scholarly journals The effects of activation conditions on physical properties of activated carbon

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7640-7647
Author(s):  
Yan Luo ◽  
Kang Wang ◽  
Ling Fei
Keyword(s):  
Activated Carbon ◽  
Physical Properties ◽  
Surface Area ◽  
Pore Volume ◽  
Specific Volume ◽  
Activated Carbons ◽  
Weight Ratio ◽  
Total Pore Volume ◽  
High Porosity ◽  
Activation Conditions

Porous carbons with a high porosity were successfully produced from fast pyrolysis pine wood char via a thermochemical method in which KOH was used as chemical activator. The effects of various weight ratios of KOH to pyrolysis char (0.65:1, 0.7:1, 1.0:1, 1.35:1, and 1.7:1) on the physical properties of activated carbons were investigated. When the weight ratio of KOH to pyrolysis char was 1.35:1, the prepared activated carbon had the highest surface area of 1140 m2/g with a total pore volume of 0.71 cm3/g, a microporous surface area of 957 m2/g, and a microporous specific volume of 0.51 cm3/g. As the weight ratio of KOH to pyrolysis char increased from 0.65 to 1.35, the prepared activated carbon had increases in total surface area, total pore volume, microporous surface area, and specific volume of micropores. However, there was a reverse trend when the weight ratio of KOH to pyrolysis char was higher than 1.35. The use of nitrogen as a flow gas resulted in much more developed activated carbon than without nitrogen. The experiment results suggested that activated carbon with high surface area could be prepared from pyrolysis char by adjusting the activation conditions.

Preparation of Activated Carbons from Lignite for Electrochemical Capacitors by Microwave and Electrical Furnace Heating

2011 ◽  
Vol 194-196 ◽  
pp. 2472-2479 ◽  
Author(s):  
Bao Lin Xing ◽  
Chuan Xiang Zhang ◽  
Lun Jian Chen ◽  
Guang Xu Huang
Keyword(s):  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
Electrochemical Capacitors ◽  
Weight Ratio ◽  
Total Pore Volume ◽  
Electrochemical Performances

Activated carbons (ACs) were prepared from lignite by microwave (MW) and electrical furnace (EF) heating with KOH as activation agent. In order to compare pore structures and electrochemical performances of ACs prepared by both heating methods, the ACs were characterized by N2 adsorption at 77K, X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrochemical performances of Electrochemical capacitors (ECs) with ACs as electrodes in 3mol/L KOH electrolyte were evaluated by constant current charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the pore structures of ACs prepared by MW and EF heating significantly enhance when the weight ratio of KOH to coal increases from 2 to 4. The BET specific surface area, total pore volume, the ratio of mesopore and average pore diameter of ACs prepared by MW heating (denoted as AC-MW4) reaches 2094m2/g, 1.193cm3/g, 53.6%, 2.28nm when the weight ratio of KOH to coal is 4, and ACs prepared by EF heating (denoted as AC-EF4) reaches 2580m2/g, 1.683cm3/g, 67.3%, 2.61nm. The ECs with AC-MW4 and AC-EF4 as electrodes present a high specific capacitance of 348F/g and 377F/g at a current density of 50mA/g, and still remain 325F/g and 350F/g after 500 cycles, respectively. Although the specific surface area, total pore volume and specific capacitance of ACs prepared by MW heating are slightly lower than EF heating, taking into account the heating time in the activation process, ACs prepared by EF heating needs approximate 140min, while MW heating only needs 10min, which have demonstrated that microwave heating technology is a promising and efficient technique to prepare ACs.

scholarly journals Carbonization Temperature Effect over Activated Carbon Porosity Derived from Industrial Processing Waste

2019 ◽  
Vol 2 (3) ◽  
pp. 1205-1209
Author(s):  
Hasan Sayğılı
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
Waste Product ◽  
Total Pore Volume ◽  
Carbonization Temperature ◽  
Bet Surface Area ◽  
Processing Waste ◽  
Industrial Processing

