A critical assessment of the methods for intercalating anionic surfactants in layered double hydroxides

dc.contributor.authorMoyo, Lumbidzani
dc.contributor.authorNhlapo, N.S. (Nontete Suzan)
dc.contributor.authorFocke, Walter Wilhelm
dc.contributor.emailwalter.focke@up.ac.zaen_US
dc.date.accessioned2009-05-07T06:49:40Z
dc.date.available2009-05-07T06:49:40Z
dc.date.issued2008-08
dc.description.abstractAnionic surfactant intercalated layered double hydroxides (LDH) of high purity are easily prepared via direct coprecipitation and also by the ion exchange method provided that the precursor contains a monovalent anion, e.g., LDH–Cl or LDH–NO3. However, LDH–CO3 is an attractive starting material as it is commercially available in bulk form owing to large-scale applications as a PVC stabilizer and acid scavenger in polyolefins. Thus, intercalation of dodecyl sulfate and dodecylbenzenesulfonate into a commercial (LDH) with approximate composition [Mg0.654Al0.346(OH)2](CO3)0.173 • 0.5H2O] was explored. Direct ion exchange is difficult as the carbonate is held tenaciously. In the regeneration method it is removed by thermal treatment and the surfactant form obtained by reaction with the layered double hydroxide that forms in aqueous medium. Unfortunately the resulting products are impure, poorly crystallized and only partial intercalation is achieved. Better results were obtained using water-soluble organic acids, e.g., acetic, butyric, or hexanoic acid, to aid decarbonation of LDH–CO3. Intercalation proceeded at ambient temperatures with the precursor powder suspended in an aqueous dispersion of the anionic surfactant. The carboxylic acids are believed to assist intercalation by facilitating the elimination of the carbonate ions present in the anionic clay galleries.en_US
dc.identifier.citationMoyo, L, Nhlapo, N & Focke, WW 2008, ‘A critical assessment of the methods for intercalating anionic surfactants in layered double hydroxides’, Journal of Materials Science, vol. 43, no. 18, pp. 6144-6158. [http://www.springer.com/materials/journal/10853]en_US
dc.identifier.issn0022-2461
dc.identifier.other10.1007/s10853-008-2935-0
dc.identifier.urihttp://hdl.handle.net/2263/9934
dc.language.isoenen_US
dc.publisherSpringeren_US
dc.rightsSpringer. The original publication is available at www.springerlink.comen_US
dc.subjectAnionic surfactanten_US
dc.subjectLarge-scale applicationsen_US
dc.subject.lcshLayered double hydroxides -- South Africa
dc.subject.lcshChemical industry -- South Africa
dc.subject.lcshSurface active agents industry -- South Africa
dc.titleA critical assessment of the methods for intercalating anionic surfactants in layered double hydroxidesen_US
dc.typePostprint Articleen_US

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