Uptake Of Reactive Dyes Research Articles

Fabrication of MgO powder through ultrasound-assisted precipitation for uptake of reactive dyes from wastewater: Change in porous structure for efficient adsorption

Fabrication of MgO powder through ultrasound-assisted precipitation for uptake of reactive dyes from wastewater: Change in porous structure for efficient adsorption

Investigation of the clean patterning possibilities on cotton socks through laser technology

AbstractThe aim of this research is to reveal the effect of laser treatment at different resolutions (10, 20 and 30 dpi) and pixel times (80, 100 and 120 μs) on reactive dye uptake of cotton fabrics and the fastness values obtained. Yellowness index, Fourier Transform–infrared analysis, scanning electron microscopy analysis and bursting strength tests were applied to samples. The samples treated with laser were dyed in lighter shades than the untreated ones, with all three of the reactive dyes used in the experiments. In general, colour yield values decreased when the resolution and pixel time increased. However, no significant change was observed in washing, rubbing, light and perspiration fastness values. The possibilities of obtaining various patterns on cotton socks dyed with reactive dyes by laser treatment at different resolutions and pixel times were also investigated. According to the results, it was determined that if laser treatment was not applied to some parts of reactive dyed cotton socks, and 10 dpi 100 μs and 20 dpi 100 μs laser was applied to other parts of those socks, then it was possible to obtain patterns with different shades of the same colour on the socks. On the other hand, laser application after dyeing does not have a negative effect on fastness values. After determining the optimum conditions for the laser process, non‐see‐through tights were produced with cotton yarn on the front and polyester/elastane yarn on the back, and patterns were obtained by applying laser treatment before or after dyeing via sample scale industrial production.

Grafting of chitosan-acrylamide hybrid on the wool: Characterization, reactive dyeing, antioxidant and antibacterial studies

This study presents a new approach to enhance reactive dye uptake and functional finishing of wool yarns via simple grafting with synthesized chitosan-acrylamide (Ch-Ac) hybrid. To this, Ch-Ac was synthesized and characterized with fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Then, Ch-Ac was grafted on wool, characterized with FTIR, SEM, and weight gain analysis and dyeability with two commercial reactive dyes. Results showed that Ch-Ac treated wool could be dyed at lower temperatures (ca. 40 °C), times (ca. 30 min), and amount of reactive dye (2% owf) as compared to raw wool. Also, deeper shades not obtainable in conventional dyeing could be attained using Ch-Ac treated wool. In addition, Ch-Ac treatment imparted very good radical scavenging and excellent antibacterial activity against gram-negative (E. coli) and gram-positive (S. aureus) bacteria. Color fastness results confirmed that Ch-Ac treatment had no adverse effect on durability of dyes against washing, light, rubbing and perspiration. The results of this study clearly indicated that Ch-Ac can be used in eco-friendly functional finishing of wool with enhanced reactive dye uptake, minimized residual dye in wastewater, saving in consumption of chemicals, energy, and time of dyeing.

Role of major constituents of coconut fibres on absorption of ionic dyes

Effort was made to understand the role of major constituents of coconut fibres i.e., lignin, hemicelluloses and cellulose, on its absorption of different ionic dyes. Composition and functional groups of raw coconut fibre were changed by progressive removal of lignin, and hemicelluloses. Differently treated fibres were analyzed through FTIR, TGA, composition analysis and were dyed with anionic (acid, reactive) and cationic (basic) dyes separately. Absorption performance was assessed by surface and core colour uptake. Progressive removal of lignin resulted in reduction of uptake of anionic (acid and reactive) dyes, while increase in uptake of cationic (basic) dye. Treatment causing removal of hemicelluloses improved uptake of basic dye due to structural swelling. Increase in α-cellulose (29.9%), favours uptake of reactive dye to a higher extent. Loss of lignin occurred in case of both delignification and hemicelluloses removal treatments to the extent of 6.3% and 11.9% respectively, consequently uptake of acid dyes reduced. It may be concluded that treatment causing higher removal of hemicelluloses are beneficial and loss of lignin is disadvantageous for absorption of dyes.

