IE940736A1

IE940736A1 - Method and materials for the decontamination of polluted¹rooms

Info

Publication number: IE940736A1
Application number: IE940736A
Authority: IE
Inventors: Hasso Von Blucher; Dr Ernest De Ruiter; Dr Jost Heiner Kames; Jonas Tornblom
Original assignee: Bluecher Hasso Von; Ruiter Ernest De
Priority date: 1993-09-17
Filing date: 1994-09-16
Publication date: 1995-03-22
Also published as: ITMI941883A0; EE9500070A; AU684307B2; NL194752B; CN1114825A; GB9418767D0; SE9501839L; NL194752C; JPH08506762A; NO951940L; SI9420004A; HU9501768D0; JP3285873B2; HRP940542A2; GB2282982B; HUT72859A; CZ125295A3; LU88532A1; WO1995007735A1; NL9420007A

Abstract

The invention relates to a method for decontaminating polluted rooms and to suitable materials therefore. The method for combating the emission of odorants and pollutants is characterized in that the emission source is directly covered with a material containing adsorbent particles. Furthermore, the invention relates to an absorbent material, containing a flat-shaped support material; which forms a water-vapor permeable barrier layer, or on which an additional water-vapor permeable barrier layer is located; and a layer located on said support material, containing adsorbent particles.

Description

The invention relates to a method of decontaminating polluted rooms and to suitable materials therefore.

With increasing environmental consciousness and highly sensitive analytical methods, the public is becoming more aware of the environmental impact caused by harmful matter. There exists an increasing need for decontaminating buildings polluted by harmful matter (pollutants) or odorants with as little expenditure as possible. Furthermore, one recognized the necessity for determining the presence of harmful matter by simple means to be able to consider the necessity and success of an eventual rehabilitation. The expression harmful or pollutant as used in this context, embraces substances that can cause irritations, allergies and illnesses in humans, even when present in small amounts. This includes, for example, wood preservatives, such as pentachlorophenol (PCP) and lindane, plasticizers, such as polychlorinated biphenyls (PCB) or also formaldehyde, the latter was used in chipboards and is now suspected to be cancerogenic. Also hydrocarbons, which may also be aromatic, and their chlorinated derivatives can escape as harmful matter from, for example, lacquers, paints or adhesives.

Particularly problematic substances are PCB, which were used as plasticizers in joint sealants, especially in the construction of buildings from prefabricated elements. New findings have shown that with time the PCB diffuse from the sealant into adjacent concrete elements and are also liberated from the sealant into the ambient air. The PCB-polluted air is distributed over the entire building via air circulation. The PCB thusly liberated from the joint packings, the so-called primary sources, settle in the rooms, partly bonded to small particles but also dissolved to a large extent in wall paints and plastic materials. The result is that after being liberated for some time, a number of so-called --^rces are forme A further source of harmful matter and odorants is carpeting. The emissions are produced in that, for example, the starting materials of these products react under the influence of moisture and/or the influence of components of the base material. The floor further emits odorants and harmful matter even after the removal of the flooring material and therefore so far necessitates either the removal of the entire flooring or laying a false floor with rear ventilation.

A further source of unpleasant emissions, which are sometimes detrimental to the health, are additives added to the building material itself. For example, lots of buildings are contaminated with ammonia exhalations originating from the use of ammonium salts, urea or organic amines, in a broader sense, as antifreezing compounds for concrete and mortar. Furthermore, another reason for the exhalation of amines may be the previous use of a room, for example, for purposes of livestock husbandry, causing harmful matter to settle on building elements over a long period of time. If the sources of these substances are removed, for example, if a stable is converted into a living room or an office, the substances will be remitted from the secondary sources i.e., walls and ceiling surfaces. This situation is comparable to the abovementioned problem of PCB pollution, both in respect of its cause and effect.

DE-A-38 18 993 teaches a method of decontaminating polluted rooms. However, in this case, the polluted ambient air is purified. This is done by passing air by means of suitable measures over adsorbents, either by applied means or by natural circulation. For example, the polluted air is pressed through adsorption towers loaded with adsorbents. Another possibility described therein consists in passing the -3air over large surfaces loaded with adsorbents, such as curtains. However, a decisive disadvantage of this method is that it is only effective in respect of the polluted ambient air. This results in that the purified air is repeatedly mixed with the polluted air so that, at best, a dilution effect is achieved.

A possibility of disposal of harmful matter-containing joint sealants is described in DE-OS 40 28 434. By applying appropriate measures, the sealant, i.e. the primary source, is cut off and disposed of. However, the method is effective only in respect of the primary source. As already described above, the harmful matter from the secondary sources, i.e. the wall and ceiling surfaces, also pollutes the ambient air to a critical extent; the secondary sources cannot be decontaminated with this above-mentioned method.

