JP2006272047A - Aldehyde gas adsorbent and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aldehyde gas adsorbent suitable for use in everyday life and enhancing a long term absorption ability relative to an aldehyde gas, and its production method. <P>SOLUTION: In the aldehyde gas adsorbent, polyethyleneimine in 5-40 vol.% to the total fine pore vomume is carried on calcium silicate hydrate having a specific surface area of 50-300 m<SP>2</SP>/g and a total fine pore volume of fine pores having a fine pore diameter 5-100 nm of 0.4-2 ml/g. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aldehyde gas adsorbent and a method for producing the same.

  In recent years, there has been a rapid increase in consumer needs for deodorization, particularly for tobacco odor. The main component of this tobacco odor is acetaldehyde and the like. In addition, as seen in sick house / sick building syndrome, health problems due to formaldehyde are also attracting attention. An amine-based aldehyde remover is provided as a removal and deodorant for these aldehyde gases.

  For example, Patent Document 1 discloses an exhaust gas treatment method in which exhaust gas is brought into contact with water in which a nitrogen-containing compound having reactivity with aldehydes is dissolved or dispersed, and the aldehydes are washed and removed.

  However, in this method, the use of a liquid amine compound is essential. Then, since the liquid amine compound emits a strong unpleasant odor, there arises a problem that it is not suitable for application to daily life such as living spaces such as living rooms and kitchens.

  Further, in Patent Document 2, an adsorbent obtained by impregnating activated carbon with one or more of ammonium salt, sulfite, and acidic sulfite and a gas containing an aldehyde are contacted. A method for adsorptive removal of aldehydes is disclosed. Patent Document 3 discloses an adsorbent for aliphatic aldehydes composed of activated carbon to which aniline is added in an amount of 3 to 30% by weight (vs. activated carbon).

  However, these methods have a problem in that the amount of aldehyde gas that can be adsorbed is small because the total amount of pores of the activated carbon used is small.

  Furthermore, Patent Document 4 discloses a deodorant comprising a compound having a primary amino group in the molecule and a magnesium silicate clay mineral. In this method, the magnesium silicate clay mineral is scaly and can adsorb compounds between the layers.

  However, in this method, it is impossible to adsorb aldehyde gas in a large amount, and there arises a problem that the long-term absorption ability is inferior.

Therefore, it is desired to provide an adsorbent that is suitable for daily use and has an excellent long-term absorption capacity for aldehyde gas.
JP-A-51-44587 JP-A-53-29292 JP-A-56-53744 JP-A-9-28778

  The main object of the present invention is to provide an aldehyde gas adsorbent which is suitable for use in daily life and has improved long-term absorption capacity for aldehyde gas, and a method for producing the same.

  As a result of intensive studies in view of the problems of the prior art, the present invention has found the above object by using an aldehyde gas adsorbent having a specific configuration, and has completed the present invention.

  That is, this invention relates to the following aldehyde gas adsorbent and its manufacturing method.

1. Polyethyleneimine is added to calcium silicate hydrate having a specific surface area of 50 to 300 m ² / g and a pore size of 5 to 100 nm and a cumulative pore volume of 0.4 to 2 ml / g. An aldehyde gas adsorbent characterized by being supported by 5 to 40% by volume of the pore amount.

  2. A cement composition comprising the adsorbent according to item 1 and a cement.

3. A calcium silicate hydrate having a specific surface area of 50 to 300 m ² / g and a pore size of 5 to 100 nm and an accumulated pore volume of 0.4 to 2 ml / g is impregnated with a polyethyleneimine solution. And then drying the aldehyde gas adsorbent.

  According to the aldehyde gas adsorbent of the present invention, aldehyde gas can be adsorbed in a large amount over a long period of time by carrying a certain amount of polyethyleneimine on a specific calcium silicate hydrate. That is, excellent long-term absorption ability can be exhibited.

  The aldehyde adsorbent of the present invention can adsorb not only aldehyde gas but also ketone gas and the like. Examples of such aldehydes and ketones include acetone, methyl ethyl ketone, dibutyl ketone, normal valeraldehyde, isovaleraldehyde, acetaldehyde, formaldehyde and the like. Also, depending on the target gas, it can be mixed with other deodorants and used together.

