Novel Hydroxyapatite Based Nanocomposites as Catalysts or Photocatalysts for Environmental Remediation and Chemical Transformations

Abstract

Hydroxyapatite, HAp is an essential biomaterial and key constituent of bones and hard tissues. Superior mechanical properties, adsorption ability, greater surface energy, and several additional characteristics make HAp nanoparticle as one of the most efficient materials and enable it to employ in diverse fields. Out of different domains, this thesis emphasizes the catalytic as well as photocatalytic applications of various newly designed HAp based nanomaterials. The facile preparation techniques were employed for the fabrication of hydroxyapatite based nanocomposites. The developed materials were utilized as heterogeneous nanocatalysts in the field of environmental remediation and in order to carry out few important organic transformations. In the first work, we reported preparation of ZnFe2O4/HAp-Sn2+, a novel nanocomposite by three-step processes using hydrothermal treatment followed by calcination. The as preparation composite was characterized by Fourier transform infrared spectroscopy (FT-IR), ultraviolet diffused reflectance spectroscopy (UV-DRS), polycrystalline (or power) X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The fabricated nanocomposite exhibited excellent photocatalytic activity in the degradation of two antibiotics namely ofloxacin (OFL) and norfloxacin (NFL) under natural sunlight without use of any oxidizing or reducing agents. Scavenger studies were also carried out to ascertain the active radicals such as superoxide and hydroxyl radical during the photodegradation process.