Study On Post - Treatment And Retention Performance Of High Performance Hollow Fiber Membrane

Dry-wet spinning hollow fiber membrane prepared in the forming process,the winding tension will produce a certain stretch.The winding of hollow fiber membrane is completed.Then the membrane through the cut condition.However,the membrane will occur some length back reduction.In the subsequent long-term,the membrane immersion in the water for washing or even dipping aqueous glycerol solution,dried, shrink.The membrane is still some length back reduction slowly.During contraction process,the contraction of membrane is equal to microporous hollow fiber membrane structure contract.What’s important,macro indicators corresponding that water flux of hollow fiber membranes will also be accompanied after cutting shrink.And storage time extended,gradually declined.How to post-processing,in the holding spinning microporous hollow fiber membrane process,while the internal stress and the membrane will slack off,which is an important research topic to improve hollow fiber membrane water flux of articles.The paper uses polyvinylidene fluoride and polysulfone hollow fiber membrane for investigating,using scanning electron microscopy,UV spectrophotometer,flux and interception test equipment.Then hollow fiber membrane is stretched to different conditions,heat setting process.The samples were tested before and after analysis.PVDF hollow fiber membrane through water-heat setting process for stretching, which has a certain effect.But the water-heat setting process need long time to heat setting,not suitable for industrial production.Using wind-heat setting process that time can be shortened,and the effect is obvious.The experiment also show that the first step PVDF membrane impregnated in glycerin is necessary.In this experiment the best experimental conditions is:stretching ratio of 20%,hot-wind setting process treat 10 min, heat setting temperature 50℃,membrane water flux ratio increased 87.7%.It is significant that stretching wind-heat stereotypes of polysulfone hollow fiber membrane to improve flux.Experiment with different stretch rates,different wind temperature and sample with a lot of different testing,various process conditions stereotypes time to obtain the best conditions:dipping with glycerol,then pulling stretch ratio of 7%,the wind-heat setting treats 5 min,heat setting temperature with 60℃,which get high flux polysulfone membrane and water flux increased 38.6%.The paper discuss that rejection performance of ultrafiltration membrane test methods, in particular the stability of D reagent in polyethylene glycol.Founding that with the extension of storage time of D reagent,test sample absorbance value increases. And D reagent stored at room temperature change more than in the refrigerator. Therefore,polyethylene glycol as retentate in ultrafiltration membrane for the standard curve.Otherwise,it will have a greater measurement error in supply and demand.Proposing new method with Simple,fast and accurate in testing of polyethylene glycol rejection.Stating the relevant test methods and test conditions in Oceanic Administration industry standard HY/T050-1999.(the test method of hollow fiber ultrafiltration membrane).