12 research outputs found
Adsorption kinetics of Brij 35 at air/solution interface
2051-2054Dynamic surface tension and surface adsorption
kinetics at the air/aqueous solution interface of dodecyl polyoxyethylene(23) ether
(Brij®35, C12H25O(CH2CH2O)23H)
have been investigated at different bulk surfactant concentrations and temperatures.
Apparent diffusion coefficients, Da, activation barrier, εa,
and the adsorption kinetic parameters, n and t*, are obtained from
the extended Ward and Tordai approach, and Rosen's empirical model, respectively.
It is shown that Brij 35 solutions follow a mixed diffusion-activation
adsorption mechanism. Results evaluated by the extended Ward and Tordai approach
are consistent with those obtained from Rosen's empirical model With increase in
bulk concentration from 0.1 CMC to 10 CMC (mol/dm3) εa
increases from 2.40 to 6.96 kJ/mol, and n decreases from 0.620 to 0.393,
while with increase in temperature from 25 to 45°C, εa decreases
from 4.59 to 3.54 kJ/mol, and n decreases from 0.534 to 0.456. This
indicates that the diffusion tendency
decreases with increase in the interaction
between surfactant molecules while the thermo-motion of the molecules favours surface
adsorption