陶瓷膜过滤收获微藻的效能与膜污染特征

摘要

考察了平板陶瓷膜在次临界通量条件下多周期过滤收获小球藻细胞的效能以及跨膜压差、阻力构成、不可逆污染组分等膜污染特征.结果表明,次临界通量条件下,采用孔径100 nm的陶瓷膜多周期过滤能够有效收获普通小球藻.84%~98%的进水藻细胞以滤饼层方式被截留,通过物理清洗膜表面能够获得高浓度藻液,浓缩因子高于34.3个过滤周期内膜污染均呈现先缓慢增加后急剧升高的两阶段变化趋势.随过滤周期增加,膜污染急剧升高阶段显著加速,其主要原因是小球藻细胞及其EOM形成的协同污染效应以及水力不可逆污染的逐渐累积.水力不可逆污染组分的有机物分子量特征是100~1 000 Da的低分子酸以及1~10 kDa的蛋白类有机物,其中多种芳香族类蛋白和可溶性微生物产物是主要组分.%The performance of a bench-scale ultrafiltration system with a submerged flat-sheet ceramic membrane was investigated for harvesting green microalgae,Chlorella vulgaris.The membrane fouling characterizations,including trans-membrane pressure,components of membrane fouling resistance and the constituents of the irreversible fouling,were systematically analyzed.The results showed that this system had a sound harvesting performance on Chlorella vulgaris.More than 84% of the microalgae in the influent were intercepted on the membrane surface and formed on the cake layer,which could be collected by physical cleaning to a concentrated microalgae liquid with a concentration factor higher than 34.The membrane fouling performance could be divided into two phases,an initial slow increasing phase followed by a quick increasing phase.The latter phase was accelerated with extended filtration cycles.The synergetic fouling effect of algal cells and EOM as well as the increase in the hydraulic irreversible fouling were attributed to the rapid membrane resistance increase.The substances with low molecular weight of 100~1 000 Da and high MW of 1~10 kDa,containing multi aromatic proteins and the soluble microbial products,were the major contributors to the hydraulic irreversible fouling.