Half Dyeing Time Research Articles

Dyeing kinetics and thermodynamics of mono-chlorotriazine reactive dye in recycled wastewater

Purpose This study aims to elucidate the dyeing kinetics and thermodynamic relationships of CI Reactive Red 24 (RR24) on cotton fabrics, achieve the recycling of inorganic salts and water resources and obtain comprehensive data on color parameters, fastness and other characteristics of fabrics dyed with the recycled dyeing residual wastewater. Design/methodology/approach The dyeing wastewater obtained through advanced oxidation technology was used as a medium for dyeing cotton fabrics with RR24. The absorbance value of the dyeing residue served as an evaluation index, and the relevant kinetic and thermodynamic parameters were calculated based on this absorbance. The color parameters and fastness of the fabric samples were measured to compare the performance of different dyeing media. Findings Dyeing cotton with RR24 in both media follows pseudo-second-order kinetics. When dyeing with wastewater media, the dye adsorption in the first 45 min increased by 0.082–1.29 g/kg compared with conventional dyeing. Furthermore, the half-dyeing time was shortened by 4.19–11.99 min and the equilibrium adsorption amount was reduced by 0.277–0.302 g/kg. The adsorption of RR24 on cotton fabrics conformed to the Freundlich model. Fabrics dyed using recycled wastewater exhibit a deeper color, with reduced red light and enhanced blue light, resulting in an overall deeper apparent color. Originality/value These dyeing kinetics and thermodynamic properties are beneficial for comprehending and interpreting the dyeing performance and behavior of reactive dyes in dyeing wastewater. They lay a theoretical foundation for the treatment and recycling of dyeing wastewater.

Cleaner reactive dyeing with the recycled dyeing wastewater

In order to recycle water and inorganic salts, sodium persulphate (SPS) was used to degrade the C.I. Reactive Red 195 (RR195) dyeing wastewater. The thermodynamic and kinetic relationships of RR195 dyeing in cleaner and conventional dyeing processes were analyzed and compared. The feasibility of the one-bath cyclic dyeing in the recycled dyeing wastewater was confirmed through the properties of dye utilization, color parameters and energy conservation. The appropriate conditions were 0.3 g/L of SPS and treatment at 95 °C for 30 min, which resulted in a decolorization rate of 99.7% for the dyeing wastewater, mainly due to the action of radical sulfate. When cotton fabric was dyed with the cleaner dyeing, the kinetic was pseudo-second-order and the thermodynamic was Freundlich adsorption. There was a 47.5% reduction in half dyeing time, a greater diffusion coefficient and standard affinity, and lower entropy and enthalpy values when dyeing in reused wastewater. Cotton fabrics were dyed with the proposed cleaner dyeing process, which reduced the amount of water and inorganic salt by 95.8% and 89.8%, respectively. The total organic carbon (TOC), biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) were 53.6%, 69.8% and 42.6% lower than the conventional dyeing process, respectively. The recommended technology not only reduces the amount of dyeing wastewater but also enables the recycling of inorganic salts and water, which makes great progress in the textile industry.

Adsorption and dyeing properties of acid dye on bio-based polyamide 11 fibers

The dyeing mechanism of bio-based polyamide 11 fibers with acid dyes was explored in order to provide a theoretical foundation for the dyeing properties of polyamide 11 fibers. The surface morphology and diameters of polyamide 11 fibers and polyamide 6 fibers were compared. Both polyamide 11 fibers and polyamide 6 fibers were dyed with acid dye Isolan blue NHF-S, and the effects of the initial dye concentration, pH values, dyeing temperature and time on the dyeing properties were investigated. The effects of the dyeing kinetics and thermodynamic model of Isolan blue NHF-S on polyamide 11 fibers were analyzed, and the corresponding parameters were calculated. It was found that the dyeing properties of polyamide 11 fibers were not comparable to those of polyamide 6 fibers, while the washing and rubbing fastness were more or less the same. The dyeing mechanism of Isolan blue NHF-S on polyamide 11 was a combination of localized and non-localized adsorption, which conformed to the pseudo-second-order kinetic model and the Redlich–Peterson thermodynamic model. Increasing dyeing temperature could shorten the half-dyeing time and improve the average diffusion coefficient and affinity between the dye and polyamide 11 fibers.

