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  • Articles: DFG German National Licenses  (4)
  • 1975-1979  (4)
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  • Articles: DFG German National Licenses  (4)
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 256 (1978), S. 62-77 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Die Wechselwirkung von Ionenaustauschermembranen mit grenzflächenaktiven Stoffen wird durch Elektrodialyse untersucht. Der elektrische Widerstand der Membranen steigt während der Elektrodialyse beträchtlich an, wenn die grenzflächenaktiven Ionen entgegengesetzte Ladungen wie die Austauschergruppen der Membranen haben. Es wurde gefunden, daß 1. die Adsorption oder der Ionenaustausch der grenzflächenaktiven Ionen an der Membran beträchtlich durch das elektrische Feld verstärkt wird; 2. die Zunahme des elektrischen Widerstandes groß ist, wenn das grenzflächenaktive Ion ein hohes Molekulargewicht hat und möglichst sperrig ist; 3. die Widerstandsänderung merklich von der Art der Membran beeinflußt wird. Auf Grund dieser Versuche wurde die Möglichkeit geprüft, die Zunahme des Membranwiderstandes bei Gegenwart grenzflächenaktiver Stoffe durch Adsorption von Polyelektrolyten zu reduzieren.
    Notes: Summary Interaction between ion exchange membranes and surface active agents was observed by electrodialyzing the salt solution containing the surface active agent. The behavior of the electric resistance of the membrane during the electrodialysis, the current efficiency and the adsorbed or ion-exchanged amount and the permeated amount of the surface active agent were observed. Generally, the electric resistance of the membrane during the electrodialysis increased remarkably when the ionic surface active agent having the opposite charge to ion-exchange groups of the membrane was contained in the solution. And the correlation of the behavior of the electric resistance of the membrane to the electrodialysis condition, species of surface active agents and species of membranes was mainly observed. Results were as follows. 1) The adsorption' or ion-exchange of ionic surface active agent on the membrane was remarkably emphasized by the electric field. 2) The degree of the increase in the electric resistance of the membrane was remarkable when the surface active agent had the high molecular weight and the bulky molecular structure. 3) The degree of the increase in the electric resistance was remarkably various according to species of the membranes. From these results, a protecting method for the change of these membrane properties was examined. When the ion exchange membrane was treated with the polyelectrolyte solution having the opposite charge to ion exchange groups of the membrane, the increase in the electric resistance by ionic surface active agent was depressed. Generally, though the change of electrodialysic properties of the membrane by the ionic surface active agent was remarkable in the membrane having the tight structure, the change of the properties of the membrane having the tight structure was easy to be protected by the polyelectrolyte treatment. Though the ionic surface active agent having the bulky molecular structure made the properties of the membrane change remarkably, the change of the properties of the membrane by the bulky surface active agent could be easily protected by the polyelectrolyte treatment.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 1199-1213 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When a cation exchange membrane is immersed in a cationic polyelectrolyte solution to form a thin layer on the membrane surface, the membrane properties are changed: permselectivity between cations with different electric charges (a relative transport number of the calcium ions to sodium ions, PNaCa), current efficiency, and electric resistance of the membrane. Here the more compact the cationic polyelectrolyte layer, the more outstanding the change in permselectivity. To make a more compact layer, an electrodeposition method was adopted and a change in the permselectivity of the resultant cation exchange membrane was investigated. By using the electrodeposition method a strongly basic polyelectrolyte with a larger molecular weight effectively changed the permselectivity of the cation exchange membrane: the PNaCa value dropped to about 0.3 from about 2.5 of the PNaCa of the untreated membrane during electrodialysis of the sodium chloride - calcium chloride system, and an increase in the electric resistance of the membrane (i.e., organic fouling) due to a cationic surface-active agent could be prevented. It is noteworthy that by using the strongly basic polyelectrolyte with a larger molecular weight the electrodeposition method was effective, whereas the immersion method was ineffective. Furthermore, even with the electrodeposition method the cationic polyelectrolyte which had a relatively smaller molecular weight resulted in a more remarkable change in the PNaCa value than did that with a larger molecular weight. In the electrodeposition method the amount of polyelectrolyte cohered onto the membrane surface in creased with an increase in the concentration of the polyelectrolyte, and weakly basic polyelectrolyte, and weakly basic polyelectroyte (polyethyleneimine) was also available independent of its molecular weight.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 1063-1080 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A change in electrodialytic transport properties of various cation exchange membranes was observed after the membranes had been adsorbed or ion-exchanged with various cationic polyelectrolytes. Transport properties measured in this report were the relative transport number of calcium ion to sodium ion PCaNa, the current efficiency of cations, and the electric resistance of the membrane during the electrodialysis. Weakly basic and strongly basic cationic polyelectrolytes of various molecular weights were used. Though PCaNa of any cation exchange membrane decreased by the adsorption or ion exchange of any cationic polyelectrolyte, the degree of the decrease in PCaNa changed with species and molecular weight of polyelectrolytes and species of cation-exchange membranes. Weakly basic polyelectrolytes and low molecular weight, strongly basic polyelectrolytes were effective in producing a marked decrease in PNaCa of any cation exchange membrane. The effect of strongly basic polyelectrolytes of high molecular weight on PCaNa was weak in most cases. However, if it was possible to make the polyelectrolyte adhere to the surface of the membrane to form a compact coiled structure, any cationic polyelectrolyte was effective in producing a remarkable decrease in PCaNa of any cation-exchange membrane.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrodialytic behavior of cation exchange membrane having cationic polyelectrolyte layer on its surface (relative transport number between two cations, PM1M2, current efficiency, and electric resistance of the membrane during the electrodialysis) was measured using various cations, and the mechanism of selective permeation of lower-valent cations than the higher and of larger hydrated cations than the smaller was investigated. The following conclusions were obtained: (1) the cationic polyelectrolyte layer narrowed the pathway for ions; (2) when the pathway was made narrower by other methods, the remarkable change of the permselectivity of the membrane did not occur; (3) the effectiveness of the cationic polyelectrolyte layer was depressed by the treatment with anionic polyelectrolytes to neutralize the cationic charge on the membrane surface; and (4) the cation with larger hydrated diameter (potassium ions) more easily permeated through the membrane having the polyelectrolyte layer than that with the smaller hydrated diameter (sodium ions). It is concluded that the change of PM1M2 by the cationic charge layer on the membrane surface is based on the difference in the strength of the electrostatic repulsion between two cations against the cationic charge layer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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