scholarly journals Activation of electrospun carbon fibers: the effect of fiber diameter on CO2 and steam reaction kinetics

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
Johannes Erben ◽  
Alenica Heußner ◽  
Simon Thiele ◽  
Sven Kerzenmacher
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Nonlinear Behavior ◽  
Steam Activation ◽  
Activation Temperature ◽  
Activation Kinetics ◽  
Fiber Mats ◽  
Rate Controlled ◽  
Surface Area Increase ◽  
Kinetics Of

AbstractFirst, we present a fabrication process for electrospun carbon fiber mats with mean fiber diameters between 108 nm and 623 nm. The carbon fiber mats were produced by electrospinning of polyacrylonitrile (PAN) solutions and subsequent carbonization. The fiber mats feature small variations of their properties that are required for parameter studies. Second, we investigate the kinetics of steam and CO2 activation with three different activation temperatures and times. Both activation methods result in a surface area increase depending on activation temperature and time. Detailed analysis of the macroscopic properties burn-off, surface area, and conductivity reveals insights into the microscopic activation kinetics. The different fiber diameters of the carbon fiber mats enable the distinction of surface driven and bulk processes. Our results indicate, that CO2 activation kinetics are mass transport controlled, and that steam activation kinetics are reaction rate controlled. The turbostratic nature of PAN derived carbon and the distinct characteristics of the activation agents could explain the nonlinear behavior of the burn-off and surface area development.

scholarly journals Integrated approach in treatment of solid olive residue and olive wastewater

2021 ◽  
Author(s):  
Tariq Altalhi ◽  
A. Abd El-moemen ◽  
Mohamed M. Ibrahim ◽  
Amine Mezni ◽  
Ibrahim Hotan Alsohaimi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Integrated Approach ◽  
Polyphenolic Compounds ◽  
Steam Activation ◽  
Activation Temperature ◽  
Removal Capacity ◽  
Olive Residue ◽  
By Products

Abstract Olive oil production processes breed two kinds of environmentally detriment waste by-products; the solid olive residue (SOR) and olive waste water (OWW) by-products. The current work aims to treat simultaneously both wastes in the same location. The solid olive residue was converted to activated carbon with pyrolysis at 600°C, followed by steam activation at 600, 700 and 800°C. The produced activated carbons were investigated by FTIR, SEM, BET surface areas analyzer and iodine number. The surface area increases with increasing stream activation temperature up to 800°C (1020 m2/g BET). However, steam activation at 700°C is most environmental and economically feasible, because increasing the activation temperature from 700 to 800°C increases the surface area only from 979 to 1020 m2/g. Activated carbon steam cured at 700°C shows high removal capacity of both polyphenolic compounds and COD of OWW. 95.5% of COD and 84.2% of polyphenolic compounds was removed after equilibrium with activated carbon for 2 hours at room temperature.

Textural Characteristics of Coconut Shell-Based Activated Carbons with Steam Activation

2012 ◽  
Vol 608-609 ◽  
pp. 366-373 ◽  
Author(s):  
Xin Ying Wang ◽  
Dan Xi Li ◽  
Bao Min Yang ◽  
Wei Li
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Activated Carbons ◽  
Hold Time ◽  
Micropore Volume ◽  
Steam Activation ◽  
Activation Temperature ◽  
Water Steam

Activated carbons were prepared from coconut shells by using carbonization at 600 °C for 2 h followed by water steam activation. Effects of activation temperature, hold time and water steam amount on the yield, BET surface area and micropore volume of activated carbons were evaluated. The pore structure of the activated carbon was characterized by N2 adsorption at 77K. Surface area, micropore volume and pore size distribution (PSD) of the carbons were determined by the Brunauer–Emmett–Teller (BET) equation, Dubinin–Astakhov (DA) and the Non-Local Density Functional Theory (NLDFT) methods, respectively. The results show that activated carbons with specific surface area of 1500 m2/g and pore size lower than 2 nm can be produced at 900 °C for 1~2 h. Hold time could be reduced by increasing steam amount and activation temperature, but micropore was enlarged and yield was decreased. Increasing hold time could produce more micropores when steam amount and activation temperature were more appropriate. Pore size distribution shows that activated carbons are microporous dominant.

