Abstract
A new laboratory reactor to perform in situ studies of structural changes in wood during soda pulping using synchrotron X-ray tomography is presented. The reactor is of recirculation type to provide stable reaction conditions and mimic the industrial situation. Experiments have been performed using this reactor in situ at a synchrotron microtomography beamline to provide sequences of 3D images from which measurement of wood cell wall thickness have been possible for the first time. The results showed that the cell wall thickness increased significantly in the early stage of pulping (<10 min), which is due to the transportation of cooking chemicals through the tracheids, resin channels and pits into the cell wall, which is swollen with the increased pH. Subsequently, the cell wall thickness reduces over the processing time up to 60 min with a high rate, which is inferred to be due to the dissolution and transport of lignin and hemicellulose from the secondary walls, allowing for better transportation of active chemicals deep through the cell wall layers. After 60 min processing, the cell wall thickness reduction rate reduced, as dissolution of lignin and hemicelluloses from the cell walls ceased, while the remaining dissolution occurs mainly at the middle lamella.
Funding source: Swedish Government, European Union’s Horizon 2020
Award Identifier / Grant number: 2018-06469
Award Identifier / Grant number: 701647
Acknowledgments
The authors acknowledge the Paul Scherrer Institute, Villigen, Switzerland for provision of synchrotron radiation beamtime at the TOMCAT beamline X02DA of the SLS. Moreover, the authors acknowledge Dr. Jonas Engqvist for helping in modifying the device to be mounted over the beamline bed. Finally, the authors acknowledge Dr. Sara Johansson for her help in performing synchrotron inspection.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: The authors would like to acknowledge the ForMax pre-project initiative financed by the Swedish Government and the “FORMAX-portal - access to advanced X-ray methods for forest industry” (VR project no.: 2018-06469). V. Novak acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 701647.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Ahmed, S., Klassen, T.N., Keyes, S., Daly, M., Jones, D.L., Mavrogordato, M., Sinclair, I., and Roose, T. (2016). Imaging the interaction of roots and phosphate fertiliser granules using 4D X-ray tomography. Plant Soil 401: 125–134. https://doi.org/10.1007/s11104-015-2425-5.Search in Google Scholar
Baptista, C., Robert, D., and Duarte, A.P. (2006). Effect of pulping conditions on lignin structure from maritime pine kraft pulps. Chem. Eng. J. 121: 153–158. https://doi.org/10.1016/j.cej.2006.05.002.Search in Google Scholar
Bale, H.A., Haboub, A., MacDowell, A.A., Nasiatka, J.R., Parkinson, D.Y., Cox, B.N., Marshall, D.B., and Ritchie, R.O. (2013). Real-time quantitative imaging of failure events in materials under load at temperatures above 1600 C. Nat. Mater. 12: 40–46. https://doi.org/10.1038/nmat3497.Search in Google Scholar PubMed
Chakar, F.S. and Ragauskas, A.J. (2004). Review of current and future softwood kraft lignin process chemistry. Ind. Crop. Prod. 20: 131–141. https://doi.org/10.1016/j.indcrop.2004.04.016.Search in Google Scholar
Derome, D., Griffa, M., Koebel, M., and Carmeliet, J. (2011). Hysteretic swelling of wood at cellular scale probed by phase-contrast X-ray tomography. J. Struct. Biol. 173: 180–190. https://doi.org/10.1016/j.jsb.2010.08.011.Search in Google Scholar PubMed
Ebner, M., Marone, F., Stampanoni, M., and Wood, V. (2013). Visualization and quantification of electrochemical and mechanical degradation in Li ion batteries. Science 342: 716–720. https://doi.org/10.1126/science.1241882.Search in Google Scholar PubMed
Gellerstedt, G., Majtnerova, A., and Zhang, L. (2004). Towards a new concept of lignin condensation in kraft pulping. Initial results. C. R. Biol. 327: 817–826. https://doi.org/10.1016/j.crvi.2004.03.011.Search in Google Scholar PubMed
Gierer, J. (1980). Chemical aspects of kraft pulping. Wood Sci. Technol. 14: 241–266. https://doi.org/10.1007/bf00383453.Search in Google Scholar
Harry, K.J., Hallinan, D.T., Parkinson, D.Y., MacDowell, A.A., and Balsara, N.P. (2014). Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes. Nat. Mater. 13: 69–73. https://doi.org/10.1038/nmat3793.Search in Google Scholar PubMed