The object of the present invention is to create a method of decontaminating polluted rooms. This problem is solved by directly covering the emission source with a material containing adsorbent particles. The main advantage is that by selecting appropriate materials according to the invention, the penetration of the pollutants through the covering layer and hence a transfer of the latter to the ambient air is prevented. By decontaminating the polluted emission sources, the method of the present invention sets in a step earlier than the prior art methods. Thus, the method of the present invention already inhibits the transfer of the pollutants to the ambient air and the formation of secondary emission sources right from the beginning, whereas all the hitherto described methods are based on the measure of removing harmful matter from the polluted ambient air.

The complete covering of the emission source, as suggested by the invention, has two decisive advantages: harmful matter is not transmitted to the environment and the adsorption takes place where the concentration of noxious matter is highest. 4By virtue of the method of the present invention, the radon concentration in inhabited buildings could be reduced to such an extent that threshold limit values serving as precautionary measure for protection of public health could be observed.

An embodiment of the method of the present invention consists in additionally covering elements or articles adjacent to the primary emission sources with materials containing adsorbent particles. This covering is intended to inhibit the escape of harmful matter entailed by the diffusion of the pollutants from the primary emission sources into said adjacent elements and, in case of migration to the surface of said elements, their escaping into the ambient air.

In a further embodiment of the present invention, the material is selected from the group consisting of open-pored foam materials, nonwoven fabrics and inorganic and organic binders. It is in particular an open-pored foam material, preferably a reticulated PU foam, having a thickness of from 0.5 to 5 mm and containing finely-ground adsorbent particles and a binder. The material may as well consist of a nonwoven fabric having a thickness of from 0.1 to 2.0 mm and containing the adsorbent particles and the binder. According to a further embodiment of the invention, the material may be a coating, a cast, a sound absorbing cast or floor finish containing the adsorbent particles.

According to the invention, the material containing the adsorbent particles may as well be a wall-to-wall carpeting, preferably a back-side coating of carpetings.

The term binder or binding agent as used herein includes all substances which connect substances of the same kind or different substances to each other. Thus, in the case of a cast according to the invention, they may be, for example, all non-hydraulic, hydraulic and potentially hydraulic binders (plaster stone, water glass, Sorel’s cement, magnesia cement, white lime, hydraulic lime, cement, Hast fur-5nace slag etc.). In the case of the open-pored foam materials and nonwoven fabrics, the binders are, for example, all natural or synthetic materials that are used as solutions, dispersions, molten masses or liquid reactive plastic systems after confection (for example, by suitable resins and plasticizers, occasionally also pigments and fillers) for bonding different kinds of materials.

As to the use of a cast or a floor finish for the purposes of the invention, preferably those compositions have proved to be advantageous which simultaneously serve for sound-proofing cast. One reason for this behavior might be the high porosity which at the same time allows a good accessibility to the adsorbent. The cast is usually delivered as dry mixture with up to 50 percent by weight of adsorbent particles and is prepared to form a paste prior to use. Likewise, the floor to be decontaminated can be covered according to the method of the invention with an additional floor finish containing up to 50 percent by weight adsorbent particles.

A further embodiment of the claimed method consists in that the adsorbents may also be incorporated into a tapestry paste. This adhesive can, for example, consist of a 40 %-ethylacrylate dispersion to which 60 percent by weight of ground activated carbon forming a slurry with water are added. Walls and ceilings can be coated with a layer having a thickness of 300 micrometers and a conventional tapestry can be applied on this layer. The adhesion is good.

If one uses hydrophobic molecular sieves as adsorbents, a white ground shade is obtained to which any kind of coloring pigments can be added. An effective control of the thickness of the layer remains important to avoid local weak points by insufficient amounts of adsorbents.

Instead of the tapestry paste, the adsorbents can also be incorporated into a paint which in that case has to be applied thick enough. For -6reasons of outer appearance, one will hardly use activated carbon to this end but molecular sieves. Paints are useful especially when irregular and non-planar bodies (cables, tubes) or cuts are to be covered. In preparing materials for the method of the invention, one should be careful that the binder does not contain substances that can be adsorbed by the adsorbent particles. The expert in this field knows suitable solutions that need not be further illustrated here. However, it is recommendable to confirm the choice of binding agent by a blank test.

A further embodiment of the method of the present invention is that the material comprising the adsorbent particles is a wall tapestry having applied thereon a reticulated 1mm to 5 mm PU foam loaded with adsorbent particles. Foams of the kind are preferably squeezed off with a mixture of ground activated carbon and a dispersion of a binding agent and dried. In this case, a carbon loading of up to 200 g/m2 is achieved, the binding agent/carbon ratio of 1:1 to 1:5, based on the dry substance, may vary.

A further embodiment of the invention consists in that the material containing the adsorbent particles is a support layer made of a flatshaped support material selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth, and the adsorbent particles are applied on this support layer. Preferably, this support layer forms together with the particles applied thereon a test strip which is deposited on the covered or uncovered building elements to determine the penetration of pollutants through barrier layers or to determine the exit of pollutants.

