Methods for biodegradation separation of natural fibers to release particulate contamination

• US 5,597,728 A
• Filed: 10/11/1994
• Issued: 01/28/1997
• Est. Priority Date: 07/23/1993
• Status: Expired due to Term

• Current Assignee: Texas Tech University (Texas Tech University System)
• Original Assignee: Bobby G. Wyatt, Caryl H. Wyatt
• Inventors: Wyatt, Caryl H., Wyatt, Bobby G.
• Primary Examiner(s): PADEN, CAROLYN A
• Application Number:
  US08/319,072
• Time in Patent Office: 840 Days
• Field of Search: 435/262, 435/262.5, 435/263, 435/264, 435/267, 435/821, 435/277, 252/174.12, 8/408, 210/611, 210/922, 210/682, 210/691, 210/751, 588/1, 588/2, 588/9, 588/20, 536/127, 536/56, 536/20
• US Class Current: 435/262.5
• CPC Class Codes: C02F 1/681 by addition of solid materials for removing an oily layer on water
• CPC Class Codes: C07G 99/0022 derived from hydrocarbons
• CPC Class Codes: C12P 19/14 produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase , e.g. by cellulase, hemicellulase
• CPC Class Codes: G21F 9/30 Processing separating different isotopes of the same chemical element B01D59/00
• CPC Class Codes: Y10S 435/821 Microorganisms used in the destruction of hazardous or toxic waste

Abstract

A method is presented for releasing petroleum and hydrocarbon products sorbed onto or entrained by natural fibers in an aqueous medium through the use of enzymes to degrade the natural fiber sorbents utilized for oil spill cleanup, the method provides an opportunity for achieving responsible separation of oil from oil spill sorbent materials. Natural fibers which have been utilized to adsorb petroleum and hydrocarbon products are separated from these petroleum and hydrocarbon products by reducing the natural fiber links to the point that the adsorbed or entrained oil no longer has sufficient binding surface or fiber link to remain held by the fibers, thus float to the surface of the aqueous medium. Aqueous medium enzyme compositions are provided which are suitable for degrading natural fibers inclusive of cellulose-based and protein-based fibers resulting in release of adsorbed, absorbed and/or entrained radioactive contaminants.

Claims

1. A method for separating radioactive contaminants adsorbed or entrained onto organic natural fibers, comprising:

admixing organic natural fibers containing radioactive contaminates with an effective amount of enzymes to degrade the organic natural fibers in an aqueous medium, said enzymes capable of degrading the fibers;

maintaining the admixture at a pH of from about 3.5 to about 8.0 and a temperature of from about 20°

C. to about 60°

C., as is sufficient to maintain the enzymes activity;

degrading the organic natural fibers by enzyme breakage of molecular chains constituting the fibers;

destroying the natural fiber integrity, fiber lengths sufficient for release of the radioactive contaminants;

removing the radioactive contaminants from the aqueous medium; and

disposing of the aqueous medium and degraded fibers.

2. The method according to claim 1 for separating radioactive contaminants adsorbed or entrained on organic natural fibers wherein the aqueous medium admixture of organic natural fibers containing radioactive contaminants and enzymes are agitated for enhancing the degradation of the organic natural fibers.

3. The method according to claim 1 wherein the aqueous medium containing radioactive contaminates and enzymes are removed from a reaction chamber with the enzymes being reused for additive degradation of organic natural fibers, reused enzymes being made up to about 10% by volume of fresh enzyme solution introduction to the reaction mixture.

4. The method according to claim 1 wherein the enzyme concentration in the aqueous medium containing said fibers is from about 4% to about 30% on weight of goods.

5. The method according to claim 1 wherein the organic natural fibers are comprised of cellulose or modified cellulose materials and the enzymes are comprised of cellulases.

6. The method according to claim 5 wherein the cellulose or modified cellulose materials can contain up to about 40% by weight of man-made fibers or other organic natural fibers.

7. Method according to claim 1 wherein the radioactive contaminates are absorbed or entrained on organic natural fibers contained within fabrics constructed of said fibers.

8. A method for separating radioactive contaminants adsorbed or entrained on cellulosic fibers or modified cellulosic fibers, comprising:

admixing the cellulosic fibers containing radioactive contaminants with cellulases in sufficient concentration to degrade the cellulosic fibers in an aqueous medium;

maintaining the mixture at a pH of from about 4 to about 6.5 at a temperature of from about 20°

C. to about 60°

C., as is sufficient to maintain the cellulase activity;

agitating the aqueous medium containing the cellulases and cellulosic fibers containing the radioactive contaminants;

degrading the cellulosic fibers by breakage of cellulose molecule chains;

reducing cellulose chain links by destroying the β

1-4 glycosidic bonds of cellulose thus reducing the length of the cotton fibers and releasing the radioactive contaminants;

separating the released radioactive contaminant in liquid form from the aqueous medium surface; and

disposing of the degraded fibers, glucose, oligosaccharides, and the aqueous medium.

9. The method according to claim 8 wherein the fibers are substantially reduced to glucose and oligosaccharides in aqueous medium.

10. The method according to claim 9 wherein the released radioactive contaminants are separated from the aqueous medium by ion capture.

11. The method according to claim 9 wherein the released radioactive contaminants are separated from the aqueous medium by vitrification.

12. The method according to claim 8 wherein the enzyme concentration in the aqueous medium containing said fibers is from about 0.01% to about 0.025% and greater by weight to total volume.

13. The method according to claim 8 wherein the Cellulase concentration in the aqueous medium containing said fibers is from about 4% to about 30% on weight of goods.