Adsorption of xylene isomers using Ba-faujasite type zeolite: Equilibrium and kinetics study

In the present study, liquid phase isotherm adsorption of single component of para xylene, meta xylene, ortho xylene, and ethylbenzene onto a commercial molecular sieve adsorbent (SPX3000-fine) at three different temperatures of 25, 50 and 75 °C had been investigated. It was found that para xylene was the most adsorbed component followed by ethylbenzene, meta xylene and ortho xylene, showing the strong adsorption of para xylene by the understudy adsorbent. All kinds of used xylene isomers brought out decreased adsorption loading on SPX3000-fine zeolite with increasing the temperature in the range of 25-75 °C. Aims to study the description of equilibrium adsorption data, Langmuir, Freundlich, and Tempkin isotherms were applied, which superiority of Langmuir model to describing equilibrium isotherm data with the highest R2 values was obtained. The kinetic study was performed by applying three kinetic models of pseudo-first-order, pseudo-second-order and intraparticle diffusion. According to the obtained results, the pseudo-second-order model is the best representative model to describe the kinetic adsorption data. Also, thermodynamic study revealed that due to the negative values of adsorption heat and Gibbs free energy changes, the adsorption of para xylene in the binary system proceeded an exothermic spontaneous process.