A flat-shaped support material suitable for the method of the present invention, containing activated carbon spherulets is described in the European patent applications 118 618 and 90 073. -7These test strips of the present invention can be located with the adsorbents either outwardly or inwardly in respect of the emission source to trace out, for example in the latter case, cuts through a tapestry exhibiting adsorption properties or through flooring materials exhibiting adsorption properties. A strip of 20 mm x 100 mm, containing about 0.5 g of activated carbon, has proved to be very useful and handy. One embodiment of the invention consists of a double adhesive tape having one surface thereof loaded with adsorbent particles and the other surface covered with siliconized protective paper that has to be pulled off prior to use. The strip is packed in a gasproof cover which protects the activated carbon until it is used and serves for the return delivery to the analytical laboratory. The strips can be applied, for example, on the bottom side of chairs, tables etc. by light pressure and can be easily removed therefrom.

A further application of these test strips is to control the decontamination of polluted buildings which will be illustrated by an example. As already described above, an all-over contamination of walls and ceilings by vaporization of PCB in buildings made of prefabricated elements may occur, which can be neutralized by covering the contaminated surface by tapestry containing activated carbon. In this case, it would be useful to recognize in good time an eventual escape of the PCB through the tapestry. To this end, the test strip with the adsorbent particles pointing towards the wall is pasted on the surface of the adsorbent tapestry. When doing so, an adhesive tape overlapping the test strip is preferably used (1 cm overlap on all sides) such that the adsorption layer is not in contact with the adhesive. The surface pointing towards the interior can additionally be provided with a barrier layer, for example, an aluminum foil, in order to increase the efficiency of the strip.

In respect of the decontamination of a flooring or flooring material, another embodiment of the invention teaches to lay between the contaminated flooring or flooring material and the new carpet or any -8other new flooring material a layer or a material that can adsorb the odorants and the harmful matter. To conduct this method, granular or spherical adsorbents, preferably activated carbon, but also porous polymers, are ,for example, made to adhere on a flexible support material by means of an adhesive composition printed on in a punctiform fashion and are covered with a slightly air-permeable textile material. A flat-shaped support material containing activated carbon that is suitable for the purposes of this invention is described in EP-A 118 618 and EP-A 90 073A further possibility is to provide the support with a coating pervious to water vapor which acts as adhesive composition for the adsorbents. The adsorbents are dusted into said coating; after drying, the so-obtained layer of adsorbents is covered with a light textile fabric. By virtue of the all-over coating, an additional barrier layer is incorporated in addition to the adsorption layer, said barrier layer allowing the flooring to breathe due to its permeability to water vapor. The use of an adsorbent which is not part of the carpeting, allows to subsequently lay any kind of carpeting on said material. The adsorbents may also be directly applied on the carpeting. To do so, it is necessary to provide a high-quality backside coating which serves at the same time as adhesive composition for the adsorbents. This backside coating can additionally be covered by a light textile fabric. If this method is adopted, the accessibility of the adsorbents is at least 50 %, preferably between 70 % to 80 %. This is advantageous in respect of the adsorption kinetics since a migration through the adhesive layer does not take place. In comparison thereto, activated carbon which, for example, is incorporated into the backside coating in the form of a powder is less efficient because of the reduced accessibility of the outer surface.

A further embodiment of the method of the present invention consists in the material containing the adsorbent particles, being a composite material consisting of a support layer of a flat-shaped support material „9selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth; a layer located on said support layer and containing the adsorbent particles; and a cover layer applied on said layer containing the adsorbent particles. Thus, this composite material has a sandwich structure comprised of support layer, adsorbent particles and cover layer. The adsorbent particles are preferably applied on the support layer by means of a preparation containing an adhesive composition. The adhesive composition consists of organic binding agents, in particular a dispersion of plastic material or a low-solvent two-component system, or is selected from the group of lattices, for example, natural latex. This preparation which contains the adhesive composition can either be applied in a punctiform or as all-over coating. Since for constructional physical reasons, the water- and air-permeability of the materials used in construction plays an important role, the adhesive composition should be permeable to water vapor, in particular if the coating is applied all-over the surface.

The cover layer used for the materials that can be utilized according to the method of the present invention is a flat-shaped support material selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth. This cover layer can preferably be laminated on the material containing the adsorbent particles by fusion adhesive-points or a thin web of fusion adhesive.

A composite material that can be used according to the method of the present invention can be prepared, for example, as follows: the support pointing towards the inner space (textile fabric, special paper or glass cloth) is provided with a water vapor-permeable all-over coating which is at the same time the adhesive for the granular or spherical adsorbents. The coating is dusted with the adsorbents prior to drying. The excess is sucked off. The adsorption layer is subsequently covered, for example, by a light textile to protect it from the adhesive - 10 material by means of which the composite material is adhered to the building element. Light-weight fine-meshed non-woven polyesters with a printed-on fusion adhesive are particularly suitable as cover.

The over-all coating has the important advantage that even if a loosely woven textile support is used, the latter can be coated by preventing the wall paint from contaminating or damaging the adsorbents or otherwise impairing the accessibility of the pollutants being adsorbed thereon. Dispersions that are suitable for preparing water vapor-permeable coatings are, for example, the Plextols of Rohm GmbH, Darmstadt or Impranils or Impraperm types of Bayer AG.