Adsorption of Reactive Red 120 in Decamethyl-Cyclopentasiloxane Non-Aqueous Dyeing System

Traditional dyeing usually consumes a significant amount of water and salts, thus causing environmental pollution. Salt-free and low-water dyeing has become an important research direction in the cotton fabric dyeing industry. The non-aqueous media dyeing technology, using decamethylcyclopentasiloxane (D5) as the dyeing medium, has achieved energy saving and emission reduction in this industry. To investigate the influence of inorganic salts on the dyeing properties of reactive dyes in a non-aqueous medium dyeing system, the adsorption kinetics and level dyeing property of C.I. Reactive Red 120 were investigated at various concentrations of sodium sulfate. When no salts were included in the siloxane non-aqueous dyeing system, 80% of the reactive dye could diffuse onto the cotton fabric surface after 10 min. However, if 13% salts were added during dyeing, 87% of the reactive dye could diffuse to cotton fabric surface over the same amount of time. Moreover, the adsorption rate of dye was increased from 3.85 mg/g·min to 5.04 mg/g·min when the quantity of salts was increased from 0% to 13%. However, the concentration of sodium sulfate had minimal effect on the color depth of the dyed fabric and the final uptake of dye. But, when the concentration of sodium sulfate was significant, the level dyeing property of the dye became poor as the Sγ(λ) value was increased from 0.020 to 0.042. The adsorption kinetic of C.I. Reactive Red 120 in D5 dyeing solution may be best described by the pseudo-second-order kinetic model. As the sodium sulfate concentration increases, the half-dyeing time gradually decreases and the adsorption rate of dye increases. The repulsive force between the dye and the cotton fiber was lowered by the addition of sodium sulfate. Consequently, in the D5 dyeing system, the level dyeing property of reactive dye may be affected by the adsorption rate. Therefore, the formula of reactive dyes that do not contain salts can be applied successfully in non-aqueous dyeing systems.

Physicochemical Behavior of Superfine Wool Powder Dyed with Reactive Dye

ABSTRACT Superfine wool powder is obtained from waste wool fiber by physical grinding. Its physicochemical properties are different from those of wool fiber, and it is widely used in industry. In order to clarify the dyeing behavior of wool powder, C. I. Reactive Yellow 145 dye was used to dye wool powder, and the adsorption kinetics and thermodynamics were systematically studied in this work. The adsorption kinetics of reactive dye on wool powder was found to adhere to a pseudo-second-order kinetic model. At 60, 80 and 95°C, the half-dyeing time (t 1/2) and diffusion coefficient were 2.37, 1.56 and 1.00 min, and 0.2045, 0.1611 and 0.1368 cm2·min−1, respectively. And the diffusion activation energy was −11.82 kJ·mol−1. A Langmuir-type adsorption isotherm was obtained. At 60, 80 and 95°C, the standard affinity was 18.17, 20.06 and 20.82 kJ·mol−1, respectively. And the dyeing enthalpy change and dyeing entropy change were 7.27 kJ·mol−1 and 0.077 kJ·mol−1·K−1, respectively. In addition, the specific surface area, morphology and dyeing properties of wool fiber were compared. Through the study on the dyeing physicochemical properties of wool powder, it provides a theoretical basis for people to understand and use wool powder.

Investigation on dyeing mechanism of modified cotton fiber.

