scholarly journals Simulation of S-Entropy Production during the Transport of Non-Electrolyte Solutions in the Double-Membrane System

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 463
Author(s):  
Andrzej Ślęzak ◽  
Wioletta M. Bajdur ◽  
Kornelia M. Batko ◽  
Radomir Šcurek
Keyword(s):  
Entropy Production ◽  
Transport Theory ◽  
Membrane System ◽  
Electrolyte Solutions ◽  
Solute Flux ◽  
Initial Moment ◽  
Hydraulic Permeability ◽  
Transport Parameters ◽  
Double Membrane ◽  
Solute Permeability

Using the classical Kedem–Katchalsky’ membrane transport theory, a mathematical model was developed and the original concentration volume flux (Jv), solute flux (Js) characteristics, and S-entropy production by Jv, ( ( ψ S ) J v ) and by Js ( ( ψ S ) J s ) in a double-membrane system were simulated. In this system, M1 and Mr membranes separated the l, m, and r compartments containing homogeneous solutions of one non-electrolytic substance. The compartment m consists of the infinitesimal layer of solution and its volume fulfills the condition Vm → 0. The volume of compartments l and r fulfills the condition Vl = Vr → ∞. At the initial moment, the concentrations of the solution in the cell satisfy the condition Cl < Cm < Cr. Based on this model, for fixed values of transport parameters of membranes (i.e., the reflection (σl, σr), hydraulic permeability (Lpl, Lpr), and solute permeability (ωl, ωr) coefficients), the original dependencies Cm = f(Cl − Cr), Jv = f(Cl − Cr), Js = f(Cl − Cr), ( Ψ S ) J v = f(Cl − Cr), ( Ψ S ) J s = f(Cl − Cr), Rv = f(Cl − Cr), and Rs = f(Cl − Cr) were calculated. Each of the obtained features was specially arranged as a pair of parabola, hyperbola, or other complex curves.

scholarly journals Thermo-osmosis in Membrane Systems: A Review

2017 ◽  
Vol 42 (3) ◽  
Author(s):  
V. María Barragán ◽  
Signe Kjelstrup
Keyword(s):  
Waste Heat ◽  
Osmotic Coefficients ◽  
Membrane System ◽  
Electrolyte Solutions ◽  
Volume Transport ◽  
Experimental Program ◽  
Pure Liquid ◽  
Hydraulic Permeability ◽  
Hydrophilic Membranes ◽  
Entropy Of Adsorption

AbstractWe give a first review of experimental results for a phenomenon little explored in the literature, namely thermal osmosis or thermo-osmosis. Such systems are now getting increased attention because of their ability to use waste heat for separation purposes. We show that this volume transport of a solution or a pure liquid caused by a temperature difference across a membrane can be understood as a property of the membrane system, i. e. the membrane with its adjacent solutions. We present experimental values found in the literature of thermo-osmotic coefficients of neutral and hydrophobic as well as charged and hydrophilic membranes, with water and other permeant fluids as well as electrolyte solutions. We propose that the coefficient can be qualitatively explained by a formula that contains the entropy of adsorption of permeant into the membrane, the hydraulic permeability, and a factor that depends on the interface resistance to heat transfer. A variation in the entropy of adsorption with hydrophobic/hydrophilic membranes and structure breaking/structure making cations could then explain the sign of the permeant flux. Systematic experiments in the field are lacking and we propose an experimental program to mend this situation.

Nonlinear Effects in Osmotic Volume Flows of Electrolyte Solutions through Double-Membrane System

2011 ◽  
Vol 92 (2) ◽  
pp. 337-356 ◽  
Author(s):  
A. Ślęzak ◽  
J. Jasik-Ślęzak ◽  
S. Grzegorczyn ◽  
I. Ślęzak-Prochazka
Keyword(s):  
Nonlinear Effects ◽  
Membrane System ◽  
Electrolyte Solutions ◽  
Double Membrane

Membrane Transport in Concentration Polarization Conditions: Evaluation of S-Entropy Production for Ternary Non-Electrolyte Solutions

