Quinoline adsorption from organic phase on X‐type zeolites: Experimental and DFT study

Abstract

In this study, the adsorptive denitrogenation from organic phase over zeolite adsorbents was studied by batch adsorption experiments. An appropriate amount of quinoline as a nitrogen‐containing compound was dissolved in iso‐octane and utilized as feed. The physicochemical properties of the adsorbents were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 physical adsorption, and energy‐dispersive X‐ray spectroscopy (EDS). The NiX zeolites showed a higher ion‐exchange degree and lower crystallinity. The maximum adsorption capacity and kinetic constant of CrX zeolite as compared to NaX zeolite were improved by 10% and 70%, respectively. Based on the kinetic and thermodynamic studies, it was found that CrX zeolite is a very efficient adsorbent for the removal of quinoline from iso‐octane. Also, the underlying mechanism for quinoline adsorption on parent X and ion‐exchanged zeolite was investigated by the density functional theory (DFT) method. DFT results indicated that among all the cations in zeolites, Cr3+ shows the strongest interaction with nitrogen in the quinoline molecule. The used parent NaX and ion‐exchanged zeolite can also be regenerated by ethanol elution and heating at 573 K, and 65% to 90% of the adsorption capacity of the zeolites was regenerated by these methods.