响应面法在超滤过程分析和评价中的应用

以天然水体中普遍存在的天然有机物腐殖酸(humic acid,HA)为模型污染物,采用PVC合金中空纤维超滤膜去除水中腐殖酸。以腐殖酸去除率和水透过系数作为评价指标,采用响应面法对超滤过程中溶液pH、溶液离子浓度和初始膜通量进行三因素五水平中心组合设计实验,并采用二次回归方程拟合影响因素与响应值之间的函数关系,建立回归方程。结果表明,在腐殖酸的超滤过程中,溶液pH值、溶液离子浓度、初始膜通量对腐殖酸去除率的影响显著性大小为:溶液pH值>溶液离子浓度>初始膜通量,对水透过系数影响显著性大小为:溶液pH值=初始膜通量>溶液离子浓度。腐殖酸去除率和水透过系数方程的调整决定系数Adj. R2分别为为77.10%和88.12%,显著性水平分别为0.001504和0.0001,达到极显著水平,说明方程拟合良好,可用于超滤过程中腐殖酸去除率和水透过系数的分析和评价。

Application of response surface methodology in analysis and evaluation of ultrafiltration process

The ubiquitous natural organic matter humic acid and the PVC hollow-fiber ultrafiltration membrane were used in the ultrafiltration study. The evaluation parameters were humic acid removal rate and water transport coefficient, and solution pH, ion concentration and initial filtration flux were selected as the influencing factors. The response surface methodology with three factors five levels central composite design experiment was applied to investigate the relationships between evaluation parameters and influence factors, and the corresponding quadratic regression equations were established. Results indicated that the significant effects of the influencing factors on humic acid removal rate were:solution pH > ion concentration > initial filtration flux, the significant effects of the influencing factors on water transport coefficient were:solution pH=initial filtration flux > ion concentration; the Adj. R2 level and P-level of quadratic regression equations for humic acid removal rate and water transport coefficient were 77.10%, 88.12% and 0.001504, 0.0001, respectively, which were good analysis and evaluation of the process of ultrafiltration.