Our current regeneration process utilizes heating an oven to 80°C or 176°F, to release trapped CO² from the sponge; this temperature is notably below the boiling point of water. 

We found this to be successful as we preformed a "bubble test" to verify results.

A component of this chemical reaction is that Ammonium Carbonate is susceptible to Thermal Decomposition. This means that the introduction of heat in the range from 80-120°C has the ability to break the bond between the aqueous Ammonium Carbonate and its contained CO².

Below is the chemical equation for the Thermal Decomposition at ~ 80°C.

(NH⁴​​)2​CO³​→(80°C)→C​²NH³​+CO²+H²​O 

For our trials we used three sponges. Sponge A is soaked in Ammonium Bicarbonate and exposed to airborne CO². Sponge B is soaked in Ammonium Bicarbonate and is not exposed to airborne CO². Sponge C is not soaked in Ammonium Bicarbonate but is exposed to airborne CO². Sponges B and C are meant to act as control tests, while Sponge A is our main experimental test.  

We found our trials to be successful as shown through the "bubble test". Following the 30 minute exposure trial, we placed Sponges A, B, and C in water filled containers to be heated in an oven. We initially noticed that Sponge A displayed more buoyancy than Sponges B and C likely due to the oxygen in the trapped CO². Furthermore, when all were heated to 80°C, Sponge A bubbled the most in the water. While all tests had some bubbling as is the case with heating water and as the result of some unaccounted particles trapped in the sponges, this excess of bubbling in A, when compared to the other tests, B and C, is an indicator for CO² release, thus proving a successful test.

With larger filter surface areas we will require a larger system for regeneration. Additionally we wish to make our process more measurable, consistent, and streamlined.

To do so we will make an induction heating system using metal coils with sensors and controls to accurately heat to certain temperatures to facilitate consistent, fast release of CO².

We will also experiment with an early collection/storage process of the released CO².

We will eventually have a very consistent and efficient onboard process of professional induction heating integrated into our custom filter designs to allow for mid flight regeneration. Coupled with this, will be an onboard collection/storage process to capture this released CO².

The SkyTrees will carry canisters that will fill with released CO² and drop these canisters off to a separate "mothership" mid flight and obtain a new canister from the aforementioned "mothership".