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https://hdl.handle.net/123456789/1810| Τύπος: | Ανακοίνωση σε συνέδριο |
| Τίτλος: | Bioelectrochemical reduction of carbon dioxide to methane |
| Συγγραφέας: | [EL] Βασιλειάδου, Ιωάννα[EN] Vasiliadou, Ioanna [EL] Καλογιάννης, Αχιλλέας[EN] Kalogiannis, Achilleas [EL] Σπυριδωνίδης, Απόστολος[EN] Spyridonidis, Apostolos [EL] Κατσαούνης, Αλέξανδρος[EN] Katsaounis, Alexandros [EL] Σταματελάτου, Αικατερίνη |
| Ημερομηνία: | 14/07/2021 |
| Περίληψη: | Residual biomass, comprise a renewable energy source, that can be recovered through anaerobic digestion into biogas. Biogas upgrade, may lead to pure biomethane production, which can be used as vehicle fuel and natural gas substitute. Biogas upgrade is currently conducted by separating CO2 from biogas using energy-consuming physicochemical processes or using an external H2 source for biological CO2 conversion into CH4 (Muñoz et al., 2015). Bio-electrochemical biogas upgrade, is an innovative method, in which CO2 is converted into CH4 by methanogenic microorganisms, in the bio-cathode of a Microbial Electrochemical Cell (MEC), using electric current as energy source, while no H2 supply is required (Cheng et al., 2009). The goal of the present study, was the development of a novel technology for biogas upgrade, by coupling biological and electrochemical processes, using the concept of microbial electrochemistry. A special designed H-type MEC, consisting of a cathodic and an anodic cell (separated by a proton exchange membrane, Nafion117), has been used (Figure 1). The cathode chamber, was inoculated with a mixed culture of methanogenic microorganisms previously acclimated under biogas bio-upgrade conditions. The H-MEC, operated in a three-electrode configuration (working: carbon rod, counter: IrO2-RuO2/Ti, reference Ag/AgCl) with a potentiostat, which poised the biocathode at -0.7 V vs. standard hydrogen electrode (SHE) and monitored the current demand. The synthetic medium (Bassani et al., 2016) of the bio-cathode, was initially sparged with a gas mixture of N2/CO2, while the anode was sparged with N2. After 14 days of acclimation under electrochemical conditions, the catholyte and anolyte of the MEC were resupplied with N2/CO2 gas mixture and N2 gas, respectively, and the MEC’s operation started. CO2 conversion to CH4 in the cathode chamber was evaluated periodically, by analyzing both gas and liquid phases. Cyclic voltammetry runs were performed, in the range of -0.9 to 1.2 V (5 mV/s) in order to determine whether the methanogenic culture was adapted to the electrochemical conditions. Figure 1. Microbial Electrochemical Cell set-up. As shown in Figure 2(a), after 14 days of acclimation, microorganisms were interacting with the carbon-electrode, producing a greater catalytic wave, related to hydrogen production, as compared to the corresponding CV of the initial inoculum. It should be noted that at cathode potential -0.7 V vs. SHE, the reduction of CO2 into methane could be done via direct electron transfer as well as indirectly by using the (bio)electrochemically produced hydrogen at the bio-cathode (van Eerten-Jansen et al., 2015). H2 and CH4 production rates were 0-1.2 and 8.2-6.8 mmol m-2 d-1, respectively, during the first days of the two operating cycles, with an electron capture efficiency for CH4 (Coulombic efficiency, CE) of 50-54% (Figure 2c). Thereafter, the MEC’s efficiency was reduced, probably due to the diffusion of O2 to the cathode chamber through the membrane, produced by the water oxidation process in the anode chamber (Batlle-Vilanova et al., 2015). The CO2 reduction rate was about 200 mmol m-2 d-1 during the operation. Figure 2. (a) CVs at the beginning and at the end of acclimation period, (b) CVs at the beginning of the operating cycles, (c) Time course of current and coulombic efficiency. Vertical dashed lines indicate biocathode’s resupply with N2/CO2. This study showed that electromethanogenesis can be used to convert electrical current into a biofuel (CH4) as well as serving as a method for the capture of CO2. The wise use of electric energy, for biogas upgrade, is undoubtedly an attractive challenge, yielding substantial ecological and economic benefits. |
| Γλώσσα: | Αγγλικά |
| Τόπος δημοσίευσης: | Αλεξανδρούπολη, Ελλάδα |
| Σελίδες: | 2 |
| Θεματική κατηγορία: | [EL] Ανανεώσιμη ενέργεια, Αειφορία και Περιβάλλον[EN] Renewable Energy, Sustainability and the Environment |
| Λέξεις-κλειδιά: | biomethane; bioelectrochemical; biofuel; biogas upgrade; microbial electrochemical cell; electro-methanogenesis; methanogenic microorganisms; methane production |
| Κάτοχος πνευματικών δικαιωμάτων: | © The Author(s) 2021 |
| Όνομα εκδήλωσης: | 2nd Online Symposium on Circular Economy and Sustainability |
| Τοποθεσία εκδήλωσης: | Online Event, Alexandroupolis, Greece |
| Ημ/νία έναρξης εκδήλωσης: | 14/07/2021 |
| Ημ/νία λήξης εκδήλωσης: | 16/07/2021 |
| Σημειώσεις: | This research is co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Bioelectrochemical biogas upgrade into methane (CH4): An innovative method of carbon dioxide (CO2) conversion” (MIS 5050548).” |
| Εμφανίζεται στις συλλογές: | Ερευνητικές ομάδες |
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