三醋酸纤维素纳米纤维膜的制备及其油水分离应用

石油开采和油船运输泄露的油污污染日益突出,使得质轻、亲水疏油的油水分离材料得到广泛关注。本文在无任何添加剂条件下,以三醋酸纤维素(TCA)/N,N-二甲基乙酰胺(DMAc)溶液通过热致相分离(TIPS)制备TCA纳米纤维膜。研究了淬火时间、温度和聚合物浓度等条件对TCA纳米纤维膜形貌的影响。TCA纳米纤维膜的形貌、孔隙率和比表面积通过SEM、乙醇法和N2吸脱附表征。实验结果表明,最佳实验条件为:淬火时间180 min、淬火温度-20℃、聚合物质量分数5%,得到直径为(110±28)nm均匀纤维膜。与块状TCA流延膜相比,TCA纳米纤维膜的高孔隙率和大比表面积以及表面特殊的微/纳结构,使其水接触角由86.2°增加到137.5°。由于高疏水性和亲油性以及强烈的毛细作用,TCA纳米纤维膜的吸油容量达到21.5 g/g,分别是流延膜的20~42倍,且可快速吸收油水混合物中的油层。TCA纳米纤维膜是一种可生物降解的溢油污染清洁材料。

Fabrication of Triacetate Cellulose Nanofiber Membranes and Their Application for Oil-Water Separation

Oil pollution caused by oil exploitation and oil carrier transportation leakage have become increasingly prominent, so lightweight, hydrophilic and oleophobic materials for oil-water separation have attracted increasing attention. In this paper, triacetate cellulose(TCA) nanofiber membranes were prepared by thermally induced phase separation method from dimethylacetamide solution without the assistance of other additives. The effects of variables such as polymer concentration, quenching temperature and time on the morphology of TCA nanofiber membranes were studied. The morphology, porosity, and specific surface area of TCA nanofiber membranes were characterized by SEM, ethanol method, and N₂ adsorption-desorption. The results show that the optimum experiment conditions are as follow: quenching time is 180 min, quenching temperature is -20 ℃, and concentration is 5% mass fraction, producing the uniform nanofiber membranes with diameters of (110±28) nm. Compared with the monolithic TCA solvent-cast film, the water contact angle of TCA nanofibers membranes increases from 86.2° to 137.5°, which is contributed to its high porosity, specific surface area and particular nano-/micro- dual scale structures. Owing to the high hydrophobicity and oleophilicity and massive capillary action, the TCA nanofiber membranes display oil absorption capacity up to 21.5 g/g. Additionally, it can absorb oil quickly in preference to water in an oil-water mixture. The TCA nanofiber membranes may find practical application as a biodegradable oil-spill cleanup material.