| 1. |
- Anugwom, I, et al.
(författare)
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Selective Extraction of Hemicelluloses from Spruce using Switchable Ionic Liquids
- 2012
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 87:3, s. 2005-2011
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Tidskriftsartikel (refereegranskat)abstract
- Switchable Ionic Liquids (SILs) made from alcohols, either hexanol or butanol, and CO2 together with an amidine (1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)) were investigated as dissolution/fractionation solvents for wood material. Both native spruce (Picea abies), and pre-extracted spruce were treated with either butanol SIL (SIL1) or hexanol SIL (SIL 2) for 5 days at 55 °C under normal pressure. The SILs were formed by bubbling CO2 through an equimolar mixture of either 1-hexanol or 1-butanol and DBU. The viscosity of the mixture increased from 7.1 mPas to 2980 mPas for SIL 2 and 5.1 to 1600 mPas for SIL 1. Melting points of the SILs 1 and 2 were at 8 and 14 °C, respectively. After the treatment time (5 days), the undissolved fraction contained 38 wt % less hemicelluloses compared to native spruce. There was an increase in the glucose content of the milled spruce treated with both SILs, since the milling step reduced the cellulose crystallinity of the wood and facilitated an easier SIL access into the wood. The solvents were very neutral in terms of lignin removal. Consequently, only about 2% of the lignin was removed from native wood. Moreover, a priori removal of the wood extractives did not influence the lignin removal. Highlights► Switchable Ionic Liquids made from, either hexanol or butanol, and CO2 together with an amidine (DBU) were studies as dissolution/fractionation solvents for spruce wood. ► After the treatment undissolved fraction contained 38 wt-% less hemicelluloses. ► We conclude that Switchable ionic liquids are effective solvent for fractionation of wood material, and they are easily recycled and can be reused.
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| 2. |
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| 3. |
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| 4. |
- Khokarale, Santosh G., et al.
(författare)
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Switchable polarity liquids
- 2018
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Ingår i: Polymerized ionic liquids. - London : Royal Society of Chemistry. - 9781782629603 - 9781788010535 - 9781788012218 ; , s. 143-179
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter, the synthesis and characterization, as well as applications, of various types of switchable polarity solvents (SPSs) are summarized in order to unravel their composition and switchable nature. The polarity 'switch' between a molecular liquid and ionic species in the case of SPSs is described on the basis of interactions occurring for various types of organic bases or silylamines with acid gases such as CO2 or SO2 and in the absence or presence of alcohols. The chapter consists of two principal parts where the synthesis of SPS systems is described as a result of interaction of one or two molecular components with acid gases. The molecular liquids in two-component SPSs comprise organic superbases such as 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) or 1,1,3,3-tetramethylguanindine (TMG or its derivatives) and lower to higher alcohols or water or glycerol. The one-component system involves the use of silylamines for SPS synthesis. The change in the composition and polarity of the reaction mixture during the synthesis, as well as the switchable nature of these SPSs, is demonstrated by gravimetric, spectroscopic and conductivity measurements. In the second part, various applications of SPS systems are described along with how the special characteristics of SPSs can be utilized.
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| 5. |
- Mäki-Arvela, P, et al.
(författare)
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Dissolution of lignocellulosic materials and its constituents using ionic liquids - a review
- 2010
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Ingår i: Industrial crops and products (Print). - : Elseier B.V.. - 0926-6690 .- 1872-633X. ; 32:3, s. 175-201
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Tidskriftsartikel (refereegranskat)abstract
- The state of art from the dissolution of cellulose, lignin and wood using ionic liquids is presented in this work. The emphasis is put on the relationship between the properties of ionic liquids and the dissolution capacity. The impact of the following solvation parameters, namely Hildebrand solubility parameter and hydrogen bond basicity are related to the dissolution of lignocellulosic material. Good solvents for cellulose are 1-butyl- and 1-allyl-3-methylimidazolium chlorides as well as 1-ethyl-3-methylimidazolium acetate, whereas for lignocellulosic material the best solvents are 1-ethyl-3-methylimidazolium acetate and 1-allyl-3-methylimidazolium chloride. In allyl group the ethylene functionality facilitates B-interactions with the aromatic lignin structure. Furthermore, small polarizable anions are also powerful when aiming at dissolution of cellulose. The properties of regenerated cellulose and reconstituted lignin are also given and compared with those of the native materials. Furthermore, the results from the regeneration and reuse of ionic liquids are presented here.
