JP2001327803A - Method for separating fat-soluble organic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for separating a harmful fat-soluble organic compound from an object to be treated which contains such a compound. SOLUTION: A rhamno-lipid aqueous solution is mixed in the object containing the fat-soluble organic compound to form an emulsified liquid, the non-emulsified portion is separated from the emulsified liquid and then the remaining emulsified liquid is acidified to have pH<=4 or demulsified by adding metal salt such as iron salt to remove the fat-soluble organic compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for separating a fat-soluble organic compound from an object to be treated containing the fat-soluble organic compound using rhamnolipid. Specifically, rhamnolipids having strong surface-active ability can be used to remove toxic substances such as effluents, exhaust gas, combustion ash, etc. from toxic fat-soluble organic compounds such as dioxins to liposoluble organic substances such as harmful dioxins. The present invention relates to a method for separating a compound.

[0002]

2. Description of the Related Art Generally, wastes containing a toxic fat-soluble organic compound are treated by emulsifying and dispersing the organic compound using a surfactant and then diffusing it into a natural environment such as a river, ocean or soil. Also known as Further, metabolic treatment of toxic fat-soluble organic compounds such as PCBs and dioxins by microorganisms is also known, but these methods are not sufficient as waste treatment of toxic fat-soluble organic compounds, and the method is further increased. The emergence of performance processing methods is awaited.

[0003] Under such circumstances, recently, a technique for treating waste of organic substances using rhamnolipid having a strong surface activity has been developed and proposed. One of them is Nakata et al.'S technology for easily emulsifying rubber-like or paste-like water-in-oil micelles generated by crude oil spillage caused by a ship accident etc. which was previously difficult to emulsify using rhamnolipid. (Japanese Unexamined Patent Application Publication No. 11-290673)
No.).

As described above, it has been found that the emulsion can be demulsified not only by emulsification and dispersion using rhamnolipid but also by adjusting the pH of the emulsion to 4 or less or by adding an iron salt. A technology for recovering oil from waste oil by applying the phenomenon has been proposed at about the same time as the above technology (Japanese Patent Application Laid-Open No. 11-290610).

However, the waste oil treatment technology using these rhamnolipids relates to waste treatment of oily components existing in a large amount, and removes or removes fat-soluble organic compounds from contaminants containing low-concentration fat-soluble organic compounds. It is not related to waste treatment technology such as recovery, and the treatment technology using these rhamnolipids is intended for fine powders, mist, gas, soil, ash, etc., in forms other than the above in which a fat-soluble organic compound is present. Of course, it does not disclose the processing or recovery technique to be performed.

For the recovery of organic compounds from various contaminants containing low-concentration toxic fat-soluble organic compounds containing the above-mentioned substances to be treated, use of an adsorbent is usually considered. If the substance contains solid suspended solids, or is a liquid or extremely viscous object, treatment with the adsorbent is not practical, and it is difficult to recover fat-soluble organic compounds once released into the environment. is there. In particular, organic halides such as fluorocarbons, trichloroethane, tetrachloroethane, and dioxins are known to have an adverse effect on the human body and the environment, and pollution to the environment is often low in concentration and spread over a wide range.

As a method for treating these various fat-soluble organic compounds or contaminants containing the same, recently, there is a case where they are collected from a contaminated site or are forcibly decomposed at the site. In many cases, it is preferable to use a surfactant in order to emulsify and disperse and decompose the fat-soluble organic compound. Such surfactants include, for example, rhamnolipids, which are already known to have very strong emulsifying power and to be biodegradable in small amounts, and the present inventors have actually confirmed them.

[0008] The technology of applying this rhamnolipid from an environmental point of view has already been developed in addition to the above-mentioned special case of treating rubbery or pasty water-in-oil micelles. This includes the example of Muller-hurting et al. (Appl, Eniron, Biot) used to repair soils contaminated with pentadecane.
ech, 32.485, 1990) and other proposals have been approved and their effectiveness has been recognized.However, in all of the examples so far, emulsification promotes diffusion into the natural world and also promotes decomposition by the natural world. It is what we expect.

