Spent bleaching clay from the oil refining industry was subjected to heat regeneration in a box furnace with air. The heat reactivation was conducted without previous extraction of residual oil and with previous extraction of oil using organic solvent. The experimental temperature ranged from 723 at 873 K. A model for the kinetic of thermal reactivation of spent adsorbent has been proposed. The activation energy involved on the desorption phenomenon was determined.

In this work, a bentonite clay from Mendoza, Argentina was activated with H2SO4 (4 and 8 N) at 90ºC for 2 and 3.5 hours. Under these conditions several cations were removed from the octahedral sheet (Mg, Al, and Fe) and the DTA-TGA curves of the solids obtained after treatment were modified. Treatment time and acid concentration increased the degree of destruction of the bentonite structure. Activated samples were tested in order to verify their capacity to bleach soybean oil and were compared to a standard commercial bleaching clay. Treated samples are more efficient in bleaching than the standard.

A spent clay from the oil refining industry was recycled through an extraction process using organic solvents for removal of residual oil, followed by reactivation through heat treatment. The solvents used showed the following order in the efficiency of oil extraction: methylethylketone> acetone > petroleum ether @ hexane. The bleaching efficiency of regenerated clay samples for soybean oil was determined spectrophotometrically in the visible region. For comparison of the bleaching experiments, a sample of virgin commercial clay was used. Results showed that extraction process, using just solvent, is insufficient to recover the bleaching power of the spent clay, needing then a further high temperature treatment. The bleaching power of the regenerated clay is dependent of temperature and time of calcination. The regenerated clay samples presented a similar bleaching efficiency for soybean oil comparable to a virgin commercial clay utilized as reference.

The kinetics of the gas-phase isomerization of β-pinene over an acid-activated bentonite clay has been investigated in a fixed-bed continuous flow reactor, at atmospheric pressure between 58 and 90 oC. The major isomers produced were camphene, α-pinene and limonene. The reaction rates of β-pinene conversion and the apparent activation energy were determined. The kinetics of β-pinene isomerization was described by zero-order kinetics with an activation energy of 30-35 kJ/mol for the major products formed.