Abstract:

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.

Key words: thermally induced phase separation, triacetate cellulose, nanofibers, oil water separation