• Title, Summary, Keyword: Citrate process

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Purity Improvement of Calcium Lactate and Calcium Citrate Prepared with Shell of Anadarac tegillarca granosa (꼬막 패각으로 제조한 젖산칼슘과 구연산칼슘의 순도 향상에 대한 연구)

  • Kang mee-Sook;Soh Gowan-Soon;Shin Dong-Hwa
    • Journal of Food Hygiene and Safety
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    • v.20 no.3
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    • pp.128-133
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    • 2005
  • Ash of Anadarac tegillarca granosa shell was used for preparation of calcium lactate and calcium citrate, and improvement of their purity was carried out by using ammonium chloride process (ACP) and ammonium nitrate process (ACP). Purity of calcium lactate and calcium citrate made by the reaction of ash of Anadarac tegillarca granosa shell with lactic acid solution and with citric acid solution was 94.35-96.72 and $87.58-93.06\%$, respectively. However, purity of calcium lactate and calcium citrate prepared with purified calcium carbonate pre-purified from the ash of Anadarac fegiliarca granosa shell using ACP and ANP method was 99.53-100.34 and $99.32-99.88\%$, respectively. The purity of these calcium products were higher than those of calcium lactate and calcium citrate made with ash of Anadarac tegillarca granosa shell. Whiteness of calcium lactate and calcium citrate prepared with purified calcium carbonate pre-purified using ACP and ANP method was 94.8-98.5 and 99.4-101.5, respectively. Whiteness of these calcium products was higher than that of calcium lactate (91.8) and calcium citrate (92.9) made with the ash of Anadarac tegillarca granosa shell. Therefore, we estimated that calcium lactate and calcium citrate prepared with purified calcium carbonate using ACP and ANP method could be used potentially as a food additive for calcium supplement.

Preparation of High Tc YBa2Cu3O7-x Powders by Citrate and Nitrate Processes (Citrate, Nitrate Process에 의한 YBa2Cu3O7-x초전도 분말합성)

  • 박수련;김윤호
    • Journal of the Korean Ceramic Society
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    • v.26 no.2
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    • pp.221-227
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    • 1989
  • To investigate the development and densification YBa2Cu3O7-x(1-2-3) superconducting phase, the 1-2-3 phase powders have been prepared by citrate and nitrate processes with changing calcination temperature. Nearly pure 1-2-3 phase peaks have been obtained by calcining the precursor in air at 90$0^{\circ}C$ for 2.5h in citrate process but at 95$0^{\circ}C$ for 2.5h in nitrate process. The sintering density of citrate derived sample calcined at 80$0^{\circ}C$ has been about 4% higher than that calcined at 90$0^{\circ}C$, although the compacting density has been lower at 80$0^{\circ}C$ calcination. This can be explained that the 1-2-3 phase particles formed at 80$0^{\circ}C$ have reactive sub-micron size which has good sinterbililty.

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The Extraction Characteristics of Metal-contaminated Soil by Soil Washing (토양세척기법을 이용한 중금속 오염토양 처리에서 중금속 추출특성)

  • Hwang, Seon-Suk;Lee, Noh-Sup;NamKoong, Wan
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.10
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    • pp.1072-1080
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    • 2005
  • The extraction characteristics of heavy metals(HM) from a contaminated soil at existing lead smelters were investigated with ethylene diamine tetraacetic acid(EDTA), citrate and HCl as washing solutions. EDTA was more effective for Pb than for other heavy metals. As the mol ratio of EDTA/HM increased, the removal efficiency of heavy metals became higher. When the mol ratio of EDTA/HM approached to 6.5, it removed Pb most effectively. Citrate was effective especially in extracting Zn. The removal efficiency of HCl was comparatively high in almost all heavy metals, and at 0.3N concentration it was the highest. After soil washing process by the use of EDTA, the great part of exchangeable fractions and most of heavy metals of weakly adsorbed like carbonate fraction were extracted. For washing with citrate and HCl, four heavy metals showed the similar exchange of chemical partitioning and the exchangeable fractions of Pb which has weakly adsorbed to soil were more increased than before the process. As removal efficiency of citrate washing process depends upon the distribution of non-detrital fractions, so it can be contended that only the amount of non-detrital fractions could be removed from all the heavy metal content. EDTA and HCl could remove most of non-residual fractions in all heavy metals except Zn. As a result of EDTA washing, toxicity characteristic leaching procedure(TCLP) concentration of the processed soil met the USEPA Pb limit of 5.0 mg/L.

Low Temperature Synthesis of BaCeO3 Nano Powders by the Citrate Process (Citrate Process를 이용한 BaCeO3 나노 분말의 저온 합성)

  • Lee, Dong-Wook;Won, Jong-Han;Joo, Kyoung;Kim, Chang-Yeoul;Shim, Kwang-Bo
    • Journal of the Korean Ceramic Society
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    • v.39 no.6
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    • pp.604-609
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    • 2002
  • Nanosized $BaCeO_3$ powders with the stoichiometric composition of a molecular level were synthesized by the citrate process based on the Pechini method. Polymeric precursor was formed by use of citric acid and ethylen glycol, as chelating agent of metal ions and reaction medium, respectively. Single phase orthorhombic structured $BaCeO_3$powders, about 100 nm sized and uniform shaped were obtained through the calcination of the polymeric precursor at $900^{\circ}C$ for 4 h. Extremely small quantities of carbonate ions($CO_^{2-}$) were completely decomposed at over $1100^{\circ}C$. The mean size of the powders was increased twice, however, it has very uniform distribution in its size and shape.

