Fabrication Of PIM-1/PDMS Hybrid Membrane And Its Pervaporation Performance

With the rapid development of economy,energy crisis is becoming more and more serious in the world.As one of the most valuable biofuels,the exploitation and application of biobutanol provides an alternative solution to the crisis.Usually,the production of butanol is strictly limited by product inhibition by conventional A-B-E?acetone-butanol-ethanol?fermentation,resulting in low yield and low concentration?0.5-1 wt%?.Due to the normal boiling point of n-butanol is higher than that of water,n-butanol and water tends to form an azeotrope,which makes the separation processes of n-butanol from water using conventional technology such as extraction and distillation more energy intensive.Comparatively,membrane separation techniques like pervaporation have many advantages including low energy consumption,high separation factor,simple operation and so on,therefore are very promising to be applied for the efficient recovery of n-butanol from dilute aqueous solutions.Membrane material plays a critical role in organophilic pervaporation.To prepare qualified organophilic pervaporation membrane which can selectively separate organic solvents from water,macromolecular polymers with different functionality are often utilized.The commonly used materials for organophilic pervaporation membranes are the hydrophobic organic polymers.Among them,PDMS is often considered as a benchmark material owing to the advantages of low surface tension,good thermostability and commercial availability.Normally,due to the trade-off between permeability and selectivity,the pristine PDMS membrane would be difficult to obtain the excellent PV performance for industrial n-butanol recovery.To solve this problem,MMMs combined with inorganic filler and polymer matrix was proposed for the improvement of pervaporation performance.Although these MMMs obtained relatively high separation factor,the permeation flux are still limited.Moreover,there are other challenges such as chain rigidity,weak interfacial compatibility,aggregation of nanoparticles and low structural stability.Therefore,the exploration of high-quality MMMs with good affinity between filler and organic polymers is of paramount importance.As a new kind of microporous organic polymer,the polymers of intrinsic microporosity?PIMs?materials have unique characteristics such as high fractional free volume,large surface area,outstandingly physical and chemical stability.Moreover,due to the organophilicity,PIM-1 has good compatibility with traditional polymer matrix.Therefore,blending PIM-1 with traditional polymer matrix can minimize these obstacles encountered with the inorganic filler,and improve membrane performance for separation.A PIM-1/polydimethylsiloxane?PDMS?hybrid pervaporation membrane was prepared by combining rigid PIM-1 and flexible PDMS.The properties of the PIM-1/PDMS membrane were characterized and evaluated using various techniques including FTIR,SEM,EDS,NMR,GPC,contact angle centrifugation,N₂ absorption/desorption,pervaporation measurements,and swelling tests.Compared with the pure PDMS membrane,the prepared PIM-1/PDMS pervaporation membrane exhibited excellent permeation flux of 1425.3 g/?m²·h?and separation factor of 30.7 in the low concentration n-butanol/water system separation.In addition,the film exhibits excellent stability and integrity even in a long-term continuous operation of 240 hours,showing great industrial application potential.In addition,PIM-1 has strong solvent resistance and has great application prospects in the production of stable pervaporation membranes for industrial recovery of n-butanol.