Preparation Of Pebax/Nanoporous Materials Mixed Matrix Membrane And Application For Gas Separation

Compared to traditional separation techniques such as adsorption,gas membrane separation and purification technology has the advantages of environmental friendly,ease of operation,and high efficiency.To develop an efficient CO₂ separation membrane materials is the key of gas membrane separation research.The mixed matrix membrane?MMMs?can combine the advantages of the organic polymers and inorganic materials to obtain a membrane with excellent CO₂ separation performance.In this paper,polyether-polyamide block copolymers?Pebax 1657,Pebax?was used as polymer matrix to prepare high-performance MMMs,and different types gas transfer channels were built by using different appearances inorganic fillers.and the MMMs was used for the separation of the CO₂/CH₄ mixed gas.The main research contents and results of this paper are as follows:Preparation of Pebax/HKUST-1 MMMs and application for CO₂ Separation:One-dimensional tubular HKUST-1 was synthesized in Pebax solution by in-situ synthesis method to prepare Pebax/HKUST-1 MMMs,and a tubular CO₂ delivery channel was constructed within the membrane.On the one hand,the tubular channels can provide CO₂ fast transfer channels which would increase the CO₂ permeability,on another hand,free Cu²⁺sites in HKUST-1 increase CO₂solubility to enhance the CO₂/CH₄ selectivity.When the HKUST-1 loading was 4 wt%,the CO₂permeance and CO₂/CH₄ selectivity of the Pebax/HKUST-1 MMMs were 431.5 Barrer and 47.5,respectively,which were increased by 72.6%and 58.3%respectively compared with the Pebax membrane.Preparation of Pebax/MOF-2ns MMMs and application for CO₂ Separation:Two-dimensional super-lamellar MOF-2 nanosheet was used as fillers to prepare Pebax/MOF-2ns MMMs and vertical CO₂ transfer channels and gas selective barriers was constructed within the membrane.The microporous structure of MOF-2 nanosheets provides a path for the rapid transfer of CO₂ and increase the CO₂ permeability.The large aspect ratio of MOF-2 nanosheets as a selective barrier increase the selectivity of CO₂/CH₄.When the loading was 8 wt%,the CO₂ permeability and CO₂/CH₄ selectivity of the Pebax/MOF-2ns MMMs were 502.3 Barrer and 57,respectively,which was increased by 100.9%and 90.0%compared with the Pebax membrane.Preparation of Pebax-CNPs MMMs and application for CO₂ Separation:Three-dimensional hierarchical pore"sea urchin"-like porous nanocarbons?CNPs?were used as fillers to prepare Pebax-CNPs MMMs,and different pore type CO₂ transfer channels was built in the membrane.A large number of mesopores of CNPs can provide fast channels for the rapid and large-scale transfer of CO₂,and increase the permeability of CO₂.On the other hand,micropores can play a role of molecular sieve to improve CO₂/CH₄ selectivity.When the loading amount was 8 wt%,the CO₂ permeability and CO₂/CH₄ selectivity of Pebax-CNPs-8 were 510.1 Barrer and 56.8,respectively,which were respectively increased by 104.0%and 89.3%compared with Pebax membrane.