석탄회를 NaOH로 용융시킨 후 수열 처리에 의하여 제올라이트 A를 합성하였다. NaOH/석탄회의 비, 용융 온도, NaAlO2의 첨가량, 수열 처리 온도 및 시간이 생성된 제올라이트의 종류와 결정도에 미치는 영향에 대하여 연구하였다. 결정도가 높은 제올라이트의 생성에 필요한 최적의 NaOH/석탄회의 중량비는 1.2, 최적의 용융 온도는 550℃이었다. 용융된 석탄회로부터 Si4+ 와 Al3+의 용출은 교반 시간의 영향을 받지 않았다. 생성된 제올라이트의 형태는 첨가한 NaAlO2의 영향을 받는 것으로 나타났다. 적은 양의 NaAlO2를 첨가하면 제올라이트 X가 생성되나 NaAlO2의 양이 증가하면 단일상의 제올라이트 A가 생성되었다. 수열처리 시간과 온도가 증가하면 제올라이트 A는 hydroxysodalite로 변화하였다. 승온 속도를 낮춰 반응 온도까지의 도달시간을 증가시키면 결정도가 좋은 제올라이트 A를 얻을 수 있었다.

클로알칼리(CA) 멤브레인법은 이온전도성 고분자전해질을 이용한 염수전기분해공정을 의미하며, 전통적으로는 가성소다와 염소 생산을 목적으로 하고 있다. CA 멤브레인법은 기존 클로알칼리 공정으로 사용되어왔던 수은법 및 격막법에 비해 환경적 유해성이 낮으며, 에너지비용을 상당히 감소시킬 수 있다는 장점을 나타낸다. 본 총설에서는 멤브레인법의 기본개념 및 특징, 핵심기술에 관한 내용을 다루고자 한다. 또한 높은 에너지비용을 갖는 염수전기분해에 대한 에너지 절감효과를 달성하기 위한 시스템 집적화기술, 산소탈분극전극 기술과 이종 기술과의 하이브리드를 통한 고도 CA 시스템기술의 예로서의 이산화탄소 직접전환기술에 대해 논할 것이다. 마지막으로, 멤브레인법에 기반한 국내외 CA 기술동향을 소개할 것이다.

고로슬래그는 유동성 장기강도 및 내구성이 좋고 수화열을 낮아 경화체를 제조함에 따른 적용성이 우수하지만, 몇 가지 문제점을 갖는다. 시공시간이 증가하고 회전속도가 늦고 초기강도가 낮다. 본 연구에서는 알칼리활성화를 이용한 경화체 제조에 있어 필요한 알칼리 수용액을 해수담수화 과정에서 발생하는 농축수의 전기분해를 통하여 공급하였으며. 알칼리 수용액을 이용하여 고로슬래그와 경화체를 제작하였다. 결과는 다음과 같이 요약할 수 있다 : 모르타르의 압축강도는 NaOH 2%이하일 때는 감소하고, 6% 이하까지는 증가한다. 그리고 NaOCl의 함량이 증가할수록 압축강도도 증가한다. 그러나 NaCl이 모르타르에 존재하면 초기강도보다 재령 28일차 강도는 감소하게 된다.

The Chlor-alkali (CA) process is a representative electrolysis system to produce valued chemicals such as chlorine gas and sodium hydroxide. Membrane cell process has been obtaining the largest market shares, because it is free from environmental issues and low chemicals purity. For the CA process, commercially available membrane materials are perfluorinated sulfonic acid ionomers (PFSAs) with high chemical resistance. Unfortunately, there are limited data associated with the relationships between membrane material parameters and CA performances. It prevents the CA membrane development to be difficult. In this study, the influences of PFSA membrane thickness are disclosed, considering their ion transport behaviors, gas evolution capability, and chemical/electrochemical resistances under CA operation conditions.