2020 ◽  
Vol 45 (4) ◽  
pp. 385-399
Author(s):  
Andrzej Ślęzak ◽  
Sławomir Grzegorczyn ◽  
Kornelia M. Batko ◽  
Wiesław Pilis ◽  
Robert Biczak
Keyword(s):  
Aqueous Solutions ◽  
Osmotic Pressure ◽  
Entropy Production ◽  
Pressure Difference ◽  
Concentration Polarization ◽  
Electrolyte Solutions ◽  
Linear Functions ◽  
Initial Moment ◽  
Solute Fluxes ◽  
Osmotic Pressure Difference

AbstractA model of the S-entropy production in a system with a membrane which separates non-electrolyte aqueous solutions was presented. The differences between fluxes in non-homogeneous and homogeneous conditions for volume and solute fluxes, respectively, are non-linear functions of the glucose osmotic pressure difference (OPD) in ranges dependent on the initial ethanol OPD. A decrease of ethanol OPD causes a shift of this range into the lower values of glucose OPD; this shift is also observed for negative values of glucose and ethanol OPDs. The coefficient of concentration polarization of the membrane as a function of glucose OPD has a sigmoidal shape. For suitably great negative values of glucose OPD this coefficient is very small, while for suitably high positive glucose OPD this coefficient is equal to 0.5. An increase of ethanol OPD at the initial moment causes a shift of this curve towards the direction of positive values of glucose OPD. In turn the S-entropy production in non-homogeneous conditions has low values for negative values of glucose OPD (convective range) while for suitably high positive glucose OPD it has greater values (diffusive and convective range). A change of ethanol OPD at the initial moment causes a shift of this curve along the horizontal axis.

Zoospore ultrastructure in the genus Rhizophydium (Chytridiales)

1978 ◽  
Vol 56 (19) ◽  
pp. 2380-2404 ◽  
Author(s):  
D. J. S. Barr ◽  
V. E. Hadland-Hartmann
Keyword(s):  
Membrane System ◽  
Double Membrane ◽  
Lipid Globule ◽  
Lateral Posterior ◽  
Membrane Bound ◽  
Relationship Of ◽  
The Relationship ◽  
Posterior Position ◽  
Compact Cluster ◽  
Peripheral Cytoplasm

The zoospore ultrastructure of 12 species of Rhizophydium is described. Species include the following: R. chlorogonii (Serbinow) Jaczewski; R. constantineani Saccardo; R. haynaldii (Schaarschmidt) Fischer; R. capillaceum Barr; two morphologically and cytologically different species, each previously identified as R. sphaerotheca Zopf; R. patellarium Scholz; R. biporosum (Couch) Barr; R. subangulosum (Braun) Rabenhorst; R. laterale (Braun) Rabenhorst; R. sphaerocarpum (Zopf) Fischer var. spirogyrae Barr; and two isolates of R. pollinis-pini (Braun) Zopf. The Rhizophydium zoospore is basically similar to the Chytridium zoospore having (1) the nucleus, a compact cluster of ribosomes, one or more mitochondria, and a microbody – lipid globule complex compartmentalized into the core of the zoospore by a double membrane system and (2) two to five microtubules connecting one side of the kinetosome to the rumposome on the lipid globule surface and thus anchoring the lipid globule in a lateral–posterior position in the zoospore. Rhizophydium patellarium does not have kinetosome-associated microtubules or a rumposome but does have the membrane-bound core area. In all species, a microbody and mitochondrion are associated with the lipid globule. The number of mitochondria varies from 1 in some species to several or to over 30 in other species. In one isolate of R. pollinis-pini, there is 1 large mitochondrion and in the other there were 30–35 small mitochondria. The peripheral cytoplasm of all species contains clusters of vesicles or endoplasmic reticulum which bud from the double membrane system, vesicles of moderate electron density, and vacuoles of various sizes; R. capillaceum, R. patellarium, and R. subangulosum have in addition vesicles which contain very electron-dense material. Rhizophydium capillaceum and R. sphaerocarpum zoospores have virus-like particles and the R. biporosum zoospore contains a paracrystalline body. The taxonomic significance of the observations and the relationship of Rhizophydium to other chytrids are stressed in the Discussion.

