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        검색결과 8

        2.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 질소산화물 제거용 환원제로 사용하는 요소 수용액을 암모니아로 전환하는데 있어 SCR 상용촉매의 활용가능성을 확인하기위해 촉매조성에 따른 반응온도, 공간속도의 영향에 대한 연구를 수행하였다. 연구결과 SCR 촉매로 널리 사용되는 V2O5/TiO2 촉매는 TiO2 및 WO3-V2O5/TiO2 촉매에 비해 암모니아 생성이 우수함을 보였다. 활성금속을 담지하지 않은 TiO2 촉매는 V2O5 혹은 WO3-V2O5를 담지 한 촉매에 비해 공간속도에 따른 암모니아 전환에 영향을 받지 않는 것으로 나타났으며, 활성금속을 담지 한 촉매는 공간속도가 증가함에 따라 암모니아 생성 농도가 감소됨을 확인하였다.
        4,000원
        3.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The experiment was performed using the cleaning precipitator To investigate the absorption efficiency of the SOX/NOX of the aqueous ammonia solution. Concentration of the cleaning liquid is 0.1, 0.5, and 1.0% with increasing absorption efficiency has improved. However, the reaction shown only a difference in time. Absorption efficiency has improved in accordance with the gas residence time. When the direction of the same gas and the cleaning liquid is determined that there is the effect of increasing the residence time. The relative impact of SOX and NOX is this likely to react slower than SOX/NOX. The yield is determined to require
        4,000원
        4.
        2012.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In order to enhance the selective adsorption of CO2, the surface of granular activated carbon (GAC) was modified by an ammonia solution. Ammonia in an aqueous phase could be decomposed into NH4+, OH- and other N-containing elements. The present work attempted to impregnate some basic functional groups leading to chemisorption of the activated carbon surface. While the addition of N-groups reduced the specific surface area from 2071.4 m2/g to about 1300-1400 m2/g, the adsorption capacity for CO2 increased to a certain degree, and the best amination could be achieved with the reaction at 100℃ for 12 hours. The enhanced adsorption capacity could be obtained by formation of nitrogen functionalities such as amine, pyrrolic groups and pyridine oxides which were verified by XPS analysis.
        4,000원
        5.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nickel powders were synthesized by the hydrazine reduction of nickel chloride solution containing ammonia in DEA solutions. The size distribution of nickel powders were investigated as a function of ammonia concentration, hydrazine concentration and the mixed composition ratio of diethanolammine (DEA) and triethanolammine (TEA). Nickel powders with the size in submicron range were obtained at for 45 minutes by hydrazine reduction of nickel chloride solution in DEA solutions. The hydrazine concentrations showed significant effects on the particle size and shape distribution of nickel powders under molar ratio of 2.0 condition. As the mixed volume ratio of TEA and DEA increased, nickel powders with relatively larger particle size and low agglomeration were obtained. Nickel powders with particle size in the ranged from 0.4 to were obtained at the 50 of TEA.
        4,000원
        6.
        2014.07 KCI 등재 서비스 종료(열람 제한)
        This research investigated the feasibility of rice husk as a biosorbent for removal of ammonium ion from aqueous solutions. To improve the sorption functionality of rice husk, the carboxyl groups were chemically bound to the surface of the rice husk by graft polymerization of acrylic acid using potassium peroxydisulphate as a redox initiator. The removal of ammonium ion by rice husk grafted with acrylic acid (RH-g-AA) was studied in a batch mode and fixed bed columns. The kinetic and equilibrium data obtained from batch experiments follow the second-order kinetics and fit well with the Langmuir isotherm model. The sorption energy determined from D-R model was 8.61 kJ/mol indicating an ion-exchange process as the primary sorption mechanism. To determine the characteristic parameters of the column useful for process design, four mathematical models; Bed Depth Service Time (BDST), Bohart-Adams, Clark and Wolborska models were applied to experimental data obtained from the fixed bed columns with varying bed heights. All models were found to be suitable for simulating the whole or a definite part of breakthrough curves, but the Wolborska model was the best. The fixed bed sorption capacity determined from the Wolborska model was in the range 33.3 ~ 40.5 mg/g close to the value determined in the batch process. The thickness of mass-transfer zone was calculated to be approximately 40 mm from DBST model. The RH-g-AA sorbent could be regenerated by a simple acid washing process without a serious lowering the sorption capacity or physical durability.
        7.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        저 품위 엽납석 광석에 포함된 불순물 Fe를 제거하기 위하여 입도크기, 황산농도, 황산암모늄농도, 과산화수소농도 그리고 온도변화에 따른 제거 효율에 대하여 연구하였다. 저 품위 엽납석 광석에서 자형의 입방체 황철석이 포함된 것을 반사현미경으로 관찰할 수 있었으며, X-선 회절분석결과 주 구성광물은 석영과 딕카이트였다. 실험 결과 Fe 용출율이 최대로 나타나는 입도 -325 mesh에서, 황산농도는 2.0 M에서, 황산암모늄 농도는 10.0 g/l, 과산화수소 농도 3.0 M 그리고 최적의 용출 온도는 70℃에서였다. 용해 동역학 분석에서, Fe 용해는 황철석 표면에서 일어나며 화학적 반응에 통제되는 것으로 그리고 0.066/R, [H2SO4]1.156, [(NH4)2SO4]0.745, [H2O2]0.428 에 비례하는 것으로 나타났다.
        8.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        황철석 시료로부터 Fe를 효과적으로 용출시키기 위하여 마이크로웨이브 에너지와 암모니아 용액을 적용하였다. 황철석을 마이크로웨이브에 60분 동안 노출시키자 적철석과 자류철석으로 상변환되었다. 그리고 암모니아 용액에 의하여 Fe가 최대로 용출되는 마이크웨이브 노출시간은 60분이였다. Fe 용출율이 99% 이상으로 나타나는 시료와 마이크로웨이브 노출 조건은 325-400 mesh의 황철석 시료와 60분에서였다. 그리고 암모니아 용출 조건은 0.3 M의 황산, 2.0 M의 황산암모늄 그리고 0.1 M의 과산화수소 농도에서였다. 고체-잔류물에 대하여 XRD 분석을 수행한 결과 황철석, 적철석 그리고 자류철석은 암모니아 용액에 의하여 완전히 제거되었지만 석영은 제거되지 않았다.