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Tight ceramic ultrafiltration membranes have been proven to exhibit good rejection performance for reactive dye wastewater at high temperatures because of their high thermal and chemical resistance. However, the application of ceramic membranes for the treatment of cationic dye wastewater is challenging because of their surface charge. In this study, a ceramic membrane is modified by grafting aminosilane (KH-551) to enhance the positive charge of the membrane surface. The rejection performance of the charged modified ceramic membrane toward the methylene blue solution is significantly improved. The modification substance is bonded to the ceramic membrane surface via covalent bonding, which imparts good thermal stability. The modified ceramic membrane exhibits stable separation performance toward the methylene blue solution. Overall, this study provides valuable guidance for the adjustment of the ceramic membrane surface charge for treating industrial cationic dye wastewater.

Fe containing nano ZSM-5 composites (Fe/H-ZSM-5) were successfully prepared by chemical vapor deposition method. The physical properties of Fe/H-ZSM-5 were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption-desorption isotherm (BET) analysis. Effects of pH and H2O2 concentration were investigated. The best conditions were found to be pH of 3; 0.3 g.L−1 catalyst and reaction time of 60 min at room temperature. The novel Fe/H-ZSM-5 composite exhibited highly photocatalytic performance of RR-195 degradation and the conversion reached to the value of 92.3 % for after 60 min of reaction.

The investigation of film dosimeters made from polyvinyl alcohol (PVA) films dyed with methyl orange (MO) to enable their use in high dose radiation processing applications was studied. The dosimetric change in these films at pre and post irradiation was studied spectrophotometrically. Radiolytic bleaching was observed in PVA aided films exposed with Cs137 γ-source in dose range of 100-200kGy. The effects of pH, dye concentration and film thickness on the radiation response of the film dosimeters were discussed. The stability of MO-PVA films before and after exposure of radiation was also examined at ambient temperature and was found to be higher for long times at pre and post irradiation stages.

The gamma dosimetric response of the Methylene Blue (MB) in Polyvinyl Alcohol (PVA) films was investigated. The spectrophotometric analysis was done to observe the changes in these films at pre and post irradiation. The PVA based films were irradiated using Cs137 γ-source within dose range (100-200) kGy. The effect of concentration of dyes, pH of the dyed solutions and thickness of dyed films were employed as the dosimetric parameters in this study. The stability of MB-PVA films before and after irradiation was examined at ambient temperature. MB-PVA films were found to be light sensitive. Owing to simple preparation and absence of any toxic solvents during preparation, PVA based films were found to be docile for large-scale production and application for routine irradiation processes of medical equipments.

The study provides the physical and chemical properties of the synthesized photocatalysts, and the doping ion influence on the photocatalytic reactions degradation of two textile dyes (direct dye DY86, and reactive dye RBY) under sun irradiation. ZnO nanoparticles doped with alkaline earth metals (Calcium), and transition metals (Silver and Iron) were prepared by a precipitation method. The nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray, UV–Visible spectrophotometry, and Fourier-transform infrared spectroscopy. The results show that the properties of doped ZnO were strongly influenced by the nature of dopant. This study shows that the photocatalytic activity of zinc oxide was improved by the doped treatment, the order for the catalyst photocatalytic activities is: ZnO/Fe > ZnO/Ag > ZnO/Ca > ZnO. ZnO doped with transition metal, revealed the highest photodegradation efficiency compared to alkaline earth metals. The dye’s removal efficiency by nanoparticles of ZnO doped with Fe, Ag, and Ca is about 95%, 85%, and 81%.

Solar active ternary NiO/CuTiO3/ZnO semiconductor heterojunction were developed by alcoholic dispersion technique. As prepared ternary system and parent photocatalysts were analyze crystalline phase, surface morphology, light absorbance property, electron hole accusation parting and significant functional groups by means of specific physicochemical feature measurements. From the results, enhanced visible light photo mineralization, superior efficiency of charge carriers separation and better photocatalytic degradation of reactive orange 30 were confirmed for ternary NiO/CuTiO3/ZnO semiconductor heterojunction. Hydroxyl radical in the radical trapping experiments confirmed the photocatalytic degradation, which plays an important role in removal of hazardous dye from industrial effluents. This work demonstrates that synergetic effect of CuTiO3 and NiO in which it proves to be a good option for recovering the consumption of visible light of ZnO-based materials in the ternary hybrid conduction bands.

Free radical graft polymerization of diallyldimethylammonium chloride (DADMAC) on cotton was employed to substantially improve the dyeability cotton with reactive dyes under salt-free conditions. The effects of plasma-induced graft polymerization of DADMAC on cotton, followed by dyeing with different reactive dyes, was characterized by Fourier transform infrared spectroscopy. A color fastness wash test was conducted to evaluate the effectiveness of cotton cationization on reactive dye fixing. The results show that the salt-free dyeing process with reactive dyes was effective after cationization modification, and the dye uptake rate and dyeing depth are higher than the conventional dyeing techniques.

Blue, red and yellow chitin nanofibers were obtained using reactive dyes. Since the chitin nanofibers and the dye are covalently bonded, they are resistant to hot water and detergents. Since the dyed chitin nanofibers can be mixed at an arbitrary ratio, purple, orange, and green nanofibers corresponding to the mixed colors could be obtained. The dyed chitin nanofibers were evaluated by the reflection spectrum and the color space (L*a*b*). From the viewpoint of reaction yield and color properties, the appropriate ratio of the reactive dye to chitin was 5% at the maximum. The morphology of chitin nanofibers was maintained even after the introduction of the reactive dye. A resin combined with dyed chitin nanofibers was prepared. By combining with nanofibers, it may be possible to give color and improve mechanical strength to resin while maintaining the transparency of the resin to some extent.

