Deinking of colored offset newsprint with enzyme treatment in cooperation with ultrasonic wave

摘要

A new process for deinking of colored offset newsprint, i.e. enzyme treatent in cooperation with ultrasonic wave, was developed in the present study. It was found out that colored offset newsprint could be deinked effectively by cellulase treatment, when an ultrasonic wave was applied. Brightness increased by 5% ISO over that of control experiment. Morevoer, the pigment content was reduced markedly, and the ink particles on the surface of fibre obviously decreased. The physical characteristics, such as fiber length, coarseness, crystallinity index of the deinked pulps, were investigated, and the sugar residues released from the treatment were analyzed, as well. Although the ultrasonic wave had little effect on the strength and crystallinity of the pulp, the treatment of enzyme, combined with the ultrasonic wave, reduced the coarseness and fibre length to some extent. It was also found out that the ultrasonic wave could increase the activity of cellulase and therefore accelerte the hydrolysis of cellulose and hemicellulose during the enzymatic treatment of newsprint. These results could very well explain the effect of the ultrasonic wave on the enzymatic deinking process.