Interactions of Alachlor With Homoionic Montmorillonites

Bosetto, M.; Arfaioli, Paola; Fusi, P.

doi:10.1097/00010694-199302000-00004

Cited by 44 publications

(37 citation statements)

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“…Such an interaction is expected to lower the force constant of the carbonyl group and decrease the frequency value to a greater extent the higher the polarizing force. A similar behavior was already observed for the adsorption of a number of pesticides on clays (Micera et al 1988, Pusino et al 1989, Bosetto et al 1993.…”

Section: Adsorption From Organic Solventsupporting

confidence: 81%

Adsorption Mechanisms of Imazamethabenz-Methyl on Homoionic Montmorillonite

Pusino

Gelsomino

Gessa

1995

Clays and clay miner.

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Almtraet --The adsorption of the herbicide imazamethabenz-methyl, a mixture of the two isomers methyl (_+)-2-[4,5-dihydro-4-methyl-4-(1 -methylethyl)-5-oxo-1H-imidazol-2-yl]-4-methylbenzoate (para isomer) and methyl (+_)-2-[4,5-dihydro-4-methyl-4-(1 -methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methylbenzoate (meta isomer), from water onto AP +-, Fe 3+-, Ca 2+ -, K +-and Na+-montmorillonite was studied by analytical (HPLC) methods. The adsorption from an organic solvent was also investigated by spectroscopic (IR) and X-ray diffraction measurements. It was observed that, depending on the acidic properties of the exchangeable cations, two different mechanisms may take #ace. The first one, acting on Fe a+-and AI a+-clays, involves the protonation of the more basic nitrogen atom ofimidazolinone ring of the herbicide because of a proton transfer from the acidic metal-bound water, followed by adsorption on the clay surfaces. In this case, the clay surfaces have greater affinity for the meta than the para isomer, due to the extra-stabilization of the meta protonated form by resonance. The second mechanism, taking place on Ca 2 § -, K +-and Na +-clays, is hydrogen-bond formation between the ester carbonyl group of the herbicide and hydration water metal ions and is not affected by the structure of the isomers.

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Section: Adsorption From Organic Solventsupporting

confidence: 81%

Adsorption Mechanisms of Imazamethabenz-Methyl on Homoionic Montmorillonite

Pusino

Gelsomino

Gessa

1995

Clays and clay miner.

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“…Apparently, Ca 2+ exerts such a strong influence over the position and orientation of hydrating water molecules within these simulations that their ability to form secondary H-bonds with organic molecules is hampered. Experimental data including the removal of significant levels of clay-adsorbed organic molecules through washes with water (Theng, 1974(Theng, , 1979Theng and Scharpenseel, 1975;Mirabella et al, 1996), the trend observed in montmorillonite suspensions of increasing organic adsorption with increasing cation charge to radius ratio (Theng and Scharpenseel, 1975), and distinctive shifts, or lack thereof, in infrared signals (Theng, 1974(Theng, , 1979Bosetto et al, 1994), are interpreted to be evidence of adsorption through water bridges. None of these experimental observations provides compelling evidence that the water molecule between cation and organic is H-bonded to the organic functional group.…”

Section: Cation and Water Bridging Interactionsmentioning

confidence: 99%

Molecular simulation of humic substance–Ca-montmorillonite complexes

Sutton

Sposito

2006

Geochimica et Cosmochimica Acta

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“…This phenomenon was attributed to the aromatic nucleus of LAS being too large (ϳ35 Å ) to enter the interlayers of an expanded montmorillonite clay (ϳ10-20 Å ) [7], as was observed for 2,4-dichlorophenoxyacetic acid sorption and biodegradation in the presence of montmorillonite [25]. Another chemical with an aromatic nucleus (alachlor) was also unable to enter the interlayers of montmorillonite when the clay had been saturated with monovalent cations [26]. Most of the other chemicals, although of equal or greater mass, did not have a moiety with a radius as large as the aromatic ring and therefore could partition into the interlayer spaces, which would result in a pool of the chemical that would be unavailable for microbial degradation.…”

Section: Influence Of the Different Soil Constituents On Biodegradationmentioning

confidence: 99%

Microbial mineralization of organic compounds in an acidic agricultural soil: Effects of preadsorption to various soil constituents

Knaebel

Vestal

Federle

et al. 1996

Enviro Toxic and Chemistry

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Abstract-This study investigated the interactions between organic chemicals and components of the soil matrix and their effects on subsequent microbial mineralization kinetics. Five 14 C-labeled chemicals (anionic, cationic, and nonionic surfactants) were aseptically sorbed to montmorillonite, kaolinite, illite, sand, humic acids, and fulvic acids. Small amounts of these sorbed chemicals were dosed to an acidic, sludge-amended agricultural soil (Rossmoyne) to a final added chemical concentration of 50 ng g Ϫ1 . Controls received the same final added concentration of the chemicals in water. The ratio of sorbed chemical to soil was kept low to minimize changes to the soil mineralogy, chemistry, and microbiology. Microbial mineralization of the chemicals to 14 CO 2 was measured over a period of 60 to 70 d, and the data were fitted to first-order and 3/2-order mineralization models. Association with the soil constituents inhibited the mineralization of the chemicals in the following rank (from least to greatest effect): controls ഠ sand Ͻ kaolinite Ͻ illite Ͻ montmorillonite ഠ humic acids Ͻ fulvic acids. These experiments demonstrated that interactions with some soil constituents (kaolinite, illite, and sand) had little effect on the microbial metabolism of these chemicals, while montmorillonite, humic acids, and especially fulvic acids significantly decreased the bioavailability of the chemicals to the microbial community. The first group of soil constituents had little influence on the mineralization kinetic parameters, whereas the latter significantly reduced at least one of the parameter estimates. The parent soil, possibly via interactions with its mineral surfaces, also had effects on the degradation of the chemicals, since soil microbial biomass and physiological activity were not correlated with any of the mineralization kinetic parameter estimates. These experiments demonstrate that the environmental form of a chemical has a significant influence on its eventual microbial metabolism and is an important parameter to consider when investigating the fate of chemicals in soil environments.

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Interactions of Alachlor With Homoionic Montmorillonites

Cited by 44 publications

References 0 publications

Adsorption Mechanisms of Imazamethabenz-Methyl on Homoionic Montmorillonite

Adsorption Mechanisms of Imazamethabenz-Methyl on Homoionic Montmorillonite

Molecular simulation of humic substance–Ca-montmorillonite complexes

Microbial mineralization of organic compounds in an acidic agricultural soil: Effects of preadsorption to various soil constituents

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