Gamma dosimetric behavior of the aqueous solutions of the Sandalfix Golden Yellow CRL (SGY-145) dye was studied. The sample solutions of two chemical natures i.e., Acidic and Alkaline; were irradiated by Co60 γ-sources in the range 0-100kGy. The “Control samples” were remained un-irradiated and also chemically neutral. The dosimetry was done in three phases i.e., Low, Intermediate and High, ranging from 100-1000Gy, 1-10kGy and 10-100kGy respectively. The found values of the “λmax” and the molar extinction coefficient “ε” of the dye were 467 nm and 3.4×103 mol-1cm-1respectively. The absorbance (A) of the aqueous solutions was studied at the absorption band maxima (λmax). The behavior of “Alkaline and Acidic solutions” was checked with the help of curve fitting

Recently, the utilization of wastes, recovery of high value-added products from waste, and their use as raw materials in other industries with the logic of industrial symbiosis has become an important issue. In this study, removal efficiency of Reactive Orange 16 (RO16) dye from aqueous solution was studied using TiO2 catalyst recycled from an industrial waste effluent. The recycling of TiO2 waste from a paints manufacturing industry was carried out by sintering the TiO2-containing waste. The catalyst usability of TiO2-containing powder was then investigated in the removal of RO16 dye by photocatalytic oxidation process. In photocatalytic oxidation studies, TiO2/UV and TiO2/UV/H2O2 processes were investigated, where the effect of annealing temperature, the effect of H2O2 concentration, and the adsorption and photocatalytic effects on RO16 dye removal were studied. The results showed that 100% RO16 removal was obtained for the 10 mg/L initial RO16 concentration using the TiO2 (1 g/L)/UV process. At high initial RO16 concentration (50 mg/L), 100% RO16 removal was achieved by adding 10 mM H2O2.

Reactive dyes are refractory organic pollutants that should be eliminated from colored effluents before the disposing and photocatalytic processes using TiO2 are very studied to treatment of this type of waste. However, the investigation of the performance of this semiconductor as a composite film with chitosan to decolorization of reactive dyes was not yet performed. In this work, composite films of TiO2 and chitosan were successfully synthesized and immobilized on glass and stainless-steel substrates by a simple molding method (drop casting). The materials were tested on decolorization of Reactive Black 5 aqueous solution (RB5) as a model organic reactive dye under UV irradiation at mild conditions. Photocatalytic process was carried out by irradiating RB5 aqueous solution (100 mg L−1) with 125 W mercury vapor lamp, at 25 °C, for 2 h. Under these conditions, films presented high activity, stability and reproducibility. Their surface morphology, thermal behavior, optical properties and structure were investigated by scanning electron microscopy (SEM), TG/DTG, diffuse reflectance spectroscopy in the UV–Vis region (DRS) and absorption spectroscopy of infrared radiation (FTIR). The non-immobilized composite film was preliminarily evaluated and exhibited a good photocatalytic activity, with 98% of RB5 discoloration. Regarding the immobilized ones, the removal efficiencies ranged between 22 and 49%, depending on the used substrate. The results showed that films are well adhered on the glass, as a substrate, but on stainless steel is necessary to apply commercial primer, by a method cost-effective and easy to perform method. The catalytic film immobilized on 304 stainless-steel presented the highest discoloration result, which opens the perspective of applying this system to textile wastewater treatment by photoelectrocatalysis process, since this substrate has high electrical conductivity.

This study analyzed the influence of operational conditions on the Direct Contact Membrane Distillation for synthetic effluents containing reactive and disperse dyes. Results of the permeate flux demonstrated different behavior of the process according to the class of dye. It was found a higher dependence of feed temperature to reactive dye and the analysis of temperature gradient between feed and permeate demonstrated the possibility of operation with higher temperatures in both streams to increase the permeate flux for both dyes. Feed flow rate influenced more the process with reactive dye, while the permeate flow rate determined this behavior for disperse dye. Energy factors showed that the gain output rate and energy efficiency enhanced with the increase of feed temperature, and the energy efficiency increased only with the permeate flow rate (and not with feed flow rate). The water distillation recovery rate was 97.3 % for reactive and 98.7 % for disperse dye; the color rejection of the dyes was over 98 %. These results indicated the adequate functionality of the process for water recovery of textile wastewater, providing an adequate permeate for possible reuse.

