• Resources Recycling
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• v.24 no.6
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• pp.9-16
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• 2015

In a recycling scheme of spent lithium ion batteries, a co-precipitation process for the re-synthesis of precursor is essential after the leaching of lithium ion battery scraps. In this study, the effect of ammonia as impurity during the co-precipitation process was investigated in order to re-synthesize a precursor of Ni-rich cathode active material $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ (NCM 622). As ammonia concentration increases from 1 M (the optimum condition for synthesis of the precursors based on 2 M of metal salt solution) to 4 M, the composition of obtained precursors deviates from the designed composition, most notably for Ni. The Ni co-precipitation efficiency gradually decreases from 100% to 87% when the concentration of ammonia solution increases from 1 M to 4 M. Meanwhile, the morphological properties of the obtained precursors such as sphericity, homogeneity and size distribution of particles were also investigated.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.321-327
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• 2013

In the present work, the reactors that harbor bacterial biofilms including ammonia-oxidizing bacteria (AOB) and heterotrophic bacteria were treated with a continuous dose of chlorite ($0.66{\pm}0.01mg/L$) either with or without monochloramine at $1.77{\pm}0.03mg/L$. Both chlorite alone and combined chlorite-monochloramine applications effectively reduced biofilm and bulk AOB levels to near or below the detection limit ($0.6MPN/cm^2$ and 0.2 MPN/ml). The combined chlorite-monochloramine application exhibited greater AOB inactivation than chlorite alone. Unlike AOB, heterotrophic plate count (HPC) was unaffected by chlorite alone. In contrast to chlorite-only application, a combination of chlorite and monochloramine resulted in a significant reduction in HPC levels with log reductions of 3.1 and 3.0 for biofilm and bulk water, respectively. The results demonstrate that the combined chlorite-monochloramine application can provide an effective treatment for the inhibition of AOB and heterotrophic bacteria in a drinking water distribution system.

• Polymer(Korea)
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• v.25 no.5
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• pp.635-641
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• 2001

$\beta$-Cyclodextrine/benzoic acid complex was prepared and reacted with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine). Identification of complex formation and reaction was checked by FT-IR, UV-Vis, and EDX. By reacting this material with cotton fiber, the deodourant fiber was prepared. The deodourizing property was evaluated by the concentration changes of aqueous ammonia solution after flowing ammonia gas through the column titled with deodourant fiber prepared. The deodourizing property was increased with an increase of concentration of $\beta$-cyclodextrine unit in the fiber. In the case of $\beta$-cyclodextrine/benzoic acid complex, the deodourzing property was much increased, comparing with the $\beta$-cyclodextrine only. It was considered to be the binding of aamonia gas caused by benzoic acid in the complex.

• KSBB Journal
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• v.14 no.3
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• pp.358-364
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• 1999

The effect of hydrogen peroxide on pretreatment of oakwood was investigated. Reaction temperature was $170^{\circ}C$ and reaction solutions used in pretreatment were aqueous ammonia, sulfuric acid and pure water. When 10% ammonia solution was used, the extents of delignification and hemicellulose recovery were 55% and 26%, respectively. These values were significantly higher as delinigfication and lower as hemicellulose recovery than those of acid hydrolysis. To overcome this problem, hydrogen peroxide was added into ammonia solution stream to increase hemicellulose recovery. But delignification and hemicellulose recovery were not increased as much as hydrogen peroxide loading was increased. And as hydrogen peroxide loading was increased, the decomposition of sugars solubilized from hemicellulose and cellulose were increased. So there were significant differences between the total amount in solid residue and liquid hydrolyzate, and the total amount in the original biomass. It was found that hydrogen peroxide added was reacted with substrate packed mostly in the front part of reactor. In order to increase hemicellulose recovery, it was necessary to treat with acidic solution than with alkali solution. Effect of hydrogen peroxide was higher in water than acid solution.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.663-672
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• 1990

The extraction of ginseng saponins with near critical or supercritical ammonia(SCF-NH$_3$) was carried out at 80$^{\circ}C$-160$^{\circ}C$ and ammonia densities of 339.8-525 $mg/cm^3$. In order to evaluate brownish color of white ginseng extracts, a spetrophotometric method was applied in ultraviolet and visible range. The extractibilities of ginseonoside $Rb_1$, -$Rb_2$, -Rc, -Rd, -Re, -Rf, $-Rg_1$, and $-Rg_2$ were determined by high performance liquid choromatography. The best extractability was 7.36% at 133$^{\circ}C$ and 403 $\pm$ 24.605 $mg/cm^3$. In the case of the high extraction temperature, it is thought that extraction times can be reduced and the selectivity of protopanaxatriol can be increased. The brownish color of extracts is affected by temperature and extractability. When extraction temperature is between 132$^{\circ}C$ and 140$^{\circ}C$, it is shown that the range is the retrograde region where extractablility decrease with increasing temperature.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.188-188
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.329-330
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• 2003

우리나라의 경우, 생활문화 수준의 향상과 소득 증대에 따라 물 소비량이 증가하고 있으며, 이러한 물 소비량의 증가는 필연적으로 다량의 하수를 배출하게 되었고, 하수에 의한 수질오염을 방지하기 위하여 정부에서는 하수처리장 건설을 적극 추진하고 있는 실정이다. 2000년 현재 전국의 하수처리장은 172개소이며 처리 용량은 18,399.83 천ton/일이며, 하수처리율은 70%에 달하고 있다. 정부에서는 하수처리율을 2005년까지 85%로 높이기 위한 계획을 수립ㆍ추진 중에 있다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.235-236
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• 2000

최근 경제 성장과 더불어 고단백, 저지방 식품인 어류의 수요가 증대되고 있으며, 특히 횟감용 활어의 소비량이 급증하고 있다. 반면 해수의 수급이 용이하지 않은 내륙지방의 경우 활어수조 내 해수의 오염도가 높아 어류의 폐사가 발생하며, 이로 인해 국민건강에 영향을 미친다. 활어 수조 내에서 발생되는 어류의 배설물 중 단백질 성분은 미생물에 의해 분해되어 암모니아를 발생시키고 용존산소를 감소시키는 물질로서 신속한 제거가 필요하다(서 등, 1999). (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.326-327
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• 2001

양어장 내에서 발생되는 어류의 배설물 중 단백질 성분은 미생물에 의해 분해되어 암모니아를 발생시키고 용존산소를 감소시키는 물질인 반면 소수기와 친수기를 함께 가지는 구조적 특성으로 인해 계면활성제 역할을 하여 별도의 계면활성제를 첨가하지 않아도 포말분리를 수행 할 수 있도록 해줌으로, 포말분리에 의한 양어장 순화수 중 어류에 유해한 성분의 처리수단으로써 많이 연구, 적용되어지고 있다. (중략)

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.1-7
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• 2020

The synthesis and catalytic activities over vanadium carbides were examined for ammonia decomposition reaction to produce the hydrogen. In particular, the comparison of vanadium nitrides were made on the ammonia decomposition reaction. The experimental data exhibited that BET surface areas ranged from 5.2 ㎡/g to 25.6 ㎡/g and oxygen uptake values varied from 3.8 μmol/g to 31.3 μmol/g. It is general that vanadium carbides (VC) were observed to be superior to vanadium nitrides for ammonia decomposition reaction. The primary reason for these differences were thought to be related to the extent of electronegativity between these materials. Most of vanadium carbide crystallites were exceeded by Pt/C crystallite. We assumed that the activities for vanadium carbide crystallites (VC) were comparable to or even higher than that determined for the Pt/C crystallite.