Gas transport properties of interfacially polymerized polyamide composite membranes under different pre-treatments and temperatures

• Published in: Journal of membrane science Vol. 449; pp. 109 - 118
• Main Authors: Albo, Jonathan, Wang, Jinhui, Tsuru, Toshinori
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2014; Elsevier
• Subjects: ambient temperature; Applied sciences; asymmetric membranes; Chemical engineering; Drying; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; freeze drying; Gas separation; Gas transport; Membrane pre-treatments; Membrane separation (reverse osmosis, dialysis...); Membranes; ovens; Polyamide; Polyamide resins; polyamides; Polymer industry, paints, wood; Polymerization; Reluctance; Reverse osmosis; RO membranes; solvents; Technology of polymers; Temperature influence; Polyamide; Gas separation; Membrane pre-treatments; Temperature influence; RO membranes; Ethylene terephthalate polymer; Freeze drying; Transport properties; Nylon; Sulfone polymer; Physical dressing; Aromatic polymer; Temperature effect; Washing; Immersion; Experimental study; Water permeability; Gas permeability; Selective permeability; Membrane; Reverse osmosis; Comparative study
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2013.08.026

Thin-film composite reverse osmosis membranes were dried under different membrane pre-treatment procedures and evaluated at increased temperatures by gas separation tests. The obtained permeance and selectivity values indicated the presence of highly-permeable regions in the dry samples of the commercial membranes. Treatment with ethanol–hexane in a solvent exchange process, as well as membrane immersion in t-butanol followed by freeze drying, increased the gas permeance by a factor of 1.8 to 9, and from 1.6 to 3.2, respectively, by comparison with room temperature and oven drying. Nevertheless, a Knudsen-diffusion transport mechanism was dominant after both pre-treatments. The permeation temperature remarkably influenced gas selectivity and permeance, and a maximum He/N2 selectivity occurred at 150°C with considerable high permeance results, which may suggest the use of polyamide membranes as alternative materials for high-temperature separation processes. The temperature-induced changes in the polymer structure and in the transport of compounds can be explained by Knudsen and activated diffusion mechanisms throughout a highly-permeable regions and a dense polyamide matrix, respectively. [Display omitted] •Polyamide thin-film composite RO membranes were evaluated by gas separation tests.•Gas permeance evidenced layer alteration after different membrane pre-treatments.•Gas transport was explained by Knudsen and activated diffusion mechanism.•The inhomogeneous polyamide layer consists of a dense and high permeable region.•Polyamide membranes show promises as high-temperature gas separation materials.