Banca de QUALIFICAÇÃO: TANARA CAROLINE NUNES NICÁCIO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : TANARA CAROLINE NUNES NICÁCIO
DATE: 05/05/2023
TIME: 14:00
LOCAL: Sala virtual (videoconferência)
TITLE:

Effect of zinc and nickel doping on photocatalytic and antimicrobial properties of hydroxyapatite

KEY WORDS:

hydroxyapatite, doping, zinc, nickel, photocatalysis, antimicrobial activity.

PAGES: 89
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Studies have been developed on the incorporation of metals in hydroxyapatite to improve antimicrobial and photocatalytic properties, since when performing surgical procedures, HAp often has some limitations, such as the difficulty of in situ microorganisms, causing failure in the bone restoration process due to bacterial infection problems. In this work, HAp nanoparticles were synthesized by microwave-assisted hydrothermal method and doped and co-doped with zinc and nickel using different concentrations of dopant ions. The crystalline structures of the pure and doped samples, chemical composition and their morphologies were characterized by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy by field emission (SEM -FEG), respectively. Optical properties were estimated from UV-Visible spectroscopy. The hydrothermal method used in this work proved to be efficient for obtaining HAp nanoparticles. The XRD patterns together with the structural refinement, showed the HAp formation for all samples, which corresponds to the hexagonal crystalline structure. There was no secondary phase formation, indicating that doping was successful. The FTIR spectra indicated that Zn2+ and Ni2+ doping in the HAp network did not change the vibrational modes of the main HAp functional groups. The SEM-FEG micrographs demonstrated an agglomeration of the morphology of the particles in accordance with the increase in the amount of the dopant, having irregular needle-like shapes. The gap energy of HAp doped and co-doped with zinc and nickel ranged from 5.75 eV to 2.89 eV. The photocatalytic properties through the degradation of methylene blue dye (MB) under UV and solar irradiation were investigated, as well as the antimicrobial activity against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. The results of the photocatalytic activity indicated 66.81% of dye degradation under UV irradiation for the H5Z sample. For solar irradiation, the H5Z sample showed the highest degradation of 97.85%. The antimicrobial activity results showed that the H5Z, H5Z5N, H10Z5N, H15Z5N and H5N samples showed an inhibition zone of 18.5; 14.5; 18; 17 and 5.5 mm, respectively, against gram negative bacteria (Escherichia coli), indicating the antibacterial effect of the synthesized samples.

COMMITTEE MEMBERS:
Presidente - 1802888 - FABIANA VILLELA DA MOTTA
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externa à Instituição - ANA PAULA DE AZEVEDO MARQUES - UNIFESP