Activated Carbon Fiber for Super-Capacitor Electrode

2010 ◽  
Vol 97-101 ◽  
pp. 510-513 ◽  
Author(s):  
Xue Jun Zhang ◽  
Hai Yan Li ◽  
Yan Hong Tian
Keyword(s):  
Activated Carbon ◽  
Carbon Fiber ◽  
Surface Area ◽  
Activation Method ◽  
Bet Surface Area ◽  
Electrochemical Performances ◽  
Cyclic Voltammograms ◽  
Steam Activation ◽  
Catalytic Activation ◽  
Capacitance Performance

Activated carbon fibers(ACFs) were prepared from general pitch-based carbon fiber by steam activation and catalytic activation method, respectively. The surface area and pore structure of the resultant ACFs were analyzed by N2 adsorption, and electrochemical performances as electrodes of super capacitors were characterized by galvanostatic, cyclic voltammograms and AC impedance spectrum analysis. The results show that ACFs prepared by both methods have similar BET surface area, while their pore size and distribution are different. Compared with steam activation, catalytic activation results in ACFs with high mesoporosity of 40%. The electrode performances show that the specific capacitances of ACFs prepared by catalytic activation method could be 213 F/g, two times of that of ACFs prepared by steam activation method, and more mesopores are the reason for the good capacitance performance.

scholarly journals Preparation of a Photosensitive Composite Carbon Fiber for Spilled Oil Cleaning

2022 ◽  
Vol 6 (1) ◽  
pp. 28
Author(s):  
Yong X. Gan ◽  
Ali Arjan ◽  
Jimmy Yik
Keyword(s):  
Titanium Dioxide ◽  
Carbon Fiber ◽  
Surface Area ◽  
Composite Fiber ◽  
Active Surface Area ◽  
Fiber Mats ◽  
Metallic Compounds ◽  
Oxide Particles ◽  
Spilled Oil ◽  
Composite Carbon

This paper deals with preparing a functional composite carbon fiber with a large surface area for spilled oil cleaning. The composite fiber consisted of photosensitive oxide particles and polymer-derived carbon. It was made by co-spinning the polymer and metallic compounds. After heat treatment at high temperatures, an activated carbon fiber containing oxide particles was obtained. The particles were found distributed in the fiber and at the surface of the fiber. The composite fiber was found sensitive to sunlight. Fiber mats made of the composite fiber possessed a high surface area for oil absorption and removal. Cobalt(II) titanate particles were obtained from the reaction of titanium dioxide and cobalt oxide. The reaction happened in situ through the hydrolysis of metallic compounds in the spun fiber. The titanium dioxide and cobalt(II) titanate particle-containing fibers demonstrated the photoactivity in the visible light spectrum. It was concluded that particle-containing composite carbon fiber mats can be prepared successfully by co-electrospinning. Due to the oleophilic property and the high active surface area, the composites are suitable for spilled oil cleaning through fast absorption.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

scholarly journals Development and Characterization of Composite Carbon Adsorbents with Photocatalytic Regeneration Ability: Application to Diclofenac Removal from Water

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Velma Beri Kimbi Yaah ◽  
Satu Ojala ◽  
Hamza Khallok ◽  
Tiina Laitinen ◽  
Marcin Selent ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Palm Kernel ◽  
Hydrothermal Carbonization ◽  
Carbon Composite ◽  
Carbon Adsorbents ◽  
Regeneration Ability ◽  
Activation Temperature

This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO2, and W followed by activation at 400 °C under N2 flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO2, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m2g−1, while for HCP25, it was 160 m2g−1. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO2- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.

scholarly journals Effect of Glycero-(9,10-trioxolane)-trialeate on the Physicochemical Properties of Non-Woven Polylactic Acid Fiber Materials

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2517
Author(s):  
Anatoliy Olkhov ◽  
Olga Alexeeva ◽  
Marina Konstantinova ◽  
Vyacheslav Podmasterev ◽  
Polina Tyubaeva ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Polylactic Acid ◽  
Specific Surface Area ◽  
Water Sorption ◽  
Fiber Surface ◽  
High Water ◽  
Scanning Calorimetry ◽  
Fiber Mats ◽  
Fiber Materials

