• Applied Chemistry for Engineering
• /
• v.22 no.5
• /
• pp.526-531
• /
• 2011

The present study attempted to impregnate alkali metals to amino acid in order to improve $CO_2$ absorption capacity. A used amino acid was glycine, of which pH increased up to about 11 with the addition of alkalies. $CO_2$ absorption capacity of amino acid salts was evaluated in a batch and a continuous process. The absorption capacity appeared in turns as; Sodium Glycinate ${\geq}$ Lithium Glycinate > Potassium Glycinate. Amino acid salts showed lower absolute capacity of $CO_2$ absorption than primary amine (Monoethanolamine) at $20^{\circ}C$. In a continuous absorption with 10% $CO_2$ flow, the increasing the reaction temperature, the increasing rate of absorption for amino and was higher that of than amino absorbent.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.7
• /
• pp.801-809
• /
• 2007

Fly ash and blast furnace slag are an industrial by-product that can be alkali-activated to yield adhesive and cementitious materials, whose production is less energy-intensive and emits less $CO_2$ than ordinary Portland cement manufacture. A laboratory investigation was carried out to evaluate the effect of alkali-activating conditions on compressive strength of fly ash/slag cement and the acid corrosion resistance of this cement. Two alkali activator solution, NaOH and waterglass + NaOH solutions, were used. Waterglass concentration was the factor that gave the highest compressive strength in all tests. The next significant factor was the NaOH concentration, followed by curing temperature. Acid corrosion resistance of FC(fly ash cement) and FSC(fly ash/slag cement), such as sulfuric$(H_2SO_4)$ and hydrochloric acid(HCl), was for better than Portland cement(PC).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.5 no.2
• /
• pp.103-108
• /
• 2007

The absorption spectra of Pu in stock solution were measured using a UV-Vis-NIR spectrophotometer after dissolving $PuO_2\;with\;HNO_3$, HF and $HClO_4$. The spectroscopic characteristics of Pu (III, IV, VI) in acidic, neutral and alkali media were investigated. Also, the intensities and position of major peaks for Pu(VI) were observed with increasing acidic and alkali concentration. The variation of oxidation states of Pu(VI) with an adding reducing reactant was investigated in HCl and NaOH medium.

• Applied Chemistry for Engineering
• /
• v.7 no.4
• /
• pp.698-706
• /
• 1996

Dehydrogenation of methanol to produce formaldehyde was carried out over various silica-alumina catalysts doped with alkali metals in a continuous flow system. The reaction was rather dependent on Lewis acid than Br${\ddot{o}}$nsted acid suggesting that dehydrogenation of methanol was an electronic reaction. The Br${\ddot{o}}$nsted acid sites on silica-alumina were neutralized by doping with alkali metals, and the neutralization effect of Br${\ddot{o}}$nsted acid was dependent on the electron-donating capacity of the dopant metals. Activation energy for dehydrogenation of methanol decreased when Br${\ddot{o}}$nsted acid was neutralized by doping with K.

• Journal of Korea Soil Environment Society
• /
• v.2 no.2
• /
• pp.73-79
• /
• 1997

Removal of the Arsenic components from the closed mine tailings has been attempted by the alkali-leaching method. Two tailings collected from the Daduck and Yuchon mine which were already closed many years ago were leached with caustic soda solutions. The Arsenic components in the leach liquor resulted from the alkali treatment of tailings could be removed fairly well in the form of insoluble calcium-Arsenic compound by the precipitation with calcium chloride. As a result, the extraction of about 60~90% Arsenic from the tailings could be obtained depending on the leaching conditions and the influence of temperature and the slurry density on the extraction of Arsenic was also found to be very small at the NaOH concentration more than 0.5N. In addition, it seemed that a caustic soda solution over 0.5N NaOH could be used repeatedly for the leaching of tailings since the consumption of NaOH was not so great in a leaching of them. As far as the precipitation of Arsenic components was concerned, more than 99% of Arsenic could be precipitated within 10 minutes by the addition of 2wt% CaC12 in to the leach liquor.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.3
• /
• pp.271-275
• /
• 1999

The chemical and gelling properties of porphyran from Porphra yezoensis collected from Buan and Wido in Korea at different months of the year were studied. Crude porphyran was prepared by hot-water extraction and further purified by cetylpyridinium chloride precipitation, Crude porphyran and porphyran were modified by alkali treatment to eliminate sulfate. The yields of alkali-modified crude porphyran (AMCP) and porphyran(AMP) were between $4.9\~10.9\%$ and $4.0\~6.7\%$ of the dried algae weight and were maximum in February for Buan and January for Wido, respectively. Gel strength of AMCP were highest in February ($790g/cm^2$) for Buan and January ($740 g/cm^2$) for Wido. Alkali modification increased 3,6-anhydro galactose content and the molar ratio of galactose and 3,6-anhydrogalactose of AMCP and AMP showed 1 : 0,8$\~$1.1. GLC and FT-IR measurement of AMP showed that most of sulfate residues were combined to C-6 of galactose, Thus, results of this study suggest that crude porphyran extracted from Porphra yezoensis produces an agar of a reasonably good quality after alkali treatment.

