JP2013103174A - Hydrophobic adsorbent and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a useful hydrophobic adsorbent capable of maintaining adsorbing performance without closing pores of a porous body, having excellent repeated desorbing performance and exhibiting excellent adsorbing performance in a highly humid condition.SOLUTION: The hydrophobic adsorbent is obtained by attaching hydrophobic metal oxide particles subjected to surface modification with a silicon compound indicated by a formula (1) to the porous body. The formula (1) is R-Si(CH)(-X), wherein R indicates a 1-18C alkyl group, a 2-4C alkenyl group, a 2-3C alkynyl group or a 6-8C aryl group, X indicates a 1-3C alkoxy group, C indicates a carbon atom, H indicates a hydrogen atom, Si indicates a silicon atom and n indicates 0-2.

Description

The present invention has a practicality that the surface of the porous body is hydrophobized, but the adsorption capacity can be maintained without blocking the pores of the porous body, has excellent repeated desorption performance, and under high humidity conditions The present invention relates to a hydrophobized adsorbent exhibiting excellent adsorption ability, a method for producing the same, and a solvent recovery apparatus using the adsorbent.

As a representative adsorbent, activated carbon is inexpensive and is used in large quantities, and its shape is processed into various forms such as fiber, granule, pellet, honeycomb, and paper. The surface of the activated carbon is generally said to be hydrophobic, and exhibits extremely high adsorption performance for organic solvents with low polarity. However, under high-humidity conditions where water coexists, the original performance cannot be achieved because water coexists. One of the causes is said to be that there are hydrophilic groups such as OH groups and carboxyl groups generated by activation during the production process on the activated carbon surface. In such activated carbon, when moisture in the air is present, the surface of the activated carbon is made more hydrophilic by adsorbing water molecules during use, and the adsorption of the target hydrophobic organic solvent is hindered. There was a problem that it decreased in a short period of time.
In view of the above background, there is a demand for the development of a new technology that can efficiently remove contaminants in organic solvents by surface modification.
As a method for making the surface of activated carbon or activated carbon fiber hydrophobic with respect to the above problem, a method of heating an activated carbon material in an inert atmosphere or heating in a hydrogen stream is known. (For example, Non-Patent Document 1). However, since such a method heats the activated carbon material at a high temperature of 600 ° C. or higher, a large amount of energy is required, and the apparatus is also required to have heat resistance, resulting in poor economic efficiency. Further, there is a problem that OH groups and the like are generated again during use, and the hydrophobicity is lowered.
On the other hand, in view of the above background, the inventors synthesize a silicon hydrophobizing agent having an alkyl chain and tried to attach this to activated carbon. There was a problem that performance was impaired.

Shinzo Kanno, “Surface modification and adsorption characteristics of carbon-based adsorbents”, Surface, Vol. 29, No. 6, 448 (1991)

To obtain a hydrophobized adsorbent that exhibits excellent adsorbability under high humidity conditions without blocking the pores of the adsorbent, first select the size of metal oxide particles suitable for the porous material to be applied. It is to be. Since the adsorbent has a different pore structure depending on the material, when an unsuitable metal oxide particle is selected, it becomes a cause of pore clogging. Next, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 3 carbon atoms, or an aryl group having 6 to 8 carbon atoms is selected as R for realizing hydrophobicity. These alkyl long chains form a barrier against water such as a network structure on the surface of the adsorption site, and an optimal functional group is selected according to the molecular diameter of the gas species to be adsorbed. Finally, it is possible to solve the problem by attaching optimal hydrophobic metal oxide particles to the porous body.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have reached the present invention.
That is, the present invention is a hydrophobized adsorbent characterized in that hydrophobic metal oxide particles surface-modified with a silicon compound represented by the formula (1) are attached to a porous body.
R—Si (CH ₃ ) _n (—X) _3-n (1)
Where R is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 3 carbon atoms or an aryl group having 6 to 8 carbon atoms, and X is an alkoxy group having 1 to 3 carbon atoms. , C represents a carbon atom, H represents a hydrogen atom, Si represents a silicon atom, and n represents 0 to 2.

