Diffusion mechanism of direct dyes into a cellulose membrane: The structural effect of direct dyes on the adsorption rate

Abstract

SynopsisThe transport of three typical direct dyes, C.I. Direct Yellow 12, C.I. Direct Red 2, and C.I.Direct Blue 15, into a cellulose membrane has been studied at 55°C. Sodium chloride was used as a stimulator for dyeing. The effects of the concentration of the stimulator on the adsorption isotherms, the adsorption rate, and the concentration profiles in the membrane were tested. The experimental adsorption rates of three dyes were quite different. The diffusion mechanism of the dyes into a cellulose membrane was analyzed on the basis of the parallel transport equation of surface and pore diffusion as developed in our previous paper. The experimental uptake curves showed good agreement with the theoretical curves for surface diffusion control. Experimental concentration profiles also agreed reasonably well with the theoretical lines for surface diffusion control rather than pore diffusion control. The surface diffusivities of three dyes were quite different and nearly independent of the adsorbed phase concentration of the dye.

Adsorption isotherm models for basic dye adsorption by peat in single and binary component systems

“…In relation to adsorption systems involving the extraction of large organic compounds and dyes from aqueous solution the Langmuir and Freundlich isotherm expressions are most commonly used [40][41][42][43]. However, in adsorption systems, the relative size of the sorbate molecule and the molecular sieving effect of the sorbent have been shown to affect the equilibrium of the system [44][45][46].…”

Intraparticle diffusion of phosphates in OH‐type strongly basic ion exchanger

“…They also studied an intraparticle mass transfer in a bidispersed porous ion exchanger by mutual ion exchange . To prove a parallel transport of surface and pore diffusions, extensive studies on the mass transport of various direct dyes through porous cellulose membranes were previously conducted (Gutsche and Yoshida, 1994;Maekawa et al, 1989;Nango et al, 1989;Yoshida et al, 1986Yoshida et al, , 1989Yoshida et al, , 1991. They measured not only uptake curves but also concentration profiles and theoretically proved the existence of a parallel transport by using the experimental uptake curves and concentration profiles.…”

Analytical staining of cellulosic materials: A review

“…Uptake of dye clearly depends on both chemical and physical aspects, and such issues will be considered. Mechanisms of coloration and staining have been considered in the following articles (Griffiths 1982;Maekawa et al 1989;Yu et al 1995;El-Shafei et al 2011). A search of the literature indicated a need for publication of general background information in this area.…”

“…In some other studies the researchers made the assumption that the depth of staining depended more on whether or not the presumed adsorption sites could be reached by a diffusion mechanism, rather than being obstructed by dead-end pores or pores too small to allow passage (Maekawa et al 1989;Kim et al 2004;Yang et al 2013;Khatri et al 2014;Luterbacher et al 2015a). For instance, Luterbacher et al (2015a) used confocal laser scanning microscopy to support a mechanism by which the enzymatic widening of pores within lignocellulosic substrates tended to increase the rate at which dyes were able to permeate into the material.…”

“…Because cellulose is the most prominent polymer within woody materials, it makes sense to start by considering what dyes are attracted to it. There are many references indicating a preferential adsorption of direct dyes onto cellulose, either in the pure form of cellulose or when it is believed to be exposed at surfaces accessible to the aqueous media (Peters and Vickerstaff 1948;Simons 1950;Kitamura and Kyoshi 1971;Choi and Oday 1984;Maekawa et al 1989;Bairathi 1993;Gutmann 1995;Drnovsek and Perdih 2005a;Lewis 2009;Anderson et al 2010;Chandra and Saddler 2012;Ursache et al 2018). Factors affecting the adsorption of direct dyes onto cellulose-based materials have been reviewed (Safa and Bhatti 2010;Hubbe et al 2012a).…”