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Impregnation of Wood Products Past, Present and Future Work
Published in Tatjana Stevanovic, Chemistry of Lignocellulosics: Current Trends, 2018
Diane Schorr, Stéphanie Sabrina Vanslambrouck, Véronic Landry
The paper presents a new method of wood surface impregnation with biopolymers and resins, such as chitosan, zein, gelatine and guaiac resin, by using 1-ethyl-3-methylimidazolium chloride ionic liquid as solvent-carrier. The compounds mentioned diffuse into the wood, and by ionic liquid removal and drying, are able to form a uniform coating. It confers higher moisture resistance, dimensional stability and greater hardness to the treated wood (references). The main advantages of the proposed method of impregnation are the usage of a new solvent (1-ethyl-3-methylimidazolium chloride), and considerably lower temperatures (40°C) than conventional processes of impregnation (100–200°C). Another advantage of the proposed method is the higher solubility of the impregnants in the ionic liquid, as opposed to water or other molecular solvents (references).
An overview of ionic liquid degradation by advanced oxidation processes
Published in Critical Reviews in Environmental Science and Technology, 2022
Ismael F. Mena, Elena Diaz, Juan J. Rodriguez, Angel F. Mohedano
Table 6 summarizes the literature results on the breakdown of 1-ethyl-3-methylimidazolium chloride ionic liquid by different AOPs. As shown, the cation was almost completely degraded in all cases. UV/TiO2 and electro-Fenton processes yielded the highest mineralization (close to 90%), requiring catalysts and electrical energy. In contrast, anodic oxidation and the Fenton–like processes were able to achieve high mineralization (up to 65%) with lower requirements in terms of energy or catalyst. However, it is challenging to develop general conclusions about the best advanced oxidation approach for the treatment of effluent contaminated with ILs because many factors must be considered for cost–benefit analysis. For example, the nature of the IL constituents must be considered because this affects the outcome of each treatment, as well as the efficiency of TOC removal (mineralization). Further, knowledge of the nature of the remaining refractory species and their potential risks to the receiving environment must be known (see Section 3).
One-pot levulinic acid production from rice straw by acid hydrolysis in deep eutectic solvent
Published in Chemical Engineering Communications, 2022
Chenda Hak, Panadda Panchai, Tanawut Nutongkaew, Nurak Grisdanurak, Sarttrawut Tulaphol
The structure of lignocellulose is harmonized by the covalent bonds of lignin-carbohydrate complex (LCC) bonds and highly order hydrogen bonds in crystalline cellulose. To overcome the recalcitrance, harsh conditions at high temperature (>190 °C) and pressure (>650 psi) are required to pretreat and/or fractionate lignocellulose (J. Li, Henriksson and Gellerstedt 2007; Samuel et al. 2011; X. Zhang et al. 2019). However, these harsh conditions cause the degradation of products. Dissolution of lignocellulose in ionic liquids (ILs) such as butyl-3-methylimidazolium chloride ([C4C1im]Cl) and 1-ethyl-3-methylimidazolium chloride ([C2C1im]Cl) disrupts hydrogen bonds in crystalline cellulose, enhancing cellulose accessibility. The dissolved lignocellulose in ILs enabled acid catalyst to hydrolyze cellulose and release sugars in one pot at mild conditions (120–160 °C under atmospheric pressure) (Sun et al. 2013, 2015). Our previous work developed one-pot levulinic acid production of hemp hurd in ionic liquid ([C2C1im]Cl) with high levulinic acid yield up to 47% in mild conditions (170 °C and atmospheric pressure) (Tulaphol et al. 2020). However, ionic liquids show high production efficiency, their cost limits large-scale application.
Cellulose nanocrystals from blueberry pruning residues isolated by ionic liquids and TEMPO-oxidation combined with mechanical disintegration
Published in Journal of Dispersion Science and Technology, 2020
Claudia Marcela Pacheco, Cecilia Bustos A, Guillermo Reyes
Blueberry Pruning Residues (BPRs) were used to obtain cellulose nanocrystals (CNC-IL) isolated by hydrolysis in the ionic liquid 1-ethyl-3-methylimidazolium chloride [emim][Cl] and cellulose nanocrystals with TEMPO-oxidized combined with mechanical disintegration (TOCNC). A significant difference in the shape of the particles of nano-cellulose was found depending on the isolation method. CNC-IL presented an oval shape while TOCNC particles presented a rod-like shaped. The two isolated nanocelluloses showed high colloidal stability and high crystallinity. These nanocellulose products offer new opportunities to develop bioproducts in the context of a circular economy, in areas such as coatings, colloids, among others. The BPRs showed a promising potential to produce nanocellulose diversifying the sources for CNMS production and reducing current incineration practices impacts. In particular, the hydrolysis using IL [emim][Cl] introduced a green chemistry approach, obtaining cellulose nanocrystals with high yield, high thermal stability, and IL recyclability up to 90%.