DE102015012410B4 - Process for the production of a respiratory protection filter made of rigid activated carbon material and a respiratory protection filter made of rigid activated carbon material - Google Patents

Abstract

A method for producing a respiratory protection filter from a rigid activated carbon material, wherein the respiratory protection filter comprises, as a monolithic molded body, a multiplicity of channels which are not connected to one another and which are arranged in parallel, and the channels are covered with at least one metal compound, and wherein the method has the following steps: I. Preparation of the impregnation solution whereby the impregnation solution is prepared by dissolving ammonium chloride, zinc carbonate and sodium molybdate in a 25% ammonia solution with stirring and with slight warming; II. Providing the monolith, comprising the following steps a) to e): a) mixing carbon particles and at least one binder to produce an extrudable mass, wherein the carbon particles are particles of carbon material and wherein the carbon material is activated carbon or coke, b) extruding the obtained Mass to obtain a strand with channels, c) hardening of the strand obtained, d) carbonization of the strand or strand sections to obtain carbon molded bodies or activated carbon molded bodies, e) activation of the carbonized carbon molded bodies; III. Impregnating the monolith by dipping or passing the impregnation solution; IV. Drying of the monolith.

Description

The invention relates to a method for producing a respiratory protection filter from a rigid activated carbon material, as well as a respiratory protection filter which is produced according to such a method, the respiratory protection filter being equipped as a molded body with a plurality of non-interconnected channels arranged in parallel. The channels are covered with metal connections. The invention further relates to the use of the respiratory protection filters and respiratory protection masks equipped with the respiratory protection filters.

Respiratory protection filters are classified as particle filters or gas filters, depending on whether the respiratory protection filters absorb or adsorb solids or gases. There are also combination filters that offer protection against gases and particles. With respiratory protection filters in escape filter devices, a distinction is also made between fire escape and industrial escape filter devices. While the filters of the fire escape devices primarily protect against carbon monoxide (CO), the filters of the industrial escape devices are designed to protect against various industrial gases. This is also reflected in the relevant standards. For example, EN 403 (breathing apparatus for self-rescue - filter devices with hood for self-rescue in the event of fire) describes the gas absorption capacity required for CO, while DIN 58647-7 (breathing apparatus for self-rescue - escape filter devices) describes the absorption capacity for the gases known as ABEK gases Substances is described. The abbreviation ABEK stands for gases and vapors of organic compounds with a boiling point> 65 ° C (A), inorganic gases and vapors, with the exception of carbon monoxide (B), sulfur dioxide and other acidic gases and vapors (E) and ammonia and organic ammonia derivatives (K). A wider spread than the German norm DIN 58647-7 has the European EN14387 standard (Respiratory protective devices - gas filters and combination filters - requirements, testing and labeling), which also describes filters against ABEK gases, in this case for work equipment.

The structure of the known respiratory protection filters can be divided into those in which the filter material is in the form of (a) granules or powders as packed fixed beds, (b) loaded nonwovens, and (c) monolithic filter bodies.

Of these known adsorbent structures, only the packed fixed beds have achieved commercial importance or have been developed to such an extent that they meet the strict filtration requirements for gas and steam breathing protection. Practically all such fixed-bed filters for respiratory protection are of cylindrical construction, have a certain bed thickness and inputs and outputs arranged in parallel planes.

So far, respiratory protection filters filled with granulated activated carbon (activated carbon bulk) have achieved economic importance. In addition, a few filters with so-called fixed activated carbon are known, which either contain activated carbon granulate supported on foam or are filled with activated carbon pads in which activated carbon granulate is glued by means of polymers. The activated carbon can be used both untreated and impregnated in multi-range filters.

All previously known systems have a relatively high breathing resistance and can only be mechanically stressed to a limited extent and must therefore be filled and fixed in a housing made of metal or plastic. The housing is provided with an adapter for connection to a mask or hood. The respiratory protection filters are exchangeable, but not recyclable and thus generate waste with the known disadvantages.

A disadvantage of using activated charcoal beds is that if the activated charcoal packing is exposed to vibrations, the activated charcoal particles rub against one another and produce abrasion. The homogeneity of the bed can also suffer from this.

Monolithic filter bodies containing activated carbon are known from the prior art. Open-pore foams, phenoplasts, polyurethanes, plaster of paris, paper supports and carbon frameworks have been proposed as a matrix for the activated carbon.

In the U.S. 5,078,132 A activated charcoal moldings are proposed for use in gas masks. They are self-supporting porous gas filter materials, which consist of a cast body of particles of the adsorber material and the thermoplastic binder.

