Interaction of some organophosphorus pesticides with vermiculite

Sánchez‐Camazano, M.; Sánchez-Martín, María J.

doi:10.1016/0169-1317(87)90005-6

Cited by 3 publications

(2 citation statements)

References 10 publications

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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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Section: Introductionmentioning

confidence: 99%

Adsorption and Decomposition of Dimethyl Methylphosphonate on Metal Oxides

1997

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“…Porous materials, especially the natural porous minerals, have attracted considerable attentions due to their wide applications in catalysis, adsorption, separation, and ion exchange, etc [1][2][3][4][5][6][7][8][9][10][11]. The development of hierarchically ordered structures at multiple length scales has attracted much interest over the past few years [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Various Morphology of Hierarchical Pore-Structured Compound: MCM-41/Diatomite and its Adsorption Behavior for Methylene Blue

Xia

Jiang

2013

AMR

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Hierarchical porous materials attract considerable attentions due to their interesting structures and superior adsorption capabilities. In this work, a novel macro- and meso-porous hierarchical material, MCM-41/diatomite, has successfully been synthesized from natural diatomite and tetraethoxysilane by basic hydrothermal method. Nitrogen adsorption/desorption isotherms, low angle XRD and SEM analysis were carried out to character the multiple porous structure and morphology of MCM-41/diatomite. The resultant compound displayed high specific surface area (862~1041 m2/g) and macro-meso-porous hierarchical structure. The morphology of MCM-41/diatomite could be various, such as worm-like, grape-like, flocky, and acaleph-like, due to different ratio between TEOS, PEG, and NaOH. Moreover, the results of adsorption experiments show that some of the resultant MCM-41/diatomite display stronger adsorption capabilities than simply mesoporous MCM-41, due to the macro-meso-porous hierarchical structure, which would further extend the application of MCM-41/diatomite as adsorbent and catalyst support.

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