• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.725-727
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• 2012

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3488-3490
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• 2013

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.822-827
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• 2017

Mg/Al layered double hydroxide with two-dimensional (2D) nanostructures was synthesized by a hydrothermal technique. The morphology and aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ were controlled by the concentration and kinds of the hydrolysis agent, and temperature. The aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the 2D hexagonal crystal structure was tailored from about 12.6 to about 45.7. The intercalated $CO{_3}^{2-}$ anions of the synthesized 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides were exchanged to $NO_3{^-}$ anions. The bulk 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the increased space between two layers due to the anion exchange were exfoliated in a formamide solution. The aspect ratio of the exfoliated 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides increased to 570.3.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.107-108
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• 2015

Layered Double Hydroxides is known as a hydrotalcite-like material. It is a type of anionic clay with planar structure. It is composed of layer structure which is able to exchange anion between two layers which includes divalent ion and trivalent ion. Therefore, layered double hydroxide is applicable for eliminating harmful heavy metals and anionic substances which exist in the concrete. Because it is also able to be used as catalyst and has high possibility of utilization, It is getting an large amount of attention recently. In this study, an analysis on the structure of the layerd double hydroxide (LDH) which is possible to bind the anion was carried out.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1817-1824
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• 2014

The adsorption characteristics of chromium (VI) and phosphate on calcined Mg-Al-$CO_3$ layered double hydroxides (CLDH) were investigated in single and binary systems. A series of batch experiments were performed to study the influence of various experimental parameters. In this study, CLDH exhibited a high adsorption capacity for Cr (VI) and P in a single system. The experimental data were close to the theoretical adsorption capacity given by the Langmuir isotherm, the calculating adsorption capacities of Cr (VI) and P were up to 70.42 mg/g and 97.09 mg/g, respectively. It was found that the initial pH was approximately 6 and it took 24 h to reach equilibrium when P and Cr (VI) were added simultaneously. The experimental data were best fitted by a pseudo-second-order kinetics model. Competitive adsorption between Cr (VI) and P existed in the binary system. The presence of Cr (VI) had no significant influence on P adsorption. However, the suppression of Cr (VI) adsorption was obvious when the initial concentration of P was up to 10 mg/L with a concentration of 0.5 g/L of CLDH.

• Korean Journal of Materials Research
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• v.27 no.3
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• pp.161-165
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• 2017

In this paper, synthesis of terephthalate intercalated Zn-Al: Layered double hydroxides (LDHs) was studied. We designed freestanding Zn-Al: carbonate LDH nanosheets for a facile exchange technique. The as-prepared Zn-Al carbonate LDHs were converted to terephthalate intercalated Zn-Al:LDHs by ion exchange method. Initially, Al-doped ZnO (AZO) thin films were deposited on p-Si (001) by facing target sputtering. For synthesis of free standing carbonate Zn-Al:LDH, we dipped the AZO thin film in naturally carbonated water for 3 hours. Further, Zn-Al: carbonate LDH nanosheets were immersed in terepthalic acid (TA) solution. The ion exchange phenomena in the terephthalate assisted Zn-Al:LDH were confirmed using FT-IR analysis. The crystal structure of terephthalate intercalated Zn-Al:LDH was investigated by XRD pattern analysis with different mole concentrations of TA solution and reaction times. The optimal conditions for intercalation of terephthalate from carbonated Zn-Al LDH were established using 0.3 M aqueous solution of TA for 24 hours.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.443-450
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• 1998

Layered double hydroxides(LDHs) [{{{{ {Mg }_{1-x } }}{{{{ {Al }_{x } }}({{{{ {OH}_{2 } }})]ζ+({{{{ {CO }`_{3 } ^{2- } ){ }_{x/2 } }}$.${{{{ { yH}_{2 }O }} wioth variation of layer charge densitywere synthesized by co-precipitation methdo since their charge densities have a very important role to be det-ermined the physicochemical properties of layered materials. The XRD IR and thermal studies of them were discussed and the kinetic study for the decarbonation reaction was also carried out. From the results of XRD analysis we found that the lattice parameter and the unit cell volume were linearly decreased with the amount of Al substituents(x) in the vicinity of x=2∼10${\times}$1/3${\times}$10-1 but they had nearly constant values when the x are far from these vicinit. The activation energies for the decarbonation reaction of x=6.8, 10${\times}$1/3${\times}${{{{ { 10}^{-1 } }} were estimated to be 47.0, 37.6, 39.3 kcal/mol The specific surface areas(90-120 m2/g) of stable hy-drotalcite-type LDHs were dractically decreased with increasing of layer charge density.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.248-252
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• 2005

Synthetic layered double hydroxides (LDHs), [$Mg_4Al_2(OH)_{12}]CO_3{\cdot}nH_2O$, were prepared in the submicron size of plate-like polycrystals. Anion-exchange reactions with various linear dicarboxylic acids were performed to produce LDH/organic hybrid materials by solvothermal treatment in toluene. X-ray powder diffraction spectra for the products indicated that the interlayer spacings of LDHs remarkably changed, up to 20 $\AA$ when 1,10-decanedicarboxylic acid anions were intercalated as an organic guest. Dicarboxylates-LDHs samples could be also re-exchanged consecutively with other dicarboxylic acids or carbonate without serious destruction of layer structure under the scanning electron microscopic observation.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.670-675
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• 2008

Batch type adsorption and desorption tests were performed with different types (Powder, Granule) of Layered double hydroxides (LDHs) saturated with phosphate. The adsorption isotherm was approximated as a modified Langmuir type equation. The maximum adsorption capacity was 55 mg-P/g-LDH for powder type LDH, and 46 mg-P/g-LDH for granule type LDH. The highest phosphate desorption (79.6%) was obtained with 20% NaOH solution, whereas the desorption degrees were 4.8, 22.2% and 46.7% in the solutions of acidic condition (pH 4), 30% NaCl, and 3% NaOH, respectively. It was suggested that the optimal condition for the phosphate desorption from LDH was 30% NaCl + 3~6% NaOH solutions. The desorption characteristics of LDH was little influenced by adsorbent type.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.165-166
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• 2017