PVC/PMMA blend ultrafiltration membranes for oil-in-water emulsion separation

Polyvinylchloride (PVC)/poly(methyl methacrylate) (PMMA) blend membranes were prepared via the non-solvent-induced phase separation method to separate oil-in-water emulsion in a laboratory-scale cross-flow system. Free radical polymerization of methyl methacrylate was used to synthesize PMMA. The fabricated membranes were evaluated using a set of techniques including field emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA), atomic force microscopy, pure water flux, contact angle, and pore size distribution. The FESEM results showed that with the increase of PMMA content in the casting solution, larger macro-voids in the porous substructure have appeared, surface pores of the membranes shifted toward smaller pores, and the number of surface pores of the membranes increased. Moreover, pure water flux was increased from 157.75 L m(-2) h(-1) for pure PVC membrane to 1036.25 L m(-2) h(-1) for 0.08 wt.% PMMA blend membrane because the hydrophilicity as well as the number of pores on the surface of 0.08 wt.% PMMA was higher than that of pure PVC membrane. In addition, the results of TGA analysis revealed that the degradation temperatures shifted toward higher temperatures as the PMMA content increased. Finally, the filtration of synthetic oily wastewater was performed to evaluate membrane performances, and it was revealed that PVC/PMMA blend membranes exhibited higher turbidity removal efficiency and lower flux decline during the filtration process. This indicates that the fouling resistance properties of blend membranes improved because of the presence of PMMA and its hydrophilic effects.