• 한국물환경학회지
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• 제22권6호
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• pp.991-995
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• 2006

The layered double hydroxide with the insertion of chloride ions (LDH-Cl), which was synthesized by the co-precipitation method, was applied to investigate the fundamental aspects of the absorptive agent for phosphate removal from wastewater. The adsorption capacity was best described by the Langmuir-FreundIich isotherm, and the estimated isotherm parameters indicate that the LDH-CI capacity for the phosphate removal is much higher than that observed using a natural adsorbent material such iron oxide tailing. The kinetic experiment also showed that the LDH-Cl adsorption reaction rapidly at the adsorptive rate of 0.55 mg-P/g-LDH/min, implying that this adsorbent can be of use in the full-scale applications. The pH had a minimal effect on the LDH adsorption capacity in the range of 5 to 11, although the capacity dropped at the low pHs because of the change in LDH surface properties. Furthermore, other anions such as $Cl^-$ and $NO_3{^-}$ commonly found in the wastewater streams insignificantly affected the phosphate removal efficiencies, while $HCO_3{^-}$ ions had a negative effect on the LDH adsorption capacity due to its high selectivity. The phosphate removal experiment using the actual secondary effluent from a wastewater treatment plant showed the similar decrease in adsorption capacity, indicating that the bicarbonate ions in the wastewater were competing with phosphate for the adsorptive site in the surface of the LDH-Cl. Overall, the synthetic adsorbent material, LDH-Cl, can be a feasible alternative over other conventional chemical agents, since the LDH-Cl exhibits the high phosphate removal capacity with the low sensitivity to other environmental conditions.

• 대한방사성의약품학회지
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• 제8권2호
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• pp.119-128
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• 2022

2-Dimensional inorganic nanoparticles with high surface area and ion-exchangeable properties have been continuously growing based on nanotechnology in the field of nanomedicine. Among one of the 2-D nanoparticles, layered double hydroxide (LDH) has been intensively explored as drug delivery due to its low toxicity, enhanced cellular permeability, and high drug loading capacity. Moreover, controllable chemical composition makes possible varying isomorphic layered materials for therapy and imaging of diseases. In this review, specific structural characteristics of LDH were introduced, and its potential for application as a biocompatible therapeutic agent and diagnostic one was addressed in nuclear medicine, one of promising fields in nanomedicine.

• 한국결정성장학회지
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• 제8권1호
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• pp.36-41
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• 1998

유기화합물인 alkyl sulfonate를 층상이중수산화물에 삽입시킨 화합물을 합성하였다. X-선 회절 데이터와 alkyl sulfonate의 분자의 크기를 비교하여 층간 삽입된 alkyl sulfonate의 공간배열을 확입하였다. 층간 삽입된 alkyl sulfonate의 분자 사슬이 이중수산화물의 층에 수직되며 서로 반대 방향으로 배열되어 있음을 확인하였다.

• 한국결정성장학회지
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• 제33권2호
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• pp.78-82
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• 2023

The oxygen evolution reaction (OER) is the primary challenge in renewable energy storage technologies, specifically electrochemical water splitting for hydrogen generation. We report effects of Mo doping into Ni layered double hydroxide (Ni-LDH) microcrystal on electrocatalytic activities. In this study, Mo doped Ni-LDH were grown on three-dimensional porous nicekl foam (NF) by a facile solvothermal method. Homogeneous LDH structure on the NF was clearly observed. However, the surface microstructure of the nickel foam began to be irregular and collapsed when Mo precursor is doped. Electrocatalytic OER properties were analyzed by Linear sweep voltammetry (LSV) and Electrochemical impedance spectroscopy (EIS). The amount of Mo doping used in the electrocatalytic reaction was found to play a crucial role in improving catalytic activity. The optimum Mo amount introduced into the Ni LDH was discussed with respect to their OER performance.

• 한국재료학회지
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• 제33권10호
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• pp.377-384
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• 2023

Exploring earth-abundant, highly effective and stable electrocatalysts for electrochemical water splitting is urgent and essential to the development of hydrogen (H₂) energy technology. Iron-cobalt layered double hydroxide (FeCo-LDH) has been widely used as an electrocatalystfor OER due to its facile synthesis, tunable components, and low cost. However, LDH synthesized by the traditional hydrothermal method tends to easily agglomerate, resulting in an unstable structure that can change or dissolve in an alkaline solution. Therefore, studying the real active phase is highly significant in the design of electrochemical electrode materials. Here, metal-organic frameworks (MOFs) are used as template precursors to derive FeCo-LDH from different iron sources. Iron salts with different anions have a significant impact on the morphology and charge transfer properties of the resulting materials. FeCo-LDH synthesized from iron sulfate solution (FeCo-LDH-SO₄) exhibits a hybrid structure of nanosheets and nanowires, quite different from other electrocatalysts that were synthesized from iron chloride and iron nitrate solutions. The final FeCo-LDH-SO₄ had an overpotential of 247 mV with a low Tafel-slope of 60.6 mV dec^-1 at a current density of 10 mA cm^-2 and delivered a long-term stability of 40 h for the OER. This work provides an innovative and feasible strategy to construct efficient electrocatalysts.

