再生纤维素基交联改性纳滤膜的制备及对无机盐截留性能的研究

摘要

The regenerated bamboo cellulose membrane(BCM) was used as base film,sodium alginate(ALG) and carboxymethyl cellulose (CMC) were applied as the active layer coating solution,and the epichlorohydrin(ECH) was used as cross-linking agent to prepare a bamboo cellulose based nanofiltration membrane(CL-NF-BCM) by cross-linking methodin the study.The membrane preparation process and the retention performances of different salts,such as NaCl,Na2SO4,MgCl,MgSO4 and CaCl2 (500 ppm) were investigated.The results showed that the water flux of the CL-NF-BCM was 13.75 L/(m2 · h) and the NaCl retention rate was 48.15％ when the concentration of the mixed coating solution of sodium alginate and carboxymethyl cellulose (mix ratio =1 ∶ 3) was 2.0％,and the concentration of epichlorohydrinwas 3.0％.The water flux of BCM was 487.81 L/(m2 · h),which was significantly higher than CL-NF-BCM,while the rejection of the salt in CL-NF-BCM was significantly higher than BCM,i.e.1.52％.The retention order of the salts was:Na2SO4 ＞ MgSO4 ＞ NaCl ＞ MgCl2 ＞ CaCl2.The tensile strength of the cellulose membrane was 46.65 N,the tensile strength of the cross-linked nanofiltration membrane was 83.31 N,increased 44.0％,and the cross-linked composite nanofiilration membrane elongation was 4.7 mm,the rate of elongation was 9.40％,indicating its mechanical performance increased compared with BCM.%以竹纤维素再生膜为基膜,海藻酸钠和羧甲基纤维素的共混溶液为涂覆液,环氧氯丙烷为交联剂,采用交联法制备了一种新型纤维素复合纳滤膜.研究了纳滤膜的制备工艺和对NaCl、Na2 SO4、MgCl2、MgSO4、CaCl2(500 mg/L)的截留性能.结果表明,在海藻酸钠与羧甲基纤维素共混溶液质量分数2.0％、共混比1∶3、环氧氯丙烷质量分数3.0％条件下,纤维素复合纳滤膜的膜通量为13.75 L/(m2 ·h),NaCl截留率为48.15％,较纤维素再生膜的膜通量(487.81 L/(m2 ·h))下降明显,较纤维素再生膜的截留率(1.52％)有明显提高.对几种无机盐的截留性能顺序为:Na2SO4＞MgSO4＞NaCl＞MgCl2＞CaCl2.相比纤维素再生膜,纤维素复合纳滤膜的抗张力为83.31 N,比纤维素再生膜的抗张力(46.65 N)提高了44.0％,膜伸长量4.7mm,伸长率9.40％,抗张强度5.554 kN/m,机械性能相对提高.