• Title/Summary/Keyword: calcium salts

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Advanced Membrane Systems for Seawater Desalination. Kinetics of Salts Crystallization from RO Brines Promoted by Polymeric Membranes

  • Curcio, Efrem;Obaidani, Sulaiman Al;Macedonio, Francesca;Profio, Gianluca Di;Gualtieri, Silvia;Drioli, Enrico
    • Membrane Journal
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    • v.17 no.2
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    • pp.93-98
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    • 2007
  • The reliability of innovative membrane contactors technology (i.e. Gas/Liquid Membrane Contactors, Membrane Distillation/Crystallization) is today increasing for seawater desalination processes, where traditional pressure-driven membrane separation units are routinely operated. Furthermore, conventional membrane operations can be integrated with membrane contactors in order to promote possible improvements in process efficiency, operational stability, environmental impact, water quality and cost. Seawater is the most abundant aqueous solution on the earth: the amount of dissolved salts covers about 3% of its composition, and six elements (Na, Mg, Ca, K, Cl, S) account for more than 90% of ionic species. Recent investigations on Membrane Distillation-Crystallization have shown the possibility to achieve significant overall water recovery factors, to limit the brine disposal problem, and to recover valuable salts (i.e. calcium sulphate, sodium chloride, magnesium sulphate) by combining this technology with conventional RO trains. In this work, the kinetics of $CaSO_4{\cdot}2H_2O,\;NaCl\;and\;MgSO_4{\cdot}7H_2O$ crystallization is experimentally investigated in order to improve the design of the membrane-based crystallization unit.

A Case Study on Chloride Corrosion for the End Zone of Concrete Deck Subjected to De-icing Salts Added Calcium Chloride (염화칼슘이 함유된 제설제로 인한 콘크리트 바닥판 단부의 염해에 관한 사례 연구)

  • Chung, Jee-Seung;Kim, Bo-Heon;Kim, Il-Sun
    • Journal of the Korean Society of Safety
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    • v.29 no.6
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    • pp.87-93
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    • 2014
  • In this study, the reinforced concrete rahmen bridge damaged by the chloride attack was investigated. According to the investigation, the degraded concretes on cantilever kerb and end part were intensively observed. Thus, the chloride content test and half-cell method were performed to evaluate the degraded parts. As a result, the contents of chloride on degraded parts were C and D grade. On the other hand, the half-cell potential values of rebar in degraded concrete were measured with the minor corrosion. This rebar corrosion is expected to progressing. Chloride content D grade is due to expansion pressure by corrosion of rebar and freeze-thaw by permeate water, could see progresses rapidly degradation. In order to prevent chloride attack to concrete deck caused by deicing salts, corresponding to the chloride critical concentration must maintain grade b or at least grade c. Chloride condition evaluation standard apply to evaluation of marine structure chloride attack with chloride attack by deicing salts.

Electrokinetic Restoration of Saline Agricultural Land (염류집적 농경지의 전기동력학적 정화)

  • Jo, Sung-Ung;Kim, Do-Hyung;Yang, Jung-Seok;Chung, Keun-Yook;Baek, Ki-Tae
    • Journal of Soil and Groundwater Environment
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    • v.17 no.4
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    • pp.19-26
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    • 2012
  • The influence of operation time on electrokinetic restoration was investigated to remove salts from sulfate-accumulated greenhouse soil. Operation time is directly related to the process cost, therefore, we determined the relationship between operation time and removal of salts. Nitrate and sodium were removed almost completely within 2 weeks, chloride and calcium was removed in proportion to the operation time. Sulfate was accumulated at the center of anode and cathode. The soil electrical conductivity (EC), an indicator for soil salinity, showed similar shape with the residual sulfate after electrokinetic treatment. The soil EC was not changed after 2 weeks, however, the energy consumption increased with operation time. Based on the experimental results, most salts except sulfate were removed within 2 weeks, but sulfate was not removed during same time period. For the further removal of sulfate, longer operation time is in need.

