• Title, Summary, Keyword: Pitzer

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Comparison of Ionic Equilibria Analysis of ZnSO4-Fe2(SO4)3-Na2SO4-H2SO4-NaOH-H2O System at 25℃ between Pitzer and Vasil'ev Equation (25℃에서 ZnSO4-Fe2(SO4)3-Na2SO4-H2SO4-NaOH-H2O계에 대해 Pitzer식과 Vasil'ev식에 의한 이온평형해석 비교)

  • Lee, Man-Seung;Lee, Kyoung-Ju;Nam, Sang-Ho
    • Analytical Science and Technology
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    • v.16 no.2
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    • pp.159-165
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    • 2003
  • To develop an ionic equilibria model applicable to the sulfuric acid leaching solutions of zinc oxide ore, the method of the Pitzer equation and that of the Vasil'ev equation were compared. As the ionic strength of the solution increased to 9 m, the results of ionic equilibria by the Pitzer equation were more accurate than those by Vasil'ev. To simulate the sulfuric acid leaching solutions of zinc oxide ore, the mixed solutions with the various composition of $ZnSO_4-Fe_2(SO_4)_3-Na_2SO_4-H_2SO_4-NaOH-H_2O$ were prepared. The pH values calculated in this study agreed well with those measured at $25^{\circ}C$.

Ionic Equilibria in $ZnSO_4-Na_2SO_4-H_2SO_4-NaOH-H_2O$ System ($ZnSO_4-Na_2SO_4-H_2SO_4-NaOH-H_2O$계의 이온 평형)

  • 이만승;박현주;나춘기
    • Journal of the Korean Institute of Resources Recycling
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    • v.11 no.1
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    • pp.19-25
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    • 2002
  • For $ZnSO_4$-$Na_2$$SO_4$-$H_2$ $SO_4$-$NaOH-H_2$O system, pH of solutions with different electrolyte concentrations was measured at $25^{\circ}C$ and ionic equilibria were analyzed by using K-value method. Activity of water and activity coefficients of solutes were calculated by Pitzer equation. The equilibrium concentration and activity coefficients of solutes were calculated from initial experimental conditions. At high ionic strength of 4m, the pH values calculated were in good agreement with those measured. In the experimental ranges of ionic strength of solution from 3.5 to 4.3 m, the mean activity coefcient of $ZnSO_4$calculated agreed well with those obtained from literature.

Measurement of Solubilities in the Ternary System NaCl + CaCl2 + H2O and KCl + CaCl2 + H2O at 50℃ (NaCl + CaCl2 + H2O 및 KCl + CaCl2 + H2O 삼성분계에 대한 50℃에서의 용해도 측정)

  • Yang, Ji-Min;Hou, Guang-Yue;Ding, Tian-Rong;Kou, Peng
    • Journal of the Korean Chemical Society
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    • v.54 no.3
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    • pp.269-274
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    • 2010
  • The solubility and the physicochemical property (refractive index) in the NaCl-$CaCl_2$-$H_2O$ and KCl-$CaCl_2$-$H_2O$ systems were determined at $50^{\circ}C$ and the phase diagrams and the diagrams of physicochemical property vs composition were plotted. One invariant point, two univariant curves, and two crystallization zones, corresponding to sodium Chloride (or potassium chloride), dihydrate ($CaCl_2{\cdot}2H_2O$) showed up in the phase diagrams of the ternary systems. The mixing parameters ${\theta}_{M,Ca}$ and ${\Psi}_{M,Ca,Cl}$ (M = Na or K) and equilibrium constant $K_{sp}$ were evaluated in NaCl-$CaCl_2-H_2O$ and KCl-$CaCl_2-H_2O$ systems by least-squares optimization procedure, in which the single-salt Pitzer parameters of NaCl, KCl and $CaCl_2$ ${\beta}^{(0)}$, ${\beta}^{(1)}$, ${\beta}^{(2)}$ and $C^{\Phi}$ were directly calculated from the literature. The results obtained were in good agreement with the experimental data.

Effect of Precipitation on Operation Range of the CO2 Capture Process using Ammonia Water Absorbent (암모니아수 흡수제를 이용한 이산화탄소 제거 공정에서 침전생성이 조업영역에 미치는 영향)

