Acid-base properties of ca-montmorillonite from benavila region (Portugal) [Propriedades ácido-base da montmorilonite cálcica da região de benavila (Portugal)]

• Tipo: Artigo em Revista Científica Internacional
• Data: 2014

Autores

Guimaraes, V (Autor) Outra; Bobos, I (Autor) FCUP; Rocha, F (Autor) Outra

Revista

Título: Comunicações Geológicas

Vol. 101

Páginas: 791-794

ISSN: 0873-948X

Editora: LNEG - Laboratório Nacional de Energia e Geologia

Indexação

ISI Web of Knowledge

Scopus - 0 Citações

Classificação Científica

CORDIS: Ciências Naturais

FOS: Ciências exactas e naturais

Projetos Associados

KADRWaste - Estudo de Mecanismos e Cinética de Adsorção em Geomateriais e sua caracterização estrutural: implicações para os processos de atenuação natural da contaminação em metais pesados e confinamento de resíduos radioactivos - KADRWaste

Outras Informações

ID Authenticus: P-00G-KA2

Abstract (EN): Montmorillonite is a dioctahedral (2:1) phyllosilicate mineral that plays an important role in many industrial and environment applications. Due to their peculiar physicochemical properties, mainly controlled by electrostatic interactions, the study of the acid-base properties of this material has been a subject of great importance in the last years. Thus, the understanding of the surface charge variation of montmorillonite, in order to obtain a better control of their physicochemical properties, become crucial. The main goal of this research is to study the surface properties of montmorillonite, through the acid-base titrations of its suspension, under different conditions of ionic strength ([NaCl]=0.01M and [NaCl]=0.1M). The titration data was interpreted by surface complexation models (NEM and CCM) taking into account an ideal behavior of the surface species, where the electrostatic interactions are ignored (NEM), and the presence of an electrical double layer (EDL) at the mineral-water interface where the electrostatic terms are involved (CCM). The results show that 6 different species are involved on the protonation and deprotonation of surface sites: two acidic species (strong-SiOH<inf>2</inf> + and weak-AlOH<inf>2</inf> +), two neutral species (SiOH and AlOH) and two basic species (weak-SiO- and strong-AlO-). The surface parameters obtained by the two models (NEM and CCM) are close to the same. However, it was concluded that the electrostatic influence become more significant as pH increases. © 2014, LNEG ¿ Laboratório Nacional de Geologia e Energia IP.

Idioma: Inglês

Tipo (Avaliação Docente): Científica