Bleached Fabric Research Articles

Modelling Anodic H2O2 Accumulation in Alkaline Water Electrolysis with Experimental Validation

Hydrogen peroxide (H2O2) is a high value commodity chemical used as a green oxidant in industries such as paper milling and textile bleaching, and is currently produced by the anthraquinone oxidation process. The anodic co-production of H2O2 during alkaline water electrolysis has gained interest as a sustainable alternative for anthraquinone oxidation. However, electrochemical H2O2 production is often studied with idealized laboratory setups to determine the H2O2 formation kinetics. In this work, we perform the reaction using a flow cell with separately recirculating anolyte and catholyte. We then fit the H2O2 accumulation data to an analytical model that we derive based on mole balances that accounts for anodic generation, anodic oxidation, and bulk disproportionation of H2O2, as well as anolyte reservoir volume and anode chamber volume. We performed experiments to derive values for maximum H2O2 production at 300 mA cm-2, with values of 0.540 mmol s-1 for anodic generation of H2O2 (FEH2O2 = 58%) and 0.416 min-1 for anodic oxidation of H2O2, with a bulk disproportionation rate constant of 1.85 × 10−3 min-1. We successfully applied our model to two sources in literature to derive values for their systems as well. In all cases, the contribution of anodic oxidation of H2O2 was found to be the larger loss mechanism in comparison to bulk disproportionation. Figure 1

Effect of Dhupana (medicated fumigation) on the microbial concentration in the indoor air in Kumaragara (pediatric OPD and IPD): an experimental study

Abstract Introduction: Bioaerosols causing infectious diseases are a major concern for the environmental safety in hospital indoors. Chemical fumigation used for controlling infectious bioaerosols leads to several health hazards such as allergic reactions, hyperbilirubinemia, carcinogenicity, and toxicity. Corrosion of metal surfaces, bleaching of fabrics, risk of accidental consumption, high cost, unpleasant odor, flammability, and formation of toxic gases are other concerns. In Ayurveda, Dhupana (medicated fumigation) is advocated for controlling invisible agents capable of disease transmission. It can be a safer alternative to chemical fumigation. However, many ingredients of classical Dhupana preparations are rare or impractical to use; hence, a novel “Shodashanga Dhupa” (16-ingredient fumigation preparation) was formulated using easily accessible ingredients of classical Dhupana formulations. Materials and Methods: The antimicrobial and antifungal activities of Shodashanga Dhupa were ascertained by enumerating colony-forming units (CFUs) in the passive air samples obtained from hospital rooms before and after 1 h of Dhupana. These samples were collected on suitable agar media, and the settle plate method was carried out. Results: There was improvement in the Index of Microbial Air Contamination and a statistically significant reduction in bacterial CFUs in the pediatric outpatient department (P = 0.000218) and in the Panchakarma therapy room (P = 0.000218). There was a statistically significant reduction in fungal CFUs (P = 0.0137) in the pediatric outpatient department and in the Panchakarma therapy room (P = 0.00109) after 1 h of Dhupana. Conclusion: The study suggests that fumigation with common herbs and spices is effective in decreasing bacterial and fungal bioaerosol concentration in the indoor air of hospital rooms, and it can be used as an economical, hassle-free, and safe method of disinfection.

Construction of novel tandem reaction system coupling H2O2 production with in situ bleaching over Au/TiO2 photocatalyst with different metal-support interactions

A novel tandem reaction system formed with H2O2 production and in situ fabric bleaching reaction was firstly designed and constructed with Au/TiO2 photocatalyst. Results showed H2O2 generated in situ achieved high-efficiency fabric bleaching under the sunlight excitation, thus successfully constructing a ready-to-use system.·OH was confirmed as the main active specie in the simultaneous fabric bleaching reaction. Herein, to ensure the sufficient H2O2 production is a key factor. The different intensity of strong metal-support interaction (SMSI) was introduced into Au/TiO2 by regulating the calcination atmosphere to boost the H2O2 yield. H2/Ar calcination atmosphere imparted Au/TiO2 the SMSI effect to make H2O2 yield exceed that of counterpart under air atmosphere after 6 h of continuous reaction. The controllable capsulating overlayer on Au NPs provided relatively fewer exposed Au active sites to balance the H2O2 generation and decomposition rates, thus giving a better final yield. This work not only offer a novel path to improve H2O2 generation performance,but also propose new ideas for realizing in situ bleaching using sunlight as driving force and cleaning production of textile printing and dyeing industry.

