Removal of Heavy Polynuclear Aromatics by Activated Carbons

2018 ◽  
Vol 775 ◽  
pp. 371-375 ◽  
Author(s):  
Wijai Pilawan ◽  
Wisanu Sirikarn ◽  
Kriangsak Kraiwattanawong
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Product Yield ◽  
Micropore Volume ◽  
Mesopore Volume ◽  
Complex Molecules ◽  
Waxy Oil ◽  
Mesopore Structure ◽  
Better Than ◽  
Polynuclear Aromatics

Heavy polynuclear aromatics (HPNA) is a complex molecules generated during hydrocracking process in waxy oil. HPNA is eliminated by a commercial activated carbon in the absorber to prevent the fouling in the pipelines and the decrease of product yield. In this work, the commercial activated carbons containing the different micropores and the different mesopores were selected to investigate the influence of pore structure on the HPNA removal. Here, the surface area of commercial activated carbons were quite equivalent. The results show that the activated carbon possessing the high mesopores can adsorb HPNA better than the activated carbon having the high micropores in spite of the summation of a micropore volume and a mesopore volume are quite equal. Therefore, the mesopore structure is a major role in the HPNA removal.

scholarly journals CO2 and CH4 Adsorption Behavior of Biomass-Based Activated Carbons

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3136 ◽  
Author(s):  
Deneb Peredo-Mancilla ◽  
Imen Ghouma ◽  
Cecile Hort ◽  
Camelia Matei Ghimbeu ◽  
Mejdi Jeguirim ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Textural Properties ◽  
Micropore Volume ◽  
Activation Method ◽  
Physical Activation

The aim of the present work is to study the effect of different activation methods for the production of a biomass-based activated carbon on the CO 2 and CH 4 adsorption. The influence of the activation method on the adsorption uptake was studied using three activated carbons obtained by different activation methods (H 3 PO 4 chemical activation and H 2 O and CO 2 physical activation) of olive stones. Methane and carbon dioxide pure gas adsorption experiments were carried out at two working temperatures (303.15 and 323.15 K). The influence of the activation method on the adsorption uptake was studied in terms of both textural properties and surface chemistry. For the three adsorbents, the CO 2 adsorption was more important than that of CH 4 . The chemically-activated carbon presented a higher specific surface area and micropore volume, which led to a higher adsorption capacity of both CO 2 and CH 4 . For methane adsorption, the presence of mesopores facilitated the diffusion of the gas molecules into the micropores. In the case of carbon dioxide adsorption, the presence of more oxygen groups on the water vapor-activated carbon enhanced its adsorption capacity.

scholarly journals Immersion Enthalpy of Activated Carbon–Cyclohexane and Activated Carbon–Hexane. Difference in the Solid–Liquid Interaction Enthalpy Due to the Structure of the Solvent

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 180
Author(s):  
Diana Hernández-Monje ◽  
Liliana Giraldo ◽  
Juan Moreno-Piraján
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Molecular Size ◽  
Liquid System ◽  
Micropore Volume ◽  
Immersion Enthalpy ◽  
Molecular Arrangement ◽  
The Difference ◽  
Enthalpy Of Immersion ◽  
Solid Liquid

The enthalpy of immersion for five activated carbons (with different surface chemistry) in cyclohexane and hexane was determined in order to observe the intensity of the solid–liquid interaction. The enthalpy of immersion was related to the properties of activated carbons, such as micropore volume, total basic groups content, and the EoWo product, that characterized each solid-liquid system. The values for the immersion enthalpy were between −21.2 and −91.7 J g−1 for cyclohexane and between −16.4 and −66.1 J g−1 for hexane. It showed greater interaction between the cyclohexane and the activated carbons and it was related to the properties of this adsorbate, such as molecular size and molecular arrangement. The difference in the enthalpy of immersion between the solvents per unit of micropore volume for the set of activated carbons was calculated obtaining a value of −487 J cm−3.