But there are already activated carbon molded bodies with a monolithic structure and a large number of parallel channels ( DE 101 04 882 A1 ) has been proposed. Unlike the porous bodies, these cannot be flown through freely, rather the flow occurs separately in the channels. The use of shaped activated carbon bodies with parallel channels has so far not found widespread use.

An example of the use of non-monolithic filters with parallel channels for respiratory protection is the WO 2011/041144 A2 . the WO 2011/041144 A2 but does not disclose that the parallel channels are covered (= impregnated) with metal compounds.

the US 2004/0 259 729 A1 describes a method for purifying breathable air in which a carbon-based monolith structure is impregnated with copper, silver, zinc, molybdenum and triethylenediamines. The impregnation takes place in a multi-stage process.

the U.S. 5,914,294 A describes a monolith for filtering volatile organic components from a fluid stream which is extruded from a mixture of activated carbon, a ceramic molding material, a flux and water and then dried and fired.

the US 2009/0 093 561 A1 describes a monolithic, carbon-based foam that can be used in the field of respiratory protection and is made from an emulsion containing vinyl chloride monomers, a crosslinking agent and a surfactant. A foam is produced from the emulsion, which is then sulfonated and then carbonized.

the US 2010/0 275 922 A1 relates to a Soprtionsmittel which comprises an impregnated activated carbon, wherein the impregnation contains zinc and molybdenum components. The Soprtionsmittel is filled as a bulk material in a container.

The post-published WO 2016/075 451 A1 describes personal respiratory protection equipment with an activated carbon filter as a filter element.

the DE 36 86 858 T2 relates to bonded adsorbent structures which are suitable, for example, for the filtration of gases and vapors. The adsorbent structures are essentially of uniform thickness and density throughout, so that the air flowing through it flows as uniformly as possible.

the DE 101 04 882 A1 proposes an activated charcoal shaped body in honeycomb form, which is extruded from a mixture of activated charcoal, water, novolak powder, clay, cellulose ether, liquid starch, wax, polyacrylamide and soap. This shaped activated carbon body is also intended for use as an adsorption filter.

the WO 2011/041144 A2 describes an air filter with a first and a second filter, the first filter being a monolithic filter and containing active particles.

The object of the present invention is to provide a filter for use as a respiratory protection filter which is easy to handle, provides a low breathing resistance and has a good and constant filter performance even with fluctuating gas volume flows.

Another object of the present invention is to reduce the impregnation effort compared to the impregnation of particulate activated carbon. In addition, it would be desirable to be able to dispense with the stabilizing housing required when using packed solid beds made of granules or powders.

This problem is solved by the subject matter of the independent claims. Preferred embodiments are the subject matter of the subclaims or are described below.

1. I. Ansetzen der Imprägnierlösung wobei das Bereitstellen der Imprägnierlösung erfolgt, indem Ammoniumchlorid, Zinkcarbonat und Natriummolybdat unter Rühren und bei leichter Erwärmung in einer 25% Ammoniaklösung gelöst werden, [siehe Ausführungsbeispiele];
2. II. Bereitstellen des Monolithen, umfassend die folgenden Schritte a) bis e):
   1. a) Vermengen von Kohlenstoffpartikeln und zumindest einem Bindemittel unter Herstellung einer extrudierbaren Masse, wobei die Kohlenstoffpartikel Partikel aus Kohlenstoffmaterial sind und wobei das Kohlenstoffmaterial Aktivkohle oder Koks ist,
   2. b) Extrudieren der erhaltenen Masse unter Erhalt eines Stranges mit Kanälen,
   3. c) Aushärten des erhaltenen Stranges,
   4. d) Carbonisieren des Stranges oder von Strangabschnitten unter Erhalt von Kohlenstoff-Formkörpern oder Aktivkohle-Formkörpern,
   5. e) Aktivieren der carbonisierten Kohlenstoff-Formköper;
3. III. Imprägnieren des Monolithen durch Tauchen oder Durchleiten der Imprägnierlösung;
4. IV. Trocknung des Monolithen.

