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Chemical stripping adversely affects the quality of cotton fabric due to prolonged exposure to harsh chemicals. High temperatures also affect the surface and tearing characteristics of recycled cotton. Microwave-assisted stripping is a viable approach to addressing these problems, requiring less time, energy, and chemical consumption. Furthermore, utilizing a microwave-absorbing molecule that assisted the heat generation, multiple treatment methods were applied to remove the dye reactive turquoise CLB from cotton fabric. In the reductive process, pretreatment with sodium citrate as a microwave absorber showed 94.8% stripping efficiency, while in the meta-treatment, stripping efficiency was 96.2%. In the conventional stripping procedure, 75.7% stripping efficiency was observed, much lower than microwave absorber stripping with an absorber. Moreover, FTIR analysis of treated and untreated fabrics confirmed the removal of Reactive Turquoise CLB from the cellulosic structure. The quality assurance parameters, weight loss, and tearing strength assure the performance of developed methods by showing higher tearing strength and negligible weight loss compared to conventional methods. [ABSTRACT FROM AUTHOR]

This study focuses on the improvement of the dyeability of cellulosic fibre with reactive dyes using a sustainable approach. A previously reported organic compound containing two epoxide rings, N1, N1'-(ethane-1,2-diyl) bis(N2-(oxiran-2-ylmethyl)ethane-1,2-diamine) (AXL-2) was employed as a cross-linker to the cotton fabric. AXL-2 was synthesized by reaction of epichlorohydrin (ECH) with triethylenetetramine (TETA). Reactive dyeing generates the most problematic effluent containing 20–50% dye in hydrolyzed form (due to the use of alkali in the dyeing process) along with large amounts of inorganic salts. Cotton fabric makes covalent interactions with AXL-2 that subsequently binds with the dye molecule containing free NH2 or OH groups in acidic conditions rendering efficient dyeing in the absence of alkali and salts. ESI-mass spectrometry and ATR–FTIR spectroscopy were used to characterize the synthesized compound, while the treated cotton fabric was characterized by ATR–FTIR and SEM–EDX. Dyeing properties of AXL-2 treated cotton fabrics were studied by measuring their K/S values, % exhaustion, % fixation, and % total fixation. Color difference between treated and untreated fabrics (DE) was evaluated using CIE lab system that exhibited excellent color depth on the AXL-2 treated cotton fabric compared to pristine cotton fabric. Color fastness properties of the dyed fabrics were also studied. No significant change in the absorbency and thermal stability of the fabric was noticed after treatment. The tensile strength of the treated cotton fabric before dyeing (TC) was reduced by 7.6% in warp and 3.5% in weft directions as compared to untreated cotton fabric (CC). However, the treated cotton fabric had lesser reduction in the strength warp-wise compared to untreated cotton fabric after dyeing along with an increase in the strength weft-wise. The novel dyeing method of treated cellulosic fibre by reactive dyes renders a sustainable and eco-friendly approach. [ABSTRACT FROM AUTHOR]

The article discusses the development of a camouflage uniform production system for civilian use with an emphasis on survival and hunting. Effective camouflage requires precise reproduction of the colors, textures, and patterns of specific landscapes, increasing hunting success and unnoticed movement. The technological process of fabric dyeing, necessary for the production of high-quality camouflage uniforms, includes fabric preparation, dyeing and strict quality control.. Fabric preparation includes cleaning, soaking, bleaching, and mercerization to ensure uniform dye absorption and durability. Dyeing methods vary by fabric type, with reactive dyes for natural fibers and disperse dyes for synthetics. Quality control includes visual inspections and tests for colorfastness under various conditions. Advanced dyeing techniques such as continuous dyeing, spray dyeing, stencil dyeing and digital printing have been analyzed to offer certain advantages. Machines like the Mimaki TX300P handle various fabric widths with high precision and reliability, enhancing efficiency. Automation using the Mimaki TX300P streamlines the dyeing process, optimizing ink consumption and integrating fabric loading, printing, and cutting systems. A customer relationship management system further automates garment creation, enhancing design, order management, and quality control. Tools like CLO3D enable detailed 3D modeling and accurate pattern reproduction. The customer relationship management system coordinates production stages and provides precise paint usage recommendations, ensuring efficient resource management and high-quality outcomes. In conclusion, developing and automating fabric dyeing processes for camouflage uniforms involve advanced technologies and meticulous quality control, ensuring durable, colorfast camouflage clothing that blends effectively into natural environments for civilian use. [ABSTRACT FROM AUTHOR]

In this research, a photocatalytic reactor made of quartz was designed and built. Then modified ZnO photocatalysts with different percentages of Ag and Zr were made by combustion method and using the microwave. Photocatalytic experiments showed that nano photocatalysts with a mass ratio of 0.093 Ag and 0.04 Zr are more efficient. The characteristics of this catalyst were evaluated by XRD, SEM, and FT-IR analyses. Then the photocatalytic activities of ZnO-Ag-Zr in the degradation of reactive red dye 198 were investigated and the effective factors such as pH of the solution, amount of catalyst, and initial concentration of the solution were investigated. Experiments showed that the optimal conditions for decolorization of the dye at a concentration of 20 mg/liter are: pH=10 and the amount of catalyst is 0.3 g/l, and in these conditions, the decolorization rate is above 92%. Also, the study of the kinetics of the mentioned reaction showed that the removal rates of Reactive Red 198 dyes are in good agreement with the pseudo-firstorder Longmire-Hinshelwood equation, and therefore, the kinetic parameters were determined using this model. [ABSTRACT FROM AUTHOR]

Ultrafine polyamide/polyurethane synthetic leather (UP/PSL), with a highly natural leather‐like appearance and touch, is widely used in many leather commodities. Generally, acid dyes, which are mostly used for dyeing UP/PSL, exhibit poor colour fastness. While, reactive dyes are well‐known for their good colour fastness. However, reactive dyes are not used to dye UP/PSL because they are water‐soluble and cannot stain the polyurethane (PU) in UP/PSL. In this study, five low water‐soluble reactive dyes with good affinity for both polyamide (PA) and PU were synthesised and characterised using ultraviolet‐visible and infrared spectroscopy, and mass spectrometry. All low‐water‐soluble reactive dyes were monoazo dyes with only one sulfonic group and two different functional groups. The reactive dyes were used to dye UP/PSL at 98°C and fixed at 90°C with 7‐azatridecane‐1,13‐diamine as a crosslinking agent. For comparison, Eriofast Red‐2B (ER‐2B) was used to dye UP/PSL using a special dyeing procedure. ER‐2B showed severe issues related to low utilisation and uneven dyeing, whereas the five low water‐soluble reactive dyes exhibited better performance than ER‐2B. Both the exhaustion and fixation of dyes 1 and 4 exceeded 90.0% when the dosage was less than 3.0% owf (on weight of fabric). In addition, they exhibited good levelling. The washing fastness of the five reactive dyes was excellent and higher than grade 4. The dry rubbing fastness was higher than grade 3‐4. Therefore, UP/PSL can be satisfactorily dyed using the reactive dyes with a solubility of less than 1.0 g/L and meet the requirements of daily life applications. [ABSTRACT FROM AUTHOR]