The role of auxiliaries in the immersion dyeing of textile fibres: Part 7 theoretical models to describe the mechanism by which inorganic electrolytes promote reactive dye uptake on cellulosic fibres

A model is proposed to explain the manner by which the uptake of reactive dyes on cellulosic fibres is promoted by the addition of NaCl or Na2SO4 to the dyebath. The theoretical model invokes the concept of interstitial water in dyeing and suggest that increased dye uptake occurs because the added inorganic electrolyte promotes dye aggregation which reduces the solubility of the dye in the dyebath, so that the inherent preference of the highly soluble dye to favour the aqueous phase shifts towards the fibre phase. It is proposed that the same model can account for the promotion of direct dye uptake imparted by the reduction in the liquor ratio utilised for dyeing. As such, added inorganic electrolyte and reduced liquor ratio are considered to exert a combinatorial promotional effect on reactive dye uptake.

Effects of Acid/Alkali and Cellulase Enriched Mixed Enzyme Treatments on Properties of Jute-Cotton Union Furnishing Fabric

The effects of chemical pre-treatments using dilute acids [HCl, CH3COOH, HCOOH, (CH2COOH)2C(OH)COOH] and alkali (NaOH) on raw jute and jute-cotton(75:25) union fabric and the effects of specified mixed enzyme system (different proportion of mixture of cellulase, xylanase and pectinase) pretreatment on conventional 2% H2O2 bleached jute-cotton union fabric have been comparatively evaluated. Among different organic/ mineral acid pretreatments 1% HCl treatment shows higher surface brightening action than that obtained by formic acid, acetic acid and citric acid pre-treatment. All these acid pretreatment do not show desirable softening action but show varying degree of surface leaching action associated with measurable changes in K/S value, whiteness, yellowness and brightness indices. However, 10-18 % NaOH pretreatment of raw jute-cotton union fabric show appreciable softening action but is associated with higher mass loss, appreciable reduction in tenacity and surface darkening. While, 5% dilute NaOH pretreatment show somewhat less softening action, but exhibit lower mass loss, lower surface darkening and lower reduction in tenacity which may be practically useful in imparting desirable softness in jute-cotton union fabric. Treatment with specified cellulase enriched mixed enzyme system (175 unit/ml of cellulase, 96 unit/ml of xylanase and 136 unit/ml of pectinase) on either 1 or 5% NaOH pretreated or conventional 2%H2O2 bleached jute-cotton union fabric renders a moderate degree of softening action and surface smoothening with overall good balance in important textile related properties. However, higher degree of softening action may be achieved, if the said mixed enzyme treatment is carried out after both sequential pretreatments i.e. 5% NaOH pretreatment followed by conventional H2O2 bleaching at the cost of higher weight loss and reduction in tenacity. Studies on Dyeability of such chemically treated jute-cotton union fabric reveals that NaOH pretreatment show an increasing trend for acid dye uptake and reactive dye uptake, while all the dilute acid pretreatments show an increasing trend of basic dye uptake in general.

Effect of liquid ammonia treatment on the pore structure of mercerized cotton and its uptake of reactive dyes

Structural changes in mercerized cotton by liquid ammonia (LA) treatment were investigated and correlated with changes in dyeability of cotton fabrics with reactive dyes. The pore structures of mercerized cotton and mercerized-liquid ammonia (M-LA) treated cotton were characterized by inverse size exclusion chromatography (ISEC). Results showed that when the mercerized cotton was subjected to LA treatment, cumulative accessible volume of smaller pores (e.g., 25.2 Å) increased, whereas that of the larger pores (e.g., 56.7 Å) decreased. These results might be related to the changes in the amorphous region of cotton fiber. The decrease in crystallinity of cotton fiber would increase accessible volume of smaller pores. The larger pores might be compressed by extrusion during swelling of microfibrils or elementary fibrils in water. The change in dyeability of fabrics with reactive dyes of various molecular weights could be rationalized using the observed changes in pore structure. Results also showed that ISEC was more suitable than the method employing Chrastil's diffusion equation for analyzing the pore structure of cotton fiber.

SIGNIFICANCE OF CHITOSAN TO IMPROVE THE SUBSTANTIVITY OF REACTIVE DYES

Chitosan (polysaccharide) is used for cationization of cotton and to increase the uptake of reactive dye by the cationized cotton. Four different concentration of chitosan (0.5, 1.0, 1.5 and 2.0%) were applied for 0.5 and 4.0% shades of C.I. Reactive Red and C.I. Reactive Yellow dye, respectively. Different properties e.g. K/S value, washing fastness, light fastness and rubbing fastness of the dyed cotton (untreated and treated with chitosan) were recorded for comparison. The K/S values of chitosan treated fabrics (6.1-13.9 and 18.3-22.8 for both dye shades, respectively) were considerably better than untreated fabric (4.7-5.3 and 16.8-17.0). The results of present study clearly demonstrated that the use of chitosan as an exhausting agent not only reduced the amount of dye for dyeing the cotton fabric but also improved the washing and rubbing fastness properties. The present study further demonstrated that the use of chitosan in textile industry can minimize the dyeing cost, effluent treatment cost and other auxiliary utilization.

