酚类分子结构和纳滤膜特性对截留率的影响规律

EFFECTS OF MOLECULAR STRUCTURES OF PHENOLS AND PROPERTIES OF NANOFILTRATION MEMBRANES ON REJECTION

选择21种酚类化合物作为模型污染物,分别测定了三种不同纳滤膜对酚类化合物的截留率.结果表明,酚类化合物截留率受到取代基位置、种类和膜特性的影响.对NF270膜和NF膜而言,截留率从大到小的次序为邻位>间位>对位,而NF90膜的截留率为邻位>对位;供电子取代基有增大截留率的趋势,吸电子取代基有减小截留率的趋势;孔径小、荷电量大的纳滤膜截留率更大.通过基于遗传算法的偏最小二乘回归法(GA-PLS),建立了纳滤膜对酚类化合物截留率的定量构效关系模型,通过分析回归方程,可以看出酚类化合物的pKa值对截留率影响最大,影响较大的还有偶极矩等参数.

The rejections of 21 phenols by three nanofiltration membranes were tested by experiments, and the results showed that the rejections were affected by the positions and kinds of substituents and properties of nanofiltration membranes:the order for NF270 and NF membranes was ortho- > meta- > para-, and for NF90 membrane it was ortho- > para-; electron-donating substituents had the trend that increased the rejection, while electron-withdrawing substituents had the trend that decreased the rejection; the membrane which had smaller pore radius and more charges had a higher rejection. Quantitative structure-property relationships were developed by PLS combined with genetic algorithm. Based on the regression equations, pKa was the premier factor impacting on rejection, and other factors such as dipole moment were also important.