Textile industries release major fraction of dyestuffs in effluents leading to a major environmental concern. These effluents often contain more than one dyestuff, which complicates dye degradation. In this study ten reactive dyes (Reactive Yellow 145, Reactive Yellow 160, Reactive Orange 16, Reactive Orange 107, Reactive Red 195, Reactive Blue 21, Reactive Blue 198, Reactive Blue 221, Reactive Blue 250, and Reactive Black 5) that are used in textile industries were subjected to biodegradation by a bacterial consortium VITPBC6, formulated in our previous study. Consortium VITPBC6 caused single dye degradation of all the mentioned dyes except for Reactive Yellow 160. Further, VITPBC6 efficiently degraded a five-dye mixture (Reactive Red 195, Reactive Orange 16, Reactive Black 5, Reactive Blue 221, and Reactive Blue 250). Kinetic studies revealed that the five-dye mixture was decolorized by VITPBC6 following zero order reaction kinetic; Vmax and Km values of the enzyme catalyzed five-dye decolorization were 128.88 mg L−1 day−1 and 1003.226 mg L−1 respectively. VITPBC6 degraded the dye mixture into delta-3,4,5,6-Tetrachlorocyclohexene, sulfuric acid, 1,2-dichloroethane, and hydroxyphenoxyethylaminohydroxypropanol. Phytotoxicity, cytogenotoxicity, microtoxicity, and biotoxicity assays conducted with the biodegraded metabolites revealed that VITPBC6 lowered the toxicity of five-dye mixture significantly after biodegradation. [ABSTRACT FROM AUTHOR]

Leather dyeing is a critical step in leather manufacturing, as it is responsible for providing leather products with an eye-catching visual aspect and adequate quality properties to meet customers' expectations. This step is becoming more and more challenging as the leather industry advances hand in hand with new environmentally friendly policies and regulations to achieve a safer and healthier planet by replacing the highly polluting Cr-based leather tanning technology with greener alternatives. As a result, achieving high-performance dyeing of organic chrome-free leather is one of the bottlenecks for the sustainable development of the leather industry. Herein, we propose a novel strategy to fabricate an isocyanate-based oligomeric dye (IBD) with high coloring capabilities (component content higher than 62.8%) based on toluene 2,4-diisocyanate and reactive red dye 180. This material has been tested for the dyeing of biomass-derived aldehyde (BDA)-tanned leather with excellent outcomes. The experimental results showed that the crust leather dyed with our novel IBD dyeing agent had higher color fastness and better fullness than the leather dyed with conventional anionic (CAD) or reactive red 180 (RRD-180) dyes. These excellent and promising results open new avenues in manufacturing high-performance organic Cr-free leather products and help to ensure the sustainable transition of the leather industry from Cr-based leather tanning to more sustainable alternatives, maintaining the final quality of the leather products. [ABSTRACT FROM AUTHOR]

The optimization of pretreatment parameters is one of the most important factors for the successful dyeing of textile materials. The aim of this study was to investigate the most effective way of pre-treating cellulose based lyocell knitted fabric in order to achieve an optimal result when dyeing it with reactive dyestuffs. This research investigates the effects of pretreatment by exhaust method on lyocell knitted fabric, which is analyzed using five different recipes. Pretreatment techniques that are being used are mild pretreatment, hot wash without detergent, hot wash with detergent, causticization, and hot wash with causticization. Pretreated and untreated lyocell fabric is dyed with bi-functional reactive dyestuffs in a shade of 1%, to produce color. Three key factors are considered in this research work: optimum pretreatment technique, causticization time selection, and causticization concentration selection. In order to optimize the pretreatment technique, 16 trials are performed by varying the time and concentration. Compared to other pretreatment techniques, causticization is the best for dyeing lyocell fabric with reactive dyes. Additionally, causticization treatment is observed to have the best performance on lyocell fabric when applied for 30 min. The optimum concentration of NaOH for causticizing lyocell fabric is 3 mol/l, as determined by the results. This assessment of results is done based on four factors such as K/S value (color strength), strength loss %, weight loss % as well as pilling test results. [ABSTRACT FROM AUTHOR]

The grafting of cotton fabrics with diallyldimethylammonium chloride was studied. The objective was to improve reactive dye adsorption and antibacterial properties. The cotton fabric was modified with the diallyldimethylammonium chloride at room temperature using the redox initiator system of potassium persulfate as an initiator and N,N,N′,N′-tetramethylethylenediamine as an accelerator. It was found that the nitrogen content of the cationized cotton fabrics increased with an increase in the diallyldimethylammonium chloride concentration and stayed constant at a concentration of 40% (v/v). The adsorption of the reactive dyes on the cotton fabrics was investigated. The contact time of the reactive dye adsorption on the modified cotton fabrics reached equilibrium at 30 min. The dye adsorption properties of the modified cottons depended on the concentration of the diallyldimethylammonium chloride, dyes concentration, chemical structure, and molecular weight of the reactive dyes. By grafting the fabrics with the diallyldimethylammonium chloride, the cotton fabric's antibacterial function was also enhanced. [ABSTRACT FROM AUTHOR]

Tussah silk is one of the most widely used wild silks. It is usually dyed with acid dyes, despite the shortcoming of poor wet fastness. Reactive dyeing is a good solution to this problem. In our work, sulfatoethylsulfone (SES), sulfatoethylsulfone/monochlorotriazine (SES/MCT), monochlorotriazine (MCT), and bis(monochlorotriazine) (Bis(MCT)) dyes were used to dye tussah silk. All of these dyes showed lower exhaustion and fixation on tussah silk than on mulberry silk under alkaline conditions. Among them, SES dyes were more applicable, with a fixation of 70–85% (at 4%owf dye) at 90 °C when using sodium bicarbonate as an alkali. SES dyes also showed a rapid fixation speed. The dyeing of tussah silk required lower sodium bicarbonate dosage, the use of more neutral electrolytes, and a higher dye quantity to achieve deep effects compared to mulberry silk. Dyed tussah silk displayed lower apparent color depth and brilliance than dyed mulberry silk. The neutral boiling dyeing of tussah silk with SES dyes exhibited higher exhaustion, higher fixation (82–92% at 4%owf dye), and a slower fixation speed compared with alkaline dyeing. Furthermore, in this dyeing method, SES dyes showed higher and more efficient fixation on tussah silk than on mulberry silk. All dyed tussah silk had excellent color fastness to soaping. [ABSTRACT FROM AUTHOR]

The textile industry is known for its excessive water consumption and environmental impact. One of the major challenges it faces is managing pollution generated by dyes, particularly bifunctional dyes, such as sumireact supra yellow s-hbu, with a red appearance and sumifix supra lemon-yellow e-xf, with a yellow appearance. This study aimed to investigate the decolorization kinetics of synthetic solutions of said bifunctional dyes, which comprise triazine and vinylsulfon. We conducted various tests, including modifications of pH, the addition of TiO2 P-50 nanoparticles, exposure to solar radiation, limited contact with oxygen, and eolic agitation. The initial solutions had a concentration of 1000 ppm of textile dye. The study showed that the reaction order for the "red" solutions in the R6 and R9 reactors and all the yellow solutions was ½. The concentration of nanoparticles and pH had a significant impact on the reaction rate. The yellow solutions with a concentration of 800 ppm and pH levels of 3.15, 4.13, and 2.25 demonstrated 100% color discoloration, followed by solutions with a concentration of 400 ppm and pH levels of 3.15, 2.25, and 4.13. The analysis of variance confirmed the reaction rate constants for the yellow solutions and emphasized the significance of pH in this process. [ABSTRACT FROM AUTHOR]

In a traditional water-based dyeing system, large amounts of salts and water are consumed. However, a non-aqueous media dyeing system achieves salt-free and less-water dyeing. In a non-aqueous media dyeing system, a small amount of water is used, which may affect the aggregation morphology of the dyes. The molecular dynamics of reactive dyes on the surface of cotton fibers were investigated. The results showed that the color depth of dyed cotton fabric did not change much when the dosage of salt was below 5.2% o.w.f. However, continuing to increase the amount of salt could influence the dyeing level of dyed fabric. The diffusion coefficient of dye was 0.3044 × 10−5 cm−2/s when there was no salt in dyeing system. But it was decreased by 14.03% and 16.62% when the salt concentration was increased from zero to 5.2% and 13% o.w.f., respectively. When the concentration of sodium sulfate was zero, the dye molecules in the solution displayed in the form of unimolecular molecules and dimers. However, reactive dyes mainly existed in the form of trimers and polymers when the concentration of sodium sulfate was above 5.2%. When there was no salt in the less-water dyeing system, the van der Waal energy between fiber and dye was 131.29 kJ/mol, but it was increased to 382.92 kJ/mol when the dosage of sodium sulfate was 5.2%. Therefore, with the increase of sodium sulfate dosage, the color depth of the dyed fabric changed little, but the level of dyeing property became poorer. [ABSTRACT FROM AUTHOR]

