JP2006239640A - Microreactor for oxidative decomposition of hardly decomposable organic compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microreactor for oxidative decomposition of a hardly decomposable organic compound which is firstly capable of obtaining precise and accurate data with respect to oxidation and decomposition of the hardly decomposable organic compound and, moreover, is secondly capable of obtaining precise and accurate data likewise while maintaining excellence in efficiency aspect and time aspect. <P>SOLUTION: In the microreactor 1, a first fluid 3 including a hardly decomposable organic compound 2 and a second fluid 11 including ozone and hydrogen peroxide flow through a micro-passage 4 having a fine structure in which a photocatalyst 18 is attached to a passage formation surface 21 to form a laminar stream and ultraviolet rays are applied from a ultraviolet irradiation means 19 oppositely arranged. Further based on molecular diffusion on an interface 22 between the first fluid 3 and the second fluid 11 and on an interface 24 between the first fluid 3 and the photocatalyst 18, the hardly decomposable organic compound 2 in the first fluid 3 is oxidized and decomposed by generated OH radicals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a microreactor for oxidative decomposition of a hardly decomposable organic compound. That is, the present invention relates to a microreactor used for oxidizing and decomposing a hardly decomposable organic compound contained in a fluid and acquiring the data.

《Technical background 1》
The wastewater containing the hardly decomposable organic compounds discharged from the chemical treatment facility is usually biologically treated as it is.
For example, a large amount of waste water containing dioxin, bisphenol A (BPA), monochlorobenzene CB, methyl isobutyl ketone MIBK, benzyl alcohol BA, isopropyl alcohol IPA, dimethylformamide DMF, etc. In particular, it was transported to a remote general storage by a tank truck, etc., and biologically treated by the activated sludge method.
However, regarding this technical background 1, problems have been pointed out in the processing equipment, processing capacity, processing time, processing cost, and the like. That is, firstly, large processing facilities such as a large storage tank, a transport tank lorry, a general storage for biological processing, etc. are required, and furthermore, these processing facilities have limited processing capacity and long-term processing. Problems such as a long time and high processing costs were pointed out.

《Technical background 2》
On the other hand, attempts have been made to disassemble and dispose of such wastewater at the site of chemical treatment equipment, that is, at the discharge site without being transported to a general storage. Typically, ozone O ₃ is used to oxidize, decompose, and purify persistent organic compounds contained in wastewater into carbon dioxide CO ₂ or water H ₂ O to produce general waste water drains. It was also attempted.
However, this Technical Background 2 has been pointed out that oxidation and decomposition of difficult-to-decompose organic compounds are very slow, the decomposition reaction does not proceed, and it is easy to stop incomplete and uncertain. .
That is, the decomposition of chain hydrocarbons such as olefinic compounds and paraffinic compounds such as methyl isobutyl ketone MIBK, isopropyl alcohol IPA, and dimethylformamide DMF by ozone O ₃ has stopped until the ozonide ozonide stage. In other words, the ozonide was formed to break the bond and proceed to the aldehyde stage, but the subsequent decomposition reaction was extremely time consuming and difficult to proceed.
In addition, decomposition of cyclic hydrocarbons having aromatic rings such as monochlorobenzene CB and benzyl alcohol BA and other cyclic hydrocarbons by ozone O ₃ has been stopped by the glyoxal (CHO-CHO) stage. In other words, even if it progressed, it was at most to the level of aldehydes containing glyoxal, and the subsequent decomposition reaction was extremely time consuming and difficult to proceed.
As described above, the attempt to purify at the discharge site has been difficult to realize within a time allowed for industrial oxidation and decomposition, and has not been put to practical use.

《About conventional technology》
In view of this situation, the inventor first overcomes the problems of the technical background 1 and is excellent in processing equipment, capacity, time, cost, etc., and secondly, the problems of the technical background 2. Researched and developed an oxidative decomposition apparatus for persistent organic compounds that can overcome these points and oxidize and decompose persistent organic compounds quickly and reliably, and filed a patent application as Japanese Patent Application No. 2005-022495. .
The purification apparatus for the oxidative decomposition apparatus is characterized in that ozone O ₃ and hydrogen peroxide H ₂ O ₂ are introduced into the wastewater in advance, and in combination with this, a photocatalyst and ultraviolet irradiation means are employed. .
That is, in this purification apparatus, the photocatalyst and ozone O ₃ or hydrogen peroxide H ₂ O ₂ are irradiated with ultraviolet rays, and the photocatalyst, ozone, and ozone are generated by the strong oxidizing power and decomposition power of the generated OH radicals. Due to the synergistic effect of combined use with hydrogen peroxide, the more powerful oxidative and decomposing powers allowed quick and reliable oxidation of the hard-to-decompose organic compounds to decompose them into carbon dioxide and water, thereby purifying the waste water. .

