ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A new approach about the intercalation of hexadecyltrimethylammonium into halloysite: preparation, characterization, and mechanism

Khouira Mehdi, Souhila Bendenia, Gisele Laure Lecomte-Nana, Isabelle Batonneau-Gener, Fabrice Rossignol, Kheira Marouf-Khelifa, and Amine Khelifa

Université de Mostaganem, Mostaganem, Algeria

E-mail: aminekhelifadz@yahoo.fr

Abstract: Three organoclays were prepared by mixing an Algerian halloysite with a solution of hexadecyltrimethylammonium bromide (HDTMA-Br) equivalent to six times the cation-exchange capacity of our clay. Unlike a majority of studies which were focused on the initial concentration of the intercalating agent, this paper investigates the influence of the reaction time for a given initial concentration. Three intercalation times were examined: 2, 7, and 14 days. The resulting organoclays were analyzed by XRD, FTIR, TG–DTA, TEM, and N₂ adsorption–desorption. The intercalation of HDTMA⁺ cations begins by a latency period up to 2 days, during which these cations interact with the external surface of halloysite. From 2 to 7 days, they migrate into the interlayer spaces, leading to an expansion of the basal distance from 7.3 to 26.0 Å. Between 7 and 14 days, the expansion remains unchanged for an intercalation rate around 42%. FTIR analysis proved that the surfactant interacts with the inner surface hydroxyl groups. From 200 °C, thermal analysis highlighted a succession of stages linked to the removal of HDTMA⁺. The TEM images showed a decrease in the outer diameter of the intercalated nanotubes with an enlargement of lumen diameter up to 20 nm. The arrangement of HDTMA⁺ species into interlayer spaces reflected a paraffin-type monolayer configuration. Knowing that the intercalation of organic compounds into the clay minerals changes their behavior from hydrophilic to hydrophobic, a nanotubular organohalloysite with a basal expansion of 26.0 Å could be a highly effective adsorbent for wastewater decontamination.

Keywords: Halloysite ; Intercalation ; Hexadecyltrimethylammonium bromide ; Characterization ; XRD analysis ; Mechanism 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0558-8

Chemical Papers 73 (1) 131–139 (2019)