ISSN 2738-0971 | eISSN 2738-1013

Milena Rosić

Institute of Nuclear Sciences “Vinča”, National Institute of the Republic of Serbia, University of Belgrade, Serbia

Articles

Open Access Original Scientific Paper

MINERALOGICAL COMPOSITION AND PROPERTIES OF PELOID FROM DUČEVAC, SERBIA, TRADITIONALLY APPLIED TO HAIR TREATMENT

This study analyzes mineralogical composition and properties of two samples sourced from Dučevac, Serbia, which are traditionally used in hair treatment. This investigation provides the first systematic, multidisciplinary characterization of the specified material, comparing the samples with respect to their mineralogical phases, chemistry, and physicochemical properties. Notably, sample 1.1 is primarily calcite, with a smaller amount of clay minerals (illite, kaolinite, and smectite). In contrast, sample 1.2 showcases a blend of illite and quartz, with small amounts of other clay minerals (smectite, kaolinite, chlorite) and plagioclase. Sample 1.1 has higher amounts of CaO (9.83 wt.%) and Na2O (2.97 wt.%) than sample 1.2; in return, sample 1.2 has higher amounts of Fe2O3 (4.25 wt.%) and MgO (4.61 wt.%). In terms of pH, both samples are moderately acidic, with CEC values ranging from 8 to 9 meq/100g, and SSA measurements between 66 and 75 m²/100g. The color also reflects distinct variations, with sample 1.1 registering at 583 nm and sample 1.2 at 573 nm. All analytical values align with reference peloids found in literature, enhancing our understanding of the samples' characteristics and origins. This highlights the material's geological significance and the importance of preserving traditional practices as part of the region's geoheritage.

Open Access Original Scientific Paper

STRUCTURAL AND ELECTROCHEMICAL PROPERTIES OF SYNTHESIZED NANOSTRUCTURED Ca0.9Er0.1MnO3 BY HYDRAZINE NITRITE PROCEDURE

Synthesis, structural, and electrochemical properties of nanostructured powders Ca0.9Er0.1MnO3 with perovskite-type crystal were studied. Nanopowders were prepared by the combustion method using the hydrazine nitrite procedure (HNP), which involves mixing metal nitrate salts (Ca, Mn, Er) in a stoichiometric ratio and varying the quantity of added hydrazine. In this synthetic procedure, the aim is to adjust the amount of hydrazine in order to control the combustion of the reactions, obtain the required amount of fuel energy, but also the amount that will complex the reactants in the mixture. The powders obtained by hydrazine nitrate synthesis were then calcined for 15 minutes at temperatures of 800, 900, and 1000 °C. Characterization of the synthesized and calcined samples was performed using advanced techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and electrochemical measurements. The results clearly indicate that the amount of hydrazine added is crucial in preparing the Ca0.9Er0.1MnO3 sample. This highlights the importance of precise hydrazine dosage in optimizing the synthesis process to enhance the material's properties. Further, the electrochemical properties of the obtained perovskite nanopowders were investigated by cyclic voltammetry (CV) and electrochemical spectroscopic impedance (EIS) on perovskite-modified carbon paste electrodes. Electrochemical measurements showed improved electrochemical properties of perovskite-modified carbon paste electrodes compared to bare carbon paste electrode (CPE). The electrode modified with the material synthesized with the smallest amount of hydrazine presented the best results.