Another possibility of protecting the adsorbent particles in the material used according to the method of the invention against the penetration of the paint is the following structure: the support layer of the adsorbers points towards the wall and the adsorbers themselves are covered by the outer material, a fusion adhesive-slit film being used as adhesive coat between the adsorbers and the outer material. It is ensured thereby that sufficient moisture can penetrate, but not the paint. However, either low-solvent paints or free-solvent paints should preferably be used for the coating.

In a further embodiment of the invention, an additional barrier layer, preferably a water vapor-permeable barrier layer, is located on the surface pointing away from the emission force, i.e. on the support layer or the cover layer.

Furthermore, the invention relates to an adsorbent material, containing a flat-shaped support material which forms a water-vapor permeable barrier layer and a layer located on said support material, containing adsorbent particles. In a further embodiment according to the invention this adsorbent material furthermore contains an additional cover layer deposited on said layer containing the adsorbent particles. - 11 A further adsorbent material according to the invention present in the form of a composit material contains a flat-shaped support material; an additional water-vapor permeable barrier layer, located on said support material; and a layer containing adsorbent particles deposited on said barrier layer. In a further embodiment, this adsorbent material furthermore contains an additional cover layer located on said layer containing the adsorbent particles.

The function of the barrier layer is to increase the contact time between the harmful matter and the adsorbents by retarding the migration rate of the harmful matter from the emission source towards the surface of the composite material. A further advantage of the barrier layer is to inhibit the migration of not easily volatized permanently absorbable gases from the ambient air into the adsorption layer which would otherwise reduce the adsorption capacity, e.g. vis a vis radon escaping from the wall. It is preferably applied when porous air-permeable flat-shaped fabrics are used as support. A support layer of the kind is appropriately water vapor-permeable in order not to prevent the breathing of the walling.

The barrier layer can at the same time be the adhesive composition for the adsorbent particles. Moreover, the barrier layer can consist of a slit film laminated on the inner surface of the composite material’s outer layer, preferably of a fusion adhesive-slit film, which is connected to the adsorbent particles on the other side. In a further embodiment, the barrier layer may consist of a latex coating or a latex paint applied on the outer surface of the composite material pointing towards the room.

As to the adsorption of radon according to the method of the present invention, the use of a diffusion adhesive-slit film as barrier layer, by means of which the outer cover layer pointing towards the room was laminated on the adsorption layer, has proved to be very efficient. Depending on the laminating temperature, the penetration of air is -12reduced by about 90 % while at the same time the radon adsorption is basically improved. The moisture penetration is more than satisfactory and consequently a risk of accumulation of moisture in the walling does not exist. A further method of radon adsorption created by the invention consists in the use of a specific material, where the backside of the outer material is provided with a water vapor-permeable coating which simultaneously serves as adhesive layer for the adsorbent particles or spherules. Thereafter, a cover is laminated on the adsorber layer obtained after the coating process, said cover may be, for example, a textile or a paper. In both of the above-mentioned cases, the radon first comes into contact with the adsorption layer. That portion of the radon which is not completely adsorbed hereby, runs into the barrier layer and is retarded thereby so that the adsorption process can continue.

In a further embodiment of the method and of the absorbent materials of the present invention, the surface of the material or composite material pointing towards the emission source (support or cover layer) is a separating layer designed to allow a removal of the composite material in such a manner that the latter can be removed from the emission source and can be disposed of. The removal means in this context that especially the adsorbent particles being connected with the separating layer can be removed, and that completely, from the emission source. This separating layer may preferably be a split paper or a split nonwoven fabric or it may consist of two easily separable non-woven fabrics.

Applicants’ tests have shown that in the case of adsorption of PCB on activated carbon, due to the favorable adsorption equilibrium, the PCB can be sucked off the emission source (for example, a contaminated wall) such that the wall becomes almost free of PCB within a few years. In this connection, the particular job of the separating layer is, for example, to allow to pull down in a simple manner a wall tapestry from an emission source, so that the same can be disposed of in an -13appropriate manner, for example, by incineration of hazardous wastes. The PCB-containing adsorbents should be completely accessible and collected. To this end, a weak point (a predetermined breaking point) should be incorporated into the composite material of the support and the tapestry. This possibility is offered by the following illustrative structure: the textile outer material carries on the side pointing towards the wall grains of adsorbents which adhere to the textile material by means of a discontinuously applied adhesive material. The adsorbents themselves are covered with a split paper. Split papers have a relatively well-glued surface but are hardly glued interiorily and are therefore splitable. When they are pulled down, the one half remains on the wall and can serve as base for a new tapestry, while the other half continues to cover the adsorbents; thus a loss of adsorbents is completely avoided.

A further possibility of removing for example a tapestry without a loss of adsorbents consists in adapting the cover of the adsorbents pointing towards the wall to be strong enough to resist breakage when the tapestry is pulled down. It is preferable to moisturize the adhesive base first.

