CO₂作为主要的温室气体，对全球生态系统造成了巨大影响。生物炭因其原料来源广泛、制备成本低廉等原因，被认为是一种具有成本效益的CO₂吸附剂，但原始生物炭的结构特性和表面化学性质较差，所以需要对其理化性质进行调整。本综述从生物炭的理化性质出发，对生物炭的制备及改性方法进行了系统的分析，并在前人研究的基础上，对生物炭吸附CO₂的机理进行了总结。着重分析了改性过程中生物炭孔隙结构和表面化学性质等的变化对其CO₂吸附性能的影响。此外，还探讨了生物炭作为CO₂吸附剂在大规模CO₂捕集中可能存在的问题，以及未来研究的主要方向，旨在为改性生物炭CO₂吸附剂的制备及应用提供理论依据。

As the main greenhouse gas, CO₂ has a great impact on the global ecosystem. Biochar is considered to be a cost-effective CO₂ adsorbent because of its wide sources of raw materials and low preparation cost. However, the original biochar has poor structural characteristics and surface chemical properties, so its physical and chemical properties need to be adjusted. Based on the physicochemical properties of biochar, the preparation and modification methods of biochar were systematically analyzed in this paper. On the basis of previous studies, the mechanism of CO₂ adsorption by biochar was summarized. The influence of the changes of pore structure and surface chemical properties of biochar on its CO₂ adsorption performance during modification was emphatically expounded. In addition, the possible problems of biochar as CO₂ adsorbent in large-scale CO₂ capture and the main research directions in the future were also discussed, aiming at providing theoretical basis for the preparation and application of modified biochar CO₂ adsorbent.