Challenges in dyeing of cellulosics with reactive dyes and practical sustainable feasibilities

Abstract The present chapter briefly outlines some basic information about cellulosic fibers, history and chemistry of reactive dye development, different types of reactive dyes, method of application, ecological aspects of reactive dyes, unconventional dyeing methods for reactive dyes, sustainability challenges in the reactive dyes, current technologies for improvement of sustainability of reactive dyes, and feasibilities for improvement. Reactive dyes are a major class of dyestuffs used for the dyeing of cellulosic materials such as cotton and viscose. As the name implies, these dyes have the tendency to chemically react with hydroxyl group of cellulosic materials and form covalent bond, thereby producing good fastness properties to the dyed materials. These dyes produce brilliant colors with reasonable fastness properties, and for that reason they are the most preferred dye for dyeing of cellulosic materials. Cellulosic fiber-based clothing materials are expected to gain further importance due to the ocean plastic problem due to the release of nonbiodegradable microfibers released from synthetic fibers such as polyester and acrylic. Reactive dyes constitute more than 80% of the dyes that are used for dyeing cellulosic materials. Considering the sustainability of reactive dyeing of cellulosics, there are major issues such as requirement of huge amount of salt and alkali for exhaustion and fixation, formation of hydrolyzed dye during dyeing, and poor wet rubbing fastness. These issues lead to high dyeing cost coupled with higher effluent load during dyeing with increased treatment cost. The present chapter outlines the abovementioned challenges in the reactive dyeing of cellulosics and elucidates practical solutions to overcome them.