Dissertation > Industrial Technology > Chemical Industry > General issues > Chemical processes ( physical processes and physical and chemical processes ) > Separation process > New separation method

The Performance Evaluation and Resistance Research of PVDF Hollow Fiber Microfiltration Membrane Products

Author TangXiaoShan
Tutor WangZhi; DaiHaiPing
School Tianjin University
Course Chemical Engineering
Keywords PVDF Hollow Fiber Membrane Properties Evaluations Test Method Drug Resistance
CLC TQ028.8
Type Master's thesis
Year 2012
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The membrane separation technology has already realized industrialization in ourcountry after decades of development. Especially in recent years, the functionalpolymer membrane, as a representative of the membrane separation technology, hasmade remarkable progress. At the same time, microfiltration membrane products arevarious. As the quality of raw materials, the manufacturing capacity, processtechnology level and detection limit, there is a big gap among the micro-filtrationmembrane products. A complete evaluation system of the overall performance ofmicrofiltration product hasn’t been built up and product quality assurance techniqueshasn’t been deeply researched, which affect the promotion of micro-filtrationmembrane technology to a large extent and are not propitious for the trademanagement and the unified regulations of market competition. This papercharacterized the main properties of PVDF hollow fiber membranes produced by wetspinning process, narrated the main meaning of the characterization, researched theevaluation methodology of every performance and relative analyzed the analyticalmethod through example of case. The shape structure, water permeability, porosity,pore size, tensile properties, burst pressure, integrity have been studied in this paper.Through the research of the membrane pore size test method, the optimumcondition during test can be determined and the influencing factors of other conditionson the test results will be clear. The result shows that the suitable soaking liquidshould be chosen during the measurement of pore size and pore size distribution ofdifferent types of hollow fiber membrane. Otherwise, the best length of hollow fibermust be chosen according to the characteristics of the soaking fluid, so that we canmake evaluation and comparison of the pore and pore size distribution of the samples.Treating the hollow fiber membrane with the soaking liquid that is compatible to thefiber material, viz. the contact angleθbetween the membrane material and soakingliquid is approximately 0, the measurement of the pores will be accurate. The soakingliquid should be steady under room temperature, not easy to volatilizable, and has alittle surface tension.In his paper, the evaluation of the new-made hollow fiber membranes was made.Due to the structure is not stable enough, the performance of the fiber membranes will bechanged during storage. The research mainly tracked the dimensions and water permeability of the fiber. The result shows that the dimensions vary as a function of time.The dimension change in the first month was obvious, but it was almost stable in thefuture. The pure water flux decreased during storage. The flux decreasement was obviousin the first month, and it approached stable afterward.Through the study of drug resistance, we defined the influence of acidic cleaningagent, alkaline cleaning agents and oxidizing cleaning agents on membraneperformance. The pure water flux, breaking strength and elongation at break weremainly evaluated. And we put forward the theory equivalent of point concentrationand time(ppm·h) to evaluate the drug resistance, which provide a reference base forthe influence of different drag and time.

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