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Abstract The increasing emphasis on environmental sustainability and the demand for eco‐friendly practices have led to a surge in interest in natural products, particularly natural dyes, across industries, including textiles. Curcumin, extracted from the turmeric plant, has gained widespread application not only for its vibrant colour characteristics but also for numerous therapeutic properties, serving as an antioxidant, anti‐inflammatory agent, and promoting wound‐healing effects. This study aims to understand the physical and chemical phenomena associated with the adsorption and desorption of turmeric extract and its active principles on cotton and polyamide fibres through mathematical models, with the goal of expanding textile applications. Dyeing experiments revealed adsorption equilibrium times of less than 25 min for both fibres, with the pseudo‐second‐order model providing the best fit for dyeing kinetics, suggesting control through the chemisorption process. The Freundlich model better suited cotton adsorption isotherms ( R 2 = 0.778), while the Langmuir model fit well for polyamide ( R 2 = 0.981). Thermodynamic parameters indicated non‐spontaneous interactions between curcumin and cotton, with an endothermic process, and an exothermic and spontaneous process for polyamide. Friction and water tests indicated greater colour resistance for polyamide, with grades exceeding 4. Desorption tests in 100% ethanol solution showed a total release of only 0.88% and 0.97% for polyamide and cotton, respectively, sustained for 12 h, fitting the Higuchi mathematical model, indicating a purely diffusive release process. These results demonstrate the potential of curcumin dye for achieving high dye exhaustion percentages in natural and synthetic fabrics and sustained release properties.
Schmidt et al. (Wed,) studied this question.