DE2329645A1 - Filtering granules for eliminating unpleasant odours - containing acidic or basic chemisorption material and moisture absorbent - Google Patents

Abstract

Loose filtering material for eliminating unpleasant odours e.g. from industrial plants and domestic kitchens, consists of a granular mixt. of (I) an acidic or basic chemisorption material e.g. phthalic acid, sodium bisulphate, sodium hydroxide, or a foamed phenolic resin, and (II) a moisture absorbent e.g. a cellulose ether and/or bentonite.

Description

Collo Rheincollodium Köln GmbH Hersei plant, 5303 Bornheim-Hersel, Simon-Arzt-Str. 2

Filters for removing foreign gases contained in the air, such as, in particular, gases containing sulfur and / or nitrogen

The invention relates to a filter for removing foreign gases contained in the air, such as in particular sulfur and / or nitrogen-containing gases, consisting of a hydrophilic, open-cell foam material as a carrier for Filter active components.

Filters are used to remove mostly foul-smelling sulfur or nitrogen-containing foreign gases from the air.

409882/0477

2: ·) '_'. I 6 4 5

knows, in which the carrier for a catalytically active redox system is a fine-pored, hydrophilic and open-cell plastic foam is used in which Cell structure the catalysts of the redox system are built in. As a redox system, oxides in particular become more polyvalent Metals such as manganese, iron, copper, cobalt, nickel and silver oxide are used in certain combinations. These substances are optionally combined with substances with an adsorbing effect, such as above all activated carbon, the raw foam mixture added in very fine-grained form, so that they • after foaming in the cell structure of the foam are firmly and inextricably linked.

Filters of this type, which are used in the form of sheets or plates, can be used to eliminate odors Especially to remove unpleasant odors and gaseous pollutants from the air, e.g. from protein decomposition products or carbohydrate breakdown products, use even at room temperatures.

It is also known to use filters of the aforementioned type as bulk material filters to train. In this case, the filter material consists of foam particles in the form of foam flakes or a foam granulate, which with adsorbent Substances and catalytically active substances is added.

The foreign gases to be removed from the air are

409882/0477

ORIGINAL INSPECTED

/.-ι -. ~ ί ο 4 b

In practice, these are mostly mixtures of chemically different gases, the concentration of which fluctuates considerably may be subject to. In order to achieve optimal results, there is therefore the requirement to use the filter-active substances as far as possible on the respective area of application and purposes of the filter. On the other hand, the filter-effective substances must be in sufficient proportions be present, that the foreign gases contained in the air were during the passage of the air through the filter as possible largely removed. It goes without saying that large filter throughput capacities and the longest possible filter service life are required are to be aimed for. The filter should also be used even at relatively low temperatures, possibly even at room temperature.

The invention is based on the object of creating a filter which meets the aforementioned requirements as far as possible largely fulfilled. In particular, the invention aims a highly effective filter material, which is relatively can be easily adapted to the respective purpose and which with a relatively long filter service life A high level of effectiveness is also developed when the air to be filtered is chemically different Contains foreign gases.

The filter according to the invention is characterized in that at least one active ingredient component from one or the Foreign gases chemically binding chemosorptive substance exists on the cell wall framework of the porous foam

U 0 3 S 8 II UA 7 7 - 4 -

ORiGiNAL INSPECTED

mrterials is liable.

The use of foam οίε carrier material for the chemosorptiv-active substances offers the possibility of extraordinary large quantities of chemosorbents, which are about up to Make up 500 vol. 70 of the foam volume and preferably about 200 to 5OO vol.% Of the foam volume, am To store foam, which is in terms of a good FiI-ter efficacy and a long filter life is important. The weight of the hemosorbents absorbed by the foam is expediently about 1.5 to 2.5 times the foam weight. Because the chemosorptive Substances essentially overlay the entire cell wall surface of the foam, the result is an extraordinary one large contact area, what in terms of chemical conversion of the foreign gases entrained by the air and accordingly of importance with regard to a high filter efficiency is.