Further, the present invention is the method for producing the hydrophobic adsorbent by dissolving (dispersing) a water-soluble organic solvent in the hydrophobic metal oxide particles, immersing the porous body and drying it.

Moreover, this invention is a solvent collection | recovery apparatus using the said hydrophobization adsorbent.

The hydrophobized adsorbent produced in the present invention exhibits hydrophobicity without blocking the pores of the porous body, and can exhibit its original adsorption performance without simultaneously adsorbing moisture. It is effective for applications such as adsorption, recovery, and separation. Moreover, if the manufacturing method for obtaining the hydrophobization adsorbent of this invention is taken, it can aim at a pore characteristic and target gas, and it becomes possible to improve repetition durability.

In the present invention, the hydrophobic metal oxide particles are surface-modified with a silicon compound represented by the formula (1).
R—Si (CH ₃ ) _n (—X) _3-n (1)
Where R is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 3 carbon atoms or an aryl group having 6 to 8 carbon atoms, and X is an alkoxy group having 1 to 3 carbon atoms. , C represents a carbon atom, H represents a hydrogen atom, Si represents a silicon atom, and n represents 0 to 2.

In the formula (1), the alkyl group having 1 to 18 carbon atoms represented by R includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, n-hexyl group, 2- Examples include an ethylhexyl group, an n-octyl group, a dodecyl group, and an n-octadecyl group.
Examples of the alkenyl group having 2 to 4 carbon atoms include a vinyl group, an allyl group, and a butenyl group.
Examples of the alkynyl group having 2 to 3 carbon atoms include an ethynyl group and a propargyl group.
Examples of the aryl group having 6 to 8 carbon atoms include a phenyl group, a benzyl group, and an ethylphenyl group.
Of these R, in view of cost, it is preferably an alkyl group having 1 to 8 carbon atoms.

In the formula (1), examples of the alkoxy group having 1 to 3 carbon atoms of X include a methoxy group, an ethoxy group, and an n-propoxy group.
Of these, considering cost, a methoxy group and an ethoxy group are preferable.

Specific examples of the silicon compound represented by the above formula (1) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, Isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, tert-butyltrimethoxysilane, tert-butyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxy Silane, n-octyltrimethoxysilane, n-octyltriethoxysilane, isooctyltrimethoxysilane, isooctyltriethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysila N-octadecyltrimethoxysilane, n-octadecyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriethoxysilane, Phenyltriethoxysilane, 4-butylphenyltrimethoxysilane, 4-butylphenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltri Ethoxysilane, ethynyltrimethoxysilane, ethynyltriethoxysilane, propargyltrimethoxysilane, propargyltriethoxysilane, etc. Functional silanes;
Dimethyldimethoxysilane, dimethyldiethoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, didodecyldimethoxysilane, didodecyldiethoxysilane, methyloctyldimethoxysilane, methyloctyldiethoxysilane, dodecyl Bifunctional silanes such as methyldimethoxysilane, methyloctyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane;
Monofunctional silanes such as triethylmethoxysilane, triethylethoxysilane, tripropylmethoxysilane, tripropylethoxysilane, triphenylmethoxysilane, triphenylethoxysilane, diphenylmethylmethoxysilane, diphenylmethylethoxysilane, and the like can be given.

Examples of the metal oxide of the metal oxide particles include silica, titania, alumina, and zirconia.
As for the magnitude | size of a metal oxide particle, 5-200 nm is preferable, More preferably, it is 5-150 nm, More preferably, it is 10-100 nm.
The metal oxide particles are preferably in the form of metal oxide sol, more preferably silica sol, and particularly preferably organosilica sol.
The organosol is a colloidal solution in which colloidal silica whose surface has been modified at the nano level is stably dispersed in an organic solvent, and can be dispersed in various organic solvents such as alcohol, ketone, ether, and toluene.
Specifically, organosilica sol (methanol silica sol, IPA-ST, IPA-ST, IPA-ST-UP, IPA-ST-ZL, EG-ST, NPC-ST-30, DMAC-ST, manufactured by Nissan Chemical Industries, Ltd. MEK-ST, MIBK-ST, PMA-ST and PGM-ST) and high-purity organosilica sol (PL-1-IPA, PL-2L-PGME and PL-2L-MEK) manufactured by Fuso Chemical Industry Co., Ltd. .
These may be used not only alone but also plurally.

