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Volume 26, Issue 1
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[in Japanese]1972 Volume 26 Issue 1 Pages 3-10
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSDownload PDF (5953K) -
Takashi NAKANE, Seiichi ISHIZAKA1972 Volume 26 Issue 1 Pages 11-15
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSIn order to study the applicability of reverse osmosis technique to the removal of harmfull metalions from the waste water of mines, factories ane others, a funamental experiment was carried out on the membrane separation of properties of some chloride and sulfate salts contained in aqueous dilute soiutions. For this experiment was used a bached type reverse osmosis test apparatus combined with ‘loose’ Loeb type cellullose acetate semipermeable membranes which were cured at 75°C and 80°C. In case the membrane cured at 75°C and having the salt rejection of 75 percent for aqueous sodium chloride solution was tested by the applied pressure of 4o atm with 0.01mol/l feed solutions, the salt rejections of zinc, manganese, cadmium, cupper and nickel sulfates were more than 98.7 percent, and the fluxes were about 1.05m3/m2/day. Under the same conditions, the membrane rejected about 93 percent of chlorldes of these heavy metals with the fluxes of about 0.9m3/m2/day.The membrane cured at 80°C resulted the salt rejections of more than 99.7 percent ane the fluxes of less than 0.8m3/m2/day for these heavy metal sulfates. It was observed that the membrane permeation of these sulfate salts was due to purely diffusive transport, and a volumetric flow combined with diffusion also contributed to the permeation of chloride salts.View full abstractDownload PDF (3216K) -
Masao MOTOYAMA, Minoru KADOTA, Shumpei OKA1972 Volume 26 Issue 1 Pages 16-20
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe following approximation equations were prepared from the data on the solubility of sodiumchloride in the three ternary systems of NaCl-KCl-H2O, NaCl-MgCl2-H2O, and NaCl-CaCl2-H2O to estimate the solubilities in weight percentage of salts in the quinary system of NaCl-KCl-MgCl2-CaCl2-H2O saturated with NaCl at 25°C: Nacl=26.43-104.0 (n-3.45n3.33)(I) KCL=195.7nx/x+2.06y+1.76z (II) Mgcl2195.7ny/x+2.06y+1.76z (II) Cacl2 =195.7nz/x+2.06y+1.76z (IV) where n is the sum of the numbers of moles of K2Cl2 with the correction term of 0.762, moles ofMgCl2 and CaCl2 in 100 grams of solution, i.e.n=Σ (0.762K2Cl2+MgCl2+CaCl2) moles/100 g soln., and x, y, z are the weight fractions of KCl, MgCl2 and CaCl2. To verify these equations by experiments, three series of solutions containing the salts with theratios by weight of KCI, MgCl2 and CaCl2 of about 3:1:1, 1:3:1 and 1:1:3 were made, andsaturated with NaCl at 25±0.02°C and then analyzed.The solubilities were found to agree with that calculated by the equations (I)-(IV) within the errors at ±0.15 wt% for NaCl and ±0.03wt % for the other salts. Thus the validity of the equations were varified.View full abstractDownload PDF (3097K) -
Scale Formation in Concentrating Sea Water with Ion Exchange Membrane Method (Part III)Nagaaki TAKEMOTO1972 Volume 26 Issue 1 Pages 21-26
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe author made a study on the effects of addition of hydrochloric acid to sea water upon the pH and concentration of carbonates (CO2-FHCO3-+CO3- -) in dialysates and upon the other results of sea water concentration by electrodialysis with ion exchange membrane. The results obtained were as follows:
1. In case HCl was added, the pH of sea water showed a rapid decline at pH > 4, but a gradual decline at pH<4.
2. The pH of desalted solution was 0-0.7 over that of acidic raw sea water, and the pH of concentrated solution was 0.3-1.4 lower.
3. The concentration of carbonates indicated an effective decrease by lowering the pH of both the sea water and the desalted solution to about 6 and the pH of concentrated solution to about 5.The further decline of pH was less effective for decreasing the concentration of carbonates.
4. The acidification of sea water to pH 4.5-5.5 seemed preferable for decreasing the concentration of carbonates in the concentrated solution. In this case, about 50-70g-HCl/m3-sea water was necessary, and the concentration of the carbonates in the concetrated solution decreased to 0.4-0.55×10-3 mol/l. This was about one-fifth to one-seventh when the sea water with no acid added was concentrated.