Towards Sustainable H2O2 Photogeneration: Advancements, Challenges, and Future Prospects

AbstractHydrogen peroxide (H2O2) has emerged as a versatile and environmentally friendly oxidant, showing wide applications in diverse sectors such as fine chemical synthesis, waste stream treatment, precious metal extraction, and textile bleaching. With an escalating demand, H2O2 has now become one of the most essential chemicals worldwide. Efficient photocatalytic generation of H2O2 from water (H2O) and oxygen (O2) has been a long‐standing challenge, presenting a promising prospect to replace existing production methods. This review presents a framework aimed at achieving highly efficient and continuous H2O2 production via photocatalysis. The key aspects include photocatalyst design, selectivity for redox reactions, stability issue and reactor design. Through a comprehensive inspection and comparison of state‐of‐the‐art research, the most viable pathways for H2O2 photogeneration are identified, ensuring optimal solar‐to‐fuel conversion efficiency and high selectivity for target products. The ultimate goal is to establish H2O2 photogeneration as a sustainable and efficient method for producing this valuable chemical, contributing to a greener and more sustainable future.

The investigation of the effect of sodium chlorite and phosphonic acid catalysts on cotton bleaching process conditions

Today's environmental and living conditions necessitate reconsideration of traditional cotton fabric bleaching processes. For this reason, it is very important for the environment and the economy to obtain higher whiteness values by using less water and chemicals in bleaching. Sodium chlorite (NaClO2), the source of chlorine dioxide (ClO2) as the most important disinfectant, which gained popularity and availability during the COVID-19 pandemic, is an appropriate oxidant for the purpose. Using NaClO2 as bleaching agent has significant advantages, such as reducing the amount of washing proses and increasing of cotton strength. Another advantage of this reagent is that it causes less fabric weight loss than other reagents. Therefore, the present work was intended to improve the process conditions (different temperatures, concentrations, and times) of bleaching of cotton fabric by using NaClO2. Optimum temperature and time were determined as 30 min at 65 °C and 30 min at 85 °C, and a high whiteness index (W.I.=88) was obtained by using phosphonic acid (HEDP). Moreover, the tensile strength, weight loss and morphologies of the samples were examined. It has been observed that sodium chlorite causes little damage to cotton fibers and requires less water for rinsing since it does not form alkaline residues.

Challenges and opportunities in product development using natural dyes

Dyeing is a crucial textile technology procedure and one of the most enjoyable Textile Arts. Dyeing is an ancient art form that predates our civilization. All over the world the coloring of textile material is done with bleached fabric using natural and synthetic dyes. Coloring with natural materials is now commonly used as a supplement to hand spinning, knitting, and weaving. This study aims to compare the effluent properties of synthetic and natural dyes. Additionally, a product was created utilizing natural dyes because they are safe for the environment.This research article compares effluent parameters for natural and artificial dyes used for dyeing cotton fabrics, with a focus on fastness attributes, because while colouring the textile materials not all dyes are transfer, around 10-15% of dyes will remains in dye bath itself. When this effluent discharge, it is intensely colorful and aesthetically unpleasant and it will produce environmental problems.

Eco-Friendly Bleaching of Cotton Fabrics Without Heating Using Direct Process Water in the Presence of Sodium Chlorite and Phosphonate

ABSTRACT A large amount of chemicals, water and energy are used during the bleaching of raw cotton fabrics. For this reason, it is extremely important for economic and ecological aspect to develop eco-friendlier bleaching technology that eliminates the need for heat energy, process water, and wetting agent in the bleaching of these fabrics. Here, we report on green approach for industrial-scale bleaching with sodium chlorite (NaClO2) in presence of phosphonates (HEDP), which is used as both wetting agent and pH regulator and contributes to the high whiteness of fabrics. In bleaching, the process water was used in ambiant temperature as flote without any heating process, thus reducing the energy requirement significantly. In the measurements, it was observed that the whiteness value (W.I. = 72.6) obtained after 8.0 h bleaching at 20°C which was very close to the whiteness value (W.I. = 74.2) of reference W-1 fabric. Also, it has been confirmed that cotton fabrics bleached with NaClO2 have higher strength values, less damage, and residue on the fabric compared to reference fabrics, as well. This study showed that cotton fabrics can generate a small amount of wastewater and can be successfully bleached in the presence of NaClO2 without the need for any heating energy.