PURPOSES: In this study, alkali-activated blast-furnace slag (AABFS) was investigated to determine its capacity to absorb carbon dioxide and to demonstrate the feasibility of its use as an alternative to ordinary Portland cement (OPC). In addition, this study was performed to evaluate the influence of the alkali-activator concentration on the absorption capacity and physicochemical characteristics. METHODS: To determine the characteristics of the AABFS as a function of the activator concentration, blast-furnace slag was activated by using calcium hydroxide at mass ratios ranging from 6 to 24%. The AABFS pastes were used to evaluate the carbon dioxide absorption capacity and rate, while the OPC paste was tested under the same conditions for comparison. The changes in the surface morphology and chemical composition before and after the carbon dioxide absorption were analyzed by using SEM and XRF. RESULTS: At an activator concentration of 24%, the AABFS absorbed approximately 42g of carbon dioxide per mass of paste. Meanwhile, the amount of carbon dioxide absorbed onto the OPC was minimal at the same activator concentration, indicating that the AABFS actively absorbed carbon dioxide as a result of the carbonation reaction on its surface. However, the carbon dioxide absorption capacity and rate decreased as the activator concentration increased, because a high concentration of the activator promoted a hydration reaction and formed a dense internal structure, which was confirmed by SEM analysis. The results of the XRF analyses showed that the CaO ratio increased after the carbon dioxide absorption. CONCLUSIONS : The experimental results confirmed that the AABFS was capable of absorbing large amounts of carbon dioxide, suggesting that it can be used as a dry absorbent for carbon capture and sequestration and as a feasible alternative to OPC. In the formation of AABFS, the activator concentration affected the hydration reaction and changed the surface and internal structure, resulting in changes to the carbon dioxide absorption capacity and rate. Accordingly, the activator ratio should be carefully selected to enhance not only the carbon capture capacity but also the physicochemical characteristics of the geopolymer.

PURPOSES: This paper describes the expansion caused by the alkali-aggregate reaction (AAR) in concrete pavement currently in service. It also discusses the effects of joints installed to release the stress induced by the AAR expansion. METHODS: The expansion effect on concrete pavement was verified by a visual inspection and long-term measurement of the joint width of a cut-section. The behaviors of 16 newly installed joints were monitored as part of the investigation and long-term monitoring was carried out for three years after cutting. RESULTS: The behavior of a bridge was affected when AAR occurred in the connected pavement. The newly installed joints shrank in the longitudinal direction of the bridge after cutting. The width of the joints decreased over the six months after cutting. A large portion of the joint width (8.5cm) was found to have closed nine months after cutting. It had ultimately shrunk by about 92 percent when the final measurement was taken. CONCLUSIONS : The expansion of the pavement due to AAR was quantitatively described by visual inspection and the long-term monitoring of the newly cut joints. However, the width of the new joints decreased over the six to nine months after cutting. Additional research should be conducted to determine a means of controlling the expansion due to AAR in the pavement.

PURPOSES : This study set out to investigate the fundamental properties of alkali-activated concrete (AAC) using modified slag as the pavement maintenance material. METHODS: The material properties of modified slag based alkali-activated concrete (MSAAC) were analyzed and evaluated against those of alkali-activated slag concrete (AASC). Several mix formulations were considered, including one MSACC and four AASCs. The main variables considered in the study were slump, air content, compressive strength, rapid chloride permeability test, scaling resistance, freeze-thaw test, XRD, SEM, and EDS. RESULTS: MSAAC exhibits a compressive strength in excess of 21 MPa six hours after curing. Also, the charge passed of the MSACC was found to be less than 2000 coulombs after seven days and about 1000 coulombs after 28 days. The weight loss determined from a scaling test did not exceed 1 kg/cm2 in the case of the MSACC, but that of the AASCs had already exceeded 1kg/cm2 at the 10th cycle. Based on the results of the freeze-thaw test, the relative dynamic modulus of every mix was found to be in excess of 90%. An energy dispersive spectroscopy(EDS) analysis found that the weight rate percentage of the calcium and aluminum in the MSAAC mix is twice that of the AASC mixes. CONCLUSIONS : It was found that the MSAAC mix exhibits significantly better performance than AASC mixes, based on various fundamental properties.