We investigated the removal of the reactive dye Remazol Red from segregated dye bath with an integrated physical-biological approach combining easy applicability and fast kinetics of the sorption process with intrinsic sustainability of biological treatments. The proposed process consists in a first step dye removal by sorption on a cheap commercial polymer (Hytrel 8206) followed by anaerobic polymer bioregeneration. Excellent dye removals were achieved (up to 100%) under acidic conditions with fast kinetics (in most cases, 4 h are sufficient to reach efficiencies ≥ 80%). Experimental sorption data were well correlated with the Freundlich isotherm and pseudo-first-order kinetic model. The sorption process was optimized with response surface methodology. Practically complete removal was achieved with pH of the solution, initial dye concentration and polymer-to-water ratio equal to 4, 50 mg/L and 8.03% v/v, respectively. High desorption performance under neutral conditions makes Hytrel suitable for bioregeneration in a two-phase partitioning bioreactor. Polymer bioregeration reached 82% efficiency with the added value of achieving effective biodegradation (> 50% in 4 days) of the dye desorbed from the polymer. The study demonstrated the two-step process feasibility, which is characterized by the advantage of employing a cheap commercial polymer and has the potential of achieving complete dye mineralization. [ABSTRACT FROM AUTHOR]

Agricultural wastes are potential sustainable adsorbents since they are available in large quantities, are low-cost, and may require little or no treatment, in some cases. In this study, several fruit peels, such as banana, orange, and pomegranate, were collected from local markets and prepared by a simple and eco-friendly method and used as natural adsorbents for the removal of both anionic (Reactive Red 120 (RR120), Reactive Black 5 (RB5), Remazol Brilliant Blue R (RBBR)) and cationic Methylene Blue (MB) dyes found in wastewaters. Many industries, such as leather and textiles, can release huge amounts of synthetic dyes into the wastewater during dyeing processes. These are one of the most important pollutants of water pollution as they cause enormous damage to the water body and also affect the health of organisms due to their toxicity and carcinogenicity. The search for a sustainable and at the same time efficient material for the removal of a wide variety of dyes is the innovation of this work. These peels were prepared by washing, drying, grinding, and finally sieving, under natural sustainable conditions. Porosometry (BET analysis), FTIR, SEM/EDS, and XRD techniques were used to characterize the fruit peels before and after the adsorption process. Factors affecting the adsorption of dyes (adsorbent dosage, pH solution, initial concentration of dyes, contact time, and temperature) were investigated. According to the results, in terms of the effectiveness of fruit peels as (natural) adsorbent materials, for anionic dyes, 5.0–6.0 g/L of banana or orange dry peels was sufficient to remove near or even more than 90% anionic dyes at pH 2.0, and 4.0 g/L was sufficient to remove 98% of cationic MB dye at pH 9.0. Similar amount of pomegranate peels had lower efficiency for anionic dyes (50–70%), while cationic MB was still efficiently removed (98%) at pH 9.0. Moreover, the adsorption process in all cases was found to better fit to pseudo-second-order model, in comparison to pseudo-first-order model. According to isotherms, Freundlich model fitted better in some cases to the equilibrium data, while the Langmuir model in others. Finally, this study demonstrates the viability of reusing the banana, orange, and pomegranate peel adsorbents for eight, four, and five cycles, showing a gradual reduction of around 50% of their effectiveness. [ABSTRACT FROM AUTHOR]

The study investigated the effect of modifying rapeseed husks with ammonia and epichlorohydrin on their sorption capacity against anionic reactive dyes: Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84). Its scope included sorbents characterization (FTIR, pHPZC), determination of pH influence on the sorption effectiveness of dyes, the adsorption kinetics of dyes, as well as the maximum sorption capacity. The study proved that the reaction of rapeseed husk biomass with ammonia can lead to its amination, namely to the introduction of amine functional groups into the material's structure. The sorption effectiveness of RB5 and RY84 on the tested sorbents was the highest in the pH range of 2–3. The dye sorption kinetics was well described by the pseudo-second-order model. The sorption equilibrium time ranged from 90 to 180 min, and depended on the initial concentration of dyes and the number of amino groups on the sorbent's surface. The most efficient of the sorbents tested were rapeseed husks pre-activated with epichlorohydrin and then aminated with ammonia. Their sorption capacity determined for RB5 and RY84 was 135.83 mg/g and 114.23 mg/g, respectively, which was 794% and 737% higher than that of the non-modified husks. [ABSTRACT FROM AUTHOR]

The use of residual microbial biomass from various industries in emerging pollutant removal strategies represents a new area of research in the field. In this case, we examined how to remove reactive dyes from an aqueous solution utilizing a biosorbent made of residual biomass from immobilized Saccharomyces pastorianus (S. pastorianus) in a polymer matrix using a dynamic system. Fluidized bed column biosorption investigations were carried out on a laboratory scale. Brilliant Red HE-3B was chosen as the target molecule. The main parameters considered for this purpose were the flow rate (4.0 mL/min; 6.1 mL/min), initial pollutant concentration (51.2 mg/L; 77.84 mg/L), and biosorbent mass (16 g; 20 g). The experimental data of the fluidized bed study were evaluated by mathematical modeling. The Yoon–Nelson, Bohart–Adams, Clark, and Yan models were investigated for an appropriate correlation with the experimental data. An acceptable fit was obtained for a flow rate of 4 mL/min, an initial pollutant concentration of 51.2 mg/L, and a biosorbent amount of 20 g. The obtained results indicate that the biosorbent can be used efficiently in a dynamic system both for the removal of the studied dye and in extended operations with a continuous flow of wastewater. As a conclusion, the investigated biocomposite material can be considered a viable biosorbent for testing in the removal of reactive dyes from aqueous environments and creates the necessary conditions for the extension of studies toward the application of these types of biosorbents in the treatment of industrial effluents loaded with organic dyes. [ABSTRACT FROM AUTHOR]

A starch-based adsorbing-flocculating bifunctional material St-A/F is prepared via graft copolymerization with two cationic monomers DMC and DMDAAC, using a safe and clean Fenton initiating system. 13C NMR, XRD, SEM and BET are used in characterization of chemical construction and physicochemical property for the product. St-A/F has double functions of adsorbing and flocculating; it can remove hydro-soluble reactive and direct dyes, and insoluble disperse dyes simultaneously. In adsorption study, the removal ratio (RR) of direct dye 4BS and reactive dye KE-4B were 92.06 and 94.13%, respectively. The adsorption behaviors have higher fitting degree to pseudo-second-order kinetic and Langmuir isothermal model than pseudo-first-order and Freundlich isothermal model. In flocculation study, the RR of St-A/F was recorded above 93.91% to three disperse dyes. St-A/F has significantly increased Zeta potential and isoelectric point (pI 9.08). St-A/F can cause destabilization and aggregation to negatively charged disperse dye particles, via charge neutralization and bridging effects, using its positively charged graft branched chains. St-A/F can simultaneously remove soluble and insoluble pollutants, so it considered to have great advantage in treatment for practical textile printing and dying wastewater with complicated composition. [ABSTRACT FROM AUTHOR]