Hydrophobic metal oxide particles can be obtained by surface-modifying the metal oxide particles with a silicon compound represented by the above formula (1).
That is, it can be obtained by a method in which the metal oxide particles and the silicon compound are heated and reacted in an organic solvent containing a small amount of water or water to chemically bond the silicon compound to the surface of the metal oxide particles.

As a solvent in the case of reacting the metal compound represented by the above formula (1) with the metal oxide particles, alcohol solvents: methanol, ethanol, isopropanol, n-butanol, t-butanol, pentanol, ethylene glycol, propylene Glycol and 1,4-butanediol, etc., ether solvents: diethyl ether, tetrahydrofuran, dioxane, etc., ketone solvents: acetone, methyl ethyl ketone, etc., aprotic solvents: dimethyl sulfoxide, N, N-dimethylformamide, etc. These mixed solvents are exemplified.
Among these, alcohol solvents are preferable, and these solvents can be used alone or in combination of two or more.

The density | concentration of the raw material metal oxide particle with respect to a solvent is 1-50 mass%, Preferably it is 1-30 mass%.

The amount of the silicon compound relative to the metal oxide particles is preferably 0.01 to 10.0 mmol, particularly preferably 2.0 to 5.0 mmol, relative to 1 g of the metal oxide particles.

Although the temperature at the time of adding a silicon compound is not limited, the boiling point is preferable from normal temperature (about 20 degreeC).
Although the reaction temperature is not limited, the boiling point is preferably from room temperature (about 20 ° C.).
Although the reaction time is not limited, it is preferably 10 minutes to 48 hours, particularly preferably 6 hours to 24 hours.

The hydrophobic metal oxide particles may contain a diluting solvent in order to improve workability. The diluent solvent is not limited as long as it does not react with the modified metal oxide sol of the present invention and dissolves and / or disperses them. For example, ether solvents (tetrahydrofuran, dioxane, etc.), alcohol solvents Solvents (methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) and aprotic solvents (N, N-dimethylformamide) N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and the like) and water.

  When the diluent solvent is contained, the content of the diluent solvent is, for example, from 0.01 to 15 mass fraction% (preferably 0.05 to 10 mass%) of the modified metal oxide sol of the present invention based on the total solvent. Mass fraction%, particularly preferably 0.1 to 7.5 mass fraction%).

The hydrophobized adsorbent of the present invention can be obtained by attaching hydrophobic metal oxide particles to a porous body.
The porous body used as the raw material is not particularly limited as long as it has a large number of fine pores, and preferred examples include activated carbon, zeolite, alumina, and silica.

  As the activated carbon, various activated carbons such as graphite, mineral materials (coal such as lignite and bituminous coal, petroleum or coal pitch), plant materials (wood, fruit shells (coconut shells, etc.)), animals, etc. Examples thereof include activated carbon made from a raw material (animal bone, skin, etc.), a polymer material (polyacrylonitrile (PAN), phenolic resin, cellulose, regenerated cellulose, etc.). Activated carbon can be obtained by carbonizing or infusibilizing these raw materials as necessary, and then performing an activation treatment. The carbonization method, the infusibilization method, and the activation method are not particularly limited, and conventional methods can be used. For example, activation is performed by a gas activation method in which a carbon raw material (or a carbide or infusible product thereof) is heat-treated at about 500 to 1000 ° C. in an activation gas (water vapor, carbon dioxide, etc.), a carbon raw material (or a carbide or infusible product thereof). ) May be mixed with an activator (phosphoric acid, zinc chloride, potassium hydroxide, sodium hydroxide, etc.), and may be performed by a chemical activation method in which heat treatment is performed at about 300 to 800 ° C.

