- Email: [email protected]
Knudsen diffusion in microporous carbon membranes
CALENDAR
Events Calendar 4–6 March 2003
18–20 March 2003
Water & Wastewater Europe
9th Aachen Membrane Colloquium
Nice, France Contact: Koula Karayianni PennWell Corp, PennWell House, Horseshoe Hill, Upshire, Essex EN9 3SR, UK Tel: +44 1992 656 631 Fax: +44 1992 656 704 Email: [email protected]
8–12 March 2003 Water Science and Technology Association Sixth Gulf Water Conference Riyadh, Saudi Arabia Contact: Professor Walid Abdulrahman Chairman of Scientific Committee, Water Science and Technology Association, PO Box 20018, Manama, Bahrain Tel: +973 826512 Fax: +973 826513 Email: scientific-committee@ wsta-gcc.org
Aachen, Germany Contact: Dipl.-Ing. Johannes Meier Institut für Verfahrenstechnik (IVT) der RWTH Aachen, Turmstraße 46, D-52056, Aachen, Germany Tel: +49 241 80 95428 Fax: +49 241 80 92252 Email: [email protected]
28–30 March 2003 7th International Water Technology Conference (IWTC-VII) Egypt Contact: Prof. Magdy Abou Rayan Conference Secretary General, Mansoura University, Faculty of Engineering, El-Mansoura 35516, Egypt Tel/Fax: +20 (3) 5920641 Email: [email protected] Web: www.maxpages.com/iwtcivgypt
7–11 April 2003 Water Berlin 2003
10–13 March 2003 Water China 2003 Guangzhou (Canton), PR China Contact: MEREBO Messe Marketing Hellbrookstrasse 86, 22305 Hamburg, Germany Tel: +49 40 6087 6926 Fax: +49 40 6087 6927 Email: [email protected] Web: www.merebo.de
Berlin Trade Fair and Exhibition Complex, Berlin, Germany Contact: Benjamin Sanders, Project Manager, Messe Berlin North America, 701 Kenmore Avenue, Suite 220, Fredericksburg, VA 22401, USA Tel: +1 540 372 3777 Fax: +1 540 372 1414 Email: [email protected] Web: www.wasser-berlin.com
Knudsen diffusion in microporous carbon membranes Measurements were done on a relatively wide pore carbon molecular sieve membrane (CMSM) by means of a range of probe molecules (He, H2, N2, CH4, CO2 and C5H12) at temperatures between 25°C and 500°C. At high temperatures, where adsorption effects are attenuated, the permeance of the carbon membrane to pure gases displayed the molecular weight and temperature dependence expected from Knudsen diffusion, even though the pore size distribution lies demonstrably below 0.55 nm. Using a concept of an effective diameter, the authors analyzed the temperature dependence of the probe molecules’ permeabilities and separated out the relative contribution of the different gas transport mechanisms in the pores of the carbon microporous membranes. Calculations of the total gas permeance from two different idealized membrane pore structures were made and compared with measured permeances. The comparison showed that an idealized pore structure, comprising larger and smaller diameter pore regions essentially connected in series, can reasonably explain the measurements. The estimate for the larger pore diameter was found by using the temperature dependence of n-pentane
Membrane Technology January 2003
9 April 2003
4th International Conference on Membrane Bioreactors (MBR 4) Cranfield, UK Contact: The Short Course Office, Cranfield University Tel: +44 1234 754176 Fax: +44 1234 751206 Email: [email protected] Web: www.cranfield.ac.uk/sims/water/ mbrcourse.htm
27 April–1 May 2003
Practical on Membrane Technology Texas, USA Contact: Mr Carl Vavra, Separation Sciences Group Food Protein R&D Center, 2476 TAMU, Olsen Boulevard, Cater-Mattil Hall, Texas A&M University, College Station, TX 77843-2476, USA Tel: +1 979 845 2758 Fax: +1 979 845 2744 Email: [email protected] Web: www.tamu.edu/separations
4–8 May 2003
Desalination and the Environment: Fresh Water for All St Julian’s, Malta Contact: Miriam Balaban European Desalination Society, Science and Technology Park of Abruzzo, Via Antica Arischia 1, 67100 L’Aquila, Italy Tel: +39 0862 3475 308 Fax: +39 0862 3475 213 Email: [email protected]
17–20 June 2003 American Filtration & Separations Society 16th Annual Conference and Exposition Reno, Nevada, USA Contact: Kathleen Hemming, Conference Coordinator, AFS Society, 252 N. Washington Street, Suite A, Falls Church, VA 22046, USA Tel: +1 703 538 1000 Fax: +1 703 538 6305 Email: [email protected]
7–11 September 2003 PERMEA 2003 Tatranské Matliare, Slovakia. Contact: Ing. Rudolf Kertész (Secretary and Registration) Department Chem. Biochem. Eng, Slovak University of Technology, Radliského 9, 81237 Bratislava, Slovakia Tel: +421 2 59325 265 Fax: +421 2 52496743 Email: [email protected]
17–18 September 2003 Nitrate and Phosphate Removal Short Course Cranfield, UK Contact: Short Course Office Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK Tel: +44 1234 754176 Fax: +44 1234 751206 Email: [email protected]
permeance, which showed behaviour approaching that to be expected for activated diffusion typical of sieving membranes. The larger diameter region of the pore system was estimated to be 0.58 nm and the smaller diameter region to be 0.43–0.48 nm. After correction for the contribution of Knudsen diffusion, the gases tested could be ranked according to the contribution of adsorption-mediated transport as follows: CO2 > CH4 > N2 > H2 > He based on the calculated net energies for pore transport. This is consistent with the ranking to be found for adsorption isotherms of these gases on activated glassy carbon. J. Gilron and A. Soffer: J. of Membrane Science 209(2) 339–352 (15 November 2002).