In this research, low-priced bio-chars produced from biomass waste (fiddle-leaf fig seed) via physical and chemical activation processes were applied for selective removals of iodine and reactive dyes. The adsorption natures and capabilities were systematically considered from isotherms, kinetic and thermodynamic parameters. As achieved results, activated bio-char (ABC) prepared via phosphoric activation and carbonization at 400 °C for 2 h presented good capabilities for adsorptions of iodine (qmax = 420.47 mg/g) and reactive red 22 (RR22, qmax = 15.17 mg/g). The fast adsorption natures of iodine and RR22 using each adsorbent exhibited monolayer physisorption, which were identified by Langmuir, Dubinin–Radushkevich, Redlich–Peterson, Toth and pseudo-second order, while intra-particle diffusion with 2 steps could be obtained from Weber–Morris model. Thermodynamic nature also displayed that iodine and reactive dye adsorption procedures were endothermic and spontaneous styles, supporting by standard enthalpy/entropy/Gibbs free energy at temperature range about 303–328 K. Moreover, the capability for selective removal of wastewater models (mixed dyes) over all adsorbents was in order of reactive blue 19 (RB19) > RR22 > reactive yellow 3 (RY3). This work methodically focused on adsorption manners of dye molecules using low-priced bio-char and gave possible/green way for wastewater treatment under practical process. [ABSTRACT FROM AUTHOR]

Developing reusable, sustainable and long term storable bioremoval technologies is essential for removal of heavy metals and reactive dyes in industrial wastewater. Clavibacter michiganensis (C. michiganensis) having bioremediation property was selected for attachment, and polysulfone (PSU) was selected as the polymer matrices for the electrospinning of nanofibrous webs. For this approach, polysulfone nanofiber mats (PSU-NFMs) were produced by electrospinning, followed by attachment of bacteria onto nanofiber mats and a subsequent used in the removal of Cr(VI) and reactive dye. The efficient Cr(VI) removal with 100% yield was achieved within 24 hours (10 ppm) with bacteria attached nanofiber mats. Also, nano bio-composite mats decolorized 100% of Reactive Blue (RB, 20 ppm) within 13 h. Furthermore, the prepared bacteria attached to PSU-NFMs showed storage stability at 23 ± 2° and 4° for 30 days with efficient removal yields and PSU-NFMs found as potentially storable for keeping attached bacterial cells alive. Finally, the reusability of bacteria attached to PSU-NFMs were determined after five cycles for both pollutant and 70.3% and 51.8% of the Cr(VI) and dye removal capacities were obtained. It was expected that the bacteria attached to PSU-NFMs could be a potential application in wastewater treatment. [ABSTRACT FROM AUTHOR]

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In this study, a cross-linked chitosan-epichlorohydrin/nanosilica (CS-EPH/NSi) bionanocomposite was prepared using a simple two-step process. First, functionalization of chitosan with nanosilica followed by crosslinking process with epichlorohydrin. The CS-EPH/NSi bionanocomposite's adsorption property toward the removal of reactive orange 16 (RO16) dye was evaluated. The adsorption process of RO16 by CS-EPH/NSi was optimized using Box-Behnken design (BBD). The desirability function results revealed that the highest removal of RO16 (96.32%) is achieved at the following experimental conditions: solution pH of 4.26, dosage of CS-EPH/NSi = 0.089 g/100 mL, and contact time of 9.69 min. The Langmuir isotherm model was found to describe the equilibrium behavior of the monolayer adsorption process at 25 °C. The kinetics data of RO16 adsorption by CS-EPH/NSi were appropriately described by a pseudo-second order model, which suggests that the adsorption process occurs via chemisorption. The high adsorption capacity of CS-EPH/NSi for RO16 (110.2 mg/g) can be attributed to the electrostatic forces between the positively charged CS-EPH/NSi and the negatively charged RO16 anions, as well as n-π and H-bond interactions. Overall, this study demonstrates the potential of CS-EPH/NSi as an adsorbent for the efficient removal of textile RO16 dye. [ABSTRACT FROM AUTHOR]

Reactive dyes stand out for their bright shades, excellent fastness properties, and soft touch in the screen-printing process with cellulose. However, reactive dyes have a low affinity for cellulose. Therefore, this study aimed to apply the cationic agent 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) in the preparation of the reactive dye solution red 245, to improve the conduction of the screen-printing process and the fixation of the dye to fiber. In this process, a Box-Behnken Design was used to investigate the effect on concentrations of cationic agent (40, 60, and 80 g/kg), urea (75, 100 and 125 g/kg), and sodium carbonate (20, 30, and 40 g/kg). The study analyzed the paste pH, viscosity, zeta potential, color intensity, % penetration of prints, and dye concentration in the washing baths after the printing process. The study determined that the optimal levels for these factors were 60 g/L for the cationic agent, 100 g/L for urea, and 30 g/L for sodium carbonate. The optimization of the printing paste proved to be a great alternative to help in the color yield and penetration percentage of the prints, minimizing the use of urea, alkali, and cationic agents in the printing pastes. [ABSTRACT FROM AUTHOR]

As has been portrayed in the literature, the main proteins extracted from the seeds of Moringa oleifera Lam. have coagulant and clarifying potential in water treatment. However, when using them as coagulant agents, sludge formation occurs, which is an environmental problem. Thus, it was proposed to synthesize hydrogels from the main Moringa seeds proteins and use them as adsorbents. This work aimed to synthesize albumin hydrogels and globulin hydrogels and evaluate their efficiency as adsorbents to remove the reactive black 5 dye. Through FTIR spectrum it was possible to confirm that the synthesis of hydrogels occurred successfully. The kinetic data fit the pseudo‐second order model for both hydrogels. The equilibrium isotherms showed that adsorption occurs in multilayers, due to Freundlich fitting. The maximum adsorption capacity occurred at 298 K and was 1.19 mg g−1 for the albumin hydrogel and 10.06 mg g−1 for the globulin hydrogel. Through the results it is possible to state that globulin hydrogel was more favourable for adsorption since it has a more porous morphology and requires less mass compared to albumin hydrogel. [ABSTRACT FROM AUTHOR]

Dyes employed in many production cycles are characterized by high toxicity and persistence in the environment, and conventional wastewater treatments often fail to reach high removal efficiencies. Consequently, there is an increasing research demand aimed at the development of more efficient and sustainable technologies. A two-step strategy consisting of dye sorption followed by sorbent bio-regeneration is proposed here, with a special focus on the regeneration step. The objective of this study was to establish the best operating conditions to achieve regeneration of dye-loaded polymers and concurrently the ultimate removal of the dyes. To this aim, the bio-regeneration of the Hytrel 8206 polymer, used as a sorbent material to remove Remazol Red dye from textile wastewater, was investigated in a two-phase partitioning bioreactor (TPPB) under alternated anaerobic–aerobic conditions. Comprehensive analysis of operational parameters, including sorbent load and initial contamination levels, was conducted to optimize bio-regeneration efficiency. Experimental data demonstrated high regeneration efficiencies (91–98%) with biodegradation efficiencies up to 89%. This study also examines the biodegradation process to investigate the fate of biodegradation intermediates; results confirmed the successful degradation of the dye without significant by-product accumulation. This research underscores the potential of TPPB-based bio-regeneration of polymeric sorbent material for sustainable wastewater treatment, offering a promising solution to the global challenge of dye pollution in water resources.

