Institut für Chemie und Bioanalytik
Dauerhafte URI für die Sammlunghttps://irf.fhnw.ch/handle/11654/24
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Ergebnisse nach Hochschule und Institut
Publikation Influence of pulping conditions on the pulp yield and fiber properties for pulping of spruce chips by deep eutectic solvent(Springer, 2023) Pérez, Alan; Roy, Yagnaseni; Rip, Constantijn; Kersten, Sascha R. A.; Schuur, BoeloThe chemical pulping of wood chips using deep eutectic solvents (DES-pulping) has emerged as an alternative technology to conventional pulping in the paper industry, allowing the production of pulp in combination with the recovery of lignin and sugars for valorization. A challenge in the development of this technology is the understanding of how the operating conditions influence the crucial pulp manufacturing parameters such as delignification percentage, pulp yield, and fiber quality. This work is focused on investigating the effect of operating conditions such as cooking temperature, cooking time, liquor-to-wood ratio, initial water content on DES, type of mixing, the addition of a pre-treatment step (pre-impregnation of DES into the wood chips) to cooking process, and DES composition (lactic acid:choline chloride, lactic acid:sodium chloride, and lactic acid:sodium bromide) on the cooking of wood chips by DES. A shortcut quality evaluation parameter (Q), defined as the product of the fiber length and the degree of delignification quantified the quality of the pulping process in a single value, shows values similar to a reference unbleached kraft pulp for cooking at 130 °C in a range of cooking times from 3 to 4.5 h at a L/W of 10:1 by using lactic acid:choline chloride DES. More elaborate property analysis on the fibers showed that several of the the quality-indicating properties of the fibers (coarseness, shape factor, fibril area, and crill index) are comparable with typical sulfite pulping fibers.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Liquid extraction with immobilized liquids for product recovery from fermentation broths(Elsevier, 2022) Pérez, Alan; Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo; Fontalvo, Javier; Thatoi, Hrudayanath; Mohapatra, Sonali; Das, Swagat KumarNowadays, many fermentation chemicals are produced at an industrial scale. Numerous technological improvements have been developed and implemented to achieve high quality and quantity of fermentation products. However, several drawbacks in fermentation processes still limit their application at an industrial level. In situ product removal (ISPR) is a potential alternative to overcome the conventional drawbacks of the fermentative processes, increasing the fermentation's productivity and reducing the separation steps for recovery and purification. Currently, liquid extraction has emerged as a promising separation technology for ISPR, with immobilized liquids such as membrane-assisted extraction and microchannel liquid membrane, due to the high mass transfer rates, scalability, easy integration, and efficiency. This chapter will discuss these technologies regarding their integration into fermentative processes.04A - Beitrag SammelbandPublikation Delignification of low-energy mechanical pulp (asplund fibers) in a deep eutectic solvent system of choline chloride and lactic acid(Frontiers Research Foundation, 09.06.2021) Pérez, Alan; Fiskari, Juha; Schuur, BoeloDeep eutectic solvents (DESs) are considered as a green and environmentally benign solvent class for various applications, including delignification of biomass. One of the major challenges in the delignification of biomass by DES is attributed to the limitations in mass transfer. By subjecting wood chips to a low-energy mechanical refining, i.e., the Asplund process, the accessible surface area increases greatly, which in turn improves the mass transfer and increases the reaction rate. In this research, the DES delignification of Asplund fibers made of Norway spruce was studied as a strategy to produce papermaking fibers under mild conditions. A DES consisting of lactic acid and choline chloride was used due to its proven performance in delignification. Various operational conditions, such as temperature, time, DES-to-wood ratio, and the type of stirring were studied. A novel parameter, Q, allowed to evaluate the impact of the operational conditions on the quality of the pulp in terms of delignification degree and fiber length. The results showed that cooking temperature had the most significant effect on the pulp quality. Additionally, it was observed that cooking times between 30 and 45 min result in a pulp yield of about 50%, while fibers have a lignin content of about 14% and a fiber length of 0.6 mm. These results demonstrate that it is possible to obtain fibers of relatively good quality from DES delignification using Asplund fibers as the starting material.