Comparative Study of Electrical Conductivity on Activated Carbons Prepared from Various Cellulose Materials

Adinaveen, T.; Vijaya, J. Judith; Kennedy, L. John

doi:10.1007/s13369-014-1516-6

Cited by 65 publications

(22 citation statements)

References 40 publications

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“…The electrical resistivity of carbonaceous reducing agents decreased with increasing heat treatment temperature [8,22,27,28,32,35], increasing bulk density and increasing load. At temperatures less 950 • C, high oxygen content and disordered carbon structure act as an insulator in biomass, charcoal, and coal [3,44,45,47].…”

Section: Discussionmentioning

confidence: 99%

“…Thus, only limited amounts of generated particles fill the void fraction of bulk material. Otherwise, increasing compaction force improves the contact between neighboring particles by increasing the number of contact points [22,32] and decreasing the air gap between particles [28]. Contact resistance can be two to ten times larger than electrical resistance from solid material [22,32,34], in which a decreasing particle size results in an increasing electrical resistivity.…”

Section: Electrical Resistivity Under Loadmentioning

confidence: 99%

“…The main parameters that influence the electrical resistivity of carbon bed material are heat treatment temperature [3,5,27,28], compression pressure [3,[28][29][30][31], particle size [32][33][34], and volume fraction of the carbonaceous material [27,34]. Previous studies focused on the measurement of the electrical resistivity of powder materials [28], dry coke beds [19,22,32,35], or coke metal-oxide blends [27] of fossil fuels, whereas knowledge on the charcoal beds is limited.…”

Section: Introductionmentioning

confidence: 99%

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Electrical Resistivity of Carbonaceous Bed Material at High Temperature

et al. 2020

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This study reports the effect of high-temperature treatment on the electrical properties of charcoal, coal, and coke. The electrical resistivity of industrial charcoal samples used as a reducing agent in electric arc furnaces was investigated as a renewable carbon source. A set-up to measure the electrical resistivity of bulk material at heat treatment temperatures up to 1700 ∘C was developed. Results were also evaluated at room temperature by a four-point probe set-up with adjustable load. It is shown that the electrical resistivity of charcoal decreases with increasing heat treatment temperature and approaches the resistivity of fossil carbon materials at temperatures greater than 1400 ∘C. The heat treatment temperature of carbon material is the main influencing parameter, whereas the measurement temperature and residence time showed only a minor effect on electrical resistivity. Bulk density of the carbon material and load on the burden have a large impact on the electrical resistivity of each material, while the effect of particle size can be neglected at high heat treatment temperature or compacting pressure. The mechanical durability of charcoal slightly increased after heat treatment and decreased for coal and semi-coke samples. The results indicate that charcoal can be used as an efficient carbon source for electric arc furnaces.

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Section: Discussionmentioning

confidence: 99%

Section: Electrical Resistivity Under Loadmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrical Resistivity of Carbonaceous Bed Material at High Temperature

et al. 2020

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“…This is confirmed by the low H/C ratio stated in Section 3.1. Additionally, the oxygen content, indicating inter alia the amount of oxygen-containing surface groups, decreased remarkably, which favours the increase of EC due to the elimination of insulating effects caused by the functional groups on the surface [76].…”

Section: Discussionmentioning

confidence: 99%

Conductive Carbon Materials from the Hydrothermal Carbonization of Vineyard Residues for the Application in Electrochemical Double-Layer Capacitors (EDLCs) and Direct Carbon Fuel Cells (DCFCs)

et al. 2019

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This study investigates the production of bio-based carbon materials for energy storage and conversion devices based on two different vineyard residues (pruning, pomace) and cellulose as a model biomass. Three different char categories were produced via pyrolysis at 900 °C for 2 h (biochars, BC), hydrothermal carbonization (HTC) (at 220, 240 or 260 °C) with different reaction times (60, 120 or 300 min) (hydrochars, HC), or HTC plus pyrolysis (pyrolyzed hydrochars, PHC). Physicochemical, structural, and electrical properties of the chars were assessed by elemental and proximate analysis, gas adsorption surface analysis with N2 and CO2, compression ratio, bulk density, and electrical conductivity (EC) measurements. Thermogravimetric analysis allowed conclusions to be made about the thermochemical conversion processes. Taking into consideration the required material properties for the application in electrochemical double-layer capacitors (EDLC) or in a direct carbon fuel cell (DCFC), the suitability of the obtained materials for each application is discussed. Promising materials with surface areas up to 711 m2 g−1 and presence of microporosity have been produced. It is shown that HTC plus pyrolysis from cellulose and pruning leads to better properties regarding aromatic carbon structures, carbon content (>90 wt.%), EC (up to 179 S m−1), and porosity compared to one-step treatments, resulting in suitable materials for an EDLC application. The one-step pyrolysis process and the resulting chars with lower carbon contents and low EC values between 51 and 56 S m−1 are preferred for DCFC applications. To conclude, biomass potentials can be exploited by producing tailored biomass-derived carbon materials via different carbonization processes for a wide range of applications in the field of energy storage and conversion.

