Identification of nanofiltration membrane foulants
Identification of nanofiltration membrane foulants
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DOI：
10.1016/j.watres.2007.05.015
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发表时间：
2007-09-01
期刊：
影响因子：
12.8
通讯作者：
Yoon, Yeomin
中科院分区：
文献类型：
--
作者：
Her, Namyuk;Amy, Gary;Yoon, Yeomin
自1999年以来，法国的Mery-sur-Oise工厂一直在使用纳滤（NF）膜（NF200）生产安全饮用水。然而，根据季节条件，偶尔也会观察到明显的污垢，即使进行了各种预处理，包括常规的地表水处理，然后进行臭氧化，加酸至pH 6.9，加抗垢剂和微过滤（6 μ m）。通过中试试验，研究了在一定操作条件下，天然有机物（NOM）特性和臭氧氧化对纳滤膜污染的影响。两个平行的试验装置分别使用砂滤水（SFW）和砂滤臭氧水（SFOW），分别在春季和秋季运行3个月。采用傅里叶变换红外光谱法、荧光激发发射矩阵法、扫描电镜法、能量色散分光光度法、hpsec - uva - doc -荧光色谱法等方法鉴定NF污染物。尽管春季样品的溶解有机碳（DOC）和紫外线（UVA）水平低于冬季样品，但这些饲料水表现出更高的污染，这可能是由于NOM的亲水性分数较高和微生物的存在。此外，在两个季节，臭氧化主要通过改变NOM特征和促进细菌细胞生长条件来增加污染程度。亲水的NOM不容易被相对亲水和带负电荷的NF200膜所排斥，因为它不带电（或带相反电荷），这表明与弹簧样品相关的NOM具有很高的污染潜力。细菌在膜上的粘附和微藻在膜上的积累可能是由于藻类在臭氧化过程中释放的胞外生物聚合物促进了微生物与膜表面的粘附。蛋白质和多糖样物质是主要的污染物。春季施用SFOW后，腐殖质对膜的轻微污染可能是由于膜表面电荷在细胞外物质污染层的基础上被随后的显著污染所屏蔽而损失。(c) 2007 Elsevier Ltd.版权所有。
The Mery-sur-Oise plant (France) has been using nanofiltration (NF) membranes (NF200) to produce safe drinking water since 1999. However, significant fouling has been occasionally observed according to seasonal conditions, even with various pre-treatments including conventional surface water treatment followed by ozonation, acid addition to pH 6.9, anti-scalant addition, and microfiltration (6 mu m). Pilot-scale filtration experiments were performed to determine the effects of natural organic matter (NOM) character and ozonation on NF membrane fouling under constant operating conditions. Two parallel pilot units were operated with sand-filtered water (SFW) and sand-filtered-ozonated water (SFOW) for 3-month periods corresponding to spring and fall seasons. To identify NF foulants, Fourier transform infrared spectroscopy, fluorescence excitation emission matrix, scanning electron microscope, energy-dispersive spectrophotometry, and HPSEC-UVA-DOC-fluorescence chromatography have been used. Even though the dissolved organic carbon (DOC) and ultraviolet (UVA) levels of spring samples were lower than those of winter season, these feed waters showed higher fouling presumably due to a higher hydrophilic fraction of NOM and the presence of microorganisms. In addition, for both seasons, ozonation increased the degree of fouling mainly by a change in NOM characteristics and by the promotion of bacterial cell growth conditions. The hydrophilic NOM is not expected to be easily rejected by the relatively hydrophilic and negatively charged NF200 membrane due to its non-charged (or oppositely charged) properties, indicating a high fouling potential by NOM associated with spring samples. The adhesion of bacteria and accumulation of microalgae on the membrane may be due to the role of extracellular biopolymers released by algae upon ozonation, promoting adhesion between microorganisms and the membrane surface. Protein- and polysaccharide-like substances were found as major foulants. The reason for the minor fouling by humic substances on membranes fed with SFOW during the spring season might be a loss of membrane surface charge due to screening by significant subsequent fouling on the base of the fouling layer of extracellular materials. (c) 2007 Elsevier Ltd. All rights reserved.