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        검색결과 44

        41.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        Removal of Cu(Ⅱ), Cr(Ⅱ) and Pb(Ⅲ) ions from aqueous solutions using the adsorption process on the loesses has been investigated. Variations of contact time, pH, adsorption isotherms and selectivity of coexisting ions were experimental parameters. pH of KJ and YIK samples diluted to 1% solution, was rearly the same with each value of pH 5.58 and 5.49, and both samples showed weak acidic properties. From chemical analysis, both samples contain remarkably different amounts of SiO2, Al2O3 and Fe2O3. From XRD measurement, quartz was mainly observed in both samples. Kaolinite was also observed, also in both samples, but Feldspar was only observed in KJ sample. Adsorption of metal ions on the loesses were reached at equilibrium by shaking for about 30min. The adsorption of Cr(Ⅲ) ion was higher than that of Cu(Ⅱ) and Pb(Ⅱ) ions. The order of amount adsorbed among the investigated ions was Cr(Ⅲ)>Pb(Ⅱ)>Cu(Ⅱ). In acidic solution, the adsorptivity of loesses was increased as pH increased. The adsorption of Cr(Ⅲ) ion on the loesses were fitted to the Freundlich isotherms. Freundlich constants(l/n) of KJ and YIK loesses were 0.54 and 0.55, respectively.
        42.
        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.
        43.
        1995.06 KCI 등재 서비스 종료(열람 제한)
        New two macrocyclic compounds using as carriers of liquid emulsion menbrame, have been synthesized. These reuslts provide evidance for the usefulness of the theory in designing the systems. The efficiency of selective transport for heavy metal ions have been discussed from the membrane systems that make use of SCN^- I^- , CN^- and Cl^- ion as co-anions in source phase and make use of S_2O_3^2- and P_2O_7^4- ion as receiving phase, respectively. The transport, rate of M(Ⅱ) was highest when a maximum amount of the M(Ⅱ) in the source phase was present as Cd(SCN)_2([SCN^-]=0.40M, Hg(SCN)_2([SCN^-]=0.40M) and Pb(CN)_2([CN^-]=0.40M). The Cd(Ⅱ) and Pb(Ⅱ) over each competitive cations were well transprted with 0.3M-S_2O_3^2- and 0.3M-P20_7^4 , respectively in the receiving phase. Results of this study indicate that two criteria must be met in order to have effective macrocycle-mediated transport in these emulsion system. First one must effective extraction of the M^n+ into the toluene systems. The effectiveness of this extraction is the greatest if logK for M^n+-macrocycle interaction is large and if the macrocycle is very insoluble in the aqueous phase. Second, the ratio of the logK values for M^n+-receiving phase (S_2O_3^2- or P_2O_7^4-) to M^n+-macrocycle (L_1 or L_2) interaction must be large enough to ensure quantitative stripping of M^n+(Cd^2+, Hg^2+ or Pb^2+) at the toluene receiving phase interface. L_1(3.5-benzo-10,13,18,21-tetraoxa-1,7,diazabicyclo(8,5,5) eicosan) forms a stable Cd^2+ and Pb^2+ complexes and L_1 is very insoluble in water and its Cd2^+ and Pb^2+ complex is considerably less stable than Cd^2+-(S_2O_3)_2^2- and Pb^2+-P_2O_7^4- complexe is On the other hand, the stability of the Hg^2+-L_1 complex exceed that of the Hg^2+-(S_2O_3)_2^2- and Hg^2+-P_2O_7^4- , and the distribution coefficient of L_2(5,8,15,18,23,26-hexaoxa-1,12- diazabicyclo-(10,8,8) octacosane) is much smaller than that of L_1. Therefore, the partitioning of L_2 is favored by the aqueous receiving phase, and little heavy metal ions transport is seen despite the large logK for Hg^2+-L_1 and M^n+(Cd^2+, Pb^2+ and Hg^2+)-L_2 interactions.
        44.
        1993.12 KCI 등재 서비스 종료(열람 제한)
        This study was conducted for the efficient utilization of biomaterials such as starch residue, tangerine skin, and green tea residue, which are agricultral by-products discarded in Cheju Province annually, as adsorbents and biomaterials were examined for their removal ability of heavy metal ions in waste water by batch adsorption experiments. The removal efficiency of biomaterials for heavy metal ions was above 80-90% and almost similar to activated carbon and the adsorption ability of those treated with 포르말린 was improved in the green tea residue only for Pb^2+, Cu^2+, and Zn^2+. In the conditions of pH, the removal efficiency of heavy metal ions was high in the range of 5-7. In the solutions which heavy metal ions were mixed, the removal efficiency was similar at Ag^+, Pb^2+ and reduced to about 10% at the other ions, as compared with the solutions they were not mixed. Adsorption isotherms of biomaterials was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, 1/n were obtained in the range of 0.1-0.5.
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