Textile Dyeing Industry Research Articles

Adsorption of Rhodamine B on Spherical Activated Carbon synthesized from Waste Bagasse Liquid using Hydrothermal Process

The dyes of the textile dyeing industry wastewater are harmful to humans and the environment. They should be treated before discharging into the environment. The adsorption using the spherical activated carbon can be effective to reduce the dyes. The spherical activated carbon of 3-7 µm in diameter was successfully prepared from the waste bagasse liquid using the hydrothermal method. The activation of this carbon was carried out using the KOH solution. The optimum pH and contact time were achieved in 2 and 200 min, respectively. Adsorption kinetic for RhB on activated spherical carbon follows the second-order kinetics and its adsorption mechanism follows the Langmuir isotherm. The maximum adsorption capacity of spherical activated carbon to Rhodamine B was achieved in 64.52 mg/g.

More about Persulfate-Assisted Ferrilanthanide-Mediated Photocatalysis of Textile Industry Dye Reactive Black 5: Surface Properties and Structural Assessment

Color and organic matter removal from dyehouse effluent remains a challenging issue for the environmentalist and textile dyer. Until now, various treatment processes have been proposed with limited success. In this study, the textile dye and model industrial pollutant Reactive Black 5 (RB5; 20 mg/L) could be rapidly degraded by persulfate (PS)-enhanced photocatalytic treatment using a novel, home-made lanthanum iron oxide (LF; 0.5 g/L). LF-mediated heterogeneous photocatalysis was effective when the solution pH was kept below 4. The photocatalytic degradation of RB5 solution was enhanced in the presence of 0.6 and 1.2 mM PS. The dissolved organic carbon (DOC) content of the aqueous, hydrolyzed RB5 solution (initial DOC = 5.15 mg/L) was effectively reduced by LF/UV-A (LF = 0.5 g/L; 52–54% DOC removal after 150–180 min) and LF/PS/UV-A (LF = 0.5 g/L; 60–66% DOC removal after 120 min) treatments. LF photocatalyst could be reused in four consecutive cycles for complete color and partial DOC removals without significant deterioration of the treatment performance with the LF/PS/UV-A/pH 3 process. Instrumental analyses of LF’s surface morphology/chemical composition and structural features via EDAX/SEM/Raman/FTIR/UV-vis/fluorescence spectroscopy indicated that LF remained practically intact throughout photocatalytic treatment, though slight changes/decreases in particle size/partial surface deformation and agglomeration coverage were observed, particularly during LF/PS/UV-A treatment. The presence of RB5 and its degradation products on the LF surface revealed that surface adsorption played a major role in LF-mediated photocatalysis. The Fe-content did not deviate appreciably from its original value after photocatalytic treatment.

Isolation and identification of naturally occurring textile effluent-degrading bacteria and evaluation of their ability to inhibit potentially toxic elements

Untreated textile dye-contaminated wastewater contains potentially toxic elements (PTEs) and causes pollution when discharged. Herein, we attempted to isolate and identify naturally occurring effluent-degrading bacteria and investigate their resistance potentials against various PTEs. Wastewater samples were collected from the biological effluent treatment plant of a textile dyeing industry located at the Chattogram Export Processing Zone, Bangladesh. The effluent samples contained Pb and Cr, with 27 times higher Cr content than the regulatory limit. A total of 14 bacterial isolates were isolated from the effluent based on differences in their cultural properties. Based on morphological and biochemical features, isolates were identified as Staphylococcus xylosus, Bacillus korlensis, Pseudomonas fluorescens, Pseudomonas cichorii, Brevundimonus diminuta, and Enterococcus columbae. Isolates were primarily screened for their ability to reduce the content of PTEs, such as Cr, Pb, Mn, Cu, and Cd. Pre-incubation of effluents and isolates revealed that most bacteria reduced the PTEs in the effluent. Of the 14 isolates, six exhibited potential in reducing most of the PTEs—Cd (94–99%). Further, Cr was decreased by 68 and 61% in the presence of S. xylosus and P. fluorescens, respectively, after 72 h of incubation in a medium containing 400 mg L−1 salt. The findings of this study can provide insights into the efficient biological remediation of PTEs in industrial wastewater.

