• 한국환경과학회지
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• 제8권3호
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• pp.399-409
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• 1999

The three domestic natural zeolites(Yong dong-ri (Y), Daesin-ri (D), Seogdong-ri (S)) harvested in Kyeongju-shi and Pohang-shi, Kyungsangbug-Do, were pretreatd with each of the NaOH, $Ca(OH)_2$ and NaOH following HCl solutions, and the removal performances of divalent haevy metals(Cu, Mn, Pb, and Sr) for natural and pretreated zeolites were investigated and compared in the single and mixed solutions. The natural zeolite-heavy metal system attained the final equilibrium plateau within 20 min, irrespective of initial heavy metal concentration. The heavy metal uptakes increased with increasing initial heavy metal concentration and pH. The heavy metal uptakes for natural zeolites decreased in the following sequences : D>Y>S among the natural zeolites; Pb>Cu>Sr>Mn among the heavy metals. The pretreated zeolites showed higher heavy metal removal performances than natural zeolites and decreased in the order of NaOH, NaOH following HCl, $Ca(OH)_2$ treatment among the pretreatment methods. The heavy metal ion exchange capacity by natural and pretreated zeolites was described either by Freundlich equation or Langmuir equation, but it followed the former better than the latter. The heavy metal uptakes for natural zeolites decreased in the mixed solution, in comparing with those in the single solution and especially, the manganese uptake decreased greatly in the mixed solution. The pretreated zeolites showed the improved removal performances of heavy metals in the mixed solution than in the single solution and the heavy metal uptakes by those in the mixed solution showed the same trends in the single solution among the chemical treatment methods and heavy metals.

• 한국환경과학회지
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• 제20권10호
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• pp.1337-1345
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• 2011

The removal performances of divalent heavy metal ions ($Pb^{2+}$, $Cu^{2+}$, $Cd^{2+}$, $Sr^{2+}$ and $Mn^{2+}$) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of $Pb^{2+}$ > $Cu2^{2+}$ > $Cd^{2+}$ > $Sr^{2+}$ > $Mn^{2+}$ based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for $Mn^{2+}$ decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90----- of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.

• 자원환경지질
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• 제28권3호
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• pp.231-241
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• 1995

It is well known that hydroxyapatite [$Ca_{10}(PO_4)_6(OH)_2$] have an exchangeability for various heavy metal ions in aqueous solution. To evalute the feasibility of employing the synthetic hydroxyapatites as an eliminatable exchanger for environmentally noxious caions in waste water, the adsorption properties, the removal capacities and the selectivity of the apatites for various cations were investigated in more detailed. The heavy metal cations have been exchanged in calcium part of hydroxyapatite. The order of the degree of amount exchanged of the investigated cations is $Pb^{2+}>Cd^{2+}>Zn^{2+}>Ba^{2+}$. The molar ratios between released $Cd^{2+}$ ions and remeved divalent metal cations in the reacted solution with hydroxyapatite are roughly close to an integer 1.0, suggesting that an ion-exchange reaction could have played a major role in the removal of heavy metals rather then an adsorption effect. The exchangeability of the hydroxyapatite powder of Ca/P molar ratio 1.67, which have specipic surface area of $104.5m^2g^{-1}$, appeared to be better then $237.6{\mu}g$ per g for $Pb^{2+}$ ions. The removal capacity of the heavy metal ions varies directly as particle size of hydroxyapatites. All evidences obtained indicate that the synthesized hydroxyapatite powders by precipitation reaction method can be employed as an effective cation exchanger for eliminating noxious ions in waste water even in some improvemental.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3681-3689
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• 2013