In this paper, ultrafiltration (UF) flat sheet membranes were manufactured by introducing two diverse halloysite nanotubes (HNT) size (5 mu m and 63 mu m) and five different (0, 0.63, 1.88, 3.13, 6.30 wt %) ratios by wet phase inversion. Some characterization methods which are contact angle, zeta potential, viscosity, scanning electron microscopy (SEM) and Young's modulus measurements were used for ultrafiltration membranes. Synthetic dye waters which were Setazol Red and Reactive Orange were used for filtration performance tests. These dye solutions were filtered in three different pH conditions and three different temperature conditions for pH and temperature resistance to understand how flux and removal efficiency change. The best water permeability results were obtained as 190.5 LMH and 192 LMH, for halloysite nanotubes (HNT) sizes of 5 mu m and 63 mu m respectively. The best water and dye performance of UF membrane contains 1.88% w/w ratio of HNT, which showed increased water flux and dye flux of membranes according to different HNT concentrations including ultrafiltration membranes. Scientific and Technological Research Council of Turkey (TUBI.TAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113Y350, 113Y370, 113Y371, 113Y372] This work was supported by The Scientific and Technological Research Council of Turkey (TUBI.TAK) under project numbers of 113Y350, 113Y370, 113Y371 and 113Y372. B.K. (PhD student) did the experiments and wrote the article. M.A. (PhD student) did the experiments and revised the article. T.O.A. (Doctor) did the experiments and revised the article. T.T. (Doctor) did SEM characterization analysis. D.Y.I. (Associate Professor) revised the article. S.U. (Associate Professor) revised the article and is project manager. Y.Z.M. (Professor) revised the article. T.U.D. (MSc and R&D Manager) did HNT characterization analysis. I.K. (Professor) revised the article and is project manager.

Cotton textiles tinting of by direct and reactive dyes using consumption method has been done by nanoparticles technicality. Gadolinium doped Zinc oxide nanoparticles ( Gd3+/ZnO) were successfully coated onto the surface of the cotton fabrics. ZnO and 2%wt ( Gd3+/ZnO) nanoparticles are synthesized by precipitation method. The morphology, microstructure and functional groups were characterized for both of them through X-ray diffraction (XRD), scanning electron microscopy (SEM) , energy-dispersive analysis X-ray spectra (EDX), and FTIR spectroscopy. The diameter distribution of ZnO and 2%wt ( Gd3+/ZnO) nanoparticles were confirmed by (TEM ) analysis, the average size of particles was found to be 100 nm, 50 nm respectively .The dye exhaustion percentage (E%) and color strength (K/S) of direct orange 85 and reactive red 195 onto treated cotton fabrics is generally better than that obtained by using untreated samples under the same conditions . The overall fastness properties to rubbing, light, perspiration, washing for the colored samples are ranging from very good to excellent. Nano treatment improves the cotton surface and decreases the environmental impacts and fabric damage.

We investigate amplified energy transfer in conjugated polymer nanoparticles (CPNs or Pdots) by studying both fluorescence quenching of CPN donors and the sensitization of reactive dye acceptors. B...

Fabric ink-jet printing is a crucial technology of clean production in the textile industry. Reactive dyes and organic solvents are the important component of ink-jet printing ink. The structure, h...

Traditional dyeing of cotton fabrics with reactive dyes has produced many environmental problems. Therefore, it is important to investigate the relationship between dye molecular structures and dyeing properties for cleaner procedures. Here, the properties of five azo-based reactive dyes with different substituents and reactive groups were studied. The dyes had similar molecular shapes, sizes, and chromophore structures. Differences were in the aromatic rings, the number of sulfonate groups, and the position of vinyl sulfonate on the benzene ring. The dye substantivity (S%), exhaustion (E%), reactivity (R%), fixation (F%), color strength, salt effects, alkali effects, and color fastness were investigated and analyzed. Different substituents on the dyes had a little effect on the ultraviolet-visible absorption maximum wavelength. In addition, the requirements of salt and alkali to produce the maximum color strength varied for different dye structures. The dye containing a naphthalene ring, three sulfonate groups, and a vinyl sulfonate at the para-position of the benzene ring produced the highest color strength and fixation values. Color fastness was almost the same for each dyed sample, except for the wet-rubbing fastness. The results should be useful for developing new dyes and environmentally friendly dyeing techniques.

In textile inkjet printing, understanding the effect of viscosity and surface tension of a reactive dye ink on droplet formation is of great significance. As an organic ecofriendly solvent, polyethylene glycol with a molecular weight of -400 g/mol (PEG400) was used to prepare reactive dye inks with or without Surfynol 465 (S465) to explain separately how viscosity and surface tension affect the droplet formation of a reactive dye ink. The intermolecular interactions in the ink and physical properties of the ink were investigated by measuring the visible absorption spectra, hydrodynamic radius, viscosity, and surface tension. Droplet formation under a single variable influence of viscosity or surface tension was observed by taking photographs using a high-speed camera. Results show that a high ink viscosity condition generates no satellite droplet formation and a slower droplet velocity, and a higher surface tension tends to cause ligament rupture from the nozzle tip and the droplet. Moreover, a twill cotton fabric printed using the PEG-S465-dye ink at a 30% PEG400 concentration showed higher ink penetration, dye fixation rate, ideal color strength, and rubbing fastness.

The negative effects of dye-contaminated wastewater on humans and the environment are well known, so the wastewater must be treated carefully before discharge into the environment. To overcome those impacts, the search for environmentally friendly and low-cost materials is essential, especially in developing countries The objective of the present study was to determine the feasibility of using bauxite from Malaysia as a new and efficient ceramic, hollow-fiber membrane for the degradation of reactive dyes in wastewater. A porous, hollow-fiber membrane was fabricated from bauxite (BHFM) using a phase-inversion technique, followed by sintering at various temperatures. The BHFM consisted of two types of voids, having either a finger-like or a sponge-like structure. As the sintering temperature was increased, the porosity of the BHFM decreased from 46.5 to 9.5%. The greatest mechanical strength of 308.1 MPa was achieved when the BHFM was loaded with 55 wt.% of bauxite and sintered at 1450°C. The remaining 45 wt.% consisted of solvent, polymer binder, and dispersant. The BHFM functioned well as a membrane for microfiltration and a support membrane for ultrafiltration. BHFM with loading of 45 wt.%, 50 wt.%, and 55 wt.% successfully eliminated 90%, 94%, and 98% of 10 ppm reactive dye (RB5) when sintered at the highest temperature.

