Effect of flux (transmembrane pressure) and membrane properties on fouling and rejection of reverse osmosis and nanofiltration membranes treating perfluorooctane sulfonate containing wastewater.
Effect of flux (transmembrane pressure) and membrane properties on fouling and rejection of reverse osmosis and nanofiltration membranes treating perfluorooctane sulfonate containing wastewater.
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DOI：
10.1021/es062052f
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发表时间：
2007-02
影响因子：
11.4
通讯作者：
C. Tang;Q. Fu;C. Criddle;J. Leckie
中科院分区：
文献类型：
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作者：
C. Tang;Q. Fu;C. Criddle;J. Leckie
全氟辛烷磺酸（PFOS）是一种引起重大环境问题的紧急污染物。在这项研究中，反渗透（RO）和纳米过滤（NF）膜被用来从含全氟辛烷磺酸的废水中去除这种有毒的持久性化合物。在进料浓度为10 ppm PFOS的条件下，对5种反渗透膜和3种纳滤膜进行了为期4天的测试，并系统地研究了PFOS截留率和渗透通量性能。全氟辛烷磺酸截留率与氯化钠截留率密切相关。RO膜的截留率> 99%，NF膜的截留率在90- 99%之间。在较长的过滤时间下，观察到全氟辛烷磺酸截留率提高，同时通量略有下降（< 16%）。如X射线光电子能谱法、液相色谱法和串联质谱法结果所示，截留率和通量性能的这种变化可能是由于全氟辛烷磺酸在较长时间内积累增加所致。一部分PFOS分子可能被截留在复合膜的聚酰胺层中，这阻碍了水和其他PFOS分子的进一步通过。以类似的方式，全氟辛烷磺酸的排斥和结垢增强了更大的初始通量和/或施加的压力，其中全氟辛烷磺酸的积累可能是由于增加的流体动力学渗透阻力。通量减少也被证明与膜粗糙度相关，粗糙的膜往往比光滑的膜经历更多的通量减少。
Perfluorooctane sulfonate (PFOS) is an emergent contaminant of substantial environmental concerns. In this study, reverse osmosis (RO) and nanofiltration (NF) membranes were used to remove this toxic and persistent compound from PFOS-containing wastewater. Five RO membranes and three NF membranes were tested at a feed concentration of 10 ppm PFOS over 4 days, and the PFOS rejection and permeate flux performances were systematically investigated. PFOS rejection was well correlated to sodium chloride rejection. The rejection efficiencies for the RO membranes were > 99%, and those for the NF membranes ranged from 90-99%. Improvement in PFOS rejection, together with mild flux reduction (< 16%), was observed at longer filtration time. Such shifts in rejection and flux performance were probably due to the increased PFOS accumulation at longer duration, as shown by X-ray photoelectron spectroscopy and liquid chromatograph and tandem mass spectrometry results. A fraction of PFOS molecules might be entrapped in the polyamide layer of the composite membranes, which hindered the further passage of both water and other PFOS molecules. In a similar fashion, PFOS rejection and fouling were enhanced for greater initial flux and/or applied pressure, where PFOS accumulation was promoted probably due to increased hydrodynamic permeate drag. Flux reduction was also shown to correlate to membrane roughness, with the rougher membranes tend to experience more flux reduction than the smoother ones.