5. When the pH of raw sea water declined, there were observed lower current efficiency of electrodialysis (for total salts), lower permeabilities of divalent cations and higher permeability of sulfate.View full abstractDownload PDF (3935K) -
Scale Formation in Concentrating Sea Water with Ion Exchange Membrane Method (Part IV)Nagaaki TAKEMOTO1972 Volume 26 Issue 1 Pages 26-32
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSIn case sea water is concentrated by ion exchange membrane method, an improvement in the utilization ratio of sea water which is intended to lower the cost of salt production promotes the probability of scale deposition. The author estimated utilization ratio of sea water for CaCO3 scale deposition from the expulsion process of sea water components by the method he had previously reported, and he confirmed the results of his estimation by experiment. The results of the experimentwere as follows:
1. It was observed that carbonates (CO2+HCO3-+CO3--) in sea water showed a sudden increase in their permeability during their expulsion process. In case the temperature was higher, this phenomenon tended to occur at an early stage of the expulsion process.
2. When this phenomenon occurred, there was observed an abrupt gain in the concentration of CaCO3 on the concetrating surface of anion exchange membrane. Thus, the consequent deposition of the scale was predicted.
3. The limited utilization ratio of sea water for CaCO3 scale deposition was estimated at φUCl=0.4-0.5, and this indicated a probability, of scale deposition without the decomposition of water.
4. The experiment of some 100 hours clarified that the limited utilization ratio of sea water was 0.5-0.55. This fairly agreed with the estimated value.
5. Crystals of CaCO3 scale deposited were Aragonite in elliptical figure in any cases.View full abstractDownload PDF (5012K) -
Scale Formation in Concentrating Sea Water with Ion Exchange Membrane Method (Part V)Nagaaki TAKEMOTO1972 Volume 26 Issue 1 Pages 32-37
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe autor has previously reported that when sea water is concentrated by ion exchange membrane method, there is a probability for calcium carbonate to form scale without occurrence of water decomposition due to abnormal behavior of carbonates (CO2+HCO3-+CO3--) in migration.
In this report, the author made a study on the behavior of carbonates by examining the relations between their behavior and the water decomposition and changes in the current efficiency of hydrogen carbonate ion transport through anion exchange membrane with varied current density. The results were as follows:
1. In electrodialysis of mixed solution of NaCl and NaHCO3, the permeability of carbonates indicated a sudden increase at high current density prior to the decomposition of water. This seemed to show occurrence of decomposition of HCO3-→H+CO3-- (decomposition of carbonates) similar to the decomposition of water.
2. In electrodialysis of NaHCO3 solution, there were two stages of variation in the current efficiency to HCO3 transport at 0.8-0.9 and 0.4-0.5. This seemed to be evidence the occurrence of the decomposition of carbonates mentioned above.
3. In the experiment of 2, the limiting current density for the decomposition of carbonates (ICO2-lim) seemed to be proportional to the concentration of solution at desalting compartment as in the case of water decomposition.View full abstractDownload PDF (3874K) -
Studies on Permselectivity through Ion Exchange Membrane (V)Shoni AZECHI, Hideo YAMAMOTO, Satoshi NAGATSUKA, Masao AKIYAMA, Yosio ...1972 Volume 26 Issue 1 Pages 38-48
Published: 1972
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe authors carried out an experiment to examine what effects those reagents, which were added to feed sea water so as to provide the low- permselectivity of bivalent cations to cation exchange membrane, would exert on concentration characteristics when sea water was concentrated by ion exchange membrane method. For this experiment, an electrodialysis apparatus having an effective area of 5 dm2 was used. Also, larger apparatus (115 dm2) was used to examine its practical use on industrial scale. The results from this experiment were as follows:
1. There was not much difference in effects between the reagent solution α and β.
2. The voltage of the cell showed a decline in line with a rise in the ratio of sodium chloride content to total salt in brine. Accordingly, the consumption of electric energy for electrodialysis indicated a remarkable decrease.
3. The permselectivity coefficient of potassium univalent ion through cation membrane decreased also in proportion to an increase in sodium chloride ratio.
4. Relations between the current density and the concentration characteristics or the permselectivity coefficients were similar to the usual membranes having low-permselectivity for bivalent cations.
5. Under the condition that the current density was 2.6 A/dm2 and the pH value of feed sea water was 6, it was posible to maintain the ratio of sodium chloride in the brine (herein expressed as Cl- Ca-Mg (N) ×100/Cl(N) for convenience) in the range of 93% to 96% by adding successively 0.05-0.5 ppm of the reagent α to the feed sea water. The more the reagent was added to the sea water, the higher the ratio of the sodium chloride in the brine became.
6. The ratio of the sodium chloride increased in proportion to a decrease in the pH value of the feed sea water.View full abstractDownload PDF (6874K)
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