Improved catalytic and biological activities of chitosan and polyvinylpyrrolidone incorporated barium ferrite with density functional theory and molecular docking studies

Objectives Rapid industrial development, pollution and discharge of untreated waste into fresh water causing serious health issues. Herein, catalytic and antibacterial activities of synthesized nanostructures (NSs) were evaluated against target contaminants Rhodamine B (RhB) and multiple drug-resistant Escherichia coli (MDR E. coli ), respectively, with a computational molecular docking study. Methods A facile co-precipitation route was employed to synthesize BaFe₂O₄ containing 3 and 6 wt.% chitosan with a fixed amount of polyvinylpyrrolidone (PVP) at low temperature. Several techniques were adopted to investigate phase formation, surface morphology, optical properties, and functional groups of prepared NSs. Results Absorption spectra revealed a gradually increase in absorption towards longer wavelength with addition of PVP and CS, leading to a decrease in bandgap energy (Eg) from 2.25 to 2.19 eV. Orthorhombic phase of BaFe₂O₄ corroborated by XRD analysis, and with inclusion of dopants crystallite size was increased. Multiple morphologies (nanoparticles and nanorods) were confirmed by TEM analysis. Consequently, 6 wt.% CS/PVP-BaFe₂O₄ exhibited considerable dye degradation of 87.55% in neutral medium as well as significant bactericidal activity against MDR E. coli with inhibition zone 9.45±0.03 mm. Furthermore, computational molecular docking studies indicated that NSs, including CS/PVP-BaFe₂O₄, possess capability to inhibit the DNA gyrase enzyme in E. coli . Conclusion This study demonstrates substantial potential of CS/PVP-BaFe₂O₄ for dye degradation and bactericidal applications.