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

Preparation of Nanofiltration Membrane Based on Cross-linked Modification of Regenerated Cellulose and Its Study on Inorganic Salt Retention Performance

关键词:  纤维素再生膜  纤维素复合纳滤膜  海藻酸钠  羧甲基纤维素  环氧氯丙烷

Key Words:cellulose regenerated membrane  nanofiltration membrane  sodium alginate  carboxymethyl cellulose  epichlorohydrin

摘要: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、Na₂SO₄、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4.7 mm，伸长率9.40%，抗张强度5.554 kN/m，机械性能相对提高。

Abstract: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， MgCl₂， 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 epichlorohydrin was 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 nanofiltration membrane elongation was 4.7 mm， the rate of elongation was 9.40%， indicating its mechanical performance increased compared with BCM．