KR101372258B1 - Sepported ionic liquid membrane for recovery of butanol from real fermentation broth and preparation method thereof - Google Patents

Abstract

The present invention relates to a separation membrane capable of effectively separating and recovering butanol from a fermentation broth by applying trihexyl tetradecylphosphonium bis (trifluoromethylsulfonyl) imide, which is an ionic liquid, to a porous support. By using the separator to which [Ph3t] [NTF] is applied as the ionic liquid according to the present invention, the recovery rate of butanol can be improved. In particular, [Ph3t] [NTF], applied as an ionic liquid, is very stable, exhibits high selectivity for butanol, and due to its biocompatibility to the solvent-borne Clostridia, a microorganism used to produce fermentation broth, butanol during fermentation. It has the advantage that it is very suitable for the system for recovering

Description

Membrane for recovering butanol from fermentation broth and method for manufacturing thereof {SEPPORTED IONIC LIQUID MEMBRANE FOR RECOVERY OF BUTANOL FROM REAL FERMENTATION BROTH AND PREPARATION METHOD THEREOF}

The present invention relates to a separation membrane for recovering butanol from a fermentation broth and a method for preparing the same, and more particularly, by applying trihexyl tetradecylphosphonium bis (trifluoromethylsulfonyl) imide as an ionic liquid to a porous support. It relates to a separation membrane and a method for producing the same that can effectively separate and recover butanol from the fermentation broth.

Butanol has a higher energy content and higher hydrophobicity than ethanol, making it a better substitute for gasoline than ethanol. As a way to lower the dependence on petroleum-based gasoline, there is again a growing interest in producing butanol from biomass fermented using solventogenic bacteria. This is a classical technique, which has a limitation in that the concentration of the butanol product finally produced through fermentation is very low, such as 0.5 to 1.0 wt%.

Pervaporation is suitable for the butanol separation process due to the major advantages of high selectivity, low energy consumption and simple and easy operation. Integrated fermentation-pervaporation systems have been demonstrated to increase butanol yield. According to this system, the fermentation broth after purification can be removed with butanol in the associated fermentation-pervaporation process, and the butanol depleted residue is returned to the fermentation tank. In this way, the butanol concentration in the fermentation broth is maintained at a nontoxic level suitable for microorganisms.

For the purpose of recovering the solvent from the real fermentation solution, PDMS membranes filled with polydimethylsiloxane (PDMS) and zeolite (zeolite) have been studied. Pure PDMS has proved to be stable in alcohol transport properties, but provides only moderate transport properties and selectivity. The addition of zeolite to pure PDMS can greatly improve the performance of PDMS. However, according to a recent fermentation broth application study, it was found that the membranes filled with inorganic substances are frequently contaminated due to the formation of ester byproducts from organic acids and alcohols due to the catalytic activity of zeolites.

Among the currently developed permeation membranes, the supported liquid membrane (SLM) has the potential for excellent selectivity and fluidity, where molecular diffusion in liquids occurs much faster than in solids and much more for certain ions or molecules. It may be optional. However, the industrial application of SLM is limited by the disadvantage that liquid membrane extraction solvents are easily leached or separated from the support during use.

Room temperature ionic liquids (RTILs) are designer solvents because they can be chosen from a diverse collection of cation-anion combinations or designed as task-specific liquids with desired properties. It is called. When extracting organics from an aqueous phase, RTIL is suitable as a liquid membrane extraction solvent in that it must have high solvent capacity, sufficient hydrophobicity or incompatibility with water, low or no vapor pressure, wide range of liquid temperature, good viscosity and surface tension. Do.

Many ionic liquids have been studied as extraction solvents, but practically, they are rarely applied to industrial applications. RTILs of the phosphonium cationic type are particularly promising because they can provide very high hydrophobicity and significant affinity for organics when the proper anion is selected. In addition, RTIL is considered to be inexpensive and chemically and thermally more stable than ionic liquids of the prior art. Many of these have been found to be able to replace common polymer membranes used as SLM support matrices.