• Proceedings of the Korean Printing Society Conference
• /
• 2001.06a
• /
• pp.45-45
• /
• 2001

자료의 보존에 있어서 종이의 열화로 인해 자료의 분석, 열화메커니즘의 해석, 종이의 보존이란 측면 하에서의 관심이 서서히 집중되고 있는 실정이며, 그 중요성도 크게 대두되고 있는 실정이다. 산성지를 중성화하는 화학적시스템, 즉, 탈산성화처리는 알카리계금속(Ca, Mg, Zn, Na)과 유기용매, 수용성용매를 이용하여 이들 약품을 종이내에 침투시켜 중성화(pH 6-8) 함으로써 종이의 주성분인 cellulose를 보다 안정화시키는 방법으로 산을 중화하여 보존성을 향상시킬 수 있는 것이다. 즉, 탈산처리란 화학적으로 종이속에 생기는 산 또는 산을 발생하는 물질을 알칼리물질로 중화하는 것이다. 또한 중화후 알칼리 물질이 종이에 잔류하면 장래에 내부적으로 발생하는 산이나 외부(대기중의 오염물질 등) 로부터 침입하는 산도 중화하여 보존성을 향상시킬 수가 있다. 따라서, 본 연구는 산성초지법에 의해 제조된 용지들의 열화특성과 알카리 토금속을 처리한 후에 알카리도를 상승시킨 용지의 열화특성을 물리·화학적 변화를 통하여 종이의 보존성을 비교 검토·규명함으로써 문(도)서의 보존체계를 마련하고자 하며, 보존과 관련된 기초자료를 얻고자 실시하였다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.323-324
• /
• 2010

The purpose of this study was to investigate alkali-silica reaction of accelerating agents in shotcrete. The test was performed with accelerating agents (aluminate, alkali-free, cement based mineral admixture) in the Type I cement. As a test result, using the nonreactive aggregates, detrimental expansion due to alkali-silica reaction doesn't occurred regardless of equivalent alkali contents of accelerating agent.

• Food Science and Preservation
• /
• v.11 no.4
• /
• pp.530-537
• /
• 2004

This study was conducted to determine the inactivation effect of electrolyzed water and organic acids either alone or in combination on L. monocytogenes or natural microflora on lettuce. Acidic electrolyzed water completely inactivated L. monocytogenes in broth system within 60 sec, but alkalin electrolyzed water caused approximate 1.7 log CFU/g reduction. However, acidic electrolyzed water reduced only 2.5 log CFU/g of L. monocytogenes on lettuce, and similar antimicrobial effect was observed with alkalin electrolyzed water. In the meantime, acidic and alkaline electrolyzed water caused approximately 2 log CFU/g reduction compared to control, whereas both electrolyzed water combined with $1\%$ organic acids ranged from 2.6 to 3.7 log CFU/g reduction. Among the organic acids, both electrolyzed water combined with $1\%$ citric acid showed the strongest synergistic antimicrobial effect to reduce L. monocytogenes on lettuce as well as total counts, yeast and molds. When antimicrobials, alone or in combination were treated into L. monocytogenes inoculated lettuce at $5^{\circ}C\;and\;15^{\circ}C$ for designed periods, the combined alkalin electrolyzed water with $1\%$ citric acid showed the greatest potential to inhibit growth of the bacteria. According to Scanning Electron Microscopy(SEM), the treatment of electrolyzed alkali water in combination with $1\%$ citric acid highly reduced the growth of the L. monocytogenes compared to single treatment and resulted in causing the destruction of cell membrane.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.1
• /
• pp.61-68
• /
• 2008

A new cementitious material has been developed, called alkali-activated fly ash cement(AAFC), which is used to produce AAFC-concrete for construction. The effect of acid attack, sodium chloride solution, carbonation, freeze-thaw cycling, and SEM, XRD analysis of the AAFC-concrete prepared using alkali-activated fly ash cement and OPC-concrete were experimentally investigated. It was found that the acid resistance of AAFC-concrete(35 MPa) prepared from alkali-activated fly ash at 85$^{\circ}C$ for 24 hrs is far better than OPC-concrete(35 MPa). Also, the AAFC-concrete(35 MPa) had a similar resistance of OPC-concrete(35 MPa) to attack, such as sodium chloride solution, carbonation and freeze-thaw cycling.