Immersion enthalpy of carbonaceous samples in aqueous solutions of monohydroxilated phenols

Blanco-Martínez, Diego A.; Giraldo, Liliana; Moreno–Piraján, Juan Carlos

doi:10.1007/s10973-009-0057-9

Cited by 12 publications

(4 citation statements)

References 16 publications

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Section: Resultsmentioning

confidence: 99%

“…CAON had the lowest value (1.43) due to its surface chemistry since it would have a low affinity for nonpolar substances such as these hydrocarbons. When the surface oxygenated groups were reduced due to thermal treatment, the hydrophobic factor increased because there was a greater affinity for nonpolar substances, which made the intensity of the interaction between these hydrocarbons C 6 and the samples higher …”

Section: Resultsmentioning

confidence: 99%

“…When the surface oxygenated groups were reduced due to thermal treatment, the hydrophobic factor increased because there was a greater affinity for nonpolar substances, which made the intensity of the interaction between these hydrocarbons C 6 and the samples higher. 34 Figure 1 shows the histogram of the pore size distribution of CAG, CAON, and CAG1173. The QSDFT model for mixed slit pore/cylindrical pore geometry was chosen because this determination was also made for the other pore geometries and it showed a lower percentage of error (CAG: 0.97%, CAON: 0.97%, CAON723: 1.10%, CAON1023: 1.61%, and CAG1173: 1.47%).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

2019

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Adsorption isotherms of benzene, cyclohexane, and hexane were determined from the gas phase on microporous activated carbons with Brunauer–Emmett–Teller areas between 816 and 996 m2 g–1. The Dubinin–Radushkevich equation was used to calculate the parameters of characteristic energy Eo and micropore volume Wo. Also, immersion enthalpies of activated carbons in solvents were obtained (benzene: −95.0 to −145.1 J g–1; cyclohexane: −21.2 to −91.7 J g–1; and hexane: −16.4 to −66.1 J g–1), and they were used to calculate the product EoWo with the Stoeckli and Kraehenbuehl equations. Subsequently, values of EoWo from the two techniques (between 512 and 2223 J cm3 mol–1 g–1 for the adsorption isotherms; between 1204 and 12008 J cm3 mol–1 g–1 for immersion enthalpies) were correlated with some characteristics of the adsorbate such as molecular size, the molar volume, and the dielectric constant. It was found that modifying the activated carbon affected the adsorption process, being favored by temperature changes and restricted by oxidation processes. The adsorbate, which showed the highest values for EoWo, was benzene, because it had a smaller molecular size and a higher dielectric constant.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

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Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

2019

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“…The enthalpies of immersion of the porous solids were determined in three solvents: water, benzene, and dichloromethane, in a heat conduction microcalorimeter, which measured the flow of heat through thermopiles of semiconductor materials installed in an aluminum block into which was inserted a stainless-steel cell of 10 mL capacity where the solvent was placed. 50 A sample of the solid (0.100 g) was weighed in a glass ampoule which was placed in the calorimetric cell, and the electric potential was measured for approximately 40 min to get a stable baseline. After that, the glass bulb breakage takes place and the generated thermal effect is recorded while the potential readings continue for 15 min more.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Adsorption of CO₂ on Activated Carbons Prepared by Chemical Activation with Cupric Nitrate

2020

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Activated carbons were prepared from a lignocellulosic material, African palm shells (Elaeis guineensis), by chemical impregnation of the precursor with solutions of 1–7% w/v Cu(NO3)2 at five different concentrations. These were carbonized in a carbon dioxide atmosphere at 1073 K to obtain different carbons. Their textural properties were characterized by nitrogen and carbon dioxide adsorption isotherms in order to evaluate the pore-size distribution. The immersion enthalpies of the activated carbons in benzene, dichloromethane, and water were determined. The CO2 adsorption capacities of the materials at 273 K under low-pressure conditions were also determined. Chemical characterization was performed by mass spectrometry, Fourier transform infrared spectroscopy, and temperature-programmed reduction. With this method of preparation under the concentrations described, activated micro–mesoporous carbons were obtained, with the formation of highly mesoporous solids that favored the process of diffusion of molecules of CO2 into the material. Here, we show that activated carbons were obtained with different textural characteristics: surface Brunauer–Emmett–Teller areas varied between 473 and 1361 m2 g–1 and micropore volume between 0.18 and 0.51 cm3 g–1. The activated carbon with the highest values of textural parameters was ACCu5-1073. Micro–mesoporous solids were obtained with the methodology used. This is important as it may help the entry of CO2 molecules into the pores. The adsorption of CO2 in the materials prepared presented values between 103 and 217 mg CO2 g–1; the values of volume of narrow microporosity obtained were between 0.16 and 0.45 cm3 g–1. The solid with the greatest capacity for adsorption of CO2 and volume of narrow microporosity was ACCu3-1073. The use of these solids is of importance for future practical and industrial applications. The adsorption kinetic of CO2 in the activated carbons prepared with metallic salt of copper is in good accordance with the intraparticle diffusion model, for which diffusion is the rate-limiting step. The adsorption of CO2 in the prepared activated carbons is favorable from the energy and kinetic point of view, as these accompanied by the presence of wide micro–mesoporosity favor the entry of CO2 into the micropores.

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Water Depollution Using Activated Carbons from Aerogels and Bones

Giraldo

Moreno–Piraján

Fonseca

et al. 2018

Environmental Chemistry for a Sustainable World

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Immersion enthalpy of carbonaceous samples in aqueous solutions of monohydroxilated phenols

Cited by 12 publications

References 16 publications

Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Adsorption of CO₂ on Activated Carbons Prepared by Chemical Activation with Cupric Nitrate

Water Depollution Using Activated Carbons from Aerogels and Bones

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Immersion enthalpy of carbonaceous samples in aqueous solutions of monohydroxilated phenols

Cited by 12 publications

References 16 publications

Interaction between Hydrocarbons C6 and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Interaction between Hydrocarbons C6 and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Adsorption of CO2 on Activated Carbons Prepared by Chemical Activation with Cupric Nitrate

Water Depollution Using Activated Carbons from Aerogels and Bones

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Product

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Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Interaction between Hydrocarbons C₆ and Modified Activated Carbons: Correlation between Adsorption Isotherms and Immersion Enthalpies

Adsorption of CO₂ on Activated Carbons Prepared by Chemical Activation with Cupric Nitrate