  • You, Jong Kyun;Park, Ho Seok;Hong, Won Hi;Park, Jongkee;Kim, Jong-Nam
    • Korean Chemical Engineering Research
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    • v.45 no.3
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    • pp.258-263
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    • 2007
  • Ammonia water was investigated as a new absorbent of the chemical absorption process for the removal of $CO_2$ in flue gas. The suitable range of ammonia water concentration and $CO_2$ loading ($mol\;CO_2/mol\;NH_3$) were decided in the point of view of $CO_2$ absorption capacity and $NH_4HCO_3$ precipitation. The absorption capacity of $CO_2$ and the precipitation of $NH_4HCO_3$ in liquid phase were calculated by the Pitzer model for electrolyte solution. The $CO_2$ absorption capacity of the ammonia water over $5\;molNH_3/kgH_2O$ was higher than that of conventional amine absorbent. The $CO_2$ loadings where precipitation occurred were decided at various absorbent concentrations. Theses values were higher than 0.5 in the concentration range of $5-14\;molNH_3/kgH_2O$ at 293, 313 K. The absorber for the removal of $CO_2$ in flue gas could be operated without $NH_4HCO_3$ precipitation by using high concentration of ammonia water below these $CO_2$ loading values. The optimum temperature of the ammonia water absorbent for removal of $CO_2$ in flue gas was 297-312 K depending on the concentration of ammonia water.

Scaling predictions in seawater reverse osmosis desalination

  • Hchaichi, Houda;Siwar, Saanoun;Elfil, Hamza;Hannachi, Ahmed
    • Membrane Water Treatment
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    • v.5 no.3
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    • pp.221-233
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    • 2014
  • Simulations were conducted to predict supersaturation along Reverse Osmosis (RO) modules for seawater desalination. The modeling approach is based on the use of conservation principles and chemical equilibria equations along RO modules. Full Pitzer ion interactive forces model for concentrated solutions was implement to calculate activity coefficients. An average rejection rate for all ionic species was considered. Supersaturation has been used to assess scaling. Supersaturations with respect to all calcium carbonate forms and calcium sulfate were calculated up to 50% recovery rate in seawater RO desalination. The results for four different seawater qualities are shown. The predictions were in a good agreement with the experimental results.

Marine macroalgae of the Aleutian Islands: I. Bangiales

  • Lindstrom, Sandra C.;Lindeberg, Mandy R.;Guthrie, Daniel A.
    • ALGAE
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    • v.30 no.4
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    • pp.247-263
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    • 2015
  • We sequenced the rbcL gene in more than 100 collections of foliose Bangiales made in the Aleutian Islands and western Alaska Peninsula during the past 25 years. This work allows us to recognize four previously undescribed species, two in the genus Boreophyllum and two in Pyropia. Boreophyllum aleuticum appears to be endemic to the Aleutian Islands, whereas B. ambiguum is known to occur from the Yakutat area to the tip of the Alaska Peninsula. The two previously undescribed species of Pyropia are more broadly distributed. Pyropia taeniata, which was previously identified under the name Py. pseudolinearis, occurs from northern Southeast Alaska through the Aleutian Islands. Pyropia unabbottiae, which is sister to Py. abbottiae, occurs from southern Vancouver Island to Attu Island. Collections throughout the Aleutian Islands allow us to document the distribution of another dozen species of foliose Bangiales in this region, including Boreophyllum aestivale, Fuscifolium tasa, Pyropia fallax, Py. fucicola, Py. gardneri, Py. kurogii, Py. nereocystis, Py. pseudolanceolata, Py. torta, Wildemania amplissima, W. norrisii, and W. variegata. We were unable to confirm the occurrence of the following species previously recorded from the Aleutian Islands: Porphya ochotensis, Pyropia abbottiae, Py. perforata, Py. pseudolinearis, P. purpurea, P. umbilicalis, Py. yezoensis and Wildemania schizophylla. At least two undescribed filamentous Bangiales also occur in the Aleutian Islands.

Solvent Extraction of Cuprous and Cupric Chloride from Hydrochloric Acid Solutions by Alamine336 (염산용액에서 Alamine336에 의한 염화 제1, 2구리의 용매추출)

  • Lee, Man-seung;Lee, Jin-Young
    • Korean Journal of Metals and Materials
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    • v.47 no.5
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    • pp.297-303
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    • 2009
  • Solvent extraction experiments of cupric and cuprous chloride with Alamine336 have been performed from HCl solution. In order to identify the solvent extraction reaction, distribution diagram of cupric and cuprous species with HCl concentration was obtained by considering complex formation reaction and the activity coefficient of solutes with Pitzer equation. Analysis of the solvent extraction data by graphical method together with the distribution diagram of copper indicated that solvent extraction reaction of copper with Alamine336 depends on HCl concentration. In strong HCl solution of 3 and 5 M, ${CuCl_4}^{2-}$ and ${CuCl_3}^{2-}$ took part in the solvent extraction reaction as Cu(II) and Cu(I), respectively. When HCl concentration was 1 M, ${CuCl_2}^-$ was extracted into the organic phase in the case of Cu(I) while adduct formation between $Cu^{2+}$ and Alamine336 was responsible for the solvent extraction reaction of Cu(II).