Influence of the physical-chemistry properties of an acid-activated bentonite in the bleaching of olive oil

The bleaching process at 90°C of an olive oil from Jaen (Spain) using natural bentonite and bentonite acid treated with H2SO4 (over a concentration range between 0.50 M and 5.00 M) has been studied. The bleaching capacities of the bentonite samples were calculated by applying the Freundlich equation to the experimental data points corresponding to the bleaching process. The bleaching capacities (KF parameter) range from 2.5 × 10−7 for non-treated bentonite up to 0.85 for 2.50 M H2SO4 treated bentonite. The bleaching capacity of the 5.00 M H2SO4 treated bentonite (KF = 0.81) is less than that of the 2.50 M H2SO4 treated bentonite.