General Cluster Sorption Isotherm

Buttersack, Christoph

doi:10.1016/j.micromeso.2021.110909

Cited by 31 publications

(23 citation statements)

References 58 publications

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“…Although Zn-mI-BDC exhibited a N 2 adsorption–desorption isotherm of type I, a hysteresis loop was observed which is typical for a hierarchical microporous and mesoporous material ( Figure 2 a). 29 …”

Section: Resultsmentioning

confidence: 99%

Mixed-Ligand Strategy for the Creation of Hierarchical Porous ZIF-8 for Enhanced Adsorption of Copper Ions

et al. 2022

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The adsorption of heavy metals using metal–organic framework-based adsorption technology has been pointed out as a promising technique for the removal of these toxic elements from water. However, their adsorption capacity needs to be enhanced. Thus, the current work reports the effect of using a mixed-ligand strategy on the MOF framework and its effect on the removal of copper ions from water by adding terephthalic acid (BDC) linker to the ZIF-8precursors (2-methylimidazole (mI) and Zn 2+ ) under solvothermal synthesis, leading to the formation of a hierarchical microporous mesoporous MOF, named Zn-mI-BDC, which was characterized by SEM, EDX, XRD, TGA, BET, and FTIR. As a result, all of these techniques revealed that the addition of a controlled amount of BDC did not alter the crystallinity of ZIF-8, resulting in the creation of a pore size of 4.2 nm. The new hierarchical porous MOF was tested for the adsorption of copper and exhibited an enhanced adsorption capacity compared to pristine ZIF-8 and many other standard adsorbents. The adsorption isotherm matched well with the Langmuir isotherm model, suggesting that the adsorption process chemisorption had a dominant role in the adsorption of Cu 2+ species. Therefore, the current work is considered as an important step toward the use of a mixed-ligand strategy in enhancing the adsorption capacity of heavy metals using MOF materials.

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Section: Resultsmentioning

confidence: 99%

Mixed-Ligand Strategy for the Creation of Hierarchical Porous ZIF-8 for Enhanced Adsorption of Copper Ions

et al. 2022

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“…A good description of the amount adsorbed for these vapors on nonporous substrates is essential for understanding the interaction potentials and for better characterization of porous substrates, , like ordered mesoporous materials ,,− (OMM). Such a thermodynamic isotherm, which is valid in the entire equilibrium range, is also needed to compare the results of the adsorption analysis using molecular dynamics, − performing biological studies, and analyzing the microporosity of materials like activated carbon and hard carbon . A good description of the Ar thermodynamic isotherm is also needed for adsorption studies where N 2 gas cannot be used, such as for analysis on a lithium adsorbent …”

Section: Discussionmentioning

confidence: 99%

Specific Surface Area of Nanopowders from Argon Adsorption at 77 and 87 K: Zeta Adsorption Isotherm Approach

Narayanaswamy

Ward

2021

J. Phys. Chem. C

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The surface characterization of nanopowders is widely attempted by both N2 and Ar vapor adsorption methods. They are used as complementary probe molecules because of their similarities and certain differences. However, the respective reported analyses, using the Brunauer–Emmett–Teller method, suffer from inconsistencies between the determined values of the specific surface areas, A s. We examine this issue by using the zeta adsorption isotherm approach on the reported data for both vapors on two different samples from the same batch of a nanopowder material. By assuming the equivalence of the A s determined by both of the vapors, we obtain the average occupied area of an adsorbed argon atom, σA(Ar), on silica and carbon black at the solid- and liquid-state temperatures of 77 and 87 K, respectively. We then examine the determined value of σA(Ar) by obtaining A s for other samples of the same material with varying specific areas. By transforming the adsorption data from mass-specific to area-specific, the respective thermodynamic isotherms, n SV, of Ar vapor adsorbing on silica and carbon black are obtained. The determined n SV are then used with the Gibbs adsorption equation to determine the solid surface energy, γS0, and solid–vapor interface energy, γSV, for both substrates. The obtained γSV(x V) on both substrates is used to interpret the phase transition state of the Ar adsorbate at 77 K. The determined thermodynamic isotherms for Ar and N2 vapors are further used in a comparative study to show that the Ar vapor adsorption is negligibly affected by the change in silanol concentration on the silica surface in contrast with N2 vapor adsorption.

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“…Recently, an alternative theoretical isotherm modeling approach has been presented where the intuitive imagination of a layer-by-layer adsorption is replaced by the formation of clusters which are isolated from each other at low but merge at higher degrees of coverage. 14 The model, called general cluster sorption isotherm (GCSI), has been successfully applied to experimental high resolution sorption isotherms of type II and IV. 13,14 Theoretically, it may be conceived as a general extension of the original BET approach.…”

Section: Introductionmentioning

confidence: 99%

“…14 The model, called general cluster sorption isotherm (GCSI), has been successfully applied to experimental high resolution sorption isotherms of type II and IV. 13,14 Theoretically, it may be conceived as a general extension of the original BET approach. 1 Since the clusters were thought to be flexible without a preferential orientation, this new isotherm was assumed to be unsuitable for getting an information on the surface area.…”

Section: Introductionmentioning

confidence: 99%