Adsorption of dyes to cotton and inhibition by surfactants, polymers and surfactant–polymer mixtures

A wide-ranging investigation has been made of the adsorption of direct dyes to cotton and of inhibition by surfactants, polymers and polymer–surfactant mixtures. Generally, the selected polymers are extremely effective at inhibiting adsorption of most of the direct dyes to cotton but are less effective at inhibiting adsorption of small, model azo dyes. Micellar solutions of zwitterionic and cationic surfactants can inhibit adsorption of both small dyes and commercial dyes. It is shown that anionic surfactants at sub-micellar concentrations can inhibit polymer-dye interactions due to displacement of dye and/or relocation into micelle-like polymer–surfactant complexes. New insights have been obtained into the interactions of dyes with cotton and with polymers, surfactants or their mixtures, particularly into observed dye selectivities.     

Photoregulated sorption dyes to polymers. II. Adsorption of acid yellow 38 to hydrophilic polymers and its light-induced desorption

Adsorption of Acid Yellow 38 to, and its light-induced desorption from, various coated polymer layers in water have been studied. Diffusion studies were used to determine the degree of competitive binding between the dye and polymers. It was found that the extent of both adsorption and desorption were different for polymer mixtures as compared to single polymer films. The presence of gelatin crosslinked within the polymer layer increased the amount of dye desorbed upon irradiation.     

The accessibility of cotton to anionic dyes

Adsorption isotherms have been obtained for two direct dyes on unmercerised cotton and viscose yarns at the boil in the presence of sodium chloride. Both dyes, CI Direct Red 81 and CI Direct Green 26, show evidence of monomolecular layer adsorption. Controlled acid hydrolysis of cotton was carried out in order to remove non-crystalline cellulose, and dye sorption values were obtained for the residues. Accessible surface areas have been calculated from the saturation values obtained from the reciprocal plots of the adsorption data. The results are interpreted in terms of a crystalline fibril model of the cotton fibre.     

Adsorption of vapors by amorphous polymers

The equation describing sorption of vapors by solutions of low-molecular-weight substances in the case of formation of solvates with a nonvolatile solvent can coincide in form with the BET equation. In calculating the specific surface area with the sorption value, it is necessary to determine the contributions of absorption (dissolution) processes in bulk and adsorption processes on the phase boundary to the overall sorption. Translated from Khimicheskie Volokna, No. 5, pp. 28–30, September–October, 2008.     

Synthesis of solvatochromic merocyanine dyes and their immobilization to polymers

Solvatochromic merocyanine dyes were immobilized onto polymer surfaces and copolymerized with acrylic resins, yielding novel reversibly solvatochromic polymers, which were used as solvent polarity indicators that exhibited different colors in water and alcohols. To generate solvatochromic polymer for solvent polarity indication, two solvatochromic merocyanine dyes containing moieties, which allow their immobilization onto polymer surfaces, or copolymerization with acrylic and vinyl monomers, were sequentially synthesized in four and six steps. Merocyanine dye (E)‐2‐(2‐(1‐(6‐aminohexyl)pyridinium‐4‐yl)vinyl)‐4,6‐dichlorophenolate (AHPVD) was prepared with a terminal aminohexyl group which allowed covalent bonding to activated carboxylated or sulfonated polymeric materials. The dyes were covalently bonded to the polymer surfaces, such as, nylon, polycarbonate, polyethylene terephthalate, and silicone. Solvatochromic merocyanine dye (E)‐2‐(2‐(1‐(6‐acrylamidohexyl)pyridinium‐4‐yl)vinyl)‐4,6‐dichlorophenolate (AAPVD) was synthesized for radical copolymerization with acrylate and vinyl monomers and oligomers. Side‐chain solvatochromic merocyanine‐containing hydrophilic polymers with differential water and alcohol absorption were obtained upon photoinitiated radical copolymerization with specially formulated acrylated resins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44451.     