In this research, utilizing of Arabica spent coffee ground oil was investigated for textile processing applications including scouring and reactive dyeing for cotton. The spent coffee ground oil was extracted using hexane and its chemical compositions were analyzed. The synthesized biosurfactant from spent coffee ground oil was investigated for use in cotton scouring. The results showed that the biosurfactant could well work as a scouring agent for cotton. Much better water absorption and reduced yellowness on cotton were achieved but higher applied concentration was needed as compared with the commercial wetting agent. It was also found that scouring efficiency of the biosurfactant could be promoted by adding alkali i.e. sodium carbonate, into a scouring bath, resulting in a satisfactory scouring level. A study on utilizing spent coffee ground oil in reactive dyeing process informs that by incorporating the oil into an aqueous dyebath to create oil/water dual-phase dyeing system, the dye exhaustion and color yield of Reactive Red 120 dye obtained on cotton could be enhanced without adding salt. This promotes a development of salt-free reactive dyeing process.

The present study shows sorption capacity of the metallurgical dust, for the anionic dye—Reactive Blue 19, from aqueous solutions and real textile wastewater. The sorption processes were carried ou...

One of the main drawbacks of heterogeneous photocatalysis is the high consumption of electrical energy generated by conventional lamps. This study proposes a methodology to find the best distribution of light emitting diodes (LEDs), i.e., the least amount of elements, and the optimum distance between them in order to substitute conventional lamps in photocatalytic processes, and a performance analysis in terms of energetic efficiency, using for this the Electric energy per order (EEO) Figure-of-merit and the cost results for the degradation of the textile reactive dye Orange PX-2R by means of UV/TiO2 process, using conventional lamps and different geometrical patterns of LED arrays. The obtained experimental results show that it is possible to replace sources of high-energy consumption by UV-LED arrays adapted to the specific needs for a given photocatalytic reactor obtaining suitable oxidation results, and the rate of decolorization obtained is similar to the results obtained with conventional lamps; however the UV-LEDs require 70% less electrical energy (178 vs 628 kWh/m3/order) than UV-lamps. Consequently, the use of UV-LEDs enables to degrade 3.5 times more dye with the current energy consumption of UV lamps. Finally, the proper choice for an array can generate additional energy savings.

In the present work, an ultrasound-assisted reverse-precipitation method was applied as a new approach for the synthesis of CuxO/Fe2O3/MoC. In the sonication method, a bath type sonicator as a simple, cost-effective, and low intensity sonicator was used. To determine the influence of ultrasonic waves on the morphology and application of nano-hybrid as nano-sorbent, it was also synthesized using the reverse precipitation method. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), Zeta-potential measurement, and vibrating sample magnetometer (VSM) techniques. The XRD analysis confirmed that the sono-synthesized sample has higher crystallinity than the conventional one and CuO/Cu2O/MoC/Fe2O3 phase was obtained under ultrasound. According to the TEM and FESEM, sono-synthesized nanoparticles were rod-like with a width and length of 3 nm and 40 nm, respectively. Also, a well-dispersed shape and uniform morphology of nanoparticles were obtained using sonication. In comparison with the conventional nano-hybrid, this structure results in more void and accessible sites for adsorption of pollutants. The efficiency of resulting nanoparticles in adsorption of reactive dyes as a model of the pollutant was evaluated by sorption and sono-sorption processes. The sono-synthesized sample removed the pollutants more efficient than the conventional sample. The removal efficiencies were about 99% for the removal of reactive dyes using the sono-synthesized sample and sono-sorption method. Besides, determining factors including pH, pollutant concentration, temperature, and contact time were optimized in the sono-sorption and sorption processes. A colorimetric method based on RGB value was used to determine dye concentration in aqueous media. The images were taken by a smartphone and analyzed by ImageJ software. The accuracy of RGB results was confirmed by a UV–Vis spectrophotometer.

A simple design and low cost miniaturized reactor integrated with interchangeable thin film TiO2 nanolayer was successfully fabricated for the photocatalytic degradation of azo dyes. The TiO2 nanofilms were prepared by sol-gel dip-coating method, while the miniaturized reactor was fabricated on poly methyl methacrylate (PMMA) substrates, using a laser cutting machine. The performance of the miniaturized reactor for the photocatalytic degradation process was investigated for the degradation of a commercial dye (Novacron Red C-2BL). About 98% degradation of the commercial dye was achieved after 100 min in a stopped flow system, and 15% in a continuous flow system. The effect of different operating variables such as pH, initial flow rate, light intensity, layers of the nanoparticles, and temperature on the photocatalytic degradation was studied and the optimum operating conditions were determined to be: inlet flow rate of 0.05 ml/s, pH of 7, UV power 82 W and using a multi-layer of TiO2 thin film in the miniaturized reactor. The reaction kinetics was described as pseudo first order kinetics and rationalized using the Langmuir–Hinshelwood model.

