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In this study, the removal of a series of acid dyes by hybrid polymer adsorbent was investigated. Textile industry wastewater is mainly consisted of suspended solid particles and organic compounds with complex and nondecomposable structures. Treatment of such wastewaters has received much attention by researchers because of high water consumption and the presence of various chemical compounds, especially dyes. The use of polymers has recently attracted much attention for the treatment of textile wastewaters. According to the literature, hybrid polymers are highly capable of adsorbing dyes. In this research work, polyacrylamide/iron sulfate (PAM-FeSO₄) hybrid polymer was successfully synthesized through solution polymerization of acrylamide with ammonium persulfate and sodium thiosulfate and gradual addition of iron sulfate. The hybrid polymeric adsorbent was then used for removing acidic dyes with different chemical structures.

The effects of various experimental conditions and parameters, such as initial concentrations of dye and adsorbent, on the adsorption capacity of the adsorbent were investigated. The dye concentration was measured by an UV–vis spectrophotometer. The adsorption equilibrium was studied by plotting adsorption isotherms. The experimental data was fitted to Langmuir and Freundlich isotherms.

The adsorption experiments indicated that the PAM-FeSO₄ hybrid polymer has a high adsorption capacity (117.64 mg g⁻¹ for the Orange ІІ and 80.64 mg g⁻¹ for the Sunset Yellow [SY]) when 80 mg of adsorbent was immersed in the dye solution (1 g L⁻¹) with a pH of 11 at 25°C. The analysis of the equilibrium isotherms using the Langmuir and Freundlich isotherms indicated that the Langmuir model fit well to the experimental data.

To the best of the authors’ knowledge, this study is original. The removal of acid dyes such as Sunset Yellow and Methyl Orange using PAM-FeSO₄ hybrid polymer as flocculant was done for the first time.

Eight reactive auxiliaries that act as dye resist agents and differ in number of ionic charges and molecular weights are synthesized and their dye resist effect on wool is evaluated. The results obtained indicate that reactive auxiliary A8 exhibits the highest dye resist effect which means that an increase in the number of ionic groups and molecular weight of an auxiliary leads to better electrostatic repulsion of the dye and thus improves the resist effectiveness. The effect of the dye bath pH, salt concentration, dyeing temperature, dyeing time, and concentration of dye and auxiliaries, are also studied. The fastness properties of the dyed fabric are evaluated. The resist effect achieved with the differential dyeing technique is consistently better than that with dye resist treatments for the eight auxiliaries. When treated wool is dyed in competition with untreated wool, the latter tends to take up the greater part of the dye in the dye bath.

Catechu liquor, which is deep brown-red in color, was purified with a micro-filtration membrane and the stability of catechu dye to different levels of temperatures and pH were investigated in this paper. The effects of the dyeing conditions on color characteristic values and color fastnesses of the dyed wool fabrics were also investigated. The results show that the liquor of catechu dye is stable at pH values of 3-7 and its color changes to a deeper brown-red when its pH value is above 8. The preferable dyeing conditions for wool fabric with refined powder catechu dye are as follows: dyeing temperature of 100±C, pH value of 6.5 for the dye bath and catechu dye of 1-4% (o.w.f).

The dyed wool fabric has good color fastnesses to washing, alkali perspiration and dry rubbing. However, its color fastness rating to wet rubbing is poor, ranging from 2-3. Further research will be needed on this aspect.

Linen fabrics were cationized using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride in alkaline medium. The cationized linen fabrics were dyed independently, with different dyestuffs, namely reactive, direct and acid dyes in absence of salt (no-salt dyed). Factors affecting the nosalt dyeing process of cationized linen fabrics were investigated. These factors included dye concentration, pH of the dyeing bath, dyeing temperature and time as well as the chemical nature of the dyes used. The dyed samples were monitored for color strength (K/S) after soaping and after DMF extraction as well as fastness properties. It was found that for all dyestuffs used, the magnitude of K/S of the dyed samples depends on the nature of the dyes and the conditions used in each case. It was also seen that for no-salt dyeing of cationized linen fabrics, the maximum K/S was achieved at dye shade 2.5 % (ows) and dye bath’s pH 7-9, at 60°C for 20 minutes. In addition to this, the color strength was much higher in case of cationized and no-salt dyed samples compared with the uncationized and traditionally salt-dyed linen fabrics; meanwhile, the overall fastness properties were comparable. Microscopic examination of the cationized and no-salt dyed linen fabrics showed an excellent dye penetration and no evidence for the ring dye phenomena was observed.

