Electrodeposited Hybrid Biocathode-Based CO2 Reduction via Microbial Electro-Catalysis to Biofuels

Microbial electrosynthesis is a new approach to converting C1 carbon (CO2) to more complex carbon-based products. In the present study, CO2, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO2 sequestration.

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Semiquantitative Detection of Hydrogen-Associated or Hydrogen-Free Electron Transfer within Methanogenic Biofilm of Microbial Electrosynthesis

Applied and Environmental Microbiology ◽

10.1128/aem.01056-20 ◽

2020 ◽

Vol 86 (17) ◽

Cited By ~ 3

Author(s):

Weiwei Cai ◽

Wenzong Liu ◽

Bo Wang ◽

Hong Yao ◽

Awoke Guadie ◽

...

Keyword(s):

Electron Transfer ◽

Cyclic Voltammetry ◽

Value Added ◽

Combination Method ◽

Methane Generation ◽

Microbial Electrosynthesis ◽

Electrochemical Technology ◽

Insight Into

ABSTRACT Hydrogen-entangled electron transfer has been verified as an important extracellular pathway of sharing reducing equivalents to regulate biofilm activities within a diversely anaerobic environment, especially in microbial electrosynthesis systems. However, with a lack of useful methods for in situ hydrogen detection in cathodic biofilms, the role of hydrogen involvement in electron transfer is still debatable. Here, a cathodic biofilm was constructed in CH4-produced microbial electrosynthesis reactors, in which the hydrogen evolution dynamic was analyzed to confirm the presence of hydrogen-associated electron transfer near the cathode within a micrometer scale. Fluorescent in situ hybridization images indicated that a colocalized community of archaea and bacteria developed within a 58.10-μm-thick biofilm at the cathode, suggesting that the hydrogen gradient detected by the microsensor was consumed by the collaboration of bacteria and archaea. Coupling of a microsensor and cyclic voltammetry test further provided semiquantitative results of the hydrogen-associated contribution to methane generation (around 21.20% ± 1.57% at a potential of −0.5 V to −0.69 V). This finding provides deep insight into the mechanism of electron transfer in biofilm on conductive materials. IMPORTANCE Electron transfer from an electrode to biofilm is of great interest to the fields of microbial electrochemical technology, bioremediation, and methanogenesis. It has a promising potential application to boost more value-added products or pollutant degradation. Importantly, the ability of microbes to obtain electrons from electrodes and utilize them brings new insight into direct interspecies electron transfer during methanogenesis. Previous studies verified the direct pathway of electron transfer from the electrode to a pure-culture bacterium, but it was rarely reported how the methanogenic biofilm of mixed cultures shares electrons by a hydrogen-associated or hydrogen-free pathway. In the current study, a combination method of microsensor and cyclic voltammetry successfully semiquantified the role of hydrogen in electron transfer from an electrode to methanogenic biofilm.

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Increasing methane content in biogas and simultaneous value added product recovery using microbial electrosynthesis

Water Science & Technology ◽

10.2166/wst.2018.002 ◽

2018 ◽

Vol 77 (5) ◽

pp. 1293-1302 ◽

Cited By ~ 17

Author(s):

Sovik Das ◽

Pritha Chatterjee ◽

M. M. Ghangrekar

Keyword(s):

Electrode Materials ◽

Nickel Foam ◽

Phosphate Buffer Solution ◽

Value Added ◽

Product Yield ◽

Buffer Solution ◽

Hydrogen Electrode ◽

Microbial Electrosynthesis ◽

Cathodic Chamber ◽

Reduction Of Co2

Abstract Electrosynthesis of multi-carbon compounds from the carbon dioxide present in biogas is a nascent approach towards purification of biogas. Microbial electrosynthesis (MES) cells, fabricated using different electrode materials, were operated using different electrolytes and mixed anaerobic culture as biocatalysts in the cathodic chamber under an applied cathode potential of −0.7 V vs standard hydrogen electrode (SHE). The rate of production of acetate, isobutyrate, propionate and 2-piperidinone from reduction of CO2 in the cathodic chamber of the MES was 0.81 mM/day, 0.63 mM/day, 0.44 mM/day and 0.53 mM/day, respectively. As methane was also present in the biogas, methyl derivatives of these acids were also found in traces in catholyte. It was observed that the use of nickel foam as an anode, 1 M NiSO4 solution as anolyte, graphite felt as a cathode, phosphate buffer solution as catholyte at a pH of 5.2 proved to be the best possible combination for MES for this study to get enhanced product yield at higher energy efficiency.

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Electroactivity of Phototrophic River Biofilms and Constitutive Cultivable Bacteria

Applied and Environmental Microbiology ◽

10.1128/aem.00500-11 ◽

2011 ◽

Vol 77 (15) ◽

pp. 5394-5401 ◽

Cited By ~ 14

Author(s):

Emilie Lyautey ◽

Amandine Cournet ◽

Soizic Morin ◽

Stéphanie Boulêtreau ◽

Luc Etcheverry ◽

...

