• Elastomers and Composites
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• 제33권3호
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• pp.177-184
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• 1998

Polytetramethylene ether glycol(PTMG)와 4,4'-diphenylmethane diisocyanate(MDI), tol-uene 2,4-diisocyanate (TDI), isophoron diisocyanate(IPDI)로 polyurethane(PU) prepolymer를 합성, n-methyl-diethanol amine(n-MDEA)로 쇄연장시킨 후 glycolic acid(GA)로 quaternization시켜서 안정한 수분산성의 양이온성 폴리우레탄을 제조하였다. 양이온성 폴리우레탄의 합성과정에서 쇄연장제의 함량과 quaternization에 따른 에멀젼의 유화안정성, 접착강도, 점도, 유리전이온도 및 cast film의 물리적 성질을 UTM, Viscometer와 DSC를 사용하여 검토하였다.

• 상하수도학회지
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• 제7권1호
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• pp.20-28
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• 1993

The Wastewater from the weight reduction process of polyester is more difficult to be treated biologically than the general wastewater from dyeing and finishing processes in textile industries. Above wastewater shows high pH, high organic strength and wide variation of organic loading. These characteristics are due to TPA and EG resulting from alkaline weight-reduction process and make trouble in the operation of activated sludge process. Therefore, the objective of this study is to develop the pretreatment method for the successful operation of treatment process. For the successful pretreatment process, the wastewater from weight-reduction process should be segregated from other wastewater stream and then acidified with concentrated sulfuric acid to precipitate out TPA from DST solution. At the optimum pH of 2. 2, the initial $COD_{cr}$ 60,000mg/l is reduced to 11,500mg/l and the removal efficiency of $COD_{cr}$ is 81.1%. The required amount of sulfuric acid for pretreatment is not greater than the amount for the the existing neutralization process. Moreover, the supernatant of pretreatment process can be reused in acidification of wastewater.

• 펄프종이기술
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• 제47권3호
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• pp.11-17
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• 2015

In acid hydrolysis process of biomass saccharification. neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Kluyveromyces marxianus in glucose solution was investigated focused on ethanol fermentation. Either potassium or sodium cations decreased the ethanol fermentation and glucose to ethanol conversion. Glucose consumption by K. marxianus was delayed by increasing potassium cation concentration as completely consumed within 12 h in potassium cation 0.46 mol and 0.92 mol but within 24 h in potassium cation 1.38 mol. Also, ethanol fermentation process was slowed down with increasing concentration of the potassium sulfate. Fermentation of glucose solution to ethanol was more inhibited by sodium cation than potassium cation in glucose solution. Glucose was completely consumed within 24 h in sodium cation 0.95 mol. but at 1.90 mol or 2.84 mol in sodium cation could not finish the fermentation within 48 hour. Ethanol concentration was 22.26 g/L at low sodium cation in glucose solution with complete fermentation within 24 h. With increasing sodium cation in glucose solution, final ethanol concentration was reached at 14.10 g/L (sodium cation con) and 0.21 g/L (sodium cation con), which meant delaying of fermentation by sodium cations.

• 상하수도학회지
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• 제19권2호
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• pp.125-134
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• 2005

Waste concrete powder was used to remove fluoride ions in highly concentrated fluoride wastewater. 92.6% of fluoride in 100 mg F/L wastewater was removed by 1% dose of the cement paste powder that represents characteristics of waste concrete powder, whereas the removal efficiencies of raw cement and lime were 47.3% and 96.4%, respectively. The cement paste powder was competitive to lime, common fluoride removal agent. Various Ca-bearing hydrates such as portlandite, calcium silicate hydrate, and ettringite in cement paste slurry can remove fluoride by precipitating $CaF_2$ and absorbing $F^-$ ions. In the experiments using both cement paste and lime, 50~67% of lime can be substituted by cement paste to satisfy fluoride effluent limitation of 15 mg/L. Since cement paste has higher acid neutralization capacity than lime, it can be recycled to neutralize more acid and to remove more fluoride. Therefore waste concrete powder can be more economical and viable alternative for lime in fluoride wastewater treatment.

• 방사성폐기물학회지
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• 제22권2호
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• pp.159-171
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• 2024

This study aimed to develop an efficient recycling process for wastewater generated from soil-washing used to remediate uranium (U(VI))-contaminated soil. Under acidic conditions, U(VI) ions leached from the soil were precipitated and separated through neutralization using hydrazine (N₂H₄). N₂H₄, employed as a pH adjuster, was decomposed into nitrogen gas (N₂), water (H₂O), and hydrogen ions (H⁺) by hydrogen peroxide (H₂O₂). The residual N₂H₄ was precipitated when the pH was adjusted using sulfuric acid (H₂SO₄) to recycle the wastewater in the soil-washing process. This purified wastewater was reused in the soil-washing process for a total of ten cycles. The results confirmed that the soil-washing performance for U(VI)-contaminated soil was maintained when using recycled wastewater. All in all, this study proposes an efficient recycling process for wastewater generated during the remediation of U(VI)-contaminated soil.