Characterization of Low-Pressure Nitrogen Plasma Discharge and Pre-Oxidation on the Surface Characteristics of Activated Carbons

2020 ◽  
Vol 998 ◽  
pp. 102-107
Author(s):  
Ria Grace Abdon ◽  
Top Archie Dela Peña ◽  
Camille Punongbayan ◽  
John Achilles Ricafrente
Keyword(s):  
Activated Carbon ◽  
Surface Morphology ◽  
Surface Area ◽  
Functional Groups ◽  
Activated Carbons ◽  
Low Pressure ◽  
Plasma Discharge ◽  
Total Surface Area ◽  
Micropore Volume ◽  
Nitrogen Plasma

Commercial activated carbon (CAC) was modified using low-pressure radio frequency nitrogen plasma discharge (NPD) operating at 0.3 mbar and 40 kHz. The surface chemistry of CAC was modified using HNO3 pre-oxidation to possibly influence the reactivity of NPD. The results of x-ray photoelectron spectroscopy (XPS) suggested that pre-oxidation reduces aromaticity, generates aliphatic carbons (C-C and C-H), and increases carboxylic functional groups (COOH) which probably enhances the nitrogen plasma functionalization based on the N/C ratio for CAC-O-P (4.29 %) compared to CAC-P (2.88 %). FTIR was used to confirm such effects of pre-oxidation from the functional groups present on the carbon surface. The total surface area was identified using Langmuir and Brunauer–Emmett–Teller (BET) N2 adsorption isotherms at 77 K. Both pre-oxidation and plasma treatment caused an increase in the surface area of CAC up to 150 percent. Carbon t-plot method was used to determine the micropore volume, micropore area, and external surface area. The total surface area of each activated carbon was mostly constituted of micropore area which was identified to be directly proportional to the micropore volume. Scanning electron microscope (SEM) confirms the destruction of the surface morphology for CAC-O that might have caused the increase in surface area. Development of surface threadlike structures were observed for the NPD treated CAC-O. NPD favors the development of NH2 functionalities and reduces the aromaticity of activated carbons while enhancing the surface morphology and the surface area.

scholarly journals Research on Powdered Activated Carbon Modification Using Chosen Chemical Methods

2021 ◽  
Vol 9 (1) ◽  
pp. 36
Author(s):  
Remigiusz Guminski ◽  
Iwona Skoczko
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Micropore Volume ◽  
Wood Material ◽  
Control Activity ◽  
Waste Wood ◽  
Carbon Modification ◽  
Study Results ◽  
Efficiency Control

Activated carbon has many applications in the environment, cosmetology, medicine and industry. The surface of each activated carbon can be modified to obtain the desired adsorption properties. Chemical activation can greatly affect the adsorption efficiency, control activity and application of the activated carbon. The aim of the study was to modify the selected activated carbon by chemical and physical methods, while maintaining these parameters so that it could be used in medicine. Powdered activated carbons with higher mechanical strength, large specific surface area and large macro-, meso- and micropore volume were prepared using natural waste wood material. This was followed by the digestion process and the washing of activated carbon. The study results indicate a significant influence of the centrifugal washing of activated carbon on the changes in the ash content and methylene index in the final product.

Use of activated carbon to remove undesirable residual amylase from refinery streams

2017 ◽  
pp. 96-103 ◽  
Author(s):  
Gillian Eggleston ◽  
Isabel Lima ◽  
Emmanuel Sarir ◽  
Jack Thompson ◽  
John Zatlokovicz ◽  
...  
Keyword(s):  
Activated Carbon ◽  
High Temperature ◽  
High Performance ◽  
Activated Carbons ◽  
Amylase Activity ◽  
Sugar Industry ◽  
End User ◽  
Customer Complaints ◽  
Carry Over ◽  
Very High

