抄録
The utilization of waste paper becomes important issue from the environmental point of view. But there are several technical problems to extend it, such as high COD loadin the effluent, sticky contaminants, and low productivity at paper machine. These problems would be due to a conventional alkaline deinking process. Although the utilization of an enzyme into deinking process has been reported to solve some of these problems, an enzyme can not be used for deinking because of its cost. In order to improve the cost performance and apply it into an actual process, first of all we have studied the deinking mechanism of toner printed paper by the enzyme. Several treatment enzymatic deinking trials have been done under the different condition of the enzyme dosage and mechanical force.
The treatment with a strong force could separate ink at the floatation efficiently. It could be due to the enzymatic action to separate fibers and the toner. We observed two types of hairy toner, surface hairy toner which stuck fibers on its surface, and internal hairy toner which contained fibers inside. By this treatment only surface hairy toner was modified into clean toner. However the enzymatic treatment without mechanical force could not change the form of the toner, and decreased the efficiency to separate ink at the floatation. We observed the similar result when a higher charge of the enzyme and the strong mechanical force were used. When toner size and the fiber characteristics were checked to see the reason of this phenomenon, the size was not changed, but most of fibrils on the surface of fibers and fines in slury were disappeared. It would be concluded that the floatation of the hairy toner could be difficult because of the enzymatic removal of fibrils on fibers and fines and of the less physical contact between the toner and the bubbles.
