Synthesis and Properties of Terephthalate and Benzoate Intercalates of Mg−Al Layered Double Hydroxides Possessing Varying Layer Charge

1996 ◽  
Vol 8 (8) ◽  
pp. 1969-1977 ◽  
Author(s):  
Fathi Kooli ◽  
Ian C. Chisem ◽  
Masha Vucelic ◽  
William Jones
Keyword(s):  
Layered Double Hydroxides ◽  
Layer Charge ◽  
Double Hydroxides

scholarly journals Fumonisin B1 Interaction with Mg-Al and Mg-Fe Layered Double Hydroxides: Removal Efficiency and Mechanisms

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4344
Author(s):  
Jakub Matusik ◽  
Youjun Deng
Keyword(s):  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Layered Double Hydroxides ◽  
Lower Layer ◽  
Fumonisin B1 ◽  
Xrd Analysis ◽  
Layer Charge ◽  
Basal Spacing ◽  
Co Precipitation ◽  
Double Hydroxides

Mycotoxins in feed and food are highly toxic and pose a serious danger even at very low concentrations. The use of bentonites in animal diet can reduce toxin bioavailability. However, some mycotoxins like fumonisin B1 (FB1) form anionic species which excludes the use of negatively charged clays. Layered double hydroxides (LDH) with anion-exchange properties, in theory, can be perfect candidates to adsorb FB1. However, fundamental research on the use of LDH for mycotoxins removal is scarce and incomplete. Thus, the presented study was designed to explore such a possibility. The LDH materials with differing chemistry and layer charge were synthesized by co-precipitation both from metal nitrates and chlorides and were then tested for FB1 removal. XRD, FTIR, XPS, and chemical analysis were used for the LDH characterization and to obtain insight into the removal mechanisms. A higher adsorption capacity was observed for the Mg/Al LDH samples (~0.08–0.15 mol/kg) in comparison to the Mg/Fe LDH samples (~0.05–0.09 mol/kg) with no difference in removal efficiency between Cl and NO3 intercalated LDH. The adsorption capacity increased along with lower layer charge of Mg/Al and was attributed to the lower content of bonded carbonates and the increase of non-polar sites which led to matching between the adsorption domains of LDH with FB1. The FTIR analysis confirmed the negative effect of carbonates which hampered the adsorption at pH 7 and led to the highest adsorption at pH 5 (FB1 content ~15.8 ± 0.75 wt.%). The fast surface adsorption (1–2 min) was dominant and XRD analysis of the basal spacing indicated that no FB1 intercalation occurred in the LDH. The XPS confirmed a strong interaction of FB1 with Mg sites of LDH at pH 5 where the interaction with FB1 carboxylate moieties COO− was confirmed. The research confirmed a high affinity and selectivity of LDH structures towards anionic forms of FB1 mycotoxin.

scholarly journals Preparation of MgGa Layered Double Hydroxides and Possible Compositional Variation

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1206
Author(s):  
Rattanawadee (Ploy) Wijitwongwan ◽  
Soontaree (Grace) Intasa-ard ◽  
Makoto Ogawa
Keyword(s):  
Charge Density ◽  
Layered Double Hydroxides ◽  
Lower Layer ◽  
Sodium Dodecyl ◽  
Morphological Characteristics ◽  
Lattice Parameter ◽  
Layer Charge ◽  
Compositional Variation ◽  
Dodecyl Sulfate ◽  
Double Hydroxides

Layered double hydroxides (LDHs), shown as the general formula of [M2+1−xM3+x(OH)2]x+(An−)x/n∙yH2O, are useful for various applications such as anion exchangers/adsorbents, catalysts and catalysts’ supports, and drug/gene carriers due to their structural, compositional and morphological characteristics and their variation. The x value (M3+/(M2+ + M3+) ratio) in layered double hydroxides (LDHs), corresponding to the layer charge density, is one of the important parameters for controlling the properties of LDHs. The x values in commonly available LDHs are limited (0.2 < x < 0.3). In order to obtain LDHs with x < 0.2, Mg2+ Ga3+–LDHs with interlayer iodide were examined. The linear correlation between lattice parameter a and x value in the products with x of 0.06–0.24 was seen, suggesting the successful substitution of Mg2+ in the brucite-like sheet with Ga3+. Carbonate and dodecyl sulfate types MgGa–LDH were prepared by ion exchange with carbonate anion and reconstruction in aqueous solution of sodium dodecyl sulfate. The products with x of 0.06 were dispersed in water and hexanol better than those with x of 0.24 for MgGa–LDHs containing carbonate and dodecyl sulfate, respectively, suggesting effects of the lower layer charge density on the dispersion.

