Sustainable technologies for energy production and storage are currently in great demand. Bioelectrochemical systems (BESs) offer promising solutions for both. Several attempts have been made to improve carbon felt electrode characteristics with various pretreatments in order to enhance performance. This study was motivated by gaps in current knowledge of the impact of pretreatments on the enrichment and microbial composition of bioelectrochemical systems. Therefore, electrodes were treated with poly(neutral red), chitosan, or isopropanol in a first step and then fixed in microbial electrolysis cells (MECs). Four MECs consisting of organic substance-degrading bioanodes and methane-producing biocathodes were set up and operated in batch mode by controlling the bioanode at 400 mV vs. Ag/AgCl (3M NaCl). After 1 month of operation, Enterococcus species were dominant microorganisms attached to all bioanodes and independent of electrode pretreatment. However, electrode pretreatments led to a decrease in microbial diversity and the enrichment of specific electroactive genera, according to the type of modification used. The MEC containing isopropanol-treated electrodes achieved the highest performance due to presence of both Enterococcus and Geobacter. The obtained results might help to select suitable electrode pretreatments and support growth conditions for desired electroactive microorganisms, whereby performance of BESs and related applications, such as BES-based biosensors, could be enhanced.
- Klíčová slova
- bioelectrochemical system, bioelectrodes, biosensor, electrode pretreatment, metagenomic analysis, microbial communities,
- MeSH
- biofilmy * MeSH
- elektrody * MeSH
- elektrolýza MeSH
- Geobacter MeSH
- karbonové vlákno * MeSH
- uhlík MeSH
- zdroje bioelektrické energie * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- karbonové vlákno * MeSH
- uhlík MeSH
The Department of Defense has developed new explosive formulations in which traditionally used cyclic nitramines such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) have been updated with the insensitive munition (IM) 2,4-dinitroanisole (DNAN). Understanding combined degradation of both compounds at explosive-contaminated sites will allow remediation approaches that simultaneously target both contaminants. DNAN reduction in the presence of RDX was evaluated in abiotic experiments using substoichiometric, stoichiometric, and superstoichiometric concentrations of ferrous iron and anthrahydroquinone disulfonate within a pH range from 7.0 to 9.0. Biological degradation was investigated in resting cell suspensions of Geobacter metallireducens strain GS-15, a model Fe(III)-reducing Bacteria. Cells were amended into anoxic tubes buffered at pH 7.0, with initial 100 μM DNAN and 40-50 μM RDX. In both abiotic and biological experiments, the DNAN was reduced through the intermediate 2-methoxy-5-nitroaniline or 4-methoxy-3-nitroaniline to 2,4-diaminoanisole. In biological experiments, the RDX was reduced to form methylenedinitramine, formaldehyde (HCHO), and ammonium (NH4+). Cells were able to reduce both DNAN and RDX most readily in the presence of extracellular electron shuttles and/or Fe(III). DNAN degradation (abiotic and biotic) was faster than degradation of RDX, suggesting that the reduction of IMs will not be inhibited by cyclic nitramines, but degradation dynamics did change in mixtures when compared to singular compounds.
- MeSH
- anisoly MeSH
- Geobacter MeSH
- triaziny * MeSH
- železité sloučeniny * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Spojené státy americké MeSH
- Názvy látek
- 2,4-dinitroanisole MeSH Prohlížeč
- anisoly MeSH
- cyclonite MeSH Prohlížeč
- triaziny * MeSH
- železité sloučeniny * MeSH
In this work, two commercialized anion-exchange membranes (AEMs), AMI-7001 and AF49R27, were applied in microbial electrolysis cells (MECs) and compared with a novel AEM (PSEBS CM DBC, functionalized with 1,4-diazabicyclo[2.2.2]octane) to produce biohydrogen. The evaluation regarding the effect of using different AEMs was carried out using simple (acetate) and complex (mixture of acetate, butyrate and propionate to mimic dark fermentation effluent) substrates. The MECs equipped with various AEMs were assessed based on their electrochemical efficiencies, H2 generation capacities and the composition of anodic biofilm communities. pH imbalances, ionic losses and cathodic overpotentials were taken into consideration together with changes to substantial AEM properties (particularly ion-exchange capacity, ionic conductivity, area- and specific resistances) before and after AEMs were applied in the process to describe their potential impact on the behavior of MECs. It was concluded that the MECs which employed the PSEBS CM DBC membrane provided the highest H2 yield and lowest internal losses compared to the two other separators. Therefore, it has the potential to improve MECs.
- Klíčová slova
- Anion-exchange membrane, Biohydrogen, Internal losses, Microbial community analysis, Microbial electrolysis cell, Volatile fatty acids,
- MeSH
- anionty chemie MeSH
- design vybavení MeSH
- elektrolýza MeSH
- Geobacter metabolismus MeSH
- kvartérní amoniové sloučeniny chemie MeSH
- membrány umělé * MeSH
- piperaziny chemie MeSH
- studie proveditelnosti MeSH
- vodík metabolismus MeSH
- zdroje bioelektrické energie * mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- anionty MeSH
- kvartérní amoniové sloučeniny MeSH
- membrány umělé * MeSH
- piperaziny MeSH
- triethylenediamine MeSH Prohlížeč
- vodík MeSH
In this study, microbial fuel cells (MFCs) - operated with novel cation- and anion-exchange membranes, in particular AN-VPA 60 (CEM) and PSEBS DABCO (AEM) - were assessed comparatively with Nafion proton exchange membrane (PEM). The process characterization involved versatile electrochemical (polarization, electrochemical impedance spectroscopy - EIS, cyclic voltammetry - CV) and biological (microbial structure analysis) methods in order to reveal the influence of membrane-type during start-up. In fact, the use of AEM led to 2-5 times higher energy yields than CEM and PEM and the lowest MFC internal resistance (148 ± 17 Ω) by the end of start-up. Regardless of the membrane-type, Geobacter was dominantly enriched on all anodes. Besides, CV and EIS measurements implied higher anode surface coverage of redox compounds for MFCs and lower membrane resistance with AEM, respectively. As a result, AEM based on PSEBS DABCO could be found as a promising material to substitute Nafion.
- Klíčová slova
- Bioelectrochemical system, Membrane, Microbial community structure, Microbial fuel cell, Principal component analysis, Separator,
- MeSH
- elektrochemické techniky * přístrojové vybavení MeSH
- elektrody MeSH
- fluorokarbonové polymery MeSH
- Geobacter MeSH
- iontová výměna MeSH
- zdroje bioelektrické energie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fluorokarbonové polymery MeSH
- perfluorosulfonic acid MeSH Prohlížeč