In general, an advantage of the above-described composite material is that the harmful matter can move freely within the adsorption layer until its adsorption. If due to a particular structure of the emission source, the liberation of harmful matter is more pronounced here and there, the latter can laterally expand freely in the adsorption layer due to the barrier layer and the sandwich structure (no local overstress). A large amount of adsorbents is always available in all directions which allow a uniform distribution of the pollutants. If a sealing is effected without applying any adsorbents, for example, with an aluminum foil, migration effects and massive escape will occur.

In contrast, small local damages of the composite material of the present invention, e.g., by drilled holes, is completely harmless be- 14 cause the action of the adsorptive tapestry for example is based on the bonding of the pollutants in the neighborhood of the emission source and does not rely on an all-over insulation.

A further embodiment of the method of the invention consists in that the materials containing the adsorbent particles are present in the form of strips which, for example, are placed over the joints sealed with a sealant containing the pollutant or are pressed into said joints. Preferably, these strips can be covered again with a material which is suitable for the method of the present invention to ensure with absolute certainty that harmful matter does not escape into the room. Since, in general, the joint sealant is placed in a recessed position, there is enough room for a thick strip of adsorbent material; larger amounts of adsorbent particles can be accommodated in this cavity whereby safety can be guaranteed, even after many years.

The adsorbent particles used according to the method and the material of the invention are activated carbon powder, activated carbon spherules, activated carbon grains, carbonized and activated ion-exchangers, spherical pitch coal, hydrophobic molecular sieves, hydrophobic molecular sieve moldings or porous polymers. The adsorbent particles, in particular the activated carbon, have an inner surface of at least 900 m^g. The activated carbon spherules and grains preferably have a diameter of from 0.1 mm to 2.0 mm, in particular from 0.3 mm to 1.0 mm. Preferably, the adsorbent particles are present in an amount of from 5 g/m2 to 400 g/m2, in particular from 10 g/m2 to 250 g/m2.

The manufacture of carbonized and activated ion-exchangers is described in DE-A 43 04 026. The materials of the present invention contain, in general, up to 70 percent by weight of adsorbent particles.

Numerous methods lend themselves for applying the adsorbent panicles, for example on the support material. As described, for example -15in DE-A 32 11 322, a paste comprising activated carbon and a binder dispersion is printed on in heaps by means of a rotary screen-print; whereby coatings of up to 100 g/m2 can be obtained. The use of spherical activated carbon which is made to adhere to a textile fabric by a composition applied in a punctiform fashion is described in DE-A 33 04 349An adsorbent that is particularly suitable for the purposes of the present invention is spherical pitch coal. Thus, if spherical coal having a diameter of from 0.3 mm to 0.8 mm is used, up to 1000 spherules per cm2 can be applied on the support material of the test strips or the composite material of the present invention. This corresponds to more than 20 mg/cm2 of activated carbon which is practically accessible since the adhesive composition closes only 10 % to 15 % of the pores. Having an inner surface of from 1000 to 1200 rnVg and a micropore volume of 0.3 ml/g and a pore diameter of from 0.5 nm to 1.2 nm, basically from 0.8 nm to 0.9 nm, the spherical coal is particularly suited for the purposes of the invention. It is important that the micropores are relatively narrow to ensure maximum adsorption forces. On the other hand, the micropores must be large enough to be able to adsorb the pollutant molecules which are not so small, for example, the PCB molecules. Pore diameters of from 0.6 nm to 1.0 nm are therefore very advantageous. Pore diameters of the kind are found, for example, in activated carbons based on pitch (spherical coal), based on coconut shell and based on specific hard coal. Pollutants are strongly adsorbed in these materials and are durably held therein.

A homogenous loading of the support layer containing the adsorbent particles is important for the efficiency of the composite material. It is guaranteed especially if spherical activated carbon is used. -16Beside the spherical coal, also granular coal or salty coal (having a particle size of from 0.3 mm to 2 mm) can be basically used. However, spherical coal is preferred due to its smooth abrasion-resistant surface and the optimum adsorption achieved therewith.

To adsorb specific pollutants, it could prove necessary to impregnate the adsorbent particles and to use various kinds of adsorbent particles: for example pure activated carbon for pollutants having a high boiling point, for example, PCB and PCP; pure activated carbon, preferably with very small micropores, for solvents; acid-impregnated activated coal, for example, with phosphoric acid, to adsorb ammonia and amines; base-impregnated activated carbon, for example with potassium carbonate, for acidic gases; coal impregnated with 2-amino1,3-propanediol to adsorb formaldehyde; sulfur-impregnated coal to adsorb mercury vapors: copper salts-impregnated activated coal to adsorb sulfur-containing and nitrogen-containing pollutants; to mention only the most important.

