The invention relates to a means of filtration and/or sorption comprising a carbon sorbent.

Background art

Carbon sorbents are used to liquidation of oil accidents from water surface, and there are used both the carbon sorbent in bulk on water surface and carbon sorbent placed in sorption sleeves or sorption plates made of geotextiles. The fine structure imparts the carbon sorbent a great specific surface and with it related adsorption properties utilised in adsorption columns for purification of gases and contaminated waters, for protection of technological sumps and water reservoirs against infiltration of oils, fuels and other hydrocarbons, for anchoring of dangerous substances, for removal of hydrocarbons and their derivatives and for other similar purposes.

Difficult handling with carbon sorbent is a main disadvantage, because the filled bags, sleeves and other formations lack a dimensional stability because the fine granulated sorbent behaves like a liquid. Next to this, the carbon sorbent due to mechanical action disintegrates into fine particles, which cannot be hold by means of a common wrapping material not to penetrate through it and not to permanently pollute everything in their vicinity. The goal of the invention is to reduce or remedy disadvantages of background art.

Principle of the invention

This goal has been achieved by means of filtration and/or sorption according to the invention, whose principle consists in that the carbon sorbent is dispersed in interfibre spaces of voluminous fabric made of intimate fibrous mixture of staple basic fibres and bicomponent fibres, by which the staple basic fibres of voluminous fabric are interconnected and kept in desired position, and also some particles of carbon sorbent are partially fixed by means of bicomponent fibres, while the voluminous fabric is closed in a wrapping comprising a layer of nanofibres arranged between two layers of protective fabric. The wrapping containing the nanofibrous layer prevents penetration of particles of carbon sorbent out of the wrapping, so that vicinity of a filtration and/or sorption means is not polluted at manipulation, but at the same time it enables access for a liquid or gaseous substance which is to be purified. Positioning of carbon sorbent into interfibre spaces of voluminous fabric and their at least partial fixation to bicomponent fibres of such fabric secures an uniform distribution of carbon sorbent in the fabric during its whole service life, and thus also an uniform efficiency of filtration and/or sorption means according to the invention.

It is advantage if the carbon sorbent is formed of carbon composite, which in the advantage embodiment is formed of synthetic soot having specific surface of 20 to 1500 m ² /g.

The quantity of carbon sorbent and/or carbon composite and/or synthetic soot amounts to 50 % by volume of the voluminous fabric. At this volume the properties of the voluminous fabric are conserved and simultaneously also the properties of carbon sorbent, carbon composite or synthetic soot are well utilised.

The voluminous fabric of the means of filtration and/or sorption according to the invention may be produced through aerodynamic forming from a mixture of basic and bicomponent fibres, or through carding of a mixture of basic and bicomponent fibres with subsequent cross laying of fibrous web and hot-air bonding, or through carding of a mixture of basic and bicomponent fibres with subsequent vertical laying of fibrous web and hot-air bonding.

The protective fabric is in advantage formed of a bicomponent spunbond. This enables to obtain high mechanical properties of the wrapping with nanofibrous layer, and simultaneously it simplifies the possibilities of bonding the wrapping by means of heat and pressure. Description of the drawing

Examples of embodiment of the means of filtration and/or sorption according to the invention are schematically represented in the enclosed drawings, where Fig. 1 represents a cross-section of the means of filtration and/or sorption with voluminous fabric produced through vertical laying of fibrous web, Fig. 2 represents a cross-section of the means of filtration and/or sorption with voluminous fabric produced through aerodynamic forming from mixture of basic and bicomponent fibres, and Fig. 3 represents a view to basic fibre and bicomponent fibre.

Examples of embodiment

The basic material for production of the means of filtration and/or sorption according to the invention is a voluminous fabric, formed of staple basic fibres 1, e.g. of polypropylene, and of bicomponent fibres 2, whose core 21 is of polypropylene and the sheath of polyethylene 22. Melting temperature of polyethylene sheath 22 of bicomponent fibres 2 is lower (120 °C) than melting temperature of the core 2J. and than melting temperature of the basic fibres of polypropylene (165 °C). The ratio of basic fibres and bicomponent fibres 2 in the mixture for a voluminous fabric varies from 80 : 20 to 50 : 50, but theoretically only bicomponent fibres 2 may be used. The higher the content of bicomponent fibres 2 in the mixture is, the better the interconnecting of fibres in voluminous fabric is. Also fibres of other materials may be used in the voluminous fabric, however it is necessary to keep a lower melting temperature of the sheath 22 of bicomponent fibres 2 than melting temperature of the core 21 of bicomponent fibres 2 is and than melting temperature of basic fibres is. The staple basic fibres Λ and bicomponent fibres 2 are in the mixture at first thoroughly mixed, usually in a carding machine, into a very uniform so called intimate mixture of fibres. Subsequently the position of fibres is fixed by melting the sheath 22 of bicomponent fibres and subsequent bonding of the bicomponent fibre 2 with surrounding basic fibres Λ . The ratio of fibres in a total volume of the voluminous fabric amounts from 1 to 5 % by volume, in a common embodiment 2 to 3 % by volume, the rest is formed of interfibre spaces.

