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A detailed study was carried out to compare the removal of Reactive Blue 221 and Red X-5GN dyes using raw Helianthus Annuus L. seed shell as a natural adsorbent. There is no study in the literature for comparing the treatment of these anionic and cationic dyes using the current seed shell in raw form. Bringing a natural waste to the economy that can compete with adsorbents such as activated carbon commercially used in dye removal, will offer important advantages. The variation of initial pH value, shell dosage, contact time and, initial dye concentration was investigated. Reactive Blue 221 was successfully removed at pH 2 with a treatment efficiency of above 90%, while Red X-5GN was treated at pH 4 with a removal efficiency of 97%. Appropriate adsorbent dosages were 4 and 10 g/L for Reactive Blue 221 and Red X-5GN, respectively. Adsorption data of two dyes fitted very well to the pseudo-second-order reaction model with R-2 values of 0.979-0.999. The data were best repreŞented by the Langmuir model for Reactive Blue 221 with an R-2 of 0.986. Freundlich isotherm was the most suited model for adsorption of Red X-5GN dye with an R-2 of 0.996. The maximum uptake capacities were found to be 27.40 mg/g for Red X-5GN and 30.58 mg/g for Reactive Blue 221. The results showed that the conditions of adsorption for each dye can be significantly different. Besides, the potential of this seed shell as an eco-friendly and low-cost adsorbent was exhibited with perfect treatment results. [GRAPHICS]

PurposeThe conventional textile dyeing process requires various operational characteristics, and determining the most reliable factor in dyeing performance has always been a challenge for the textile industry. Thus, the present paper aimed to evaluate the process sensitivity of C. I. Reactive Blue 194 dyeing of cotton fabric using a statistical technique.Design/methodology/approach An L27 orthogonal array-based Taguchi's methodology was used with six parameters and three levels of each parameter. The signal-to-noise (S/N) ratio and analysis of variance were studied using total fixation efficiency (T%) as the response of the process sensitivity.Findings Results showed that dyebath pH was the most influential factor on the process and total fixation efficiency (p-value = 0.00 and contribution percentage 45.03%), followed by dye-fixing temperature, dye mass, electrolyte concentration, dye-fixing time and material to liquor ratio.Originality/value Overall this study provides a foundation for the determination of dyeing process sensitivity that will be useful in textile industries toward further development.

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.

In this work, the treatment efficiency of advanced oxidation processes H2O2/UV enhanced by the addition of a manganese catalyst complex (MnTACN) was investigated on a model dye solution and a real dye-house effluent. The experimental results were evaluated in terms of absorbance (A) and total organic carbon (TOC) reduction. The major degradation products of the model dye solution were identified by high resolution gas chromatography/mass spectrometry analyses. In addition, the toxicity of the final reaction solution after H2O2/UV/MnTACN treatment to Vibrio fischeri bacteria was determined. The results showed that the addition of the H2O2/UV/MnTACN system at in different concentrations of the catalyst solution increased enhance the decolourization rate compared to H2O2/UV for both the model dye solution and real dye-house effluent.

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.

Nano Fe-BTC materials were successfully synthesized by mechanical chemical grinding method. Samples were characterized by X-ray difraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption–desorption, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS). SEM image of Fe-BTC-60 showed the particle size of 40–60 nm. Fe-BTC nanocomposites were tested for the photocatalytic degradation of reactive yellow 145 (RY-145) in aqueous solution. Fe-BTC composites exhibited high photocatalytic activity. Thus, at pH of 3 and high initial concentration of 100 mg RY-145/L, removal efficiency reached the value of 97.45% after 90 min of reaction.

The removal of textile reactive dye from an aqueous solution on a new adsorbent prepared from waste cotton knitted fabric was investigated in this study. Waste cotton textile, used for the production of adsorbents, is a by-product of the cutting of stacked parts of cotton knitwear planned for the production of women’s T-shirts. The degree of efficiency of a paper pattern determines the amount of collected waste. The qualitative and quantitative characterization of the new adsorbent showed carbon and oxygen to be dominant in the chemical composition. A longer contact time means a greater amount of dye on the adsorbent, i.e. the dye concentration in the solution decreases with the duration of the adsorption process. The percentage of removed dye decreases with an increase in the initial dye concentration in the solution. However, the actual amount of adsorbed dye increases as the initial dye concentration increases. The results for equilibrium adsorption show that the Langmuir isotherm can be used for the interpretation of reactive dye adsorption on a new adsorbent. The pseudo-first order model can be fully used to describe the kinetics of dye adsorption on an adsorbent, with respect to valid results for statistical indicators. Based on the results, it can be concluded that the new adsorbent obtained from waste textiles has the potential to remove textile reactive dye from aqueous solutions.

