• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2027-2036
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• 2013

Comparison of removal performance between reverse osmosis(RO), nanofiltration(NF), electrocoagulation(EC) and electroadsorption(EA) for removal of nitrate and fluoride often exceeded the limits of water quality in small water treatment plants. Removals of nitrate and fluoride were 72-92% and 74-85% in RO, 5-15% and 1% in NF, 99% and 44% in EA equipped with MWCNT coated electrodes, 82% and 77% in EA equipped with Cu-MWCNT electrodes, and 11-46% and 69-99% in EC. Consequently, high removals of both ions were anticipated in RO. Effective removal of both ions are possible for EC, but great production of sludge is a big burden. EA equipped with the MWCNT electrodes showed a great fluctuation in removal efficiency, and electrode stability should be upgraded.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.838-846
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• 2016

Most of combustion processess used in industries require recovering or removing flue gas components. Recently a new MBA (moving bed adsorption) process for recovering $CO_2$ using zeolite 13X was developed. In this study, adsorption experiments for carbon dioxide, nitrogen, sulfur dioxide, and water vapor on zeolite 13X were carried out. Adsorption equilibrium and adsorption rate into solid particle were investigated. Langmuir, Toth, and Freundlich isotherm parameters were calculated from the experiment data at various temperatures. Experimental results were consistent with the theoretically predicted values. Also $CO_2$ adsorption amount was measured under the conditions with impurities such as $SO_2$ and $H_2O$. Binary adsorption data were well fitted to the extended Langmuir isotherm using parameters obtained from pure component experiment. However, $H_2O$ impurity less than, roughly, ${\sim}10^{-5}H_2O\;mol/g$ zeolite 13X enhanced slightly $CO_2$ adsorption. Spherical particle diffusion model well described experimentally measured adsorption rate. Diffusion coefficients and activation energies of $CO_2$, $SO_2$, $N_2$, $H_2O$ were obtained. Diffusion coefficients of $CO_2$ and $SO_2$ decreased with small amount of preadsorbed impurity. Parameter values from this study will be helpful to design of real commercial adsorption process.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.63-71
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• 2023

Increased nitrogen in the water system has become an important environmental problem around the world, as it causes eutrophication, algae bloom, and red tide, destroys the water system, and undermines water's self-purification. The most common form of nitrogen in the water system is ammonium ion (NH₄⁺), and the largest portion of ammonium ions comes from wastewater. NH₄⁺ is a major contributor to eutrophication, which calls for appropriate treatment and measures for ammonium removal. This study produced biochar by applying Sorghum × drummondii, a type of biomass with a great growth profile, analyzed the adsorption capacity of Sorghum × drummondii biochar produced from the changing carbonization temperature condition of 200 to 400℃ in the ammonium ion range of 10 to 100 ppm, and used the results to evaluate its potential as an adsorbent. Carbonization decomposed the chemical structure of Sorghum × drummondii and increased the content of carbon and fixed carbon in the biochar. The biochar's pH and electrical conductivity showed high adsorption potential for cations due to electrical conductivity as its pH and electrical conductivity increased along with higher carbonization temperature. Based on the results of an adsorption experiment, the biochar showed 54.5% and 17.4% in the maximum and minimum NH₄-N removal efficiency as the concentration of NH₄-N increased, and higher carbonization temperature facilitated the adsorption of pollutants due to the biochar's increased pores and specific surface area and subsequently improved NH₄-N removal efficiency. FT-IR analysis showed that the overall surface functional groups decreased due to high temperature from carbonization.

• Membrane Journal
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• v.23 no.2
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• pp.159-169
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. The results of water and nitrogen back-flushing were compared in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as increasing HA, Rf increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. Average turbidity treatment efficiencies were almost same independent of HA concentration. Average organic matter treatment efficiency was the minimum 71.4% at 10 mg/L HA in water back-flushing, but those were almost constant in nitrogen back-flushing. The hybrid process of MF, PES beads, and UV (MF + $TiO_2$ + UV) have the lowest $R_f$, and the highest J and $V_T$ in both water and nitrogen back-flushing. The turbidity and organic matter treatment efficiencies were the maximum at MF + $TiO_2$ + UV independent of water and nitrogen back-flushing, and decreased sequently as simplifying the process to MF. However, adsorption performed the more important role than photo-oxidation in water back-flushing, and photo- oxidation was the more than adsorption in nitrogen back-flushing.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.45-45
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• 1999

한국원자력연구소에서 개발중인 KSTAR 중성입자입사 (NBI) 가열장치의 이온원을 시험하기 위한 진공 챔버 (높이 1.2m, 폭 1.2m, 길이 2.4m)의 수소 배기는 저온 흡착 펌프를 제작하여 이용할 계획이다. 흡착제는 활성탄으로 하고, 흡착제의 냉각은 20K 12W Cold Head를 이용한다. 이 흡착제가 부착된 무산소동판을 액체 질소로 냉각된 Chevron Baffle로 열차폐한다. 이 흡착제가 수소를 배기하기 위해서는 15K 이하로 냉각이 되어야 하므로, 이에 대한 열설계가 중요하다. 흡착판에 가해지는 열부하를 평가하고, 이 열부하에서 흡착판 온도가 15K 이하가 되도록 열설계를 수행하였다. 열부하 중 가장 큰 것은 Ghevron을 통해 들어오는 복사열로, Chevron의 복사율 및 난반사도에 따라 MOnte Calro 법 전산코드를 작성하여 복사열을 계산하였다. 크기 500mm x 400mm인 흡착판에 대한 시험 결과를 바탕으로 열설계에 대한 타당성 검증 및 크기 800mm x 1400mm인 흡착판에 대해 열설계 내용에 대해 발표한다.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.127-127
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• 1999

