Molecular sieve abstract
A molecular sieve material is combined with a porous carrier material.
The pores of the molecular sieve material are impermeable to molecules
or organisms having a size equal to or greater than that of the
water molecule either because the molecular sieve material is selected
so as to have pores which are smaller than such molecule or because
the pores of the molecular sieve material are closed by a film.
The pores of the molecular sieve material thus remain unoccupied
and are able to exert an attractive force on molecules or organisms
which are to be captured. The pores of the carrier material are
designed to accept molecules or organisms having a size equal to
or greater than that of the water molecule so that, when such molecules
or organisms are attracted by the molecular sieve material, they
can be trapped in the carrier material.
Molecular sieve claims
I claim:
1. A filter substance for the removal of a selected constituent
from a fluid containing a plurality of constituents, said substance
comprising a carrier material having first pores; and a molecular
sieve material having second pores, said second pores being smaller
than said first pores and too small to permit entry of the selected
constituent thereinto and being bounded by internal surfaces which
generate an attractive force for attracting the selected constituent
to, and holding the selected constituent in said first pores, and
said molecular sieve material being selected or designed to substantially
prevent accumulation of any constituent of the fluid on said internal
surfaces.
2. The substance of claim 1 wherein said materials are bound to
one another.
3. The substance of claim 1 wherein said second pores have a size
smaller than 3 Angstroms and said first pores have a size larger
than 3 Angstroms.
4. The substance of claim 3 wherein said molecular sieve material
comprises a zeolite of the analcite group.
5. The substance of claim 3 wherein said second pores have a size
of approximately 2.6 Angstroms.
6. The substance of claim 1 wherein said materials constitute
part of a composite and are bound to one another, said composite
being fibrous.
7. The substance of claim 1 wherein said materials constitute
part of a composite and said composite is in the form of at least
one ingestible tablet.
8. The substance of claim 1 wherein said carrier material is heat-resistant.
9. The substance of claim 1 wherein said first pores are channel-like.
10. A filtering method, comprising the steps of contacting a fluid
with a filter substance containing a porous carrier material and
a porous molecular sieve material having internal surfaces which
generate an attractive force; drawing a selected constituent of
said fluid into said carrier material using said attractive force;
and substantially preventing accumulation of any constituent of
said fluid on said internal surfaces.
11. The method of claim 10 wherein said selected constituent comprises
a multiplicity of molecules.
12. The method of claim 10 wherein said selected constituent comprises
a multiplicity of microscopic particles.
13. The method of claim 10 wherein said fluid comprises blood
or blood plasma and said selected constituent includes bacteria
or a virus.
14. The method of claim 10 wherein said fluid comprises stomach
juices and said selected constituent includes microscopic particles,
bacteria or a virus.
15. An article of manufacture, comprising a base member; and a
filter substance for the removal of a selected constituent from
a fluid containing a plurality of constituents, said substance applied
to said base member and including a carrier material having first
pores, and a molecular sieve material having second pores, said
second pores being bounded by internal surfaces which generate an
attractive force for attracting the selected constituent to, and
holding the selected constituent in said first pores, and said molecular
sieve material being selected or designed to substantially prevent
accumulation of any constituent of the fluid on said internal surfaces.
16. The article of claim 15 wherein said base member comprises
a textile.
17. The article of claim 15 wherein said base member is selected
from the group consisting of mats, handkerchiefs, baby napkins,
bandages and operating cloths.
18. The article of claim 15 wherein said base member comprises
an ingestible capsule.
19. A composition of matter, comprising a base substance; and a
filter substance for the removal of a selected constituent from
a fluid containing a plurality of constituents, said filter substance
including a carrier material having first pores, and a molecular
sieve material having second pores, said second pores being bounded
by internal surfaces which generate an attractive force for attracting
the selected constituent to, and holding the selected constituent
in said first pores, and said molecular sieve material being selected
or designed to substantially prevent accumulation of any constituent
of the fluid on said internal surfaces.
20. The composition of claim 19 wherein said base substance comprises
a liquid, paste or cream and said filter substance is incorporated
in said base substance to form a hygroscopic composite.
21. Molecular sieve arrangement for the filtration of molecules
or microscopic particles from gases and liquids, comprising a granulated
or particulate molecular sieve material which has channels and primary
pores and is bound in a porous carrier material, the primary pores
of the molecular sieve material being constituted in such a manner
that adsorption and absorption of water and gas molecules are prevented
and no direct loading occurs at the inner surfaces of the molecular
sieve material, the molecular sieve material having a pore size
greater than 3 Angstroms, and the pores and channels of the molecular
sieve particles or granulate being closed at the surface by a film
or skin which is impermeable to water molecules.