Removal of color from dye-bearing water has been a bothering task from the health point of view and in the aesthetic sense as well. Finding out the effectiveness of Remazole Red RGB dye removal is the aim of the present work using banana stem, an agricultural waste, as an activated carbon. The preparation of the banana stem activated carbon was done in the laboratory by carbonization followed by activation. To assess the impact of varied exploratory variables such as pH of adsorbate, contact time, initial dye concentration and dosage of adsorbent on the removal of Remazole Red RGB dye from aqueous solution adopting batch studies were performed. The Freundlich and Langmuir isotherm models were used to predict the adsorption capacity of adsorbent at equilibrium conditions, the kinetic parameters were also determined. The concentration of dye remaining in the system was measured using a UV visible spectrometer. The batch test resulted in the removal of the maximum of 87% of dye when the dye concentration was 2 mg/L, at an adsorbent dose of 0.5 gm/L and dye pH 4 in 35 minutes. It is established from the studies that the equilibrium data suited excellently both Freundlich and Langmuir isotherms. The maximum adsorption capacity of 14.28 mg/L was established from the Langmuir isotherm model. To state the sorption kinetics, pseudo-first-order and pseudo-second-order kinetic models were evaluated. The intraparticle diffusion model was checked for the adsorption data and it was observed that intraparticle diffusion is not the only rate-limiting step. The regression analysis results indicated that the linear regression model gave the best results. The above detection exhibits that banana stems can be used productively for the removal of color from dye-containing wastewater.

Graphic abstract Cationization of cotton fabrics was performed by exhaustion procedure utilizing four different reagents provided with quaternary ammonium groups: poly diallyldimethylammonium chloride (PDDACl), poly acrylamide-co-diallyldimethylammonium chloride (PAcD), poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized (P42) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Pretreated samples were dyed using Reactive Red 195 dye. The cationic fabrics were analyzed by colorimetric and fastness properties, zeta potential, SEM, FTIR and an estimate of the bactericidal effect. Cationic cotton treated with PDDACl and CHPTAC showed a higher affinity for the reactive dye, with color strength (K/S) values varying from 41 to 48, against 32 for conventional dyeing. P42 presented competitive results with K/S of 27–28. The cationic dyeing considerably reduced the amount of effluent, especially for the CHPTAC samples, which requires a single washing bath for complete removal of unfixed dye. The PDDACl and P42 samples presented bactericidal activity. Supplementary Information The online version contains supplementary material available at 10.1007/s10570-021-04260-4.

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.

A new modified walnut shell (TWNS) was synthesized through sequentially reacting the walnut shell (WNS) with thionyl chloride and triethylamine, and it was applied to adsorb Reactive Brilliant Blue...

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%.

In the present study, calcium peroxide (CaO2) was used separately for potential application as an environmentally friendly and low-cost oxidant for the removal of a textile dye ‘Reactive Black 5’ (RB5) from simulated textile wastewater containing auxiliary chemicals of textile production. The specific morphology, elemental analysis, particle size distribution, specific surface area, identification of crystalline phases and surface functional groups of the synthesized CaO2 were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), laser diffraction (LD), Brunaure–Emmett–Teller method (BET), X-ray diffraction (XRD) and Fourier transmission infrared (FTIR), respectively. X-ray Diffraction analysis confirmed the synthesized oxidant as CaO2 with the tetragonal crystalline structure. The signal corresponded to a bending vibration of O–Ca–O was detected in the fingerprint region of the FTIR spectroscopy. The effects of various independent parameters such as contact time, pH, initial RB5 concentration and CaO2 dosage on decolorization were investigated. The results of the study showed that pH, initial dye concentration and the CaO2 amounts have significant effects on removal of the RB5. The optimum pH was determined 7 for the removal of RB5 by CaO2. 2.0 g CaO2 was found to be sufficient for the removal of 300 mg/L RB5 with 96.93% removal efficiency. Also 82.8% chemical oxygen demand (COD) removal efficiency from simulated textile wastewater (STW) was obtained by 2.0 g CaO2. The results of the present study showed that the CaO2 can be used as an environmentally friendly and low-cost oxidant for effective removal of reactive textile dyes.