Studies on Dyeing Process Variables for Salt Free Reactive Dyeing of Glycine Modified Cationized Cotton Muslin Fabric

Bleached cotton muslin fabric with or without pre-oxidized with NaIO4 (oxy-cotton) was chemically modified with glycine (amino acid) by pad dry calendar process to investigate the changes in textile properties and its dyeability with reactive dye. This glycine modified cotton incorporates new functional groups producing –NH3+ or –C=NH+ -ion (cationic groups) in acid bath to obtain cationized cotton making it amenable to a newer route of salt free reactive dyeing in acid bath. In the present work the process variables of reactive dyeing in the salt free acid bath for dyeing of amine (glycine) modified cationized cotton were studied and optimized. The present study also includes thorough investigation of changes in important textile related properties and dyeability with reactive dye after such chemical modifications. Between oxidized and unoxidized cotton muslin fabric, unoxidized cotton fabric shows better reactive dye uptake in both conventional alkaline bath dyeing and nonconventional salt free acid bath dyeing particularly for high exhaustion class of reactive dye with acceptable level of colour fastness and overall balance of other textile related properties. Moreover, application of dye fixing agent further improves surface colour depth (K/S) of the glycine treated cotton fabric for HE brand of reactive dyes. Corresponding reaction mechanisms for such modifications were supported by FTIR spectroscopy. Finally unoxidized cotton and pre-oxidized cotton further treated with glycine (amino acid) provide a new route of acid bath salt free reactive dyeing showing much higher dye uptake and higher degree of surface cover with amino acid residue anchored to modified cotton.

English

    Biosorption is an alternative process for uptake of reactive dyes from aqueous solution. In the present study, the biosorption of  reactive black 5 (RB 5) from aqueous solution was investigated by using loquat (Eriobotrya japonica) seed biosorbent in a  batch adsorption technique as a function of contact time (0.5 min to 3 h), initial dye concentration (50 to 200 mg/L), biosorbent dose (5 to 30 g/L) and pH (1.5 to 5.5). The experimental data showed that the optimum pH for efficient biosorption of RB 5 was 2.5. The data were analyzed on the basis of Lagergren pseudo-first-order, pseudo-second-order, Elovich equation and Weber-Morris kinetic models tested. The results suggested that the pseudo-second-order model (R>0.999) was the best choice among all the kinetic models to describe the biosorption behavior of RB 5 onto the biosorbent. The equilibrium data were evaluated by using Langmuir and Freundlich isotherms and the Langmuir isotherm was found to provide the best correlation of the experimental data. Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) changes indicated that the biosorption of RB 5 onto loquat seed biosorbent was feasible, spontaneous and endothermic. The results revealed that loquat seed biosorbent could be used as biosorbent for the treatment of wastewater containing RB 5. Key words: Biosorption, isotherm, loquat seed, reactive black 5, thermodynamic. &nbsp

Ultrasound for wool dyeing and finishing

The effects of ultrasound at 35–39 kHz on several wool dyeing and finishing processes have been investigated as a way of reducing environmental impact. Ultrasound improved the effectiveness of cleaning scoured wool in water and to a lesser extent in water-nonionic surfactant. Scanning electron microscopy did not indicate any surface damage. Fluorescence microscopy revealed increased levels of sulphydryl groups on the wool surface suggesting ultrasound caused the removal of thioester-bound lipids. Ultrasound pre-treatment increased the effectiveness of subsequent oxidative–reductive bleaching, but had no effect on the uptake of acid levelling and acid milling dyes. The pre-treatment retarded the uptake of reactive dye, possibly by increasing the crystallinity of the fibre or removing surface bound lipids. Ultrasound did not improve dyeing under conditions that are currently used in industry, but did show potential to reduce the chemical and energy requirements of dyeing wool with reactive and acid milling dyes, but not acid levelling dyes.