The design and development of an environmentally benign porous adsorbent for effective simultaneous adsorption of organic dyes and heavy metals from water are important but remain a big challenge. Herein, we have designed a layered double hydroxide/metal-organic framework-based hierarchical nanocomposite (LDH/MOF HNC) by a facile, room-temperature in situ approach. This paper for the first time reports a hierarchical trimodal micro-meso-macroporous LDH/MOF composite with a high surface area (surface area 1282 m2 g-1 and pore volume 0.93 cm3 g-1), synthesised by uniformly growing MOF nanocrystals on the surface of LDH nanosheet ultrathin films. An attempt is made to quantitatively demonstrate the adsorption data via suitable nonlinear kinetic and isotherm equations for single, simultaneous, and consecutive adsorption of the orange II reactive dye and Cr(vi). Experiments were performed at various values of pH (6.0-11.0), adsorbent dosages (1.0-8.0 mg), adsorbate concentrations (5-500 mg L-1), and temperatures (293-323 K). The Langmuir model revealed a satisfactory fit to the equilibrium data of the LDH/MOF HNC (correlation coefficients R2 > 0.98) with a calculated maximum adsorption capacity of 1173 and 733 mg g-1 for orange II and Cr(vi), respectively, in a simultaneous adsorption system. The results of the study demonstrated that LDH/MOF HNCs could potentially be applied as a promising nanoadsorbent for the simultaneous removal and extraction of toxic dyes and metals from water.

In the present study, degradation of Reactive Orange 7 dye was investigated using a new designed titanium electrode, in which a plate of Ti was coated with multi-walled carbon nanotubes (Ti/MWCNT) via electrophoretic deposition technique. A series of characterizations including field scanning electron microscopy, X-ray diffraction, cyclic voltammetry, scanning electrochemical impedance spectroscopy and chronoamperometric analysis were performed to investigate MWCNT impact on the microstructure and electrochemical properties of Ti electrode. Furthermore, the effect of main operating parameters as independent variables (current density, electrolyte concentration, initial pH, and electrolysis time) on color removal efficiency as response variable were investigated and optimized by central composite design under response surface methodology. The maximum color removal efficiency of 89.1% and chemical oxygen demand removal efficiency of 55% were obtained, under the optimum condition. These results indicate that the presence of MWCNT on the Ti substrate noticeably promoted the electrochemical activity and the electrodes’ property for treatment of dye in aqueous solution.

Cotton dyeing is a very complex process with many variables in which different phenomena occur simultaneously. This study aimed to describe the cotton dyeing process by natural dye, using a mathematical model that consists of three mass conservation equations that depict dyeing cotton in cones, taking a representative volume element at the micro, meso, and macroscales. The first equation describes the concentration changes of the dye in the solution, taking into account the diffusive, convective, adsorptive, and reactive effects. The second equation describes the changes in dye concentration in cotton fiber, considering the diffusive, adsorptive, and reactive effects within an intermediate scale. The last equation describes changes in the concentration of dye in the solution on the macroscale, based on the characteristics of the equipment and the difference in concentration before and after passing through the fiber. In addition, a fluid continuity equation was incorporated, taking into account Darcy’s law. In the simulation of the dyeing process with synthetic dye with initial concentrations of 0.408 and 2.06 kg/m3, RMSE of 0.00221 and 0.0289 kg/m3 were obtained, respectively. For the simulation of a dyeing process with natural dyeing, a behavior similar to the experimental data was obtained.

Microcrystalline α-ZnMoO4 catalyst for degradation of Reactive Black 5 by self-made open air atmospheric pressure pulsating corona plasma reactor was synthesized by electrodeposition, followed by thermal treatment. The effect of electrodeposition current density on the catalyst’ characteristics was examined by SEM, EDX, FTIR XRD and TG. The catalyst enhanced plasma decolourization rate by 7.5 times. The role of the catalyst in the consumption of plasma generated H2O2 and in dye degradation was examined in details for the first time to the best of our knowledge; the catalyst enhanced the generation of ⋅OH radical, a principle dye degradation reagent, by enhancing decomposition of plasma–generated H2O2. The catalyst’ excitation mostly proceeded by the strikes of plasma–generated active species accelerated by electric field, which transferred their energy to the catalyst, causing the creation of electron – holes pairs which attacked H2O2. Decolourization followed pseudo – first order kinetics. Decolourization rate increases with the increase of discharge current density and reactor input voltage. The ratio between cylindrical reactor cell’s diameter and the liquid level in it didn’t affect the decolourization rate. Relatively high energy yield of 1.86 gkWh−1 was achieved for 50% decolourization. TOC removal was 85.4% after 180 min of the treatment.

The porosity, roughness, and thickness of woven fabrics limit inkjet printing quality, which is extremely important for obtaining high-quality inkjet printing images on fabrics. This study reveals the application of poly[styrene-butyl acrylate-(P-vinylbenzyl trimethyl ammonium chloride)] nanospheres prepared via a soap-free emulsion polymerization approach as a novel kind of the cationization modifier for the inkjet printing of different woven cotton fabrics by the pad-cure process. It was found that the nanospheres exhibited an average diameter of 65.5 nm, a zeta potential of +57.8 mV, and a glass transition temperature of 94.7 °C. The nanospheres deposited on three cotton fabrics through the dip-rolling process, resulting in the increase of zeta potential, hydrophobicity and thickness of the fabric, and the decrease of porosity and roughness. The high-quality inkjet printing images can be obtained on fabrics with different structures owing to the differences in zeta potential, hydrophobicity, porosity, roughness, and thickness of fabrics. The plain, twill, and honeycomb weave fabrics obtained high-quality inkjet printing images for portraits, oil paintings, and landscape paintings, respectively. The nanospheres could strongly adsorb on the fiber by electrostatic attraction. The reactive dye molecules in the inks could react with the cationized fibers by electrostatic attractive force, resulting in the increase of the color strength, fixation rates, and outline sharpness. The nanosphere cationization of different woven fabrics offers a new potential method for obtaining high-quality patterns without significantly affecting the fabric handle.

