Lignin separation from kraft black liquor by combined ultrafiltration and precipitation: a study of solubility of lignin with different molecular properties
2016 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 2, 270-278 p.Article in journal (Refereed) PublishedText
Lignin from wood is by far the largest source of bio-based aromatic raw material. Today a vast amount of lignin is processes and incinerated in kraft pulp mills around the world. One possible option to utilize the energy surplus in a modern kraft pulp mill is to extract lignin from black liquor. Precipitation of lignin is one important step in an extraction process. This study investigates how the molecular size and functional groups of lignin influenced the precipitation yield. Cross-flow filtration was applied to fractionate lignin with different molecular weights from a black liquor, precipitation studies was made on the different fractions. The precipitated lignin was characterized by GPC, HPAEC-PAD and NMR analysis. The results show that it was possible to obtain a more homogenous lignin by fractionation using cross-flow filtration. It was found that the molecular properties of kraft lignin, i.e. molecular weight and functional groups, influenced the yield of lignin precipitation: at the same precipitation condition, lignin fraction with higher molecular weight has higher precipitation yield. Lignin fraction with lower molecular weight contains less amount of carbohydrates and methoxyl groups but higher amount of phenolic groups.
Place, publisher, year, edition, pages
2016. Vol. 31, no 2, 270-278 p.
Lignin separation, Ultrafiltration of black liquor, Lignin precipitation, NMR analysis of kraft lignin
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-190531DOI: 10.3183/NPPRJ-2016-31-02-p270-278ISI: 000378442300013ScopusID: 2-s2.0-84977534925OAI: oai:DiVA.org:kth-190531DiVA: diva2:952976
FunderChalmers Energy initiative
QC 201608162016-08-162016-08-122016-08-16Bibliographically approved