Comparison of sample preparation methods for the Fourier-transform infrared analysis of an organo-clay mineral sorption mechanism

Bowen, John M.; Compton, Senja V.; Blanche, M. Sterling

doi:10.1021/ac00193a009

Cited by 17 publications

(10 citation statements)

References 11 publications

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“…It is interesting that almost the same magnitude of shift was seen comparing DMMP on diamond powder (1243 cm -1 ) to DMMP on Ca-montmorillonite (1210 cm -1 ) . A similar PO frequency shift was observed by Klabunde et al ,, as a consequence of the interaction of DMMP with the surface sites of magnesia.…”

Section: Discussionsupporting

confidence: 73%

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂

2000

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By using Fourier transform infrared spectroscopy (FTIR) we have witnessed the sequential steps of surface diffusion, weak chemical bonding, and decomposition of dimethyl methylphosphonate (DMMP) on TiO2 powder. At temperature lower than ∼160 K, DMMP condenses as an ice layer on the outer surface of the TiO2 sample. In the temperature range 160− 200 K, diffusion into the TiO2 interior occurs and hydrogen bonding of DMMP to isolated TiOH groups is observed. In addition, bonding to Lewis acid sites occurs. Above 214 K, cleavage of P−OCH3 groups takes place, with the production of Ti−OCH3 surface species and this is accompanied by the consumption of surface hydroxyl groups. A reduction of P−O bond order then occurs as adsorbed phosphonate species are formed.

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Section: Discussionsupporting

confidence: 73%

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂

2000

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“…Other investigators have studied the interaction of DMMP with clays, in the hope of gaining insight into the adsorption of pesticides in soils. − Bowen and co-workers 22,23 used infrared diffuse reflectance spectroscopy and infrared photoacoustic methods to study the adsorption and decomposition of DMMP on montmorillonite and calcium montmorillonite clay. They observed a small shift to lower frequency (−6 cm -1 ) of the PO stretching vibration when the DMMP was adsorbed on montmorillonite and a larger downward shift (−21 cm -1 ) when DMMP was adsorbed on calcium montmorillonite.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Decomposition of Dimethyl Methylphosphonate on Metal Oxides

1997

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The adsorption and decomposition of dimethyl methylphosphonate (DMMP) have been examined on four different metal oxide surfaces: aluminum oxide, magnesium oxide, lanthanum oxide, and iron oxide. Aluminum, magnesium, and lanthanum oxides are observed to behave in much the same way, with initial binding of the PO species to the surface at an acid site, followed by stepwise elimination of the methoxy groups, beginning at temperatures as low as 50 °C, which combine with surface hydrogens to yield methanol that evolves from the surface. The final product observed for these oxides is a surface-bound methylphosphonate, with the P−CH3 bond intact, which is resistant to further oxidation even in the presence of 70 Torr of oxygen at 300−400 °C. Adsorption on iron oxide yields a different sequence of events, with the initial adsorption occurring again with the PO moiety binding to an acid site, although there is some indication of the formation of a second type of surface complex. The primary interaction on iron oxide appears to be much stronger than with the other oxides, and probably involves the unidentate coordination of the DMMP to a Lewis acid site on the surface. Nonselective elimination of both the methoxy and the phosphorus-bound methyl groups begins only after heating above 200 °C, but occurs with total elimination of the methyl and methoxy groups observed after heating above 300 °C in vacuum. The ease with which iron oxide cleaves the P−CH3 bond is attributed to the availability of multiple oxidation states to the iron atom. Participation of the Fe(III)/Fe(II) redox couple in the reaction provides a low-energy path for oxidative cleavage of the P−CH3 bond. The other oxide surfaces cannot provide a similar path, and on these surfaces the P−CH3 bond is resistant to cleavage. The use of infrared diffuse reflectance techniques, observing, in particular, the methyl stretch region of the infrared spectrum, has allowed the almost complete characterization of the decomposition processes which occur after DMMP adsorbs on aluminum oxide, magnesium oxide, lanthanum oxide, and iron oxide.

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“…Knowing that many toxic pesticides may exists in soil, some investigators have also studied the adsorption and interaction of DMMP with clays, such as montmorillonite and calcium montmorillonite clay . It was found that DMMP can directly combine to the cations in the montmorillonite clay, rather than through hydration of intermediate water …”

Section: Other Nanomaterials For Mimicking Phosphatases and Nucleasesmentioning

confidence: 99%

From DNA to Nerve Agents – The Biomimetic Catalysts for the Hydrolysis of Phosphate Esters

et al. 2020

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The phosphate ester bonds are widely present in living organisms and in the environment. From the nucleic acids to the sparingly dispersed pesticides and chemical warfare residues, the phosphoester bond's stability against hydrolysis can be extremely high or exceptionally low. Recently, the enzyme-mimicking nanomaterials, namely 'nanozyme', have been explored for their activities in hydrolytically cleaving DNA, organophosphate and their analogues. Herein in a broad perspective these nanomaterials were summarized and compared with a view to reproducing the catalysis efficiency and selectivity of natural phosphatases and nucleases. The development of biomimetic inorganic materials would not only provide potential nanomedicine for future gene editing, but also offer alternative solutions to the environmentally friendly treatment of pesticide residues and chemical warfare stockpiles.

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Comparison of sample preparation methods for the Fourier-transform infrared analysis of an organo-clay mineral sorption mechanism

Cited by 17 publications

References 11 publications

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂

Adsorption and Decomposition of Dimethyl Methylphosphonate on Metal Oxides

From DNA to Nerve Agents – The Biomimetic Catalysts for the Hydrolysis of Phosphate Esters

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Comparison of sample preparation methods for the Fourier-transform infrared analysis of an organo-clay mineral sorption mechanism

Cited by 17 publications

References 11 publications

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO2

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO2

Adsorption and Decomposition of Dimethyl Methylphosphonate on Metal Oxides

From DNA to Nerve Agents – The Biomimetic Catalysts for the Hydrolysis of Phosphate Esters

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Product

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Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂

Adsorption and Decomposition of Dimethyl Methylphosphonate on TiO₂