Bleaching of Tobacco stalk (Nicotiana tabacum L.’PVH 19') soda pulp with alkaline peroxide

 In this study, the effect of different values of peroxide in three levels 3%, 4%, 5% and sodium hydroxide in two levels 2%, 3%, on bleaching of tobacco stalks (Nicotiana tabacum L.’PVH 19') soda pulp was investigated. Tobacco stalks were soda pulped using 22% alkali at 170°C for 100 min. Produced pulp had 36.2% yield and kappa number of 77. Bleaching process was included two stages of chelating and alkali peroxide bleaching. Results indicated that brightness increased and kappa number decreased by increasing sodium hydroxide and hydrogen peroxide level. The data related to 3% caustic soda and 5% peroxide treatment without chelating stage indicated that initial chelating stage significantly affected on the brightness, kappa number and yield of the bleached pulp, and this treatment had the lowest brightness and the highest kappa number and yield among the treatments. Finally, 3% caustic soda-5% peroxide treatment with initial chelating stage had the highest brightness (40.99%) and the lowest yield (40.10%), was selected as the best treatment.