Process for removal of dissolved components from solution

Details Process for removal of dissolved components from solution Process for removal of dissolved components from solution

2000-10-10

2002-08-13

Hruskoci, Peter A. (Department: 1724)

Liquid purification or separation

Processes

Making an insoluble substance or accreting suspended...

C210S731000, C210S737000, C210S778000, C210S916000, C210S917000, C426S495000

Reexamination Certificate

active

06432315

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for the removal of dissolved components from liquid solutions. More particularly, the present invention relates to the use of cationic starch to remove dissolved components or materials from liquid solution.
BACKGROUND OF THE INVENTION
There are currently a mind-boggling number of commercial/consumer oriented liquid products on the market, covering a vast range of product types. From a consumer perspective particularly, the color, flavor, and odor of certain products, and especially those products that are ingested, are often of significant importance. Blue coffee, or conceivably even green cola could be expected to meet with strong consumer resistance, and “bad” flavors and/or odors would be at least as unwelcome in commercial beverages and drinks.
In many instances, unwanted and/or unpleasant colors, odors and/or flavor characteristics are caused by the presence of certain components or impurities in a particular product. Often such impurities are by-products of the manufacturing process, and must be removed to make an acceptable product customers and consumers. One example of a product that must be de-colored through the removal of by-products is high fructose corn syrup. In the manufacturing of high fructose corn syrup, highly colored compounds are produced in the saccharification of starch step of the manufacturing process. These highly colored compounds can be removed using a number of techniques, such as by treatment with activated carbon, for example.
Although such impurities could conceivably be removed in the dry state, in fact in virtually all circumstances it is much easier to remove the impurities from a liquid phase. This could include removal of impurities from a liquid product or from a solution formed by dissolving a solid product in an appropriate liquid. In many cases the liquid will be water, but of course other liquids may be available.
Of course, for larger, particulate impurities, filtration processes can be used for removal. Screens, meshes and the like can be used for filtration, as can filtering media (also known as filter aid). The use of these filtration means is widespread, but of course these means work only for the removal of particulate impurities. However, as noted above, in many cases the impurities that impart unfavorable color, taste and odor characteristics are dissolved, and therefore are not removed, and generally cannot be removed, using such filtration methods. Furthermore, filtering media cannot be regenerated, and therefore has certain economic disadvantages due to replacement and disposal costs.
Dissolved impurities are typically removed from liquids using ion exchange and/or decolorization resins, which have the advantage of being regenerable using the appropriate acid and/or base. Such resins are typically expensive, however, and the use of corrosive chemicals and large quantities of rinse water (that must be treated prior to its return to the environment) in the regeneration process are disadvantages to their use.
Alternatively, impurities may be removed from solution using activated carbon, which is both porous (similar to filtering media) and slightly charged on its surface (analogous to ionic resins). Activated carbon also has disadvantages associated with its use; powdered activated carbon is very effective at removing impurities, but it is difficult to handle. Granular carbon is easier to work with, but is less effective at removing impurities. Furthermore, like filtering media, powdered carbon is a single-use material, and while granular carbon can be regenerated in specially designed furnaces, the furnaces are expensive to operate.
Another material that has been used in the art to remove solid particles from solution is cationic starch. The art has characterized this process as one of “flocculation”, which is defined as “[t]he combination or aggregation of suspended solid particles in such a way that they form small clumps of tufts resembling wool.” Hawley, G. G., ed.,
The Condensed Chemical Dictionary,
8
th
Ed., Van Nostrand Reinhold Company, New York, 1971. Pertinent patents describing the use of granular starch as a flocculation aid are U.S. Pat. No. 2,975,124 (Caldwell et al.); U.S. Pat. No. 2,995,513 (Paschall et al.); U.S. Pat. No. 3,423,312 (Blaisdell et al.); U.S. Pat. No. 3,835,114 (Hunt et al.); U.S. Pat. No. 3,842,005 (Moser et al.); U.S. Pat. No. 3,875,054 (Hunt et al.); and U.S. Pat. No. 3,962,079 (Hunt et al.). In each case, however, these disclosures relate to the use of the cationic starch for the removal of finely divided materials from a fluid by flocculation.
It is apparent from the foregoing that a need exists for a method for the removal of dissolved impurities from solution that does not involve a medium that 1) must be replaced after each use; 2) must be regenerated using corrosive chemicals; and 3) is not difficult and/or costly to recycle. It is the purpose of this invention to address this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure. Furthermore, it should be emphasized that the materials or components that one may wish to remove from a particular liquid phase solution may not be an “impurity” in the sense that the component to be removed is per se undesirable. For example, a particular metal may not be desirable in the final product from which the metal has been removed, but the metal itself may have value in its purified or isolated form.
SUMMARY OF THE INVENTION
The present invention relates to the inventor's surprising finding that cationic starch can remove dissolved impurities and other types of dissolved components or materials from a solution. In addition, the cationic starch can be safely and easily handled, and can also be recycled into a variety of beneficial end-uses, and the removed components may have value if they are separated from the cationic starch.
The process of the invention generally involves the mixing of granular cationic starch with the solution to be purified. This mixture is then heated to cause the cationic starch to gelatinize (this process is sometimes referred to as “cooking out the starch”). The cationic starch molecules are released from the starch granule, whereupon they complex with the impurities contained in solution. The treated solution is then separated from the cationic starch/impurities complex using standard methods used by those skilled in the art.
In an alternative embodiment, the starch can be pre-gelatinized before it is mixed with the solution to be treated. In the preferred embodiment, a small amount of filter media is added to assist the separation of the cationic starch/impurities complex from the treated solution.


REFERENCES:
patent: 2975124 (1961-03-01), Caldwell et al.
patent: 2995513 (1961-08-01), Paschall et al.
patent: 3423312 (1969-01-01), Blaisdell et al.
patent: 3835114 (1974-09-01), Hunt et al.
patent: 3842005 (1974-10-01), Moser et al.
patent: 3875054 (1975-04-01), Hunt et al.
patent: 3947354 (1976-03-01), Swanson et al.
patent: 3962076 (1976-06-01), Hunt et al.
patent: 4238329 (1980-12-01), Zievers
patent: 4288462 (1981-09-01), Hou et al.
patent: 4566909 (1986-01-01), Yong et al.
patent: 5008018 (1991-04-01), Raible
patent: 5575915 (1996-11-01), Nakamura et al.
patent: 6132625 (2000-10-01), Moffett
patent: 6307013 (2001-10-01), Chivers
patent: 763700 (1978-06-01), None
Wurzburg, O.B. (ed.), “Modified Starches: Properties and Uses”(1986) pp. 113-129, CRC Press, Inc.; Boca Raton, Florida, U.S.A.

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