Sustainable dyeing of wool with natural dyes using ionic liquids and alum mordant

Abstract

This study explores the potential of using ionic liquids (ILs) and alum mordants to enhance wool dyeing with natural dyes, specifically Madder and Reseda lutea extracts. Wool fibers were treated with various concentrations of ILs (0 %, 1 %, 2 % o.w.f) and subsequently dyed at dyeing temperatures to evaluate improvements in dye uptake, color strength, and fastness properties. FTIR spectroscopy was used to assess chemical interactions between ILs and wool fibers, and SEM imaging provided insights into morphological changes. Color fastness was evaluated using ISO standard test methods. The results demonstrate that IL and alum treatments improve dye absorption and color strength, particularly at lower dyeing temperatures. Combined IL and alum mordant treatments significantly enhanced washing and light fastness, while mechanical evaluations showed that dyed wool retained acceptable tenacity and elongation, with only minor reductions. This study presents a more sustainable method for wool dyeing by integrating ILs and natural mordants, promoting energy-efficient, low-temperature processing. This approach aligns with the goals of sustainable textile manufacturing and offers an alternative to traditional dyeing practices.