Vapor-phase sorption of p-xylene on cobalt- and copper-exchanged SAz-1 montmorillonite

Johnston, Cliff T.; Tipton, T.; Trabue, Steven; Erickson, C.; Stone, Daniel A.

doi:10.1021/es00026a021

Cited by 27 publications

(14 citation statements)

References 21 publications

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“…The authors of that paper indicated that the sorption processes would not be completed instantaneously because of the limitation of the diffusion of the sorbate into the sorbent matrix. 23,2004 Y.-H. Shih and S.-C. Wu on smectites and indicated that the sorption of this aromatic compound by smectites was a physical phenomenon. Hundal et al [35] studied the sorption of phenanthrene 2066 Environ.…”

Section: Irreversible Sorptionmentioning

confidence: 99%

Kinetics of toluene sorption and desorption in Ca‐ and Cu‐montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidity

Shih

2004

Enviro Toxic and Chemistry

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Clays in soils or groundwater aquifer materials play roles in the sorption of organic pollutants. The intrinsic sorption kinetics of toluene in dry and humid clay films was investigated by tracking the change of infrared absorbance. Under the humid condition, similar toluene-sorbed intensities were found in Ca- and Cu-montmorillonites. However, a higher intensity of sorbed toluene was found in the Cu-form than in the Ca-form under the dry condition, which indicates a stronger interaction occurring in dry Cu-montmorillonite. The general time scale of sorption of toluene on clays is around 100 s. In both forms of montmorillonite, some portion of toluene was desorbed at an extremely slow rate under the dry condition. Some newly identified peaks were persistent against desorption from montmorillonites, suggesting the existence of irreversibly sorbed species and the possibility of toluene transformation occurring in clay systems.

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Section: Irreversible Sorptionmentioning

confidence: 99%

Kinetics of toluene sorption and desorption in Ca‐ and Cu‐montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidity

Shih

2004

Enviro Toxic and Chemistry

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“…Although the experiments performed under short-term and extremely dry conditions using modified copper-exchanged clay have shown chemical transformation of organic pollutants [12][13][14], the long-term observation for the calcium-exchanged clay under both high and low RH conditions has not been reported before.…”

Section: Discussionmentioning

confidence: 94%

“…Sorption of arenes, like anisole, xylene, toluene, and benzene, onto transition-metal-, usually Cu-, exchanged montmorillonite and smectite under P 2 O 5 -dried conditions [10,11] or conditions where both sorbent and sorbate were refluxed in n-hexane for up to 48 h [12,13] resulted in the formation of irreversibly chemisorbed products. Chemisorption of p-xylene on self-supporting Cu-exchanged montmorillonite film has been identified with Fourier transform infrared/ultraviolet-visible spectra by Johnston et al [14]. The authors suggested that the directly coordinated water on the copper must have been replaced by a xylene molecule so the ligand position of the interlamellar copper might have been exposed to the electrons of a benzene ring.…”

Section: Introductionmentioning

confidence: 99%

Infrared investigation of the sequestration of toluene vapor on clay minerals

Chang

Chen

et al. 2003

Enviro Toxic and Chemistry

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The Ca-exchanged clays were used to investigate the sorption of toluene under both high and low relative humidity conditions. According to the observed rates of sorption and desorption and the Fourier transform infrared (FTIR) spectra of sorbed toluene, the sorbate molecules on clays can be divided into three categories: labile (gaslike) phase, slow sorption (liquidlike) phase, and resistant-to-desorption phase with sorption/desorption time scales of less than 30 min, several hours, and several weeks, respectively. Aging changed the spectroscopic characteristics of the sorbed sorbates and contributed to the irreversibility of the sorption under both high and low relative humidity. Irreversibly sorbed portions of the sorbates and new characteristic peaks identified with FTIR spectrometry suggest the existence of chemical transformation of sorbed species under both high and low relative humidity conditions. It is suggested that the clay minerals, acting as catalysts, may contribute to abiotic natural attenuation of volatile organic aromatic hydrocarbons in soils.

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“…IR Analysis: Fate of TPB Infrared spectroscopy has previously been shown to be a powerful tool for studying reactions at surface acid sites using a variety of surface-sorbed probe molecules (12,13,21,22). For example, the protonation of NH 3 to NH 4 + when adsorbed at Bronsted sites can be clearly distinguished from NH 3 retained at Lewis sites using IR (12).…”

mentioning

confidence: 99%

“…The application of IR spectroscopy to organic sorbates has been primarily limited to gas-phase adsorption kinetics and gas-phase catalysis (21). The usefulness of IR for investigating sorption/desorption processes in situ, has been demonstrated for the selectivity of conformer adsorption at mineral surfaces (22).…”

mentioning

confidence: 99%

Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

Hunter

Gates

Bertsch

et al. 1999

ACS Symposium Series

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The surface catalyzed redox reactivity of an organoboron probe molecule (tetraphenylboron, or TPB) with fully hydrated clay mineral surfaces is described wherein one or both of two degradation pathways can occur. Attenuated total reflectance Fourier transform infrared (ATR-IR) spectroscopy can quantitatively measure, in situ, both acid hydrolytic and oxidative degradation of TPB as controlled by the exchange cation identity and the structural octahedral Fe content of the clay mineral. Oxidation of TPB at smectite surfaces is directly attributable to octahedral Fe(III) in the clay structure.The concomitant reduction of Fe(III) during TPB oxidation can be analytically measured by X-ray absorption near edge structure (XANES) spectroscopy. The resultant distortion of the clay mineral structure during the reduction of structural Fe could be probed directly by extended X-ray absorption fine structure (EXAFS) spectroscopy. The lack of evidence for clay mineral dissolution during the reaction with TPB permits defining the clay as a catalyst. The combination of these three in situ spectroscopic techniques to measure the reaction in real time, provides powerful insight into the reactivity of clay mineral surfaces.

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Vapor-phase sorption of p-xylene on cobalt- and copper-exchanged SAz-1 montmorillonite

Cited by 27 publications

References 21 publications

Kinetics of toluene sorption and desorption in Ca‐ and Cu‐montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidity

Kinetics of toluene sorption and desorption in Ca‐ and Cu‐montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidity

Infrared investigation of the sequestration of toluene vapor on clay minerals

Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

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