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The adsorption properties of Ukrainian Transcarpathian clinoptilolite in aqueous copper(H) solutions under dynamic conditions have been investigated. Under optimum conditions (pH of Cu2+ solution = 7.1; adsorbent thermally modified at 120-170°C for 2.5 h; flow rate of Cu2+ solution through adsorbent = 3 ml/min), the adsorption capacity of the clinoptilolite towards copper amounted to 725 ng/g. The conditions for the desorption of copper(II) from clinoptilolite have been studied. Of the desorbents tested, the best were HNO3 (1:1) and HNO3 (1:2) solutions. Their effectiveness in extracting copper(II) ions under the desorption conditions employed amounted to 100%.

The adsorption properties of Ukrainian Transcarpathian mordenite in aqueous copper(II) solutions under dynamic conditions have been investigated. Under optimum conditions (pH of Cu2+ solution = 6.5; adsorbent thermallly modified over 2.5 h at 150°C; rate of passage of Cu2+ solution through adsorbent = 3 ml/min) the adsorption capacity of the mordenite towards copper amounted to 1020 μg/g. Copper is effectively desorbed by an aqueous solution of HNO3 (1:2). Under optimum desorption conditions the effective extraction of copper was 99.8%.

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In this study, we carried out a detailed investigation of the photoluminescence of Mn4+ in Ga2O3–Al2O3 solid solutions as a function of the chemical composition, temperature, and hydrostatic pressure. For this purpose, a series of (Al1–x Ga x )2O3:Mn4+,Mg phosphors (x = 0, ..., 0.1.0) were synthesized and characterized for the first time. A detailed crystal structure analysis of the obtained materials was done by the powder X-ray diffraction technique. The results of the crystal structure and luminescence studies evidence the transformation of the ambient-pressure-synthesized material from the rhombohedral (α-type) to monoclinic (β-type) phase as the Ga content exceeds 15%. Spectroscopic features of the Mn4+ deep-red emission, including the temperature-dependent emission efficiency and decay time, as well as the possibility of their tuning through chemical pressure in each of these two phases were examined. Additionally, it has been shown that the application of hydrostatic pressure of ≥19 GPa allows one to obtain a corundum-like α-Ga2O3:Mn4+ phase. The luminescence properties of this material were compared with β-Ga2O3:Mn4+, which is normally synthesized at ambient pressure. Finally, we evaluated the possibility of application of the studied phosphor materials for low-temperature luminescence thermometry.