Cotton fabrics have been chemically modified with two cationic compounds. They were 3-chloro-2-hydroxypropyltrimethylammonium chloride and the copolymer of dimethyl diallyl ammonium chloride and allyl glycidyl ether, respectively. Under the conditions of no inorganic salt, two modified cotton fabrics were dyed with reactive dyes. The dyeing mechanism of two modified cotton fabrics was investigated in comparison with traditional dyeing of untreated cotton fabrics. It involved the adsorption type, adsorption thermodynamics, and adsorption kinetics between reactive dyes and modified cotton fabrics in the dyeing process. The color-fixing process of modified cotton fibers was also studied in detail. The results showed that there were obvious distinctions between the salt-free dyeing mechanism of modified cotton fabrics and traditional dyeing of untreated cotton fabrics. The adsorption isotherm model of the two modified cotton fabrics conformed to the Langmuir-model. The kinetic model of two modified cotton fabrics conformed to the pseudo-second-order kinetic model. The adsorption of modified cotton fabrics was an endothermic process. The adsorption of unmodified cotton fabrics was an exothermic process. These will serve as a theoretical basis of the industrial production of salt-free dyeing of modified cotton fiber.

Absorption kinetics and thermodynamics of cationic dyeing for poly(ethylene terephthalate) copolyester modified by 2,2-dimethyl-1,3-propylene glycol (NPG)

The copoly(ethylene terephthalate) (ENCDP) were successfully prepared with 2,2-sodium-5-sulfo-bis-(hydroxyethyl)-isophthalate (SIPE), poly(ethylene glycol) (PEG) and 2,2-dimethyl-1,3-propylene glycol (NPG), named as cationic dyeable polyester. The dyeing properties consisted of adsorption kinetics and thermodynamics of cationic blue X-BL on the ENCDP fabric were investigated. The T-Vickerstaff hyperbolic adsorption model could be used to explain the adsorption kinetics and predict the equilibrium rate constant k, equilibrium dye sorption capacity (C∞), the half dyeing time (t1/2) and diffusion coefficient (D) at different temperatures. According to the adsorption activation energy (Ea)> 40KJ/mol, it is judged that the isotherm adsorption conforms to the langmuir isotherm and possessed the higher correlation. Moreover, the determined thermodynamic parameters including the positive value of adsorption affinity (-Δµ°) and enthalpy change (ΔH°) showed that the dye adsorption onto ENCDP was a chemisorption process of spontaneous and endothermic.

Adsorption kinetic and mechanism of reactive dye on cotton yarns with different wettability in siloxane non-aqueous medium

Adsorption kinetic of reactive dye (red 195 and blue 19) on cotton yarns with different wettability was compared via a pseudo-first-order kinetic model and a pseudo-second-order kinetic model in siloxane non-aqueous dyeing system and traditional water base. The results shown that the adsorption kinetic of these two dyes could be described by the pseudo-second-order kinetic model. In siloxane non-aqueous dyeing system, the dyeing rate of dye was increased with the increase of yarn wettability, but the final uptake of dye was kept unchanged (close to 20 mg/g). Most remarkably, the final uptake of dye was more than doubled in the siloxane medium comparing with the traditional water bath dyeing, while the half-dyeing time of dye was decreased significantly. Although dyeing rates were increased with temperature for both systems, the final uptake of dyes remained stable with the temperature increase in the siloxane non-aqueous dyeing system but was significantly decreased in traditional water bath. The adsorption mechanism was also discussed, and the medium effects were considered to be important factors in the adsorption of reactive dye. Since reactive dye is completely non-miscible with siloxane medium, but has strong affinity to cotton yarn, almost all of reactive dye will be transferred to yarn surface under mechanical force. As a result, siloxane medium provides an innovative approach to increase dye uptake under a low dyeing temperature (20 °C). Furthermore, reactive dyeing in siloxane non-aqueous system only need a small amount of water without using any salt, and reduce dyeing waste-water emission.

