| 摘要 |
PROBLEM TO BE SOLVED: To reduce the water movement amount from the recovery side to the stock solution side and achieve the high acid recovery rate by keeping a stock solution feed chamber in the state of pressure higher than that of an acid recovery chamber by the specified value or more and using an anion exchange membrance of high acid impregnation speed. SOLUTION: A hollow fiber membrane 1 is fixed by a housing 7 with a potting material 6. Stock solution is fed from a stock solution feed opening 2 to the inside of the hollow fiber membrane 1, and recovered acid water solution is permeated through the hollow fiber membrane 1 and collected outside the membrane and discharged from a recovered solution outlet 5 to the outside of a module. Water is fed from a diluting water feed opening 1 to the outside of the hollow fibers to retain the recovered acid concentration constant. The stock solution from which acid is recovered is discharged out of a stock solution outlet 3. As for the operation condition, acid can be recovered efficiently by keeping a stock solution feed side chamber in the state of pressure higher than that of an acid recovery side chamber by 0.1kg/cm<2> or over. The above process is particularly effective in the case of diffusion dialysis using a separating membrane of high acid permeation speed. |