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.

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

The color of dye aqueous solution which cannot be removed by coagulation was selected to decolourize it through adsorption process by using novel adsorbents namely Flocs of Ferric Sulphate, Aluminium sulphate and Manganese sulphate. In order to know efficacy of adsorbents, batch sorption studies and equilibrium studies were conducted. Good color removal was achieved with Ferric sulphate at pH::4 and Manganese Sulphate at pH::10, which will be applicable to reduce the industrial dye effluent pollution. Equilibrium data applied to Langmuir Isotherm, was best fitted, stating monolayer formation and kinetic data applied to pseudo second order equation, was well fitted, stating that chemisorption is the rate limiting step.

Colored wastewater is the most important problem of textile manufacturing factories, because it contains pollutants with complex structure and toxic, carcinogenic, and mutagenic properties which are non-biodegradable and sustainable in the environment. Reactive Red 198 (RR198) is one of the types of azo dyes which are widely used in the textile industries. Therefore, in this study, the rate of degradation and mineralization of RR198 by UV/US/H2O2/O3 hybrid process was investigated. Influencing factors including: initial dye concentration (100, 200, 300, 400, 500 mg/L), contact time (12.5, 30, 47.5, 65, 82.5 min), pH (3, 5, 7, 9, 11), UV (125-W), H2O2 (10, 20, 30, 40, 50 mg/L), US (160 KHz) and O3 (33 mg/(L·min)) on the removal and mineralization efficiency of RR198 were investigated. Optimization and modeling of the process was done by CCD method. Based on the results of ANOVA analysis, most effective parameters on the RR198 removal efficiency were ozone, US, UV, time, initial dye concentration, pH, and H2O2, respectively, with an impact percentage of 96.86 and less than 1% for ozone and the rest parameters, respectively. Highest removal efficiency of RR198 was obtained by UV/US/H2O2/O3 hybrid process. Optimal conditions for dye removal including: initial dye concentration of 200 mg/L, reaction time of 34 min, H2O2 concentration of 27 mg/L and pH of seven were determined in the presence of ozone gas, UV, and US waves. In these conditions, the removal efficiency of RR198 and TOC were estimated to be 100 and 40.5, respectively. UV/US/H2O2/O3 hybrid process as an advanced oxidation process (AOP) with advantages such as high performance and speed, no sludge production and toxic residues in the treated effluent containing hard biodegradable compounds such as RR198 from aqueous solutions, so can be recommended and used.

The existing knowledge on the reactivity of green iron particles on textile dye and wastewater decolorization is very limited. In this study, the potential of green iron particles synthesized using grape leaves extract on reactive dye (reactive red 195, reactive yellow 145, reactive blue 4 and reactive black 5) decolorization were investigated. 95–98% of decolorization was achieved for all reactive dyes at 1.4–2.0 g/L of green iron. Maximum decolorization was attained at lower dye concentration and showed very little impact on decolorization when pH was increased from 3 to 11. The pseudo-first-order fit confirms the reaction between iron particles and dye molecules with rate constant 0.317–0.422 and it is followed by adsorption, data fit with pseudo-second-order model. Hence, not only adsorption but also the reduction process is involved in the reactive dye decolorization. Benzene, phenyl sodium, 2-chloro-1,3,5-triazine, naphthalene, sodium benzene sulfonate, benzene 1,2 di amine, anthracene-9,10 dione, aniline, phenol, benzene sulfonic acid were the major intermediates detected in dye decolorization and the respective reaction pathway is proposed. Green iron from grape leaves extract demonstrated better performance and it is recognized as the promising cost-effective material for textile wastewater treatment. HIGHLIGHTS Green iron particles synthesized from grape leaves extract.; Reactivity of bare and green iron particles on textile dye decolorization.; Dye decolorization pathway proposed.; Efficiency of green iron particles on textile wastewater decolorization.; Economic feasibility of synthesized green iron particles on textile wastewater treatment.

