Acid Precipitation of Kraft Lignin from Aqueous Solutions: The Influence of pH, Temperature, and Xylan. (2nd January 2019)

• Record Type: Journal Article
• Authors: Sewring, Tor; Durruty, Julie; Schneider, Lynn; Schneider, Helen; Mattsson, Tuve; Theliander, Hans
• Is Part Of: Journal of wood chemistry and technology. Volume 39:Number 1(2019)
• Page Start: 1
• Page End: 13
• Publication Date: 2019-01-02
• Subjects: Acid precipitation -- kraft lignin -- particle size distribution -- xylan; Wood -- Chemistry -- Periodicals; Wood; Wood -- Chemistry; Periodicals; 674.13
• DOI: 10.1080/02773813.2018.1488870
• Languages: English
• ISSNs: 0277-3813

Abstract

Abstract : In this study, the manners in which temperature (45–77 °C) and the addition of xylan (5 g/95 g lignin) influence the onset of precipitation and evolution of the particle size distribution during acid precipitation of softwood kraft lignin were investigated in situ . No systematic trend between the onset pH of precipitation and the temperature or the addition of xylan could be observed at these conditions: the average onset pH was found to be 9.3. However, the size of the agglomerates increased as the temperature was increased, but added xylan rendered a decrease in agglomerate size. A higher onset pH was measured at increased Na ion concentration. The results indicate that the ionization degree of the phenolic groups influences the precipitation at 1 M Na ions but it is also probable that the degree of ionization of the carboxylic groups (on kraft lignin and xylan) influences precipitation (particle numbers and sizes).