i Blume - Academia.edu (original) (raw)
Papers by i Blume
Makromolekulare Chemie. Macromolecular Symposia, 1991
Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon... more Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon dioxide through a variety of polyimides based on a hexafluorotetracarboxylic acid unit (6FDA) were investigated. Vapor diffusion through PDMS films strongly depends on the concentration of the penenant molecules in the network. For chloroform, increasing diffusivity at lower upstream activities occurs due to network plasticization, while a decreasing diffusion coefficient at larger concentration is supposed to stem from penetrant molecule clustering. The diffusion of carbon dioxide in 6FDA-based polyimides was modelled on a molecular basis. An exponential relation was found between Ac and the diffusion coefficient and the permeability, respectively. This relation hoks also for on-chain modifications.
Journal of Membrane Science, 1988
ABSTRACT Composite gas separation membranes generally consist of a selective, ultrathin top layer... more ABSTRACT Composite gas separation membranes generally consist of a selective, ultrathin top layer backed by a nonselective porous support. The top layer performs the separation and the support provides mechanical strength. A composite membrane will possess a selectivity close to the intrinsic selectivity of the top layer only if most of the permeation resistance lies within this top layer. To make high flux composite membranes, it is necessary to minimize the thickness of the selective layer. This, in turn, means the porous support must be very permeable. A simple model shows that the minimum thickness of a defect-free selective layer in a composite membrane having the intrinsic selectivity of the permselective layer is limited by the resistance of the porous support membrane. The model is supported by experimental gas and vapor permeation data for polysulfone-silicone rubber composites.
Journal of Membrane Science, 1990
The ability of thin composite membranes to separate dissolved organic solvents from water by perv... more The ability of thin composite membranes to separate dissolved organic solvents from water by pervaporation has been examined. The separation performance of a pervaporation process was considered as a combination of an evaporation step and a diffusion step. For the experimental work, poly (dimethylsiloxane) and polyolefin composite membranes were incorporated into O.l-0.3 m2, 2-inch diameter laboratory spiral-wound test modules. Typical fluxes were in the range 0.2-1.5 L/m2-h, depending on the operating conditions and the feed solution. The membranes used in this work were non-selective for polar solvents such as ethanol (a,,,< 1) so that the overall enrichment of polar solvents in the permeate was typically 5-10 fold. With non-polar solvents such as ethyl acetate, chloroform and 1,1,2-trichloroethane, where the membrane selectivity, amem, is greater than I, organic enrichment in the permeate of 50-400 fold was obtained. Pervaporation therefore appears to be an economically viable method of removing non-polar solvents from dilute aqueous streams. Preliminary calculations show plant capital costs in the range 2−5/galoffeedwaterperdayandoperatingcostsof2-5/gal of feed water per day and operating costs of 2−5/galoffeedwaterperdayandoperatingcostsof2-lO/l,OOO gal of feed water treated.
Makromolekulare Chemie. Macromolecular Symposia
Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon... more Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon dioxide through a variety of polyimides based on a hexafluorotetracarboxylic acid unit (6FDA) were investigated. Vapor diffusion through PDMS films strongly depends on the concentration of the penetrant molecules in the network. For chloroform, increasing diffusivity at lower upstream activities occurs due to network plasticization, while a decreasing diffusion coefficient at larger concentration is supposed to stem from penetrant molecule clustering. The diffusion of carbon dioxide in 6FDA-based polyimides was modelled on a molecular basis. An exponential relation was found between Δcp and the diffusion coefficient and the permeability, respectively. This relation holds also for on-chain modifications.
This patent describes a composite separation membrane comprising a two-layer composite of a suppo... more This patent describes a composite separation membrane comprising a two-layer composite of a support membrane layer and a permselective membrane layer. It comprises providing a support membrane layer characterized by permeation rates P{sub 1(A)}/lâ respectively of components A and B of a fluid mixture, wherein lâ is the thickness of the support membrane layer and P{sub 1(A)} and P{sub 1(B)} are the permeabilities to components A and B; providing a permselective material characterized by permeabilities P{sub 2(A)} and P{sub 2(B)} respectively to the components A and B, and by intrinsic selectivity α; determining an appropriate selectivity α{sub A/B} for the composite separation membrane for component A over component B; determining a thickness lâ for the permselective membrane layer, coating the support membrane layer with the permselective material to create a permselective membrane layer of thickness lâ.
