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        검색결과 1,677

        1622.
        1997.02 KCI 등재 서비스 종료(열람 제한)
        In investigating heavy metal contents at specific areas, the method of selecting sampling points is important. A general method is, according to the law , random sampling of zigzag-form in the selected field. In this work, we studied whether the measured values obtained from a certain method of selecting sampling points is a representative of heavy metal contents in the selected field or not. The selected field for this study is located on the lower Yangsan-river; Gasan-li, Mulgum-myon, Yangsan-gun, KyoungNam. 1 km away from the main stream of Nakdong river. The heavy metals investigated were Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The inductively coupled plasma(ICP) atomic emission spectrometer was used to measure these metals quantitatively. The number of total sampling points were 24. We compared the total mean values with the mean obtained from various methods of selecting sampling points.
        1623.
        1997.02 KCI 등재 서비스 종료(열람 제한)
        Varing the flow velocity of solution and particle diameter, the mass transfer coefficient of the local electrode on current feeder has been measured in an empty flow reactor, an inert fluidized bed electrode reactor, and an active fluidized bed electrode reactor. It had its maximium value when the bed porosity was 0.6 to 0.65 and decreased with increasing the height of local electrode. The mass transfer coefficient was found to be high especially when bigger particle was fluidized. Electrochemical deposition of copper dissolved in the synthesized wastewater has been performed in the active fluidized bed electrode reactor. The deduction rate was higher than 90% and the residual concentration of copper decreased to less than 5ppm.
        1625.
        1996.12 KCI 등재 서비스 종료(열람 제한)
        We investigated concentrations of heavy metals(Cr, Cd, Zn, Fe, Pb, Cu, and Mn) and correlations between concentrations of heavy metals in the sediment, soil, weeds, and vegetables on the lower Nakdong river. Concentrations of heavy metals on the lower Milyang river was generally lower than those of other sampling area. In the soil, concentration of Pb is generally larger than that of other heavy metals. Generally, concentrations of heavy metals in the sediment show decreasing tendency as the sampling area moves toward downstream of the river, but those of in the soil and weeds show increasing tendency. There is no significant correlation between concentration of heavy metals in the soil-sediment, soil-vegetables, sediment-weeds, or vegetables-weeds. Only concentrations of Pb in the vegetables and those of in the weeds show very high correlation.
        1626.
        1996.12 KCI 등재 서비스 종료(열람 제한)
        The incineration tests of mixed industrial wastes using the stoker type incinerator are carried out to investigate the partitioning characteristics of heavy metals during incineration. The results obtained from this study are as follow. The partitioning characteristics of heavy metals throughout this incinerator are found that, at given condition of 700℃, the elements with the relatively high boiling point such as Cr, Cu and Pb are partitioned into a bottom ash, a fly ash captured by cyclone, and a flue gas stream, 67∼88%, 2∼19% and 6∼16% of initial amount entering the incinerator, respectively, but the Cd and Hg of 75∼81% is vaporized into the flue gas. It appears that the partitioning characteristics according to the particle size of ash is different between the bottom ash and the fly ash. For bottom ash, the fraction of partitioning into 75㎛ oversized particles is relatively high. For fly ash, the characteristics of distributions with the particle size can not be clearly shown.
        1627.
        1996.12 KCI 등재 서비스 종료(열람 제한)
        Cation exchange distribution coefficients of poly(dithiocarbamate) were presented for Cd^2+, Cr^3+, and Pb^2+ in HCl. The distribution coefficients were determined by using the batch method. Based on these distribution data, the separation possibilities of the heavy metal ions were discussed. The distribution coefficients of three heavy metal ions on dithiocarbamate resin were decreased as HCl concentrations were increased. The selective separation of Cr^3+ and Cd^2+ was possible by using 0.1 M HCl in dithiocarbamate resin and the reproducibility test showed that the average absorptivity of resin was 90% in the case of Cd^2+ ion by the column method.
