JP5605601B2 - Visible light responsive photocatalyst complex - Google Patents

Description

  The present invention relates to a visible light responsive photocatalyst complex in which visible light responsive photocatalysts including an organic photocatalyst and an adsorbent are stacked.

  In recent years, attempts have been made to apply photocatalysts to environmental purification. As such a photocatalyst, titanium oxide is mainly used. However, since titanium oxide exhibits photocatalytic activity by light in the ultraviolet region, only ultraviolet light corresponding to an energy density of 3% is used in sunlight.

  For this reason, the development of photocatalysts that can improve the efficiency of the photocatalytic reaction and that can utilize visible light of sunlight has been actively conducted.

  As for photocatalysts composed of organic compounds, polyparaphenylene and derivatives thereof have been reported (see Non-Patent Document 1). These are materials that are unstable under oxidation conditions, and have problems such as difficulty in use in the presence of oxygen, a gas (wet air) phase, and a liquid phase containing water.

In addition, it has been reported that a bilayer film composed of a p-type organic semiconductor such as phthalocyanine and an n-type organic semiconductor such as a perylene derivative works as a visible light responsive photocatalyst (Patent Document 1). However, when this is used for water treatment, the water treatment capacity for the amount of treated water is not necessarily high under practical conditions, so there is room for further improvement when water treatment is performed using the visible light responsive photocatalyst. there were.
International Publication No. 2006/115271 Pamphlet J. Chem. Soc. Faraday Trans., 93, 221 (1997)

  An object of the present invention is to provide a visible light responsive photocatalyst complex, a water treatment apparatus and a water treatment method using the visible light responsive photocatalyst complex.

  As a result of intensive studies to solve the above problems, the present inventors combined a predetermined adsorbent with an organic photocatalyst including a p-type organic semiconductor and an n-type organic semiconductor described in Patent Document 1. It was found that the water treatment capacity for the amount of water to be treated can be dramatically improved by stacking multiple items. As a result of further studies based on this finding, the present inventors have completed the present invention.

  That is, the present invention provides the following visible light responsive photocatalyst complex, water treatment apparatus, and water treatment method.

  Item 1. A visible light responsive photocatalyst complex formed by stacking a plurality of visible light responsive photocatalysts each having a layer containing a p-type organic semiconductor and an n-type organic semiconductor formed on an adsorbent layer.

  Item 2. Item 2. The visible light responsive photocatalyst composite according to Item 1, wherein the visible light responsive photocatalyst is formed by laminating a p-type organic semiconductor layer and an n-type organic semiconductor layer in this order on an adsorbent layer.

  Item 3. Item 3. The visible light responsive photocatalyst composite according to Item 2, wherein the visible light responsive photocatalyst has a p-type organic semiconductor layer thickness of 5 to 20 nm and an n-type organic semiconductor layer thickness of 5 to 20 nm.

  Item 4. Item 4. The visible light responsive photocatalyst complex according to any one of Items 1 to 3, wherein 10 to 50 visible light responsive photocatalysts are stacked.

  Item 5. The visible light responsive photocatalyst complex according to any one of claims 1 to 4, wherein the visible light responsive photocatalyst is stacked at an interval of 50 to 200 µm.

  Item 6. Item 6. The visible light responsive photocatalyst complex according to Item 5, wherein a spacer is disposed between the visible light responsive photocatalyst films.

  Item 7. Item 7. The visible light responsive photocatalyst complex according to any one of Items 1 to 6, wherein the material of the p-type organic semiconductor is at least one selected from the group consisting of a phthalocyanine derivative, a naphthalocyanine derivative, and a porphyrin derivative.

  Item 8. Item 8. The visible light responsive photocatalyst complex according to any one of Items 1 to 7, wherein the n-type organic semiconductor material is at least one selected from the group consisting of fullerenes, carbon nanotubes, perylene derivatives, and naphthalene derivatives.

  Item 9. The visible light responsive photocatalyst complex according to any one of claims 1 to 8, wherein the adsorbent is at least one selected from the group consisting of an ion exchange resin, cellulose gel, activated carbon, and a phenolic resin.

  Item 10. Item 10. A water treatment apparatus comprising the visible light responsive photocatalyst complex according to any one of Items 1 to 9 and a light source.

  Item 11. The water treatment apparatus according to claim 10, wherein the light source is natural light.

  Item 12. The water to be treated is caused to flow between the visible light responsive photocatalysts stacked while irradiating the visible light responsive photocatalyst complex according to any one of Items 1 to 9 with light from a light source, and is included in the water to be treated. Water treatment method for decomposing organic or inorganic substances.

  In the visible light responsive photocatalyst complex of the present invention, a plurality of visible light responsive photocatalysts in which a p-type organic semiconductor and an n-type organic semiconductor are stacked on an adsorbent layer are stacked. The contact area with the photocatalyst surface of treated water can be taken widely. Thereby, a large amount of water to be treated can be treated photocatalytically with a small light irradiation area.