  Furthermore, since the aldehyde gas adsorbent of the present invention can maintain a highly dispersible powder form, it has good dispersibility and is easy to handle during granulation and molding. Therefore, it is suitable for daily life. Of course, it can also be used for applications other than daily life, for example, experimental instruments such as aldehyde adsorption containers and aldehyde adsorption columns packed in columns.

Aldehyde gas adsorbent The aldehyde gas adsorbent of the present invention has a specific surface area of 50 to 300 m ² / g and a cumulative pore volume of pores having a pore diameter of 5 to 100 nm is 0.4 to ² ml / g. It is characterized in that polyethyleneimine is supported on calcium acid hydrate in an amount of 5 to 40% by volume of the cumulative pore amount.

The specific surface area of the calcium silicate hydrate for use in the present invention is about 50 to 300 m ² / g, preferably from 70~200m ² / g, more preferably about 100~180m ² / g approximately. If the specific surface area is too small, the contact area between the supported polyethyleneimine and the aldehyde gas may decrease, and the amount of adsorbed aldehyde gas may decrease. On the other hand, when the specific surface area is excessively large, the pore diameter of the calcium silicate hydrate becomes small. Therefore, the aldehyde gas is difficult to diffuse into the pores, and the long-term absorption capacity may be reduced. In addition, calcium silicate hydrate having an excessively large specific surface area is economically disadvantageous because it requires a large amount of energy for its production.

  The specific surface area used in the present invention is measured by the BET method calculated from the nitrogen adsorption amount.

  The cumulative pore amount of pores having a pore diameter of 5 to 100 nm of the calcium silicate hydrate of the present invention is about 0.4 to 2 ml / g, preferably about 0.5 to 1.8 ml / g, more preferably 0.8. About 1.5 ml / g. When the total amount of pores is small, the amount of polyethyleneimine that can be supported is small, and thus the amount of gas absorption may be small. On the other hand, calcium silicate with an excessively large cumulative pore amount requires a great deal of energy for its production and is economically disadvantageous.

  The cumulative amount of pores having a pore diameter of 5 to 100 nm used in the present invention is calculated from the pore volume and specific surface area determined by the BET method according to the Drymore-Heal method.

  The calcium silicate hydrate used in the present invention may be any of known natural calcium silicate and synthetic calcium silicate hydrates.

  Examples of these natural calcium silicate hydrates or synthetic calcium silicate hydrates include, for example, zonotlite, tobermorite, fosjaite, gyrolite, hireblandite, rosenhanite, trussite, rielite, calciochondrite. Affilite, quasicrystalline calcium silicate hydrate (CSHn) and the like. Among these, quasicrystalline calcium silicate hydrate (CSHn) is preferable.

  Synthetic calcium silicate hydrate is usually obtained by mixing a lime raw material and a silicic acid raw material, or by subjecting calcium silicate to a hydration reaction, hydrothermal synthesis, or the like. Examples of the lime raw material include slaked lime, and examples of the silicic acid raw material include silica gel, silica stone powder, and fly ash. Examples of the source of calcium silicate include various Portland cements, mixed cements, and granulated blast furnace slag.

  The calcium silicate hydrate of the present invention may be primary particles (single crystals) or aggregates (secondary particles) in which the primary particles are entangled three-dimensionally.

  The polyethyleneimine used in the present invention is not particularly limited as long as it is a compound having a linear or branched structure containing a primary to tertiary amine. Usually, it is a water-soluble polymer obtained by polymerizing ethyleneimine. The molecular weight is not particularly limited, but is usually about 100 to 100000, preferably about 300 to 70000, more preferably about 1000 to 30000.

By supporting this polyethyleneimine on a specific calcium silicate hydrate, the Schiff reaction mechanism represented by the following formula (1) is effectively exhibited, and it is considered that aldehyde gas can be adsorbed better. Moreover, it is thought that it can adsorb | suck more well also with the ketone gas etc. which cause the same Schiff reaction.

  The amount of polyethyleneimine supported is about 5 to 40% by volume, more preferably about 8 to 30% by volume, most preferably about the total amount of pores having a pore diameter of 5 to 100 nm of calcium silicate hydrate. About 10 to 25% by volume.

  If polyethyleneimine is excessively supported, polyethyleneimine will block pores in calcium silicate hydrate. As a result, the area in contact with the aldehyde gas becomes small, and efficient gas adsorption becomes difficult. In addition, due to the viscosity of polyethyleneimine, the particles (aldehyde adsorbent powder) aggregate to form a clay, which is complicated to handle. In addition, when the amount of polyethyleneimine supported is small, the aldehyde gas adsorption amount decreases.