by pore blockage, with a cake then forming over the blocked areas of the membrane. This combined pore ‘blockage–cake filtration’ model is in good agreement with experimental data obtained during the constant flux filtration of bovine serum albumin through track-etched MF membranes. The total volume of the feed solution that can be filtered through the membrane before the transmembrane pressure exceeds some critical value increases with decreasing flux because of the reduction in the rate of cake growth at low flux. Model simulations were used to provide important insights into the design and operation of constant flux MF processes. C.-C. Ho and A.L. Zydney: J. of Membrane Science 209(2) 363–377 (15 November 2002).
Transmembrane pressure profiles during constant flux MF
Salt retention using multi-layer ceramic membranes
Many microfiltration (MF) systems are now run at constant filtrate flux to achieve improved performance. However, large increases in transmembrane pressure are often required to maintain the flux at a constant value because of membrane fouling. The authors have developed a new mathematical model to describe the change in transmembrane pressure during constant flux MF. Fouling is assumed to occur first
This paper reports the characterization of a multi-layer TiO2 membrane consisting of two mesoporous anatase inter-layers and a microporous anatase top-layer, prepared by a sol-gel procedure. A molecular weight cut-off (MWCO) in the range 500–600, and a permeability of 20 L h–1 m–2 bar–1 was demonstrated. In order to provide information about the membrane charge, a detailed study was made of
15
Events Calendar 4–6 March 2003
18–20 March 2003
Water & Wastewater Europe
9th Aachen Membrane Colloquium
Nice, France Contact: Koula Karayianni PennWell Corp, PennWell House, Horseshoe Hill, Upshire, Essex EN9 3SR, UK Tel: +44 1992 656 631 Fax: +44 1992 656 704 Email: [email protected]
8–12 March 2003 Water Science and Technology Association Sixth Gulf Water Conference Riyadh, Saudi Arabia Contact: Professor Walid Abdulrahman Chairman of Scientific Committee, Water Science and Technology Association, PO Box 20018, Manama, Bahrain Tel: +973 826512 Fax: +973 826513 Email: scientific-committee@ wsta-gcc.org
Aachen, Germany Contact: Dipl.-Ing. Johannes Meier Institut für Verfahrenstechnik (IVT) der RWTH Aachen, Turmstraße 46, D-52056, Aachen, Germany Tel: +49 241 80 95428 Fax: +49 241 80 92252 Email: [email protected]
28–30 March 2003 7th International Water Technology Conference (IWTC-VII) Egypt Contact: Prof. Magdy Abou Rayan Conference Secretary General, Mansoura University, Faculty of Engineering, El-Mansoura 35516, Egypt Tel/Fax: +20 (3) 5920641 Email: [email protected] Web: www.maxpages.com/iwtcivgypt
7–11 April 2003 Water Berlin 2003
10–13 March 2003 Water China 2003 Guangzhou (Canton), PR China Contact: MEREBO Messe Marketing Hellbrookstrasse 86, 22305 Hamburg, Germany Tel: +49 40 6087 6926 Fax: +49 40 6087 6927 Email: [email protected] Web: www.merebo.de
Berlin Trade Fair and Exhibition Complex, Berlin, Germany Contact: Benjamin Sanders, Project Manager, Messe Berlin North America, 701 Kenmore Avenue, Suite 220, Fredericksburg, VA 22401, USA Tel: +1 540 372 3777 Fax: +1 540 372 1414 Email: [email protected] Web: www.wasser-berlin.com
Knudsen diffusion in microporous carbon membranes Measurements were done on a relatively wide pore carbon molecular sieve membrane (CMSM) by means of a range of probe molecules (He, H2, N2, CH4, CO2 and C5H12) at temperatures between 25°C and 500°C. At high temperatures, where adsorption effects are attenuated, the permeance of the carbon membrane to pure gases displayed the molecular weight and temperature dependence expected from Knudsen diffusion, even though the pore size distribution lies demonstrably below 0.55 nm. Using a concept of an effective diameter, the authors analyzed the temperature dependence of the probe molecules’ permeabilities and separated out the relative contribution of the different gas transport mechanisms in the pores of the carbon microporous membranes. Calculations of the total gas permeance from two different idealized membrane pore structures were made and compared with measured permeances. The comparison showed that an idealized pore structure, comprising larger and smaller diameter pore regions essentially connected in series, can reasonably explain the measurements. The estimate for the larger pore diameter was found by using the temperature dependence of n-pentane