  In addition, if a water treatment apparatus provided with the visible light responsive photocatalyst complex of the present invention and a light source is used, each visible light responsive photocatalyst film stacked while irradiating the visible light responsive photocatalyst complex with light is used. By flowing the water to be treated in between, the object to be treated contained in the water to be treated can be efficiently decomposed.

  Hereinafter, the present invention will be described in detail.

  The visible light responsive photocatalyst complex of the present invention is formed by stacking a plurality of visible light responsive photocatalysts. The visible light responsive photocatalyst is obtained by laminating a p-type organic semiconductor and an n-type organic semiconductor on an adsorbent layer.

  Specifically, in the visible light responsive photocatalyst, a layered adsorbent is in contact with a portion made of a p-type organic semiconductor (bulk layer) and a portion made of an n-type organic semiconductor (bulk layer) stacked thereon. The organic photocatalyst has a structure in which the adsorbent and the organic photocatalyst are bonded to or in contact with each other.

  In the organic photocatalyst, electron carriers and hole carriers are generated at the interface where the p-type organic semiconductor material and the n-type organic semiconductor material are in contact with each other by light irradiation, and unidirectional photoinduced electron transfer occurs. Carriers generated under this light irradiation are used for decomposition of an object to be treated (for example, an inorganic substance containing organic matter, nitrogen, sulfur, or phosphorus). Moreover, since the concentration of the object to be treated on the catalytic reaction surface can be increased by the adsorbent, the reaction efficiency on the organic photocatalyst can be dramatically increased.

  Examples of the p-type organic semiconductor having an oxidizing action include a macrocyclic ligand compound or a metal complex thereof. The macrocyclic ligand compound means a cyclic compound that contains an atom having an unpaired electron on the ring and can be a ligand for a metal atom, and the metal complex is the macrocyclic coordination. It means a metal complex consisting of a child and a metal atom. As an atom which has an unpaired electron, a nitrogen atom and an oxygen atom are mentioned, for example, A nitrogen atom is preferable. As a metal atom, each metal element of 1-15 group of a periodic table is mentioned, Preferably it is a 4-14 group metal element. In addition, the metal complex may be any metal as long as the metal atom and the macrocyclic ligand compound are 1: 1 (molar ratio) and form a planar four-coordinate complex.

  Specific examples of the macrocyclic ligand compound or the metal complex thereof include phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, and the like.

  A phthalocyanine derivative means a compound having a basic phthalocyanine skeleton. Specifically, for example, the following formula (1A) or (1B):

(In the formula, M ¹ represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table or an atomic group containing the metal atom, and a dotted line represents a coordinate bond)
The phthalocyanine derivative represented by these is mentioned.

Preferably among the Periodic Table 4-14 metals atom represented by M ^1, 7 group (in particular, Mn), Group 8 (Fe, Ru, Os) , 9 group (Co, Rh, Ir), 10 Group (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn).

Among the above, the phthalocyanine represented by the formula (1A), or the phthalocyanine derivative in which M ¹ is Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd, or Ru in the formula (1B) In particular, metal-free phthalocyanine, zinc phthalocyanine, or copper phthalocyanine is preferable from the viewpoint of activity in decomposition of the object to be treated. These compounds are either commercially available or can be easily produced by those skilled in the art.

  A naphthalocyanine derivative means a compound having a basic skeleton of naphthalocyanine. Specifically, for example, the following formula (2A) or (2B):

(In the formula, M ² represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table or an atomic group containing the metal atom, and a dotted line represents a coordinate bond)
The naphthalocyanine derivative represented by these is mentioned.

Of the metal atoms in groups 4 to 14 of the periodic table represented by M ² , group 7 (particularly Mn), group 8 (Fe, Ru, Os), group 9 (Co, Rh, Ir), group 10 are preferred. (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn).

Among the above, naphthalocyanine represented by the formula (2A), or naphthalocyanine in which M ² is Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd, or Ru in the formula (2B) Derivatives are preferable, and metal-free naphthalocyanine, zinc naphthalocyanine, or copper naphthalocyanine is particularly preferable from the viewpoint of activity in the decomposition of an object to be treated. These compounds are either commercially available or can be easily produced by those skilled in the art.

  A porphyrin derivative means a compound having a basic skeleton of porphyrin. Specifically, for example, the following formula (3A) or (3B):

(Wherein R ³ is the same or different, a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group, M ³ represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table, or a metal atom thereof. (Indicates the atomic group that contains it, and the dotted line shows the coordination bond
The porphyrin derivative represented by these is mentioned.

Here, examples of the alkyl group represented by R ³ include a C _1-20 linear or branched alkyl group, and a C _1-10 alkyl group is preferable. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like.

Moreover, as an aryl group shown by said R < ³ >, a monocyclic or bicyclic aryl group is mentioned, Specifically, a phenyl, a naphthyl, etc. are mentioned.