Transport and Distribution of Calcium Salts in Tofu Manufacturing Process -Part II. Mass Balances of Calcium Salt during Tofu Manufacturing Processes by Conductometric Method- (두부 제조(製造) 공정중(工程中) Calcium염(鹽)의 행동(行動)과 분포(分布) -제2보(第二報). 전기 전도도법을 이용한 두부제조 공정중 Ca염의 수지-)

  • Lee, Chon-Ki;Yim, Sang-Bin;Chun, Jae-Kun
    • Applied Biological Chemistry
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    • v.28 no.2
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    • pp.56-61
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    • 1985
  • The mass balances of calcium salts during the manufacturing processes of Tofu were established by conductometric method and chemical analysis method. During the manufacturing processes of soy milk and Tofu, 66% of solid and 63% of calcium was transfered from soy-bean to the soy milk, and 47.8% of total solid from soybean was transfered to the Tofu, respectively. When the $CaCl_2$ was used as coagulant, calcium contents in Tofu $(Y_{Tofu},\;mg{\cdot}Ca/g{\cdot}Tofu,\;wet\;basis)$ and drained solution $(Y_{drained\;soln},\;mg{\cdot}Ca/ml{\cdot}drained\;soln.)$ were linearly increased with the amounts of $CaCl_2(C,g{\cdot}CaCl_2/ml{\cdot}soy\;milk)$ added in soy milk, and correlative equations between them were obtained as $Y_{Tofu}=0.3369\;C+1.2689$ for Tofu$(moisture\;content:\;81.5{\pm}0.5%)$ with r=0.9898, and $Y_{drained\;soln}= 0.2899C+0.0399$ for drained solution with r= 0.9991. It was proved that conductometric method was reasonably applicable to the measurement of calcium contents of the products from every processes of Tofu manufacture except soy-bean. However the conductometric method was not recomendable in the case of $CaSO_4$ as coagulant due to its low solubility ana uneven distribution in soy milk and Tofu tissue.

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The Protective Role of Calcium in the Lethal Actions of Certain Metal Ions on the Growth of Lemna and Arabidopsis Plants (각종 금속염의 Lemna 및 Arabidopsis에 대한 치사작용과 석탄의 그 보호작용에 관하여)

  • Chung, Jun;Kwack, Beyoung-Hwa
    • Journal of Plant Biology
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    • v.12 no.3
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    • pp.1-7
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    • 1969
  • The lethal actions in Arabidopsis thaliana and Lemna polyrhiza brought about by certain inorganic form of Mn, Ba, Hg, Cu salts, and organic form of Na salts, were studied with aseptic artificial media. These metal ions at certain concentrations caused lethality of either Arabidopsis or Lemna when the media were without Ca ion. On the contrary, addition of Ca to the media protected the organisms from such lethality. It was postulated for the present from the proceeding evidence that Ca adsorbed and distributed along the sites between the plasma and cell membrane acts for suppressing permeation of toxic level of metal ions causing the lethality of these plants.

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고정화된 Pantoea aggromerans에 의한 토양에서의 가용성 인산의 생성

  • Im, Won-Bong;Jeong, Gwi-Taek;Park, No-Dong;Yun, Jeong-Han;Kim, Si-Uk;Park, Don-Hui
    • 한국생물공학회:학술대회논문집
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    • 2002.04a
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    • pp.403-406
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    • 2002
  • This experimental shows the possibility of using as biofertilizer, which convert insoluble inorganic phosphate salts to plant-usable phosphate type by immobilized microorganism with calcium alginate. In the case of culture of P. agglomerans on constant medium pH, phosphate was produced 357 mg/L after 18hrs. And in the case of culture of immobilzed P. agglomerans bead, phosphate was produced maximum 295.6 mg/L after 120 hrs. Also as using rock phosphate as insoluble phosphate salts, phosphate was respectably produced 190.3 and 195.2 mg/L after 36 hrs at free cells and immobilized cells. In our experiments, the using soils contained 23.16 g-P/kg-soil total phosphate and 3.76 g-P/kg-soil soluble phosphate. The result of 1g immobilized bead seeding, soluble phosphate was produced maximum 6.14 g-P/kg-soil phosphate and this value was increased continuously.

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Early Hydration Properties of Calcium Aluminosulfate (3CaO · 3Al2O3 · CaSO4) Prepared by Chemical Synthesis

  • Kim, Hoon-Sang;Kim, Hyung-Chul;Song, Jong-Taek
    • Journal of the Korean Ceramic Society
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    • v.39 no.7
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    • pp.617-621
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    • 2002
  • Calcium aluminosulfate (3CaO.3Al$_2$O$_3$.CaSO$_4$or $C_4$A$_3$S) was prepared by chemical synthesis from the nitrate salts and aluminum sulfate. $C_4$A$_3$S was the main phase after calcination at 110$0^{\circ}C$. The specific surface areas after calcination at 110$0^{\circ}C$ and 130$0^{\circ}C$ were about 2.5 and 1.0 $m^2$/g, respectively. Hydration was investigated by XRD, DSC, SEM, EDS, conduction calorimetry and analysis of the liquid phase. Calorimetry showed that the induction period was longer than that of a sample prepared by conventional solid state sintering and this was attributed to the formation of amorphous coatings in abundance of $Al_2$O$_3$ and SO$_3$. Crystalline hydration products, principally calcium monosulfoaluminate hydrate and Al(OH)$_3$, appeared subsequently.