For the first time, the ability of dyeing the montmorillonite (Mt) mineral with reactive dye aiming to prepare a new nanopigment was investigated and the optimum conditions were determined. The prepared nanopigment was characterized by Fourier-transform infrared spectra (FTIR), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET), reflectance spectrophotometer (RS) and colorimetry analyses. The results showed that the dye molecules were attached to the hydroxyl groups of Mt plates through a covalent linkage. Also, the BET surface area values slightly increased after the dyeing process due to the separation of Mt plates and the reduction of particle size because of penetration of dye molecules among the plates. Colorimetry analysis revealed that the intercalation of dye molecules was depended on dye concentration and number of reactive sites on the Mt surface. The prepared nanopigment was used for dyeing the polyester fabric in high pressure and temperature conditions. The SEM, colorimetry, electromagnetic reflectance, flammability, and TGA tests were performed to investigate the properties of fabrics. Results indicated that intercalation of Mt nanopigment in the polyester fiber enhances the flame retardant, electromagnetic reflection and breathability of fabrics. Also, the optimum amount of nanopigment in the dyeing process was reported. It can be suggested that the prepared fabric can be a good candidate for utilizing in military and electronic aspects.

A anew technique represented in this study for evaluating the performance of dyeing cotton fabrics using infrared (IR) heating technique compared to the conventional exhaust dyeing method. The effect of this new technique has been studied on the color strength (K/S), color fastness properties, tensile strength and elongation of the dyed cotton fabrics made of two Egyptian varieties Giza 90 and Giza 95 using Procion H-EXL blue reactive dye with concentrations 2%, 4% and 6% . The color strength values of the infrared heating technique in dyeing were better than those of the exhaust dyeing obtained using the same dye concentration 4% and the same recipes. Also the results for dyeing using infrared heating technique had no bad effect on the color fastness or on the dyed cotton fabric mechanical properties.

One of the major problems in the household machine laundry process is dyes bleeding from coloured garments and then the re-depositing on lighter-coloured garments in the same wash load. Thus it creates staining on the light coloured cloth and also colour loss on the dark coloured cloth. Numerous attempts made to solve the issue but none of the remedies are completely successful. Improper loading of high quantity of dye transfer inhibitor (DTI) polymer also had severe negative effect on coloured garment in terms of colour striping, patchy and unsightly appearance. In this research, the amine based aromatic dye transfer inhibitor polymers pyridine N-oxide (PNO), used for the analysis. The performance of the polymer was optimized for better dye transfer inhibition property in the ‘in wash’ liquor against reactive dye. The findings of the research indicate that the performance pyridine N-oxide against reactive dye was excellent over the commercial DTI polymer polyvinylpyrrolidone (PVP). The addition of detergent diminishes the properties of the PVP, but the PNO overcomes that issues and acts well in presence of maximum quantity of the detergent. The research work optimized the amount of DTI polymer required for a single wash load, as 0.25 g. The level of detergent preferably 10 g/l and the pH value of 8. The findings revealed that the PNO polymer performs excellent against all the commercial dyes and also it is noted that the polymer overcomes the shortfalls of commercially available DTI polymers like PVP.

The Reactive Black 5 and Reactive Red dyestuffs have been synthesized in the laboratory. The synthesis was obtained by diazotization of 1-amino-phenyl-4-beta hydroxyethyl sulfone sulfate ester and coupling with 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid (H-acid) (mole ratio 2:1) (Reactive Black 5Na) and (mole ratio 1:1) (Reactive Red Na). The dye was purified-concentrated by ultrafiltration technology and the permeate (waste) was used as dye bath in the exhaustion of cotton and polyamide with the sodium salt of Reactive Black 5 (RB5Na) and the sodium salt of Reactive Red (RRNa). The same dyeing was also made with fresh water as dye bath. Fastness properties were also measured in both cases and the results were compared. Color measurement results of the dyeings were almost the same when the waste as dye bath was used.

The present paper investigates the effects of breed and age on the dye fixation on wool using a reactive dye. It also examines the optimization of the dyeing process realized using the response surface methodology. The dyeing step was carried out on raw wool using the bichromatic blue dye reagent Cibacron P-3R (C.I. Reactive Blue 49). The factors affecting the dyeing process, such as ammonia concentration, temperature, and the duration of the dyeing time, were studied using the response surface methodology. The performance of this dyeing process was evaluated by measuring the color yield (the dye fixation). The results have shown that the age and the breed of sheep have a significant effect (P

