01983nas a2200241 4500008004100000022001400041245009600055210006900151260010500220300001200325490000700337520111900344653002301463653001501486653000901501653001801510653001801528100001901546700002101565700001701586700001501603856012301618 2005 eng d a0250-470700aSilver nanoparticles of variable morphology synthesized in aqueous foams as novel templates0 aSilver nanoparticles of variable morphology synthesized in aqueo aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACADEMY SCIENCEScAUG a503-5100 v283 a

In this paper, we describe the synthesis of silver nanocrystals within aqueous foams as a template More specifically, we show that aqueous Ag+ ions may be electrostatically complexed with the anionic surfactants aerosol OT (sodium bis-2-ethylhexyl-sulfosuccinate, (AOT) and sodium dodecyl sulphate (SDS)) in a highly stable liquid foam. After drainage of the foam, the silver ions are reduced in situ by introducing sodium borohydride into the foam by capillary flow. This leads to the formation of silver nanoparticles of spherical, tape- and sheet-like morphology in the foam. The structure of the foam is extremely complex and presents reaction sites of different spatial extent. The differences in foam reaction-site geometry are believed to be responsible for the morphology variation in the silver nanoparticles observed. The silver nanoparticles are observed to be extremely stable in solution suggesting that the AOT or SDS molecules stabilize them. This approach appears promising for application in large-scale synthesis of nanoparticles and may be readily extended to other chemical compositions.

10aChemical synthesis10acomposites10afoam10aIntercalation10aNanoparticles1 aMandal, Sujata1 aArumugam, S., K.1 aPasricha, R.1 aSastry, M. uhttp://library.ncl.res.in/content/silver-nanoparticles-variable-morphology-synthesized-aqueous-foams-novel-templates-001195nas a2200169 4500008004100000022001400041245010300055210006900158260007700227300001200304490000700316520053000323100001500853700001900868700001500887856012300902 2005 eng d a1616-301X00aSynthesis and assembly of gold nanoparticles in quasi-linear lysine-keggin-ion colloidal particles0 aSynthesis and assembly of gold nanoparticles in quasilinear lysi aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB a273-2800 v153 a

The formation of fiber-like colloidal particles of the amino acid lysine complexed with Keggin ions is demonstrated. The lysine-phosphotungstic acid (PTA) colloidal particles act as excellent templates for the synthesis and assembly of gold nanoparticles wherein the lysine-PTA complex acts as a UV-switchable reducing agent for gold ions. This novel bio-organic-inorganic template shows excellent potential as a regulated nanoreactor for application in programmed nanoparticle synthesis and assembly in a single step.

1 aSanyal, A.1 aMandal, Sujata1 aSastry, M. uhttp://library.ncl.res.in/content/synthesis-and-assembly-gold-nanoparticles-quasi-linear-lysine-keggin-ion-colloidal-001901nas a2200169 4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520124000314100001701554700001901571700001501590856012601605 2005 eng d a0743-746300aSynthesis of hydroxyapatite crystals using amino acid-capped gold nanoparticles as a scaffold0 aSynthesis of hydroxyapatite crystals using amino acidcapped gold a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY a5185-51910 v213 a

Inorganic composites are of special interest for biomedical applications such as in dental and bone implants wherein the ability to modulate the morphology and size of the inorganic crystals is important. One interesting possibility to control the size of inorganic crystals is to grow them on nanoparticles. We report here the use of surface-modified gold nanoparticles as templates for the growth of hydroxyapatite crystals. Crystal growth is promoted by a monolayer of aspartic acid bound to the surface of the gold nanoparticles; the carboxylate ions in aspartic acid are excellent hinging sites for Ca2+ ions. Isothermal titration calorimetry studies of Ca2+ ion binding with aspartic acid-capped gold nanoparticles indicates that the process is entropically driven and that screening of the negative charge by the metal ions leads to their aggregation. The aggregates of gold nanopartictes are believed to be responsible for assembly of the platelike hydroxyapatite crystals into quasi-spherical superstructures. Control experiments using uncapped gold nanoparticles and pure aspartic acid indicate that the amino acid bound to the nanogold surface plays a key role in inducing and directing hydroxyapatite crystal growth.

1 aRautaray, D.1 aMandal, Sujata1 aSastry, M. uhttp://library.ncl.res.in/content/synthesis-hydroxyapatite-crystals-using-amino-acid-capped-gold-nanoparticles-scaffold-002267nas a2200241 4500008004100000022001400041245007800055210006900133260008600202300001200288490000800300520141800308653002101726653001601747653003001763653001801793653002201811100001901833700002001852700002301872700001901895856011101914 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

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.

10aAnionic exchange10aDepollution10alayered double hydroxides10aMethyl orange10aX-ray diffraction1 aMandal, Sujata1 aLerner, Dan, A.1 aMarcotte, Nathalie1 aTichit, Didier uhttp://library.ncl.res.in/content/structural-characterization-azoic-dye-hosted-layered-double-hydroxides-002177nas a2200241 4500008004100000022001400041245011600055210006900171260000800240300001200248490000700260520134600267653002401613653002401637653002901661653002201690100001701712700002101729700002001750700001601770700001901786856013001805 2024 eng d a0971-457X00aSynthetic layered double hydroxide on biodegradable support: an efficient adsorbent for defluoridation of water0 aSynthetic layered double hydroxide on biodegradable support an e cJAN a152-1610 v313 a

Fluoride concentrations in drinking water above permissible levels and incidences of fluorosis among people have been reported from many parts of the world including India. Low-cost and biodegradable adsorbents are the preferred choice for the removal of fluoride from an aqueous medium. In the present study, zinc-aluminium layered double hydroxide (LDH) supported on sugarcane bagasse (raw and acid-treated) has been synthesized, characterized, and investigated for the defluoridation of water. The SEM micrographs of the supported adsorbents show good dispersion of the LDH particles on the support material. The defluoridation capacity of the LDH is enhanced by supporting it on bagasse. The adsorption capacity of supported adsorbents increased by 3-fold than the unsupported LDH adsorbent. The adsorption data have been well fitted to the Freundlich isotherm model indicating physical and multi-layer adsorption. The maximum fluoride adsorption capacity has been found to be 8.85 mg/g with 76.3% fluoride removal when the initial fluoride concentration is 11-12 mg/L. The pseudo-second-order kinetic model has been found suitable to explain the fluoride adsorption kinetics on the supported LDH adsorbents. The present study reveals that the bagasse-supported LDH adsorbent has a high potential for defluoridation of water.

10aadsorption kinetics10aFluoride adsorption10aLayered double hydroxide10aSugarcane bagasse1 aMayadevi, S.1 aKirandas, M., D.1 aManilal, A., M.1 aRoshini, N.1 aMandal, Sujata uhttp://library.ncl.res.in/content/synthetic-layered-double-hydroxide-biodegradable-support-efficient-adsorbent-defluoridation