According to a preferred embodiment of the invention, a small-piece, flocked or granular foam material used, its Particle size is preferably at least for the most part below 10 mm. In this case, some of the small-sized foam material can contain chemosorptive substances Be impregnated, which react with acidic foreign gases, while another part of the small-sized foam material chemosorp-

409882/0477

contains tivc otoffe. The foam particles Ip impregnated with the various chemocorptive substances can be used in intimate mixing as a filter for debris, the mixture in one of the filters to be filtered. Air flowed through Filterkomiaer or the like. is introduced.

Since the vast majority of chemosorbents are in Inside the open display material pores, it can consist of a mixture of flakes or grajoulat Bulk material filters to no denominator mutual neutralization of the alkaline and acidic Cheinosorbents come. The possibility of self-neutralization, which would make the filter according to the invention at least partially ineffective is therefore not given.

It goes without saying that the Hengen parts of the different small-sized foam material containing chemical substances according to the concentrations of Foreign gases contained in the air are set, which is achieved by proportional mixing of the aforementioned Way impregnated foam can easily be reached. For those consisting of one or more components Debris filters can be added to the flake or granule

409882/0477

- 6 - 2?.? " 6 A 5

shaped foam material other filter-effective substances, such as in particular adsorbent substances, preferably activated carbon, to mix mechanically in the desired proportions in order to increase the filter efficiency. Also exists the possibility of mechanically adding catalytically active substances from a redox system or adding more to the flake mixture Add foam flakes to which catalytically active Substances of the redox system are bound. In this case, a multi-component filter is obtained which, in addition to the chemosorptive substances also contains adsorbing and / or catalytically active substances.

Instead of a bulk material filter with thorough mixing of the various components, which can also be used as eddy current filters, the various components can also be arranged one behind the other in separate filter layers in the air stream. Those with the various chemosorptive agents Foam particles impregnated with substances can be placed one above the other as a separate layer as a multi-layer filter bulk material body in a filter space, with optionally between the layers another layer of adsorbing substances (preferably activated carbon) and / or catalytic substances of a redox system, preferably bound to a hydrophilic, small-sized and open-pored foam material will.

It goes without saying that the chemical reaction between the chemosorptive substances bound to the foam

409882/0477 -7-

ORlGlNAL INSPECTED

and the foreign gases must take place in the moist medium, generally a low level, due to the moisture content of the air and the residual moisture of the filter material the resulting trace moisture is sufficient. However, in order to ensure sufficient humidity in every case or To ensure the moisture content of the filter even after long periods of inactivity, it is advisable to use the foam material in addition to the chemosorptive substance (s), at least one moisture-retaining substance, such as in particular a swelling agent or the like. to add. Various substances such as bentonite, collagen, Carbohydrates, alginates, silica gel, water glass and the like can be used. The substances mentioned can mechanically dem Foam flake material are mixed in. However, the substances are preferably added to the chemosorptive substance and with this applied to the cell structure of the foam so that they are finely distributed in the chemosorptive substances are embedded and firmly adhere to the foam material. The proportion of these substances (Swelling agent), based on the proportion of chemosorptive substances, is expediently about 5 to 30% by weight, preferably 10 to 20% by weight. But it does exist also the possibility of using the substances mentioned, such as bentonite in particular, additionally or exclusively in the foam material to incorporate so that they are firmly integrated into its cell structure. In terms of compliance with a sufficient moisture of the filter according to the invention

- 8 - U 0 9 8 B 2 I Ü U 7 7

ORIGINAL INSPECTED

materirlc is also the hydrophilicity of the Sclic.iwotof: 7ε of Lr, interpretation.