Activated carbon fibers(ACFs) were prepared in this research from a polyacrylonitrile(PAN) precursor with the KOH(1~4 M) pretreatment and following activation at 800oC in a lab-scale. The sample ACFs were characterized according to their textural properties, and evaluated for CO2 adsorption capacity. The surface area and pore volume of ACFs increased according to the pretreatment with KOH; for example, 4M-KOH aqueous solution resulted in 1552.5 m2/g specific surface area and 0.605 cc/g pore volume. It also showed high CO2 adsorption amount(3.11 mmol/g) which showed a proportional increase with reaction pressure.

Physicochemical and sensory properties of puffed rice snack containing various levels (0%, 50%, 100%) of alkali-cooked brown rice were examined. To prepare alkali-cooked rice, brown rice was cooked in boiling 2% Ca(OH)2solution for 5 min, steeped for 3 h, and dried at 50oC for 18 h. Alkali-cooked rice showed a higher degree ofexpansion than that of untreated rice after puffing. Although moisture content, enzyme susceptible starch (ESS), anddensity of puffed rice snack decreased with increasing amounts of the alkali-cooked rice replacement, calcium con-tent increased because of the absorption of calcium during alkaline processing. The puffed rice snack had a darkercolor as the level of replacement with alkali-cooked rice increased. A sensory test revealed that puffed rice snackreplaced with 50% of alkali-cooked rice had no significant differences in color and sensory attributes from those ofthe control. These results indicate that fortification of calcium could be achieved by partial replacement of alkali-cooked rice without any detrimental effects on the quality of puffed rice snack.

알칼리 가수분해에 따른 보리 β-glucan의 이화학적 특성변화를 살펴보기 위하여 새쌀보리, 새찰쌀보리 및 흰찰쌀보리에 0.2~1.0 N NaOH를 처리하였으며, 총 및 수용성 β-glucan의 함량 및 순도, 수용성 β-glcuan의 분자량, 점도 및 재용해율을 살펴보았다. 3품종 보리의 총 β-glucan 함량은 7.77~8.40% 범위이었으며, 알칼리 가수분해 농도가 증가함에따라 6.89~7.54% 범위로 감소하였다. 수용성 β-glucan의 함량은 무처리의 4.16~4.80% 범위에서 알칼리 가수분해 농도가 증가함에 따라 4.30~4.82% 범위로 유의적인 차이가 없었다. 수용성 β-glucan의 순도는 3품종 모두 30.91~35.79% 범위이었으나, 알칼리 가수분해에 의해 74.02~81.41%까지 증가하였다. 분자량은 메성보리보다 찰성보리가 더 컸으며, 알칼리 가수분해 농도가 증가함에 따라서 크게 감소하였다. β-Glucan 수용액의 점도는 알칼리 가수분해 농도가 증가함에 따라 감소하였으며, 메성보리보다 찰성보리가 높았고, 흰찰쌀보리보다 새찰쌀보리가 높았다. 재용해율은 무처리의 50~55% 범위에서 알칼리 가수분해 농도가 증가함에 따라 증가하여 1.0 N NaOH 처리구에서 80.00~87.66% 범위로 증가하였다.

In this study, CO₂ adsorbent was produced for minimizing energy loss due to ventilation within the building. For improved selectivity about low concentration of CO₂ in multiple-use facilities, the ball type adsorbent was modified from a commercial zeolite, alumina, alkali metals and activated carbon with mixing LiOH, binder, and H₂O. We measured specific surface area, pore characteristic, and crystal structure of the modified adsorbent. Effects of alkalization on the absorptive properties of the adsorbents were investigated. Continuous column tests (2,000 ppm) and batch chamber tests (4m3, 5,000ppm) showed that the modified adsorbent indicated about the selectivity of CO₂ more than 9.7% (0.613 mmol/g) compared with ordinary adsorbents and CO₂ removal efficiency of 88.8% within l hour, respectively. It was estimated that the modified adsorbent was applicable to indoor environments.

