Kinetics of adsorption of free fatty acids from water-degummed and alkali-refined soy oil using regenerated clay

The adsorption kinetics of residual free fatty acids (FFA) from water-degummed and alkali-refined soy oil with regenerated clay was investigated by determining the concentration change of FFA in the oils before and after adsorption. Experimental results indicated that FFA concentration was reduced as adsorption proceeded, reached a minimum at fifteen min and then increased as time increased further. The initial adsorption rate was found to increase upon increasing the initial FFA concentration, the ratio of clay/oil or agitation speed. The rate could also be increased upon decreasing the particle size or adsorption pressure. The effects of water content of clay and temperature on the initial adsorption rate, however, were found to be mild. Furthermore, the empirical rate expression for the adsorption of FFA has been determined.