Uni the called twffect of the cliernosorptiv-v.irkei'deri fabrics rr rt.r. To improve cell walls of the foam framework, et recommends itself, the chemosorptive-active substances an adhesive or binding agent to be added in small proportions. Preferably be for this purpose water-soluble or hydrophilic binders, such as in particular Methyl cellulose, carboxymethyl cellulose, water glass and the like, are used. These substances do not improve the adhesion of the chemosorptive substances to the foam, but are also able to store moisture and from the air, which, as mentioned, is required for the chemical conversion. The proportion of the binder Based on the proportion of chemosorptive substances, it is preferably about 1 to 10% by weight, expediently 1 to 5

Chemosorbing substances are to be understood below as those chemical substances that are carried along with the air Gases react chemically, with the reaction products attaching to the display material. To the distance Saurer Gf-.se, such as H..S, SOp, NO, NOp, are here alkaline substances, expediently salts of strong bases and weak acids, such as soda, potash and / or sodium

triumbicarbonet, used while alkali- for removal ^; shear gases, such as ammonia and amines, acidic substances, e.g. organic mono- or polycarboxylic acids, organic

£ 09882/0477

niche bicarboxylic acids, organic sulfonic acids, Λΐΐιίοοί.αιίί'υ.; - acids, preferably acidic salts, e.g. I; e ~ trium bisulfate, Ilono-iiatriumphosphet and the like., Can be used. It goes without saying that the type of verier, deter. chfudosorptiven substances on the type of to be removed: Freindgar.e must be voted on.

As mentioned, the effectiveness of the invention Filters especially when filtering air in mixtures voTj foreign gases are contained, so that the filter material also has adsorbing substances and / or catalytically active substances, such as in particular those of a redox system, are added. In this case it takes place the destruction of the foreign gases once through gheraosorption, on the other hand through catalytic decomposition, i.e. through oxidation under the action of catalytic! Fabrics one Redox system, v / elches in the well-known manner:> from oxides or Hydroxides of polyvalent metals, like manganese us \ ·:., Consists.

There is still the courtesy to use the inventive er Filter material oil-adsorbing or oleophilic substances, v; ie e.g. Meloiain resin in fine-grain form or in the form of foam To add flakes, for example in proportions of up to 10 wt. / These substances can also be added to the small-sized foam material mix mechanically.

Instead of a debris filter ε, a multi-layered filter can also be used Filters are provided, consisting of individual ones arranged one behind the other in the airway, with the different cherao-

409882/0477

- 10 -

Sorptive substances impregnated foam mats or the like. consists. Between the impregnated foam mats, intermediate layers made of adsorbent and / or catalytic active substances, which are also bound to a hydrophilic, open-cell foam material, for example will.

A hydrophilic, open-cell polyurethane foam is expediently used as the carrier for the chemosorptive substances used, although other foams with these properties, such as polyvinyl alcohol or viscose foam, are also used can be used. The mean pore size of the foam material is expediently between 0.3 and 5 mm, preferably between about 0.5 and 2 mm.

In the following some examples for the production of a hydrophilic, open-cell foam material are given, which can be used as a carrier for the chemosorptive substances:

Example I:

To produce a hydrophilic, soft and open-cell foam, 125 parts by weight of a polymer Product of ethylene diamine with propylene oxide and ethylene oxide and 125 parts by weight of a polypropylene oxide-ethylene oxide mixed product Neutralized with 25 parts by weight of 10% sulfuric acid, then with 3 parts by weight Water and 2 parts by weight of tin dioctoate added and up to

409882 / Ü4 7 7 -11-

ORIGINAL INSPECTED

uniform mixture stirred and adjusted to 20 ⁰ C. 60 parts by weight of tolylene diisocyanate are then added to this mixture in an intensive mixer, whereupon the mixture is stirred until it is creamy and then poured into a coolable vessel. This quickly forms a light, soft, elastic foam that has hardened at around 50 ° C and a dwell time of one hour in the drying cabinet.