22. The molecular sieve arrangement of claim 21 wherein the film
or skin consists of metal.
23. A filter substance for the removal of a selected constituent
from a fluid containing a plurality of constituents, said substance
comprising a carrier material having first pores with a size larger
than 3 Angstroms; and a molecular sieve material having second pores
with a size smaller than 3 Angstroms, said second pores being bounded
by internal surfaces which generate an attractive force for attracting
the selected constituent to, and holding the selected constituent
in said first pores, and said molecular sieve material being selected
and designed to substantially prevent accumulation of any constituent
of fluid on said internal surfaces.
Molecular sieve description
BACKGROUND OF THE INVENTION
The present invention relates to a molecular sieve arrangement.
Natural and synthetic zeolitic molecular sieves are suitable for
the separation of mixtures of inorganic and organic substances and
for the removal of undesired impurities from gases and liquids.
One current field of application of molecular sieves is the drying
of gases and liquids, for example, acetone, butane, toluene, etc.
Molecular sieves are also used for the removal of carbon monoxide,
hydrocarbons, nitrogen, methane and so on from air. They are further
used in ion exchangers.
Molecular sieves within the scope of the invention can consist
of natural or synthetic zeolites. Synthetic zeolites frequently
have the same crystal structure as natural zeolites. Natural zeolites
may, for example, be aluminum silicates having the general formula
##EQU1## where Me denotes the alkali metal ion (n=1), mostly Na
or K, or the alkaline earth metal (n=2) which is normally Ca and
more seldom Ba, Sr and Mg. Most of the ad/absorbents are included
in this category.
The mechanics of separating molecules from liquid or gaseous media
by means of molecular sieves involves adsorption with the molecular
sieve functioning as an adsorbent and influencing the adsorption
through the magnitude and energy characteristics of its surface.
The adsorption of ions, molecules or molecular agglomerates and
the like--the adsorbates--is limited by the energy characteristics
of the boundary layer between the two phases. The adsorbed molecules
continuously coat the inner surface of the adsorbent and cover the
same. Accordingly, saturation occurs after a certain amount of time
and prevents further adsorption.
The known separating processes use only molecular sieves having
a pore size of 3 Angstroms or greater than 3 Angstroms in order
to permit the entry of molecules to be filtered out of gases or
liquids, that is, in order to make the vast inner surface of the
molecular sieve usable.
The zeolites of the natural analcite group, whose pores have a
size of the order of 2.6 Angstroms, have not been used as molecular
sieves because the molecules to be adsorbed or absorbed cannot,
due to their size, penetrate into the primary pores of the analcite
zeolite. The smallest molecule, which is the water molecule, measures
only about 2.9 Angstroms (see "MOLEKULARSIEBE" by Otto
Grubner, Pavel Jiru and Milos Ralek, VEB Deutscher Verlag der Wissenschaften,
Berlin 1968 page 27).
The disadvantageous property of the known molecular sieves is that
the inner surfaces thereof are directly loaded and, depending upon
molecular sieve type, no further molecules can be taken up once
the adsorbate proportion has increased to about 25%.
Loading of the inner surfaces of the conventional molecular sieves
already occurs upon contact with the surrounding air and the water
molecules contained therein. Accordingly, the capacity is reduced
in two respects.
SUMMARY OF THE INVENTION
The invention here provides a remedy.
The invention, solves the problem of creating a molecular sieves
arrangement which can filter molecules or microscopic particles
from gases or liquids and in which the inner surfaces of the molecular
sieve can be coated neither by water molecules nor by the filtered
molecules.
A molecular sieve which is incorporated in a carrier material and
has a pore size smaller than 3 Angstroms (primary pores) allows
the molecules or particles to be filtered to be brought into the
pore and channel structure of the carrier material; the inner surfaces
of the molecular sieve having pores smaller than 3 Angstroms remain
largely free and retain their static charge (Coulombic attraction).
The pore and channel structure of the carrier material can have
cross sections which are larger than the pores of the molecular
sieve by a factor of up to 1000 and more. Correspondingly larger
quantities of particles to be filtered can be accumulated in these
relatively vast inner cavities before the static attraction of the
adsorbent is no longer sufficient to draw additional charged particles
into the channel structure of the carrier material. Water present
in the carrier material, which can serve as a transporting medium,
is successively pushed out of the channels by charged particles
to be accumulated. The capacity thus depends, for one, on the attractive
forces of the zeolitic material; the particle size of the accumulated
charged particles has no significant influence on the quantitative
capacity.
