Next Article in Journal
Development of Mass Production Technology of Highly Permeable Nano-Porous Supports for Silica-Based Separation Membranes
Previous Article in Journal
Role of Cellulose Micro and Nano Crystals in Thin Film and Support Layer of Nanocomposite Membranes for Brackish Water Desalination
Open AccessArticle

Membrane Separation of the Base-Catalyzed Depolymerization of Black Liquor Retentate for Low-Molecular-Mass Compound Production

1
Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
2
Department of Chemistry, Centre for Analysis and Synthesis, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
*
Author to whom correspondence should be addressed.
Membranes 2019, 9(8), 102; https://doi.org/10.3390/membranes9080102
Received: 10 July 2019 / Revised: 5 August 2019 / Accepted: 12 August 2019 / Published: 16 August 2019
(This article belongs to the Section Membrane Engineering and Applications)
One way of valorizing the lignin waste stream from the pulp and paper industries is depolymerizing it into low-molecular-mass compounds (LMMC). However, a common problem in the depolymerization of Kraft lignin is the low yields of small aromatic molecules obtained. In the present work, the combination of the repeated depolymerization of lignin and the separation of LMMC from depolymerized lignin to upgrade them into value-added chemicals was studied. In so doing, we investigated the possibility of depolymerizing black liquor retentate (BLR). The base-catalyzed depolymerization of BLR was performed using a continuous flow reactor at 170–210 °C, with a 2 min residence time. The results obtained indicate that BLR can be depolymerized effectively under the experimental conditions. Depolymerized lignin LMMC can be successfully separated by a GR95PP membrane, and thus be protected from repolymerization. Through combining membrane filtration with base-catalyzed depolymerization, more than half of the lignin could be depolymerized into LMMC. Around 46 mg/g of lignin monomers (guaiacol, vanillin, acetovanillone, and acetosyringone), which can potentially be upgraded to high-valued chemicals, were produced. On the basis of our results, we suggest use of a recycling Kraft lignin depolymerization and filtration process for maximizing the production of LMMC under mild alkaline conditions. View Full-Text
Keywords: Kraft lignin; depolymerization; membrane filtration; low-molecular-mass compounds Kraft lignin; depolymerization; membrane filtration; low-molecular-mass compounds
Show Figures

Graphical abstract

MDPI and ACS Style

Li, K.; Al-Rudainy, B.; Sun, M.; Wallberg, O.; Hulteberg, C.; Tunå, P. Membrane Separation of the Base-Catalyzed Depolymerization of Black Liquor Retentate for Low-Molecular-Mass Compound Production. Membranes 2019, 9, 102.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop