Banca de QUALIFICAÇÃO: DENISE PORFIRIO EMERENCIANO
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : DENISE PORFIRIO EMERENCIANO
DATA : 14/02/2017
HORA: 14:00
LOCAL: Sala 3F1
TÍTULO:
PREPARATION AND CHARACTERIZATION OF NEW COLLOIDAL SYSTEMS FROM VEGETABLE OILS FOR BIOTECHNOLOGICAL APPLICATIONS
PALAVRAS-CHAVES:
Azadirachta indica A. Juss., Copaifera L., Microemulsion system, Green corrosion inhibitors, Antioxidant property, Electrochemical techniques of linear polarization resistance and impedance
PÁGINAS: 130
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Eletroanalítica
RESUMO:
In this work, the corrosion inhibition efficiency in AISI 1018 steel of colloidal systems based on vegetable oils of the species Azadirachta indica A. Juss (SMEOAI) and Copaifera L. (SMECO) were evaluated by electrochemical techniques of linear polarization resistance (LPR) and impedance spectroscopy (EIS). The hydroalcoholic extract obtained from the leaves of A. indica (EAI) was used as a green corrosion inhibitor and was carried in the colloidal system SMEOAI, which was prepared by using Tween® 80 as surfactant, A. indica isolated oil (OAI) as oil phase and bidistilled water (as a neutral aqueous phase). The SMEOAI system satisfactorily loaded the HAEAI extract providing a derivative formulation so called SMEOAI-EAI. Similarly, the SMECO system was prepared by using Tween® 80, copaiba oil (CO), and bidistilled water. The formation of Winsor IV microemulsion region (WIV) on both systems (SMEOAI and SMECO) was evidenced through the construction of the ternary phase diagrams. The SMEOAI and SMECO systems characterizations were performed by using the following analyzes, determination of the refractive index, rheological behavior, surface tension and droplet diameter. The green inhibitors SMEOAI and SMECO were analyzed in different concentrations (5 ppm - 150 ppm) in corrosion of AISI 1018 steel in corrosive saline medium (3.5% NaCl solution). The results showed that the SMEOAI system presented maximum efficiency of corrosion inhibition (79.28%) in low concentration (25 ppm). The SMEOAI-EAI system showed superior inhibition efficiency to superior corrosion of 91.79% at 50ppm concentration. As a complement to this study, the antioxidant properties of the SMEOAI and SMEOAI-EAI systems, evaluated by total antioxidant capacity (CAT), hydroxyl radical sequestration (OH•), superoxide radical sequestration (O2-), metal ion chelation and reducing power, with better comparative results for the SMEOAI-EAI system. The SMECO system presented better corrosion inhibition efficiency at 100 ppm concentration (87.0%). The green corrosion inhibitors SMEOAI, SMEOAI-EAI and SMECO are biodegradable and have broad commercial value with the possibility of different applications such as, bio-insecticides, biological drug carriers, waste water purifiers, effluents, oil recovery agents, among other applications, these being some of the claims made for these bioformulates.
MEMBROS DA BANCA:
Interno - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Interno - 1803692 - FABRICIO GAVA MENEZES
Presidente - 373.201.654-49 - MARIA APARECIDA MEDEIROS MACIEL - UnP
Interno - 7350310 - MARIA DE FATIMA VITORIA DE MOURA