• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.81-84
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• 2004

Control of Sediment is very important in prawn farm due to the eruption of toxic material such as W1ionized H2S, NH3 and NO2-. In this study, column test study, column with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment ammonia-N(NH3) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion(NH4+) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of NH4+, which is not toxic for prawn because oyster shell was stably kept around pH 8. Therefore, some of ammonia(NH3) was reduced by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Korean Journal of Environmental Agriculture
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• v.15 no.2
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• pp.232-238
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• 1996

This study was conducted to find out the optimum condition for $NH_4-N$ removal from wastewater by a zeolite column. The removal efficiency of $NH_4-N$ by a glass column packed with decreased with the increase in initial concentration, percolation velocity and fraction number. The result of multiple stepwise regressions, $NH_4-N$ removal efficiency by the zeolite column showed a high correlationship with various parameters such as percolation velocity, initial concentration, adsorption amount and fraction number. Theoretical formula by parameter coefficients of multiple stepwise regression was found to be $NH_4-N$ removal $efficiency=0.620{\times}amount$ of zeolite $-0.456{\times}percolation$ velocity $-0.212{\times}initial$ concentration $-3.038{\times}fraction$ number+100.1 In the case of the $NH_4-N$ removal efficiency in cattle farming wastewater, the experimental data were nearly coincident with the theoretical formula.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.94-103
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• 2001

SiO$_2$ and PDMS/SiO$_2$ xerogels which are derived PDMS into TEOS have been synthesized by sol-gel process and controlled pore size and distribution through 2 step acid/base catalyzed processes using HCI and NH$_4$OH as a catalyst. In HCl catalyzed SiO$_2$ and PDMS/SiO$_2$ xerogels, pH and gellation time of xerogel were 2.3~2.5 and 12~13 days, respectively, and the shape of xerogel was identified to pellet type and column type. Under acidic condition of final reaction solution, the hydrolysis rate is accelerating, resulting in long gel times. The shape of xerogel is pellet type. In contrast, under less acidic condition, the condensation rate is accelerating, resulting in shorter gel times and the shape of xerogel is column type. The surface area and average Pore size were changed 400$\rightarrow$600($\m^2$/g) and 15$\rightarrow$28$\AA$, respectively, depending to the increase of the mole ratio of HCl/NH$_4$OH, and represented uniform pore size distribution. It is that all the alkoxide groups are hydrolyzed by HCl after the first step and the condensation rate is enhanced by NH$_4$OH. The regular backbone structures of silica are formed at low temperature and the uniform pores are produced by heat treatment.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.240-245
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• 1992

The effect of the addition of sodium dodecyl sulfate (SDS) to a buffered mobile phase (pH 3.4) on the retention of nucleotides, nucleosides and bases was investigated with a polyvinyl alcohol (PVA) column. Depending on the concentration of SDS, two different trends in the retention of nucleosides and bases containing an $NH_2$ group were observed. If the concentration of SDS was less than 5.5 mM, the retention of compounds containing an $NH_2$ group increased as the concentration of SDS in the mobile phase increased. In contrast, if the concentration was greater than 5.5 mM, the retention of compounds containing an $NH_2$ group decreased. Thus, the SDS acted as an ion-pairing reagent at lower concentration but formed micelles at higher concentrations. The retention behavior of the nucleosides and bases in the presence of a micellar concentration of SDS in the mobile phase on the PVA column was compared to the retention behavior on other types of columns.

