Effects of Shear Rate on Morphology and Gas Separation Performance as Asymetric Polysulfone Membranes

https://doi.org/10.22146/ajche.50805

Ahmad Fauzi Ismail(1*), Lai Ping Yean(2)

(1) Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru Tel: 07-5505392, Fax: 07-5581463
(2) Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru Tel: 07-5505392, Fax: 07-5581463
(*) Corresponding Author

Abstract


Asymmetric polysulfone flat sheet membranes have been produced by a dry/wet casting technique. The membranes were produced at different shear rate. Gas permeation properties were examined using pure hydrogen and nitrogen as test gases. Infrared dichroism was detected in all samples, the extent being greater in the high shear membranes. This suggests that the polymer molecules become aligned under high shear. Gas separation tests showed that the higher shear membranes exhibited greater selectivity (H!Nz)' Some of the membrane selectivities even surpass the intrinsic selectivity of the membrane polymer. Increasing shear rate during casting had decreased skin layer thickness and thus increased pressure-normalized flux. High-shear casting also enhances the molecular orientation in skin layer and, in turn, heighten selectivity of membrane. Therefore, correlation of rheological aspects with primary phase inversion parameters provides a potential platform to develop high performance asymmetric polysulfone membranes for gas separation.
Key words: asymmetric membranes, gas separation, rheology, molecular orientation, super-selective, polysulfone

Keywords


asymmetricmembranes, gasseparation, rheology,molecular orientation, super-selective, polysulfone

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References

  1. Pinnau, I., Koros, W. J. A Qualitative Skin Layer Formation Mechanism for Membranes Made by Dry/Wet Phase inversion, J. Polymer. Sci.: Part B: Polym. Phy.1993, Vol. 31, pp 419-427
  2. Termonia, Y Fundamentals of Polymer Coagulation, J. Polymer. Sci.: Part B: Polym. Phy. 1995, Vol. 33, pp 279-288
  3. van't Hof, J. A., Reuvers, A. J., Boom, R. M., Rolevink, H. H. M., Smolders, C. A. Preparation of Asymmetric Gas Separation Membranes with High Selectivity by a Dual- Bath Coagulation Method, J. Membr. Sci. 1992, Vol. 70, pp 17-30
  4. Pesek, S. C. and Koros, W. J. Aqueous Quenched Asymmetric Polysulfone Membranes prepared by Dry/Wet Phase Separation, J. Membr. Sci. 1993, Vol. 81, pp 71-88
  5. Sharpe, I. D., Ismail, A. F.,Shilton, S. J. A Study of Extrusion Shear and Forced Convection Residence time in the Spinning of Polysulfone Hollow fiberMembranes for Gas Separation, Sep. Pur. Technol. 1999, Vol. 17, pp 101-109
  6. Ismail, A. F.,Dunkin, I. R., Gallivan, S. L., Shilton, S. J. Production of Super Selective Polysulfone Hollow Fiber Membranes for Gas Separation. Polymer.1999, Vol. 40, pp 6499~6506.
  7. Paul, D. R. and Yampol' skii, Y P., "Polymeric Gas Separation Membranes", CRC Press Inc., Boca Raton (1994) p. 1-15.
  8. Bungay, P. M., Lonsdale, H. K. and De Pinho, M. N., "Synthetic Membranes: Science, Engineering and Applications", D. Riedel Pub., Dordrecht (1986) p. 1-38.
  9. Wang, I. F. and Minhas, B. S., 1991, U.S. Pat. 5,067,970.
  10. Ismail,A. F.,Shilton, S. J., Dunkin, I.R. and Gallivan, S. L., Direct Measurement of Rheologically Induced Molecular Orientation in Gas Separation Hollow Fiber Membranes and Effects on Selectivity,J. Membr. Sci., 1997, Vol. 126 pp 133-137.
  11. Shilton, S.J., Bell,G. and Ferguson,J., The Rheology of Fiber Spinning and the Properties of Hollow-Fiber Membranes for Gas Separation, Polymer, 1994, Vol. 35 pp 5327-5335.
  12. Shilton, S. J., Ismail, A. F., Gough, P.J., Dunkin, I. R. and Gallivan, S. L., Molecular Orientation and the Performance of Synthetic Polymeric Membranes for Gas Separation, Polymer, 1997, Vol. 38 pp 2215-2220.
  13. Chung, T.S., Un, W.H. and Vora, R. H., The Effect of Shear Rates on Gas Separation Performance of 6FDA-Durene Polyimide Hollow Fibers, J. Membr. Sci., 2000, Vol. 167 pp 55-66.
  14. Sharpe, I. D., Ismail, A. F.and Shilton, S. J., A Study of Extrusion Shear and Forced Convection Residence Time in the Spinning of Polysulfone Hollow Fiber Membranes for Gas Separation, Sep. & Purif Tech., 1999, Vol. 17 pp 101-109.
  15. Wang, R. and Chung, T. S., Determination of Pore Sizes and Surface Porosity and the Effect of Shear Stress Within a Spinneret on Asymmetric Hollow Fiber Membranes, J. Membr. Sci., 2001, Vol. 188 pp 29-37.
  16. Pinnau, I. and Koras, W. J., Relationship between Substructure Resistance and Gas Separation Properties of Defect-Free Integrally Skinned Asymmetric Membranes, Ind. Eng. Chem. Res., 1991, Vol. 30 pp 1837-1840.
  17. Ismail,A. F.,Yean, L. P. A review on the development of defect-free and ultrathin-skinned asymmetric membranes for gas separation through manipulation of phase inversion and rheological factors, accepted for publication in Journal of Applied Polymer Science, 2002.



DOI: https://doi.org/10.22146/ajche.50805

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ASEAN Journal of Chemical Engineering  (print ISSN 1655-4418; online ISSN 2655-5409) is published by Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada.