Dual-mode adsorption of cochineal natural dye on wool fibers: Kinetic, equilibrium, and thermodynamic studies (original) (raw)
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8 Physico-chemical Aspects of Wool Dyeing: Adsorption, Kinetics and Thermodynamics
industrial sectors in terms of environmental protection levels, comfort, and health. In order to manipulate the process of natural dyeing efficiently and to get maximum color yield in economical way, it is essential to develop knowledge based on dye chemistry, various aspects of dyeing process variables, rate of dyeing and chemical kinetics of dyeing for different dyes and fiber combinations. In this chapter, physical and chemical aspects of wool dyeing processes were discussed with the focus on the effect of chemical modifications of textile materials on the adsorption characteristics. A comparative analysis of various textile substrate surfaces were discussed in relevance to the dyeing process parameters responsible for dye stickiness towards textile materials.
In the present investigation adsorption studies, colorimetric, and emission characteristics of Adhatoda vasica natural dye onto woolen yarn were investigated. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH, with maximum adsorption at pH 3. Pseudo-first order, Pseudo-second order, Elvoich, and Intraparticle diffusion equations were employed to investigate adsorption rates. Pseudo-second order model provided best fit to the experimental data with activation energy of 69.039 kJ mol À1 indicating chemisorption. The equilibrium adsorption data were fitted to Langmuir, Freundlich, Redlich-Peterson, and Hill isotherm models. Redlich-Peterson and Hill isotherm models agreed well with the experimental data having high regression coefficients and least standard deviations for dyeing temperatures of 50, 70 and 90 C with dye concentration varying from 0.5-20% (o.w.f). A comparative adsorption investigation on silk fiber was presented to understand the better efficiency of woolen yarn. Colorimetric properties and fluorescence characteristics of dyed woolen yarn mordanted with metal salts were generally dependent on chemical nature of mordants and woolmordant-dye complex forming ability.
Coloration Technology, 2018
The adsorption behaviour of the natural dye cochineal on polyamide 66 was studied at different pH values. The thermodynamic and kinetic parameters such as standard affinity (ÀDl˚), changes in enthalpy (DH˚) and entropy (DS˚), diffusion coefficient and activation energy of the diffusion, were determined for pH values of 3 and 6. Results indicated that the experimental data fitted appropriately with the Nernst isotherm. Furthermore, the partitioning ratio and ÀDl˚decreased significantly with increasing temperature, and it was revealed that the adsorption of cochineal onto polyamide was an exothermic process. The ÀDl˚value of polyamide dyed at pH 3 was higher than that dyed at pH 6. This is related to higher numbers of electrostatic and nonelectrostatic interactions between cochineal and polyamide at pH 3, whereas at pH 6 non-electrostatic hydrophobic interactions between cochineal and polyamide are dominant. At pH 6 comparatively higher negative values for DH˚and DS˚were obtained. The diffusion coefficient increased with rises in temperature. The polyamide dyed at pH 3 had a higher diffusion coefficient at every temperature than the polyamide dyed at pH 6. The dyeing rate for polyamide at pH 3 was higher than at pH 6 and reached equilibrium in a shorter time. Furthermore, a lower activation energy of diffusion was obtained at pH 3 compared to pH 6.
Adsorption of Methylene Blue from aqueous Solution on the Surface of Wool Fiber and Cotton Fiber
Adsorption of dye methylene blue from aqueous solution on the surface of sheep wool and cotton fibers was accomplished under the optimize conditions of temperature, concentration, pH, stay time duration and quantity of adsorbent. Spectrometric technique was used for the measurements of concentration of dye before and after adsorption. The percentage removal and distribution constant (K D ) values for the removal of of methylene blue were also calculated. The values of % adsorption data for methylene blue -sheep wool system show better adsorption capacity as compared to methylene blue -cotton fiber system. The applicability of Langmuir and Freundlich adsorption isotherm equations for the present system was also tested. The experimental data are fitted to the Langmuir and Freundlich isotherm equations. The values of their corresponding constants were determined from the slope and intercepts of their respective plots. Thermodynamic parameters like ΔG o , ΔH o and ΔS o were calculated on the basis of Langmuir constant K. The methylene blue -sheep wool system show non spontaneous and exothermic behavior, while methylene blue -cotton fiber system show spontaneous and endothermic behavior. The results of these investigations suggested that natural adsorbents can be utilized as adsorbent materials, because of their selectivities for the removal of dyes. @JASEM
Adsorption of Textile Dyes Using Agave Americana (L.) Fibres: Equilibrium and Kinetics Modelling
Adsorption Science & Technology, 2007
This study was carried out to examine the potential of Agave americana fibres (AAF) for the treatment of wastewater contaminated with dyes. The batch mode adsorption of two dyes, viz. Sumfixe Supra Red (SSR) and Alpacelle Lumiere Brown (ALB), by AAF was investigated at different pH values, temperatures and initial dye concentrations. The highest dye adsorption capacities at 30°C were attained at pH 2.0 for SSR and at pH 2.5 for ALB. In both cases, an increase in temperature increased the velocity of the reaction. The maximum amounts of dyes desorbed were at basic pH values. To compare our results with studies on other biomaterials, the adsorption isotherms and kinetic data were analysed employing the usual models (Freundlich, Langmuir and Temkin isotherms and first- and second-order kinetics). Conventional analysis indicated that the kinetics of the processes were closer to pseudo-second order rather than first order. The data were also modelled with a new method of analysis based o...