Effect of Dispersant on Disperse Dyeing in Silicone Waterless Dyeing System

Traditional water-based dyeing of polyester textiles usually generates burdensome processes and a great deal of wastewater, which can no longer meet the green and sustainable developments in the textile dyeing industry. In the silicone waterless dyeing system, polyester textiles can be dyed with disperse dye without water. However, the dyeing performance of polyester textiles is influenced by the dispersant. In this study, the relationship between the properties of dispersants and disperse dyeing performance was studied. When the amount of dispersant NNO (2-Naphthalenesulfonic acid) was 1.2%, the exhaustion of disperse red 177 and the final K/S value of the dyed fabric improved to 94.18% and 14.73, respectively. However, the exhaustion of disperse red 177 was reduced from 90.73% to 82.61%, and the final K/S value of the dyed fabric was decreased from 14.77 to 14.01 when the dosage of MF (Naphthalenesulfonic acid) was 1.2%. Compared with different dyeing systems, the final uptake of disperse red 177 was 93.81% and 94.18% in traditional water-based and silicone waterless dyeing systems and the K/S value of the dyed fabric was almost the same. The washing and rubbing fastness (wet and dry) of the dyed fabric were found to be at a level of 4 or 4-5, and the light fastness of the dyed fabric was 3-4. If only the dispersant was added in the silicone waterless dyeing system, there was no leveling problems on dyed samples. Moreover, the maximum absorption wavelength of disperse red 177 was not changed after adding the dispersant. With an increasing amount of dispersant NNO, the solubility of the dye in the silicone solvent decreased, but it increased with an increasing amount of dispersant MF. In the relationship between dye exhaustion and dye solubility in a silicone waterless dyeing system, the exhaustion of dye was linearly and inversely proportional to the dye solubility. A dispersant with better hydrophilicity can decrease the solubility of the dye in dyeing media, and the dyeing performance of dye is better. Compared with previous studies, the exhaustion of dye was consistent with the ClogP value (hydrophobic constant) of the dyeing accelerant. Therefore, a dispersant with high hydrophilicity can reduce the solubility of dye and improve the exhaustion of disperse dye in a silicone waterless dyeing system. Moreover, the color fastness of the dyed fabric did not change before and after adding the dispersant.

Phytotoxicity Assessment and Nanotechnological Remediation of Textile Industrial Dyes on Vegetation

In current scenario, one of the most significant sources of pollution is textile dye and increasing day by day. Many issues confront global agriculture, including the sustainable use and protection of natural resources, climate change, urbanisation, and pollution caused by agrochemicals (e.g., fertilisers and pesticides). These businesses release a wide range of chemicals, dyes, acids and alkalis, as well as other toxic compounds such as heavy metals, all of which are known to be poisonous. The physico-chemical parameters of dye manufacturing effluents, as well as their impact on seed germination and plant growth, were studied. Nanotechnology is also being studied as a potential solution to the worldwide food crisis. The use of plants to remove toxins from the soil, such as heavy metals, trace elements, organic chemicals, and radioactive substances. It also explains how nanoparticles are becoming a popular method of desalination and it also faces the environmental challenges for the protection of plants.

Characteristics of cotton fabric dyed with Euphorbia extract at different concentrations of cellulosic nanoparticles (CNP)

As the perception of the consumer's environment and the toxicity of synthetic dyes that is harmful to humans, interest in natural dyes is also increasing in the textile dyeing industry. This study performed an alternative to metal mordants and used cellulose nanoparticles (CNP) as a natural mortant for dyeing cotton fabrics with natural dyes extracted from Euphorbia. The characteristics with and without CNP mordant were investigated in the experiment. The effects of natural cellulosic mordants were analyzed through color, fastness, color, fastness, air permeability, antibacterial rate, UV protection, and total hand value (THV). As a result, the light fastness has been shown to significantly increase, but the improvements in terms of the wash, perspiration, and rubbing fastness were negligible. In addition, when CNP was added to cotton dyeing, there was no difference change in air permeability, but THV was significantly improved to 5 or more, and the UV protection and bacteria reduction rate were excellent. These results are attributed to the groundwork for studies on other types of natural dyes in the future and, by establishing the benefits of CNP, this study significantly contributes to the improvement of the end-products of dyeing.

