Effect of organic cosolvents on adsorption of organophosphorus pesticides by soils

Adsorption and desorption processes of the organophosphorus pesticides, dimethoate and fenthion, onto three Greek agricultural soils

“…The use of an organic solvent (carrier) is recognised as being essential in studies dealing with the behaviour of organic molecules in aqueous systems [23]. Furthermore several authors in published literature propose the introduction of co-solvents in soil-water systems, because this way a significant increase in the solubility of substances can be achieved [24][25][26]. The use of an appropriate carrier solvent is advocated especially for the more hydrophobic compounds (log K ow 44), because it greatly facilitates batch and column experimentation and minimises experimental artifacts.…”

Co-solvent effects on the adsorption of carbofuran by two Indian soils

“…The co‐solvent theory16 was used to describe the adsorption of hydrophobic organic compounds to soil from binary and mixed‐solvent systems. The theory has been applied to the adsorption of organic compounds having moderate and intermediate hydrophobicity 17–20, 22, 23. This theory is expressed by the equation: where f S is the volume fraction of co‐solvent, and K mi (mol g −1 ) and K wi (mol g −1 ) are the mole‐based partition coefficients of water‐solvent mixtures and solvent‐free water, respectively.…”

“…Thus it is necessary to characterize pesticide adsorption by soils, not only from aqueous solution but also from mixed aqueous‐organic solvents. Only a few experimental studies to date have focused on pesticide adsorption by soils from organic solvents and solvent mixtures 16–20. Most of the current data in the literature deal with adsorption of poorly water‐soluble, hydrophobic pesticides from mixed solvents, while carbofuran (2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl methylcarbamate, Fig 1) which represents an important group of pesticides, has been little investigated.…”

Sorption of the Pesticide Endosulphan on Two Indian Soils

“…However, in some disposal operations mixtures of chemical waste which are miscible in water reduce the adsorption. Recently, several workers (16)(17)(18) have focused on adsorption of certain pesticides from nonaqueous solvents and solvent mixtures but information of this type is not available in the literature for endosulphan adsorption by soil. In this research we created an adsorption system consisting of a liquid phase of water with an organic solvent, soil, and endosulphan as the test solute to determine the influence of organic solvents methanol and acetone on endosulphan adsorption as measured by the batch equilibrium method and the applicability of the cosolvent theory proposed by Rao et al in 1985 (19) was evaluated.…”