Sustainable extraction and utilization of chlorophyll from microalgae for eco-friendly wool dyeing

Microalgae are promising and sustainable sources of diverse valuable compounds, including chlorophyll, a pigment widely used in food, feed, and cosmeceutical applications. Exploring its interesting green hue, recent investigations have delved into alternative industrial applications, such as textile dyeing, aiming to minimize reliance on non-sustainable synthetic dyes. To reduce the use of these environmentally harmful compounds in textile dyeing and establish cost-effective and eco-friendly approaches for chlorophyll extraction, this study investigates the use of chlorophyll extracted from Chlorella vulgaris NIVA CHL-108 for wool dyeing. Aqueous biphasic systems (ABS) composed of ethanol and sodium hydroxide were used for chlorophyll extraction, and the chlorophyll-concentrated phase was used for wool dyeing. This sustainable integrated approach allowed complete chlorophyll recovery and enhanced performance for dyeing mordanted and unmordanted wool. The study achieved a remarkable chlorophyll uptake of 87% after two cycles of dyeing for unmordanted wool, and a recovery of approximately 98% of copper ions for mordanted wool. The study proposes two circular and integrated ABS-based platforms for chlorophyll extraction, concentration, and dyeing, also presenting the challenges impeding their industrial application and proposing strategies to overcome them. This work proves that alcohol/salt ABS-based platforms are simple, circular, and cost-efficient solutions for chlorophyll extraction and utilization in textile dyeing.