A novel environmental friendly and sustainable process for textile dyeing with sulphur dyes for cleaner production

This investigation herein primarily focuses on developing a new textile dyeing process with sulphur dye class at room temperature using bacterial Lysate. Sulphur dyes are applied on cotton to produce dark shades at a lower cost, primarily providing excellent colour fastness, except against chlorinating agents. The insoluble sulphur dyes, like vat dyes, are first reduced and then applied as soluble leuco compounds that need to be kept under alkaline conditions, along with a reducing agent. The conventionally followed method of dying process involves the process of reduction of dyes using hazardous chemicals as reducing agent and alkali at higher temperature as well as subsequent dyeing at higher temperatures (60–80 °C) varying with the nature of dyes and processes. It eventually eliminates traditional heating arrangements and achieving easier control of the dyeing process at room temperature than at high temperatures. This investigation compares the newly designed processing route with the followed traditional process in the context of exhaust dyeing and rope dyeing methods with padding mangle. In addition, it involves in substituting the conventional reducing agent i. e. sodium sulphide partially with sodium hydrosulphite for sulphur dyeing. In nut-shell, this process comprises of reduction of dyes in the presence of an alkali agent, a reducing agent and a catalytic agent, wherein the reducing catalytic agent is a bacterial Lysate, establishing it to be environmentally viable, energy and cost effective, and sustainable dying process along with promising improvement quality in terms of dye uptake and comparable fastness properties.