Removal of heavy metals and heavy metal radioactive isotopes from liquids

• US 4,902,665 A
• Filed: 07/29/1988
• Issued: 02/20/1990
• Est. Priority Date: 04/07/1986
• Status: Expired due to Term

• Current Assignee: Iso-Clear Systems Corporation
• Original Assignee: Iso-Clear Systems Corporation
• Inventors: Elfline, Geraldine S.
• Primary Examiner(s): GARVIN, PATRICK
• Application Number:
  US07/225,936
• Time in Patent Office: 571 Days
• Field of Search: 502/404, 502/402
• US Class Current: 502/402
• CPC Class Codes: G21F 9/10 by flocculation
• CPC Class Codes: G21F 9/12 by absorption; by adsorption; by ion-exchange

Abstract

A method of treating a heavy metal and/or a radioactive metal-containing natural water or liquid such as a radioactive metal-containing wastewater stream, a potable water supply containing naturally-occurring radioactive elements, an oil containing one or more radioactive metals, or other nuclear metal-bearing liquid by contacting the radioactive heavy metal-containing liquid with a water-insoluble carboxylated cellulose-transition metal oxide mixture to separate the heavy metals from the liquid. The heavy metal and radioactive heavy metals precipitate from the liquid onto the cellulose material to form a radioactive metal-laden solid material. The radioactive metal-laden solid then is air-dried, calcined and/or admixed with a leach-resistant matrix, such as grout or asphalt, for suitable disposal. The process has been found to be unexpectedly effective on heavy metal contaminated waters and particularly on radioactive natural waters, radioactive wastewaters or any other liquid containing one or more radioactive heavy metal ions such as U, Ce, Sr, Ru, Ra, Np and Tc.

Claims

1. A method of manufacturing a heavy metal-removing mixture of a water-penetrable, insoluble carboxylated cellulose and a plurality of insoluble particles of a heavy metal interactant comprising:

dispersing solid particles of a heavy metal interactant in a carrier liquid;

cross-linking a water-soluble form of a carboxylated cellulose to insolubilize the carboxylated cellulose while in close proximity to said heavy metal interactant particles and entrap some of the heavy metal interactant particles within the insolubilized carboxylated cellulose to form said heavy metal-removing mixture.

2. The method of claim 1 wherein the heavy metal interactant is an absorbent, adsorbent, reactant or an ion exchange material for heavy metals.

3. The method of claim 2 wherein the heavy metal interactant is a transition metal oxide.

4. The method of claim 3 wherein the heavy metal oxide is manganese dioxide.

5. The method of claim 1 wherein the insoluble carboxylated cellulose is a salt of carboxymethylcellulose.

6. The method of claim 5 wherein the carboxymethylcellulose salt is the aluminum, chromium, titanium, copper, silicon or iron salt of carboxymethylcellulose.

7. The method of claim 6 wherein the insoluble carboxymethylcellulose is aluminum carboxymethylcellulose or titanium carboxymethylcellulose.

8. The method of claim 1 wherein the heavy metal interactant comprises solid particles having a particle size of 0.1 to 100 microns.

9. The method of claim 8 wherein the heavy metal interactant comprises solid particles having a particle size of 0.1 to 50 microns.

10. The method of claim 9 wherein the heavy metal interactant comprises solid particles having a particle size of 0.1 to 10 microns.

11. The method of claim 1 wherein the metal-removing mixture is in the form of water-penetrable spherical beads.

12. The method of claim 11 wherein the spherical beads include a colloidal heavy metal interactant homogenously interspersed within the insoluble carboxylated cellulose.

13. The method of claim 1 wherein the soluble form of a carboxylated cellulose is a salt of carboxymethylcellulose.

14. The method of claim 13 wherein the salt of carboxymethylcellulose is sodium carboxymethylcellulose.

15. The method of claim 1 wherein the soluble form of a carboxylated cellulose is insolubilized by reaction with a multivalent metal cation.

16. The method of claim 15 wherein the multivalent metal cation is aluminum, chromium, titanium, copper, silicon, or iron.

17. The method of claim 16 wherein the multivalent metal cation is aluminum or titanium.

18. The method of claim 1 including forming the particles of heavy metal interactant by dissolving a soluble form of the heavy metal interactant in the carrier liquid, and thereafter reacting the soluble form of the heavy metal interactant with a sufficient quantity of a suitable reactant to insolubilize the heavy metal interactant.

19. The method of claim 18 wherein the soluble form of the heavy metal interactant is an inorganic salt or a soluble polymer.

20. The method of claim 19 wherein the inorganic salt is potassium permanganate.

21. The method of claim 18 wherein the reactant is an oxidizing agent, reducing agent or multifunctional crosslinking agent.

22. The method of claim 21 wherein the reactant is hydrogen peroxide.

23. The carboxylated cellulose-heavy metal interactant mixture manufactured by the process of claim 2.

24. The product made by the process of claim 6.

25. An insoluble cross-linking carboxylated cellulose having uniformly distributed throughout its interior a plurality of finely divided water-insoluble particles of a heavy metal interactant.