Title of Invention

A HIGH CAPACITY SOLID FILTRATION COMPOSITION INCLUDING ITS METHOD OF PREPARATION

Abstract This invention relates to a high-capacity solid filtration composition comprising a permanganate salt having a solubility in water greater than that of potassium permanganate, wherein the concentration of permanganate salt in the composition is 13% to 25% by weight.
Full Text TECHNICAL FIELD
The present invention relates generally to a composition and method for the
removal of compounds having disagreeable odors, toxic properties or corrosive
properties from gaseous streams. The invention more particularly relates to the use in
filter beds of a high capacity solid filtration media containing a substrate impregnated
with a permanganate.
BACKGROUND OF THE INVENTION
The removal of toxic, corrosive and odorous gases can be accomplished by a
number of techniques. These may include wet scrubbing, incineration, and removal
via gas-phase air filtration using a variety of dry scrubbing adsorptive, absorptive,
and/or chemically impregnated media. As opposed to these other methods, gas-phase
air filtration does not require the consumption of large quantities water or fuel. Dry-
scrubbing media can be engineered from a number of common adsorbent materials
with or without chemical additives for the control of a broad spectrum of gases or
tailored for specific gases.
In contrast to the reversible process of physical adsorption, chemical
adsorption, also referred to as chemisorption, is the result of chemical reactions on the
surface of the media. This process is specific and depends on the physical and
chemical nature of both the media and the gases to be removed. Some oxidation
reactions can occur spontaneously on the surface of the adsorbent, however, a
chemical impregnant is usually added to the media. The impregnant imparts a higher
contaminant removal capacity and can lend some degree of specificity. Although
some selectivity is apparent in physical adsorption, it can usually be traced to purely
physical, rather than chemical, properties. In chemisorption, stronger molecular
forces are involved, and the process is generally instantaneous and irreversible.
Undesirable airborne compounds, including sulfur compounds, such as
hydrogen sulfide and dimethyl sulfide, ammonia, chlorine, formaldehyde, urea,
carbon monoxide, oxides of nitrogen, mercaptans, amines, isopropyl alcohol and
ethylene, occur in a number of environments, where most are primarily responsible
for the presence of disagreeable odors, or irritating or toxic gases. Such environments
include petroleum treatment and storage areas, sewage treatment facilities, hospitals,
morgues, anatomy laboratories, animal rooms, and pulp and paper production sites,
among others. These undesirable compounds may be bacterial breakdown products of
higher organic compounds, or simply byproducts of industrial processes.
Hydrogen sulfide ("H2S"), a colorless, toxic gas with a characteristic odor of
rotten eggs, is produced in coal pits, gas wells, sulfur springs, and from decaying
organic matter containing sulfur. Controlling emissions of this gas, particularly from
municipal sewage treatment plants, has long been considered desirable. More
recently, protecting electronic apparatus from the corrosive fumes of these
compounds has become increasingly important. Furthermore, H2S is flammable.
Ammonia ("NH3") is also a colorless gas. It possesses a distinctive, pungent
odor and is a corrosive, alkaline gas. The gas is produced in animal rooms and
nurseries, and its control also has long been considered important.
Chlorine ("Cl2") is a greenish-yellow gas with a suffocating odor. The
compound is used for bleaching fabrics, purifying water, treating iron, and other uses.
Control of this powerful irritant is necessary for the well-being of those who work
with it or are otherwise exposed to it. At lower levels, in combination with moisture,
chlorine has a corrosive effect on electronic circuitry, stainless steel and the like.
Formaldehyde ("OCH2") is a colorless gas with a pungent, suffocating odor. It
is present in morgues and anatomy laboratories, and because it is intensely irritating
to mucous membranes, its control is necessary.
Urea ("OC(NH2)2") is present in toilet exhaust and is used extensively in the
paper industry to soften cellulose. Its odor makes control of this compound important.
Carbon monoxide ("CO"), an odorless, colorless, toxic gas, is present in
compressed breathing air. Oxygenation requirements for certain atmospheres,
including those inhabited by humans, mandate its control.
Oxides of nitrogen, including nitrogen dioxide ("NO2"), nitric oxide ("NO"),
and nitrous oxide ("N2O"), are compounds with differing characteristics and levels of
danger to humans, with nitrous oxide being the least irritating oxide. Nitrogen
dioxide, however, is a deadly poison. Control of pollution resulting from any of these
oxides is desirable or necessary, depending on the oxide.
Mercaptans and amines, including methyl mercaptan ("CH3SH"), butyl
mercaptan ("C4H9SH") and methyl amine ("CH3NH2"), are undesirable gases present
in sewerage odor. The control of these gases is desired for odor control.
Isopropyl alcohol ("(CH3)2CH0H") is a flammable liquid and vapor.
Inhalation of the vapor is known to irritate the respiratory tract. Furthermore,
exposure to high concentrations of isopropyl alcohol can have a narcotic effect,
producing symptoms of dizziness, drowsiness, headache, staggering, unconsciousness
and possibly death. The control of this vapor in print processing and industrial
synthesis is desired.
Ethylene ("C2H4") is a colorless, flammable gas. It is a simple asphyxiant that
accelerates the maturation or decomposition of fruits, vegetables, and flowers.
Control of this compound prolongs the marketable life of such items.
The airborne compounds described above can have a detrimental effect on the
local environment. For example, acidification is caused by emissions of sulfur dioxide
and nitrogen compounds (nitrogen oxides and ammonia), which in turn cause acid
rain. Furthermore, nitrogen oxides and volatile organic compounds from vehicular
traffic, electricity and heat production, as well as from industrial facilities may, under
certain conditions, contribute to the formation of photochemical oxidants, among
which ozone is the dominating substance. Ozone is a colorless gas that forms when
nitrogen oxides mix with hydrocarbons in the presence of sunlight. In addition to
causing environmental damage, ozone poses a health hazard, particularly for children,
the elderly and individuals with asthma or lung disease.
Attempts have been made to provide solid filtration media for removing the
undesirable compounds described above from fluid, or moving, streams, such as gas
or vapor streams. Desired features of such media are a high total capacity for the
removal of the targeted compound so that the media lasts longer and need not be
replaced frequently, a high efficiency in removing the compound from an air stream
contacting the media so that the compound is removed quickly, and a high ignition
temperature (non-flammability). High capacity and high efficiency are, in turn,
directly affected by the porosity and pore structure of the solid filtration media, while
the capacity, efficiency and ignition temperature are all affected by the specific
composition of the media.
Although a variety of permanganate-impregnated substrates are known for
removing undesirable contaminants from fluid streams, these known impregnated
substrates all demonstrate a limited capacity and, therefore, a low efficiency for the
removal of undesirable compounds from the streams. These limitations arise to a
large extent from an insufficient porosity of the solid filtration media or a clogging of
pores with byproducts formed by reactions of the impregnate with the contaminant.
This results in the currently available media not meeting the needs of various
industries.
Therefore, what is needed is a high efficiency, high capacity, low flammability
permanganate-impregnated substrate for the removal of undesirable compounds from
gas streams. Such an impregnated substrate needs to be long-lasting, requiring fewer
replacements and thereby minimizing replacement and maintenance costs. Also
needed is a high capacity impregnated substrate that may be used in small filter beds,
and therefore may allow the treatment of fluid streams where there are significant
space limitations.
SUMMARY OF THE INVENTION
High capacity solid filtration media, methods of preparing the same and
methods of treating a fluid stream with the solid filtration media are provided. The
solid filtration media described herein are useful for removing or reducing
undesirable contaminants from a gaseous fluid stream.
Generally described, the high capacity solid filtration media include a porous,
impregnated substrate having high levels of impregnate. The impregnate is a
permanganate, preferably a permanganate salt having high water solubility, such as
sodium permanganate or lithium permanganate. A gas-evolving or gas-producing
material such as sodium bicarbonate may also be included in the media. In contrast to
presently available filtration media, the high capacity solid filtration media described
herein contain levels of permanganate approximately 8% or higher, thereby providing
