Chin.J.Chem.Eng. ›› 2013, Vol. 21 ›› Issue (5): 473-484.doi: 10.1016/S1004-9541(13)60507-8

• SEPARATION SCIENCE AND ENGINEERING • Previous Articles     Next Articles

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

WEI Xinyu1,2,3, WANG Zhi1,2,3, XU Jun1,2,3, WANG Jixiao1,2,3, WANG Shichang1,3   

  1. 1 Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    2 State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China;
    3 Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, China;
    4 Nuclear and Radiation Safety Centre, Ministry of Environmental Protection of the People's Republic of China, Beijing 100082, China
  • Received:2012-10-24 Revised:2012-12-17 Online:2013-05-28 Published:2013-05-31
  • Supported by:

    Supported by the National Natural Science Foundation of China (20676095) and the Program of Introducing Talents of Discipline to Universities (B06006).

Abstract: 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.

Key words: aromatic polyamide membrane, 1,6-hexanediol diglycidyl ether, adipoyl dichloride, hexamethylene diisocyanate ester, crosslinking, chlorine resistance