Interest in insects as waste biomass bioconverters and their use as valuable resources for fat, proteins, and chitin has increased considerably in the last few years. In this study, proteins were extracted from defatted black soldier fly (BSF) (Hermetia illucens) exuviae by green hydrolysis using superheated water at 150 °C for 20 h, and the remaining chitin was deacetylated into chitosan and used as a finishing agent for polyester fabrics. A total amount of 7% fat, 40% proteins, and 20% chitin was obtained from BSF exuviae. Different hydrolysis times ranging from 1 to 20 h were tried until the complete purification of chitin. The purity of chitin and the obtained chitosan after deacetylation was assessed by Fourier transform infrared spectroscopy and thermal analysis. A preliminary study was successfully carried out to use the obtained chitosan as a finishing agent for polyester pretreated fabrics using citric acid as a grafting agent. The presence of chitosan on the fabric was verified by scanning electron microscopy and by dyeing of the pretreated polyester fabric using a reactive dye with sulfonated groups that are able to be absorbed by electrostatic attraction because of the created cationic nature of the fiber surface treated by chitosan.

Electrochemical oxidation is a promising alternative for the degradation of reactive dyestuffs in residual dyeing liquid, which contains organic dyes, as well as salts such as sodium chloride and sodium sulfate. In this work, three kinds of salts, Na2SO4, NaCl and FeSO4, were selected to study the influence of electrolytes on the electrochemical oxidation of recalcitrant reactive red X-3B, using graphite cathode and dimensionally stable anode or graphite anode. The removals of color and chemical oxygen demand have been evaluated. Color removals were 99.97% and 99.84% with graphite anode and dimensionally stable anode in Na2SO4 and NaCl electrolyte. The corresponding chemical oxygen demand removals were 93.60% and 100%. In contrast, the maximum color and chemical oxygen demand removals were 97.32% and 68.76% in FeSO4 electrolyte. It was found that a combination of NaCl and FeSO4 achieved complete oxygen demand removal for both graphite anode and dimensionally stable anode. During the electrochemical oxidation process, anode and electrolyte exhibited a great effect on pH variations. Based on the cyclic voltammetry and active oxidative species investigations, the oxidation of reactive red X-3B was attributed to indirect oxidation of active chlorine and reactive oxygen species.

Urea-free reactive printing has gained popularity as part of cleaner production in the textile printing industry. Printing additives containing little to no nitrogen are being explored as substitutes for urea. In this study, the hygroscopicity, ability to swell fibers, and ability to solubilize reactive dyes of various additives were compared to explore the intrinsic connections between the structures and the above-mentioned properties. The hydrogen-bond interactions between the reactive dye and additives were characterized by 1H NMR and DSC. Additives with good hygroscopic, swelling, and solubilizing properties were selected for their potential application in urea-free reactive deep printing on viscose fabric. Results showed that among various kinds of additives, glycerol had the best hygroscopicity, 1,4-butanediol had the best ability to swell viscose fibers, and the amides had the best ability to solubilize reactive turquoise K-GL. Hygroscopicity was considered as the most important factor, followed by the ability to swell fibers. When the mixed ratio of glycerol and 1,4-butanediol was 5:5, the color performances of the binary nitrogen-free compound were higher than those of a commercial alternative. Its printing performances came close to those of urea, exhibiting great potential as a substitute for urea. Nitrogen-free alternatives will remarkably reduce the ammonia–nitrogen pollutants emitted into the environment by the reactive printing process.