an increased efficiency for removing undesirable gaseous compounds from a fluid
stream, particularly compounds such as ethylene, formaldehyde and methyl
mercaptan from gaseous streams by exhibiting a higher capacity for contaminant. For
example, when used to remove ethylene from a gaseous stream, the media described
herein utilizing sodium permanganate have an ethylene capacity of approximately
9%, whereas currently available potassium permanganate-impregnated media exhibit
a maximum ethylene capacity of only approximately 3%.
The present invention addresses an existing need in the industry by providing a
high capacity, low fiammability permanganate-impregnated substrate for the removal
of undesirable contaminants from gas streams. The permanganate-impregnated
substrate provides a long lasting filtration media that can be replaced less frequently,
thereby minimizing maintenance and replacement costs. Due to its high capacity, the
impregnated substrate described herein may be used in small filter beds, thereby
allowing the treatment of fluid streams where significant space limitations exist. The
filtration media described herein yield an equivalent or superior capacity over
activated carbon adsorbents and are much less expensive and considerably less
flammable than activated carbon adsorbents.
Generally described, the filtration media contain at least approximately 8% by
weight of media composition of a permanganate, wherein the permanganate has a
higher solubility in water than that of potassium permanganate, and a porous
substrate, wherein the permanganate impregnates the porous substrate. The
permanganate and the substrate. In yet another aspect, an aqueous solution containing
the permanganate is sprayed onto a dry mixture containing the permanganate and the
substrate. Optionally, sodium bicarbonate may be added either to the dry mixture, to
the water, or to both in the method of preparing the filtration media.
Preferably, the unit formed as described above is cured until the concentration
of water is from about 5 to about 25% by weight of the composition, and the
concentration of the permanganate is from about 8 to about 25% by weight of the
composition. Preferably, where sodium bicarbonate has been added to the
composition, the unit formed is cured until the concentration of sodium bicarbonate is
between 15 to 20% by weight. More preferably, the unit is cured until the
concentration of the permanganate is from about 15 to about 20% by weight of the
composition. Most preferably, the unit is cured until the concentration of the
permanganate is from about 18 to about 19% by weight of the composition.
Yet another aspect of the present invention is a method of treating a
contaminated fluid stream with the high capacity solid filtration media described
herein. This method comprises contacting the contaminated fluid stream with the
solid filtration media to remove contaminant.
The high capacity filtration media, the method of preparation, and the method
of use provide improved efficiency and capacity in removing contaminants,
particularly odor-causing contaminants, from gas streams.
Accordingly, it is an object of the present invention to provide a high capacity
solid filtration media that efficiently removes undesirable compounds from an air
stream to reduce odors, minimize the corrosion of metals or electronics, and to
provide a nontoxic or nonirritating breathing environment for humans and animals.
It is another object of the present invention to provide a high capacity solid
filtration media that is long-lasting and requires minimal maintenance or replacement.
It is yet another object of the present invention to provide a solid filtration
media having a high ignition temperature, and therefore, limited flammability.
It is also an object of the present invention to provide an improved solid
filtration media that is inexpensive to manufacture and use.
composition typically also contains at least approximately 5% water by weight of
media composition. Preferably, the permanganate is a highly water soluble
permanganate salt such as sodium permanganate or lithium permanganate. The
porous substrate is typically selected from, but not limited to, activated alumina, silica
gel, a zeolite, adsorbent clay, kaolin, activated bauxite, or combinations thereof, the
preferred porous substrate being alumina or an alumina-zeolite mix.
Preferred solid filtration media contain from approximately 8 to approximately
25% permanganate, between approximately 5 and 25% water, and a porous substrate.
More preferred solid filtration media contain from approximately 15 to approximately
20% permanganate, between approximately 5 and 25% water, and a porous substrate.
Most preferably, the solid filtration media contain from approximately 18 to
approximately 19% permanganate, between approximately 5 and 25% water, and a
porous substrate. All of the above percentages are by weight of the entire composition
and, as described above, the permanganate has a higher solubility in water than that of
potassium permanganate.
In another embodiment, the media further contain a gas-evolving material,
such as a carbonate compound, a bicarbonate compound, or a combination thereof,
that function by producing a gas (typically CO2) upon heating. For example, when
the composition further contains sodium bicarbonate, the sodium bicarbonate is
present between approximately 5 to 25%, and preferably is between about 15 to 20%
by weight of the entire composition.
The high capacity solid filtration media composition described above are
produced by mixing water, a permanganate, and a substrate, and then forming the
mixture into at least one cohesive porous unit. The unit is then cured at a temperature
of from about 100°F to about 200°F, until the concentration of water is at least about
5% by weight of the composition, and the concentration of the permanganate is at
least about 8% by weight of the composition.
In accordance with a preferred method of making the solid filtration media, an
aqueous solution containing the permanganate is sprayed onto the porous substrate. In
an alternative aspect, water is combined with a dry mixture containing the
It is another object of the present invention to provide a solid filtration media
having such a high capacity for removing undesirable compounds that less media
needs to be utilized, therefore allowing the use of smaller air filtration units.
It is yet another object of the present invention to provide a simple,
inexpensive method of making an improved solid filtration media having a high
efficiency and a high total capacity for the removal of an undesirable compound.
It is a further object to provide a rapid, efficient and inexpensive method of
treating a contaminated air or gas stream with a solid filtration media.
These and other objects, features and advantages of the present invention will
become apparent after a review of the following detailed description of the disclosed
embodiments and the appended claims.
DETAILED DESCRIPTION
High capacity solid filtration media, methods of preparing the same, and
methods of treating a fluid stream with the solid filtration media are provided. The
solid filtration media can be used to remove or reduce undesirable compounds, or
contaminants, from a gaseous fluid stream. The solid filtration media contain
permanganate and a porous substrate. Typically, the media also contain water. A gas-
evolving material such as sodium bicarbonate may also be included. In some
embodiments, at least one zeolite is optionally included in the media. The media
contain significantly higher levels of permanganate than previously believed to be
possible.
Generally described, the filtration media contain a substrate impregnated with
high levels of permanganate. The permanganate is a highly water soluble
permanganate having a solubility in water greater than that of potassium
permanganate. The filtration media include at least about 8% permanganate by weight
of the composition. The permanganate is preferably a permanganate salt such as, but
not limited to, sodium permanganate ("NaMnO4"), magnesium permanganate
("Mg(MnO4)2"), calcium permanganate ("Ca(MnO4)2"), barium permanganate
("Ba(MnO4)2"), and lithium permanganate ("LiMnO4"). More preferably, the
permanganate salt is sodium permanganate (commercially available from chemical
suppliers such as Cams Chemical Co., Peru, IL) or lithium permanganate. Most
preferably, the permanganate is sodium permanganate due to its inexpensive
commercial availability. The concentration of the permanganate in the media is
typically from about 8 to about 25%, more preferably from approximately 15 to
approximately 20%, and most preferably from approximately 18 to approximately
19%, by weight of the composition.
The porous substrate may be selected from the group consisting of, but not
limited to, activated alumina (Al2O3) (UOP Chemical, Baton Rouge, Louisiana), silica
gels (J. M. Huber, Chemical Division, Havre De Grace, Maryland), zeolites (Steel
Head Specialty Minerals, Spokane, Washington), kaolin (Englehard Corp., Edison,
New Jersey), adsorbent clays (Englehard Corp., Edison, New Jersey), and activated
bauxite. A preferred porous substrate is alumina. Preferably, the concentration of
substrate in the filtration media is from about 40 to 80%, and most preferably is from
