• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1495-1500
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• 2014

Two new complexes with 5-methyl-1-(pyridine-3-yl)-1H-1,2,3-triazole-4-carboxylic acid (Hmptc) ligand: [$Cd(mptc)_2(H_2O)_4$] (1) and $[Cu(mptc)_4{\cdot}2H_2O]_n$ (2) were prepared and their crystal structures were determined by single crystal X-ray diffraction analyses. In complex 1, the Cd(II) ions coordinates with the pyridyl nitogen atom from the Hmptc ligand, forming a mononuclear Cd(II) compound. Complex 2 exhibits a novel two-dimensional (2D) polymer in which four Hmptc ligands stabilize the Cu(II) atom. And the coordination involves one nitrogen atom of the triazole, one oxygen atom of the carboxylic acid and the pyridyl nitrogen atom. In addition, FT-IR and solid-state fluorescent emission spectroscopy of two compounds have been determined.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.561-567
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• 1993

The twelve macrocycle (L) complexes of cadmium(II) nitrate have been synthesized: $CdL(NO_3)_2$. All the complexes have been indentified by elemental analysis, electric conductivity measurements, IR and NMR spectroscopic techniques. The molar electric conductivities of the complexes in water and acetonitrile solvent were in the range of 236.8-296.1 $cm^2{\cdot}mol^{-1}{\cdot}ohm^{-1}$ at 25$^{\circ}$C. The characteristic peaks of macrocycles affected from Cd(II) were shifted to lower frequencies as compared with uncomplexed macrocycles. A complex with 1,4,8,11-tetrakis(methylacetato)-1,4,8,11-tetraaza cyclodecane (L4) exhibited two characteristic bands such as strong stretching (1646 $cm^{-1})$, and weaker symmetric stretching band (1384 $cm^{-1})$. NMR studies indicated that all nitrogen donor atoms of macrocycles have greater affinity to cadmium(II) metal ion than do the oxygen atoms. The $^{13}$C-resonance lines of methylene groups neighboring the donor atom such as N and S were shifted to a direction of high magnetic field and the order of chemical shifts were $L_1 < L_2 < L_3 < L_6 < L_4$. Also the chemical shifts values were larger than those of methylene groups bridgeheaded in side-armed groups. This result seems due to not only the strong interaction of Cd(Ⅱ) with nitrogen donors according to the HSAB theory, but weak interaction of Cd(Ⅱ) and COO- ions or sulfur which is enhanced by the flexible methylene spacing group in side-armed groups. Thus, each additional gem-methyl pairs of L_3, L_4\;and\; L_6$ macrocycles relative to $L_1, L_2,\;and\;L_5$ leads to an large enhancement in Cd(II) affinity. ^{13}C$-NMR spectrum of the complex with $L_{12}$ (1,5,9,13-tetracyclothiacyclohexadecane-3,11-diol) reveals the presence of two sets of three resonance lines, and intensities of the each resonance line have the ratio of 1 : 2 : 2. This molecular conformation is predicted as structure of tetragonal complex to be formed by coordinating two sulfur atoms and the other two sulfur atoms which is affected by OH-groups.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.640-648
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• 2023

The purpose of this study was to determine the inhibitory effect of heavy metals [Cd(II), Ni(II), and Zn(II)] on the growth of Rhodobacter species (Rhodobacter blasticus, Rhodobacter sphaeroides, and Rhodobacter capsulatus) and their potential use for Cd(II), Ni(II), and Zn(II) bioremoval from liquid media. The presence of toxic heavy metals prolonged the lag phase in growth and reduced biomass growth for all three Rhodobacter species at concentrations of Cd, Ni, and Zn above 10 mg/L. However, all three Rhodobacter species also had a relatively high specific growth rate against each toxic heavy metal stress test for concentrations below 20 mg/L and possessed a potential bioaccumulation ability. The removal efficiency by all strains was highest for Cd(II), followed by Ni(II), and lowest for Zn(II), with the removal efficiency of Cd(II) by Rhodobacter species being 66% or more. Among the three strains, R. blasticus showed a higher removal efficiency of Cd(II) and Ni(II) than R. capsulatus and R. sphaeroides. Results also suggest that the bio-removal processes of toxic heavy metal ions by Rhodobacter species involve both bioaccumulation (intracellular uptake) and biosorption (surface binding).

• Journal of Preventive Medicine and Public Health
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• v.22 no.2 s.26
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• pp.215-222
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• 1989

The relationship between cadmium level and mental retardation was investigated. The 297 subjects with mental retardation were drawn from two schools providing special educational services, one, consisted of children living in an orphan home, another, children with parents. The 117 control subjects were drawn from whom had got average or above average academic achivement in a general elementary school. Hair sample was taken from the nape of the neck and the cadmium and zinc analysis were carried out on an atomic absorption spectrophotometer (IL 551). Children in the retarded group had significantly higher cadmium levels compared with control but not in zinc levels. There was no relationship between metal concentrations and age except control male group, which showed significant positive linear relationship in zinc, and there was no difference between sex in both metal except the male orphan group in cadmium. In the orphan group, there was relationship between severity of retardation and cadmium concentration in both sex but not in retarded children with parents. No difference in cadmium levels between the group with Down's syndrome, one of causes of mental retardation, and the control group suggested the cadmium as a possible cause of mental retardation. In the case of accompanying autism, zinc level was significantly lower than that of other accompanying diseases. Although not establishing an etiologic relationship, findings of this study suggest that there are some influeces of cadmium on mental retardation, and call for a continuing study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.113-117
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• 1979