  The shape of the aldehyde gas adsorbent of the present invention is not particularly limited and can be appropriately determined according to the desired purpose. For example, it may be in the form of powder or granular.

Cement composition The cement composition of the present invention contains the aldehyde gas adsorbent and cement.

  The cement is not particularly limited and can be appropriately determined according to product characteristics. For example, normal Portland cement, early-strength Portland cement, medium heat Portland cement, low heat Portland cement, alumina cement, and mixed cement such as blast furnace cement and fly ash cement are also included.

  The mixing ratio of the aldehyde gas adsorbent is not limited, and is usually about 10 to 3000 parts by weight, preferably about 70 to 2000 parts by weight with respect to 100 parts by weight of cement.

  When water is blended, the blending ratio is not limited and is usually about 40 to 200 parts by weight with respect to 100 parts by weight of cement.

  In addition to the above components, the cement composition of the present invention may contain additives such as a high-performance water reducing agent, an AE agent, a setting modifier, and a shrinkage reducing agent.

Method for Producing Aldehyde Gas Adsorbent The method for producing an aldehyde gas adsorbent of the present invention has a specific surface area of 50 to 300 m ² / g and an accumulated pore amount of pores having a pore diameter of 5 to 100 nm is 0.4 to 0.4. It is characterized by including a step of impregnating a calcium silicate hydrate of 2 ml / g with a polyethyleneimine solution and then drying.

  The impregnation method is not limited as long as the calcium silicate hydrate can be impregnated with the polyethyleneimine solution. For example, the method of immersing calcium silicate hydrate in a polyethyleneimine solution, the method of apply | coating and spraying a polyethyleneimine solution to calcium silicate hydrate are mentioned.

  In these methods, it is preferable to carry out under reduced pressure from the viewpoint of supporting polyethyleneimine in the pores of calcium silicate hydrate in a short time.

  The solvent used in the polyethyleneimine solution is not particularly limited as long as the polyethyleneimine is dissolved, and examples thereof include water and alcohol.

  The concentration of the polyethyleneimine solution is not particularly limited, and may be appropriately determined depending on the impregnation method, the solvent, and the like. For example, when water is used as a solvent, it is usually about 1 to 8 w / w% aqueous solution, preferably about 2 to 5 w / w% aqueous solution. Moreover, when using the immersion method etc., you may carry out under stirring.

As another impregnation method, a slurry containing a calcium silicate compound having a specific surface area of 50 to 300 m ² / g and an accumulated pore amount of pores having a pore diameter of 5 to 100 nm of 0.4 to ² ml / g. And a method of adding polyethyleneimine powder to.

  In this method, the amount of polyamine compound that can be supported by calcium silicate hydrate is usually added. When an excessive amount of polyamine is added, the calcium silicate hydrate after the supporting treatment may be washed with pure water to remove the excess polyamine compound adhering to the surface. In this method, similarly to the above impregnation method, it may be carried out under stirring or under reduced pressure.

  The production method of the present invention includes a step of drying after the impregnation. The drying method is not limited and may be by heating or reduced pressure. For example, drying can be performed by a general-purpose machine such as a shelf dryer, a paddle dryer, a disk dryer, or a vacuum dryer.

  The drying temperature may be appropriately determined according to the drying method and the like, but is usually about 70 to 200 ° C, preferably about 75 to 150 ° C. Further, the drying time may be appropriately determined depending on the drying method, the drying temperature, and the like.

  After drying, if necessary, it may be crushed using a known machine such as a cage mill, a pin mill, a ball mill, or a vibration mill.

  When the obtained aldehyde gas adsorbent is in powder form, after adding a binder or the like, a gas adsorbent granule can be produced by using a known granulator such as extrusion granulation or a pan pelletizer. it can.

  Examples of the binder include hydraulic compositions such as cement, carboxymethyl cellulose (CMC), starch, and sugars. Moreover, you may add water other than a binder as needed.

  The cement composition of the present invention can be cured and cured after the aldehyde gas adsorbent, cement and water are mixed and formed into a predetermined shape. This curing improves the strength of the cement molded body obtained by molding.

