Reducing Wastewater in Textile Industry: Innovative Dying Approach

Abstract

The reduction of water pollution represents one of the priority topics of the EU’s goal to achieve climate neutrality by 2050. Herby textile industry is focused on developments in numerous environmental and social issues, including high emissions, high water and/or energy consumption and heavy pollution [1]. Coloured effluents from this industry disposed into natural ecosystems are responsible for about 20% of global clean water pollution [2]. The European Union aims to reduce textile waste and increase the life cycle and recycling of textiles as part of the plan to achieve a circular economy by 2050 by sustainable products and empowering consumers to participate in the green transition [2]. One of the main research topics connecting textile industry and waste water reduction is found in synthesis of eco-friendly dyes which are superior to their natural analogues due to the excellent dyeing capabilities and colour fastness properties. Among these, azo pyridine dyes gained attention for the simplicity of their preparation, good colour fastness, high tinctorial strength, thermal and optical stability [3]. Traditionally, applied as disperse dyes, they have low water solubility and are used for colouring mostly synthetic fibres. Recent findings showed that the introduction of the pyridinium ring into pyridone molecule resulted in enhanced water solubility of the dyes and improved affinity towards various natural and synthetic fibres, especially wool and cellulose diacetate fibres [4]. For the purpose of addressing environmental issues in the textile industry, in this work, two pyridinium-based azo pyridone dyes with improved solubility and affinity towards different fibres, are used for dyeing wool fabric. The results show that the same dyebath can be efficiently used multiple times, therefore reducing waste in the water while securing the optimizing dying. The obtained fabrics from different cycles are further characterized by K/S values while the residue of the dye in the wastewater was recorded using UV-Vis spectra.