Formulation and method for preparing gels comprising hydrous cerium oxide
View Patent ↗Formulations useful for preparing hydrous cerium oxide gels contain a metal salt including cerium, an organic base, and a complexing agent. Methods for preparing gels containing hydrous cerium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including cerium, an organic base, and a complexing agent.
1. A formulation for preparing gels, the formulation consisting essentially of:
a cerium metal salt;
an organic base; and
a complexing agent,
wherein a mole ratio of the organic base to the cerium is greater than 1.5;
wherein a concentration of the cerium ranges from about 0.5 M to about 1.0 M, a concentration of the organic base ranges from about 1.3 M to about 2.0 M, the organic base comprises hexamethylenetetramine, the complexing agent comprises urea, and the metal salt comprises cerium ammonium nitrate.
2. The formulation of claim 1 , wherein the mole ratio of the organic base to the cerium ranges from about 2 to about 3.3.
3. The formulation of claim 2 , further comprising a source of hydroxide, wherein a mole ratio of the hydroxide to the cerium ranges from greater than 0 to about 1, and the source of hydroxide comprises ammonium hydroxide.
4. The formulation of claim 1 , further comprising a source of hydroxide.
5. The formulation of claim 4 , wherein a mole ratio of the hydroxide to the cerium ranges from greater than 0 to about 1.
6. The formulation of claim 4 , wherein the source of hydroxide comprises ammonium hydroxide.
7. The formulation of claim 1 , wherein a mole ratio of the organic base to the complexing agent is about 1.
8. The formulation of claim 1 , further comprising a source of hydroxide, wherein a mole ratio of the hydroxide to the cerium ranges from greater than 0 to about 1, and the source of hydroxide comprises ammonium hydroxide.
9. A method of preparing gels comprising hydrous cerium oxide, the method comprising heating a volume of a formulation to a temperature sufficient to induce gel formation, wherein the formulation consists essentially of:
a cerium metal salt;
an organic base; and
a complexing agent,
wherein a mole ratio of the organic base to the cerium is greater than 1.5;
wherein a concentration of the cerium ranges from about 0.5 M to about 1.0 M, a concentration of the organic base ranges from about 1.3 M to about 2.0 M, the organic base comprises hexamethylenetetramine, the complexing agent comprises urea, and the metal salt comprises cerium ammonium nitrate.
10. The method of claim 9 , wherein the volume of the formulation is heated to a temperature of at least about 60° Celsius.
11. The method of claim 10 , wherein the volume of the formulation is heated to a temperature of about 60° Celsius to about 90° Celsius.