Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China.
Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China.
Chemosphere. 2021 Sep;279:130456. doi: 10.1016/j.chemosphere.2021.130456. Epub 2021 Mar 31.
Recent studies suggested that biochars could mediate the degradation of organic contaminants. The role of biochars in mediating organic contaminant degradation could be amplified in a Fenton-like reaction, and comparing biochars with varied properties may provide insightful information to understand the reaction mechanisms. In this study, biochar was applied in a Fenton-like reaction system with Fe and persulfate (PS) to degrade 2,4-dichlorophenel (2,4-DCP). Biochars with different intensities of persistent free radicals (PFRs), oxygen-containing functional groups (OFGs), and redox properties were investigated regarding their roles in 2,4-DCP removal. Compared to biochar system, PS addition increased 2,4-DCP degradation and Fe addition increased its sorption. The combination of PS and Fe promoted 2,4-DCP degradation over 2 times higher. Various reactive oxygen species (ROS), including SO, HO, and O, were involved in 2,4-DCP degradation, contributing to around 50% of the overall 2,4-DCP degradation. The direct electron transfer between biochar particles and 2,4-DCP contributed to the rest of 2,4-DCP degradation. A significant positive correlation was observed between 2,4-DCP degradation and electron donating capacity (EDC) or Fe. We thus concluded that EDC-involved structures in biochars could either directly donate electron to 2,4-DCP, or reduce Fe to Fe, which activated PS to generate ROS. This dual roles of biochar should be well considered in biochar application and production. This study provided a useful theoretical basis for manipulating biochar redox properties to enhance their application potential in pollution control.
最近的研究表明，生物炭可以介导有机污染物的降解。在类芬顿反应中，生物炭在介导有机污染物降解中的作用可以被放大，并且比较具有不同性质的生物炭可能提供深入了解反应机制的信息。在这项研究中，生物炭被应用于包含铁和过硫酸盐（PS）的类芬顿反应体系中，以降解 2,4-二氯苯酚（2,4-DCP）。研究了具有不同持久性自由基（PFRs）、含氧官能团（OFGs）和氧化还原性质的生物炭在 2,4-DCP 去除中的作用。与生物炭体系相比，PS 的添加增加了 2,4-DCP 的降解，而铁的添加增加了其吸附。PS 和铁的组合促进了 2,4-DCP 的降解，使其降解率提高了 2 倍以上。各种活性氧物质（ROS），包括 SO、HO 和 O，参与了 2,4-DCP 的降解，对 2,4-DCP 的总降解贡献了约 50%。生物炭颗粒与 2,4-DCP 之间的直接电子转移对 2,4-DCP 的其余部分降解做出了贡献。2,4-DCP 降解与电子供体能力（EDC）或铁之间存在显著的正相关关系。因此，我们得出结论，生物炭中涉及 EDC 的结构可以直接将电子供体转移到 2,4-DCP 上，或者将铁还原为 Fe，从而激活 PS 产生 ROS。生物炭的这种双重作用在生物炭的应用和生产中应该得到很好的考虑。本研究为操纵生物炭氧化还原性质以增强其在污染控制中的应用潜力提供了有用的理论基础。