Among the activated carbons, plant-based activated carbons such as coconut shell activated carbon, mineral-based activated carbons using coal as a raw material, and polymer-based activated carbons such as pitch-based activated carbon, PAN-based activated carbon, cellulose-based activated carbon, and phenol-based activated carbon are preferable. Activated carbon can be used individually or in combination of 2 or more types.

The shape of the porous body is not particularly limited, and may be a fibrous shape, a pellet shape, a granular shape, a honeycomb shape, or a paper shape.

The specific surface area of the porous body, for example, 350~2500m ² / g, preferably 500~2000m ² / g, more preferably about 700~1900m ² / g.

The porous body may be used alone, or may be used as a molded body composed of the porous body and a binder component (or forming component).
As the binder component, it is sufficient that the porous body can be shaped or formed into an appropriate shape (eg, granular, sheet, honeycomb, etc.). For example, inorganic clay minerals such as sepiolite, zeolite, attapulgite, talc, montmorillonite, phenol In addition to binders such as resin and pitch resin, fiber components and the like are also included. These binder components can be used alone or in combination of two or more thereof, and if necessary, a binder and a fiber component may be used in combination.

Among the binder components, the fiber component includes synthetic fiber (polyester fiber (polyethylene terephthalate fiber etc.), polyamide fiber, polycarbonate fiber, polyimide fiber, polyether ether ketone fiber, polyether sulfone fiber, polyphenylene sulfide fiber, polyacetal fiber, Phenol resin fiber, polyarylate fiber, liquid crystal polymer fiber, etc.), semi-synthetic fiber (cellulose ester fiber such as cellulose acetate), natural fiber (eg cellulose fiber, cotton, hemp, rock wool, wool fiber, etc.), inorganic fiber (Carbon fiber, silicon carbide fiber, glass fiber, silica-alumina fiber, etc.). These fiber components can be used alone or in combination of two or more. Among the above fiber components, cellulose fibers, cellulose ester fibers, mixed fibers containing these cellulose fibers, pulp, and the like are preferable. The fiber component may be beaten if necessary.

  The molded body using the binder component together with the porous body is usually molded into a fibrous shape, a sheet shape, a honeycomb shape, etc. using (i) a porous body, a binder, and, if necessary, a fiber component, A pelletized molded body, and (ii) a molded body molded into a sheet shape by means such as paper making using a porous body, a fiber component, and, if necessary, a binder are included.

  In the molded body containing the binder component, the ratio of the binder component is, for example, 0.1 to 500 parts by weight, preferably 1 to 400 parts by weight, and more preferably 5 to 300 parts by weight with respect to 100 parts by weight of the porous body. It may be about a part. For example, in a porous body having a papermaking structure in which a porous body is made with a fiber component, the ratio of the binder component (fiber component) is, for example, 10 to 500 parts by weight, preferably 100 parts by weight of the porous body. May be about 50 to 450 parts by mass, more preferably about 100 to 350 parts by mass.

The shape of such a porous body-containing molded body is not particularly limited, and may be granular (powder or pellet form), fibrous form, sheet form, or honeycomb form.

  The amount of the hydrophobic metal oxide particles to be added is preferably 0.01 to 20% by mass, particularly preferably 1 to 3% by mass, with respect to the porous body.

Examples of the method of attaching the hydrophobic metal oxide particles to the porous body include a method in which the hydrophobic metal oxide particles are dissolved (dispersed) by adding a water-soluble organic solvent, and the porous body is dipped and dried. It is done.
As the water-soluble organic solvent, alcohols are preferable, and methanol and ethanol are particularly preferable.
The temperature is usually about 25 to 150 ° C., and the time is 1 to 6 hours.

