Sustainable, facile separation of the molten carbonate electrolysis cathode product
A process for the separation of electrolyte from the carbon in a solid carbon/electrolyte cathode product formed at the cathode during molten carbonate electrolysis. The processes allows for easy separation of the solid carbon product from the electrolyte without any observed detrimental effect on the structure and/or stability of the resulting solid carbon nanomaterial.
1. A process for preparing an aerogel by separating electrolyte from a solid carbon/molten electrolyte mixed product removed from the cathode of a carbonate electrolysis, the process comprising:
(i) applying a force to compress the solid carbon/molten electrolyte mixed product to remove the electrolyte, in which the force compresses the solid carbon/molten electrolyte mixed product directly on the cathode in an electrolysis chamber;
(ii) removing the force; and
(iii) isolating the aerogel.
2. The process according to claim 1 , wherein steps (i) and (ii) are repeated two, three or four times, prior to step (iii).
3. The process according to claim 1 , wherein the compression is conducted at a pressure of between 10 psi and 100,000 psi.
4. The process according to claim 1 , wherein the electrolyte is removed through an interface with pores.
5. The process according to claim 4 , wherein the interface with pores comprises a porous carbon felt, a graphite felt, a metal mesh, a porous or sieve ceramic, or any combination thereof.
6. The process according to claim 4 , wherein the pore size of the interface is between 10 μm and 10 mm.
7. The process according to claim 1 , wherein the process is conducted at a temperature between 399° C. and 900° C.
8. The process according to claim 1 , wherein the process further comprises applying a vacuum during the separation process.
9. The process according to claim 8 , wherein the process is conducted at a pressure between 0.1 and 0.9 atmospheres.
10. The process according to claim 8 , wherein the process is conducted at a pressure less than 0.1 atmospheres.
11. The process according to claim 1 , wherein the process is conducted under a gas that is free of oxygen.
12. The process according to claim 11 , wherein the gas is selected from nitrogen, carbon dioxide, argon, methane, ammonia, hydrogen, hydrogen sulfide, and any combination thereof.
13. The process according to claim 1 , wherein the mixed product is cooled after its formation by electrolysis and reheated prior to the compression.
14. The process according to claim 1 , wherein the electrolyte is not a flowing electrolyte.
15. The process according to claim 1 , wherein the electrolyte is not recirculated via a recirculation loop.
16. The process according to claim 1 , wherein the aerogel has an average thickness greater than 1 millimeter.
17. The process according to claim 1 , wherein the aerogel comprises greater than about 80% carbon nano-materials.
18. The process according to claim 1 , wherein the aerogel comprises greater than about 95% carbon nano-materials.
19. The process according to claim 1 , wherein the aerogel is formed from raw carbon nano-material that agglomerates during the carbonate electrolysis and the isolating comprises filtering the aerogel with a filter having pores larger than the raw carbon nano-material.
20. The process according to claim 1 , wherein the solid carbon/molten electrolyte comprises a paste.
21. The process according to claim 1 , wherein the aerogel can be repeatedly compressed without compromising the structure and/or stability of the resulting aerogel.