Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; Institute of Agriculture Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Chemosphere. 2020 Feb;240:124842. doi: 10.1016/j.chemosphere.2019.124842. Epub 2019 Sep 23.
With a wide range of raw materials, low cost and large specific surface area, biochar has been widely used in environmental remediation. However, the biochar has a saturated adsorption capacity when it is used as a pollutant adsorbent. Recent efforts have been made to prepare biochar and biochar-based catalysts with enhanced catalytic properties to expand their potential applications. The environmental persistent free radicals (EPFRs) of biochar could react with O to induce hydroxyl radicals (•OH) without the addition of oxidants. When oxidants were added, biochar and biochar-based catalysts could activate them to generate •OH and sulfate radicals (SO•), respectively. Moreover, biochar could act as an electron acceptor to improve the photodegradation capacity of catalysts. With reference to the information regarding biochar and biochar-based catalysts, this work provides a critical review on recent research development as follows: 1) the preparations of various types of biochar and biochar-based catalysts are summarized; 2) the effects of the synthetic conditions and transition metals on the catalytic activity of biochar-based catalysts are discussed; (3) methods for characterizing the active sites of the biochar-based catalysts are described; and (4) the environmental applications of biochar and biochar-based catalysts are discussed with regards to three aspects based on the interaction mechanisms, namely, oxidation, reduction, and photocatalysis. The synthesis conditions and loading of metal/metal-free catalyst are key parameters controlling the catalysis activity of biochar and biochar-based catalysts. This review provides new insights into the application of biochar in catalysis. Key challenges and further research directions are proposed as well.
生物炭具有原料来源广泛、成本低、比表面积大等特点，已广泛应用于环境修复中。然而，生物炭作为污染物吸附剂时，吸附容量达到饱和。因此，人们努力制备具有增强催化性能的生物炭和基于生物炭的催化剂，以扩大其潜在应用。生物炭的环境持久性自由基（EPFRs）可以与 O 反应，无需添加氧化剂即可诱导产生羟基自由基（•OH）。当添加氧化剂时，生物炭和基于生物炭的催化剂可以分别激活它们以产生•OH 和硫酸根自由基（SO•）。此外，生物炭可以作为电子受体来提高催化剂的光降解能力。本文参考了生物炭和基于生物炭的催化剂的相关信息，对近年来的研究进展进行了综述：1）总结了各种类型的生物炭和基于生物炭的催化剂的制备方法；2）讨论了合成条件和过渡金属对基于生物炭的催化剂催化活性的影响；3）描述了用于表征基于生物炭的催化剂活性位点的方法；4）从氧化、还原和光催化三个方面讨论了生物炭和基于生物炭的催化剂的环境应用，并讨论了基于相互作用机制的环境应用，即氧化、还原和光催化。合成条件和金属/无金属催化剂的负载是控制生物炭和基于生物炭的催化剂催化活性的关键参数。本文为生物炭在催化中的应用提供了新的见解。并提出了关键挑战和进一步的研究方向。
