• Membrane and Water Treatment
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• v.10 no.3
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• pp.239-244
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• 2019

Plating wastewater containing various heavy metals can be produced by several industries. Specifically, we focused on the removal of copper (Cu2+) and nickel (Ni+) ions from the plating wastewater because all these ions are strictly regulated when discharged into watershed in Korea. The application of both nanofiltration (NF) and reverse osmosis (RO) technologies for the treatment of wastewater containing copper and nickel ions to reduce fresh water consumption and environmental degradation was investigated. In this work, the removal of copper (Cu2+) and nickel (Ni+) ions from synthetic water was studied on pilot scale remove by before using two commercial nanofiltration (NF) and reverse osmosis(RO) spiral-wound membrane modules (NE2521-90 and RE2521-FEN by Toray Chemical). The influence of main operating parameters such as feed concentration on the heavy metals rejection and permeate flux of both membranes, was investigated. Synthetic plating wastewater samples containing copper ($Cu^{2+}$) and nickel ($Ni^{2+}$) ions at various concentrations(1, 20, 100, 400 mg/L) were prepared and subjected to treatment by NF and RO in the pilot plant. The results showed that NF, RO process, with 98% and 99% removal for copper and nickel, respectively, could achieve high removal efficiency of the heavy metals.

• Textile Coloration and Finishing
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• v.24 no.3
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• pp.158-164
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• 2012

Rhodamine dyes belong to xanthene family has excellent photostability and photophysical properties. In rhodamine dyes, Rhodamine 6G and its precursors also have xanthene chromophore and it shows high fluorescent quantum yield. Rhodamine 6G derivates are simple to synthesis and its high sensitivity and water solubility are suitable as good chemosensor. In this regard, Rhodamine 6G derivates which have selectivity to specific metal cation can used to detect various heavy metal ions. In this study, rhodamine 6G derivatives were synthesized by reaction of rhodamine 6G hydrazide and glyoxal and 4-phenyl thiosemicarbazide and it showed colorimetric and fluorescence sensing toward $Hg^{2+}$ ion. This novel chemosensor was analyzed and measured on UV-Vis and fluorescence spectrophotometer. HOMO/LUMO values were also calculated by computational calculation.

• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.967-973
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• 1993

The effect on the hydration of cement was that Cu and Pb reacted with alkali to form soluble hydrates at theinitial stage and then there followed a slow reaction forming insoluble metal hydroxides. These hydroxides were deposited on the surface of cement particles providing a barrier against further hydration. But as a slow reaction continued, the insoluble layers were eventually destroyed and the hydration reaction resumed. Thereafter, another retardation occured by restricting the polymerization of silicates, shown by FT-IR spectroscopy analysis. In the case of Cr, as its reaction with cement caused H2O, the coordinator of Cr complex, to replace or polymerize with OH-, the formation of Cr complex promoted the leakage of OH- and increased the heat of dissolution. So the total heat evolution during hydration was larger than that in the case of Pb or Cu. The retarding effect of heavy metal ions was in the order Pb>Cu>Cr.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.231-235
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• 2020

Industrialization and modern developments have led to an influx of toxic heavy metals into the aquatic environment, and the accumulation of heavy metals has serious adverse effects on humans. Among the various heavy metal treatment methods, adsorption is very useful and frequently used. Plastic materials, such as polypropylene and polyethylene, have been widely used as filter media due to their mechanical and chemical stability. However, the surface of plastic material is inert and therefore the adsorption capability of heavy metals is very limited. In this study, granular media and fiber media composed of polypropylene and polyethylene are used, and the surface modification was conducted in order to increase adsorption capability toward heavy metals. Oxygen plasma generated hydroxyl groups on the surface of the media to activate the surface, and then acrylic acid was synthesized on the surface. The grafted carboxyl group was confirmed by FT-IR and SEM. Heavy metal adsorption capability of pristine and surface modified adsorbents was also evaluated. Overall, heavy metal adsorption capability was increased by surface modification due to electrostatic interaction between the carboxyl groups and heavy metal ions. Fibrous PP/PE showed lower improvement compared to granular PP media because pore blockage occurred by the surface modification step, thereby inhibiting mass transfer.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.28-32
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• 2016

There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

• Economic and Environmental Geology
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• v.29 no.6
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• pp.733-738
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• 1996

Heavy metal equilibria in the Dongnam stream which receives the wastewater from mining activities are investigated to provide some basic data for the management of small stream with acid mine drainage. Saturation, undersaturation, and supersaturation of some heavy metal ions with respect to some mineral phases are evaluated by saturation index (logIAP/Ksp). The $Al^{3+}$ activities showed equilibrium with $AIOHSO_4$ solid phase below a pH of 6.0. The $Fe^{3+}$ activities appeared to be controlled by Fe $(OH)_{3(amorphous)}$ solid phase below a pH of 4.0. $Zn^{2+}$ activities appeared to be regulated by $ZnCO_3$ solid phase above a pH of 6.8. Some heavy metal activities appeared to be depended upon the pH.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1998.10a
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• pp.276-279
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• 1998

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.89-93
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• 2003

• Food Industry And Nutrition
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• v.5 no.2
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• pp.65-69
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• 2000

• Journal of environmental and Sanitary engineering
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• v.14 no.2
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• pp.46-55
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• 1999

This study compared the adsorption characteristics of heavy metal ions by crab shell, treated crab shell with 2N-HCl, treated crab shell with 4%-NaOH, chitin and chitosan.Using crushed crab shell, the heavy metal ions removal rates of $Cd^{2+}$ and $Zn^{2+}$ were about 70-80% in 45minutes, but the removal rates of $Cu^{2+}$, $Cr^{6+}$ and $Pb^{2+}$ was less than 10%, 10% and 30%, respectively. For the by-products crab shell by 2N-HCl treatment, it was shown that the removal rates of $Cu^{2+}$ and $Pb^{2+}$ were about 70-80% in 45minutes reaction. But, some problems were observed, that the contained protein in crab shell was changed into gel in the mixing solution after a few hours. For the by-products of crab shell by 4%-NaOH treatment, the removal rates of Pb and Zn were about 90% in 45 minutes, and those of capacity of chitin and chitosan powder was better than those of the other by-products. The more adding to the adsorbent dosages increased the removal rates, and the adsorption reaction was rapidly occurred in a few minute. Using 1.0 wt% chitin powder, the heavy metal removal rates were ordered $Cu^{2+}$(94%) > $Zn^{2+}$(89%) > $Cd^{2+}$(88%) > $Pb^{2+}$(77%) > $Cr^{6+}$(58%) in 45 minutes. Using 1.0 wt% chitosan powder, the heavy metal removal rates were ordered $Cu^{2+}$(99%) > $Pb^{2+}$(96%) > $Cd^{2+}$(79%) > $Zn^{2+}$(71%) > $Cr${6+}$(46%) in 45minutes. The degree of degree of deacetylation by prepared chitosan was 91%.The Freundlich adsorption isotherm of $Cu^{2+}$, $Cd^{2+}$ and $Zn^{2+}$, when it was applied to 1.0 wt% chitosan powder in minutes, can be acceptable very strictly. The equation constant (1/n) for $Cu^{2+}$, $Cd^{2+}$ and $Zn^{2+}$ were 0.54 0.41 and 0.23 respectively.