亲水疏油改性聚偏氟乙烯膜用于油水分离的实验研究

THE EXPERIMENTAL STUDY OF OIL/WATER SEPARATION BY A MODIFIED POLYVINYLIDENE FLUORIDE MEMBRANE WITH HYDROPHILIC AND OLEOPHOBIC SURFACE PROPERTIES

以聚偏氟乙烯（PVDF）和一种具有亲水疏油性的添加剂为原料制备的新型改性PVDF中空纤维膜为对象,研究了该膜的微观结构、机械强度、表面润湿性,并以错流过滤方式处理配制的含油水（质量浓度400 mg/L）,考察了原液温度、操作压力、浓液回流量等操作条件对其处理过程中通量和截留率的影响。结果表明,操作压力越大,初始通量越大,但通量衰减也越快;原液温度升高,通量随之升高,基本成线性关系;浓液回流量越大,膜的通量越大,且通量衰减程度越小。该亲水疏油膜对含油废水具有优异的分离效果,在进水TOC的质量浓度为300~400 mg/L时,出水中TOC的质量浓度达1~4 mg/L,油分去除率达到99%以上,并仅在水力清洗的情况下就能完全恢复通量。该改性PVDF膜具有用于含油废水处理的潜力。

A novel PVDF hollow fiber membrane was prepared with polyvinylidene fluoride （PVDF） and a modified hydrophilic-oleophobic additive as the starting material. The microstructure, mechanical strength and surface wettablitity of the membrane were investigated. And the effect of original liquid temperature, operation pressure, and retentate flux on the permeability and the TOC removal efficiency was studied under the cross-flow filtration operation for separation of oily wastewater with mass concentration of 400 mg/L. The results demonstrated that the initial permeate flux increased with the increase of operation pressure rising. However, the flux reduced faster; When the temperature rose, the permeate flux increased in linear relationship; The larger the retentate flux was, the greater the permeate flux was, and the flux reduced slower. The membrane with hydrophilicity and oleophobicity had great effectiveness on oil-water separation. When the mass concentration of influent TOC was 300~400 mg/L, the mass concentration of effluent TOC was 1-4 mg/L, the removal efficiency was higher than 99%, and the flux could be fully recovered after a simple cleaning of water wash. The modified PVDF membrane holds a great potential for the treatment of oily wastewater.