In the present invention, the average particle diameter of the primary particles of the hydrophobic metal oxide particles is nanometer size, for example, about 1 to 500 nm, preferably 5 to 250 nm, more preferably 7 to 100 nm (for example, 10 to 70 nm). In general, it may be about 5 to 75 nm (for example, 10 to 60 nm). If the average particle size of the primary particles is too small, handling may be difficult, and if the average particle size is too large, the adsorptive capacity decreases.
The average particle diameter of the secondary particles of the hydrophobic metal oxide particles is, for example, about 0.001 to 100 μm, preferably about 0.005 to 30 μm, and more preferably about 0.007 to 20 μm. If the average diameter of the hydrophobizing material is too small or too large, the adsorptive capacity decreases.
The average particle diameter of the primary particles of the hydrophobic metal oxide particles was determined by measuring the size of 100 primary particles based on an image taken with a transmission electron microscope (TEM, HITACHI H-7100). Can be calculated by averaging. The average particle diameter of the hydrophobic metal oxide particles can be calculated by measuring the size of 10 hydrophobic metal oxide particles based on an optical microscope and averaging the measured values.
The hydrophobized adsorbent of the present invention has a porous structure and has pores and pore volumes capable of adsorbing organic solvents such as methylene chloride and toluene. The specific surface area of the hydrophobic adsorbent, for example, specific surface area, for example, 300~2400m ² / g, preferably 400~1900m ² / g, more preferably about 600~1800m ² / g.
If the specific surface area or pore volume is too small, the adsorption amount of the organic solvent cannot be increased, and if the specific surface area or pore volume is too large, the preparation of the hydrophobized adsorbent may be difficult. If the pore size is too small, it is difficult to form an adsorption site for the organic solvent, and if it is too large, various components are adsorbed and the selective adsorption of the organic solvent is often impaired.
The specific surface area can be measured by a nitrogen gas adsorption method for a sample that has been vacuum degassed at 150 ° C. using an analyzer (ASAP-2400 manufactured by Micromeritics), and the specific surface area can be calculated by the BET method.

The hydrophobized adsorbent of the present invention is suitably used as an adsorbent for removing organic substances such as methylene chloride and toluene and malodor.
The adsorbent hydrophobized in the present invention is optimally used in an exhaust gas treatment apparatus for removing or recovering organic solvents discharged from industrial processes such as chemical factories, pharmaceutical factories, film factories, and solvent coating booths. . In particular, since the gas discharged from the industrial process is not only an organic solvent but also an exhaust gas having a certain level of humidity, the exhaust gas containing humidity is cited as one of the factors that degrade the original performance of the adsorbent.

  The solvent recovery apparatus using the hydrophobized adsorbent of the present invention has two or more hydrophobized adsorbents installed, and alternately switches adsorption and desorption with water vapor for each tower, or desorbs with adsorption and vacuum degassing. The solvent discharged can be recovered by switching alternately for each column. In particular, in desorption using water vapor, OH groups are formed on the surface of the adsorbent due to the influence of residual moisture, and gradually show hydrophilicity. Therefore, the adsorbent originally possessed by the adsorbent could not be fully exhibited. However, if the hydrophobized adsorbent of the present invention is optimally used, excellent performance can be exhibited even when repeated adsorption and desorption are repeated.

Hereinafter, the present invention will be specifically described with reference to examples. The examples are illustrative of the invention and are not limiting.

Production Example 1
n-octadecyltriethoxysilane (3.00 g, 8 mmol), ethanol (156 g), water (5 g), organosilica sol (manufactured by Nissan Chemical Industries, 30% methanol solution) 12.5 g (silica sol, equivalent to 3.75 g), and bath temperature 90 The mixture was heated at reflux overnight at ° C.
An appropriate amount of the obtained dispersion was collected and dried at 60 ° C. for 2 hours, and the solid obtained was subjected to IR measurement. As a result, absorption of C—H of the octadecyl group could be confirmed.

Production Example 2
n-octyltriethoxysilane 2.22 g (8 mmol), ethanol 156 g, water 5 g, organosilica sol (manufactured by Nissan Chemical Industries, 30% methanol solution) 12.5 g (silica sol 3.75 g equivalent) were mixed, and bath temperature 90 The mixture was heated at reflux overnight at ° C.
An appropriate amount of the obtained dispersion was sampled and dried at 60 ° C. for 2 hours to perform IR measurement of the solid. As a result, absorption of C—H of the octyl group could be confirmed.

