Sustainable natural coloring potential of bitter gourd (Momordica charantia L.) residues for cotton dyeing: innovative approach towards textile industry

Sugar beet (Beta vulgaris L.) leaves as natural colorant for cotton dyeing using an ecofriendly approach toward industrial progress

In the industrial sector, vegetable residual materials have received attention in the production of bio-colorant for textile dyeing. The current research endeavor is centered on investigating the possibility of using sugar beet leaves as a natural source of dye for the purpose of dyeing cotton fabrics. Different extraction methods were utilized to isolate the bio-colorant present in sugar beet residual material, and the most favorable colorant yield was obtained using a 5% methanolic KOH solution. For optimal dyeing results, the cotton fabric performed dyeing for a duration of 45 min at a temperature of 60 °C, using a salt solution concentration of 6 g/100 mL and 50 mL of the extracted dye solution. Characterization of dye using Fourier transform infrared spectroscopy analysis confirmed the presence of quercetin in the leaf extract. For the creation of a range of color variations, mordants that were chemical in nature, such as tannic acid, iron sulfate, potassium dichromate, and copper sulfate, as well as mordants that were bio-based, such as onion peel, pomegranate peel, henna, golden shower bark, and turmeric, were employed in harmony. In comparison, the utilization of bio-mordants resulted in darker shades that exhibited enhanced color intensity and superior color fastness properties with the value of 4-5 for wash, 4 for wet rubbing, 4-5 for dry rubbing, and 4-5 for light. The findings of this study hold significant value in terms of ecofriendly waste management and contribute to advancements in the industrial sector by utilizing waste residual materials as a natural source of colorants.

Bio-mordants: a review

Due to the increasing pressure on environmentally friendly approaches and sustainable production processes, the textile dyeing industry has focused on natural colorants. Thus, the use of bio-mordants, which are biological materials, has become widespread as an alternative to metal salts, most of which are non-ecological, used in the application processes of natural colorants. In natural dyeing, dyers want to use mordant substances in the dyeing processes in order to both expand the color spectrum and improve the fastness properties. Conventional metal salts used in natural dyeing are made up of metallic ions, which, when released into the environment as wastewater effluent at the end of the dyeing process, cause major damage to the ecosystem. Many researchers have thought about using mordants derived from natural sources to address the environmental problem. This article is a review of the investigation of natural mordants used instead of metallic mordants in the process of coloring various textile materials with natural dyestuff sources. It has been determined that many substances, most of them herbal materials, are used as mordants. In this review, mordants, except for conventional metal salts, are examined under three main groups for a better understanding. These groups are as follows: (i) natural or bio-mordants, (ii) oil mordants, and (iii) new-generation and non-vegetable-based mordants. Here, researchers will find an overview of the most recent developments in green mordants as well as application techniques for a variety of mordants.

Isolation and identification of Methylobacterium komagatae and its application in textile industries

A light pink-coloured, rod-shaped, gram-negative bacterium isolated from an unproductive crude oil production area was considered as a sample for this study. The 16S rRNA gene sequence identified the isolate as Methylobacterium komagatae. Comparing the standard colour measurement values set by the International Commission on Illumination (CIE) method confirms the colourant produced by the biomass of this microorganism as a 'light pink' colouration. The energy-dispersive X-ray spectroscopy and High-Resolution Mass Spectroscopy process help in the structural elucidation of the sample. It indicates the presence of magnesium (Mg) as a central metal atom in the bacterial colourant, i.e. 'bacteriochlorophyll' (BChl) (MgC55H74N4O). The recovered bacterial colourant was applied to cotton fabric and cotton yarns to dye and examine their fastness quality. The result shows the cotton fabrics retained colourant in normal washing while it got reduced after detergent-based washing. Therefore, its fastness quality must be improved to equalise with current colourants.

Exploration of natural colourant of (Solanum melongena L.) brinjal plant residues for fabric dyeing: a novel approach towards textile processing

Natural products have become the main focus of mankind due to increasing environmental pollution. The current study was concerned with brinjal plant residues as a source of bio colourant for cotton dyeing. Various media have been employed for the extraction of colourant. Present studies illustrated that excellent colourant yield was obtained in 4% acidified methanol. Cotton fabric was dyed at 50 °C, for 55 min and showed optimised dyeing conditions. Varying chemicals and bio-mordants have been used to achieve elegant shade. Chemical mordanting results revealed that 2% FeSO4as pre-mordant, and 6% TA as post-mordant while in bio- mordanting, 8% of pomegranate peel extract as pre-mordant and 2% pomegranate peel extract as post-mordant indicated a darker shade to mordanted fabrics. Bio-mordanting gave darker shade, and fastness which revealed that bio-mordants have improved the fastness characteristics. FTIR results revealed the confirmation of flavonoids as a colourant for cotton dyeing.

A survey on the potential contribution of Reunion Island dye plant species diversity to the market demand for bioactive plant-based dyes and pigments

BACKGROUND

Proven toxicity and environmental burdens caused by artificial dyes have motivated dyeing industries to turn to natural alternatives. Plant-based dyestuffs are an interesting group of alternative crops. Reunion Island located in the Indian Ocean is the only European region in the southern hemisphere. It has a great number of assets to find new molecules in the abundant plant biodiversity. However, the dye-producing plants diversity in this island had not been documented to date.