Examples of the heteroaryl group represented by R ³ include pyridyl and pyrazinyl.

Of the metal atoms of groups 4 to 14 of the periodic table represented by M ³ , group 7 (particularly Mn), group 8 (Fe, Ru, Os), group 9 (Co, Rh, Ir), group 10 are preferred. (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn).

Among the above, porphyrin represented by the formula (3A), or in the formula (3B), M ³ is Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd or Ru, R ³ is A porphyrin derivative which is a phenyl or hydrogen atom is preferable, and metal-free porphyrin, zinc porphyrin or copper porphyrin is particularly preferable from the viewpoint of activity in decomposition of the object to be treated. These compounds are either commercially available or can be easily produced by those skilled in the art.

Examples of the p-type organic semiconductor include the above-described macrocyclic ligand compounds or metal complexes thereof, preferably phthalocyanine derivatives, naphthalocyanine derivatives, and porphyrin derivatives. More preferably, the compound represented by Formula (1A), (1B), (2A), (2B), (3A), (3B) is mentioned. In particular, from the viewpoint of decomposition activity of organic substances and the like, metal-free phthalocyanine represented by formula (1A) and metal complexes of phthalocyanine (zinc phthalocyanine and copper phthalocyanine) in which M ¹ is represented by Zn and Cu in formula (1B), respectively preferable. The p-type organic semiconductor is available as a commercial product or can be easily manufactured by those skilled in the art.

  Examples of the n-type organic semiconductor include polycyclic aromatic compounds (which may be partially saturated). A polycyclic aromatic compound is a compound having a structure in which at least two aromatic rings are condensed, or a structure in which a plurality of aromatic rings are bonded via unsaturated bonds (double bonds, triple bonds, etc.). It means the compound etc. which have. In addition to the benzene ring and the like, the aromatic ring includes a heteroaromatic ring such as a pyrrole ring, an imidazole ring, a pyridine ring, and a quinoxaline ring (all of the rings may be partially saturated).

  The polycyclic aromatic compound may have various substituents within a range that does not adversely affect the present invention. Examples of the substituent include an electron withdrawing group, and specific examples include a carbonyl group, a sulfone group, and a sulfoxide group.

Specific examples of the polycyclic aromatic compound include fullerenes such as C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , and C ₈₄ ; carbon nanotubes; perylene derivatives; naphthalene derivatives. Among these, perylene derivatives, naphthalene derivatives, fullerenes (C _{60 and the} like) are preferably used, and perylene derivatives and fullerenes (C _{60 and the} like) are particularly preferable.

  A perylene derivative means a compound having a basic skeleton of perylene. Specifically, for example, the following formulas (4A) to (4C):

(Wherein R ¹ is the same or different and represents an alkyl group or an aryl group)
The perylene derivative represented by these is mentioned.

  A naphthalene derivative means a compound having a basic skeleton of naphthalene. Specifically, for example, the following formula (5A):

(Wherein R ² is the same or different and represents an alkyl group or an aryl group)
The naphthalene derivative represented by these is mentioned.

Here, examples of the alkyl group represented by R ¹ or R ² include a C _1-20 linear or branched alkyl group, and a C _1-10 alkyl group is preferable. Specific examples include methyl, ethyl, n-propyl, isopropyl, sec-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like.

Moreover, as an aryl group shown by said R < ¹ > or R < ² >, a monocyclic or bicyclic aryl group is mentioned, Specifically, a phenyl, a naphthyl, etc. are mentioned.

As the n-type organic semiconductor, one having a good pn junction relationship with the p-type organic semiconductor is used. Examples of the n-type organic semiconductor include the above-described polycyclic aromatic compounds (which may be partially saturated), and preferred are perylene derivatives, naphthalene derivatives, and fullerenes. More preferably, the compound represented by Formula (4A), (4B), (4C), (5A) is mentioned. In particular, from the viewpoint of efficient carrier generation, a perylene derivative (3,4,9,10-perylenetetracarboxyl-bisbenzimidazole) or a fullerene (C ₆₀ or the like) represented by the formula (4A) is preferably used. . The n-type organic semiconductor is available as a commercial product or can be easily manufactured by those skilled in the art.

  As the adsorbent used in the visible light responsive photocatalyst, a material having a high adsorption ability is used. Examples of such materials include ion exchange resins, cellulose gels, activated carbon, phenolic resins, and the like. In the present invention, since a plurality of visible light responsive photocatalysts are stacked and used, the adsorbent is preferably a material that transmits light. For example, those having a total light transmittance of about 90% / 100 μm are preferably used as the adsorbent. Examples of such materials include ion exchange resins based on hydrocarbons, fluorine carbides, silica, alumina, and the like. Among these, an ion exchange resin is particularly suitable for the adsorbent when the object to be treated is an amine or a carboxylic acid. When the object to be treated is an amine, a cation exchange resin is preferable. Specifically, a perfluorosulfonic acid or a salt thereof / PTFE (polytetrafluoroethylene) copolymer (for example, Nafion (registered trademark)), , Perfluorocarboxylic acid or a salt thereof / PTFE copolymer (for example, Flemion (registered trademark)), and the like. When the object to be treated is a carboxylic acid, an anion exchange resin is preferable.