Labidi, A., Robert, D., and Pla, F. (1993). Alkaline delignification of hardwoods in a flow-through reactor working at a low residence time. Part VI. Characterization of kraft poplar lignins by 13CNMR. Holzforschung 47: 213–218. https://doi.org/10.1515/hfsg.1993.47.3.213.Search in Google Scholar
Lazarescu, C., Watanabe, K., and Avramidis, S. (2010). Density and moisture profile evolution during timber drying by CT scanning measurements. Dry. Technol. 28: 460–467. https://doi.org/10.1080/07373931003613478.Search in Google Scholar
Maire, E. and Withers, P.J. (2014). Quantitative X-ray tomography. Int. Mater. Rev. 59: 1–43. https://doi.org/10.1179/1743280413y.0000000023.Search in Google Scholar
Marone, F. and Stampanoni, M. (2012). Regridding reconstruction algorithm for real-time tomographic imaging. J. Synchrotron Radiat. 19: 1029–1037. https://doi.org/10.1107/s0909049512032864.Search in Google Scholar
Muzamal, M., Bååth, J.A., Olsson, L., and Rasmuson, A.S. (2016). Contribution of structural modification to enhanced enzymatic hydrolysis and 3-D structural analysis of steam-exploded wood using X-ray tomography. Bioresources 11: 8509–8521. https://doi.org/10.15376/biores.11.4.8509-8521.Search in Google Scholar
Paganin, D., Mayo, S.C., Gureyev, T.E., Miller, P.R., and Wilkins, S.W. (2002). Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object. J. Microsc. 206: 33–40. https://doi.org/10.1046/j.1365-2818.2002.01010.x.Search in Google Scholar PubMed
Robert, D.R., Bardet, M., Gellerstedt, G., and 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. https://doi.org/10.1080/02773818408070647.Search in Google Scholar
Santos, B.R., Hart, W.P., Jameel, H., and Chang, H. (2013). Wood based lignin reactions important to the biorefinery and pulp and paper industries. Bioresources 8: 1456–1477. https://doi.org/10.15376/biores.8.1.1456-1477.Search in Google Scholar
Scheel, M., Seemann, R., Brinkmann, M.D.M.M., Di Michiel, M., Sheppard, A., Breidenbach, B., and Herminghaus, S. (2008). Morphological clues to wet granular pile stability. Nat. Mater. 7: 189–193. https://doi.org/10.1038/nmat2117.Search in Google Scholar PubMed
Sjöström, E. (1977). The behaviour of wood polysaccharides during alkaline pulping processes. Tappi 60: 151–154.Search in Google Scholar
Tikka, P.O. and Kovasin, K.K. (1990). Displacement vs conventional batch kraft pulping – delignification patterns and pulp strength delivery. Pap. Puu 72: 773–779.Search in Google Scholar
Van den Bulcke, J., Masschaele, B., Dierick, M., Van Acker, J., Stevens, M., and Van Hoorebeke, L. (2008). Three-dimensional imaging and analysis of infested coated wood with X-ray submicron CT. Int. Biodeterior. Biodegrad. 61: 278–286. https://doi.org/10.1016/j.ibiod.2007.09.004.Search in Google Scholar
Villevieille, C., Ebner, M., Gómez‐Cámer, J.L., Marone, F., Novák, P., and Wood, V. (2015). Influence of conversion material morphology on electrochemistry studied with operando X-ray tomography and diffraction. Adv. Mater. 27: 1676–1681. https://doi.org/10.1002/adma.201403792.Search in Google Scholar PubMed
Wagih, A., Maimi, P., Blanco, N., Garcia-Rodriguez, S.M., Guillamet, G., Issac, R.P., Turon, A., and Costa, J. (2019). Improving damage resistance and load capacity of thin-ply laminates using ply clustering and small mismatch angles. Compos. Appl. Sci. Manuf. 117: 76–91. https://doi.org/10.1016/j.compositesa.2018.11.008.Search in Google Scholar
Wagih, A., Hasani, M., Hall, S.A., and Theliander, H. (2021). Micro/nano-structural evolutions in spruce wood during soda pulping. Holzforschung 75: 754–764. https://doi.org/10.1515/hf-2020-0113.Search in Google Scholar
Walker, S.M., Schwyn, D.A., Mokso, R., Wicklein, M., Müller, T., Doube, M., Stampanoni, M., Krapp, H.G., and Taylor, G.K. (2014). In vivo time-resolved microtomography reveals the mechanics of the blowfly flight motor. PLoS Biol. 12: 1–12, doi:https://doi.org/10.1371/journal.pbio.1001823.Search in Google Scholar
Walther, T. and Thoemen, H. (2009). Synchrotron X-ray microtomography and 3D image analysis of medium density fiberboard (MDF). Holzforschung 63: 581–587. https://doi.org/10.1515/hf.2009.093.Search in Google Scholar
Withers, P.J. (2007). X-ray nanotomography. Mater. Today 10: 26–34. https://doi.org/10.1016/s1369-7021(07)70305-x.Search in Google Scholar
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