Production Example 3
Methyltriethoxysilane 1.42 g (8 mmol), ethanol 156 g, water 5 g, organosilica sol (manufactured by Nissan Chemical Industries, 30% methanol solution) 12.5 g (silica sol 3.75 g equivalent) were mixed, and the bath temperature was 90 ° C. Heated to reflux overnight.
When an appropriate amount of the obtained dispersion was collected and dried at 60 ° C. for 2 hours to perform IR measurement of the solid, it was possible to confirm absorption of C—H of the methyl group.

Production Example 4
1.92 g (8 mmol) of phenyltriethoxysilane, 156 g of ethanol, 5 g of water, organosilica sol (manufactured by Nissan Chemical Industries, 30% methanol solution) 12.5 g (equivalent to 3.75 g of silica sol) were mixed, and the bath temperature was 90 ° C. Heated to reflux overnight.
An appropriate amount of the obtained dispersion was collected and dried at 60 ° C. for 2 hours, and the solid obtained was subjected to IR measurement. As a result, absorption of phenyl C—H could be confirmed.

Production Example 5
Using a tubular furnace with an inner diameter of 30 mm and a length of 40 cm, about 10 g of activated carbon fiber having a fiber diameter of 16 μm was heated to 900 ° C. at a temperature rising rate of 5 ° C./min while flowing 1 L / min of nitrogen, and then for 1 hour. After being held, the activated carbon fiber subjected to heat treatment was obtained after the temperature in the furnace gradually decreased to room temperature.

Examples 1-9, Comparative Examples 1-2
About 6 g of activated carbon fibers, the hydrophobic silica sol dispersion prepared in Production Examples 1 to 4 was collected so that the solid content would be 1 to 3 mass fraction% of the activated carbon fibers, and this was collected with ethanol. Dilution was performed to obtain a hydrophobization treatment solution of about 50 g. The prepared hydrophobizing solution was included in activated carbon, and this was air-dried at 150 ° C. for 6 hours. The presence or absence of the hydrophobic metal oxide particles attached to the activated carbon fibers was confirmed by IR measurement.
The obtained hydrophobized activated carbon fiber was subjected to a methylene chloride adsorption performance test in the presence of water. In addition, the test was similarly performed on the activated carbon fiber that was not hydrophobized and the activated carbon fiber that was heat-treated in Production Example 5. The results are shown in Table 1.

[Methylene chloride adsorption performance test in the presence of water]
About 4 g of each sample is packed in two adsorption towers, water vapor at a temperature of 100 ° C. and about 1 g / min is introduced, desorbed for a certain period of time, a certain number of times, and the temperature in the adsorption tower stabilizes. A methylene chloride gas having a concentration of 350 ppm (Co), a temperature of 25 ° C., a humidity of 80%, and a linear velocity of 0.1 m / s flows into the tower, and after adsorbing for a certain period of time, water vapor is introduced into the tower and desorbed for a certain period of time. The cycle was repeated 10 times, the outlet concentration (C) was measured with the passage of time during adsorption, and the breakthrough rate C / Co = 0.05 hour (min) was measured.
1. Breakthrough time In the above methylene chloride adsorption performance test, the time (min) that the methylene chloride started to breakthrough at a breakthrough rate C / Co = 0.05
2. Performance ratio Ratio of breakthrough time between hydrophobized adsorbent and untreated adsorbent

Example 10 and Comparative Example 3
About 150 g of activated carbon, the hydrophobic silica sol dispersion prepared in Production Example 1 was collected so that the solid content would be 3 mass% of the activated carbon, diluted with ethanol, and about 50 g of hydrophobized. A treatment liquid was used. The prepared hydrophobizing solution was included in activated carbon, and this was air-dried at 150 ° C. for 6 hours. The presence or absence of hydrophobic metal oxide particles attached to the activated carbon was confirmed by IR measurement.
The resulting hydrophobized activated carbon was subjected to a toluene adsorption performance test in the presence of water. In addition, the same test was performed on activated carbon that was not hydrophobized. The results are shown in Table 2.

