Towards sustainable Rubia tinctorum L. dyeing of woven fabric: How life cycle assessment can contribute

Abstract

Bio-based dyes for textile dyeing have been widely studied on account of their environmentally friendly approach but in order to be considered as an eco-friendly dyeing concept, additional parameters need to be considered. The purpose of this study was to improve a textile (polyester) dyeing process with madder dye (Rubia tinctorum L.), from an eco-sustainable point of view. A life cycle assessment (LCA) has been performed to determine the environmental impacts associated with the dyeing process, at research lab-scale. The identified hotspots were: the solvent and energy use for madder dye extraction and the liquor:fabric ratio in the dyeing phase. Results showed that reduced impacts from both hotspots were needed in order to perform the best in all impact categories studied. Indeed, decreased solvent and energy consumption by ultrasound-assisted dye extraction reduced the global warming potential, photochemical ozone creation potential and air acidification, while minimized water consumption in the after-wash of the dyed fabric was a promising option for improvement in water depletion and eutrophication.