藻类对纳滤膜去除萘普生的影响

Influence of Algogenic Organic Matter on Naproxen Removal by NF-Membrane

传统的饮用水处理工艺不能有效地去除水中痕量有机物PPCPs,纳滤(NF)膜工艺对其有较好的去除效果。水中有机物(DOM)的存在对NF膜去除PPCPs有较大的影响,藻类有机物(AOM)的组成及特性不同于天然有机物,它在膜处理工艺中对膜污染有重要的影响。试验研究了2种藻类(鱼腥藻、小球藻)AOM对纳滤膜去除萘普生(NPX)的影响效果。结果显示2种藻类AOM均能促进NF膜对NPX的分离,提高NPX的去除率,但会显著降低膜通量。AOM的分子量分布和亲疏水性与其对NPX去除率的影响有关,AOM中亲水性的多糖和蛋白类有机物质是造成膜污染和影响NPX去除率的主要物质。滤饼层的形成改变了膜表面的亲疏水性能和截流分子量(MWCO),也是造成膜通量衰减和NPX去除率提高的重要原因。

Nanofiltration （NF） membrane has been used to remove trace organic compounds such as PPCPs in drinking water treatment, but the presence of dissolved organic matter （DOM） in raw water is detrimental to NF membrane in filtrating PPCPs. Furthermore, algogenic organic matter （AOM）, being different from DOM, incurs membrane-fouling. To cope with the problem, the experimental study was conducted, which focused on AOM extracted from two species of algae （Anabaena, Chlorella）and its effects on naproxen （NPX）removal by NF membrane. Findings of the study uncovered that AOM of two algal species could promote separation of NPX by the membrane, enhancing NPX removal from water; however, flux of the membrane was greatly reduced. It was also found that hydrophilic polysacchafide and protein organic matter of AOM were the main organics causing membrane fouling thus affecting NPX removal. In additon, formation of the filter cake layer could alter hydrophilic/hydrophobic properties and molecular weight cut-off （MWCO） of the membrane, thus leading to the increase of NPX removal, and at the same time the decline of membrane flux.