USE OF IR SPECTROSCOPY FOR STUDY OF STRUCTURE OF LOW-MODULUS ZEOLITES

Abstract

A brief description of the low-modulus zeolites structure is given. Constructions of "building" units were discussed. Namely, the structures of TO4 tetrahedron, a simple four-membered ring (S4R), a double four-membered ring (D4R), a simple six-membered ring (S6R), a double six-membered ring (D6R), α-cell and β-cell were described in details. IR spectroscopy and X-ray diffraction were used to study the structure of zeolites. The types of interatomic bonds vibrations (stretching and deformation) were represented. The reasons of the absorption bands appearance in the IR spectra were described. The literature data for IR spectroscopy studies of zeolites structure were summarized. The ranges of localization of absorption bands on IR spectra for aluminosilicate frameworks as well as for OH groups and molecular water were identified. The absorption bands which correspond to the stretching and deformation vibrations of TO4, S4R, D4R, S6R and D6R were revealed. The examples of X-ray patterns and infrared spectra for the LTA and SOD samples were given. These samples were prepared from mixtures of metakaolin and sodium hydroxide with an atomic ratio Si: Al equals to 1: 1 and 1: 1⅓ using mechanochemical activation or ultrasonic treatment and calcined at various temperatures. It was shown that in the IR spectrum of SOD, absorption bands of TO4 and S4R were distinctly identified. The effect of mechanochemical and ultrasonic treatment of raw ingredients on the intensity of absorption bands was established. Also, the change in the IR spectrum of the LTA zeolite after calcination was demonstrated. It was found that with increasing calcination temperature, the intensity of the absorption bands of S4R, D4R decreases, which indicates the destruction of the zeolite framework.For citation:Kul’pina Yu.N., Prokof’ev V.Yu., Gordina N.E., Khmylova O.E., Petukhova N.V., Gazakhova S.I. Use of ir spectroscopy for study of structure of low-modulus zeolites. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 44-50.