A method according to the invention for producing a respiratory protection filter from a rigid activated carbon material, wherein the respiratory protection filter as a monolithic molded body comprises a plurality of channels that are not connected to one another and which are arranged in parallel and the channels are covered with at least one metal compound, has the following steps:

1. I. Preparation of the impregnation solution, the impregnation solution being prepared by dissolving ammonium chloride, zinc carbonate and sodium molybdate in a 25% ammonia solution with stirring and with slight warming, [see exemplary embodiments];
2. II. Providing the monolith, comprising the following steps a) to e):
   1. a) mixing carbon particles and at least one binder to produce an extrudable mass, wherein the carbon particles are particles of carbon material and wherein the carbon material is activated carbon or coke,
   2. b) extruding the mass obtained to obtain a strand with channels,
   3. c) hardening of the strand obtained,
   4. d) carbonizing the strand or strand sections to obtain carbon molded bodies or activated charcoal molded bodies,
   5. e) activating the carbonized carbon molded bodies;
3. III. Impregnating the monolith by dipping or passing the impregnation solution through;
4. IV. Drying the monolith.

1. I. Ansetzen der Imprägnierlösung wobei das Bereitstellen der Imprägnierlösung erfolgt, indem Ammoniumchlorid, Zinkcarbonat und Natriummolybdat unter Rühren und bei leichter Erwärmung in einer 25% Ammoniaklösung gelöst werden,;
2. II. Bereitstellen des Monolithen, umfassend die folgenden Schritte a) bis e):
   1. a) Vermengen von Kohlenstoffpartikeln und zumindest einem Bindemittel unter Herstellung einer extrudierbaren Masse, wobei die Kohlenstoffpartikel Partikel aus Kohlenstoffmaterial sind und wobei das Kohlenstoffmaterial Aktivkohle oder Koks ist,
   2. b) Extrudieren der erhaltenen Masse unter Erhalt eines Stranges mit Kanälen,
   3. c) Aushärten des erhaltenen Stranges,
   4. d) Carbonisieren des Stranges oder von Strangabschnitten unter Erhalt von Kohlenstoff-Formkörpern oder Aktivkohle-Formkörpern,
   5. e) Aktivieren der carbonisierten Kohlenstoff-Formköper;
3. III. Imprägnieren des Monolithen durch Tauchen oder Durchleiten der Imprägnierlösung;
4. IV. Trocknung des Monolithen.

The respiratory protection filters according to the invention comprise a rigid activated carbon material, in particular monolithic in nature, are equipped as molded bodies with a plurality of non-interconnected channels arranged in parallel, the channels being covered with metal compounds and produced by a method that has the following steps

1. I. Preparation of the impregnation solution, the impregnation solution being prepared by dissolving ammonium chloride, zinc carbonate and sodium molybdate in a 25% ammonia solution with stirring and with slight warming;
2. II. Providing the monolith, comprising the following steps a) to e):
   1. a) mixing carbon particles and at least one binder to produce an extrudable mass, wherein the carbon particles are particles of carbon material and wherein the carbon material is activated carbon or coke,
   2. b) extruding the mass obtained to obtain a strand with channels,
   3. c) hardening of the strand obtained,
   4. d) carbonizing the strand or strand sections to obtain carbon molded bodies or activated charcoal molded bodies,
   5. e) activating the carbonized carbon molded bodies;
3. III. Impregnating the monolith by dipping or passing the impregnation solution through;
4. IV. Drying the monolith.

Monolithic means that the shaped activated carbon body is made from one piece without deformation (apart from cutting) as a whole body, e.g. by extrusion.

Activated charcoal moldings with a large number of parallel channels have the advantage that they enable the user of respiratory protection filters to use a respiratory protection mask with reduced breathing resistance compared to masks with conventional gas filters and thus enable long, fatigue-free use of the respiratory protection.

The respiratory protection filters according to the invention can be used directly as filter bodies due to their mechanical stability. A complex housing, which would have to be disposed of with the filter material, can be dispensed with. A simply designed insert on a mask, for example, makes it possible to remove the adsorber from the mask and dispose of it. The slide-in unit has a seal. The respiratory protection filter can be encapsulated with small amounts of plastic for better dimensional accuracy in the insert. By attaching the insert directly to the mask, the field of vision can be significantly improved, and the filter on the gas mask only offers low mechanical points of attack, which improves work safety, e.g. in narrow areas.

The respiratory protection filters according to the invention have a very homogeneous structure due to their defined geometry and are characterized as a filter medium in respiratory protection systems such as respiratory masks by a low pressure drop with a high adsorption capacity. The impregnation of the activated charcoal moldings according to the present invention with impregnation solutions enables the production of activated charcoal moldings for protection against e.g. ABEK gases in respiratory protection filters.