Since rhamnolipids form chelates with heavy metals, the use of heavy metals for recovery is not yet possible.
rman et al. (Environ. Sci. Technol. 29, 2280-2285, 1995
And Tin et al. (Environ. Sci. Technol. 28, 2404-240)
6, 1994).
No technique for combining and separating fat-soluble organic compounds has been proposed.

[0010]

As described above, the conventional treatment of hazardous wastes containing fat-soluble organic compounds using rhamnolipids is expected only to promote the emulsification and dispersion of fat-soluble organic compounds. As far as the present inventor knows, a technique for separating or recovering a fat-soluble organic compound in hazardous waste using rhamnolipid, which does not fall outside that range, has not been known or proposed.

[0011] In view of such circumstances, the present inventors have focused on the strong surface-active ability, which is a characteristic of rhamnolipids, and utilizing this ability, various objects to be treated containing small or trace amounts of fat-soluble organic compounds, particularly The present inventors have studied whether or not a fat-soluble organic compound can be removed from a harmful material to be treated, and as a result, have succeeded in developing the present invention. Therefore, the present invention can solve the problems of the conventional method of treating harmful substances by simply emulsifying and dispersing a fat-soluble organic compound by using the properties of rhamnolipid having strong surface active ability. However, an object of the present invention is to provide a technique for separating a fat-soluble organic compound from a harmful material to be treated.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a method for separating a fat-soluble organic compound from an object to be treated, in particular, a harmful object to be treated, is a method for separating a fat-soluble organic compound. The object to be treated containing the compound and rhamnolipid are mixed in the presence of water to form an emulsion in which micelles in which the fat-soluble organic compound and rhamnolipid are bonded are dispersed in water, and the emulsion is treated with the harmful substance to be treated. The emulsified liquid is separated from the non-emulsified components, and then the emulsion is de-emulsified. Thereafter, the fat-soluble compound is separated from the aqueous phase.

In the present invention, it has been found that a fat-soluble organic compound contained in a small amount or a small amount in a substance to be treated can be trapped by a rhamnolipid by absorption, extraction, etc., and emulsified and dispersed. Rather than diffusing in nature as it is, it was found that the resulting emulsion containing a fat-soluble organic compound at a low concentration can be de-emulsified and separated from rhamnolipid water, thereby recovering the fat-soluble organic compound. It is now possible to do. As a result, the present invention can provide an excellent harmful object processing technique that does not spill over to the natural world by diffusing a fat-soluble organic compound as in the conventional rhamnolipid processing.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The method for separating a fat-soluble organic compound from an object to be treated according to the present invention comprises, as described above, the step of mixing the object to be treated containing a fat-soluble organic compound and rhamnolipid in the presence of water. The micelles in which the organic compound and rhamnolipid are combined form an emulsion dispersed in water, and the emulsion is separated from non-emulsifying components in the harmful substance to be treated,
Next, the emulsified liquid is de-emulsified, and thereafter, the fat-soluble organic compound is separated from an aqueous phase.

The fat-soluble organic compound to be separated according to the present invention refers to a component which is harmful to the environment, humans and other animals contained in a small or trace amount in various forms of solid, liquid or gaseous substances. It is insoluble or hardly soluble in water, but soluble in organic solvents. The organic compounds include aromatic hydrocarbons, heterocyclic compounds, halogen derivatives of aliphatic hydrocarbons such as alkyl halides, and halogen derivatives of aromatic hydrocarbons. Various chlorine-containing organic compounds such as aromatic hydrocarbon chlorine derivatives and dioxins, which are sometimes said to generate dioxins, are preferable separation targets.

Dioxins are polychlorinated dibenzo-
It is a general term for p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF), and their chemical structures are as shown in structural formula (1). Both structural formulas have 75 and 135 structural isomers, respectively.
Also in the present invention, those are dioxins to be separated.

[0017]

(Equation 1)

The fat-soluble organic compounds to be separated by the present invention other than dioxins include halogenated hydrocarbons, aromatic hydrocarbons such as benzene, petroleum compounds, and organic phosphorus compounds or organic compounds used as agricultural chemicals. There are chlorinated compounds, animal or vegetable fats and oils, etc. Among them, examples of halogenated hydrocarbons include dichloroethane, dichloromethane, trichloroethane, trichloromethane, tetrachloroethane, tetrachloromethane, dichloroethylene and the like.