scholarly journals Preparation of defect free TFC FO membranes using robust and highly porous ceramic substrate

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Jincai Su ◽  
Yanyan Wei ◽  
Hui Li
Keyword(s):  
Osmotic Pressure ◽  
Interfacial Polymerization ◽  
Pure Water ◽  
Porous Ceramic ◽  
Water Flux ◽  
Solute Flux ◽  
Structural Parameter ◽  
Solute Permeability ◽  
Draw Solution ◽  
Surface Pores

In this study, robust and defect-free thin film composite (TFC) forward osmosis (FO) membranes have been successfully fabricated using ceramic hollow fibers as the substrate. Polydopamine (PDA) coating under controlled conditions is effective to reduce the surface pores of the substrate and make the substrate smooth enough for the interfacial polymerization. The pure water permeability (A), solute permeability (B) and structural parameter (S) of the resultant FO membrane are 0.854 L·m-2h-1bar-1 (LMH/Bar) 0.186 L·m-2h-1 (LMH) and 1720 µm, respectively. The water flux and reverse draw solute flux are measured using NaCl and proprietary ferric sodium citrate (FeNaCA) draw solutions at low and high osmotic pressure ranges. With increasing the osmotic pressure, higher water flux is obtained but its increase is not directly proportional to the increase in the osmotic pressure. At the membrane surface, the effect of dilutive concentration polarization is much less serious for FeNaCA draw solutions. At an osmotic pressure of 89.6 bar, the developed TFC membrane generates water fluxes of 11.5 and 30.0 LMH using NaCl and synthesized FeNaCA draw solutions. The corresponding reverse draw solute flux is 7.0 g·m-2h-1 (gMH) for NaCl draw solution but it is not detectable for FeNaCA draw solution. This means that the developed TFC FO membranes are defect free and their surface pores are at molecular level. The performance of the developed TFC FO membranes are also demonstrated for the enrichment of BSA protein.

scholarly journals Electro-Osmotic Behavior of Polymeric Cation-Exchange Membranes in Ethanol-Water Solutions

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 692
Author(s):  
V. María Barragán ◽  
Juan P. G. Villaluenga ◽  
Víctor Morales-Villarejo ◽  
M. Amparo Izquierdo-Gil
Keyword(s):  
Cation Exchange ◽  
Streaming Potential ◽  
Membrane System ◽  
Electrolyte Solutions ◽  
Joule Effect ◽  
Potential Coefficient ◽  
Water Solutions ◽  
Onsager Reciprocity ◽  
Ethanol Content ◽  
Reciprocity Relations

The aim of this work is to apply linear non-equilibrium thermodynamics to study the electrokinetic properties of three cation-exchange membranes of different structures in ethanol-water electrolyte solutions. To this end, liquid uptake and electro-osmotic permeability were estimated with potassium chloride ethanol-water solutions with different ethanol proportions as solvent. Current–voltage curves were also measured for each membrane system to estimate the energy dissipation due to the Joule effect. Considering the Onsager reciprocity relations, the streaming potential coefficient was discussed in terms of ethanol content of the solutions and the membrane structure. The results showed that more porous heterogeneous membrane presented lower values of liquid uptake and streaming potential coefficient with increasing ethanol content. Denser homogeneous membrane showed higher values for both, solvent uptake and streaming coefficient for intermediate content of ethanol.

Transient analysis of macromolecular transport across microvascular wall and into interstitium

1993 ◽  
Vol 265 (3) ◽  
pp. H993-H999 ◽  
Author(s):  
D. Kim ◽  
P. M. Armenante ◽  
W. N. Duran
Keyword(s):  
Molecular Diffusion ◽  
Fluid Velocity ◽  
Calcium Ionophore ◽  
Convective Transport ◽  
Cheek Pouch ◽  
Solute Flux ◽  
Ionophore A23187 ◽  
Transport Parameters ◽  
Macromolecular Transport ◽  
Dextran 70