Keyword(s):

Stainless Steel ◽

Cyclic Voltammetry ◽

Oxygen Reduction ◽

Saturated Calomel Electrode ◽

Bacterial Strains ◽

Phenotypic Properties ◽

Content Type ◽

Population Scale ◽

River Biofilm ◽

Biofilm Development

ABSTRACTElectroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyllacontent, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from −0.36 to −0.76 V/SCE, and peak amplitudes ranging from −9.5 to −19.4 μA. These isolates were diversified phylogenetically (Actinobacteria,Firmicutes,Bacteroidetes, andAlpha-,Beta-, andGammaproteobacteria) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowingin situphototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions.

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Valorization of secondary feedstocks from the agroindustry by selective catalytic oxidation to formic and acetic acid using the OxFA process

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-01854-7 ◽

2021 ◽

Author(s):

Sebastian Ponce ◽

Stefanie Wesinger ◽

Daniela Ona ◽

Daniela Almeida Streitwieser ◽

Jakob Albert

Keyword(s):

Acetic Acid ◽

Formic Acid ◽

Reaction System ◽

Value Added ◽

Industrial Wastes ◽

Raw Material ◽

Gaseous Oxygen ◽

Water As Solvent ◽

Selective Catalytic Oxidation ◽

Major Interest

AbstractThe selective oxidative conversion of seven representative fully characterized biomasses recovered as secondary feedstocks from the agroindustry is reported. The reaction system, known as the “OxFA process,” involves a homogeneous polyoxometalate catalyst (H8PV5Mo7O40), gaseous oxygen, p-toluene sulfonic acid, and water as solvent. It took place at 20 bar and 90 °C and transformed agro-industrial wastes, such as coffee husks, cocoa husks, palm rachis, fiber and nuts, sugarcane bagasse, and rice husks into biogenic formic acid, acetic acid, and CO2 as sole products. Even though all samples were transformed; remarkably, the reaction obtains up to 64, and 55% combined yield of formic and acetic acid for coffee and cocoa husks as raw material within 24 h, respectively. In addition to the role of the catalysts and additive for promoting the reaction, the influence of biomass components (hemicellulose, cellulose and lignin) into biogenic formic acid formation has been also demonstrated. Thus, these results are of major interest for the application of novel oxidation techniques under real recovered biomass for producing value-added products. Graphical abstract

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Microstructure and Properties of 304 Stainless Steel Specimen Manufactured by Cold Metal Transfer + Pulse Composite Arc Additive

Science of Advanced Materials ◽

10.1166/sam.2021.3876 ◽

2021 ◽

Vol 13 (1) ◽

pp. 152-160

Author(s):

Yanjie Wang ◽

Xuru Hou ◽

Lin Zhao ◽

Yun Peng ◽

Chengyong Ma ◽

...

Keyword(s):

Stainless Steel ◽

Additive Manufacturing ◽

Fracture Surface ◽

Steel Specimen ◽

Corrosion Current ◽

Electrochemical Analysis ◽

304 Stainless Steel ◽

Cold Metal Transfer ◽

Σ Phase ◽

Microstructure And Properties

304 stainless steel test block was fabricated by continuous melting wire with CMT and pulse mixed mode, and the path of additive manufacturing is layered slice S-shaped. The relationship between microstructure and properties of the specimen was investigated by microscope, SEM, EBSD, XRD, tensile, impact and electrochemical experiments. The results show that molding between weld and weld is very good, and the microstructure is mainly Austenite, Ferrite and a little of σ, and there are three kinds of Ferrite morphology: cellular, wormlike and lath. σ phase precipitates easily in regions with high ferrite content and is distributed at the boundary between austenite and ferrite. The specimen has good low temperature toughness. The microscopic fracture surface is mainly dimple, and the precipitates in the fracture surface are mainly fine carbide particles. The tensile strength of the additive manufacturing 304 specimen is higher than the forged specimen, and the type of fracture is ductile fracture. The electrochemical analysis of 304 stainless steel specimens and forgings shows that CMT and pulse arc additive manufacturing specimen has excellent corrosion resistance and its corrosion current is slightly lower than the forging.

