Enzymatic Deinking of Old Newspaper with Cellulase and Lipase

Biotechnical methods have the potential to offer significant improvements for traditional pulp and paper manufacturing processes due to their specificity and possible environmental advantages. Current deinking processes use large amounts of expensive, potentially environmentally damaging chemical which makes the method expensive and highly environmentally damaging. The use of enzymes could be an attractive alternative to chemicals in deinking. This research was carried out to study the influence of enzymatic deinking on optical properties and mechanical strengths of old newspaper deinked pulps. In order to perform this research, we did pulping operation with cellulase and lipase enzyme, in 4% consistency for 2.5 minutes in neutral PH, in two temperatures of 20 °C and 50 °C. After we made the pulps, we started deinking process by washing on the sieve having 120 meshes. Following this, we did statistical analyses the effect of enzymatic andtemperature treatment on optical properties and mechanical strengths of shandsheets. Results got from measuring optical properties showed that enzymatic deinking of papers leads to brightness promotion and reduces the dirt count and dirt area of handsheets. The highest brightness level and lowest dirt count and dirt area were observed in repaired samples having cellulase in 50 °C. For handsheets made from control pulp the values of folding endurance, TEA, elongation, brightness, dirt count and dirt area were 3, 34.625 J/m2, 1.74 %, 42.46 %, 51 and 1.008 mm2, respectively. On the contrary, for enzyme treated pulps the optimum values of folding endurance, TEA, elongation, brightness, dirt count and dirt area were 4, 51.54 J/m2, 2.03 %, 43.91 %, 15 and 0.245 mm2, respectively. This investigation showed that enzymatic deinking can be a suitable alternative instead of current deinking in paper recycling industries.