Kinetic and Thermodynamic Analysis of Acid Dye Adsorption on UV/Ozone-Treated Wool Fabric

In the present study, the synergistic effects of wool exposure to ultraviolet light and ozone gas on the kinetics and thermodynamics of dyeing using a leveling and a milling acid dye have been examined. The results showed that a 20-min exposure to ultraviolet/ozone improved the wettability of wool and reduced its felting shrinkage by approximately 100% and 74.13%, respectively. The solubility examination of the wool fabric in alkali was also conducted, which showed no significant alteration in the chemical properties of the treated samples. Following the wool treatment, Young's modulus value and consequently the wool's elasticity were slightly reduced. However, the wool's tensile strength and elongation percentage improved by 53.6% and 39.5%, respectively. Due to the breakdown of the surface diffusion barrier of the wool fiber, the dyeing rate of both leveling and milling acid dyes increased by about two times when compared to the untreated wool. Similar results were obtained when the milling acid dye was dyed at low temperatures. During the initial first 5 min of the dyeing process, the dye exhaustion of the treated wool fiber was assessed to be 38.6%, whereas it was 15.2% for the untreated fiber. Thermodynamic analysis of the samples dyed with the acid leveling dyes indicated that while the standard affinity remained unchanged, there was a reduction in the heat and entropy of dyeing for the treated wool. These observations suggest that the adsorption propensity of the acid dye to the wool fiber was not affected by the ultraviolet/ozone treatment.