吸附法捕集CO2是实现工业尾气中CO2分离和脱除的重要技术。固体胺吸附剂由于优异的CO2吸附容量和选择性及较低的再生能耗被广泛研究。传统粉末吸附剂由于压降大等问题，需成型加工才能应用于实际工业过程。但整型吸附剂仍面临吸附性能不足、机械性能差等问题。以大孔环氧树脂聚合物为模板、正硅酸乙酯为硅源，采用牺牲模板法制备整型大孔SiO2，并在其基础上负载四乙烯五胺（TEPA）开发整型大孔SiO2基固体胺吸附剂。整型大孔SiO2材料以交联的中空SiO2微球为骨架，具有典型的大孔结构，且TEPA均匀分布在骨架表面。TEPA负载量为70%的70T-MS样品在75 ℃、0.1 MPa（12% CO2/88% N2）条件下，CO2吸附量高达191 mg/g，经50次吸脱附循环可稳定在160 mg/g以上。动态吸附试验表明，其CO2吸附动力学遵循Avrami模型，说明其受传质扩散限制影响较小。整型大孔SiO2基固体胺吸附剂机械强度可达0.72 MPa（轴向）和30.30 N/cm（径向），满足工业吸附剂要求。吸附剂还具有良好的热稳定性和较低的热容（2.79 J/(g·℃)），有望实现低能耗再生。

Capturing CO2 by adsorption method is an important technology to realize the separation and removal of CO2 from industrial exhaust gas. Solid amine adsorbents have been widely explored due to its excellent adsorption capacity and selectivity of CO2, and low energy consumption for desorption. In fact, traditional powder adsorbents can only be used after molding in actual industrial processes due to its large pressure drop and other problems. However, monolithic adsorbents still face challenges such as insufficient adsorption capacity and poor mechanical properties. Herein, using macroporous epoxy resin polymer as template and tetraethyl orthosilicate as silicon source, the monolithic macroporous SiO2 was prepared by sacrificial template method. On this basis, the monolithic macroporous SiO2-based solid  amine adsorbent was obtained by impregnating different amount of tetraethylene pentaamine (TEPA). The monolithic macroporous SiO2 material takes the cross-linked hollow SiO2 microspheres as the skeleton, which has  a typical macroporous structure, and TEPA is evenly distributed on the surface of the skeleton. Under 75 ℃ and 0.1 MPa (12% CO2/88% N2), the CO2 adsorption capacity of 70T-MS sample with 70% TEPA loading is up to 191 mg/g, which can be stably maintained  above 160.0 mg/g even after 50 adsorption-desorption cycles. Dynamic adsorption results show that the CO2 adsorption kinetics follow the Avrami model, indicating that the adsorption process is less affected by mass transfer diffusion limitations. Furthermore, the mechanical strength of the adsorbents can reach 0.72 MPa (axial) and 30.30 N/cm (radial), meeting the requirements of industrial adsorbents. Moreover, the adsorbents also exhibit excellent thermal stability and low heat capacity (2.79 J/(g·℃)), which is expected to achieve  low-energy desorption and regeneration.

0 引言

1 试验

   1.1 试验材料及试剂

   1.2 整型大孔环氧树脂聚合物的制备

   1.3 整型大孔SiO2材料的制备

   1.4 整型大孔SiO2基固体胺吸附剂的制备

   1.5 材料表征方法

   1.6 CO2吸脱附性能测试

2 结果和讨论

   2.1 吸附剂宏观和微观形貌

   2.2 吸附剂结构性质

   2.3 CO2吸附性能

   2.4 吸附动力学研究

   2.5 吸附剂热稳定性

   2.6 吸附剂机械强度性能

   2.7 吸附剂热容

3 结论