scholarly journals Effect of the Synthesis Method on the Phase Composition and Magnetism of Layered Double Hydroxides

2020 ◽  
Vol 56 (7) ◽  
pp. 747-753
Author(s):  
O. V. Nestroinia ◽  
I. G. Ryl’tsova ◽  
M. N. Yapryntsev ◽  
O. E. Lebedeva
Keyword(s):  
Phase Composition ◽  
Layered Double Hydroxides ◽  
Synthesis Method ◽  
Double Hydroxides

scholarly journals Effect of Synthesis Method on Properties of Layered Double Hydroxides Containing Ni(III)

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1429
Author(s):  
Olga V. Nestroinaia ◽  
Irina G. Ryltsova ◽  
Olga E. Lebedeva
Keyword(s):  
Phase Composition ◽  
Oxidation State ◽  
Layered Double Hydroxides ◽  
Synthesis Method ◽  
Microwave Treatment ◽  
Thermal Transformations ◽  
Chemical Methods ◽  
Wet Chemical ◽  
Co Precipitation ◽  
Double Hydroxides

Unstable oxidation state +3 of nickel can be stabilized in the structure of layered double hydroxides, the resulting crystallinity and properties being dependent on the synthesis method. Three different wet chemical methods (co-precipitation at variable pH, co-precipitation followed by hydrothermal treatment, co-precipitation with microwave treatment) were used to synthesize Mg/Ni–Al layered double hydroxides containing triply charged nickel cations. Lattice parameters of the samples synthesized by various methods were found to differ from each other by about 1.5%. The most crystallized sample was obtained by hydrothermal synthesis. The oxidation state of nickel in the LDH samples was confirmed by XPS. TEM mapping gave evidence of the uniform distribution of nickel in all the samples. The LDHs’ reduction with hydrogen and thermal transformations of the phase composition and morphology of LDHs were studied in detail. The properties of the samples synthesized by the different methods were shown to be quite similar.

Effect of synthesis method on selective adsorption of thiosulfate by calcined MgAl-layered double hydroxides

2013 ◽  
Vol 232 ◽  
pp. 510-518 ◽  
Author(s):  
Cuiyu Geng ◽  
Tianhao Xu ◽  
Yaping Li ◽  
Zheng Chang ◽  
Xiaoming Sun ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Selective Adsorption ◽  
Synthesis Method ◽  
Double Hydroxides

scholarly journals Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

2020 ◽  
Author(s):  
Bianca Gevers ◽  
Sajid Naseem ◽  
Charles Sheppard ◽  
Andreas Leuteritz ◽  
Johan Labuschagne
Keyword(s):  
Transition Metals ◽  
Absorption Spectra ◽  
Layered Double Hydroxides ◽  
Synthesis Method ◽  
Adequate Explanation ◽  
Standard Methods ◽  
Absorption Intensity ◽  
Synthesis Conditions ◽  
Nir Absorption ◽  
Double Hydroxides

<div>Layered double hydroxides (LDHs) with high and tailorable UV-Vis-NIR absorption were prepared through transition</div><div>metal (TM) modification. The synthesis method used and amount of TM present were found to influence the UV-Vis-</div><div>NIR absorption intensity, -range, and the optical bandgap.</div><div><div>It was found that the incorporation of TMs in MgAl-LDH results in the existence of a "UV-Vis-NIR absorption fingerprint", the intensity of which can be tuned by the amount of TM present. There also exist differences in the UV-Vis-NIR absorption spectra and bandgaps obtained for MgAl-LDH synthesised using different synthesis conditions and methods, but these are not as visible when including transition metals. Further, the materials exhibit very complex spectra for which adequate explanation is lacking in literature. Finally, standard methods to determine the bandgap of materials, did not give conclusive results for all materials, only for some, and indicate that some of the materials might have multiple different transition types.</div></div>

scholarly journals Continuous Synthesis of Doped Layered Double Hydroxides in a Meso-Scale Flow Reactor

2018 ◽  
Author(s):  
Polina Yaseneva ◽  
Nan An ◽  
Matt Finn ◽  
Nicholas Tidemann ◽  
Nicholas Jose ◽  
...  
Keyword(s):  
Particle Size ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Layered Double Hydroxides ◽  
Flow Reactor ◽  
Synthesis Method ◽  
Material Stability ◽  
Double Hydroxides ◽  
Meso Scale

Detailed characterisation of morphology of doped hydrotalcites as catalysts precursors. Trends of material stability, pore size distribution, particle size as a function of the nature of dopants. Data on the flow synthesis method and reproducibility of materials that can be attained by this method.

scholarly journals Continuous Synthesis of Doped Layered Double Hydroxides in a Meso-Scale Flow Reactor

2018 ◽  
Author(s):  
Polina Yaseneva ◽  
Nan An ◽  
Matt Finn ◽  
Nicholas Tidemann ◽  
Nicholas Jose ◽  
...  
Keyword(s):  
Particle Size ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Layered Double Hydroxides ◽  
Flow Reactor ◽  
Synthesis Method ◽  
Material Stability ◽  
Double Hydroxides ◽  
Meso Scale

Detailed characterisation of morphology of doped hydrotalcites as catalysts precursors. Trends of material stability, pore size distribution, particle size as a function of the nature of dopants. Data on the flow synthesis method and reproducibility of materials that can be attained by this method.

