Zirconium Phosphate Particles Having Improved Adsorption Capacity and Method Of Synthesizing The Same

• US 20100084330A1
• Filed: 09/29/2009
• Published: 04/08/2010
• Est. Priority Date: 10/03/2008
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Inventors: Wong, Raymond June-Hin
• Granted Patent: US 8,640,887 B2
• Time in Patent Office: Days
• US Class Current: 210/321.600
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00 ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: B01D 15/362 Cation-exchange
• CPC Class Codes: B01J 20/02 comprising inorganic material
• CPC Class Codes: B01J 20/0211 Compounds of Ti, Zr, Hf
• CPC Class Codes: B01J 20/0292 Phosphates of compounds other than those provided for in B01J20/048
• CPC Class Codes: B01J 20/048 containing phosphorus, e.g. phosphates, apatites, hydroxyapatites
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28069 Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: B01J 20/28083 being in the range 2-50 nm, i.e. mesopores
• CPC Class Codes: B01J 20/28085 being more than 50 nm, i.e. macropores
• CPC Class Codes: B01J 20/3078 Thermal treatment, e.g. calcining or pyrolizing
• CPC Class Codes: B01J 39/12 Compounds containing phosphorus
• CPC Class Codes: C01B 25/37 Phosphates of heavy metals
• CPC Class Codes: C01B 25/372 of titanium, vanadium, zirconium, niobium, hafnium or tantalum
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

Zirconium phosphate particles are synthesized by providing a solution of zirconium oxychloride in an aqueous solvent, adding at least one low molecular weight, oxygen containing, monofunctional, organic additive to the solution, and combining this solution with heated phosphoric acid or a phosphoric acid salt to obtain zirconium phosphate particles by sol gel precipitation.

Claims

1. A method of making zirconium phosphate particles comprising:

(a) combining zirconium oxychloride with at least one low molecular weight, oxygen containing, monofunctional, organic additive in an aqueous solvent to form a solution, and

(b) combining the solution obtained in (a) with phosphoric acid and removing the at least one low molecular weight, oxygen containing, monofunctional, organic additive to obtain zirconium phosphate particles by sol gel precipitation.

2. The method of claim 1, wherein the phosphoric acid in step (b) has a temperature of from about 90°

C. to about 100°

C.

3. The method of claim 1, wherein the low molecular weight, oxygen containing, monofunctional, organic additive forms a complex with zirconium ions in the solution.

4. The method of claim 1, wherein zirconium oxychloride is dissolved in the aqueous solvent and then the low molecular weight, oxygen containing, monofunctional, organic additive is added to form the solution of step (a).

5. The method of claim 1, wherein the zirconium oxychloride is present in the aqueous solvent at a concentration of from about 1.1 to about 1.5 g/ml.

6. The method of claim 1, wherein the zirconium oxychloride is present in the aqueous solvent up to a saturation concentration.

7. The method of claim 1, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is present in the aqueous solvent and then the zirconium oxychloride is added to form the solution of step (a).

8. The method of claim 3, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is present in the solution of step (a) in a molar amount sufficient so that substantially all of the zirconium ions in the solution are converted to the complex.

9. The method of claim 1, wherein the low molecular weight, oxygen containing, monofunctional, organic additive forms a soluble polymer complex with zirconium ions.

10. The method of claim 1, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is an alcohol, a carboxylate, or combinations thereof.

11. The method of claim 1, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is methanol, ethanol, propanol, isopropanol, acetic acid, propionic acid, or combinations thereof.

12. The method of claim 1, wherein the phosphoric acid comprises orthophosphoric acid.

13. The method of claim 1, further comprising:

(c) subjecting an aqueous slurry containing zirconium phosphate particles obtained from step (b) to a heat treatment carried out at a temperature of from about 90°

C. to about 100°

C.

14. The method of claim 13, wherein the heat treatment of step (c) is carried out for at least one hour.

15. The method of claim 13, wherein the aqueous slurry of step (c) is agitated during the heat treatment.

16. The method of claim 1, wherein in step (b), the solution obtained in step (a) and a solution of phosphoric acid are combined so that zirconium ions and phosphate groups are present in a molar ratio of about 1 to about 3 of zirconium to phosphate.

17. The method of claim 1, wherein the phosphoric acid has a molarity of from about 1.5 moles/L to about 3 moles/L.

18. The method of claim 1, further comprising combining the solution obtained in (a) with HCl before step (b).

19. The method of claim 1, further comprising isolating and drying the zirconium phosphate particles obtained in step (b) to obtain a free flowing powder.

20. A method of making zirconium phosphate particles having a controlled particle size comprising forming zirconium phosphate particles by sol gel precipitation by the method of claim 1, wherein the zirconium phosphate particles have a particle size and particle size distribution obtained by controlling one or more of the following parameters:

(a) the rate at which the solution of zirconium oxychloride and low molecular weight, oxygen containing, monofunctional, organic additive is added to the reaction vessel, (b) the rate at which the solution of phosphoric acid is added to the reaction vessel, (c) the pH of the solution of phosphoric acid, (d) the concentration of zirconium oxychloride, low molecular weight, oxygen containing, monofunctional, organic additive, or phosphoric acid in the reaction vessel, (e) the presence of HCl in the reaction vessel, (f) the speed of the agitator, or (g) any combination thereof.

21. A composition comprising zirconium phosphate particles, wherein the particles are formed by the method of claim 1.

22. The composition of claim 21, wherein the at least one low molecular weight, oxygen containing, monofunctional, organic additive is capable of forming a complex with zirconium ions.

23. The composition of claim 21, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is an alcohol, a carboxylate, or combinations thereof.

24. The composition of claim 21, wherein the low molecular weight, oxygen containing, monofunctional, organic additive is methanol, ethanol, propanol, isopropanol, acetic acid, propionic acid, or combinations thereof.

25. Zirconium phosphate (ZrP) particles having the following characteristics:

an average particle size of less than about 5 microns,

a BET surface area of at least 10 m²/g ZrP, and

an ammonia capacity in dialysate of about 7-9 mg NH₄—

N/g ZrP, at 10 mg/dL NH₄—

N.

26. A portable dialysis system comprising a container that contains the zirconium phosphate particles of claim 25.

27. Zirconium phosphate (ZrP) particles having the following characteristics:

an average particle size of about 25-65 microns,

a BET surface area of at least 10 m²/g ZrP, and

an ammonia capacity in dialysate of about 6-8 mg NH₄—

N/g ZrP, at 10 mg/dL NH₄—

N.

28. A dialysis cartridge comprising a cartridge that contains the zirconium phosphate particles of claim 27.

29. Zirconium phosphate (ZrP) particles having the following characteristics:

an average particle size of about 45-90 microns,

a BET surface area of at least 2 m²/g ZrP, and

an ammonia capacity in dialysate of at least about 15 mg NH₄—

N/g ZrP, at 20 mg/dL NH₄—

N.

30. The particles of claim 29 having a BET surface area of at least 10 m²/g ZrP.

31. The particles of claim 29 further having a pore volume of at least 0.0071 mL/g, a monolayer volume of at least 0.5 mL/g (STP), and a 20-80 nm pore size content of at least 30%.

32. A dialysis cartridge comprising a cartridge that contains the zirconium phosphate particles of claim 29.

33. Zirconium phosphate (ZrP) particles having the following characteristics:

a pore volume of at least 0.0071 mL/g,

a monolayer volume of at least 0.5 mL/g (STP), and

a 20-80 nm pore size content of at least 30%.

34. A dialysis cartridge comprising a cartridge that contains the zirconium phosphate particles of claim 33.