| 摘要 |
PURPOSE:To recover and reuse high-quality terephthalic acid useful for the synthesis of polyester fibers, from a waste liquid of the thinning process of polyester fiber cloths, by removing the titanium oxide fine powder and various heavy metal ions from the liquid with an untrafiltration membrane. CONSTITUTION:The surface of the fiber polyester fiber cloths is hydrolyzed with an alkali metal hydroxide to improve the rigid feeling of the cloth. The waste liquid discharged from the above process is treated with an ultrafiltration membrane (e.g. ACL-1010, product of Asahi Chemical Ind.) to remove the powdery impurities and/or colloidal impurities, and the pH of the liquid is adjusted to 7-9 to obtain terephthalic acid. Although the titanium oxide particles contained in polyester fibers has particle diameter of 0.2-0.5mu and its amount is <=0.5wt%, it can be removed with an ultrafiltration membrane without causing clogging of the membrane keeping stable rate of permeation. |
