Cu@C with satisfactory catalysis and stability, is promising catalyst for contaminated water treatment.