Korean Unexamined Patent Publication No. 2010-0085557, Claims 1-4

It is an object of the present invention to provide a separator for selectively and efficiently recovering butanol from a real fermentation broth.

Another object of the present invention is to provide a method for effectively recovering butanol from the actual fermentation broth using the separation membrane of the present invention.

Still another object of the present invention is to provide a method for preparing a separation membrane for recovering butanol from a real fermentation broth.

The present inventors intensively studied the support ionic liquid pervaporation membrane, and found that ions that are stable and biologically suitable trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide ([Ph3t] [NTF]) for porous supports It has been found that butanol can be effectively recovered from the fermentation broth by using a membrane applied with a liquid solution.

The present invention provides a separator for recovering butanol from a fermentation broth comprising a porous support and an ionic liquid contained in the porous support, wherein the ionic liquid is represented by the following Chemical Formula 1.

[Chemical Formula 1]

The porous support according to the present invention may be a porous support of various materials such as ceramics, polymers, metals, and the like, and is not particularly limited. Preferably, the porous support according to the invention is one selected from the group consisting of single layer polypropylene, polysulfone and polyvinylidene fluoride (PVDF).

The porous support according to the present invention preferably has pores of nanoporous or microporous. Impregnation with ionic liquids in the pores of this size is optimized.

The separator of the present invention is very suitable for the use for recovering butanol from fermentation broth. The fermentation broth according to the invention is preferably a biomass fermented by microorganisms. At this time, the microorganism is particularly preferably a Solventogenic Clostridia strain.

The present invention also provides a method for recovering butanol from fermentation broth using the separation membrane according to the invention.

In addition, the method for producing a separator for recovering butanol from the fermentation broth of the present invention comprises the steps of: (S1) impregnating the porous support in the ionic liquid; And (S2) removing the excess ionic liquid, wherein the ionic liquid is represented by the following Chemical Formula 1.

[Chemical Formula 1]

First, in step S1, the ionic liquid may be injected into the porous support by impregnating the porous support with the ionic liquid. In this case, the ionic liquid uses a compound represented by Chemical Formula 1, that is, trihexyl tetradecylphosphonium bis (trifluoromethylsulfonyl) imide ([Ph 3t] [NTF]).

The porous support according to the present invention may be a porous support of various materials such as ceramics, polymers, metals, and the like, and is not particularly limited. Preferably, the porous support according to the invention is a single layer polypropylene, polysulfone, polyvinylidene fluoride (PVDF). The porous support according to the present invention preferably has pores of nanoporous or microporous.

In addition, the step S1 according to the present invention may further include adjusting the viscosity by diluting with a solvent. In this case, the solvent used is not particularly limited as long as the butanol partition coefficient is high, but oleyl alcohol is preferable. The solvent used can be removed by evaporation under vacuum.

After step S1 of injecting the ionic liquid into the porous support, step S2 is performed to remove excess ionic liquid from the surface of the porous support.

The specific method of removing excess ionic liquid can use any conventionally known technique and is not particularly limited. According to one embodiment according to the invention, it can be carried out by wiping.

When the butanol is recovered from the fermentation broth, when the [Ph3t] [NTF] is applied to the porous support according to the present invention as the ionic liquid, the recovery of butanol may be improved.

In addition, [Ph3t] [NTF], applied as an ionic liquid, is very stable, exhibits high selectivity for butanol, has high biocompatibility, and is almost toxic to the strains of Solventogenic Clostridia, a microorganism used to produce fermentation broth. It has the advantage that it is very suitable for the system for recovering butanol during fermentation.

