Modelagem multiescala do acoplamento eletro-químico em um meio poroso argiloso com dependência do PH

• Ano de defesa: 2007
• Autor(a) principal: Lima, Sidarta Araújo de
• Orientador(a): Murad, Marcio Arab
• Banca de defesa: Stemmelen, Didier , Galeão, Augusto Cesar Noronha Rodrigues , Dardenne, Laurent Emmanuel, Azevedo, Roberto Francisco de, Lomba, Rosana
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Laboratório Nacional de Computação Científica
• Programa de Pós-Graduação: Programa de Pós-Graduação em Modelagem Computacional
• Departamento: Serviço de Análise e Apoio a Formação de Recursos Humanos
• País: BR
• Palavras-chave em Português: Modelagem Multiescala; Fenônemos Eletroquímicos; Argilas.
• Palavras-chave em Inglês: Multiscale Modeling; Eletro-Chemical Couplings.
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
• Link de acesso: https://tede.lncc.br/handle/tede/79

In this work we develop a three-scale mathematical modeling to describe electro-chemical couplings in clays using the asymptotic homogenization procedure of periodic structures. We consider the porous medium composed of kaolinite particles saturated by an electrolyte solution of water-solvent and four ionic solutes monovalents Na+, H+, Cl-, OH-At the nanoscale we develop the model of the electrical double layer wherein the electric potential and local charge distribution are ruled by the Poisson- Boltzmann problem. In addition we incorporate the protonation/deprotonation chemical reaction between the fluid and the particle surface and consequently we quantify the dependence of the surface charge density of the particles with the pH of the electrolyte solution. At the microscale, or pore-scale, the movement of the aqueous solution is governed by the Stokes problem whereas ion transport by the Nernst-Planck equation. The pore-scale governing equations are supplemented by slip boundary condition in the tangential velocity of the fluid and adsorption interface conditions arising from the averaging of the nanoscale model. We then homogenize the microscopic model to the macroscale and derive effective equations with additional closure relations for the macroscopic coefficients. The macroscopic model is discretized by the finite volume method and numerical simulations of electrokinetical remediation of a contaminated soil are performed. The numerical results illustrate the strong dependence of the remediation efficiency on the pH of the aqueous solution.