Synthesis of Faujasite-Na-type zeolite from partial de-aluminated metakaolin for removal of methylene blue from contaminated water

Abstract

In this study, Faujasite Na-zeolite was synthesized using a hydrothermal method involving partial de-alumination metakaolin (PDK), sodium hydroxide, and aluminum sulfate. PDK is the solid residue generated during the aluminum sulfate manufacturing process. The synthesized Faujasite-Na-zeolite was evaluated for its effectiveness in removing methylene blue (MB), a positively charged dye, from contaminated water. The prepared zeolite was characterized using several analytical techniques, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM micrographs revealed that the Faujasite possessed a high surface area and spherical crystals of diameters ≤ 1 micron. The efficiency of the synthesized Faujasite Na-zeolite in eliminating the methylene blue (MB) dye from tainted water was assessed. Various factors were tested including; the amount of zeolite added, the initial concentration of the dye, the removal temperature, the solution pH, and the contact period. The results indicated that the adsorption capacity of methylene blue wear (195.6 mg/g) was attained under the following conditions: an initial dye concentration of 0.1 g/L, a temperature of 55 °C, a contact period of 4 h, and a pH of 10. The adsorption data were analyzed using many isothermal models, including the Freundlich, Langmuir, and Temkin models. The findings suggested that the adsorption process is best fitted by the Freundlich isotherm model. Additionally, the kinetics of the adsorption process were investigated by applying pseudo 1st and pseudo 2nd models. The results indicated that a pseudo 1st order model effectively describes the adsorption behavior of the methylene blue dye using the Faujasite Na type zeolite.