By the way, the following points have been pointed out regarding such conventional technology.
About the first point
First, it is not easy to collect accurate data on oxidation and decomposition of hardly decomposed organic compounds.
In other words, this oxidative decomposition apparatus and purification apparatus are excellent because they can oxidize and decompose hardly decomposed organic compounds for the first time reliably and rapidly. Therefore, we are at the stage of research, testing, and experimentation, aiming at practical application. And, using a full-scale experimental machine of the purification device, various data are acquired in batch, but precise data, quantitatively stable data, data based on controlled reactions controlled by conditions, It was difficult to obtain accurate data.
That is, in the experimental apparatus of this purification apparatus, ozone O ₃ and hydrogen peroxide H ₂ O ₂ are introduced into waste water containing a hardly decomposable organic compound and flow as a turbulent flow, while ultraviolet rays are generated in the photocatalyst. Irradiated.
In this way, wastewater becomes turbulent, mixing of contained substances progresses, mass transfer in the order of substances is active, diffusion with a long diffusion distance is performed, etc., and it is difficult to obtain accurate data. . External conditions other than the intended pure reaction are intricately entangled, and depending on the external conditions, the target oxidation and decomposition reactions cannot be adequately controlled, and other substances such as by-products are mixed in. It was easy, and it was difficult to obtain quantitatively stable data, such as expanding the range of target oxidation and decomposition reactions.
For example, the flow rate of wastewater, the type of persistent organic compounds, concentration, oxidative degradation rate, ultraviolet wavelength, irradiation time, photocatalyst composition, adhesion mode, ozone O ₃ and hydrogen peroxide H ₂ O ₂ status, It was difficult to obtain accurate data on temperature conditions, relationships between points, etc.

<< About the second indication >>
Secondly, it took time to acquire data, and a large amount of drainage was used, so the efficiency was poor.
That is, as described above, since the data was acquired batch-wise using a full-scale experimental apparatus of the purification device, the efficiency was low and the reaction rate was slow for the purpose of data acquisition. For example, one data acquisition It took several hours to complete. In addition, a large amount of waste water, ozone O ₃ , hydrogen peroxide H ₂ O ₂ , a photocatalyst, etc. are used, and ultraviolet irradiation over a long period of time is required.

<< About the present invention >>
The microreactor for the oxidative decomposition of the hardly decomposable organic compound of the present invention has been made as a result of the inventors' diligent research efforts in order to solve the above-mentioned problems of the prior art.
Then, the first fluid containing the hardly decomposable organic compound and the second fluid containing ozone or hydrogen peroxide flow as a laminar flow through the microchannel to which the photocatalyst is attached, and are irradiated with ultraviolet rays. Is done. The generated OH radicals oxidize and decompose the hardly-decomposable organic compound of the first fluid based on molecular diffusion at the interface.
Therefore, the present invention firstly proposes a microreactor for oxidative decomposition of difficult-to-decompose organic compounds, which is capable of obtaining precise data of oxidation and decomposition, and secondly, excellent in efficiency and time. The purpose is to do.

<About each claim>
The technical means of the present invention for solving such a problem is as follows. First, claim 1 is as follows.
The microreactor for oxidative decomposition of a hardly decomposable organic compound according to claim 1 is used for oxidizing and decomposing a hardly decomposable organic compound contained in a fluid, and includes a micro flow path having a fine structure. Yes.
The microchannel is supplied with a first fluid containing the organic compound and a second fluid containing ozone or hydrogen peroxide, and an ultraviolet irradiation means is disposed opposite to the microfluidic channel. The photocatalyst is adhered to the flow path forming surface.
Claim 2 is as follows. The microreactor according to claim 2 is the microreactor according to claim 1, wherein an inlet portion of the microchannel is branched in a substantially Y shape, and the first fluid is press-fitted from one inlet and from the other inlet. The second fluid is press-fitted.
In the microchannel, the first fluid and the second fluid are brought into interface contact with each other while forming a laminar flow. At the same time, OH radicals generated by the photocatalyst and the ozone or hydrogen peroxide by the ultraviolet irradiation by the ultraviolet irradiation means cause the interface between the photocatalyst and the first fluid, the second fluid, and the first fluid. And oxidizing and decomposing the organic compound of the first fluid based on molecular diffusion.

Claim 3 is as follows. The microreactor according to claim 3 is characterized in that, in claim 2, the microchannel has a channel width of about 100 μm to about 500 μm and a channel depth of about 25 μm to about 100 μm. And
Claim 4 is as follows. In the microreactor according to claim 4, in claim 3, the organic compound is composed of a paraffinic compound, an olefinic compound, other chain hydrocarbons, a cyclic hydrocarbon having an aromatic ring, and other cyclic hydrocarbons. It is characterized by this. A microreactor for oxidative decomposition of a hardly decomposable organic compound according to claim 3.
Claim 5 is as follows. The microreactor according to claim 5 is the microreactor according to claim 3, wherein an addition channel is connected in the middle of the microchannel, and the addition channel passes the second fluid for replenishment to the microchannel. It press-fits with respect to a 2nd fluid, It is characterized by the above-mentioned.

