Electrical and dielectric properties of MnF2–ZnF2–NaPO3 glasses

Direct electrical conductivity and dependencies of complex electrical modulus vs. temperature and frequency have been measured on glasses from the MnF₂–ZnF₂–NaPO₃ system. These glasses are sensitive to atmospheric humidity and as a consequence, the electrical conductivity increases up to temperature of 50 °C. A hydrated layer is created by the effect of water and leads to the significant increase of the electrical conductivity in the case of 0MnF₂–20ZnF₂–80NaPO₃ glass. This behavior is governed by Arrhenius relation where the values of activation energy are increasing and values of the electrical conductivity are decreasing with the amount of MnF₂. Dielectric measurements show that a heterogeneous phase is formed in the bulk of glasses. This may be seen when plotting complex electrical modulus in the complex plane. The records made by the light microscope confirmed the occurrence of the other phase in the bulk of glasses.     

Fluorophosphate glasses containing manganese

New fluorophosphate glasses based on MnF₂, NaPO₃ and MF_n (M=Zn²⁺, Sr²⁺, Mg²⁺, Ba²⁺, Li⁺, Na⁺ and K⁺) have been synthesised and characterized. Large vitreous areas were observed. Samples of 4 mm in thickness have been obtained. These glasses are easy to prepare and stable in ambient air. Depending on the composition and the nature of the M cation, glass transition temperature, T_g, lies between 230 and 314 °C, crystallisation temperature, T_x is between 320 and 475 °C. These glasses are pink coloured, and infrared transmission extends up to 4.5 μm with extrinsic OH⁻ absorption band at 3200 cm⁻¹ and other bands around 2200 and 1600 cm⁻¹ that relate to PO₄ tetrahedron vibration. Other physical properties including density, microhardness, Young modulus, thermal expansion and refractive index were investigated and correlated to composition.     

Tetracycline Adsorption onto Agave Americana Activated Carbon: Studies of Physicochemical Parameters and Porous Structure

Theoretical and Experimental Chemistry - The isotherms of adsorption of tetracycline on activated carbon obtained from Agave Americana fibers were analyzed using the method of statistical physics....