Environmentally Safe Oxidants for Degradation of Organic Pollutants

Ahmad Al-Ajlouni
Jordan University of Science and Technology

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     Last modified: January 28, 2006

Abstract
Oxidation is very important process in many fields of chemistry and chemical industries. The most important element in the oxidation reactions is the oxidant. There are many oxidants, such as permanganate, chromate, chlorine, chlorine oxides, ozone, and peracids, that have been widely used to carry out these oxidation processes. Most of these reagents are powerful oxidants. However, due to environmental concerns, most of these oxidants are not accepted. Molecular oxygen and hydrogen peroxide are perfect oxidants due to many reasons: 1) They are cheep and available, 2) Their byproduct from the oxidation reaction is water, 3) They are environmentally safe and well accepted, 4) Their the oxygen content is high; in O2, the %O available for transfer is 100% and in H2O2 is about 50%, and 5) Hydrogen peroxide is highly soluble in water and in all polar organic solvents. In nonpolar solvents, the solubility can be enhanced greatly by adding a transfering agent, such as surfactants.
In this work, we have studied the catalytic activation of H2O2 by polyoxometals of Mo and W, such as H3PMo12O40, Na5Mo10V2PO40 and PhPW3O19H2-3, toward oxidation of phenols under homogeneous conditions. In most cases the oxidation leads to complete destruction of the phenol to acetic acid, carbon dioxide and water. Detailed kinetic studies were carried out in order to investigate the reaction mechanism, and to find out the best conditions and improve the catalysts’ activities.