Optical and epr spectroscopy of natural zeolite modified by microwave-assisted method

Natural zeolite samples from the Nor-Kokhb deposit (Armenia), as well as chemically and thermally modified by the microwave method, were studied in comparison with the traditional one. It is shown that the microwave treatment process proceeds 3 times faster than the traditional one. XRD analysis shows that the main mineral in the studied zeolite samples is clinoptilolite. According to the results of optical and EPR spectroscopy, the presence of Fe³⁺ ions in the framework and extra framework positions of the zeolite was revealed. The study of the diffuse reflectance spectra made it possible to conclude that the zeolite is a wide-gap material with a band gap of 4.14 eV