<About action>
The microreactor for oxidative decomposition of the hardly decomposable organic compound of the present invention is as described above, and is as follows.
(1) The microchannel has a fine structure with a channel width of about 100 μm to 500 μm and a channel depth of about 25 μm to 100 μm.
(2) The inlet portion of the microchannel is branched in a substantially Y shape, and a first fluid containing a hardly decomposable organic compound is press-fitted and supplied from one inlet, and ozone or A second fluid containing hydrogen peroxide is press-fitted and supplied. The second fluid is also press-fitted and supplied from a supplementary addition flow path in the middle.
(3) Since the Reynolds number is small, the first fluid and the second fluid in the microchannel are each laminar and flow in parallel while contacting at the interface.
(4) At the same time, ultraviolet rays are irradiated from the ultraviolet irradiation means, and OH radicals are generated by the photocatalyst on the flow path forming surface and ozone or hydrogen peroxide of the second fluid.
(5) The OH radical has a strong oxidizing power and decomposing power, and is based on molecular diffusion at the interface between the photocatalyst and the first fluid and the interface between the second fluid and the first fluid, respectively. Oxidizes and decomposes organic compounds. A hardly decomposable organic compound is cleaved at a carbon chain and an organic bond, rapidly and reliably oxidized, and decomposed into carbon dioxide gas, water and the like.
(6) The first fluid is discharged from the outlet together with the second fluid.

(7) The present invention is as follows. First, since the microchannel is fine, the interface of the laminar flow such as the first fluid has a very large surface area per unit volume. Accordingly, the oxidation and decomposition of the organic compound by the OH radical is efficiently and directly promoted at the interface with the second fluid and the photocatalyst.
At the same time, the first fluid, etc. is laminar, and the diffusion of the substance is (in the case of mass transfer with a long diffusion distance in the direction perpendicular to the flow direction and in the channel width direction as in the case of turbulent flow. Only) molecular diffusion with a short diffusion distance at the interface. Therefore, oxidation and decomposition by OH radicals are carried out efficiently and purely without being affected by other external conditions and other substances.
As a result, the oxidation and decomposition of the organic compound is controlled quantitatively and stably, so that precise data can be obtained.

Second, since the organic compound is oxidized and decomposed by molecular diffusion at the microscopic microscopic reaction field, that is, at the laminar flow interface of the microchannel, the efficiency is improved and the time is shortened.
For example, since the microchannel has a very small channel width, the temperature gradient and pressure gradient from the interface that governs molecular diffusion in the channel width direction and the channel formation surface are relatively large with respect to the channel width. Also, for this reason, heat conduction is also excellent, and the diffusion distance of molecular diffusion is remarkably small, so that it is excellent in terms of efficiency and time. It should be noted that the amount of the first fluid, the second fluid, the organic compound, ozone, hydrogen peroxide, and the like used, and the ultraviolet irradiation, etc. are very small.

<Features of the present invention>
Thus, the microreactor for oxidative decomposition of the hardly decomposable organic compound according to the present invention, the first fluid containing the hardly decomposable organic compound and the second fluid containing ozone or hydrogen peroxide, While flowing in a laminar flow through the microchannel to which the photocatalyst is attached, ultraviolet rays are irradiated.
The generated OH radicals oxidize and decompose the hardly-decomposable organic compound of the first fluid based on molecular diffusion at the interface.
Therefore, the present invention exhibits the following effects.

<< First effect >>
First, accurate and precise data on the oxidation and decomposition of difficult-to-decompose organic compounds can be obtained. That is, in the present invention, the generated OH radicals oxidize and decompose persistent organic compounds based on molecular diffusion at the interface of laminar flow, that is, the interface with an extremely large surface area per unit volume, and acquire the data. To do.
Like this kind of prior art, that is, using the purifier's experimental machine, the mixing was performed in the turbulent flow as in the prior art where the data was acquired in batch mode, and the material order Data is not acquired under the situation where diffusion is performed with a long diffusion distance due to mass transfer.
Therefore, the intervention of external conditions other than the target oxidation and decomposition reaction is prevented, and only the target reaction proceeds purely without being influenced by the external conditions, and the target oxidation and decomposition are sufficiently performed. Controlled and prevented from mixing other substances such as by-products.
Thus, accurate data based on precise and quantitatively stable data and well-controlled and controlled reactions can be obtained for the oxidation and decomposition of difficult-to-decompose organic compounds.

<< Second effect >>
Secondly, accurate and precise data can be obtained in this way while being excellent in terms of efficiency and time. That is, in the present invention, the chemical reaction data is based on the technical idea of grasping in the micro reaction field on the micro order, and a microreactor is employed, and the organic compound is hardly decomposed by molecular diffusion at the interface of the laminar flow. Is oxidized and decomposed.
Therefore, compared to the conventional technology of this kind, that is, the conventional technology in which the purification device was used to acquire data in batch mode, the reaction efficiency was improved, and the total reaction time was several times, for example. The data is greatly shortened to about a minute, and data can be acquired efficiently and in a short time.
In addition, the amount of fluid, organic compound, ozone, hydrogen peroxide, photocatalyst, etc. to be used is very small as compared with the prior art, and the amount of ultraviolet irradiation is very small.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

《About drawing》
The microreactor for oxidative decomposition of a hardly decomposable organic compound of the present invention will be described in detail below based on the best mode for carrying out the invention shown in the drawings.
1, FIG. 2, FIG. 3 and FIG. 4 are used to explain the best mode for carrying out the present invention. 1 and 2 show a first example, FIG. 1A is a front cross-sectional explanatory view, and FIG. 1B is a perspective explanatory view. FIG. 2 (1) is an explanatory plan view, and FIG. 2 (2) is an enlarged view of a main part thereof.
FIG. 3 shows another example, and is a front cross-sectional explanatory view. (1) FIG. 3 shows a second example, (2) shows a third example, and (3) shows a fourth example. FIG. 4 is a graph of measurement data of oxidation and decomposition.

