Ecofriendly pretreatment of cotton knit fabrics by ultrasonic irradiation and reusing bath chemicals

Abstract

Bangladesh's cotton knit industries contribute significantly to the country's economy, accounting for more than 40% of total annual export. Efficient water use in knit dyeing might result in considerable water savings and environmental sustainability. Textile wet processing consumes a lot of energy (water, gas, and electricity), generates a lot of waste, and has significant chemical costs. The cotton knit fabric used in this study was pretreated and dyed utilizing ultrasonication at a lower temperature than conventional pretreatment and dyeing techniques in an attempt to establish ecofriendly wet processing in the textile industry. For pretreatment and dyeing, bath chemicals were reused 1–3 times, and several fabric attributes including whiteness index, weight loss (%), bursting strength, color fastness to light, washing, perspiration, and rubbing were tested and compared to the traditional method. By dying with reactive dyes, the feasibility of color matching using ultrasonic aided pretreated fabric with and without reusing bath chemicals was determined. The whiteness index of the low temperature sonicated scoured and bleached fabric was found to be acceptable, with relatively low weight loss; nevertheless, the bursting strength was found to be enhanced. Color fastness to light, washing, perspiration, and rubbing of ultrasonicated dyed knitted fabric at lower temperatures than conventional techniques were found to be comparable, showing that there was no color deterioration during ultrasonication. FT-IR spectroscopy and scanning electron microscopy (SEM) revealed no significant changes in the chemical composition of cellulose or the fabric shape of pretreated and dyed cotton knit fabric after ultrasonication.