Microwaves and layered double hydroxides: A smooth understanding

2009 ◽  
Vol 81 (8) ◽  
pp. 1459-1471 ◽  
Author(s):  
Patricia Benito ◽  
Francisco M. Labajos ◽  
Vicente Rives
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Particle Size Distribution ◽  
Hydrothermal Treatment ◽  
Layered Double Hydroxides ◽  
Urea Hydrolysis ◽  
Microwave Hydrothermal ◽  
Noticeable Reduction ◽  
Time Required ◽  
Double Hydroxides

Microwave-hydrothermal treatment (MWHT), a modification of conventional hydrothermal treatment, has been used during post-treatment of different layered double hydroxides (LDHs). In some cases, microwaves (MWs) have been used simultaneously with urea hydrolysis or for reconstruction of the LDH structure. The main advantages of replacing the conventional furnaces by MW ovens are a noticeable reduction in the time required to complete the process to obtain well-crystallized materials, and modification of their particle size distribution and textural and thermal properties. MW radiation leads to an increase in the rate of urea hydrolysis and consequently to fast precipitation of LDHs. Finally, the memory effect of Ni,Al-based LDHs is also improved.

scholarly journals Controlling the Synthesis Conditions for Tuning the Properties of Hydrotalcite-Like Materials at the Nano Scale

2018 ◽  
Vol 2 (3) ◽  
pp. 31 ◽  
Author(s):  
Raquel Trujillano ◽  
Inés González-García ◽  
Alvaro Morato ◽  
Vicente Rives
Keyword(s):  
Hydrothermal Treatment ◽  
Layered Double Hydroxides ◽  
Room Temperature ◽  
The Other ◽  
Synthesis Conditions ◽  
Nano Scale ◽  
Microwave Hydrothermal ◽  
Double Hydroxides

Three series of layered double hydroxides (LDH) with a hydrotalcite-like structure and composition corresponding to [Mg4Al2(OH)12(CO3)]·3H2O have been prepared from a common batch by applying three different aging procedures, namely, stirring at room temperature, hydrothermal treatment, and microwave-hydrothermal treatment. It has been found that the tested properties of the samples (mainly related to their crystallinity) are considerably improved by using the microwave-hydrothermal treatment. Shorter times are also evinced than in the other two aging treatments; however, if the microwave-hydrothermal treatment is too far extended, incipient destruction of the particles is observed.

Structural and thermal properties of polystyrene nanocomposites containing hydrophilic and hydrophobic layered double hydroxides

2013 ◽  
Vol 77-78 ◽  
pp. 46-51 ◽  
Author(s):  
Ahmed M. Youssef ◽  
Tamás Bujdosó ◽  
Viktória Hornok ◽  
Szilvia Papp ◽  
Abou el Fotouh Abdel Hakim ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Layered Double Hydroxides ◽  
Double Hydroxides

Co-Containing LDHs Synthesized by the Microwave-Hydrothermal Method

2006 ◽  
Vol 514-516 ◽  
pp. 1241-1245
Author(s):  
Patricia Benito ◽  
Maria Herrero ◽  
Francisco Martin Labajos ◽  
Vicente Rives
Keyword(s):  
Oxidation State ◽  
Layered Double Hydroxides ◽  
Treatment Time ◽  
Synthesis And Characterization ◽  
Thermal Treatments ◽  
Microwave Hydrothermal ◽  
Microwave Hydrothermal Method ◽  
Divalent Cobalt ◽  
Double Hydroxides

The synthesis and characterization of Co,Al Layered Double Hydroxides (LDHs) containing carbonate is reported. The solids have been submitted to several thermal treatments, hydrothermal and microwave-hydrothermal, modifying both the treatment time and temperature, with the main aim of studying their influence on the crystallinity of the solids and on the stabilization of divalent cobalt oxidation state. The results show that whichever the temperature and time used the only phase detected was the hydrotalcite, and that the cobalt cations keep the divalent oxidation state.

Morphology and thermal properties relationship in poly(p-dioxanone)/layered double hydroxides nanocomposites

2010 ◽  
Vol 288 (7) ◽  
pp. 809-818 ◽  
Author(s):  
Manuela Zubitur ◽  
Agurtzane Mugica ◽  
Javier Areizaga ◽  
Milagros Cortázar
Keyword(s):  
Thermal Properties ◽  
Layered Double Hydroxides ◽  
Double Hydroxides

Effect of Layered Double Hydroxides with Different Particle Size on Properties of Bitumen

2018 ◽  
Vol 913 ◽  
pp. 1062-1069
Author(s):  
Min Wu ◽  
Lian Li ◽  
Bian Yang He ◽  
Jian Ying Yu
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Rheological Properties ◽  
Layered Double Hydroxides ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Uv Aging ◽  
Aging Resistance ◽  
Microscopic Morphology ◽  
Double Hydroxides

The crystal structure, microscopic morphology, particle size distribution and UV shielding properties of layered double hydroxides (LDHs) with different particle size were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser particle size analysis and ultraviolet and visible (UV-vis) spectrophotometer. The effects of LDHs with different particle size on the physical, rheological properties and UV aging resistance of bitumen were investigated by conventional physical properties and dynamic rheological characteristics. The results indicated that the particle size of LDHs had a little effect on the physical properties, and it had some influence on rheological properties of bitumen, but its influence on the UV aging resistance of bitumen was different significantly. When UV aging time was 9d, the viscosity aging indexes of bitumen modified by LDHs with different particle size (80nm, 115nm and 180nm) decreased by 48.2%, 58.1% and 63.8% compared with the pristine bitumen, respectively. LDHs with the particle size of 180 nm showed better improvement than other two kinds of LDHs on UV aging resistance of bitumen.

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