From sustainable chemistry and engineering perspectives, water and energy consumption are arguably the main issues in the textile industry. Thus, a silicone reverse emulsion dyeing system is developed to dye cellulosic textile with reactive dye. When the amount of dye is the same, the color depth of dyed cotton fiber is 13.82 and the fixation of dye is 87.76% in the silicone reverse emulsion dyeing system. In traditional water-based dyeing system, the color depth of dyed cotton fiber and the fixation of dye is only 9.31, 56.63% respectively. The silicone reverse emulsion dyeing technology does not consumes salts, but it can improve the dye fixation by 31.13%, and decreases the dye discharge by 72.41%. For the hydrolysis of bifunctional reactive dye, the main hydrolysis reaction is the individual hydrolysis of monochlorotriazine or vinyl sulfone at the prophase of hydrolysis. After 30 min, the additional β-hydroxyethyl sulfone and hydroxyl triazine dye are hydrolyzed to dihydroxyl dye. To confirm the hydrolytic reaction energy of dye in different dyeing system, the optimization of molecular structure, the hydrolysis reaction gap and the distribution of electron density on the dye were investigated using density functional theory. The hydrolytic reaction energy gap of bifunctional reactive dye is higher in silicone reverse emulsion dyeing system than that in traditional aqueous dyeing system, resulting the hydrolysis of dye is difficult in silicone oil emulsion dyeing system. The electron density is distributed almost entirely on the carbon–carbon double bond and triazine group in the HOMO of the dye, resulting in the LUMO of dyes can attacked by HOMO of hydroxyl anion. These successful investigations of the dyeing performance and the hydrolysis mechanism of dye explain that reactive dye can keep a long reactivity to fiber and effectively reduce the number of washing times, which greatly reduces the discharge of dyeing waste water.

Reuse of modified fly ash for treatment of dye wastewaters is a promising new technology with the potential to mitigate two waste streams currently having negative effects on the environment. In the present study, cationic fly ash adsorbent was prepared by immobilizing with poly-epichlorohydrin-dimethylamine for treating reactive dye wastewaters. Characterization analyses confirmed that poly-epichlorohydrin-dimethylamine had been immobilized onto fly ash, and this immobilization could change the Zeta potential of fly ash from negative to positive throughout the range of pH from 3 to 11, but could not alter its crystal structure. Static adsorption analyses demonstrated that dye adsorption process was spontaneous and endothermic, and the experimental data were better in accord with pseudo-second-order kinetic model. Column experiments showed that cationic fly ash displayed a dramatically high dye adsorption capacity, which was over 1.5 times more than that of commercial activated carbon. Reusability study confirmed that synthesized cationic fly ash can be used repeatedly in column. Especially, in order to avoid secondary pollution, the generated disabled cationic fly ash adsorbent can be reused to produce polymer concretes as a functional filler. The present work can provide new insight into the utilization of modified fly ash for treating wastewaters.

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.

Manufactured synthetic substances have been generally utilized as dyes by the material enterprises. Since a lot of various dyes are utilized by material ventures, wastewater released out of them represents a danger to the environmental factors. These dyes go into the encompassing water bodies as hued wastewater, except if debased appropriately. Miniature creatures can change over shaded colors to non-hued fluid under characterized natural conditions. In this examination, degrading dye capacity for blended consortia (Bacterial and parasitic) of Pseudomonas putida and Phanerocheate chrysosporium is read for manufactured color Reactive Red 198. Results show that blended consortia of Pseudomonas putida and Phanerocheate chrysosporium has a proficiency of 91% in decolorization and 87% in COD evacuation inside 3 days of dynamic condition.

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.

Reactive dye is widely used for cotton dyeing, but its low utilization results in vast amounts of colored effluent with high salinity discharge. Amino-modified Reactive Red 195/P(styrene-co-butyl acrylate-co-trimethyl(vinylbenzyl) ammonium chloride) nanospheres (Am-RPNs) are a kind of novel colorant that exhibit excellent dyeing ability for cotton fabrics and higher dye utilization than original reactive dyes. The colored polymer nanospheres demonstrated small size, high stability and dye content in the dispersion system when cationic polymer nanospheres were dyed at an optimal dye dosage of 100%. Transmission electron microscopy images showed that the polymer nanospheres have smooth spherical shapes. Am-RPNs with an average hydration diameter of 96.5 nm and zeta potential of −33.7 mV were fabricated after being modified with ethylenediamine at pH 11. Both analytical techniques, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, indicated the presence of –NH2 on the surface of Am-RPNs. The amino-modification mechanism of the Reactive Red 195/P(styrene-co-butyl acrylate-co-trimethyl(vinylbenzyl) ammonium chloride) nanospheres depended on the dyeing bath pH. The color depths of the cotton fabrics dyed with Am-RPNs reached up to 3.1 times higher than those with Reactive Red 195. Scanning electron microscopy images showed that Am-RPNs form stable deposits on the surface of the modified fibers. The cotton fabrics dyed with Am-RPNs possessed excellent rubbing and washing fastness, satisfactory light fastness, and desirable handle. This study provides an innovative method that employ Am-RPNs with high coloration performance to endow the cotton fabric with deep color and good colorfastness without using inorganic salt.

