Effect of Activated Carbon Fiber Properties on Ca2+ Removal by Capacitive Deionization

2014 ◽  
Vol 700 ◽  
pp. 281-285
Author(s):  
Qing Jun Gao ◽  
Xue Xin Liu ◽  
Lei Yuan ◽  
Kai Zhang
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Activated Carbon Fiber ◽  
Activated Carbon Fibers ◽  
Capacitive Deionization ◽  
Average Pore ◽  
Fiber Properties

Three activated carbon fibers, namely Sample A, B, and C, were used as electrodes for Ca2+ removal by capacitive deionization in this study. The physical properties of ACFs were comprehensively investigated with regard to surface area, pore volume, pore size distribution, specific capacitance, and contact angle. An internal correlation was intended to reveal between the ACF properties and their CDI performance. Pseduo-first-order adsorption kinetics model could successfully depict the Ca2+ removal with different ACF electrodes. Based on the fitting parameters, Sample B with the highest pore volume, specific capacitance, and hydrophilicity exhibited the highest equilibrium electrosorption capacity (9.977 mg-Ca2+/g-ACF). However, Sample A with the highest average pore diameter (2.4 nm) has the highest rate constant (0.074/min). Even though the abundant micropores with diameters less than 2 nm created large specific surface area in Sample C, its uptake of Ca2+ was not as good as that of Sample A.

Modified polyacrylonitrile-based activated carbon fibers applied in supercapacitor

2016 ◽  
Vol 45 (3) ◽  
pp. 164-171 ◽  
Author(s):  
Linjie Su ◽  
Bohong Li ◽  
Dongyu Zhao ◽  
Chuanli Qin ◽  
Zheng Jin
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Electrode Material ◽  
High Specific Capacitance ◽  
Activated Carbon Fibers ◽  
Content Type

Purpose The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor. Design/methodology/approach In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test. Findings It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers. Originality/value The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.

scholarly journals Carbon Dioxide Adsorption on Porous and Functionalized Activated Carbon Fibers

2019 ◽  
Vol 9 (10) ◽  
pp. 1977 ◽  
Author(s):  
Yu-Chun Chiang ◽  
Cheng-Yu Yeh ◽  
Chih-Hsien Weng
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Co2 Adsorption ◽  
Physical Adsorption ◽  
Koh Activation ◽  
Co2 Uptake ◽  
Activated Carbon Fibers

Polyacrylonitrile-based activated carbon fibers (ACFs), modified using potassium hydroxide (KOH) or tetraethylenepentamine (TEPA), were investigated for carbon dioxide (CO2) adsorption, which is one of the promising alleviation approaches for global warming. The CO2 adsorption isotherms were measured, and the values of isosteric heat of adsorption were calculated. The results showed that the KOH-modified ACFs exhibited a great deal of pore volume, and a specific surface area of 1565 m2/g was obtained. KOH activation made nitrogen atoms easily able to escape from the surface of ACFs. On the other hand, the surface area and pore volume of ACFs modified with TEPA were significantly reduced, which can be attributed to the closing or blocking of micropores by the N-groups. The CO2 adsorption on the ACF samples was via exothermic reactions and was a type of physical adsorption, where the CO2 adsorption occurred on heterogeneous surfaces. The CO2 uptakes at 1 atm and 25 °C on KOH-activated ACFs reached 2.74 mmole/g. This study observed that microporosity and surface oxygen functionalities were highly associated with the CO2 uptake, implying the existence of O-C coordination, accompanied with physical adsorption. Well cyclability of the adsorbents for CO2 adsorption was observed, with a performance decay of less than 5% over up to ten adsorption-desorption cycles.

Microstructure and Oxygen Functional Groups on Modified Liquefied Wooden Activated Carbon Fibers with Hydrogen Peroxide

2013 ◽  
Vol 433-435 ◽  
pp. 2003-2007 ◽  
Author(s):  
Wei Gao ◽  
Gaungjie Zhao
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Surface Area ◽  
Functional Groups ◽  
Carbon Fibers ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Activated Carbon Fibers ◽  
Average Pore ◽  
Oxygen Functional Groups

The aim of this study is to investigate changes in microstructure and oxygen functional groups of liquefied wood activated carbon fibers using density functional theory, FTIR, X-ray photoelectron spectroscopy. Samples were immersed with hydrogen peroxide (H2O2) at three concentrations (15, 20, and 25 wt%), three temperatures (90, 70, and 50 °C) for three periods of time (1, 2, and 3 h). The results reveals that the pores average radius narrow, and micropores turn into mesopores or macropores with the increasing process, which brings about the surface area of treated samples decrease. Numerous oxygen functional groups are observed in the treated samples, and the ratios of oxygen and carbon increase from 3.2% before treated to 14.7% with H2O2 modification. The results confirm that the average pore radius and surface area decrease during treatment due to concentration and temperature. What is more, oxygen functional groups increase significantly with increasing treatment concentration.