This study explored a direct SET-photochemical strategy to construct a new family of thioene conjugated-naphthalamide fluorophore based lariat-crown ethers which show strong binding properties towards heavy metal ions. Irradiations of designed nitrogen branched (trimethylsilyl)methylthio-terminated polyethylenoxy-tethered naphthalimides in acidic methanol solutions have led to highly efficient photocyclization reactions to generate naphthalamide based lariat type thiadiazacrown ethers directly in chemo- and regio-selective manners which undergo very facile secondary dehydration reactions during separation processes to produce their corresponding amidoenethio ether cyclic products tethered with electron donating diethyleneoxy- and diethyenethio-side arm chains. Fluorescence and metal cation binding properties of the lariat type enamidothio products were examined. The photocyclized amidoenethio products, thioene conjugated naphthalamide fluorophore containing lariat-thiadiazacrowns exhibited strong fluorescence emissions in region of 330-450 nm along with intramolecular exciplex emissions in region of 450-560 nm with their maxima at 508 nm. Divalent cation $Hg^{2+}$ and $Pb^{2+}$ showed strong binding to sulfur atom(s) in side arm chain and atoms in enethiadiazacrown ether rings which led to significant enhancement of fluorescence from its chromophore singlet excited state and concomitant quenching of exciplex emission. The dual fluorescence emission responses towards divalent cations might provide a new guide for design and development of fluorescence sensors for detecting those metals.

• Applied Biological Chemistry
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• 제41권8호
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• pp.587-594
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• 1998

The objective of this research was to characterize effects of Cu or Cd additions on chemistry of soil quality indices, such as pH, EC, cation distribution and buffering capacity. Metals were added at rates ranging from 0 to 400 mg $kg^{-1}$ of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable fractions. Adsorption of the added metals released cations into soil solution causing increases of ionic strength of soil solution. At metal additions of $200{\sim}400\;mg\;kg^{-1}$, EC of soil solution increased to as much as $2{\sim}4\;m^{-1}$; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations than monovalent cations were exchanged by Cu or Cd adsorption. The nutrient buffering capacity of soils was decreased due to the metal adsorption and release of cations. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu $kg^{-1}$ addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1997년도 총회 및 춘계 학술발표회 논문집
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• pp.8-11
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• 1997

Current methods of evaluating soil contamination by heavy metals rely on analyzing samples for total contents of metals or quantities recovered in various chemical extracting solutions. Results from these approaches provide only an index for evaluation because these methodologies yield values not directly related to bioavailability of soil-borne metals. In addition, even though concentrations of metals may be less than those required to cause toxic effects to biota, they may cause substantial effects on soil chemical parameters that determine soil quality and sustainable productivity. The objective of this research was to characterize effects of Cu or Cd additions on soil solution chemistry of soil quality indices, such as pH, EC, nutrient cation distribution and quantity/intensity relations (buffer capacity). Metals were added at rates ranging from 0 to 400 mg/kg of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable (strongly adsorbed) fractions. Adsorption of the added metals released cations into soil solution causing increases of soluble cation contents and thus ionic strength of soil solution. At metal additions of 200~400 mg/kg, EC of soil solution increased to as much as 2~4 dS/m; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations (Ca+Mg) than monovalent cations (K+Na) were exchanged by Cu or Cd adsorption. The loss of exchangeable nutrient cations decreased long-term nutrient supplying capacity or each soil. At 100 mg/kg or metal loading, the buffering capacity was decreased by 60%. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu/kg addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.

• 한국염색가공학회지
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• 제26권1호
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• pp.7-12
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• 2014

Nowdays, fluorescent rhodamine chemosensors have attracted a worldwide interest due to its ability to selectively detect heavy and transition metal cations. Due to the importance in environmental and biological toxic effects, the developments of fluorescent chemosensors have been received considerable attention in recent. Especially, a rhodamine-based chemosensor probes have been proved to be useful by exhibiting the efficient "off-on" fluorescence switching toward selected metal cations. This fluorophore can undergo the transformation from non-fluorescent and colorless spirolactam derivative to fluorescent ring-open form. In this study, a new fluorescent chemosensor was synthesized using rhodamine B through two-step procedures, and its selectivity and related optical property were characterized. Selectivity and sensitivity was found toward $Cu^{2+}$ guest molecules and then related optical properties of rhodamine B based fluorescent chemosensor compound were characterized using discussed. In addition, computational calculation was used to determine the HOMO/LUMO values.

