Remediation material and remediation process for sediments

• US 20020130085A1
• Filed: 01/15/2002
• Published: 09/19/2002
• Est. Priority Date: 03/26/1997
• Status: Abandoned Application

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Douglas, Grant Brian
• Application Number:
  US10/050,332
• Publication Number:
  US 20020130085A1
• Time in Patent Office: Days
• US Class Current: 210/679
• CPC Class Codes: B01J 20/0207 Compounds of Sc, Y or Lanthanides
• CPC Class Codes: B01J 20/0211 Compounds of Ti, Zr, Hf
• CPC Class Codes: B01J 20/0288 Halides of compounds other than those provided for in B01J20/046
• CPC Class Codes: B01J 20/0292 Phosphates of compounds other than those provided for in B01J20/048
• CPC Class Codes: B01J 20/0296 Nitrates of compounds other than those provided for in B01J20/04
• CPC Class Codes: B01J 20/04 comprising compounds of alkali metals, alkaline earth metals or magnesium
• CPC Class Codes: B01J 20/046 containing halogens, e.g. halides
• CPC Class Codes: B01J 20/12 Naturally occurring clays or bleaching earth
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/18 Synthetic zeolitic molecular sieves
• CPC Class Codes: B09C 1/00 Reclamation of contaminated soil
• CPC Class Codes: B09C 1/08 chemically
• CPC Class Codes: Y10S 210/906 Phosphorus containing
• CPC Class Codes: Y10S 210/911 Cumulative poison
• CPC Class Codes: Y10S 210/912 Heavy metal
• CPC Class Codes: Y10S 210/913 Chromium

Abstract

A material and method for removal of environmental oxyanions (and especially phosphates), the material comprising a substrate such as a clay modified with complexing elements selected from Group IIIB, Group IVB, and lanthanide elements (or a mixture of such elements). The resultant modified substrate can bind oxyanions and make them unavailable for utilisation in the environment; in the case of phosphates, by algae and the like. The method includes forming a capping of material at the sediment/water interface, applying the material in the form of pellets at the sediment/water interface, or injecting the pellets into the sediment.

Claims

1. A method for remediating matter by removing phosphorus and oxyanion pollutants therefrom, the matter being such as sediments in waterways and catchments, or effluent from sewage treatment plants, industry or aquaculture, the method including the step of contacting the matter with a substrate modified with complexing element(s) selected from Group IIIB, lanthanides, and Group IVB elements.

2. A method as claimed in claim 1 including adding a soluble salt of the complexing element selected from Group IIIB and Group IVB elements.

3. A method as claimed in claim 2 wherein the salt is a chloride salt or a nitrate salt or a mixture of chloride and nitrate salts of the complexing element.

4. A method as claimed in claim 3 further including the addition of a divalent salt such as a calcium salt, or a trivalent salt.

5. A method as claimed in any one of the preceding claims wherein the substrate has a cation exchange capacity (CEC) of greater than 30 milliequivalents per 100 grams (meq/100 g).

6. A method as claimed in claim 5 wherein the substrate has a cation exchange capacity (CEC) of greater than 100 meq/100 g.

7. A method as claimed in claim 6 wherein the substrate has a cation exchange capacity (CEC) of greater than and 150 meq/100 g.

8. A method as claimed in any one of claims 5 to 7 wherein the substrate is a natural or synthetic mineral substrate or a mixture of substrates.

9. A method as claimed in claim 8 wherein the mineral substrate is an expandable clay such as saponite, bentonite or vermiculite, or a fibrous, chain-like related clay mineral such as attapulgite, sepiolite or palygorskite, or a mixture of any such substrates.

10. A method as claimed in claim 9 wherein the mineral substrate includes zeolite.

11. A method as claimed in any one of claims 8 to 10 wherein the mineral substrate was pretreated with a concentrated acid (e.g. HCl, H₂SO₄) to remove a large proportion of the interlayer cations, before being modified with said complexing element.

12. A method as claimed in any one of the preceding claims wherein the complexing element comprises one of more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, yttrium, ytterbium, lutetium, zirconium, and hafnium.

13. A method as claimed in claim 12 wherein the complexing element comprises lanthanum.

14. A method as claimed in claim 12 wherein the complexing element comprises zirconium.

15. A method as claimed in claim 12 wherein the complexing element comprises a mixture of lanthanum and zirconium.

16. A method as claimed in any one of the preceding claims wherein the sediment remediation material is altered by the addition of organic and/or inorganic ligands to alter its chemical properties for a particular application.

17. A method as claimed in any one of the preceding claims wherein the remediation material is applied as a dry powder, as pellets, or as a wet slurry to the surface of a waterbody.

18. A method as claimed in any one of the preceding claims wherein the remediation material is applied directly to the surface of bottom sediments of a waterbody.

19. A method as claimed in any one of the preceding claims wherein the remediation material is injected into the bottom sediments of a waterbody.

20. A method as claimed in any one claims 1 to 16 wherein the remediation material forms a capping layer over the surface of bottom sediments of the water body.

21. A method as claimed in claim 20 wherein the capping layer has a thickness in the range of between 0.5 mm and 5 mm.

22. A method as claimed in any one of claims 1 to 16 wherein the remediation material is sandwiched between geotextiles such as water permiable membranes or woven plastic cloth such as woven PVC cloth or textile.

23. A method as claimed in any one of claims 1 to 16 wherein the remediation material is pelletised and sandwiched between weave net surfaces having apertures smaller than the pellets, in order to accomodate a high solute flow while retaining the remediation material therein.

25. A remediation material as claimed in claim 24 wherein the substrate has a cation exchange capacity (CEC) of greater than 30 milliequivalents per 100 grams (meq/100 g).

26. A remediation material as claimed in claim 24 wherein the substrate has a cation exchange capacity (CEC) of greater than 100 meq/100 g.

27. A remediation material as claimed in claim 24 wherein the substrate has a cation exchange capacity (CEC) of greater than and 150 meq/100 g.

29. A remediation material as claimed in claim 28 wherein the mineral substrate is an expandable clay such as saponite, bentonite or vermiculite, or a fibrous, chain-like related clay mineral such as attapulgite, sepiolite or palygorskite, or a mixture of any such substrates.

30. A remediation material as claimed in claim 28 wherein the mineral substrate includes zeolite.

24. A remediation material for use in reducing phosphorus and oxyanion pollutant loadings in matter, the remediation material comprising a substrate modified with a complexing element(s) selected from the Group IIIB, lanthanides, and Group IVB elements.

28. A remediation material as claimed in any one of claims 24 to 27 wherein the substrate is a natural or synthetic mineral substrate or a mixture of mineral substrates.

31. A remediation material as claimed in any one of claims 28 to 30 wherein the mineral substrate was pre-treated with a concentrated acid (e.g. HCl, H₂SO₄) to remove a large proportion of the interlayer cations, before being modified with said complexing element.

32. A remediation material as claimed in any one of claims 24 to 31 wherein the element is selected from one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, yttrium, ytterbium, lutetium, zirconium, and hafnium.

33. A remediation material as claimed in claim 32 wherein the complexing element comprises lanthanum.

34. A remediation material as claimed in claim 32 wherein the complexing element comprises zirconium.

35. A remediation material as claimed in claim 32 wherein the complexing element comprises a mixture of lanthanum and zirconium.

36. A remediation material as claimed in any one of claims 24 to 35, altered by the addition of organic and/or inorganic ligands.

37. A sediment remediation process substantially as herein described, with reference to the description of the embodiment.

38. A remediation material substantially as herein described, with reference to the description of the embodiment.