Phenomena and Mechanism for Separation and Recovery of Penicillin in Ionic Liquids Aqueous Solution
详细信息 查看全文
- 作者：Yangyang Jiang ; Hansong Xia ; Chen Guo ; Iram Mahmood ; Huizhou Liu
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2007
- 出版时间：September 12, 2007
- 年：2007
- 卷：46
- 期：19
- 页码：6303 - 6312
- 全文大小：809K
- 年卷期：v.46,no.19(September 12, 2007)
- ISSN：1520-5045
文摘
In this paper, an integrated process based on hydrophilic and hydrophobic ionic liquids is proposed to extractpenicillin G from its fermentation broth and recover it into fresh water. With the aid of buffer salt, hydrophilicionic liquids [C4mim]BF4(1-butyl-3-methylimidazolium tetrafluoraborate) could form an ionic liquids aqueoustwo-phase system (ILATPS) and extract penicillin into the ionic liquids-rich phase of ILATPS, while leavingmiscellaneous proteins in the ionic liquids-poor phase. Subsequently, hydrophobic [C4mim]PF6 (1-butyl-3-methylimidazolium hexafluoraphosphate) is introduced into the ionic liquids-rich phase of ILATPS, whichtransfers the system into a hydrophobic ionic liquids phase in equilibrium with a water-phase system (HOILWS).The majority of hydrophilic [C4mim]BF4 is transferred into the ionic liquids-rich phase of HOILWS, leavingmost of the penicillin in the conjugated water phase. In comparison with the butyl acetate/water system orthe polymer-aqueous two-phase system, the integrated ionic liquids system shows several advantages: (1)Penicillin is efficiently extracted into the ionic liquids-rich phase at neutral pH, so the protein emulsificationmet in the organic solvent system is avoided. (2) Hydrophobic ionic liquids could separate hydrophilic ionicliquids away from the penicillin-containing aqueous phase. Consequently, the trouble for recovering the phase-forming material in the polymer-aqueous two-phase system is overcome. Moreover, the experimental resultssuggest that the partitioning behaviors of penicillin in ILATPS and HOILWS are different. In ILATPS, thelogarithm of the partitioning ratio of penicillin (ln K) increases proportionally with the concentration differenceof ionic liquids between ionic liquids-rich and liquids-poor phases (
[ionic liquids]), and the partitioningratio exceeds 1000 at [ionic liquids] = 2.5 mol/L. While in HOILWS, ln K decreases monotonically with[ionic liquids], and more than 90% penicillin could be recovered from the ionic liquids-rich phase of ILATPSwhen the mole ratio of [C4mim]PF6/[C4mim]BF4 exceeds 1. Moreover, the partitioning ratio approaches thatin the [C4mim]PF6/water system when the [C4mim]PF6/[C4mim]BF4 ratio in HOILWS is sufficiently large. Amodified Flory-Huggins model is proposed to elucidate the partitioning behaviors in the two ionic liquidssystems, which emphasizes the key role of energic equilibrium in determining ln K ionic liquids solution. InILATPS, the distance between ionic liquids aggregates is relatively large, which makes the long-range "self-energy" dominating the partitioning behaviors of penicillin. In contrast, in HOILWS the distance betweenionic liquids aggregates is greatly suppressed, which magnifies the entropic loss and hydration repulsionbetween ionic liquids aggregates and makes them as determinants for the partitioning of penicillin in HOILWS.The conclusions from this model are validated by a series of experimental observations, including the salt'stype and concentration, hydrophobic/hydrophilic ionic liquids ratio, and ionic liquids species.
[ionic liquids]), and the partitioningratio exceeds 1000 at [ionic liquids] = 2.5 mol/L. While in HOILWS, ln K decreases monotonically with[ionic liquids], and more than 90% penicillin could be recovered from the ionic liquids-rich phase of ILATPSwhen the mole ratio of [C4mim]PF6/[C4mim]BF4 exceeds 1. Moreover, the partitioning ratio approaches thatin the [C4mim]PF6/water system when the [C4mim]PF6/[C4mim]BF4 ratio in HOILWS is sufficiently large. Amodified Flory-Huggins model is proposed to elucidate the partitioning behaviors in the two ionic liquidssystems, which emphasizes the key role of energic equilibrium in determining ln K ionic liquids solution. InILATPS, the distance between ionic liquids aggregates is relatively large, which makes the long-range "self-energy" dominating the partitioning behaviors of penicillin. In contrast, in HOILWS the distance betweenionic liquids aggregates is greatly suppressed, which magnifies the entropic loss and hydration repulsionbetween ionic liquids aggregates and makes them as determinants for the partitioning of penicillin in HOILWS.The conclusions from this model are validated by a series of experimental observations, including the salt'stype and concentration, hydrophobic/hydrophilic ionic liquids ratio, and ionic liquids species.