Scholarly Work - Chemical & Biological Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8718
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Item Scale-Up of a Two-Stage Cu-Catalyzed Alkaline-Oxidative Pretreatment of Hybrid Poplar(American Chemical Society, 2024-03) Dülger, Dilara N.; Yuan, Zhaoyang; Singh, Sandip K.; Omolabake, Surajudeen; Czarnecki, Celeste R.; Nikafshar, Saeid; Li, Mingfei; Bécsy-Jakab, Villő E.; Park, Seonghyun; Park, Sunkyu; Nejad, Mojgan; Stahl, Shannon S.; Hegg, Eric L.; Hodge, David B.A two-stage alkaline-oxidative pretreatment of hybrid poplar was investigated at scale (20 L reactor volume) with the goal of understanding how reaction conditions as well as interstage mechanical refining impact downstream process responses. The pretreatment comprises a first stage of alkaline delignification (alkaline pre-extraction) followed by a second delignification stage employing Cu-catalyzed alkaline hydrogen peroxide with supplemental O2 (O2-enhanced Cu-AHP). Increasing pre-extraction severity (i.e., temperature and alkali loading) and pretreatment oxidation (increasing H2O2 loading) were found to increase mass and lignin solubilization in each stage. Lignin recovered from the first stage was subjected to oxidative depolymerization and led to aromatic monomer yields as high as 23.0% by mass. Lignins recovered from the second-stage Cu-AHP pretreatment liquors were shown to exhibit aliphatic hydroxyl contents more than 6-fold higher than a typical hardwood kraft lignin, indicating that these lignins could serve as a biobased polyol for a range of polyurethane applications.Item Extraction, recovery, and characterization of lignin from industrial corn stover lignin cake(Elsevier BV, 2024-05) Bécsy-Jakab, Villő Enikő; Savoy, Anthony; Saulnier, Brian K.; Singh, Sandip K.; Hodge, David B.Lignin utilization in value-added co-products is an important component of enabling cellulosic biorefinery economics. However, aqueous dilute acid pretreatments yield lignins with limited applications due to significant modification during pretreatment, low solubility in many solvents, and high content of impurities (ash, insoluble polysaccharides). This work addresses these challenges and investigates the extraction and recovery of lignins from lignin-rich insoluble residue following dilute acid pretreatment and enzymatic hydrolysis of corn stover using three extraction approaches: ethanol organosolv, NaOH, and an ionic liquid. The recovered lignins exhibited recovery yields ranging from 30% for the ionic liquid, 44% for the most severe acid ethanol organosolv condition tested, and up to 86% for the most severe NaOH extraction condition. Finally, the fractional solubilities of different recovered lignins were assessed in a range of solvents and these solubilities were used to estimate distributions of Hildebrand and Hansen solubility parameters using a novel approach.