Coupling of Mass Transfer and Chemical Reaction across an Asymmetric Sandwich Membrane

Meyer, Jörg; Sauer, Friedrich A.; Woermann, D.

doi:10.1007/978-3-642-65986-7_3

Cited by 9 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a discontinuous system being in a state of stationary flow, the equation of continuity states (Katchalsky and Curran 1965;Meyer et al 1974) that the chemical potential will be the same on both sides of the boundary separating the two phases (xylem and cells). However, the continuity of the chemical potentials across a dividing surface does not imply continuity of the gradients δµ w /δx at the surface.…”

Section: Theoretical Considerations and Evaluation Of The Current Datmentioning

confidence: 99%

Implications of mucilage on pressure bomb measurements and water lifting in trees rooting in high-salinity water

Zimmermann

Heidecker

et al. 2001

Trees

View full text Add to dashboard Cite

Various studies on mangroves and other tall trees rooting in high-salinity water have given compelling evidence that tension is not the only factor in water lifting as thought by plant physiologists. A characteristic feature of these trees is that the tissue cells, the apoplastic space and, in particular, the lumen and the inner walls of many xylem vessels of the roots, the trunk and the branches (up to the apex) contain mucilage. Data on single marine giant algal cells are presented that show that mucilage reduces the chemical activity of water. Longitudinal gradients in the chemical activity of water and interfacial forces are presumably the dominant forces for water lifting. In order to save water on its tortuous pathway to the uppermost foliage trees apparently use different strategies (as revealed by 1 H-NMR imaging), e.g. reduction of the conducting xylem area in the branches at intermediate height by mucilage or interruption of the xylem water columns by gas-filled segments and water lifting through mucilage networks and surface films. Pressure bomb experiments over the entire height of the trees revealed clearly that balancing pressure values cannot be taken as a measure for xylem tension. Such values can be used generally for an estimation of the chemical potential of water in the xylem of leafy twigs under atmospheric pressure, µ w,h=0 , provided that a species-specific "threshold pressure" (depending on wood density, elastic forces of the tissue, hydraulic coupling between xylem and tissue cells, intercellular spaces, cellular osmotic pressure etc.) is subtracted from the balancing pressure values. Transpiration increases the "threshold pressure" considerably and in an unpredictable way. Thus, as shown here, predawn balancing pressure data taken at various heights can yield information about the height dependence of µ w (measured at h=0) under field conditions, particularly when the water content of the xylem is simultaneously determined in a reliable manner (e.g. by the compression/decompression method in combination with centrifugation).

show abstract

Section: Theoretical Considerations and Evaluation Of The Current Datmentioning

confidence: 99%

Implications of mucilage on pressure bomb measurements and water lifting in trees rooting in high-salinity water

Zimmermann

Heidecker

et al. 2001

Trees

View full text Add to dashboard Cite

show abstract

“…14). The SELEMION and NAFION membranes used for the hyper filtration experiments have special structures to which this model cannot be applied (at least not for the treatment of hyper filtration experiments).…”

Section: Hyperfiltration Experimentsmentioning

confidence: 99%

Hyperfiltration of Acetonitrile/Water Mixtures Through Ion Exchange Membranes: Influence of Selective Solvation of Counterions on Selectivity

Philippsen

Woermann

1984

Ber Bunsenges Phys Chem

Self Cite

View full text Add to dashboard Cite

show abstract

Selektiver Stofftransport durch Membranen

Woermann

1979

Ber Bunsenges Phys Chem

View full text Add to dashboard Cite

Eine der Voraussetzungen für den Einsatz von Membranen bei Trennverfahren ist die Kenntnis ihrer Transporteigenschaften. Diese lassen sich am geeignetsten durch die Bestimmung der Matrix der phänomenologischen Transportkoeffizienten der linearen Ansätze der Thermodynamik irreversibler Prozesse für das betrachtete Membransystem charakterisieren. Die Methode wird an einem einfachen Membransystem erläutert. ‐ Um gezielt Membranen mit bestimmten Transporteigenschaften herstellen zu können, ist es wichtig, den Zusammenhang zwischen Membranstruktur und Transporteigenschaften zu verstehen. Zur Verdeutlichung dieses Gesichtspunkts werden Membranmodelle diskutiert, die einen Einblick in die physikalischen Ursachen der selektiven Membranpermeation geben.

show abstract

Coupling of Mass Transfer and Chemical Reaction across an Asymmetric Sandwich Membrane

Cited by 9 publications

References 3 publications

Implications of mucilage on pressure bomb measurements and water lifting in trees rooting in high-salinity water

Implications of mucilage on pressure bomb measurements and water lifting in trees rooting in high-salinity water

Hyperfiltration of Acetonitrile/Water Mixtures Through Ion Exchange Membranes: Influence of Selective Solvation of Counterions on Selectivity

Selektiver Stofftransport durch Membranen

Contact Info

Product

Resources

About