The object to be treated according to the present invention can be treated in various forms such as gas, liquid or solid as long as it contains a trace amount or a small amount of a fat-soluble organic compound. Contains combustion exhaust gas, manufacturing process exhaust gas,
Alternatively, a fat-soluble organic compound mist-containing gas or the like, a liquid corresponds to drainage, and a solid corresponds to contaminated soil, incinerated ash or sludge. It is also possible to separate fat-soluble organic compounds present in grease-like or water-in-oil type rubber-like micelles.

Regarding the concentration of the fat-soluble organic compound contained in the material to be treated, when the material to be treated is a gas, 1 ng / Nm ^{3 to} 10 mg / Nm ^{3 for} dioxins, and for other fat-soluble organic compounds. 100mg / l to 10g / l
Is good. In the case of liquid, dioxin is 1
pg / l to 1 mg / l, and 0.1 mg / l to 10 g / l for other fat-soluble organic compounds.
0.1 ng / g to 100 ng / g for dioxins,
0.1 mg / g to 900 for other fat-soluble organic compounds
mg / g is good.

The rhamnolipid used for emulsifying and dispersing the fat-soluble organic compound in the present invention is one kind of glycolipid in which rhamnose is bound to a hydroxy fatty acid. Examples thereof include rhamnolipid R1 and rhamnolipid R2, and the two chemical structures are as shown in Structural Formula 2. Rhamnolipid R1, in which two molecules of rhamnose are bonded to a hydroxy fatty acid, has a high surface activity and can be preferably used. When mixing the rhamnolipid with the object to be treated, the rhamnolipid may be used in an aqueous solution previously dissolved in water, or the rhamnolipid may be mixed after the object to be treated and water are mixed, or the object to be treated, Rhamnolipid and water may be mixed at the same time, and a suitable means may be selected depending on the object to be treated.

[0022]

(Equation 2)

In the present invention, an object to be treated containing a fat-soluble organic compound and rhamnolipid are mixed in the presence of water to form an emulsion. For this purpose, a large amount of water is present in the object to be treated. Unless otherwise, water will be added. The addition amount should be equal to or more than the amount of the fat-soluble organic compound, and the content of water should be 10% by volume with respect to the object to be treated.
It is better to add so that it becomes above.

Therefore, if water is originally present in the material to be treated and the content thereof satisfies the above-mentioned conditions, the addition of water is unnecessary. Good. As a preferred method of adding water, it is preferable to add an aqueous solution containing rhamnolipid which satisfies the above-mentioned amount or more to the fat-soluble organic compound, and the concentration of the aqueous solution of rhamnolipid is 0.01 g / l to 100 g / l.
l is better.

In the present invention, when emulsifying and dispersing the fat-soluble organic compound in the object to be treated with rhamnolipid, the treatment form differs depending on the form of the object to be treated.
When the object to be treated is a gas, it is preferred that the gaseous fat-soluble organic compound be passed through an aqueous rhamnolipid solution to be emulsified and dispersed to form an emulsion, for which purpose a spray tower, a packed tower or a tray is used. Various gas-liquid contacting devices such as an absorption tower can be used.

In the case of a liquid, an emulsion can be formed by simply bringing both liquids into contact with each other, so that a liquid-liquid extraction device or a mixing device can be used. Further, when the object to be treated is a solid, since the fat-soluble organic compound in the solid is extracted with an aqueous rhamnolipid solution and emulsified and dispersed so as to form an emulsion, it has a function of mixing and stirring the solid particularly. Various solid-liquid contacting devices can be used.

After forming the emulsion with the fat-soluble organic compound, rhamnolipid, and water, the soil, incinerated ash, dust, sludge, etc. in the non-emulsified material to be treated are separated from the emulsion. Various solid-liquid separation means can be used for the separation, such as gravity extraction, sedimentation separation, centrifugation or filtration.