about 60 to 75% in the absence of sodium bicarbonate and from about 40 to 60% if
the media contain sodium bicarbonate.
Another preferred porous substrate is a combination of alumina and a zeolite,
in which up to about 50% by weight of the porous substrate combination is a zeolite.
Though not intending to be bound by this statement, it is believed that zeolites further
control the moisture content of the filtration media by attracting and holding water,
which functions to keep more of the impregnate in solution. This effect, in turn, is
believed to enhance the high capacity and improved efficiency of the filtration media.
As used herein, the term zeolite includes natural silicate zeolites, synthetic materials
and phosphate minerals that have a zeolite-like structure. Examples of zeolites that
can be used in this media include, but are not limited to, amicite (hydrated potassium
sodium aluminum silicate), analcime (hydrated sodium aluminum silicate), pollucite
(hydrated cesium sodium aluminum silicate), boggsite (hydrated calcium sodium
aluminum silicate), chabazite (hydrated calcium aluminum silicate), edingtonite
(hydrated barium calcium aluminum silicate), faujasite (hydrated sodium calcium
magnesium aluminum silicate), ferrierite (hydrated sodium potassium magnesium
calcium aluminum silicate), gobbinsite (hydrated sodium potassium calcium
aluminum silicate), harmotome (hydrated barium potassium aluminum silicate),
phillipsite (hydrated potassium sodium calcium aluminum silicate), clinoptilolite
(hydrated sodium potassium calcium aluminum silicate), mordenite (hydrated sodium
potassium calcium aluminum silicate), mesolite (hydrated sodium calcium aluminum
silicate), natrolite (hydrated sodium aluminum silicate), amicite (hydrated potassium
sodium aluminum silicate), garronite (hydrated calcium aluminum silicate), perlialite
(hydrated potassium sodium calcium strontium aluminum silicate), barrerite (hydrated
sodium potassium calcium aluminum silicate), stilbite (hydrated sodium calcium
aluminum silicate), thomsonite (hydrated sodium calcium aluminum silicate), and the
like. Zeolites have many related phosphate and silicate minerals with cage-like
framework structures or with similar properties as zeolites, which may also be used in
place of, or along with, zeolites. These zeolite-like minerals include minerals such as
kehoeite, pahasapaite, tiptopite, hsianghualite, lovdarite, viseite, partheite, prehnite,
roggianite, apophyllite, gyrolite, maricopaite, okenite, tacharanite, tobermorite, and
the like.
The concentration of water in the filtration media is typically at least
approximately 5 to 25%, preferably from approximately 10 to 25%. One of ordinary
skill in the art will understand that the concentration of free water in the filtration
media may be altered by the conditions present, such as the humidity and the
temperature, during its storage and use.
Preferably, the solid filtration media includes from approximately 8 to 25%
permanganate, from about 5 to 25% water, and from approximately 40 to 80%
substrate, by weight of the composition. More preferably, the media contain from
approximately 15 to 20% permanganate, from approximately 5 to 25% water, and
from approximately 40 to 80% substrate, by weight. Most preferably, the solid
filtration media contain from approximately 18 to 19% permanganate, from
approximately 10 to 25% water, and from approximately 40 to 60% substrate, by
weight. As described above, the permanganate is ideally sodium permanganate due to
its high solubility in water and inexpensive commercial availability.
The gas-evolving material of the filtration media described herein is a material
that produces or releases a gaseous substance upon heating, for example during the
curing step of forming the filtration media. The bubbles formed in this heating
process are instrumental in enhancing and controlling the pore structure of the
filtration media. The gas-evolving material is usually selected from a carbonate
compound, a bicarbonate compound, or a combination thereof, that functions by
producing carbon dioxide gas upon heating. A preferred gas-evolving material is
sodium bicarbonate, because of its smooth release of carbon dioxide, and its relatively
low cost. However, other bicarbonates and carbonates can be used in this media, the
selection of which is understood by one of ordinary skill in the art. The number and
size of the pores produced from heating the gas-evolving material is related to the
concentration of the gas-evolving material in the solid filtration media, the
temperature of curing, and the time of curing. Thus, increasing the concentration of
sodium bicarbonate in the composition increases the pore size and number, helps
reduce and prevent clogging of the pore structure, enhances the retention of water,
and sustains the concentration of the permanganate in the filtration media.
In a preferred embodiment, the filtration media composition includes a
permanganate, water, a substrate and sodium bicarbonate ("NaHCO3") (Rhone-
Poulenc, Chicago Heights, IL), wherein the concentration of sodium bicarbonate is
from approximately 5 to 25%, and preferably from 15 to 20%, by weight. In the
embodiments where the filtration media contain sodium bicarbonate, the preferred
concentration of alumina is from approximately 40 to 60%.
It is to be understood that, when referring to the relative weight of
components, the water referred to in the present specification, examples, and tables is
defined as the free water, and does not include the bound water in the substrate. Free
water is driven off by an oven at approximately 200°F, but if left in the substrate it is
available for the oxidation reaction. In contrast, bound water is not driven out or
evaporated except by a kiln at about 1800 to 2000°F, and the bound water functions
by holding the substrate together. Bound water is not available for reaction with the
undesirable contaminants.
It is also to be understood that the term permanganate as used quantitatively in
the present specification, examples, and tables represents the permanganate salt, not
the permanganate ion, MnO4". Therefore, the percent ranges of permanganates in
compositions in the present specification denote the percent of the permanganate salt
in the composition, not the percent of the permanganate ion in the composition.
Terms such as "filtration media", "adsorbent composition," "chemisorbent
composition," and "impregnated substrate" are all interchangeable, and denote a
substance that is capable of reducing or eliminating the presence of unwanted
contaminants in fluid streams by the contact of such a substance with the fluid stream.
It is to be understood that the term "fluid" is defined as a liquid or gas capable of
flowing, or moving in a particular direction, and includes gaseous, aqueous, organic
containing, and inorganic containing fluids.
Solid Filtration Media Preparation Methods
Also provided is a method of preparing high capacity solid filtration media.
The method includes mixing water, a permanganate, an optional gas-evolving
material, and a porous substrate, and then forming the mixture into at least one
cohesive porous unit. The unit is then typically cured at a temperature of from about
100°F to about 200°F, until the concentration of water is at least about 5% by weight
of the composition, and the concentration of the permanganate is at least about 8% by
weight of the composition. The size and shape of the cohesive porous unit is not
critical. Any size and shape of a porous unit known in the art to reduce or eliminate
undesirable contaminants from fluid streams when in contact with the unit may be
used. Preferably, the porous unit is a nominal 1/8" diameter round pellet.
The method provided herein preferably includes forming an aqueous solution
containing the permanganate and optional gas-evolving material and then mixing the
aqueous permanganate solution with the porous substrate. To dissolve and maintain
the permanganate in solution, the aqueous solution should be heated to approximately
160° to 200°F, and preferably to approximately 180° to 190°F.
In another embodiment, the method includes forming a dry mixture containing
the permanganate and the porous substrate, and then adding water to the dry mixture.
In yet another embodiment, the method includes forming a dry mixture containing the
permanganate, the optional gas-evolving material, and the porous substrate; forming a
separate aqueous solution containing the permanganate and the optional gas-evolving
material, and then mixing the aqueous solution with the dry mixture. Optionally, the
gas-evolving material such as sodium bicarbonate may be added either to the dry
mixture, to the water, or to both in the above methods of preparing the filtration
media.
Preferably, the unit formed is cured until the concentration of water is from
about 5 to about 25%, most preferably from about 10 to about 25% by weight of the
composition; the concentration of the permanganate is at least about 8 to about 25%
by weight of the composition, more preferably from about 15 to about 20%, and most
preferably from about 18 to about 19%; and the concentration of the gas-evolving
material is from about 5 to about 25% by weight of the composition, most preferably
from about 15 to 20% by weight of the composition, after curing. The presence of a
