Study of the desorption of hydrolysed reactive dyes from cotton fabrics in an ethanol–water solvent system

Abstract

The factors influencing the desorption of hydrolysed dyes resulting from reactive cotton dyeings in an ethanol–water solvent system, including the volume ratio of ethanol to water, pH, and temperature, were investigated. The maximum desorption was achieved when the volume ratio of ethanol to water was optimised to 4:6. Desorption increased with an increase in pH and temperature. The kinetic curves of dye desorption at three different temperatures fit a two‐step kinetic model. The dye desorbability at 60 °C in an ethanol–water system was similar to that observed using conventional water washing in the presence of detergent at 95 °C. Findings suggest that wash‐off in an ethanol–water system can be considered as an alternative, more effective process for removing hydrolysed dyes from reactive cotton dyeings.

Preparation of certified reference materials for cotton fabric’s dye transfer inhibition performance test of household washing machines

“…Dye transfer is related to the structural characteristics and dyeing mechanism of cotton fibers, the stability of reactive dyes, and the influence of additives. [4][5][6] At present, Europe has released a relevant standard for testing the dye transfer inhibition performance of laundry detergents: the revised EU Ecolabel protocol for testing laundry detergents. 7 Also, some high-end washing machines are equipped with "color protection" and "dye transfer inhibition" washing procedures.…”

A Modified Hydrolysis Method of Decolorizing Reactive-Dyed Polycotton Waste Fabric and Extraction of Terephthalic Acid: A Perspective to Reduce Textile Solid Waste

“…The hydroxyl group can accelerate dye ionization and degradation by blocking dye molecule contact. Therefore, dye and fiber cannot interact again, and dye loss is enhanced during hydrolysis [42].…”

Removal of hydrolized reactive dyes from cotton fabric after dyeing

“…Na osnovu rezultata zaključili su da ekološko pranje primenom b-ciklodekstrina može se uspešno primeniti kod uklanjanja boja niske supstantivnosti, dok uklanjanje hidrolizovanih boja visoke supstantivnosti je slabije u odnosu na tenzide, zato što b-ciklodekstrin nema izražena svojstva kvašenja i dispergovanja. Hang i He su u nedavno objavljenoj studiji preporučili sistem etanol-voda kao efi kasnu ekološku alternativu za konvencionalno pranje pamuka nakon bojenja reaktivnim bojama [12]. Oni su ispitivali faktore koji utiču na desorpciju hidrolizovanih boja iz pamučnih tkanina u sistemu rastvarača koji se sastojao od etanola i vode, uključujući odnos zapremine etanola i vode, pH, i temperaturu.…”