Qu Chao, Li Yan-Gang, Meng Shu-Juan, Li Xiao-Hu, Zhang Shu-Jun, Liang Da-Wei
School of Space & Environment, Beihang University, Shahe Campus, Beijing 102206, China.
Beijing Drainage Group Co. Ltd (BDG), Beijing 100044, China.
J Hazard Mater. 2022 Jul 15;434:128923. doi: 10.1016/j.jhazmat.2022.128923. Epub 2022 Apr 14.
Recently, carbon nanotubes coated carbon black and polytetrafluoroethylene (CNTs-C/PTFE) gas diffusion electrode was used as an air-cathode in an electro-oxidation (EO) system for effectively generating hydrogen peroxide (HO) through a 2-electron oxygen reduction reaction (ORR). This ORR-EO system not only lowered applied voltage and conserved energy, but the synergistic peroxone (O/HO) reaction could increase hydroxyl radicals (OH) generation for organics elimination. However, a significant proportion of HO was left in the effluent of ORR-EO, which was a loss of resources and energy. In this study, a Fenton-like reaction for in-situ HO decomposition to generate active oxidation species was inserted by introducing MnO into the cathodic catalyst layer, and the sole MnO/CNTs-C/PTFE air-cathode could accomplish 90% of phenol degradation. When MnO/CNTs-C/PTFE air-cathode combined with Ti/NATO anode in an ORR-EO system, all anodic oxidation, Fenton-like reaction, and peroxone took place to successfully generate OH and singlet oxygen (O). Over 95% of TOC in phenol and landfill leachate bio-effluent was effectively eliminated, with 20% energy savings compared to the ORR-EO with CNTs-C/PTFE air cathode.
最近，碳纳米管包覆炭黑和聚四氟乙烯（CNTs-C/PTFE）气体扩散电极被用作电氧化（EO）系统中的空气阴极，通过两电子氧还原反应（ORR）有效生成过氧化氢（HO）。这种ORR-EO系统不仅降低了施加电压并节约了能源，而且协同过氧单硫酸盐（O/HO）反应可以增加用于消除有机物的羟基自由基（OH）的生成。然而，相当一部分HO留在了ORR-EO的流出物中，这是资源和能源的损失。在本研究中，通过将MnO引入阴极催化剂层，插入了一种类芬顿反应以原位分解HO来产生活性氧化物种，仅MnO/CNTs-C/PTFE空气阴极就能实现90%的苯酚降解。当MnO/CNTs-C/PTFE空气阴极与Ti/NATO阳极在ORR-EO系统中结合时，所有阳极氧化、类芬顿反应和过氧单硫酸盐反应都发生了，成功生成了OH和单线态氧（O）。苯酚和垃圾渗滤液生物流出物中超过95%的总有机碳（TOC）被有效去除，与使用CNTs-C/PTFE空气阴极的ORR-EO相比，节能20%。
