Deinking of laser printed copy paper with a mediated free radical system

This work investigated the effect of a chelator-mediated bio-mimetic free radical treatment on repulping and flotation operations during the deinking of laser printed copy paper. A chelator-mediated free radical treatment was carried out at two different chemical levels and a two-step repulping method, which combined conventional alkaline repulping as well as free radical treatment, was also developed. Flotation trials were performed on each of these treated samples to separate ink particles. Results from image analysis and paper physical properties testing are presented, and the deinking efficiency for these different treatments is also compared. Results indicate that under properly controlled conditions, free radical treatment can perform better than conventional chemical deinking methods.