富氮金属有机骨架修饰生物炭捕集烟气中CO2协同SO2、NOx脱除机理研究

The emission reduction of CO2, SO2 and NOx in the flue gas is an important issue in the world. The nitrogen-enriched metal organic frameworks (MOFs) modified biochar can combine the advantages of nitrogen-enriched MOFs and porous biochar: low cost of preparation, developed pore structure, high surface chemical activity and easy directional controllability, which is quite suitable for a high quality adsorbent of flue gas purification. This project presents a process of the preparation of the nitrogen-enriched MOFs modified biochar and its application in CO2 capture with the simultaneous removal of SO2 and NOx in flue gas. The evolution regulation of nitrogen rich MOFs modified biochar’s pore structure, surface groups of species composition and distribution of nitrogen from whole process of nitrogen enriched MOFs modified biochar of the preparation to gaseous pollutants removal to its regeneration will be explored in this project. The microcosmic reaction characteristics of nitrogen-enriched MOFs modified biochar during pollutants capture in flue gas will be also studied to reveal the formation mechanism of the physicochemical characteristics on nitrogen-enriched MOFs modified biochar and the synergistic reaction mechanism of CO2 capture with the simultaneous removal of SO2 and NOx in flue gas. On these basis, combining the theoretical model and experimental verification, the theory and method of CO2 capture with the simultaneous removal of SO2 and NOx in flue gas by the nitrogen-enriched MOFs modified biochar would be established to optimize the process parameters. The research results of this project will be helpful to explore a new way to control atmospheric pollutants, and also provide scientific guidance for the development and application of high efficient and low-cost carbon-based adsorbent.

烟气中CO2、SO2、NOx减排是世界各国面临重要课题，富氮金属有机骨架（MOFs）修饰生物炭结合了富氮MOFs和多孔生物炭的优势，同时具有制备成本低廉、孔隙结构发达、表面化学活性高且易定向调控等特点，非常适宜成为优质的烟气净化剂。本项目创新性提出了一种富氮MOFs修饰生物炭捕集烟气中CO2协同SO2、NOx脱除的新工艺，旨在解析富氮MOFs修饰生物炭从制备到污染物脱除和再生全过程中其理化结构演变机理，探索富氮MOFs修饰生物炭捕集烟气污染物的微观反应规律，揭示富氮MOFs修饰生物炭捕集烟气中CO2联合脱除SO2、NOx的协同反应机制；在此基础上结合理论模型和实验优化，建立富氮MOFs修饰生物炭捕集烟气中CO2协同脱除SO2、NOx的理论和方法。本项目研究成果将有利于探索出一条大气污染物治理的新途径，为高效低成本碳基吸附剂开发和应用提供科学的指导。

烟气中CO2、SO2、NOx减排是世界各国面临重要课题，富氮MOFs修饰生物炭结合了富氮MOFs和多孔生物炭的优势，同时具有制备成本低廉、孔隙结构发达、表面化学活性高且易定向调控等特点，非常适宜成为优质的烟气净化剂。本项目完成了富氮金属有机骨架修饰生物炭的理化特性及形成机理研究，解析从制备过程到气态污染物脱除到再生全过程中富氮MOFs修饰生物炭孔隙结构、表面基团种类及分布的演变规律，研究了富氮MOFs修饰生物炭捕集烟气污染物微观反应机理，揭示富氮MOFs修饰生物炭理化特性形成机制和捕集烟气中CO2联合脱除SO2、NOx的协同反应机制，初步建立富氮MOFs修饰生物炭捕集烟气中CO2协同脱除SO2、NOx的理论和方法。经研究发现将ZIF-8接枝到生物炭上后，孔隙结构明显改善；当接枝量低时，接枝生物炭的面积和孔容增加了一倍；随着ZIF-8接枝量的增加，最大BET比表面积可增加5倍，达到1251.02 m2/g，总孔体积可扩大7倍以上，微孔体积可扩大3倍；此外，其氮含量可从原始0.02 at.%增加至25.02 at.%。其中ZIF-8/BC1-900是对CO2吸附性能最好的一种，吸附量可达107 mg/g；不同气体吸附难易程度可分为：SO2 > CO2 > NO ≈ NO2 > N2。MOFs修饰生物炭对于CO2和SO2的吸附能力远远大于对于NO的吸附，NO吸附最为困难；MOFs修饰生物炭对于CO2和SO2的吸附能力较于单独吸附实验中的有所下降，这说明了在吸附过程中，CO2和SO2存在着一定的竞争关系，而有NO存在时，对二者吸附有明显促进作用。本项目研究取得了丰硕的成果，共发表论文9篇，其中SCI 9篇，申请专利11项，授权8项；并且项目负责人在项目执行期内获得国际先进材料协会提名“碳材料与技术”2021年度杰出科学家奖；此外，以第一资助标注成果“Physicochemical and adsorption properties of biochar from biomass-based pyrolytic polygeneration: effects of biomass species and temperature”发表在我国自主SCI一区国际权威期刊《Biochar》上论文被“炭索未来”公众号科普宣传；本项目成果将有利于高效低成本碳基吸附剂的制备提供新方法。