  A known method can be used as the curing method, and examples include normal temperature curing, steam curing, and autoclave curing. In particular, when performing steam curing and autoclave curing, an aldehyde gas adsorbent formed by supporting high molecular weight polyethyleneimine having a high boiling point can be suitably used.

  The shape to be molded is not particularly limited and can be appropriately determined according to the product characteristics. Examples thereof include a honeycomb shape, a pleat shape, and a lattice shape.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples.
Example 1
After adjusting the pH to 7 by adding hydrochloric acid to No. 3 water glass (manufactured by Tosoh Sangyo Co., Ltd.), the resulting gel silica gel is filtered off, washed with water, then dried at 100 ° C. for 24 hours and dried. Silica gel was obtained.

  A suspension obtained by adding 100 g of the above-mentioned dry silica gel and 63 g of slaked lime to 100 g of water was pulverized and reacted in a ball mill for 3 hours while being heated to 80 ° C. to obtain a calcium silicate hydrate slurry. The obtained slurry was dried at 80 ° C. under reduced pressure to obtain calcium silicate hydrate powder.

  10 g of the above calcium silicate hydrate powder was added to 3 g / w% aqueous solution of polyethyleneimine prepared by adding 3 g of polyethyleneimine (Epomin P200 (average molecular weight = 10,000)) manufactured by Nippon Shokubai Co., Ltd. to 100 g of pure water. added. Next, after immersing under reduced pressure at 40 ° C. for 2 hours, the desired aldehyde gas adsorbent powder was obtained by drying at 80 ° C. for 2 hours. Table 1 shows the physical properties of the powder obtained in Example 1.

(Example 2)
In a kneading part of a disk pelleter (manufactured by Fuji Powder Co., Ltd.), 100 parts by weight of the aldehyde gas adsorbent powder obtained in Example 1 and carboxymethyl cellulose as a binder (Marrose ME-300000: manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) 1 part by weight and 88 parts by weight of water were added and kneaded sufficiently uniformly. Subsequently, by drying at 80 ° C. for 2 hours, an aldehyde gas adsorbent granule having a diameter of 5 mm × 10 mm was obtained.

(Example 3)
The following raw materials were uniformly mixed to prepare a cement composition.
Aldehyde gas adsorbent powder obtained in Example 1: 30 parts by weight ordinary holland cement (manufactured by Sumitomo Osaka Cement): 30 parts by weight quartzite powder (manufactured by Sumitomo Osaka Cement): 20 parts by weight Crown Talc 3S (Matsumura Sangyo Co., Ltd.) (Made by company): 20 parts by weight Marporose ME-300000 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.): 3 parts by weight Water: 19 parts by weight Next, the above cement composition was put into a Henschel mixer (model “FM75E” (Mitsui Miike Seisakusho)). Kneaded. The obtained kneaded product was extruded using a extruder (trade name “V-50”, manufactured by Universe Co., Ltd.) (die: 230 cells / inch ² ).

 The obtained honeycomb formed body was steam-cured at 30 ° C. for 24 hours and then dried at 80 ° C. for 2 hours.

(Comparative Example 1)
Aldehyde gas adsorbent powder was prepared in the same manner as in Example 1 except that the concentration of the prepared polyethyleneimine aqueous solution was 10 w / w%. Table 1 shows the physical properties of the powder obtained in Comparative Example 1.

(Comparative Example 2)
Adsorption of aldehyde gas in the same manner as in Example 1 except that the calcium silicate hydrate used was calcium silicate hydrate ("Sun Parfer" manufactured by Asahi Kasei Kogyo Co., Ltd.) having a specific surface area of 30 m ² / g. An agent powder was prepared. Table 1 shows the physical properties of the powder obtained in Comparative Example 2.

(Comparative Example 3)
5 g of polyamine (P200 (average molecular weight = 10,000) manufactured by Nippon Shokubai Co., Ltd.) was added to 100 g of pure water to prepare a polyamine 5 w / w% aqueous solution. Of granular activated carbon (crushed material of 4GS-S φ4mm × 5mm made by Tsurumi Coal), the above polyamine 5w / w% aqueous solution was immersed in 10g of activated carbon that passed through a 500μm sieve for 2 hours under reduced pressure at 40 ° C and then dehydrated. . Next, the resultant was dried at 80 ° C. for 2 hours to obtain polyamine-supported powdered activated carbon. Table 1 shows the physical properties of the powdered activated carbon obtained in Comparative Example 3.