  The visible light responsive photocatalyst is obtained by forming a layer containing a p-type organic semiconductor and an n-type organic semiconductor on an adsorbent layer.

  As a specific mode of the visible light responsive photocatalyst, a laminated (film) structure in which a p-type organic semiconductor and an n-type organic semiconductor are laminated on a thin-film adsorbent, and a p-type on a thin-film adsorbent. Examples include a structure in which a layer (film) made of a mixture of an organic semiconductor and an n-type organic semiconductor is formed. As a laminated structure, for example, a three-layer structure in which a p-type organic semiconductor and an n-type organic semiconductor are laminated in this order on a thinned adsorbent is preferable. This is because the oxidation reaction (decomposition reaction) of the object to be treated in the adsorbent is caused by the holes of the p-type organic semiconductor. Note that those described above can be used as the p-type organic semiconductor and the n-type organic semiconductor.

  When the visible light responsive photocatalyst has a laminated structure in which a p-type organic semiconductor and an n-type organic semiconductor are stacked on an adsorbent, the adsorbent layer, the p-type organic semiconductor layer, and the n-type organic semiconductor of the visible light responsive photocatalyst The film thickness of the layer can be set as appropriate.

  The thickness of the adsorbent is not particularly limited, but is, for example, about 1 to 200 μm, preferably about 10 to 100 μm. The thickness of the p-type organic semiconductor layer is not particularly limited, but is, for example, about 5 to 20 nm, preferably about 8 to 15 nm, and more preferably about 10 nm. The thickness of the n-type organic semiconductor layer is not particularly limited, but is, for example, about 5 to 20 nm, preferably about 8 to 15 nm, and more preferably about 10 nm.

  The grounds for setting the film thicknesses of the p-type organic semiconductor layer and the n-type organic semiconductor layer in the above ranges are as follows.

  For example, when irradiating light from the outside of a visible light responsive photocatalyst complex in which multiple visible light responsive photocatalysts are stacked, sufficient light is incident on the visible light responsive photocatalyst located inside (inside) Need to be done.

When only one visible light responsive photocatalyst is used, for example, when the p-type organic semiconductor is phthalocyanine and the n-type organic semiconductor is a perylene derivative, suitable thicknesses of the adsorbent, phthalocyanine, and perylene derivative are about 50 μm, The absorption efficiency of light (100 μW / cm ² ) of this visible light responsive photocatalyst reaches 99% (600 nm) or more. Therefore, when the visible light responsive photocatalyst having the thickness is stacked, even if light is irradiated from the outside, the light hardly reaches the inside, and the photocatalytic reaction does not occur inside. For example, when water containing 3 ppm of trimethylamine (TMA) is adsorbed at 0.2 ml / min with a Nafion membrane, 24 Nafion membranes (5 mm × 7 mm × 5 cm) must be stacked at 100 μm intervals (arranged in parallel). When the light reaches 100 μW / cm ² from the outside to the 10th sheet, the absorbance per sheet needs to be 0.2. The absorbance of 0.2 corresponds to a thickness of 10 nm of phthalocyanine and a thickness of 10 nm of the perylene derivative (600 nm). Therefore, it is necessary to reduce the film thickness to this extent. In this case, the photocatalytic efficiency is worse than that in the case of a visible light responsive photocatalyst where the film thickness of phthalocyanine is 50 nm and the film thickness of the perylene derivative is 200 nm. Since the actual (photocatalyst treatment amount / photocatalyst area) is small because adsorption is rate-determined more than the decomposition reaction, water treatment can actually be performed even if the phthalocyanine and perylene derivative film thicknesses are reduced to the above-mentioned levels.

  In addition, since the light absorbency of a normal organic semiconductor is 0.1 / 10 nm or more, even when using organic semiconductors other than a phthalocyanine and a perylene derivative, it calculates | requires by the same calculation. When using an organic semiconductor having a higher absorbance than this, it is necessary to reduce the number of stacked layers. In this case, the water treatment capacity (liter / minute) is reduced.

  The film thickness can be determined by the absorptiometry because it is proportional to the absorbance according to the Lambert-Beer law. This proportionality constant can be determined from the relationship between the film thickness and the absorbance determined using ellipsometry or an interference microscope.

  Although the manufacturing method of the visible light responsive type photocatalyst of this invention is demonstrated below, it is not limited to this.

  For example, when the visible light responsive photocatalyst is a three-layer film in which a p-type organic semiconductor and an n-type organic semiconductor are laminated on a thinned adsorbent, the p-type organic semiconductor and the n-type organic semiconductor are formed on the adsorbent film. Can be manufactured by sequentially laminating. In this case, the above-mentioned perfluorosulfonic acid or a salt thereof / PTFE copolymer, particularly Nafion (registered trademark) membrane is suitable as the material of the adsorbent. The obtained three-layer film can be used as a photocatalyst as it is.

