New theoretical expressions for the five adsorption type isotherms classified by BET based on statistical physics treatment

Khalfaoui, Mohamed; Knani, Salah; Hachicha, M.A.; Lamine, Abdelmottaleb Ben

doi:10.1016/s0021-9797(03)00139-5

Cited by 371 publications

(167 citation statements)

References 9 publications

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“…5). Figure 5 shows a behavior of the BET type II adsorption isotherm with the negative concavity, characteristic of nonporous or low porous systems, representing the monolayer formation, in this step high energy demand (Khafaloui et al 2003).…”

Section: Characterization Of Adsorbent Materialsmentioning

confidence: 99%

Removal of Cd(II), Pb(II) and Cr(III) from water using modified residues of Anacardium occidentale L.

et al. 2018

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The pollution of water has been one of the greatest problems faced by the modern society, due to industrialization and urban growth. Rivers, lakes and seas have been continually suffering from the rising concentration of various pollutants, especially toxic elements. This study aimed to evaluate the use of cashew nut shell (Anacardium occidentale) (CNS), after chemical modification with H 2 O 2 , H 2 SO 4 and NaOH, as an new and renewable adsorbent material, for the removal of metals Cd 2+ , Pb 2+ and Cr 3+ in aqueous medium. The adsorbents were characterized by its chemical constitution, structure, infrared spectroscopy, morphology, by means of scanning electron microscopy, determination of the point of zero charge, thermogravimetrical analysis and porosimetry assessments. Tests were conducted to determine the optimal conditions (pH vs. adsorbent mass) for adsorption, by means of multivariate analysis using a central composite design. The adsorption kinetics was evaluated by models of pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion, while adsorption isotherms were linearized by Langmuir, Freundlich and Dubinin-Radushkevich. The effect of initial concentration, temperature and desorption was also performed. The adsorbents exhibited irregular, spongy and heterogeneous structure. FTIR analysis confirms the presence of hydroxyl, aliphatic, phenolic and carboxylic acid groups, which are favorable adsorption characteristics. The pH PZC of adsorbent is 4.35, 2.50 e 6.92, respectively, for CNS H 2 O 2 , H 2 SO 4 and NaOH. The optimum adsorption conditions were as follows: pH 5.0; relation of adsorbent mass/volume of water: 4 g L −1 ; 40 min of contact time for reaching the equilibration. Results suggest the predominance of chemisorption of Cd 2+ and Cr 3+ . Most of biosorbents exhibited good fit by Langmuir and Freundlich, suggesting the occurrence of adsorption on mono-and multilayers. The adsorbents of cashew nut shell exhibited high removal efficiency of Cd, Pb and Cr from waters.

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Section: Characterization Of Adsorbent Materialsmentioning

confidence: 99%

Removal of Cd(II), Pb(II) and Cr(III) from water using modified residues of Anacardium occidentale L.

et al. 2018

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“…S3. The isotherm is type-III with an H4-type hysteresis loop, indicating a macroporous structure mainly caused by the stacking of the PbCrO 4 nanorods [20][21][22]. The BET surface area is 8.50 m 2 g −1 .…”

Section: Resultsmentioning

confidence: 98%

PbCrO4 yellow-pigment nanorods: An efficient and stable visible-light-active photocatalyst for O2 evolution and photodegradation

Zhang

Liu

et al. 2018

Sci. China Mater.

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Here, PbCrO 4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple precipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO 4 nanorods exhibit excellent stability and photocatalytic performance for O 2 evolution from water. The production rate is approximately 314.0 μmol h −1 g −1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PbCrO 4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visiblelight irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO 4 photocatalyst by transforming heavy-metal pollutants Pb(II) and Cr(VI) into a highly efficient O 2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications.

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“…During sorption, the system is considered like an interaction between the absorbate (hydrogen atoms and the absorbent (receptors sites of Mg 50 Ni 45 Ti 5 ). The study of particles exchange between the bulk phase and the absorbed phase requires the use of grand canonical ensemble in statistical physics [30] in order to take account of the variation of particle number during the absorption phenomenon. This analysis follows four distinguished parts.…”

Section: Structure and Morphology Of The As-milled Powdermentioning

confidence: 99%

“…Initially, the hydrogen is considered as a perfect gas [30][31][32] supposing that the mutual interaction between the gaseous hydrogen molecules will be ignored. Usually, below the critical pressure (P=13 bar) and higher than critical temperature (T=33 K), hydrogen is an ideal gas [31,33].…”

Section: Characterization Through Statistical Physicsmentioning

confidence: 99%

Morphologic, Structural, Steric, Energetic and Thermodynamic Studies of the Mechanical Alloy Mg50Ni45Ti5 for Hydrogen Storage

Mechi¹,

Khemis²,

Dhaou³

et al. 2017

J Phys Chem Biophys

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New theoretical expressions for the five adsorption type isotherms classified by BET based on statistical physics treatment

Cited by 371 publications

References 9 publications

Removal of Cd(II), Pb(II) and Cr(III) from water using modified residues of Anacardium occidentale L.

Removal of Cd(II), Pb(II) and Cr(III) from water using modified residues of Anacardium occidentale L.

PbCrO4 yellow-pigment nanorods: An efficient and stable visible-light-active photocatalyst for O2 evolution and photodegradation

Morphologic, Structural, Steric, Energetic and Thermodynamic Studies of the Mechanical Alloy Mg50Ni45Ti5 for Hydrogen Storage

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