Biosorption of RBBR by Trichoderma harzianum WL1 in stirred tank and fluidized bed reactor models

A lab scale stirred tank and fluidized bed reactor models were employed for the removal of RBBR from aqueous solution using autoclaved biomass of Trichoderma harzianum WL1. In batch mode, the effect of contact time and initial dye concentration, adsorbent dosage was investigated and optimal experimental conditions were ascertained. Dye decolorization experiments were carried out at pH 2.0, since the reactive dye uptake was favored at higher acidic environment. Equilibrium time was attained at 150 and 135 min in stirred tank and fluidized bed reactors respectively for the dye concentrations of 25–100 mg/L. The maximum percent color removal at equilibrium was observed from stirred tank reactor as 89.3–71.4% (25–100 mg/L). The adsorbent dosage of 1.5–2.0 g/50 mL was found to be optimum for increased dye uptake. The experimental data were analyzed by Langmuir and Freundlich isotherms and adsorption kinetics were determined. Both the Langmuir and Freundlich isotherms could describe the adsorption equilibrium of the adsorption system. The adsorption capacity ( Q 0) of 4.59 and 4.51 mg/g was recorded for RBBR removal by stirred and fluidized bed reactors, respectively. Kinetic studies showed that dye adsorption onto fungal biomass fitted well with second-order kinetic model. Stirred tank reactor showed a better adsorption capacity than fluidized bed reactor.

Effects of Leveling Agent on the Uptake of Reactive Dyes by Untreated and Plasma-treated Wool

Atmospheric-pressure plasma treatment of wool fabric produced a significantly higher level of adsorbed fiber-reactive dye when applied at 50 °C (pH 3.0—6.0) in the absence of any organic leveling agent. In addition, color yields indicated that dye was more uniformly adsorbed by the plasma-treated fabric compared with the untreated material. When untreated fabric was dyed in the presence of a leveling agent (Albegal B), the extent and levelness of dye sorption were enhanced. These enhancements were, however, relatively small on the plasma-treated wool compared with those on untreated wool. A ‘surface’ mechanism, similar to that proposed when plasma-treated wool is dyed in the absence of leveling agent, can explain the leveling ability of Albegal B under adsorption conditions. Increasing the dyebath temperature to 90 °C resulted in dye penetration of the fibers. Under these conditions, any enhancements of dye uptake produced by the plasma treatment, as well as the use of Albegal B, were relatively small, in contrast to the behavior at 50 °C. Improvements in the uniformity of dye sorption observed at 50 °C were, however, maintained at the higher temperature. It is concluded that the inability of reactive dyes to migrate (and so promote leveling and uniformity) once they have reacted with the fiber, means that differences in the uniformity of dye sorbed at 50 °C are still apparent at equilibrium.

Different binding mechanisms in biosorption of reactive dyes according to their reactivity

Various binding mechanisms for the uptake of reactive dyes by the protonated waste biomass of Corynebacterium glutamicum were investigated. As model reactive dyes, Reactive Blue 4 (RB 4), Reactive Orange 16 (RO 16) and Reactive Yellow 2 (RY 2) were used in this study. The solution pH strongly influenced the sorption capacity and the binding mechanisms of reactive dyes by C. glutamicum. At acidic pH, the electrostatic interaction was found to be a major binding mechanism. The maximum uptakes of RY 2, RO 16 and RB 4 at pH 2 were estimated to be 155.0 ± 14.1, 156.6 ± 6.7 and 184.9 ± 16.4 mg/g, respectively. Under alkaline conditions, the binding mechanisms were quite different according to the reactivity of reactive dyes. It was found that chemical bonding existed between the biomass surface and dye molecules under basic pH conditions.

Biocatalytic surface modification of knitted fabrics made of poly (ethylene terephthalate) with hydrolytic enzymes from Thermobifida fusca KW3b

Knitted fabrics made from poly(ethylene terephthalate) fibres were treated with an enzyme preparation from Thermobifida fusca KW3b showing hydrolytic activity on p-nitrophenyl butyrate. The fabrics were also treated with NaOH and the results were compared. Both enzyme- and alkaline-treated fabrics showed an increase in reactive dye uptake, vertical wicking height and water absorption capacity of the fabrics indicating an increased surface hydrophilicity. However, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS) did not give conclusive results on the presence of newly introduced hydrophilic groups on the surface of the fibres. Analysis of the enzyme-treated poly(ethylene terephthalate) fibres by scanning electron microscopy (SEM) and by atomic force microscopy (AFM) indicated an increase in surface roughness of the fibres, which may contribute to the observed increased hydrophilicity of the PET fabrics. However, much longer treatment times (24 h) were required to obtain these effects with the enzymes compared to the chemical treatment (1 h).