  As a method of laminating the n-type organic semiconductor and the p-type organic semiconductor on the adsorbent, a known method can be adopted, for example, vacuum deposition method, sputtering method, electrochemical coating (electrodeposition), coating, etc. A method is mentioned. In order to uniformly coat the perylene derivative / phthalocyanine derivative system, vacuum deposition is preferred.

  Alternatively, a co-deposited layer may be formed by co-evaporating a p-type organic semiconductor and an n-type organic semiconductor on the adsorbent. Co-evaporation can be performed using a known method.

  For example, when the visible light responsive photocatalyst has a structure in which a layer (film) made of a mixture of a p-type organic semiconductor and an n-type organic semiconductor is formed on an adsorbent, the n-type organic semiconductor and It can manufacture by dripping on the adsorption material to the solution containing a p-type organic semiconductor, making it dry and forming a film.

  Typical examples of the p-type organic semiconductor include phthalocyanine derivatives, naphthalocyanine derivatives, and porphyrin derivatives. More preferably, the compound represented by Formula (1A), (1B), (2A), (2B), (3A), (3B) is mentioned. Furthermore, metal-free phthalocyanine, zinc phthalocyanine or copper phthalocyanine of the formula (1A) is preferred.

As the n-type organic semiconductor, one having a good pn junction relationship with the p-type organic semiconductor is used. Typical examples of the n-type organic semiconductor include perylene derivatives, naphthalene derivatives, and fullerenes. More preferably, the compound represented by Formula (4A), (4B), (4C), (5A) is mentioned. In particular, from the viewpoint of efficient carrier generation, a perylene derivative (3,4,9,10-perylenetetracarboxyl-bisbenzimidazole) or a fullerene (C ₆₀ or the like) represented by the formula (4A) is preferably used. .

  As a most suitable visible light responsive photocatalyst, a Nafion membrane, that is, a copolymer of perfluorosulfonic acid or a salt thereof / PTFE (polytetrafluoroethylene) (about 1 to 150 μm), metal-free phthalocyanine (about 5 to 20 nm) ) And perylene (about 5 to 20 nm) are stacked in this order.

  In addition to the above-mentioned n-type organic semiconductor and p-type organic semiconductor, silver, copper, or the like may be added to the visible light responsive photocatalyst as necessary in order to increase the activity of the photocatalyst.

  Fig.1 (a) is a schematic diagram which shows 1st Embodiment of the visible light response type photocatalyst composite_body | complex of this invention. As shown in FIG. 1A, a visible light responsive photocatalyst complex 1 according to the present invention is obtained by stacking a plurality of the visible light responsive photocatalysts 2 described above.

  The number of the visible light responsive photocatalysts 2 stacked is preferably set so that the light reaches the inside depending on the thickness of the p-type organic semiconductor and the n-type organic semiconductor to be stacked, the light intensity used, and the like. For example, when the thickness of each of the p-type organic semiconductor and the n-type organic semiconductor is about 10 nm, the number is about 10 to 50, preferably about 20 to 30.

  The distance d between the visible light responsive photocatalysts 2 is preferably set to about 50 to 200 μm. By setting the distance d between the membranes within this range, water can easily pass through the space between the membranes to adsorb the decomposition target in the water to be treated to the adsorbent and reduce the resistance of the water. The load applied to the water supply device can be reduced by lowering. A more preferable distance d is about 100 μm.

  In order to make the distance d between the visible light responsive photocatalysts 2 within the above range, the visible light responsive photocatalyst complex 1 has a spacer 3 between the films of the visible light responsive photocatalyst 2 as shown in FIG. Can be arranged. By inserting the spacer 3 between the films of the visible light responsive photocatalyst 2, the distance d between the visible light responsive photocatalysts 2 can be easily controlled. As a material of the spacer 3, a material that transmits light is preferable, and examples thereof include plastic, glass, and inorganic materials. The spacer 3 may have any shape as long as a gap d of about 50 to 200 μm is formed between the films of the visible light responsive photocatalyst 2 and a flow path can be secured, as shown in FIG. The present invention is not limited to the case where the square columnar spacers 3 are arranged at both ends of the film of the visible light responsive photocatalyst 2, and for example, plate-like spacers smaller in size than the visible light responsive photocatalyst 2 can be arranged between the films. Further, as the spacer 3, for example, a spherical shape, a cylindrical shape, a rod shape, a mesh shape or the like may be used.

  Here, the distance d between the visible light responsive photocatalysts 2 is set to about 50 to 200 μm using the spacer 3, but the distance d between the visible light responsive photocatalysts 2 can be within this range. Any method can be used. For example, the films of the visible light responsive photocatalyst 2 may be crossed two-dimensionally to form a honeycomb structure as shown in FIGS. 2 (a) and 2 (b), for example.