Example Ia:

In the production of the polyurethane foam according to Example I, tolylene diisocyanate is added to the mixture of substances before the addition 50 parts by weight of montmorillonite powder (bentonite) and 15 parts by weight of dehydroaluminum silicate of a molecular sieve added. During the subsequent foaming and curing, these adsorbing substances are incorporated into the foam structure involved. They increase the adsorbing properties of the foam, in particular with respect to protein decomposition products and, due to their swellability, are able to store moisture, so that the moisture content of the foam is increased.

Example II:

Instead of the polyurethane foam mentioned in the preceding examples, the following foam can also be used Composition can be used:

- 12 - ^ 09382/04/7

ORIGINAL INSPECTED

- 12 - 10 2329645 Polyoxypropylene glycol Parts by weight Condensation products from ethylene oxide 10 and propylene oxide on ethylenediamine 0.02 Il sulfuric acid 0.04 π Hydrogen peroxide 0.10 It glycerin 0.60 It Methylene chloride 1.20 It Potash 1.20 It Molecular sieve 1.20 M. zinc oxide Il

Tolylene diisocyanate

24.36 parts by weight 15.0 parts by weight

This polyurethane foam can also contain adsorbing substances, e.g. bentonite (finely ground under 50 / U) in proportions of 3 to 5% by weight and / or catalytic Substances of a redox system, namely e.g. the following substances added will:

3.60 parts by weight

Manganese Oxide Hydrate Copper I Oxide

Iron III oxide hydrate

2.40 "
0.70 -

Example Ha;

The foam raw mixture mentioned in Example II Polyurethane foam can also contain 5 to 20, preferably 8 to 15 parts by weight of activated carbon with a grain size below 3 mm, preferably less than 1 mm, which are incorporated into the cell structure of the foam during the foaming process.

409882/047

- 13 -

is bound.

Examples for the further processing of a foam material and its impregnation with chemosorptive substances:

Example 1:

A hydrophilic, open-cell foam with an average pore size of preferably 0.8 to 2 mm, for example a Polyurethane foam according to the above Examples I and II is comminuted by means of a flocculation machine and then sieved on a 10 mm sieve. The sieve passage thus has a particle size below 10 mm, the The predominant proportion of the foam flakes is in the range from 2 to 5 mm.

The foam flake material produced in this way is then soaked in a saturated soda solution, whereupon the water is expelled by heating, with a residual moisture of about 10 % expediently remaining. This treatment can be carried out in a mixer with a rotating mixer into which the flake material and the soda solution are introduced. After the flake material has been soaked with the soda solution, hot air at a temperature of about 150 to 200 ° C is introduced into the mixer to drive off the excess water and dry the flake material to such an extent that soda is in a firm adhesive layer on the cell wall surfaces of the foam.

- 14 -409882/0477

The small-sized material produced in this way consists of about 30 wt. 56 of foam and about 60 wt. 96 of soda, while the remainder is formed by the residual moisture and possibly further additives of the aforementioned type incorporated into the foam material.

A small-piece foam material of the aforementioned type impregnated with soda can advantageously be used to remove, for example, SOp, H ₂ S or nitrogen gas (NO ₂ ) from the air. Hydrogen sulphide is found in particular in the exhaust air from cover shops, sewage treatment plants, chicken farms, iron foundries, pulp industries and the like, while NO or NO _{2 are} mainly found in the exhaust air from chemical industries or in car exhaust fumes.

The layer thickness of the material made from the aforementioned foam formed debris filter is expediently 30mm, while the speed with which the with the foreign gases loaded air flows through the bulk material filter, is preferably set to about 0.3 to 0.5 m per second.

Example 1a:

Example 1 is modified as follows: 1% by weight of methyl cellulose is added to the soda solution as an adhesive added before the foam material is soaked or impregnated with this solution. This increases the adhesive strength of the soda on the cell wall structure of the foam improved. In addition, the methyl cellulose improves the

- 15 -9882/0477

Water retention capacity of the foam material.

