Abstract
Effects of various conditions on the low-permselectivity of permselective reagent (α-solution) were studied by using a unit cell-type apparatus equipped with 300 unit cells of 115dm2 effective membrane-area. Results were obtained as follows.
1. When the concentration of the reagent which was added into feed sea water was larger, the ratio of sodium chloride to the total salt in the obtained brine become greater.
2. When the pH of the feed sea water was lower, the ratio of NaCl showed a linear increase.
3. When the removal ratio of salt (recovery of sodium chloride) of the feed sea water was larger, the ratio of NaCl showed a slight decline.
4. Even if the solution was agitated by blowing air into the diluting chamber of the apparatus, there was observed little difference in the ratio of NaCl.
5. When those foreign matters attached to the surface of the membrane were washed out, there were seen an increase in the ratio of NaCl and a decrease in the voltage drop of the membrane.
6. When the ratio of NaCl expressed by the equation of {(Cl-Ca-Mg)(N)×100/Cl(N)} was below 95%, there was a decline in the voltage drop of the membrane with an increase in the ratio of NaCl. On the other hand, the voltage drop of the membrane showed an increase when the ratio of NaC1 was over 95%.
7. After membrane in the diluting chamber was washed with circulating 0.1 N hydrochloric acid for 4-24 hours, there was observed an increase in the effectiveness of the reagent.