This paper discusses a membrane for gas separation or pervaporation. The membrane is a composite ... more This paper discusses a membrane for gas separation or pervaporation. The membrane is a composite of a microporous support membrane and an ultrathin permselective membrane, the permselective membrane being made from a polyamide-polyether block copolymer. The membrane is particularly useful in separating polar gases from non-polar gases.
Journal of Membrane Science, 1988
Composite gas separation membranes generally consist of a selective, ultrathin top layer backed b... more Composite gas separation membranes generally consist of a selective, ultrathin top layer backed by a nonselective porous support. The top layer performs the separation and the support provides mechanical strength. A composite membrane will possess a selectivity close to the intrinsic selectivity of the top layer only if most of the permeation resistance lies within this top layer. To make high flux composite membranes, it is necessary to minimize the thickness of the selective layer. This, in turn, means the porous support must be very permeable. A simple model shows that the minimum thickness of a defect-free selective layer in a composite membrane having the intrinsic selectivity of the permselective layer is limited by the resistance of the porous support membrane. The model is supported by experimental gas and vapor permeation data for polysulfone-silicone rubber composites.
Sorption and permeation of several organic vapours in poly(dimethylsiloxane) were investigated. S... more Sorption and permeation of several organic vapours in poly(dimethylsiloxane) were investigated. Solubility and permeability coefficients measured show a strong dependence of the applied vapour activity typical for these systems, contrary to the behaviour of permanent gases. However, as irregularities in the series of chloromethanes show, highest sorption does not necessarily lead to the highest permeability value. A possible explanation of this effect can be found in the concentration dependent diffusion behaviour of poly(dimethylsiloxane) toward these organic vapours. Thus, from the kinetics of solvent uptake, i.e. the sorption isotherms over time, the diffusion coefficients, which were corrected for swelling and thermodynamic activity of the vapour, were calculated for the different vapour activities.
Makromolekulare Chemie. Macromolecular Symposia, 1991
Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon... more Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon dioxide through a variety of polyimides based on a hexafluorotetracarboxylic acid unit (6FDA) were investigated. Vapor diffusion through PDMS films strongly depends on the concentration of the penenant molecules in the network. For chloroform, increasing diffusivity at lower upstream activities occurs due to network plasticization, while a decreasing diffusion coefficient at larger concentration is supposed to stem from penetrant molecule clustering. The diffusion of carbon dioxide in 6FDA-based polyimides was modelled on a molecular basis. An exponential relation was found between Ac and the diffusion coefficient and the permeability, respectively. This relation hoks also for on-chain modifications.
Journal of Membrane Science, 1988
ABSTRACT Composite gas separation membranes generally consist of a selective, ultrathin top layer... more ABSTRACT Composite gas separation membranes generally consist of a selective, ultrathin top layer backed by a nonselective porous support. The top layer performs the separation and the support provides mechanical strength. A composite membrane will possess a selectivity close to the intrinsic selectivity of the top layer only if most of the permeation resistance lies within this top layer. To make high flux composite membranes, it is necessary to minimize the thickness of the selective layer. This, in turn, means the porous support must be very permeable. A simple model shows that the minimum thickness of a defect-free selective layer in a composite membrane having the intrinsic selectivity of the permselective layer is limited by the resistance of the porous support membrane. The model is supported by experimental gas and vapor permeation data for polysulfone-silicone rubber composites.