• 멤브레인
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• 제20권4호
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• pp.290-296
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• 2010

Ethylene vinyl acetate (EVA-28)/Co-Al LDH 나노복합막은 유기화된 LDH를 사용하여 용액 삽입법으로 제조하였다. LDH의 유기화는 충간에 dodecyl sulfate (DS) anion을 삽입시켜서 제조하였다. 제조된 막의 특성을 알아보기 위하여 XRD, FT-IR, SEM을 측정하였다. EVA/LDH 나노복합막의 기체투과도는 압력 3, 4, 5 bar에서 LDH 함량 1, 3, 5 wt% 변화에 따라 조사하였다. $O_2$와 $CO_2$의 투과도는 1 wt% LDH에서 최소값을 가지며 LDH 함량이 증가하면서 입자의 응집현상으로 인하여 투과도는 증가하였다. $O_2$ 대한 $CO_2$의 선택도는 LDH 함량 1 wt%에서 최대값을 나타내고 그 이상에서는 감소경향을 나타내었다.

• 대한환경공학회지
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• 제33권6호
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• pp.426-431
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• 2011

본 연구의 목적은 마그네슘-철 층상이중수산화물(Mg-Fe LDH)을 이용하여 인공 지하수에서 바이러스를 제거하는 것이다. Mg-Fe LDH를 이용한 박테리오파지 T7의 제거를 관찰하기 위하여 다양한 실험조건에서 회분실험을 실시하였다. 실험 결과, Mg-Fe LDH에 의한 T7 제거는 빠른 반응으로써, 2~3시간 안에 평형에 도달하였다. Mg-Fe LDH의 T7 제거능은 $1.57{\times}10^8pfu/g$이었고, 제거율은 96%이었다. 또한, pH 6.2~9.1 범위에서 용액 pH가 T7 제거에 미치는 영향은 미미하였다. 음이온들($SO_4^{2-}$, $CO_3^{2-}$, $HPO_4^{2-}$)이 T7 제거에 미치는 영향은 중요하였는데, 이유는 이들 음이온들이 LDH상의 흡착지점에 T7과 경쟁하기 때문이다. 반면, 질산염($NO_3^-$)이 T7 제거에 미치는 영향은 미미하였다. 본 연구에 의하면, Mg-Fe LDH는 흡착제로써 수처리 과정에서 바이러스제거에 적용될 수 있을 것으로 판단된다.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.311-324
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• 2018

Herein,the Neodymium ion ($Nd^{3+}$) doped CoAl-LDH have been successfully prepared via co-precipitation method and was used as a precursor of Nd-doped CoAl-mixed metal oxides (MMO). The photocatalytic activity of doped LDH and MMO was investigated in the degradation of an azo dye, C.I. Acid Red 14, under visible light irradiation. DRS and PL analysis demonstrated decreasing in the band gap energy and recombination of photo-induced charge carriers of Nd-doped LDH and MMO compared with the pristine CoAL-LDH. Due to significant difference in photocatalytic performance. A power law empirical kinetic model was obtained for predicting the photocatalytic degradation efficiency.

• 멤브레인
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• 제23권2호
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• pp.151-158
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• 2013

EVA의 기체 분리 성질에 미치는 LDH의 영향을 알아보았다. Mg-Al LDH/EVA 나노복합막은 유기적으로 수정된 DS-LDH를 이용하여 용액 삽입법으로 제조되었다. DS-LDH는 LDH 층간에 DS 음이온을 삽입하여 제조하였다. 나노복합막의 구조는 XRD, FT-IR, SEM으로 알아보았다. DS-LDH가 EVA 내에 무질서하게 분산되었음을 XRD로부터 확인하였다. LDH가 3 wt% 첨가된 나노복합막에서 인장강도와 파단신율 모두 최댓값을 나타내었다. 열적 안정도 역시 EVA에 LDH가 첨가되면서 향상되었다. 1, 3, 5 wt%의 LDH를 함유한 LDH/EVA 나노복합막의 기체투과도는 $O_2$와 $CO_2$에 대하여 측정하였다. 3 wt% LDH를 함유한 경우 나노복합막의 $O_2$에 대한 투과도가 EVA막에서보다 53% 감소하였다. 하지만 $CO_2$ 투과도는 나노복합막의 기체 차단 특성에도 불구하고 LDH 내의 OH기와 $CO_2$ 간의 높은 친화력으로 인하여 기체투과도는 증가하였다.

• 한국세라믹학회지
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• 제35권5호
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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.