Industrialization has improved the economics of India by employing innumerable population. At the same time, environment is heavily polluted, both air and water. Thus, there is an urge to take care of environment by employing cleaner technologies in the field of textile wet processing. Reactive dyes are widely used to dye cellulosics because of their good wash fastness properties. However, the process of dyeing with reactive dyes is a pollution generating process and also energy and water intensive. One of the most serious ecological problems that arise from the reactive dye is the high salt content in the effluent. High sodium chloride or sodium sulphate concentration in the range of 50-100 gm/lit are required to increase their substantivity towards cellulose by decreasing the negatively charged barriers between the cellulose and dyes anions and also by reducing the solubility of the dye. Sodium sulphate increases the accumulation of the sulphate ions, which is associated with the increase in acidity of the water bodies. The high TDS caused by excess salt in the effluent affects the aquatic eco system. The dye fiber reaction in reactive dye is moderately efficient as the dye fixation varies from 50 - 90% depending on the application method, depth of shade and dye type. This unfixed or hydrolyzed dye also poses environmental hazards, as in some countries the discharge of some organohalogens is controlled and certain reactive dyes fall in this category. High organic load from the dye contributes to high COD and BOD, which remove oxygen from water. The unfixed and hydrolyzed dye contributes to AOX. To remove the unfixed or hydrolyzed dye, half of the cost of a typical reactive dyeing may be attributed to the washing stage and treatment of resulting effluent. During 1980's there was a revival of interest to develop techniques that would enhance the dyeability of cellulose with the reactive dyes and direct dyes by pretreatment with a variety of cationic products, usually based on nitrogen. Many such studies have been carried out on cotton to reduce the amount of electrolyte required and to increase the dye-fiber interaction.
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