<< Outline of Micro Reactor 1 >>
First, with reference to FIG. 1, FIG. 2, FIG. 3, etc., the outline | summary of the microreactor 1 for oxidation and decomposition | disassembly of this hardly decomposable organic compound 2 is demonstrated.
The microreactor 1 is used to oxidize and decompose the hardly decomposable organic compound 2 contained in the first fluid 3 and thereby acquire the data.
First, the hardly decomposable organic compound 2 to be oxidized and decomposed is a paraffinic compound, an olefinic compound having a C = C bond, other chain hydrocarbons, an aromatic ring, that is, a phenyl group C ₆ H _5. It consists of a cyclic hydrocarbon with-and other cyclic hydrocarbons.
For example, monochlorobenzene CB, methyl isobutyl ketone MIBK, benzyl alcohol BA, isopropyl alcohol IPA, dimethylformamide DMF and the like, and environmental hormones such as dioxin Dioxin and bisphenol A (BPA) are typical.
Such an organic compound 2 is used as a solvent, for example, in a gas such as an exhaust gas discharged from an adhesion process, a coating process, or other chemical processing equipment, or a liquid in which such an exhaust gas is mixed with water. It is contained in the medium, that is, in the fluid. The first fluid 3 in the illustrated example is made of a liquid modeled as a sample.

The microreactor 1 is composed of a reactor including a microchannel 4 having a fine structure on the order of micrometers. The microchannel 4 has a channel width W of about 100 μm to 500 μm and a channel depth D of about 25 μm to 100 μm.
That is, the illustrated microreactor 1 is made of, for example, three stacked glass plates having a length of 80 mm, a width of 40 mm, and a thickness of about 2 mm, and plate holders 6 and 7 are densely stacked and covered on the upper and lower sides of the plate body 5. It consists of a fixed sandwich structure. Then, the micro flow path 4 is formed in the plate body 5, and the upper plate holder 6 is essentially transparent in the illustrated example because of the relationship with the ultraviolet irradiation, and the lower holder 7 is not transparent in the illustrated example. May be.
The micro flow path 4 is formed in a channel shape, and is linearly repetitively bent in the longitudinal direction of the plate body 5 and a plurality of times in the short direction, and is continuously reciprocally folded in a substantially zigzag shape. Is curved in a curved shape.
Although one set of plasma reactors 1 is shown in the illustrated example, a plurality of sets of plasma reactors 1 are stacked and used instead of the illustrated example, and a microscopic tube is connected between the microchannels 4. It is also conceivable that the total extension of the micro flow path 4 is ensured for a long time by connecting and linking with, for example.

<< Details of Microreactor 1 >>
The microchannel 4 of the microreactor 1 has an inlet portion 8 branched into two substantially Y-shaped channels (see FIG. 2), and the first fluid 3 is press-fitted from one inlet 9 and at the same time. The second fluid 11 is press-fitted from the other inlet 10.
The first fluid 3 contains a hardly decomposable organic compound 2. The second fluid 11 contains ozone O ₃ and hydrogen peroxide H ₂ O ₂ . That is, one or both of ozone O ₃ and hydrogen peroxide H ₂ O ₂ are contained.
Then, the first fluid 3 and the second fluid 11 are supplied from the respective supply units 12 and 13. The supply units 12 and 13 are each provided with a pump or the like, and the supply unit 12 supplies the first fluid 3 by pressure to one inlet 9 of the inlet 8 of the microchannel 4 via the fine tube 14. . The supply unit 13 pumps and supplies the second fluid 11 to the other inlet 10 of the inlet 8 of the microchannel 4 through the fine tube 14.

Further, an addition channel 15 is connected in the middle of the microchannel 4, and the addition channel 15 converts the second fluid 11 for replenishing the shortage to the second fluid 11 of the microchannel 4. It press-fits (see (2) in FIG. 1, (1) in FIG. 2).
That is, the supply unit 16 provided with a pump or the like supplies the supplementary second fluid 11 to the addition flow path 15 via the fine tube 14. Then, the second fluid 11 that has passed through the addition channel 15 is press-fitted into the second fluid 11 that flows in the microchannel 4. In the illustrated example, one such addition flow path 15 or the like is provided, but it is conceivable that a plurality of addition flow paths 15 are provided at intervals in accordance with the need for replenishment of the second fluid 11.
In the figure, reference numeral 17 denotes a filter (see FIG. 2 (1)), which removes in advance other substances and fine dust contained in the first fluid 3 so as not to hinder oxidation and decomposition. .
The first fluid 3 is supplied as an emulsion state in which the organic compound 1 is dispersed or turbid in water, for example, but can also be supplied in a uniformly saturated dissolved state or other states.
The second fluid 11 is supplied in a dissolved state in which ozone O ₃ and hydrogen peroxide H ₂ O ₂ are uniformly saturated with respect to water, for example, and in other states. Incidentally, the ozone O ₃ is generated by, for example, an ozonizer that converts oxygen O ₂ into ozone O ₃ by electric discharge or an ozone lamp having an ultraviolet wavelength having a peak value near 185 nm. To be supplied.
The microreactor 1 is roughly as described above.

