Adsorption Of Dyestuffs Research Articles

The adsorption of dyestuffs from aqueous solutions using activated carbon. iii. intraparticle diffusion processes

AbstractThe rate of dye removal from aqueous solution has been found to vary linearly with the square root of time for much of the adsorption period. A rate parameter, k, has been defined to explain intraparticle diffusion on a quantitative basis. This rate parameter has been correlated against the process variables thus providing useful design data.

The adsorption of dyestuffs from aqueous solutions using activated carbon. iv. external mass transfer processes

AbstractThe parameters affecting the mass transfer coefficients for external transport of dyes from water on to activated carbon particles have been studied. The external mass transfer coefficients have been determined and correlated as the dimensionless mass transfer term, Sh/Sc0.33. The dimensionless function has been found to vary linearly with agitation, initial dye concentration, particle size, adsorbent mass on log‐log coordinates, while reciprocal variation was obtained with absolute temperature. Activation energies were determined for the surface process, for the adsorption of Deorlene Yellow, Victoria Blue, Telon Blue and Disperse Blue 7 and found to be 26.5, 24.5. 25.4 and 74.6 kJ mol‐l respectively.

The adsorption of dyes in chitin. III. Intraparticle diffusion processes

AbstractIntraparticle diffusion processes for the adsorption of dyestuffs onto chitin have been studied. The amount of dye adsorbed per gram of chitin has been plotted against the square root of time. The slope of this plot is linear and has been defined as a rate parameter k. This rate parameter has been determined for a number of process variables, including initial dye concentration, agitation, chitin particle size, chitin mass, temperature, and solution pH. However, sometimes two and even three linear regions are apparent on the root time plots indicating a possible branched pore mechanism. The controlling mechanisms are due to macropores and micropores in the chitin particle creating rapidly and slowly diffusing regions.

Adsorption of dyestuffs onto chitin. External mass transfer processes

AbstractThe effect of several variables on the adsorption rate of four dyestuffs onto chitin was studied. A model is proposed enabling the film mass transfer coefficients to be determined. The coefficients were independent of initial dye concentration, chitin mass, chitin particle size, and temperature; a slight dependence with agitation was obtained. The film mass transfer coefficients at 400 rpm were 2.8×10−3, 2.9×10−3, 3.9×10−3, and 0.9×10−3 cm/s for Acid Blue 25, Acid Blue 158, Mordant Yellow 5, and Direct Red 85, respectively.

Adsorption of dyestuffs from aqueous solutions with activated carbon II: Column studies and simplified design models

AbstractThe design of batch contact and fixed‐bed adsorption systems has been discussed. A simplified design model (the Bed‐Depth Service Time model) has been proposed and tested. The effects of bed depth, dye flow rate and carbon particle size, for the adsorption of Telon Blue and Deorlene Yellow, have been correlated with this design procedure.

Adsorption of dyestuffs from aqueous solutions with activated carbon I: Equilibrium and batch contact‐time studies

AbstractThe ability of one activated carbon to remove dyestuffs from aqueous solutions has been investigated. The range of dyestuffs includes acidic, basic, disperse and direct dyes, and several factors have been studied, namely, agitation, initial dye concentration, adsorbent concentration, adsorbent particle‐size range, dye solution temperature, pH of solution and salt concentration.

EFFECTS OF ORIENTATION OF HELICAL ROD AND OF ELECTROST ATIC NATURE OF DYESTUFF ON DIFFUSION IN POLYPEPTIDE MEMBRANE

Diffusion of dyestuff in “random oriented” and “oriented” poly (γ-methyl L-glutamate) (PMLG) membranes was studied. In the former membrane, helical rods orient randomly in the palne parallel to the membrane surface. In “oriented” membrane prepared by applying the electric field to EDC solution of PMLG, helical rods orient parallel to both of the membrane surface and electric field. The diffusion of dyestuff observed as the concentration gradient in the membrane, was analysed referring to the gradient calculated on the assumption of concentration dependent diffusion coefficient. This dependence corresponds to the diffusion with Langmuir type adsorption of dyestuff. The coefficient obtained in the direction parallel to the helical rod is a few times larger than that in perpendicular direction. From the geometrical consideration of the diffusion model, it is suggested that the aperture between helical rods is smaller than that obtained by X-ray analysis. Using electropositive Methylene Blue and electronegative Alizarine Red S, the effect of electrostatic nature of dyestuff on the diffusion in slightly electronegative PMLG side chain region was examined. The results suggest that Alizarine Red S may diffuse through a narrow, low affinity region rapidly, Methylene Blue may diffuse slowly through a more broad, high affinity region. This difference is exaggerated when the direction of diffusion is parallel to the helical rod.