In addition to the standard-compliant protective effect, such a respiratory protection filter surpasses all previously known low pressure drops and is therefore hardly noticeable for wearers of respiratory protective devices, in particular respiratory masks, or requires only a fraction of energy in fan-assisted respiratory protection technologies. In portable respiratory protection systems, this enables the use of performance-optimized batteries, which is an additional noticeable advantage for the user.

The carbon particles are particles of carbon material, any other constituents of which pyrolyze during carbonization and are at least partially converted into carbon. The carbon material can be activated carbon or coke made from a wide variety of starting materials, for example from wood, peat, stone fruit kernels, nutshells, coconut fibers, plastics, hard coal coke and / or lignite coke.

The activation takes place e.g. by gas activation or chemically. During gas activation, the material is exposed to a temperature of 800-1000 ° C in an oxidizing gas stream such as water vapor, carbon dioxide, air or mixtures of these gases. When manufacturing with chemical activation, the material is treated at 500-900 ° C with chemicals such as dehydrating agents (e.g. zinc chloride, phosphoric acid) or by dry distillation. The crude activated carbon obtained in this way is then oxidatively activated at 700-1000 ° C. with water vapor or carbon dioxide, sometimes also with air.

The extrudable mass can contain further powdery components, such as clays, refractory materials or ceramic materials, but also microspheres, glass fibers and / or carbon fibers. The extrudable mass can also have been produced with the addition of a liquid phase, such as water.

Suitable binders are water glasses, e.g. with amorphous powdered silicon dioxide, phenolic resins such as resols or novolaks, furan resins, epoxy resins or polyester resins or mixtures thereof.

When manufacturing the monolithic activated charcoal moldings by extrusion, the viscous hardenable masses are continuously pressed out of a shaping die under pressure. The activated carbon adsorber is obtained as a strand which is then cut into appropriate lengths as required.

Another type of production of the shaped body consists in applying or applying the activated carbon composition in a planar manner with a corrugated structure, and shaping these surfaces into an activated carbon shaped body by rolling them up. One such method is in the WO 2011/041144 A2 described. This is a non-monolithic embodiment.

The shaped activated carbon body contains channels which are aligned parallel to one another, in particular essentially parallel to the longitudinal axis of the shaped activated carbon body or rotated relative to one another. The channels preferably extend completely through the shaped activated carbon body with openings on the end faces. Each channel opening on one end face preferably corresponds to a channel opening on the other end face without the channels being connected to one another. The shaped activated carbon body can be in the form of a cuboid or a cylinder, for example.

• ― mittlere Kanallängen von 17 bis 150 mm, vorzugsweise 25 mm bis 110 mm,
• ― mittlere Kanaldurchmesser von 0,3 bis 2 mm, vorzugsweise 0,5 bis 1 mm und
• ― mittlere Kanaldichten von 200 bis 800 cpsi, vorzugsweise 400 bis 600 cpsi. cpsi (cells per square inch): wird hier in der Bedeutung von Anzahl der Kanäle pro Quadratinch, auf der Eintrittsfläche bezogen, verwandt.

Activated charcoal moldings which, independently of one another, have:

• - Average channel lengths from 17 to 150 mm, preferably 25 mm to 110 mm,
• - mean channel diameter of 0.3 to 2 mm, preferably 0.5 to 1 mm and
• - mean channel densities of 200 to 800 cpsi, preferably 400 to 600 cpsi. cpsi (cells per square inch): is used here in the meaning of the number of channels per square inch, based on the entrance area.

Thanks to the laminar channels in the shaped activated carbon body, by filling the channels with the impregnating solution, metal compounds can surprisingly be applied or combined, e.g. by immersion or flooding, as a coating of the inner walls of the channel so that their continuity is maintained.

1. 1. Ansetzen der Imprägnierlösung,
2. 2. Bereitstellen des Monolithen,
3. 3. Imprägnieren des Monolithen durch Tauchen oder Durchleiten der Imprägnierlösung, und
4. 4. Trocknung des Monolithen.

The impregnation takes place, for example, by at least the following steps

1. 1. Prepare the impregnation solution,
2. 2. Provision of the monolith,
3. 3. Impregnating the monolith by dipping or passing the impregnation solution through, and
4. 4. Drying the monolith.

According to one embodiment, the activated carbon (impregnation) is coated with zinc and molybdenum at least in the area of the channels of the monolithic activated carbon adsorber. The impregnation is preferably carried out with a metal compound soluble in water or in an aqueous ammonia solution, such as a zinc and molybdenum compound, e.g. by stirring and dissolving zinc carbonate, ammonium chloride, ammonium carbonate and sodium molybdate. The monolithic activated carbon body is impregnated with such an impregnation solution and carefully dried, e.g. by warm / hot air, until the water content of the impregnated monolith is below 3 m% (m% = mass percent, also referred to as mass compartment (w)).

