Paulina Kapuśniak

The series of ceramics with a host composition corresponding to popular 45S5 bioglass doped with manganese ions was prepared using the modified sol-gel technique with a citric acid as a catalyst. The same line of ceramics, for the first time in the case of bioactive glasses or ceramics, was obtained in the procedure applying an addition of a plant extract – aloe vera one -as a surfactant to get more porous material. The structure and properties of the glasses were characterized with SEM, XRD, DSC, Raman and IR spectroscopy. All samples, regardless the Mn ions concentration, are bioactive as it was shown by in vitro immersion in artificial plasma – increase of manganese content improves the bioactivity of the material. The addition of aloe vera gel leads to a significant increase in the surface porosity of the samples; its scale is correlated with content of the aloe vera. Studies reveal that Mn exists in tetrahedral positions coordinating oxygen and reducing concentration of NBO. An addition of aloe vera change this situation lowering cross-linking of the ceramic glassy host. Amount of aloe vera in the presence of Mn dopant plays an important role in speeding the growth of phosphate compounds layers. The phosphorous layer growth during immersion in SBF is both quicker and more intense in the case of material prepared with the plant extract. This study reveal, using Raman 3D mapping, that the HpA is not located only at the surface of the samples but also in the volume and that its volume concentration is bigger than the surface one.

This work reports new physical insights concerning the effect of red lead (Pb₃O₄) addition (10-35 mol %) on the structural, dilatometric, dielectric, and conductivity properties of Sb₂O₃-SiO₂:Pr₂O₃ glasses for potential solid-state electrolyte applications. The melt-quenched glasses were scrutinized via Raman spectroscopy including a temperature-dependent evaluation revealing progressive polymerization of the glass network up to 30 mol % Pb₃O₄, followed by depolymerization at 35 mol %. Harmonizing with the structural evolution, thermal analysis by dilatometry showed that the thermal expansion coefficients/softening temperatures first decreased/increased from 10 to 30 mol % Pb₃O₄ and then increased/decreased for 35 mol % Pb₃O₄. The dielectric properties and ac conductivity were measured over 0.02-1 MHz and 20-240 °C. An increase in Pb₃O₄ from 10 to 30 mol % led to reduced dielectric constant and conductivity, which is attributed to a more compact and polymerized structure that limits ion mobility. Here, conduction is primarily polaronic, supported by mixed-valence Pb²⁺/Pb⁴⁺ and Sb³⁺/Sb⁵⁺ ions. At 35 mol % Pb₃O₄, network depolymerization introduced nonbridging oxygens and structural disorder, enhancing the free volume and ion migration pathways. Consequently, ionic conduction, particularly of Pb²⁺, becomes dominant, significantly boosting the conductivity. Although Pb²⁺ ions are relatively immobile compared to Li⁺ or Na⁺, the insights gained offer a foundational understanding and guide the development of similar glass systems doped with lighter and more mobile alkali ions for practical battery applications.

This study developed a beta-cyclodextrin polymer crosslinked with citric acid (CDCAPol) for removing water contaminants using methylene blue (MB) as a model compound. The polymer, which features free carboxyl groups and cyclodextrin cavities, demonstrated high adsorptive capacity. Under optimal conditions (0.01 g adsorbent, pH 6, and 50 mg/dm³ MB), a removal efficiency of 99.2% was achieved, with a maximum adsorption capacity of 126.58 mg/g as determined by the Langmuir isotherm. Kinetic data fit the best to the pseudo-second-order model, highlighting strong interactions between MB and the polymer. This promising material may find applications in wastewater treatment and environmental protection.