Denim clothes are the must-have items of clothing around the world. This kind of fabrics is evolving with the increasing consumer demand in order to keep its place as a versatile article. In this context, this paper contributes to the development and dyeing of a new blend fabric made of cotton fibers and bicomponent polyester filaments (PET/PTT). A comparative study between the mechanical and thermal properties of this fabric and conventional fabrics has confirmed the great interest to use bicomponent (PET/PTT) filaments in the manufacture of denim fabrics; these bicomponent filaments allow to give to wearer the desired elasticity and comfort. For dyeing (cotton/bicomponent polyester filaments) blend fabric, three different processes, using reactive and disperse dyes, were tested and analyzed. These dyeing processes are: two-baths/two-phases, one-bath/two-phases, and one-bath/one-phase processes. In addition, in order to obtain uniform shades between cotton fibers dyed with reactive dyes and bicomponent polyester filaments dyed with disperse dyes, an ant colony algorithm was elaborated to predict the optimal dye recipes. By observing obtained results, the developed algorithm is very effective; it allows to find the combination of reactive dyes necessary to achieve the same shade obtained by the disperse dyes with very small color differences between the two components and without having to make corrections mainly for the one-bath/two-phases process. Indeed, dyeing using the two processes (two baths/two phases and one bath/two phases) presents the best values of color yield (K/S) with almost similar results (ΔECMC(2:1) < < 1). For the one-bath/one-phase process, it presents less significant results; We can observe ΔECMC(2:1) greater than 1 in certain shades. This is due to the strongly pH value (basic pH of 11) of reactive dyeing. [ABSTRACT FROM AUTHOR]

In this study, the facile removal of the chromium-complex-based reactive azo dye C. I. Reactive Black 8 (RB8) from model wastewaters by the co-action of alternative sorbents—biochar (BC) and bentonite (BT)—with ionic liquids such as benzalkonium chloride (BAC) or Aliquat 336 (A336) was studied. The experiments using model RB8-containing wastewater proved that the co-action of BAC with BC is the most promising method of RB8 separation from wastewater containing 1 g L−1 of RB8 dye. The application of 2 g L−1 BC in co-action with 1.5 g L−1 BAC or 1 g L−1 BT in co-action with 2 g L−1 BAC enables the removal of more than 98% of contaminant RB8 after 30 min of action. Similar removal efficiency (RE) was achieved using 40 g L−1 of powdered activated carbon (PAC) after 180 min of action. To reach the same RE using real RB8-containing wastewater, a four times higher dose of BC and a four times higher dose of BAC per gram of removed RB8 were required. The proposed mechanism of RB8 removal by the co-action of alternative sorbents with BAC comprises a parallel effect of (i) sorption, (ii) the formation of less polar ion pairs accompanied by their sorption on an alternative sorbent and (iii) the separation of used alternative sorbents covered with ion pairs. The removal efficiency of organic contaminant(s) from both model and real wastewater was evaluated by VIS spectroscopy applying the Lambert–Beer law and by the determination of chemical oxidation demand (COD) and/or adsorbable organically bound halogen (AOX) parameters. [ABSTRACT FROM AUTHOR]

Herein, magnesium–aluminum layered double hydroxides (Mg–Al-LDH) were synthesized by an environmentally friendly and economically promising hydrothermal technique for the adsorption of the dye reactive green 5 (RG5). To further enhance the RG5 dye adsorption capability of Mg–Al-LDH, their composites were designed by using low-cost Mangifera indica stone biomass (MISB). From their physiochemical properties evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy, they were found to display an irregular morphology along with the existence of various functional groups (including OH, C＝O, and C–H) on surfaces, enabling prepared biosorbents to be excellent candidates for adsorption. Batch adsorption trials were conducted to determine the comparative RG5 dye adsorption efficiencies of MISB, Mg–Al-LDH and the Mg–Al-LDH@MISB composite in an aqueous medium. The highest RG5 dye adsorption capacities recorded under optimized conditions (contact time: 90 min, pH: 3, adsorbent dosage: 0.05 g, initial RG5 dye concentration: 80 mg L−1 and temperature: 30 °C) for MISB, Mg–Al-LDH and the Mg–Al-LDH@MISB composite were 55.9 mg g−1, 68.4 mg g−1 and 73.5 mg g−1, respectively. The kinetic and isothermal study showed the best fit of the pseudo 2nd order and Freundlich models. Thermodynamic parameters illustrated the spontaneity of the process. In addition, the adsorbents as designed also possessed regeneration capability as evidenced by their RG5 dye desorption potential. Therefore, this research opens up new doors for the development of environmentally friendly Mg–Al-LDH by developing composites with economically feasible biomass for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

The present research employed immobilized Canna indica beads (CIBs) to obtain maximum degradation of highly toxic Reactive Blue Dye (RBD), predominantly used in textile industry. The CIBs were characterized using FTIR and SEM-EDX analysis. A batch adsorption study was conducted to measure the removal of harmful RBD dye. Different factors were examined in the biosorption technique to achieve the maximum level of toxic dye elimination, such as adsorbent-solute interaction time (5-120 min), solution pH (2-10), adsorbent dose (25 to 250 mg/100 mL), RBD concentration (50-250 mg/L), and temperature (30-60°C). Removal of 99.96% of RBD was successfully achieved at the optimum pH 7, RBD concentration of 50 mg/L, adsorbent dosage of 150 mg/100 mL, a temperature of 303 K, and 60 min of interaction time. The Langmuir isotherm and pseudo-second-order (PSO) kinetic model data have been found to be an ideal match compared to the Freundlich isotherm and pseudo-first-order (PFO) kinetic model. The maximum adsorption capacity onto CIBs biosorbent was found to be 70.49 mg/g. It was noticed that the chemical reaction occurred naturally and released heat during the process which denoted an exothermic reaction. These results shown that the adsorption of RBD removal is efficient using prepared adsorbent from Canna indica root tubers. Therefore, these CIBs could be used for other toxic dyes and heavy metals from industrial wastewater. [ABSTRACT FROM AUTHOR]

The applicability of Zeolitic Imidazolate-67, Modified by Fe3O4 Nanoparticles, was studied for removing textile dye Reactive yellow 105 from wastewater by adsorption method using response surface methodology (RSM). For the adsorption characterization of the adsorbent used in HE-4G dye adsorption, BET, FTIR, XRD, and SEM analyses were performed. The impacts of variables, including initial HE-4G dye concentration (X1), pH (X2), adsorbent dosage (X3), and sonication time (X4), the highest removal efficiency as 98%, 10 mg/L initial concentration, pH 6, 0.025 g adsorbent dosage, and 6.0 min time respectively. Adsorption equilibrium and kinetic data it, that data were for the Langmuir isotherm, pseudo-second-order kinetics, and maximum adsorption capacity (105.0 mg/g), respectively. Thermodynamic parameters indicated HE-4G dye adsorption is feasible, spontaneous and exothermic. Promising treatment capabilities of the ZIF-67-Fe3O4NPs have been during the comparative adsorption removal of HE-4G dye from DI water against spiked natural water samples and synthetic Na+, K+, Ca2+, and Mg2+ solutions. The observed outcome is the suitability of the artificial neural network model as a tool for mean square error, (MSEANN = 0.53, and R2 = 0.9926) for removing HE-4G dye. Results that ZIF-67-Fe3O4NPs, like being recyclable, and cost-efficient made it a promising absorbent for wastewater. [ABSTRACT FROM AUTHOR]

The widespread use of highly complex synthetic dyes like reactive dyes in the textile industry has some adverse environmental impacts and deserves close attention. Biological treatment of these effluents utilizing various species of bacteria with remarkable efficiency in dye removal is still considered promising. Our current study deals with immobilizing an isolated bacterial strain into calcium alginate (Ca/Alg) gel beads and using it to treat pernicious pollutants like synthetic dyes. A potential Reactive Blue 19 (RB19)‐degrading Enterobacter cloacae strain A1 was isolated from the Kashan textile industry and was characterized by 16S rDNA gene sequencing. The decolorization ability of strain A1 was assessed by time‐based studies using free bacterial cells/immobilized in Ca/Alg. Based on the results of the 16S rDNA gene sequencing, it appears that strain A1 belonged to E. cloacae, with a 99.74% similarity. The findings suggest that immobilized strain A1 accomplished maximum decolorization activity compared with the free cells. The immobilized strain could utterly decompose and decolorize 0.05 mg/mL of RB19 within 48 h, while the free bacterial strain decolorized RB19 within 5 days. Moreover, Ca/Alg gel beads can maintain their efficiency for over three decolorization cycles. Further infrared spectroscopy (FTIR) and gas chromatograph mass spectrometer (GC/MS) investigation declared complete RB19 decomposition on reaction products. Artemia salina was used to investigate the toxicity of dye and its degraded metabolites. The LC50 values signified the pure dye as very toxic with 0.01 mg/mL concentration, while after‐treatment products showed no toxic effect on larvae. This immobilization technique increased the applicability of bacterial strain for dye removal. It was beneficial for the decolorization of RB19 from textile wastewater due to a remarkable reduction in time. Notably, strain A1‐immobilized beads can maintain their activity for three consecutive decolorization cycles without a considerable decrease in efficiency. Practitioner Points: The remarkable capacity of immobilized Enterobacter cloacae strain A1 for Reactive Blue 19 (RB19) removalImmobilized A1 strain showed two‐fold higher removal than free one over 48 hA promising method for enhancing RB19 decolorizationDecolorization was due to degradation based on UV–Vis, FTIR, and GC/MS analysisNon‐toxic posttreatment products for Artemia [ABSTRACT FROM AUTHOR]