1 is a graph showing the solvent production activity and glucose uptake of (a) Clostridium acetobutylicum and (b) Clostridium beijerinckii in the daily shake or non-shaken culture according to Experimental Example 1. FIG.
2 is a result of measuring the pervaporation performance of the membrane prepared in Example 1 using butanol / water model solution, Figure 2 (a) is a butanol flux according to the butanol composition and supply temperature in a butanol-water solution 2, (b) shows butanol separation coefficient according to butanol composition and feed temperature.
FIG. 3 is a result of measuring the pervaporation performance of the membrane prepared in Example 2 using a fermentation broth consisting of ABE (acetobe-butanol-ethanol) -water and ABE-acetic acid + butyric acid-water. a) means butanol flux and separation coefficient according to the feed temperature in the four-component fermentation broth (acetone-butanol-ethanol-water), Figure 3 (b) is supplied when the organic acid is additionally supplied in the four-component system when the butanol concentration increases Butanol permeability according to the pH of the solution, that is, means (permeance) (permeance) and selectivity change.
Figure 4 is a graph showing the results of testing the long-term (up to 100 hours) permeation evaporation performance according to the pH change of the separator prepared in Example 2.
5 schematically shows a method of manufacturing a separator according to Example 1.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example  One: [ Ph3t ] [ NTF ] Preparation of Membranes Using

5 shows a method of manufacturing a separator according to the present embodiment.

Specifically, Celgard® obtained from Celgard Corporation as a porous support  2400 (thickness: 25 µm, porosity: 37%, mass transfer area: 6.42 × 10 ⁻⁴ m 2) was prepared. A 57 mm diameter circular porous support was impregnated under vacuum in 0.2 ml of ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide ([Ph3t] [NTF]) (obtained from Aldrich) The ionic liquid was injected into the internal pores of the porous support. A 25 μm thick membrane was prepared by carefully blotting with microscopic filter paper and wiping the surface of the porous support with a lint-free tissue paper to remove excess ionic liquid.

Example  2: [ Ph3t ] [ NTF ] Preparation of Membranes Using

Celgard® obtained from Celgard Corporation as a porous support  A separator having a thickness of 25 μm was prepared in the same manner as in Example 1 except that A273 (thickness: 15 μm, porosity: 40%, mass transfer area: 6.94 × 10 ⁻⁴ m 2) was used.

Experimental Example  One: [ Ph3t ] [ NTF ]of Clostridia  Toxicity measurement

The toxicity of [Ph3t] [NTF] to Clostidium acetobutylicum and Clostidium beijerinckii , which is used industrially in the conventional fermentation process, by fermentation by adding [Ph3t] [NTF] as a poison in the culture. The fermentation medium used was Tryptone-yeast extract-acetate (TYA), and the dilution water was used to change the% saturation concentration of [Ph3t] [NTF] to 0% (control), 30%, 50% and 100%, respectively. It was prepared according to the standard formulation except that it was previously saturated.

Figure 1 shows the solvent production activity and glucose uptake of (a) Clostidium acetobutylicum and (b) Clostidium beijerinckii in daily shake or non-shaken culture. From Fig. 1, [Ph3t] [NTF] is Clostridium not only in shaking but also in shaking conditions. acetobutylicum and Clostridium beijerinckii Both strains were found to have little toxicity in growth and solvent productivity.

Biocompatibility was determined by considering glucose uptake and solvent (acetone, butanol, ethanol) production activity according to the following formula:

In this case, C _GC is the total amount of glucose consumed (g / L), CTS is the total amount of solvent produced (g / L), n is the number of treatments, ctrl means a control.

The biocompatibility of Solvenogenic Clostridia strains used industrially in the conventional fermentation process of [Ph3t] [NTF], an ionic liquid demonstrated in Experimental Example 1, is incorporated into a system in which the fermentation-pervaporation process is integrated. It is possible to apply the separator according to. This provides the advantage of improving productivity through in-stiu butanol product removal.

Experimental Example  2: Measurement of Permeation Evaporation Performance of Membrane

The pervaporation performance of the separator prepared in Examples 1 and 2 was measured.

