Dyeing Units Research Articles

Early prediction of fabric quality using machine learning to reduce rework in manufacturing processes

The increasing competition and rapid technological advancements in today's business world have raised customer expectations. People now expect quick delivery, low prices, and high-quality products. As a result, companies must adapt to this competitive environment to survive. Rework, which is a significant cost in production, increases expenses, reduces production efficiency, and can lead to customer attrition. Research shows various efforts across different sectors to reduce rework, although there is still a gap in the textile sector's fabric dyeing units. Common problems in these units include non-retentive colors, customer dissatisfaction with shades, and repeated dyeing due to environmental factors or dye vat issues. This study uses logistic regression and artificial neural networks models from machine learning to predict which fabrics will need rework, using data from a textile company in Bursa. The analysis indicates that artificial neural networks models perform better.

Advancement in extraction and characterization techniques of natural dyes from dye yielding plants sources: a review

Purpose Everyone is extremely concerned about environmental protection and health safety due to the rise in living standards. Plant-derived natural dyes have garnered much industrial attention in food, pharmaceutical, textile, cosmetics, etc. owing to their health and environmental benefits. The present study aims to focus on the elimination of the use of synthetic dyes and provides brief information about natural dyes, their sources, extraction procedures with characterization and various advantages and disadvantages. Design/methodology/approach In producing natural colors, extraction and purification are essential steps. Various conventional methods used till date have a low yield, as these consume a lot of solvent volume, time, labor and energy or may destroy the coloring behavior of the actual molecules. The establishment of proper characterization and certification protocols for natural dyes would improve the yielding of natural dyes and benefit both producers and users. Findings However, scientists have found modern extraction methods to obtain maximum color yield. They are also modifying the fabric surface to appraise its uptake behavior of color. Various extraction techniques such as solvent, aqueous, enzymatic and fermentation and extraction with microwave or ultrasonic energy, supercritical fluid extraction and alkaline or acid extraction are currently available for these natural dyes and are summarized in the present review article. Originality/value If natural dye availability can be increased by the different extraction measures and the cost of purified dyes can be brought down with a proper certification mechanism, there is a wide scope for the adoption of these dyes by small-scale dyeing units.

Bacterial bioremediation of textile effluent dyes contaminated sites

Water and soil pollution caused by industrial effluent has become an alarming threat to environmental safety. This is mainly because of the direct discharge of textile effluents into the water bodies, without any pre-treatments. To resolve this, microbial bioremediation is used for the effective removal of the dyes and toxic compounds present in textile effluents. The textile dye-degrading isolates (3A, 4A, 5B and 6B) were isolated from the soil samples collected at the dye contaminated sites. Synthetic textile dyes, Brill Red 3BN and Blue SE2R obtained from the textile dyeing units were used as positive control for this study. The genus of the dye degrading isolates was identified by morphological and biochemical characterization. Based on the results, the isolates were belonged to the genus Pseudomonas. All four strains are producing both pyomelanin (brown) and pyoverdine (green) pigments during their growth. Maximum tolerance concentration (MTC) test, growth kinetics, decolorization and degradation studies were performed to analyze the dye degrading potential of isolates. Strain 3A and 6B showed more than 80% of decolorization up to 2500 ppm dye mix within 5 days of incubation. Isolates used textile dye as their sole carbon source for their growth and development. The biodegraded dye was analysed by GC-MS to measure the dye degrading ability of isolates.

Detoxification and decolorization of complex textile effluent in an enzyme membrane reactor: batch and continuous studies.

