Browsing by Author "Olkhov, Kostyantin V."

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    PVA-CoFe2O4-Biochar Composites: Structure and Properties
    (Oles Honchar Dnipro National University, Dnipro, 2025) Frolova, Liliya A.; Saltykov, Dmytro Yu.; Kushnerov, Oleksandr I.; Olkhov, Kostyantin V.; Nikitin, Maksim O.; Rodin, Dmytro O.
    ENG: PVA-CoFe2O4-biochar composites were synthesized by a two-stage combined method. The resulting composites were characterized by X-ray diffraction, scanning electron microscopy, UV-visible absorption spectroscopy, vibrational magnetometry, and vector microwave analysis. The results of electron microscopy show that biochar has a block structure with large pores, so this structure can be used in the creation of composites. The magnetic properties depend on the content of cobalt ferrite in the composite. The results of the study of photocatalytic properties showed that the rate of destruction of methylene blue (MB) is 50–98% after 60 min of UV radiation. It was established that the reaction of photocatalytic decomposition of MB obeys pseudo-first-order kinetics. Among these catalysts, biochar showed the highest rate constant of 0.085 min−1, PVA/CoFe2O4-biochar composites – 0.05 min−1. When studying the absorption of electromagnetic radiation in the radar range from 8 GHz to 12 GHz by PVA/CoFe 2O4- biochar composites, it was found that with an increase in the ratio of CoFe2O4-bichar components to 0.67 wt. parts CoFe2O4, the absorption losses of the composite reach –14.15 dB/mm at a frequency of 8 GHz and –12.37 dB at a frequency of 12 GHz.