精氨酸桥连的MOFs与氧化石墨烯复合吸附剂制备及烟气选择性固碳性能

Solid-phase adsorption method is selected for CO2 capture from coal-fired flue gas after efficient denitrification, desulfurization and dust removal. Combing the advantage of MOFs in CO2 storage, efficient and stable MOFs and graphene oxide composites bridged by L-Arginine are intended to be designed and synthesized. Cu-BTC with low cost, good stability and large-scale synthesis possibility is chosen as MOFs component. Through embedding highly dispersive layer graphene oxide into the framework structure of Cu-BTC, pore structure and pore size distribution was controlled and amount of the open Cu2+ sites was enhanced. Thus, pore utilization percentage and CO2 adsorption capacity was significantly improved. Further to solve the problem of poor selectivity of CO2 in MOFs, in view of the special molecular structure and rich groups of L- Arginine, Cu-BTC and graphene oxide is intended to be bridged by it. CO2 can be selectivity fixed in the new pores generated at the interface between Cu-BTC units and graphene oxide layers due to the introduction of guanidino active sites. The influence of preparation technology on the structure and chemical property of the composites will be studied. The correlation between the structure and chemical property and the CO2 adsorption performance will be established. The adsorption mechanism will be explored and properties of resistance to H2O are to be developed. All of these will be helpful for promoting industrialization process of the composite adsorbents.

针对燃煤电厂高效脱硫脱硝及除尘之后的净烟气，选择吸附法进行CO2捕集，结合MOFs材料在CO2储存领域的优势，设计和制备高效的L-精氨酸桥连的MOFs与氧化石墨烯复合吸附剂。选择成本低、稳定性好、易大规模合成的Cu-BTC作为MOFs组分，针对MOFs吸附小分子气体时孔道利用率低的现状，通过在其网络结构中嵌入高分散层状GO烯，实现孔结构的有效调控和开放Cu2+位点数目的增加，使CO2吸附容量显著提高。为进一步解决MOFs吸附CO2选择性差的问题，基于L-精氨酸特殊的分子结构与丰富的功能基团，采用L-精氨酸作为GO烯与Cu-BTC间的桥连剂，在Cu-BTC与GO烯界面处的新孔周围引入胍基等活性位，通过反应吸附定向选择性固定CO2。研究结构和化学性质可控的复合吸附剂制备工艺，建立吸附剂结构和活性基团性质与CO2吸-脱附性能间的相关性，探究吸附机理，挖掘吸附剂的抗水潜力，推进工业应用进程。

选择吸附法进行燃煤电厂烟气CO2捕集，结合MOFs材料在CO2储存领域的优势，设计和制备了高效的L-精氨酸桥连的MOFs与氧化石墨烯复合吸附剂。以成本低、稳定性好、易大规模合成的Cu-BTC作为MOFs组分，针对MOFs吸附小分子气体时孔道利用率低的现状，通过在其网络结构中嵌入高分散层状GO烯，实现了孔结构的有效调控和开放Cu2+位点数目的增加，使CO2吸附容量显著提高。同时，基于L-精氨酸特殊的分子结构与丰富的功能基团，采用L-精氨酸作为GO烯与Cu-BTC间的桥连剂，在Cu-BTC与GO烯界面处的新孔周围引入了胍基等活性位，通过反应吸附定向选择性固定CO2，进一步解决了MOFs吸附CO2选择性差的问题。与母体MOFs相比，改性复合吸附剂的CO2吸附容量和CO2/N2选择性分别提高了50%和15%以上。采用固定床吸附测试比较了吸附剂在不同温度、流量和湿度条件下的动态CO2吸附性能，获得了Cu-BTC/Bio-GO捕集CO2的较优工艺条件。研究发现H2O分子参与胍基位点与CO2的反应提高了复合吸附剂的抗湿性能。采用4种动力学模型拟合了Cu-BTC/Bio-GO在不同温度、不同流速、不同湿度下的CO2吸附行为。其中分数阶动力学模型是最合适的模型，该模型的拟合结果与实验结果最为吻合，揭示了Cu-BTC/Bio-GO的吸附机理为物理和化学共吸附。由于吸附剂的可重复使用性能对其能否工业应用尤为重要，因此在最佳温度、流量和高湿度条件下重复吸附10个循环。结果表明复合吸附剂循环再生利用性能大大改善，在高湿度条件下，10次循环吸脱附过程中，第10次相比第1次的吸附容量减少率从15%降低到6%。