Method for plasma activation of biochar material
A method for using plasma to activate biochar is disclosed where reactive gas(es) are excited by external power; biochar set on a sample holder is electrically biased or set at a floating potential so that charged particles of a certain type are attracted to the biochar, leading to intensive chemical reactions.
1. A method for activating biochar, the method comprising:
disposing biochar material in a vacuum chamber;
introducing a reactive gas comprising methane into the vacuum chamber at a pressure between 0.01 and 200 Torr; and
generating plasma in the vacuum chamber with an external RF power supply such that the biochar material is in contact with the plasma for a time period from about 10 seconds to about 30 minutes to form activated biochar.
2. The method of claim 1 , wherein the step of introducing a reactive gas into the vacuum chamber includes introducing oxygen.
3. The method of claim 1 , wherein the step of introducing a reactive gas into the vacuum chamber includes introducing methane mixed with argon.
4. The method of claim 1 , wherein the step of introducing a reactive gas into the vacuum chamber includes introducing silane.
5. The method of claim 1 , wherein the step of introducing a reactive gas into the vacuum chamber includes introducing a metallorganic gas.
6. The method of claim 1 , wherein the step of generating plasma in the vacuum chamber with an external RF power supply involves introducing power with a frequency of between 10 kHz and 300 GHz.
7. The method of claim 6 , wherein the step of generating plasma in the vacuum chamber with an external RF power supply involves introducing power with a frequency of 13.56 MHz.
8. The method of claim 1 , wherein the step of introducing a reactive gas involves introducing a mixture of gases.
9. The method of claim 8 , wherein the mixture of gases includes an inert gas.
10. The method of claim 1 , further comprising disposing the biochar material on a carrier.
11. The method of claim 10 , further comprising electrically biasing the carrier.
12. The method of claim 10 , further comprising setting the carrier at a floating electrical potential.
13. The method of claim 1 , further comprising disposing the biochar material on a conveyor.
14. The method of claim 1 , wherein the step of generating plasma involves first generating plasma with a first reactive gas, and second generating plasma using a different, second reactive gas.