Eco-friendly acid dyeing of silk and wool fabrics using Acid Violet 49 dye.

The effluent load from textile industries has forced traders and industrialists to use sustainable tools that not only save energy, money, and labor but also make the process cleaner. The purpose of this study is to improve the dyeing of proteinous fabrics using Acid Violet 49 dye under microwave radiation. Aqueous and acidic dye solutions were prepared and treated with MW radiations for up to 10 min. MW treated and untreated dye solutions were used to color treated and untreated fabrics to observe color yield. It has been found that dyeing of irradiated silk at 65 °C for 35 min, using 55 mL of irradiated dye solution containing 1 g/100 mL salt, has given excellent results. Whereas good color characteristics are obtained if irradiated wool fabric is dyed at 85 °C for 55 min, using 55 mL irradiated dye solution using 1 g/100 mL salt. Physicochemical analysis reveals that MW rays have physically modified the fabric without altering its chemistry. ISO standard methods employed for colorfastness show that under optimal conditions, the color developed is fast; statistical analysis shows that the dyeing process has given significant results. It is concluded that MW rays have excellent potential to improve acidic dyeing of proteinous fabric under mild conditions which show that the utilization of MW rays is a cost-, time-, and energy-effective process.

Assessment of wild turmeric-based eco-friendly yellow natural bio-colorant for dyeing of wool fabric.

The current study has been designed to observe the coloring efficacy of wild turmeric-based natural yellowish colorant for wool dyeing under microwave (MW) treatments. Extracts and fabrics have been exposed to MW treatment for up to 10 min. Surface morphology and changes in the fabric's chemical nature before and after radiation have been studied through SEM and FTIR, respectively. The results obtained after a series of experiments show that using 45 mL of aqueous extract (pH = 5) in the presence of 1.5g/100mL of table salt as an exhausting agent at 75°C for 45 min has displayed outstanding color depth (K/S) onto microwave-treated wool fabric. On applying biomordants, it has been found that acacia extract (1.5%), pomegranate (2%), and pistachio extracts (1.5%) before dyeing, whereas acacia (1%), pomegranate (1%), and pistachio extracts (2%) after dyeing, have shown colorfast shades of high strength. Comparatively, salts of Al (1.5%) and Fe (1%), and T.A (2%) before dyeing, while salts of Al (1%) and Fe (1.5%) and T.A (1.5%) after dyeing, have given the best results. Generally, it has been originated that salt of Fe (1.5%) as a post-chemical mordant and pomegranate extract (1.5%) as a post-bio-mordant have displayed wonderful color strength. It very well may be inferred that MW treatment, being naturally protected, has just superior the varying strength of colorants on wool fabric. Adding biomordants has transformed the strategy into a more sustainable one.

Sustainable eco-friendly extraction of yellow natural dye from haar singhar (Nyctanthes arbor-tritis) for bio coloration of cotton fabric.

The revival of natural dyes in different walks of life is due to stringent environmental standards imposed by many associations. For current studies, flowers of haar singhar (Nyctanthes arbor-tritis) has been chosen for bio-dyeing of cotton fabric using microwave irradiation techniques. For this purpose, liquid extracts and fabrics were exposed to microwave for 5 min at various conditions. These treated and un-treated dye extracts obtained in respective media were employed to dye the radiated and non-radiated cotton fabrics. The characterization of extract and untreated and undyed irradiated fabrics samples was done through FTIR. Different dyeing variables were optimized under CCD response surface methodology as a statistical tool. With the introduction of new shades and improvement of colorfastness properties, different concentrations of sustainable chemical and bio-mordant were employed. All dyed cotton fabrics were exposed to CIE-color space system for estimation of color coordinates and color strength by using spectra flash SF600 and to rate colorfastness properties using ISO standard methods for light, dry and wet rubbing, washing fastness. Cotton fabric was dyed with haar singhar flower extract of 7 pH from 4 g of powder, using 1.5 g/100 mL salt solution at 60 °C for 30 min. To get acceptable shades, aqueous extract after microwave treatment for 4 min provided excellent color strength. Pistachio (K/S = 3.6342) is a bio-mordant with great results, and aluminum (K/S = 4.8205) is a chemical mordant with outstanding results. It is found that green methods for isolation of colorant and green mordants for getting new shades should be employed.