Evaluation of the pulp properties produced from rice straw by monoethanolamine and potassium sulfite combined processes

Document Type : Research Paper

Authors

1 Graduated M.Sc., Gorgan university of agricultural sciences and natural resources, Iran

2 Associate Prof., Department of wood and paper science & technology, Faculty of natural resources, University of Tehran, Karaj, Iran

3 Assistance Prof, Department of wood and paper science and technology, University of Mohaghegh Ardabili, Iran

Abstract

In this research, momoethanolamine in the charge of 15% with potassium sulfite in four levels as additive and also potassium sulfite in the charge of 14 % as NaOH with addition of monoethanlolamine in four levels were used as cooking liquor for pulping of rice straw. The combination of potassium sulfite/potassium hydroxide and sodium sulfite/sodium hydroxide in the ratio of 50/50 and sulfite sodium treatment in the alkalinity of 14 % as NaOH were selected as reference treatments. The results showed that the pulp produced using pure monoethanolamine (15%) has the highest yield and the highest kappa number. By using potassium Sulfite as an additive in MEA pulping, the rejects, yield and kappa number was decreased and the lowest yield and the lowest kappa number was relevant to monoethanolamine(15%) combined with potassium sulfite (40%). In potassium sulfite (14%) pulping with increasing of monoethanolamine concentration as additive, the amount of total yield increased but the kappa number and reject contents decreased. The highest tensile index was relevant to monorthanolamine (15%) combined with potassium sulfite (10%) and the highest burs index belongs to potassium sulfite (14%) / monoethanolamine (20%) treatment. According to the optical properties, it was found that the highest brightness) achieved in potassium sulfite (14%) / monoethanolamine (20%). The highest opacity was relevant to the monoethanolamine 15% treatment. The results of this study showed that monoethanolamine process in combined with potassium sulfite can be performed successfully on rice straw and pulp properties especially mechanical characteristics in combination case are superior to soda and potassium hydroxide processes. Furthermore, utilization of the combined processes for the pulping of rice straw could be provided the possibility of the use of cooking liquor as organic fertilizers, which its recovery seems to be challenging.

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