均质纤维素膜的制备及其正渗透性能研究

以纤维素(cellulose)为膜材料,离子液体1-乙基-3甲基咪唑醋酸盐(EMIMAc)为溶剂,水为非溶剂,无纺布作为支撑层,通过相转化法制备了纤维素均质膜。采用红外、X-射线衍射和扫描电子显微镜表征了膜的结构及形貌,考察了该膜的正渗透性能。结果表明:纤维素溶解再生过程中没有发生化学变化,但晶型发生了转变;当原料液为0.6 mol/L的氯化钠水溶液,汲取液为特制的营养液时,所制备的正渗透膜的水通量为3.534 L/(m2·h),截盐率达到99%以上。

Preparation and performance of homogeneous cellulose forward osmosis membrane

The nonporous homogeneous cellulose membrane for forward osmosis was prepared via phase inversion method using ionic liquid 1-ethyl-3-methyl-imidazolium acetate (EMIMAc) as solvent, water as nonsolvent on a non-woven fabric substrate. The characterizations of Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopies showed that no obvious change occurred in the chemical structure of cellulose after membrane formation, but the crystallinity had a certain degree of decline. The cross-section and the surface morphologies of the cellulose forward osmosis membrane were analyzed by scanning electron microscopy (SEM). The membrane performance were investigated by measuring water flux and rejection of simulated seawater. The water flux of the cellulose forward osmosis membrane, which the cellulose concentration is 8 %(wt) in casting solution, was 3.534 L/m₂.h and the rejection for NaCl was more than 99 %, using 0.6 mol/L NaCl solution as the feed solution and lab-made nutrient solution as the draw solution.