Eco-friendly dyeing and functional finishing of silk fabric using a natural dye from Arjuna fruit enhanced by metallic salts

The textile industry is a major contributor to global water pollution and carbon emissions and is facing increasing pressure to transition away from synthetic dyes toward sustainable, non-toxic alternatives that produce persistent toxins, such as carcinogenic aromatic amines. This study investigates the potential of Arjuna fruit extract as a natural dye for silk fabric by optimizing the extraction and dyeing processes and evaluating the resulting multifunctional properties. The dye, which is rich in polyphenols and flavonoids, was extracted under optimal conditions (90°C, 75 min, pH 7) and characterized using UV-Vis, FTIR, and LC-MS. Silk fabric was pre-mordanted with Al3+, Fe2+, Cu2+, and K+. The study demonstrated that iron (II) mordanting enhances the multifunctional potential of the Arjuna fruit dye on silk, simultaneously achieving high color intensity ( K/S :15.656), UV protection (UPF: 278.7), color fastness (grades: 4-5), enhanced moisture regains (14.88%), and antibacterial efficacy (98.84% inhibition), surpassing existing natural dye systems and rivaling synthetic alternatives. Structural analyses (FTIR, XRD, SEM-EDX) confirmed the stability of silk fibroin and effective dye-metal coordination. Environmental toxicity assessments revealed low aquatic toxicity (96-hour LC50 = 108.79 mg/L for zebrafish), underscoring its favorable environmental profile but still highlighting the importance of responsible dye disposal practices, even for low-toxicity substances. This paper demonstrates that Arjuna fruit dyes with Fe2+ mordants provide a sustainable, high-performance alternative to synthetic dyes. They contribute to efforts to reduce the textile industry's environmental impact while maintaining high-performance functionality and environmental responsibility.