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“…However, the e-BACs matrix displays a comparable or lower resistivity, and hence a higher conductivity, as compared to other biochar-based materials, reported in the literature. For instance, resistivity was around 5.15×10 −3  m for activated carbon [54], 0.98  m for rice straw treated at 800 °C [55]. Double layer charging currents were then recorded within the scan rates range between 0.2 mV s -1 and 5 mV s -1 .…”

Section: Graphitization Degree and Electrical Conductivitymentioning

confidence: 99%

Air-breathing bio-cathodes based on electro-active biochar from pyrolysis of Giant Cane stalks

Marzorati

Goglio

Fest-Santini

et al. 2019

International Journal of Hydrogen Energy

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An innovative low-tech solution to fabricate electro-active biochar (e-biochar) electrodes for bioelectrochemical systems (BES) is proposed. Ligno-cellulosic stalks of Giant Cane (Arundo Donax L.) were subjected to pyrolysis treatment at 900 °C for 1 h. The material kept its original hollow cylindrical shape, rigid morphology and porous texture, as confirmed by 3DX-ray micro-computed tomography. These characteristics are suitable for its use at the air-water interface in BES, as air-breathing bio-cathodes. BET (Brunauer-Emmett-Teller) specific surface area was equal to 114 ± 4 m 2 g-1 , with more than 95% of pores in the microporosity range (pore diameter < 1 nm). Surface electrocatalytic activity was sufficient to sustain oxygen reduction reaction at pH 7, in terms of both onset potential (-0.02 V vs Ag/AgCl) and reduction limiting current density (1 A m-2). Electrical resistivity measurements confirmed sufficient conductivity (8.9×10 −3 ± 1×10 −4  m) of the material and Raman spectroscopy allowed to estimate a graphitization degree in relation to the ID/IG, equal to 2.26. In parallel, the e-biochar were tested as airexposed bio-cathodes in BES, coupled to carbon cloth bio-anodes. After inoculation with wastewater from swine-farming, current densities were generated in the range of 100-150 mA m-2 , along more than 2 2 months of operation, under sodium acetate feeding. Confocal laser scanning imaging revealed consistent biofilm formation on the water-side surface of the cathodes, while a nearly-complete absence of it at the air-side. These e-biochar electrodes might open innovative perspectives to scale-up BES for different applications. Here, consistent salts depositions on the material after 70 days of exposure to the wastewater, suggest that e-biochar biocathodes might serve to recycle nutrients to agricultural soils, through mineralsenriched biochar. 1. INTRODUCTION Real scale application of bio-electrochemical systems (BES) has been facing the need to find an optimal balance between processes efficiencies and costs. Many researches are addressing to develop low-cost and environmentally-compatible materials to fabricate electrodes for large scale applications, such as wastewater treatment, soil bioremediation, etc. [1-3]. To date, the most competitive materials are based on carbon and include graphite-based rods, fiber brushes and granules, carbon-fiber cloths, carbon paper sheets, carbon felt and reticulated vitreous carbon [1,2,4]. They are selected due to their strong biocompatibility and inert properties at room temperature. The use of such materials as air-breathing cathodes has been coupled to the fabrication of microporous layers, made of activated carbon, pressed on carbon cloths (or other current collector) in the presence of polymeric binders (Nafion, PTFE, etc.) [5,6]. High surface area favors the cathodic oxygen reduction reaction (ORR) that needs the simultaneous presence of solid, liquid and gaseous phases. Microporous layers also act as gas diffusion layer at air-water interface, because the p...

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Comparative Study of Electrical Conductivity on Activated Carbons Prepared from Various Cellulose Materials

Cited by 65 publications

References 40 publications

Electrical Resistivity of Carbonaceous Bed Material at High Temperature

Electrical Resistivity of Carbonaceous Bed Material at High Temperature

Conductive Carbon Materials from the Hydrothermal Carbonization of Vineyard Residues for the Application in Electrochemical Double-Layer Capacitors (EDLCs) and Direct Carbon Fuel Cells (DCFCs)

Air-breathing bio-cathodes based on electro-active biochar from pyrolysis of Giant Cane stalks

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