Investigation on TCF Bleaching of Tobacco stalk (Nicotiana tabacum L.'Coker 347') Soda Pulp

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 in 170°C for 100 minutes. Produced pulp had 37. 1 % yield and kappa number 62. Bleaching process included two stages: chelating and alkali peroxide bleaching. Results indicated that brightness increased and kappa number decreased by increasing sodium hydroxide and peroxide Hydrogen 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 all treatments. Finally، 3% caustic soda-5% peroxide treatment with initial chelating stage had the highest brightness (44. 50%) and the lowest yield (83. 20%)، was selected as the best treatment.