Preparation And Gas Separation Performance Studies Of Metal-Organic Framework Membrane

A single gas permeation setup using a time-lag method was constructedin this work, Cu-BTC metal-organic framework （MOF） and Cu-BTCmembrane supported on potassium hexatitanate were synthesized respectivelyby the method of in situ hydrothermal method. The characterizations andseparation performances for helium recovery were also studied in this thesis.As a new family of porous materials, MOFs which have the advantagesof super high porosity, large surface area, synthetic convenience and thevariability of pore size, were considered to be another important class ofnanomatierials. MOFs are attracting more and more attention nowadays, andhave been widely studied in the fields of gas storage, separation, sensors,catalysis, and drug release. On the other hand, promising results are expectedwhen MOFs membranes are used for separation according to the microporousnature and variability of pore structure of MOF materials.Cu-BTC, as a typical MOF material, has been widely studied in gasstorage and separation. Potassium hexatitanate （K₂Ti₆O₁3） with a tunnelstructure is capable of being a membrane substrate, considering its advantages including high thermal and chemical stability, high strength and stiffness, andhigh thermal insulating ability. In addition, this kind of support was found tobe more suitable for the growth of Cu²⁺-containing MOF membranes thanother traditional supports, such as porous alumina support. Therefore, Cu-BTCand potassium hexatitanate were chosen as a membrane material and supportrespectively in this work.An integrated Cu-BTC membrane was successfully prepared on the novelpotassium hexatitanate support for the first time by in situ hydrothermalgrowth. The permeation results of Cu-BTC membranes obtained in this workshow moderate separation selectivities of He over other small gas molecules,including CO2, N2, and CH4. Compared to other MOF membranes, theCu-BTC membrane exhibits higher ideal selectivity for He under the conditionof similar He permeance, while has higher He permeance with similar idealselectivity.