Preparation of drug-montmorillonite UV-radiation protection compounds by gas-solid adsorption

Clay Minerals ◽  
2001 ◽  
Vol 36 (4) ◽  
pp. 541-546 ◽  
Author(s):  
C. del Hoyo ◽  
M. A. Vicente ◽  
V. Rives
Keyword(s):  
High Temperature ◽  
Ultraviolet Radiation ◽  
Interlayer Space ◽  
External Surface ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Clay Surface ◽  
Intercalation Complexes ◽  
Pure Drug

AbstractEthyl cinnamate/montmorillonite intercalation complexes were obtained by gaseous adsorption of the drug on the clay surface. They were characterized by powder X-ray diffraction, differential thermal and thermogravimetric analyses and by visible-UV and IR spectroscopies. It was found that after 1 day of adsorption, most of the drug enters the interlayer space of the clay by substitution of water molecules, and is removed only after heating at high temperature. In addition, a portion is physisorbed on the external surface of the crystallites, being removed easily below 100°C. The interlayer complex improves the protecting ability of the pure clay or the pure drug against ultraviolet radiation, specially in the so-called ‘C’ range (290–190 nm).

Room temperature conversion of X0.3V2O5· nH2O phase into X2V6O16· nH2O phase Influence of the nature of the cation X+

2004 ◽  
Vol 848 ◽  
Author(s):  
Olivier Durupthy ◽  
Saïd Es-salhi ◽  
Nathalie Steunou ◽  
Thibaud Coradin ◽  
Jacques Livage
Keyword(s):  
Vanadium Oxide ◽  
Room Temperature ◽  
Interlayer Space ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Phases ◽  
New Phase ◽  
Supernatant Solution ◽  
Scanning Electron

ABSTRACTVarious cations (Li+, Na+, K+, NH4+, Cs+, Mg2+, Ca2+, Ba2+) were introduced during the formation of a V2O5. nH2O gel. Cation intercalated Xy V2O5. nH2O (y = 0.3 for X = Li+, Na+, K+, NH4+ or y = 0.15 for Mg2+, Ca2+, Ba2+) were first obtained at room temperature but some of them evolve upon ageing into a new phase: XV3O8. nH2O for X = Na+, K+, NH4+ and Cs+ or XV6O16. nH2O for X = Mg2+, Ca2+, Ba2+. All the vanadium oxide phases were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR); the supernatant solutions were analysed by 51V NMR spectroscopy. These vanadium oxide phases exhibit a layered structure with cations and water molecules intercalated within the interlayer space. The formation of the different phases depends mainly on the pH of the supernatant solution and on the nature of the cation.

Effect of thermal treatment on lanthanide montmorillonites: dehydration

Clay Minerals ◽  
1980 ◽  
Vol 15 (4) ◽  
pp. 421-428 ◽  
Author(s):  
T. Mozas ◽  
S. Bruque ◽  
A. Rodriguez
Keyword(s):  
Thermal Analysis ◽  
Thermal Treatment ◽  
Interlayer Space ◽  
Lanthanide Ions ◽  
Water Molecules ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
X Ray ◽  
Water Layers

AbstractHydration/dehydration behaviour and the effect of various thermal treatments on montmorillonites saturated with lanthanide ions have been investigated by X-ray diffraction, thermal analysis (DTA, TG, DTG), IR spectroscopy and sorption-desorption of water vapour techniques. Heating at 150°C under 10−5 torr did not eliminate all the interlayer water of the montmorillonite, neither did it affect the CEC. Heating above 160°C caused a reduction in CEC. At 25°C La-montmorillonite takes up a maximum of three water layers in the interlayer space, the water molecules adopting a nonacoordinated distribution around the La3+ cation.

Spatial Location of Zerovalent Iron Nanoparticles in Montmorillonite

2011 ◽  
Vol 418-420 ◽  
pp. 674-678
Author(s):  
Ming De Fan ◽  
Jiao Hao ◽  
Yuan Zhang ◽  
Gui Dong Jing
Keyword(s):  
Electron Microscopy ◽  
Iron Nanoparticles ◽  
Interlayer Space ◽  
External Surface ◽  
Spatial Location ◽  
Zerovalent Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Zerovalent Iron Nanoparticles

The spatial location of zerovalent iron nanoparticles hybridized with montmorillonite was identified with easily accessible X-ray diffraction, transmission electron microscopy, and element analyses. These hybridized nanoparticles are not intercalated into the interlayer space of clay whereas mainly located on the external surface of clay. This result would be of great importance for the sorption-based applications of these heterostructures.

scholarly journals Adsorption of Pharmaceuticals onto Smectite Clay Minerals: A Combined Experimental and Theoretical Study

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Gwenaëlle Corbin ◽  
Emmanuelle Vulliet ◽  
Bruno Lanson ◽  
Albert Rimola ◽  
Pierre Mignon
Keyword(s):  
Interlayer Space ◽  
Theoretical Study ◽  
Van Der Waals Interactions ◽  
X Ray Diffraction ◽  
Basal Surface ◽  
Smectite Clay ◽  
X Ray ◽  
Clay Surface ◽  
Cation Coordination ◽  
Dynamics Simulations

The adsorption of two pharmaceuticals, carbamazepine and paracetamol, onto the expandable clay mineral saponite has been studied through the combination of kinetic experiments, X-ray diffraction, and theoretical modeling. Kinetic experiments indicate low adsorption for carbamazepine and paracetamol on expandable smectite clay. Accordingly, X-ray diffraction experiments show that neither compound enters smectite interlayer space. Molecular dynamics simulations were carried out to understand the interactions between the two pharmaceuticals and the saponite basal surface in the presence of Na+ cations. Calculations reveal that paracetamol almost does not coordinate solution cations, whereas a rather low coordination to cation is observed for carbamazepine. As a result, the adsorption onto the clay surface results mainly from van der Waals interactions for both pharmaceuticals. Carbamazepine does adsorb the surface via two configurations, one involving cation coordination, which corresponds to a rather stable adsorption compared to paracetamol. This is confirmed by structural analyses completed with desorption free energy profile.

High temperature X-ray diffraction investigation of an aluminium-silicon-corundum system

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 369-374 ◽  
Author(s):  
D. Garipoli ◽  
P. Bergese ◽  
E. Bontempi ◽  
M. Minicucci ◽  
A. Di Cicco ◽  
...  
Keyword(s):  
High Temperature ◽  
X Ray Diffraction ◽  
X Ray

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

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