  Visible light responsive photocatalysts can be decomposed by contacting with organic substances contained in the aqueous phase or inorganic substances containing nitrogen, sulfur or phosphorus under light irradiation, and also for water. Since it is stable, the water containing the decomposition target can be efficiently treated. From this, it can apply to the water treatment apparatus which processes water using the visible light response type photocatalyst composite of the present invention.

  The water treatment apparatus of the present invention includes the above-described visible light responsive photocatalyst complex and a light source.

  Drawing 3 is a mimetic diagram showing one embodiment of the water treatment equipment of the present invention. As shown in FIG. 3, the water treatment device 4 includes a treated water storage tank 5 storing treated water, a flowing water pipe 6 through which treated water flows, and a treated water tank into which treated water is introduced. 7 and the visible light responsive photocatalyst complex 1 described above is filled in the middle of the flowing water pipe 6. In addition, a water supply device 8 for sending the water to be treated in the water to be treated storage tank 5 to the visible light responsive photocatalyst complex 1 in the flowing water pipe 6 is also provided, and a light source is provided near the visible light responsive photocatalyst complex 1. 9 is provided. In this apparatus, only one visible light responsive photocatalyst complex 1 is used, but two or more may be used.

  Examples of treated water include industrial circulating water, industrial wastewater, industrial wastewater, clean water, sewage, soil and groundwater, domestic wastewater, residual pesticide wastewater, bath, water tank, lake, pond, dam or pool. Water etc. are mentioned. These treated waters are not particularly limited in pH, hardness, etc., and can be treated efficiently. In particular, the pH is preferably about 7 to 11.

  Examples of the decomposition target contained in the water to be treated include organic substances and inorganic substances. Specifically, malodor-causing substances (trimethylamine, etc.), dust, microorganisms, viruses, sick house syndrome causative substances (formaldehyde, etc.), odor components (cigarette odor, pet odor, etc.), toxic substances (dioxins, PCBs, phenols, etc.) , Agricultural chemicals, ethylene gas, nitrogen compounds (ammonia, urea, etc.), sulfur compounds (mercaptans such as thiophenol; sulfides), and phosphorus compounds (organic phosphorus, etc.).

  In the present invention, since light having a wide range of wavelengths (wavelength of about 220 to 1200 nm) can be used, examples of the light source 9 include natural light (sunlight), fluorescent lamp, halogen lamp, high pressure mercury lamp, low pressure mercury lamp, One type of light source selected from a black light, an excimer laser, a deuterium lamp, a xenon lamp, an Hg—Zn—Pb lamp, or two types of light sources having different wavelength ranges can be used. In particular, the water treatment apparatus 4 of the present invention is extremely practical in that natural light (wavelength of 300 to 800 nm), particularly visible light (wavelength of 400 nm or more, particularly about 400 to 750 nm) can be used. The titanium oxide used in the conventional water treatment apparatus is extremely significant in consideration of the necessity of an ultraviolet light source indoors.

  In the water treatment device 4 of the present invention, the water to be treated in the treated water storage tank 5 is supplied to the flowing water pipe 6 by the water supply device 8, and the visible light responsive photocatalyst complex 1 is irradiated with light by the light source 9. (See arrow a in FIG. 1 (a)) If treated water is injected from one end face side (see arrow b in FIG. 1 (a)), the treated water passes between the films of the visible light responsive photocatalyst. In the meantime, the decomposition target contained in the for-treatment water is adsorbed by the adsorbent, and the photocatalyst is activated by light irradiation and decomposed by the generated carrier, thereby taking out purified water from the other end face side. be able to.

If such a water treatment apparatus 4 is used, the visible light responsive photocatalyst complex 1 is irradiated with light from the light source 9 while the visible light responsive photocatalyst complex 1 is exposed to the visible light responsive photocatalyst. The water to be treated is allowed to flow, and the organic or inorganic decomposition target contained in the water to be treated can be decomposed. The amount of water to flow is the inner diameter of the distribution pipe 6, the adsorbent of the visible light responsive photocatalyst, the thickness of the p-type organic semiconductor and the n-type organic semiconductor, the number of stacked visible light responsive photocatalysts, and the decomposition target contained in the water to be treated Usually, it is about 0.2 to ² ml / min · cm ² , although it varies depending on the amount of the liquid. At this time, it is preferable to supply air or oxygen-containing gas to the water to be treated (such as bubbling) because the decomposition reaction proceeds more efficiently.