Unraveling the corrosion kinetics of gallium-aluminum for efficient hydrogen production from water at zero CO2 emission

Hydrogen (H2) generation via metal hydrolysis is a promising eco-friendly technique that has been widely accepted by the industrial sector. This work mainly focuses on stable H2 production through a simple surface-etching process by hydrofluoric acid (HF) to expel the passive aluminum oxide (Al2O3) layer. The HF-treated aluminum (Al) metal is allowed to react with liquid gallium (Ga) adopting Al–Ga hydrolysis in three different electrolytic solutions of hydrochloric acid (HCl), sodium hydroxide (NaOH), and neutral sodium chloride (NaCl) solutions (named Ga-Al-water reaction). Significantly, the high H2 productivity of 95.9% achieved in 0.4 M NaCl solution at various temperatures (35–65 °C), further maintained the long-term stability of 92.3% for about 25 h at 35 °C. Density functional theory (DFT) calculations confirm the spontaneity of the initial Al oxidation by the Ga liquid metal, leading to spontaneous water-splitting reactions. Furthermore, the Ga catalyst was recovered even after five reusability cycles without productivity decay. This method yields aluminum hydroxide (Al(OH)3) as reaction byproducts which could enable resource circulation in pharmaceutical, textile dyeing, and various chemical industries. This study demonstrates the feasibility of the new Ga-Al-water system with an enhanced Ga–Al contact for large-scale H2 production from seawater and portable fuel cell devices.

Removal of Reactive Blue 19 dye from synthetic wastewater using UV/H2O2 and UV/Cl advanced oxidation processes

AbstractThe textile and dyeing industries are among the largest water‐consuming and polluting industries in the world. The most important feature of the textile dyeing industry wastewater is its color, due to the use of colored materials. Most of these dye compounds are resistant to conventional purification methods and their biodegradation is very low through secondary purification processes, resulting in incomplete removal. Therefore, selecting the optimal method to remove these color compounds is essential. In this study, we studied the removal of an organic dye contaminant (Reactive Blue dye 19 [RB19]) using advanced oxidation processes (AOPs). For this purpose, ultraviolet (UV) mercury lamps with a wavelength of 254 nm and a voltage of W16 inside a reactor were used as an energy source. The experiments were performed in a collimated beam reactor inside a dark chamber. Two oxidizers, sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2), were used to remove RB19 from the artificial sewage stream. Removal of RB19 with a concentration of 20 mg/L with variable pH (5, 7, and 9), oxidant concentrations (5, 10, and 20 mg/L), and time (5, 10, 15, and 30 min) were investigated during the processes of photolysis, chemical oxidation (by H2O2 and NaOCl), and UV/NaOCl and UV/H2O2 AOPs. The photolysis process did not remove the RB19. The highest removal efficiencies of RB19 by chemical oxidation processes with NaOCl and H2O2, UV/NaOCl, and UV/H2O2 at optimal conditions (pH = 5, [oxidant] = 20 mg/L, RB19 = 20 mg/L, and radiation intensity of 1005 mJ/cm2) were 64.49%, 0.88%, 99.7%, and 13.31%, respectively. These results indicate that the hydroxyl radical was produced, under optimum conditions, more in the acidic medium; thus, the RB19 removal efficiency was higher in the acidic medium. The combination of UV rays with oxidants resulted in the production of more hydroxyl radicals and increased removal efficiency.

