title: Chemical, structural, and thermal properties of Zn(II)-Cr(III) layered double hydroxides intercalated with sulfated and sulfonated surfactants.
abstract: Zn(II)-Cr(III)-LDHs (layered double hydroxides) containing sulfated or sulfonated surfactants as the interlamellar anion were synthesized by the coprecipitation method. The syntheses were conducted under various different experimental conditions, such as the Zn : Cr ratio, pH, and aging time. In each of the prepared materials, unlike previously reported data, the interlayer anion arrangement did not change, being consistent with a perpendicular monolayer. The thermal decomposition process of the prepared materials was studied by a set of analysis methods, such as TG/DTA, TG/MS, PXRD, and FT-IR. From the results obtained it was possible to conclude that, in an air atmosphere, the anions decomposed by a partial combustion, leading to the formation of sulfide. The results also showed that sulfonated surfactants containing LDHs are much more stable than those containing sulfated surfactants. A mechanism was proposed for the thermal decomposition of such LDHs based on the experimental results.
authors.affiliation: Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, University of São Paulo, Av. dos Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil.
authors.forename: Eduardo Luis
authors.initials: EL
authors.lastname: Crepaldi
authors.forename: Paulo César
authors.initials: PC
authors.lastname: Pavan
authors.forename: Jairo
authors.initials: J
authors.lastname: Tronto
authors.forename: João Barros
authors.initials: JB
authors.lastname: Valim
mesh_terms: D001557:Benzenesulfonates / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D015032:Zinc / Q000737:chemistry*
chemical_list: D001557:Benzenesulfonates; D006878:Hydroxides; D013431:Sulfates; D013501:Surface-Active Agents; D002857:Chromium; D015032:Zinc