Relación entre la entalpía de inmersión de monolitos de carbon activado y parametros texturales

Vargas, Diana; Gutiérrez, Liliana Giraldo; Moreno, Juan Carlos

doi:10.1590/s0100-40422011000200005

Cited by 9 publications

(2 citation statements)

References 10 publications

(14 reference statements)

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“…The immersion of enthalpies in water are between −28.8 and 49.1 J g –1 , in benzene between −117.0 and −55.5 J g –1 , and in dichloromethane between −117.3 and −50.6 J g –1 . These results are comparable with those from other investigations that employed similar methodologies and the use of lignocellulosic precursors from agro-industrial waste in the production of activated carbons. − …”

Section: Resultssupporting

confidence: 88%

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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Section: Resultssupporting

confidence: 88%

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

2020

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“…A characterization technique of solid-gas or solid-liquid interaction is immersion calorimetry, which allows calculating the heat quantity generated when the two phases come in contact, which is characteristic of a specific adsorption system in determined temperature and pressure conditions [9].…”

Section: Introductionmentioning

confidence: 99%

Ni(II) and Cd(II) Simple and Competitive Adsorption on Activated Carbon Oxidized. Influence of the Oxidant Agents HO and NaClO

Sánchez¹,

Rodríguez-Estupiñán²,

Giraldo³

et al. 2015

TOMSJ

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In this study, granular activated carbon, GAC, was modified by oxidation with HO and NaClO aqueous solutions and heat treatment at 900°C. The N adsorption isotherms at − 196°C and SEM and FTIR results were used to characterize the properties of the prepared ACs. Textural parameters such as BET surface area and pore volumes were assessed by gas adsorption. The BET surface area values of solids were between 687 and 876 m2g-1. Additionally, immersion enthalpies of activated carbons in benzene, water, hydrochloric acid and sodium hydroxide solutions and Ni(II) and Cd(II) solutions of 500 mgL were determined, with values between 32 and 145 Jg-1. Ni(II) and Cd(II) adsorption isotherms were determined at pH 6 on activated carbons and competitive adsorption tests were realized between the two ions. The results show that in the tests carried out, the adsorption capacity decreased when the content of chemical groups on the surface also decreased. Finally, the experimental results of adsorption from the solution were adjusted to the Langmuir and Freundlich models and the first model was found to be better. With maximum adsorption capacities, the values for Ni(II) were between 3.99 and 64.9 mgg-1 and for Cd(II) were between 2.61 and 55.2 mgg-1. The values of the competitive adsorption ions present in the solution, Ni(II) and Cd(II), in the activated carbons, decreased compared to those obtained in the simple adsorption, indicating the effect of the an ion competitive presence in adsorption another.

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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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Relación entre la entalpía de inmersión de monolitos de carbon activado y parametros texturales

Cited by 9 publications

References 10 publications

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

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

Ni(II) and Cd(II) Simple and Competitive Adsorption on Activated Carbon Oxidized. Influence of the Oxidant Agents HO and NaClO

Water Depollution Using Activated Carbons from Aerogels and Bones

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Relación entre la entalpía de inmersión de monolitos de carbon activado y parametros texturales

Cited by 9 publications

References 10 publications

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

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

Ni(II) and Cd(II) Simple and Competitive Adsorption on Activated Carbon Oxidized. Influence of the Oxidant Agents HO and NaClO

Water Depollution Using Activated Carbons from Aerogels and Bones

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

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