한국원자력연구소에서 개발중인 KSTAR 중성입자입사(NBI) 가열장치의 이온원을 시험하기 위한 진공챔버(높이 1.2m, 폭 1.2m, 길이 2.4m)의 수소 배기는 저온 흡착펌프를 제작하여 이용할 계획이다. 흡착제는 활성탄으로 하고, 흡착제의 냉각은 20K 12W Cold Head를 이용한다. 이 흡착제가 부착된 무산소동판을 액체 질소로 냉각된 Chevron Baffle로 열차폐한다. 이 흡착제가 수소를 배기하기 위해서는 15K 이하로 냉각이 되어야 하므로, 이에 대한 열설계가 중요하다. 흡착판에 가해지는 열부하를 평가하고, 이 열부하에서 흡착판 온도가 15K 이하가 되도록 열설계를 수행하였다. 열부하 중 가장 큰 것은 Chevron을 통해 들어오는 복사열로 Chevron의 복사율 및 난반사도에 따라 Monter Carlo법 전산 코드를 작성하여 복사열을 계산하였다. 크기 500mmx400mm인 흡착판에 대한 시험 결과를 바탕으로 열설계에 대한 타당성 검증 및 크기 800mmx1400mm인 흡착판에 대해 열설계 내용에 대해 발표한다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.246.1-246.1
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• 2010

본 연구는 바이오가스의 에너지효율성을 높이기 위한 연구로서 바이오가스 정제공정과 초저온액화공정을 통하여 액화바이오메탄을 생산하는 바이오가스 고질화기술개발 연구이다. 바이오가스 정제공정은 탈황, 제습, 흡착, 압축, $CO_2/CH_4$ 분리공정으로 구성하고, 초저온액화공정은 열교환기, $CO_2$ 제거설비, 질소냉매 공급공정으로 구성하여 혐기성소화조에서 발생하는 바이오가스($CH_4$ 농도: 60~65%, $H_2S$: 1,500~2,500ppm)를 $200Nm^3/hr$의 유량으로 인입시켜 액화바이오메탄을 생산하였다. 연구결과, 탈황공정에서는 가성소다 세정법을 이용하여 1,500~2,500ppm으로 인입되는 $H_2S$를 100ppm 이하로 제거한 후, 흡착법을 이용하여 $H_2S$를 완전히 제거하였다. 바이오가스에 포화된 수분은 냉각제습과 흡착제습공정을 통해 Dew point $-70{\sim}-90^{\circ}C$까지 제거하여 안정적으로 $CO_2/CH_4$ 분리공정에 인입시켰다. $CO_2/CH_4$ 분리공정은 흡착방식을 적용하여 $CH_4$ 순도가 95% 이상인 바이오메탄을 생산하였으며, 이때 메탄 회수율은 약 87%이였다. $CO_2$가 분리된 바이오메탄은 초저온액화공정을 이용하여 액화바이오메탄으로 전환시켰다. 이때 초저온액화공정은 Reverse Brayton cycle로 구성하였으며, 냉매로는 질소를 사용하였다. 액화바이오메탄의 생산은 바이오메탄을 등엔트로피과정인 단열팽창을 통하여 $-155{\sim}-159^{\circ}C$의 초저온으로 냉각되는 질소냉매와 열교환기에서 열교환시켜 이루어졌으며 그 생산량은 $3.46m^3$/day(1bar, $-161^{\circ}C$)이었다.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.381-388
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• 1984

Addition of heavy textured red earth is being recommended to improve the texture and nutirent retention capacity of sandy soil in Korea. However, farmers are not favorable to this description because of high transportation cost and hard working. To solve this pending problem a field experiment was carried out to investigate the possibility of application of Zeolite as a foreign earth material to improve the physical and chemical characteristics of sandy soil. The experiment results suggested that Zeolite mixed with the basal N fertilizer would be substituted for other foreign earth materials in aspects of rice yield and nitrogen uptake of rice shoot. On the other hand, ammonium adsorption characteristics of soil and amendments were studied.

• 대한공업교육학회지
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• v.32 no.2
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• pp.188-198
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• 2007

Platinum nanoparticles loading on carbon nanotube was carried out by impregnation of hexachloro platinate(IV) from hydrogen hexachloro platinate(IV) hydrate dissolved solution without using reduction agents, and heating the hexachloro platinate(IV) impregnated carbon nanotube up to $400^{\circ}C$. The amounts of impregnated hexachloro platinate(IV) on to carbon nanotube were measured with UV-visible spectrophotometer. The TG, XRD, and TEM analysis were performed to confirm the platinum particles loading and distribution on carbon nanotube. The average platinum particles size on carbon nanotube was under 2 nm by heating the hexachloro platinate(IV) up to $400^{\circ}C$ in spite of non-using reduction agents, while the average size increased due to the agglomeration of some particles by heating them up to $800^{\circ}C$. Therefore, uniformly distributed platinum nanoparticles loading on carbon nanotube can be obtained from simple impregnation of hexachloro platinate(IV) from solution and heating it up to $400^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1141-1145
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• 2005

A contactor coupled sequencing batch reactor composed of pre-anoxic contact zone and intermittently aerated zone was proposed and operated for nitrogen removal. Emphasis was placed on the fact that the contactor can be operated in a rapid reaction mode that results In biological uptake but incomplete metabolism of organic matter. Consequently, 61.2% of the sewage SCOD was adsorbed to activated sludge by 30-minute contact reaction. The specific uptake of organic matter was 22.3 mg SCOD/g MLVSS that enhanced the denitrification efficiency in the following denitrification stage. The removal efficiencies of the organic matter(SCOD) and the total nitrogen(T-N) were 86% and about 60% at the TCOD/TKN ratio as low as 6.0, respectively.