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.

scholarly journals ADSORPTION OF 4-CHLORPHENOL BY BROWN COAL ACTIVATED BY POTASSIUM HYDROXIDE

2021 ◽  
Vol 29 (1) ◽  
pp. 36-48
Author(s):  
Yuliia Tamarkina ◽  
Volodymyr Kucherenko ◽  
Iryna Frolova
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Brown Coal ◽  
Activated Carbons ◽  
Linear Equations ◽  
Specific Capacity ◽  
Total Pore Volume ◽  
Koh Activation ◽  
Activation Temperature ◽  
Alkaline Activation

The purpose of work is to evaluate the 4-chlorophenol (CP) adsorption capacity of brown coal activated carbons (ACs) prepared at different temperature of KOH activation. ACs were obtained in three stages: 1) impregnation of coal with a KOH solution, 2) heating (4 deg/min) in argon to a given temperature t (400-800°C) and exposure for 1 h, 3) cooling, washing from KOH, drying. The samples are designated as AC(t). Based on the N2 adsorption-desorption isotherms, the ACs total pore volume (Vt, cm3/g) and specific surface area (S, m2/g) were determined. The ACs adsorption capacity were measured at 25°С, CP concentration ≤700 mg/L, АC dosage – 1 g/L. The alkaline activation temperature was found to be a key factor in forming porosity of ACs and ability to adsorb CP. The CP maximum capacity (ACP(m), mg/g) increases 6.6 times up to 307 mg/g for AC(800) having S=1142 m2/g. The specific adsorption capacity (ACP(S) = ACP(m)/S, mg/m2) sharply decreases in a sample range from AC(400) to AC(550) and weakly depends on temperature at 550-800°C. The kinetics of CP adsorption is best described by a pseudo-second order model. The rate determining stage is the interaction of CP molecules with AC surface. The CP adsorption isotherms are best described by the Langmuir model. The dependence of the ACP(m) from S can be approximated by three linear equations that probably correspond to the three regions of forming surface adsorbtion centers (AdCs). The first (S≤370 m2/g) is characterized by a small adsorption capacity increment (kS=0.103 mg/m2), but a significant (16.4 times) decrease in the specific capacity ACP(S). In the second region (S=370-770 m2/g, t=550-750°C), capacity increment is 10 times more (kS=0.985 mg/m2) and in the third region (S≥770 m2/g, t≥750°C) the increase in CP capacity is the smallest (kS=0.067 mg/m2). The thermoinitiated formation of AdCs is assumed to be not proportional to the increase in surface area, and their chemical structure and reactivity is determined by the alkaline activation temperature.

Optimization of Production Conditions for Activated Carbons from Rice Husk by Potassium Carbonate Using Response Surface Methodology

2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Rice Husk ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Activation Temperature ◽  
Nitrogen Adsorption Isotherm

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).

Preparation of activated carbons from wet activated sludge by direct chemical activation

2009 ◽  
Vol 59 (12) ◽  
pp. 2387-2394 ◽  
Author(s):  
X. Wang ◽  
N. Zhu ◽  
J. Xu ◽  
B. Yin
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Water Content ◽  
Iodine Value ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Total Pore Volume ◽  
Processing Parameters ◽  
Experimental Conditions ◽  
Activation Temperature

An improved method for preparing activated carbons from wet waste activated sludge (WAS) by direct chemical activation was studied in this paper. The effects of processing parameters on iodine adsorption capacity of the product were investigated. Results show that sludge-based activated carbon prepared with KOH had a larger iodine value than those activated with ZnCl2 and KCl. The maximum iodine value was observed at the KOH concentration of 0.50 M. Increasing the impregnation time from 10 to 20 h resulted in a 20% increase in the iodine value. The highest iodine value was obtained at the activation temperature of 600°C and holding time of 1 h. Sludge water content had insignificant effects on the iodine value of products. Raw WAS with a water content of 93.2% can be converted into an activated carbon with a high specific surface area of 737.6 m2 g−1 and iodine value of 864.8 mgg−1 under optimum experimental conditions. Other physical properties such as total pore volume, micropore volume and mean pore diameter of the product were also reported and compared with those of commercial activated carbon.