Three series of azo dye systems are considered, namely, 5‐oxo‐2‐pyrazoline azo dye systems 9 a‐d,1‐oxo‐pyrazolo pyrazole azo dye systems 10 a, b, c, e, 11 a, b, c, e, 12 a, b, c, e, 13 a‐d and 6‐oxo‐pyranopyrzole azo dye systems 14 a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed. Colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.

Based on clarifying the structural difference between jade fibre and general polyester fibre, this paper aims to study the dyeing properties and dyeing adsorption mechanism of jade fibre with disperse dye and cationic dye.

The chemical structure and microstructure of jade fibre were briefly explained comparing with ordinary polyester fibre. The dyeing rate curve and dyeing adsorption isotherm of disperse dyes and cationic dyes on jade fibre were, respectively, studied. The dyeing uptake, dyeing absorption mechanism, and the main dyeing process parameters were proposed.

Jade fibre can be dyed with cationic dye and disperse dye. The suitable exhaust dyeing process is 110°C and 40 minutes for disperse dye, 100°C and 60 minutes for cationic dye. The dyeing uptake on jade fibre with both disperse dyes or cationic dyes is much higher than that on general polyester fibre and acrylic fibre, and the dyeing adsorption mechanism belongs to the combination of Langmuir and Nernst adsorption for disperse dyes and Langmuir adsorption for cationic dyes. Comparing with ordinary polyester fibre, jade fibre has the advantage of low temperature dyeing and reduced effluent, as is significant to energy-saving and emission reduction.

Jade fibre is a new type of modified polyester fibre with the function of health protection and energy conservation. There are little technical data in the literature at present about the dyeing property of jade fibre.

This paper aims to examine the loss of tenacity and colorfastness properties of bleached and modified (acrylonitrile, AN and methacrylonitrile, MAN) jute fibres dyed with Reactive Orange 14 and Basic Violet 14.

Jute fibres dyed with Reactive Orange 14 and Basic Violet 14 were studied as a function of exposure to sunlight in air, washing with soap solution and spotting with acids and alkalis.

Dye absorption of Basic Violet 14 was higher compared to Reactive Orange 14 at optimum dyeing conditions. Optimum dye uptake of Reactive Orange 14 required relatively severe conditions compared to that of Basic Violet 14. Whereas, Reactive Orange 14 showed overall good colorfastness to sunlight and moderate in washing compared to Basic Violet 14. All the bleached and modified fibres showed good colorfastness to weak acids and alkalis regardless of Reactive Orange 14 and Basic Violet 14 dyes. The loss in tenacity was higher in the case of non-modified fibres, and among the modified fibres, Basic Violet 14 showed the lowest loss in tenacity in the exposure to sunlight.

Many studies have been devoted to improve the substantivity of cellulosic fibre for reactive dyes. A few efforts were made to improve the light fastness. In this work, investigation will be made on a comparative study of loss of tenacity and colorfastness properties of bleached and modified (AN and MAN) jute fibres dyed with both Reactive Orange 14 and Basic Violet 14 on exposure to sunlight, washing and acid and alkali spotting. Optimum dyeing conditions will also be investigated for economic dyeing.

To synthesize some new heterocyclic disperse azo dyes and their utilization in textile printing.

To prepare 1‐cayno‐1‐substituted aryl azo‐2‐methyl benzothiazole by the reaction of 2‐aminothiophenol with malononitrile and the end product coupled with different diazonium salts. The prepared dyestuffs are established using element analysis, IR measurements, ¹H‐NMR and Mass spectra. Printing pastes containing the prepared dyestuffs and a thickener were used for printing polyester and/or nylon 6 using either transfer printing or traditional printing.

