Identification and quantification of the interaction mechanisms between the cationic surfactant HDTMA-Br and montmorillonite

• Published in: Clays and clay minerals Vol. 61; no. 2; pp. 98 - 106
• Main Authors: Naranjo, Pablo M, Sham, Edgardo L, Castellón, Enrique Rodríguez, Torres Sánchez, Rosa M, Farfán Torres, Elsa M
• Format: Journal Article
• Language: English
• Published: Cham Clay Minerals Society 01-04-2013; The Clay Minerals Society; Springer International Publishing
• Subjects: Adsorption; Alkylammonium Molecules; Biogeosciences; cation exchange capacity; Cationic; Cationic Surfactant Hdtma-Br; Cations; chemical composition; chemical properties; clay minerals; Clays; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Exact sciences and technology; experimental studies; Geochemistry; halogenated hydrocarbons; identification; Medicinal Chemistry; methyl bromide; Mineralogy; molecular dynamics; Montmorillonite; Nanoscale Science and Technology; organic compounds; quantitative analysis; rock, sediment, soil; sed rocks, sediments; Sedimentary petrology; sheet silicates; Silicates; Soil Science & Conservation; Surface chemistry; Surfactants; X-ray photoelectron spectroscopy; Montmorillonite; Cationic Surfactant HDTMA-Br; Alkylammonium molecules; models; adsorption; cations; bromides; cation exchange capacity; X-rays; isotherms; halides; smectite; clay; sedimentary rocks; montmorillonite; physicochemical properties; spectroscopy; clay minerals; sheet silicates; silicates; ions; clastic rocks; thermal analysis
• ISSN: 0009-8604; 1552-8367
• DOI: 10.1346/CCMN.2013.0610208

Several detailed studies have been done on the characterization of organoclays and the type of structures developed when they interact with alkylammonium molecules. Few published contributions exist, however, on the distribution of surfactant within the organoclays and the mechanism by which they are intercalated. Also, although X-ray photoelectron spectroscopy (XPS) is a suitable technique for the study of the surface characteristics of organoclays, very few such XPS studies have been carried out. With the aim of contributing to a better understanding of the intercalation process, a series of organoclays was synthesized using a montmorillonite and the cationic surfactant hexadecyltrimethylammonium bromide (HDTMABr), with an increasing surfactant load of between 0.2 and 4.0 times the cation exchange capacity of the starting clay. By means of XPS, zeta potential, and thermal analysis techniques, distinguishing the strongly interacting fraction from the weakly interacting fraction of the adsorbed surfactant molecules was possible. Adsorption isotherms of each of these processes were constructed and then adjusted using the Langmuir and Dubinin-Radusquevich adsorption models. Three types of interaction between the surfactant and the clay were identified and described qualitatively and quantitatively. Two of these interactions, strong and weak, involved the hexadecyltrimethylammonium cation (HDTMA+). The third was a weak interaction involving the ion pair HDTMA+Br-. The results of this study may be useful for the comprehensive design of organoclays with specific physicochemical properties according to the application for which they are destined.