• Bulletin of the Korean Chemical Society
• /
• 제34권8호
• /
• pp.2367-2374
• /
• 2013

Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis. The obtained organic-inorganic composite was effectively employed as a heterogeneous basic catalyst for synthesis of ${\alpha},{\beta}$-unsaturated carbonyl compounds. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present catalyst.

• Journal of the Korean Wood Science and Technology
• /
• 제48권6호
• /
• pp.896-906
• /
• 2020

Wood deterioration experiments were carried out for 6 months in an intertidal zone of South Korea to monitor the changes in the chemical properties of two types of species, Korean red pine and sawtooth oak. The results of FT-IR spectra and XRD patterns have shown that the chemical properties of the wood did not change significantly during the 6-month burial period. However, the brightness of the surface decreased after burial; the value of the sawtooth oak sample was lower than that of the Korean red pine sample owing to an accumulation of inorganic compounds in cell lumen as observed by ICP analysis. Among the inorganic compounds, sodium and sulfur concentrations increased significantly over the burial period compared with the control. Further, the maximum moisture content decreased from 199% to 136% in the Korean red pine and 62% to 60% for the sawtooth oak. Nevertheless, the major chemical composition of both the wood species did not change significantly during the 6-month burial period, whereas, the crystallinity decreased with an increasing burial period owing to an accumulation of inorganic compounds in the lumen.

• 전기화학회지
• /
• 제12권2호
• /
• pp.131-141
• /
• 2009

이산화탄소의 유용한 화합물로의 전환은 온실가스 증가로 인한 기후변화에 따른 환경문제의 해결 뿐 아니라 탄소원의 재활용이란 관점에서 무척 중요하다. 그러나 탄소화합물 중 가장 안정된 이산화탄소를 다른 유용한 화합물로 변환시키기 위해서는 에너지가 투입되어야 하고 효과적인 전환을 위하여 촉매의 개발 및 관련된 반응 조건의 확립이 필요하다. 본 총설에서는 그 동안 전기화학적으로 이산화탄소를 변환시킨 연구 내용들을 전극재료, 무기화합물, 효소를 이산화탄소의 환원 촉매로서 이용한 경우로 나누어 전체적으로 살펴보았다. 선택성이 좋고 효율적이며 안정성을 가진 촉매는 아직 개발되지 않은 상황이므로 앞으로 많은 연구가 진행되어야 할 분야이다.

• Ocean Science Journal
• /
• 제40권2호
• /
• pp.61-66
• /
• 2005

Benthic amphipod, Grandidierella japonica widely inhabits the Korean coastal waters and is developed as a standard test species for sediment toxicity tests. We exposed G. japonica to various pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), tributyltin [TBT], ammonia and 7 polycyclic aromatic hydrocarbon (PAH) compounds (acenaphthene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene) to estimate the no observed effect concentration (NOEC) and the median lethal concentration (LC50) of each pollutant during the 96-hour acute exposure. Among all tested pollutants, TBT was most toxic to G. japonica, and Rg was most toxic among inorganic metals. The toxicity of pyrene to G. japonica was greatest among PAH compounds, followed by fluoranthene, phenanathrene, acenaphthene, fluorene and naphthalene. The toxicity of PAH compounds was closely related to their physico-chemical characteristics such as $K_ow$ and water solubility. G. japonica responded adequately to pollutant concentrations and exposure durations, and the sensitivity of G. japonica to various inorganic and organic pollutants was generally comparable to other amphipods used as standard test species in ecotoxicological studies, indicating this species can be applied in the assessment of environments polluted by various harmful substances.

• Journal of Plant Biology
• /
• 제14권2호
• /
• pp.1-6
• /
• 1971

When germination beds of carrot seeds were treated with either 0.01M or 0.05M concentrations of Ca(NO3)2, CaSO4, MgSO4, K2SO4 and KH2PO4, an acceleration in the germination rate was observed in the groups treated with 0.01M KH2PO4 and 0.05M MgSO4 and 0.05M Ca(NO2)3. In earlier work by the author with acetone a similar result was observed and reported. The pH range in these experiments was maintained between 5.0 and 6.0. It was found that the groups treated with 0.05M K2SO4, 0.05M Ca(NO3)2, 0.05M Ca(NO3)2, 0.05M MgSO4, 0.01M KH2PO4, 0.01M Ca(NO3)2 germinated earlier than the control group. The acceleration of the germintion rate varied with the inorganic compounds used in the following descending order; 0.01M KH2PO4, 0.05M Ca(NO3)2, 0.05M K2SO4, 0.05M CaSO4 and 0.05M KH2PO4. As a result of these expriments, it occurs to the author that in the germination of carrot seeds some inorganic compounds appear to activate the osmotic function of carrot seeds causing acceleration in the germination rate.

• Membrane and Water Treatment
• /
• 제1권1호
• /
• pp.1-12
• /
• 2010

Membrane distillation process was used for purification of pre-treated natural water (tap water). The rejection of inorganic and organic compounds in this process was investigated. The obtained rejection of inorganic solutes was closed to 100%, but the volatile organic compounds (VOCs) diffused through the membrane together with water vapour. The content of trihalomethanes (THMs) in the obtained distillate was two-three fold higher than that in the feed, therefore, the rejection of the total organic compounds present in the tap water was reduced to a level of 98%. The intensive membranes scaling was observed during the water separation. The morphology and composition of the fouling layer was studied using scanning electron microscopy coupled with energy dispersion spectrometry. The influence of thermal water pre-treatment performed in a heat exchanger followed by filtration on the MD process effectiveness was evaluated. This procedure caused that significantly smaller amounts of $CaCO_3$ crystallites were deposited on the membrane surface, and a high permeate flux was maintained over a period of 160 h.

