Abstract
Study was conducted to improve the quality of used edible oils by membrane processing, so as to make recycling feasible. Membrane experiments were conducted on used edible oil in a flat membrane batch cell using polytetrafluoroethylene microfiltration, polymeric nanofiltration, and nonporous hydrophobic polyimid composite (NTGS-2200) membranes. For comparison, used edible oil was also improved using activated carbon.
Nanofiltration and activated carbon processing improved the color of used edible oil slightly, but did not reduce viscosity. Microfiltration failed to improve either color or viscosity of used edible oil. Color and viscosity of used edible oil were improved to the extent of fresh oil, and polar compounds and oxidation products of used edible oil were reduced by 70% and 38% respectively using the NTGS-2200 membrane. Oil stability of NTGS-2200 membrane processed oil showed no improvement over that of used edible oil. POV was found closely correlated to the viscosity of used, fresh and NTGS-2200 membrane processed oils during the same processing in the AOM test.