METHODOLOGY

The assessment of the Reunion Island's plant biodiversity through the "PLANTIN" project allowed us to establish here the first ethnobotanical inventory of plants growing on Reunion Island which may have promising properties as a new alternative source of dyes or colorants for the industries. First, an ethnobotanical survey focused on the uses of plants traditionally used in dyeing was conducted on local stakeholders. Then, the importance of different criteria (e.g., endemicity, accessibility and cultivability, plant organs used for the extraction, industrial interests of the species, etc.) has been considered to establish a classification method of the species, to finally select the most interesting plants which have been further harvested and investigated for their coloring property and dyeing application on natural fibers.

RESULTS

The results showed that local people have accumulated traditional knowledge of dyeing plants, but that this approach had been discontinued in Reunion. The uses of 194 plant species potentially rich in dyes or pigments, belonging to 72 different families, with diverse botanical status (endemic, native, introduced or alien-invasive species) have been recorded. Then, 43 species were harvested and their coloring property were investigated. It demonstrated that dyes extracted from promising species, e.g., Terminalia bentzoe, Weinmannia tinctoria, Thespesia populnea, Erythroxylum laurifolium, Morinda citrifolia, Leea guinensis, Ochrosia borbonica, Danais fragrans, Terminalia cattapa, Casuarina equisetifolia, and Coccoloba uvifera, amongst others, could be used as new textile dyes. Their efficacy in the wool and cotton dyeing has been successfully demonstrated here.

CONCLUSION

These plant-based dyestuffs showed promising coloring properties with different shades that could meet industrial application requirement. It's an area that could promote local cultural inheritance, create opportunity for business and farmers, and that can make a significant contribution to preserving endangered native species by supporting reforestation schemes. Additional researches are in progress to evaluate the safety of these plant-based colored extracts, their chemical composition and biological activities.

Environmental friendly silk and cotton dyeing using natural colorant of Bougainvillea (Bougainvillea glabra) flowers: the sustainable approach towards textile industry

For the current study, Bougainvillea flowers as environment friendly sustainable source of plant-based natural dye have been selected as an alternative to toxic synthetic dyes for dyeing of cotton and silk. Natural colorant from Bougainvillea flowers (Bougainvillea glabra) was extracted using aqueous and acidic extraction media. Maximum colorant was extracted in aqueous medium, and further it was used for cotton and silk dyeing. The optimum values of the dyeing parameters including dyeing time, dye to liquor ratio and salt level as exhausting agent were found to be 30 min, 35-mL liquor ratio and 3.0 g for cotton and for silk 45 min dyeing time, 45-mL liquor ratio and 3.0 g exhausting agent in aqueous dye extract. Bio mordanting has been applied to attain a variety of color shades. The utilization of 3% of henna, 4% of turmeric for silk pre-mordanting and for post-mordanting turmeric at 3% and henna at 4% for silk gave a darker shade. For cotton bio mordanting, 2% turmeric rhizome powder, 3% henna leaves powder extract as pre-mordant and 2% turmeric, 3% henna as post-mordant has developed a variety of shade. Overall, it has been found that natural colorant from Bougainvillea flowers is the new dye source for bio-coloration of natural fabrics, and addition of bio mordants has made the process more calming and eco-friendly.

Microwave-assisted sustainable exploration of cocklebur leaves (Xanthium strumarium L.) as a novel source of distinct yellow natural colorant for dyeing cotton fabric

During current times, the use of bio-colorants attained public acceptance as a sustainable alternative to synthetic ones which in turn reduced the environmental contamination. The present study focused on the green, safe, and clean technology for the resurgence of natural colorant from cocklebur (Xanthium strumarium L.) leaves and their application to cotton fabric. Natural colorants were extracted by employing an eco-friendly microwave-assisted extraction process using an aqueous and alkaline medium. Dyeing of cotton fabric was carried out using irradiated and unirradiated cotton fabric with irradiated and unirradiated natural dyes of cocklebur leaves. The results of extraction experiments revealed that 4 min microwave-assisted alkaline extract exhibited significantly outstanding color strength onto microwave-treated cotton fabric compared to aqueous one. Further to investigate the optimum dyeing conditions for cotton fabric, various dyeing variables such as dyeing time, dyeing temperature, dye concentration, and exhausting agent were monitored and found a superior result using a dye concentration of 45 ml, for dyeing cotton fabric at 75 °C for 50 min in the presence of 4 g/100 ml of table salt. For improvement in color strength and color fastness properties, the effects of various bio-mordants, such as eucalyptus bark, acacia bark, turmeric rhizome, and onion shells, and chemical mordants (aluminum and copper) on dyed cotton fabric were also evaluated. It was also observed that cotton fabric dyed with alkaline extract of cocklebur leaves using bio-mordants as pre-mordants (4% acacia, 4% eucalyptus, 2% onion) and post-mordants (3% onion, 3% eucalyptus, 4% acacia) exhibited the highest color strength and various hues with acceptable colorfastness properties against light, washing, and rubbing in comparison to chemical mordants. The ISO standard for fastness also revealed that bio-mordanting has enhanced the rating from good to excellent in comparison to chemical mordants. The results provide ample scope for the extraction of yellow natural dye from the cocklebur leaves for eco-friendly coloration of fabrics using bio-mordants.