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| 6. |
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| 7. |
- Anugwom, I, et al.
(författare)
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Ionic liquid assisted extraction of nitrogen and sulphur-containing air pollutants from model oil and regeneration of the spent ionic liquid
- 2011
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Ingår i: Journal of Environmental Protection. - : Scientific Research Publishing. - 2152-2197 .- 2152-2219. ; 2:6, s. 796-802
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Tidskriftsartikel (refereegranskat)abstract
- Removal of air pollutants, such as nitrogen and sulphur containing compounds from a model oil (dodecane) was studied. An ionic liquid (1-ethyl-3-methylimidazolium chloride [C2mim] [Cl]) was used as an extractant. Liquid-liquid extraction by using 1-ethyl-3-methylimidazolium chloride [C2mim] [Cl] was found to be a very promising method for the removal of N- and S-compounds. This was evaluated by using a model oil (dodecane) with indole as a neutral nitrogen compound and pyridine as a basic nitrogen compound. Dibenzothiophene (DBT) was used as a sulphur compound. An extraction capacity of up to 90 wt% was achieved for the model oil containing pyridine, while only 76 wt% of indole in the oil was extracted. The extraction capacity of a model sulphur compound DBT was found to be up to 99 wt%. Regeneration of the spent ionic liquid was carried out with toluene back-extraction. A 1:1 toluene-to-IL wt ratio was performed at room temperature. It was observed that, for the spent ionic liquid containing DBT as a model compound more than 85 wt% (corresponding 3852 mg/kg) could be removed from the oil. After the second regeneration cycle, 86 wt% of the DBT was recovered from the ionic liquid to toluene. In the case of indole as the nitrogen containing species, more than 99 wt%, (corresponding to 2993 mg/kg) of the original indole was transferred from the model oil to the ionic liquid. After the first-regeneration cycle of the spent ionic liquid, 54 wt% of the indole–in-IL was transferred to toluene. Thus, both extractions of nitrogen and sulphur model compounds were successfully carried out from model oil and the back-extraction of these compounds from the ionic liquids to toluene demonstrated the proved the concept of the regeneration point of view.
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| 8. |
- Eta, Valerie, et al.
(författare)
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Enhanced mass transfer upon switchable ionic liquid mediated wood fractionation
- 2014
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Ingår i: Industrial crops and products (Print). - : Elsevier. - 0926-6690 .- 1872-633X. ; 55, s. 109-115
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Tidskriftsartikel (refereegranskat)abstract
- The fractionation of lignocellulosic biomass to its major components is the primary step towards the conversion of biomass-based biopolymers to commodity chemicals in the integrated biorefinery process. Wood chips encased in a SpinChem® device and attached to the stirrer of a batch autoclave were used together with switchable ionic liquids (SILs) for the selective fractionation of hemicelluloses and lignin. Stirring of the wood chips in the SpinChem® device facilitated the diffusion of SIL into the chips through forced recirculation and at the same time avoiding mechanical fibrillation. The treatment of birch chips (Betula pendula) with SILs comprising 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU), monoethanolamine (MEA) and CO2 at 120 °C in a SpinChem® device resulted in the fractionation of 82 wt.% hemicelluloses and 90 wt.% lignin, leaving the cellulose-rich non-dissolved material partially fibrillated and softened. The dissolved hemicelluloses and lignin were selectively precipitated using isopropanol and recovered from the spent SIL.
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| 9. |
- Eta, Valerie, et al.
