课题组周宇同学于《Journal of Membrane Science》期刊上发表了题为《Biofouling metallic membranes in algae-laden water treatment: Performance, mechanism, and the role of the pre-coated layer》的论文。
生物污染是限制超滤膜系统在饮用水处理中性能的主要因素。本研究系统地研究了金属膜在处理含藻水的应用效果和生物污染行为，并评估了预涂布层对生物污染的缓解效果和机理。研究结果表明，金属膜基本完全去除藻细胞（>99.99%）和EOM（细胞外有机物）中的大分子有机物，但对EOM中的腐殖酸和富勒酸等小分子有机物的去除效果有限（TOC（总有机碳）和UV254的去除率分别为47.29%和17.72%）。在直接过滤过程中，藻细胞会在金属膜前形成滤饼层，从而降低膜通量，而EOM的存在会使滤饼层更加致密，加速通量的下降。此外，膜的不可逆污染在酸性或富含Ca2+的溶液中会加剧，而藻类细胞颗粒的增加会加剧可逆膜污染，导致通量更快下降。根据膜机理分析，在整个直接过滤过程中，污染机理从孔隙完全堵塞到标准和中间堵塞演变。相比之下，与直接过滤相比，预涂布高岭土层能显著减少膜堵塞。在过滤的早期阶段，预涂布层可以防止污染物与膜表面直接接触，从而推迟了孔隙完全堵塞的阶段。另一方面，XDLVO（Derjaguin-Landau-Verwey-Overbeek）数据显示，高岭土与藻类之间的作用力（-102.323 mJ/m2）大于高岭土与金属膜之间的作用力（-61.424 mJ/m2），因此反冲洗效果更好。这些发现将支持在饮用水处理中使用金属膜。
Abstract: Biofouling is the primary factor limiting the performance of ultrafiltration membrane systems in drinking water treatment. This study systematically investigated the application effect and biofouling behavior of metallic membranes in the treatment of algae-laden water and evaluated the mitigation effect and mechanism of the pre-coated layer on biofouling. The findings demonstrate that the metallic membrane can almost completely remove algal cells (>99.99%) and macromolecular organics in EOM (Extracellular Organic Matter) but has limited effects on micromolecules, such as humic acid and fulvic acid, in EOM (47.29% and 17.72% for TOC (Total Organic Carbon) and UV254, respectively). During direct filtration, algal cells can form a cake layer in front of the metallic membrane to reduce the membrane flux, whereas the presence of EOM makes the cake layer denser and hastens the decline in flux. In addition, irreversible membrane fouling is exasperated in acidic or Ca2+-rich solutions, whereas an increase in algal cell particles exacerbates reversible membrane fouling, causing a faster decline in flux. According to the membrane mechanism analysis, the fouling mechanism ranges from complete pore blocking to standard and intermediate blocking throughout the direct filtration process. In contrast, the application of a pre-coated kaolin layer significantly decreases membrane fouling compared with direct filtration. The pre-coated layer can prevent direct contact between the foulants and the membrane surface during the early stages of filtration, resulting in a delayed complete pore blockage stage. On the other hand, XDLVO (Derjaguin-Landau-Verwey-Overbeek) data reveals that the force between kaolinite and algae (-102.323 mJ/m2) is greater than that between kaolinite and metallic membranes (-61.424 mJ/m2), resulting in better backwashing efficacy. These findings support the use of metallic membranes in drinking water treatment.
Keywords: Metallic membrane; biofouling; algae-laden water; pre-coated layer; kaolin particle