The low utilization of dyestuff in textile coloration leads to serious environmental pollution and wasting of resources. Dye/polymer nanospheres have high absorbing, reflecting and scattering light properties due to the large specific surface area, the regular shape, and the uniform size. In the present study, we report the reactive dye/poly(styrene-butyl acrylate-trimethyl ammonium chloride) composite nanosphere as a highly efficient colorant for cationic cotton fabrics. The dye contents of the four colored nanospheres can reach to 217–404 mg/g. The hydration diameters of the composite nanospheres are 83–101 nm for four different reactive dyes. They have the negative zeta potentials, approximately − 25.3 to − 37.6 mV. The reactive dye/copolymer nanospheres exhibit much more powerful coloration ability for cotton fabrics and higher dye utilization than the ordinary reactive dyes. The color depths of cotton fabrics dyed with colored nanospheres are 2.8, 4.9, 10.6 and 4.2 times of the values of the corresponding dye colored samples. The dye/copolymer nanospheres have much larger color gamut than the ordinary dyes. The color durability and levelness of the dye/copolymer nanospheres on cotton fibers are good enough for practical applications. What’s more important is that the residual dye/copolymer nanospheres in the dye bath can be reused in the next dyeing process. This novel nanosphere dyeing method does not only save the colorants but also avoid the discharging of colored sewage. The reactive dye/poly(St-BA-VBT) nanospheres were successfully fabricated by adding the cationic poly(St-BA-VBT) nanospheres dispersions into reactive dye solutions. This article offered a novel dyeing method for cotton fabrics using dye/poly(St-BA-VBT) nanospheres. These colored nanospheres can endow the cotton fabrics with good color performance and avoid the discharging of colored waste water, which provide a green way for textile coloration.

In this work, a series of magnetic activated carbon/nanodiopside (Fe3O4/AC/Diop) nanocomposites were synthesised and used for the removal of reactive green KE-4BD dye from the aqueous solution. Aft...

In this work, a new method for facile synthesis of covalently colored polyurethane latex was developed. A series of blue dye monomers were synthesized via one-step reaction of a reactive dye and amino compounds, and then employed as chain extenders to react with polyurethane prepolymer in the emulsification process to prepare the covalently colored polyurethane latexes. The chemical structures and the properties of dye monomers and the corresponding polymers were investigated, and the UV–Vis spectra of covalently colored polyurethane featured fairly consistent with dye monomers with maximum absorption wavelength at 620 nm and 580 nm, since the chemical structure of chromophore maintained unchanged. The conversion of dye monomer reached more than 92% with 1.0 wt% dye content, whereas the conversion decreased with the increase of the dye amount and the adding time. Compared with the noncovalently latex film, the light fastness of the covalently colored latex film was greatly promoted due to the chemical bonding of chromophores with polymer matrix.

Color stripping is one of the most convenient approaches for amending various shade faults during dyeing and printing processes. However, conventional stripping processes usually bring a serious risk of environment pollution. The purpose of this work is to develop a novel, sustainable and energy-conserving method for stripping of reactive-dyed cotton substrate by employing a UV/Na2S2O4 system, in which low dosage of sodium hydrosulfite (Na2S2O4) was involved and induced by UV photocatalysis at atmospheric temperature. The effects of stripping parameters such as initial pH value of working solution, temperature and stripping duration on color stripping efficiency and fabric tensile strength were investigated. The results show that the fixed reactive dyes on cotton could be efficiently stripped in the UV/Na2S2O4 system with a photocatalytic initiation and a dipped stripping manner, along with relatively high tensile strength retention by the substrate. Moreover, an optimized photocatalytic color stripping process was recommended for degradation or stripping of the fixed reactive dye molecules in cotton fibers. Furthermore, a successful application of the proposed system was also achieved for stripping a series of the Evercion/Everlight and Megafix reactive dyes fixed on cotton. In addition, the color stripping was further successfully investigated and validated via the variations in structures and surface morphologies of the cotton fibers by utilizing Fourier transform infrared spectrometry, wide-angle X-ray diffraction and scanning electron microscopy analysis.

Reverse micelles using nonionic poly(ethyleneglycol) (PEG)-based surfactant as building block were introduced to encapsulate reactive dye for cotton dyeing. The morphological transition of reactive dyes from well-dispersive spherical form into highly agglomerated form via various surfactant-to-co-surfactant molar ratios and surfactant-to-water molar ratios have been preliminary investigated. The dyeing properties of cotton has been analyzed in terms of dispersion of reverse micelle structure from transmission electron microscopy, identification of chemical signatures of dye-cotton interaction from Raman spectroscopy, color strength and relative levelness. The reverse micellar structures under both highly dispersed and agglomerated forms are in good agreement with color strength and levelness data. The optimization of surfactant conditions can be considered as major parameters for investigating the quality of cotton dyeing including color strength and levelling conditions.

Cotton fabrics have been used in a variety of applications due to its attractive properties of softness, comfort, warmth, biodegradability and breathability. Coating cotton fabrics with photocatalytic materials can extend their use as self-cleaning and other practical applications. In this study, coating of cotton fabrics with dye sensitized/TiO2 for self-cleaning and UV blocking properties has been reported. Phthalocyanine based reactive dye, Reactive Blue-25 (RB-25), has been used as a visible light scavenger for TiO2. RB-25/TiO2 hybrid sol was prepared by sol–gel method and coated on the cotton fabrics via dip-pad-dry-cure method. The coated cotton fabric was characterized by FTIR-ATR, UV–Visible absorption, XRD, SEM and reflectance measurements. The surface studies confirmed the stable attachment of RB-25/TiO2 on the cotton fabric while photocatalytic and UV absorption studies shown that the RB-25/TiO2 coated cotton fabric exhibit substantial visible light driven self-cleaning and UV blocking properties. Rhodamine B (RhB) dye was used as to examine the photocatalytic efficiency of the coated cotton fabric. 91% RhB was degraded in 180 min when exposed to visible light in the presence of RB-25/TiO2 coated cotton fabric.

