Efficient removal of methyl orange from aqueous solution using mesoporous ZSM-5 zeolite: Synthesis, kinetics and isotherm studies

Abstract

Zeolite are porous material with high surface area and adsorption capacity. It has been employed for the removal of organic contaminants from aqueous system. Here, we report the synthesis of mesoporous ZSM-5 zeolite using a bio template, cellulose. The adsorbent was investigated in detail by different characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption, thermogravimetric analysis (TGA) and 27Al nuclear magnetic resonance (NMR) analysis. The crystalline and MFI nature of the mesoporous ZSM-5 zeolite was confirmed by XRD and FTIR analysis. N2 adsorption/desorption result showed that mesoporous ZSM-5 zeolite has high surface area and pore diameter which was later confirmed through morphological characterization such as SEM and TEM. The adsorption ability of the mesoporous ZSM-5 zeolite was evaluated using methyl orange (MO), an anionic azo dye. The effect of initial dye concentration, adsorbent amount, contact time, temperature and pH on the MO removal process was reviewed. The percentage removal of mesoporous ZSM-5 zeolite is 94.3 % which is much higher than that of the conventional ZSM-5 zeolite (73.2 %). Adsorption isotherm studies were interpreted using two different models i.e., Langmuir and Freundlich model. The result indicates that the adsorption could be well described by Freundlich isotherm model. Meanwhile, kinetic data were best described by pseudo-second-order model. The recyclability test suggest that the synthesized adsorbent has superior regeneration capacity and is stable even after eight adsorption-desorption cycle. Thus, our results show that mesoporous ZSM-5 zeolite is a promising competitor for the removal of dye from aqueous medium.