Low Impact Reactive Dyeing Methods for Cotton for Sustainable Manufacturing

Abstract

The reactive dyes, though result in higher fastness properties compared to other classes of dyes used in colouration of cotton fibres, lead to problems related to effluents predominantly due to unreacted and hydrolysed dyes during the reaction. Besides, use of higher amounts of salts added during the exhaustion (30-70�g/L) and fixation process (10-20�g/L) also result in higher COD levels in the effluents. Suitable modifications of dyes to improve the reactivity or to lower the hydrolysis and modification of substrates to have more reactive sites could provide a sustainable solution to such problems. Various scopes available for modifying the substrates suitable for reactive dye applications and different structural modifications carried out in the reactive dyes to reduce the environmental impacts are discussed in this chapter.