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.

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 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 Exploring the Wet Mechanochemical Synthesis of Mg-Al, Ca-Al, Zn-Al and Cu-Al Layered Double Hydroxides from Oxides, Hydroxides and Basic Carbonates

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 954 ◽  
Author(s):  
Brenda Antoinette Barnard ◽  
Frederick Johannes Willem Jacobus Labuschagné
Keyword(s):  
Mechanochemical Synthesis ◽  
Layered Double Hydroxides ◽  
Raw Materials ◽  
Green Method ◽  
Synthesis Conditions ◽  
Starting Point ◽  
Bead Mill ◽  
One Step ◽  
Synthesis Procedure ◽  
Double Hydroxides

The synthesis of Mg-Al, Ca-Al, Zn-Al and Cu-Al layered double hydroxides (LDHs) was investigated with a one-step wet mechanochemical route. The research aims to expand on the mechanochemical synthesis of LDH using a mill designed for wet grinding application. A 10% slurry of solids was added to a Netzsch LME 1 horizontal bead mill and milled for 1 h at 2000 rpm. Milling conditions were selected according to machine limitations and as an initial exploratory starting point. Precursor materials selected consisted of a mixture of oxides, hydroxides and basic carbonates. Samples obtained were divided such that half was filtered and dried at 60 °C for 12 h. The remaining half of the samples were further subjected to ageing at 80 °C for 24 h as a possible second step to the synthesis procedure. Synthesis conditions, such as selected precursor materials and the MII:MIII ratio, were adapted from existing mechanochemical methods. LDH synthesis prior to ageing was successful with precursor materials observably present within each sample. No Cu-Al LDH was clearly identifiable. Ageing of samples resulted in an increase in the conversion of raw materials to LDH product. The research offers a promising ‘green’ method for LDH synthesis without the production of environmentally harmful salt effluent. The synthesis technique warrants further exploration with potential for future commercial up-scaling.

scholarly journals Application of Zn/Al layered double hydroxides for the removal of nano-scale plastic debris from aqueous systems

2020 ◽  
Vol 397 ◽  
pp. 122769
Author(s):  
Ekta Tiwari ◽  
Nisha Singh ◽  
Nitin Khandelwal ◽  
Fazel Abdolahpur Monikh ◽  
Gopala Krishna Darbha
Keyword(s):  
Layered Double Hydroxides ◽  
Aqueous Systems ◽  
Plastic Debris ◽  
Nano Scale ◽  
Double Hydroxides

Activating room temperature phosphorescence by organic materials using synergistic effects

2019 ◽  
Vol 7 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Xianggui Kong ◽  
Xinrui Wang ◽  
Huimin Cheng ◽  
Yufei Zhao ◽  
Wenying Shi
Keyword(s):  
Layered Double Hydroxides ◽  
Chemical Bonding ◽  
Room Temperature ◽  
Design Principle ◽  
Synergistic Effects ◽  
Heavy Atom ◽  
Room Temperature Phosphorescence ◽  
Host Matrix ◽  
Double Hydroxides ◽  
Atom Effect

We present a design principle to activate highly efficient organic room temperature phosphorescent (ORTP) of carbon dots (CDs), with layered double hydroxides (LDHs) as the host matrix, that utilizes three synergistic effects,i.e.structural confinement effect, heavy atom effect, and chemical bonding.

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.

Sign in / Sign up

Export Citation Format

Share Document