The application of reactive dyes to cotton by a wet-on-wet cold pad-batch method

Cotton ha been dyed with reactive dyes by both wet-on-wet (WOW) and wet-on-dry (WOD) cold pad-batch processes, and by conventional exhaust methods. The colour yields, in terms of the Kubelka-Munk values as a function of the amount of fixed dye, showed that the WOW method required less fixed dye to produce a given depth of shade than the other methods. It is proposed that the higher colour yields are a consequence of limited dye penetration into the cotton fibre. Compared with exhaust dyeings, WOW and WOD dyeings were clearly ring dyed but, unfortunately, no definitive difference in the degree of dye penetration into the cotton fibres was found despite their colour yield differences. Although ring dyeings often have inferior fastness properties, the WOW dyeings were of equal or slightly superior fastness to repeated washing and to normal daylight in comparison with the other dyeings     

Adsorption of acid dyes by bamboo derived activated carbon

Bamboo, indigenous to Hong Kong and China, is widely used as scaffolding in construction and building projects. However, over 50,000 tonnes of bamboo scaffolding waste is disposed as landfill waste each year. Nevertheless, these wastes can be used as raw materials for the production of a range of high value added activated carbons. The bamboo cane can be heated (charred) at a high temperature in the presence of selected activation chemicals to produce activated carbons for various applications e.g. adsorbents, catalysts or catalyst supports. In the present study, activated carbons produced by thermal activation of bamboo with phosphoric acid were used for adsorption of acid dyes. Two acid dyes with different molecular sizes were used, namely Acid Yellow 117 (AY117) and Acid Blue 25 (AB25). It was found that dye with smaller molecular size, AB 25, was readily adsorbed onto the carbon while the larger size dye, AY117, showed little adsorption. It is possible to tailor-make the carbon for the adsorption of dye mixtures in industrial applications, especially textile dyeing. Furthermore, experimental results were fitted to equilibrium isotherm models, Langmuir, Freundlich and Redlich-Peterson.     

Synthesis and application to cotton of a polymeric black colorant prepared by grafting of reactive dyes to polyvinylamine

A novel polymeric black dye was synthesised by grafting yellow, orange, red, and blue reactive dyes onto polyvinylamine. Such a polymeric black dye takes the onus away from dyers to worry about the compatibility of individual dyes. The polymeric black dye was characterised by Fourier transform infrared, ultraviolet‐visible, and nuclear magnetic resonance spectroscopy. The absorption of the polymeric black dye in aqueous solution was nearly constant across the wavelength range 400–700 nm. Compared with a black mixture of reactive dyes with low fixation on cotton, which was prepared by mixing yellow, orange, red, and blue reactive dyes, the polymeric black dye reached 99% fixation on cotton through the use of a crosslinking agent. The colorimetric properties of cotton dyed with the polymeric black dye and with the black mixture of reactive dyes showed that better blackness can be obtained by using the polymeric black dye. Analysis of the thermal stability and penetration ability of the polymeric black dye showed that the polymeric dye has high stability in the application and a uniform distributution in the cotton fabric.     

Neutral-fixing reactive dyes for cotton.

Research into a new type of reactive dye based on the monochlorotriazine group is described. Reactive dyes of the 3-carboxypyridino-1,3,5-triazine type have been investigated, with a nicotinic acid leaving group, having high stability and fixation efficiency. Dyes of this type react with cellulose in a neutral bath, so widening the scope of reactive dyeing. A classification scheme for reactive dyes is outlined.     

头发对水中阳离子染料的吸附特性

采用静态吸附法对比了2种阴离子染料和2种阳离子染料在头发上的吸附能力,并测定了头发对阳离子染料碱性品红和亚甲基蓝的吸附动力学和吸附等温线,用准一级、二级动力学模型和Langmuir、Freundlich等温吸附模型进行拟合,计算了热力学参数。结果表明,头发对阳离子染料吸附能力较强,而对阴离子染料吸附能力较差,这主要和头发表面与染料之间电性引力有关。头发对碱性品红和亚甲基蓝在中、碱性条件下吸附效果较好,120 min达到吸附平衡,相同条件下,吸附量:亚甲基蓝>碱性品红。准二级动力学模型和Freundlich等温吸附模型能较好地描述头发对阳离子染料的吸附过程。吸附热力学参数计算结果表明,该吸附是一种自发、吸热、以多分子层吸附为主的物理过程。     