Hence, this mechanism favors highly polar particles, e.g., viruses;
molecules having lower values can again be pushed out of the channel
structure and through the surface pores of the carrier material.
A selection, which is controlled by appropriate choice of the channel
cross sections and surface pores of the carrier material, that is,
by the secondary pore structure and channel structure, accordingly
also becomes possible. Due to the possibility of placing zeolites
having pores smaller than 3 Angstroms and constituting part of the
molecular sieve arrangement according to the invention directly
in aqueous media, viruses or stimulating agents in general can be
filtered out of liquids, e.g., blood or blood plasma.
For use in blood, the composite material of adsorbent and porous
carrier material is preferably preloaded with water so that no water
but only particles capable of being caught by polar effects can
be removed from the medium to be filtered. For use in gaseous media,
the carrier material cavities can be preloaded with an inert gas.
A further advantage of the composite material of the invention
is the energy saving during desorption of the adsorbate. Since the
accumulated particles are stored only in the channel structure of
the carrier material and are not adsorbed on the inner surfaces
of the zeolitic material, a regeneration or rinsing out can be accomplished
with substantially less energy and, consequently, also at lower
temperatures. The choice of the carrier material is thereby simplified,
that is, synthetic resins, e.g., in the form of fibers as carrier
materials, having a large surface area and, accordingly, superior
dynamics, can also find application as reusable composite materials.
Adsorbents which are smaller than 3 Angstroms and are incorporated
in non-combustible, porous carrier materials, e.g., stone, pumice,
clays, porous metals, etc., can be used for the purification of
exhaust gases from combustion machines. Here, regeneration by washing
is possible.
In another advantageous embodiment of the invention, similar results
can be achieved using conventional zeolites whose pores are larger
than 3 Angstroms and are agglutinated, for example, if zeolite pores
larger than 3 Angstroms are covered and closed by a film or skin
which is impermeable to water molecules to thereby prevent the entry
of water molecules. The skin can consist of metal, e.g., aluminum.
The inherent attractive force of the zeolites or molecular sieves
can thus not be nullified by water molecules accumulated in the
channel structure of the carrier material. The ad/absorption forces
of the molecular sieve particles having pores larger than 3 Angstroms
remains in existence as in the zeolites with pores smaller than
3 Angstroms.
In comparison to activated carbon, the composite material according
to the invention accordingly exhibits substantially greater dynamics
and capacity, lower energy consumption during desorption (regeneration)
and, in addition, better stability as regards shape. In the form
of capsules or tablets, the composite material can be ingested instead
of activated carbon, e.g., to take up particles such as viruses,
bacteria and the like present in stomach/intestinal juices. By including
hard magnetic additions in the composite, the composite and the
trapped particles can be readily separated after travelling through
a conveying section in the medium to be purified.
The greatest dynamics of the product according to the invention
are achieved in the form of fibers since these have a very large
surface area per unit weight and yet, in the form of a fleece, for
example, can be readily handled in liquid and gaseous media.
In the form of fiber clippings to which another component has been
added, the material of the invention can be brought into circulation,
e.g., in the blood vessels of a living being, and subsequently again
removed from circulation by suitable means, e.g., magnetic fields
if the other component is magnetically engageable. Since the other
component preferably does not have an attractive force itself, agglomerates
in the circulatory path can be avoided.
By incorporating the composite material of the invention in liquids,
salves or cremes which are preferably hygroscopic, access of stimulating
agents to wounds can be prevented and, at the same time, stimulating
agents present at the wound can be removed therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is more fully described with reference to specific
embodiments illustrated in the accompanying drawings wherein:
FIG. 1 shows a greatly enlarged fiber having zeolites incorporated
therein,
FIG. 2 shows a synthetic killer cell (in the form of a fiber clipping)
enlarged about ten thousand times,
FIG. 3 is a section through a fiber having zeolite particles with
a pore size greater than 3 Angstroms (loaded),
FIG. 4 is a section through a fiber having zeolite particles with
a pore size smaller than 3 Angstroms (unloaded), and
FIG. 5 is an enlarged illustration of a pore or channel in a fiber
according to FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a section of a fiber 1 in which zeolites 2 are
incorporated in the form of an ultrafine powder or granulate. The
incorporation of the zeolites 2 in the carrier structure, that is,
in the material of which the fiber 1 is made, is not the subject
of this invention. There are various possibilities for adding the
zeolite component 2 during the spinning process for the fiber 1.
The fiber 1 itself consists of a material with an open pore structure.
This allows the take-up and release of water and water vapor. Fibers
1 without zeolites 2 and capable of taking up water vapor are known;
a method for the production of such a fiber 1 is described, for
example, in European patent application 0 029 949 and in the publication
Chemiefasern/Textilindustrie, 31/82 pages 112-116 (1981).