• 한국토양비료학회지
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• 제40권2호
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• pp.151-155
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• 2007

수원지역에서 영농기간 중 강우의 화학적 특성을 알아보기 위하여 2005년 4월부터 10월까지 39점의 빗물을 채수하여 pH 및 화학적 성분조성을 조사하였다. 강우량을 고려한 가중평균(volume-weighted mean) 이온농도 변화와 알카리성 물질들에 의한 빗물의 산성도 중화를 평가한 결과는 다음과 같다. 시료분석의 신뢰성을 검토한 이온균형과 전기전도도 수지 평가에서는 각각 높은 상관을 나타내어 분석 이온들에 대한 신뢰가 인정되었다. 조사기간 동안 빗물의 pH 분포는 pH 4.5~5.6 범위가 많았으며, 월별로는 6월이 다른 조사기간에 비해 높았다. 강우량와 빗물의 EC 관계에서는 강우량이 증가한 5월 이후 낮은 EC값을 보이다가 강우량이 적었던 10월부터 다시 증가하는 경향을 보였다. 빗물의 조성에서 양이온 구성은 $Na^+$ > $NH^{4+}$, $Ca^{2+}$, $H^+$ > $K^+$ > $Mg^{2+}$의 순이었으며, $Na^+$, $NH_4{^+}$, $Ca^{2+}$ 및 $H^+$가 전체 양이온 함량의 93% 이상을 차지하였다. 음이온은 $SO{_4}^{2-}$ > $NO_3{^-}$ > $Cl^-$ 순으로 $SO{_4}^{2-}$ 및 $NO_3{^-}$가 약 86%를 차지하였다. 조사기간 중 강우 산성도 중화는 6월이 다른 기간에 비해 높았음을 보였다. 총 sulfate 함량 중 nss-$SO{_4}^{2-}$ 함량은 88%로 빗물중에 함유된 sulfate의 대부분이 인위적인 발생원에서 기인되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.415-418
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• 2005

Nowadays the three major commercially available of organic chemical admixtures are modified lignosulfonates(LS), sulfonated naphthalene-formaldehyde resins (SNF) and sulfonated melamine-formaldehye (SMF). In this study, various sulfonated melamine-formaldehyde (SMF) superplasticizers were synthesized via four synthetic steps. Hydroxymethylation (Step 1), Sulfonation (Step 2), Polymerization (Step 3) and Neutralization and Stabilization (Step 4). In this synthesis of SMF, reaction conditions such as the mole ratio of melamine to formaldehyde and the amount of acid catalyst were changed. After application of SMF superplasticizer to cement paste and mortar, the physical properties including workability, slump loss, compressive strength were compared.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1996년도 추계 학술발표회
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• pp.468-472
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• 1996

A series of UV-curable polyurethane acrylate ionomer were synthesized from isophorone diisocyanate(IPDI), poly(tetramethylene ether glycol)(PTMG), 2,2-bis(hydroxymethyl)propionic acid (CMPA), triethylamine(TEA), 2-hydroxy ethyl acrylate (HEA), and dibutyl tin dilaurate (DBT) as a catalyst. 2,2-dimethoxy-2-phenyl acetophenone(DMPAP) was used as a photoinitiator. The films of UV-cured polyurethane acylate ionomer were prepared by casting the formulated materials onto a glass plate at room temperature and cured using a medium pressure mercury lamp (80 W/cm, max = 365nm). Effects of DMPA content, molecular weight of PTMG and degree of neutralization on the properties were invesigated. It is found that the storage modulus increased with increasing DMPA content. The glass transition temperature of sample A shifted to higher temperature as the content of DMPA was increased. Tensile modulus also increased with increasing DMPA content. Modulus and Tg decreased with increasing molecular weight of PTMG form 650 to 2000. With increasing the degree of nutralizaion, ionomers exhibited improved modulu.

• 한국표면공학회지
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• 제19권1호
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• pp.13-19
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• 1986

Manganese in the Anode slime and the paste-positive material of waste-dry cell was recovered by leaching with the hydrochloric acid solution. The impurities (Zn, Fe, Pb), co-leached with manganese were removed from the leached solution prior to electrolysis by hydrometallurgical techniques such as the neutralization with ammonium hydroxide and cementation on manganese powder. The electrodeposition of manganese from the purified chloride solution with sodium selenate was performed. Cathode current efficiency was found to be affected significantly by the concentration of sodium selenate and ammonium chloride salt, bath temperate, current density and PH. The current efficiency of about 88.7% was obtained by electrolysis manganese chloride solution with sodium selenate (0.1/g) at 10$^{\circ}C$.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권3호
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• pp.16-23
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• 2005

중금속과 황산이온의 농도가 높은 산성광산배수(AMD)를 배출하는 강원도 정선군에 위치한 삼척탄좌 정암광업소 유출수를 대상으로 제강 슬래그, 우분 및 석회석 등을 활용하여 처리실험을 수행하였다. Batch test와 적용성 시험 결과, 원수 1 L당 15 g의 제강 슬래그, 15 g의 우분 및 500 g의 석회석이 최적의 기질물질 양으로 조사되었다. 이를 기초로 제강 슬래그, 우분과 석회석으로 충진한 SAPS조, 침전조, 산화조 순서로 구성된 처리시스템을 구성하였다. 총 54일간 시행된 실험결과, 원수에 비해 pH의 상승(3.0에서 8.3)과 더불어 61%의 황산염이온 농도가 저감되었다 (1,042 mg/L에서 409 mg/L). 또한, 초기농도 대비 최종 방류수의 중금속 처리효율은 매우 높은 수준으로써 99.9% 이상의 Al, Fe, Zn과 92.6% Mn이 제거되었다. 즉, 제강 슬래그, 우분 및 석회석을 활용하면 산성광산수의 중화와 금속 침전효과를 얻을 수 있음을 확인하였다.