Dyeing of Cochineal Natural Dye on Cotton Fabrics Treated with Oxidant and Chitosan

ABSTRACT Cotton fabrics were modified through an oxidation of the fabric with hydrogen peroxide followed by chitosan to improve their dyeability toward cochineal natural dye. Comprehensive studies were conducted on these fabrics to select chitosan modification process and assess their dyeability to cochineal in the ethanol-water system. The scanning electron micrograph showed the chitosan was deposited on the surface of cotton fiber. The infrared spectrum revealed the interaction between chitosan and cellulose further. Thermal gravity analysis showed the treatment produced little effect on the thermal stability of the cotton fabric. Treating cotton with 15 g/L chitosan and baking at 130°C offered higher cochineal adsorption. Dyeing with increased time and at elevated temperatures resulted in higher dye uptake. The ratio of ethanol and water had obvious effects on solution polarity and when the proportion of ethanol and water was 9:1, cochineal adsorption reached maximum value. pH value had complex effects on K/S value and pH 7 yielded the highest color strength. Dyeing kinetics curves indicated that with the increase of the dyeing temperature, dye diffusion coefficient increased and half dyeing time decreased. The washing and rubbing fastness of the treated cotton fabrics were all improved and rated above grade 3.

Kinetic Investigations on Dyeing of Different Polyester Fabrics Using Microwave Irradiation

There are several factors affecting physical and mechanical properties of the woven polyester fabrics, from these factors different weave constructions. The goal of this research is to study the effect of using different polyester fabric constructions on dyeing process via microwave irradiation. The resulted change in dye absorption, dyeing time and dyeing temperature were investigated. The fabric characteristics; namely tensile strength, elongation, and color fastness properties were also studied. The percentage dye exhaustion, dye fixation ratio and total dye fixation were evaluated. Dyeing rate constant, half dyeing time, activation energy and dye affinity of the different polyester fabric structures were calculated. The results this investigation proved that use of microwave irradiation brings about improvement in the quality of dyed fabric uniformity and color fastness properties. The woven polyester fabrics dyed with disperse dye and subjected to microwave irradiation for 50 min. at 100°C at different dye concentration increased dye concentration, and consequently enhanced the color strength for all the dyed samples. Fabric cover factor has significant effect on fabric strength as compared with other dependent variables.

Absorption kinetics and thermodynamics of cationic dyeing on easily dyeable copolyester modified by 2-methyl-1,3-propanediol

In the paper, adsorption kinetics and thermodynamics of C.I. Basic Red 46 (BR46) on the 2-methyl-1,3-propanediol (MPD)-modified cationic dyeable copolyester (MCDP) fabric were investigated at the temperatures of 80, 90 and 100 °C. The adsorption data obtained at different temperatures were applied in pseudo-first-order and pseudo-secondorder kinetic models. The pseudo-second-order model could be used to explain the adsorption kinetics more effectively and predict the rate coefficient (k 2), equilibrium dye sorption capacity (q e ), and the half dyeing time (t 1/2) at different temperatures. In addition, the activation energy of adsorption (E a ) was determined based on the pseudo-second-order rate constant. The equilibrium data of adsorption were found to conform to Langmuir isotherm with the higher correlation. Moreover, the determined thermodynamic parameters including adsorption affinity (−Δμo) and enthalpy change (ΔHo) showed that the dye adsorption onto MCDP was a spontaneous, endothermic, and chemisorption process.