(Comparative Example 4)
Granular product of granular activated carbon (Tsurumi Coal 4GS-S φ4mm × 5mm) was used.

(Comparative Example 5)
The following raw materials were uniformly mixed to prepare a cement composition.
Polyamine-supported powdered activated carbon obtained in Comparative Example 3: 30 parts by weight ordinary holland cement (manufactured by Sumitomo Osaka Cement): 30 parts by weight quartzite powder (manufactured by Sumitomo Osaka Cement): 20 parts by weight Crown Talc 3S (Matsumura Sangyo Co., Ltd.) Manufactured): 20 parts by weight Marporose ME-300000 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.): 3 parts by weight Water: 19 parts by weight Next, the above cement composition was subjected to Henschel mixer (model “FM75E” (manufactured by Mitsui Miike Seisakusho)). Kneaded. The obtained kneaded product was extruded using a extruder (trade name “V-50” (manufactured by Universe Corporation)) (die: 230 cells / inch ² ) to form a 45 mm prismatic honeycomb molded body.

 The obtained honeycomb formed body was steam-cured at 30 ° C. for 24 hours and then dried at 80 ° C. for 2 hours.

(Test Example 1)
0.5 g of the adsorbent was collected in a 10 L gas bug (trade name “Flex Sampler”), sealed, and sealed with 10 L of CH ₃ CHO gas (concentration: 200 ppm) (2.5 minutes at 4 L / min). The time when the encapsulation was completed was 0 minute. The gas concentration in the gas bug was measured using a gas detector tube for CH ₃ CHO (manufactured by Gastec) at each elapsed time. The measurement time was 60 minutes. The relationship between CH ₃ CHO gas concentration and measurement time is shown in FIG.

(Test Example 2)
After the completion of Test Example 1, the residual gas in the gas bug was discharged. Subsequently, 10 L of CH ₃ CHO gas (200 ppm) was similarly sealed again, and the concentration of residual gas after 60 minutes was measured. This cycle was repeated several times. The relationship between the residual gas concentration and the number of tests is shown in FIG.

(Test Example 3)
A glass column (φ18 mm × 300 mm) was filled with the granulated product of Example 2 and Comparative Example 4, respectively. The test apparatus at this time is shown in FIG. CH ₃ CHO gas (200 ppm) was allowed to flow through this column at a rate of 100 ml / min, and the change over time in the gas concentration at the column outlet was measured. The change with time of the gas concentration is shown in FIG.

(Test Example 4)
The honeycomb molded bodies (45 mm square × thickness 50 mm) produced in Example 3 and Comparative Example 5 were processed into φ50 mm × thickness 50 mm, and then sealed in series in a glass column (φ50 mm × 130 mm). The test apparatus at this time is shown in FIG. CH ₃ CHO gas (200 ppm) was allowed to flow through this column at a rate of 100 ml / min, and the change over time in the gas concentration at the column outlet was measured. This change in gas concentration with time is shown in FIG.

FIG. 1 shows the relationship between the CH ₃ CHO gas concentration in the gas bag and the measurement time in Example 1 and Comparative Examples 1 to 3. FIG. 2 shows the relationship between the CH ₃ CHO residual gas concentration in the gas bag and the number of tests in Example 1 and Comparative Examples 1 to 3. FIG. 3 shows a measurement diagram of changes with time in gas concentration when the granulated products of Example 2 and Comparative Example 4 are used. FIG. 4 shows a measurement diagram of changes with time in gas concentration when the honeycomb formed bodies of Example 3 and Comparative Example 5 are used. FIG. 5 shows changes with time in gas concentration in Example 2 and Comparative Example 4. FIG. 6 shows changes with time in gas concentration in Example 3 and Comparative Example 5.

Claims (3)

Polyethyleneimine is added to calcium silicate hydrate having a specific surface area of 50 to 300 m ² / g and a pore size of 5 to 100 nm and a cumulative pore volume of 0.4 to 2 ml / g. An aldehyde gas adsorbent characterized by being supported by 5 to 40% by volume of the pore amount. A cement composition comprising the adsorbent according to claim 1 and cement. A calcium silicate hydrate having a specific surface area of 50 to 300 m ² / g and a pore size of 5 to 100 nm and an accumulated pore volume of 0.4 to 2 ml / g is impregnated with a polyethyleneimine solution. And then drying the aldehyde gas adsorbent.

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