Carbon sorbent according to the invention is formed of carbon composite, that are the particles of carbon aggregated into a form of chains or clusters, whereas the advantage representative of carbon composites are synthetic soot 3.

Generally the most important feature of synthetic soot is the size of their primary particles and with it related size of surface. Primary particles are of a ball-shaped form and their size varies from 2 to 100 nm, whereas it is valid, that the smaller are the primary particles, the greater is the size of their surface, which varies from 20 to 1500 m ² /g. Another significant characteristics of soot are their structure and size of aggregates. The dimension and complexity of the structure of aggregates is given by a number of the ball-shaped primary particles of soot, which during production process agglomerate into branched chains with many secondary created spaces in an aggregate.

Into the interfibre spaces of the voluminous fabric the particles of carbon sorbent or carbon composite or synthetic soot 3 are transported by some of the known methods, e.g. by shaking-in of carbon sorbent or carbon composite or synthetic soot 3 spilled on a surface of voluminous fabric, or the particles are into the interfibre spaces introduced using the blowing-through applicator, which otherwise serves for applying of powder thermoplastic binder or the particles are introduced into the voluminous fabric at its production through aerodynamic forming of a mixture of basic fibres 1 and bicomponent fibres 2, at which a hot air passes through the voluminous fabric and the sheaths 22 of bicomponent fibres 2 get melted, whereas into this air the particles of carbon sorbent or carbon composite or synthetic soot 3 are introduced by a hot air, which are by this air introduced into the interfibre spaces of voluminous fabric. Particles of carbon sorbent or carbon composite or synthetic soot 3 are into the interfibre spaces of voluminous fabric introduced in a quantity to 50 % by volume. Nevertheless there is not excluded introduction of a greater quantity of carbon sorbent or carbon composite or synthetic soot 3, but the means of filtration and/or sorption with increasing quantity of carbon sorbent or carbon composite or synthetic soot 3 looses the character of a fabric, whereas a sorption ability of the means is increasing. In case that the voluminous fabric or web, of which it will be produced, upon introduction or after introduction of particles of carbon sorbent or carbon composite or synthetic soot 3 is heated above the melting temperature of the sheath 22 of bicomponent fibres 2, at least some of these particles are fixed to the bicomponent fibres 2. The rest of particles of carbon sorbent or carbon composite or synthetic soot 3 are deposited in interfibre spaces of the voluminous fabric.

The voluminous fabric containing particles of carbon sorbent or carbon composite or synthetic soot_3 is subsequently cut into pieces of a required size, which are from all sides covered by a wrapping 4, which comprises a layer of nanofibres 42 arranged between two protective layers 41 of fabric, which is in advantage formed of a bicomponent spunbond and which ensures mechanical properties of the wrapping. The wrapping 4 is connected on edges of the product, e.g. by welding or bonding. The nanofibrous layer 42 inside the wrapping prevents penetration of particles of carbon sorbent or carbon composite or synthetic soot 3 outside of the wrapping 4, so that the vicinity of the means of filtration and/or sorption is not polluted at manipulation with it, at the same time an access of the gaseous or liquid substance being purified into an inner space of the wrapping 4 is enabled and its passage through the voluminous fabric containing particles of carbon sorbent or carbon composite or synthetic carbon particles 3 is enabled.

The voluminous fabric of the means of filtration and/or sorption can be, next to the aerodynamic forming from a mixture of basic and bicomponent fibres, produced also by carding of a mixture of basic and bicomponent fibres with subsequent cross laying of fibrous web and hot-air bonding, or by carding of a mixture of basic and bicomponent fibres with subsequent vertical laying of fibrous web and hot-air bonding, as it is represented in the Fig. 1.

Industrial applicability

The means of filtration and/or sorption according to the invention may be utilised for example as a surface filter into air-conditioning units or as a filtration element for personal protection, e.g. in protective masks, masks or respirators, further as a sorption element for trapping of dangerous or undesired substances from water or air.