Low Temperature Synthesis of the Microwave Dielectric (Pb0.5Ca0.5)(Fe0.5Nb0.5)O3 Nano Powders by the Metal-citrate Process (Metal-citrate Process를 이용한 마이크로파 유전체용 (Pb0.5Ca0.5)(Fe0.5Nb0.5)O3 나노 분말의 저온 합성)

  • Lee, Dong-Wook;Won, Jong-Han;Shim, Kwang-Bo;Kang, Seung-Gu;Hyun, Boo-Sung
    • Journal of the Korean Ceramic Society
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    • v.39 no.11
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    • pp.1113-1118
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    • 2002
  • Nano sized $(Pb_{0.5}Ca_{0.5})(Fe_{0.5}Nb_{0.5})O_3$ (PCFN) powders with the stoichiometric composition and the uniform size distribution were successfully synthesized by the metal-citrate process through the calcination of the polymeric precursor which consisted of the metal ions and the organic network. The crystallization of the initial amorphous powders began at $400{\circ}$ and completed at $700{\circ}$. The pyrochlore phase was detected caused by the dissociation of PbO above $900{\circ}$. Single phase perovskite PCFN powders with 40 nm size and uniform shape were obtained through the calcination at $700{\circ}$.

Effect of Lidocaine on Utilization of Endogenous Substrates for Contractile Process of Isolated Rat Atria (심근 수축에 쓰여지는 내인성 기질 대사에 대한 Lidocaine의 영향)

  • Ko Kye-Chang
    • The Korean Journal of Pharmacology
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    • v.31 no.1
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    • pp.53-61
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    • 1995
  • The experiments were performed to determine whether the cardiac depressant action of lidocaine is directly associated with the utilization of endogenous substrates in isolated rat atria, by using citrate and bicarbonate-free medium known as potent inhibitors of phosphofructokinases (PFK) enzyme step. Citrate and bicarbonate-free medium produced negative inotropic action of isolated rat atria incubated in normal Krebs-Ringer bicarbonate glucose medium. Pyruvate and acetate increased the force of contraction of atria depressed by citrate or bicarbonate-free medium, whereas fructose was without effect indicating the inhibitory effect of citrate and bicarbonate-free medium at some point in the glycolytic pathway such as the PFK step in atria. In the absence of exogenous substrate, citrate and bicarbonate-free medium produced a marked depression of the force of substrate-depleted atria indicating that utilization of endogenous substrate above the PFK step, probably cardiac glycogen, is also impaired by citrate or bicarbonate-free medium. Lidocaine produced further depression of the contractile force of atria depressed by citrate. These results argue strongly for an additional mechanism of cardiac depression caused by lidocaine involving the sites below the PFK.

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The Effect of CTAB on the Citrate Sol-gel Process for the Synthesis of Sodium Beta-Alumina Nano-Powders

  • Wang, Zaihua;Li, Xinjun;Feng, Ziping
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1310-1314
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    • 2011
  • Sodium beta-alumina (SBA) nano-powders were synthesized by the citrate sol-gel process, and the effects of the cationic surfactant n-cetyltrimethylammonium bromide surfactant (CTAB) were investigated. The structure and morphology of the nano-powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques, respectively. The effects of CTAB on the citrate sol-gel process and the SBA formation were investigated by thermo gravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared spectroscopy (FTIR). The conductivity of ceramic pellets of SBA was measured by electrochemical impedance spectroscopy (EIS). The results showed that the CTAB inhibited the agglomeration of SBA powders effectively and consequently decreased the crystallization temperature of SBA, about $150^{\circ}C$ lower than that of the sample without CTAB. The measured conductivity of SBA was $1.21{\times}10^{-2}S{\cdot}cm^{-1}$ at $300^{\circ}C$.

A case of Combined Pregnancy in an Ovulation Cycle which has been Induced by Clomiphene Citrate (Clomiphene Citrate로 유도된 배란유도주기에서 발생된 병합임신 1례)

  • Park, Sang-In;Kim, Yong-Man;Suh, Byung-Hee;Lee, Jae-Hyun
    • Clinical and Experimental Reproductive Medicine
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    • v.15 no.2
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    • pp.129-133
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    • 1988
  • Combined (intra and extrauterine) pregnancy refers to impregnations of two different ova at intrauterine and extrauterine sites simultaneously or within a short time interval each other. It is a rare clinical entity and freqently missed in early diagnosis in most instances. Its incidence rate is about 1 in 30,000 pregnancies and the incidence was rised in cases of using ovulation induced agents. The diagnostic rate is less than 10% at early process of the disease. We experienced a case of intrauterine and left tubal pregnancy as combined pregnaney in ovulation cycle which had been induced by clomiphene citrate and now present it with brief review of related leteratures.

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