<< About the photocatalyst 18 and the ultraviolet irradiation means 19 >>
Next, the photocatalyst 18 and the ultraviolet irradiation means 19 of the microreactor 1 will be described with reference to FIGS. A photocatalyst 18 is attached to a flow path forming surface 21 other than the ultraviolet irradiation surface 20 of the micro flow path 4.
That is, the microchannel 4 includes an upper surface, both side surfaces, and a bottom surface so as to form a channel for the first fluid 3 and the second fluid 11 therein. The upper surface (opened and may be sealed with the upper plate holder 6) becomes the ultraviolet irradiation surface 20 through which ultraviolet rays pass.
And the photocatalyst 18 is made to adhere to the flow-path formation surface 21 of both sides | surfaces and a bottom face except such an ultraviolet irradiation surface 20. FIG. The photocatalyst 18 is usually attached with titania, that is, titanium oxide TiO ₂ particles, together with metal fine particles and an adsorbent, for example, on the flow path forming surface 21 by a film-like support system such as coating or sintering.

By the way, the microchannel 4 of the example shown in FIG. 1 (1) has a shape in which two substantially semicircular portions are continuous in cross section, but various other shapes are also possible. For example, as shown in the example shown in FIG. 3 (1), the micro-channel 4 having a substantially arcuate shape with a shallow arc in the cross section, or as shown in the example shown in FIG. 3 (2) A microchannel 4 having a horizontally long rectangular shape is also conceivable.
3 is not only formed on one surface (upper surface) of the plate body 5 as in the example of FIG. 1 (1). The plate body 5 is formed on both surfaces (upper surface and lower surface). In this example, the micro-channels 4 on both sides are connected and coupled, and the ultraviolet irradiation means 19 are disposed opposite to each other.
In addition, about the example of each figure of FIG. 3, since another structure, a function, etc. are based on the place mentioned above about the example of FIG. 1, FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

The ultraviolet irradiation means 19 is disposed opposite to the microchannel 4. That is, the ultraviolet irradiating means 19 is slightly spaced from the plate body 5 on which the microchannel 4 is formed via the plate holder 6 (in the example of FIG. 3 (3), the transparent plate holder 7). However, they are arranged opposite to each other.
And the ultraviolet irradiation means 19 irradiates the micro flow path 4 with, for example, medium wavelength ultraviolet rays of 240 nm to 280 nm (eg, 254 nm). Moreover, what irradiates short wavelength ultraviolet rays of 160 nm-190 nm (for example, 185 nm) and long wavelength ultraviolet rays of 310 nm-390 nm (for example, 360 nm) can also be used.
Moreover, as a light source of such an ultraviolet irradiation means 19, in addition to a dedicated lamp such as a mercury lamp, a black light, an LED, or the like can be used.
The photocatalyst 18 and the ultraviolet irradiation means 19 are as described above.

<< Oxidation and decomposition of organic compound 2 >>
Next, referring to FIG. 1 (1), FIG. 2 (2), FIG. 3 (1), (2), (3), etc. Oxidation, decomposition, etc. will be described.
The first fluid 3 and the second fluid 11 supplied to the microchannel 4 are in contact with the interface 22 while forming a laminar flow. The first fluid 3 and the second fluid 11 flow in the microchannel 4 from the inlet portion 8 to the outlet portion 23 (see FIG. 1 (2) and FIG. 2 (1)). It flows as a laminar flow.
That is, the micro flow path 4 has a very small and narrow flow path width W, and the supplied first fluid 3 and second fluid 11 are also press-fitted with a pump or the like. The dimensionless number) is small and a laminar flow occurs. The first fluid 3 and the second fluid 11 that flow through the micro flow path 4 flow in a laminar flow so that the viscous force is dominant and there is no turbulence, and fluid particles do not enter and scramble so as to slide together.
And the 1st fluid 3 and the 2nd fluid 11 which flow as a laminar flow in this way are sent in parallel in the left-right parallel state, contacting at the interface 22 which is a boundary surface between phases.

The first fluid 3 and the second fluid 11 that flow in such a laminar flow are irradiated with ultraviolet rays from the ultraviolet irradiation means 19.
Then, OH radicals generated in the photocatalyst 18 and ozone O ₃ or hydrogen peroxide H ₂ O ₂ by ultraviolet irradiation are converted into the interface 24 between the photocatalyst 18 and the first fluid 3, and the second fluid 11 and the first fluid 3. At the interface 22, the organic compound 2 of the first fluid 3 is oxidized and decomposed based on molecular diffusion.
That is, the photocatalyst 18 attached to the flow path forming surface 21 of the micro flow path 4 generates OH radicals by ultraviolet irradiation through the first fluid 3 and the second fluid 11. In addition, ozone O ₃ and hydrogen peroxide H ₂ O _{2 of} the second fluid 11 also generate OH radicals by ultraviolet irradiation. The OH radicals generated in this way oxidize and decompose the organic compound 2 in the first fluid 3 based on molecular diffusion at the interface 22 and the interface 24.
At the interface 22 and interface 24 of the laminar flow, the OH radical is not a substance only by molecular diffusion and molecular movement between layers (instead of mass transfer in the flow path width W direction in the substance order as in the case of turbulent flow). It diffuses and oxidizes and decomposes the organic compound 2 in the first fluid 3.
The organic compound 2 is oxidized and decomposed in this way.

