Ecological approaches to textile dyeing: a review

Conventional dyeing processes currently practiced in the textile industry have a great environmental impact, mainly in relation to the quantity and pollution of water, use of toxic chemicals, atmospheric emissions, and high energy consumption. This study aims to discuss the relationship between the variables that involve conventional dyeing processes and environmental issues. It presents the mapping of the materials and emerging technologies for ecological coloration, specifically for the pretreatment and dyeing stages. Regarding pretreatment, it discusses biochemical (enzymes) and physical treatment (ultraviolet radiation, plasma, and ozone technology) approaches. With respect to the dyeing processes, it addresses ecological materials (natural dyes) and emerging technologies (such as plasma, supercritical CO2, AirDye®, ultrasonic, microwave, Nano-DyeTM, and electrochemical). Given the importance of ecological coloration, this study provides important reflections on the urgency of resolving issues related to barriers and economic viability in the implementation of the alternatives presented and demonstrates the need to develop educational projects to prepare fashion and textile professionals.This work was financed by Project UID/CTM/00264/2021 of 2C2T (the Centre for Textile Science and Technology), which is funded by national funds through FCT (Foundation for Science and Technology)