Liquid purification or separation – Filter – Material
Reexamination Certificate
2002-04-08
2004-07-27
Kim, John (Department: 1723)
Liquid purification or separation
Filter
Material
C210S503000, C210S505000
Reexamination Certificate
active
06767460
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improved filter media containing an ion exchange micronized porous powder polymeric additive, which is associated with the filter media through a water soluble charged liking polymer to improve the efficiency of the filter media.
Further the present invention relates to a filter media having a micronized porous powder polymeric additive having at least 50% of the total number of particles in the additive less than 4 microns. In brief the filter media includes the addition of the micronized ion exchange additive to the filter media to improve the efficiency of the filter media. There are many gases and liquids that contain charged ions such as anions and/or cations. These include liquids such as aqueous and organic based and mixtures, derived from processes and waste streams. Many of these streams contain cations and/or anions which need to be reduced to a certain level and/or removed in order to minimize the concentration of such ions prior to discharge as a waste and/or reuse as a process liquid. In certain instances the ions such as heavy metal ions provide a major environmental concern at both industrial and governmental sites. In addition certain ions have value and can be recovered. For example certain ions such as antimony, iron, nickel, copper, silver, and other metal cations including alkaline earth metal ions need to be removed from the process water for process water recycle and/or water discharge. Further there are anions in liquids which need to be reduced and/or minimized such as borate anions. As is well known the reuse of process liquids, discharge of liquids, and water runoff can present significant environmental concern and contamination of both water sources and soil.
SUMMARY OF THE INVENTION
A new filter media which improves the efficiency for binding certain charged ions to the filter media has been discovered. In brief, the filter media includes the addition of a micronized porous organic polymer powder ion exchange additive having functional groups with a preferential affinity for certain charged ions in streams processed by the filter media.
A new filter media, which improves the efficiency of filter media for ion binding has been discovered. In brief the filter media includes the association of a micronized porous organic polymer ion exchange additive having at least 50% of the total number of particles in the additive less than 4 microns with the filter media to bind certain charged ions in the processed medium. In brief the efficiency of the filter media is improved by providing a significant increase in both the surface area and the number of ion exchange additive particles per unit volume in the filter media. The increase in surface area and number of particles per unit volume provides for improvement in binding efficiency between the additive and the charged ion particularly an improvement in both the capacity and the rate at which the ion is removed from the processed stream.
DETAILED DESCRIPTION OF THE INVENTION
In one broad aspect, the present filter media comprise the addition of a micronized porous organic polymer ion exchange powder additive containing functional groups with a preferential affinity for certain charged ions to the filter media. In a preferred embodiment, the porous organic polymers have a plurality of micro and macropores, i.e. the porosity of the polymer allows the charged ion in the medium to contact both the outer surface of the polymer and the internal surface area created by the porosity of the organic polymer. The functional groups having a preferential affinity for a charged ion including both functional groups on the outer surface and internal surfaces in contact with ions such as in a liquid. The ion exchange additives are typically incorporated into the filter media in an amount sufficient to improve the efficiency of the filter media.
In another broad aspect, the filter media comprise the addition of both the micronized ion exchange additive and a macroporous additive to the filter media.
In another broad aspect, the present filter media comprise the addition of macroporous additive particles to filter media to improve the overall ion distribution to the ion exchange additive. In brief the filter media include the addition of macroporous containing particles having an average particle size distribution greater than that of the ion exchange additive and having a pore size distribution which will allow a plurality of ion exchange additive particles to be associated with at least a part of the internal pore structure of the macroporous additive.
In another broad aspect the porous ion exchange additive can be associated with one or more of the fibers and/or particulate and/or the macroporous particle additive in the filter media through a polymeric charged water soluble linking agent to improve the overall enhanced association and distribution of the ion exchange additive during filter media manufacture and/or use.
A particularly preferred embodiment of the present invention is the use of a charged water soluble linking agent to improve the overall enhanced association of the ion exchange additive with one or more of the components of the filter media. Thus the water soluble charged linking agent can form a bridge and/or link between the micronized ion exchange additive and one or more of the components of the filter media. It has been found that the charged linking agent allows for a more uniform dispersion or distribution of the micronized ion exchange additive throughout the filter media which allows for a more effective use of the micronized particle additive in the filter media particularly from the standpoint of capacity and capture efficiencies for ions to be bound by the ion exchange additive.
The water soluble linking agent typically has a charge opposite that of the charge on one or more of the components of the filter media and the micronized ion exchange additive. For example when the ion exchange additive is a cation exchange additive, i.e. the additive binds cations in for example a liquid such as water, i.e. surface anion charges, it is preferred that a cationic water soluble linking agent, i.e. a positive charge be used to provide for the uniform distribution of the additive in the filter media. Further components of the filter media such as cellulose, glass, and other type fibers can have a negative charge which improves overall distribution and uniformity of the ion exchange additive. Further particulate type material used in filter media such as expanded perlite, diatomaceous earth can also have negative or anion charges which also provide for improved uniformity of the ion exchange additive in the filter media.
In addition to cationic water soluble linking agents, anionic water soluble linking agents can also be used. These agents typically carry a negative charge and will associate with components of the filter media which have a positive charge. As is known by those of skill in the art charges on various fibers and/or particulate components of filter media can be modified to provide a positive charge. Thus the use of an anionic water soluble linking agent which has a negative charge can provide for a uniform distribution of an anionic ion exchange additive, i.e. it binds soluble anions in aqueous liquids and such anionic linking agents can provide for uniform distribution of the ion exchange additive on one or more of the components of a filter media.
As is set forth below, the water soluble charged linking agents preferentially bind with the outer surface functional groups of the micronized ion exchange additive while being of a molecular weight, geometric size which limits and/or minimizes the contact of the linking agent with the internal functionality of the micronized additive. It has been found that the water soluble charged linking polymers provide for an improved uniform distribution of the micronized additive and in addition provides for ease of manufacture of the filter media.
The organic polymers having functional groups wi
Ensci Inc.
Kim John
Uxa Frank J.
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