02793nas a2200181   4500008004100000022001400041245011300055210006900168260007100237300001600308490000700324520207000331100001902401700001902420700002002439700002302459856012902482       2009                        eng d  a0743-746300aAzoic dye hosted in layered double hydroxide: physicochemical characterization of the intercalated materials0 aAzoic dye hosted in layered double hydroxide physicochemical cha  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP  a10980-109860 v253 a<p>Intercalation compounds were obtained by introduction of guest methyl orange (MO) into the interlayer space of host Mg/Al and Ni/Al layered double hydroxides (LDHs). Three synthesis methods of organic anion-LDH intercalation compounds, i.e., coprecipitation, reconstruction of the M(II)(Al)O mixed oxides, and anion exchange of LDH were compared. The former Method gives rise to a highly organized MO-intercalated Mg/Al LDH with an interlayer spacing of 2.43 rim and up to seven (001) reflection orders. Reconstruction or the mixed oxide by intercalation with MO in the restored LDH was only achieved with Mg(Al)O. In this case. a competitive adsorption of MO on the external Surface Of the crystals was also seen. On the other hand, intercalation compounds exhibiting interlayer spacing of 2.43 run were obtained with both Mg- and Ni-containing LDH using the anionic exchange method. The equilibrium and kinetic adsorption properties of the compounds were analyzed by UV-visible spectroscopy in anionic exchange experiments. According to the pseudo-second-order adsorption model, the amounts of adsorbed MO reach 3.82 and 2.83 mequiv/g for Mg- and Ni-containing LDHs, respectively, which are close to their respective anionic exchange capacity. The adsorption rates are on the same order of magnitude for the two LDHs (0.10-0.44 g mmol(-1) min(-1)), the equilibrium being reached in less than 60 min. The decomposition of MO by combustion of the organic moieties under an oxidizing atmosphere is delayed in Mg-containing MO-LDH hybrids when compared to the free MO molecule, showing that the thermal stability of MO species is enhanced after intercalation. In Ni-containing LDH, the main decomposition step of MO occurs 300 degrees C below that of Mg-containing LDH. This was rationalized in terms of a catalysis by the Ni-containing oxides formed during the thermal treatment. So these materials exhibit several advantage useful for the development of eco-friendly processes for the removal Of dyes from effluents of textile, plastic, and paper industries.</p>1 aMandal, Sujata1 aTichit, Didier1 aLerner, Dan, A.1 aMarcotte, Nathalie  uhttps://library.ncl.res.in/content/azoic-dye-hosted-layered-double-hydroxide-physicochemical-characterization-intercalated-002268nas a2200241   4500008004100000022001400041245007800055210006900133260008600202300001200288490000800300520141800308653002101726653001601747653003001763653001801793653002201811100001901833700002001852700002301872700001901895856011201914       2009                        eng d  a0044-296800aStructural characterization of azoic dye hosted layered double hydroxides0 aStructural characterization of azoic dye hosted layered double h  aLEKTORAT MINT, POSTFACH 80 13 60, D-81613 MUNICH, GERMANYbOLDENBOURG VERLAGcJAN  a282-2860 v2243 a<p>The removal of methyl orange (MO) from an aqueous solution was performed using layered double hydroxides (LDHs) in a move to develop cleaning processes of effluents contaminated with dye molecules. The intercalation of the guest anionic MO species into host M(II)/Al(III) LDHs differing by the nature of the divalent cations (M(II) = Mg, Ni or Zn) was achieved by anionic exchange of the initially NO(3)(-) present in the interlayer space and led to MO/LDH intercalation compounds. The exchange process was followed by XRD and UV-visible absorption spectroscopy at different stages. Almost all MO in solution is uptaken by the Mg-containing LDH in the concentration range corresponding to its anionic exchange capacity (AEC). A lower exchange is reached with the Ni- and Zn-containing LDHs, for which the diffusion of MO is limited due to a larger crystallite size. MO-Zn/Al LDH intercalation compounds exhibit the highest crystallinity and display a remarkable stacking of the layers at maximal MO exchange. This behaviour can be assigned to the higher intrinsic charge density of the host layers in agreement with its lower M(II)/Al(III) molar ratio (Zn(II)/Al(III) approximate to 1.5 whereas Mg(II)/Al(III) and Ni(II)/Al(III) = 2). The maximum amount of MO retained by the different LDHs is higher for Mg-containing LDH, than for Ni- and Zn-containing LDH, reaching respectively 1.15, 0.84 and 0.77 g/g.</p>10aAnionic exchange10aDepollution10alayered double hydroxides10aMethyl orange10aX-ray diffraction1 aMandal, Sujata1 aLerner, Dan, A.1 aMarcotte, Nathalie1 aTichit, Didier  uhttps://library.ncl.res.in/content/structural-characterization-azoic-dye-hosted-layered-double-hydroxides-0