RT Generic
T1 Separación de lignina y líquidos iónicos de las corrientes generadas en el fraccionamiento de la biomasa mediante el proceso ionosolv
A1 Villarino Viloria, Sara
AB Lignocellulosic biomass is a plentiful and renewable source of feedstock for biorefineries to produce fuels and chemicals. It is cost-effective, widely available, and does not compete with the food industry. The most common method of utilizing biomass is by fractionating this raw material into its primary constituents: cellulose, hemicellulose, and lignin. Cellulose is currently used in the food and textile industries, while hemicelluloses find application in the pharmaceutical sector. Lignin, the second most abundant biopolymer on Earth and the largest aromatic resource available, is often discarded and burned due to its energy value. Therefore, it is crucial to extract and valorise lignin for the development of biorefinery technologies. Ionic liquids can be used to selectively extract lignin from lignocellulosic biomass through the Ionosolv process. The lignin must be isolated from the solution to allow for the reuse of the ionic liquid. Traditionally, this step requires large amounts of water as an antisolvent to precipitate the lignin. However, the excessive use of water during them washing process increases the cost of recovering the ionic liquids, rendering the process economically unfeasible. Therefore, there is a need for alternative solvents to water to selectively extract lignin from ionic liquid solutions. This work investigates the substitution of water with low vaporization enthalpysolvents to favour the recovery of ionic liquids. Lignin was extracted from Eucalyptus wood using an Ionosolv treatment with the ionic liquid 2-hydroxyethylammonium acetate (2-HEAA). After treatment, the lignin remained dissolved in the ionic liquid and was selectively extracted from the solution using alcohols (tert-butanol, 2-propanol, and 1-butanol) as antisolvents. The work examined the effect of solvent volume on lignin extraction yield for three antisolvents, comparing them among themselves and with the base case using water. The energy cost of solvent recovery was also analysed through vaporization enthalpies. The obtained lignin was compared between the two methods: using the examined antisolvents and using water. Gel permeation chromatography (GPC) was used to measure molecular weight distributions, weight-average molecular weights, number-average molecular weights, and polydispersity indexes (PDI). Thermogravimetric analysis (TGA) was employed to assess thermal stability. Fourierxiii transformed infrared spectroscopy (FTIR) and heteronuclear single quantum coherence nuclear magnetic resonance were used to identify the molecular structure of lignin. The data indicates that the maximum lignin precipitation yields from the biomass were 34, 48, and 48 g/ 100 g of lignin in untreated biomass for 1-butanol, 2-propanol, and tert-butanol, respectively, compared to the 56 g/ 100 g of lignin in untreated biomass obtained with water. However, the energy costs per gram of lignin are reduced for the three alcohols, demonstrating that the recovery and reuse of the ionic liquids can be achieved in an economically viable manner using solvents with low vaporization enthalpy. Furthermore, lignins precipitated with alcohols have higher average molecular weights (ranging from 28.000 g/ mol to 31.000 g/ mol) compared to those precipitated with water (16.000 g/ mol). Additionally, the lignins have lower dispersion, with a polydispersity index ranging from 3 to 4,8, compared to those precipitated with water (PDI of 8,4). Furthermore, all the lignins demonstrated exceptional thermal stability at high temperatures. Thus, this study illustrates that the recovery and reuse of the ionic liquid can be simplified by using solvents with low vaporization enthalpy, without compromising the quality of the ionosolv lignin.
YR 2024
FD 2024-07-08
LK https://hdl.handle.net/20.500.14352/114627
UL https://hdl.handle.net/20.500.14352/114627
LA spa
DS Docta Complutense
RD 26 mar 2025