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...

The inert chemical structure of poly(ethylene) terephthalate (PET) prevents its dyeability with reactive dyes. In this study, the reactive dyeability of polyester fabrics after enzymatic surface modification with different lipases and cutinase was investigated. The reason for the hydrophilicity of the fiber after enzymatic treatment was thought to be functional groups produced after this process, but their peak intensities in Fourier transform infrared spectroscopy (FTIR) were low and shaded by other functional groups. Scanning electron microscopy (SEM) showed that the enzymatic treatment did not cause any surface damage. A slight staining (K/S = 0.30) of the PET fabrics with the reactive dye occurred after enzymatic treatments. Moreover, the fastness to washing and rubbing of the reactive dye stained fabrics were good to excellent.

The agricultural waste of orange peels (OPs) was utilized as a cheap biosorbent and then tested for its ability to treat the reactive red (RR) dye wastewater. Several experiments were done to get the equilibrium isotherm and kinetic-relevant data. In addition, several experimental factors such as solution pH, temperature, contact time, and initial RR dye concentration were studied, in light of their impact on the biosorption process. The utilized isotherm and kinetic models were evaluated by using the chi-square test and coefficient of determination parameters for their representation of real data. In addition, the obtained data of their biosorption capacities, at different conditions, were modeled by the artificial neural network (ANN) approach. The results of the isotherm study revealed that the experimental data can be best accounted by both the Langmuir and Temkin models, demonstrating that the RR molecules were sorbed to two or more different types of biosorption sites of OP. The kinetic study for determining the characteristics of the rate of diffusion demonstrated that the intraparticle diffusion process was not the sole rate-limiting step in the biosorption of the RR dye-OP couple. Furthermore, the biosorption process was chemisorption in nature, as the pseudo-second-order reaction proved to be the best representative model for the kinetic data. The outcome of modeling also assumed that using the ANN tool was useful to reproduce the data again and foretell the manner in which biosorption behaved. According to the results of the Langmuir model, it was found that the maximum OP uptake for the biosorption of the RR dye was up to 82 mg/g, observed at optimized values of the experimental parameters. Such prior results highlight that OP is an effective agent of biosorption in the elimination of RR dyes from polluted solutions, moreover, in a cost-effective manner.

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.

This study reflects the adsorption ability and usable of peanut shell-polyurethane type rigid foam for the removal of remazol orange RGB (RO-RGB) dye, a reactive dye, from aqueous solution. RO-RGB removal was studied for initial dye concentrations (10-150 mg l-1), pH values (3-9), and temperatures (20-60C) at various contact times. Dye removal increased with the increases in initial dye concentration and temperature while it was decreasing with an increase in pH. Maximum dye removal was determined to be about 98% under all the experimental conditions. Equilibrium data obtained were adapted to the Langmuir, Freundlich, and Temkin isotherm models, and it was seen that the adsorption obeyed the Freundlich isotherm model with determination of coefficient of r2 = 0.966. Kinetics data was found to be harmony with the pseudo-second kinetic order model (higher than r2 = 0.9908). As a result, it was determined that the polyurethane-type rigid foam produced from peanut shell could be used as an alternative to activated carbon and could easily be used as an adsorptive material to remove RO-RGB dye.

Reactive dyes have been identified to be highly hazardous pollutants because they were shown to be more toxic towards mammals than general organic compounds and organic dyes. Accordingly, for the first time, meso-architectured mercapto-modified siliceous hollow quasi-capsules (SH-SHQC) were prepared by a facile, ultrasonic-assisted, and one-step synthesis protocol. Adsorptive removal of rhodamine B (RhB) and methylene blue (MB) onto SH-SHQC in a batch system has been investigated. Isotherm results agreed very well with the Langmuir equation for both dyes. The maximum adsorption capacity of SH-SHQC for RhB and MB was determined with the Langmuir equation and was found to be 147.06 and 119.05 mg g−1 at 298 K, respectively (pH: 6.0 for RhB and 7.0 for MB; adsorbent dosage: 15.0 mg; the volume of the dye solution: 40.0 mL). Among different kinetic models, the pseudo-first-order equation was better fitted since experimental data agreed very well with theoretical data. SH-SHQC was shown to be a promising adsorbent for adsorptive removal of reactive dyes from aqueous solutions. To date, there has been no report on the adsorption of reactive dye cations by meso-architectured mercapto-modified siliceous hollow quasi-capsules prepared by an ultrasonic-assisted, one-pot, and sol-gel synthesis method.

