title: Modification of Wyoming montmorillonite surfaces using a cationic surfactant.
abstract: Surfaces of Wyoming SWy-2-Na-montmorillonite were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant octadecyltrimethylammonium bromide (ODTMA). Changes in the surfaces and structure were characterized using X-ray diffraction (XRD), thermal analysis (TG), and electron microscopy. The ultrasonic preparation method results in a higher surfactant concentration within the montmorillonite interlayer when compared with that from the hydrothermal method. Three different molecular environments for surfactants within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. Both XRD patterns and TEM images demonstrate that SWy-2-Na-montmorillonite contains superlayers. TEM images of organoclays prepared at high surfactant concentrations show alternate basal spacings between neighboring layers. SEM images show that modification with surfactant reduces the clay particle size and aggregation. Organoclays prepared at low surfactant concentration display curved flakes, whereas they become flat with increasing intercalated surfactant. Novel surfactant-modified montmorillonite results in the formation of new nanophases with the potential for the removal of organic impurities from aqueous media.
authors.affiliation: Inorganic Materials Research Group, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Qld 4001, Australia.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Hongping
authors.initials: H
authors.lastname: He
authors.forename: Theo
authors.initials: T
authors.lastname: Kloprogge
authors.forename: Thor
authors.initials: T
authors.lastname: Bostrom
mesh_terms: D000327:Adsorption; D000473:Alkanes / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D008854:Microscopy, Electron / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D010316:Particle Size; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D013818:Thermogravimetry / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D000473:Alkanes; D002412:Cations; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C518260:octadecyltrimethylammonium bromide; D001546:Bentonite