enzymatic deinking of office waste papers in the comparison with conventional chemical method: part 1- appearance and optical properties of pulp

mixed office waste papers are considered as a large source of high quality papers that were printed with non impact printing methods. this papers have involved and economical problem in deinking with conventional chemical methods. in this research enzymatic deinking was done as an alternative for conventional chemical method. enzymatic deinking of xerox machine printed papers with cellulase from aspergillus niger at three different dosages of 0.025, 0.05 and 0.1 percent on od pulp (25, 50 and 100 iu), and repulping treatment times of 10 and 15 minutes at 50 °c were carried out and the effects of this treatmens on appearance and optical properties of handsheets were studied. the results were shown that treatment with 0.05 percent enzyme at 15 minute was better than other enzymatic treatments and caused improvement in appearance properties of handsheets compared with control (without any chemical or enzyme).