• - Zink-Verbindung (A1) mit Molybdän-Verbindung (B),
• - Kupfer-Verbindung (A2) mit Molybdän-Verbindung (B),
• - Silber-Verbindung (A3) mit Molybdän-Verbindung (B).

The following combinations of adsorbents are particularly preferred:

• - zinc compound (A1) with molybdenum compound (B),
• - copper connection (A2) with molybdenum connection (B),
• - Silver connection (A3) with molybdenum connection (B).

Combinations of A1 + A2, A1 + A3, A2 + A3, or even all members A1-A3 with B are also possible. Preferred is A1 + B, A2 + B or A1 + A2 + B.

Copper carbonate (especially basic) is preferably used as the copper compound. The impregnation or impregnation solution is preferably chromium-free.

It is also possible to use several differently coated activated carbon adsorbers one behind the other so that the breathing air flows through them one after the other.

• • 1 bis 8 m% Zink,
• • 0,1 bis 2,5 m% Molybdän,
• • 1 bis 10 m% Kupfer und/oder
• • 0,1 bis 2 m% Silber.

wobei vorzugsweise und auch unabhängig von der Konzentration der Metallverbindung weiterhin zumindest eines der folgenden Anionen: Chlorid, Phosphat und deren Gemische, und insbesondere in nachfolgenden weiter bevorzugten Konzentrationen auf dem Träger vorhanden ist:

• • 0,2 bis 6 m% eines Chlorids, berechnet als Cl, oder
• • 1 bis 12 m% eines Phosphats, berechnet als Phosphorsäure.

The respiratory protection filter preferably has the metal compound individually and in combination in the following concentration (calculated based on the metal):

• • 1 to 8% zinc,
• • 0.1 to 2.5 m% molybdenum,
• • 1 to 10 wt% copper and / or
• • 0.1 to 2% silver.

where preferably and also independently of the concentration of the metal compound, at least one of the following anions: chloride, phosphate and mixtures thereof, and in particular in the following more preferred concentrations, is also present on the carrier:

• • 0.2 to 6% by mass of a chloride, calculated as Cl, or
• • 1 to 12 wt% of a phosphate, calculated as phosphoric acid.

According to one embodiment, the respiratory protection filters according to the invention are part of respiratory masks, the face part of which encapsulates the respiratory organs from the ambient air by the face part lying sufficiently close to the face.

If the mask is to be worn for longer periods of time without undue discomfort, the face piece is designed to be soft and flexible. If the respirator works with exchangeable filters, the filter typically consists of a filter element that is built into a housing. The coupling of the housing containing the filter element with the breathing air inlet of the respiratory protection mask takes place by means of an adapter, with which the housing for the filter element is typically received at the same time in a complementary housing on the face part. The respiratory protection filters according to the invention can, however, also be used directly, i.e. without a complementary housing. The respiratory protection masks can, for example, be designed as full face masks or half masks that only enclose the mouth and nose.

Furthermore, the respiratory protection filters according to the invention can be used in closed and semi-closed breathing circuits, which are used to enable the user to breathe completely or partially independent of the ambient air. This is the case, for example, with working circuit devices of fire brigades, for pits, but also escape devices, diving devices or submarines. By guiding the breathing air in the circuit, breathing gas can be saved. For this it is necessary to reduce the carbon dioxide and other pollutants produced and exhaled by the user.

Test examples:

Chemicals used: 25% aqueous ammonia solution CAS 1336-21-6 Ammonium chloride CAS 12125-02-9 Zinc carbonate CAS 3486-35-9 Sodium molybdate CAS 10102-40-6

Impregnation solution 1:

163.1 g of ammonium chloride, 235.1 g of zinc carbonate and 69.1 g of sodium molybdate were dissolved in 1771.4 g of a 25% ammonia solution with stirring and with slight warming (approx. 35-40 ° C.).

Impregnation solution 2:

163.1 g of ammonium chloride, 235.1 g of zinc carbonate and 69.1 g of sodium molybdate were dissolved in 971.4 g of a 25% ammonia solution with stirring and with slight warming (approx. 35-40 ° C.).

Impregnation solution 3:

163.1 g of ammonium chloride, 235.1 g of zinc carbonate and 69.1 g of sodium molybdate were dissolved in 1314.3 g of a 25% ammonia solution with stirring and with slight warming (approx. 35-40 ° C.).

