THE STUDY OF CLINOPTILOLITE MODIFIED WITH3d METALS HALIDES BY IR AND DIFFUSE REFLECTANCE SPECTROSCOPY

• Main Authors: T. L. Rakitskaya, A.S. Truba, L. A. Raskola, I. V. Stoyanova
• Format: Article
• Language: English
• Published: Odessa I. I. Mechnikov National University 2015-11-01
• Series: Vìsnik Odesʹkogo Nacìonalʹnogo Unìversitetu: Hìmìâ
• Subjects: клиноптилоліт, галогеніди 3d-металів, ІЧ-спектр, дифузне відбиття
• Online Access: http://heraldchem.onu.edu.ua/article/view/50624

The results of investigation of natural clinoptilolite (N-CLI) and that modified with 3d metal halides (MeCl2/N-CLI, where Me are Cu, Co, and Mn) by IR and diffuse reflectance spectroscopy are summarized. A band at 3437 cm-1 assigned to stretching vibrations of hydroxyl groups (nOH) is found in the IR spectrum of the N-CLI sample. A location of the band was practically the same as for all above MeCl2/N-CLI samples. A band of middle intensity at 1638 cm-1 in the range of deformation vibrations of zeolite water observed in the IR spectrum of N-CLI slightly displays to lower frequencies in the case of the modified samples. An intensive wide band of a complex shape in the range from 1250 to 980 cm-1 assigned to Si–O–Si and Si–O–Al vibrations appears in IR spectra of all samples. A doublet band of middle intensity at 797 and 778 cm-1 is assigned to external symmetric stretching T-O vibrations and a band at 606 cm-1-to vibrations of a double ring. A location of the above bands is the same for all listed samples but their intensity is higher for MnCl2/N-CLI and CoCl2/N-CLI samples. After the reaction with ozone, significant changes in the IR spectra are observed only for MnCl2/N-CLI. They are due to MnO2 formation on the clinoptilolite surface resulting in a high frequency displacement of some bands. Based on UV-vi spectroscopy results, it is reasonable to make conclusions about the coordination and valence state of a central atom in the MeCl2/N-CLI samples under study. A location of charge transfer bands for these samples only slightly differs from that for N-CLI however the intensity of such bands increases for the MeCl2/N-CLI samples. The UV-vis spectrum of MnCl2/N-CLI changes after the reaction with ozone: the appearance of new bands of  charge transfer at 363 and 354 nm and also the two-fold increase in intensity of a charge transfer band at 272 nm in comparison with those of N-CLI and MnCl2/N-CLI are the evidence of change in both the oxidation degree and the ligand environment of the central atom. Absorbance bands due to d-d transfers which are absent in the visible region of N-CLI and Mn(II)/N-CLI spectra are observed in those of Cu(II)/N-CLI and Co(II)/N-CLI. Cu(II) has been found to be in the distorted octahedral oxygen or mixed oxygen-chloride environment whereas the environment of Co(II) is pseudotetrahedral.