<About generation of OH radicals>
Here, the generation of the OH radical described above will be described in further detail. First, the generation of OH radicals by the photocatalyst 18 is as follows.
That is, when the photocatalyst 18 is irradiated with, for example, light energy (photon) hν of ultraviolet light of medium wavelength or long wavelength, an electron e ⁻ in the valence band in the outer electron region of the titanium oxide TiO ₂ surface is excited and jumped out. It moves to the conductor and becomes an electric current. → As a result, a hole hole ^{+ in} which the electron e ⁻ escapes and is lost is generated in the valence band. → See the following formula 1.

Hole hole ⁺ has a property of pulling out electrons e ⁻ from other substances that come into contact, for example, water H ₂ O that comes in contact with the electron vacancies, that is, has a strong oxidizing power.
On the other hand, water H ₂ O is ionized by irradiation with light energy to generate a hydroxide ion OH ^{− according} to the following formula 2.

Therefore, the hole hole ⁺ having a stronger oxidizing power extracts electrons e ⁻ from the hydroxide ions OH ⁻ of water H ₂ O. → Hydroxyl ion OH ⁻ deprived of electron e ⁻ generates a hydroxy radical (.OH), that is, an OH radical, according to the following formula 3.

Next, the generation of OH radicals by ozone O ₃ in the second fluid 11 is as follows (note that generation of OH radicals by hydrogen peroxide H ₂ O ₂ is similar to this).
That is, for example, when ozone O ₃ is irradiated with light energy (photon) hν of medium-wavelength ultraviolet light, → excited singlet oxygen atom O ( ¹ D), that is, an oxygen atom extremely rich in reactivity, is generated. → See the following formula 4.

The singlet oxygen atom O ( ¹ D) reacts with water H ₂ O in contact therewith, and generates a hydroxy radical (.OH), that is, an OH radical, according to the following formula 5.

<Oxidation and decomposition by OH radicals>
Further, the oxidation and decomposition by such OH radicals will be described in more detail.
Thus, the photocatalyst 18, ozone O ₃ , hydrogen peroxide H ₂ O ₂ and OH radicals generated by ultraviolet rays are extremely powerful oxidizing power, active power, and decomposing power as no other active oxygen species. → Strongly takes electrons from the nearby organic compound 2 and tries to stabilize it.
That is, the hardly decomposable organic compound 2 in the first fluid 3 in contact with the OH radical is deprived of electrons by such an OH radical, and → the carbon chain (for example, a single bond, a double bond, a triple bond, Aromatic ring bonds, etc.), organic bonds, molecular bonds themselves are cleaved, decomposed, broken, and then rapidly and strongly oxidized.
For example, in the case of ozone O ₃ , chain hydrocarbons of olefinic compounds that are relatively easy to oxidize and decompose have been limited to aldehydes via the ozonide stage, but are also difficult to oxidize and decompose. For the cyclic hydrocarbons with aromatic rings, etc., which were in the Oxine O _{3 state} , they were stopped at the glyoxal stage, but → OH radicals led to further smooth, rapid and powerful oxidation and decomposition. To do.
That is, by an OH radical having an extremely high oxidative activity for depriving electrons, for example, an aromatic ring is immediately opened, chained, aldehyded and carboxylated, and finally carbon dioxide CO ₂ and water It is immediately decomposed into H ₂ O and other low molecular weight compounds.
The OH radical has such excellent oxidizing power and decomposing power.

《Action etc.》
The microreactor 1 for oxidative decomposition of the hardly decomposable organic compound 2 of the present invention is configured as described above. Therefore, it becomes as follows.
(1) The micro flow path 4 of the micro reactor 1 has a fine structure, the flow path width W is about 100 μm to 500 μm, and the flow path depth D is about 25 μm to 100 μm. The ultraviolet irradiation means 19 is disposed oppositely, and the photocatalyst 18 is adhered to the flow path forming surface 21 other than the ultraviolet irradiation surface 20 (see FIGS. 1A and 1B and FIG. 3). reference).

(2) The inlet 8 of the microchannel 4 is branched in a substantially Y shape, and the first fluid 3 is press-fitted from one inlet 9 and the second fluid 11 is press-fitted from the other inlet 10. (See each figure in FIG. 2).
The first fluid 3 contains a hardly decomposable organic compound 2. For example, it contains paraffinic compounds, olefinic compounds, other chain hydrocarbons, cyclic hydrocarbons having aromatic rings, and other cyclic hydrocarbons.
The second fluid 11 contains ozone O ₃ and hydrogen peroxide H ₂ O ₂ . An addition flow path 15 is connected in the middle of the micro flow 4, and the second fluid 11 for replenishment is press-fitted and supplied to the second fluid 11 flowing through the micro flow path 4.

  (3) Since the Reynolds number is small, the first fluid 3 and the second fluid 11 supplied into the microchannel 4 flow in the microchannel 4 as laminar flows, respectively. The first fluid 3 and the second fluid 11 flow in parallel while being in contact with each other at the interface 22 of the laminar flow, and the first fluid 3 and the second fluid 11 are in contact with the photocatalyst 18 of the flow path forming surface 21 at the interface 24. However, they flow in parallel (see FIG. 2 (2)).