The short-term acute toxicities of mercury, cadmium and copper for the clam, Meretrix lusoria were determined from 28 June to 15 July, 1978. In the test with mercury and copper, the rate ot mucus excretion increased gradually at a higher concentration. But the clams did not excrete mucus in the solutions of cadmium and natural sea water. The rate of mucus excretion in mercury was $42.9\%$, and that in copper was $14.3\%$ in a test solution of 1mg/l. mercury was more toxic than copper. The median lethal concentration after 96 hours (96 hr-Lc 50) was 0.67mg/l in mercury, 7.04mg/l in copper and 7.10mg/l in cadmium. Consequently it was found that mercury was the most toxic substance and cadmium was the least. meanwhile, it was considered that exposure time by stimulation in a fixed concentration caused the test animals to respond.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1375-1382
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• 2007

A column preconcentration method with pulverized Amberlite XAD-4 loaded with bismuthiol I (BI) has been developed for the determination of trace Cd(II) and Cu(II) in various real samples by flame atomic absorption spectrophotometry. Various experimental conditions, such as the size of XAD-4, adsorption flow rate, amount of bismuthiol I, stirring time for adsorbing bismuthiol I on XAD-4, pH of sample solution, amount of XAD-4- BI, desorption solvent, and desorption flow rate, were optimized. Also, the adsorption capacity and the adsorption rate of Cd(II) and Cu(II) on XAD-4-BI were investigated. The interfering effects of various concomitant ions were investigated, Bi(III), Sn(II) and Fe(III) were found to affect the determination. But the interference by these ions was completely eliminated by adjusting the amount of XAD-4-BI resin to 0.70 g, although the adsorption flow rate was slower. For Cd(II) our proposed technique obtained a dynamic range of 0.5-40 ng mL-1, a correlation coefficient (R2) of 0.9913, and a detection limit of 0.3 ng mL-1. For Cu(II), the corresponding values were 2.0-120 ng mL-1, 0.9921 and 1.02 ng mL-1. To validate this proposed technique, the aqueous samples (stream water, reservoir water, tap water and wastewater), the diluted brass sample and the plastic sample, as real samples, were used. Recovery yields of 91-103% were obtained. These measured data were not different from ICP-MS data at 95% confidence level. Our proposed method was also validated using rice flour CRM (normal, fortified) samples. From the results of our experiment, we found that the technique we present here can be applied to the determination of Cd(II) and Cu(II) in various real samples.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.17-35
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• 2001

In this study, we conducted a combined adsorption-sequential extraction analysis(CASA) to investigate temperature effects of single adsorption of lead, copper, zinc and cadmium on natural clays. As a result, it was found that in a single adsorption of lead and copper, about 50% of adsorption was occluded in carbonate phase, and in case of cadmium, about 80% of adsorption was occluded in exchangeable phase. At temperature below $25^{\circ}C$ about 60% of zinc was occluded in exchangeable phase but above $40^{\circ}C$ about 50% of zinc was occluded in carbonate phase. The effect of temperature on each occluded phase was largely observed in Fe-oxide, Mn-oxide and organic occluded phases. Besides, the adsorption of metals on natural clays was an endothermic reaction with the exception of exchangeable phase adsorption.

• Membrane and Water Treatment
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• v.4 no.1
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• pp.11-25
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• 2013

Emulsion liquid membrane (ELM) process suffers from emulsion instability problem. So far, emulsion produced by mechanical methods such as stirrer and homogenizer has big size and high emulsion breakage. This paper discussed the application of emulsion produced by sonicator to extract cadmium in a batch ELM system. The emulsions consist of N,N-Dioctyl-1-octanamine (trioctylamine/TOA), nitrogen trihydride (ammonia/NH4OH), sorbitan monooleate (Span 80), and kerosene as carrier, stripping solution, emulsifying agent, and organic diluent, respectively. Effects of comprehensive parameters on extraction efficiency of Cd(II) such as emulsification time, extraction time, stirring speed, surfactant concentration, initial feed phase concentration, carrier concentration, volume ratio of the emulsion to feed phase, and pH of initial feed phase were evaluated. The results showed that extraction efficiencies of Cd(II) greater than 98% could be obtained under the following conditions: 15 minutes of emulsification time, 4 wt.% of Span 80 concentration, 4 wt.% of TOA concentration, 15 minutes of extraction time, 250 rpm of stirring speed, 100 ppm of initial feed concentration, volume ratio of emulsion to feed phase of 1:5, and initial feed pH of 1.53.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.14-22
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• 2004

The effect of cadmium ions on ligninolytic and decolourizing activities in cultures of two white-rot fungi, Cerrena unicolor and Trametes versicolor, were examined. Cadmium was added to the shallow stationary cultures growing on a liquid mineral medium. Both examined strains sorbed Cd ions in the first 24 hr of incubation. An appreciable stimulation of the activity of extracellular laccase (LAC) and inhibition of the extracellular manganese-dependent peroxidase (MnP) were simultaneously observed when 25 mgL^-1 and 50 mgL^-1 of cadmium ions were added to the cultures. On the other hand, the addition of cadmium ions also resulted in stimulating the decolorization activity of C. unicolor to decolorize Remazol Brilliant Blue R (RBBR) in the cultures, but decreasing it in the culture of T. versicolor, which is compared to the inhibition of MnP activity in this fungus. Our data indicate that the presence of Cd(II) ions can affect the ligninolytic activity of white-rot fungi. It was found that C. unicolor is a strain resistant to the presence of Cd ions in the liquid culture media, and has a potential to use this strain for bioremediation of sites contaminated with both heavy metals and aromatic pollutants.