The Effect of a Surface Barrier on Uptake Rates of Dye into Wool Fibers

Abstract

It is shown that any surface barrier to the entry of a dye into a fiber must modify the form of the uptake-time relation, the barrier exerting its greatest influence in the early stages of sorption, but becoming progressively less important as sorption proceeds. This is manifested by an initially concave-upwards tendency in the uptake-timel curve.The analysis, which takes account of variable diffusion characteristics of fibers forming the ~asemhly, is applied to the uptake of Naphthalene Orange G by wool, and a small but definite effect is found, which could for instance be attributed to the epicuticle..

Kinetics and mechanism of adsorption of methylene blue from aqueous solution by nitric-acid treated water-hyacinth

“…It is also observed that the value of the intercept increases from 46.83 to 261.6 when C o is increased from 97 to 1187 mg/L, which indicates that the thickness of the boundary layer increases significantly with increase of C o . The multilinear nature of the intraparticle diffusion plots suggests the predominance of external mass transfer of MB at the beginning of adsorption [24]. The rate constants of external mass transfer were calculated using the plot of C/C o against time at different initial MB concentrations (figure not shown).…”

Lipid Role in Wool Dyeing

“…On heating the dyebath to 90 °C in order to achieve fiber penetration, no significant effect of the plasma treatment on the extent of uptake or levelness of a relatively hydrophilic dye was observed as equilibrium conditions were approached. Extraction of normally scoured wool with lipid solvents also increases the dyeing rate (Medley & Andrews, 1959;Joko et al, 1985;Lindberg, 1953). This observation supports the concept that a lipid barrier to wool dyeing exists located at, or near, the fiber surface.…”

A Study of Wool Carbonizing

“…Hampton and Rattee [4] used this relationship to study the surface barrier effects on wool dyeing. Medley [8] used the asymptotic equation of the semi-infinite model to study wool dyeing and used -D/a to indicate the surface barrier to wool dyeing as shown in Figure 1. The greater the value D/a, the greater the surface barrier effect on dyeing.…”