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http://nopr.niscpr.res.in/handle/123456789/17995| Title: | Excess adsorption on hydrophobic and hydrophilic solid-liquid interfaces. Positive excess adsorption of non-ionic surfactant. Part 1 |
| Authors: | Halder, Ebrahim Chattoraj, D K Dash, K P |
| Issue Date: | Dec-2006 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | The extent of adsorption ( ) of non-ionic surfactant
Tween-20 onto hydrophilic alumina and silica and hydrophobic charcoal surfaces has
been measured as a function of surfactant concentration (X2) in mole fraction unit at different
temperatures. For each isotherm, at low range of X2 increases with increase in surfactant
concentration. But, it reaches maximum ( ) when X2reaches a critical value X . With increase in temperature, increases
for charcoal and silica surfaces while it decreases for alumina surface. At 40°C,
at charcoal surface begins to decrease when X2 exceeds X. At 30°C for charcoal surface,
increases sharply with increase in X2 without reaching any limiting
value due to the multilayer adsorption of Tween-20. Similar formation of multilayers
is also observed at alumina-water interface when the surface coverage is significantly
low. Fomation of multilayers of Tween-20 molecules on the surface of silica is not
observed even when X2 is relatively high. Using the
integrated form of the Gibbs ad sorption equation. the standard free energy
change ΔGo for the adsorption of non-ionic surfactant per square
meter of powdered surface due to the change of the bulk activity of Tween-20
from zero to unity has been evaluated and critically examined. |
| Page(s): | 2591-2598 |
| ISSN: | 0975-0975(Online); 0376-4710(Print) |
| Appears in Collections: | IJC-A Vol.45A(12) [December 2006] |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| IJCA 45A(12) 2591-2598.pdf | 1.79 MB | Adobe PDF | View/Open |
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