一种新型羧甲基甲壳素/聚丙烯腈复合纳滤膜的研究

Study of a Novel Carboxymethyl Chitin(CM-CH)/Polyacrylonitrile(PAN) Composite Nanofiltration Membrane

羧甲基甲壳素（CM-CH）溶液浇铸在聚丙烯腈超滤膜上，并与环氧氯丙烷（ECH）交联制得1种新型的复合纳滤膜，研究了复合膜的制备影响因素及操作条件对膜的性能的影响，结果表明：当羧甲基甲壳素的浓度为2．096，环氧氯丙烷的浓度为2．5％，6012下交联24．0h，然后5012下热处理10min条件下制备的复合纳滤膜的截盐效果最好。表征结果表明：对聚乙二醇的截留分子量为550Da，孔径在（6．6～7．8）×10^-10m之间，离子交换容量为2．94mmol·cm^-2，静电位为-0．20mV。对1000mg·L^-1的K2SO4，Na2SO4，MgSO4，KCl，NaCl，MgCl2和CaCl2溶液的截盐率分别为93．33％，91．00％，42．61％，36．10％，44．00％，9．26％和14．21％。研究表明，复合膜对不同盐的截留行为主要决定于荷电膜与电解质离子之间静电斥力的大小。另外还发现该膜具有较好的耐藻类吸附性。

A novel composite nanofiltration membrane was fabricated by coating solution of carboxymethyl ehitin（CM-CH） onto polyacrylonitrile （PAN） UF membrane and subsequently crosslinked by epichlorohydrin （ECH）. Effects of membrane preparation conditions and operating conditions on the performance of the composite membrane were studied. The results suggested that composite NF membrane with excellent rejection performance could be prepared while the CM-CH concentration was 2.0 %, the epichlorohydrin concentration was 2.5 %, the erosslinking time was 24h at 6012, and the curing time was 10 minutes at 5012. The results of characterization showed that the cut-off molecular weight of the resulted membrane to PEG was about 550Da, the pore radii of the membrane were between （6.6-7.6） × 10^-10m, the static potential was -0.20mV, and the ion exchange capacity was 2.94 mmol·cm^-2. The salt rejections to K2SO4, Na2SO4, MgSO4, KCl, NaCl, MgCl^2 and CaCl^2 （ 1 000mg·L^-1） were 93.33 %, 91.00 %, 42.61%, 36.10 %, 44.00 %, 9.26 % and 14.21% respectively. The rejection performance of the composite membrane depended on the electrostatic strength between the charged membrane and the ions of electrolyte. This membrane also has a good property of preventing the adsorption of algae.