First, the pervaporation performance of the separator ([Ph3t] [NTF] SILM) prepared in Example 1 was measured using a butanol / water model solution, and the results are shown in FIG. 2. (A) of FIG. 2 means butanol flux according to butanol composition and supply temperature in an aqueous butanol-water solution, and FIG. 2 (b) shows butanol separation coefficient according to butanol composition and supply temperature. From FIG. 2, butanol flux and separation coefficient were increased as the butanol composition of the feed solution was increased when using the separator according to the present invention. On the other hand, butanol flux increased with increasing feed temperature, but the butanol separation coefficient gradually decreased after peaking at a feed temperature of 60 ° C.

In addition, permeation performance of the membrane prepared in Example 2 was measured using a fermentation broth consisting of ABE (acetone-butanol-ethanol)-water and ABE-acetic acid + butyric acid-water. The composition of the feed solution of ABE (g / L) was 5: 15: 1.5 for A and 5: 25: 1.5 for B, and the organic acids (acetic acid + butyric acid) in the fermentation broth were each present at a concentration of 1.5 g / L. 3 (a) means butanol flux and separation coefficient according to the supply temperature in the four-component fermentation broth (acetone-butanol-ethanol-water), Figure 3 (b) is an organic acid added in the four-component system when the butanol concentration increases Butaneol means a change in butanol permeability, that is, permeance (permeance) and selectivity according to the feed solution pH when supplied to. The butanol flux increases with increasing feed temperature but the butanol separation coefficient increases up to 40 ° C and is constant at higher temperatures. On the other hand, the membrane permeation performance according to the pH of the feed solution shows a stable result unchanged.

Experimental Example  3: Permeation Evaporation Performance and Stability Test Using Fermentation Broth

Permeation for a long period of time (up to 100 hours) using a membrane prepared in Example 2 and a fermentation broth consisting of ABE (acetobe-butanol-ethanol) -water and ABE-acetic acid + butyric acid-water used in Experimental Example 2 Evaporation performance was tested and the results are shown in FIG. 4. From FIG. 4, it was proved that the separator according to the present invention is very stable, and can be used for a long time in the pervaporation of butanol from the fermentation broth. This stability is a combination of advantages such as hydrophobicity, viscosity, surface tension and affinity with the support of [Ph3t] [NTF] used as an ionic liquid.

Claims (10)

It consists of a porous support and an ionic liquid contained in the porous support,
The porous support is polysulfone or polyvinylidene fluoride (PVDF),
Separation membrane for recovering butanol from the fermentation broth, characterized in that the ionic liquid is represented by the following formula (1).
[Chemical Formula 1]

The method according to claim 1,
The porous support is a separation membrane for recovering butanol from the fermentation broth, characterized in that having pores of nanoporous or microporous. delete The method according to claim 1,
The fermentation broth is a separation membrane for recovering butanol from the fermentation broth, characterized in that the biomass fermented by a microorganism. The method of claim 4,
The microorganism is a separation membrane for recovering butanol from the fermentation broth, characterized in that the Solventogenic Clostridia strain. A method for recovering butanol from a fermentation broth using the membrane according to any one of claims 1, 2, 4 and 5. (S1) impregnating the porous support with the ionic liquid; And
(S2) removing the excess ionic liquid,
The porous support is polysulfone or polyvinylidene fluoride (PVDF),
The ionic liquid is a method for producing a separator for recovering butanol from the fermentation broth, characterized in that represented by the formula (1).
[Chemical Formula 1]

The method of claim 7,
The step S1, the method of producing a separation membrane for recovering butanol from the fermentation broth, characterized in that it further comprises the step of adjusting the viscosity by diluting with a solvent. The method of claim 7,
The porous support is a method for producing a separation membrane for recovering butanol from the fermentation broth, characterized in that the pores of nanoporous or microporous. delete

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