Recycling of deep eutectic solvents with membrane technology
Aksoy, Hazal Burcu (2018)
Diplomityö
2018
School of Engineering Science, Kemiantekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2018081333625
https://urn.fi/URN:NBN:fi-fe2018081333625
Tiivistelmä
Penetration towards biomass utilization as an energy source instead of fossil fuels due to its environmental friendliness, leads towards ionic liquid (IL) usage to break lignocellulosic biomass bonds. Deep eutectic solvents (DES) as one kind of ILs are preferred to be used in the place of ILs by reason of mostly environmental advantages. Economic and environmental aspect of the process in terms of amount of utilized solvent, bring about recyclability of DES.
The aim of this study was recycling of deep eutectic solvent (choline chloride: lactic acid, molar ratios 1:9) by membrane filtration to be used again for extraction of lignin from birch wood. Regarding to this, how well is the purification efficiency of the membrane process, as well as lignin extraction efficiency of the purified spent DES are aimed to be answered in consideration of this study. For this purpose, two sets of ultrafiltration, nanofiltration and reverse osmosis membrane utilization in the respective order has been performed as UP005, NF 270, AG and UP005, NFG, AG. In terms of purity, while the membrane process where NF 270 was used as a nanofiltration membrane results in purified spent DES with lignin concentration of 1.30 g/L, membrane process with NFG utilization results in spent DES with higher lignin concentration as 2.63 g/L. This result concludes that higher MWCO membrane utilization as a nanofiltration i.e., NFG, causes higher lignin concentration in the recycled spent DES, thus decreases the purity. In terms of lignin dissolution efficiencies, spent DES from the membrane process where NFG utilization took place, resulted in 32.6% efficiency which is only about 50% of the extraction efficiency of fresh DES.
The aim of this study was recycling of deep eutectic solvent (choline chloride: lactic acid, molar ratios 1:9) by membrane filtration to be used again for extraction of lignin from birch wood. Regarding to this, how well is the purification efficiency of the membrane process, as well as lignin extraction efficiency of the purified spent DES are aimed to be answered in consideration of this study. For this purpose, two sets of ultrafiltration, nanofiltration and reverse osmosis membrane utilization in the respective order has been performed as UP005, NF 270, AG and UP005, NFG, AG. In terms of purity, while the membrane process where NF 270 was used as a nanofiltration membrane results in purified spent DES with lignin concentration of 1.30 g/L, membrane process with NFG utilization results in spent DES with higher lignin concentration as 2.63 g/L. This result concludes that higher MWCO membrane utilization as a nanofiltration i.e., NFG, causes higher lignin concentration in the recycled spent DES, thus decreases the purity. In terms of lignin dissolution efficiencies, spent DES from the membrane process where NFG utilization took place, resulted in 32.6% efficiency which is only about 50% of the extraction efficiency of fresh DES.