Zhang Zhuangzhuang, Zhao Haiqian, Wang Zhonghua, Hu Zhipei, Wang Qingshu, Meng Erlin, Lai Shiwei, Ying Jiaxin, Li Hongguang, Wu Chuanyan
School of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, Heilongjiang, 163318, China.
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, Jiangsu, 215009, China.
Environ Res. 2023 Nov 1;236(Pt 2):116794. doi: 10.1016/j.envres.2023.116794. Epub 2023 Jul 30.
The use of the electro-Fenton process to continuously generate HO and efficiently degrade organic pollutants is considered a promising technology. The ratio of generation of HO is usually regarded as the critical step; however, how the HO is utilized is also of particular importance. Herein, activated carbon was activated at different temperatures and used to explore the effect of nitrogen doping on the production and utilization of HO in the electro-Fenton-based degradation of organic pollutants. The experimental results indicate that nitrogen-doped activated carbon simultaneously promotes the generation and utilization of HO, which is attributed to the regulation of the competition between phenol and O adsorption by the doped nitrogen. Nitrogen doping not only improves 2eORR selectivity but also aggregates phenol near the cathode to balance the concentrations of phenol and ·OH. Density functional theory (DFT) calculations further confirmed that pyrrole-N as a dopant promoted the adsorption of phenol, while pyridine-N was more favorable for O adsorption. The unique balance of nitrogen types possessed by modified activated carbon NAC-750 permits the efficient synergistic generation and utilization of HO in a balanced manner during the degradation of phenol. This work provides a new direction for the rational nitrogen-doping modification of activated carbon for the electro-Fenton-based degradation of organic pollutants.
使用电芬顿工艺连续生成羟基自由基（HO）并有效降解有机污染物被认为是一项很有前景的技术。HO的生成比例通常被视为关键步骤；然而，HO的利用方式也尤为重要。在此，将活性炭在不同温度下进行活化，并用于探究氮掺杂对基于电芬顿降解有机污染物过程中HO生成及利用的影响。实验结果表明，氮掺杂活性炭同时促进了HO的生成和利用，这归因于掺杂氮对苯酚和氧吸附之间竞争的调节作用。氮掺杂不仅提高了2e氧还原反应（ORR）的选择性，还将苯酚聚集在阴极附近以平衡苯酚和·OH的浓度。密度泛函理论（DFT）计算进一步证实，作为掺杂剂的吡咯氮促进了苯酚的吸附，而吡啶氮更有利于氧的吸附。改性活性炭NAC - 750所具有的独特氮类型平衡，使得在苯酚降解过程中能够以平衡的方式高效协同生成和利用HO。这项工作为基于电芬顿降解有机污染物的活性炭合理氮掺杂改性提供了新方向。