The sorption of a syntan on nylon and its resist effectiveness towards reactive dyes

The sorption behavior of a commercial syntan on nylon and its resist effectiveness towards the uptake of reactive dyes on both nylon and nylon/cotton blend fabrics were investigated. The sorption isotherms of the syntan on nylon at pH 4 fitted a dual sorption mechanism consisting of partition and Langmuir type models. Whereas Langmuir sorption saturation was little influenced by temperature in the range of 50–80 °C, partition coefficients and Langmuir affinity constants increased with increasing temperature, indicating that syntan sorption was endothermic. The ability of the syntan to resist the uptake of reactive dyes was greatly influenced by the nature of the dye and the temperature of syntan application; the observed increase in resist effectiveness that accompanied an increase in the temperature of syntan application can be attributed to a corresponding larger uptake of syntan and greater extent of diffusion of the syntan within the nylon substrate, together with a lower extent of syntan desorption during reactive dyeing.

Color Removal of Reactive Dyes from Water by Clinoptilolite

The adsorption of reactive dyes on Gordes (Turkey) clinoptilolite was investigated by a series of batch and column adsorption experiments. Three reactive dyes (Everzol Black, Everzol Red, Everzol Yellow) were used in laboratory studies. Synthetic wastewaters were used and the ability of natural zeolite (clinoptilolite) and their modified form were examined. The adsorption results, in batch and column reactor, indicate that natural zeolite have limited adsorption capacities of the reactive dyes but are substantially improved upon modifying their surfaces with quaternary amines (HTAB). The degree of hydrophilicity is found to play an important role in the uptake of reactive dyes.

Equilibrium studies on the adsorption of reactive azo dyes into zeolite

Zeolite was used as a low-cost adsorbent to evaluate its ability to remove color from textile effluents. The zeolit (clinoptilolite) used in this study is a natural clay mineral from the Gbrdes region of Turkey. The adsorption of reactive dyes into zeolite was investigated by a series of batch adsorption experiments. Three reactive dyes (Everzol Black, Everzol Red, Everzol Yellow) were used in laboratory studies. Adsorption test were carried out as a function of solids concentration, conditioning time and dye concentration. The degree of hydrophilicity was found to play an important role in the uptake of reactive dyes. The adsorption results indicated that natural zeolite has a limited adsorption capacity for reactive dyes but can be distinctly improved by modifying its surfaces with quaternary amines. A comparison of natural and modified zeolites at 5% solids concentration indicated that, while the adsorption densities of dyes with natural zeolite yielded negative or slightly positive values, those with modified zeolite gave adsorption densities in the range of 2.9 to 7.6 mg/g.

Use of chitosan to improve dyeability of DP-finished cotton (II)

Chitosan was used to improve the dyeability of DP-finished cotton. Cotton fabric was treated with a mixture of chitosan, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone (DHDMI), and catalyst in a one-step process. To investigate the effect of molecular weight of chitosan on the dyeability of treated fabrics, six chitosan samples of different molecular weights were prepared by depolymerization with sodium nitrite; 185,300, 73,200, 59,000, 21,000, 14,000, and 3,800, respectively. Chitosan improves dye uptake of direct and acid dyes considerably, and the dye uptake increases with the increase of the molecular weight of chitosan. Reactive dye uptake increases slightly in alkaline condition as the molecular weight of chitosan decreases. Higher dye uptake is obtained in acidic condition than in alkaline condition. Chitosan treatment has no discernable effect on the colorfastness to washing, but decreases the colorfastness to wet crocking by about half a point. And chitosan affects other properties of treated fabric; lower wrinkle recovery, stiffer handle, and higher breaking strength as the molecular weight of chitosan increases. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1515–1521, 1998

Interrelations between the fibre structure and the reactive dyeing properties of NaOH-treated cotton fibres

Changes of fibre structure and the fixation of C.I. Reactive Blue 52 in cotton subjected to different kinds of NaOH-treatments have been studied. The fibre structure was characterized by measurements of the pore volume, pore surface and pore size distribution using a solute exclusion technique. The results revealed that for the reactive dye uptake the pore region with pore diameters of 20–50 Å may have a special importance.