(4) Along with this, the microchannel 4 is irradiated with ultraviolet rays from the ultraviolet irradiation means 19 via the ultraviolet irradiation surface 20. Therefore, in the micro flow path 4, OH radicals are generated by the irradiated ultraviolet light and the photocatalyst 18 on the flow path forming surface 21, and the irradiated ultraviolet light and ozone O ₃ or hydrogen peroxide of the second fluid 11 are generated. OH radicals are generated in H ₂ O ₂ (see FIG. 1 (1) and FIG. 3).

(5) The OH radicals generated in this way have a strong oxidizing power and decomposing power, the interface 24 between the photocatalyst 18 and the first fluid 3, and the second fluid 11 and the first fluid 3. At the interface 22, the organic compound 2 of the first fluid 3 is oxidized and decomposed based on molecular diffusion (see FIG. 1 (1) and FIG. 3). For example, OH radicals generated by ozone O ₃ or hydrogen peroxide H ₂ O ₂ in the second fluid 11 and the organic compound 2 in the first fluid 3 are molecularly diffused between each other via the interface 22, thereby becoming organic. Compound 2 is oxidized and decomposed.
In other words, the hard-to-decompose organic compound 2 is cleaved by the OH radicals to break the carbon chain and the organic bond, and is quickly and reliably oxidized and decomposed into carbon dioxide gas CO ₂ and water H ₂ O.
In particular, by using the photocatalyst 18 in combination with ozone O ₃ and hydrogen peroxide H ₂ O ₂ , synergistic and powerful oxidation and decomposition are performed. That is, it excels in the light energy (photon) efficiency of the irradiated ultraviolet rays, and a large amount of OH radicals are generated at one time. The generated OH radicals cause oxidation and decomposition from both surfaces of the interface 22 and the interface 24. , All over.

  (6) In this way, the first fluid 3 is oxidized and decomposed in the hard-to-decompose organic compound 2 contained therein, and discharged together with the second fluid 11 from the outlet 23 of the microchannel 4 (FIG. 1). (See Fig. (2) and Fig. 2 (1)).

(7) Then, when the microreactor 1 for oxidative decomposition of the hardly decomposable organic compound 2 of the present invention is used, the following first and second cases are obtained.
First, in the present invention, the first fluid 2 and the second fluid 11 flow in a laminar flow in the microchannel 4 so as to slide regularly and regularly in parallel. → And the hardly decomposable organic compound 2 contained in the first fluid 3 is an interface 22 that is a contact surface between the first fluid 3 and the second fluid 11 or a contact surface between the first fluid 3 and the photocatalyst 18. The interface 24 is oxidized and decomposed by molecular diffusion of OH radicals generated on the second fluid 11 side and the photocatalyst 18 side.
→ And then, first, a. Since the microchannel 4 has a fine structure and is extremely small, the laminar interfaces 22 and 24 such as the first fluid 3 have a very large surface area per unit volume (unit volume). → In this way, the area 22/24 (specific interface area, specific surface area) per unit volume of the laminar flow of the first fluid 3 etc. is extremely large. → The reaction is directly and efficiently in a wide area. → Oxidation and decomposition of the hard-to-decompose organic compound 2 by OH radicals are widely and directly promoted.
→ Together with this, b. Such oxidation and decomposition of the hardly decomposable organic compound 2 by OH radicals are performed by molecular diffusion. → In other words, the first fluid 3 and the like are laminar, and the diffusion of the substance is (as in the case of turbulent flow, the mass transfer in the direction perpendicular to the flow direction and in the flow path width W direction, that is, This is not a substance movement in a substance order with a long diffusion distance in the flow path width W direction), but is performed only by molecular diffusion or molecular movement in which the diffusion distance in the flow path width W direction at the interfaces 22 and 24 is extremely short. . → As described above, since the reaction occurs at the interfaces 22 and 24, the oxidation and decomposition by OH radicals are efficiently and purely performed without being affected by other external conditions and other substances.

Owing to these a and b, oxidation and decomposition of the hardly decomposable organic compound 2 by OH radicals are carried out in a state that is quantitatively stable and the conditions are sufficiently controlled and controlled. Therefore, precise data with a small measurement width can be obtained for the oxidation and decomposition of the hardly decomposable organic compound 2.
For example, the flow rate of the first fluid 3 and the second fluid 11, the kind of the hard-to-decompose organic compound 2, the concentration, the oxidative degradation rate, the wavelength of ultraviolet rays, the irradiation time, the total length of the microchannel 4, and the photocatalyst 18 Accurate data can be obtained with respect to the relationship between the points such as the contents of configuration, the state of adhesion, the state of ozone O ₃ and hydrogen peroxide H ₂ O ₂ , temperature conditions, and the like.

