| 摘要 |
PURPOSE:To remove the contaminants regardless of the kind of a membrane, and to maintain and recover the performance of the membrane by bringing the surface of the membrane into contact with an acid and then with a liquid contg. hydrazine. CONSTITUTION:The surface of a contaminated membrane is brought into contact with an acid to remove a part of the contaminants. An organic acid having a chelating and a reducing action such as oxalic, citric, and tartaric acids are preferably used as said acid. The concn. of the acid is suitably regulated to 0.05-3%, and the pH to 2-4. The membrane is then washed with a liquid contg. hydrazine, and the most of the contaminants which are not removed by the acid washing is removed. The concn., in this case, is preferably regulated to 0.01-1% and the pH to 7.5-10. A surfactant can be preferably added to the acid and/or the liquid contg. hydrazine, and used at 0.001-0.5% concn. |
