JPS59186641A - Adsorbent for filter for cleaning atmospheric air - Google Patents

Abstract

PURPOSE:To improve adsorptive performance of active carbon for harmful gases in the atmospheric air by depositing additionally polyalkyleneimine to the active carbon. CONSTITUTION:0.1-50wt% polyalkyleneimine such as polyethyleneimine having 300-100,000 average mol.wt. is deposited to active carbon having >=0.15cc/g pore volume for 30-300Angstrom pore size. For the deposition of polyalkyleneimine, a soln. of polyalkyleneimine is applied by spraying and then drying, or by other process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an activated carbon adsorbent having excellent adsorption performance for harmful gases in the atmosphere.

In general, activated carbon adsorbents adsorb malodorous substances in the atmosphere with a relatively high equilibrium adsorption amount even at low concentrations, and are therefore advantageous compared to other adsorbents and are currently widely used. But formaldehyde, acetaldehyde? It has the disadvantage that the equilibrium adsorption amount is low for gas components that are highly irritating at low concentrations such as acrolein cyanide, hydrogen sulfide, and mercaptan, and that the adsorbed gas is concentrated and then desorbed.

In order to solve the above drawbacks, a method for removing aldehydes by impregnating ordinary granular activated carbon with an ammonium salt such as ammonium chloride (Japanese Unexamined Patent Publication No. 53-29292), or a method using low molecular weight compounds such as ethylenediamine, triethylenetetramine, and anison, etc. A method has been proposed in which aldehydes are removed by impregnating amines (Japanese Patent Application Laid-Open No. 56-53744). However, since conventional activated carbon for impregnation is coconut shell-based or coal-based activated carbon, the pore diameter is 30 to 300X (7).
Since the pore volume is small, the impregnating effect of the adhesive is small. Furthermore, since conventional impregnants have low molecular weight, they tend to clog the microscopic pores of activated carbon, which is the impregnating carrier, so that the effect of improving adsorption performance is small and there is a problem of re-scattering during use.

The present invention has been made as a result of careful examination to eliminate such drawbacks.
This is what was discovered. That is, 1 pore diameter 30~30o
An adsorbent for air purification filters has been discovered in which a polyalkylene imine is impregnated with an activated carbon material having a pore volume of X of o, 1 acc/9 or more.

The activated carbon material used in the present invention has a pore diameter of 30λ to 30
Cyanide and aldehydes are activated carbon materials with a pore volume of 0λ of 0.15eC/9 or more.

0, that is, pore diameter 30X, which is necessary for efficiently removing irritating and harmful gases such as hydrogen sulfide and mercaptans.
3002 with a pore volume of less than 0.15eC/G1, the impregnation effect is not sufficient even if the polyalkyleneimine used in the present invention, for example, ethyleneimine polymer, is impregnated. This is not preferable because the effect cannot be fully exhibited.Also, in pores with a pore diameter of less than 30A, only a flat surface will be formed even if the alkyleneimine polymer is impregnated, and if the pore diameter exceeds 30OA, This is not preferred because the surface area is significantly reduced.

The pore diameter and pore volume of activated carbon are calculated using Cranston-Inklay (O
ra: e+5ton-enginekley). The relationship between the multimolecular adsorption layer and the relative pressure is t (
A): 4.3 (5/In (Pa/P)) V”
Frenkel-Hal
sey ) (Keii Tominaga "Adsorption" Kyoritsu Shuppan).

The above-mentioned activated carbon material having a large pore volume at a specific pore diameter is produced, for example, by the following method. That is, (1) it is produced by supporting an oxidation catalyst such as ferric chloride or magnesium acetate on cellulose-based fibrous activated carbon, and then subjecting it to reactivation treatment in a high-temperature steam gas atmosphere. Furthermore (1
1) After carbonizing fine wood valve powder, etc., 900 to 1300
It is manufactured through highly activated treatment in a combustion gas atmosphere containing high-temperature water vapor at ℃. Or (bone char obtained by steaming the bones of cattle or water buffalo)
ar) and animal activated carbon such as blood charcoal obtained by thermally decomposing blood with potassium carbonate (for example, Tsuruo Araki's "Activated Carbon" (Maru@)), as well as 0ψ sawdust, water pulp, regenerated cellulose fiber, Mix cotton, etc. with an acidic aqueous solution such as zinc chloride, phosphoric acid, or chloride, and add 600 to 9
Calcination in an inert atmosphere at 00°C 7, Activation method or (V) Petroleum raw coke, carbon black, oil carbon, asphalt 1 activated carbon, etc. with agents such as potassium hydroxide, sulfurizing power 1, potassium carbonate, potassium sulfate, etc. 7
Examples include those produced by a method of heat treatment at 00 to 1200°C. Of course, the pore diameter is 30-3
The method is not limited to the above method as long as it provides activated carbon with a 00A pore volume of 0.15 cc/G' or more.