With regard to the escape of ammonia from a walling, it has proved particularly efficient to apply tapestry containing phosphoric acid-impregnated activated carbon particles. A tapestry of the kind has basically the above-described sandwich structure, granular and spherical adsorbents being placed between two flat-shaped fabrics of textile or paper, one being the support layer for the adsorbents and the other the cover layer for the adsorbents. To adsorb pollutants having a high boiling point according to the method of the present invention, porous polymers, such as the XUS resins of the DOW Chemical company, can also be employed. Likewise recommendable are carbonized and activated cation exchangers, comprising mainly sulfonated styrene/divinyl benzene-copolymers, which are very similar to the activated carbon in respect of their physical properties. -17For the purposes of the invention, at least 50 % , in particular between 75 % and 80 %, of the outer surface of the adsorbent particles should preferably be accessible to the pollutants and the odorants.

The emission sources to be decontaminated by the method or the materials of the present invention are building elements and building materials containing in particular odorants and harmful matter, such as, for example, walls, bearing elements, prefabricated walls, concrete slabs, floors, ceilings, wooden beams, wooden floors, joints, sealants, primers and joint sealants.

Harmful matter in the sense of the present invention involves pollutants that can be adsorbed in particular on activated carbon powder, activated carbon spherules, activated carbon grains, carbonized and activated ion-exchangers, spherical pitch coal, hydrophobic molecular sieves, hydrophobic molecular sieve moldings, and/or porous polymers. Pollutants belonging to this class are in particular polychlorinated phenols (PCP), polychlorinated biphenyls (PCB), chlorinated hydrocarbons (CHC), polycondensed aromatic compounds (PAK), chloroparaffins, phthalates, amines, 2-ethylhexanol, ammonia and radon.

Example 1 The inner walls of a building built with prefabricated elements which were contaminated by being exposed for many years to PCB-polluted ambient air, were all-over coated with a dispersion adhesive for heavy-weight tapestry. A filter sheet material as taught in EP-A-118 618, consisting of a glass fabric tapestry loaded on one surface thereof with about 210 g/m2 of activated carbon spherulets having a diameter of 0.5 mm with the aid of punctiformly applied adhesive material and covered with knitted textile fabric, was embedded in an adhesive bed. After conducting these measures, the PCB concen-182 tration in the ambient air was reduced from about 10,000 ng/m to below 300 ng/m3 and remained thereafter under this value. The covering material made the impression of a textile tapestry.

Example 2 The material used according to the invention, containing adsorbent particles, consisted of noise prevention slabs which were loaded at the surface pointing towards the wall with granular activated carbon having a diameter of 0.55 mm to 1.2 mm and a bearing weight of 190 g/m2. The further process steps were the same as in the preceding examples. By virtue of the over-all covering, the PCB concentration could likewise be reduced to below 300 ng/m .

Example 3 As cover material, a carpet covering the entire floor, the back-side of which was loaded with activated carbon spherules, was fixed to a PCB-contaminated concrete floor. The escape of PCB could completely be prevented.

Example 4 A polyester fabric web having a basis weight of about 100 g/m2 on which were adhered about 200 g/m2 of spherical coal (average diameter: 0.55 mm) was cut into strips which overlapped the joints to be covered on both sides by 1.5 cm. The strips were fastened by adhesive tapes whereon the tapestry was located, which on its part, was loaded with 200 g/m2of spherical coal. -19Example 5 Siliconized protective paper was divided into three parts on an adhesive tape having a width of 10 cm: in strips having a width of 7 cm, and left and right 1.5 cm respectively (1.5 cm + 7.0 cm + 1.5 cm = 10 cm). The middle strip of protective paper was progressively pulled off, and the adhesive layer with the spherical coal of Example 4 was simultaneously dusted thereon, which adhered at once. The strip loaded with spherical coal could be rolled up without any problem. The lateral protective papers were pulled off at the place of operation and the strips were applied in such a manner that the coal layer overlapped the joint by about 1.5 cm. Tapestry was laid on this strip as in Example 4.

Example 6 A web of a reticulated large-pored PU foam having a width of 1 cm (weight per liter 30 g, porosity 15 ppi) was thoroughly loaded with an adhesive material (Impranil HS 62 + Imprafix HSC, 30 g/1). 200 g of spherical coal/I foam material were subsequently charged in a vibrator. After removing the excess and the thermal curing of the adhesive composition, the web was cut into strips having a width of 4.5 cm and the latter were pressed into the joints having a width of 4 cm. The strips were fixed with an adhesive tape as fixing device. Tapestry was placed over these strips as in Examples 4 and 5.

Example 7 The PU foam, as used in Example 6, was loaded with a paste consisting of ground activated carbon, water and a binder dispersion and was freed from excess paste in a squeezer. After drying the fabric -20web, the latter was cut into strips and further processed as indicated in Example 6. A typical paste preparation is as follows: activated carbon: 315 g (dry) water: 435g acrylate binder A (soft): 40 g acrylate binder B (hard): 80 g thickening agent solution (4 % in water): 100g lubricant (based on polyamide): 15g The methods of the invention as described in examples 4 to 7 were applied to decontaminate PCB-polluted sealants in buildings made of prefabricated elements. Having applied the method according to the invention in these examples, no PCB could be detected at the outer surface of the cover.

Analogous tests on a laboratory scale have shown that as described in the examples, hydrophobic molecular sieves can be used instead of activated carbon.

