辛酸对反渗透膜的污染研究

Research on the pollution of RO membrane by octanoic acid

以辛酸为模型污染物,分析了不同p H及Ca2+存在下辛酸对反渗透膜进水压力、产水TOC及脱盐率的影响。同时考察了海藻酸钠、蛋白质、腐殖酸等典型有机污染物共存时,辛酸在膜污染中的贡献。实验结果表明,当进水p H分别为4、7.5时,进水压力分别在污染运行的8、36 h内上升至初始压力的15%;p H为4时,Ca2+浓度的变化对膜污染无明显影响,产水中的TOC随着运行时间的延长而增加;p H为7.5时,运行时间随Ca2+浓度的增加而延长。不存在Ca2+时,相对海藻酸钠、蛋白质、腐殖酸而言,小分子质量的辛酸是造成膜污染的主要有机物。Ca2+存在时,海藻酸钠取代辛酸成为膜的主要有机污染物。

Using octanoic acid as a kind of model pollutant,the influences of octanoic acid on the influent pressure, TOC in produced water and desalination rate of reverse osmosis membrane have been analyzed under the conditions of different pH and the presence of Ca^2＋. In addition, the contribution of oetanoie acid to membrane fouling in the coexistence of typical organic pollutants, such as alginate, protein, humic acid, etc., has been investigated. The results show that when the pH of the influent are 4 and 7.5 ,respectively,the influent pressure rises to 15% of the initial pressure within 8 h and 36 h, respectively. When pH is 4, the change of Ca^2＋ does not have significant influence on membrane fouling, and TOC in the produced water increases with the increase of operation time. When the pH is 7.5,the operation time is prolonged with the increase of Ca^2＋. In the absence of Ca^2＋, small molecular weight octanoic acid is the main organic substance that causes membrane fouling in relation to alginate,protein and humic acid. In the presence of Ca^2＋, alginate is the main organic pollutant that causes membrane fouling.