Membrane capacity and fouling mechanisms for ultrathin nanomembranes in dead-end filtration
Membrane capacity and fouling mechanisms for ultrathin nanomembranes in dead-end filtration
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DOI：
10.1016/j.memsci.2015.10.053
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发表时间：
2016-02
影响因子：
9.5
通讯作者：
J. Winans;Karl J. P. Smith;T. Gaborski;J. Roussie;J. McGrath
中科院分区：
文献类型：
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作者：
J. Winans;Karl J. P. Smith;T. Gaborski;J. Roussie;J. McGrath
超薄膜技术有望改善基于膜的分离，但是关于这些膜支持实际过滤过程的能力还有很多东西需要了解。在这里，我们使用不同的方法来产生跨膜压力，同时改变纳米颗粒的类型、尺寸和浓度，研究了新型纳米多孔氮化硅 (NPN) 膜在死端过滤中的性能。我们通过一分钟死端过滤后产生的滤液量来推断膜污染，并表明这些参数中的每一个对 NPN 污染率都有很大的影响。与正向离心相比，反向离心可在溶剂通过时将大颗粒和聚集体从膜上拉离，从而增加滤液体积。将过滤结果与经典结垢模型进行拟合表明，在所有浓度下，大于孔的颗粒似乎会通过滤饼形成而污染膜，而比孔小得多的颗粒的过滤会在滤饼形成之前受到孔阻塞的影响。通过在离心机设备中的直接比较，我们表明，NPN 膜通过死端过滤以相似的溶剂速度处理小胶体悬浮液的能力与较厚的聚碳酸酯径迹蚀刻膜相当，即使渗透率高出两个数量级以上。
Ultrathin membrane technologies hold promise for improvements in membrane-based separation, however much remains to be learned about the ability of these membranes to support practical filtration processes. Here we examine the performance of new nanoporous silicon nitride (NPN) membranes in dead-end filtration using different methods for generating transmembrane pressure while varying nanoparticle types, sizes and concentrations. We infer membrane fouling by the amount of filtrate generated after a minute of dead-end filtration and show that each of these parameters has a strong influence on the rate of NPN fouling. Inverted centrifugation, which pulls large particles and aggregates away from the membrane as solvent passes through, increases filtrate volumes compared to forward centrifugation. Fitting filtration results to classic fouling models indicate that particles larger than the pores appear to foul membranesviacake formation at all concentrations, while filtration with particles much smaller than pores are impacted by pore obstruction before cake build up. Using direct comparisons in centrifuge devices, we show that NPN membranes have a comparable capacity to process suspensions of small colloids by dead end filtration at similar solvent speeds to thicker polycarbonate track-etched membranes, even with permeabilities more than two orders of magnitude higher.