School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, China.
Yancao Industry Biochar-Based Fertilizer Engineering Research Center of China, Bijie Yancao Company of Guizhou Province, Bijie, Guizhou 550700, China.
Sci Total Environ. 2024 Nov 15;951:174962. doi: 10.1016/j.scitotenv.2024.174962. Epub 2024 Jul 25.
Per- and polyfluoroalkyl substances (PFAS) present significant environmental and health hazards due to their inherent persistence, ubiquitous presence in the environment, and propensity for bioaccumulation. Consequently, the development of efficacious remediation strategies for soil and water contaminated with PFAS is imperative. Biochar, with its unique properties, has emerged as a cost-effective adsorbent for PFAS. Despite this, a comprehensive review of the factors influencing PFAS adsorption and immobilization by biochar is lacking. This narrative review examines recent findings indicating that the application of biochar can effectively immobilize PFAS, thereby mitigating their environmental transport and subsequent ecological impact. In addition, this paper reviewed the sorption mechanisms of biochar and the factors affecting its sorption efficiency. The high effectiveness of biochars in PFAS remediation has been attributed to their high porosity in the right pore size range (>1.5 nm) that can accommodate the relatively large PFAS molecules (>1.02-2.20 nm), leading to physical entrapment. Effective sorption requires attraction or bonding to the biochar framework. Binding is stronger for long-chain PFAS than for short-chain PFAS, as attractive forces between long hydrophobic CF-tails more easily overcome the repulsion of the often-anionic head groups by net negatively charged biochars. This review summarizes case studies and field applications highlighting the effectiveness of biochar across various matrices, showcasing its strong binding with PFAS. We suggest that research should focus on improving the adsorption performance of biochar for short-chain PFAS compounds. Establishing the significance of biochar surface electrical charge in the adsorption process of PFAS is necessary, as well as quantifying the respective contributions of electrostatic forces and hydrophobic van der Waals forces to the adsorption of both short- and long-chain PFAS. There is an urgent need for validation of the effectiveness of the biochar effect in actual environmental conditions through prolonged outdoor testing.
全氟和多氟烷基物质（PFAS）由于其固有持久性、在环境中普遍存在以及易于生物累积，对环境和健康构成重大危害。因此，开发针对受 PFAS 污染的土壤和水的有效修复策略至关重要。生物炭具有独特的性质，已成为 PFAS 的一种具有成本效益的吸附剂。尽管如此，对于影响生物炭对 PFAS 的吸附和固定的因素，仍缺乏全面的综述。本综述考察了最近的研究结果，这些结果表明，生物炭的应用可以有效地固定 PFAS，从而减轻其在环境中的迁移及其对生态系统的后续影响。此外，本文还综述了生物炭的吸附机制以及影响其吸附效率的因素。生物炭在 PFAS 修复方面的高效性归因于其在正确孔径范围内（>1.5nm）的高孔隙率，这可以容纳相对较大的 PFAS 分子（>1.02-2.20nm），从而导致物理捕获。有效吸附需要对生物炭骨架产生吸引力或键合。长链 PFAS 的结合比短链 PFAS 更强，因为长疏水 CF-尾部之间的吸引力更容易克服带负电的生物炭通常带负电的头基的排斥。本综述总结了案例研究和野外应用，突出了生物炭在各种基质中的有效性，展示了其与 PFAS 的强结合。我们建议研究应集中于提高生物炭对短链 PFAS 化合物的吸附性能。确定生物炭表面电荷在 PFAS 吸附过程中的重要性是必要的，同时量化静电作用力和疏水力范德华力对短链和长链 PFAS 吸附的各自贡献。迫切需要通过延长室外测试来验证生物炭效应在实际环境条件下的有效性。
