• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.682-684
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• 2009

본 논문에서는 해수 중에 존재하는 염분을 제거하기 위하여 가스하이드레이트 형성 원리를 이용하였다. 하이드레이트 형성을 위한 guest molecule는 이산화탄소를 사용하였으며, host moelcule로는 3.5% NaCl 물을 사용하였다. 염수에 강한 반응기를 만들기 위하여 스테인레스 강에 epoxy 수지를 코팅하여 실험을 수행하였다. 실험한 결과 70% 이상의 염제거율을 얻을 수 있었으며, 2단 공정이나 3단 공정을 적용할 경우 더욱 높은 염제거율을 얻을 수 있을 것이라고 판단된다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.38-40
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• 2003

$TiO_2$로 코팅된 scoria를 이용하여 공존물질 존재시 humic acid의 광분해 연구 결과 광촉매량의 증가에 따라 제거효율이 증가하였고, 양이온을 첨가하였을 때 제거효율이 증가하였다. 탄산염이온을 첨가하였을때는 상당한 차이를 보였으며 180분 후에도 30%정도의 제거 효율을 나타냈다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1298-1304
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• 2005

This study was performed to evaluate the characteristics of the competition between two electron acceptors, perchlorate and nitrate, with Citrobacter Amalonaticus strain JB101. In addition, the applicability of membrane bioreactor(MBR) for perchlorate removal was evaluated. The maximum growth rate of strain JB101 on perchlorate and nitrate are 0.27 and 0.58 $hr^{-1}$, and maximum substrate utilization rates were 35.1 mg $ClO_4^-/g$ protein-day and 45.6 mg $NO_3^-/g$ protein-day, respectively. Nitrate was a competitive inhibitor for perchlorate, and strain JB101 prefer nitrate to perchlorate as electron acceptor. Complete removal of perchlorate could be achieved up to the surface leading rate of 4.6 g $ClO_4^-/m^2-day$ with the MBR fed with 20 mg $ClO_4^-/L$(HCMBR). When 5 mg/L of nitrate was added to the same influent, perchlorate removal efficiency decreased to 96.5%, while nitrate was completely removed. For the MBR fed with 0.7 mg/L of perchlorate (LCMBR), the maximum perchlorate removal efficiency was 100% up to the loading rate of 0.23 g $ClO_4^-/m^2-day$. Membrane fouling was found to be a problem at high leading rate for both MBRs. The acetate consumption ratio per perchlorate was $13.7{\sim}51.7\;e^-eq./e^-eq.$ in LCMBR, while the value was $2.5{\sim}3.6\;e^-eq./e^-eq.$ in HCMBR. This difference could be related to the acetate consumption with oxygen as electron acceptor. Therefore, the amount of acetate addition must be determined considering the concentrations of other electron acceptors in the influent.

• Membrane Journal
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• v.28 no.5
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• pp.332-339
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• 2018

In order to investigate the effect of ion exchange capacity of ion exchange membranes on the salt removal efficiency in the membrane capacitive deionization process, sulfosuccinic acid (SSA) as the cross linking agent was added to poly(vinyl alcohol)(PVA) and sulfonic acid-co-maleic acid (PSSA_MA) was put into PVA at different concentrations of 10, 50 and 90 wt% relative to PVA. As the content of PSSA_MA increased, the water content and ion exchange capacity increased and the salt removal efficiency was also increased in the membrane capacitive deionization process. The highest salt removal efficiency was 65.5% at 100 mg/L NaCl feed at a flow rate, 15 mL/min and adsorption, 1.4 V/5 min for PSSA_MA 90 wt%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1198-1205
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• 2000

In this paper, we introduce a modified interference cancellation scheme to overcome MAI in DS-CDMA. Among ICs(Interference Cancellers), PIC(Parallel IC) requires the more complexity, and SIC(Successive IC) faces the problems of the long delay time. Most of all, the adaptive detector achieves the good BER performance using the adaptive Inter conducted iteration algorithm. So it requires many iterations. To resolve the problems of them, we propose an improved adaptive detector that the received signal removed MAI through the sorting scheme and the cancellation method are fed into the adaptive filter. Because the improved input signal is fed into the adaptive filter, it has the same BER performance only using smaller iterations than the conventional adaptive detector, and the proposed detector having adaptive filter requires less complexity than the other detectors.

