THERMODYNAMIC AND KINETIC STUDY OF ADSORPTION OF THE AZO DYE FROM AQUEOUS SOLUTION ON THE SURFACE OF IRAQI FLINTMONTAHA K. SULTAN AND SUHAD S. MOHAMMED
This research focused on studying the ability of Iraqi Flint to remove methyl orange of aqueous solutions of different concentrations of adsorbent and it was studied by changing the contact time, pH, temperature, and amount of adsorbent. Using 0.1 g of Iraqi Flint, the maximum adsorption of dye (>37%) was achieved in aqueous solutions. The experimental data have been examined using Langmuir, Freundlich and Temkin isotherms models, the adsorption pattern on Iraqi flint appears to follow the Freundlich and Temkin isotherms, according to the outcomes obtained at (303, 313, and 323) K. In this work, four kinetic models (the pseudo first-order, the second-order, Elovich, and Intraparticle Diffusion) were used, to fit the experimental data. The adsorption kinetic process was found to follow a pseudo-second-order model. The slope and intercept of the linear plots of Ln Keq versus 1/T were used to compute thermodynamic parameters such as ïGo, ïSo, and ïHo it showed that adsorption of MO- was spontaneous, exothermic and randomness at a different temperature.