• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.626-631
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• 2006

The adsorption features of copper ion have been investigated by taking the barley residue which occurring from the beer production process as an adsorbent. Under the experimental conditions, adsorption equilibrium of copper ion was attained within 30 minutes after the adsorption started and the adsorption reaction was observed to be first order. As the temperature increased, the adsorbed amount of copper ion at equilibrium was also increased, which indicated that the adsorption reaction was endothermic. Based on the experimental results which obtained by varying the temperatures, several thermodynamic parameters for copper adsorption reaction were estimated. Regarding the electrokinetic behavior of barley residue, its electrokinetic potential was observed to be positive below pH 5 and turned into negative above this pH. In the pH range from 1.5 to 4, copper adsorption was found to be increased, which was well explained by the electrokinetic behavior of barley residue in the pH range. When nitrilotriacetic acid, which is a complexing agent, was coexisted with copper ion, equilibrium adsorption of copper ion was decreased and this was presumed to be due to the formation of metal complex. In addition, the adsorbed amount of copper ion was examined to be increased when $KNO_3$ was coexisted, however, it approached a saturated value above a certain concentration of $KNO_3$.

• Resources Recycling
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• v.30 no.6
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• pp.36-42
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• 2021

Spent lithium-ion batteries are treated by reduction-smelting at high temperatures to recover valuable metals. Solvent extraction and precipitation of the HCl leaching solution of reduction-smelted metallic alloys resulted in a filtrate containing Ni(II) and a small amount of Si(IV). Adsorption and precipitation experiments were conducted to recover pure Ni(II) compounds from the filtrate. Si(IV) was selectively loaded onto polyacrylamide, but this method did not efficiently filter the solution due to an increase in viscosity. The addition of Na₂CO₃ as a precipitant to the filtrate led to the simultaneous precipitation of Ni(II) and Si(IV). However, it was possible to recover nickel oxalate with a purity higher than 99.99% by selectively precipitating Ni(II) with the addition of Na₂C₂O₄ as a precipitant.

• Membrane Journal
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• v.24 no.6
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• pp.472-483
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• 2014

This study is preparation of microporous membranes by using macrocyclic metal ion complexes and extended cage complexes. It is a more favorable way to existing methods because polymer and metal ion-ligand complex system provides a fine control over the phase transition behavior. Chemical functionalization of the polar surface can be obtained. Metal-templated condensation of cyclohexanedione dioxime, hydroxyphenylboronic acid in the presence of metal salts proceeds cleanly in methanol to furnish the metal clathrochelate complexes. Organic/inorganic hybrid membranes were prepared with polyethersulfone (PES), polyvinylpyrrolidone (PVP), ethyleneglycol butyl ether (BE), metal clathrochelate s and DMF by using nonsolvent induced phase inversion method. The structure of membranes was characterized with scanning electron microscopy (SEM) and microflow permporometer. The addition of Fe(II) clathrochelate complex with p-hydroxyphenyl group leads to changes of membrane morphology such as narrow mean pore size distribution, increase of surface pore density and decrease of the largest pore size.

• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.157-164
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• 1977

In the present study, the proxidant effect of ferrous and cupric chlorides which added to soybean oil and its fried noodle in the same concentration of the city water and the physically refined underground water were determined. As the inhibitor of metal proxidation, BHA and citric acid which are used widely in oil industry as antioxidants were compared. In both cases of soybean oil and its fried noodle, the addition of cupric chloride and ferrous chloride showed prominent proxidant effect. Especially, cupric chloride marked more proxidant effect than ferrous chloride by 3 to 6 times with the elapse of time. In the inhibition activity of metal proxidation, citric acid was more effective than BHA. The 1ppm of Cu +0.01% of citric acid treated soybean oil showed less proxidant effect than the control at the later stage. The inhibition activity of citric acid on $Fe^{++}$ in soybean oil was more effective than $Cu^{++}$ in soybean oil.

• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1147-1161
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• 1995

When ceramic membrance was made from metal salt solution in place of metal akoxide solution, crack free and good adhesion to supporter was optimized for sol stability and good adhesion force. A starting sol was prepared from aluminum oxychloride aqueous solutjion in order to inhibit the grain growthof Al2O3 during heat treatment. The crack free dip coating can't be achieved in 1mol/ι zirconium oxychloride solution because of the high viscosity which interferes with the hydration copolymerization between Al3+ ion and Zr4+ ion. Thus Al2O3-ZrO2 sol stability and viscosity for dip coating was effective when 0.01 mol/ι zirconium oxychloride was added. The minimizing of crack and achieving better adhesion to the supporter wa obtained by microwave drying, surfactant addition and ultrasonic dip coating in wet atmosphere. The result seems to minimize the capillary force and improve the adhesive ability to supporter during the process. Where the average pore size of Al2O3-ZrO2 ultrafilter ceramic membrane measured 17 Å by the BET method and observed γ-Al2O3 phase with tetragonal zirconia after firing at 700℃.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.25-31
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• 2016

In this research, to analyze the concentration of heavy metal ions in water, we tried to find the measuring time at which the faradaic electric currents flowing by the pure oxidation-reduction reaction from the pushing up mercury electrode of the stripping scan square wave voltammetry(SV+SWV) methods system becomes larger than the capacitance electric current. In order to do this, a method for analyzing signals using FPGA has been designed and we conducted 120 experiments using it. As a result, when the frequency of the square wave is 40Hz, The valid potential-current signal was measured from 96.6667% to 96.7155% of the end of the pulse of the forward and reverse, and the optimal signal was measured at 96.6667%. In addition, the experiment was carried out 40 times by changing the pulse height of the square wave from 10Mv to 40Mv. As a result, at a size smaller than 40Mv, there is little change in the magnitude of the potential-current, and an invalid signal was generated when it is out of this size.