There is an urgent need to look for bio-based technologies to address the pollution related to textile dyes in waterbodies. The aim of this study was to evaluate an engineered laccase variant, LCC1-62 of Cyathus bulleri, expressed in recombinant Pichia pastoris, for the decolorization and detoxification of real textile effluent. The partially purified laccase effectively (~60-100%) decolorized combined effluent from different dyeing units at a laccase concentration of 500 U/L at a 50-mL level. Decolorization and detoxification of the combined effluents, from a local textile mill, were evaluated at 0.3 L volumetric level in a ray-flow membrane reactor in batch and continuous modes of operation. In batch studies, maximum decolorization of 97% and detoxification of 96% occurred at a hydraulic retention time (HRT) of 6 h without any additional laccase requirement. In continuous studies, the reactor was operated at an HRT of 6 h with a lower enzyme dosage (~120 U/L of the effluent). Decolorization was accompanied by a loss in laccase activity which was restored to ~120 U/L by the addition of laccase in two regimes. The addition of laccase, when the residual laccase activity decreased to 40% (~50 U/L), resulted in high decolorization (~5 ppm residual dye concentration) and low variance (σ2) of 2.77, while laccase addition, when the residual dye concentration decreased to ~8% (~10 U/L), resulted in an average dye concentration of 13 ppm with a high variance of 62.08. The first regime was implemented, and the continuous reactor was operated for over 80 h at an HRT of 3 and 6 h, with the latter resulting in ~95% decolorization and 96% reduction in the mutagenicity of the effluent. Less than 10% membrane fouling was observed over long operations of the reactor. The findings strongly suggest the feasibility of using LCC1-62 in an enzyme membrane reactor for large-scale treatment of textile effluents.

Dermatological Symptoms among Polyester Dyeing and Printing Workers in Mumbai.

Textile is one of the important sectors in the Indian economy. The use of synthetic chemicals is maximum during the wet processing technique, which consists of dyeing, printing and finishing. This study was conducted to find out the prevalence of occupational dermatological symptoms among the workers employed in the dyeing and printing unit of the textile industry. A cross-sectional study, with a sample of 242 workers, was conducted in three different dyeing and printing factories. The workers were interviewed using a semi-structured questionnaire adapted from the Nordic Occupational Skin Questionnaire. The prevalence of dermatological symptoms on the hands was found to be 51.7%. The various pattern of lesions included redness in 0.4% to itching in 26% of dyeing and printing workers. Those working for >5 years had 2.21 times higher risk as compared to those working for ≤5 years Odds Ratio (OR): 2.21; 95% Confidence Interval (CI): 1.19-4.11). Similarly, those working in the dyeing section were at 2.94 times higher risk as compared to those working in the printing section (OR: 2.94; 95% CI: 1.58-5.47). The workers working in the printing and dyeing industry were at risk of developing skin lesions, which can partly be attributed to reactive chemicals used and partly to poor handling practices of the workers.

PENETRATION AND REPELLENCY OF CHEMICAL PROTECTIVE COVERALLS

Present study was to evaluate chemical penetration and repellency of locallymanufactured protective coveralls used by the workers of fertilizer manufacturing units. The researchwas based on laboratory work performed and completed at Dyeing and Finishing Unit, Nishat MillsLimited. The samples were evaluated for their chemical resistance at various laundering intervals byISO 6530:2005 test methods. Chemical penetration and repellency of three different fabrics were testedagainst four different chemicals. The results showed that all the samples were unable to resist chemicalattack and their condition, became even worse with repeated washing cycles. At 20th washing cycle,98.5% chemicals penetrated synthetic fiber (polyester) whereas chemical penetration for blended fiberwas recorded at 98.9% and for natural fibers was recorded at 99.1%. Similarly chemical repellency fornatural and synthetic fiber was recorded at 0% whereas for blended it was recorded 1at 0.4%.According to the test results, out of all the three samples, synthetic fiber performed better againstchemical attacks.

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.