Nanoparticles of Zinc oxide (ZnONPs), has a variety of applications such as antibacterial property, water treatment for pollutant removal, and as catalysts for organic reactions etc. and have been synthesized utilizing a variety of approaches, including green synthesis, chemical precipitation, sol-gel, hydrothermal synthesis, and microwave-assisted synthesis. In the present work, easy and economically viable ZnONPs were synthesized utilizing Strobilanthes hamiltoniana (SH) leaf extracts. Phytochemicals form S. hamiltoniana act as agents for reducing and capping the metal oxide ions. A range of analytical and microscopic techniques have been used to investigate the physical and chemical properties of ZnONPs. At 360 nm, green synthesized SH-ZnONPs showed robust UV-Vis absorption. The nanosize, shape, and crystalline structure of SH-ZnO NPs were characterized using XRD and electron microscopy techniques. Using SH-ZnO NPs, the photocatalytic activity of textile dyes such as Reactive blue 220 (RB-220), Reactive blue 222A (RB-222A), Reactive yellow 145 (RY-145) and Reactive yellow 86 (RY-86) dyes showed degradation efficiency of 97.3%, 78.57%, 88.88%, and 83.33% after 320 min. ZnONPs exhibited remarkable antibacterial effectiveness against bacterial and fungal pathogens using the Minimum inhibitory concentration approach. Their MIC values were calculated, and free radical scavenging experiments showed antioxidant activity. The SH-ZnONPs were validated using HepG2 (IC50) cancerous cells lines and showed promising anti-cancer activity. These results revealed that SH-ZnO NPs had promising benefits that could be utilized as a viable therapeutic candidate. [ABSTRACT FROM AUTHOR]

Purpose: The main purpose of this study was to prepare the cotton fibers and cellulose powder by a layer of nano-crystalline-titanium dioxide (TiO2) using the sol-gel sono-synthesis method to clean the wastewater containing reactive dye. Moreover, TiO2 nano-materials are remarkable due to their photoactive properties and valuable applications in wastewater treatment. Design/methodology/approach: In this research, TiO2 was synthesized and deposited effectively on cotton fibers and cellulose powder using ultrasound-assisted coating. Further, tetra butyl titanate was used as a precursor to the synthesis of TiO2 nanoparticles. Reactive dye (red 195) was used in this study. X-ray Diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy were performed to prove the aptitude for the formation of crystal TiO2 on the cotton fibers and cellulose powder along with TiO2 nanoparticles as well as to analyze the chemical structure. Decoloration of the wastewater was investigated through ultraviolet (UV-Visible) light at 30 min. Findings: The experimental results revealed that the decolorization was completed at 2.0 min with the cellulose nano TiO2 treatment whereas cotton nano TiO2 treated solution contained reactive dyestuffs even after the treatment of 2 min. This was the fastest method up to now than all reported methods for sustainable decolorization of wastewater by absorption. Furthermore, this study explored that the cellulose TiO2 nano-composite was more effective than the cotton TiO2 nano-composite of decoloration wastewater for the eco-friendly remedy. Research limitations/implications: Cotton fibers and cellulose powder with nano-TiO2, and only reactive dye (red 195) were tested. Practical implications: With reactive dye-containing wastewater, it seems to be easier to get rid of the dye than to retain it, especially from dyeing of yarn, fabric, apparel, and as well as other sectors where dyestuffs are used. Social implications: This research would help to reduce pollution in the environment as well as save energy and cost. Originality/value: Decoloration of wastewater treatment is an essential new track with nano-crystalline TiO2 to fast and efficient cleaning of reactive dyes containing wastewater used as a raw material. [ABSTRACT FROM AUTHOR]

Reactive dyes in nylon dyeing have been associated with utilization inefficiencies despite their high color fastness. A potential solution to this issue involves combining the benefits of reactive dyes and milling acid dyes to obtain low-water-soluble reactive dyes (LWSRDs), which can stain and fix to nylon fibers under neutral conditions. To identify a suitable functional group for LWSRDs, six model dyes comprising one vinyl sulfone and five monochloro- s -triazines were prepared and reacted with glycine or hydrolyzed to simulate the fixation progress on nylon fibers. The results show that vinyl sulfone exhibited sufficient reactivity with glycine, and ∼3% hydrolysis over 90 min. Consequently, vinyl sulfone was considered a superior functional group for LWSRDs. Based on these results, four LWSRDs with monofunctional groups were synthesized and used for dyeing nylon 6 microfibers. Notably, these dyes exhibited fixation of >91% and demonstrated exceptional color fastness against washing and rubbing, exceeding grade 4. These results underscore the potential of LWSRDs as highly efficient and effective dyes for nylon, offering a solution to the limitations associated with conventional dyeing techniques. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the feasibility of extracting Acid Orange 7 (AO7), a complex reactive dye, from aqueous solutions using a stabilized emulsion liquid membrane (ELM) technique. The ELM formulation comprised tri-dodecylamine (TDA) as the extracting agent, kerosene as the diluting medium, and SPAN 80 as the surfactant. We systematically examined various experimental variables that affect the extraction of AO7. These variables included the concentrations of the extractant and surfactant, internal phase concentrations, the ratio of the membrane phase to the internal phase, the choice of diluting medium and its grade, stirring speed, treatment ratio, and the initial concentration of AO7. Furthermore, we investigated the impact of sodium chloride concentration in the external phase. Our research findings indicate that the optimal conditions for AO7 extraction using the ELM method were as follows: a TDA concentration of 3% (w/w), a SPAN 80 concentration of 9% (w/w), an oil-to-aqueous phase ratio (O/A) of 1:1, kerosene as the diluting medium, H2SO4 as the internal phase, a stirring speed of 200 rpm, a treatment ratio of 1:10, and an initial AO7 concentration of 10 mg/L. Under these precise conditions, an exceptional extraction efficiency of 98.49% was achieved in just 15 min. Under these carefully controlled conditions, an exceptional extraction efficiency of 98.49% was achieved in just 15 min. Consequently, the emulsified liquid membrane extraction process demonstrates significant potential as an advanced separation technique for removing hazardous dyes, particularly in dilute solutions. [ABSTRACT FROM AUTHOR]

The efficiency of desalination of reactive dye solutions with the addition of a fixed amount of mineral salt was evaluated using standard ion-exchange membranes in the electrodialysis (ED) process. Five reactive dyes (Reactive Orange 16, Remazol Brilliant Blue R, Reactive Orange 20, Reactive Black 5, Reactive Red 120), varying in molecular weight, were used in the study. The model solutions were prepared by varying the dye concentration (20, 50 and 100 mg/L) and adding mineral salt (2 g/L of NaCl) to each dye solution. It was observed that the salt was successfully separated from dye solutions with the efficiency of 97.6%-98.5%. The migration of dye molecules from diluate to concentrate compartments was negligible. The dye concentration in the concentrate compartments amounted to 0.6-0.85 mg/L, irrespectively of the process parameters. However, significant deposition of dye particles in the membrane matrix was noted. Around 26%-31% of the initial dye mass was adsorbed, and this effect was strongly influenced by the dye reactivity. It can be concluded that the ED process with standard ion-exchange membranes is quite a promising method for reactive dye and mineral salt separation. This will enable further usage of the obtained dye and salt streams in a variety of technological processes. [ABSTRACT FROM AUTHOR]

