纤维素非对称中空纤维超滤膜的制备与油水分离应用的研究

Preparation of Cellulose Hollow Fiber Asymmetric Ultrafiltration Membrane and Its Application to Oil-Water Separation

以N,N-二甲基乙酰胺为非溶剂添加剂制备了纤维素非对称中空纤维超滤膜,同时考察了外凝胶浴温度以及芯液种类对纤维素非对称中空纤维超滤膜结构和性能的影响,并制备了大尺寸膜组件进行油水分离实验。实验结果表明,非溶剂添加剂的加入提高了纤维素中空纤维超滤膜的渗透通量;且随外凝胶浴温度的升高,膜断面出现更多的指状孔结构,外皮层厚度逐渐减小,渗透通量增大,在外凝胶浴温度为65℃时达到29.3L/(m2.h1);采用二甲基亚砜为芯液,膜内侧皮层消失,外皮层变薄,得到含有大量贯通状孔的更明显的非对称结构;油水分离实验中,在不同油质量浓度的原料液条件下,膜组件对油的截留率均可达到98%以上;并对油质量浓度50mg/L的原料液进行了540h操作考察,渗透液含油量小于1mg/L。

Cellulose hollow fiber asymmetric ultrafiltration membrane was prepared using dimethylacetamide as the non-solvent additive. Effects of the different coagulation temperatures and internal coagulants on both the structure and properties of the membrane were investigated. Permeation flux increased with addition of non-solvent additive. With heightening of coagulation temperature from 0 ℃ to 65 ℃, many finger-like macropores were found and thickness of the outer skin decreased. Membrane permeation flux increased with rise of coagulation temperature and reached 29.3 L/ （m2 · h） at 65 ℃. Many asymmetric structures with a lot of finger-like macropores were obtained when dimethylsulphoxide was used as interna/ coagulant. Cellulose membrane module was prepared and used in oil-water separation. Rejection rate of oil were higher than 98% at all tested feed concentration. Stability experiment was carried out for 540 h under the condition of oil mass concentration 50 mg/L in feed and mass concentration of oil in permeate was below 1 mg/L.