Sustainable Coloration and Functionalization of Cotton Fabric Dyed with Bombax ceiba Flower Extract and Bio-Mordants

This research examines the dyeing of cotton fabric using a natural dye, extracted from Bombax ceiba flowers, aiming primarily to carry out the entire dyeing process without conventional inorganic mordants. The dye was extracted in an alkaline medium, while three agricultural waste-derived bio-mordants, eucalyptus bark, onion peel, and aloe vera peel, were used to enhance the functional textile properties. These natural tannin-based mordants and phenolic mordants enabled the uptake of dye in an efficient way without releasing toxic chemicals, unlike the conventional metallic mordants. Various concentrations of each mordant were used in the preparation of dyed cotton samples, while NaCl was added in different concentrations to boost the exhaustion process. Among the three types of mordants tested, eucalyptus bark provided the best results, giving samples with a high washing fastness (rating of 4–5) and good rubbing fastness (rating of 3–4 on the gray scale). The progressively darker peach colors were achieved by adding more concentration of the eucalyptus mordant. Onion peel-mordanted samples ranged in color from dark yellow to orange, whereas aloe vera led to a unique peach color. Given the inherent antibacterial and antioxidant properties of Bombax ceiba, the dyed fabrics also possessed functional bioactive characteristics, which were further improved by the addition of bio-mordants. Furthermore, the ultraviolet protection factor (UPF) of the dyed fabric was approximately threefold higher than that of the undyed fabric, indicating a significant enhancement in UV-shielding performance after dyeing. This study conclusively demonstrates that bio-mordants serve as eco-friendly alternatives to chemical mordants, offering excellent colorfastness, diverse aesthetic possibilities, and functional properties, thereby supporting sustainable textile coloration practices.