Secondly, in the present invention, the microreactor 1 is employed for the first time in this technical field based on the concept of grasping chemical reaction data in a microscopic microscopic reaction field.
Since the hardly decomposable organic compound 2 is oxidized and decomposed by molecular diffusion at the laminar flow interfaces 22 and 24 formed in the microchannel 4, the reaction efficiency is improved and the reaction rate is increased.
For example, the micro flow path 4 of the microreactor 1 has a very fine structure, and the flow path width W is as small as about 100 μm to 500 μm. Therefore, the temperature gradient and pressure gradient from the interfaces 22 and 24 and the flow path forming surface 21 that govern the molecular diffusion in the flow path width W direction are relatively large with respect to the flow path width W. Because of its excellent conductivity, diffusion efficiency is improved and reaction time is shortened. In addition, the diffusion distance of molecular diffusion is remarkably reduced, and molecular diffusion is accelerated.
As a result, with respect to the oxidation and decomposition of the hardly decomposable organic compound 2 by OH radicals, the reaction efficiency is improved and the reaction rate is increased, so that data can be acquired efficiently and quickly.
Since the microreactor 1 is used, the first fluid 3 and the second fluid 11 used, the hardly-decomposable organic compound 2, ozone O ₃ , hydrogen peroxide H ₂ O _{2, and the} like may be used in an extremely small amount, and ultraviolet rays are used. Irradiation with ultraviolet rays by the irradiation means 19 is also minimal.

About test results
FIG. 4 shows measurement data obtained by subjecting the hardly decomposable organic compound 2 in the first fluid 3 to an oxidation and decomposition test using the microreactor 1 shown in FIGS.
That is, the first fluid 3 contains bisphenol A (BPA) as the organic compound 2, and the microfluidic channel 4 having a channel width W of 500 μm and a channel depth D of 100 μm is used. 11 contains ozone O ₃ , the flow rate of the first fluid 3 and the second fluid 11 is 0.1 ml / min, and the ultraviolet irradiation means 19 irradiates medium wavelength ultraviolet light at 254 nm. Tested.
As a result, the decomposition rate of the organic compound 2 is improved with the passage of time, and it is almost completely decomposed in about 40 minutes, and the total organic carbon amount TOC (Total Organic) measured using the TOC measuring instrument. Carbon) removal rate, that is, the removal rate of the carbon amount of the organic compound 2 in the liquid also improved with time, and was almost completely removed in about 40 minutes. Thus, oxidation and decomposition of the hardly decomposable organic compound 2 in the first fluid 3 were confirmed.

The microreactor for the oxidative decomposition of a hardly decomposable organic compound according to the present invention is used to explain the first example of the best mode for carrying out the invention. (1) FIG. 2) The figure is a perspective view. For the description of the first example of the best mode for carrying out the invention, FIG. 1A is a plan explanatory view, and FIG. 2B is an enlarged view of a main part thereof. FIG. 5 is a front sectional view for explaining another example of the best mode for carrying out the invention, wherein (1) FIG. 2 shows a second example, (2) FIG. 3 shows a third example, (3 The figure shows a fourth example. It is a graph of the measurement data of oxidation and decomposition | disassembly for the description of the other example of the best form for implementing the same invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Micro reactor 2 Organic compound 3 1st fluid 4 Micro flow path 5 Plate main body 6 Plate holder 7 Plate holder 8 Inlet part 9 One inlet 10 The other inlet 11 Second fluid 12 Supply part 13 Supply part 14 Fine tube 15 Additional flow Path 16 supply section 17 filter 18 photocatalyst 19 ultraviolet irradiation means 20 ultraviolet irradiation surface 21 flow path forming surface 22 interface 23 outlet section 24 interface D flow path depth W flow path width

Claims (5)

A microreactor used to oxidize and decompose a hardly decomposable organic compound contained in a fluid, comprising a micro flow path with a fine structure,
The microchannel is supplied with a first fluid containing the organic compound and a second fluid containing ozone or hydrogen peroxide, and an ultraviolet irradiating means is arranged oppositely, and a flow other than the ultraviolet irradiating surface is provided. A microreactor for oxidative decomposition of a hardly decomposable organic compound, characterized in that a photocatalyst is attached to a path forming surface. The microchannel has an inlet portion branched in a substantially Y shape, the first fluid is press-fitted from one inlet, and the second fluid is press-fitted from the other inlet,
In the microchannel, the first fluid and the second fluid are in contact with each other while forming a laminar flow,
OH radicals generated by the photocatalyst and the ozone or hydrogen peroxide by the ultraviolet irradiation by the ultraviolet irradiation means cause an interface between the photocatalyst and the first fluid, and the second fluid and the first fluid. 2. The microreactor for oxidative decomposition of a hardly decomposable organic compound according to claim 1, wherein the organic compound of the first fluid is oxidized and decomposed at the interface based on molecular diffusion.   3. The hardly decomposable organic material according to claim 2, wherein the microchannel has a channel width of about 100 μm to about 500 μm and a channel depth of about 25 μm to about 100 μm. A microreactor for oxidative degradation of compounds.   The organic compound is composed of paraffinic compounds, olefinic compounds, other chain hydrocarbons, cyclic hydrocarbons having an aromatic ring, and other cyclic hydrocarbons. A microreactor for oxidative decomposition of persistent organic compounds. An addition channel is connected in the middle of the microchannel, and the addition channel press-fits the second fluid for replenishment into the second fluid of the microchannel. A microreactor for oxidative decomposition of a hardly decomposable organic compound according to claim 3.

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