• Journal of Applied Biological Chemistry
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• v.42 no.1
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• pp.25-28
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• 1999

For investigating the effectiveness of Korean natural zeolite for removal of $NH_4{^+}$ in waste waters containing $NH_4{^+}$ and $Cu^{2+}$, the adsorption of $NH_4{^+}$ and $Cu^{2+}$ by three Korean natural zeolite samples, which contained mordenite and/or clinoptilolite, was measured by adding solutions containing $NH_4{^+}$ and $Cu^{2+}$ or both at a concentration range from 1 to 7 mmol(+)/L of each cation. In the solutions, the zeolite samples adsorbed more amounts of $NH_4{^+}$ than $Cu^{2+}$. By seven successive equilibrations, Korean natural zeolites adsorbed $NH_4{^+}$ corresponding to 23~33% of those cation exchange capacity from the solution containing both $NH_4{^+}$ and $Cu^{2+}$ at 3 mmol(+)/L of each cation. Whereas, the corresponding adsorption of $Cu^{2+}$ was 17-27% of the CEC. Korean natural zeolite exhibited selectivity for $NH_4{^+}$ but not for $Cu^{2+}$. Nevertheless, it using as a soil amendment after removing of $NH_4{^+}$ in waste waters should be carefully controlled on the application rate.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.135-141
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• 2014

$NH_3$-SCR has high NOx removal efficiency approximately 80~90%. Recently, the copper or iron ion-exchanged zeolite catalysts are widely used as automobile SCR catalysts. In this paper, the effect of the space velocity, temperature of reaction and $NO_2$ addition on the $NH_3$-SCR reaction were studied using various zeolite SCR catalysts. The test was conducted with small sized fresh catalysts in a laboratory fixed-bed flow reactor system using simulated gases. It is found that the activity of the BEA is better than MFI. It seems that three-dimensional framework and a wide pore entrance of BEA enhances the SCR activity. It is also found that low temperature activity of Cu-zeolites was better than Fe-zeolites. Once $NO_2$ was added, the NOx conversion activity of the Cu-zeolite was slightly enhanced, whereas remarkable improvement was achieved by Fe-zeolite.

• Ocean and Polar Research
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• v.23 no.4
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• pp.379-388
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• 2001

Ch1 a abundance, Ch1 a-specific productivity and phytoplankton growth rate in each size fraction (pico, $<2{\mu}m$; nano, $2-10{\mu}m$; micro, > $10{\mu}m$) in the waters around the South Shetland Islands (Ant-arctic Peninsula Area) were analysed. Although Ch1 a-specific productivity and growth rate were highest in micro-size fractions, ChI a abundance was highest in pico-size fractions. Selective removal of nano- and micro-size phytoplankton especially by krill and salp grazing, but not limitation of phytoplankton growth, seemed to be the major reason to explain this miss match between productivity and abundance of the phytoplankton community.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.95-96
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• 2006

CMOS Image Sensor(CIS) 소자에서 광감도의 향상과 천연색 형성을 위하여 적용하고 있는 Color-Filter 공정에서 국부적으로 발생하는 strip성 불량과 막질손상을 제거하기 위한 연구를 진행하였다. 우선 지역적 경향성을 보이는 불량에 대해서는 PR strip process type을 액조 진행방식에서 회전식으로 변경했을 때 제거됨을 확인하였고, 막질손상을 최소화하기 위해서는 새로운 유기용매의 적용이 필요하였다. 실험 결과, 케톤기를 가지는 화합물과 Polar Apotic 용매의 혼합화합물을 적용하였을 때 각 막질에 attack을 최소화하면서 원하는 PR만 선택적으로 제거 되며 미세잔류성분에 대한 제거력도 향상됨을 확인하였다.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.131-143
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• 2018

Phosphorus (P) is a limited, essential, and irreplaceable nutrient for the biological activity of all the living organisms. Sewage sludge ash (SSA) is one of the most important secondary P resources due to its high P content. The SSA has been intensively investigated to recover P by wet chemicals (acid or alkali). Even though $H_2SO_4$ was mainly used to extract P because of its low cost and accessibility, the formation of $CaSO_4$ (gypsum) hinders its use. Heavy metals in the SSA also cause a significant problem in P recovery since fertilizer needs to meet government standards for human health. Therefore, P recovery process with selective heavy metal removal needs to be developed. In this paper some of the most advanced P recovery processes have been introduced and discussed their technical characteristics. The results showed that further research is needed to identify the chemical mechanisms of P transformation in the recovery process and to increase P recovery efficiency and the yields.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1179-1180
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• 2005