Preparation and Characterization of Activated Carbon from Reedy Grass Leaves by Chemical Activation with KOH

2014 ◽  
Vol 881-883 ◽  
pp. 579-583 ◽  
Author(s):  
Ling Zhi Chen ◽  
Dong Xu Miao ◽  
Xiao Jie Feng ◽  
Jian Zhong Xu
Keyword(s):  
Iodine Number ◽  
Surface Area ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Weight Ratio ◽  
Raw Material ◽  
Bet Surface Area ◽  
Activation Temperature ◽  
Impregnation Ratio ◽  
Dta Analysis

Activated carbons (AC) were produced by chemical activation with potassium hydroxide (KOH) at 800°C from chars that were carbonized from reedy grass leaves at 450°C in N2atmosphere. The effects of the weight ratio of KOH/char ( impregnation ratio), activation temperature and duration time were examined. Adsorption capacity was demonstrated with iodine number. BET surface area, pore volume and pore size of activated carbons were characterized by N2adsorption isotherms. The maximum surface area and iodine number of the AC was 1100 m2/g and 1080 mg/g produced at 800°C for2h and impregnation ratio is 4:1.The characteristics of activated carbons were determined by Infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Thermal gravimetry (TG/DTA) analysis of raw material was carried out.

scholarly journals Molybdenum disulfide / mesoporous carbon nanocomposite as electrode material for supercapasitors

Energetika ◽  
2016 ◽  
Vol 61 (3-4) ◽  
Author(s):  
Lyudmyla Shyyko ◽  
Volodymyr Kotsyubynsky ◽  
Ivan Budzulyak ◽  
Bogdan Rachiy
Keyword(s):  
Electrode Material ◽  
Mesoporous Carbon ◽  
Specific Capacity ◽  
Synergetic Effect ◽  
Internal Resistance ◽  
Raw Material ◽  
Electrochemical Characteristics ◽  
Molybdenum Disulphide ◽  
Hybrid Supercapacitors ◽  
Carbon Nanocomposite

The article describes the features of MoS2/mesoporous carbon nanocomposite creation and application as an electrode material for hybrid supercapacitors. The combination of these two materials improved the electrochemical characteristics in comparison with molybdenum disulphide or mesoporous carbon on their own; in particular the synergetic effect between them led to the reduction of internal resistance and increase of electric conductivity that are reflected in the maximum power of the capacitor. In spite of a large surface area of the mesoporous carbon obtained from the raw material of plant origin (2200 m2 g–1), the synthesized nanocomposite (430 m2 g–1) has almost twice higher specific capacity (57 Fg–1 and 110 Fg–1, respectively) due to the summary effect of EDL and faradaic processes in the material. The samples were characterized by X-ray difractometry (XRD), transmission electron microscopy (TEM), porosimetry, impedance spectroscopy, voltammetry, and chronopotentiometry.

Water Treatment by Means of Activated Carbon, Prepared from Locally Available Waste Materials (II)

1986 ◽  
Vol 18 (1) ◽  
pp. 55-66 ◽  
Author(s):  
H. Keirsse ◽  
F. Van Hoof ◽  
J. Janssens ◽  
A. Buekens
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Raw Material ◽  
Environmental Standards ◽  
Activation Temperature ◽  
Treatment Processes ◽  
Waste Tyres ◽  
As Adsorption ◽  
Expensive Process ◽  
Phenol Index

Man's natural water supplies are threatened by a large number of nonbiodegradable and toxic organic compounds. Proper environmental standards often can only be attained using tertiary treatment processes, such as adsorption on activated carbon. The latter is an expensive process, owing to the initial cost of activated carbon and the losses occurring during regeneration. Methods are being investigated at the Free University of Brussels for producing and activating carbon, using various types of waste as a raw material. Following materials have already been used : cacao hulls, sawdust, fruit stones, bark, and waste tyres. Both carbonization and activation have been conducted under the carefully controlled conditions of a fluidized bed reactor. The influence of the following process parameters has been investigated : pyrolysis temperature and time, activation temperature and time, and composition of the furnace atmosphere. The resulting activated carbons should exhibit the following qualities : high adsorption capacity and rate, good resistance to attrition, and possibility of regenerating the carbon. The properties of the carbon obtained have been evaluated by means of a number of standard tests (Iodine-index, BET-surface, Tannin-index, Methylene blue-index, and Phenol-index), and adsorption isotherms of phenol, pentachlorophenol, p. toluene sulphonate and dodecyl benzenesulphonate. In general the properties of the carbons obtained were comparable to those of commercial qualities. Some of the activated carbons tested will soon be evaluated using synthetic and real phenolic industrial wastewaters (1.5 % of phenol).

scholarly journals Review on Activated Carbons by Chemical Activation with FeCl3

2020 ◽  
Vol 6 (2) ◽  
pp. 21 ◽  
Author(s):  
Jorge Bedia ◽  
Manuel Peñas-Garzón ◽  
Almudena Gómez-Avilés ◽  
Juan J. Rodriguez ◽  
Carolina Belver
Keyword(s):  
Activated Carbons ◽  
Surface Acidity ◽  
Chemical Activation ◽  
Activation Mechanism ◽  
Carbon Precursor ◽  
Iron Species ◽  
Activation Temperature ◽  
Synthesis Conditions ◽  
Porous Texture ◽  
Graphitization Degree