染色浴中の妨害イオンのイオン交換樹脂による除去について

The previous paper described that the proceeding of dyestuff adsorption was not satisfactory by the blending of various kinds of ions in the dye bath. In particular, the effect was greater by blending of organic acids.This paper describes the elimination of obstructive ions in the bath with ion exchange resins. It was found that sulfate, oxalate, acetate, and citrate ions were easily removed; however, when aluminum ions were blended in the bath, a large quantity of dyestuffs were adsorbed on aluminum hydroxide.In order to eliminate the effect, the precipitation of aluminum hydroxide was prevented by the addition of EDTA or sulfosalicylic acid in the amount corresponding to the aluminum concentration.

Humification of straw at different nitrogen levels followed by acriflavine adsorption and light absorption

Humic compounds isolated from decomposing wheat and rye straw, incubated for different periods with and without nitrogen added, were investigated for their acriflavine adsorption capacity and light absorption property. In the first instance, it was established that the degree of dyestuff adsorption on the acid-precipitable humic compounds is correlated with the extent in optical density of the total humus extracted by weak alkaline solution.

染色浴中の各種イオンの影響とその除去について

染色浴中の各種イオンの影響とその除去について

陽極酸化皮膜の染料吸着性について

The dyestuff adsorption of anodic oxide coating depended upon the conditions of anodizing and dyeing. The effects of the coating from mixed bath of sulfuric, oxalic, and citric acids on dyestuff adsorption were investigated by experiments under various conditons.The following results were obtained:(1) The coating was more porous and adsorption capacity of dyestuffs was more improved when the temperature and concentration of the bath were higher.(2) In general, the adsorption capacity was higher with the increase of anodizing time, but it was remarkably lowered when the current density was higher.(3) The adsorbed amount of dyestuffs was increased when their concentration and temperature wece higher, but it tended to be decreased when they were too high. Adjustment of pH had a significant effect, which gave the best result at a value of approximate to 4.(4) It was observed that the real surface area of the film of 20μ in thickness was 195-368 times as large as its apparent surface area. The amount of dyestuffs adsorbed on the real surface was smaller than 0.091mg/dm2.

Adsorption of dyestuffs by hydrous thorium oxide: Heat of adsorption of the dyes by various samples of the hydroxide

Heats of adsorption of Congo Red and Fuchsine by various samples of hydrous thorium oxide have been calculated. The order of the heats of adsorption is in conformity with the order of the specific adsorption of the dyes by the samples.

PHYSICOCHEMICAL STUDIES OF LIGNINSULPHONATES: II. BEHAVIOR AS POLYELECTROLYTES

Conductivity, dyestuff adsorption, and viscosity measurements on aqueous solutions of fractionated ligninsulphonate samples having various molecular weights indicate that they behave as flexible polyelectrolytes. There is evidence that ligninsulphonates of molecular weight less than 5000 associate in solution in a manner analogous to micelle formation in colloidal electrolytes. From the variation of intrinsic viscosity with molecular weight, it may be concluded that the degree of molecular branching of the high molecular weight ligninsulphonates is greater than that of the low molecular weight fractions.

THE INFLUENCE OF THE INTENTIONAL TENSION DIFERENCES DURING PREPARATION AND WEAVING TO THE DEFECTS OF RAYON FABRIC

The series of this report will be related to the influence of intentional tension differences given to the parts of the yarns during preparation and weaving of viscose rayon fabrics of plain weave, and to the fabric defects. The defects are supposed to appear through non-uniform fabric structures and uneven adsorption of dyestuff by the yarns.This report (1), deals firstly, the mechanical properties of yarns excludeing the influences which may come from the irregular properties of the yarns, and secondly, the yarn tensions in prepearing and weaving processes were actually measured. The results are as follows.(1) The difference of the creep properties between the cones was not recognized in cases of long yarn specimens, but it appears in the cases of short specimens.(2) Instantaneous elongation is proportional to the load, and when the load is taken off such elongation disappears also instantaneously.(3) The weight of the sized yarns varies according to the sizing tension, and also the composition of the sizing liquid which changes gradually during its use.(4) The irregular unwinding tension is often seen at the root of the cop.

The Adsorption of Dyestuffs by Montmorillonite

The Adsorption of Dyestuffs by Montmorillonite