Membrane Technology January 2003
9 April 2003
4th International Conference on Membrane Bioreactors (MBR 4) Cranfield, UK Contact: The Short Course Office, Cranfield University Tel: +44 1234 754176 Fax: +44 1234 751206 Email: [email protected] Web: www.cranfield.ac.uk/sims/water/ mbrcourse.htm
27 April–1 May 2003
Practical on Membrane Technology Texas, USA Contact: Mr Carl Vavra, Separation Sciences Group Food Protein R&D Center, 2476 TAMU, Olsen Boulevard, Cater-Mattil Hall, Texas A&M University, College Station, TX 77843-2476, USA Tel: +1 979 845 2758 Fax: +1 979 845 2744 Email: [email protected] Web: www.tamu.edu/separations
4–8 May 2003
Desalination and the Environment: Fresh Water for All St Julian’s, Malta Contact: Miriam Balaban European Desalination Society, Science and Technology Park of Abruzzo, Via Antica Arischia 1, 67100 L’Aquila, Italy Tel: +39 0862 3475 308 Fax: +39 0862 3475 213 Email: [email protected]
17–20 June 2003 American Filtration & Separations Society 16th Annual Conference and Exposition Reno, Nevada, USA Contact: Kathleen Hemming, Conference Coordinator, AFS Society, 252 N. Washington Street, Suite A, Falls Church, VA 22046, USA Tel: +1 703 538 1000 Fax: +1 703 538 6305 Email: [email protected]
7–11 September 2003 PERMEA 2003 Tatranské Matliare, Slovakia. Contact: Ing. Rudolf Kertész (Secretary and Registration) Department Chem. Biochem. Eng, Slovak University of Technology, Radliského 9, 81237 Bratislava, Slovakia Tel: +421 2 59325 265 Fax: +421 2 52496743 Email: [email protected]
17–18 September 2003 Nitrate and Phosphate Removal Short Course Cranfield, UK Contact: Short Course Office Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK Tel: +44 1234 754176 Fax: +44 1234 751206 Email: [email protected]
permeance, which showed behaviour approaching that to be expected for activated diffusion typical of sieving membranes. The larger diameter region of the pore system was estimated to be 0.58 nm and the smaller diameter region to be 0.43–0.48 nm. After correction for the contribution of Knudsen diffusion, the gases tested could be ranked according to the contribution of adsorption-mediated transport as follows: CO2 > CH4 > N2 > H2 > He based on the calculated net energies for pore transport. This is consistent with the ranking to be found for adsorption isotherms of these gases on activated glassy carbon. J. Gilron and A. Soffer: J. of Membrane Science 209(2) 339–352 (15 November 2002).
by pore blockage, with a cake then forming over the blocked areas of the membrane. This combined pore ‘blockage–cake filtration’ model is in good agreement with experimental data obtained during the constant flux filtration of bovine serum albumin through track-etched MF membranes. The total volume of the feed solution that can be filtered through the membrane before the transmembrane pressure exceeds some critical value increases with decreasing flux because of the reduction in the rate of cake growth at low flux. Model simulations were used to provide important insights into the design and operation of constant flux MF processes. C.-C. Ho and A.L. Zydney: J. of Membrane Science 209(2) 363–377 (15 November 2002).
Transmembrane pressure profiles during constant flux MF
Salt retention using multi-layer ceramic membranes
Many microfiltration (MF) systems are now run at constant filtrate flux to achieve improved performance. However, large increases in transmembrane pressure are often required to maintain the flux at a constant value because of membrane fouling. The authors have developed a new mathematical model to describe the change in transmembrane pressure during constant flux MF. Fouling is assumed to occur first
This paper reports the characterization of a multi-layer TiO2 membrane consisting of two mesoporous anatase inter-layers and a microporous anatase top-layer, prepared by a sol-gel procedure. A molecular weight cut-off (MWCO) in the range 500–600, and a permeability of 20 L h–1 m–2 bar–1 was demonstrated. In order to provide information about the membrane charge, a detailed study was made of
15