Effect of nanocrystalline zeolite Na-Y on meta-xylene separation

The adsorption process for separation of meta-xylene from xylene mixture on binder-free nanocrystalline and microcrystalline zeolite Y modified with sodium cation was investigated in the liquid phase. X-ray diffraction, scanning electron microscopy (SEM), nitrogen adsorption and in situ Fourier transform infrared (FTIR) spectroscopy were also performed to study the type of adsorbed species and their thermal stabilities. The adsorption process was carried out at temperature of 110–160 °C and pressure of 6–10 atm. The effect of zeolite water content on the adsorption process was investigated. The influence of SiO2/Al2O3 ratio on selectivity factor of meta-xylene to other C8 aromatic isomers was also studied. The adsorption isotherms for each isomer of C8 aromatics and desorbents illustrated the typical Langmuir type. It was observed that selectivity of meta-xylene was increased with decreasing the particle size of crystalline zeolite Y from micro to nano-scale. The best selectivity factor of meta-xylene to para-xylene, ortho-xylene and ethylbenzene on nanocrystalline zeolite Na-Y reached to be 2.90, 3.16 and 6.88, respectively, and compared with those obtained with microcrystalline zeolite Na-Y. Desorbents like toluene and indan were also tested to optimize the process.

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► Separation of m-xylene on binder-free nano and microcrystalline Na-Y.
► Influence of SiO2/Al2O3 ratio in selectivity factor of meta-xylene to other C8 isomers.
► Optimization of process with desorbents like toluene and indan.
► Increasing of m-xylene selectivity with decreasing of particle size to nano.
► Maximum selectivity of MX/PX, MX/OX and MX/EB acquired 2.545, 2.243 and 5.958.