Printing of cationised cotton with reactive dyes

The printing properties of cationised cotton that had been pretreated with 2,3-epoxypropyltrimethylammonium chloride were examined. Fixation (steaming) time, colour yields, colorimetric properties, fastness properties, staining of the white grounds and penetration behaviour were evaluated for a number of reactive dyes with cationised cotton fabrics. The cationisation of cotton was found to be very effective in reducing steaming times and washing off processes, and in increasing colour yield. Fastness and other properties of the printings are also discussed.     

Dyeing of cationised cotton with acid dyes

The production of cationised cotton fabrics, via Sandene 8425, 1, 1-dimethyl-3-hydroxy azetidinium chloride and 1, 1-diethyl-3-hydroxy azetidinium chloride, greatly enhances the exhaustion and fixation of acid dyes. This paper shows that these dyes can be used in the absence of salt in a neutral medium. Wash fastness, light fastness and other properties were studied.     

液相色谱法考察不同聚合物的吸附量

采用液相色谱法对聚合物溶液浓度进行分析检测,以多孔硅胶和无孔油砂为吸附介质,考察不同聚合物的吸附损耗特性。结果表明,色谱法分析速度快,完成一次分析检测不足3 min;定量误差小,重复测试相对标准偏差<5%;由于不同类型聚合物的结构组成存在差异,因此需分别建立对应的定量工作曲线。聚合物在不同吸附介质上的吸附量均较低,吸附介质粒径大小、多孔性及温度对吸附量的影响均较弱;聚合物的分子量增大,吸附量稍有增高,疏水基团增多,吸附量稍有降低;基于聚合物吸附量较低的结果,后期进行相关吸附滞留损耗研究时,可忽略聚合物在地层中的吸附损耗效果。     

Laser protection with optical limiting by combination of polymers with dyes

Lasers are becoming more and more common and can damage eyes and sensors, so arise the need for efficient protection. A possibility is the use of filters with optical limiting abilities. Optical limiting leads to a reduced transmittance of these filters above a certain light energy. Solid-state optical limiting filters consist frequently of poly(methyl methacrylate) (PMMA). Using dyes is an often used way to provide optical limiting qualities to polymers. PMMA does not offer the possibility to attach the dye covalently to the polymer chain. Poly(lactide), also a transparent polymer, has so far not been used for filters for optical limiting. Its polymerization mechanism offers a simple possibility to a covalent binding of the dyes, by using them as initiator. This should be, like the attaching of big side groups to dyes, a possibility to increase stability of dyes against aggregation. Hybrids out of polymers and dyes and filters thereof could be produced. The polymers were analyzed by nuclear magnetic resonance, gel permeation chromatography, and nonlinear optical measurements. Including azophloxine leads to an attenuation of the laser beam in the range of 10⁻³ and Eosin B even to 10⁻⁵. The eosin sample shows a two magnitudes better attenuation then usual guest–host systems like poly(methyl acrylate) with carbon nanotubes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47150.     

Synthesis and dyeing properties of polyvinylamine dyes for cotton

Novel polyvinylamine dyes were designed and synthesised from poly(N‐vinylformamide‐co‐vinylamine) and reactive dyes, then used to dye cotton fibres by the dip‐pad‐steam process, with the dyeing methods being examined in detail. Each polyvinylamine dye was fixed to cotton without a crosslinking agent through covalent bonds formed between the reactive group of the dye and the cotton fibres. A fixation of 99% was achieved, with grades of 4 and 4‐5 wash and dry‐rub fastness, respectively.     