On the other hand, the polyalkyleneimine used in the present invention is, for example, polyethyleneimine having an average molecular weight of 300 to 100,000 and having repeating units of fOH, OH, NH'jn obtained by ring-opening polymerization of ethyleneimine with a suitable catalyst. used. In addition, the amount of polyalkyleneimine attached to the activated carbon material is 0.1 to 50% by weight, preferably 1 to 30% by weight.
Weight%. The impregnation method can be obtained by spraying a polyalkylene imine solution and then drying it, or by immersing a predetermined amount of activated carbon material in a polyalkylene imine aqueous solution of a predetermined concentration to adsorb polyalkylene imine molecules, and filtering. . In addition, in order to facilitate the filter molding method using the wet method, after impregnating polyethyleneimine, 10
By heating above 0℃, activated carbon material can be heated to 1000%
Chemical bonds may be formed with surface functional groups such as H groups. Alternatively, polyalkylene imine may be attached by polymerizing alkylene imine on the activated carbon material.

The shape of the activated carbon material used in the present invention is preferably a granulated material (granular material) having a fibrous average particle diameter of 200 mesh (74 .mu.m) or less and a large amount of macropores in the size of a fine powder from the viewpoint of the adhesion effect.

Below are the margins for forming a filter using the adsorbent of the present invention:
(1) After impregnating polyethylene on fine powdered activated carbon, disperse it in a solution such as N sodium alginate, carboxymethyl cellulose, water glass, silica sol, 1 polystyrene solution,
(II) Chemically bonded polyalkylene imine-impregnated activated carbon material is applied to wood pulp, fibers, etc. A method of wet-mixing the activated carbon material with polyvinyl alcohol, etc. to obtain a breathable sheet and making it into a filter, or (110) A method of forming the above sheet into a corrugated cardboard sheet and forming it into a honeycomb shape to obtain a filter. A method of applying polyalkyleneimine impregnation treatment after forming into a sheet or sheeting or step processing, or () using the finely powdered activated carbon material with a binder such as water glass, polyvinyl alcohol, clay, methyl cellulose, etc. to form a material with a pore diameter of approximately There are methods such as molding into porous granules with a large macro-pore volume of 1000λ or more, applying an impregnation treatment, and using them as a packed bed filter.In particular, the adsorbent has a good balance between contact efficiency with gas and air permeability. A honeycomb-like filter or a 7-ohm material/filter with good compatibility is preferred.6 The adsorbent of the present invention has polyalkylene ylang molecules of medium molecular weight or higher attached to activated carbon with a specific pore distribution. , cyanide, aldehydes, hydrogen sulfide, mercaptans, and other harmful and highly irritating gases; no re-scattering of impregnated chemicals; Therefore, the present invention can be used in a car, a train car, a coffee shop, a movie theater, a pachinko parlor, or a home living room where cyanide/formaldehyde, acetaldehyde, hydrogen sulfide, etc. are likely to be filled. Installing a filter using an adsorbent has the advantage of efficiently removing the above-mentioned harmful gases, having low ventilation resistance, and less reducing indoor heating and cooling effects.

Examples of the present invention will be described below, but the present invention is not limited to these Examples.

Example L Comparative example L BIT method surface area 30cl//P and pore diameter 3
Pore volume of 0 to 300 A [o, oacC/9 (7) regenerated ce/l/a-thread fibrous activated carbon, magnesila acetate A1
After impregnating and supporting 0% heavy electric charge, an adverse activation treatment was performed in a combustion gas atmosphere containing 900 tl of water vapor, and the pore diameter was 30 ml.
~300A pore volume was o, 4o cc/9 (D fibrous activated carbon was obtained.

With a composition of 60 parts of the above activated carbon, 40 parts of NBKP pulp (softwood bleached craft pulp) beaten to a pH of S R30', and 7 parts of polyvinyl alcohol fiber,
Activated carbon heaving machine 459 with Yankee type wet paper machine
The paper was made with a weight of / '. Paper thickness 0.20M
Activated carbon paper was obtained. The carbon paper was then formed into a single-sided corrugated cardboard sheet with a pitch width of 3.1 m and a pitch height of E and l- using a corrugating machine. The single-sided corrugated cardboard sheet was made of polyethyleneimine (Nippon Shokubai Chemical Industry ■5p-200+
After being immersed in a 6 wt % methanol solution with a molecular weight of 10,000 for one day and night, it was filtered and dried to obtain a single corrugated cardboard sheet impregnated with 30 wt % polyethyleneimine.

After cutting the corrugated sheet into honeycomb filters with a layer length of 50 m5, the air aeration rate was +50e+w/36c containing lOppm of acetaldehyde and 10ppn of cyanide.
The results shown in Table 1 were obtained.

As a comparative example, an attempt was made to evaluate the performance of a honeycomb filter made of the corrugated cardboard sheet to which ethylenediamine was attached (Comparative Example 1).

Comparative Example 2 Precursor activated carbon fiber of Example 1 (pore diameter 30-300
Example 1 using the pore volume of A: 0.08 squares/9)
In the same way as above, we made a honeycomb filter using paperboard and polyethyleneimine impregnation, and attempted to evaluate the performance of N-acetaldehyde and cyanide. Table 1 shows the results.

