title: Study of cetyltrimethylammonium and cetylpyridinium adsorption on montmorillonite.
abstract: Adsorption of cetyltrimethylammonium (CTA) and cetylpyridinium (CP) onto Na-rich montmorillonite (MMT) was studied. For this purpose, the adsorption isotherms of CTA and CP, along with desorption curves of metal cations (Na+, K+, Ca2+, Mg2+), were obtained by means of capillary isotachophoresis and atomic absorption spectrometry. Infrared, X-ray diffraction pattern, specific surface area, porosity, and moisture adsorption measurements of montmorillonite revealed that CTA and CP were adsorbed in monolayer arrangements. CTA is assumed to be attached to the negatively charged MMT surface mainly by electrostatic forces. On the other hand, CP, adsorbed in higher amounts, can be additionally bound via other interactions of pyridinium rings, such as induced and pi-pi interactions. By the surfactant adsorption, the montmorillonite surface became hydrophobic and its micro- and mesopores were significantly diminished. Using scanning electron microscopy, aggregation of such organically modified MMT particles was observed.
authors.affiliation: Department of Analytical Chemistry and Material Testing, VSB-Technical University Ostrava, 17 Listopadu 15, 708 33 Ostrava, Czech Republic. petr.praus@vsb.cz
authors.forename: Petr
authors.initials: P
authors.lastname: Praus
authors.forename: Martina
authors.initials: M
authors.lastname: Turicová
authors.forename: Sona
authors.initials: S
authors.lastname: Studentová
authors.forename: Michal
authors.initials: M
authors.lastname: Ritz
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002593:Cetrimonium Compounds / Q000737:chemistry*; D002594:Cetylpyridinium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D010316:Particle Size; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D002593:Cetrimonium Compounds; D001546:Bentonite; D002594:Cetylpyridinium