Thermodynamic And Kinetic Study Of The Adsorption Of Congo Red Dye From Its Aqueous Solutions On The Surface Of Nano-Activated Charcoal Prepared From Myrtle Leaves

The adsorption properties of Congo Red (C.R.) dye from its aqueous solutions were studied using ultraviolet-visible spectroscopy by measuring the absorbance to monitor the adsorption efficiency. Then, the factors affecting the adsorption efficiency were studied, represented by studying the effect of the equilibrium time of the dye under study, the weight of the adsorbent surface, and the temperature, where the Study of the kinetic behaviour of dye adsorption on the adsorbent surface at a fixed concentration of the adsorbent 10-5M)×5)and an appropriate weight (0.05 g) at the equilibrium time (25 minutes) for Congo Red dye. The results showed that the percentage of dye adsorption efficiency (C.R.) increases with increasing equilibrium time. The thermodynamic functions for the adsorption process were calculated over a range of different temperatures (Cᵒ (15, 25, 35, 45, 55) for the dye under study, and the compression free energy, enthalpy change, and entropy were practically obtained. The results showed that ΔGᵒ is negative for all systems, which means that the process Adsorption of the dye onto the surface of activated charcoal occurs spontaneously, and negative (∆Hᵒ) values indicate that the adsorption process is heat-intensive and prefers the direction of physical adsorption because it is less than 40 KJ/mol. Adsorption isotherms for the dye under study were applied to the adsorbent surface of myrtle leaves activated using isotherms. Langmuir, Freundlich, and Temkin. The results showed that the Freundlich, Lankmeyer, and Temkin isotherms are suitable for representing the adsorption process, with good correlation coefficients. The studied adsorption system was followed kinetically using the kinetic equations, which are: the pseudo-first-order equation and the pseudo-second-order equation. The results showed that the adsorption process is subject to the second-order equation. False according to the correlation coefficient (R2), which gave the best value compared to the first-order equation.