Preparation and development of FeS2 Quantum Dots on SiO2 nanostructures immobilized in biopolymers and synthetic polymers as nanoparticles and nanofibers catalyst for antibiotic degradation

The FeS2 Quantum Dots (QDs) decorated SiO2 nanostructure were prepared by hydrothermal synthesis method. Chitosan and polypyrrole as polymers were used for the immobilization process. The characteristic structure of prepared samples was analyzed using several techniques such as X-ray diffraction, scanning and transmittance electron microscopy, photoluminescence and UV-vis spectroscopy. The mean crystallite sizes of FeS2 QDs/SiO2 nanocomposites, FeS2 QDs/SiO2-chitosan nanocomposites and FeS2 QDs/SiO2-polypyrrole nanohybrids are 56.12, 76.38, and 83.24 nm, respectively. The band gap energy of FeS2 QDs/SiO2 nanocomposites, FeS2 QDs/SiO2-chitosan nanocomposites and FeS2 QDs/SiO2-polypyrrole nanohybrids were found out to be 3.0, 2.8, and 2.7 eV, respectively. The photocatalysis properties were investigated by degradation of ampicillin under UV light illumination. The effect of experimental variables, such as, pH and time, on photo-degradation efficiency was studied. The results show that the three prepared samples nanopowders under UV light was in pH 3 at 60 min. As it could be seen that the amount of ampicillin degradation was increased with the loading of FeS2 QDs on SiO2 and FeS2 QDs/SiO2 on chitosan nanoparticles and polypyrrole nanofiber. The antibacterial experiment was investigated under visible light illumination and the FeS2 QDs/SiO2-chitosan nanocomposites and FeS2 QDs/SiO2-polypyrrole nanohybrids demonstrate good antibacterial compared to FeS2 QDs/SiO2 nanocomposites.