Stabilization and sustained release of rutin dye via eco-friendly Zn/Al-LDH adsorbent: Kinetic, thermodynamic, and antioxidant investigations

Abstract

This study focuses on the stabilization of rutin dye by intercalating it within Zn/Al-LDH (R-Z/A-L) through co-precipitation (CO) and ion exchange (IO) methods. For the IO method, rutin was intercalated onto Z/A-L using a circulator, achieving an optimal intercalation efficiency of 86.37 % and a capacity of 43.18 mg g−1. Comprehensive characterization of the intercalated compounds was performed using XRD, FTIR, FE-SEM, TEM, TGA, DSC, BET, and XPS techniques, confirming efficient intercalation of rutin into LDH. Kinetic analysis indicated that the pseudo-second-order and intraparticle diffusion models best illustrate the intercalation and release mechanisms, respectively. Isotherm data supported the Langmuir model as the most accurate for describing rutin's intercalation behavior. Thermodynamic investigation disclosed the process to be endothermic and spontaneous. Using the CO method, R-Z/A-L was synthesized under optimal conditions with varying rutin concentrations (5 %, 15 %, and 25 %), achieving maximum intercalation efficiencies and capacities up to 98.15 % and 49.07 mg g−1, respectively. Additionally, the antioxidant activity of the intercalated rutin was evaluated, showing that its integration into the adsorbent allowed for prolonged and consistent release. These results confirm the effectiveness of the Z/A-L adsorbent in enhancing stability.