Abstract：
Nanofiltration (NF) has been proven to be with great potential for the separation of morpholines with molecular weight less than 200 Da in refining reverse osmosis concentrate (ROC), but its application is significantly restricted by the membrane fouling, which can reduce the rejection and service time. To enable the long-term operation stability of nanofiltration, this work focuses on the fouling behavior of each substance in the hydrosaline organic solution on nanofiltration membrane, aiming to give insight into the fouling mechanism. To this end, in this work, the effects of salts (i.e NaCl and Na2SO4), organic substances (including N-(2-hydroxypropyl)morpholine(NMH) and 4-morpholineacetate(MHA)) and representative divalent ions (Ca2+ and Mg2+) on the performance and physicochemical properties of DK membrane were systematically investigated. The results show that both salts and organics can induce DK membrane swelling, leading to an increase of the mean effective pore size. After the filtration of Na2SO4-NaCl-H2O, the mean pore size increased by 0.002 nm, resulting in the decrease of the removal ratio of NMH and MHA for 3.82% and 13.10%, respectively. With static adsorption of NMH and MHA, the mean pore size of DK membrane increased by 0.005 and 0.003 nm. The swelling slowed the entrance of more organic molecules into membrane pores. Among them, MHA led to the terrible irreversible pore blocking. As the concentration of Ca2+ increased, gypsum scaling was formed on the membrane surface. During this process, NMH and MHA played different roles, i.e. NMH accelerated the CaSO4 crystallization while MHA inhibited. As a conclusion, the fouling behavior of substances in the high saline organic wastewater on DK membrane were systematically revealed with the fouling mechanisms proposed, which could provide an insightful guidance for membrane fouling control and cleaning in the treatment of high salinity and organic wastewater.
摘要：
纳滤（NF）已被证明在精制反渗透浓缩物（ROC）中分离分子量小于200Da的吗啉具有巨大的潜力，但其应用受到膜污染的显著限制,这可以减少拒绝和服务时间。为了使纳滤的长期稳定运行，这项工作的重点是水盐水有机溶液中的每种物质在纳滤膜上的污染行为，旨在深入了解结垢机理。为此,在这项工作中，盐的作用(i.eNaCl和Na2SO4)，系统研究了有机物质(包括N-(2-羟丙基)吗啉(NMH)和4-吗啉乙酸盐(MHA))和代表性二价离子(Ca2+和Mg2+)对DK膜性能和理化性质的影响。结果表明,盐类和有机物均能诱导DK膜溶胀,导致平均有效孔径的增加。Na2SO4-NaCl-H2O过滤后，平均孔径增加了0.002nm，导致NMH和MHA的去除率分别下降3.82%和13.10%，分别。用静态吸附NMH和MHA，DK膜的平均孔径分别增加了0.005和0.003nm。溶胀减慢了更多有机分子进入膜孔的速度。其中,MHA导致了可怕的不可逆的毛孔阻塞。随着Ca2+浓度的增加,膜表面形成石膏结垢。在这个过程中,NMH和MHA扮演不同的角色，即NMH加速CaSO4结晶,而MHA抑制。作为结论,系统地揭示了高盐有机废水中物质在DK膜上的污染行为，并提出了污染机理，为高盐度有机废水处理中膜污染的控制和清洗提供了有见地的指导。