gas-evolving material such as sodium bicarbonate allows for a lower curing
temperature, such as about 130° to 140°F, in contrast to the conventional curing
temperature of about 200°F.
The impregnation treatment of the activated starting material in accordance
with the present method has not been found to be critical with respect to the particular
sequence in which the dry mix is impregnated with moisture and impregnates. The
above combinations may be mixed in any manner which effectively produces the
desired filtration media. Impregnation may be carried out simply by immersing and
soaking the solid combination in a volume of impregnate solution. Also, the
impregnate solution may be passed through the combination rather than being used as
a static immersion treatment. However, it has been found that a preferred method of
impregnation is spray addition in which an impregnate solution is sprayed onto a dry
combination being tumbled in a mixer. This method of impregnation has been
described in U.S. Pat. No. 3,226,332, which is herein incorporated by reference in its
entirety. Other methods of impregnating the combinations will suggest themselves as
equally appropriate, and these are included within the scope of the present method.
In one embodiment utilizing the above spray addition method, the aqueous
impregnate solution of permanganate is sprayed onto a dry combination of gas-
evolving material, such as sodium bicarbonate, and a porous substrate, such as
activated alumina. For example, the dry combination preferably contains between
approximately 80 to 85% activated alumina and between approximately 15 to 20% of
sodium bicarbonate.
The concentration of the permanganate may vary in the solution to be sprayed
onto the dry combination. For example, to produce a solid filtration medium
containing approximately 20% permanganate, an aqueous solution containing
approximately 40% of permanganate, at between approximately 160°F to 200°F, and
preferably at about 180°F to 190°F should be sprayed on the dry combination of gas-
evolving material and porous substrate being tumbled in a mixer. Also, to produce a
solid filtration medium containing approximately 8-9% permanganate, a solution of
approximately 18% permanganate at between approximately 160°F to 200°F, and
preferably at about 180°F to 190°F should be sprayed on the dry combination of gas-
evolving material and porous substrate being tumbled in a mixer. Any concentration
of permanganate in the aqueous solution which is effective to yield the composition
described herein may be used. Further, where the permanganate is either in the dry
feed mixture or in both the aqueous solution and the dry feed mixture, any
concentration of permanganate in the dry mixture and/or the aqueous solution which
is effective to produce the composition described herein may be used. For example,
the media may be used to fill perforated modules to be inserted into air ducts in a
manner known in the art.
Contaminant Removal Methods
Also provided is a method of treating a contaminated fluid stream using the
high capacity solid filtration media described herein or produced by the process
described above. This method involves contacting the contaminated fluid stream with
the solid filtration composition provided herein. Typically, the undesired
contaminants will be removed from air, especially from air admixed with effluent gas
streams resulting from municipal waste treatment facilities, paper mills,
petrochemical refining plants, morgues, hospitals, anatomy laboratories, and hotel
facilities, and so forth. Methods of treating gaseous or other fluid streams are well
known in the art. As the method of treating fluid streams is not critical to the present
invention, any method known in the art of treating fluid streams with the media
described herein may be used.
The composition described herein is useful for removing undesired
contaminants from gaseous streams. Undesirable airborne compounds to be removed
using the high capacity filtration media include, but are not limited to, sulfur
compounds (such as hydrogen sulfide and dimethyl sulfide), ammonia, chlorine,
formaldehyde, urea, carbon monoxide, oxides of nitrogen, mercaptans (such as
methyl mercaptan), amines, isopropyl alcohol and ethylene. Typically, contaminants
to be removed by employing the media described herein include, but are not limited
to, ethylene, formaldehyde and methyl mercaptan The concentrations of undesirable
contaminants in the gaseous streams is not considered critical to the process of
contaminant removal, nor is the physical and chemical makeup of the gas stream
considered critical. Even concentrations of these undesirable compounds in gas
streams resulting in levels lower than one ppb of the compounds passing through a
solid filtration media bed per minute may be removed.
However, it has been found that flow rates of the gas stream being contacted
with the bed of filtration media affect the breakthrough capacities of the media. The
preferred flow rate is between 10 and 750 ft/min, and most preferably is between 60
and 100 ft/min, flowing perpendicularly to the face of the bed.
While not intending to be bound by the following statement, it is believed that
it may be necessary that certain oxidizing conditions prevail while using the solid
filtration media described herein. The extent of oxidation may affect the degree of
purification achieved. Preferably, oxygen is present in the gas stream being treated, at
least in small amounts. This oxygen content is readily found in the gas stream, if air
constitutes a sufficient portion of the gas stream being treated. If oxygen is totally
absent or present in insufficient amounts, oxygen may be independently introduced
into the gas stream being treated. A number of factors affect the amount of oxygen,
which may be required for maximum removal of the contaminants in a gas stream in
accordance with the present method, including the concentration and absolute amount
of compounds being removed from the gas stream being treated.
With respect to the amount of compound removed, it is believed that the
following factors affect the process: the basic degree of attraction of the activated
substrate for the compound; the pore structure and pore size distribution; the size of
the substrate; the specific surface area of the substrate as affected by the number and
size of pores; the surface characteristics of the substrate; the amount of permanganate
present; the amount of gas-evolving material present in the composition, which
affects the number, size, and perhaps structure of pores; and the amount of water
present.
The filtration media provided herein is appropriately used alone in filter beds
for the removal of undesirable compounds. It is also appropriate, however, to use the
composition in conjunction with filter beds containing other filtration media, and also
in conjunction with mechanical or electrostatic filters. Any such additional filters
may be placed either upstream (before the media described herein with respect to the
effluent gas being treated) or downstream.
The above invention significantly increases the efficiency and capacity of
impregnated porous substrates (filtration media) to remove certain undesired
compounds from gaseous streams over the capacity of impregnated substrates
currently available. Therefore, the lifetime of a specific quantity of the high capacity
filtration media will be much longer than the same quantity of the currently available
filtration media.
The extension of the lifetime of the filtration products will significantly reduce
the purchasing, servicing, and installation costs of consumers and businesses. Also,
the enhanced efficiency of the media allows for a new line of products, which are
compact versions of currently available units, but have the same performance as the
larger, currently available units. The capability of creating significantly smaller
filtration units is useful for providing efficacious air filtration in space-limited
quarters, which previously could not utilize the larger, currently available units.
Also, the filtration media described herein is less expensive than other
filtration media having a roughly equivalent capacity. For example, the media of the
present invention has a capacity equivalent or superior to the contaminant capacity of
activated carbon adsorbents, particularly in respect to ethylene and formaldehyde
contaminants. However, the media provided herein is considerably less expensive
than activated carbon adsorbents.
Further, the filtration media provided herein is safe as it is not flammable, in
contrast to carbon-containing filtration products. This characteristic of the presently
provided filtration media is significant to industries that manufacture or process
flammable, fume producing materials, such as the petroleum industry for example.
In the high capacity filtration media described herein, the use of a highly water
soluble permanganate, having a water solubility higher than that of potassium
permanganate, allows for an increase in the concentration of permanganate in the
media. This increased concentration of permanganate greatly increases the removal
capacity of the media for contaminants. When performing accelerated capacity tests
as described in the examples below, the filtration media is examined at 100%
efficiency until the efficiency drops to a pre-determined level, in this case 99.5%
