Eco-Dyeing of Wool-Blend Fabrics with a Natural Lac Dye: Comparison of Dyeing Processes and Treatment–Reuse of Dyeing Wastewater

Abstract

Sustainable textile production requires ecoengineering solutions that integrate natural colorants, process optimization, and circular water management. In this work, wool-blend fabrics (45% wool/55% polyester) were dyed with a lac-based natural dye using exhaustion, pad-dry, and pad-batch processes, aiming to support ecodesign strategies for lower-impact textile products. Dyeing performance was assessed through colorimetric analysis and color fastness tests. Among the tested routes, exhaustion dyeing provided the best overall balance between color development and fastness properties. The wastewater generated during the exhaustion process was subsequently treated by electrochemical oxidation using a boron-doped diamond anode, as an ecoengineering approach for effluent reclamation and reuse. The treatment reduced the organic load and color of the eco-dyeing wastewater, improving its suitability for partial replacement of fresh water in new dyeing cycles. Reuse assays carried out with a 50:50 mixture of treated effluent and fresh water produced fabrics with only a slight color difference compared with those dyed with fresh water, while maintaining comparable color strength and very good washing and rubbing fastness. These results demonstrate the feasibility of combining natural dyeing, advanced electrochemical treatment, and wastewater reuse as an ecodesign-oriented strategy for circular and more sustainable wool-blend textile processing.

Keywords: Sustainable Textile Processing, Textile Eco-Design, Natural Dyes, Wastewater Reuse, Electrochemical Oxidation, Eco-Dyeing Wastewater

DOI: 10.54941/ahfe1008191