RESOURCE STABILITY OF ACTIVATED CARBON FROM WOOD IN SUPERCAPACITORS WITH ORGANIC ELECTROLYTE

1970 ◽  
Vol 61 (11) ◽  
Author(s):  
Daria E. Vervikishko ◽  
Svetlana A. Kochanova ◽  
Alexander V. Dolzhenko ◽  
Irina A. Lipatova ◽  
Evgeny I. Shkolnikov
Keyword(s):  
Activated Carbon ◽  
Functional Groups ◽  
Activated Carbons ◽  
Autonomous Systems ◽  
Great Influence ◽  
Organic Electrolyte ◽  
Electrochemical Characteristics ◽  
High Resource ◽  
Electric Capacity ◽  
A Charge

One of advantages of supercapacitors in comparison with batteries is their potentially high resource. Resource stability, as well as a supercapacitor self-discharge, depends on many factors. The most important of them are impurities in electrolyte, carbon materials and functional groups on their surface. Authors have offered perspective carbon material – the activated carbon from wood received by thermochemical synthesis. The electric capacity around 160 F/g is reached in supercapacitors with aprotic organic electrolyte (1M tetraethylammonium tetrafluoroborate). Authors have conducted the research of properties of the developed activated carbons from wood aiming to check resource opportunities supercapacitors with aprotic organic electrolyte. Resource tests lasted more than 6.5 months. Today more than one million cycles of a charge – discharge are reached at charge current of 100 mA/cm2. It is established that functional groups have a great influence on a resource of supercapacitors. To achieve high levels of stability in the resource activation technology developed carbon is provided to minimize the number of functional groups. Heat treatment of carbons after activation in the environment of argon at the increased temperatures was in addition carried out. It is shown that electrochemical characteristics of the supercapacitor throughout resource tests are at the stable level. Thus, there are bases to believe that devices on the basis of this carbon will be able to work continuously during the large period of time that is especially important, for example, for the autonomous systems located in hard-to-reach spots.

Wood-based activated carbons for supercapacitors with organic electrolyte

Holzforschung ◽  
2015 ◽  
Vol 69 (6) ◽  
pp. 777-784 ◽  
Author(s):  
Galina Dobele ◽  
Aleksandrs Volperts ◽  
Galina Telysheva ◽  
Aivars Zhurinsh ◽  
Daria Vervikishko ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Specific Capacity ◽  
Total Pore Volume ◽  
Synthesis Temperature ◽  
Raw Material ◽  
Organic Electrolyte ◽  
Electrochemical Characteristics ◽  
Activation Temperature ◽  
Synthesis Conditions ◽  
Ohmic Losses

Abstract The thermocatalytical synthesis conditions required for the activation of wood charcoal with NaOH in terms of the formation of pores in its structure were investigated. The present study was conducted to explore the potential application of activated carbons as electrodes in supercapacitors with organic electrolyte. The total pore volume and micro- and mesopore ratio were controlled by the activation temperature and alkali addition rate. The working characteristics of carbon electrodes (e.g., specific capacity and ohmic losses) in supercapacitors are strongly influenced by the properties of the pores in their structures. Herein, the optimal ratio of raw material to activator and activation temperature are established: an increase in the ratio of NaOH to carbonizate rate by a factor of 2 and setting the synthesis temperature at 700°C positively influence the electrochemical characteristics of supercapacitors and provide them with specific capacities of up to 160 F g-1.