PURPOSES : This study is to evaluate the feasibility of using the alkali activated cement concrete for application of partial-depth repair in pavement. METHODS : This study analyzes the compressive strength of alkali activated cement mortar based on the changes in the amount/type/composition of binder(portland cement, fly ash, slag) and activator(NaOH, Na2SiO3, Na2CO3, Na2SO4). The mixture design is divided in case I of adding one kind-activator and case II of adding two kind-activators. RESULTS : The results of case I show that Na2SO4 based mixture has superior the long-term strength when compared to other mixtures, and that Na2CO3 based mixture has superior the early strength when compared to other mixtures. But the mixtures of case I is difficult to apply in the material for early-opening-to-traffic, because the strength of all mixtures isn't meet the criterion of traffic-opening. The results of case II show that NaOH-Na2SiO3 based mixtures has superior the early/long-term strength when compared to NaOH-Na2SiO3 based mixtures. In particular, the NaOH-Na2SiO3 based some mixtures turned out to pass the reference strength(1-day) of 21MPa as required for traffic-opening. CONCLUSIONS : With these results, it could be concluded that NaOH-Na2SiO3 based mixtures can be used as the material of pavement repair.

PURPOSES : This study is to evaluate the feasibility of setting the standard of cement alkali content by using ASTM C 1260(accelerated mortar bar test) METHODS : This study analyzes the ASR(alkali silica reaction) expansion of cement mortar bar based on the changes in the aggregate type(fine, coarse), cement type(ordinary, low alkali), and replacement contents of fly ash. ASR tests were conducted according to ASTM C 1260. RESULTS : In this test results, There is no big difference in the ASR expansion between ordinary cement and low alkali cement. From this test results, it was found that the variation of cement alkali content did not have a effect on ASR expansion because mortar bar was placed in a container with sufficient alkali aqueous solution at high temperature during the test process of ASTM C 1260. CONCLUSIONS : It is evidently clear that the alkali content of cement have a effect on ASR. But ASTM C 1260 is difficult to assess this effect.

PURPOSES: The purpose of this study is to compare the alkali-silica reactivity for mortar bar and concrete prism specimens using crushed aggregates of 5 types in Korea. And the alkali-silica reactivity for those aggregates are measured by chemical test method. METHODS: The alkali-silica reactivity for those aggregates was measured by chemical test method of KS F 2545, mortar-bar test of KS F 2546, accelerated mortar-bar test method of ASTM C 1260 and concrete prism test method of ASTM C 1293, relatively. RESULTS: The alkali-silica reactivity for those aggregates was verified by chemical test of KS F 2546 and accelerated mortar-bar test of ASTM C 1260. However, it was not by mortar-bar test of KS F 2546 and concrete prism test of ASTM C 1293. CONCLUSIONS: The above results showed that relationship among the four test methods were very low. The results from 3 types of test methods using cement-aggregate combinations appeared to be different. Because the environmental conditions of test methods for measuring the alkali-silica reactivity such as equivalent alkali content(external source), humidity, temperature, and times were different though the aggregates were same. Moreover, alkali-silica reactivity showed the biggest impact when alkalis were supplied form outside and exposed to environmental conditions. The accelerated mortar-bar test method seems to be most appropriate test method for concrete structures exposed to alkali environment.

국내에서는 콘크리트 포장용 굵은 골재를 대상으로 화학적인 시험방법과 모르타르 봉 시험방법을 이용한 결과 알칼리-실리카 반응 유해 가능성이 낮은 것으로 알려져 왔으나, 최근에 알칼리 - 실리카 반응에 의한 파손이 발생되었고, ASTM C 1260을 이용한 결과 일부 골재에서 유해한 팽창이 발생된다고 보고되었다. 따라서 본 논문에서는 모르타르 봉 시험방법인 KS F 2546과 ASTM C 1260을 이용하여 길이 팽창 유도기간의 환경조건이 알칼리 - 실리카 팽창 반응 특성에 미치는 영향을 평가하고자 하였다. KS F 2546의 경우 대상 골재 모두 반응성 없음으로 판정되었으나 ASTM C 1260에서는 일부 골재에서 잠재반응성 이상으로 판정되었다. 이는 외부로부터의 알칼리 이온의 공급, 온도 및 습도 차이에 의하여 발생한 것으로 판단된다. 또한 ASTM C 1260에서 NaOH의 농도변화 실험을 통하여 NaOH의 농도가 증가할수록 길이팽창이 현저하게 증가한다는 것을 확인하였으며, 온도 및 습도가 증가함에 따라 길이팽창이 증가한다는 것을 확인하였다.

