Utiliza??o da Ipomoea pes-caprae (L.) Br. Convolvulaceae em sistema microemulsionado na inibi??o ? corros?o do a?o carbono

• Main Author: Cardozo, Jussara C?mara
• Other Authors: 13893734449
• Language: Portuguese
• Published: PROGRAMA DE P?S-GRADUA??O EM QU?MICA 2017
• Subjects: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Ipomoea pes-caprae; Inibidor; Corros?o; Sistema microemulsionado
• Online Access: https://repositorio.ufrn.br/jspui/handle/123456789/22375

Submitted by Automa??o e Estat?stica ([e-mail]) on 2017-03-20T19:31:23Z No. of bitstreams: 1 JussaraCamaraCardozo_DISSERT.pdf: 2268880 bytes, checksum: 954a81448f427aec51a29c591fac9967 (MD5) === Approved for entry into archive by Arlan Eloi Leite Silva ([e-mail]) on 2017-03-21T23:23:40Z (GMT) No. of bitstreams: 1 JussaraCamaraCardozo_DISSERT.pdf: 2268880 bytes, checksum: 954a81448f427aec51a29c591fac9967 (MD5) === Made available in DSpace on 2017-03-21T23:23:40Z (GMT). No. of bitstreams: 1 JussaraCamaraCardozo_DISSERT.pdf: 2268880 bytes, checksum: 954a81448f427aec51a29c591fac9967 (MD5) Previous issue date: 2016-07-26 === Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) === Os problemas provenientes da a??o corrosiva refletem diretamente no setor financeiro das ind?strias, no meio ambiente e seguran?a, com isso aumenta-se a necessidade de combater esse problema de forma mais efetiva poss?vel vinculando a efici?ncia de inibi??o a produtos naturais que minimizam os impactos ambientais. Neste contexto, o presente trabalho utiliza sistemas microemulsionados (SME), SME com fra??o de Taninos (SME-T) e SME com fra??o de Taninos e Saponinas (SME-TS) bem como os Taninos e Saponinas de forma livre como inibidores de corros?o para o a?o carbono AISI 1018 sob a influ?ncia do meio corrosivo de NaCl 3,5%. As efici?ncias de inibi??es ? corros?o e seus mecanismos foram investigados atrav?s das curvas de polariza??o e isotermas de adsor??o. As fra??es de Taninos e saponinas, apresentaram respectivamente, efici?ncias de inibi??es ? corros?o m?ximas de 80,82% (75 ppm) e 50,21% (200 ppm) em velocidade de varredura de 1mVs-1. O sistema microemulsionado SME apresenta efici?ncia m?xima de 59,56% (50 ppm), por?m com a solubiliza??o de Tanino (5,0x10-5 g) a efici?ncia de inibi??o alcan?ou 65,67% (100 ppm do SME-T) e com a solubiliza??o de Taninos e Saponinas na propor??o de 1:1 (7,6x10-5 g) obteve efici?ncia m?xima 81,30% (75 ppm) para o SME-TS. Com rela??o ao processo de adsor??o, os dados experimentais de todos os inibidores testados se ajustaram a isoterma de Langmuir. A partir dos valores de energia de Gibbs foi visto que a forma??o do filme interfacial acontece espontaneamente e ? resultado as intera??es do tipo f?sicas entre as mol?culas inibidoras com os s?tios ativos do metal. A partir do estudo da influ?ncia da velocidade de varredura na an?lise eletroqu?mica foi visto que a velocidade de 1 mVs-1 forneceram melhores resultados de efici?ncia de inibi??o da corros?o do a?o carbono se comparado com a velocidade de 10 mVs-1. Contudo a solubiliza??o dos taninos e saponinas nos sistemas microemulsionados foi vi?vel no ponto de vista de diminui??o do uso do material vegetal e os sistemas tornam-se uma boa alternativa para utiliza??o como inibidor que n?o agride o meio ambiente, de f?cil acesso, de baixo custo, renov?vel e n?o t?xico. === The problems related to corrosive action have a direct impact on the industry financial sector, environment and safety, which increases the necessity to fight such problem in the most effective way possible, associating the efficiency of inhibition to natural products that are able to minimize environment impacts. In this context, this study uses microemulsion systems (SME), SME with fraction of Tannins (SME-T) and SME with fractions of both Tannins and Saponins (SME-TS) as well as free-form Tannins and Saponins with corrosive inhibitors of the carbon steel AISI 1018 under the influence of a 3.5% NaCl corrosive mean. The corrosive inhibition efficiency and its mechanisms were investigated through polarization curves and adsorption isotherms. The tannin and saponin fractions showed maximum inhibition efficiencies of 80.82% (75 ppm) and 50.21% (200 ppm) in a 1mVs-1 scan speed. The microemulsion system SME shows maximum efficiency of 59.56% (50 ppm). However, with the solubilization of the Tannins (5.0x10-5 g) the inhibition efficiency reached 65.67% (100 ppm of the SME-T) and with the solubilization of the Tannins and Saponins in the proportion of 1:1 (7.6x10-5 g) performed a 81.30% (75 ppm) maximum efficiency to the SME-TS. Regarding the absorption process, the results of all the tested inhibitors adjust to the Langmuir isotherm. Observing the energy values of Gibbs, it was understood that the interfacial film formation happens spontaneously and it is resulting from the physic interactions between the inhibition molecules with other active metal sites. Considering the scan speed study in the electrochemical analysis, it was observed that the speed of 1 mVs-1 led to better results of corrosive inhibition efficiency of the carbon steel when compared to the speed of 10 mVs-1. In spite of that, the tannins and saponins solubilization in the microemulsion systems was feasible regarding the decrease in the use of vegetal material, and the systems represent a good alternative inhibitor to does not harm the environment, which is easy to find, low-cost, renewable and non-toxic.