The influence of carbonization temperature (CT) on pore properties of the prepared activated carbon using lentil processing waste product (LWP) impregnated with potassium carbonate was studied. Activated carbons (ACs) were obtained by impregnation with 3:1 ratio (w/w) K2CO3/LWP under different carbonization temperatures at 600, 700, 800 and 900 oC for 1h. Activation at low temperature represented that micropores were developed first and then mesoporosity developed, enhanced up to 800 oC and then started to decrease due to possible shrinking of pores. The optimum temperature for LWP was found to be around 800 oC on the basis of total pore volume and the Brunauer-Emmett-Teller (BET) surface area. The optimum LWPAC sample was found with a CT of 800 oC, which gives the highest BET surface area and pore volume of 1875 m2/g and 0.995 cm3/g, respectively.

scholarly journals Effect of Mesopore Development on Butane Working Capacity of Biomass-Derived Activated Carbon for Automobile Canister

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 673
Author(s):  
Byeong-Hoon Lee ◽  
Hye-Min Lee ◽  
Dong Chul Chung ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Volume Fraction ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Working Capacity ◽  
Activation Time

Kenaf-derived activated carbons (AKC) were prepared by H3PO4 activation for automobile canisters. The microstructural properties of AKC were observed using Raman spectra and X-ray diffraction. The textural properties were studied using N2/77 K adsorption isotherms. Butane working capacity was determined according to the ASTM D5228. From the results, the specific surface area and total pore volume of the AKC was determined to be 1260–1810 m2/g and 0.68–2.77 cm3/g, respectively. As the activation time increased, the butane activity and retentivity of the AKC increased, and were observed to be from 32.34 to 58.81% and from 3.55 to 10.12%, respectively. The mesopore ratio of activated carbon increased with increasing activation time and was observed up to 78% at 973 K. This indicates that butane activity and retentivity could be a function not only of the specific surface area or total pore volume, but also of the mesopore volume fraction in the range of 2.8–3.8 nm and 5.5-6.5 nm of adsorbents, respectively. The AKC exhibit enhanced butane working capacity compared to commercial activated carbon with the high performance of butane working capacity due to its pore structure having a high mesopore ratio.

scholarly journals Activated Carbons from Thermoplastic Precursors and Their Energy Storage Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 896 ◽  
Author(s):  
Hye-Min Lee ◽  
Kwan-Woo Kim ◽  
Young-Kwon Park ◽  
Kay-Hyeok An ◽  
Soo-Jin Park ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Specific Surface ◽  
Surface Area ◽  
Field Emission ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Cross Linking ◽  
Mesopore Volume

In this study, low-density polyethylene (LDPE)-derived activated carbons (PE-AC) were prepared as electrode materials for an electric double-layer capacitor (EDLC) by techniques of cross-linking, carbonization, and subsequent activation under various conditions. The surface morphologies and structural characteristics of the PE-AC were observed by field-emission scanning electron microscope, Cs-corrected field-emission transmission electron microscope, and X-ray diffraction analysis, respectively. The nitrogen adsorption isotherm-desorption characteristics were confirmed by Brunauer–Emmett–Teller, nonlocal density functional theory, and Barrett–Joyner–Halenda equations at 77 K. The results showed that the specific surface area and total pore volume of the activated samples increased with increasing the activation time. The specific surface area, the total pore volume, and mesopore volume of the PE-AC were found to be increased finally to 1600 m2/g, 0.86 cm3/g, and 0.3 cm3/g, respectively. The PE-AC also exhibited a high mesopore volume ratio of 35%. This mesopore-rich characteristic of the activated carbon from the LDPE is considered to be originated from the cross-linking density and crystallinity of precursor polymer. The high specific surface area and mesopore volume of the PE-AC led to their excellent performance as EDLC electrodes, including a specific capacitance of 112 F/g.

scholarly journals Synthesis of activated carbon doped with transition metals for hydrogen storage

2019 ◽  
Vol 90 ◽  
pp. 01016 ◽  
Author(s):  
Nazlina Ya’aini ◽  
Arjun Pillay A/L Gopala Krishnan ◽  
Adnan Ripin
Keyword(s):  
Activated Carbon ◽  
Transition Metals ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
High Porosity ◽  
Carbon Doped ◽  
Copper Nickel ◽  
Bet Analysis ◽  
Oxygen Groups

