聚偏氟乙烯中空纤维超滤膜的超声辅助清洗及反冲清洗

STUDY ON PVDF HOLLOW FIBER ULTRAFITRATION MEMBRANE FLUX AND RECOVERY WITH ULTRASOUND AND BACKWASHING

聚偏氟乙烯中空纤维膜(PVDF)在处理污水过程中容易积垢、堵塞膜孔,因而在生产中必须经常进行膜清洗,但清洗效果不能令人满意。对PVDF膜进行了超声辅助清洗试验。得出超声波声强大、清洗效果好的结论,但是声强超过3000W·m-2时,会破坏有机膜的结构。用10%的次氯酸钠溶液浸泡清洗的最佳时间为4h,膜通量恢复率为24.4%;而在相同溶液浓度、相同时间下,利用超声辅助清洗,通量恢复率则达到62.3%。反冲清洗试验中,在无超声条件下,清洗90min,通量提高到26.3L·h-1·m-2,通量恢复率为21.8%;当开启声强为2500W·m-2的超声,清洗相同时间后,膜通量为39.3L·h-1·m-2,通量恢复率为81.9%,明显好于未使用超声时的效果。

Polyvinylidene-fluoride （PVDF） hollow fiber ultrafitration membrane which applied in the wastewater treatment must be cleaned frequently due to its incrustation and blockage of the membrane pores, while the present cleaning methods were not satisfied. Ultrasound was employed to assist PVDF hollow fiber membrane backwashing. The higher intensity of ultrasound leads to the better the cleaning result. While the ultrasonic intensity was more than 3000 W·m^-2, it would destroy the structure of membrane. With the optimum dipping time 4 h, the flux improvement was 24.4% or 62.3% without or with ultrasound treatment respectively. At the operation condition without ultrasound, the membrane was backwashed for 90 min, the flux reached 26.3 L·h^-1·m^-2 and the flux improvement was 21.8%. However, with intensity of 2500 W·m^-2 ultrasound, the flux was up to 39.3 L·h^-1·m^-2, which increased 81.9% than the original membrane.