The molecular properties and carbohydrate content of lignins precipitated from black liquor
Artikel i vetenskaplig tidskrift, 2015

Precipitation and utilization of lignin from black liquor (BL) offers many promising advantages to modern kraft pulp mills. A novel process, known as “LignoBoost”, has recently been introduced as a process for separating lignin from BL; it results in lignins with a low ash and high dry solid content. There is a lack of knowledge regarding the influences of process parameters on the behavior of lignin in the precipitation step. In this study, the yield of precipitated lignin and its average molecular weight (MWt) and carbohydrate content were the focus. Nuclear magnetic resonance (NMR) analysis showed that the lignin yield increased at lower pH and temperatures or when the ion strength of BL was elevated. High yield lignins contained more low MWt components and such lignins have more phenolic OH and methoxy groups. Xylan content of the lignins decreased with decreasing pH and increasing temperature, but glucomannan content was virtually unaffected by the conditions of precipitation.

H-1 and C-13 NMR spectra of kraft lignin

lignin precipitation

molecular weight of lignin

carbohydrates analysis


black liquor


Weizhen Zhu

Chalmers, Kemi och kemiteknik, Kemiteknik, Skogsindustriell kemiteknik

Gunnar Westman

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Organisk kemi

Hans Theliander

Chalmers, Kemi och kemiteknik, Kemiteknik, Skogsindustriell kemiteknik


0018-3830 (ISSN) 1437-434X (eISSN)

Vol. 69 2 143-152


Hållbar utveckling


Fysikalisk kemi

Kemiska processer