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.

scholarly journals Thermodynamic study of the interactions of salicylic acid and granular activated carbon in solution at different pHs

2017 ◽  
Vol 36 (3-4) ◽  
pp. 833-850 ◽  
Author(s):  
Valentina Bernal ◽  
Liliana Giraldo ◽  
Juan C Moreno-Piraján
Keyword(s):  
Salicylic Acid ◽  
Activated Carbon ◽  
Aqueous Solutions ◽  
Activated Carbons ◽  
Granular Activated Carbon ◽  
Molecular Size ◽  
Carbon Surface ◽  
Immersion Enthalpy ◽  
Inappropriate Use

The inappropriate use of pain medication has led to the appearance of salicylic acid molecules (aspirin’s metabolite excretion) in surface water, which causes problems for the environment. The adsorption process using activated carbon is one of the processes that is used for the removal of organic compounds present in the aqueous phase; however, the percentage of removal depends on the physicochemical properties of the adsorbent and the adsorbate such as: pore size, surface area, surface chemistry, molecular size and solubility. In this work, we have studied the adsorbent–adsorbate interactions through the determination of the immersion enthalpy of the activated carbon in salicylic acid aqueous solutions; due to the solute and activated carbon surface have functional groups capable of ionized with the pH, the adsorption study was carried out at pH 2, 7, and 11. The activated carbons selected for the study were a granular activated carbon and a reduced activated carbon to 1173 K; as the immersion liquid were used salicylic acid aqueous solutions with concentrations between 0.072 mmol/ l and 0.72 mmol/ l, the solutions at pH 2 and 11 were prepared with HCl and NaOH solutions, respectively. It was determined that the immersion enthalpy is between −7.39 J /g and −22.5 J/g for the reduced activated carbon and between −7.63 J/g and −16.73 J/g for the granular activated carbon.

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 Calorimetry for the Characterization of PD Catalysts Supported on Activated Carbon

2009 ◽  
Vol 6 (4) ◽  
pp. 1221-1227
Author(s):  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Functional Groups ◽  
Activated Carbons ◽  
The Other ◽  
Pd Catalysts ◽  
Immersion Calorimetry ◽  
Characterization Techniques ◽  
The Difference

Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2and CO2isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.

scholarly journals Surface Area and Porosity Development on Granular Activated Carbon by Zirconium: Adsorption Isotherm Studies

2019 ◽  
Vol 16 (3) ◽  
Author(s):  
V. Sivanandan Achari ◽  
A. S. Rajalakshmi ◽  
S. Jayasree ◽  
Raichel Mary Lopez
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Granular Activated Carbon ◽  
Surface Characteristics ◽  
Isotherm Models ◽  
Activation Temperature ◽  
Adsorption Data ◽  
Solid Liquid

In this study, a new series of coconut shell based granular activated carbons (GAC) are prepared by impregnating with zirconium ions as zirconyl chloride and activated under superheated steam. These carbons are designated with activation temperature/ conditions as GAC 383 (activated at 383K), GACO 383 (HNO3 oxidised), GACZR 1273 (ZrOCl2 activated at 1273K) and GACOZR 1273 (HNO3 oxidised, ZrOCl2 activated at 1273K). Surface characteristics of these carbons are evaluated using Boehm titration methods, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction techniques (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The pore volume and the respective specific surface area of each carbon are determined by BET, I plot, Langmuir, Freundlich, and Dubinin-Radushkevich isotherms using N2 adsorption data at 77K. Analysis shows that zirconium ion enhances the surface area and porosity of granular activated carbon. The adsorption characteristics of newly prepared GAC are tested by solid-liquid equilibria using phenol as adsorbate. Equilibrium phenol adsorption data fitted to standard isotherm models of Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) equations. Adsorption constants and parameters indicate that zirconium impregnated granular activated carbons are relatively more efficient for the removal of phenol than the native carbon used.

scholarly journals Physicochemical Properties of Activated Carbon: Their Effect on the Adsorption of Pharmaceutical Compounds and Adsorbate–Adsorbent Interactions