[Toluene adsorption performance test in the presence of water]
About 130 g of each sample is packed in two adsorption towers, water vapor at a temperature of 100 ° C. and about 1 g / min is introduced, desorbed for a certain period of time, a certain number of times, and after the temperature in the adsorption tower is stabilized, A cycle in which toluene gas with a concentration of 300 ppm (Co), temperature of 25 ° C., humidity of 80%, and linear velocity of 0.3 m / s is flowed into the tower, adsorbed for a certain period of time, and then steam is introduced into the tower and desorbed for a certain period of time. Was repeated 10 times, and the outlet concentration (C) was measured with the passage of time during adsorption, and the time (min) when the breakthrough rate C / Co = 0.05 was measured.

[Fiber diameter]
The fiber diameter of the activated carbon fiber was measured according to JIS K 1477.
[Granularity]
The particle size of the activated carbon was measured according to JIS K 1474.
[Amount of hydrophobic metal oxide particles attached]
Measure the mass of the adsorbent before adhering the hydrophobic metal oxide, adsorb the hydrophobic metal oxide to the adsorbent, and apply the hydrophobic metal oxide particles from the mass after air drying at 150 ° C. for 6 hours. Was calculated.
[BET specific surface area]
The BET specific surface areas of the hydrophobized adsorbents obtained in Examples and Comparative Examples were vacuum degassed at 150 ° C. using an automatic specific surface area / pore distribution measuring device (manufactured by Shimadzu Micromeritic, TRISTAR 3000 type). The sample was measured by the nitrogen gas adsorption method and calculated by the BET method.

As is clear from Tables 1 and 2, in Examples, organic substances such as methylene chloride are efficiently adsorbed without being affected by moisture, as compared with Comparative Examples.

  The hydrophobized adsorbent of the present invention has practicality that the adsorption capacity can be maintained without blocking the pores of the porous body, while the surface of the porous body is hydrophobized, and is excellent in repeated desorption performance, Since it exhibits excellent adsorption ability under high humidity conditions, it can be suitably used in a solvent recovery apparatus for organic substances such as methylene chloride.

Claims (11)

A hydrophobic adsorbent characterized in that hydrophobic metal oxide particles surface-modified with a silicon compound represented by formula (1) are attached to a porous body.
R—Si (CH ₃ ) _n (—X) _3-n (1)
Where R is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 3 carbon atoms or an aryl group having 6 to 8 carbon atoms, and X is an alkoxy group having 1 to 3 carbon atoms. , C represents a carbon atom, H represents a hydrogen atom, Si represents a silicon atom, and n represents 0 to 2. The hydrophobized adsorbent according to claim 1, wherein the metal oxide particles have a size of 5 to 200 nm. The hydrophobized adsorbent according to claim 1 or 2, wherein the metal oxide particles are silica, titania, alumina or zirconia. The hydrophobized adsorbent according to any one of claims 1 to 3, wherein the metal oxide particles are sol. The hydrophobized adsorbent according to claim 4, wherein the metal oxide particles are an organosilica sol. The hydrophobic adsorbent according to any one of claims 1 to 5, wherein the porous body is activated carbon, zeolite, alumina, or silica. The hydrophobized adsorbent according to claim 6, wherein the porous body has a fibrous shape, a pellet shape, a granular shape, a honeycomb shape, or a paper shape. The hydrophobized adsorbent according to any one of claims 1 to 7, wherein 1 to 4 mass% of hydrophobic metal oxide particles are attached to the porous body. The hydrophobized adsorbent according to any one of claims 1 to 7, wherein hydrophobic metal oxide particles are impregnated in an amount of 1 to 3% by mass to the porous body. The method for producing a hydrophobized adsorbent according to any one of claims 1 to 9, wherein the hydrophobic metal oxide particles are dissolved (dispersed) by adding a water-soluble organic solvent, and the porous body is immersed and dried. . The solvent collection | recovery apparatus using the hydrophobization adsorbent in any one of Claims 1-9.