多极性位点的杂化氢键有机框架吸附分离CO_(2)/CH_(4)  

Hybrid hydrogen-bonded organic frameworks with multi polar sites for adsorptive separation of CO_(2)/CH_(4)

作　　者：刘莹[1] 郑芳 陈俐吭 杨启炜[1,2] 张治国 任其龙[1,2] 鲍宗必 Ying Liu;Fang Zheng;Lihang Chen;Qiwei Yang;Zhiguo Zhang;Qilong Ren;Zongbi Bao(Key Laboratory of Biomass Chemical Engineering of Ministry of Education,College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,China;Institute of Zhejiang University-Quzhou,Quzhou 324000,China)

机构地区：[1]浙江大学化学工程与生物工程学院,生物质化学工程教育部重点实验室,杭州310027 [2]浙江大学衢州研究院,衢州324000

出　　处：《科学通报》2023年第28期3746-3757,共12页Chinese Science Bulletin

基　　金：国家自然科学基金(22225802,22288102,22141001,21878260);浙江省自然科学基金(LZ22B060002)资助。

摘　　要：氢键有机框架(HOFs)是极具研究价值的新型多孔材料,但稳定、永久多孔且富含功能位点的HOFs的构筑难题制约了其在气体吸附分离领域的应用.本文采用具有轮桨立体构型和多氢键位点的金属-核碱基构造体构筑了一类稳定的微孔杂化HOFs材料(HOF-ZJU-201、HOF-ZJU-202和HOF-ZJU-203),框架内的无机阴离子、氨基以及电荷差异性分布孔道作为多重极性位点实现了CO_(2)的选择性吸附和CO_(2)/CH_(4)的吸附分离.在298 K和1 bar(1 bar=105 Pa)条件下,杂化HOFs材料的CO_(2)吸附量为2.31~3.35 mmol/g,对CO_(2)/CH_(4)(50/50,v:v)的分离选择性为7.3~9.0.通过色散矫正的密度泛函理论计算和Hirshfeld表面分析明确了杂化HOFs材料通过氢键、静电偶极作用以及范德华力选择性捕获CO_(2)的作用机理.固定床穿透实验进一步验证了杂化HOFs材料对CO_(2)/CH_(4)的动态吸附性能,能够从等摩尔二元混合气中直接获得纯度99.9%的甲烷,具有低浓度甲烷气高效提浓的应用潜力.杂化HOFs材料良好的空气、水汽、热稳定性以及优异的循环稳定性和化学稳定性使其具备工业化应用潜力.Hydrogen-bonded organic frameworks(HOFs)are emerging as a promising class of crystalline organic solids due to their favorable attributes such as gentle synthesis conditions,facile purification,and regenerative capabilities.However,their applications across diverse domains,notably within adsorptive separation,has been limited by the relatively low bond energy inherent to hydrogen bonds.Consequently,the exploration of HOFs featured with high stability,permanent porosity,and functional sites has taken on a pivotal role within materials science and chemistry engineering.Natural gas,predominantly composed of CH_(4),presents a compelling alternative to conventional fossil fuels.Nevertheless,the presence of CO_(2)within natural gas undermines its calorific value and introduces operational complications.Moreover,the direct utilization of low-grade methane gases,such as landfill gas,is challenged by their high CO_(2)concentrations.Effectively capturing CO_(2)and effecting CO_(2)/CH_(4)separation are of paramount significance to foster the expansive advancement of natural gas applications while curtailing emissions from subpar methane sources.In the contemporary landscape,HOFs offer a novel platform to engineer and refine efficient adsorbents,capitalizing on their varied topologies and adaptable modifiability.The strategic integration of polar sites within hydrogen-bonded frameworks,achieved through the incorporation of polar anions and controlled manipulation of charge distribution across pore surfaces,stands to substantially amplify the performance of HOFs in CO_(2)adsorption and CO_(2)/CH_(4)separation.Nevertheless,the repertoire of HOFs exhibiting exceptional performance and industrial viability remains constrained.In this study,we proffer a novel methodology involving metal-nucleobase moieties with the paddle-wheel spatial conformation and multiple hydrogen bonding sites.These entities,formed through the integration of 2,6-diaminopurine and fluorinated anions(SiF_(6)^(2−),GeF_(6)^(2−),and NbOF_(5)^(2−)),can sel

关 键 词：氢键有机框架 极性位点 吸附分离 二氧化碳 甲烷提浓 

分 类 号：TE644[石油与天然气工程—油气加工工程] O647.3[理学—物理化学]