E-digestion: a new renewable energy technology for Green Gas production (supervisors: Mieke Jansen and Bert Hamelers)
E-digestion is the bio-electrochemical conversion of CO2 into methane in a Microbial Electrolysis Cell (MEC). A MEC consists of an anode, where oxidation takes place, and a biocathode, a cathode with microorganisms on top, where reduction takes place. Our prime focus will be on the reduction of CO2 into methane at the biocathode.
Besides CO2, also protons and electrons are needed. These protons and electrons are formed in the anode where, water is oxidized into oxygen.
For these reactions energy is needed, however, this energy is not lost but stored within the formed methane. So, E-digestion is actually the conversion of electrical energy into chemical energy.
Proof-of-principle experiments have been performed on methane production in a MEC. We have shown that it is possible to produce methane in a continuous fashion, having a biocathode in a MEC. The challenge is to improve this technology and to design new reactor concepts. To do so, we focus on two key parameters: increasing the specific volumetric reactor productivity and decreasing the energy needed to produce methane. Key processes that are investigated are (i) the microbial consortium of the biocathode and its optimal operating conditions, (ii) mass transfer of protons, substrates and products to decrease energy losses, (iii) the diffusional losses of substrates and products over different membranes, and (iv) the type of electrode and material choice. If you feel like doing a thesis on this topic, don’t hesitate to contact us () and discuss the possibilities.
