Ghaderikia, Amin
Bioelectrochemical methane production, known as electromethanogenesis, provides an emerging technology for carbon recycling via the conversion of carbon dioxide to methane with the additional benefit of simultaneous organic waste reduction. Bioelectrochemical conversion reactions in an electromethanogenic microbial electrolysis cell (MEC) are catalyzed by electro-active biofilm on the electrodes; hence, biofilm formation has a key role in system performance. In this study, the objective was to evaluate the impacts of different start-up strategies on the performance of methane production from a complex waste, cattle manure in bioelectrochemical reactors. At first, the focus was on the performance of an electromethanogenic MEC and designed experiments for providing a comparative analysis of the impact of biofilm formation upon feeding a simple substrate, acetate (ACE), and a complex waste, cattle manure (CM). To this purpose, single chamber MECs were operated with an applied voltage of 0.7 V on a fed-batch mode. Upon biofilm formation on the sole carbon source (ACE or CM), a selected number of MECs (ACE_CM and CM_ACE) were subjected to cross-feeding during the test period. Even though the difference in the current production rate between the ACE_CM and CM_CM reactors was 20% in favour of the ACE_CM, cross-feeding lowered methane production. The results showed that there was around 20% higher methane production rate (131.6 ± 2 mL/L-d) when CM was used as the sole feed. Evidently, microbial community analysis showed that the primary substrate shapes the community of the bioelectrodes and cross-feeding does not have a significant impact on the microbial community. Based on this knowledge, the second set of experiments was designed to investigate the impact of the use of biofilm attached electrodes formed via CM addition, and the amendment of a carbon-based conductive material, granular activated carbon (GAC), on the integrated system of anaerobic digestion – microbial electrolysis cell (AD-MEC). AD-MEC systems are a combination of MECs and conventional AD reactors and have recently been used for enhanced methane production from waste materials, however, there is limited information on the start-up procedures. Further, the choice of reactor medium (buffer) is significant in the performance of bioelectrochemical systems; therefore, in this work, the performance of AD-MEC reactors fed with CM using two different buffer solutions, 100 mM phosphate-buffered saline (PBS) solution and a salt media without phosphate has been compared. Using the salt buffer solution in the AD reactor resulted in a 4 times higher net methane yield and 5.8 times lower lag time than the same reactor with 100 mM PBS media. The highest methane production rate of 12.03±0.01 mL/d and methane yield of 318.1±1.4 mLCH4/g volatile solids added (VSadded) were attained in the presence of salt medium with the amendment of biofilm-attached GAC, named, BioGAC when bare electrodes were used in AD-MEC. The yield attained in AD-MECs was around 25% higher than conventional AD.


Start-up strategies of electromethanogenic reactors for methane production from cattle manure
Ghaderikia, Amin; Taşkın, Bilgin; Yılmazel Tokel, Yasemin Dilşad (2023-03-15)
This study qualitatively assessed the impacts of different start-up strategies on the performance of methane (CH4) production from cattle manure (CM) in electromethanogenic reactors. Single chamber MECs were operated with an applied voltage of 0.7 V and the impact of electrode acclimatization with a simple substrate, acetate (ACE) vs a complex waste, CM, was compared. Upon biofilm formation on the sole carbon source (ACE or CM), several MECs (ACE_CM and CM_ACE) were subjected to cross-feeding (switching sub...
Novel investigation of pyrolysis mechanisms and kinetics for functional groups in biomass matrix
Liu, Ruijia; Liu, Guijian; Yousaf, Balal; Niu, Zhiyuan; Abbas, Qumber (2022-01-01)
Biomass, as a renewable and sustainable energy resource, can be converted into environmentally friendly and practically valuable biofuels and chemical materials via pyrolysis. However, the process optimization and pyrolysis efficiency are restricted by the limited perception of the complicated mechanisms and kinetics for biomass pyrolysis. Here, to establish an in-depth mechanism model for biomass pyrolysis, we presented a novel investigation for the thermal evolutions and pyrolysis kinetics of the function...
Numerical investigation of a stand alone solar hydrogen energy system effects of PEFC degradation
Ender, Ozden; Tarı, İlker (null; 2015-08-12)
An existing stand-alone solar energy system producing hydrogen for energy storage is numerically investigated focusing on the degradation of Polymer Electrolyte Fuel Cell (PEFC) and its effects on the overall performance of the system. The system consists of Photovoltaic (PV) panels, polymer electrolyte based electrolyzers, H2 and O2 storage tanks and a commercial PEFC stack. A PEFC is numerically investigated both as new and as degraded (for about two years). Using a variety of observed degradation pattern...
Investigation Of Influencing Factors For Biological Hydrogen Production By R. Capsulatus In Tubular Photo-Bioreactors
Boran, E.; Ozgur, E.; Gebicki, J.; van der Burg, J.; YÜCEL, MUSTAFA; Gündüz, Ufuk; Modigel, M.; Eroglu, I. (2009-05-13)
Biological hydrogen production processes are considered as an environmentally friendly way to produce hydrogen. They offer the chance to produce hydrogen from renewable energy sources, like sunlight and biomass. This study aims the process development for a photo-fermentative hydrogen production by photosynthetic purple-non-sulfur bacteria, Rhodobacter capsulatus, in a large scale (80L) tubular photo-bioreactor, in outdoor conditions, using acetate as carbon source. It was shown that Rhodobacter capsulatus ...
Experimental and numerical modeling of direct injection of CO 2 into carbonate formations
Izgec, O.; Demiral, B.; Bertin, H.; Akın, Serhat (Society of Petroleum Engineers (SPE); 2006-11-20)
Sequestration of carbon dioxide in geological formations is an alternative way to manage the carbon emitted by combustion of fossil fuels. Results of an experimental and numerical modeling study aiming to investigate the important aspects of injection of CO2 in carbonate formations are presented. Different from sandstones, in carbonates surface reaction rates are very high, so mass transfer often limits the overall reaction rate, leading to highly non-uniform dissolution patterns. Often, large flow channels...
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