响应曲面法优化纳米氯化钙/PVDF杂化膜制备工艺的研究

利用热致相变法制备了纳米氯化钙/PVDF杂化膜,研究了不同添加量的纳米氯化钙粒子对PVDF微孔膜的膜形态、截留率、水通量以及膜强度的影响。采用响应曲面的分析方法,以PVDF膜的水通量以及膜强度为响应值,确定了最佳的纳米CaCl2粒子的添加量、PVDF的质量分数以及凝固浴温度。结果表明:纳米氯化钙的添加能显著改变PVDF膜的形态结构,随着纳米氯化钙含量的增加,海绵状孔逐渐消失,膜表面出现了大量的界面孔,膜通量以及膜强度先上升后下降,而其对截留率的影响较小,在其质量分数为5%时,截留率以及水通量达到最大值。确定的高强度膜制备工艺条件:CaCl2以及PVDF的质量分数分别为4.7%、44%,凝固温度为49.5℃,该条件下,膜截留率达到了75%,水通量达到了174L·m-2·h-1,膜强度则为29.8MPa。 

Optimization of preparation process of nano calcium chloride /PVDF hybrid membrane by response surface methodology

The nano calcium chloride /PVDF hybrid membrane was prepared via thermally induced phase separation, the microporous PVDF membranes morphology, retention rate, the water flux and the film strength under different content of nano calcium chloride were studied.Taking the water flux and the film strength as the response value, the optimum content of nano-particles of CaCl2, PVDF and the coagulation bath temperature were found through the response surface method.The results showed that the addition of nano calcium chloride could obviously chang the morphology of the PVDF membrane.With the increasing content of nano calcium chloride, the sponge-like holes gradually disappeared, a lot of film surface interface holes generated, the membrane flux and film strength increased, and then decreased, while its rejection rate was less affected, when the mass fraction of nanoparticle calcium chloride was 5%, the water flux and rejection rate reached a maximum.The optimum process conditions of high strength film were the content of nano calcium chloride and PVDF were respectively 4.7%, 44%, the solidification temperature was 49.5℃.Under this condition, the membrane rejection rate, the water flux and the film strength were respectively reached 75%, 174L·m- 2·h- 1and 29.8MPa.