Compared study on separation of APAM-oil/water emulsion using two kinds of PVDF ultrafiltration membranes

Polyvinylidene fluoride (PVDF) membranes modified by nano-sized TiO2/Al2O3 were applied to the separation of APAM-oil/water emulsion. Due to the enhanced surface hydrophilicity, the modified PVDF membranes (MM) exhibited higher rejection ratio and better antifouling property compared with the control membrane (OM). There were no significant morphological variations among MM and OM, but the contact angles of OM was 83.64°, and 57.42° of MM, zeta potentials was -26.6mv and -20.2mv, separately, indicating hydrophilicity of MM was highly improved. This UF process was proved to be an effective method to treat oil emulsion, because APAM rejection ratios of all the OM and MM were higher than 97%, and oil nearly 100% under different conditions. MM still has a higher RF than OM, for its´ antifouling character and hydrophilicity improvement. There was a good flux recovery for fouled membranes when being washed with pure water, about 74% and 80% for PM and MPM respectively, and around 88% and 94% after washing with NaClO/SDS solution. However, reversed cleaning by water and mechanical scrubbing caused the pure water flux decreasing. All in all, MM showed a better antifouling characteristic than OM.