Preparation and characterization of thin film nanocomposite membrane for pervaporative dehydration of aqueous alcohol solutions

Thin film nanocomposite (TFN) polyamide membranes were synthesized via the interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) with nano NaX zeolite on the surface of the modified polyacrylonitrile (mPAN) membrane as support layer. The fabricated TFN membrane was used in the pervaporative separation of 90 wt.% aqueous solutions of ethanol and isobutanol at 25 °C. In addition, surface properties and surface morphology as well as hydrophilicity of the TFN membranes were examined by AFM, FE-SEM, ATR-FTIR and contact angle (CA) analysis, respectively. The results showed that the addition of nano NaX zeolite to the polyamide layer led to the improvement of the surface roughness and increase in the surface hydrophilicity which raised the water flux in the TFN membrane. Also, the pervaporation performance of the TFN membranes was strongly affected by the nano NaX zeolite concentration. In all the samples, the flux and separation factor of the TFN membrane became more than twice that of the TFC polyamide membrane. The permeation flux and separation factor of the aqueous ethanol solution enhanced by increasing the concentration of nano NaX zeolite, while the flux of isobutanol solution had a maximum at the zeolite concentration of 0.5 wt.%.

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► A nano zeolite/polyamide TFN membrane was synthesized for using in pervaporation.
► The zeolite content effect in PA layer on water/alcohol separation was investigated.
► The effect of alcohol size on separation factor and permeability was evaluated.
► Surface properties of TFN membrane were characterized by AFM, ATR and FESEM.