The liquid obtained by emulsifying the fat-soluble organic compound obtained as described above is subjected to a de-emulsification treatment. In the present invention, the de-emulsification treatment is preferably carried out by acidification treatment to adjust the pH to 4 or less or addition of a metal salt. Iron salts are preferred as metal salts. As the iron salts, ferrous salts and ferrous salts
Although any of iron salts can be used, ferrous salt is preferable in terms of separation performance. FeSO ₄ , Fe
Cl ₂ or FeCl ₃ can be exemplified.

As with iron salts, various metal salts can be used for the de-emulsification treatment. Examples of such salts include salts of various metals such as Al, Ca, and Mg.
l ₂ (SO ₄ ) ₃ , AlCl ₃ , or MgCl ₂ . An iron salt and another metal salt may be used in combination. further,
At the time of the demulsification, an adsorbent such as activated carbon or silica gel is added to the demulsifying liquid at the time of the acidification treatment or the addition of the metal salt to pH 4 or less, so that the performance of separating water and oil can be improved. The acidification treatment for adjusting the pH to 4 or less and the addition of a metal salt may be used in combination.

In the present invention, it has been found that this de-emulsification treatment can separate a fat-soluble organic compound from an emulsion containing a small amount of a fat-soluble organic compound. One of the features of the present invention is that the organic compound can be almost completely extracted or extracted from the object to be treated by rhamnolipid.

After this de-emulsification treatment, the fat-soluble organic compound is separated from the aqueous phase, and an oily component such as an organic solvent or oil or fat can be used for smooth separation. The oily component for separation is used for increasing the amount of oil since the amount of fat-soluble organic compounds in rhamnolipid water is small and it is difficult to collect it from water as it is, and as a result, the fat-soluble It becomes easy to separate from organic compounds. The oily component used for its utilization is added to the rhamnolipid water. The addition is preferably performed during the emulsification treatment, but may be performed after the de-emulsification treatment.

For separation of the fat-soluble organic compound and water, various means can be used as long as they can separate water and oil. Examples thereof include two-layer separation, centrifugal separation, and filtration. . Further, in order to improve the recovery rate of the fat-soluble organic compound, calcium chloride, activated carbon, etc. can be used at the time of oil-water separation after de-emulsification, and by adding these to rhamnolipid water after de-emulsification, fat-soluble organic As described above, the compound can be recovered at a high recovery rate.

When the fat-soluble organic compound is separated from the object to be treated in this manner, the separation means is devised so that the fat-soluble organic compound can be used for any of the fat-soluble organic compounds and for any of the objects to be treated. And a fat-soluble organic compound could be recovered from the object at a ratio of 90% or more. When the separation performance is measured, although the means that can be adopted vary depending on the object to be measured, gas chromatography, liquid chromatography, thin-layer chromatography, porcelain resonance or various simple analyzes (absorbance measurement using a color former, dioxin In such a case, an ELISA method or the like can be used.

[0034]

EXAMPLES Hereinafter, a plurality of experimental examples and examples of the present invention will be described. However, the present invention is not limited to these experimental examples or examples at all, but is specified by the claims. Of course there is.

[Experimental Example 1] Dichloroethylene was selected as a model substance as a gaseous or fly ash-like toxic fat-soluble organic compound, and its solid or aqueous rhamnolipid trapping performance was examined. The experiment was performed as follows. That is, in the case of a solid rhamnolipid, an experiment was conducted not only for rhamnolipid but also for a plurality of other substances in order to compare the capturing ability.

In the experiment, the bottom of the thin layer developing tank was filled with dichloroethane, and small test tubes containing 1 g each of solid rhamnolipid triethanolamine salt, rapeseed oil, activated carbon, and silica gel were put into the thin layer developing tank gas layer. The capture performance of each sample was measured and compared. The measurement was performed by weight measurement over time using an electronic balance, and the results are shown in FIG. From this result, it was found that the solid rhamnolipid captured 1.7 times the amount of dichloroethylene in 4 days, and the solid was maintained at a low capturing amount, so that it was easy to handle. It can also be seen that the trapping ability is superior to silica gel or activated carbon.

