Development of a novel palm fiber biofilm electrode reactor (PBER) for nitrate-contaminated wastewater treatment: performance and mechanism

2020 ◽  
Vol 6 (3) ◽  
pp. 839-850 ◽  
Author(s):  
Chen Yang ◽  
Chuanping Feng ◽  
Nan Chen ◽  
Yang Deng ◽  
Weiwu Hu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Wastewater Treatment ◽  
Electrochemical Reduction ◽  
Nitrate Reduction ◽  
Extracellular Electron Transfer ◽  
Autotrophic Denitrification ◽  
Palm Fiber ◽  
Treatment Performance ◽  
Performance And Mechanism ◽  
Heterotrophic Denitrification

The main pathways for nitrate reduction are electrochemical reduction, heterotrophic denitrification, hydrogen autotrophic denitrification and extracellular electron transfer.

Wood derived biochar as electron donor and its influence on microbial denitrification: Role of extracellular polymeric substances in extracellular electron transfer

2020 ◽  
Author(s):  
Kuppusamy Sathishkumar ◽  
Yi Li ◽  
Rana Muhammad Adnan Ikram
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Electrochemical Behavior ◽  
Nitrate Reduction ◽  
Extracellular Polymeric Substances ◽  
Electrochemical Impedance ◽  
Electrochemical Analysis ◽  
Extracellular Electron Transfer ◽  
Microbial Denitrification

<p>Biochar is extensively used in environmental pollutant remediation because of its diverse property, however the effect of biochar on microbial nitrate reduction and electrochemical behavior of biochar remain unknown. Also electron transfer from the microbial cells to electron donor or acceptor have been transport across the extracellular polymeric substances (EPS), however it was unclear whether extracellular polymeric substances captured or enhance the electrons.  Hence, aim of the present study is to investigate the electrochemical behavior of biochar and its effects on microbial nitrate reduction and elucidate the role of extracellular polymeric substances in extracellular electron transfer (EET).  The biochar was prepared at different pyrolysis temperatures (400 °C, 500 °C and 600 °C) and their electrochemical behavior was characterized by electrochemical analysis (cyclic voltammetry, electrochemical impedance spectrum, chronoamperometry). Results demonstrated that all the biochars could donate and accept the electrons, impact of biochar on microbial nitrate reduction was studied and the results showed that biochar prepared at 400 °C significantly enhances microbial nitrate reduction process. Phenol O-H and quinone C=O surface functional groups on the biochar contributes in the overall electron exchange which accelerated the nitrate reduction. The role of EPS in EET by electrochemical analysis results reveals that outer membrane c-type cytochrome and flavin protein from the biofilm was involved in electron transfer process, and EPS act as transient media for microbial EET. Overall, present study suggested that biochar could be used as eco-friendly material for the enhancement of microbial denitrification.</p>

scholarly journals Taxonomic and functional metagenomic analysis of anodic communities in two pilot-scale microbial fuel cells treating different industrial wastewaters

2015 ◽  
Vol 12 (3) ◽  
pp. 1-15 ◽  
Author(s):  
Larisa Kiseleva ◽  
Sofya K. Garushyants ◽  
Hongwu Ma ◽  
David J.W. Simpson ◽  
Viatcheslav Fedorovich ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Wastewater Treatment ◽  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Pilot Scale ◽  
Metagenomic Analysis ◽  
Anode Surface ◽  
Extracellular Electron Transfer ◽  
Climatic Zones ◽  
Electrochemically Active

Summary The combined processes of microbial biodegradation accompanied by extracellular electron transfer make microbial fuel cells (MFCs) a promising new technology for cost-effective and sustainable wastewater treatment. Although a number of microbial species that build biofilms on the anode surfaces of operating MFCs have been identified, studies on the metagenomics of entire electrogenic communities are limited. Here we present the results of wholegenome metagenomic analysis of electrochemically active robust anodic microbial communities, and their anaerobic digester (AD) sludge inocula, from two pilot-scale MFC bioreactors fed with different distillery wastewaters operated under ambient conditions in distinct climatic zones. Taxonomic analysis showed that Proteobacteria, Bacteroidetes and Firmicutes were abundant in AD sludge from distinct climatic zones, and constituted the dominant core of the MFC microbiomes. Functional analysis revealed species involved in degradation of organic compounds commonly present in food industry wastewaters. Also, accumulation of methanogenic Archaea was observed in the electrogenic biofilms, suggesting a possibility for simultaneous electricity and biogas recovery from one integrated wastewater treatment system. Finally, we found a range of species within the anode communities possessing the capacity for extracellular electron transfer, both via direct contact and electron shuttles, and show differential distribution of bacterial groups on the carbon cloth and activated carbon granules of the anode surface. Overall, this study provides insights into structural shifts that occur in the transition from an AD sludge to an MFC microbial community and the metabolic potential of electrochemically active microbial populations with wastewater-treating MFCs.

scholarly journals RuIII(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21359-21366
Author(s):  
Debabrata Chatterjee ◽  
Marta Chrzanowska ◽  
Anna Katafias ◽  
Maria Oszajca ◽  
Rudi van Eldik
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Electrochemical Reduction ◽  
Molecular Oxygen ◽  
Outer Sphere ◽  
Transfer Processes ◽  
Edta Complexes ◽  
Inner Sphere ◽  
Electron Transfer Processes ◽  
Sphere Mechanism

[RuII(edta)(L)]2–, where edta4– =ethylenediaminetetraacetate; L = pyrazine (pz) and H2O, can reduce molecular oxygen sequentially to hydrogen peroxide and further to water by involving both outer-sphere and inner-sphere electron transfer processes.

Sign in / Sign up

Export Citation Format

Share Document