芳香聚酰胺纳滤膜在电解质溶液中的动电现象

研究芳香聚酰胺纳滤膜在不同电解质溶液中的流动电位,考察膜两侧压差、电解质浓度、离子价态及溶液pH值对流动电位的影响,用Helmoltz-Schmolukovski方程与Gouy-Chapmann方程计算膜表面的Zeta电位与电荷密度。结果表明:芳香聚酰胺膜表面荷负电荷;流动电位和Zeta电位绝对值均随电解质浓度的增大而减小;溶液pH值对流动电位和Zeta电位的影响较大;当电解质溶液浓度相同时,芳香聚酰胺膜的流动电位和Zeta电位的绝对值在二价阳离子电解质溶液中比一价阳离子的电解质溶液中均要小,但前者中的等电位点的pH值略大。

对芳香聚酰胺海水反渗透复合膜元件高压测试系统的修正

以简便实用的公式 ,介绍了芳香聚酰胺海水反渗透复合膜元件在非标准条件下的膜指标Fa(T ,Cf,p ,Y)与标准测试条件下的膜指标Fs(2 5℃ ,32 0 0 0mg/L ,5 5 0 0kPa ,8% )

芳香聚酰胺反渗透复合膜的抗氧化性能研究

研究次氯酸钠、双氧水、过氧乙酸等氧化剂对芳香聚酰胺反渗透膜性能的影响。通过膜表面接触角、膜通量、截留率以及表面化学结构等表征,重点考察了pH、氧化剂浓度以及处理时间对膜的分离性能和化学结构的影响。结果表明,芳香聚酰胺反渗透膜对过氧乙酸和双氧水具有较好的抗氧化性能,其对次氯酸钠的抗氧化性能与pH、次氯酸钠浓度、处理时间等有关。为芳香聚酰胺反渗透膜的有机生物污染处理工艺的选择提供理论和试验依据。

Surface Modification of Commercial Aromatic Polyamide Reverse Osmosis Membranes by Crosslinking Treatments

Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.

反渗透膜的研究进展与展望

反渗透具有低能耗、高效率等突出优点,是目前应用最为广泛的分离技术之一。反渗透膜的性能是影响反渗透过程效率的决定因素,反渗透膜的研制一直是国内外膜领域的研究热点。特别是近年来,石墨烯、碳纳米管等新型材料展现出优异的水传递行为,成为新型反渗透膜材料的研究热点。本论文回顾了反渗透膜的研制发展历程,介绍了不同单体通过界面聚合反应成膜的研究进展,综述了国内外新型混合基质膜和无机分子筛反渗透膜材料及其成膜研究,最后提出了新型反渗透膜的研究方向。