Adsorption of reactive dyes from aqueous solutions by layered double hydroxides

BACKGROUND: Water‐soluble reactive azo dyes are the most problematic dye house effluents, as they tend to pass through conventional treatment systems unaffected. The release of these compounds into the environment is undesirable and their removal becomes environmentally important. In this work, synthesis, characterization and sorption properties of hydotalcite‐like compounds (Mg/Al and Mg/Fe), calcined and uncalcined, were investigated for the removal of the reactive azo dye Remazol Red 3BS. RESULTS: The calcined compounds present higher surface area than the uncalcined. The optimum pH for sorption was found to be 6. Thermodynamic analysis reveals that the sorption is spontaneous and endothermic. Equilibrium data were fitted by a Langmuir model, and kinetic data by a second‐order model. The calcined Mg/Al compound showed the highest sorption capacity, at 0.125 mmol g^?1. Regeneration of dye loaded derivative is achieved using the surfactant SDS. CONCLUSIONS: The prepared hydotalcite‐like compounds and especially calcined Mg‐Al exhibited significant adsorption capacity, kinetics, and regenerative ability. Its potential applicability as sorbent should be tested in a large‐scale implementation. Copyright © 2011 Society of Chemical Industry     

纳米二氧化钛包覆沙对水中有机染料的吸附

以Ti(SO_4)_2和库布齐沙漠沙为原料,制备了纳米二氧化钛包覆沙。以X射线衍射及氮气吸附-脱附分析对样品进行了表征,并测试了合成样品对刚果红的吸附性能。结果表明,制备的样品为二氧化钛与沙子的纳米复合物,其比表面积随二氧化钛含量的升高而增大,最高可达87.1 m²/g。且该纳米复合物对刚果红的吸附性能与溶液酸碱度有关,吸附符合准二级吸附动力学模型以及Langmuir吸附等温式,为单分子层吸附,最大吸附量为246.3 mg/g。     

Anchoring β-cyclodextrin to retain fragrances on cotton by means of heterobifunctional reactive dyes

Cyclodextrins are cyclic oligosaccharides which are able to form complexes with a wide range of organic compounds, including fragrance oils. As a result of the complexation, the vapour pressure of the volatile substance is reduced and its release is better controlled. To achieve this, β-cyclodextrin can be anchored to cellulose by means of a chemical linkage provided by heterobifunctional reactive dyes.     

Continuous dyeing of cationised cotton with reactive dyes

Cotton fabrics pretreated with cationic starch have been dyed with reactive dyes by a continuous dyeing method and the pretreatment conditions influencing dyeability of the treated cotton investigated. Cationised cotton has been found to give level dyeing without the presence of salt and dye fixation is improved compared with untreated cotton. The dyeings show good wash and rub fastness.     

木质素生物炭磺酸对水中阳离子染料的吸附性能与机制

以木质素磺酸钠(LS)为原料,采用浓硫酸一步氧化碳化的方法在60℃和210℃下分别制备了木质素生物炭磺酸SLBC-60和SLBC-210。SLBC-60磺酸基、羧基和酚羟基含量分别为1.66,1.40,4.41 mmol/g,而SLBC-210磺酸基、羧基和酚羟基含量分别为0.34,3.22,5.41 mmol/g。对比评价了它们对亚甲基蓝(MB)的吸附效果,结果显示,在pH=1～10溶液中,SLBC-60对MB保持高吸附量(>463.9 mg/g)和高去除率(>91.9%),而SLBC-210对MB吸附量<231.5 mg/g、去除率<45.8%,结合生物炭结构和Zeta电位分析,这可能与SLBC-60富含磺酸基官能团及其在pH=1～10溶液中表面均富集负电荷有关;优化pH、吸附剂加入量、吸附时间等参数,得到SLBC-60对MB、罗丹明B和孔雀石绿饱和吸附量分别为755.1,926.1,1 008.2 mg/g,且吸附性能不受一价金属离子影响。此外,SLBC-60对MB的吸附等温线符合Langmuir模型(R²=0.998 9),吸附动力学符合准二级动力学方程(R2=0.998 9),吸附动力学符合准二级动力学方程(R²=0.999 5),说明该吸附以单层化学吸附为主。因此,改性制备的木质素生物炭磺酸可作为高效的阳离子染料吸附剂,有望应用于印染废水治理。