efficiency. Once this breakthrough is achieved the test is complete, and removal
capacity can then be calculated. The capacity level is inherently linked to efficiency,
because it is determined in association with the time taken for the efficiency to drop
to 99.5%. Currently available potassium permanganate impregnated alumina media
has a capacity of approximately 3% for the removal of ethylene. In contrast, the high
capacity filtration media described herein containing approximately 60% activated
alumina, approximately 15-20% water, and 19-20% sodium permanganate, exhibited
an ethylene capacity of approximately 9%. Capacity tests were performed by
challenging a known quantity of the selected solid filtration media with 1.0% (by
volume) ethylene gas at a constant flow rate and monitoring the concentration of
ethylene in the gas stream exiting the solid filtration media. The accelerated removal
capacity test is fully described in U.S. Patent No. 6,004,522, which is herein
incorporated by reference in its entirety.
The high capacity of the solid filtration media described herein is not limited
to the removal of ethylene from a gaseous stream. Indeed, high capacity is similarly
achieved for other gaseous contaminant such as hydrogen sulfide, formaldehyde and
methyl mercaptan. The results of these investigations are presented in the Examples,
below.
Although the precise mechanisms by which the high capacity media operates
are not understood or fully appreciated, and its scope is not bound by the following
theory, it is believed that the oxidation reactions between the permanganate and the
undesirable contaminants occur primarily near the surface of the filtration media,
rather than deep within its pores. Therefore the media most likely perform at optimal
levels when the oxidative capabilities of the surface are continually regenerated. It is
believed that the oxidative capability of the surface of the media is regenerated by the
flow or migration of permanganate from the center of the media to the surface of the
media while the products of the oxidation reactions flow or migrate from the surface
of the media to the center of the media. It is also believed that the higher the
concentration of permanganate at the surface of the media, the higher the capacity and
efficiency of the media.
Furthermore, the fluidity of the permanganate solution directly affects the flow
and thus the quantity of the permanganate reaching the surface of the media.
Therefore, the media work well when an elevated concentration of free water is
maintained in the media so that the permanganate solution maintains a high level of
fluidity and readily flows to the surface of the media thereby maximizing the
efficiency and capacity of the media. A liquid path thus should be established
between the interior of the pores and the surface of the media. In this regard, the
improved pore structure provided by the addition of a gas-evolving material to the
filtration media is believed to enhance the ready flow of permanganate solution. This
is contrary to conventional theories, which teach a need for penetration of the gaseous
contaminants into the pores of the substrate.
This theory, presented above, explains why the capacity and efficiency of the
traditional filtration media could not surpass the capacity and efficiency obtained at
the potassium permanganate concentrations of 4-5%. As stated above, previously,
various attempts were made to impregnate the media with higher quantities of
potassium permanganate, however, the majority of the free water has always been
removed from these media. The efficiency and capacity of these highly impregnated
potassium permanganate media remained constant or decreased relative to the
capacity achieved by media impregnated with 4-5% permanganate. There are three
reasons for the failure of the highly impregnated media currently available to obtain
higher results. First, the high concentration of permanganate and the low
concentration of water causes the permanganate to crystallize and clog the pores of
the substrate thereby blocking the flow of permanganate to the surface of the media.
Second, the crystallized permanganate remains in the center of the media and
therefore cannot move to the surface of the media to oxidize contaminants. Third, it is
difficult for any permanganate that may be in solution to move to the surface of the
media as the permanganate solution is very concentrated and has a low level of
fluidity. It is for these reasons that maintaining an elevated level of water in the media
is believed to be useful for improved filtration media, and is included in the present
invention. It is also believed that the unprecedented improvement in solid filtration
media of this invention is due to recent advances in the preparation and supply of
commercially available permanganates. Historically these permanganates are supplied
either as granular crystals or relatively low aqueous concentrations. Potassium
permanganate is known to crystallize in high concentration, as frequently
demonstrated in the literature. Concentrated aqueous potassium permanganate (20%)
can also precipitate during curing, and ultimately clog the pores of filtration media.
However, a permanganate having a water solubility greater than that of potassium
permanganate, such as sodium permanganate, is miscible in water in all proportions
(by comparison, potassium permanganate solubility is approximately 6.5g/100ml by
weight, at 20°C). Due in part to the important difference in solubility, it is now
possible to incorporate substantially higher concentrations (>20%) of permanganates,
such as sodium permanganate, than previously obtained, ultimately yielding an
increased removal capacity of contaminates from gaseous streams. Furthermore, the
significant increase in removal capacity of ethylene contaminants is due in part to the
increased concentration of permanganate, but also due to the formation of relatively
small non-volatile waste products (CO2 and H2O) which are released from the solid
filtration media, effectively providing additional active surface area for multiple
reactions with other gaseous contaminants.
The following examples will serve better to illustrate the high capacity of the
solid filtration media described herein for the removal of contaminants in gas streams.
It should be noted that the continuous flow systems described in several of the
following examples all were operated at a relative humidity of 40-50%.
EXAMPLE 1
Preparation of Filtration Media Containing 13% Sodium Permanganate
A sodium permanganate impregnated alumina composition is prepared as
follows.
A dried feed mix is prepared by combining, by weight, 80-85% alumina, and
15-20% sodium bicarbonate. The dry feed mixture is sprayed with a heated aqueous
sodium permanganate solution at 180 to 190°F while being tumbled in a tumble mill.
The resulting pellets are dried at 130 to 140°F until the pellets contain about 20 to
25%o free water.
To prepare solid filtration media containing approximately 13% sodium
permanganate by dry weight, the aqueous sodium permanganate solution preferably
contains approximately 26% sodium permanganate by weight. It is to be understood
that the aqueous sodium permanganate solution is sprayed onto the dry feed while the
dry mix is rolled in the pelletizing disk as described in U.S. Patent No. 3,226,332,
incorporated herein by reference.
EXAMPLE 2
Preparation of Filtration Media Containing; 4-5% Potassium Permanganate
A 4-5% potassium permanganate impregnated alumina composition was
prepared as follows.
A dry feed mix, consisting of 100% alumina, was sprayed with a heated
aqueous potassium permanganate solution at 180 to 190°F while the dried feed was
tumbled in a tumble mill. The resulting pellets were then dried at 130 to 140°F until
the pellets contained about 20 to 25% free water.
To prepare solid filtration media containing approximately 4-5% potassium
permanganate by dry weight, the aqueous potassium permanganate solution
preferably contained approximately 10% potassium permanganate by weight. It is to
be understood that the aqueous potassium permanganate solution was sprayed onto
the dry feed while the dry mix was rolled in the pelletizing disk as described in U.S.
Patent No. 3,226,332.
EXAMPLE 3
Preparation of Filtration Media Containing 19-20% Sodium Permanganate
A 19-20% sodium permanganate impregnated alumina composition was
prepared as follows.
A dried feed mix, consisting of 100% alumina, was sprayed with a heated
aqueous sodium permanganate solution at 180 to 190°F while the dried feed was
being tumbled in a tumble mill. The resulting pellets were then dried at 130 to 140°F
in air until the pellets contained about 20 to 25% free water.
To prepare a solid filtration media containing approximately 19-20% sodium
permanganate, by dry weight, the aqueous solution preferably contained
approximately 40% sodium permanganate, by weight. It is to be understood that the
aqueous potassium permanganate solution was sprayed on to the dry feed while the
dry feed was rolled in the pelletizing disk as described in U.S. Patent No. 3,226,332.
EXAMPLE 4
Preparation of Additional Permanganate-Impregnated Substrates
Using the methods described in Examples 2 and 3, above, the following
compositions, by dry weight, were also prepared.

