Innovative Ozone/Oxygen Reactive Flotation for Paper Deinking

To improve paper recycling, the potential of an innovative deinking process using a reactive ozone/oxygen gas mixture instead of air was studied on two recovered paper furnishes (offset print and newsprint/magazine mixture). Using suitable O₃ concentrations, ink removal, following first-order kinetics, increased and losses dropped leading to better selectivity than using air alone. The ozone benefits in term of selectivity depended on temperature and paper furnishes and reached 100% for newsprint/magazine furnish at ambient temperature. Finally deinking effluent COD was significantly reduced and the ozone-based flotation allowed the reduction of the alkaline chemistry used before flotation.