锆基MOF孔道限域强化及其低碳烃吸附分离性能  

Pore Confinement Enhancing Strategy and Light Hydrocarbon Adsorptive Separation Performance of Zirconium-Based MOF

作　　者：刘金辉 周道浩 肖喻文 黄艳 张博 王伟[1] 郭子阳 李忠[1] 周欣[1] LIU Jin-hui;ZHOU Dao-hao;XIAO Yu-wen;HUANG Yan;ZHANG Bo;WANG Wei;GUO Zi-yang;LI Zhong;ZHOU Xin(School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510641,China;Guangzhou Hua Fang Tobacco Flavors Co.,Ltd.,Guangzhou 510530,China)

机构地区：[1]华南理工大学化学与化工学院,广州510641 [2]广州华芳烟用香精有限公司,广州510530

出　　处：《离子交换与吸附》2024年第2期147-156,I0003,共11页Ion Exchange and Adsorption

基　　金：国家自然科学基金项目(基金号22378138);广东省基础与应用基础研究基金项目(基金号2021A1515010119)。

摘　　要：从天然气中回收C2/C3低碳烃组分以及乙烯/乙烷、丙烯/丙烷的分离纯化具有重要的工业价值,吸附分离技术可以在常温常压下高效分离低碳烃。对金属有机骨架(Metal-Organic Framework,MOF)材料进行次级结构单元(Second Building Units,SBU)调控,构筑限域强化的碱性孔道化学微环境并引入新的吸附位点,可以提升其吸附分离性能。文章用三乙烯二胺(TED)取代Zr-TBAPy中SBU配位的水分子,制备了具有更大烷烃吸附容量和选择性的TED@Zr-TBAPy。其中,TED1/3@Zr-TBAPy表现出优先吸附烷烃的特征,丙烷/丙烯、乙烷/乙烯的理想吸附溶液理论(Ideal Adsorption Solution Theory,IAST)选择性分别为1.32、1.49,比Zr-TBAPy提高了15.7%和3.5%。常温常压下,丙烷/甲烷和乙烷/甲烷的IAST选择性分别达到287和14,比Zr-TBAPy提高了116%和19.7%,超过大部分已报道的同类材料。机理研究表明,TED的引入提高了孔道的限域吸附作用,同时引入对烷烃具有更强吸附作用的碱性新吸附位点TED,两者协同强化了孔道对烷烃的C—H^(δ+)…N^(δ-)静电相互作用,从而提高其对低碳烃的吸附选择性,进而为提高MOFs吸附剂的低碳烃分离性能提供了一种可行的通用策略。Recovering C2/C3 hydrocarbon components from natural gas and separating ethylene/ethane and propylene/propane are of significant industrial value.Adsorptive separation technology can efficiently separate hydrocarbons at ambient condition.The adsorption separation performance of MOF can be improved by regulating its secondary building unit(SBU)to construct the pore confinement,which enhances alkaline microenvironment with new adsorptive sites.In this work,TED@Zr-TBAPy adsorbents with higher alkane adsorption capacity and selectivity were prepared by replacing the water molecules from the SBU of Zr-TBAPy with triethylenediamine(TED).Among them,TED1/3@Zr-TBAPy showed the preferential adsorption for alkane,with the IAST selectivity of 1.32 and 1.49 for propane/propylene and ethane/ethylene,respectively,which were 15.7%and 3.5%higher than that of Zr-TBAPy.Besides,the IAST selectivity for propane/methane and ethane/methane under normal temperature and pressure reached 287 and 14,respectively,which were 116%and 19.7%higher than Zr-TBAPy,respectively,surpassing most adsorbents in literature.Mechanistic studies showed that the TED enhanced the pore confinement effect and introduced new alkaline adsorption site,which synergistically promoted the C-H^(δ+)…N^(δ-)electrostatic interaction between alkane adsorbate and adsorbent's pore,thereby improving the selective adsorption mechanism for light hydrocarbons.This work demonstrated a feasible and general strategy to enhance the adsorptive performance of MOF adsorbents for the separation and purification of light hydrocarbons.

关 键 词：烷烃选择性 金属-有机骨架 次级结构单元调控 吸附作用 低碳烃 

分 类 号：TQ028.1[化学工程]