Investigating the effects of different loadings of a nanostructured hyperbranched polymer on the kinetic parameters of disperse dyeing of modified poly(ethylene terephthalate) sheets

The kinetic parameters of disperse dyeing of polyethylene terephthalate (PET) sheets modified by a nanostructured hyperbranched polymer were investigated in terms of dyeing rate constant, time of half-dyeing, diffusion coefficient, and activation energy of the diffusion. The results were compared with those of pristine PET. The surface morphology, surface structure, and thermal properties of modified PET sheets were also studied by atomic force microscopy (AFM), attenuated total reflectance infrared spectroscopy (ATR-FTIR), and differential scanning calorimetry (DSC). Results indicated that the crystallinity and glass transition temperature of modified samples were decreased compared with that of the pristine PET. The diffusion coefficient of dye molecules increased by increasing temperature of dyeing. The highest diffusion coefficient was obtained for the modified PET sample containing 2 wt% hyperbranched polymer while pristine PET sheet showed the lowest one. The activation energy of diffusion of dye into the modified PET sheets was lower than that of the unmodified PET.

Dyeing Kinetics of Collagen Modified PAN Fiber

PAN fiber is one that contains at least 85% by mass of acrylonitrile co-monomer in the polymer chain. It has low moisture-absorbency and electrostatic tendency. The moisture regain of collagen modified PAN fiber is increased. Dyeing kinetics of collagen modified PAN fiber was studied using Cationic Red X-GRL dyes, including dyeing rate curve, equilibrium dyeing uptake, half dyeing time, dyeing rate constant and diffusion coefficient. The results show that: compared with PAN fiber, the equilibrium dye uptake decreased, half dyeing time, dyeing rate constant and diffusion coefficient reduced, and the dyeing behavior of collagen modified PAN fiber become worse than that of PAN fiber.

Kinetics and Thermodynamics Studies of Monascus Red Dyeing on Wool

The mechanism of monascus red pigment dye on wool fiber was studied by analyzing of dyeing kinetics and thermodynamics. The results showed that the dyeing rate is quite high at the beginning of dyeing at 70°C-100°C.The diffusion coefficient rise while half-dyeing time decrease With the temperature rise. Its adsorption accords with the combination of Nernst and Langmuir adsorption model. Its enthalpy and entropy of dyeing was 15.21kJ/mol and 46.87J / (mol·K) respectively, which show that wool dyeing with monascus red is a endothermic process. This theoretical is useful to built dyeing process for wool fiber with monascus red.

Synthesis of Cationic Bolaform Surfactant and its Application Performance of as Levelling Agent

Dodecane-1,12-bis (oxy-2-hydroxy-propyl trimethyl ammonium chloride) (DBA2-12), which belongs to the cationic bolaform surfactants, was synthesized by two-step reactions in this study. The structure of the product was characterized by IR. The IR spectra showed the characteristic bands corresponding to the stretching vibration of C-N, C-O, and-OH groups. The influence of DBA2-12 on the kinetics and thermodynamics of the dyeing of acrylic fibers with cationic yellow X-5GL were investigated. The results showed that the bolaform surfactant had significant retarding effect for cationic dye, the dyeing rate constant and equilibrium dye-uptake was decreased, half-dyeing time was increased by the addition of surfactant DBA2-12. Meanwhile,surfactant DBA2-12 declined the partition coefficient,affinity and dye saturation value. It is concluded that bolaform surfactant DBA2-12 can be used to control dyeing rate of cationic dyes on acrylic fibers.

The Kinetic Research on the Disperse Dyeing Process for PLA Fabric

In this paper, three disperse dyes were selected to study the kinetic dyeing model of PLA fabric. Based on the dyeing results and the SEM spectrum of PLA fabric before/after dyeing, the kinetic dyeing model was established. Besides, the half-dyeing time and the diffusion coefficient of the disperse dyeing process were also tested. These research results will be very helpful to the development of the application of PLA fabric and also set a theoretical base for the dyeing of such environmentally friendly fabric.