Instead of methyl cellulose, carboxymethyl cellulose can also be used Added in proportions of 0.5 to 2% by weight of the soda solution will.

Example 1b;

The details of Examples 1a or 1b apply, but with activated carbon mechanically replacing the small-sized foam material is admixed, preferably in such an amount that the proportion of the bulk material contained in the mixture Activated carbon and the proportion of impregnated foam material each make up about 50% by weight.

There is also the option of adding activated carbon to the raw foam mixture to be viewed in proportions of about 5 to 15 wt. before the foam is foamed. The finished foam then contains the activated carbon firmly bound into his cell wall system; he is then in the manner described with the chemosorbing substance impregnated.

Example 1c:

A small piece of foam material impregnated with soda according to Example 1 is also coated with activated carbon and one small, flaky or granular foam material mechanically mixed, which incorporated catalytic substances of a redox system and possibly bentonite (but does not contain any chemosorptive substances). This

A09882 / Ü477 - 16 -

329 64

used as a debris filter in intimate mixing Mixture then contains:

impregnated foam material 50% by weight activated carbon 25 "

small pieces mixed with incorporated catalytic substances Foam material 25 "

Example 1d;

The foam material mentioned in Example 1 is impregnated with a solution of a material chemosorptiven (soda), which in addition 1 wt.% Carboxymethyl cellulose solution and 100 g per liter of bentonite contains.

Example 2:

A hydrophilic, small-sized and open-pored foam material, for example one according to Examples I and II, is impregnated with a saturated sulfamic acid solution, whereupon the excess water is driven off to a residual moisture of about 10 % . The treatment can be carried out according to Example 1. The foam material obtained in this way is impregnated with sulfamic acid, which adheres to the cell wall structure. Here, too, the proportion by weight of the foam material (without impregnation) is around 30% by weight and the proportion by weight of the amidosulfonic acid attached to the foam is around 60% by weight (plus residual moisture and any other additives of the type mentioned that are incorporated into the foam or contained in the impregnation agent). .

- 17 4098S2 / Ü477

A filter medium of the aforementioned type is particularly suitable for removing NH ₇ - or amines from the air. These substances can be found, for example, in the exhaust air from pigsties, fish processing plants and chicken farms, etc.

Those listed in the previous examples la to id Variants can also be implemented in example 2.

Example 3:

25% by weight of impregnated foam material according to Example 1 and 50% impregnated foam material according to Example 2 are intimately mixed with 25% by weight of activated carbon and used as a bulk filter. Such a filter is particularly suitable for filtering the exhaust air from fish processing plants and chicken coops or chicken farms.

Example 4:

As homogeneous a mixture as possible is made from the following substances :

10% by weight of impregnated foam material Example 2

10 "impregnated foam material according to example 1

60 "small piece foam material

(less than 10 mm) without impregnation with chemosorbent substances, but with incorporated catalytic agents of a bedox system

20 "activated carbon

409882/0477 -18-

Such a bulk material mixture is particularly suitable for removing kitchen odors, smells in restaurants, Meeting rooms and the like.

Example 5s

A mixture of the following substances is produced:

10 wt. # Impregnated foam material according to Example 1

5 "impregnated foam material according to example 2

60 "small-sized hydrophilic and open-pored foam material (not impregnated with chemosorbents) with incorporated catalysts of a redox system (e.g. manganese and iron oxide)

25 "activated carbon

Such a bulk material mixture can be particularly advantageous for piltering the air in living rooms, assembly rooms, schools, Hotels, cinemas, etc., possibly in air conditioning units.

- 19 -

409882/0477

Example 6;

A small, hydrophilic and open-pored foam material of the type mentioned is impregnated in the manner described with one of the following chemical substances:

Peroxo compound

Sodium persulfate

Barium peroxide

Sodium perborate

Sodium percarbonate

Such a filter material can be used for the oxidation of foreign gases entrained in the air, in particular for the destruction Use sulfur-containing protein decomposition products, e.g. sulfur dioxide and mercaptan.