In the case of aqueous rhamnolipid, 20
5. A beaker containing 20 ml of a 1 g / l aqueous solution was placed in the thin layer developing tank, and the change over time in the captured weight of dichloroethylene was followed. The weight measurement was performed in the same manner as in the case of the solid. The results show good capture performance depending on the rhamnolipid concentration as shown in FIG.

Example 1 In this example, a small amount of a toxic fat-soluble organic compound attached to a solid is separated and removed.
As an example, a toxic fat-soluble organic compound attached to soil was washed and recovered as follows. Diphenylamine, which is sensitive and easy to detect and quantify, was selected and used as a toxic contaminant. Prior to the experiment, the solubility of diphenylamine was investigated first, and only 16 mg / l was dissolved in water, whereas the rhamnolipid aqueous solution (1 g /
In 1), 125 mg / l was emulsified and dispersed to obtain a homogeneous liquid that looked like an aqueous solution.

After this preliminary investigation, diphenylamine was mixed into the soil, and a recovery test using rhamnolipid water (pH 8.0) was performed as follows. 100m on 50g of black soil
g of diphenylamine in 1 ml of a chloroform solution was impregnated, and sufficiently stirred on a hot plate at 90 ° C. to volatilize chloroform to prepare contaminated soil. The contaminated soil was placed on a filter paper and washed with 250 ml of a 1 g / l rhamnolipid aqueous solution.

After the washing, 50 ml of liquid paraffin was added to the washing solution and the mixture was stirred and emulsified. When the pH was adjusted to 3.7 with hydrochloric acid and the mixture was allowed to stand, oil and water were immediately separated into two complete layers. The addition of the liquid paraffin described above is for increasing the oil content because the concentration of diphenylamine is too low, and it is difficult to recover diphenylamine by oil-water separation using diphenylamine alone.

10 μl of the obtained oil layer was charged into a thin layer of silica gel, developed with methanol, and ninhydrin color development was determined. As a result, it was found that 95% was recovered in the oil layer. The aqueous layer in which 5% (5 mg) of diphenylamine remained was separated using a separating funnel, 400 mg of fish meal and 100 mg of soil were added, and the mixture was stirred at 28 ° C. three times a day for biological treatment. On the seventh day, as a result of quantification by the thin-layer treatment, diphenylamine was 50 μg, and it can be seen that diphenylamine remaining by the biological treatment was reduced to 1/1000. It is recognized that diphenylamine was able to be treated more than the case of biological treatment without recovery with rhamnolipid.

Example 2 This example is an example in which a toxic fat-soluble organic compound is separated and removed from a simulated emulsified liquid artificially prepared, and 4-min is added to 1 L of a 1 g / l aqueous solution of rhamnolipid.
After adding 50 mg of chloro-1-naphthol, a model washing emulsion containing a toxic fat-soluble organic compound was prepared using an ultrasonic oscillator. Then hexane 100m
and further emulsified with stirring. Then, the pH was adjusted to 3.7.
Then, the mixture was left to stand for 10 minutes to de-emulsify and separated into oil and water into two layers.

After separating and removing the lower aqueous layer with a separating funnel, a hexane layer was obtained, which was placed in a rotary evaporator and evaporated to dryness under vacuum. 10 ml of water was added to the obtained evaporated and dried product to dissolve it, and an excess of calcium chloride was added to precipitate a solid containing rhamnolipid. Extraction was performed by adding 10 ml of hexane to the liquid containing the solid to separate rhamnolipid remaining in the oil phase.

After the extraction, the hexane layer was separated and evaporated to dryness under vacuum using a rotary evaporator to obtain 105 mg of a solid. The solid was developed by thin-layer chromatography and quantified. As a result, 47.5 mg (95% recovery) of 4-chloro-1-naphthol could be recovered.
In this solid, calcium chloride remained in addition to the 4-chloro-1-naphthol, and rhamnolipid also remained.

Also, since polychlorinated dibenzofuran, one of the dioxins, is a very dangerous substance and requires careful handling, instead of polychlorinated dibenzofuran, a similar substance, dibenzofuran, having the same basic skeleton is used. When a similar test was performed, a similar recovery was obtained.