THE EFFECT OF FILLERS ON THE DEINKING OF PHOTOCOPIED PAPER

  • Chen, Qing-min;Chang, Hou-min;Ethan K. Andrews;Heinz G. Olf
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 1999.11b
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    • pp.159-163
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    • 1999
  • Model experiments were conducted to investigate the effect of different fillers on the removal of toner ink. Combinations of different papers (commercial photocopy paper and filler-free paper), fillers (calcium carbonate, kaolin clay, and talc), and chemicals(1-octadecanol, stearic acid, oleic acid, and TOFA) and stearic acid were found to be effective in detachment and agglomeration of toner ink. Furthermore, pH had little effect on toner detachment and agglomeration, indicating both protonated fatty acids and their anions are equally effective. In the presence of either kaolin clay or talc, all these agglomerating agents are equally effective, although a slightly higher dosage(1% for clay and 2% for talc as compared with control) is required, presumably due to the adsorption of chemical by the filler. Calcium carbonate filler, on the other hand, has a significant and adverse effect on the fatty acids used but has little effect on 1-octadecanol with the exception of possible adsorption. While stearic acid is not effective, a much higher level of oleic acid or TOFA is needed when calcium carbonate fillers are present as compared to the filler-free case. Fatty acids react with calcium carbonate to form calcium salts. The availability of fatty acid anion for toner detachment and agglomeration is determined by the solubility of calcium salt of a given fatty acid. Calcium oleate is 10 times more soluble in water than calcium stearate.

Combination Pretreatment of Calcium and Vitamin C to Enhance the Firmness of Kimchi Sterilized with High-dose Gamma Irradiation

  • Song, Beom-Seok;Kim, Mi-Jung;Park, Jin-Gyu;Kim, Jae-Hun;Kim, Duk-Jin;Han, Sang-Bae;Shin, Jung-Kue;Byun, Myung-Woo;Lee, Ju-Woon
    • Food Science and Biotechnology
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    • v.17 no.4
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    • pp.751-754
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    • 2008
  • Texture analysis, sensory evaluation, and scanning electronic microscopic (SEM) observation were conducted to evaluate the effects of different calcium salts (calcium lactate, calcium acetate, and calcium chloride) and vitamin C on the textural properties of kimchi, gamma-irradiated at 25 kGy. Increase of the hardness and sensory score were observed in the kimchi pretreated with calcium salt or vitamin C as compared with the untreated and irradiated kimchi. And the hardness and sensory quality of the co-pretreated sample with 0.01% of calcium lactate and 0.3% of vitamin C were the highest after 30 days at $35^{\circ}C$, which indicates that the co-pretreatment is effective in preventing a decrease of the texture and sensory qualities of kimchi by gamma irradiation. Also, this result was supported by the SEM observation.

Chemical Forms of Ca, Mg Compounds Occuring in Perilla Leaves and Their Changes after Harvest (깻잎에 있어 Ca, Mg의 존재형태와 수확후의 변화)

  • 최영희
    • Journal of the East Asian Society of Dietary Life
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    • v.11 no.4
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    • pp.274-280
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    • 2001
  • The chemical forms of calcium compounds in perilla leaves and their changes after harvest were investigated. The four types of calcium compounds extracted were as follows: water soluble calcium(F-I: mainly water soluble organic acid salts and calcium ion), IN-sodium chloride soluble calcium(F-II: calcium-pectate and calcium-carbonate), 2%-acetic acid soluble calcium(F-III: calcium-phosphate), and 5%-hydrochloric acid soluble calcium(F-IV: calcium-oxalate). The calcium content of perilla leaves was not found to vary with their age. Relatively high levels of F-l (28.4~39.5) and F-II (34.4~47.4) were found in young and mature leaves while the F-IV constituted 15.6~21.6% of the total calcium. The F-IV calcium contents of perilla. spinach and jaso were 16.8, 42.4 and 22.3%, respectively. In contrast to calcium. magnesium existed as water soluble magnesium at the highest content of 90.6% in spinach while 62.9% and 16.8% of the total magnesium existed as water soluble magnesium in perilla and jaso, repectively. The change in vitamin C and F-IV calcium content were examined for 7 days after harvest. Vitamin C content decreased slowly at the beginning but rapidly from the 4th day after harvest. On the other hand, the F-IV calcium content increased slowly at the beginning and rapidly from the 4th day of observation. This result suggests that the increase in F-IV calcium is related to the decrease in vitamin C content. This phenomena was more distinctly observed at 2$0^{\circ}C$ than 5$^{\circ}C$.

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