Electrochemical CO2 capture and mineralisation

Carbon capture from power station exhaust gases is widely accepted as being an essential part of any global policy to control climate change due to increasing levels of carbon dioxide in the atmosphere. However, the usual way of capturing waste carbon dioxide uses aqueous solutions of amines and has been calculated to consume 25-30% of the energy generated by a power station. In this project we will build on preliminary results to develop an alternative electrochemical approach to carbon capture.

We have already shown that by using a low surface area aluminium anode (coated in permeable graphite) along with a platinum cathode, electrolysis of an aqueous solution of sodium chloride under an atmosphere of 5% carbon dioxide in nitrogen (to simulate power station flue gas) resulted in generation of hydrogen at the platinum cathode and precipitation of carbonated aluminium oxide. This process has a number of highly desirable characteristics:

The electricity can be generated from renewable sources.
The coproduction of hydrogen provides a high value by-product.
The aqueous sodium chloride electrolyte is effectively just sea water.
Waste aluminium is available which could be used to avoid the expense and carbon dioxide emissions associated with using pristine aluminium.
The carbon dioxide is captured as a solid which is easier to store than gaseous carbon dioxide and which may have commercial applications.

This studentship will allow this project to be continued and will involve:

Understanding and optimising the electrochemical cell design
Demonstrating the use of real sea water and waste aluminium
Investigation of other materials for the anode, cathode and electrolyte
Using a solar panel to drive the electrochemical process
Calculation of the overall energetics of the process and demonstration of its carbon negative nature if renewable electricity is used.