Differential thermo-osmotic permeability in water–cellophane systems

Fernández‐Pineda, C.; Vázquez‐González, Margarita

doi:10.1039/f19888400647

Cited by 10 publications

(9 citation statements)

References 1 publication

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“…(4) has been carried out considering the use of both nonporous and porous membranes. In the first case, measurements of the thermoosomosis of water have been carried out with cellophane membrane 6OOP with a thickness of (56.4 2 1.8) X m subjected to the same treatment and with the experimental device described in a previous work (6). The measurements have been carried out at various average temperatures and under various temperature differences, and the values of Bexp were obtained at the different stirring rates presented in Table 4.…”

Section: Analysis Of Resultsmentioning

confidence: 99%

Parameters that may Influence the Correction Factor in Membranes Subjected to Thermal Gradients

Vázquez‐González

Serrano

1992

Separation Science and Technology

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Various treatments are generalized through which the phenomenon of polarization of temperatures can be approached, and an expression for its correction factor which gives an account of the parameters that may influence its value is achieved. An equation is found which enables the determination of some experimental parameters which are difficult to measure through direct methods. The equation mentioned above has been analyzed for both porous and nonporous membranes. In the case of porous membranes, this equation is found useful as long as the thermoosmotic coefficient employed is the one obtained after having taken into account the mechanism which produces the mass transfer that occurred through the membranes. It has not been possible to verify the usefulness of the equation mentioned in the case of nonporous membranes. As to porous membranes, a correction factor (of temperature) depending on the temperature is achieved from the thermoosmotic coefficient.

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Section: Analysis Of Resultsmentioning

confidence: 99%

Parameters that may Influence the Correction Factor in Membranes Subjected to Thermal Gradients

Vázquez‐González

Serrano

1992

Separation Science and Technology

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“…All of them were soaked in twice distilled and deionized water, and the remaining air was taken out as is indicated in [12]. The membranes which underwent this pre-treatment will be called M 0 .…”

Section: Membranesmentioning

confidence: 99%

“…Different membrane processes such as permeation, diffusion, thermo-osmosis, ultrafiltration or membrane potential have been studied, and some characteristic parameters of different cellophane membranes were determined (fixed charge density, transport numbers in the membrane, hydraulic and thermo-osmotic permeabilities, etc.) [6][7][8][9][10][11][12], Differences in some results, mainly in those involved with temperature dependence [7,8], were accounted for by the different nature or treatment of the membranes used.…”

Section: Introductionmentioning

confidence: 98%

Cellophane Membranes: Effect of their Treatment on the Permeability of Salts and the Membrane Potential

Benavente¹

1990

Journal of Non-Equilibrium Thermodynamics

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Membrane potential and diffusion of NaCl through treated and annealed Cellophane membranes have been studied. Some characteristic parameters of the different membranes such as salt permeability, fixed charge density and mobility ratio of the ions in the membranes were estimated. Salt permeability changes due to the treatment of the membranes have been obtained for the temperatures studied (25 and 55 °C). Results also show some differences in the fixed charge density values between treated and untreated membranes at 25 °C but very similar values have been found at 55 °C.

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“…To select the optimum fits, the same procedure as indicated in ref. (7) was followed. The results of the optimal fits are shown in table 1, where the functions B(T,, T,)/6 appear, in mol m-2 s-' K-' to permit a comparative analysis.…”

Section: Application Of the Theoretical Analysismentioning

confidence: 99%

“…Values of m: have been estimated for the 600P and 500P membranes in ref. (7) from microcalorimetric m e a s ~r e m e n t s ~~ and determinations of membrane water content at saturation. Only two temperatures were studied (33 and 45 "C) and the results obtained were fitted to a linear dependence on T. and -AH",J mol-1 = 374.6 -1.973 T rH",J mol-' = 97.7-1.104T for the 600P and 500P membranes, respectively.…”

Section: Zwt(t) =mentioning

confidence: 99%

Temperature dependence of thermo-osmosis. A solution model

Fernández‐Pineda¹,

Vázquez‐González²

1989

J. Chem. Soc., Faraday Trans. 1

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A model has been proposed to study the temperature dependence of the permeation and the thermo-osmosis of a single substance through a membrane. The model takes into account the dependence on temperature of the molar volume of permeant, the enthalpy of transfer from the permeant phase to the membrane phase, and the phenomenological coefficients defined for a thin slab of membrane. The empirical phenomenological coefficients, permeability and thermo-osmotic permeability of the discontinuous system are obtained as integral formulae of the abovementioned properties. A method has been proposed to evaluate the transport phenomenological coefficients, true for a thin slab of membrane, from the experimental data of the enthalpies of dissolution of permeant in the membrane, of the permeability and of the thermo-osmotic permeability. The experimental data reported in the literature and those obtained from our previous work fit well with this theoretical model, but it is recognized that new experimental results are needed to apply this model completely.

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Differential thermo-osmotic permeability in water–cellophane systems

Cited by 10 publications

References 1 publication

Parameters that may Influence the Correction Factor in Membranes Subjected to Thermal Gradients

Parameters that may Influence the Correction Factor in Membranes Subjected to Thermal Gradients

Cellophane Membranes: Effect of their Treatment on the Permeability of Salts and the Membrane Potential

Temperature dependence of thermo-osmosis. A solution model

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