FIG. 4A is a schematic diagram showing another embodiment of the water treatment apparatus of the present invention. In this water treatment device 4, a p-type organic semiconductor (metal-free phthalocyanine) (thickness 10 nm) and an n-type organic semiconductor (perylene derivative) (thickness 10 nm) are stacked on an adsorbent (Nafion film) having a thickness of 50 μm. 1 unit (1 cm × 1 m × 5 cm) in which four visible light responsive photocatalyst composites in which 24 visible light responsive photocatalysts are stacked at 100 μm intervals are arranged (a side view of FIG. 4B and FIG. 4C) 4 units (16 total visible light responsive photocatalyst composites) are incorporated. According to the water treatment device 4 of FIG. 4 (a), 10 ppm of trimethylamine can be removed to about 1/100 only by irradiating about 10 mW / cm ^{2 of} natural light for about 1 hour per day. If this water treatment apparatus 4 is used, it is possible to treat 1 ton of water to be treated per day.

  As a result, while irradiating the visible light responsive photocatalyst complex with light from a light source, the water to be treated is caused to flow between the stacked visible light responsive photocatalysts to decompose organic or inorganic substances contained in the water to be treated. A water treatment method is provided.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(1) As a photocatalytic material, 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (hereinafter referred to as “PTCBI”) which is an n-type semiconductor and metal-free phthalocyanine (hereinafter referred to as “H ₂ ”) which is a p-type semiconductor. Pc ”) was used. In this example, those purified by sublimation were used.

(2) Preparation of a triple layer film used as a photocatalyst was performed by vacuum-depositing two types of organic semiconductors on a commercially available Nafion film (manufactured by Dupont, Nafion 117, 50 μm thick). First, a two-layer film is formed by laminating H ₂ Pc with a thickness of about 10 nm on a Nafion film, and then a three-layer photocatalytic composite having a PTCBI layer with a thickness of about 10 nm on the H ₂ Pc layer. Got the body. This photocatalyst complex was cut into 6 mm × 50 mm, 24 sheets were stacked, and a 4 mm × 20 mm plastic plate (thickness 100 μm) was inserted as a spacer between each film to obtain a photocatalyst complex. And what put this photocatalyst complex into the heat contraction tube (Hishi tube (UGEB3050) by Mitsubishi Resin Co., Ltd.) and was heat-shrinked was introduce | transduced in the following water treatment apparatuses.
The film thickness was measured by an absorption spectrum method and an optical interference method.

(3) A schematic diagram of the water treatment apparatus is shown in FIG. In this water treatment apparatus, two commercially available Tygon tubes (manufactured by Saint-Gobain Co., Ltd., TYGON (registered trademark) FLEXIBLE PLASTIC TUBINING (R-3603)) are connected to the pump (the length of each tube is 1 m). The heat shrinkable tube obtained in (2) is attached to the tip of one tube, and the other tube is inserted into a tank (hereinafter referred to as TMA tank) containing trimethylamine (hereinafter referred to as TMA tank). This TMA tank is sealed with a rubber plug through a glass tube so that the concentration of TMA does not change, and is filled with argon gas (Tedlar bag with a mini valve (CEK-1) manufactured by GL Sciences Inc.) Is attached, and the pressure in the TMA tank as the supply water is kept at atmospheric pressure while preventing the load on the water supply device and the decrease due to the volatilization of TMA. This Tedlar back was used for the purpose of guaranteeing the accuracy of data, and is not necessarily a necessary condition in a practical water treatment system. The water to be treated is pulled up from the TMA tank by 0.2 ml per minute by a pump and flows between the membranes of the photocatalyst complex (TMA concentration: 3.08 ppm). And 1 microliter of water which passed between the films | membranes of a photocatalyst composite_body | complex was extract | collected using the syringe, and TMA density | concentration was calculated | required by gas chromatography (GC-2014). The experiment was performed for 100 hours. No light was irradiated for the first 50 hours, and visible light was irradiated with a halogen lamp for 50 hours of the second half (intensity: 100 mW / cm ² ). The result is shown in FIG.

  As a comparative example, the Nafion film was cut into 6 mm × 50 mm, 24 sheets were stacked, and the same 4 mm × 20 mm plastic plate as in Example 1 (2) was inserted as a spacer between each film. The TMA concentration was measured under the same conditions as in 1 (3). The result is also shown in FIG.

  From the results shown in FIG. 6, although TMA is initially adsorbed by the adsorption ability of the Nafion film of the photocatalyst complex without irradiating light, the adsorption ability of the Nafion film has dropped during 24 hours, and the TMA concentration is sufficient. It was found that TMA was removed by not being lowered, and by subsequent irradiation with light.

  In addition, looking at the results of only the Nafion film (□) as a comparative example, TMA is initially adsorbed by the Nafion film, but the adsorption ability does not recover even after irradiation with light, and the TMA concentration does not become sufficiently low. I understand. From this, it can be seen that the adsorption ability deteriorates in a short time only with the Nafion film.

  From these results, it is shown that in the photocatalyst complex, TMA adsorbed on the Nafion film is decomposed by the organic photocatalyst activated by light irradiation, thereby regenerating the adsorption ability of the Nafion film.