Effect of Ozone Treatment on the Dyeing Properties of Mulberry and Tassar Silk Fabrics

Ozone treatment has been carried out on silk fabrics and changes in the properties of the fabrics were reported recently. Further extending the work, in the present study, the dyeing studies of ozone treated mulberry and tassar silk fabrics were carried out using CI Acid Red 88. This type of study has not been carried out before. The results are quantified and expressed in terms of the dye uptake (DU), Equilibrium dye uptake (EDU) and half dyeing time (t1/2). It has been found that the ozone treatment reduced the DU of silk fabrics irrespective of whether they were in a raw or degummed state. The DU was found to be the highest at pH 12. At other pH levels, it was lower and the DU increased as the pH increased from 4 to 7. The lowest DU of ozone treated fabrics was found to be 50% wet pickup (WP) compared to 10% and 100% WP. The higher the treatment time (TT), the lower the DU. the EDU of the treated mulberry and tassar silk materials were lower than the untreated materials.

Adsorption Kinetic and Thermodynamic Studies of Silk Dyed with Sodium Copper Chlorophyllin

In this study, silk was dyed into a bright green shade with a natural dye derivative, sodium copper chlorophyllin (SCC). Kinetics and thermodynamics of SCC adsorption on silk in dye bath with and without sodium chloride at different temperatures were investigated. The pseudo second-order kinetic model fitted experimental data well. Addition of sodium chloride increased SCC adsorption at equilibrium qe, increased the diffusion coefficient D and decreased the half dyeing time t1/2. The Langmuir isotherm agreed well with a high correlation coefficient (R2 > 0.99) for dyeing temperatures of 70, 80, and 90 °C with SCC concentration varying from 0.1 to 2.9 g/L. The thermodynamic parameters of SCC adsorption with and without sodium chloride showed significant difference. The adsorption affinity (−Δμ°) and enthalpy change (ΔH°) of SCC dye on silk indicated that the adsorption is a spontaneous and exothermic process. SCC could be a good candidate as a natural green dye for protein fibers.

Enhancement of Cotton and Cotton / Wool Blend Dyeability by Microwave Heating

The dyeing of cotton and cotton/wool blend fabric by using reactive dyes has been studied with both conventional heating and microwave irradiation. The effects of the dye bath pH, microwave power, dyeing time and dye concentration are studied and the resulting shades obtained by dyeing through microwave and conventional techniques are compared. The results of the dyed samples indicate that microwave irradiation is more effective than conventional heating. Color strength values obtained are found to be higher by microwave irradiation. The results of the fastness properties of the dyed fabric are good to very good. The dyeing kinetics of cotton and cotton/wool blend fabrics are also compared by using the two methods. The values of the dyeing rate constant, half dyeing time (t 1/2), stander affinity and microwave efficiency are calculated and discussed. The physical properties of the samples are studied before and after exposure to microwave irradiation by a scanning electron microscope and an x- ray analysis.

Effect of CO2laser irradiation on the properties of cotton fabric

In this paper, a CO2laser was used for treating cotton fabric. By controlling the laser process parameters, resolution (40, 50 and 60 dpi) and pixel time (100, 110 and 120 µs), the fabric properties changed accordingly. Fabric weight and strength decreased with increase of resolution and pixel time. However, yellowing was observed in laser treated cotton fabric but the extent of this yellowing was nearly the same under different laser process parameters. Scanning electron microscopy images showed that the surface morphology of cotton fiber was modified and it was believed that the low stress mechanical properties of the fabric were also modified. The low stress mechanical properties were evaluated by the Kawabata Evaluation System for Fabric (KES-F). The results were thoroughly evaluated and discussed. Dyeing performance of the laser treated fabric was evaluated in terms of dyeability, rate of exhaustion and color fastness. According to the reflectance curves, laser treatment reduced the amount of direct dye absorbed by the fabric and resulted in a higher reflectance. K/S values showed a decreased color strength when the resolution and pixel time were increased. The exhaustion curves indicated that laser treatment could cause color fading on cotton and a slight increase in the time of half dyeing (t½) compared with untreated sample. In terms of color fastness to washing, laser treated samples performed the same as the untreated sample, irrespective of the resolution and pixel time. Laser treated samples had relatively poor crocking results when compared with the untreated sample.