The Research On Preparing PEA-MPA Block Copolymers And PEA-MPA-based Hybrid Membranes For CO₂/CH₄ Separation

The current research has focused on the development of efficient,green CO₂ separation technology to achieve the purification of methane.Membrane separation technology has been attracted more and more attention because of its advantages of high efficiency,low cost and so on.In CO₂ separation process,membrane materials play an important role in the separation performance of membrane separation process.Therefore,it has great significance to develop new and efficient membrane materials.In this paper,a series of PEA-MPA block copolymers were designed and synthesized based on the solubility and diffusivity mechanism.After that,PEA-MPA block copolymer was used as the optimum polymer matrix of the hybrid membrane and prepared PEA-MPA-based hybrid membranes were used for effective CO₂ separation.The details were summarized as follows:The design and preparation of PEA-MPA block copolymer membranes for efficient CO₂ separation:In order to obtain high CO₂ permeability and CO₂/CH₄ selectivity polymer membranes,a series of block copolymer membranes with improved solubility selectivity and diffusivity selectivity were designed by using polyetheramine?PEA?and methyl-containing polyamide?MPA?.PEA contained abundant ethylene oxide?EO?units which are beneficial to increase solubility selectivity in membranes.The bulky methyl?Me?substituent was introduced intoMPAbypolymerizingfromisophthaloyldichloride?IPC?,2,5-dimethyl-1,4-phenylenediamine?DPD?and 4,4'-bis?3-aminophenoxy?diphenylsulfone?BADS?to increase diffusivity selectivity in membranes.CO₂ separation performance of block copolymer membranes is improved by tailoring PEA/MPA mass ratio and BADS/DPD mole ratio.The result indicated that the membrane with PEA/MPA mass ratio of 6/4 and BADS/DPD mole ratio of 1/10showed the optimum CO₂ separation performance with CO₂ permeability of 629 Barrer,and CO₂/CH₄ selectivity of 23.The design and preparation of PEA-MPA/TETA-?-CD hybrid membranes for efficient CO₂ separation:The PEA-MPA was used as the polymer matrix,and TETA modified?-CD was used as the filler.On the one hand,the amine groups containing on the surface of TETA-?-CD can react with CO₂,introducing CO₂ transport sites.On the other hand,the cavity of?-CD can increase the gases diffusivity in the membranes.The optimum separation performance was achieved at the TETA-?-CD content of 7 wt%with selectivity of 41 for CO₂/CH₄ and a CO₂permeability of 920 Barrer.The design and preparation of PEA-MPA/PEI-ATP hybrid membranes for efficient CO₂ separation:The PEA-MPA was used as the polymer matrix,and PEI modified ATP was used as the filler.On the one hand,the amine groups containing on the surface and inside channel of PEI-ATP can react with CO₂,intensifying CO₂ transport sites.On the other hand,the cavity of ATP can increase the FFV of the membranes,increasing the gases diffusivity in the membranes.The optimum separation performance was achieved at the PEI-ATP content of 5 wt%with selectivity of 49 for CO₂/CH₄ and a CO₂ permeability of 838 Barrer.