(författare)
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Loop vs. batch reactor setups in the fractionation of birch chips using switchable ionic liquids
- 2014
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 238, s. 242-248
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Tidskriftsartikel (refereegranskat)abstract
- The fractionation of lignocellulosic feedstock into its major components with high purity represents an important commercialization milestone in the transformation of lignocellulosic forest derived products into fuels and commodity chemicals. A comparison between the traditionally used batch reactor and loop reactor systems demonstrates that improved dissolution of hemicelluloses and lignin are obtained using switchable ionic liquids in a loop reactor system which facilitates decreased heat and mass transfer restrictions. The treatment of birch chips using switchable ionic liquid (SIL) based on 1,8-diazabicyclo-[5.4.0]-undec-7-ene, CO2 and diethanolamine at 120 °C for 30 h in a loop reactor resulted in 24% loss of original weight of wood corresponding to dissolution of 52 wt.% of hemicelluloses and 42 wt.% of lignin, respectively, as opposed to 20% weight loss corresponding to 43 wt.% dissolution of hemicelluloses and 38 wt.% of lignin in the batch system. The non-dissolved material obtained from both reactors was efficiently fibrillated and softened cellulose fibres. The flow of switchable ionic liquid through the loop reactor and agitation of the chips enhanced the dissolution of hemicelluloses and lignin. The dissolved fractions recovered from spent SIL after treatment contained both hemicelluloses and lignin.
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| 10. |
- Kirilin, A, et al.
(författare)
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Chemo-Bio Catalyzed Synthesis of R-1-Phenylethyl Acetate over Bimetallic PdZn Catalysts, Lipase, and Ru/Al2O3 : part II
- 2011
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Ingår i: Kinetics and catalysis. - : Maik Nauka/Interperiodica. - 0023-1584 .- 1608-3210. ; 52:1, s. 77-81
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Tidskriftsartikel (refereegranskat)abstract
- One-pot synthesis of R-1-phenyethylacetate at 70 degrees C was investigated using three different catalysts simultaneously, namely a bimetallic PdZn/Al2O3 as a hydrogenation catalyst, an immobilized lipase as an acylation catalyst and Ru/Al2O3 as a racemization catalyst. The most active bimetallic catalyst was PdZn/Al2O3 calcined at 300 degrees C and reduced at 400 degrees C, whereas the most selective although less active catalyst was the one being calcined and reduced at 500 degrees C. The highest selectivity to R-1-phenylethyl acetate over this catalyst was 32 at 48% conversion. Ru/Al2O3 was confirmed to have a positive effect on the formation of the desired product, although it was not very active in the racemization during one-pot synthesis.
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| 11. |
- Kirilin, A, et al.
(författare)
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Chemo-bio catalyzed synthesis of R-1-phenylethyl acetateover bimetallic PdZn catalysts, lipase and Ru/Al2o3. Part I
- 2011
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Ingår i: Kinetics and catalysis. - Moskva : Nauka. - 0023-1584 .- 1608-3210. ; 52:1, s. 78-82
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Tidskriftsartikel (refereegranskat)abstract
- The effect of calcination and reduction temperature on the physical properties of PdZn/Al2O3 catalysts, prepared by coprecipitation deposition technique and characterized by XPS, XRD and TEM methods are reported. The temperatures were varied in a range of 300–500°C. The catalyst calcined at 300°C and reducedat 400°C exhibited the metal particle size of 2–6 nm and contained the highest surface concentrations of Pd and Zn according to XPS measurements. The size and the fraction of large particles (above 10 nm) increased with increasing the calcinations and reduction temperatures.
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| 12. |
- Kirilin, A, et al.
(författare)
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Mechanistic investigations of the reaction network in chemobiocatalyzed synthesis of R1Phenylethyl Acetate
- 2010
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Ingår i: Kinetics and catalysis. - : Springer. - 0023-1584 .- 1608-3210. ; 51:6, s. 809-815
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Tidskriftsartikel (refereegranskat)abstract
- The kinetics and reaction network of the onepot synthesis of R1phenylethyl acetate was investigated at 70°C in toluene over a combination of three different catalysts: PdZn/Al2O3 as a catalyst for acetophenone hydrogenation, lipase as an enzymatic catalyst for R1phenylethanol acylation with ethyl acetate and Ru/Al2O3 as a racemization catalyst for S1phenylethanol. In addition to the desired reactions, other reactions, namely hydrogenolysis and dehydration of (R, S)1phenylethanol and debenzylation of (R, S)1phenylethyl acetate also occurred. The kinetic results revealed that ethylbenzene formation was enhancedwith higher amounts of PdZn/Al2O3, whereas lipase did not catalyze ethylbenzene formation. Furthermore, ethylbenzene was formed in the hydrogenolysis of (R, S)phenylethanol and in the debenzylation of (R, S)1phenylethylacetate over Pd/Al2O3 catalyst. The presence of Ru/Al2O3 catalyst, in which Ru was in the oxidation state of 3+, enhanced the formation of R1phenylethyl acetate, although no clear racemization of S1phenylethanol during the onepot synthesis of R1phenylethyl acetate was observed. Dynamic kinetic resolution of (R, S)1phenylethanol in toluene, was, however, demonstrated over Ru/Al2O3 and lipase.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Leyton, A., et al.