The dry feed mix, consisting of 100% alumina, was mixed in a tumbling mill
and sprayed with the appropriate amount of aqueous potassium permanganate or
aqueous sodium permanganate solution, while tumbling, in the manner described in
U.S. Patent No. 3,226,332. Curing was carried out as in Examples 2 or 3 to provide
the cured pellets as a strong, non-dusting filter media suitable for placement in filter
beds.
EXAMPLE 5
Standard Accelerated Test Method for Capacity Determination of Gas-Phase Air
Filtration Media.
The following accelerated test method is useful for determining the capacity of
removal of various gas-phase air filtration media when subjected to a flowing gas
stream containing high levels of contaminant(s). Low-level challenge testing of gas-
phase air filtration media, whether full-scale or small-scale, usually takes long periods
of time to obtain the desired results. The following method provides an accelerated
test for determining the removal capacities of various media by exposing them to high
levels of contaminants.
The method is briefly summarized as follows: a known volume of media is
placed in an adsorption tube and exposed to a known concentration (usually 1% by
volume) of contaminant gas(es) in a tempered, humidified, clean air system. The gas
stream is calibrated to deliver a total flow rate of 1450±20 ml/min. The removal
capacity is calculated as the amount (in grams) of contaminant removed from the air
stream per volume (cubic centimeters) of media at a 50 parts per million ("ppm")
breakthrough.
More specifically, the air utilized must be tempered, humidified, clean, oil-
free, and compressed. Accordingly, the air must be passed through a bed of activated
carbon followed by a filter bed containing sodium permanganate impregnated
alumina pellets. Each filter bed should contain at least 300 ml (18.3 cu. in.) of media
for each liter per minute (0.035 cfm) of air flow. The media in each filter bed should
be changed before each test.
Media samples are preferably obtained from unopened original manufacturer's
shipping or storage containers chosen at random whenever possible. The entire
container, whenever possible or practical, should be sampled by taking small amounts
of media from throughout the container and combining them into one larger sample.
The sample should be thoroughly mixed before being analyzed. Guidance on
sampling may be obtained from ASTM Standard E300, entitled Recommended
Practice for Sampling Industrial Chemicals. If a test is to be run comparing media of
the same size or different sizes, the sample collected may be screened through the
appropriate sieves to sort the media by size.
Using an appropriate sampling method, obtain a representative sample of
media (approximately 400 grams should be sufficient) and determine its apparent
density as per ASTM 2854, or an equivalent method. Obtain an adsorption tube which
is a cylindrical tube where glass wool and/or beads are optionally placed below the
media, and the media and optional glass wool or beads are supported by stainless steel
mesh, a perforated slotted glass disc, or a perforated slotted ceramic disc positioned
below the media and glass wool or beads. After the adsorption tube having the glass
wool or glass beads has been calibrated for the volume of a known depth of media,
weigh the adsorption tube to the nearest 1.0 mg. Fill the adsorption tube to the desired
depth via alternately filling and gently tamping the tube to eliminate any dead space
until the desired depth is reached. Weigh the filled adsorption tube to the nearest 1.0
mg.
The filled media tube is arranged such that a mixture of air and contaminated
gas enters the bottom of the tube, flows through the glass wool or beads, flows
through the filtration media, and is then analyzed by a gas analyzer. Leaks in the gas
system should be checked for and eliminated before beginning the analysis of the
sample. Rotameters, analyzers, recorders, etc. should be calibrated over appropriate
ranges according to the manufacturer's instructions or other standard methods such as
ASTM Standard D3195, before any media is introduced into the system. Also, air and
gas flow requirements should be determined and checked against supply capabilities
to assure proper air and gas flows to the system.
Once the adsorption tube is in position, start the flow of the mixture of
contaminated gas and air and record the time, or time the test using a stop watch.
Continue the flow of the mixture of gas and air until a breakthrough of 50 ppm is
observed or indicated by the gas analyzer. Record the time at breakthrough. It is
preferable to use a gas analyzer capable of variable scale readouts to 50 ppm (±5
ppm), having specific or multiple gas capabilities.
The data obtained from the above analysis will yield the gas capacity of the
media tested using the following equation:
GAS CAPACITY (GM/CC) = (K x 10-5)(C)(F)(tb) / V
where:
K=1.52 for H2S, 2.86 for SO2, 3.17 for Cl2, 2.15 for CH3SH, 0.76 for NH3,
2.05 for NO2, 1.16 for C2H4, 1.34 for OCH2, and 1.39 for NO.
C=Concentration of challenge gas in air stream, Volume %.
F=Total stream flow rate, cc/min.
tb =Time to 50 ppm breakthrough, minutes.
V=Volume of the adsorption tube media column, cc.
EXAMPLE 6
Capacity of Permanganate Impregnated Alumina Pellets in the presence of H2S.
The results of tests comparing the capacities of various solid filtration media
are summarized in Table II below. The capacity tests were performed by challenging
a known quantity of the selected solid filtration media with 1.0% hydrogen sulfide gas
at a constant flow rate and monitoring the concentration of hydrogen sulfide in the gas
stream exiting the solid filtration media as described in Example 5.