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 1986년도 추계학술대회
• /
• pp.506-508
• /
• 1986

Metabolic activity of inorganic nitrogenous compounds affects not only microbial growth but also metabolite production in fermentation technology. We have worked on the enzymes participating in ammonia assimulation of some fermentation bacteria. This paper summarizes the results on glutamine synthetase and its application in practical field. Glutamine synthetase (L-glutamate:ammonia ligase, EC. 6.3.1.2) catalyzes the formation of glutamine from glutamate and ammonia at the expense of cleavage of ATP and inorganic phosphate. The enzyme plays a dual role in nitrogen metabolism in bacteria; it is a key enzyme not only in the biosynthesis of various compounds through glutamine but also in the regulation of synthesis of some enzymes involved in the metabolism of nitrogenous compounds. The detailed works with the Eschericia coli and other enterobacterial enzymes revealed that glutamine synthetase is controlled by the following complex of mechanisms: (a) feedback inhibition by end products, (b) repression and derepression of enzyme synthesis, (c) modulation of enzyme activity in response to divalent cation and (d) covalent modification of enzyme protein by adenylylation and its cascade control. Comparative studies have also been made on the enzymes from other organisms.

• Environmental Analysis Health and Toxicology
• /
• 제19권2호
• /
• pp.141-151
• /
• 2004

We exposed juvenile puffer fish, Takifugu obscurus(30 days after hatching) to various aqueous pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), 2 organotin compound.; (tributyltin ［TBT］ and triphenyltin［TPhT］) and 5 polycyclic aromatic hydrocarbon (PAH) compounds (chrysene, fluoranthene, naphthalene, phenanthrene and pyrene) to estimate median lethal concentrations (LC50s) of each pollutant after the 96-hour acute exposure. Among the inorganic metals, Hg (52 $\mu\textrm{g}$/L; 96-h LC50) was most toxic to test animals and followed by Ag (164 $\mu\textrm{g}$/L), Cu (440 $\mu\textrm{g}$/L) and Cd (1180 $\mu\textrm{g}$/L). Aqueous TBT was more toxic between the two organotins; the 96-h LC50 for TBT (5.1 $\mu\textrm{g}$/L) was 3 times lower than that of TPhT (17.3 $\mu\textrm{g}$/L). The acute toxicity of PAH compounds was highest for chrysene (1.5 $\mu\textrm{g}$/L; 96-h LC50) and decreased in the order of pyrene (65 $\mu\textrm{g}$/L) > fluoranthene (158 $\mu\textrm{g}$/L) > phenanthrene (432 $\mu\textrm{g}$/L) > naphthalene (8690 $\mu\textrm{g}$/L). The toxicity of PAH compounds wat closely related to their physico-chemical characteristics such as $K_{ow}$ and water solubility, and well explained by simple QSAR relationship. The sensitivity of puffer fish to various inorganic and organic pollutants was generally comparable to various fish species widely used as standard test species in previous studies and further evaluation should be conducted to develop adequate testing procedure for T. obscurus when used in various toxicity tests.

• 폴리머
• /
• 제36권5호
• /
• pp.622-627
• /
• 2012

친환경 수성 코팅제의 물성 강화 및 VOCs의 저감 특성을 연구하기 위해서 poly(tetramethylene glycol) 2000, polycarbonate diol 2000, isophorone diisocyanate, dimethylolpropionic acid, 그리고 titanium dioxide를 사용하여 유/무기 하이브리드 수분산 폴리우레탄 코팅제를 제조하였다. R ratio([NCO]/[OH])에 따른 코팅제의 필름 물성 및 무기물의 적용으로 인한 VOCs의 저감 특성에 대해서 연구한 결과 R ratio가 1.5 이상인 경우에서 코팅제로 적합함을 확인하였으며 이는 하드 세그먼트의 영향으로 여겨지며 $TiO_2$의 적용으로 코팅 후 VOCs의 저감 특성을 확인하였다.

• 공업화학
• /
• 제16권5호
• /
• pp.719-723
• /
• 2005

Tetraethyl orthosilicate (TEOS) 혹은 1,2-bis(triethyoxysilyl)ethane (BTSE)과 여러 종류의 organosilane들을 공중합하여 유 무기 혼성 메조포러스 물질들을 제조하고, 이들이 공기 중의 휘발성 유기화합물(VOC)들을 흡착 제거하는 능력을, TEOS 만을 사용하여 제조한 친수성 무기 메조포러스물질인 SBA-15와 비교 평가하였다. 유기 구조의 도입에 의한 소수성의 증대는 메조포러스 물질이 VOC를 흡착 제거하는데 긍정적 효과를 줌을 관찰하였다. 특히 BTSE와 phenyl triethoxysilane을 중량비 90:10으로 공중합한 유 무기 혼성 메조포러스 물질의 VOC 제거 능력은 우수하였다. 또, 물속에 분산된 기름 성분을 흡착 제거하는데 유 무기 혼성 메조포러스 물질들을 유용하게 응용할 수 있음도 정성적으로 관찰하였다.