• The Korean Journal of Malacology
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• v.29 no.4
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• pp.377-380
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• 2013

This study investigated concentration of metal ions in sediment and intersexuality in Polymesoda erosa and Lutraria lutraria. Samples were collected from five areas of Ha Long Bay in October, 2012. The concentration of metal ions showed that Al ($37390.0{\pm}11816.5mg/kg$) was highest and Mn ($360.4{\pm}101.4mg/kg$) was second high concentration. Cd ($0.04{\pm}0.05mg/kg$) was lowest. The intersexuality was 14.3% in P. erosa and 9.1% in L. lutraria that observed only in female.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.218-222
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• 1998

Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.497-502
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• 1999

Removal of Pb(Ⅱ), Cu(Ⅱ), Cr(Ⅲ), and Zn(Ⅱ) ions from aqueous solutions using the adsorption process on domestic loess minerals has been investigated. Variations of contact time, pH, adsorption isotherms and selectivity of coexisting ions and leachate were experimental parameters. YDI, YPT and KRT samples diluted in 1% aquous solution which was adjusted pH 10.8, 8.0 and 6.50, respectively. The result of XRD measurement, Quartz was mainly observed in all samples. In the case of KRT sample, Kaolinite, Feldspar, Chlorite consisting of clay minerals shows almost same pattern with YPT samples. Different properties showed from the YDI sample containing Iillite, remarkably. For all the metals, maximum adsorption was observed at 30min∼60min. Adsorption of metal ions on loess minerals were reached an equilibrium by shaking the solution for about 30min. Removal efficiency of Pb(Ⅱ) ion for KRT, YPT and YDI were 84.7%, 92% and 100%, respectively. The Cu(Ⅱ) and Zn(Ⅱ) adsorptivity on KRT showed the low in various pH solution However, those on YPT and YDI were high than 90% except for the pH 2 solution. The orders of adsorptivities for domestic loess minerals showed as following : YPT>KRT>YDI. The adsorption isotherms of Cu(Ⅱ) and Zn(Ⅱ) ions on clay minerals were fitted to a Freundlich's. Freundlich constants(1/n) of KRT and YPT domestic loess minerals were 0.63, 0.97 and 0.36, 0.25, respectively.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.190-195
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• 2015

Here, we demonstrated a $Pb^{2+}$ detecting aptasensor using $Pb^{2+}$-sensitive DNAzyme-conjugated gold nanorods (GNRs). Fluorescent DNA substrates that were initially quenched by GNRs, are released in response to $Pb^{2+}$ ions to give a substantial fluorescence signal. The GNR-tethered DNAzyme is reusable at least three times with a LOD of 50 nM.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.691-697
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• 2005

Waste sludge may be used to recovery wastewater contaminated with heavy metals. The waste sludge is an inexpensive readily available source of biomass for biosorption with metal-bearing wastewater. The biosorption of heavy metals such as Pb(II), Cu(II), Cr(II), and Cd(II) onto waste sludge was investigated in batch ex­periments and waste sludge loaded heavy metals was separated by dissolved air flotation. The biosorption equi­bria of heavy metals could be described by Langmuir and Freundich isotherms. The adsorption capacity for waste sludge was in the sequence of Pb(II)>Cr(II)>Cu(II)>Cd(II). The system attained equilibrium about 20 min. The Langmuir and Freundlich adsorption model effectively described the biosorption equilibrium of Cu(II) and Cr(II) ions on waste sludge. Maximum adsorption capacity of Cu(II) and Cr(II) were 196.08 and 158.73 mg/g, respectively. Solid-liquid separation efficiencies were kept above $95\%$ on waste sludge loaded heavy metals, and were decreased with pH increasing.

• Journal of Soil and Groundwater Environment
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• v.20 no.1
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• pp.56-64
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• 2015

Acid mine drainage occurrence is a serious environmental problem by mining industry, it usually contains high levels of metal ions, such as iron, copper, zinc, aluminum, and manganese, as well as metalloids of which arsenic is generally of the greatest concern. An indigenous plant extract was used to produce calcium carbonate from Canavalia ensiformis as effective biomaterial, and its ability to form the calcium carbonate under stable conditions was compared to that of purified urease. X-ray diffraction and scanning electron microscopy were employed to elucidate the mechanism of calcium carbonate formation from the crude plant extracts. The results revealed that urease in the plant extracts catalyzed the hydrolysis of urea in liquid state cultures and decreased heavy metal amounts in the contaminated soil. The heavy metal amounts were decreased in the leachate from the treated mine soil; 31.7% of As, 65.8% of Mn, 50.6% of Zn, 51.6% of Pb, 45.1% of Cr, and 49.7% of Cu, respectively. The procedure described herein is a simple and beneficial method of calcium carbonate biomineralization without cultivation of microorganisms or further purification of crude extracts. This study suggests that crude plant extracts of Canavalia ensiformis have the potential to be used in place of purified forms of the enzyme during remediation of heavy metal contaminated soil.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.704-712
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• 2006