This study reviews the most relevant results on the synthesis, characterization, and applications of activated carbons obtained by novel chemical activation with FeCl3. The text includes a description of the activation mechanism, which compromises three different stages: (1) intense de-polymerization of the carbon precursor (up to 300 °C), (2) devolatilization and formation of the inner porosity (between 300 and 700 °C), and (3) dehydrogenation of the fixed carbon structure (>700 °C). Among the different synthesis conditions, the activation temperature, and, to a lesser extent, the impregnation ratio (i.e., mass ratio of FeCl3 to carbon precursor), are the most relevant parameters controlling the final properties of the resulting activated carbons. The characteristics of the carbons in terms of porosity, surface chemistry, and magnetic properties are analyzed in detail. These carbons showed a well-developed porous texture mainly in the micropore size range, an acidic surface with an abundance of oxygen surface groups, and a superparamagnetic character due to the presence of well-distributed iron species. These properties convert these carbons into promising candidates for different applications. They are widely analyzed as adsorbents in aqueous phase applications due to their porosity, surface acidity, and ease of separation. The presence of stable and well-distributed iron species on the carbons’ surface makes them promising catalysts for different applications. Finally, the presence of iron compounds has been shown to improve the graphitization degree and conductivity of the carbons; these are consequently being analyzed in energy storage applications.

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.

Characterization of Rambutan Seed (Nephelium lappaceum) as Natural Adsorbent for Wastewater Treatment

2013 ◽  
Vol 701 ◽  
pp. 408-411
Author(s):  
Norlia Mohamad Ibrahim ◽  
Siti Fatimah Zahra Mohd Sarif ◽  
Roshazita Che Amat ◽  
Shamshinar Salehuddin ◽  
Nur Liza Rahim
Keyword(s):  
Zinc Chloride ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Carbonization Temperature ◽  
Bet Surface Area ◽  
Nitrogen Gas ◽  
Activation Temperature ◽  
Nephelium Lappaceum ◽  
Two Factors

Activated carbons were prepared from rambutan seed with impregnation of zinc chloride as dehydrating agent. In order to find its characteristics, different zinc chloride to rambutan seed ratio (0.5 and 2) and activation temperature (450 and 650 °C) was employed. The carbonization occurred in a tube furnace with flow of nitrogen gas at 0.5 L/min. The results showed that at higher impregnation ratio and carbonization temperature produced a wider BET surface area of activated carbon that was 9.8761 m2/g. Total pore volume also increased with increases of these two factors. However activation yield was decreased with increasing of carbonization temperature.

scholarly journals OBTAINING QUALITATIVE SORBENT FROM RICE WASTE AND OIL SLUDGE

Neft i gaz ◽  
2020 ◽  
Vol 3-4 (117-1118) ◽  
pp. 169-179
Author(s):  
N.O. APPAZOV¹, ◽  
◽  
B.M. BAZARBAYEV¹, ◽  
N.I. AKYLBEKOV¹*, ◽  
R.U. ZHAPPARBERGENOV¹, ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Rice Straw ◽  
Rice Husk ◽  
Water Mass ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Carbonization Temperature ◽  
Raw Material ◽  
Oil Sludge ◽  
Adsorption Activity

Co-thermolysis of rice husk and straw with oil sludge was carried out in order to obtain a widely used adsorbent – activated carbon. Carbonization was carried out in a tubular furnace made of stainless steel at a temperature of 500°C and the activation of carbonization was carried out with water vapor at a temperature of 800°C. The influence of the ratio of the initial components of the raw material (husk / straw:oil sludge) on the properties of the product was studied. The ЭКОЛОГИЯ 172 НЕФТЬ И ГАЗ 2020. 3–4 (117–118) optimal ratio for co-thermolysis of the husk: oil sludge is 9:1 (by weight), respectively. The optimal condition for the production of activated carbon by co-thermolysis of rice straw and oil sludge is a carbonization temperature of 500°C with a duration of 100 min, activation of the carbonizate at a temperature of 850°C and with a ratio of water:carbonizate = 2:1. Indices such as iodine adsorption activity, total pore volume in water, mass fraction of moisture, and bulk density were studied. The microstructures of the obtained activated carbons were studied on a scanning scanning electron microscope. Activated carbon obtained by the joint processing of rice husk and oil sludge in a ratio of 9:1 corresponds to activated carbon brand DAK. The resulting product based on rice straw and oil sludge corresponds to the activated carbons BAU-MF, BAU-A and BAU-Ats.

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