Stepwise hot water and alkali extraction of birch sawdust to produce xylan and cellulose

Marjatta Kleen, Marjo Määttänen, Sari Asikainen, Tiina Liitiä, Mia Tehomaa

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

4 Citations (Scopus)

Abstract

In order to dissolve xylan with high yield, but also to preserve the average molar mass of the dissolved xylan as high as possible, stepwise pressurized hot water extraction (HWE) followed by alkali extraction was applied to industrial birch sawdust in a semi-pilot scale apparatus. This process revealed that the hot water extraction at 160°C for 2 h was the most effective step to dissolve xylan. The total extraction process dissolved 99% of the native xylan. HWE at 160°C for 30 min released material with the highest weight average molar mass (Mw 12-14 kDa), and consisting mainly of xylan. The extraction residue, containing mainly cellulose (76%) and lignin (21%), was delignified and bleached to remove the residual lignin and to produce hemicellulose-and lignin-free cellulose. After soda pulping and oxygen and chlorine dioxide bleaching, the pulp had kappa number 0.85 and ISO-brightness 79.8%. The cooking and bleaching process should be further optimized. (10 refs.)
Original languageEnglish
Title of host publicationProceedings
Subtitle of host publication16th International Symposium on Wood, Fiber and Pulping Chemistry, 16th ISWFPC
Pages666-671
Volume1
Publication statusPublished - 2011
MoE publication typeA4 Article in a conference publication
Event16th International Symposium on Wood, Fiber and Pulping Chemistry, 16th ISWFPC - Tianjin, China
Duration: 8 Jun 201110 Jun 2011

Conference

Conference16th International Symposium on Wood, Fiber and Pulping Chemistry, 16th ISWFPC
Abbreviated title16th ISWFPC
CountryChina
CityTianjin
Period8/06/1110/06/11

Keywords

  • alkali extraction
  • betula verrucosa
  • bleaching
  • birch sawdust
  • cellulose
  • hot water extraction
  • lignin
  • molar mass
  • pressurized extraction
  • pulping
  • xylan

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  • Cite this

    Kleen, M., Määttänen, M., Asikainen, S., Liitiä, T., & Tehomaa, M. (2011). Stepwise hot water and alkali extraction of birch sawdust to produce xylan and cellulose. In Proceedings: 16th International Symposium on Wood, Fiber and Pulping Chemistry, 16th ISWFPC (Vol. 1, pp. 666-671)