Activated, coal-based carbon foam
An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the “dirty” and friable particulate activated carbon foam materials of the prior art.
1. An activated carbon foam comprising a surface area ranging from about 10 m 2 /g to about 25 m 2 /g manufactured by the process comprising:
heating swellable particulate coal to a temperature between about 300° C. and about 700° C. under a non-oxidizing atmosphere at a pressure ranging from about 25 psi to about 500 psi and soaking at said temperature for from about 10 minutes to about 12 hours to produce a carbon foam; and
activating said carbon foam by flowing an activation agent through said carbon foam for a period ranging from about 1 hour to about 12 hours at a temperature ranging from about 600° C. to about 1200° C., thus producing an activated carbon foam.
2. The activated carbon foam of claim 1 , wherein the activating agent comprises ozone.
3. The activated carbon foam of claim 1 , wherein the activating agent comprises carbon dioxide.
4. The activated carbon foam of claim 1 , wherein the process further comprises the step of carbonizing the carbon foam to form a carbonized foam by heating to a temperature ranging from about 600° C. to about 1600° C. in an inert atmosphere and holding at the temperature for a period of time ranging from about 1 hour to about 3 hours.
5. The activated carbon foam of claim 1 , wherein the process further comprises the step of graphitizing said carbon foam by heating said carbon foam to a temperature ranging from about 1700° C. to about 3000° C. in an inert atmosphere and holding at the temperature for a period of time less than about 1 hour.
6. An activated carbon foam comprising an open-celled carbon foam having a density up to about 0.8 g/cc, a surface area from about 10 m 2 /g to about 25 m 2 /g, wherein a surface of the open-celled carbon foam is sealed.
7. The activated carbon foam of claim 6 , wherein the carbon foam has a density between about 0.1 g/cc and about 0.8 g/cc.
8. The activated carbon foam of claim 6 , wherein the carbon foam has a surface area between about 10 m 2 /g and about 25 m 2 /g.
9. The activated carbon foam of claim 6 , wherein the carbon foam has a surface area between about 15 m 2 /g and about 20 m 2 /g.
10. The activated carbon foam of claim 6 , wherein the carbon foam is impregnated with a polymer.
11. The activated carbon foam of claim 6 , wherein the carbon foam is impregnated with an epoxy resin.
12. The activated carbon foam of claim 6 , wherein the carbon foam is impregnated with a petroleum pitch.
13. The activated carbon foam of claim 1 , wherein the activation agent is introduced to said carbon foam at a rate in the range of about 1 ft 3 /minute to about 10 ft 3 /minute.