Example 7;

A hydrophilic, open-pored, small-piece foam material (less than 10 mm) is used as the starting material, which is soaked and impregnated with a concentrated salt solution of the following composition:

Sodium persulfate 5% by weight

Soda 95 "

After the excess water has been driven off, the percentage by weight of impregnating substances in the finished filter material is about 60%, while the percentage by weight of foam (including incorporated substances) is about 30 % .

A mixture of the foregoing material becomes the following

- 20 -

4 0 9 8 3 2 I U 4 7 7

2 3 2 9 6 A 5

Composition made:

5 wt.? 6 impregnated foam material of the aforementioned Art

25 "with an acidic chemosorptive substance according to Example 2

25 "activated carbon

25 "small, hydrophilic and open-cell (not impregnated) foam material with incorporated substances of a redox system (e.g. Iron and manganese oxide)

Such a multi-component filter material is particularly suitable as a bulk material filter for filtering the exhaust air of cover shops (removal of hydrogen sulfide, amines and protein decomposition products).

Example 8;

A foam material of the type mentioned is with a Impregnated solution of soda and water glass, whereupon the excess water is driven off.

Example 9t

Instead of the polyurethane foams mentioned in Examples I and II, foams are made from polyvinyl alcohol or viscous foams are used.

It goes without saying that the proportions of the individual components of the filter material according to the invention depend on the respective application or the proportion of foreign gases in the filtering air must be adjusted by what simple

- 21 - 409882/0477

ORIGINAL INSPECTED

Mixture of the various chemosorptive agents Substances impregnated filter components can be achieved in the required proportion. The added ones Adsorbing substances (activated carbon) remove those foreign gases by adsorptive means that are released from the chemosorptive Substances may not be destroyed. They also increase the effects of chemosorption as they do Keep the substances to be destroyed in the area of action of the chemosorptive substances for a long time. Using of water glass, this also has the function of a binder and a chemosorptive impregnating agent. The use of swellable, water-soluble binders, such as methyl cellulose in particular or carboxymethyl cellulose, increases the adhesion of the chemosorptive substances to the foam material and immediately improves the moisture absorption of the filter material. It may be advisable to use the bulk material Swelling bodies (carbohydrates, alginates, collagen, silica gel, etc.) in proportions by weight of preferably up to 8% by weight add to get a moisture depot. Such substances, especially carbohydrates, also have a Moisture-regulating effect with changing air humidity. When used in air conditioners and the like. cause They maintain a largely constant air humidity, as they release water into the air when the air humidity is reduced and water from the air when the humidity rises

- 22 -

409882/0477

take up. While a predominantly acidic filter material is used for filtering the air in pig farms, a combination material consisting of an acidic material with a high proportion of alkaline components can be used to filter the exhaust air from chicken farms and the like. For filtering the exhaust air from foundries, rolling mills, etc., an alkaline filter material combined with an oxidizing material is expediently used. A multi-component material consisting of a combination of alkaline chemosorbents with a low proportion of acidic chemosorbents and adsorptive substances is used to remove fragrance from the skin in apartments, restaurants and the like. For filtering the exhaust air from slaughterhouses, a filter material is expediently used, consisting of a mixture of alkaline chemosorbents with a small proportion of acidic chemosorbents and adsorptive substances.

It goes without saying that the impregnation of the foam material should be carried out expediently so that the foam pores are not completely closed, but for the air to be filtered remain open. The impregnation material forms a thin surface coating of the foam material.