Modification of Activated Carbon and its Application on Adsorption of UDMH Gas

2013 ◽  
Vol 634-638 ◽  
pp. 1026-1030 ◽  
Author(s):  
Huan Chun Wang ◽  
Xiao Li Gou ◽  
Xiao Meng Lv
Keyword(s):  
Activated Carbon ◽  
High Temperature ◽  
Transition Metal ◽  
Surface Structure ◽  
Functional Groups ◽  
Room Temperature ◽  
Activated Carbons ◽  
Metal Solution ◽  
Modified Activated Carbons

Two kinds of modified activated carbons were prepared by dipping with Zn(NO3)2 solution and by reducing in the atmosphere of N2 at high temperature respectively, which were characterized by FTIR,DSC,SEM and EDS. The surface structure was strongly changed in the process, along with the changes of chemical functional groups. The results of adsorption experiments revealed that the adsorbent capacities of UDMH gas at room temperature were enhanced obviously by modification compared with the raw activated carbon, especially dipped by transition metal solution. The mechanism probably involved was also discussed.

scholarly journals Adsorption of Polydisperse Polyvinyl Alcohol Molecules on the Surface of Activated Carbons

2003 ◽  
Vol 21 (5) ◽  
pp. 463-473
Author(s):  
J. Barkauskas ◽  
A. Vinslovaite
Keyword(s):  
Activated Carbon ◽  
Polyvinyl Alcohol ◽  
Functional Groups ◽  
Adsorption Process ◽  
Activated Carbons ◽  
Surface Heterogeneity ◽  
Raw Material ◽  
Carbon Substrate ◽  
Gel Chromatography ◽  
Graphene Layers

The adsorption of polyvinyl alcohol (PVA) on activated carbons was studied in aqueous solutions. Each batch of activated carbon produced was obtained via a definite number of technological operations using wood as the raw material. The adsorption process was studied using a gel chromatography technique with potentiometric titrations being employed for evaluating the chemical composition of the activated carbons produced. The data obtained from the various activated carbon samples were compared to ascertain the adsorption mechanism. It was concluded that water molecules had a limited influence on the competitive process of polymer adsorption. A rather pronounced negative correlation between the number of phenol functional groups and PVA adsorption capacity was observed, indicating that these groups hindered the adsorption process. Assumptions concerning the role of phenol functional groups were made, taking into account not only the surface heterogeneity but also changes in the electron density of the graphene layers in the carbon substrate.

scholarly journals Immersion Calorimetry for the Characterization of PD Catalysts Supported on Activated Carbon

2009 ◽  
Vol 6 (4) ◽  
pp. 1221-1227
Author(s):  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Functional Groups ◽  
Activated Carbons ◽  
The Other ◽  
Pd Catalysts ◽  
Immersion Calorimetry ◽  
Characterization Techniques ◽  
The Difference

Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2and CO2isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.

scholarly journals Role of Activated Carbon Precursor for Mercury Oxidation and Removal: Oxidized Surface and Carbene Site Interaction

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1190
Author(s):  
Regina Rodriguez ◽  
Domenic Contrino ◽  
David Mazyck
Keyword(s):  
Activated Carbon ◽  
Nitric Acid ◽  
Gas Phase ◽  
Functional Groups ◽  
Bituminous Coal ◽  
Activated Carbons ◽  
Elemental Mercury ◽  
Coconut Shell ◽  
Mercury Removal ◽  
Oxygen Functional Groups

Activated carbon (AC) is widely accepted for the removal of inorganic contaminants like mercury; however, the raw material used in the production of activated carbon is not always taken into consideration when evaluating its efficacy. Mercury oxidation and adsorption mechanisms governed by carbene sites are more likely to occur when graphitic-like activated carbons (such as those produced from high-ranking coals) are employed versus lignocellulosic-based ACs; this is likely due to the differences in carbon structures where lignocellulosic materials are less aromatic. In this research, the team studied bituminous coal-based ACs in comparison to coconut shell and wood-based (both less aromatic) ACs for elemental mercury removal. Nitric acid of 0.5 M, 1 M, and 5 M concentrations along with 10 M hydrogen peroxide were used to oxidize the surface of the ACs. Boehm titrations and FTIR analysis were used to quantify the addition of functional groups on the activated carbons. A trend was observed herein, resulting in increasing nitric acid molarity and an increased quantity of oxygen-containing functional groups. Gas-phase mercury removal mechanisms including physisorption, oxygen functional groups, and carbene sites were evaluated. The results showed significantly better elemental mercury removal in the gas phase with a bituminous coal-based AC embodying similar physical and chemical characteristics to that of its coconut shell-based counterpart. The ACs treated with various oxidizing agents to populate oxygen functional groups on the surface showed increased mercury removal. It is hypothesized that nitric acid treatment creates oxygen functional groups and carbene sites, with carbene sites being more responsible for mercury removal. Heat treatments post-oxidation with nitric acid showed remarkable results in mercury removal. This process created free carbene sites on the surface and shows that carbene sites are more reactive to mercury adsorption than oxygen. Overall, physisorption and oxygen functional groups were also dismissed as mercury removal mechanisms, leaving carbene-free sites as the most compelling mechanism.