In this study, spent coffee grounds (SCG) were treated using sodium hypochlorite (NaClO) to remove organics. The NaClO-treated SCG was modified with 3-aminopropyltriethoxysilane (APTES) to improve its adsorption performance. To understand the characteristics of the prepared adsorbents, samples were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The pH edge, kinetic, and isotherm experiments were conducted to evaluate the adsorption performance of APTES-SCG for Reactive Black 5 (RB5), Reactive Orange 16 (RO16), and Reactive Yellow 2 (RY2). The pH edge experiments were carried out in the pH range of 2-12 at an initial dye concentration of 100 mg/L. The results showed that the dye uptakes on APTES-SCG increased with decreasing pH value. The adsorption experiments for kinetics confirmed that the equilibrium time was reached within 30 min at pH 2. The adsorption isotherm experiments were performed at initial dye concentrations of 30 to 300 mg/L, and the experimental data were well-fitted by the Langmuir model. The dye-loaded APTES-SCG was desorbed using 0.01 M NaOH solution and repeated adsorption-desorption experiments showed that APTES-SCG could be reused at least 3 times. [ABSTRACT FROM AUTHOR]

Present study focused on the green nanocomposites synthetization to treat textile wastewater and its reusability for agriculture crops. Punica granatum (leaves and peels) and biomass (almond shells, sugar cane bagasse, eggshells) are used for synthesis of zinc oxide nanocomposites (PGL-ZnO), copper nanocomposites (PGP-Cu) and iron nanocomposites (PGL-Fe). It is characterized by scanning electron microscope, Fourier-transform infrared spectroscopy, X-ray powder diffraction and Brunauer–Emmett–Teller. The highest adsorption efficiency of all synthesized nanocomposites was accomplished at pH 2 which is acidic, 0.01 g dose, 50 mg/L initial dye concentration and 90 min contact time at 40 °C temperature. The highest adsorption proficiency Punica granatum = 18 < Zinc Oxide nanocomposites = 78 < Iron nanocomposites = 65 < Copper nanocomposites = 85 mg/g of all synthesized nanocomposites was obtained. The model Freundlich showed good fitness results which indicate complex nanocomposites nature. The 1st order showed best results on fitness of isotherm on kinetic data and rate constants determined the best fitness of model. The negative value of ΔHo and ΔSo of nanocomposites exhibited the exothermic nature and decrease in disorderness of adsorption process for dye exclusion. When values of Δ G o is positive then the reaction is spontaneous. Desorption of acidic dye from maximum efficient nanocomposites was 99 mg/g using eluent. Hence, it was determined that these nanocomposites serve as the novel, feasible, cost-effective, ecofriendly, and bio recyclability for treating acid dye-containing wastewater. [ABSTRACT FROM AUTHOR]

Flavin mononucleotide (FMN) is a dye belonging to the flavin family. These dyes produce photosensitized degradation of organic compounds via reaction with the excited states of the dye or with reactive oxygen species photogenerated from the triplet of the dye. This article presents a new polymeric dye (FMN–CS) composed of the photosensitizer FMN covalently bonded to chitosan polysaccharide (CS). FMN–CS obtained has a molecular weight of 230 × 103 g mol−1 and a deacetylation degree of 74.8%. The polymeric dye is an environmentally friendly polymer with spectroscopic and physicochemical properties similar to those of FMN and CS, respectively. Moreover, under sunlight, it is capable of generating 1O2 with a quantum yield of 0.31. FMN–CS, like CS, is insoluble in basic media. This allows easy recovery of the polymeric dye once the photosensitized process has been carried out and makes FMN–CS a suitable photosensitizer for the degradation of pollutants in contaminated waters. To evaluate whether FMN–CS may be used for pollutant degradation, the photosensitized degradation of two trihydroxybenzenes by FMN–CS was studied. [ABSTRACT FROM AUTHOR]

Bi-functional reactive dyes from the Cold brand that have exceptional dyeing capabilities. The intermediate for bi-functional cold-brand reactive dyes is 3, 3'-Disulpho-4,4'-diamino diphenyl urea, which is synthesized through the interaction of one mole of urea aqueous solution with two moles of 1,4-diaminobenzene-2-sulphonic acid. In this bi-functional reactive dye system, urea was utilized as a bridge molecule to give the reactive dyes significant water solubility. Incorporating various cyanurated coupling components, different colors are produced. It has good dyeing properties and provides a wide spectrum of shades on various fibres. [ABSTRACT FROM AUTHOR]

The discharge of inorganic salts contained in the effluent of the dyeing of cotton using reactive dyes to the public environment has been under scrutiny. In the present investigation the flocculant polydimethyldiallyl ammonium chloride and an anion resin coded by D301 were employed for the purification of the exhausted bath discharged from the dyeing of cotton knitted fabrics using reactive dyes. Through the purification presented the exhausted bath is transferred to the concentrated inorganic salt solution and then reused in the next batch of dyeing. The process consists of the exhausted bath collection, precipitation formation by means of the flocculation and resin adsorption. The results indicated that the concentrated inorganic salt solution is suitable for all the reactive dyes employed in the dyeing of cotton. The K/S values, color evenness and color fastness properties of the dyed fabrics using the inorganic salt solution are basically the same as those using distilled water. The results also indicate that 72.0% of water and 71.1% of inorganic salt used for the dyeing can be saved when the inorganic solution is recycled four times, which means that the amount of the inorganic salt discharge to the environment can be reduced by 71.1%. [ABSTRACT FROM AUTHOR]

This study simulated actual dyeing wastewater in dyeing factories with three types of dyeing wastewaters from laboratory cotton fabric dyeing to investigate the effects of catalyst and oxidant peroxymonosulfate (PMS) concentrations, pH level, and temperature on dye degradation in wastewater and determine the optimal conditions for dyeing wastewater treatment accordingly. The results demonstrated that the optimal conditions varied with the reactive dyes. Specifically, the optimal oxidant PMS concentration for degrading Reactive Yellow and Reactive Blue was 0.6 g/L, and that for degrading Reactive Red was 0.4 g/L. The optimal pH level for degrading Reactive Red and Reactive Blue was around 7.0, and that for degrading Reactive Yellow was about 5.0. The activation energy of the degradation and the mineralization degree of the three dyes were also discussed. Reactive Blue showed greater activation energy (47.0 kJ/mol) and a higher mineralization degree (81% chemical oxygen demand removal) than the other two dyes under optimal disposal conditions. The Fe/N-codoped carbocatalyst loaded on carbon cloth exhibited desirable reusability and good stability for the degradation of the three dyes. Mechanisms involved in their degradation were analyzed through X-ray photoelectron spectroscopy, focusing on N species, Fe-N binding, and C=C and C–N active components in the Fe/N-codoped carbocatalyst. Electron paramagnetic resonance experiments demonstrated that both the radical and non-radical pathways were accountable for the degradation of the three dyes, primarily the non-radical pathway. This study may contribute to the application of activated PMS for practical dyeing wastewater treatment. [ABSTRACT FROM AUTHOR]

Due to the high stability of azo-type dyes, conventional treatment processes such as adsorption, flocculation, and activated sludge are not efficient for decolorizing wastewater effluents. An alternative to traditional wastewater treatment is photocatalysis, which has gained significant interest because research has shown it to be a viable and cost-effective process that uses sunlight as an inexhaustible energy source. In heterogeneous photocatalysis, a photocatalyst is required, such as TiO2, ZnO, composite materials, and, more recently, metal–organic frameworks (MOFs). MOFs, also known as "coordination polymers", exhibit photocatalytic properties and have been proven to be promising materials in the photocatalytic degradation of dyes. This study presents recent advances in using MOFs as photocatalysts to degrade recalcitrant contaminants like azo-type dyes. Recent advancements in developing photocatalysts based on MOFs are focused on two strategies. Firstly, the development of new MOFs composed of complex ligands or a mixed ligand system, and secondly, the synthesis of composite materials based on MOFs and metal oxides, metals, sulfides, nitrides, etc. Both strategies have significantly contributed to the search for new semiconductors to degrade some recalcitrate contaminants in wastewater. [ABSTRACT FROM AUTHOR]