Sorption of acid violet 17 and direct red 80 dyes on cotton fiber from aqueous solutions
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007
Sorption of acid violet 17 and direct red 80 azo dyes on locally available cotton fiber from aqueous solution has been investigated as a function of shaking time, pH, dyes concentration and temperature. Maximum sorption of acid violet 17 and direct red 80 on cotton fiber was achieved within 30 and 60 min of shaking time and at pH 8 and 8.5, respectively. Sorption isotherms for acid violet 17 and direct red 80 dyes were obtained at pH 8 and 8.5, respectively, at constant temperature. These isotherms are L-3 types having small plateaus, and the upward trends in sorption capacity after the plateaus points towards the possibility of multilayer formation. The increasing temperature induces a negative effect on the sorption of acid violet 17 (exothermic) and positive effect on the sorption of directs red 80 (endothermic). Isosteric heat of adsorption (q st ) have also been calculated at different surface coverage indicating that cotton fiber possessed heterogeneous surface with site of different activity. The results also indicate that initial sorption, whether chemical or physical means, occurs first on the most active sites and then on the sites of lesser activity.
Adsorption interaction between natural adsorbents and textile dyes in aqueous solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2005
Agricultural wastes from maize culture fields were prepared and activated yielding the natural absorbents designated as SOMAP, SOMAP1, SOMAP2, HELAP, HELAP1, SAGAP, and SAGAP1. The samples were further characterized using microscopy, FTIR spectroscopy, titration, and adsorption from solution. The dry and wet methods of analysis confirmed the presence of functional groups (hydroxyl, carboxylic, phenolic, and lactonic) in the bulk and on the surface, respectively. Each prepared solid sample was tested for adsorption ability using aqueous dye solutions of basic blue 41 (BB41), acid blue 74 (AB74), and reactive black 5 (RB5). The adsorption affinity decreased according to BB41 > AB74 > RB5. For BB41 the relative adsorbent saturation followed the series: SOMAP2 < SOMAP1 < SOMAP, HELAP < HELAP1 and SAGAP < SAGAP1. Adsorption equilibrium concentrations were followed by HPLC with diode array detection. The equilibrium data fitted well with both Langmuir and Freundlich models of adsorption. The values of the Freundlich exponent 1/n correlated with the variance of the group distribution curves. The monolayer capacity of all studied adsorbents using the basic dye BB41 correlated acceptably with the corresponding amount of total acid groups on the adsorbent surface.
Adsorption, Kinetics and Thermodynamics of Reactive Dyes on Chitosan Treated Cotton Fabric
Textile & Leather Review
The adsorption performance, kinetics, and thermodynamic parameters of reactive dyes on chitosan-treated cotton fabric are described in this research. The batch experiment was carried out to investigate the influence of pH, time, temperature, dye concentration, and material to liquid ratio of Remazol Red RR and Remazol Yellow RR, two widely used reactive dyes. The adsorption of red and yellow dyes was observed at λmax 517 and 419 nm respectively. For both Remazol Red RR and Remazol Yellow RR reactive dyes with starting dye concentrations of 0.0667 and 40 mg/L, the greatest dye adsorption was reported at pH 11 (0.0009 and 0.1284 mg/g) and pH 4 (0.0004 and 0.1038 mg/g). The adsorption performance was investigated using the Langmuir and Freundlich isotherms. The adsorption behaviours of the two reactive dyes closely matched to the Langmuir adsorption isotherm (R2>0.98) than Freundlich isotherm (R2>0.92). The pseudo-second-order kinetic model (R2>0.99) was followed by the dyeing...
TEKSTILEC
The removal of textile reactive dye from an aqueous solution on a new adsorbent prepared from waste cotton knitted fabric was investigated in this study. Waste cotton textile, used for the production of adsorbents, is a by-product of the cutting of stacked parts of cotton knitwear planned for the production of women’s T-shirts. The degree of efficiency of a paper pattern determines the amount of collected waste. The qualitative and quantitative characterization of the new adsorbent showed carbon and oxygen to be dominant in the chemical composition. A longer contact time means a greater amount of dye on the adsorbent, i.e. the dye concentration in the solution decreases with the duration of the adsorption process. The percentage of removed dye decreases with an increase in the initial dye concentration in the solution. However, the actual amount of adsorbed dye increases as the initial dye concentration increases. The results for equilibrium adsorption show that the Langmuir isother...
Synthesis and study of adsorption isotherms of a tris-azo direct dye on cotton fibres
The paper discusses the synthesis and characterization ofa tris-azo direct dye containing 4, 4'-diaminobenzanilide as middle component, and 8-amino-l-naphthol-3, 6-disulfonic acid (H acid) monocoupled with aniline, respectively m-phenylendiamine as coupling components. The synthesized dye was analyzed by means ofVIS spectroscopy and thin layer chromatography (TLC). Colouristic and fastness properties ofthe synthesized dye were also determined. Study of the adsorption isotherms for this dye on cotton fibre was performed at 60o, 860 and 96o. The experimental data obtained from the dyeing process agreed with the standard Nernst, Freundlich and Langmuir isotherms, and with the general multimodal adsorption model, as well. The best statistical results were obtained with the classical Langmuir model. Thermodynamic parameters (equilibrium constants, saturation concentration values) were derived by regression analysis.