To immobilize the pollutants from wastewater in situ, two phosphatic clays collected from different areas in Egypt (eastern and western Sebaia, Aswan-Isna, Upper Egypt) used to remove contaminant ions from industrial wastewater. Obtained results confirmed the strong relationship between phosphatic clay and Pb elimination from wastewater. The sensitivity classification of phosphatic clay toward ions retained as described in three categories: highly sensitive to retain Pb , Al and Cr ; moderately sensitive for Mn; and weakly sensitive for Band Zn. Data suggested that large fraction of Pb removed by phosphatic clays stayed intact under a wide variation in extracting solution pH (3-11). In situ immobilization is considered a promising technique that has the potential to remove contaminant ions from wastewater. Two important factors need to be considered when applying this technique: The first, is the clay must be effective and selective under different composition of wastewater. The second, is the immobilized ions should be stable and non-leacheable under varying water conditions. Phosphatic clays with $Pb^{2+}$ were suitable to achieve these two factors. Possible mechanism for removal $Pb^{2+}$ by phosphatic clays is the formation of fluoropyromorphite through the dissolution of fluoro and hydroxyl apatite by its precipitation from solution, beside, Pb complexation at phosphatic clay surface at P-OH sites.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.82-86
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• 1998

The maltose binding protein (MBP) fusion protein system is a versatile tool to express and isolate recombinant proteins in E. coli. In this system, MBP fusion proteins are efficiently isolated from whole cell lysate using amylose conjugated agarose beads and then eluted by competition with free maltose. Since MBP is a rather large molecule (∼42 kDa), for further experiments, the MBP part is usually proteolytically cleaved from the fusion protein and subsequently removed by ion-exchange chromatography or rebinding to amylose columns after washing out excess and MBP-bound maltose. In the present study, we have developed an improved method for the removal of cleaved MBP, which is advantageous over conventional methods. In this method, factor Xa cleaved MBP fusion proteins were incubated with Sepharose beads conjugated with MBP specific monoclonal antibodies and then precipitated buy centrifugation, resulting in highly purified proteins in the supernatant.

• Carbon letters
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• v.3 no.1
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• pp.6-12
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• 2002

A study on the electrosorption of $Co^{2+}$ and $Sr^{2+}$ ions onto a porous activated carbon fiber (ACF) was performed to treat radioactive liquid wastes resulting from chemical or electrochemical decontamination and to regenerate the spent carbon electrode. The result of batch electrosorption experiments showed that applied negative potential increased adsorption kinetics and capacity in comparison with open-circuit potential (OCP) adsorption for $Co^{2+}$ and $Sr^{2+}$ ions. The adsorbed $Co^{2+}$ and $Sr^{2+}$ ions are released from the carbon fiber by applying a positive potential on the electrode, showing the reversibility of the sorption process. The possibility of application of the electrosorption technique to the separation of radionuclides was examined. The result of a selective removal experiments of a single component from a mixed solution showed that perfect separation of $Co^{2+}$ and $Sr^{2+}$ ions was possible by the electrosorption process.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.832-838
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• 2003

IMO NOx levels are generally possible to meet by means of primary on-engine measures. Nevertheless further significant follow-on reductions are likely to require a secondary after-treatment technique. SCR system is currently the only available technology proven at full scale to meet the 90% NOx reduction levels. Accordingly, maybe the use of an SCR system on board ship provides the solution to minimize this primary pollutant without increasing fuel consumption. In order to develop a practical SCR system for marine application on board ship, a primary SCR system using urea was made. The SCR system was set up on the ship. employed a two-stroke diesel engine as a main propulsion. which is a training ship in KMU (Korea Maritime Univ.). The purpose of this paper is to report the results about the basic effects of the above system parameters which is investigated from practical application through its trial use. The degree of NOx removal depends on some parameters. such as the amount of urea solution added, space velocity. reaction gas temperature and activity of catalyst. The preliminary results from trial run are presented.

• Journal of the Korean Chemical Society
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• v.61 no.5
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• pp.231-237
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• 2017

Efficiently removing Al(III) from rare earth is very significant because even trace amount of Al(III) can cause serious harm to the rare earth materials. In this paper, a nitrogen-containing activated carbon, AC-P700, was synthesized using peas as raw materials. The AC-P700 was characterized by surface area analyzer, FT-IR, and XPS methods. The adsorption and recognition properties of AC-P700 towards Al(III) were investigated, and the recognition mechanism was also analyzed. The BET special surface area of AC-P700 was $1277.1m^2{\cdot}g^{-1}$, and the average pore diameter was 1.90 nm. The AC-P700 possesses strong adsorption affinity and excellent recognition selectivity towards Al(III). The adsorption capacity for Al(III) could reach to $0.53mmol{\cdot}g^{-1}$, and relative selectivity coefficients relative to La(III) and Ce(III) is 9.6 and 8.7, respectively. Besides, AC-P700 possesses better regeneration ability and reusability.