The continuous transesterification of mixed fat was done on the plug flow reactor packed with the static mixers. The transesterification using 0.5 wt% KOH, 0.8 wt% TMAH and mixed catalyst[40 v/v% KOH(0.5 wt%)+60 v/v% TMAH(0.8 wt%)] was conducted with the changes of molar ratios, weight percentage of beef, flow rates and number of static mixer's elements at 65℃. The overall conversion of mixed fat at 1:8 molar ratio, 50 wt% of beef and 24 of static mixer's elements increased until 0.7mL/min of flow rate. The overall conversion of mixed fat showed 96% at those conditions. So, the optimum operating conditions on tublar reactor were 1:8 molar ratio, 50 wt% of beef, 0.7 mL/min of flow rate and 24 of static mixer' s elements.

In this study, a new, relatively simple fabrication method for forming a mesoporous Al(OH)3 film onAl substrates was demonstrated. This method, i.e., alkali surface modification, was simply comprised of dippingthe substrate in a 5×10-3M NaOH solution at 80oC for one minute and then immersing it in boiling waterfor 30 minutes. After alkali surface modification, a mesoporous Al(OH)3 film was formed on the Al substrate,and its chemical state and crystal structure were confirmed by XPS and TEM. According to the results of theXPS analysis, the flake-like morphology after the alkali surface modification was mainly composed of Al(OH)3,with a small amount of Al2O3. The mesoporous Al(OH)3 layer was composed of three regions: an amorphous-rich region, a region of mixed amorphous and crystal domains, and a crystalline-rich region near the Al(OH)3layer surface. It was confirmed that the stabilization process in the alkali surface modification stronglyinfluenced the crystallization of the mesoporous Al(OH)3 layer.

The esterification of palmitic acid in Jatropha Oil using 8wt% p-TSA catalyst was done at the 1:8 molar ratio of oil to methanol and 65℃. The conversion of palmitic acid appeared to be 95.3% in 60min. After that, the continuous transesterification of the oil using 0.5wt% KOH, 0.8wt% TMAH mixed catalyst[40vol% KOH(0.5wt%) + 60vol% TMAH(0.8wt%)] and 1.1wt% TMAH was conducted with the flow rates and the molar ratios at 65℃. The overall conversion of Jatropha Oil increased with the decrease of flow rate and showed 95.6% with 9ml/min of flow rate at the 1:8 molar ratio of oil to methanol and 65℃. But it showed 87% with 15ml/min of flow rate at the same conditions. The recovery of methanol(%) appeared to be 86% at the 1:8 molar ratio of oil to methanol, mixed catalyst and 65℃.

Ti scaffolds with a three-dimensional porous structure were successfully fabricated using powder metallurgy and modified rapid prototyping (RP) process. The fabricated Ti scaffolds showed a highly porous structure with interconnected pores. The porosity and pore size of the scaffolds were in the range of 66~72% and 300~400 μm, respectively. The sintering of the fabricated scaffolds under the vacuum caused the Ti particles to bond to each other. The strength of the scaffolds depended on the layering patterns. The compressive strength of the scaffolds ranged from 15 MPa to 52 MPa according to the scaffolds' architecture. The alkali treatment of the fabricated scaffolds in an aqueous NaOH solution was shown to be effective in improving the bioactivity. The surface of the alkali-treated Ti scaffolds had a nano-sized fibre-like structure. The modified surface showed a good apatite forming ability. The apatite was formed on the surface of the alkali treated Ti scaffolds within 1 day. The thickness of the apatite increased when the soaking time in a simulated body fluid (SBF) solution increased. It is expected that the surface modification of Ti scaffolds by alkali treatment could be effective in forming apatites in vivo and can subsequently enhance bone formation.