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Natural Sulfide Minerals as Electrode Materials for Electrochemical Analysis in Dipolar Aprotic Solvents

International Journal of Electrochemical Science ◽

10.20964/2018.11.74 ◽

2018 ◽

pp. 11113-11135

Author(s):

Zorka Stanić ◽

Keyword(s):

Electrode Materials ◽

Electrochemical Analysis ◽

Sulfide Minerals ◽

Aprotic Solvents ◽

Dipolar Aprotic Solvents

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Catalytic valorization of hardwood for enhanced xylose-hydrolysate recovery and cellulose enzymatic efficiency via synergistic effect of Fe3+ and acetic acid

Biotechnology for Biofuels ◽

10.1186/s13068-019-1587-4 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 4

Author(s):

Kaixuan Huang ◽

Lalitendu Das ◽

Jianming Guo ◽

Yong Xu

Keyword(s):

Acetic Acid ◽

Synergistic Effect ◽

Paper Industry ◽

Enzymatic Saccharification ◽

Value Added ◽

Lewis Acid Site ◽

Aqueous Acetic Acid ◽

Xylan Degradation ◽

Hydrolysis Process ◽

Xylonic Acid

Abstract Background Poplars are considered suitable dedicated energy crops, with abundant cellulose and hemicellulose, and huge surplus biomass potential in China. Xylan, the major hemicellulosic component, contributes to the structural stability of wood and represents a tremendous quantity of biobased chemicals for fuel production. Monomeric xylose conversion to value-added chemicals such as furfural, xylitol, and xylonic acid could greatly improve the economics of pulp-paper industry and biorefinery. Acetic acid (HAc) is used as a friendly and recyclable selective catalyst amenable to xylan degradation and xylooligosaccharides production from lignocellulosic materials. However, HAc catalyst usually works much feebly at inert woods than agricultural straws. In this study, effects of different iron species in HAc media on poplar xylan degradation were systematically compared, and a preferable Fe3+-assisted HAc hydrolysis process was proposed for comparable xylose-hydrolysate recovery (XHR) and enzymatic saccharification of cellulose. Results In presence of 6.5% HAc with 0.17–0.25 wt% Fe3+, xylose yield ranged between 72.5 and 73.9%. Additionally, pretreatment was effective in poplar delignification, with a lignin yield falling between 38.6 and 42.5%. Under similar conditions, saccharification efficiency varied between 60.3 and 65.9%. Starting with 100 g poplar biomass, a total amount of 12.7–12.8 g of xylose and 18.8–22.8 g of glucose were harvested from liquid streams during the whole process of Fe3+-HAc hydrolysis coupled with enzymatic saccharification. Furthermore, the enhancement mechanism of Fe3+ coupled with HAc was investigated after proof-of-concept experiments. Beechwood xylan and xylose were treated under the same condition as poplar sawdust fractionation, giving understanding of the effect of catalysts on the hydrolysis pathway from wood xylan to xylose and furfural by Fe3+-HAc. Conclusions The Fe3+-assisted HAc hydrolysis process was demonstrated as an effective approach to the wood xylose and other monosaccharides production. Synergistic effect of Lewis acid site and aqueous acetic acid provided a promising strategy for catalytic valorization of poplar biomass.

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Electrochemical analysis of water and suds by impedance spectroscopy and cyclic voltammetry

Journal of Sensors and Sensor Systems ◽

10.5194/jsss-3-133-2014 ◽

2014 ◽

Vol 3 (2) ◽

pp. 133-140 ◽

Cited By ~ 3

Author(s):

R. Gruden ◽

A. Buchholz ◽

O. Kanoun

Keyword(s):

Water Quality ◽

Cyclic Voltammetry ◽

Impedance Spectroscopy ◽

Electrochemical Analysis ◽

Total Hardness ◽

Impedance Measurements ◽

Washing Process ◽

Calcium Magnesium ◽

The Ideal

Abstract. Optimum detergent dosage during a washing process depends on water quality, degree of pollution and quantity of laundry. Particularly, water quality is an important factor. Other parameters like carbonate- or non-carbonate hardness and calcium / magnesium (Ca / Mg) ratio in addition to total hardness of water have an impact on the amount of detergent. This work discusses the possibilities realizing a detergent sensor that measures important parameters for the washing process and assess the ideal necessary amount of detergent during the washing process. The approach is to combine impedance spectroscopy with cyclic voltammetry in order to determine both water quality and concentration of detergent in the suds which build up the basis for an optimum detergent dosage. The results of cyclic voltammetry show that it is possible to identify the Ca / Mg ratio and the carbonate hardness separately, which is necessary for the optimization of the washing process. Impedance measurements identify total hardness and detergent concentrations.

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RETRACTED: The Study of Composition and Morphology of Pd-Ag Alloy Powders by Electrodeposition

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.732.81 ◽

2017 ◽

Vol 732 ◽

pp. 81-85

Author(s):

Chin Ming Chu ◽

Shi Wen Yang ◽

Shen Li Tsai ◽

Wen Bing Yang

Keyword(s):

Stainless Steel ◽

Cyclic Voltammetry ◽

Reduction Potential

Pd-Ag alloy powders were prepared on the stainless steel by DC electrodeposition. Cyclic voltammetry found the reduction potential of Pd, Ag and Pd-Ag. The composition and morphology of Pd-Ag were investigated by means of SEM, EDS.

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