Structural, optical, thermal, and photocatalytic properties of electrospun calcium carbonate fibers synthesized from polyvinyl alcohol-calcium acetate precursors

This study examines the thermal, structural, optical, and morphological properties of calcium carbonate (CaCO3) fibers produced by a novel method of calcination of electrospun polyvinyl alcohol (PVA) fibers reinforced with calcium acetate monohydrate (CaAc). TGA and DSC show improved enhanced thermal stability of PVA-CaAc fibers compared to pure PVA. Structural analysis by DRX confirms the formation of calcite as the primary crystalline phase. SEM images show a significant reduction in the diameter of the calcined fibers and the development of a porous morphology. Reflection-transmission spectrophotometry shows a band gap of 3.45 eV for the CaCO3 fibers with possible contributions from carbon traces, which may further reduce the bandgap and, therefore, prove to be suitable photocatalysts for visible-light-driven applications. For this reason, the photo- catalytic activity of the calcined fibers was analyzed under UV and solar irradiation for the photodegradation of methylene blue in aqueous solutions. These results highlight the improved thermal and structural properties of the CaCO3 fibers, which make them promising candidates for advanced material applications, especially in the biomedical and environmental fields.