• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.412-417
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• 2007

This study was to elucidate the effects of layered double hydroxides(LDHs) application on the chemical properties of the soils along with the fate of the applied LDHs. The effects of LDHs application were compared with those of calcium carbonate widely used for the neutralization of acidic soils. Incorporation of LDHs into the soil resulted in higher pH value and $Mg^{2+}$ content in soil leachate than that of $CaCO_3$ treatment. There was no significant difference in water-soluble P content in both the treatments. However, $Al^{3+}$ and $Si^{4+}$ contents were decreased by LDHs and $CaCO_3$ treatment, even though a large amount of $Al^{3+}$ was released into soil solution with the disintegration of LDHs framework. LDHs structure in soil was gradually disintegrated from the its original layered structure under acidic condition of soil. Therefore, this study suggests that LDHs could be utilized as a carrier of functional substances to enhance the efficiency of various ago-chemicals without any ill effects on the soil environments.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.1019-1022
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• 2001

Negatively charged functional organic molecules such as retinoic acid, ascorbic acid, indole acetic acid, citric acid, salicylic acid, acidic dye (indigo carmine, Food Blue 1) are intercalatively encapsulated by zinc basic salt (hydrozincite) and layered double hydroxide. Such functional organic-inorganic nanohybrids are realized via coprecipitation reaction involving simultaneous formation of layered inorganic lattice and intercalation of anionic species. The heterostructural nature of these nanohybrids, their particle morphology and textural characterizations are mainly discussed on the basis of Powder X-ray Diffraction and Field Emission Scanning Electron Microscopy results.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.601-607
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• 2012

An aspect of organophilic modification for the delamination is described for the layered rare-earth hydroxides in this paper. The interlayer property of $RE_2(OH)_5NO_3{\cdot}nH_2O$, where RE=Eu (LEuH) and Tb (LTbH), was modified by the exchange reaction of nitrate ion with oleate anion that is one of the representative dispersion agents in nonpolar solvents. The bilayer arrangement of long oleate anions in the gallery of $RE_2(OH)_5NO_3{\cdot}nH_2O$ could effectively weaken the stacking of the hydroxide layers. Highly organophilic environment of the interlayer space promoted the introduction of toluene to delaminate the layered structure into their individual sheets. When irradiated with 365 nm UV, the resulting transparent colloidal solutions of toluene containing LEuH and LTbH nanosheets yielded typical red and green emissions, respectively, which are visible to the naked eye.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.248-248
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• 2003

층상이중수화물(Layered Double Hydroxides, LDH)은 층 사이에 무기물 음이온이 있는 2차원 충상구조물로서 이들 층 사이의 공간에 이동 가능한 수화된 음이온의 존재로 전하균형을 이룬다. 층 사이의 음이온은 교환이 가능하며, 나머지의 공간은 물분자로 채워져 있다. 이러한 특성을 응용하여 LDH는 촉매, 음이온 교환제, 흡착제, 담체로 사용가능하며, 특히 음이온 교환능이 있는 소재로 고분자에 적용되고 있으며, 층간에 염료를 삽입한 복합체의 제조 둥에 관한 연구가 활발히 이루어지고 있다. 이의 적용에서 LDH의 입도는 결정적인 한계 요인으로 작용하기도 한다. 본 실험에서는 Mg-Al-NO$_3$ 층상이중수산화물(Mg-Al-NO$_3$-LDH)을 공침전법으로 합성하고, 양이온의 농도와 공침시 pH 및 교반조건의 변화가 생성된 LDH의 결정상, 형상, 입도, 및 양이온교환능에 미치는 영향을 알아보았다. 특히 초음파 분산법을 적용하는 경우 생성되는 LDH 입자크기의 미세화에 효과적인 것을 확인 할 수 있었다.

• Environmental Engineering Research
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• v.15 no.3
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• pp.149-156
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• 2010

The objective of this study was to investigate microbial removal using layered double hydroxides (LDHs) and iron (hydr)oxides (IHs) immobilized onto granular media. Column experiments were performed using calcium alginate beads (CA beads), LDHs entrapped in CA beads (LDH beads), quartz sand (QS), iron hydroxide-coated sand (IHCS) and hematite-coated sand (HCS). Microbial breakthrough curves were obtained by monitoring the effluent, with the percentage of microbial removal and collector efficiency then quantified from these curves. The results showed that the LDH beads were ineffective for the removal of the negatively-charged microbes (27.7% at 1 mM solution), even though the positively-charged LDHs were contained on the beads. The above could be related to the immobilization method, where LDH powders were immobilized inside CA beads with nano-sized pores (about 10 nm); therefore, micro-sized microbes (E. coli = 1.21 ${\mu}m$) could not diffuse through the pores to come into contact with the LDHs in the beads, but adhere only to the exterior surface of the beads via polymeric interaction. IHCS was the most effective in the microbial removal (86.0% at 1 mM solution), which could be attributed to the iron hydroxide coated onto the exterior surface of QS had a positive surface charge and, therefore, effectively attracted the negatively-charged microbes via electrostatic interactions. Meanwhile, HCS was far less effective (35.6% at 1 mM solution) than IHCS because the hematite coated onto the external surface of QS is a crystallized iron oxide with a negative surface charge. This study has helped to improve our knowledge on the potential application of functional granular media for microbial removal.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2519-2521
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• 2013

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1032-1036
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• 1998

Intercalation compounds of organic anions into layered double hydroxides (LDH) are synthesized by the coprecipitation route. X-ray diffraction data reveal that the intercalated terephthalate (TP), naphthalene-2,6-disulfonate (NA26), and anthraquinone-2,6-disulfonate (AQ26) are arranged with their molecular planes perpendicular to the hydroxide layer. HPLC data show that 26.2% of TP and 73.8% of AQ26 are cointercalated, whereas NA26 is not intercalated into the Zn/Al-LDH. These results indicate the possibility of a molecular recognition ability of Zn/Al-LDH. The molecular recognition ability of intercalation into Zn/Al-LDH is in the order AQ26 > TP >> NA26.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.445-454
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• 2019

Layered double hydroxides (LDHs) nanoparticles have emerged as novel nanomaterials for bio-imaging applications due to its unique layered structure, physicochemical properties, and good biocompatibility. Bio-imaging is one of the most important fields for medical applications in clinical diagnostics and therapeutics of various diseases. Enhanced diagnostic techniques are needed to realize new paradigm for next-generation personalized medicine through nanoscale materials. When nanotechnology is introduced into bio-imaging system, nanoparticle probes can endow imaging techniques with enhanced ability to obtain information about biological system at the molecular level. In this review, we summarize structural features of LDH nanoparticles with current issues of bio-imaging system. LDH nanoparticle probes are also discussed through in vitro as well as in vivo studies in various bio-imaging techniques including fluorescence imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), and computed X-ray tomography (CT), which will have the potential in the development of the advanced nanoparticles with high sensitivity and selectivity.

• Proceedings of the Materials Research Society of Korea Conference
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• 2004.05a
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• pp.41-41
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• 2004

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.36-41
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• 1998

Intercalation compounds of alkyl sulfonates into layered double hydroxides (LDH) have been directly synthesized. From the X-ray diffraction data and the alkyl sulfonates size, the orientation of the intercalated alkyl sulfonate into the layered double hydroxide was determined. The intercalated alkyl sulfonate is arranged with molecular chain perpendicular to the hydroxide layer with an antiparallel pattern.