In recent years, there has been increased world-wide concern over residual (carry-over) activity of mostly high temperature (HT) and very high temperature (VHT) stable amylases in white, refined sugars from refineries to various food and end-user industries. HT and VHT stable amylases were developed for much larger markets than the sugar industry with harsher processing conditions. There is an urgent need in the sugar industry to be able to remove or inactivate residual, active amylases either in factory or refinery streams or both. A survey of refineries that used amylase and had activated carbon systems for decolorizing, revealed they did not have any customer complaints for residual amylase. The use of high performance activated carbons to remove residual amylase activity was investigated using a Phadebas® method created for the sugar industry to measure residual amylase in syrups. Ability to remove residual amylase protein was dependent on the surface area of the powdered activated carbons as well as mixing (retention) time. The activated carbon also had the additional benefit of removing color and insoluble starch.

Effect of Polyphosphate on Removal of Endocrine-Disrupting Chemicals of Nonylphenol and Bisphenol-A by Activated Carbons

2005 ◽  
Vol 40 (4) ◽  
pp. 484-490 ◽  
Author(s):  
Keun J. Choi ◽  
Sang G. Kim ◽  
Chang W. Kim ◽  
Seung H. Kim
Keyword(s):  
Activated Carbon ◽  
Bisphenol A ◽  
Surface Charge ◽  
Activated Carbons ◽  
Endocrine Disrupting Chemicals ◽  
Dipole Interaction ◽  
High Affinity ◽  
Calcium Polyphosphate ◽  
Endocrine Disrupting ◽  
Positively Charged

Abstract This study examined the effect of polyphosphate on removal of endocrine-disrupting chemicals (EDCs) such as nonylphenol and bisphenol-A by activated carbons. It was found that polyphosphate aided in the removal of nonylphenol and bisphenol- A. Polyphosphate reacted with nonylphenol, likely through dipole-dipole interaction, which then improved the nonylphenol removal. Calcium interfered with this reaction by causing competition. It was found that polyphosphate could accumulate on carbon while treating a river. The accumulated polyphosphate then aided nonylphenol removal. The extent of accumulation was dependent on the type of carbon. The accumulation occurred more extensively with the wood-based used carbon than with the coal-based used carbon due to the surface charge of the carbon. The negatively charged wood-based carbon attracted the positively charged calcium-polyphosphate complex more strongly than the uncharged coal-based carbon. The polyphosphate-coated activated carbon was also effective in nonylphenol removal. The effect was different depending on the type of carbon. Polyphosphate readily attached onto the wood-based carbon due to its high affinity for polyphosphate. The attached polyphosphate then improved the nonylphenol removal. However, the coating failed to attach polyphosphate onto the coal-based carbon. The nonylphenol removal performance of the coal-based carbon remained unchanged after the polyphosphate coating.

scholarly journals 1.8 V Aqueous Symmetric Carbon-Based Supercapacitors with Agarose-Bound Activated Carbons in an Acidic Electrolyte

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1731
Author(s):  
Chih-Chung Lai ◽  
Feng-Hao Hsu ◽  
Su-Yang Hsu ◽  
Ming-Jay Deng ◽  
Kueih-Tzu Lu ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Sulfuric Acid ◽  
Energy Density ◽  
Activated Carbons ◽  
High Energy ◽  
Aqueous Electrolytes ◽  
Alternative Material ◽  
Aqueous Cells ◽  
Acidic Electrolyte ◽  
Cycling Behavior

The specific energy of an aqueous carbon supercapacitor is generally small, resulting mainly from a narrow potential window of aqueous electrolytes. Here, we introduced agarose, an ecologically compatible polymer, as a novel binder to fabricate an activated carbon supercapacitor, enabling a wider potential window attributed to a high overpotential of the hydrogen-evolution reaction (HER) of agarose-bound activated carbons in sulfuric acid. Assembled symmetric aqueous cells can be galvanostatically cycled up to 1.8 V, attaining an enhanced energy density of 13.5 W h/kg (9.5 µW h/cm2) at 450 W/kg (315 µW/cm2). Furthermore, a great cycling behavior was obtained, with a 94.2% retention of capacitance after 10,000 cycles at 2 A/g. This work might guide the design of an alternative material for high-energy aqueous supercapacitors.