When zeolite particles 2 with primary pores larger than 3 Angstroms
are incorporated in such a fiber 1 whose pores 3 and channels 4
have a cross section of approximately 1000 nm, then this can be
used to filter from the environment particles such as viruses, bacteria
and molecules which can penetrate into the carrier material through
the pores (secondary pores) 3 on the surface thereof and are drawn
by the attractive forces of the zeolites 2. Since the water molecules
of approximately 2.9 Angstrom size are always smaller than the (primary)
pores of an incorporated conventional zeolite of 3 Angstrom size
or greater than 3 Angstrom size and arrive at the inner surfaces
of the zeolites 2 via the primary pores, the effectiveness of the
zeolites 2 in the free atmosphere or in a liquid medium is low because
of rapid loading with water molecules.
Due to the accumulation, i.e., adsorption, of molecules through
its primary pores 13 the attractive force of a grain of conventional
molecular sieve granulate decreases steadily and rapidly in the
free atmosphere until a maximum loading, namely, approximately 25
percent by weight, is achieved.
If now, in accordance with the invention and as illustrated in
FIGS. 4 and 5 zeolites 2 having a pore size smaller than 3 Angstroms,
e.g., 2.6 Angstroms, are incorporated in the fiber 1 then the molecules
and particles 5 etc., entering through the channels 4 of a porous
fiber 1 can penetrate only to the vicinity of the incorporated zeolite
particles; entry into the primary pores 13 in contrast, is not
possible. Even the water molecule 6 is unable to load the primary
pores (diameter of 2.6 Angstroms, for example) of zeolites of the
analcite group (see FIG. 5). In this manner, the attractive force
of the zeolites 2 is mostly retained and the secondary pore structure
of the carrier material, which is preferably selected so as to have
sizes in the nanometer/micron range, takes up and holds a very large
quantity of particles and molecules, as well as bacteria, viruses
and the like, capable of being caught by polar effects. The attractive
force of the zeolite crystals remains high even with loaded carrier
material channels so that particles having high polarity values
can diffuse through the channel structure which is, for example,
loaded with water. The corresponding proportion of water is pushed
outwards. Further loading is terminated only when an equilibrium
is reached between adsorbent and adsorbate. If the zeolitic material
is bound in plastics, then the alkaline zeolitic material (pH value
approximately 11.5) can also be used in substances susceptible to
alkalis since direct contact with the medium to be purified, e.g.,
in the nutrient and hygienic fields, is now prevented. Suitable
carrier materials for this purpose are polyamides and polyacrylics,
for example, as well as activated carbon; also soil and metals for
applications requiring resistance to heat.
The mechanism according to the invention can also be closely achieved
with conventional zeolites 2 having pores larger than 3 Angstroms
in that the pores 13 are covered or closed by a film or skin so
as to be sealed against water molecules. The inherent attractive
force of the zeolites or microsieves can then no longer be annulled
by accumulated water molecules in the channel structure of the carrier
material. As in the zeolites having pores smaller than 3 Angstroms,
the ad/absorption forces remain operative.
As already indicated above, it now becomes possible, by way of
example, to separate bacteria having a size of 2 microns, for instance,
or viruses having a size between about 8 and 400 nm, for example,
from liquids or the gas phase. The viruses, in particular, have
a highly charged surface and are thus drawn into the (secondary)
channel structure of the carrier material by the charge of the adsorbents
bound in the carrier material. Since water molecules cannot enter
the primary pores of the zeolite, the viruses are held back in the
channel structure of the carrier material. The water molecules are
subsequently again successively pushed out of the channel structure
of the carrier material via the surface pores thereof by the particles
drawn to the zeolite. The water accordingly functions as a transporting
medium. It becomes possible to draw and accumulate the most diverse
particles, bacteria and viruses, as well as pesticides, from the
environment by means of a carrier material which has been preloaded
with water.
It is possible, for example, to manufacture a mouth and nose protector
having a fleece which is made of fibers and the molecular sieve
arrangement of the invention and which constitutes a filter against
the penetration of viruses, bacteria and so on to thereby prevent
infections via the respiratory tract (influenza, colds, adeno-infections,
corona infections and viral infections) as well as other infections
(smallpox, rubella, chicken-pox, mumps, measles, etc.). By means
of the mentioned filter, viruses bound to the drops which are generated
upon sneezing are caught and held back.
The textile fiber, cotton wool or fleece according to the invention
can be used as a cotton wool plug, as a protective breathing mask
or as a filter in ventilating and air conditioning systems.