Simulation of an industrial scale scCO2 beam dyeing process

An industrial dyeing process in supercritical carbon dioxide has been modelled with computational fluid dynamics using Ansys Fluent software. In order to investigate the distribution of the dye carrier fluid, the flow resistance of the fabric has been accurately characterised. For this purpose, in the first part of the work a plain-woven fabric geometry was created in the open software Tex-Gen and modelled in Ansys Fluent to predict the permeation of fluid through the pores of the fabric material and to estimate the relationship between local fluid velocity and pressure drop. The second part of the study focused on evaluating the influence of beam structure, inlet flow rate, fabric height on the fluid flow through the fabric, which must be uniform to achieve a homogeneous level of dyeing. From the simulations the main obstacle to achieving a uniform flow velocity in the fabric is the pressure rise that occurs in the beam and creates a slight difference in permeation velocity between the two axial ends of the fabric; other disturbances, such as the effect of the perforated structure of the beam, are usually minor. Due to the low viscosity of supercritical carbon dioxide, inertial losses predominate over viscous losses in the porous medium. This means that approaches based only on the permeability of the fabric and the application of Darcy's law are inadequate to correctly predict the response of a dyeing unit when using carbon dioxide.

Evaluation of corrosion and scaling tendency of polyester textile dyeing effluent, Haridwar, Uttarakhand, India.

Textile dyeing industries are regarded as one of the most polluting by virtue of the chemicals used and wastewater released. A great deal of chemicals, fasteners, dispersing agents is employed in the stages of dyeing and finishing. The aim of the study was to evaluate scaling and corrosion tendency of polyester textile dyeing effluent using Langelier saturation index (LSI), Ryznar stability index (RSI), and aggressiveness index (AI). The estimation of water stability indices helps in assessing the scaling and corrosive nature of wastewater which in turn facilitates evaluating the condition of the pipelines and valves. Wastewater released from textile dyeing units contains high levels of color (892 ± 20Pt-Co), chemical oxygen demand (2461 ± 48.45mg/L), electrical conductivity (2906 ± 5.77 μS/cm), and sulfate (6620 ± 7.22mg/L). The LSI ranged from 2.12 to 3.45, RSI varied from 2.84 to 5.62, and AI varied from 13.67 to 14.99. It was found from the results that the polyester textile dyeing effluent was scaling and non-aggressive. Also, the pipes containing this effluent have to undergo regular maintenance so that they are not blocked by scales which can render financial losses to the industry.

Replacing chloride anions in dyeing enables cheaper effluent concentration and recycling

Reverse osmosis followed by distillation is commonly used to recycle fresh water and concentrated brine in the textile dyeing industry to achieve zero liquid discharge. The chemistry of industrial effluents is governed by the choice of chemicals used in various processing steps. This study experimentally demonstrates that replacing chloride with sulfate anions in the dyeing process baths can lead to significant energy savings in effluent treatment by enabling the use of NF membranes for brine concentration. The impact of electrolyte choice and concentration on fabric color is evaluated in a dyeing unit. While achieving similar fabric color, thermodynamic minimum energy consumption for sulfate brine concentration is around 50% lower as a result of its lower osmotic pressure. Practically, we show that while an RO membrane can concentrate the sulfate brine up to 60 g/kg at 60 bar applied pressure, nanofiltration membranes can concentrate the same to around 99 g/kg at the same pressure as a result of its higher permeability. Commercially acceptable color reproducibility was achieved for 3–5 cycles for different shades of dyeing when reusing NF brine in the dyebath. Ultrafiltration treatment of the concentrated brine reduces color deviation by 50–80% and is a promising method for brine polishing.