scholarly journals The influence of active carbon contaminants on the ozonation mechanism interpretation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lilla Fijołek ◽  
Joanna Świetlik ◽  
Marcin Frankowski
Keyword(s):  
Activated Carbon ◽  
Active Carbon ◽  
Alkali Metals ◽  
Activated Carbons ◽  
Carbon Surface ◽  
Bulk Solution ◽  
Ozone Decomposition ◽  
Reaction Products ◽  
Treatment Technology ◽  
Carbon Impurities

AbstractIn water treatment technology, activated carbons are used primarily as sorbents to remove organic impurities, mainly natural organic matter, but also as catalysts in the ozonation process. Commercially available activated carbons are usually contaminated with mineral substances, classified into two main groups: alkali metals (Ca, Na, K, Li, Mg) and multivalent metals (Al, Fe, Ti, Si). The presence of impurities on the carbon surface significantly affects the pHpzc values determined for raw and ozonated carbon as well as their acidity and alkalinity. The scale of the observed changes strongly depends on the pH of the ozonated system, which is related to the diffusion of impurities from the carbon to the solution. In an acidic environment (pH 2.5 in this work), the ozone molecule is relatively stable, yet active carbon causes its decomposition. This is the first report that indirectly indicates that contaminants on the surface of activated carbon (multivalent elements) contribute to the breakdown of ozone towards radicals, while the process of ozone decomposition by purified carbons does not follow the radical path in bulk solution. Carbon impurities also change the distribution of the reaction products formed by organic pollutants ozonation, which additionally confirms the radical process. The study showed that the use of unpurified activated carbon in the ozonation of succinic acid (SA) leads to the formation of a relatively large amount of oxalic acid (OA), which is a product of radical SA degradation. On the other hand, in solutions with purified carbon, the amount of OA generated is negligible.

scholarly journals Computer Analysis of the Effect of Activation Temperature on the Microporous Structure Development of Activated Carbon Derived from Common Polypody

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz
Keyword(s):  
Activated Carbon ◽  
Porous Structure ◽  
Computer Analysis ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Geometrical Parameters ◽  
Activation Process ◽  
Microporous Structure ◽  
Activation Temperature

This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity.

scholarly journals Preparation of High-Performance Activated Carbon from Coffee Grounds after Extraction of Bio-Oil

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 257
Author(s):  
Jie Ren ◽  
Nanwei Chen ◽  
Li Wan ◽  
Guojian Li ◽  
Tao Chen ◽  
...  
Keyword(s):  
Activated Carbon ◽  
High Performance ◽  
Average Pore Size ◽  
Total Pore Volume ◽  
Micropore Volume ◽  
Bet Surface Area ◽  
Average Pore ◽  
Activation Temperature ◽  
Coffee Grounds ◽  
Bio Oil

In this study, a new method for economical utilization of coffee grounds was developed and tested. The resulting materials were characterized by proximate and elemental analyses, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption–desorption at 77 K. The experimental data show bio-oil yields reaching 42.3%. The optimal activated carbon was obtained under vacuum pyrolysis self-activation at an operating temperature of 450 °C, an activation temperature of 600 °C, an activation time of 30 min, and an impregnation ratio with phosphoric acid of 150 wt.%. Under these conditions, the yield of activated carbon reached 27.4% with a BET surface area of 1420 m2·g−1, an average pore size of 2.1 nm, a total pore volume of 0.747 cm3·g−1, and a t-Plot micropore volume of 0.428 cm3·g−1. In addition, the surface of activated carbon looked relatively rough, containing mesopores and micropores with large amounts of corrosion pits.

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