scholarly journals Decontamination of Arsenic in Actual Water Samples by Calcium Containing Layered Double Hydroxides from a Convenient Synthesis Method

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1150 ◽  
Author(s):  
Hongtao Lu ◽  
Shuxia Liu ◽  
Hua Zhang ◽  
Yanling Qiu ◽  
Jianfu Zhao ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Water Samples ◽  
Arsenic Concentration ◽  
Synthesis Method ◽  
Mining Area ◽  
Hunan Province ◽  
World Health ◽  
Maximum Adsorption Capacity ◽  
Batch Tests ◽  
Double Hydroxides

A series of calcium-containing layered double hydroxides (LDHs) and calcined product (CLDH) were synthesized using a comparative simple synthesis method (without using organic solvents and with a shortened reaction time) and applied in the adsorption of arsenic in water. The adsorption performance of arsenate on these LDHs and CLDH were studied using batch tests. The effects of various factors during the adsorption process, such as pH of the solution, dosage of materials, coexisting ions, contact time, and initial arsenate concentration, were evaluated. The maximum adsorption capacity of arsenate on three materials (CaFe-CLDH, CaFe-Cl-LDH, CaFe-NO3-LDH) were 156.0 mg·g−1, 150.5 mg·g−1, and 148.0 mg·g−1, respectively. When the concentration of CaFe-CLDH was 0.5 g·L−1, the concentration of arsenate was reduced from 5000 μg·L−1 to 10 μg·L−1 after adsorption. Moreover, when the CaFe-NO3-LDH or CaFe-Cl-LDH dosage was 1.0 g·L−1, a similar decontamination result could be achieved. The synthesized CaFe-CLDH was used to treat actual contaminated water samples from a river in a mining area north of Lengshuijiang City in Hunan Province, China. After treating using CaFe-CLDH, the residual arsenic concentration of actual water samples can fully meet the requirements for arsenic in the drinking water standards of the World Health Organization and China. This indicates that synthetic CaFe-CLDH has the potential to serve as an effective adsorbent for the removal of arsenic contamination.

scholarly journals Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

2020 ◽  
Author(s):  
Bianca Gevers ◽  
Sajid Naseem ◽  
Charles Sheppard ◽  
Andreas Leuteritz ◽  
Johan Labuschagne
Keyword(s):  
Transition Metals ◽  
Absorption Spectra ◽  
Layered Double Hydroxides ◽  
Synthesis Method ◽  
Adequate Explanation ◽  
Standard Methods ◽  
Absorption Intensity ◽  
Synthesis Conditions ◽  
Nir Absorption ◽  
Double Hydroxides

<div>Layered double hydroxides (LDHs) with high and tailorable UV-Vis-NIR absorption were prepared through transition</div><div>metal (TM) modification. The synthesis method used and amount of TM present were found to influence the UV-Vis-</div><div>NIR absorption intensity, -range, and the optical bandgap.</div><div><div>It was found that the incorporation of TMs in MgAl-LDH results in the existence of a "UV-Vis-NIR absorption fingerprint", the intensity of which can be tuned by the amount of TM present. There also exist differences in the UV-Vis-NIR absorption spectra and bandgaps obtained for MgAl-LDH synthesised using different synthesis conditions and methods, but these are not as visible when including transition metals. Further, the materials exhibit very complex spectra for which adequate explanation is lacking in literature. Finally, standard methods to determine the bandgap of materials, did not give conclusive results for all materials, only for some, and indicate that some of the materials might have multiple different transition types.</div></div>

Layered Double Hydroxides (LDHs) Type Materials Used in Water Treatment

2015 ◽  
Vol 660 ◽  
pp. 273-278 ◽  
Author(s):  
Simona Nichitus ◽  
Gabriela Calin ◽  
Alexandra Burlui ◽  
Carmen Stadoleanu ◽  
Vasile Burlui
Keyword(s):  
Water Treatment ◽  
Layered Double Hydroxides ◽  
Mixed Oxides ◽  
Waste Water Treatment ◽  
Sol Gel ◽  
Synthesis Method ◽  
Cost Effective ◽  
Thermally Activated ◽  
Materials Used ◽  
Double Hydroxides

Layered double hydroxides (LDHs) or LDHs matrices used for water treatment have been reviewed in this article. These aggregated nanoparticles can be obtained by sol-gel, hydrothermal or coprecipitation method, therefore their shape, size, properties (such as magnetic, acido-bazic, red-ox, texture and assembly) and applications are tailored as a function of synthesis method and process parameters respectively. Among other materials used in water treatment we chose layered double hydroxides generally named LDHs or in particular case hydrotalcites (MgAlLDHs). During calcination layered structure is destroyed giving rise to new structures like mixed oxides partially crystallized. LDHs and calcined LDHs type materials were able to uptake selected products. An important issue for removal of undesirable species for human health was M2+/M3+ cation ratio. Results show a better uptake of anionic compounds for thermally activated LDHs due to their “memory effect”. A large variety of LDHs was investigated in order to demonstrate their adsorption capacity for anionic compounds, cations, gas compounds even microorganisms. Nowadays one of the atractive issues of nanoscience is both the synthesis of these nanostructures and the assembly and organization way but the interest of scientists is to find new properties and applications in order to protect the environment. These cost effective, eco-friendly materials revealed new opportunities for waste water treatment.

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