This work presents the highest color removal efficiency for Textile wastewater by Electrocoagulation (EC) process using Aluminum as a sacrificial anode which is presently used for the purification of many types of water and wastewater. The effecting parameters such as applied electrical current, electrolysis time and initial pH were studied to achieve higher removals. In this process, sample was taken from real effluent of reactive dyes fabric. The performance of Electrocoagulation process was carried out in batch reactor at regular interval of 20 minutes. Obtained results indicated the most effective color removal efficiency was achieved at 0.75A of applied electrical Current. They were (97.5% - 98.1%), at electrolysis time of 120 minutes, pH10, pH7 respectively and COD removal efficiency was (54 % - 65%) at 0.75A, 0.9A respectively. In this work, the initial pH did not strongly affect the removal efficiencies significantly over a wide range. Therefore, adjustment of initial pH before treatment was not required in this practical application. The power consumption was found to be 6 kWh/m3. To determine COD removal rate dependency to electrical current, a kinetic study was carried out and data were in good covenant with the first order kinetic model.

Background and objective: Wastewaters including dyes produced by various industries have serious destructive effects on the environment. Therefore, proposing analytical and numerical mathematics methods simulating dye removal process from industrial wastewaters are great of importance. Methods: In this research, the Fe3O4-activated carbon magnetic nanocomposite was synthesized and its crystalline structure, surface, and magnetic properties were characterized by XRD, SEM, and VSM techniques. Efficiency of the composite adsorbent for decolorization of Reactive Red dye in different conditions was investigated. Then, an artificial neural network was constructed by using Matlab program to predict the removal efficiency of dye onto magnetic activated carbon and the number of neurons in a hidden layer was optimized. pH, contact time, initial dye concentration, and temperature as input parameters and dye removal percentage as an output parameter were considered. Performance of network after its training was evaluated based on the correlation factor. The experimental data were analyzed by pseudo- first- order, pseudo- second- order , and intra-particle diffusion kinetics models.The Langmuir and Freundlich models were used to describe the sorption equilibrium isotherms. Results: . The high correlation factor for testing data showed that artificial neural network model can estimate the experimental data. The intra-particle diffusion kinetics and Freundlich isotherm models best describe the experimental data for the uptake of dye. A relatively low activation energy (34.6 kJ mol-1) suggests that the adsorption involve physio sorption. Maximum adsorption capacity decreased with increasing temperature. Conclusion: Use of network prediction resulted to eliminate experiments and to improve dye removal percentage.

ZnO, TiO2, and CuO nanoparticles were immobilized onto the cotton and wool fabrics at room temperature. The antimicrobial activity of dyed cotton and wool fabrics with reactive dye against S-aureus, E-coli, and C-candida were measured by the optical density method. It was observed that the killing of bacteria and the bacterial cell damage were harmed efficiently. The effect of pre-treatment of cotton and wool fabrics with different NPs metal oxides on the color strength of dyed fabrics was studied. Color strength (K/S) and colorimetric data (L*, a*, and b*) were measured at specific λmax. Besides, washing, rubbing, perspiration, and lightfastness of dyed cotton and wool fabrics were determined. UV blocking and self-cleaning of the treated fabrics were measured accordingly. The obtained results of the pre-treated fabrics with ZnO, TiO2, and CuO nanoparticles would support the current research outputs as a potential production of protective textile.

In this work, we investigated the use of cotton scraps in natura and modified with iron nitrate,in the adsorption of one of the main water contaminants of the textile industries, the reactive black dye. Special attention was paid to the appropriate destination of the spent adsorbent, in compliance with the precepts of the circular economy. Cotton and polyester are excellent candidates for adsorbents and are produced on a large scale worldwide, but fabric wastes do not yet have a wellestablished method of application. We found that fabrics containing different types of fibers or colors maintain the ability to remove dye. The retention promoted by the cotton fabric in natura reached 18.8 mg g-1. After treatment with iron ions, there was an increase in the dye adsorption capacity to 31.0 mg g-1. In addition, the spent iron-containing adsorbent was pyrolyzed at 973 K, resulting in an activated magnetic carbon with a specific surface area ranging from 300 to 565 m2 g-1. Thus, it was possible to convert the used adsorbent into a new material with wide application possibilities.

Digital inkjet printing technology plays an increasingly important role in textile printing. The printing printability of reactive dye inks is the key to improving the quality of printed fabrics. In this study, an eco-friendly and simple method to improve the inkjet printability of reactive dye solutions was proposed. The influence of diethylene glycol on the surface tension, rheology, and dye molecule aggregation properties for three reactive dye solutions was investigated. The jetting performance of dye solutions was explored by observing droplet formation. Moreover, the color performance of printed cotton fabrics, including reactive dye solution penetration, colorimetric values, and color strength, was evaluated. Addition of diethylene glycol could change the aggregation of dye molecules by hydrophobic forces and hydrogen bonds. Diethylene glycol could inhibit formation of satellite droplets by changing the viscosity and surface tension of solutions, which made the pattern printed on cotton fabrics show regular edge sharpness. Furthermore, the dye solutions containing 10% DEG not only satisfied various properties of reactive dye inks but also had the highest color strength and the deepest and brightest colors.