We studied the dynamics of macromolecular transport across the microvascular wall in the hamster cheek pouch using intravital microscopy and digital video-image analysis. We used fluorescein isothiocyanate-dextrans of 70,000 and 150,000 Da (FITC-Dextran 70 and 150, respectively) as tracers. We applied our mathematical model and our in vivo calibration to determine the diffusion coefficient (D) and the average fluid velocity (V) in the microvascular wall and in the interstitium from the experimental data. The value of D for FITC-Dextran 70 was 0.90 +/- 0.04 x 10(-11) cm2/s in the wall and 1.29 +/- 0.05 x 10(-8) cm2/s in the interstitium. In both regions, V was 2.05 +/- 0.05 x 10(-8) cm/s. The transport parameters for FITC-Dextran 150 were 0.27 +/- 0.02 x 10(-11) cm2/s, 0.55 +/- 0.05 x 10(-8) cm2/s, and 1.71 +/- 0.48 x 10(-8) cm/s for D in the wall and interstitium and V, respectively. The topical application of either calcium ionophore A23187 (7 x 10(-7) M) or bradykinin (5 x 10(-7) M) increased D for FITC-Dextran 70 and 150 2-fold and V 10-fold relative to their control values. We used these values to quantify the relative importance of the diffusive and convective mechanisms in the total solute flux. Molecular diffusion dominates convective transport in both the microvascular wall and the interstitial space.

scholarly journals Effects of solvent and solute drag on transmembrane diffusion.

1982 ◽  
Vol 79 (3) ◽  
pp. 507-528 ◽  
Author(s):  
J T Van Bruggen ◽  
B Chalmers ◽  
M Muller
Keyword(s):  
Solute Drag ◽  
Tracer Diffusion ◽  
The Other ◽  
Solute Flux ◽  
Solvent Drag ◽  
Solution Flow ◽  
Solute Permeability ◽  
Drag Forces ◽  
Transmembrane Diffusion

The present study compares and quantitates both solvent drag and solute drag forces in a system with both heteropore and homopore membranes. It is shown that tracer solute permeability can be increased if solution flow or driver solute flux is in the direction of tracer diffusion. Either force can decrease tracer permeability if the force can decrease tracer permeability if the force is opposite to the direction of tracer diffusion. The two forces can be additive or one force may reduce the effect of the other force. In the particular system quantitated, solute drag is shown to be some 300 times more effective than solvent drag on a mole-to-mole basis. The use of a number of solute pairs on other homopore and heteropore membranes confirms the finding that the two drag forces can be analyzed or manipulated in a variety of systems.

scholarly journals DISCRETE-TIME MODELLING OP DISPERSION IN ESTURARIES

1980 ◽  
Vol 1 (17) ◽  
pp. 182
Author(s):  
T. Wood
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
High Speed ◽  
Transport Theory ◽  
State Parameter ◽  
Space Time ◽  
Tidal River ◽  
Primary Concern ◽  
Transport Parameters ◽  
Partial Differential

This paper aims to put forward a case in favour of a simple discretetime model describing mixing in an estuary. The model derives from the remarkably simple concepts developed by Ketchum (1951 a,b) which describe mixing in terms of tidal prism exchanges between segments. The author's view is that Ketchum1s ideas were abandoned before they were fully explored. A major factor was the advent of the high-speed computer which opened up the possibility of using an approach based on the space-time formulation of the problem in terms of the partial differential equations of transport theory. Intrinsically this approach, based on a continuum description, is more attractive than a gross description based on relatively large segments: one obvious reason is the possibility of providing a comprehensive space-time prediction of the spread of a pollutant. In practice, though, significant problems arise in its use: in particular, the following can be mentioned - a) substantial computing costs relating to computer program development and machine time b) specification of transport parameters inherent in the partial differential equations of transport: for example, dispersion coefficients c) model validation and state/parameter estimation. The last of these is the primary concern of this paper. It is probably true to say that, to date, too little attention has been given to these topics, in the context of estuarine modelling. The point to be made is that there is small justification in using a sophisticated description of a system if the resulting predictions of the model cannot be effectively validated. The ideas used in this paper stem from those put forward by Beck and Young (1975) in studies on non-tidal river pollution. The subsequent discussion suggests an extension to estuarine systems-.

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