• Journal of Conservation Science
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• v.27 no.4
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• pp.441-450
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• 2011

This study investigated potential damages and conservation methods for the ceramics (without glaze) by examination of physical and chemical effects from the burial environments. For this study, pottery samples excavated from Daejeon Hakha, Asan Eumbong, Hwasung Sogeunsan and Kongju Haengbokdosi were examined with released ions and extraction through desalination. The result showed that the ion inflow into the ceramics was dependent upon the porosity and the absorption of ceramics. The high temperature fired ceramics (over $1,000^{\circ}C$) have low porosity and absorption, therefore almost no salt infiltration during the burial period. However, low temperature fired ceramics (under $800^{\circ}C$) have high porosity and absorption, and most of salts were removed during the desalination. The 40 to 60% of salts were removed in two days and 60 to 80% of slats were released in a week. Furthermore, fertilizer residues such as $K_2SO_4$, in soils were detected in the ceramcis. Also the characteristics of buried soil affected ion infiltration into ceramics. Ceramics buried in sandy soil had relatively less ion contents from buried environments than those in clayey soil. Therefore, low temperature fired ceramics could do not only cleaning but also desalination if it is necessary, and the period could be decided to the condition of ceramics.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.1-3
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• 1997

질산염(NO$_3$)은 음전하를 띠고 있기 때문에 지하에서 제거되기 어려운 물질 중 하나이다. 특히, 매립지로부터 침출수로 유출될 경우 통제하기가 곤란하다. 본 연구에서는 제철폐기물로서 다량 발생하는 제강슬러지와 제강슬래그를 매립지 복토/차수재로 이용시 NO$_3$흡착 제거 가능성을 알아보기 위해 온도, pH, 초기농도를 변화시키는 회분식방법의 실험을 실시하였다. 온도와 PH는 낮을 때. 초기농도는 높을 때 높은 흡착제거 효율을 나타내었다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.11
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• pp.642-648
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• 2015

Oak wood based activated carbon was modified with surface impregnation of $Fe^{3+}$ and $Al^{3+}$ metal ions mixture for enhancements of phosphate adsorption capacity in aqueous solution. The phosphate adsorption capacity of the prepared metal impregnated carbon (MC) was about 8 times higher than that of the original activated carbon (OC). Adsorption equilibrium capacities of the phosphate increased with increasing system temperature. The adsorption equilibrium isotherm of phosphate on the prepared MC could be represented by the Langmuir equation. Thermodynamic parameters also indicated that adsorption system was spontaneous and endothermic reaction. The internal diffusion coefficient was measured to analyze the adsorption behavior and kinetic rate. To determine the internal diffusion coefficient, pore diffusion model (PDM) was employed and the result was in good agreement with experimental data.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.345-345
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• 2009

전기화학적 환원 기술을 이용한 고온 용융염 전해환원의 결과 생산되는 금속전환체는 다공성 특성에 의해 전해환원의 매질인 용융염을 함유하게 된다. 전해환원과 후속 전기화학 공정인 전해정련의 전해질은 각각 LiCl과 LiCl-KCl 공융염으로 상이하기 때문에 이렇게 금속전환체에 포함된 LiCl 염이 동반되어 전해정련 공정에 도입될 경우 전해정련 공정의 공융염 조성을 어긋나게 한다. 이에 따라 금속전환체의 잔류염은 효과적으로 제거되어야 하며 공정으로 감압 증류에 의한 잔류염 제거 공정이 고려되고 있다. LiCl은 증기압이 비교적 낮기 때문에 감압의 고온 조건이 공정에 필요하다. 그러나 상평형도 분석 결과 전해환원 공정에서 산화물을 담아 음극으로 사용되어 환원된 금속전환체와 함께 도입되는 SUS 재질의 바스켓과 사용후핵연료 금속전환체의 주된 원소인 우라늄과는 공융할 수 있기 때문에 LiCl 증발 온도는 $720^{\circ}C$ 이하로 유지되어야 한다. 이와 같은 조건에서 LiCl 증발 속도를 높이기 위해서는 감압 조건이 필수적이다. 본 연구에서는 감압조건에서 LiCl 휘발 실험을 위해 폐쇄형 및 개방형 반응기를 제작하여 압력 조건 및 Ar 유량 등에 따른 LiCl 휘발율을 측정하였다. 증발된 LiCl은 일정 감압 조건에서 분말형으로 냉각부위에 회수 될 수 있었으나 완전 진공 조건에서는 결정형으로 냉각 부위에 응축되는 것으로 확인 되었으며 일정 진공 조건에서는 Ar 유량에 따라 증발량이 의존하지 않는 것으로 나타났다. 연구 결과 증발염의 취급 빛 이송을 위해 분말형 회수를 목표로 설정할 수 있었으며 공정조건으로 일정 수준의 감압 조건을 제시하였다. 이 후 후속 연구로 장치의 대형화 및 증발 속도 향상을 위한 추가적인 연구가 계획되어 있으며 연구 결과에 기초하여 공학규모 파이로 공정 시설인 PRIDE에 도입될 장치의 기초 설계 자료를 생산할 예정이다.

• Membrane Journal
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• v.30 no.5
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• pp.350-358
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• 2020

A membrane capacitive deionization (MCDI) cell is constructed by applying thin layer of a cation exchange membrane (Nafion) on cathode and an anion exchange membrane (aminated polyphenylene oxide, APPO) on anode. Compared to CDI cell without CEM and AEM coating, MCDI exhibits enhanced salt removal efficiency. When Nafion and APPO are used as CEM and AEM, optimized salt removal performance as high as 82.1% is observed when 1.2 V is applied for 3 min during absorption process and -1.0 V is applied for 1 min during desorption.