EXAMPLE 7
Capacity of Permanganate Impregnated Alumina Pellets in the presence of Ethylene.
The results of tests comparing the capacities of various solid filtration media
are summarized in Table III below. The capacity tests were performed by challenging
a known quantity of the selected solid filtration media with 1.0% ethylene gas at a
constant flow rate and monitoring the concentration of ethylene in the gas stream
exiting the solid filtration media as described in Example 5.

EXAMPLE 8
Capacity of Permanganate Impregnated Alumina Pellets in the Presence of
Formaldehyde.
The results of tests comparing the capacities of various solid filtration media
are summarized in Table IV below. The capacity tests were performed by challenging
a known quantity of the selected solid filtration media with 1.0% formaldehyde gas at
a constant flow rate and monitoring the concentration of formaldehyde in the gas
stream exiting the solid filtration media as described in Example 5.

EXAMPLE 9
Capacity of Permanganate Impregnated Alumina Pellets in the Presence of Methyl
Mercaptan.
The results of tests comparing the capacity of solid filtration media of the
present invention are summarized in Table V below. The capacity tests were
performed by challenging a known quantity of the selected solid filtration media with
1.0% methyl mercaptan gas at a constant flow rate and monitoring the concentration
of methyl mercaptan in the gas stream exiting the solid filtration media as described
in Example 5.

It should be understood, of course, that the foregoing relates only to certain
embodiments of the present invention and that numerous modifications or alterations
may be made therein without departing from the spirit and the scope of the invention.
All of the publications or patents mentioned herein are hereby incorporated by
reference in their entireties.
WE CLAIM
1. A high-capacity solid filtration composition comprising a permanganate
salt having a solubility in water greater than that of potassium
permanganate, wherein the concentration of permanganate salt in the
composition is 13% to by weight.
2. The composition as claimed in claim 1, wherein the permanganate slat is
selected from the group consisting of sodium permanganate, magnesium
permanganate, calcium permanganate, barium permanganate, lithium
permanganate, or a combination thereof.
3. The composition as claimed in claim 1, wherein the composition comprises
at least 15 to 20% permanganate salt by weight.
4. The composition as claimed in claim 1, wherein the composition comprises
at least 18 to about 19% permanganate salt by weight.
5. The composition as claimed in claim 1, wherein the composition comprises
at least 5% and 25% water by weight.
6. The composition as claimed in claim 1, wherein the permanganate salt
comprises sodium permanganate.
7. The composition as claimed in claim 1, comprising a gas evolving material
selected from a carbonate compound, a bicarbonate compound, or a
combination thereof.