(författare)
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Identification and efficient extraction method of phlorotannins from the brown seaweed Macrocystis pyrifera using an orthogonal experimental design
- 2016
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 16, s. 201-208
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The brown seaweed contains a type polyphenol compound characteristic of its species, the phlorotannins, which are produced from the polymerization of phloroglucinol units. They have been extensively studied due to their pharmacological and nutraceutical properties, but there is still a need for an optimized extraction protocol. In this study, the brown seaweed Macrocystis pyrifera was employed to determine the best conditions for extraction of phlorotannins. A set of different variables were evaluated such as the use of pre-treatment, type of solvent, drying temperature, particle size, temperature and extraction time as well as the solid/liquid ratio upon extraction. The optimal conditions for the extraction of phlorotannins were: pre-treatment with hexane, extraction with water, drying temperature 40 °C, particle size below 1.4 mm, at 55 °C for 4 h and a solid-to-liquid ratio of 1:15. Under these conditions, the concentration of phlorotannins achieved in the extract was 200.5 ± 5.6 mg gallic acid equivalent (GAE)/100 g dry seaweed (DS) and total antioxidant activity of the extract of 38.4 ± 2.9 mg trolox equivalent (TE)/100 g DS. Further, it was possible to identify two phlorotannins through HPLC-ESI-MS analyses: phloroeckol and a tetrameric phloroglucinol. These phlorotannins have been reported in the literature to have an antidiabetic effect and prevention of Alzheimer's disease for phloroeckol, and free radical scavenging ability and antiallergic effect for tetrameric phloroglucinol. Therefore, the extract of phlorotannins has potential as medicinal foods or therapeutics for human health applications.
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| 18. |
- Leyton, A., et al.
(författare)
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Improvement in carbohydrate and phlorotannin extraction from Macrocystis pyrifera using carbohydrate active enzyme from marine Alternaria sp. as pretreatment
- 2017
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Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 29:4, s. 2039-2048
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Tidskriftsartikel (refereegranskat)abstract
- The commercial importance of brown seaweed has been increasing over the past decade, especially due to industries interested in the extraction of phycocolloids and, more recently, of polyphenol compounds such as phlorotannins. The objective of this work was to optimize the extraction conditions of carbohydrates and phlorotannins from Macrocystis pyrifera, evaluated enzymatic pretreatment and different parameters of extraction using design of experiment. The optimal conditions upon extraction of the carbohydrates and phlorotannins were determined by means of a pretreatment protocol taking advantage on a carbohydrate active enzyme, followed by an alkaline hydrolysis with 0.5 N NaOH at 100 °C, 180 min, and S/L ratio of 1/20. In order to extract the carbohydrates, the best conditions found for the pretreatment procedure were 37 °C, pH 7.0 for 24 h, and a S/L ratio of 1/10, giving an extraction yield (EY) of 89.67 ± 12.3 wt.%. In turn, for the extraction of phlorotannins, the best conditions identified in terms of the pretreatment were 25 °C, pH 7.0 for 36 h, and a S/L ratio of 1/20, thus giving a yield (EY) of 2.14 ± 0.25 wt.%. Statistical analysis of both processes revealed a maximum EY of 91.24 wt.% for carbohydrates and 3.31 wt.% EY for phlorotannins.
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| 19. |
- Pezoa-Conte, R., et al.
