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首页> 外文期刊>Environmental Science & Technology >Nanofiltration for Trace Organic Contaminant Removal: Structure, Solution, and Membrane Fouling Effects on the Rejection of Perfluqrochemicals
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Nanofiltration for Trace Organic Contaminant Removal: Structure, Solution, and Membrane Fouling Effects on the Rejection of Perfluqrochemicals

机译：纳滤用于去除痕量有机污染物：结构，溶液和膜污染对全氟化学品去除的影响

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摘要

The use of nanofiltration (NF) membranes for water recycling requires an improved understanding of the factors that govern rejection of potentially harmful organic trace contaminants. Rejections of 15 perfluorochemicals (PFCs)-5 perfluorinated sulfonates, 9 perfluorinated carboxylates, and perfluorooctane sulfonamide (FOSA)-by four nanofiltration membranes (NF270, NF200, DK, and DL) were measured. Rejections for anionic species were >95% for MW > 300 g/mol. FOSA (MW = 499 g/mol), which is uncharged at the pH of deionized water (5.6), was rejected as little as 42% (DL membrane). Decreasing the pH to less than 3 decreases rejection by up to 35%, effectively increasing the MWCO of NF270 by >200 g/mol, while a 2500 mg/L NaCI equivalent increase in ionic strength reduces rejections <1%. An alginate fouling layer increases transmission, where quantifiable, by factors of 4-8. Accumulation of PFCs on membranes was measured after the completion of rejection experiments. Based on rejection kinetics and the extent of sorption, we infer that two different sorption processes are significant: charged species adsorb quickly to the membrane surface, whereas the uncharged FOSA absorbs within the membrane matrix in a much slower process.
机译：使用纳滤（NF）膜进行水循环利用，需要更好地了解控制排斥潜在有害有机痕量污染物的因素。通过四个纳滤膜（NF270，NF200，DK和DL）测量了15种全氟化学品（PFCs）-5全氟磺酸盐，9种全氟羧酸盐和全氟辛烷磺酰胺（FOSA）的排斥率。 MW> 300 g / mol时，阴离子物质的排斥率> 95％。 FOSA（MW = 499 g / mol）在去离子水（5.6）的pH值下不带电，仅42％（DL膜）被拒绝。将pH值降低到3以下可将排斥率降低35％，有效地将NF270的MWCO增加200克/摩尔以上，而当离子强度提高2500 mg / L NaCl当量时，将排斥度降低<1％。藻酸盐结垢层在可量化的情况下将透过率提高了4-8倍。完成排斥实验后，测量膜上PFC的积累。基于排斥动力学和吸附程度，我们推断出两种不同的吸附过程非常重要：带电物质迅速吸附到膜表面，而不带电荷的FOSA在膜基质中的吸收要慢得多。

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