• 대한화학회지
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• 제46권6호
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• pp.515-522
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• 2002

240$^{\circ}C$와 Ca/Si=2 몰 비율의 열수상태에서 합성된 고체 베타-디칼슘 실리케이트 하이드레이트($\beta-C_2$SH)는 Fe, Cu, Zn, Cd, 및 Pb와 같은 2가 금속 양이온에 대한 양이온 교환 성질을 보여준다. 그 고체에 희한 금속 양이온 흡인력은 $Fe^{2+}$〉$Cu^{2+}$〉$Zn^{2+}$〉$Cd^{2+}$ = $Pb^{2+}$의 순서로 됨이 밝혀졌다. 고체에 세슘 선택성은 $Li^+$, $Na^+$ 및 $K^+$와 같은 1가 양이온이나 $Ca^{++}$, $Mg^{++}$ 및 $Ba^{++}$와 같은 2가 양이온이 $Cs^+$보다 백배이상 진한 상태에서 나타내었다. $Cs^+$의 흡인력은 $Mg^{++}$의 존재하에서 최대치를 보여주었고, 반면에 $K^+$의 존재하에서 최소치를 보여주었다. 2가 금속이온에 대한 $\beta-C_2$SH의 다른 친화도는 이들 이온을 분리하는데 사용 할수 있다. 또한 $\beta-C_2$SH에 희한 금속 양이온 교환에 대한 반응경로 및 세슘 선택성이 연구되었다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.91-91
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• 2001

Nramp2, also known as DMT1 and DCT1, is a 12-transmembrane domain protein responsible for dietary iron uptake as well as metal ions such as lead, manganese, zinc, copper, nickel, cadmium, and cobalt. High expression of DMT1 increase lead uptake, and DMT1-dependent lead transport was H -dependent and inhibited by iron ions. The molecular mechanism of lead transport in CNS is as yet unknown. although interactions between iron and lead at the level of absorption have been known for some time. The process of lead uptake into astrocytes was not known yet. Nramp2 may mediate transport of heavy metal into astrocytes. We investigated whether Nramp2 mediate transport of lead into astrocytes. And we do whether Nramp2 was expressed highly by deprivation of iron in Astrocytes, and lead uptake into astrocytes was influenced by expression of Nramp2. Immortalized human fetal astrocyte(SV-FHA) cells were cultured in medium containing Dulbecco's modified Eagle's medium and treated with Deferoxamine. Northern blot analysis was done for determining mRNA level of DMT1 and lead uptake assay was done in incubation condition of pH 5.5 and 7.4.

• Toxicological Research
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• 제32권1호
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• pp.57-64
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• 2016

Recently several studies reported that the renal toxicity of lead (Pb) and cadmium (Cd) may exist in even a low level exposure. In terms of the deterioration of tubular function, it affects the loss of divalent metals and leads to other complications, so renal tubular effect of heavy metals should be well managed. Considering the exposure to heavy metals in reality, it is hard to find the case that human is exposed to only one heavy metal. We designed a cross-sectional study using Korean Research Project on the Integrated Exposure Assessment (KRIEFS) data to investigate the renal effects of multiple metal exposure in general population. We used blood Pb and urinary Cd as exposure measures, and urinary N-acetyl-${\beta}$-D-glucosaminidase (NAG) and ${\beta}_2$-microglobulin (${\beta}_2$-MG) as renal tubular impairment outcome. We conducted linear regression to identify the association between each heavy metal and urinary NAG and ${\beta}_2$-MG. And then, we conducted linear regression including the interaction term. Of 1953 adults in KRIEFS (2010~2011), the geometric mean of blood Pb and urinary Cd concentration was $2.21{\mu}g/dL$ (geometric $SD=1.49{\mu}g/dL$) and $1.08{\mu}g/g\;cr$ (geometric $SD=1.98{\mu}g/g\;cr$), respectively. In urinary Cd, the strength of the association was also high after adjusting (urinary NAG: ${\beta}=0.44$, p < 0.001; urinary ${\beta}_2$-MG: ${\beta}=0.13$, p = 0.002). Finally, we identified the positive interactions for the two renal biomarkers. The interaction effect of the two heavy metals of ${\beta}_2$-MG was greater than that of NAG. It is very important in public health perspective if the low level exposure to multiple heavy metals has an interaction effect on kidney. More epidemiological studies for the interaction and toxicological studies on the mechanism are needed.