In this example, hexane was added before the pH was adjusted to 3.7 because the content of 4-chloro-1-naphthol, which is a harmful fat-soluble organic compound, was too small to be demulsified. Even so, it is difficult to separate oil into two layers by oil-water separation, and this is because the amount of oil is increased in order to perform oil-water separation properly. The operation after oil-water separation is
This is an operation for separating rhamnolipid remaining on the oil side, and this operation step may be performed as necessary in the present invention.

[Example 3] This example is an example in which a small amount of a fat-soluble organic compound is separated by the method of the present invention without adding an organic solvent. When the amount of the fat-soluble organic compound to be mixed is small, it is not possible to smoothly separate and remove the oil-water separation operation by de-emulsification due to the small amount.Therefore, in the above-described embodiment, addition of an organic solvent such as liquid paraffin or hexane is not required. Used together. Therefore, in this example, the possibility of separating the fat-soluble organic compound from the emulsion without adding such an organic solvent was examined.

First, harmful fat-soluble organic compound diphenylamine (D
A) and 1-chloro-3-naphthol (CN) 50 mg
Is added and emulsified to separately prepare liquid emulsions of the harmful substances to be treated. Subsequently, the emulsion is demulsified at a pH of 3.7. The following methods were studied to develop an effective method that does not use the addition of water. In the course of this study, it was found that a fat-soluble organic compound forms flocs in the presence of rhamnolipid and a metal salt.

The separation method studied is as follows. (1) After the pH was adjusted to 3.7, the aqueous phase was separated with a pipette. (2) After the de-emulsification, centrifugation was performed at 15000 rpm for 2 minutes, and the aqueous phase was collected with a pipette. Calcium (CaCl ₂ .2H ₂ O) was added and stirred to a concentration of 1 g / l, and then centrifuged.
After 2 minutes at 5000 rpm, sample the aqueous phase with a pipette

The quantitative determination of the residual harmful fat-soluble organic compound in the collected aqueous phase was carried out as follows. That is, water 20
μl was applied to a thin layer of silica gel and developed with a mixed solution of chloroform: methanol = 80: 15. DA is 235 nm
And the CN was scanned at 250 nm. At the same time, the residual ratio of rhamnolipid (RL) was measured. For the measurement, 20 μl of water was applied to a thin layer of silica gel, developed with a mixed solution of chloroform: methanol: water = 80: 15: 1, orcinol sulfate was developed, and scanning was performed at 550 nm.

The measurement results are as shown in Table 1. According to the results, the acid-soluble treatment alone caused the fat-soluble organic compound to float and disperse due to the trace amount, and as a result, the water from which the fat-soluble organic compound was excluded was removed. Acquisition of a phase is difficult. In addition to this, even when a centrifugal separation operation is used in combination and then the aqueous phase is collected, about 50% of the fat-soluble organic compound is collected with a pipette.

[0052]

[Table 1]

On the other hand, it was found that, when calcium chloride as a metal salt was coexisted under an acidic condition, centrifugation was performed and the aqueous phase was collected, whereby the fat-soluble organic compound could be separated and removed smoothly. Also, at this time, it was found that rhamnolipid, metal salt, and fat-soluble organic compound formed a floc with a large floc as described above, so that centrifugation could be performed smoothly. Similar effects were obtained when various metal salts were added in the same manner as calcium chloride.

As described above, when the amount of the fat-soluble organic compound to be mixed is small, the organic compound cannot be separated and removed smoothly due to the minute amount even if oil-water separation is performed by de-emulsification. It has been found that the separation can be promoted by adding an organic solvent such as hexane. Also,
It has also been found that a fat-soluble organic compound forms a floc when coexisting with a metal salt such as calcium chloride and rhamnolipid under acidic conditions, and can be used to separate it smoothly from the aqueous phase by centrifugation or filtration.