(författare)
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Deconstruction of the green alga Ulva rigida in ionic liquids : closing the mass balance
- 2015
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 12, s. 262-273
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Tidskriftsartikel (refereegranskat)abstract
- Algae are known to grow at high rates compared to terrestrial plants that contain comparable amounts of carbohydrates by weight. Therefore, this renders them attractive in terms of any biorefinery concept. In this work the green alga Ulva rigida, containing 40 wt.% of carbohydrates was pretreated with a switchable ionic liquid (SIL), distillable ionic liquid (DIL) and low-viscosity ionic liquid (LVIL). The SIL DBU–MEA–SO2 was prepared from a mixture of mono-ethanolamine (MEA) and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) that was coupled with sulfur dioxide (SO2), whereas the DIL [TMGH+][EtCO2−] (1,1,3,3-tetramethylguanidine propionate) was synthesized by a simple acid–base neutralization reaction. Consequently, the LVIL [HDBU+][5OF−] protonated 1,8-diazabicyclo-[5,4,0]-undec-7-ene- 2,2,3,3,4,4,5,5-octafluoro-1-pentoxide was used as received. The treatments were carried out in the temperature range of 100–160 °C for 6 h. The products obtained after the treatments were analyzed using different techniques like ICP, OES, SEM, TEM, TGA, FTIR and carbohydrate determination by GC. Upon treatment with DIL up to 67 wt.% of carbohydrates could be dissolved. For the first time, processing of U. rigida was carried out in ionic liquids so that the mass balance of the process was obtained. It can be concluded that 1,1,3,3-tetramethylguanidine propionate shows significant potential when aiming at releasing carbohydrates from algal biomass that, consequently, can be applied in the production of platform chemicals and/or biofuels such as bioethanol.
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| 20. |
- Privalova, Elena, et al.
(författare)
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CO2 capture from biogas : absorbent selection
- 2013
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Ingår i: RSC Advances. - : RSC Publishing. - 2046-2069. ; 3:9, s. 2979-2994
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Tidskriftsartikel (refereegranskat)abstract
- The development of proper biogas upgrading technology offers a viable means to utilize biogas in conventional power systems. In this paper, various molecular and ionic solvent systems were evaluated for CO2 removal from biogas in a loop reactor system. The performance of amine solutions, ionic liquids and their mixtures, amino acid salts and solutions blended with piperazine was compared in terms of their CO2 loading capacity. The experimental results revealed that addition of small amounts of piperazine can increase the efficiency of abovementioned solutions on average by 30 vol%. The CO2 capturing capacity of the most promising solvents was in the range of 50-60 L CO2/L absorbent. The regeneration of the solvent mixtures can be challenging since the solvents could loose 16-43 vol% of their initial efficiency upon CO2 release. Ionic liquid [C4mim][acetate] was found to be an efficient VOCs scrubbing media. Moreover, upon use of this ionic liquid, the amount of identified volatile organic compounds (VOCs) in the studied samples was reduced by 65 wt%, while the use of 15 wt% aqueous N-methyldiethanolamine (MDEA) resulted only in 32 wt% reduction in the amount of VOCs.
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| 21. |
- Privalova, E, et al.
(författare)
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CO2 removal with ‘switchable’ versus ‘classical’ ionic liquids
- 2012
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Ingår i: Separation and Purification Technology. - Amsterdam : Elsevier. - 1383-5866 .- 1873-3794. ; 97, s. 42-50
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Tidskriftsartikel (refereegranskat)abstract
- Switchable ionic liquids (SILs) are promising solvents for CO2 separation due to their high CO2 capturing efficiency and easy preparation compared to ‘classical’ ionic liquids. Considering viscosity, the present study has demonstrated that SILs formed at least two times stronger chemical bonds with CO2 than studied classical ionic liquids (ILs). Furthermore, the reversible properties of SILs were confirmed by evaluation of different regeneration methods. On average, molar fractions of CO2 were more than 0.3 outperforming acetate-based ILs (molar fraction of CO2 around 0.25) and more than ten times the capacity of physical ionic liquids (molar fraction 0.02). Consequently, SILs are found to be efficient CO2 absorbents operating at atmospheric pressure.HighlightsComparison of ionic liquid systems acting as chemical vs. physical solvents in practical terms. ► Recycling and reuse issues of ionic liquids in carbon dioxide capture. ► Introduction of new types of switchable ionic liquids. ► Studying the capture-release cycle behavior of the aforementioned ionic liquids. ► In essence, we have focused on engineering aspects.
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| 23. |
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