The impact of ionic strength on the molecular weight distribution (MWD) of lignin dissolved during softwood kraft cooking in a flow-through reactor
-
Binh T.T. Dang
Abstract
The molecular weight distribution (MWD) of dissolved lignin as a function of time during kraft cooking of Scots pine (Pinus silvestris L) has been investigated, while the influence of sodium ion concentration ([Na+]) on the MWD was in focus. The kraft cooking was performed in a small scale flow-through reactor and the [Na+] was controlled by the addition of either Na2CO3 or NaCl. Fractions of black liquors (BL) were collected at different cooking times and the lignin was separated from the BL by acidification. The MWD of the dissolved lignin was analyzed by GPC. Results show that the weight average molecular weight (Mw) of dissolved lignin increases gradually as function of cooking time. An increase of [Na+] in the cooking liquor leads to Mw decrement. Findings from cooks with constant and varying [Na+] imply that the retarding effect of an increased [Na+] on delignification is related to the decrease in lignin solubility at higher [Na+].
Acknowledgments
The authors would like to thank Ms. Lena Fogelquist and Mr. Tommy Friberg for their great technical support. The financial support received from Södra Skogsägarnas stiftelse för forskning, utveckling och utbildning is gratefully acknowledged.
References
Bogren, J., Brelid, H., Theliander, H. (2008) Effect of pulping conditions on the rates of formation and degradation of hexenuronic acid in Scots pine. J. Pulp Pap. Sci. 34:23–29.Search in Google Scholar
Bogren, J., Brelid, H., Karlsson, S., Theliander, H. (2009a) Can the delignification rate be affected by previously applied cooking conditions? Nord. Pulp Pap. Res. J. 24:25–32.10.3183/npprj-2009-24-01-p025-032Search in Google Scholar
Bogren, J., Brelid, H., Bialik, M., Theliander, H. (2009b) Impact of dissolved sodium salts on kraft cooking reactions. Holzforschung 63:226–231.10.1515/HF.2009.032Search in Google Scholar
Brelid, H., Bogren, J., Dang, B., Lundqvist, F., Saltberg, A., Theliander, H. (2011) Kraft delignification: recent findings regarding the impact of non-reacting ions in the cooking liquor. Tappi PEERS, Portland, Oregon. October 2–5, 898–906.Search in Google Scholar
Brunow, G., Lundquist, K. (2010) Functional groups and bonding patterns in lignin (including the lignin-carbohydrate complexes). In: Lignin and Lignans: Advances in Chemistry. Eds. Heitner, C., Dimmel, D.R., Schmidt, J.A. CRC Press, Boca Raton, FL, USA. pp. 267–299.10.1201/EBK1574444865-c7Search in Google Scholar
Dang, B.T.T., Brelid, H., Köehnke, T., Theliander, H. (2013) Impact of ionic strength on delignification and hemicellulose removal during kraft cooking in a small-scale flow-through reactor. Nord. Pulp Pap. Res. J. 28:358–365.10.3183/npprj-2013-28-03-p358-365Search in Google Scholar
Dang, B.T.T., Brelid, H., Köhnke, T., Theliander, H. (2014) Effect of sodium ion concentration profile during softwood kraft pulping on delignification rate, xylan retention and reactions of hexenuronic acids. Nord. Pulp Pap. Res. J. 29:604–611.10.3183/npprj-2014-29-04-p604-611Search in Google Scholar
Gellerstedt, G., Lindfors, E.L. (1984) Structural changes in lignin during kraft pulping. Holzforschung 38:151–158.10.1515/hfsg.1984.38.3.151Search in Google Scholar
Gierer, J. (1980) Chemical aspects of kraft pulping. Wood Sci. Technol. 14:241–266.10.1007/BF00383453Search in Google Scholar
McNaughton, J.G., Yean, W.Q., Goring, D.A.I. (1967) Macromolecular properties of kraft lignins from spruce made soluble by a continuous flow process. Tappi 50:548–553.Search in Google Scholar
Motomura, H., Bae, S.-H., Morita, Z. (1998) Dissociation of hydroxyl groups of cellulose at low ionic strengths. Dyes Pigm. 39:243–258.10.1016/S0143-7208(98)00014-XSearch in Google Scholar
Myrvold, B.O. (2012) Salting-out and salting-in experiments with lignosulfonates (LSs). Holzforschung 67:549–557.10.1515/hf-2012-0163Search in Google Scholar
Norgren, M., Edlund, H. (2003) Ion specific differences in salt induced precipitation of kraft lignin. Nord. Pulp Pap. Res. J. 18:400–403.10.3183/npprj-2003-18-04-p400-403Search in Google Scholar
Norgren, M., Edlund, H., Wågberg, L., Lindström, B., Annergren, G. (2001) Aggregation of kraft lignin derivatives under conditions relevant to the process, Part I. Phase behavior. Colloids Surf. A 194:85–96.10.1016/S0927-7757(01)00753-1Search in Google Scholar
