Oil/water separation using a lauric acid-modified, superhydrophobic cellulose composite membrane

To achieve cheap and highly efficient separation of oil/water mixtures, a superhydrophobic ployvinylidene fluoride (PVDF) and microcrystalline cellulose (MCC) composite membrane was prepared by a two-step method, in which MCC and PVDF were directly mixed to form the membrane at 25 °C, then lauric acid was induced on surface of the membrane using grafting method. Then membranes were characterized using field emission scanning electron microscope (SEM) Attenuated total reflection infrared spectra (FTIR-ATR). Thermogravimetric analysis (TGA), water contact angle (WCA). The water contact angle of the superhydrophobic membrane in air is 153° ± 2° and the separation efficiency for different immiscible oil/water mixtures is above 99%. The superhydrophobic membrane (119.6 mg/g loading amount of lauric acid) has a high flux of 8800 L m−2 h−1 for n-hexane-water mixture and stable separation performance to kerosene-water mixture, which can be reused 20 times without decreasing the separation efficiency. Meanwhile, surfactant-stabilized emulsions can be effectively separated using the superhydrophobic membrane under gravity. Besides, the superhydrophobic film can be degraded in soil.