Abstract

Physicochemical attributes and solubilization of reactive dyes in single and mixed micellar media are elaborated in this study. The enhanced entrapment of reactive dyes was observed in the mixed-micellar media of cationic surfactant, cetyltrimethylammonium bromide (CTAB) and nonionic surfactant, (Triton X-100) as compared to single-micellar media of CTAB. Two reactive dyes viz. Reactive Black 5 (RB) and Reactive Yellow 145 (RY) were used for this interactional study. The solubilization in terms of partition constant (K_c), partition coefficient (K_x), binding constant (K_b), Gibbs free energies (ΔG_p and ΔG_b) and the approximate location of dye molecules in the micelles, was assessed by UV–Vis spectroscopy. From the experimental findings, it was concluded that the mixing of CTAB with a nonionic surfactant is recommended to achieve a superior degree of entrapment of dye molecules as compared to the single surfactant. The RB, the magnitude of K_x was 520 × 10⁵ in CTAB media, whereas this value lowered to 195 × 10⁵ in the mixed-micellar system (MMS). A similar trend was observed in RY and the single and MMSs showed respective K_x values of 207 × 10⁵ and 19.7 × 10⁵. The higher negative magnitudes in the case of single surfactant indicated greater partitioning of dyes while the mixed system caused deep penetration of dyes. The lower values of Gibb’s free energies of partition and binding were indicative of greater penetration of dyes within the micelles.

摘要

本研究详细阐述了活性染料在单一和混合胶束介质中的物理化学特性和增溶作用。与 CTAB 的单胶束介质相比，在阳离子表面活性剂十六烷基三甲基溴化铵 (CTAB) 和非离子表面活性剂 (Triton X-100) 的混合胶束介质中观察到活性染料的截留增强。两种活性染料，即。反应性黑 5 (RB) 和反应性黄 145 (RY) 用于该交互研究。以分配常数 ( K _c )、分配系数 ( K _x )、结合常数 ( K _b )、吉布斯自由能( Δ G _p和 Δ G _{b ) 表示的溶解度}）和胶束中染料分子的大致位置，通过紫外-可见光谱进行评估。从实验结果得出结论，与单一表面活性剂相比，建议将 CTAB 与非离子表面活性剂混合以实现更好的染料分子截留程度。RB，K _x的大小在 CTAB 介质中为 520 × 10 ⁵ ，而在混合胶束系统 (MMS) 中该值降低到 195 × 10 ^{5 。}在 RY 中也观察到了类似的趋势，单个和 MMS 的K _x值分别为 207 × 10 ⁵和 19.7 × 10 ⁵. 在单一表面活性剂的情况下较高的负值表示染料的更大分配，而混合体系导致染料的深度渗透。Gibb 的分配和结合自由能值较低表明染料在胶束内的渗透性较大。