8. The composition as claimed in claim 1, wherein the permanganate salt is
impregnated with a porous substrate, and wherein the porous substrate
comprises activated alumina, a silica gel, a zeolite, a zeolite-like mineral,
kaolin, an adsorbent clay, activated bauxite, or a combination thereof, and
wherein the porous substrate is between 40 and 80% weight
of the composition.
9. The composition as claimed in claim 8, wherein the zeolite or zeolite-like
mineral is selected from amicite, analcime, pollucite, boggsite, chabazite,
edingtonite, faujasite, ferrierite, gobbinsite, harmotome, phillipsite,
clinoptilolite, mordenite, mesolite, natrolite, garronite, perlialite, barrerite,
stilbite, thomsonite, kehoeite, pahasapaite, tiptopite, hsianghualite,
lovdarite, viseite, partheite, prehnite, roggianite, apophyllite, gyrolite,
maricopaite, okenite, tacharanite, tobermorite, or a combination thereof.
10.The composition as claimed in claim 7, wherein the gas-evolving material
comprises sodium bicarbonate and the porous substrate comprises
activated alumina or a combination of activated alimina and at one zeolite
or zeolite-like mineral.
11.The composition as claimed in claim 10, wherein the concentration of
sodium bicarbonate is between 5 and 25% by weight of the
composition.

12. A method of treating a contaminated fluid stream comprising contacting
the contaminated fluid stream with a high-capacity solid filtration
composition as claimed in claims 1 to 11, wherein the solid filtration
composition comprises a permanganate salt having a solubility in water
greater than that of potassium permanganate wherein the concentration
of permanganate salt in the composition is 13% to 25% by
weight.
13.The method as claimed in claim 12, wherein the concentration of
permanganate is between 15 and 20% by weight of the
composition.
14.The method as claimed in claim 12, wherein the concentration of
permanganate is between 18 and 19% by weight of the
composition.
15.The method as claimed in claim 12, wherein the composition comprises a
gas-evolving material having a concentration between 5 and
25% by weight of the composition.
16.The method as claimed in claim 12, wherein the contaminated fluid
stream contains hydrogen sulfide and the removal capacity of the solid
filtration unit is at least 16%.
17.The method as claimed in claim 12, wherein the contaminated fluid
stream contains ethylene and the removal capacity of the solid filtration
unit is at least 4%.

18.The method as claimed in claim 12, wherein the contaminated fluid
stream contains formaldehyde and the removal capacity of the solid
filtration unit is at least 4%.
19.The method as claimed in claim 12, wherein the contaminared fluid
stream contains methyl mercaptan and the removal capacity of the solid
filtration unit is at least 6%.


20. A method of preparing a high capacity solid filtration composition
comprising :
a. mixing a permanganate salt having a solubility in water greater
than that of potassium permanganate;
b. spraying the mixture with water;
c. forming the mixture into at least one cohesive porous unit; and
d. curing the unit at a temperature of form 100°F to about-
200°F until the concentration of water is at least 5% by
weight of composition, and the concentration of permanganate salt
is 13% to 25% by weight.

21.The method as claimed in claim 20, wherein the unit is cured until the
concentration of permanganate is between 13 and 25% by
weight of the composition.

22.The method as claimed in claim 20, wherein the unit is cured until the
concentration of permanganate is between 15 and 25% by
weight of the composition.
23.The method as claimed in claim 20, wherein the unit is cured until the
concentration of permanganate is between 18 and19% by
weight of the composition.
24.The method as claimed in claim 20, wherein the unit is cured until th3
water concentration is between and 25%.
25.The method as claimed in claim 20, wherein the porous substrate
comprises activated alumina, a silica gel, a zeolite, a zeolite-like mineral,
kaolin, an adsorbent clay, activated bauxite, or a combination thereof.
26.The method as claimed in claim 20, comprising mixing the permanganate
and porous substrate with a gas-evolving material, wherein the gas-
evolving material is selected from a carbonate compound, a bicarbonate
compound, or a combination thereof.
27.The method as claimed in claim 20, comprising a gas-evolving material,
wherein the concentration of gas-evolving material is between 5
and 25% by weight of the composition.

28.The method as claimed in claim 20, wherein the gas-evolving material is
sodium bicarbonate and the porous substrate is activated alumina or a
combination of activated alumina and at least one zeolite or zeolite-like
mineral.
29.The method as claimed in claim 28, wherein the zeolite-like minral is
selected from amicite, analcime, pollucite, boggsite, chabazite,
edingtonite, faujasite, ferrierite, gobbinsite, harmotome, phillipsite,
clinoptilolite, mordenite, mesolite, natrolite, garronite, perlialite, barrerite,
stilbite, thomsonite, kehoeite, pahasapaite, tiptopite, hsianghualite,
lovdarite, viseite, partheite, prehnite, roggianite, apophyllite, gyrolite,
maricopaite, okenite, tacharanite, tobermorite, or a combination thereof.
30.The method as claimed in claim 20, wherein the concentration of the
porous substrate comprises between 40% and 60%.

31.The composition as claimed in claim 1, wherein the solubinity of the
permanganate salt is greater than 6.5g/100 ml in weight, at 20°C.
Dated this 23rd day of June, 2005

This invention relates to a high-capacity solid filtration composition comprising a
permanganate salt having a solubility in water greater than that of potassium
permanganate, wherein the concentration of permanganate salt in the
composition is 13% to 25% by weight.

Documents:

1215-KOLNP-2005-FORM 27-1.1.pdf

1215-KOLNP-2005-FORM 27.pdf

1215-KOLNP-2005-FORM-27.pdf

1215-kolnp-2005-granted-abstract.pdf

1215-kolnp-2005-granted-claims.pdf

1215-kolnp-2005-granted-correspondence.pdf

1215-kolnp-2005-granted-description (complete).pdf

1215-kolnp-2005-granted-examination report.pdf

1215-kolnp-2005-granted-form 1.pdf

1215-kolnp-2005-granted-form 18.pdf

1215-kolnp-2005-granted-form 2.pdf

1215-kolnp-2005-granted-form 26.pdf

1215-kolnp-2005-granted-form 3.pdf

1215-kolnp-2005-granted-form 5.pdf

1215-kolnp-2005-granted-reply to examination report.pdf

1215-kolnp-2005-granted-specification.pdf


Patent Number 230141
Indian Patent Application Number 1215/KOLNP/2005
PG Journal Number 09/2009
Publication Date 27-Feb-2009
Grant Date 25-Feb-2009
Date of Filing 23-Jun-2005
Name of Patentee PURAFIL, INC.
Applicant Address 2654 WEAVER WAY, DORAVILLE, GA
Inventors:
# Inventor's Name Inventor's Address
1 ENGLAND, WILLIAM, G. 2654 WEAVER WAY, DORAVILLE, GA 30340
PCT International Classification Number B01D 39/00, 39/06
PCT International Application Number PCT/US2003/037894
PCT International Filing date 2003-11-25
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/428,958 2002-11-25 U.S.A.
2 65/512,841 2003-10-20 U.S.A.