As shown in the aforegoing examples, emissions of pollutants, such as PCB can be pronouncedly suppressed by the method of the present invention and can also be completely inhibited. As compared to the prior art passive collectors, the method of the invention allows a practically 100 % direct adsorption of harmful material diffusing from the emission source. In particular, pollutants having a high boiling point are permanently fixed. Applicants’ tests have shown that pollutants are definitively adsorbed up to an amount of 10 percent by weight, based on the adsorbent particles. Thus, a coal amount of 200 g/m.2 can durably render harmless up to 20 g/m2 of pollutant. Since such amounts never occur in practice, the activated carbon is never exhausted.

Claims

1. A method for combating the emission of odorants and pollutants, characterized in that the emission source is directly covered with a material containing adsorbent particles.

2. A method according to claim 1, characterized in that the elements or articles directly adjacent to the emission sources are additionally covered all-over with materials containing the adsorbent particles.

3. A method according to claim 1 or 2, characterized in that the material containing the adsorbent particles is selected from the group consisting of open-pored foams, non-woven fabrics and inorganic or organic binding agents.

4. A method according to claim 3, characterized in that said material is an open-pored foam having a thickness of from 0.5 to 5 0 mm, preferably a reticulated PU foam containing finely ground adsorbent particles and a binding agent.

5. A method according to claim 3, characterized in that said material is a non-woven fabric having a thickness of from 0.1 to 2.0 mm, containing finely-ground adsorbent particles and a binding agent.

6. A method according to claim 3, characterized in that said material is a paint, a cast, a sound-absorbing cast or a floor finish containing adsorbent particles.

7. A method according to claim 3, characterized in that said material is a wall-to-wall carpeting containing adsorbent particles, preferably a backside coating of carpetings.

8. A method according to any of claims 3 to 7, characterized in that said material contains up to 70 % by weight of adsorbent particles. -229- A method according to any of claims 1 or 2, characterized in that the material containing the adsorbent particles is a support layer consisting of a flat-shaped support material selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth; and in that the adsorbent particles are applied on said support layer.

9. 10. A method according to claim 9, characterized in that the support layer and the adsorbent particles applied thereon form a test strip which is applied to determine the escape of environmental poisons through barrier layers or to determine the exit of environmental poisons and their deposition on the material containing the adsorbent particles.

10. 11. A method according to claim 1 or 2, characterized in that the material containing the adsorbent particles is a composite material comprising a support layer of a flat-shaped support material selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth; a layer located on said support layer, containing the adsorbent particles; and a cover layer deposited on said layer.

11. 12. A method according to any of claims 9 to 11, characterized in that the adsorbent particles are applied on the support layer by means of an adhesive composition.

12. 13- A method according to claim 12, characterized in that the adhesive composition is a dispersion of a plastic material, a low-solvent twocomponent system or a latex, e.g. natural latex.

13. 14. A method according to claim 12 or 13, characterized in that the adhesive composition is applied in a punctiform fashion.

14. 15- A method according to claim 12 or 13, characterized in that the adhesive composition is a water vapor-permeable all-over coating. -2316. A method according to any of claims 9 to 15, characterized in that the layer of the material pointing away from the emission source (support or cover layer) forms a water-vapor permeable barrier layer.

15. 17. A method according to any of claims 9 to 15, characterized in that an additional water-vapor permeable barrier layer is located on the surface of the composite material (support or cover layer) pointing away from the emission source.

16. 18. A method according to claim 16 or 17, characterized in that the barrier layer is the adhesive composition for the adsorbent particles.

17. 19- A method according to any of claims 16 to 18, characterized in that the barrier layer consists of a slit film laminated on the inner surface of the outer layer, preferably a fusion adhesive-slit film, which is connected to the adsorbent particles on the other side.

18. 20. A method according to claim 16 to 18, characterized in that the barrier layer is a latex coating, preferably a latex paint, applied on the outer surface pointing towards the room.

19. 21. A method according to any of claims 11 to 20, characterized in that the cover layer is a flat-shaped support material selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth.

20. 22. A method according to claim 21, characterized in that the cover layer is laminated on the material containing the adsorbent particles by means of adhesive points or a web of fusion adhesive.

21. 23. A method according to any of claims 9 to 22, characterized in that the surface of the composite material (support or cover layer) pointing towards the emission source is a separating layer allowing the removal of -24the composite material from the emission source and the disposal thereof.

22. 24. A method according to claim 23, characterized in that the separating layer consists of split paper, split non-wovens or of two easily separable non-woven fabrics.

23. 25. A method according to the preceding claims, characterized in that the adsorbent particles are activated carbon, activated carbon spherulets, activated carbon grains, carbonized and activated ion-exchangers, spherical pitch coal, hydrophobic molecular sieves, hydrophobic molecular sieve moldings or porous polymers.

24. 26. A method according to claim 25, characterized in that the activated carbon has an inner surface of at least 900 m^g.