Effect of sub lethal concentrations of textile bleaching effluent in the total protein content in the fish, Cyprinus carpio

Proteins can be expected to be involved in the compensatory mechanism of stressed organisms. Toxic effect of treated textile bleaching effluent on the fish Cyprinus carpiowas assessed. Alteration in the protein content in muscle, liver, gill and intestine was determined after exposure to sublethal concentrations of the effluent for a period of 28 days. Data showed that total protein content was decreased in all test tissues compared to control. Results indicated the toxic nature of the effluent.

Alteration of lipid content in the fresh water carp, Cyprinus carpio under the toxic stress of industrial effluent

Contamination of aquatic ecosystems by industrial effluents causes harmful effects on health, growth, survival of aquatic animals like fishes which serves as a useful model for assessing the effect of chemicals mixed in the aquatic environment. Present study investigated the effect of sub-lethal concentrations (1.5%, 2 and 2.5%) of the treated textile bleaching effluent on the total lipid content in muscle, gill, liver and intestine of Cyprinus carpioafter exposure to 28 days. A significant decrement in total lipid content suggested that lipid might have utilized for the energy demand under the condition of stress.

A Polyimide-Based Photocatalyst for Continuous Hydrogen Peroxide Production Using Air and Water under Solar Light

A Polyimide-Based Photocatalyst for Continuous Hydrogen Peroxide Production Using Air and Water under Solar Light

Membrane Based Ultrafiltration of Toxic Effluent to Combat Groundwater Crisis

The paper observe and tries to evaluate the character of effluents generated from fabric bleaching and dyeing factories positioned at Kalikapur region beneath the Maheshtala region, West Bengal, India and to offer a sustainable control of surface water sources thru putting in CETPs with 0 liquid discharge plants. Effluents from medium, small and tiny factories of this place are producing 2000 MLD. Studies with forty small scale units for 4 years (2012—2016) positioned on this region exhibited following implied values of various physic-chemical variables: pH: 9, BOD: 608 mg/l, COD: 1824 mg/l, TDS: 6410 mg/l, TSS: 926 mg/l and hazardous metals which include Pb: 0.43mg/l, Cr : 0.031 mg/l, Zn: 0.74 mg/l, Ni: 0.07 mg/l and Cd: 0.03 mg/l. These values exceeded the usual permissible limits stipulated through FAO (1985) and WHO (2003). The wastewater encumbered with poisonous hint metals is adversely affecting the surroundings and human fitness and additionally degrades the best quality of each surface and groundwater and constantly lowering the level of underground water aquifer.

Bleaching of Jute-Cotton blend fabric with Peracetic acid for deep dyeing

The purpose of this study was to introduce sustainable bleaching of jute-cotton blend (Juton) fabric with Peracetic acid instead of conventional peroxide bleaching agents for the deep dyeing process. Juton was bleached with peracetic acid by varying the process conditions including temperature, pH, treatment time,concentration and the dyeing properties, fastness properties were investigated in a comparative manner. In addition, the physical properties of treated fabrics such as tensile strength, elongation, weight loss and the chemical changes of bleached fabrics were evaluated by using FT-IR. The morphological surface changes of bleached fabric were confirmed by SEM. Peracetic acid and hydrogen peroxide bleaching effluents were analyzed by measuring BOD, COD, TDS and DO values. The highest color strength was obtained at 70̊C,using neutral pH (7), concentration 20 mg/L in 80 min treatment time based on peracetic acid bleaching agent for Juton fabric. Peracetic acid bleaching of Juton fabric was found to be higher tensile strength and elongation than H2O2 bleaching. Peracetic acid bleaching effluent exhibited lower BOD, COD, TDS and higher DO than hydrogen peroxide bleaching effluent. Moreover, peracetic acid bleaching provided higher fastness to washing,light and rubbing than hydrogen peroxide bleaching.

3d Transition-Metal-Mediated Columbite Nanocatalysts for Decentralized Electrosynthesis of Hydrogen Peroxide.