Carbon materials with high porosity and surface area such as activated carbons with a combination of metal possess great materials to obtain maximum hydrogen adsorption via the hydrogen spillover effect. The properties of activated carbon doped with metals (copper, nickel and palladium) were studied to evaluate the capacity of hydrogen sorption on the materials. Characteristics of the activated carbon doped with copper (AC-Cu), nickel (AC-Ni) and palladium (AC-Pd) were evaluated using particle density test, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) and surface and pore analysis (BET). The performance of hydrogen adsorption of the materials was carried out at different pressures of 50, 100 and 150 psi. Characterization of the materials shows that FTIR spectroscopy manage to detect surface functional groups meanwhile the carbon structure and metal content was determined using XRD. BET analysis shows the presence of oxygen groups was decrease the specific surface area whereas the presence of transition metals had increased the surface area. Hydrogen adsorption test at 150 psi indicates that oxygen groups are not a good adsorption characteristic with only a maximum of 0.39 wt% of hydrogen was adsorbed compared to pristine activated carbon’s 0.42 wt% at 150 psi. The presence of transition metals, copper, nickel and palladium increased the overall hydrogen uptake with 0.52 wt%, 0.44 wt% and 0.62 wt% respectively at 150 psi.

Effect of Activating Agent on the Preparation of Bamboo-Based High Surface Area Activated Carbon by Microwave Heating

2016 ◽  
Vol 35 (6) ◽  
pp. 535-541 ◽  
Author(s):  
Hongying Xia ◽  
Jian Wu ◽  
Chandrasekar Srinivasakannan ◽  
Jinhui Peng ◽  
Libo Zhang
Keyword(s):  
Activated Carbon ◽  
Microwave Heating ◽  
Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Significant Proportion ◽  
Mixture Ratio ◽  
Activating Agent

AbstractThe present work attempts to convert bamboo into a high surface area activated carbon via microwave heating. Different chemical activating agents such as KOH, NaOH, K2CO3 and Na2CO3 were utilized to identify a most suitable activating agent. Among the activating agents tested KOH was found to generate carbon with the highest porosity and surface area. The effect of KOH/C ratio on the porous nature of the activated carbon has been assessed. An optimal KOH/C ratio of 4 was identified, beyond which the surface area as well as the pore volume were found to decrease. At the optimized KOH/C ratio the surface area and the pore volume were estimated to be 3,441 m2/g and 2.093 ml/g, respectively, with the significant proportion of which being microporous (62.3%). Activated carbon prepared under the optimum conditions was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Activated carbons with so high surface area and pore volume are very rarely reported, which could be owed to the nature of the precursor and the optimal conditions of mixture ratio adopted in the present work.

Adsorption and Desorption Behavior of Herbicide Using Bio-Based Materials

2019 ◽  
Vol 62 (6) ◽  
pp. 1435-1445 ◽  
Author(s):  
Saravanan Ramiah Shanmugam ◽  
Sushil Adhikari ◽  
Hyungseok Nam ◽  
Vivek Patil
Keyword(s):  
Activated Carbon ◽  
Pore Volume ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Agricultural Runoff ◽  
Kraft Lignin ◽  
Douglas Fir ◽  
Bet Surface Area ◽  
Runoff Water ◽  
Sorption Ability

HighlightsGlyphosate sorption using bio-based adsorbents was investigated in this study.Biochars showed poor sorption of glyphosate in comparison to the activated carbons.Total pore volume of bio-based adsorbents played a key role in sorption of glyphosate.Abstract. This study examined the glyphosate sorption ability of different bio-based materials, including biochars and activated carbons synthesized from Douglas fir, kraft lignin, and mixed wood pellets. All the biochars showed poor sorption of glyphosate in comparison to the activated carbons derived from biochars and the commercial powdered activated carbon (PAC) investigated in this study. All the biochar-derived activated carbons produced in the laboratory showed comparable glyphosate sorption in comparison to PAC. The activated carbons synthesized from Douglas fir biomass showed the highest glyphosate sorption among the activated carbons investigated. Langmuir and Freundlich isotherms were used to describe the adsorption kinetics of glyphosate onto activated carbons. Adsorption capacity showed better correlation (R2 = 0.989) with the total pore volume in comparison to the Brunauer-Emmett-Teller (BET) surface area and microporosity. The results of batch desorption tests indicated that the biochar-derived activated carbons and PAC showed >60% glyphosate retention. The results of this study indicate that activated carbons derived from biochars produced with thermochemical conversion processes could effectively sorb herbicide such as glyphosate similarly to commercial activated carbon and could be used either as a replacement for PAC in water treatment plants or for on-site treatment of agricultural runoff water. Keywords: Adsorption, Desorption, Herbicides, Kraft lignin, Model isotherms, Pore volume.