Biocompatible glycero (9,10-trioxolane) trioleate (ozonide of oleic acid triglyceride, OTOA) was incorporated into polylactic acid (PLA) fibers by electrospinning and nonwoven PLA mats with 1%, 3% and 5% OTOA content. The morphological, mechanical, thermal and water sorption properties of electrospun PLA mats after the addition of OTOA were studied. A morphological analysis showed that the addition of OTOA increased the average fiber diameter and induced the formation of pores on the fiber surface, leading to an increase in the specific surface area for OTOA-modified PLA fibrous mats. PLA fiber mats with 3% OTOA content were characterized by a highly porous surface morphology, an increased specific surface area and high-water sorption. Differential scanning calorimetry (DSC) was used to analyze the thermal properties of the fibrous PLA mats. The glass transition temperatures of the fibers from the PLA–OTOA composites decreased as the OTOA content increased, which was attributed to the plasticizing effect of OTOA. DSC results showed that OTOA aided the PLA amorphization process, thus reducing the crystallinity of the obtained nonwoven PLA–OTOA materials. An analysis of the mechanical properties showed that the tensile strength of electrospun PLA mats was improved by the addition of OTOA. Additionally, fibrous PLA mats with 3% OTOA content showed increased elasticity compared to the pristine PLA material. The obtained porous PLA electrospun fibers with the optimal 3% OTOA content have the potential for various biomedical applications such as drug delivery and in tissue engineering.

scholarly journals Effect of Air Oxidation on Texture, Surface Properties and Dye Adsorption of Wood-Derived Porous Carbon Materials

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1675 ◽  
Author(s):  
Suhong Ren ◽  
Liping Deng ◽  
Bo Zhang ◽  
Yafang Lei ◽  
Haiqing Ren ◽  
...  
Keyword(s):  
Surface Area ◽  
Functional Groups ◽  
Porous Carbon ◽  
Carbon Materials ◽  
Dye Adsorption ◽  
Carbon Surface ◽  
Air Oxidation ◽  
Activation Temperature ◽  
Porous Carbon Materials ◽  
Hierarchical Porous

Hierarchical porous carbon materials made from cork were fabricated using a facile and green method combined with air activation, without any templates and chemical agents. The influence of air activation on the texture and other surface characteristics of the carbon materials were evaluated by various characterization techniques. Results indicate that air oxidation can effectively improve the surface area and the hierarchical porous structure of carbon materials, as well as increase the number of oxygen-containing functional groups on the carbon surface. The specific surface area and the pore volume of the carbon material activated by air at 450 °C (C800-M450) can reach 580 m2/g and 0.379 cm3/g, respectively. These values are considerably higher than those for the non-activated material (C800, 376 m2/g, 0.201 cm3/g). The contents of the functional groups (C–O, C=O and O–H) increased with rising activation temperature. After air activation, the adsorption capacity of the carbon materials for methylene blue (MB) and methyl orange (MO) was increased from 7.7 and 6.4 mg/g for C800 to 312.5 and 97.1 mg/g for C800-M450, respectively. The excellent dye removal of the materials suggests that the porous carbon obtained from biomass can be potentially used for wastewater treatment.

Thermal, Raman and surface area studies of microcoiled carbon fiber synthesized by CVD microwave system

2002 ◽  
Vol 76 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Jining Xie ◽  
Pramod K Sharma ◽  
V.V Varadan ◽  
V.K Varadan ◽  
Bhabendra K Pradhan ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Area Studies ◽  
Microwave System

Preparation and Characterization of Activated Carbon Fibers from Jute Fibers by Phosphoric Acid Activation

2012 ◽  
Vol 184-185 ◽  
pp. 1110-1113 ◽  
Author(s):  
Li Fen He ◽  
Qi Xia Liu ◽  
Tao Ji ◽  
Qiang Gao
Keyword(s):  
Activated Carbon ◽  
Carbon Fiber ◽  
Phosphoric Acid ◽  
Carbon Fibers ◽  
Activated Carbon Fibers ◽  
Optimum Conditions ◽  
Activation Time ◽  
Activation Temperature ◽  
Jute Fibers ◽  
Activating Agent

Various jute-based activated carbon fibers were prepared by using jute fibers as raw materials and phosphoric acid as activating agent. The effects of three main factors such as concentration of activating agent, activation temperature and activation time on the yield and adsorptive properties of active carbon fibers were investigated via orthogonal experiments. The surface physical morphology of jute-based activated carbon fiber was also observed by using Scanning Electron Microscope. Results showed that the optimum conditions were phosphoric acid concentration of 4 mol/L, activation temperature of 600 °C and activation time of 1h. The yield, iodine number and amount of methylene blue adsorption of the active carbon fiber prepared under optimum conditions were 37.99 %, 1208.87 mg/g and 374.65 mg/g, respectively.

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