Norgren, M., Edlund, H., Wågberg, L., Annergren, G. (2002) Fundamental physical aspects on lignin dissolution. Nord. Pulp Pap. Res. J. 17:370–373.10.3183/npprj-2002-17-04-p370-373Search in Google Scholar
Obiaga, T.I., Wayman, M. (1973) Molecular weight distribution of lignin during alkaline pulping. Sv. Papperstidn. 76:699–703.Search in Google Scholar
Pakkanen, H., Alén, R. (2012) Molecular mass distribution of lignin from the alkaline pulping of hardwood, softwood, and wheat straw. J. Wood Chem. Technol. 32:279–293.10.1080/02773813.2012.659321Search in Google Scholar
Pu, Q., Sarkanen, K. (1991) Donnan equilibria in wood-alkali interactions. Part 2. Effect of polysaccharide ionization at high alkalinities. J. Wood Chem. Technol. 11:1–22.10.1080/02773819108050258Search in Google Scholar
Robert, D.R., Bardet, M., Gellerstedt, G., Lindfors, E.L. (1984) Structural changes in lignin during kraft cooking. Part 3. On the structure of dissolved lignins. J. Wood Chem. Technol. 4:239–263.10.1080/02773818408070647Search in Google Scholar
Sjöholm, E., Gustafsson, K., Colmsjö, A. (1999a) Size-exclusion chromatography of lignins using lithium chloride/ N,N-dimethylacetamide as mobile phase. I. Dissolved and residual birch kraft lignins. J. Liq. Chromatogr. Relat. Technol. 22:1663–1685.10.1081/JLC-100101759Search in Google Scholar
Sjöholm, E., Gustafsson, K., Colmsjö, A. (1999b) Size-exclusion chromatography of lignins using lithium chloride/ N,N-dimethylacetamide as mobile phase. II. Dissolved and residual pine kraft lignins. J. Liq. Chromatogr. Relat. Technol. 22:2837–2854.10.1081/JLC-100102063Search in Google Scholar
©2016 by De Gruyter
Articles in the same Issue
- Frontmatter
- Original Articles
- Elucidation of LCC bonding sites via γ-TTSA lignin degradation: crude milled wood lignin (MWL) from Eucalyptus globulus for enrichment of lignin xylan linkages and their HSQC-NMR characterization
- The impact of ionic strength on the molecular weight distribution (MWD) of lignin dissolved during softwood kraft cooking in a flow-through reactor
- Distinction of four Dalbergia species by FTIR, 2nd derivative IR, and 2D-IR spectroscopy of their ethanol-benzene extractives
- Content and distribution of lignans in Taiwania cryptomerioides Hayata
- Superior cellulose-protective effects of cosolvent during enhanced dissolution in imidazolium ionic liquid
- Hydrophobisation of wood surfaces by combining liquid flame spray (LFS) and plasma treatment: dynamic wetting properties
- Parametric study on the capability of three-dimensional finite element analysis (3D-FEA) of compressive behaviour of Douglas fir
- Dynamic viscoelastic properties of Chinese fir (Cunninghamia lanceolata) during moisture desorption processes
- Influence of incubation time on the vibration and mechanic properties of mycowood
- Fatigue behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP)
- Covalent fixation of boron in wood through transesterification with vinyl ester of carboxyphenylboronic acid
- Effect of fungal competition on decay rates in bicultured soil bottle assays
Articles in the same Issue
- Frontmatter
- Original Articles
- Elucidation of LCC bonding sites via γ-TTSA lignin degradation: crude milled wood lignin (MWL) from Eucalyptus globulus for enrichment of lignin xylan linkages and their HSQC-NMR characterization
- The impact of ionic strength on the molecular weight distribution (MWD) of lignin dissolved during softwood kraft cooking in a flow-through reactor
- Distinction of four Dalbergia species by FTIR, 2nd derivative IR, and 2D-IR spectroscopy of their ethanol-benzene extractives
- Content and distribution of lignans in Taiwania cryptomerioides Hayata
- Superior cellulose-protective effects of cosolvent during enhanced dissolution in imidazolium ionic liquid
- Hydrophobisation of wood surfaces by combining liquid flame spray (LFS) and plasma treatment: dynamic wetting properties
- Parametric study on the capability of three-dimensional finite element analysis (3D-FEA) of compressive behaviour of Douglas fir
- Dynamic viscoelastic properties of Chinese fir (Cunninghamia lanceolata) during moisture desorption processes
- Influence of incubation time on the vibration and mechanic properties of mycowood
- Fatigue behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP)
- Covalent fixation of boron in wood through transesterification with vinyl ester of carboxyphenylboronic acid
- Effect of fungal competition on decay rates in bicultured soil bottle assays
