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.

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 Fluorescing Layered Double Hydroxides as Tracer Materials for Particle Injection during Subsurface Water Remediation

2020 ◽  
Vol 4 (3) ◽  
pp. 53
Author(s):  
Karen Maria Dietmann ◽  
Tobias Linke ◽  
Markus Reischer ◽  
Vicente Rives
Keyword(s):  
Layered Double Hydroxides ◽  
Chlorinated Solvents ◽  
Cost Effective ◽  
Water Remediation ◽  
Subsurface Water ◽  
Particle Injection ◽  
Global Issue ◽  
Cost Effective Method ◽  
Co Precipitation ◽  
Double Hydroxides

Nowadays, the contamination of groundwater and soils by highly hazardous and toxic chlorinated solvents is a global issue. Over the past years, different remediation strategies have been developed, involving injection of reactive solutions and/or particles. However, a major difficulty is the monitoring of injected particles during the injection and after secondary mobilisation by groundwater flow. This study is focussed on the development of directly traceable particles by combining fluorescein with Layered Double Hydroxides (LDHs). We present here the facile and easily tuneable synthesis of fluorescing LDHs (Fluo-LDH) via co-precipitation under supersaturation conditions. Their ability to mimic particle sizes of previously studied reactive LDHs, which proved to be able to adsorb or degrade chlorinated organic solvents from aqueous solutions, was investigated as well. Tests using a novel Optical Image Profiler (OIP) confirmed that the fluorescent LDHs can be easily detected with this tool. Even LDHs with the lowest amount of fluorescent dye were detectable. Together with the use of an OIP, which is capable of exciting the fluorescent material and collecting real-time pictures, this can provide a new, efficient, and cost-effective method for in situ tracing of injected particles in the subsurface.

scholarly journals Mixed Oxide Layered Double Hydroxide Materials: Synthesis, Characterization and Efficient Application for Mn2+ Removal from Synthetic Wastewater

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4089
Author(s):  
Cristina Modrogan ◽  
Simona Cǎprǎrescu ◽  
Annette Madelene Dǎncilǎ ◽  
Oanamari Daniela Orbuleț ◽  
Eugeniu Vasile ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Layered Double Hydroxides ◽  
Synthetic Wastewater ◽  
Precipitation Method ◽  
Metallic Ions ◽  
Materials Synthesis ◽  
Experimental Conditions ◽  
Edx Analysis ◽  
Co Precipitation ◽  
Double Hydroxides

Magnesium–aluminum (Mg-Al) and magnesium–aluminum–nickel (Mg-Al-Ni) layered double hydroxides (LDHs) were synthesized by the co-precipitation method. The adsorption process of Mn2+ from synthetic wastewater was investigated. Formation of the layered double hydroxides and adsorption of Mn2+ on both Mg-Al and Mg-Ni-Al LDHs were observed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDX) analysis. XRD patterns for prepared LDHs presented sharp and symmetrical peaks. SEM studies revealed that Mg-Al LDH and Mg-Al-Ni LDH exhibit a non-porous structure. EDX analysis showed that the prepared LDHs present uniformly spread elements. The adsorption equilibrium on these LDHs was investigated at different experimental conditions such as: Shaking time, initial Mn2+ concentration, and temperatures (10 and 20 °C). The parameters were controlled and optimized to remove the Mn2+ from synthetic wastewater. Adsorption isotherms of Mn2+ were fitted by Langmuir and Freundlich models. The obtained results indicated that the isotherm data fitted better into the Freundlich model than the Langmuir model. Adsorption capacity of Mn2+ gradually increased with temperature. The Langmuir constant (KL) value of Mg-Al LDH (0.9529 ± 0.007 L/mg) was higher than Mg-Al-Ni LDH (0.1819 ± 0.004 L/mg), at 20 °C. The final adsorption capacity was higher for Mg-Al LDH (91.85 ± 0.087%) in comparison with Mg-Al-Ni LDH (35.97 ± 0.093%), at 20 °C. It was found that the adsorption kinetics is best described by the pseudo-second-order model. The results indicated that LDHs can be considered as a potential material for adsorption of other metallic ions from wastewater.

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 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.

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