The Effect of Cellulase on the Physical Properties and Drainability of OCC Pulp

This research was done to evaluate of cellulase potential to improve the physical properties and drainability of OCC pulp. The OCC pulp with 10% consistency was treated enzymatically under constant conditions of temperature 50°C for 60 min and pH range of 5-5. 5 by different levels of 0. 05، 0. 1، 0. 2، 0. 3 and 0. 5% from cellulase (based on oven dry weight of waste paper). Also OCC pulps were separately pre-treated at different times of 30، 90، 120 and 150 min at given cellulase charge (0. 3%). In addition، enzyme pre-treated OCC pulps were refined mechanically at constant revolution of 2000 rpm. The results showed that without employing refining، enzymatic pre-treatment caused to improve the pulp freeness by about 22% proportional to control sample (non enzyme treated pulp with 470 ml، CSF). Using 0. 3% and 0. 5% were resulted as same as the highest freeness (600 ml، CSF). With increase in cellulase charge from 0. 05 to 0. 3%، the paper with lower calliper and higher density was resulted. Also، in unrefined OCC pulp، use of shorter duration of enzymatic treatment (30-60 min) was resulted in a pulp with higher density and air resistance. Maximum freeness (645 ml، CSF) was attained at 90 min. Increasing the enzyme level followed by refining caused to improve pulp freeness and a range of 0. 05-0. 1% cellulase is advisable as the best level of enzyme usage.