[Example 4] This example is for the purpose of forming the floc based on the above-mentioned findings and investigating the influence of pH on the floc forming ability at that time. 1 g / l of rhamnolipid aqueous solution was added to 1-chloro-3-naphthol (C
N) was added and emulsified by adding 50 mg, and calcium chloride (CaCl ₂ .2H ₂ O) was added to the emulsion at a concentration of 1 g / l. Next, hydrochloric acid was added to the liquid after the addition of calcium chloride to change the pH, and the CN-Ca- formed at each pH by a cellulose acetate membrane having a pore size of 0.45 μm.
The floc consisting of RL was filtered, and the amount of CN in the passing solution was determined by the quantitative method of Example 3 using a thin layer.

FIG. 3 shows the result. According to it, C
N was separated from the aqueous phase at 90% at pH 4 and 95% at pH 3.7. As a result, it can be seen that 90% can be separated and removed below pH 4, and almost all CN can be separated and removed from the aqueous phase.

[Experimental Example 2] In this experimental example, the capturing performance of dioxins by solid rhamnolipid was investigated. Dioxins are extremely dangerous substances and are difficult to handle.
It is extremely dangerous to directly carry out the emulsification-demulsification test corresponding to the examples of the present invention with dioxins, and the above investigation was carried out using 2,3,7,8 TCD as in Experimental Example 1 instead. did. The experiment was performed as follows. 1.0 g of rhamnolipid triethylamine salt,
1.867 ng / 3.3 m of 2,3,7,8 TCD sample
1 (567 ppb) was captured. In addition, the same value was obtained in the capture test with activated carbon performed at the same time, indicating that rhamnolipid had the same performance as activated carbon.

[0058]

According to the present invention, toxic fat-soluble organic compounds such as dioxins, which are contained in small or trace amounts in harmful materials such as wastewater, exhaust gas and combustion ash, have particularly high surface activity. The fat-soluble organic compound is separated and removed by absorbing and extracting with a rhamnolipid aqueous solution, emulsifying and dispersing, and then demulsifying the formed emulsion and separating it from rhamnolipid water. As a result, the present invention provides an excellent treatment technique in which harmful substances after treatment are not diffused to the natural world by diffusing harmful substances after treatment, such as treatment of harmful substances containing a trace amount of a fat-soluble organic compound in the prior art. .

According to the present invention, a small amount or trace amount of a fat-soluble organic compound contained in a harmful material to be treated can be absorbed and extracted by an aqueous rhamnolipid solution and emulsified and dispersed. The present inventors have newly found that a fat-soluble organic compound containing a trace amount can be separated and recovered by a simple de-emulsification treatment, which has been completed, whereby the present invention can exhibit the above-mentioned excellent effects. You can do it.

[Brief description of the drawings]

FIG. 1 shows the results of a test of the ability to capture fat-soluble organic compounds with various capturing agents such as solid rhamnolipid in Experimental Example 1.

FIG. 2 shows the results of a test of trapping performance of fat-soluble organic compounds by aqueous solutions of rhamnolipid at various concentrations in Experimental Example 1.

FIG. 3 shows pH applied to oil-water separation performance in Example 4.
The results of a test investigating the effects of the following are shown.

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Claims (5)

[Claims] An object to be treated containing a fat-soluble organic compound and rhamnolipid are mixed in the presence of water to form an emulsion in which micelles in which the fat-soluble organic compound and rhamnolipid are bonded are dispersed in water. Separating the emulsion from non-emulsifying components in the object, then de-emulsifying the emulsion, and thereafter separating the fat-soluble organic compound from the aqueous phase. How to separate. 2. The method for separating fat-soluble organic compounds according to claim 1, wherein the fat-soluble organic compounds are dioxins. 3. An aqueous solution containing rhamnolipid after the separation of the fat-soluble organic compound is biologically treated to reduce the amount of the fat-soluble organic compound remaining in the aqueous solution.
Or a method for separating a fat-soluble organic compound according to 2. 4. The method for separating fat-soluble organic compounds according to claim 1, wherein the de-emulsification treatment is a treatment for acidifying to pH 4 or less or the addition of a metal salt. 5. The method for separating a fat-soluble organic compound according to claim 4, wherein the adsorbent is added to the demulsifying liquid in the demulsifying treatment.