Analysis of physicochemical characteristics of textile and printing industrial effluents and their influence on vegetation near industrial drain areas in Sanganer, Jaipur (Rajasthan)

A significant threat to the ecosystem and the variety of life forms is posed by the massive amount of garbage that has been produced as a result of rapid industrialisation. Up to 20% of industrial water pollution is contributed by the textile industry, one of the largest industries in the world. Rajasthan occupies a unique position in the textile dyeing and printing industry as a significant economic sector. The textile sector is also regarded as one of the major environmental risks. Many dyes, chemicals, and other substances are used by the textile industry to give fabrics the properties they need. Because textile industries use a lot of water and chemicals, their dyeing units produce a huge amount of effluents that are harmful. The volume of effluents produced by these operations is substantial. They not only have detrimental impacts on the soil and water quality, but they also endanger the health of plants and animals. In this investigation, the physicochemical parameters of industrial effluents from four different sites at the Sanganer textile industrial area were studied to access the quality of effluents and results were compared to textile effluent standards prescribed by the Rajasthan State Pollution Control Board. The samples were alkaline besides having high chemical oxygen demand. Two different vegetation areas near Sanganer industrial drainage were also identified and studied to analyse the effects of effluents on the growth of plants. It has been noted from the study that the textile wastewaters exhibit extreme variations from the CPCB guidelines in terms of pH, TDS, and EC. The outcomes also show that the effluents have a pollutant load that is significantly larger than the raw water utilised.

Characterization of Textile Dyeing Effluent and Removal Efficiency Assessment of Al2(SO4)3 Coagulant

The textile dyeing industry discharges a variety of effluents into nearby surface water bodies, which pose a threat to the environment. The study aimed to characterize the effluents and evaluate the coagulant efficiency of Al2(SO4)3 for the treatment of textile effluent. This investigation deals with studying the parameters affecting coagulation-flocculation (C-F) behavior, such as coagulant dose, reaction time, pH, and temperature, using a jar test apparatus. The analyzed parameters before and after treatment are pH, dissolved oxygen (DO), electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), biological oxygen demand (BOD), and some anions. The analysis results showed that the textile dyeing effluent was highly alkaline, and parameters like EC, TSS, TDS, COD, BOD, and some anions were found to be higher than the DoE-BD standard guidelines for effluent discharge, indicating that the effluents are loaded with high amounts of organic and inorganic pollutants. The study optimized the process parameters of the coagulation The study optimized the process parameters of the coagulation, which illustrated that the Al2(SO4)3 coagulant potentially reduced pH, EC, TDS, TSS, BOD, and COD from the effluents. The study observed that the highest removal of COD and BOD was 66% and 74% for the samples Ef2 and Ef3, respectively. The highest TSS removal rate was around 90% for Ef3, and almost 80% TDS removal was achieved for all effluents. The results indicated that Al2(SO4)3 showed a better coagulant efficiency for reducing the concentration of several physicochemical parameters in wastewater, and the treated effluent satisfied the DoE-BD standards for discharging wastewater into the public sewage network. Hence, Al2(SO4)3 would be a potential coagulant for treating the textile effluents that help to build a sustainable environment.

Assessment of health status among workers of textile dyeing industry in the middle region of the Nile Delta Egypt

Assessment of health status among workers of textile dyeing industry in the middle region of the Nile Delta Egypt

Performance evaluation study of effluent treatment plant of polyester textile dyeing industry: a case study of SIDCUL, Haridwar, Uttarakhand, India

Performance evaluation study of effluent treatment plant of polyester textile dyeing industry: a case study of SIDCUL, Haridwar, Uttarakhand, India

Treatment of Textile Dyeing Effluent Using Agriculture Waste Based Adsorbents - A Review

