WET OXIDATION OF NON-WATER-SOLUBLE POLYMERS

Wet oxidation is beginning to be used world-wide to treat organic liquid municipal and industrial wastes. As the degradation of plastics is an environmental concern, the objective of this study is to determine the ability of wet oxidation to oxidize solid wastes such as polystyrene or polyethylene. Oxidation efficiency is found to depend on temperature, residence time and to a lesser extent on the initial oxygen pressure. A COD reduction close to 100% is obtained after four hours of reaction at 320-degrees-C or after one hour at 280-degrees-C with a catalyst. During degradation, there is formation of a refractory intermediate: acetic acid, which limits the oxidation rate. Its concentration could be reduced by raising the temperature or by using a catalyst which inhibits its production.