New selected arylazo cyanomethyl benzothiazole dyes were obtained from the reaction of diazotized aniline derivatives with 2‐cyanomethyl benzothiazole as a coupling component. The suitability of the prepared dyestuffs for either heat transfer printing or traditional printing on polyester and nylon 6 fabrics has been investigated. The prints obtained from dyes containing non polar groups which have sublimation properties possess high colour strength as well as good overall fastness properties if compared to those obtained using dyes containing polar groups.

The new heterocyclic disperse azo dyes were prepared from 2‐cyanomethylbenzothiazole and were utilized in preparing pastes for textile printing to print polyester and nylon 6 fabrics. In addition, the variation in substituents on the synthesized dyes could also be studied.

The method of synthesis of the new dyestuffs provides a simple and practical solution to prepare some new heterocyclic disperse azo dyes with low molecular weight, suitable for sublimation in heat transfer printing methods.

The methods for synthesis of the new heterocyclic disperse azo dyes are simple. These dyestuffs could be used in textile printing of polyester and nylon 6 on an industrial scale.

This paper's aim is to evaluate the dyeing performance of newly designed azo dye system based on thiazole substituted for improved dyeing when applied to synthetic fibres.

For improved dyeing qualities, various azo dye systems were synthesised based on polyfunctionally substituted thiazole as the coupling component. The heterocyclic moiety was coupled with diazotised aromatic amines to afford the respective azo or hydrazono systems. The structure of the novel systems was elucidated based on elemental analysis and spectral data. Dyeing performance, electronic spectra and optical properties were characterised based on UV and K/S measurements. Fastness properties were evaluated.

The novel systems were designed so that the functionalities located on the heterocyclic ring afforded structure modification that led not only to good dispersion but also to improved adherence on the fibre. The location of the sites led to constructing a resonating system with higher electron mobility and higher absorption maxima.

The azo dyes, used in the present context were synthesised via a step‐wise pathway leading to new dyes. In addition, the variations in substituents and location of sites on the heterocyclic core could also be studied.

The novel azo dye systems based on polyfunctionally substituted thiazole provided a simple practical access to a series of azo dyes with improved dyeing properties. The availability of starting materials, the simplicity and efficiency to production in good yields and high purity lead to valuable achievements for commercial production.

The designed azo dye systems could find numerous applications as disperse dyes in the fields of dyeing, printing and surface coating. Moreover, the systems can find applications as reactive dyes for wool, silk and cellulosic fibres.

The purpose of this paper is to investigate some novel bis‐hetaryl dyes containing both azo and azo methine chromophores on their molecular structures: two series of different molecular structures of these dyes were synthesised. The spectral characteristics and the relationships between colour and constitution of these dyes in solvents with different polarities were systematically investigated and discussed.

A series of novel bichromophoric dyes containing azo and azomethine chromophores were synthesized using two kinds of reaction routes. 2‐amino‐4‐(p‐substituted) phenyl‐thiazole derivatives, which are coupling components, were subjected to diazotisation with aniline derivatives and then to condensation with benzaldehyde derivatives. By exchanging the synthesis route, two series of bichromophoric dyes could be obtained.

The maximum absorption wavelengths of the obtained dyes would be attributed to the higher bathochromic shift in basic organic solvent with high polarity, such as dimethylformamide, as compared with the solvent with low polarity, such as chloroform.

In the present study, a series of novel bichromophoric dyes were synthesized by means of two‐step pathway. In addition, the effects of substituent on the primary aromatic amine and on benzaldehyde moieties will also be discussed.

This novel synthesis method of the thiazole ring would lead to the formation of 2‐amino‐4‐(p‐substituted)phenyl‐thiazole with heteroaromatic coupling component position at C‐5, and consequently would produce the heteroaromatic diazo component at C‐2 for the preparation of the heteroaryl diazo dyes.

In this paper, the bichromophoric dyes obtained by different synthesis routes would indicate that the effect of solvent polarity should be responsible for the bathochromic shifts of the dyes.