• Nutrition Research and Practice
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• v.1 no.1
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• pp.29-35
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• 2007

Trace mineral studies involving metal ion chelators have been conducted in investigating the response of gene and protein expressions of certain cell lines but a few had really focused on how these metal ion chelators could affect the availability of important trace minerals such as Zn, Mn, Fe and Cu. The aim of the present study was to investigate the availability of Zn for the treatment of MC3T3-E1 osteoblast-like cells and the availability of some trace minerals in the cell culture media components after using chelexing resin in the FBS and the addition of N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN, membrane-permeable chelator) and diethylenetriaminepentaacetic acid (DTPA, membrane-impermeable chelator) in the treatment medium. Components for the preparation of cell culture medium and Zn-treated medium have been tested for Zn, Mn, Fe and Cu contents by atomic absorption spectrophotometer or inductively coupled plasma spectrophotometer. Also, the expression of bone-related genes (ALP, Runx2, PTH-R, ProCOL I, OPN and OC) was measured on the cellular Zn depletion such as chelexing or TPEN treatment. Results have shown that using the chelexing resin in FBS would significantly decrease the available Zn (p<0.05) $(39.4{\pm}1.5{\mu}M\;vs\;0.61{\pm}10.15{\mu}M)$ and Mn (p<0.05) $(0.74{\pm}0.01{\mu}M\;vs\;0.12{\pm}0.04{\mu}M)$. However, levels of Fe and Cu in FBS were not changed by chelexing FBS. The use of TPEN and DTPA as Zn-chelators did not show significant difference on the final concentration of Zn in the treatment medium (0, 3, 6, 9, $12{\mu}M$) except for in the addition of higher $15{\mu}M\;ZnCl_2$ which showed a significant increase of Zn level in DTPA-chelated treatment medium. Results have shown that both chelators gave the same pattern for the expression of the five bone-related genes between Zn and Zn+, and TPEN-treated experiments, compared to chelex-treated experiment, showed lower bone-related gene expression, which may imply that TPEN would be a stronger chelator than chelex resin. This study showed that TPEN would be a stronger chelator compared to DTPA or chelex resin and TPEN and chelex resin exerted cellular zinc depletion to be enough for cell study for Zn depletion.

• Journal of the Korean Ceramic Society
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• v.26 no.5
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• pp.601-608
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• 1989

Electrical properties of ZrF4-based heavy metla fluoride glasses were measured by the ac complex impedance method. The effects of alkali and chloride ions addition into fluoro zirconate glasses on the electrical conductivity were examined. The electrical conductivities of fluoride glasses show Arrhenian behavior in the temperature range of the experiment and were decreased by the addition of sodium fluoride up to 15mol%. Mixed alkali substitution resulted in conductivity minimum at intermediate composition which is commonly observed as mixed alkali effect' in alkali oxide glasses. Chloride ion substituted for fluoride ion was found to lower the conductivity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.236-239
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• 1998

This research was performed to check the transport characteristics of heavy metals in contaminated soil, that is, the influence of humic acid and phosphate on transport characteristics of heavy metals was studied. From the results of column mode experiments about heavy metal behavior, the order time to reach breakthrough and equilibrium was soil ＋ humic acid( 20g ) > soil ＋ humic acid ( 5 g ) > soil without Humic acid addition > soil+humic acid( 50g ). It is because the dissolved organic carbon content increased as the soil organic matter content increased. As the phosphate increased, so did the time to reach breakthrough and equilibrium. The order of time was soil + phosphate( 50 mg ) > soil + phosphate( 20 mg ) > soil . phosphate( 10 mg ) > soil without phosphate addition. It is because the phosphate ion worked as alkalinity donor and the calcium ion co-injected worked as the accelerator of coprecipitation of heavy metals.

• Journal of Forest and Environmental Science
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• v.13 no.1
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• pp.153-165
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• 1997

Hydroxyl radicals were detected and their qualitative yields were estimated by using chemiluminescence method and $\gamma$-irradiation technique in oxygen or chlorine dioxide radicals bleaching conditions. The correlation of hydroxyl radical formation and lignin model(Apocynol) or carbohydrate model($\alpha$-D-glucopyranose and methyl-$\beta$-D-glucopyranoside) degradation was studied in the presence of metal ion or without metal ion. The results showed that the presence of metal ions efficiently affected the formation of hydroxyl radicals in oxygen bleaching process, in the order of $Cu^{2+}$ > $Mn^{2+}$ > $Mg^{2+}$ > $Fe^{2+}$, and these metal gave also rise to the degradation of carbohydrate. But it was found that the addition of $100{\mu}m\;Mg^{2+}$ gave an efficient protection against carbohydrate degradation and suppressed the hydroxyl radical formation under oxygen bleaching conditions. And the presence of $Cu^{2+}$ had a detrimental effect on the stability of carbohydrates, whereas the addition of $3{\mu}m\;Mn^{2+}$ surprisingly had a small protective effect on methyl--$\beta$-D-glucopyranoside. In the $ClO_2$ radical bleaching conditions the hydroxyl radical expected to generate from water or substrates was not detected in the presence of metals.