This research was designed to investigate the removal of heavy metals, such as $Al^{3+}$, $Cu^{2+}$, $Mn^{2+}$, $Pb^{2+}$ and $Zn^{2+}$, by adsorption on clay minerals. Bentonite(Raw-Bentonite), $Ca^{2+}$ and $Na^+$ ion exchanged bentonite(Ca- and Na-Bentonite) and montmorillonite, such as KSF and K10 from Sigma Aldrich, were used as adsorbents. The component of five inorganic adsorbents was analyzed by XRF, and the concentration of metal ions was measured by ICP. The cation exchange capacity(CEC) and the particle charge of adsorbents were measured. The initial concentration range of metal ions was $10{\sim}100$ mg/L. From the experimental results, it was shown that the adsorption equilibrium was attained after $1{\sim}2$ hours. The maximum percentage removal of $Al^{3+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ on Na-Bentonite were more than 98% and that of $Mn^{2+}$ was 66%. $Al^{3+}$ was leached out from KSF with the higher concentration of hydrogen ion. Percentage removals of $Pb^{2+}$ and $Zn^{2+}$ on KSF were 88% and 59%, respectively. In general, the percentage removal of metal ions was decreased with the higher initial concentration of metal ions. The adsorption capacity of metal ions on Na-Bentonite was $1.3{\sim}19$ mg/g. Freundlich equation was used to fit the acquired experimental data. As the results, the adsorption capacity of metal ions was in the order of Na-Bentonite$\gg$Raw-Bentonite$\cong$K10>Ca-Bentonite>KSF. Freundlich constant, K of Na-Bentonite was the largest for metal ions. The order K of Na-Bentonite was Al>Cu>Pb>Zn>Mn, and the adsorption intensity(1/n) was determined to be $0.2{\sim}0.39$.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.87-91
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• 2021

Various Cu ions are discharged into water from various industries, which results in a severe trouble for groundwater, soil, air, and eventually animals and humans. In this work, graphene oxide (GO) is introduced as a Cu removal absorber and the real-time monitoring method is demonstrated. The results show that GO is a very effective material to absorb Cu ions in the solution. In addition, the residual Cu ions in the solution is monitored via optical transmittance method, which well match with Inductively Coupled Plasma Mass Spectrometer (ICP-MS) analysis.

• Journal of Korean Society on Water Environment
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• v.33 no.5
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• pp.556-562
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• 2017

Heavy metals in water systems are being managed on the concentration-based guidelines in Korea. However, various chemicals present in water can interact with heavy metals affecting their toxicity. Such interactions are not considered in the concentration-based guidelines. This study investigated the effect of hardness and coexisting heavy metals on heavy metal toxicity to emphasize the importance of having the effect-based guidelines together with the concentration-based guidelines in water management. The toxic effects of Cd, Zn, or mixtures of Cd and Zn were studied with Daphnia magna as a test species following the standard test method at different hardness conditions (100, 200, and $300mg\;L^{-1}$ as $CaCO_3$). The toxicities of single metal solutions and mixtures showed a decreasing trend with increasing hardness, and this can be attributed to the competition between heavy metals and cations such as calcium ions ($Ca^{2+}$) that cause hardness. The predicted toxicities of the heavy metal mixtures from the single metal toxicity deviated from the measured toxicities, and the predicted toxic effects tend to be greater than the measured toxic effects suggesting that Cd and Zn are in competition. This shows the limitations of using predicted toxic effects and the needs for further studies on mixture toxicities. Overall, this study shows that the management of heavy metals in waters needs to employ the effect-based guidelines together with the concentration-based guidelines.

• Archives of Pharmacal Research
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• v.16 no.1
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• pp.78-81
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• 1993

Solution equilibria of the thmary systems $UO_2(II)$, La(III), Ce(III)-N-(2-acetamido)-iminodiacetic acid and dicarboxylic amino acids are studied potentiometrically. The formation of 1:1:1 mixed ligand complexes are inferred from the potentiometric titration curves. The formation constants of the different binary and thmary complexes in such system are evaluated at t=$24\pm{0.1}^\circ{C}\;and\;\mu=0.1\;mol\;dm^{-3}(kNO_3)$. It is deduced that the temary complex is more stable than the corresponding binary amino acid anion complex. Moreover, the order og stability of the binary or temary complexes in terms of nature of amino acid and metal ion is investigated and discussed.