Decentralized electrosynthesis of hydrogen peroxide (H2 O2 ) via oxygen reduction reaction (ORR) can enable applications in disinfection control, pulping and textile bleaching, wastewater treatment, and renewable energy storage. Transition metal oxides are usually not efficient catalysts because they are more selective to produce H2 O. Here, it is shown that divalent 3d transition metal cations (Mn, Fe, Co, Ni, and Cu) can control the catalytic activity and selectivity of columbite nanoparticles. They are synthesized using polyoxoniobate (K7 HNb6 O19 ·13H2 O) and divalent metal cations by a hydrothermal method. The optimal NiNb2 O6 holds an H2 O2 selectivity of 96% with the corresponding H2 O2 Faradaic efficiency of 92% in a wide potential window from 0.2 to 0.6V in alkaline electrolyte, superior to other transition metal oxide catalysts. Ex situ X-ray photoelectron and operando Fourier-transformed infrared spectroscopic studies, together with density functional theory calculations, reveal that 3d transition metals shift the d-band center of catalytically active surface Nb atoms and change their interactions with ORR intermediates. In an application demonstration, NiNb2 O6 delivers H2 O2 productivity up to 1 molH2O2 gcat -1 h-1 in an H-shaped electrolyzer and can yield catholytes containing 300× 10-3 m H2 O2 to efficiently decomposing several organic dyes. The low-cost 3d transition-metal-mediated columbite catalysts show excellent application potentials.

Air Permeability and Water Vapor Resistance of Differently Finished Cotton and Cotton/Elastane Single Jersey Knitted Fabrics

ABSTRACT This study investigates the knitted fabrics’ air permeability and water vapor resistance as complex phenomena of the interaction between the fiber nature, fabric structural characteristics and, different wet processes. Bleaching and dyeing together with the content of elastane are the main factors determining fabric structural characteristics. 100% cotton fabrics have a higher intensity of warm/cool feeling since they have higher air permeability than elastane containing fabrics. The air permeability and water vapor resistance of elastane containing fabrics decreased after the wet processes, whereby the bleached knitted fabrics showed higher air permeability and lower water vapor resistance than dyed. Decreased air permeability and increased water vapor resistance of softened elastane containing fabrics are governed by the cationic softener pick-up mechanism. Namely, the cationic softener is deposited on the yarns’ surfaces; its hydrophobic carbon ends repel from each other. This acts as a barrier for air which contributes to an increase in the fabric water vapor resistance. The softened dyed knitted fabrics have lower air permeability and slightly higher water vapor resistance than softened bleached fabrics which may be attributed to the interaction between reactive dyestuff and cationic softener. The comfort properties quality of finished knitted fabrics decreased with elastane incorporation and with softening.

Eco-Friendly Cotton/Linen Fabric Treatment Using Aqueous Ozone and Ultraviolet Photolysis

Chemicals for the scouring and bleaching of fabrics have a high environmental load. In addition, in recent years, the high consumption of these products has become a problem in the manufacture of natural fabric products. Therefore, environmentally friendly, low-waste processes for fabric treatment are required. In this paper, we discuss the bleaching of fabrics using advanced oxidation processes (AOP). These processes use electrochemically generated aqueous ozone and ultraviolet (UV) irradiation to achieve bleaching. However, colour reversion often occurs. In this study, we suppressed unwanted colour reversion by treatment with rongalite. After treatment, changes in fabric colour were determined by measuring the colour difference and reflectance spectra. The best bleaching effect was obtained when ozone and UV irradiation treatments were combined, achieving results similar to those of a conventional bleaching method after 60 min of UV irradiation. In addition, the AOP treatment resulted in the simultaneous scouring of the fabric, as shown by the increased hydrophilicity of the fabric after AOP treatment. Thus, this AOP process represents a new fabric bleaching process that has an extremely low environmental impact.

Ozone in Textile Bleaching: Roadblocks and Path Forward

Ozone in Textile Bleaching: Roadblocks and Path Forward

Optimisation of the Production and Bleaching Process for a New Laccase from Madurella mycetomatis, Expressed in Pichia pastoris: from Secretion to Yielding Prominent.

Laccases are polyphenol oxidoreductases used in a number of industrial applications. Due to the increasing demand for these "green catalysis" enzymes, the identification and biochemical characterisation of their novel properties is essential. In our study, cloned Madurella mycetomatis laccase (mmlac) genes were heterologously expressed in the methylotrophic yeast host Pichia pastoris. The high yield of the active recombinant protein in P. pastoris demonstrates the efficiency of a reliably constructed plasmid to express the laccase gene. The optimal biochemical conditions for the successfully expressed MmLac enzyme were identified. Detailed structural properties of the recombinant laccase were determined, and its utility in decolourisation and textile bleaching applications was examined. MmLac demonstrates good activity in an acidic pH range (4.0-6.0); is stable in the presence of cationic metals, organic solvents and under high temperatures (50-60°C); and is stable for long-term storage at - 20°C and - 80°C for up to eight weeks. The structural analysis revealed that the catalytic residues are partially similar to other laccases. MmLac resulted in an increase in whiteness, whilst demonstrating high efficiency and stability and requiring the input of fewer chemicals. The performance of this enzyme makes it worthy of investigation for use in textile biotechnology applications, as well as within environmental and food technologies.