scholarly journals Surface Modification and Characterization of Coconut Shell-Based Activated Carbon Subjected to Acidic and Alkaline Treatments

2017 ◽  
Vol 4 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Tan I. A. W. ◽  
Abdullah M. O. ◽  
Lim L. L. P. ◽  
Yeo T. H. C.
Keyword(s):  
Activated Carbon ◽  
Surface Morphology ◽  
Surface Chemistry ◽  
Pore Structure ◽  
Surface Area ◽  
Functional Groups ◽  
Activated Carbons ◽  
Coconut Shell ◽  
Bet Surface Area ◽  
Textural Characterization

Activated carbon derived from agricultural biomass has been increasingly recognized as a multifunctional material for various applications according to its physicochemical characteristics. The application of activated carbon in adsorption process mainly depends on the surface chemistry and pore structure which is greatly influenced by the treatment method. This study aims to compare the textural characteristics, surface chemistry and surface morphology of coconut shell-based activated carbon modified using chemical surface treatments with hydrochloric acid (HCl) and sodium hydroxide (NaOH). The untreated and treated activated carbons were characterized for their physical and chemical properties including the Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and textural characterization. The FTIR spectra displayed bands confirming the presence of carboxyl, hydroxyl and carbonyl functional groups. The Brunauer–Emmett–Teller (BET) surface area of the untreated activated carbon was 436 m2/g whereas the surface area of the activated carbon modified using 1M NaOH, 1M HCl and 2M HCl was 346, 525 and 372 m2/g, respectively. SEM micrographs showed that many large pores in a honeycomb shape were clearly found on the surface of 1M HCl sample. The pore structure of the activated carbon treated with 2M HCl and NaOH was partially destroyed or enlarged, which decreased the BET surface area. The modification of the coconut shell-based activated carbon with acidic and alkaline treatments has successfully altered the surface functional groups, surface morphology and textural properties of the activated carbon which could improve its adsorptive selectivity on a certain adsorbate.

scholarly journals Coffee residue-based activated carbons for phenol removal

2021 ◽  
Author(s):  
Hemavathy Palanisami ◽  
Mohamad Rafiuddin Mohd Azmi ◽  
Muhammad Abbas Ahmad Zaini ◽  
Zainul Akmar Zakaria ◽  
Muhd Nazrul Hisham Zainal Alam ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Functional Groups ◽  
High Performance ◽  
Activated Carbons ◽  
Phenol Removal ◽  
Surface Functional Groups ◽  
Maximum Capacity ◽  
Second Stage ◽  
Adsorptive Properties

Abstract This work was aimed to evaluate the adsorptive properties of activated carbons from coffee residue for phenol removal. The coffee residue was activated using H3PO4 and KOH, and the resultant activated carbons were characterized for surface area and functional groups. The values of surface area were recorded as 1,030 m2/g and 399 m2/g for H3PO4- and KOH-activated carbons, respectively. The maximum capacity for phenol removal is comparable for both activated carbons at 43 mg/g. The pores might be inaccessible due to electrostatic repulsion by surface functional groups and hydroxyl anions. The second stage in a two-stage adsorber design is necessary to accomplish the process with high performance and minimum dosage of activated carbon. Coffee residue is a promising activated carbon precursor for phenol removal.