Objective: Removal of colour from the textile dyeing effluent is a major problem due to high tinctorial value, complex structure of the dyes, toxicity and presence of metals in some dyes. The colouring matter has to be removed from the effluent before its discharge as it constitutes the major fraction of pollution. The spent dyes in the textile effluent have to be removed before disposal as they constitutes major fraction of pollution. Review of waste based adsorption of the spent dyes, performance, economics involved and disposal options for the spent adsorbents are the objectives of the present work.
 Methods: Various techniques are used for the removal of colour including adsorption. Although the activated carbon is an ideal adsorbent, it is expensive for effluent treatment due to its high production and regeneration costs. High cost of activated carbon has led to the search for alternate non-conventional adsorbents. Attempts have been made by researchers to use the non-conventional, low-cost and naturally occurring waste materials as adsorbents. The findings are based on literature survey and authors’ experience.
 Findings: This review seeks to give an overview of the agriculture waste based adsorbents together with physical and chemical processing needs, adsorption parameters including mechanisms and the adsorption potential of various adsorbent-adsorbate systems for removal of different dyes from the effluents. Comparative studies conducted with synthetic effluents as well real textile dyeing effluent are also included. The cost involved in the dyeing effluent treatment is always a concern for the textile dyeing industries. The cost issue can be addressed using the waste based adsorbents for which an economics have been presented.
 Conclusion: The gaps between practices and the present research works have been identified and highlighted along with further research needs for treatment of the dyeing effluents. The waste based adsorbents are mainly agricultural residues and combustible. The spent adsorbents can be reused as fuel in the boiler furnace that can offset the expenses on fuel to some extent.

Fate of Sulfate in Municipal Wastewater Treatment Plants and Its Effect on Sludge Recycling as a Fuel Source

Wastewater sludge is used as an alternative fuel due to its high organic content and calorific value. However, influent characteristics and operational practices of wastewater treatment plants (WWTPs) can increase the sulfur content of sludge, devaluing it as a fuel. Thus, we investigated the biochemical mechanisms that elevate the sulfur content of sludge in a full-scale industrial WWTP receiving wastewater of the textile dyeing industry and a domestic WWTP by monitoring the sulfate, sulfur, and iron contents and the biochemical transformation of sulfate to sulfur in the wastewater and sludge treatment streams. A batch sulfate reduction rate test and microbial 16S rRNA and dsrB gene sequencing analyses were applied to assess the potential and activity of sulfate-reducing bacteria and their effect on sulfur deposition. This study indicated that the primary clarifier and anaerobic digester prominently reduced sulfate concentration through biochemical sulfate reduction and iron–sulfur complexation under anaerobic conditions, from 1247 mg/L in the influent to 6.2~59.8 mg/L in the industrial WWTP and from 46.7 mg/L to 0~0.8 mg/L in the domestic WWTPs. The anaerobic sludge, adapted in the high sulfate concentration of the industrial WWTP, exhibited a two times higher specific sulfate reduction rate (0.13 mg SO42−/gVSS/h) and sulfur content (3.14% DS) than the domestic WWTP sludge. Gene sequencing analysis of the population structure of common microbes and sulfate-reducing bacteria indicated the diversity of microorganisms involved in biochemical sulfate reduction in the sulfur cycle, supporting the data revealed by chemical analysis and batch tests.

Taguchi L16 (44) orthogonal array-based study and thermodynamics analysis for electro-Fenton process treatment of textile industrial dye

Abstract Reactive orange 16 (RO16) is the most widely used azo dye in Textile industry. Complex aromatic structures and resistivity to biological decay caused the dye pollutants incompletely treated by the conventional oxidative methods. The current study presents the electro-Fenton-based advanced oxidation treatment of RO16 dye and the process optimization by Taguchi-based design of experiment (DOE). Using a 500 mL volume lab-scale experimental setup, the process was first studied for the principal operational parameters (initial dye concentration (q); [H2O2]/[Fe+2] (R); current density (ρ); and temperature (T)) effect on decolourization (D R ) and COD removal (C R ). Then, by means of the L16 (44) orthogonal array (OA) formation, standard mean and signal-to-noise (S/N) ratio, the process was optimized for the response variables. The result showed the optimized result at q = 100 mg/L, R = 100, ρ = 8 mA/cm2, and T = 32 °C; with D R and C R as 90.023 and 84.344%, respectively. It was found that the current density affects the process most, followed by [H2O2]/[Fe+2] ratio, initial dye concentration, and temperature i.e., ρ > R > q > T. Also, with the analysis of variance (ANOVA), model equations for D R and C R were developed and its accuracy was verified for experimental results. At optimized conditions, the first order removal rate constants (k a ) were found from batch results. Additionally, the thermodynamic constants (ΔH e , ΔS e , and ΔG b ) were also calculated for the nature of heat-energy involved and temperature effect study on dye degradation. The results showed that the process was thermodynamically feasible, endothermic, and non-spontaneous with a lower energy barrier (E A = 46.7 kJ mol−1).