Impregnation and drying:

A monolithic shaped activated carbon body with the dimensions approx. 50 x 50 x 110 mm (400 cpsi) (weight approx. 95 g each) was completely immersed in one of the impregnation solutions 1 to 3 for 5 minutes. The still dripping wet monolith was then freed from excess impregnating liquid with a blast of compressed air and air at 160 ° C. flowed through it at a volume flow of approx. 85 L / min for approx. 30 min. The monolith treated in this way showed an increase in weight (loading) as a result of the impregnation after drying, as can be seen from Table 1. The water content of the monolith was about 2.5 m% after drying.

Gas test:

The impregnated monoliths were glued in a gastight manner using sealing compound in housings, which in turn had an RD40 round thread connection, and gas adsorption was tested. The results of the service lives obtained are compiled in Table 1. Tab. 1 Impregnation solution Weight gain Downtimes for C ₆ H ₁₂ Cl ₂ H ₂ S HCN SO ₂ NH ₃ G min min min min min min 1 7.3 70 25th 35 19th 20th 39 2 15.6 39 83 89 58 39 98 3 12.5 73 74 50 47 27 88

The test was carried out in accordance with EN 14387: 30 L / min, 20 ° C, 70% RH, at 1000 ppm harmful gas, the resistance of the monolith (dimensions see above) was under these conditions in all cases less than 25 Pa (measured in accordance with EN 14387 ). This is 3 to 4 times better than with comparable gas adsorption filters for breathing air.

Claims (11)

A method for producing a respiratory protection filter from a rigid activated carbon material, wherein the respiratory protection filter comprises, as a monolithic molded body, a multiplicity of channels which are not connected to one another and which are arranged in parallel, and the channels are covered with at least one metal compound, and wherein the method has the following steps: I. Preparation of the impregnation solution, the impregnation solution being prepared by dissolving ammonium chloride, zinc carbonate and sodium molybdate in a 25% ammonia solution with stirring and with slight warming; II. Providing the monolith, comprising the following steps a) to e): a) mixing carbon particles and at least one binder to produce an extrudable mass, the carbon particles being particles of carbon material and the carbon material being activated carbon or coke, b) extruding the mass obtained to obtain a strand with channels, c) hardening of the strand obtained, d) carbonizing the strand or strand sections to obtain carbon molded bodies or activated charcoal molded bodies, e) activating the carbonized carbon molded bodies; III. Impregnating the monolith by dipping or passing the impregnation solution through; IV. Drying the monolith. Procedure according to Claim 1 , wherein step IV. comprises the sub-steps a) removing excess impregnating solution from the dripping wet monolith with a blast of compressed air and b) flowing hot air through the monolith. Respiratory protection filter, characterized in that the respiratory protection filter is produced according to a method according to one of the preceding claims, the shaped body having a pressure drop of 25 Pa and less when breathing air flows through it. Respiratory protection filter according to Claim 3 , comprising at least one metal compound in each case in the following concentration (based on the metal): 1 to 8 wt% zinc, 0.1 to 2.5 wt% molybdenum and / or 1 to 10 wt% copper. Respiratory protection filter according to at least one of the Claims 3 or 4th , further comprising at least one of the following anions: chloride, phosphate and mixtures thereof, preferably • 0.2 to 6 wt.% of a chloride, calculated as Cl, or • 1 to 12 wt.% of a phosphate, calculated as phosphoric acid. Respiratory protection filter according to at least one of the Claims 3 until 5 , wherein the channels are additionally covered with an inorganic acid, in particular after application of the metal compound, in particular with phosphoric acid. Respiratory protection filter according to at least one of the Claims 3 until 6th , whereby the channels are not covered with chrome or a chrome compound. Respiratory protection filter according to at least one of the Claims 3 until 7th having, independently of one another, a) an average channel length of 17 to 150 mm, preferably 25 mm to 110 mm; b) an average channel diameter of 0.3 to 2 mm, preferably 0.5 to 1 mm; and / or c) an average channel density of 200 to 800 cpsi, preferably 400 to 600 cpsi. Breathing protection mask having at least one breathing air inlet having at least one breathing protection filter according to at least one of the Claims 3 until 8th . Respirator after Claim 9 The respiratory protection filter used from the molded activated carbon body does not have an additional housing. Use of the respiratory protection filter according to at least one of the preceding Claims 3 until 8th as part of a breathing mask for filtering breathing air or in a closed or semi-open breathing circuit device.