2018 ◽  
Vol 4 (4) ◽  
pp. 62 ◽  
Author(s):  
Valentina Bernal ◽  
Liliana Giraldo ◽  
Juan Moreno-Piraján
Keyword(s):  
Activated Carbon ◽  
Physicochemical Properties ◽  
Activated Carbons ◽  
Pharmaceutical Compounds ◽  
Pharmaceutical Products ◽  
Adsorption Model ◽  
Immersion Enthalpy ◽  
Polar Groups ◽  
Adsorption Processes ◽  
Equilibrium Data

The adsorption of salicylic acid, acetaminophen, and methylparaben (pharmaceutical products derived from phenol) on carbons activated with different surface chemistries was carried out. We evaluated the effect of the physicochemical properties of the adsorbent and adsorbates on the adsorption capacity. A study of the adsorbate–adsorbent interactions via immersion calorimetry in the analytes solutions at different concentrations was included, in addition to the equilibrium data analysis. The results show that the pharmaceutical compounds (2.28–0.71 mmol g−1) have lower adsorption capacities in the activated carbon with the highest content of oxygenated groups (acids), while the activated carbons with amphoteric characteristics increase the capacities of adsorption (2.60–1.38 mmol g−1). This behavior may be associated with the increased affinity between the adsorbent and solvent due to the presence of polar groups, which was corroborated by the high immersion enthalpy value in water (ΔHimmH2O = −66.6 J g−1). The equilibrium data, adjusted to the Freundlich adsorption model, indicated that the heterogeneous adsorption processes involve immersion enthalpy values between −9.42 and −24.3 J g−1.

scholarly journals Highly effective removal of antibiotics from aqueous solution by magnetic ZnFe2O4/activated carbon composite

2020 ◽  
Vol 82 (5) ◽  
pp. 877-886
Author(s):  
Yun-Xia Li ◽  
Lei Wang ◽  
Fang-Fang Chai ◽  
Hong-Fei Jing ◽  
Zhu-Qing Gao ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Carbon Composite ◽  
Liquid System ◽  
Mechanism Analysis ◽  
Solution Ph ◽  
Adsorption Capacities ◽  
Effective Removal ◽  
Solid Liquid

Abstract Water pollution from antibiotics has attracted a lot of attention for its serious threat to human health. In this study, a magnetic adsorbent (zinc ferrite/activated carbon (ZnFe2O4/AC) was synthesized via microwave method to effectively remove gemifioxacin mesylate (GEM) and moxifloxacin hydrochloride (MOX). Based on the porosity of AC and the magnetism of ZnFe2O4, the resulting ZnFe2O4/AC has high adsorption capacities and can be easily separated from the solid–liquid system via a magnetic field. The largest adsorption capacities for GEM and MOX can reach up to 433.4 mg g−1 and 388.8 mg g−1, respectively, higher than those of reported adsorbents such as MIL-101 and MOF-808. Fastest adsorptions of GEM and MOX were found at 5 min, and solution pH and coexisting salts do not have a significant influence on the adsorption process. The adsorption mechanism analysis indicates that electrostatic interaction and H-bond interaction contribute to the effective adsorption.

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.

scholarly journals Adsorption of Carbon Monoxide (CO) in a Room by Coconut Shell and Durian Skin Activated Carbons

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Ulfa Nurullita ◽  
Mifbakhuddin Mifbakhuddin
Keyword(s):  
Carbon Monoxide ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Coconut Shell ◽  
Control Group ◽  
P Value ◽  
Randomized Control ◽  
The Difference ◽  
Co Reduction ◽  
One Way Anova

Cigarettes contain more than 4.000 elements, at least 200 of them are harmful to health. The main toxins are tar, nicotine, and carbon monoxide (CO). The purpose study was to know ability of coconut shell and durian skin activated carbon as adsorbent of CO. The study was pre-experimental with randomized control group only design. Independent variables are types of activated carbon, the dependent variable is concentration of CO. The results showed the lowest in durian skin activated carbon that 29 ppm. The average CO decreased on coconut shell is 68,7 ppm, durian skin is 77,478 ppm. One way anova test to see the difference CO in various of activated carbon p value 0,0001, independent t test to see the difference CO reduction between 2 types activated carbon with p value is 0,0001. Conclusion: there is a differences adsorbtion of CO between coconut shell and durian skin activated carbon.

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