Synthesis and Anion Exchange Chemistry of Rhombohedral Li/Al Layered Double Hydroxides

2002 ◽  
Vol 14 (1) ◽  
pp. 232-234 ◽  
Author(s):  
Andrew M. Fogg ◽  
Amal J. Freij ◽  
Gordon M. Parkinson
Keyword(s):  
Anion Exchange ◽  
Layered Double Hydroxides ◽  
Double Hydroxides

Anion-exchange reactions of layered double hydroxides

1990 ◽  
Vol 29 (26) ◽  
pp. 5201-5207 ◽  
Author(s):  
Martina Meyn ◽  
Klaus Beneke ◽  
Gerhard Lagaly
Keyword(s):  
Anion Exchange ◽  
Layered Double Hydroxides ◽  
Exchange Reactions ◽  
Double Hydroxides

scholarly journals Liquid phase exfoliation of carbonate-intercalated layered double hydroxides

2019 ◽  
Vol 55 (23) ◽  
pp. 3315-3318 ◽  
Author(s):  
Jose A. Carrasco ◽  
Andrew Harvey ◽  
Damien Hanlon ◽  
Vicent Lloret ◽  
Dave McAteer ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Anion Exchange ◽  
Layered Double Hydroxides ◽  
Exchange Reactions ◽  
Liquid Phase Exfoliation ◽  
Double Hydroxides

Direct exfoliation of carbonate layered double hydroxides has been achieved by using a novel horn-probe sonic tip, avoiding the development of time-consuming anion-exchange reactions.

Synthesis of a novel layered double hydroxides [MgAl4(OH)12](Cl)2·2.4H2O and its anion-exchange properties

2011 ◽  
Vol 185 (2-3) ◽  
pp. 1435-1439 ◽  
Author(s):  
Ramesh Chitrakar ◽  
Yoji Makita ◽  
Akinari Sonoda ◽  
Takahiro Hirotsu
Keyword(s):  
Anion Exchange ◽  
Layered Double Hydroxides ◽  
Double Hydroxides ◽  
Exchange Properties

Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: anin situX-ray powder diffraction study

2010 ◽  
Vol 43 (3) ◽  
pp. 434-447 ◽  
Author(s):  
Rune E. Johnsen ◽  
Frank Krumeich ◽  
Poul Norby
Keyword(s):  
Phase Transformation ◽  
Exchange Reaction ◽  
Anion Exchange ◽  
Powder Diffraction ◽  
Layered Double Hydroxides ◽  
Two Phase ◽  
X Ray ◽  
Double Hydroxides ◽  
Anion Exchange Reaction

Anion-exchange processes in cobalt–aluminium layered double hydroxides (LDHs) were studied byin situsynchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl–CO3→ CoAl–Cl → CoAl–CO3, CoAl–Cl → CoAl–NO3and CoAl–CO3→ CoAl–SO4. The XRPD data show that the CoAl–CO3→ CoAl–Cl process is a two-phase transformation, where the amount of the CoAl–CO3phase decreases exponentially while that of the CoAl–Cl phase increases exponentially. Energy-dispersive X-ray spectroscopy (EDXS) studies of a partially chloride-exchanged CoAl–CO3LDH sample along within situXRPD data suggested that the individual particles in the CoAl–CO3sample are generally anion-exchanged with chloride one at a time. In contrast with the CoAl–CO3→ CoAl–Cl transformation, the XRPD data show that the reverse CoAl–Cl → CoAl–CO3process is a one-phase transformation. Rietveld refinements indicate that the occupancy factors of the carbon and oxygen sites of the carbonate group increase, while that of the chloride site decreases. In the CoAl–Cl → CoAl–NO3anion-exchange reaction, the XRPD patterns reveal the existence of two intermediate phases in addition to the initial CoAl–Cl and final CoAl–NO3phases. Thein situdata indicate that one of these intermediates is a mixed nitrate- and chloride-based LDH phase, where the disorder decreases as the nitrate content increases. The XRPD data of the partial CoAl–CO3→ CoAl–SO4anion-exchange reaction show that the process is a two-phase transformation involving a sulfate-containing LDH with a 1H polytype structure.

Use of layered double hydroxides to improve the triple phase boundary in anion-exchange membrane fuel cells

2010 ◽  
Vol 195 (19) ◽  
pp. 6500-6503 ◽  
Author(s):  
Kohei Miyazaki ◽  
Takeshi Abe ◽  
Koji Nishio ◽  
Haruyuki Nakanishi ◽  
Zempachi Ogumi
Keyword(s):  
Fuel Cells ◽  
Phase Boundary ◽  
Anion Exchange ◽  
Layered Double Hydroxides ◽  
Anion Exchange Membrane ◽  
Triple Phase Boundary ◽  
Double Hydroxides ◽  
Exchange Membrane

scholarly journals Water defluoridation by carbonate calcined and uncalcined Layered Double Hydroxides (LDHs)

2019 ◽  
Vol 98 ◽  
pp. 09005
Author(s):  
Elisabetta Dore ◽  
Franco Frau
Keyword(s):  
Anion Exchange ◽  
Sorption Capacity ◽  
Layered Double Hydroxides ◽  
Lamellar Structure ◽  
Ph Value ◽  
Molar Ratio ◽  
Fluoride Removal ◽  
Cationic Composition ◽  
Removal Capacity ◽  
Double Hydroxides

Carbonate Layered Double Hydroxides (LDHs) with different cationic composition and M2+/M3+ molar ratio were tested, both untreated and calcined, for water defluoridation. The defluoridation capacity of calcined LDHs, produced by intercalation during the reconstruction of lamellar structure, is more effective than the anion exchange of untreated LDHs. Among the calcined LDHs tested, that with 3Mg/(0.5Al+0.5Fe) molar ratio yields a maximum fluoride sorption capacity up to 92.3 mg/g, in spite of the high pH value (up to 12) of the experiments. After four cycles of regeneration by calcination and subsequent water defluoridation, this LDH composition maintains more than 80% of its fluoride removal capacity.

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