        1628.
        1996.12 KCI 등재 서비스 종료(열람 제한)
        The removal effectiveness of various heavy metal ions in boron-rich containing plants has been studied by means of spectroscopic and pH methods. Treatment of the boron-rich containing sample which was collected from cherry and root of cabbage to heavy metal ions is resulted in that an excellent removal effect shows in the case of large ionic size of heavy metal. Stability constants are depended on the variation of pH.
        1631.
        1996.10 KCI 등재 서비스 종료(열람 제한)
        This study is involved to develop new catalysts to decompose plastics, detergents and surfactants containing synthetic peptide bonds. As the first year research, the catalytic hydrolysis of amide bond in copper complex was accomplished. The hydrolysis reaction in aqueous solution was monitored by UV/VIS spectroscopy. As the pH of the solution is increased and the temperature is raised, the reaction rate increases. The reaction rate is observed as the first order kinetic behavior for the copper complex. The metal catalyzed hydrolysis mechanism is proposed via metal-hydroxide in the pH region of 5.5 to 6.3. The results of characterization of the catalytic reaction mechanism can be applied to develop new catalysts for peptide bond degradation in further research.
        1632.
        1996.08 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to evaluate the level of atmospheric heavy metals and the relationship of that concentration with weather conditions. This research monitored the concentration of Total Suspended Particulates (TSP) at every three hours by using High Volume Air Sampler from December 24th, of 1995 to Febuary 20th, 1996 in Kimhae area, which recently became a rapidly growing residential and industrial sitc. The items such as air-temperature, relative humidity, radition, wind speed, and wind direction were monitored by using Atmospheric Weather System at the same time. From the collected TSP, the concentration of heavy metals were analyzed by using the Atomic Absorption Spcetrophotometry. The mean concentration of TSP was 110.4 ㎍/㎥, and the mean concentration of lead (Pb), copper (Cu), chromium (Cr), manganese (Mn), cadmium (Cd), were 0.837 ㎍/㎥, 0.486 ㎍/㎥, 0.264 ㎍/㎥, 0.157 ㎍/㎥, 0.054 ㎍/㎥, respectively. Regarding daily variations, the concentration of TSP was highest in the morning (158.1 ㎍/㎥) followed by evening (119.4 ㎍/㎥) and afternoon (111.1 ㎍/㎥). The concentration of Pb and Mn was higher in the morning, and that of Cu, Cr and Cd was higher in the afternoon and the evening. Regarding the relationship between the concentration of pollutants and weather condition, the concentration TSP revealed positive correlation with temperature, humidity, wind speed, but negative correlation with radition (p<0.01). The concentration of Mn revealed positive correlation with temperature and humidity, but negative correlation with wind speed (p<0.01). And the the concentration of pollutants and weather condition revealed higher correlation within the same time period. In summary, the paralleled mornitoring of air conditions and weather condition should be recommended to get the correct informations concerning the pollution and to prevent the deterioration of air conditions.
        1638.
        1996.04 KCI 등재 서비스 종료(열람 제한)
        This study was conducted for the efficient utilization of a scoria, which is abundantly found in Cheju island, as adsorbent and the scoria was examined for its performance in clarification of adsorption of heavy metal ions. The order in heavy metal ions adsorbed on scoria was; Pb^+>Cd^2+>Cu^2+>Ag^+>Co^2+>Zn^2+>Cr^3+>Cr^6+. This tendency was relatively consistent with the decreasing order of radius of hydrated metal ion. Also, the smaller scoria size and the larger amounts of scoria showed higher removal efficiency for heavy metal ions. The same scoria size showed more effective removal efficiency for heavy metal ions at lower initial concentration than at higher initial concentration. The adsorption abilities of original scoria and chemically treated scoria were compared. Adsorption isotherm of scoria was generally obeyed to Freundlich formula than Langmuir formula and Freundlich constant, 1/n was obtained in the range of 0.2∼0.4.
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