Sustainable activated carbon fibers from liquefied wood with controllable porosity for high-performance supercapacitors

2014 ◽  
Vol 2 (30) ◽  
pp. 11706-11715 ◽  
Author(s):  
Zhi Jin ◽  
Xiaodong Yan ◽  
Yunhua Yu ◽  
Guangjie Zhao
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Fibers ◽  
High Performance ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Activated Carbon Fibers ◽  
Micropore Surface Area ◽  
Liquefied Wood

The combination of the high micropore surface area and the controlled mesopore size and mesopore/micropore ratio is responsible for high specific capacitance and excellent rate capability.

scholarly journals Pitch-Derived Activated Carbon Fibers for Emission Control of Low-Concentration Hydrocarbon

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1313 ◽  
Author(s):  
Hye-Min Lee ◽  
Byeong-Hoon Lee ◽  
Soo-Jin Park ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Volume Fraction ◽  
Structural Characteristics ◽  
Total Pore Volume ◽  
Activated Carbon Fibers

The unburned hydrocarbon (HC) emissions of automobiles are subject to strong regulations because they are known to be converted into fine dust, ozone, and photochemical smog. Pitch-based activated carbon fibers (ACF) prepared by steam activation can be a good solution for HC removal. The structural characteristics of ACF were observed using X-ray diffraction. The pore characteristics were investigated using N2/77K adsorption isotherms. The butane working capacity (BWC) was determined according to ASTM D5228. From the results, the specific surface area and total pore volume of the ACF were determined to be 840–2630 m2/g and 0.33–1.34 cm3/g, respectively. The butane activity and butane retentivity of the ACF increased with increasing activation time and were observed to range between 15.78–57.33% and 4.19–11.47%, respectively. This indicates that n-butane adsorption capacity could be a function not only of the specific surface area or total pore volume but also of the sub-mesopore volume fraction in the range of 2.0–2.5 nm of adsorbents. The ACF exhibit enhanced BWC, and especially adsorption velocity, compared to commercial products (granules and pellets), with lower concentrations of n-butane due to a uniformly well-developed pore structure open directly to the outer surface.

scholarly journals Asymmetric Electrodes Constructed with PAN-Based Activated Carbon Fiber in Capacitive Deionization

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mingzhe Li ◽  
Yingzhi Chen ◽  
Zheng-Hong Huang ◽  
Feiyu Kang
Keyword(s):  
Activated Carbon ◽  
Carbon Fibers ◽  
Activated Carbon Fiber ◽  
Activated Carbon Fibers ◽  
Capacitive Deionization ◽  
Reverse Voltage ◽  
Forward Voltage ◽  
Adsorption Ability ◽  
Low Energy Consumption ◽  
Asymmetric Electrodes

Capacitive deionization (CDI) method has drawn much attention for its low energy consumption, low pollution, and convenient manipulation. Activated carbon fibers (ACFs) possess high adsorption ability and can be used as CDI electrode material. Herein, two kinds of PAN-based ACFs with different specific surface area (SSA) were used for the CDI electrodes. The CDI performance was investigated; especially asymmetric electrodes’ effect was evaluated. The results demonstrated that PAN-based ACFs showed a high electrosorption rate (complete electrosorption in less than half an hour) and moderate electrosorption capacity (up to 0.2 mmol/g). CDI experiments with asymmetric electrodes displayed a variation in electrosorption capacity between forward voltage and reverse voltage. It can be attributed to the electrical double layer (EDL) overlap effect and inner pore potential; thus the ions with smaller hydrated ionic radius can be adsorbed more easily.

scholarly journals Enhanced Photo-Catalytic Performance of Activated Carbon Fibers for Water Treatment

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1794 ◽  
Author(s):  
Konstantinos V. Plakas ◽  
Athina Taxintari ◽  
Anastasios J. Karabelas
Keyword(s):  
Activated Carbon ◽  
Carbon Fibers ◽  
Treatment Time ◽  
Catalytic Performance ◽  
Dip Coating ◽  
Activated Carbon Fiber ◽  
Activated Carbon Fibers ◽  
Tio2 Sample ◽  
Phenol Adsorption ◽  
Electrophoretic Coating