Effect of layer charge modification for CoAl layered double hydroxides: study by X-ray absorption spectroscopy

2001 ◽  
Vol 3 (1-2) ◽  
pp. 81-92 ◽  
Author(s):  
Fabrice Leroux ◽  
El Mostafa Moujahid ◽  
Christine Taviot-Guého ◽  
Jean-Pierre Besse
Keyword(s):  
Absorption Spectroscopy ◽  
Layered Double Hydroxides ◽  
Layer Charge ◽  
X Ray ◽  
Double Hydroxides ◽  
X Ray Absorption

Pillaring of Layered Double Hydroxides Possessing Variable Layer Charge with Vanadium Polyoxoanions

1994 ◽  
Vol 371 ◽  
Author(s):  
F. Kooli ◽  
V. Rives ◽  
M.A. Ulibarri ◽  
W. Jones
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxides ◽  
Layer Charge ◽  
Second Phase ◽  
Textural Characteristics ◽  
Al Content ◽  
Complete Exchange ◽  
Double Hydroxides ◽  
Charge Balancing ◽  
Variable Layer

AbstractA range of layered double hydroxides (LDHs) with Ni/Al and Mg/Al as the M(II)/M(III) cations and containing carbonate as the charge balancing anion have been synthesised. A variation in the M(II)/M(III) ratio between 2 and 6 has been attempted with the influence of the M(II)/M(III) ratio upon the subsequent exchange of carbonate by [V10O28]6- (at pH 4.5) examined. Complete exchange is obtained for all ratios, although the crystallinity of the products varies. For M(II)/M(III) ratios > 4, the product crystallinity is poor. In addition, a second phase is detected for all ratios. In the case of Ni/Al, the amount of vanadium incorporated is found to depend upon the Al content whereas for Mg/Al the amount incorporated is constant. Overall, the replacement of carbonate by decavanadate does not appear to have any significant effect on the textural characteristics (e.g. surface area or porosity) of the pillared products.

Acceptorless amine dehydrogenation and transamination using Pd-doped layered double hydroxides

2018 ◽  
Author(s):  
Diana Ainembabazi ◽  
Nan An ◽  
Jinesh Manayil ◽  
Kare Wilson ◽  
Adam Lee ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Oxidation States ◽  
Secondary Amines ◽  
Primary Amines ◽  
Acid Dissolution ◽  
Oxidative Amination ◽  
Strong Function ◽  
Excellent Activity ◽  
High Yields ◽  
Double Hydroxides

<div> <p>The synthesis, characterization, and activity of Pd-doped layered double hydroxides (Pd-LDHs) for for acceptorless amine dehydrogenation is reported. These multifunctional catalysts comprise Brønsted basic and Lewis acidic surface sites that stabilize Pd species in 0, 2+, and 4+ oxidation states. Pd speciation and corresponding cataytic performance is a strong function of metal loading. Excellent activity is observed for the oxidative transamination of primary amines and acceptorless dehydrogenation of secondary amines to secondary imines using a low Pd loading (0.5 mol%), without the need for oxidants. N-heterocycles, such as indoline, 1,2,3,4-tetrahydroquinoline, and piperidine, are dehydrogenated to the corresponding aromatics with high yields. The relative yields of secondary imines are proportional to the calculated free energy of reaction, while yields for oxidative amination correlate with the electrophilicity of primary imine intermediates. Reversible amine dehydrogenation and imine hydrogenation determine the relative imine:amine selectivity. Poisoning tests evidence that Pd-LDHs operate heterogeneously, with negligible metal leaching; catalysts can be regenerated by acid dissolution and re-precipitation.</p> </div> <br>

Antibiotic-anionic Clay Matrix Used for Drug Controlled Release

2018 ◽  
Vol 69 (2) ◽  
pp. 321-323
Author(s):  
Georgeta Zegan ◽  
Elena Mihaela Carausu ◽  
Loredana Golovcencu ◽  
Alina Sodor Botezatu ◽  
Eduard Radu Cernei ◽  
...  
Keyword(s):  
Controlled Release ◽  
Layered Double Hydroxides ◽  
Bioactive Molecules ◽  
Drug Controlled Release ◽  
Anionic Clays ◽  
Anionic Clay ◽  
Toxicological Studies ◽  
High Efficient ◽  
Clay Matrix ◽  
Double Hydroxides

Anionic clay matrix acting as drug controlled release system have shown in last years a great potential for delivery of bioactive molecules and chemical therapeutics. This organic-inorganic nanohybrid system is high efficient offering an excellent protection of intercalated compounds from degradation. Compared to other nanoparticles used in medical area, anionic clays type layered double hydroxides have found to be biocompatible according to toxicological studies. Ampicillin containing MgAlLDHs and ZnAlLDH samples have been prepared following two routes: anion-exchange procedure and reconstruction from calcined layered double hydroxides. Solid samples have been characterized by FTIR and SEM-EDX highlighting the alteration of pristine LDHs structure when the antibiotic is introduced in the interlayer gallery.

Sign in / Sign up

Export Citation Format

Share Document