OPTIMIZATION OF REACTIVE DYEING PROCESS FOR CHITOSAN TREATED COTTON FABRIC

The colour of textiles plays an important role in the marketability of fabrics, due to its psychological and eye-catching effects on consumers. Synthetic dyes are widely used in the textiles industry due to their ability to reproduce different colours and shades, easy application method and huge production to fulfill the demands of ever-increasing population. Reactive dyes are most commonly used for cotton fabric, due to their brilliant colours and good washing fastness. However, the major problem with reactive dyes is that they consume huge amounts of alkali or salts as mordant for the fixation of dyes on cotton fabric. Most of the commercial dyeing units and textile export houses have started seeking possibilities to use safe synthetic dyes for dyeing different textiles for targeting the niche market. For that purpose, appropriate standardized scientific dyeing techniques and procedures need to be adopted. In the present study, the use of chitosan as mordant, instead of alkali or salt, was investigated for dyeing cotton fabric with reactive red dye, and the dyeing variables were optimized to attain the maximum colour strength value. The results of study showed that higher percent dye absorption (78.90%), colour strength (18.72) and good wash fastness rating (4/5) were achieved for the chitosan treated dyed fabric, compared to the alkali treated dyed sample (68.36% and 13.03, respectively).

Biochar from oil cakes: an efficient and economical adsorbent for the removal of acid dyes from wool dye house effluent

In the reported study, biochars were prepared from almond, coconut, and mustard oil cakes by chemical activation with phosphoric acid followed by low-temperature pyrolysis. The ball milling technique was employed to reduce the particle size of the biochars below 300 nm. The synthesized biochars were characterized by various analytical techniques like Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray diffraction spectroscopy, BET surface analysis, porosity measurement, methylene blue value and further employed for the removal of color from the acid dye effluent from the wool dyeing unit. The results showed that very small quantities (2.0 %) of biochars are sufficient to remove around 92% color from the dye effluent. The adsorption properties of the synthesized biochars were found to be greatly depending on the type of oil cake used. Among the three selected oil cakes, viz. mustard, coconut, and almond, the later was found to be performed well in terms of color removal. The batch adsorption and kinetic studies indicate the second order pathway of color removal for the synthesized biochars.

A novel approach on usage of waste sludge from textile dyeing units in paver block manufacturing

The viability of using textile sludge as a partial substitute for sand and cement in the construction of paving blocks is being investigated in this study. Along with the sludge, chemicals such as fly ash and lime are applied. The sludge was collected near the dyeing unit and put through a stabilization process to reduce the negative impact on paver blocks. For paver block casting, various trial mixes of M20 grade concrete were created. Compressive strength, split tensile strength, flexural strength, freeze–thaw durability, and water absorption tests were all conducted. Based on the results of the tests, an appropriate sludge concentration has been determined.

Unified, simple and decentralized treatment process for synthetic and real-time dye contaminated wastewaters

The aim of this study is to develop a simple, economical and effective treatment scheme to treat effluents from small scale textile dyeing units and tanneries, which have been set up in rural areas. The physicochemical properties of real time effluents procured from these industries were analysed. The workflow required for treating these effluents were ascertained by preliminary tests carried out on synthetically created solutions. A novel treatment scheme for tannery and textile dye effluents sludge volume reduction by the use of sodium hypochlorite was identified. Effective methods for the safe disposal and recycling of all the by-products generated from different steps were discussed. The proposed scheme was successfully able to decolourize and detoxify both the tannery and textile dyeing effluent with over 90% removal of both COD and BOD. The impacts of the treatment scheme on 14 different effluent parameters were reported. The methodology developed in this study may be utilized to construct simple localized treatment units for handling effluents in isolated rural areas. This preliminary treatment at the source, will help in the reduction of the load on the local treatment plants and prevent their choking.

Application of activated effective microorganism, mudball and biosand filter for the treatment of dye wastewater