- 25 409882/0477

Claims (20)

- 23 claims 1.Filter to remove foreign gases contained in the air, such as, in particular, gases containing sulfur and / or nitrogen, consisting of a hydrophilic, open-cell foam material as a carrier for filter active components, characterized in that at least one active ingredient component consists of a chemosorptive substance which chemically binds the foreign gas or gases and which is on the cell wall framework of the porous foam material adheres. 2. Filter according to claim 1, characterized in that the weight fraction of the cheaosorptive substances is greater than that of the foam material used as the carrier material and preferably about 1.5 to 2.5 times the same amounts to. 3. Filter according to claim 1 or 2, characterized in that the foam material in addition to the chemosorptive substance (s) or at least one swelling agent, such as e.g. Contains bentonite, collagen, carbohydrate, alginate, silica gel, water glass and the like. 4. Filter according to claim 3, characterized in that the swelling agent is mixed with the chemosorptive substance adheres to the surface of the foam material. 40988'2 / 047 7 - 24 - ? 3? q R Λ 5 5. Filter according to one of claims 1 to 4, characterized in that that a swelling agent is incorporated into the foam material. 6. Filter according to one of claims 3 to 5, characterized in that that the proportion of swelling agent, based on the amount of chemosorptive substances, about 5 to 30% by weight, preferably 10 to 20% by weight. 7. Filter according to one of claims 1 to 6, characterized in that that the chemosorptive substance by means of a water-soluble hydrophilic binder, such as in particular Methyl cellulose, carboxymethyl cellulose, water glass or the like. Adheres to the foam surface. 8. Filter according to claim 7, characterized in that the proportion of the binder, based on the total amount of the chemosorptive substance, 1 to 10 wt. %, Preferably 1 to 3 wt.% Is. 9. Filter according to one of claims 1 to 8, characterized in that the chemosorptive substances for removing acidic gases, such as in particular HpS, SO ₂ , NO, NOp, from salts of strong bases, preferably from soda, potash, sodium bicarbonate, etc., consist . 10. Filter according to one of claims 1 to 8, characterized in that that the chemosorbents for removal 409882/0477 -25- ORIGJiSiAL INSPECTED alkaline gases, e.g. amines, ammonia, from acidic substances, e.g. organic mono- or polycarboxylic acids, organic bicarboxylic acids, organic sulfonic acids, sulfamic acids, preferably acidic Salts of strong acids, such as sodium bisulfate, ΓΊοηο sodium phosphate, exist. 11. Filter according to one of claims 1 to 10, characterized in that that it also contains adsorbing substances and / or catalytically active substances of a redox system. 12. Filter according to one of claims 1 to 11, characterized in that that the foam material consists of a small, flaky or granular material . $ 1. Filter according to claim 12, characterized in that the size of the foam particles is at least predominantly Part is less than 10 mm. 14. Filter according to claim 12 or 15 »characterized in that that part of the small-sized foam material is alkaline Substances as chemosorptive substances and another part of the small-sized foam material are acidic substances contains as chemosorptive substances, whereby the foam material loaded with the different chemical substances - 26 - 409882/0477 particles are intimately mixed in the filter chamber or arranged in layers one behind the other in the airway. 15. Filter according to claim 14, characterized in that the multi-component filter material consisting of several chemosorptive substances, fine-grained adsorbent substances, such as activated carbon in particular, are mixed in. 16. Filter according to claim 14 or 15, characterized in that that the multicomponent filter material foam particles are also mixed, which act catalytically Have substances and / or adsorbent substances. 17 · Filter according to one of claims 1 to 11, characterized in that that several foams impregnated with different chemosorptive substances mats and the like in the air are arranged one behind the other. 18. Filter according to one of claims 1 to 17, characterized in that that the foam material with oxidative-acting substances, such as in particular organic peroxo compounds, Sodium persulfate, barium peroxide, sodium perborate, sodium percarbonate etc. is impregnated. 19. Filter according to one of claims 12 to 18, characterized in that that the impregnated with the chemical substances - 27 409882/0477 Foam material oleophilic substances, such as in particular Melamine resin or melamine resin foams, up to about 5% by weight, are added. 20. Filter according to one of claims 1 to 19 »characterized in that that the impregnated foam material consists of polyurethane foam. 409882/0477