Incidentally, stacking the PTCBI layer on Nafion membrane, except for forming the _H 2 Pc layer on PTCBI layer in Example 1 (1) and (2) using the photocatalyst composite was produced in the same manner as, performed When the TMA concentration was measured under the same conditions as in Example 1 (3), the TMA removal rate after light irradiation was worse than that of the photocatalyst composite in which the H ₂ Pc layer and the PTCBI layer were laminated in this order on the Nafion film. (Not shown).

Example 2
A heat-shrinkable tube containing a photocatalyst complex prepared in the same manner as in Example 1 (1) and (2) was introduced into the water treatment apparatus of FIG. The TMA concentration in the TMA tank was 3 ppm, and the water to be treated was passed between the photocatalyst membranes at a flow rate of 0.2 ml / min as in Example 1 (3). The experiment was carried out for 47 days, during which time visible light was irradiated once a day with a halogen lamp for 1 hour (intensity 10 mW / cm ² ). Water that has passed between the membranes of the photocatalyst complex without irradiation with light every week up to 3 weeks (21st day) after the start of the experiment, and 2 to 3 times a week thereafter, 1 μl of water that passed between the membranes of the photocatalyst complex 1 hour after the light irradiation was collected with a syringe, and the TMA concentration was determined by gas chromatography (GC-2014). The result is shown in FIG.

From the results shown in FIG. 7, in all cases, TMA was almost removed on the first day (day 0), and 0.0 ppm of TMA was detected. In the case of only the Nafion membrane (without H ₂ PC / PTCBI), an increase in TMA concentration was observed from the 18th day, and 2.1 ppm of TMA was detected on the 36th day. When the photocatalyst complex was used, the TMA concentration increased from the 27th day, but the amount of TMA detected decreased immediately after 1 hour of visible light irradiation, and only 0.1 ppm of TMA was detected even on the 40th day. Was not. Thereafter, the TMA concentration increased as the number of days increased. However, a partial recovery of the ability to remove TMA by 1 hour of visible light irradiation was observed even on the 47th day from the start of the experiment. If the complete removal ability of TMA is defined as a TMA concentration of 0.2 ppm or less, it can be said that the life of the complete removal ability of TMA is extended from 20 days to 40 days by laminating the photocatalyst on the adsorbent.

(A) is a schematic diagram showing one embodiment of the visible light responsive photocatalyst complex of the present invention, and (b) is a schematic diagram showing another embodiment of the visible light responsive photocatalyst complex of the present invention ( Perspective view). (A) And (b) is a schematic diagram (sectional drawing) which shows the example of the crossing state of a visible light response type photocatalyst film. It is a mimetic diagram showing one embodiment of the water treatment equipment of the present invention. (A) is a schematic diagram which shows another embodiment of the water treatment apparatus of this invention, (b) and (c) are visible light response type photocatalyst composites used for the water treatment apparatus of (a). They are a side view and a sectional view, respectively. 1 is a schematic diagram of a water treatment device used in Example 1. FIG. It is a graph which shows a time-dependent change (100 hours) of the triethylamine density | concentration after passing a photocatalyst composite_body | complex. It is a graph which shows a time-dependent change (47 days) of the triethylamine density | concentration after passing a photocatalyst composite_body | complex.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Visible light response type photocatalyst complex 2 Visible light response type photocatalyst 3 Spacer 4 Water treatment device 5 Water to be treated storage tank 6 Flow channel 7 Treatment water tank 8 Water supply device 9 Light source

Claims (7)

The adsorbent layer, a p-type organic semiconductor layer and an n-type organic semiconductor layer is visible light responsive photocatalyst complex composed by stacking 10 to 50 sheets of the visible-light-responsive photocatalyst, which are laminated in this order The p-type organic semiconductor layer is a phthalocyanine derivative with a thickness of 5 to 20 nm, and the n-type organic semiconductor layer is a perylene derivative with a thickness of 5 to 20 nm. . The visible light responsive photocatalyst complex according to claim 1, wherein the visible light responsive photocatalyst is stacked at an interval of 50 to 200 μm. The visible light responsive photocatalyst complex according to claim 2 , wherein a spacer is disposed between the visible light responsive photocatalyst films. The visible light responsive photocatalyst complex according to any one of claims 1 to 3 , wherein the adsorbent is at least one selected from the group consisting of an ion exchange resin, cellulose gel, activated carbon, and a phenolic resin. A visible light responsive photocatalyst complex according to any one of claims 1 to 4 and a light source , wherein the visible light responsive photocatalyst complex is irradiated with light from the film thickness direction with the light source, Water treatment device that flows in a direction parallel to the membrane . The water treatment apparatus according to claim 5 , wherein the light source is natural light. The visible light responsive photocatalyst composite according to any one of claims 1-4, while irradiating light from a thickness direction of the light source, the water to be treated film between the visible light responsive photocatalyst that are stacked A water treatment method for decomposing organic matter or inorganic matter contained in water to be treated by flowing in parallel directions .

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