25. 27. A method according to claim 25 or 26, characterized in that the activated carbon spherulets and the activated carbon grains have a diameter of from 0.1 to 2.0 mm, preferably from 0.3 to 1.0 mm.

26. 28. A method according to any of the preceding claims, characterized in that the adsorbent particles are impregnated, preferably with phosphoric acid, potassium carbonate, trimethanol amine, 2-amino-l,3-propanediol, sulfur or copper salts.

27. 29- A method according to any of the preceding claims, characterized in that the adsorbent particles are present in an amount of from 5 to 400 g/m2, preferably from 10 to 250 g/m2.

28. 30. A method according to any of the preceding claims, characterized in that the materials containing the adsorbent particles are adapted to be strips which are applied on or pressed into the joints sealed with the sealants containing the pollutants. -2531 · A method according to any of the preceding claims, characterized in that at least 50 %, preferably between 75 % and 80 %, of the surface of the adsorbent particles is freely accessible to the pollutant or the odorants.

29. 32. A method according to any of the preceding claims, characterized in that the emission sources are odorants and pollutants-containing building elements or building materials, such as walls, bearing elements, prefabricated walls, concrete slabs, floors, wooden floors, ceilings, wooden beams, wood planks, joints, sealants, primers and joint sealants.

30. 33. A method according to any of the preceding claims, characterized in that the pollutants contained in the emission sources can be adsorbed on the adsorbent particles.

31. 34. A method according to claim 33, characterized in that the pollutants are polychlorinated phenols (PCP), polychlorinated biphenyls (PCB), chlorinated hydrocarbons (CHC), polycondensed aromatic compounds, chloroparaffins, phthalates, amines, 2-ethylhexanol, ammonia or radon.

32. 35. Adsorbent material, containing a flat-shaped support material which forms a water-vapor permeable barrier layer and a layer located on said support material, containing adsorbent particles.

33. 36. Adsorbent material, containing a flat-shaped support material, an additional water-vapor permeable barrier layer located on said support material and a layer containing adsorbent particles deposited on said barrier layer.

34. 37. Adsorbent material according to claim 35, characterized in that it contains an additional cover layer deposited on said layer containing the adsorbent particles. -2638. Adsorbent material according to claim 36, characterized in that it contains an additional cover layer deposited on said layer containing the adsorbent particles.

35. 39· Adsorbent material according to any of claims 35 to 38, characterized in 5 that the flat-shaped support material is selected from the group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth.

36. 40. Adsorbent material according to any of claims 35 to 39, characterized in that the barrier layer is the adhesive composition for the adsorbent par10 tides.

37. 41. Adsorbent material according to any of claims 35 to 40, characterized in that the barrier layer consists of a slit film laminated on the inner surface of the outer layer, preferably a fusion adhesive-slit film, which is connected to the adsorbent particles on the other side. 15

38. 42. Adsorbent material according to any of claims 35 to 41, characterized in that the barrier layer is a latex coating, preferably a latex paint, applied on the outer surface pointing towards the room.

39. 43· Adsorbent material according to any of claims 35 to 42, characterized in that the adsorbent particles are activated carbon, activated carbon 20 spherulets, activated carbon grains, carbonized and activated ion-exchangers, spherical pitch coal, hydrophobic molecular sieves, hydrophobic molecular sieve moldings or porous polymers.

40. 44. Adsorbent material according to claim 43, characterized in that the activated carbon has an inner surface of at least 900 m^g. 25 45. Adsorbent material according to claim 43 or 44, characterized in that the activated carbon spherulets and the activated carbon grains have a diameter of from 0.1 to 2.0 mm, preferably from 0.3 to 1.0 mm. -2746. Adsorbent material according to any of claims 43 to 45, characterized in that the adsorbent particles are impregnated, preferably with phosphoric acid, potassium carbonate, trimethanol amine, 2-amino-l,3-propanediol, sulfur or copper salts. 5 47. Adsorbent material according to any of claims 43 to 46, characterized in that the adsorbent particles are present in an amount of from 5 to 400 g/m2, preferably from 10 to 250 g/m2.

41. 48. Adsorbent material according to any of claims 37 to 47, characterized in that the cover-layer is a flat-shaped support material selected from the 10 group consisting of paper, wall paper or textile fabrics, such as woven fabrics, knitted fabrics, non-woven fabrics or glass cloth.

42. 49- Adsorbent material according to any of claims 37 to 48, characterized in that the cover layer is laminated on the material containing the adsorbent particles by means of adhesive points or a web of fusion adhesive. 15

43. 50. Adsorbent material according to any of claims 35 to 49, characterized in that the surface of the composite material (support or cover layer) pointing towards an emission source is a separating layer allowing the removal of the adsorbent material from the emission source and the disposal thereof. 20

44. 51. Adsorbent material according to any of claims 35 to 50, characterized in that the separating layer is a split paper, split non-wovens or consists of two easily separable non-woven fabrics.

45. 52. A method for combating the emission of odorants and pollutants, substantially as described herein by way of Example. 25 53. Adsorbent material, substantially as described herein by way of Example.