聚偏氟乙烯微滤膜过滤纯生啤酒性能与滤菌效果研究
Study on the performance of PVDF membranes and its degerming effect for application of draft beer filtration
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摘要: 研究了指孔状结构和网状结构的亲水性聚偏氟乙烯(PVDF)微滤膜的滤菌性能与膜结构、膜孔径的关系,探讨了生啤酒过滤过程中膜结构、清洗方式对除菌效果和膜过滤通量的影响规律,通过SEM和接触角测定仪表征了微滤膜的结构和亲水性。结果表明:膜的结构对滤菌效果影响不大;0.22μm数量级的PVDF微滤膜的滤菌效果达到啤酒生产要求;清水清洗和碱、清水、酸、清水连续清洗两种清洗方式对网状结构的PVDF膜影响不大,其平衡过滤通量保持在22.2~22.4L/(m2·h),但碱、清水、酸、清水连续清洗方式更有利于指孔状结构PVDF膜性能的恢复,平衡通量约为40.8L/(m2·h),而同样条件下清水清洗的平衡通量为35.0L/(m2·h)。实验数据表明用亲水性的PVDF微滤膜过滤生啤除菌,仅采用清水清洗膜在操作上是可行的。Abstract: Hydrophilic Poly ( vinylidene fluoride) ( PVDF) microfiltration membranes with finger- like structure and reticular structure were used to filter bacteria. The relationship between the structure and pore size of PVDF membranes and its degerming effect was studied.The influence of membrane structure and clean manner on the degerming effect and filtration flux during draft beer filtration was also investigated.Scanning electron microscope ( SEM) and water contact angle measurer were used to characterize the membrane structure and its hydrophilicity.The results showed that the degerming effect could meet the requirement of draft beer when the pore size grade of PVDF membrane was about 0.22μm for both finger-like structure and reticular structure membranes.There were no significant differences between base- water- acid- water cleaning manner and the water cleaning manner on the recovery of the filtration flux of reticular structure membranes.The draft beer flux for both of the cleaning ways was stable to 22.2 ~ 22.4L / ( m2·h) around. The base- water- acid- water cleaning method was beneficial to the performance of finger-like membranes where the draft beer flux was stable to 40.8L / ( m2·h) .Compared to the base-water-acid- water cleaning way, the draft beer flux was stable to 35.0L / ( m2·h) when the water cleaning method was used. The results indicated that the water cleaning method was available for draft beer filtration degerming when hydrophilic PVDF microfiltration membranes were used in performance.