Review on Current Research of Fabrication, Properties and Applications in Zeolite

Zeolites consisted of aluminum ion and silicon ion, surrounded by oxygen anions. These materials could be categorized into natural zeolite and synthetic zeolite, respectively. The uses of zeolites include ion exchanger, agricultural, catalysis, adsorption process and water purification. Formation of zeolite could be carried out using solvothermal, ionothermal synthesis method, microwave-assisted method, and hydrothermal. The quality of the obtained zeolites depends on experimental conditions such as pH, adsorbent dosage, contact time, composition of precursors, and temperature. Characterization of zeolite has been studied using x-ray diffraction technique, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray fluorescence spectroscopy, and scanning electron microscopy technique. Surface properties, pore size distribution, thermal stability, acidic/alkaline behaviors, mobile cation, and pore size have been reported based on the literature review. In this work, the adsorption of heavy metal, carbon dioxide gas, dye and phenolic compounds onto natural and modified zeolite has been investigated. Sometimes, cobalt, copper, iron, and sodium were used to modify the zeolite surface. The adsorption data was investigated using Langmuir, Temkin, Freundlich isotherm models. Kinetic study was studied using pseudo first-order and pseudo second-order models. The adsorption process was spontaneous (negative Gibbs free energy), exothermic (negative enthalpy) and randomness of the system decreases (negative entropy) based on the thermodynamic parameters.