Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.

Membrane Technology and Applications

Correlation of separation factor versus permeability for polymeric membranes

The solution-diffusion model: a review

Principles and potential of the anaerobic digestion of waste-activated sludge

This article reviews the progress made in CO2 separation and capture research and engineering. Various technologies, such as absorption, adsorption, and membrane separation, are thoroughly discussed. New concepts such as chemical-looping combustion and hydrate-based separation are also introduced briefly. Future directions are suggested. Sequestration methods, such as forestation, ocean fertilization and mineral carbonation techniques are also covered. Underground injection and direct ocean dump are not covered.

Progress in carbon dioxide separation and capture: a review.

Polymers for gas separations: the next decade

Permeability coefficients P for He, O2, N2, CO2 CH4, C2H4, C2H6, and C3H8 in 12 different silicone polymer membranes were determined at 35.0°C and pressures up to 9 atm. Values of P for CO2, CH4, and C3H8 were also determined at 10.0 and 55.0°C. In addition, mean diffusion coefficients D and solubility coefficients S were obtained for CO2, CH4, and C3H8 in 6 silicone polymers at 10.0, 35.0, and 55.0°C. Substitution of increasingly bulkier functional groups in the side and backbone chains of silicone polymers results in a significant decrease in P for a given penetrant gas. This is due mainly to a decrease in D, whereas S decreases to a much lesser extent. Backbone substitutions appear to have a somewhat lesser effect in depressing P than equivalent side-chain substitutions. The selectivity of a silicone membrane for a gas A relative to a gas B, i.e., the permeability ratio P(A)/P(B), may increase or decrease as a result of such substitutions, but only if the substituted groups are sufficiently bulky. The selectivity of the more highly permeable silicone membranes is controlled by the ratio S(A)/S(B), whereas the selectivity of the less permeable membranes depends on both the ratios D(A)/D(B) and S(A)/S(B). The permeability as well as the selectivity of one silicone membrane toward CO2 were significantly enhanced by the substitution of a fluorine-containing side group that increased the solubility of CO2 in that polymer.

Structure-permeability relationships in silicone polymers

Diffusion coefficients of He, O2, N2, CO2, and CH4 at 300 K in four silicone polymers, namely, poly(dimethylsiloxane) (PDMS), poly(propylmethylsiloxane), poly((trifluoropropyl)methylsiloxane), and poly(phenylmethylsiloxane), have been estimated by molecular dynamics (MD) simulations. The estimated diffusion coefficients decrease with increasing size of the polymer side chains and of the penetrant molecules, as was also found experimentally. The estimated diffusion coefficient for He in PDMS is consistent with its experimental value. The values of the estimated diffusion coefficients for the other gas/silicone systems considered in this study are within ± 40−60% of the corresponding experimental values. The MD simulations revealed two types of motions of the penetrant molecules:  (1) “jumps” from one cavity in a silicone matrix to another, and (2) “oscillating motions” inside cavities. The lengths of the jumps are of the order of 8−15 A, whereas the oscillating motions are of the order of ≤5 A. The total t...

Diffusion of Gases in Silicone Polymers: Molecular Dynamics Simulations

Etude de la permeabilite vis-a-vis de CH 4 , N 2 , O 2 , H 2 et CO 2 de 9 membranes polyimide derivees de l'anhydride pyromellioique et du dianhydride d'un diacide propane bis-benzoique. Discussion des facteurs structuraux (mobilite segmentaire, distance interchaine, formation de complexes de transfert de charge) pouvant expliquer les differences de permeabilite

S.A. Stern

Papers

Polymers for gas separations: the next decade

Structure-permeability relationships in silicone polymers

Diffusion of Gases in Silicone Polymers: Molecular Dynamics Simulations

Structure/permeability relationships of polyimide membranes. Applications to the separation of gas mixtures

Hybrid processes for the removal of acid gases from natural gas