scholarly journals Some Surface Properties of Activated Carbons Prepared by Gasification with Different Gases

1997 ◽  
Vol 15 (9) ◽  
pp. 707-715 ◽  
Author(s):  
Amina A. Attia
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
Water Vapour ◽  
Pore Volume ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Surface Areas ◽  
Adsorption Of Nitrogen ◽  
Adsorption Of Water ◽  
Different Gases

A non-activated carbon ‘D’ was obtained by carbonizing date pits at 773 K in a limited supply of air. Activated carbons were obtained by gasifying portions of ‘D’ with air at 773 K, carbon dioxide at 1123 K, or steam at 1173 K, all to different burn-offs between 15% and 60%. The adsorption of nitrogen at 77 K and of carbon dioxide at 298 K was investigated using a volumetric adsorption apparatus of a conventional type. The adsorption of water vapour at 298 K and the chemisorption of pyridine at 423 K was followed by means of quartz spring balances. Gasification with oxidizing gases increased the surface area and total pore volume, as measured by nitrogen or carbon dioxide adsorption. In most cases, comparable surface areas were measured by nitrogen and carbon dioxide. The adsorption of water vapour depended on the percentage burn-off and the gasification conditions. Chemisorption of pyridine at 423 K was found to be related to the chemistry of the surface rather than to the surface area or total pore volume.

Optimization of Experimental Conditions for the Preparation of High Specific Surface Area Bamboo-Based Activated Carbon

2015 ◽  
Vol 1090 ◽  
pp. 154-159
Author(s):  
Sheng Zhou Zhang ◽  
Hong Ying Xia ◽  
Li Bo Zhang ◽  
Jin Hui Peng ◽  
Jian Wu ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Total Pore Volume ◽  
High Specific Surface Area ◽  
Raw Material ◽  
Experimental Conditions ◽  
Average Pore

Bamboo as the raw material is carbonized to prepare high specific surface area activated carbon by microwave heating under nitrogen atmosphere in our present work. Influences of activation agents on the preparation of activated carbon are studied. The results show that activation agents have a significant influence on the preparation of activated carbon. Under the heating time of 15 min, the adsorption capacity of the activated carbon prepared utilizing KOH as activation agent is the best. When the KOH/C ratio is 4, the iodine number and yield of activated carbon are 2298 mg/g and 39.82%, respectively. The BET specific surface area, total pore volume and average pore diameter of activated carbon are 3441 m2/g, 2.093 ml/g and 2.434 nm, respectively. The micropore volume of 1.304 ml/g is 62.30% of total pore volume, indicating that the activated carbon is microporous activated carbon.

Experimental Research on the Preparation of Porous Activated Carbon from Orange Wastes

2009 ◽  
Vol 79-82 ◽  
pp. 1907-1910
Author(s):  
Zhi Gang Xie
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Total Pore Volume ◽  
Carbonization Temperature ◽  
Bet Surface Area ◽  
Average Pore ◽  
Impregnation Ratio ◽  
Heat Preservation

Porous activated carbon was prepared from orange wastes using zinc chloride as an activating agent by one-step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on pore characteristics of activated carbon were studied. The porous structures of the orange wastes activated carbon were investigated by BET, D-R equations, BJH equations and Kelvin theory. The morphology was observed using transmission electron microscopy (TEM). The mesoporous activated carbon is gained when the impregnation ratio is 3:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has total pore volume 2.098 cm3/g, mesoporous pore volume 1.438 cm3/g, with a high BET surface area 1476m2/g. The pore distribution of the mesoporous activated carbon is very concentrative, with average pore diameter of 3.88nm. While, the high specific surface area activated carbon is gained when the impregnation ratio is 2:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has high BET surface area 1909 m2/g, while the total pore volume is only 1.448cm3/g and microporous pore volume is 0.889cm3/g, with average pore diameter of 2.29 nm.

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