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        검색결과 27

        21.
        2001.08 KCI 등재 서비스 종료(열람 제한)
        A packed bed of volcanic rock was used as deodorizing material to remove hydrogen sulfide(H2S) from air in a laboratory-scale column, and was inoculated with Thiobacillus sp. as H2S oxidizer. The effects of volcanic rock particle size distribution on system pressure drop were examined. Various tests have been conducted to evaluate the effect of H2S inlet concentration and EBCT(Empty Bed Contact Time) on H2S elimination. The pressure drop for particles of size range from 5.6 to 10 ㎜ was 14 ㎜H2O/m at a representative gas velocity of 0.25m/s. Biofilter using scoria and Thiobacillus sp. could get the stable removal efficiencies more than 99.9% under H2S inlet concentrations in the range from 30 to 1,100ppm at a constant gas flow rate of 15.2 ℓ/min. H2S removal efficiencies greater than 99% were observed as long as EBCT was longer than 8sec at the 250ppm of H2S inlet concentration. When EBCT was reduced to 5.5 sec, H2S removal efficiency decreased by about 12 percent. The maximum H2S elimination capacity was determined to be 269g-H2S/㎥·hr.
        22.
        2000.08 KCI 등재 서비스 종료(열람 제한)
        Nitrate-selective ion exchange resin which have bulky tertiary amine as functional group have been synthesized by the reaction of chloromethylated polystyrene-divinylbenzene copolymer and the corresponding tertiary amine [NR3=NEt3 1, N(C2H4OH)3 2] in ethanol, while commercial resin has NMe3 as functional group. The fundamental properties such as bulk density, water content, appearance index, exchange capacity, effective size, uniformity coefficient of synthesized anion exchange resin (1) have been measured. The ion exchange resin (1) and (2) exhibited the better selectivity for nitrate than sulfate in both batch and continuous column experiments.
        23.
        2000.06 KCI 등재 서비스 종료(열람 제한)
        A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k1 was 0.07∼0.17 ℓ/㎎·hr and maximum exchange quantity q0 was 27.75∼31.81 ㎎/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 ㎎/ℓ nitrate-contained wastewater of 10,000 gallons per day to 2 ㎎/ℓ , total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.
        24.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        A kinetic study for anion exchange was performed for commercially available Cl- type anion exchange resin in use to remove nitrate in water. The obtained results from the batch reactor were applied to the Langmuir and Freundlich models. The constants for Langmuir model were qmax=29.82 and b=0.202, and for Freundlich model were K=5.509 and n=1.772. Langmuir model showed better fit than Frendlich model for the experimental results. Ion exchange reaction rate was also calculated and the approximate first-order reaction, rate constant k1 was 0.16 L/㎎·hr. Effective diffusion coefficient was obtained in the range from 9.67×10 exp (-8) to 1.67×10 exp (-6) ㎠/sec for initial concentration change, and from 6.09×10 exp (-7) to 3.98×10 exp (-6) ㎠/sec for reaction temperature change. Activation energy during the diffusion was calculated as 36 ㎉/㏖.
        25.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.
        26.
        1995.12 KCI 등재 서비스 종료(열람 제한)
        The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal of nitrogen and phosphorus compounds under experimental conditions. The recycle ratio of mixed liquor from aerobic to anaerobic region and peak coefficient primarily controlled the extent of nitrogen removal. The recycle ratio had the optimum values which were determined by the microbial activities of nitrification and denitrification. The behavior of the treatment unit could be simulated by using the kinetic equations and reactor models which considered the treatment units as complete mixing tanks.
        27.
        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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