A versatilidade das argilas e as propriedades dos sítios superficiais de interação

Abstract

This article presents in a simplified and introductory way, the active sites present on the surfaces of clays that make them so versatile. These sites are responsible for interactions between the clay and organic or inorganic species, and the chemical transformations of substrates that occur on the surface, allowing to understand either natural processes in the environment or those performed on an industrial scale. It is proposed that this text can illustrate, in the classroom, fundamental concepts (types of chemical reactions, electrostatic interactions and other ones) from processes on solid surfaces. The correlation between the active sites of clays and their properties is a rich topic to be explored in chemistry disciplines.

Obtaining and Applying Nanohybrid Palygorskite-Rifampicin in the pH-Responsive Release of the Tuberculostatic Drug

“…As previously discussed, the palygorskite has a negatively charged surface over a wide pH range because of isomorphic substitution processes. The higher the degree of substitution, the greater the basic character of Lewis of the outer surface of the mineral clay . Depending on the basicity of the mineral surface, acid–base interactions may be responsible for determining the adsorption mechanisms, such as hydrogen bonding or chemical complexation …”

“…The higher the degree of substitution, the greater the basic character of Lewis of the outer surface of the mineral clay. 89 Depending on the basicity of the mineral surface, acid−base interactions may be responsible for determining the adsorption mechanisms, such as hydrogen bonding or chemical complexation. 84 Rifampicin is entirely in its cationic form (RIF+) in a pH 2 medium, presenting its basic groups (amines of the piperazine ring) ionized.…”

Determinação da área superficial específica e da porosidade de duas amostras de argilas provenientes da bacia de Taubaté- São Paulo / Determination of specific surface area and porosity of two clays originated from Taubaté- Basin – São Paulo

“…Por seu poder adsorvente podem ser empregados como peneiras moleculares, agentes descorantes e clarificantes de óleos vegetais minerais, suportes catalíticos, agentes de filtração, adsorventes de óleos em água, adsorventes de pesticidas, veículo para liberação de nutrientes inorgânicos no solo, agente de remediação ambiental por imobilização de metais pesados ou radioisótopos no meio ambiente, etc. [1][2][3][4][5][6]. A área superficial específica é uma das propriedades que exercem efeito significativo nas Brazilian Applied Science Review, Curitiba, v., n.1, p.39-57 jan/Fev.…”