Impact of textile dyes on health and ecosystem: a review of structure, causes, and potential solutions.

The rapid growth of population and industrialization have intensified the problem of water pollution globally. To meet the challenge of industrialization, the use of synthetic dyes in the textile industry, dyeing and printing industry, tannery and paint industry, paper and pulp industry, cosmetic and food industry, dye manufacturing industry, and pharmaceutical industry has increased exponentially. Among these industries, the textile industry is prominent for the water pollution due to the hefty consumption of water and discharge of coloring materials in the effluent. The discharge of this effluent into the aquatic reservoir affects its biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), and pH. The release of the effluents without any remedial treatment will generate a gigantic peril to the aquatic ecosystem and human health. The ecological-friendly treatment of the dye-containing wastewater to minimize the detrimental effect on human health and the environment is the need of the hour. The purpose of this review is to evaluate the catastrophic effects of textile dyes on human health and the environment. This review provides a comprehensive insight into the dyes and chemicals used in the textile industry, focusing on the typical treatment processes for their removal from industrial wastewaters, including chemical, biological, physical, and hybrid techniques.

One-year spatiotemporal variations of air pollutants in a major chemical-industry park in the Yangtze River Delta, China by 30 miniature air quality monitoring stations

Fine chemical industrial park (FCIP) is a major source of atmospheric pollutants in China. A long-term high spatial resolution monitoring campaign on air pollutants had been firstly conducted in a major FCIP in Yangtze River Delta (YRD) from December 2019 to November 2020. The grid-based monitoring platform consisting of 30 miniature air quality monitoring stations (AQMSs) provided comprehensive coverage of a FCIP, and long-term monitoring studies solved the problem of lack of clarity about pollution sources in industrial parks. Overall, NO2 pollution was particularly high in the pharmaceutical industry, while TVOCs and O3 pollution were most serious in the textile dyeing industry, with PM pollution much higher in the metal smelting industry than in other industries, and in the leather industry, O3 pollution was relatively severe. The spatial and temporal variations of air pollutants showed that higher PM, CO and NO2 concentrations were revealed in winter while lower in summer due to better meteorological diffusion conditions. TVOCs concentrations were higher with an average of 1954 ppb in summer possibly due to their increased volatilization from their sources at higher ambient temperatures. O3 concentrations were at their peaks in spring (88.8 μg m−3) and early fall (78.5 μg m−3). The daily trends of O3 precursors (TVOCs and NO2) were clearly negatively correlated with O3, and they showed bimodal peaks due to anthropogenic activities, plant emissions, lowering of the mixed boundary layer, etc. The O3 formed in FCIP was judged to be NO2-limited during the monitoring period based on the ratios of NO2 to TVOCs. Therefore, the effective strategy to reduce O3 formation in FCIP is to decrease the ambient NO2 concentration. Based on Pearson correlation coefficients, it appeared that WS promoted O3 formation through long-term transport and that high air temperatures also contributed to O3 formation in the environment. It was also stated in the study that the closer the residential area is to the industrial sources, the more significant the correlation. Thus, the results of this study will also be helpful for policymakers to design pollutant control strategies for different industries to mitigate the impact of pollutants on human health.