• Korean Journal of Pharmacognosy
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• v.16 no.3
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• pp.175-179
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• 1985

The optimal condition for the determination of saikosaponin a and d, the major pharmacologically active saponins of the roots of Bupleurum falcatum, was studied with the conversion of these saponins into diene saponins $(saikosaponin\;b_1\;and\;b_2)$. The complete separation and quantitative analysis of these saponins were performed by the method of high performance liquid chromatography using $NH_2$ column. The conversion of saikosaponin a and d into diene saponins under gastric pH was calculated. Thirty-three percent of saikosaponin a was converted to saikosaponin $b_1$ and 63 percent of saikosaponin d was converted to saikosaponin $b_2$.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.63-70
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• 1996

The synthesis of high purity and ultra-fine $BaTiO_3$ by precipitation with gaseous $NH_3$ as precipitator was investigated to find an alternative process to solve various problems of recent wet methods. A synthesis process for $BaTiO_3$ powder using $NH_3$ gas as a precipitator in a bubble column reactor was experimentally successful in developing the production process of piezoelectric ceramic $BaTiO_3$ powder. And a 2.33m1/sec is approprite for the feed flow rate, $BaTiO_3$ powder produced under above the condition is spherical type, its particle size was about $0.2{\mu}m$.

• Journal of environmental and Sanitary engineering
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• v.13 no.1
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• pp.147-156
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• 1998

A synthesis process for PZT powder using $NH_{3}$ gas as a precipitator in a bubble column reactor was experimentally successful in develope a production process of piezoelectric ceramic PZT powder. Also as a reaction by coprecipitation, the crystalized PZT ceramic powder at the condition of over pH 9 could be attained. The time needed for reaction on the condition of $NH_{3}$ gas flow rate = 0.5 1/min, Ar gas flow rate = 2.0 1/min. Feed flow rate = 2.33 ml/sec was less than five minutes, so it could synthesize PZT powder for such a few moments. And the synthesized PZT powder was $0.17{\mu}m$ in diameter on an average.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.69-73
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• 2004

Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.201-208
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• 1992

Municipal landfill leachate, a major source of soil contamination and ground water pollution, causes serious environmental problems. To investigate the removal efficiency of pollutants in the leachate by sand, briquet ash, fly ash, and activated carbon columns, COD and some pollutants in the leachate passed through each column for 8 weeks were examined. Average COD removal efficiency for 8 weeks was 83%, 45%, and 43% by activated carbon, briquet ash and fly ash columns, respectively. COD was not effectively reduced by sand column. Average ${NH_4}\;^+$ removal efficiency for 8 weeks was more than 60% by ail columns. Hardness was effectively removed for 8 weeks by fly ash and activated carbon columns. Anoins including $PO_4\;^{3-}$, $CI^-$ and $SO_4^{2-}$ were not removed by all columns.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.139-148
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• 2015

BACKGROUND: The aim of this study was to isolate and identify algicidal bacterium that tends to kill the toxic dinoflagellate Alexandrium catenella, and to determine the algicidal activity and algicidal range of algicide. METHODS AND RESULTS: Among of algicidal bacteria isolated in this study, NH-3 isolate was the strongest algicidal activity against A. catenella. NH-3 isolate was identified on the basis of biochemical characteristics and analysis of 16S rRNA gene sequences. The NH-3 isolate showed over 99% homology with Arthrobacter oxydans, and was designated as Arthrobacter sp. NH-3. The optimal culture conditions were $25^{\circ}C$, initial pH 7.0, and 2.0% (w/v) NaCl concentration. The algicidal activity of Arthrobacter sp. NH-3 was significantly increased to maximum value in the late of logarithmic phase. Arthrobacter sp. NH-3 showed algicidal activity through indirect attack, which excreted active substance into the culture filtrate. When 10% culture filtrate of NH-3 was applied to A. catenella, 100% of algal cells were destroyed within 30 h. In addition, the algicidal activities were increased in dose and time dependent manners. The pure algicide was isolated from the ethyl acetate extract of the culture filtrate of NH-3 by using silica gel column chromatography and high performance liquid chromatography (HPLC). We investigated the algicidal activity of this algicide on the growth of harmful algal bloom (HAB) species, including A. catenella. As a result, it showed algicidal activity against several HAB species at a concentration of $100{\mu}g/mL$ and had a relatively wide host range. CONCLUSION: Taken together, our results suggest that Arthrobacter sp. NH-3 and its algicide could be a candidate for controlling of toxic and harmful algal blooms.