Two-Step Bleaching of Jute Yarn and Fabric Using Hydrogen Peroxide and Peracetic Acid

ABSTRACT Bleaching of jute has become essential for making white glossy fabric or base material for coloration intended for value added and diversified products. The conventional hot hydrogen peroxide bleaching process produces white fiber with high loss of tensile strength and impairing the feel. On the other hand newly developed peracetic acid bleaching of jute produces minimum loss of tenacity without impairing the feel but whiteness achieved is slightly low. Partial bleaching of jute was carried out using 25%, 50%, and 75% of the normal dose of bleaching agents and their whiteness index as well as tensile strength were evaluated. In all the cases hydrogen peroxide produced 5–8 grade higher whiteness in HUNTER scale while peracetic acid bleached sample retains higher tensile strength. So, two-step bleaching was carried out using hydrogen peroxide and peracetic acid following single-bath and double-bath processes. Two-step single-bath bleaching of jute fabric using 75% peracetic acid followed by 25% hydrogen peroxide bleaching treatment results in best effect with respect to optical and physical properties.

Improvement of the Quality of Cotton Fabric Through Functionalization of Tagetes minuta (TaMi) Dye

Non-functionalized and functionalized Tagetes minuta (TaMi) dye obtained using methanol and water showed varied fastness onto cotton fabric. Furthermore, HPLC profile of the methanol dye showed more peaks and hence was expected to be richer in secondary metabolites that impacted on the quality of the dye. This was confirmed from the IR spectrum which showed more functional groups from this dye as compared to the water dye. The functionalized methanol dye exhibited good fastness onto cotton textile and minimal bleaching effects, as compared to non-functionalized H 2 O and MeOH dye. Furthermore, the process involved the use of low quantities of the dye material/solution as compared to non-functionalized dye, hence resulting to less impact on environmental degradation. The colors of the textiles produced from the methanol functionalized dye were highly resistant to fading or running. The cotton fabric articles that were tri-mordanted at 80-90 °C and dyed using the functionalized dye exhibited uniform absorption of color of the dye and good fastness. Functionalization of the methanol TaMi dye was obtained by the reaction of the TaMi dye with 1,4-butanediol diglycidyl ether (BDDE). The alum tri-mordanted textile materials produced brighter colors of brown as compared to the singly alum mordanted fabrics. This is due to the tannin factor in tri-mordants that led to the brightening effect. Furthermore, longer duration of time for tri-mordanting might have had a greater impact to the brightness effect. Additionally, characterization of the dye obtained using the two solvents was done using HPLC and IR. The formed functionalized dye has many applications as colorants in textiles, paints, inks, plastics, cosmetic articles and electronic materials. Keywords: Cotton fabric, Tagetes minuta , dye, functionalized, 1,4-butanediol diglycidyl ether, colorants DOI: 10.7176/JNSR/11-16-02 Publication date: August 31 st 2020

Color consistency in the appearance of bleached fabrics.

Human observers are remarkably good at perceiving constant object color across illumination changes. However, there are numerous other factors that can modulate surface appearance, such as aging, bleaching, staining, or soaking. Despite this, we are often able to identify material properties across such transformations. Little is known about how and to what extent we can compensate for the accompanying color transformations. Here we investigated whether humans could reproduce the original color of bleached fabrics. We treated 12 different fabric samples with a commercial bleaching product. Bleaching increased luminance and decreased saturation. We presented photographs of the original and bleached samples on a computer screen and asked observers to match the fabric colors to an adjustable matching disk. Different groups of observers produced matches for original and bleached samples. One group of observers were instructed to match the color of the bleached samples as they were before bleaching (i.e., compensate for the effects of bleaching); another, to accurately match color appearance. Observers did compensate significantly for the effects of bleaching when instructed to do so, but not in the appearance match condition. Results of a second experiment suggest that observers achieve color consistency, at least in part, through a strategy based on local spatial differences within the bleached samples. According to the results of a third experiment, these local spatial differences are likely to be the perceptual image cues that allow participants to determine whether a sample is bleached. When the effect of bleaching was limited or uniformly distributed across a sample's surface, observers were uncertain about the bleaching magnitude and seemed to apply cognitive strategies to achieve color consistency.