响应面优化法在PDMS/PVDF膜制膜条件优化中的应用

用响应面优化法优化了乙烯基封端PDMS/PVDF渗透汽化透醇膜的制膜条件,研究了硅橡胶浓度、B/A质量比、交联温度和交联时间对膜性能的影响,拟合了分离因子、渗透通量与四因素之间的回归方程,并用方差分析法考察了四因素的主效应、二次效应以及相互作用效应对复合膜的分离因子与渗透通量的影响。研究发现,硅橡胶浓度对膜的分离因子与渗透通量的影响最为显著,交联时间对分离因子几乎没有影响。通过对回归方程的优化分析得知,在料液乙醇浓度为10%(wt),操作温度40℃条件下,当硅橡胶浓度为93%(wt),B/A质量比为0.08,交联温度为100℃,交联时间为13.83 h时,膜的综合分离性能达到最佳,此时分离因子与渗透通量预测值分别为9.47、77.57 g(m2 h)1,渗透侧乙醇浓度达到51.3%(wt)。回归方程的验证实验结果表明,回归方程的估计值与实验值较为吻合,可用于乙烯基封端的PDMS/PVDF复合膜的渗透汽化性能的预测与优化。

Application of Response Surface Methodology(RSM) to Optimize the Preparation Conditions of PDMS/PVDF Composite Membranes

The response surface methodology(RSM) was used to optimize the preparation conditions of PDMS/PVDF composite membranes for pervaporation.The effects of four variables including silicone rubber concentration,mass ratio of RTV B to RTV A,cross-linking temperature and time on the membrane performances were investigated.The regression equations between the preparation variables and the performances of the composite membranes were established,and the main effects,quadratic effects and the effects of interactions of the four variables on the separation factor and permeation flux of the composite membranes were studied.It was found that the silicone rubber concentration affects the selectivity and permeation flux of the composite membranes prepared most significantly,while the cross-linking time has almost no effect on the selectivity.According to the optimization analysis of the proposed regressing equation,it was found that,at 40℃ and ethanol concentration of 10%(wt) and when the silicone concentration is 93%(wt),the mass ratio of RTV B to RTV A is 0.08,cross-linking temperature is 100℃ and cross-linking time is 13.83 h,the prepared PDMS/PVDF composite membrane will have the optimum performances of selectivity of 9.47,total flux of 77.57 g(m2·h)-1 and the ethanol concentration of the permeate side is 51.3%.The experimental results are in good agreement with those predicated by the proposed regression equation,which indicates that the proposed regression equation could be used to forecast and optimize the pervaporation performance of the PDMS/PVDF composite membrane to be prepared.