Example 2 Fine wood valve powder was carbonized under an inert atmosphere of 500'O, and then activated for several seconds under a combustion gas shearing atmosphere of 1300°C to reduce the volume of pores with a pore diameter of 30 to 300A. Activated carbon of 0.29 CC/9 was obtained. The activated carbon was pulverized in a ball mill to obtain powdered activated carbon with an average particle size of 20 μm. The activated carbon was added to 5% by weight of polyethyleneimine (Nippon Shokubai Kagaku Kogyo h, Sp-018) common solution.
By soaking day and night, polyethyleneimine is
It was adsorbed in weight percent, filtered and dried. After dispersing 15 parts of the activated carbon in a sodium alginate water bath and making a uniform paste, 1. A 30-thick urethane foam sheet (Bridgestone Tire ■: Everite Scott Filter, HR-30) was immersed, dehydrated, and dried to obtain an activated carbon-impregnated sheet. Example 1
Similarly, the ability to remove acetaldehyde and Yaan-containing gas was evaluated. The results are shown in Table 1.

Comparative Example & Commercial coconut shell activated carbon (pore diameter 30-300χ, pore volume o, 1occ/9, BIT ratio normal surface area 100 d
/ri) was coarsely pulverized, and then finely pulverized using a ball mill into particles having an average particle size of 2 μm.

The activated carbon was impregnated with polyethyleneimine in the same manner as in Example 2 to obtain a urethane foam filter, and its gas removal ability was evaluated. The results are also listed in Table 1.

The following are blank spaces: Example 3, Comparative Example 4 Sawdust from coniferous wood was carbonized at 500°C for one day and night in an open hearth.

The carbide was heated in a fluidized activation furnace for a residence time of 10 to 15 seconds and a temperature of 1.
Activation treatment was performed at 200 to 1300°C in an atmosphere containing 10% water vapor, with a specific surface area of 110011'/9 and a pore diameter of 30.
Activated carbon with a pore volume of ~300 A and a pore volume of 0.21 cc/liter was obtained.

The activated carbon was pulverized in a ball mill to an average particle size of 20 μm.

The activated carbon was granulated using water glass and then immersed in a hydrochloric acid bath to insolubilize the water glass binder.

A granular adsorbent with a particle size of 35 to 50 mesh was obtained.

The granular activated carbon material was immersed in a water bath solution of polyethyleneimine (Nippon Shokubai Kagaku Kogyo ■, p-1000, average molecular weight: o, ooo) for a day and night, and then dried to obtain an adsorbent with 10% by weight of impregnated iron. Ta.

As a comparative example, commercially available coal-based activated carbon (pore diameter 30 to 300λ, pore volume o, oacc/r, BKT ratio slope surface area 800w19
) was pulverized with a ball mill to an average particle size of 20 plI, granulated with water glass as in Example 3, and then insolubilized into a glass column with a diameter of 1.6 em, containing 25 p of sulfurized tree leaves. When air was flowed at a flow rate of Locm/1gθ0, the initial removal rate of the former was 100%, while the removal rate of the latter was 50%.

Example 4, Comparative Example 6 After drying, beef bones were pulverized into 16 to 30 meshes and heated in a quartz tube furnace under a nitrogen gas stream to 800'l:l in about 5 hours, with a yield of 5o%. EFT method specific surface area processing 00
Bone charcoal with a bi/y carbon content of 10 wt% was obtained.

The pore diameter was 30 to 300χ and the pore volume was 0.18 cc/p.

After granulation treatment was carried out using the same method, it was immersed in a hydrochloric acid bath solution to insolubilize the water glass binder.

A granular adsorbent having a particle size of 35 to 5o mesh was obtained.

The adsorbent contains polyethyleneimine (Nippon Shokubai Chemical Industry @A
5p-006: Molecule it 600) Water-soluble Mni&
[Then, a 20% by weight impregnation treatment was performed by drying. As a comparative example, commercially available palm carbon activated carbon (pore diameter 3
0-300+X pore volume o, obcc/g, EFT method specific surface area voo*/9) was finely pulverized in a ball mill, granulated with water glass, and then N insolubilized to Fifj L, particle size 3
An impregnation treatment of 20% by weight of δ-n (5p-006) was performed.

When the adsorbent was packed in a glass column with a diameter of 1.6 mm so that the height was 3 scratches, and air containing 1 Oppz of formaldehyde was flowed at a flow rate of 10 cm/Bec, the initial removal rate was within the former's initial removal rate. Whereas it was 95%.
The removal rate of the latter was 10%.

Claims (1)

[Claims] (1) Pore volume of pore diameter 30 to 300A is 0.158
An adsorbent for an air purification filter, characterized in that a polyalkylene imine is attached to an activated carbon material of f1!79 or more. (2) The adsorbent for an air purification filter according to claim (1), wherein the activated carbon material is powdered activated carbon. (8) The adsorbent for air purification filters according to claim 1, wherein the activated carbon material is fibrous activated carbon. (4) Claim 1, wherein the polyalkylene imine is polyethyleneimine. Adsorbent for air purification filters.