Purpose The purpose of this paper is to analyze zero valent iron nanoparticles (NZVIs) by a novel green method, taken from Thymus vulgaris (TV) plant extract, were synthesized and applied to degrade reactive black 5 (RB5) azo dye. Design/methodology/approach The optimum conditions for the highest removal of RB5 dye were determined. Characterization of NZVIs was done by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The NZVIs were used for the removal of dye RB5, and the parameters affecting were discussed like pH, initial concentration, contact time and NZVIs dosage. Findings The characterization results of NZVIs by SEM, TEM, FTIR and XRD show that polyphenols, organic acids and proteins reduce not only the green synthesis of NZVIs but also the aggregation of nanoparticles. The maximum dye removal efficiency of 99.6 per cent occurred at pH 4, NZVIs dose of 600 mg/L, and contact time of 5 min. The adsorption of RB5 dye onto the NZVIs surface and scavenging of the azo bond (−N = N) by the strong reduction of NZVIs were the proposed mechanisms for dye removal. The application of NZVIs to treat wastewater containing reactive dye shows high degradation efficiency. Research limitations/implications The findings may greatly benefit the application of the NZVIs taken from Thymus vulgaris (TV) in the fields of dye adsorption. Practical implications The present study is novel because it incorporated the morphological and structural properties of the synthesized NZVIs using a native plant of Iran and studied the capability of green-synthesized NZVIs to remove RB5 as a water contaminant. Social implications The native plant presented here can be developed for reduced environmental pollution before discharge to accepted water. Originality/value The NZVIs is prepared via green-synthesized method, which is prepared with leaves of TV. There are two main innovations. One is that the novel NZVIs is prepared successfully by native plant via green-synthesized method. The other is that the optimized conditions were obtained for the removal of RB5 dye as a water contaminant. Furthermore, to the best of our knowledge, no study has ever investigated the removal of RB5 by NZVIs produced using a native plant in Iran.

Cumin seeds extract containing plant polyphenols was used as a reducing agent forthe preparation of iron-based magnetic nanoparticles. Then, functionalised magnetic nanoparticles (FMNPs) and chitos...

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.

The extensive discomfort in the expulsion of toxic pollutants even at mild concentrations has demanded the need for prompt methods for the evacuation of dyes and heavy metals. The effective method for depuration of dye from the effluent is by sorption. Chitosan is a bio‐polymer which is gaining an increasing interest as one of the sorbents. It was obtained from the crab shells by undergoing several chemical processes and used as an adsorbent for dye, metal removal and also for pharmaceutical purposes. Cross linking it with other co polymers will increase the capacity of adsorption to a maximum level. Fish scales are considered to be a major waste in the food industry and since it takes a long time for decomposing it is considered to be one of the pollutants. Hence it is utilised by converting it into activated carbon by preliminary treatment and into a muffle furnace. The obtained activated carbon is combined with chitosan by using a cross linker and utilised for adsorption mechanism. To analyse the effect of chitosan cross linked with activated carbon obtained from fish scales in adsorption of dye Reactive Blue 9 (RB9) to evaluate the adsorption studies, kinetics, mass transfer studies, thermodynamics of the bio adsorbent.

A new bio-adsorbent to remove reactive dyes from textile effluent was investigated in the present study. The adsorbent was the leaves of locally available hogla plant (Typha angustata). Initially, sunfix yellow, a reactive dye widely used in textile effluents, was used to check the removal efficiency in terms of contact time, pH of dye solution and adsorbent dosage. Complete removal (100%) of dye was achieved at adsorbent/dye ratio of 2300:1 at pH 10 with 180 minutes contact time. The adsorbent was then applied to deep colored, raw textile wastewater samples and it was found that 2.3 g of adsorbent was able to convert 100 mL of deep colored wastewater to transparent water at pH 10. Additionally, treatment by the adsorbent resulted in significant decreases in pH, BOD, COD, TS, TDS and TSS of wastewater, while improving the DO level.