Remazol Brilliant Blue dye (RBB) is a harmful dye from the textile industry that can damage the environment and aquatic life. Since RBB is impossible to degrade in water by primary and secondary wastewater treatment, its removal is a challenge. An excellent treatment procedure is urgently anticipated to avoid the pollution spreading into the environment. Moreover, rice husk waste (RH) in Malaysia is abundant and generally dumped into landfills. Turning the waste into a value‐added product such as biochar as an effective adsorbent material for treating water pollutants is one of the initiatives in realizing the circular economy agenda. This study develops an organic porous material of biochar from RH and assesses the kinetic of RBB adsorption onto the rice husk biochar (RHB) in aqueous solution. The production of RHB was optimized by pyrolysis procedure at various temperatures, times, and particle sizes. The removal of RBB dye by RHB was investigated at different exposure times from 0 to 120 min under 100 rpm shaken and immersed conditions. The reduction of RBB concentrations using different RHB pyrolysis conditions has also been investigated. The dye removal efficiency by RHB increased with time and the highest removal efficiency (69.3%) was achieved by the smallest particle size of RHB which was produced at the highest pyrolysis temperature of 400°C (RHB‐400). The total pore volume and BET surface area of RHB‐400 were found to be 50.4827 m2/g and 0.00875 cm3/g, respectively. The adsorption kinetic study signifies that maximum adsorption has been completed within 90–120 min depending on the RHB conditions whereas two kinetic models such as pseudo‐first order and pseudo‐second order kinetic models were utilized to fit the experimental data and the results are more consistent with pseudo‐second order kinetic models. This study revealed that RHB can be used as adsorbent materials for dye removals, yet it is economical, environmentally friendly, and sustainable. [ABSTRACT FROM AUTHOR]

In this study, gamma/H2O2 and UV/H2O2 treatment procedures were used for the degradation of five dyes including reactive red PB (R-24), reactive orange P3LN (O-13), reactive turquoise blue PG (B-21), reactive golden yellow H2R (O-12) and reactive lemon yellow C4G L (Y-15). The dye samples of 50 or 100 ppm concentration were treated with either gamma (0–10 kGy) or UV radiations in the presence/absence of H2O2. This treatment resulted in the elimination of chromophoric groups and degradation of dye molecule into low molecular weight fragments. The H2O2 treatment caused the generation of hydroxyl radicals which degraded the pollutants non-selectively by means of chain oxidation process. The treatment effectiveness was increased when H2O2, which was used in conjunction with UV or gamma radiation and the treated water quality, improved significantly. However, the gamma/H2O2 treatment was found to be the more effective and efficient method as compared to the UV/H2O2 treatment for the removal of dyes from the water. [ABSTRACT FROM AUTHOR]

Feasibility and applicability of rhamnolipid (RL) microbial biosurfactant-based reverse micellar non-aqueous system in different solvent medium for dyeing of cotton fabrics was investigated. In this study, several solvents, including heptane, octane, nonane, decamethylcyclopentasiloxane (D5), and paraffin liquid (PL), were chosen as the dyeing medium for non-aqueous dyeing of cotton fabrics with fixed dyeing parameters. The dyeing properties of these RL reverse micellar dyed samples in different solvent medium were examined and compared with the conventional water-dyed samples in terms of color yield (K/Ssum value), CIE L*a*b* values, color levelness and reflectance. Most non-aqueous RL reverse micellar dyed samples exhibited better color yield than conventional water-dyed samples. The surface morphology of dyed cotton samples and the dye encapsulation morphology in different solvent medium were observed by SEM and TEM, respectively. Most non-aqueous dyed samples yielded good to excellent levelness comparable to water-dyed samples. However, poor levelness and bad levelness were found for D5-and PL-dyed samples. Further modification of dyeing parameters would be needed to obtain the best dyeing results for D5-dyed and PL-dyed samples. [ABSTRACT FROM AUTHOR]

The present study describes the removal of reactive black 5 (RB5) using sodium carboxymethyl cellulose (NaCMC)-stabilized ZnO nanocomposite (ZnO-NaCMC)-incorporated polymer membranes (PMs). Herein, PMs were fabricated using six different polymers, such as cellulose triacetate (CTA), polysulfone (PSF), polyvinylidene fluoride (PVDF), polyphenylsulfone (PPSU) and polyetherimide (PEI). The permeation experiments, hydrophilicity, porosity, mechanical stability and ultrafiltration performance for RB5 dye removal and dye adsorption capacity of the membranes were tested for the as-prepared PMs. Water permeation studies revealed that ZnO-NaCMC nanocomposite-embedded PMs exhibit higher flux than all pristine polymer membranes. The incorporation of the ZnO-NaCMC nanocomposite into the dope solution increased the hydrophilicity and adsorption capacity of the PMs. In addition, the mechanical strength of the PMs was also enhanced owing to the presence of the ZnO-NaCMC nanocomposite in the membrane. PPSU/ZnO-NaCMC and PEI/ZnO-NaCMC PMs showed good colour rejection and appreciable water flux compared to pristine PMs. Moreover, the anti-fouling properties of the PMs have also been enhanced by adding ZnO-NaCMC nanocomposites. [ABSTRACT FROM AUTHOR]

Toxic dyes in water bodies and bacterial pathogens pose serious global challenges to human health and the environment. Zinc oxide nanoparticles (ZnO NPs) demonstrate remarkable photocatalytic and antibacterial potency against reactive dyes and bacterial strains. In this work, PVP-ZnO NPs have been prepared via the co-precipitation method using polyvinylpyrrolidone (PVP) as a surfactant. The NPs' microstructure and morphology were studied using X-ray diffraction (XRD), having a size of 22.13 nm. High-resolution transmission electron microscope (HR-TEM) and field emission scanning electron microscopy (FESEM) analysis showed spherical-shaped PVP-ZnO NPs with sizer ranging from 20 to 30 nm. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed the hybrid nature of the NPs, and UV–Vis spectroscopy showed an absorption peak at 367 nm. The PVP-ZnO NPs exhibited high photocatalytic activity, achieving 88% and nearly 95% degradation of reactive red-141 azo dye with 10 mg and 20 mg catalyst dosages, respectively. The antibacterial properties of the NPs were demonstrated against Escherichia coli and Bacillus subtilis, with inhibition zones of 24 mm and 20 mm, respectively. These findings suggest that PVP-ZnO NPs can be effectively used for water treatment, targeting both dye and pathogenic contaminants. [ABSTRACT FROM AUTHOR]

Advanced and eco-friendly construction materials are being developed to reduce pollution and improve wastewater treatment efficiency. One such material is a photocatalytic nanocomposite that uses industrial wastes and natural substances to eliminate pollution. A recent study explored using an inorganic polymer composite (FM) made from a mixture of 70% fly ash and 30% metakaolin, with sodium hydroxide and sodium silicate as an alkali activator. The study evaluated the mechanical and hydration characteristics of the FM composite after 28 days in 100% humidity at room temperature. The study also examined the effect of adding 2.5 wt.% of Nano-TiO2 to FM composite and how it affects its properties. Results indicate that adding Nano-TiO2 to FM composite enhances its mechanical, antibacterial, and photocatalytic capabilities. Specifically, FM-TiO2 composite showed 90% removal of reactive blue 19 dye effluent in sunlight after 90 min, making it an excellent choice for sustainable wastewater treatment. This study presents a cost-effective, eco-friendly solution to wastewater treatment, with added antimicrobial properties from Nano-TiO2. [ABSTRACT FROM AUTHOR]