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Electrochemical membrane-assisted pH-swing extraction and back-extraction of lactic acid(Elsevier, 2022) Gausmann, Marcel; Bertram, Franziska; Schuur, Boelo; Jupke, Andreas; Gössi, Angelo; Riedl, WolfgangReactive extraction of carboxylic acids such as lactic acid with tertiary amines is a state-of-the-art process but suffers strongly from reduced extraction efficiency in buffered environments like fermentation broths. In order to increase the efficiency of in-situ product removal, we here propose the combination of a membrane-assisted reactive extraction with an electrochemical pH shift. Prior to extraction in the membrane module, the fermentation broth containing the lactic acid at neutral pH is treated by anodic electrolysis to reduce the pH and thereby improve the extraction yield. Additionally, the cathodic reaction is used to increase the pH of the aqueous stream used for back-extraction of the loaded organic phase. Model solutions were used to develop a mathematical model, capable of calculating the required membrane area for in-situ extractions, considering the effect of the aqueous pH on the extraction performance. Additionally, using electrochemical pH shift, we were able to concentrate lactic acid from 1 wt% in the dilute broth to 7 wt% in the back extract.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Mass transfer analysis and kinetic modeling for process design of countercurrent membrane supported reactive extraction of carboxylic acids(Elsevier, 2021) Schuur, Boelo; Gössi, Angelo; Riedl, WolfgangCountercurrent membrane supported reactive extraction (MSRE) was studied for removal of carboxylic acids from aqueous streams with a PTFE capillary membrane. Analysis of the mass transfer rates was per- formed to support modeling of the process. Total mass transfer coefficients ranging from 2.0 10-7 to 4.0 10-7 m/s were obtained when extracting lactic acid with 20 wt% tri-N-octyl amine in 1-decanol with membrane thicknesses of 260 mm and 80 mm. The limiting mass transfer resistance in all experiments was in the membrane phase. The developed model based on mass transfer and reaction in parallel allows to predict countercurrent extraction. Experimental validation with 5, 7 and 12 m long membrane modules showed excellent accordance for two acids, validating the model simulations. Simulated membrane con- tactor lengths required for single, two and three countercurrent stages varied between 10 and 39 m/stage for lactic, mandelic, succinic, itaconic and citric acid, depending on acid, membrane, and diluent.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Direktextraktion von Milchsäure aus Fermentationsbrühen mittels membrangestützter flüssig-flüssig Extraktion(09/2018) Kohler, David; Gössi, Angelo; Riedl, Wolfgang; Venus, Joachim; Schuur, Boelo06 - PräsentationPublikation Enantioseparation with liquid membranes(Wiley, 2017) Gössi, Angelo; Riedl, Wolfgang; Schuur, BoeloChiral resolution of racemic products is a challenging and important task in the pharmaceutical, agrochemical, flavor, polymer and fragrances industries. One of the options for these challenging separations is to use liquid membranes. Although liquid membranes have been known for almost four decades and have been used for optical resolutions, no comprehensive review has been published about the use of this technology for enantioseparations. In this review, the various liquid membrane-related technologies are described and compared, including bulk liquid membranes, emulsion liquid membranes, micelle-extraction and micellar enhanced ultrafiltration, as well as supported liquid membranes. Next to technological advances, an overview of recent developments in chiral recognition chemistry in liquid–liquid equilibria is presented. The following extractant classes have recently been reported in conjunction with chiral separation: cyclodextrines, BINOL's, calixarenes, crown ethers, BINAP's, tartaric acids and ionic liquids. The use of two supported (non-liquid) membranes with an inner loop of extract phase appears to be the most stable liquid membrane configuration, allowing for a large degree of freedom in operational conditions such as solvent to feed ratio. The library of solvents still needs broadening to make the technology more versatile and based on the variety of successes with catalytically active organometallic complexes, development of new chiral selector systems based on asymmetric catalysis literature is suggested for future selector screening studies. © 2017 Society of Chemical Industry01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Extraction of lactic acid from fermentation broths using membrane supported reactive extraction(2017) Gössi, Angelo; Urso, Alessandro; Riedl, Wolfgang; Schuur, Boelo06 - PräsentationPublikation Extraction and back-extraction of lactic acid from aqueous feeds using membrane supported reactive extraction(11/2016) Riedl, Wolfgang; Gössi, Angelo; Schär, Pascal; Schuur, Boelo06 - PräsentationPublikation Extraction of lactic acid from aqueous feeds using membrane supported reactive extraction(09/2016) Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo06 - Präsentation