Porous Organic Polymers-based Mixed Matrix Membrane And Gas Separation Performance Optimization

Membrane-based separation technology with great features of low-energy consumption,operational simplicity,and low environmental footprint,has caused more attention in chemical separation process.Membrane material is an important content of membrane separation technology,which is the key to achieve high separation performance of membrane.Polymer membranes with a low cost and easy processing were currently widely used materials for membrane separation.However,the Trade-off effect（between permeability and selectivity）of polymeric membranes limits its separation performance.Although inorganic membranes（such as MFI membrane,zeolite membranes）can effectively achieve high permeability and high selectivity,it is brittle.Mixed-matrix membranes can efficiently combine both the merit of the inorganic filler and polymer matrix.Porous organic polymers as an amorphous porous organic polymer material exhibit an excellent separation performance for gas purify.Pelyther block amide 1657（Pebax 1657）is a commercial membrane material with the advantages of low price and easy availability.In this paper,the high-performance mixed matrix membranes were constructed based on Pebax 1657 polymer matrix and porous organic polymers via a simple solvent evaporation method and their separation performance were investigated.The main contents are shown below:Synthesis of POPs.POPs materials with high specific surface area,good dispersion and stable structure were prepared by azo reaction.The obtained POPs have an excellent thermal stability and exhibit an excellent adsorption selectivity for CO₂/N₂.To provide molecular-sieving channels for efficient CO₂ separation,we combined POPs with PGO via bonding effect to establish an ordered stack of dual-channel PGO sieving membranes for gas separation.An effective molecular sieve separation channel was constructed by using quinone bond formed by phenol-OH on POPs and the carboxyl group on PGO.The azo groups（–N=N–）of POPs can reject N₂,thus improving the selectivity.The obtained hybrid membrane exhibit 232Barrer of CO₂ permeability and 81 of CO₂/N₂ ideal selectivity,surpassing the 2008Robeson’s upper bound.The mixed matrix membrane for CO₂ capture is prepared via incorporating porous organic polymer nanosheets（POPs）and polyethylene glycol 400（PEG 400）into Pebax 1657.The hydrogen bond between phenolic-OH of POPs and Pebax 1657or PEG 400,which is binomial for POPs dispersion.The PEG 400 with numerous ethylene oxide（EO）units,resulting in the CO₂ permeability and CO₂/N₂ selectivity of obtained hybrid membranes have an improvement.The phenolic hydroxyl groups and azo bonds in POPs have the characteristic of“CO₂-phlic,N₂-phobic”,which can improve the selectivity of CO₂/N₂.The obtained hybrid membrane CO₂ permeability reaches 392 Barrer and the ideal selectivity of CO₂/N₂ is 112,surpassing the Robeson upper bound（2008）...