scholarly journals Preparation and characterization of bio-based activated carbon from fish scales

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 614-621
Author(s):  
Qingsong Ji ◽  
Haichao Li ◽  
Jingjing Zhang
Keyword(s):  
Activated Carbon ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Structural Characteristics ◽  
Total Pore Volume ◽  
Bet Surface Area ◽  
Fish Scales ◽  
Average Pore ◽  
Activation Temperature

The object of this study was to prepare activated carbons containing nitrogenous functional groups by a chemical method from nitrogen-containing raw materials. Fish (Ctenopharyngodon idellus) scales were impregnated with phosphoric acid (H3PO4) and activated at varied temperatures. The adsorption ability, structural characteristics, surface chemistry, and morphology of the activated carbons were characterized by methylene blue and iodine values, nitrogen adsorption, the Boehm method, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The total alkaline groups content of the activated carbon produced from fish scales was 0.4330 mmol/g, the total acidic groups was 1.68 mmol/g, the Brunauer–Emmett–Teller (BET) surface area was 501 cm2/g, and the total pore volume was 0.284 cm3/g. The average pore diameter was 1.94 nm under an activation temperature of 550 °C, an activation time of 1 h, and an impregnation ratio of 2. As a result of this study, nitrogenous functional groups that contained acid-base amphoteric adsorbent were produced.

Electrochemical Insight into Cycle Stability of Organic Electrolyte Supercapacitors

2011 ◽  
Vol 347-353 ◽  
pp. 467-471
Author(s):  
Zheng Jia ◽  
Dao Qing Liu ◽  
Si Yuan Yang
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Organic Electrolyte ◽  
Cyclic Voltammograms ◽  
Cycle Stability ◽  
Electrode Processes ◽  
Two Factors ◽  
Circuit Component ◽  
Nyquist Plots

Two types of activated carbons were produced by chemical activation respectively with and without pre-carbonization procedure, and were used in organic electrolyte supercapacitors. Galvanostatic charge and discharge results show that voltage upper limit and activated carbon type obviously influence the cycle stability of the capacitors. And cyclic voltammograms reveal the better capacitive behavior and cycle stability of the activated carbon produced with carbonization procedure implying the correlation between these two factors. While Nyquist plots disclose the tendency of equivalent circuit component parameters and electrode processes with cycling.

Effect of Ammonia Modification on Activated Carbons for the Removal of Acidic Anthraquinone Dyes

2019 ◽  
Vol 17 (8) ◽  
Author(s):  
Hind Yaacoubi ◽  
Zuo Songlin
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Activated Carbons ◽  
Coconut Shell ◽  
Diffusion Kinetic ◽  
Anthraquinone Dyes ◽  
Adsorption Sites ◽  
Adsorption Affinity ◽  
Adsorption Rates

Abstract The objective of this research is to study the retention of two acidic anthraquinone dyes by Coconut-shell-based activated carbon. Ultimately, this work allows the valorization of this new material as an adsorbent. The effect of ammonia modification on the adsorption capacity of activated carbon towards remazol brilliant blue R19 (RB19) and acid blue 25 (AB25), has been studied. Coconut-shell-based activated carbon material was modified under ammonia flow at 900 and 1000 °C. The adsorption rates and isotherms of RB19 and AB25 on the resultant materials were then tested. The results show that ammonia modification remarkably increases the adsorption capacities of the activated carbons to RB19 and AB25, by a factor of 2–3 after treatment at 1000 °C (From 0.22 mmol g−1 and 1.04 mmol g−1 to 0.76 mmol g−1 and 2.19 mmol g−1 on AC and AC-O-N-1000, respectively). The increased adsorption capacity is attributed to the introduction of basic nitrogen-containing functional groups and enhanced pore development by ammonia modification. The collected experimental kinetic and isotherm data are well compatible with the intraparticle diffusion kinetic model and the Langmuir isotherm model. According to these results, the adsorption affinity is homogeneous in terms of surface functional groups and the surface bears a finite number of identical adsorption sites.

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