Journal of Membrane Science, 1990
The ability of thin composite membranes to separate dissolved organic solvents from water by perv... more The ability of thin composite membranes to separate dissolved organic solvents from water by pervaporation has been examined. The separation performance of a pervaporation process was considered as a combination of an evaporation step and a diffusion step. For the experimental work, poly (dimethylsiloxane) and polyolefin composite membranes were incorporated into O.l-0.3 m2, 2-inch diameter laboratory spiral-wound test modules. Typical fluxes were in the range 0.2-1.5 L/m2-h, depending on the operating conditions and the feed solution. The membranes used in this work were non-selective for polar solvents such as ethanol (a,,,< 1) so that the overall enrichment of polar solvents in the permeate was typically 5-10 fold. With non-polar solvents such as ethyl acetate, chloroform and 1,1,2-trichloroethane, where the membrane selectivity, amem, is greater than I, organic enrichment in the permeate of 50-400 fold was obtained. Pervaporation therefore appears to be an economically viable method of removing non-polar solvents from dilute aqueous streams. Preliminary calculations show plant capital costs in the range 2−5/galoffeedwaterperdayandoperatingcostsof2-5/gal of feed water per day and operating costs of 2−5/galoffeedwaterperdayandoperatingcostsof2-lO/l,OOO gal of feed water treated.
Makromolekulare Chemie. Macromolecular Symposia
Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon... more Mass transport of a number of organic vapors through polydimethylsiloxane films (PDMS) and carbon dioxide through a variety of polyimides based on a hexafluorotetracarboxylic acid unit (6FDA) were investigated. Vapor diffusion through PDMS films strongly depends on the concentration of the penetrant molecules in the network. For chloroform, increasing diffusivity at lower upstream activities occurs due to network plasticization, while a decreasing diffusion coefficient at larger concentration is supposed to stem from penetrant molecule clustering. The diffusion of carbon dioxide in 6FDA-based polyimides was modelled on a molecular basis. An exponential relation was found between Δcp and the diffusion coefficient and the permeability, respectively. This relation holds also for on-chain modifications.
This patent describes a composite separation membrane comprising a two-layer composite of a suppo... more This patent describes a composite separation membrane comprising a two-layer composite of a support membrane layer and a permselective membrane layer. It comprises providing a support membrane layer characterized by permeation rates P{sub 1(A)}/lâ respectively of components A and B of a fluid mixture, wherein lâ is the thickness of the support membrane layer and P{sub 1(A)} and P{sub 1(B)} are the permeabilities to components A and B; providing a permselective material characterized by permeabilities P{sub 2(A)} and P{sub 2(B)} respectively to the components A and B, and by intrinsic selectivity α; determining an appropriate selectivity α{sub A/B} for the composite separation membrane for component A over component B; determining a thickness lâ for the permselective membrane layer, coating the support membrane layer with the permselective material to create a permselective membrane layer of thickness lâ.
This paper discusses a membrane for gas separation or pervaporation. The membrane is a composite ... more This paper discusses a membrane for gas separation or pervaporation. The membrane is a composite of a microporous support membrane and an ultrathin permselective membrane, the permselective membrane being made from a polyamide-polyether block copolymer. The membrane is particularly useful in separating polar gases from non-polar gases.
Journal of Membrane Science, 1988
Composite gas separation membranes generally consist of a selective, ultrathin top layer backed b... more Composite gas separation membranes generally consist of a selective, ultrathin top layer backed by a nonselective porous support. The top layer performs the separation and the support provides mechanical strength. A composite membrane will possess a selectivity close to the intrinsic selectivity of the top layer only if most of the permeation resistance lies within this top layer. To make high flux composite membranes, it is necessary to minimize the thickness of the selective layer. This, in turn, means the porous support must be very permeable. A simple model shows that the minimum thickness of a defect-free selective layer in a composite membrane having the intrinsic selectivity of the permselective layer is limited by the resistance of the porous support membrane. The model is supported by experimental gas and vapor permeation data for polysulfone-silicone rubber composites.
Sorption and permeation of several organic vapours in poly(dimethylsiloxane) were investigated. S... more Sorption and permeation of several organic vapours in poly(dimethylsiloxane) were investigated. Solubility and permeability coefficients measured show a strong dependence of the applied vapour activity typical for these systems, contrary to the behaviour of permanent gases. However, as irregularities in the series of chloromethanes show, highest sorption does not necessarily lead to the highest permeability value. A possible explanation of this effect can be found in the concentration dependent diffusion behaviour of poly(dimethylsiloxane) toward these organic vapours. Thus, from the kinetics of solvent uptake, i.e. the sorption isotherms over time, the diffusion coefficients, which were corrected for swelling and thermodynamic activity of the vapour, were calculated for the different vapour activities.