Since, due to incorporation in a porous carrier material, the alkaline
properties of the zeolitic material no longer affect the substances
to be purified, it is possible to purify blood and plasma from particles
such as bacteria, viruses, etc. in that the blood and plasma are
passed through a tube filled with appropriately prepared fiber material
and, after passage, are again conveyed to the human or animal body.
If hard magnetic metallic material, e.g., (MeCO.sub.3 +FeO.sub.3),
is additionally mixed with the composite, then the composite particles,
e.g., in the form of fiber clippings, circulating in the liquid
to be purified can be localized and once again separated. These
fiber clippings accordingly have the action of a killer cell which
catches particles (viruses, bacteria, etc.) swimming along therewith
in the liquid. Such a killer cell can, for instance, consist of
fiber clippings produced from porous material and having the molecular
sieve arrangement in accordance with the invention. The pores (primary
pores) of the synthetic zeolite crystal have a diameter of less
than 3 Angstroms, e.g., 2.6 Angstroms. The synthetic fiber exhibits
a pore structure having a diameter of 1000 nanometers, for example.
The fiber clipping itself has a diameter of about 8 microns and
a length of 8 to 10 microns which is a size approximating that of
a T4 helper lymphocyte. As already indicated above, MeCO.sub.3 and
FeO.sub.3 can, for instance, be added as hard magnetic material
and can take the form of oxidized or sintered material which has
been ground to a particle size of about 0.2 micron.
These fiber clippings can be placed in a liquid, e.g., the circulatory
system or preserved blood plasma, and again separated after a certain
amount of time by means of magnetic fields.
A fibrous fleece material of the same composition as the fiber
clippings which contain the hard magnetic particles (and are thus
capable of being caught) can be used for separation. The fibrous
fleece material is, however, additionally magnetized and holds back
the magnetically engageable fiber clippings flowing through the
same.
Use is possible not only in organic liquids but also for the filtration
of liquid nutrients. If necessary, the fibers/fiber clippings are
here preloaded with water under sterile conditions prior to use.
The just described synthetic killer cells can be used for the isolation
of known and unknown stimulants/virus types if these are extracted
from the composite material by vacuum techniques, for example, after
passage through the circulatory system. It is self-understood that
synthetic killer cells can also be locally inserted in the lymphatic
system. For a better understanding of the size relationships, FIG.
2 shows a synthetic killer cell at an enlargement of about ten thousand
times.
Aside from the described applications in the trapping of viruses,
bacteria and the like, the composite material can be used in an
appropriate form, e.g., with a heat-resistant material such as clay,
etc., for the purification of exhaust gases from combustion engines,
e.g., at the outlet of the muffler or as a separate interchangeable
part.
Filters made of the composite material according to the invention
can also be used in air conditioning and ventilating systems of
buildings and vehicles, as well as in household vacuum cleaners,
and make it possible to filter out not only dust particles but also
stimulants (viruses, bacteria, etc.) detrimental to health since
the zeolitic material component with primary pores of approximately
2.6 Angstroms is not directly loaded, and its action is not cancelled,
by the omnipresent water molecules.
An application is also possible as a lining in shoes to prevent
the accumulation of spores which can result in a foot fungus.
There further exists the possibility of using the composite material
for the drying of air in the air brakes of vehicles whereby, as
compared to the conventional zeolitic granulate with a primary pore
size of 3 Angstroms and up, it is possible to achieve an approximately
fourfold increase in moisture capacity or to operate with a substantially
smaller volume.
Another area of application is in insulating glass spacers, e.g.,
where fibers made of the composite material are in the form of a
plait.
Inserts produced from the composite material and provided in the
closures of containers or on the inner surfaces thereof function
to protect the contents against moisture or to dehydrate the contents.
A further application of fibers made from the composite material
of the invention is in the production of filter mats, operating
cloths, handkerchiefs, baby napkins and other hygienic articles.
The fibers worked into the handkerchief material (cellulose) remove
particles such as viruses, etc. which adhere to the moisture applied
to the material. The usual spreading of infection via the handkerchief
upon reuse is thus very greatly reduced. Analogously, other cloths,
as well as tampons, in the hygienic field can be enriched with the
fiber of the invention.
In large industrial installations, the composite material can be
used to filter out pesticides and the like contained in water. As
already mentioned earlier, a regeneration of the filter composite
material can be achieved with little energy consumption.
Another possibility for use of the composite material is in the
binding of viruses on plants. If the composite material in the form
of fiber clippings is mixed with fruit wax, for example, and applied
to plants by spraying, then the plants are protected against stimulants,
e.g., tobacco mosaic bacilli and viruses from tobacco plants. |