Heterogeneously catalyzed lignin depolymerisation in continuous flow : Assessing feedstock pretreatment and catalyst deactivation
De Saegher, Tibo LU ; Elmroth Nordlander, Jonas LU ; Hallböök, Filip LU ; Atanasova, Boyana ; Vermeir, Pieter ; Van Geem, Kevin M. ; De Clercq, Jeriffa ; Verberckmoes, An ; Hulteberg, Christian LU
and Lauwaert, Jeroen
(2025)
In Chemical Engineering Journal
503.
- Abstract
Due to the large-scale production of lignin, continuous flow reactors are preferred for its further valorization through depolymerization. However, there is limited literature on their use in lignin depolymerization, especially concerning feedstock pretreatments and catalyst deactivation. Therefore, in this study, the impact of a batch solvolysis pretreatment on the mild reductive catalytic depolymerization of Soda lignin, with and without a Pd catalyst, is evaluated and catalyst deactivation is systematically assessed. The Pd catalyst substantially enhances Mw reductions, e.g., without feedstock pretreatment, it increases the Mw reduction from approximately 70 % to 90 % at low time-on-streams (T.O.S.). It also... (More)
Due to the large-scale production of lignin, continuous flow reactors are preferred for its further valorization through depolymerization. However, there is limited literature on their use in lignin depolymerization, especially concerning feedstock pretreatments and catalyst deactivation. Therefore, in this study, the impact of a batch solvolysis pretreatment on the mild reductive catalytic depolymerization of Soda lignin, with and without a Pd catalyst, is evaluated and catalyst deactivation is systematically assessed. The Pd catalyst substantially enhances Mw reductions, e.g., without feedstock pretreatment, it increases the Mw reduction from approximately 70 % to 90 % at low time-on-streams (T.O.S.). It also yields products with more functionalities from the untreated feedstock, i.e., at low T.O.S., the phenolic and aliphatic OH content increases from 4.21 to 4.89 mmol/g and 2.30 to 3.72 mmol/g, respectively. The differences are less pronounced with the pretreated feedstock due to condensation of the lignin structure. Furthermore, the high space–time that can be achieved at a short residence time negates the need for a pretreatment. Regarding deactivation, no significant Pd leaching or poisoning by S or Na was observed. The Pd nanoparticles grew from about 8 nm to 20 nm (pretreated feed) and 17 nm (untreated feed), which is likely due to the phase change from PdO to metallic Pd rather than deactivation through sintering. The support material changed from γ-Al2O3 to boehmite, leading to the loss of acid sites and morphological changes. While some indications for small amounts of coke deposits were observed, they could not be differentiated from interstitial water within the boehmite structure. Thus, the main cause for deactivation of the Pd catalyst was identified to be the hydrothermal instability of the alumina support.
(Less)
- author
- De Saegher, Tibo
LU
; Elmroth Nordlander, Jonas
LU
; Hallböök, Filip
LU
; Atanasova, Boyana
; Vermeir, Pieter
; Van Geem, Kevin M.
; De Clercq, Jeriffa
; Verberckmoes, An
; Hulteberg, Christian
LU
and Lauwaert, Jeroen
- organization
- publishing date
- 2025-01-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Bio-aromatics, Catalyst deactivation, Continuous flow reactor, Depolymerization, Feedstock pretreatment, Heterogeneous catalysis, Lignin
- in
- Chemical Engineering Journal
- volume
- 503
- article number
- 158216
- pages
- 13 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:85211068538
- ISSN
- 1385-8947
- DOI
- 10.1016/j.cej.2024.158216
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2024 Elsevier B.V.
- id
- b4d0bb93-70c9-4eca-8e9f-8165f5fe5a7f
- date added to LUP
- 2025-02-26 14:37:55
- date last changed
- 2025-03-04 10:31:20
@article{b4d0bb93-70c9-4eca-8e9f-8165f5fe5a7f,
abstract = {{<p>Due to the large-scale production of lignin, continuous flow reactors are preferred for its further valorization through depolymerization. However, there is limited literature on their use in lignin depolymerization, especially concerning feedstock pretreatments and catalyst deactivation. Therefore, in this study, the impact of a batch solvolysis pretreatment on the mild reductive catalytic depolymerization of Soda lignin, with and without a Pd catalyst, is evaluated and catalyst deactivation is systematically assessed. The Pd catalyst substantially enhances M<sub>w</sub> reductions, e.g., without feedstock pretreatment, it increases the M<sub>w</sub> reduction from approximately 70 % to 90 % at low time-on-streams (T.O.S.). It also yields products with more functionalities from the untreated feedstock, i.e., at low T.O.S., the phenolic and aliphatic OH content increases from 4.21 to 4.89 mmol/g and 2.30 to 3.72 mmol/g, respectively. The differences are less pronounced with the pretreated feedstock due to condensation of the lignin structure. Furthermore, the high space–time that can be achieved at a short residence time negates the need for a pretreatment. Regarding deactivation, no significant Pd leaching or poisoning by S or Na was observed. The Pd nanoparticles grew from about 8 nm to 20 nm (pretreated feed) and 17 nm (untreated feed), which is likely due to the phase change from PdO to metallic Pd rather than deactivation through sintering. The support material changed from γ-Al<sub>2</sub>O<sub>3</sub> to boehmite, leading to the loss of acid sites and morphological changes. While some indications for small amounts of coke deposits were observed, they could not be differentiated from interstitial water within the boehmite structure. Thus, the main cause for deactivation of the Pd catalyst was identified to be the hydrothermal instability of the alumina support.</p>}},
author = {{De Saegher, Tibo and Elmroth Nordlander, Jonas and Hallböök, Filip and Atanasova, Boyana and Vermeir, Pieter and Van Geem, Kevin M. and De Clercq, Jeriffa and Verberckmoes, An and Hulteberg, Christian and Lauwaert, Jeroen}},
issn = {{1385-8947}},
keywords = {{Bio-aromatics; Catalyst deactivation; Continuous flow reactor; Depolymerization; Feedstock pretreatment; Heterogeneous catalysis; Lignin}},
language = {{eng}},
month = {{01}},
publisher = {{Elsevier}},
series = {{Chemical Engineering Journal}},
title = {{Heterogeneously catalyzed lignin depolymerisation in continuous flow : Assessing feedstock pretreatment and catalyst deactivation}},
url = {{http://dx.doi.org/10.1016/j.cej.2024.158216}},
doi = {{10.1016/j.cej.2024.158216}},
volume = {{503}},
year = {{2025}},
}