A study was carried out to evaluate the application of Activated Effective Microorganisms (AEM) solution and EM Mudballs (mixture of soil, rice bran, and EM) to wastewater generated from wool and cotton dyeing unit at Kumbeshwar Technical School (Lalitpur, Bagmati Province, Nepal). Furthermore, the AEM treated wastewater was treated through a Biosand filter as a final treatment and polishing step before discharge in a nearby sewerage system. The wastewater samples collected for 27 days were analyzed for the wastewater quality parameters such as pH, Electrical Conductivity (EC), Total Solids (TS), and Chemical Oxygen Demand (COD) using the standard methods. The average values of pH, conductivity, COD, and TS after the EM combined with Biosand (final) treatment were observed to be 7.49±1.15, 1.39±0.25 mS/cm, 1,669.4 ±858.14 mg/L, and 264±25.29 mg/L, respectively. TS and COD removal were observed to be 43.97±22.3% and 15.26±10.06%, respectively. The results show that the dye wastewater is difficult to remove by a simple biological process like the addition of EM. Combined EM and biosand filters can be an inexpensive way of treating industrial effluents. However, the existing treatment system needs to be optimized by the integration with the proper EM: water: molasses ratio, optimal feeding time and design, hydraulic retention time, solids retention time, organic loading rates in EM reactor, and COD/BOD ratio in wastewater among other important components to meet the national effluent discharge requirements.

Phytoremediation Potential of Freshwater Macrophytes for Treating Dye-Containing Wastewater

Phytoremediation is a promising green technology for the remediation of various industrial effluents. Notably, aquatic plants are widely applied to remove dyes and toxic metals from polluted environments. In the present study, the phytoremediation potency of aquatic macrophytes such as Pistia stratiotes L, Salvinia adnata Desv, and Hydrilla verticillata (L.f) Royle were assessed based on the removal capability of pollutants from dyeing effluent. Physicochemical characterizations were carried out for industrial wastewater collected from a cotton material dyeing unit located in the Karur District of Tamilnadu, India. The physicochemical characteristics of the dyeing effluent, such as color, odor, pH, total dissolved solids (TDS), alkalinity, acidity, chloride, sulfate, phosphate, nitrate, chemical oxygen demand (COD), fluoride, and toxic metal levels were determined. The core parameters such as total dissolved solid (TDS), chemical oxygen demand (COD), and chloride level were determined and found to be 6500 mg/L, 2400 mg/L, and 2050 mg/L, respectively, which exceeded the regulatory limit prescribed by the Central Pollution Control Board of India. The levels of toxic metals such as Hg, Ni, and Zn were under the acceptable concentration but Cr and Pb levels in the dyeing effluent were a little bit higher. The effluent was subjected to treatment with Pistia stratiotes L, Salvinia adnata Desv and Hydrilla verticillata (L.f) Royle separately. After the treatment, the toxic metal results were recorded as below detectable levels and the same results were obtained for all three aquatic plants samples used for treatment. Among the three plants, P. stratiotes L efficiently removed 86% of color, 66% of TDS, 77% of COD, and 61.33% of chloride. The variation in phytochemicals of the macrophytes was studied before and after treatment using GC–MS which revealed the reduction of ascorbic acid in the plant samples. The toxic effect of treated effluent was investigated by irrigating an ornamental plant, Impatiens balsamina L. The plant biomass P. stratiotes L obtained after the treatment process was subjected to manure production and its nutrient quality was proved, which can be applied as a soil conditioner. Among the aquatic plants, the results of P. stratiotes L indicated a higher remediation potential, which can be used as an ecologically benign method for treatment of industrial effluents and water bodies contaminated with dyeing effluents.

Effect of rinse cycle softener on water vapour transmission of cotton and polyester

The current paper aims at determining the effect of rinse cycle softener treatment on water transmission behavior of fabrics made with 100% cotton and polyester. The research work was conducted at Nishat Mills Limited (Dyeing and Finishing Unit). Two groups of samples were formulated. One group was given rinse cycle softener treatment and the other group was not treated with any softener treatment. Both groups were evaluated for their water vapour transmission by following test standard given by American Society for Testing and Materials ASTM E-96 at various washing intervals. The results depicted that rinse cycle treated fabrics had significantly decreased the water vapour transmission through their structure in cotton fabrics with increasing washing intervals. Whereas, no significant difference was observed for polyester fabrics. Moreover, fabrics treated with no softener treatment had increased the water transmission values for both groups. Findings of the study can be beneficial for the consumers to make a decision about the use of fabric softeners in hot climate by considering their change in structure or appearance of fabrics. Keywords: Cotton; No Softener Treatment; Polyester; Rinse Cycle Softener; Washing Interval; Water Vapour Transmission http://dx.doi.org/10.19045/bspab.2020.90258

Remediation of textile effluents for water reuse: Decolorization and desalination using Escherichia fergusonii followed by detoxification with activated charcoal

Textile effluents contain high levels of pollutants of different categories like dyes, metal salts, acids, bases and microorganisms. Remediation of textile effluents is often challenging because of its composition, which also varies between dyeing units. In this study, we demonstrate the novel use of a waste-water bacterium, Escherichia fergusonii, in the effective remediation of textile effluents. The bacteria application efficiently caused a reduction of color (98.4%), total dissolved solids (75%), sulphates (87%), bicarbonates (83%), chlorides (64%), calcium (84%), and chemical oxygen demand (81%) of the textile effluents. The bacteria-treated effluents were further disinfected and detoxified by treating with rice husk activated charcoal. After the charcoal treatment, the chemical oxygen demand decreased further by 11.5% and biochemical oxygen demand decreased by 85%. The effluents remediated using the two-step process were subjected to toxicity assays using zebrafish (Danio rerio) model. The textile effluents treated using Escherichia fergusonii, followed by activated charcoal were found to be non-toxic and suitable for reuse for domestic applications. Thus, we present here, a simple, less energy-intensive, economic, two-step process as a complete solution for textile effluent treatment. The results of this investigation can be used to simplify the remediation process of textile effluents in common treatment plants as well as the individual dyeing units.

Bioefficacies of microbes for mitigation of Azo dyes in textile industry effluent: A review

In recent years, India has emerged as a promising industrial hub. It has a cluster of textile, dyeing, and printing industries. The adjoining rivers/water bodies receive mostly untreated discharge from these industries. Textile industrial effluent contains various contaminants (dyes, heavy metals, toxicants, and other organic/inorganic dissolved solids) that alter the physico-chemical properties of adjoining land and waterbodies in which it is discharged, thereby degrading the water quality and subsequently affecting the landscapes in the vicinity. This ultimately affects the flora and fauna of the locale and has adverse effects on human health. Out of the total dyes (approximately 10,000 dyes) exploited in the textile dyeing and printing units, azo dyes possess a complex structure and are synthetic in origin. They contribute nearly 70% to the total effluent discharge. Biological processes are based on the ability of inhabiting indigenous microorganisms in these contaminated environments to tolerate, resist, decolorize/degrade, and mitigate the recalcitrant compounds. Exploring microbes with higher efficacy of azo dye degradation can reduce the amount of chemical discharged from the process. The present review explores the potential of microbial diversity for the development of an effective bioremediation approach. The review also includes the impact of azo dyes on the flora and fauna, as well as conventional and microbe-assisted nanoparticle technology for treatment of the textile wastewater targeting the degradation of dye contaminants.

Textile wastewater discoloration by Fenton oxidation process

Treating industrial wastewater by advanced oxidation processes, is a recent interest primarily for decolorization of aqueous solutions containing dyes. The application of the Fenton reaction is one of these processes, bleaching liquid discharges after a textile dyeing unit in the city of Marrakech, Morocco, which are non-biodegradable, using oxidation by Fenton's reagent has shown its ability to degrade the dyes in water to carbon dioxide, water, and other harmless products. In this study a serie of pure dyes mineralization experiments used in the dyeing process, such as: the Bezaktiv BLUE-SR, the NOVACRON® Red FN-R, and the NOVACRON®SCALE TFN-6G, and a global liquid discharge containing dyes and chemical additives. Fenton's method is effective at pH = 3, as a result, we had a total discoloration for the three pure colors, and up to 47% to the overall rejection for 60 minutes at room temperature, and 100% when the temperature was increased to 60 °C. The presence of chemical additives disadvantage Fenton oxidation.