Exfoliated gC3N4 supported CdS nanorods as a S-scheme heterojunction photocatalyst for the degradation of various textile dyes

• CdS nanorods anchored on exfoliated gC 3 N 4 . • CdS-gC 3 N 4 catalyst degraded various commonly used dyes in textile industries. • CdS-gC 3 N 4 acts as a S-scheme catalyst to degrade the dyes. • The catalyst manifested excellent catalytic efficiency and reusability. The quest to develop efficient photocatalysts in order to maintain a harmonious ecosystem by reducing water pollution from wastewater discharged from various industries is still in progress. Herein, we report a photocatalyst synthesized from exfoliated graphitic carbon nitride (gC 3 N 4 (ex)) and cadmium sulfide (CdS) which manifested excellent catalytic activity towards the degradation of various textile dyes in the presence of H 2 O 2 (50CdS-50gC 3 N 4 (ex)). Under optimum reaction conditions, ∼100 % degradation of some textile dyes such as Turq CL 5B, Red CL 5B, Yell CL 2R, Navy CLR, CB Sol Navy R, and Lanasol Black CE were observed in 10, 15, 30, 25, 30, and 15 min, respectively, when 50CdS-50gC 3 N 4 (ex) was used as the photocatalyst. This excellent photocatalytic efficiency of 50CdS-50gC 3 N 4 (ex) ascends from the establishment of synergy between nanorod-shaped CdS and exfoliated tubular-shaped gC 3 N 4 due to their intimate concomitance in the nanocomposite. Moreover, the catalyst showed ∼93 % catalytic efficiency as well as no change in the crystal structure or morphology after five catalytic cycles. Hence, this work puts forward a highly efficient environment-friendly, and reusable catalyst (50CdS-50gC 3 N 4 (ex)) which demonstrated its excellent potentiality to be utilized in the treatment of polluted effluents from textile industries under solar or blue LED irradiation.

Reproducibility of Shade During Dyeing of Cotton/Polyester Fabric by Varying the Process Condition

ABSTRACT In every textile dyeing industry shade matching is the most frequent process and achieving the same shade every time is still a very challenging process. The fabric was dyed with the same recipe after some duration for the same shade but it showed more variation in the shade than the previously dyed fabric. This problem of reproducibility was tried to be minimized by working on some process parameters and the results found were appreciable. To overcome the shade variation numerous trials have been conducted with the dyeing process and recipes. The reproducibility of shades benefitted dyeing to some extent in saving chemicals reducing time minimizing energy utilization with reducing cost generating more accurate results and minimization of shade variations so a program must be developed that can dye the fabric every time without any variation. Temperature and time are the two main factors to be considered along with the selection of chemicals and auxiliaries during dyeing to get minimum shade variation. This paper describes the critical process parameters and their control measures to achieve shade reproducibility in the dyeing of cotton/polyester blend fabric.

Dispersive solid-phase extraction for determination of fast green and erythrosine dyes in environmental water samples using Zein bio-nanoparticles

ABSTRACT Colour additives are commonly used in the food industry to improve product appearance and nutritional characteristics. However, effluent containing reactive dyes from food and textile dyeing industries is a substantial cause of pollution in the environment. Simple and ecofriendly trace analysis of two synthetic food azo dyes including fast green (FG) and erythrosine (ER) dyes from environmental water samples was developed by combining dispersive μ-solid-phase extraction with UV-Vis spectrophotometric detection. Zein biopolymeric nanoparticles (ZNPs) were used as a green sorbent for preconcentration of trace amounts of the mentioned food dyes. Based on the anti-solvent method, the ethanolic Zein solution (20 mg) was injected rapidly into the sample, and the ZNPs were produced. After centrifugation, the adsorbed dye was separated, and samples were analysed using a spectrophotometric technique. The impact of various extraction parameters, such as extraction time, adsorbent amount, surfactant type and concentration, ionic strength, pH of sample solution, and desorption conditions, was examined. Under optimised conditions, the linearity ranges were 0.005–1.2 and 0.01–2 µg mL−1 with correlation coefficient (r2) of 0.9970 and 0.9972 for FG and ER respectively. The method has good reproducibility, with relative standard deviations of less than 4.2% (n = 5) and detection limits of 2.5 and 6 ng mL−1 for both dyes respectively. The current approach was used to analyse three environmental water samples (river, canal, and well water), and the dyes recoveries were 94.0–102.6% and 95.7–101.7% for FG and ER respectively. The findings revealed that the proposed approach was convenient, fast, and effective.