The synthesis, characterization, and performance of composite photocatalytic adsorbents are investigated in this work using the dip-coating and the electrophoretic coating methods for the deposition of titanium dioxide (TiO2) on porous activated carbon fiber (ACF) substrates. The adsorption and photocatalytic efficiency of the synthesized catalytic adsorbents were compared using phenol as the model pollutant. Both immobilization techniques resulted in composite ACF/TiO2 adsorbents characterized by large surface area (844.67 ± 45.58 m2 g−1), uniform distribution of TiO2 nanoparticles on the activated carbon fibers, and high phenol adsorption. The method and the treatment time affected the phenol adsorption, while the highest sorption was determined in the case of the ACF/TiO2 sample prepared by the electrophoretic coating method (at 20 V) for an electrolysis time of 120 s (7.93 mgphenol g−1ACF/TiO2). The UV-A irradiation of most ACF/TiO2 samples led to a faster removal of phenol from water as a result of the combined sorption and heterogeneous photocatalysis. The stability and the effective regeneration of the most promising composite photocatalytic adsorbent was proved by multiple filtration and UV-A irradiation cycles.

scholarly journals Photoconductivity of activated carbon fibers

1991 ◽  
Vol 6 (5) ◽  
pp. 1040-1047 ◽  
Author(s):  
K. Kuriyama ◽  
M.S. Dresselhaus
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Low Temperatures ◽  
Room Temperature ◽  
High Surface ◽  
Localized States ◽  
Activated Carbon Fibers ◽  
Disordered Carbon ◽  
Increasing Temperature

The conductivity and photoconductivity are measured on a high-surface-area disordered carbon material, i.e., activated carbon fibers, to investigate their electronic properties. This material is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000–2000 m2/g. Our preliminary thermopower measurements show that the dominant carriers are holes at room temperature. The x-ray diffraction pattern reveals that the microstructure is amorphous-like with Lc ≃ 10 Å. The intrinsic electrical conductivity, on the order of 20 S/cm at room temperature, increases by a factor of several with increasing temperature in the range 30–290 K. In contrast, the photoconductivity in vacuum decreases with increasing temperature. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The recombination kinetics changes from a monomolecular process at room temperature to a bimolecular process at low temperatures, indicative of an increase in the photocarrier density at low temperatures. The high density of localized states, which limits the motion of carriers and results in a slow recombination process, is responsible for the observed photoconductivity.

Activated carbon fiber from liquefied wood and polyvinyl butyral as an additive for production of flexible all-carbon yarn supercapacitors

Holzforschung ◽  
2018 ◽  
Vol 72 (5) ◽  
pp. 367-374 ◽  
Author(s):  
Yuxiang Huang ◽  
Wenji Yu ◽  
Guangjie Zhao
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
High Surface ◽  
High Surface Area ◽  
Polyvinyl Butyral ◽  
Activated Carbon Fiber ◽  
Bet Surface Area ◽  
Liquefied Wood ◽  
New Material

AbstractA novel way to prepare mesoporous activated carbon fibers (ACFs-P) has been developed, while the ACFs-P with high surface area were obtained from liquefied wood by combining polyvinyl butyral (PVB) blending and steam activation. The porosity properties of the new material was investigated by N2adsorption and the Brunauer–Emmett–Teller (BET) surface area was found to be 2710 m2g−1and a pore volume of 1.540 cm3g−1, of which 58.2% was mesoporous with diameters between 3 and 6 nm. ACFs-P had a higher methylene blue (MB) adsorption capacity (962 mg/g) than the PVB-added carbon fibers (CFs-P) and ACFs-P without PVB (ACFs-C). Flexible all-carbon yarn supercapacitors can be produced from ACFs-P as powder or fiber. The fiber approach led to yarn supercapacitors with a less favorable electrochemical performance than the powder based production owing to the poor strength of the fibers. A 10 cm long yarn supercapacitor from the powdered ACFs exhibited a high specific length capacitance of 43 mF cm−1at 2 mV s−1. Yarn supercapacitors showed an excellent mechanical flexibility and its capacitor properties were not diminished after bending or crumpling.

scholarly journals Preparation and photocatalytic activity characterization of activated carbon fiber–BiVO4 composites

RSC Advances ◽  
2018 ◽  
Vol 8 (43) ◽  
pp. 24665-24672 ◽  
Author(s):  
Chencheng Zhang ◽  
Pingfang Han ◽  
Xiaoping Lu ◽  
Qinghui Mao ◽  
Jiangang Qu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Performance Evaluation ◽  
Activated Carbon ◽  
Carbon Fibers ◽  
Photocatalytic Performance ◽  
Activated Carbon Fiber ◽  
Activated Carbon Fibers ◽  
Experimental Conditions ◽  
Characterization Of Activated Carbon

Herein, we describe the hydrothermal immobilization of BiVO4 on activated carbon fibers, using Reactive Black KN-B photocatalytic performance evaluation and establishing the experimental conditions yielding maximalphotocatalytic activity.

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