农林废弃物制备炭微球结构调控及其选择性吸附VOCs研究

PM2.5 air pollution issues are increasingly serious which make humans to face the tough challenges in their survival environment. Volatile Organic Compounds (VOCs) as a source of PM2.5 have been widely considered, which is one of the major air pollutants in the world. Porous carbon microspheres as adsorptive materials have been shown huge potential in VOCs removals due to their advantages in fast absorption rates, low flow resistance, strong adsorption selectivity. This project provides a new route for preparation of carbon spheres by utilization of cellulose extracted from agricultural and forestry residues as carbon source. Hydrothermal carbonization added with phosphoric acid activation method is used for preparations. The effect of preparation conditions on the microcrystalline structure, morphology, particle size, surface area, pore structure and surface chemical properties of carbon spheres will be investigated. The methods to control the pore structures of carbon spheres are developed. The chemical methods such as nitrogen reagent and oxidant are employed to modify the surface carbon microspheres. The influence of modification conditions on the surface functional groups, pore structure and surface area are systematically studied. To explain the structure-activity relationship between the pore structure and adsorption performance, the selective adsorption properties of multicomponent VOCs on carbon microspheres will be performed, in terms of adsorption capacity, breakthrough curve and adsorption isotherm. This project aimed to study the preparation methods of carbon microspheres with controlled pore and selective adsorption properties. Agricultural and forest residues based carbon spheres should be potentially sustainable materials applied in adsorption field and will provide technical support in industrial applications.

日趋严重的PM2.5空气污染是人类赖以生存环境的严峻挑战，而作为其祸首挥发性有机化合物（VOCs）成为世界公认的主要空气污染物之一。炭微球多孔性材料因其吸附速率快、流动阻力小、吸附选择性强等优点，在治理VOCs技术方面存在巨大潜力。本项目利用农林废弃物提取纤维素为碳源，采用水热炭化结合磷酸活化法制备炭微球，探索水热炭化、磷酸活化等因素对炭微球的微晶结构、形貌、粒径均一、比表面积、孔隙结构、表面化学性能影响，形成新型炭微球孔隙调控基础理论。通过加入含氮试剂和氧化剂等化学方法对炭微球表面进行修饰，分析不同改性工艺对其表面官能团、孔隙结构和比表面积的影响。研究炭微球对多组分VOCs的选择性吸附量、穿透曲线和吸附等温线，阐明其孔结构与吸附性能之间的匹配构效关系；探讨修饰后炭微球对VOCs的选择性吸附性能。本项目旨在研究孔隙可调控和选择性吸附炭微球的制备方法，为炭微球在吸附领域的产业化应用奠定基础。

日趋严重的PM2.5空气污染是人类赖以生存环境的严峻挑战，而作为PM2.5的祸首挥发性有机化合物（VOCs）成为世界公认的主要空气污染物之一。炭微球多孔性吸附材料因其吸附速率快、流动阻力小、吸附选择性强等优点，在治理VOCs技术方面存在巨大潜力。本项目利用农林废弃物提取纤维素和酶解木质素为碳源，采用水热炭化结合磷酸活化法制备炭微球，探索了水热炭化、磷酸活化等因素对炭微球的微晶结构、形貌、粒径均一、比表面积、孔隙结构、表面化学性能的影响，得到了高比表面积、孔隙发达、表面光滑、粒径均一微米级炭微球，形成了新型炭微球孔隙调控基础理论。通过加入含氮试剂和氧化剂等化学方法对炭微球表面进行修饰，探索了HNO3和HNO3/ H2O2不同改性剂对其表面官能团、形貌、分散性的影响，研究表明，单独的HNO3的改性对炭微球表明惰性不明显，然而，经过HNO3/H2O2的修饰，炭微球表面被氧化，并且-COOH引入了炭微球的表面，提高了其亲水性，从而最终团聚现象得到大大改善，分散性得到大幅度提高。采用固体核磁技术探索了吸附VOCs后的炭微球，VOCs 与炭微球的相互作用机制，重点研究了不同VOCs浓度和吸附时间对固体核磁谱图位移和强度的影响，分别采用传统的气体吸附仪和固体核磁技术研究了炭微球对VOCs的吸附等温线，发现两者吸附量和吸附曲线一致，证明了固体核磁技术可以成功、快捷地测试VOCs在炭微球上的吸附等温线。本项目成功研发了一种具有孔隙可调控和选择性吸附炭微球的制备方法，为扩大了炭微球在吸附领域的产业化应用提供技术支撑。