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Adsorption / desorption

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1-Ethyl-3 Methyl lmidazolium Ethylsulfate can be considered slightly mobile in Speyer 2.1 and Speyer 2.2 soil, and immobile in Speyer 6S soil, according to the classification scheme by Mensink. Mean Kom ads values were 40 cm3/g (Speyer 2.1 soil), 30 cm3/g (Speyer 2.2 soil) and 662 cm3/g (Speyer 6S soil).
The adsorption coefficient (Koc) of 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE (EMIM ES) at 35°C was determined to be > 4.3 * 10 5 (log Koc> 5.63) for the cationic 1-ETHYL- 3-METHYL IMIDAZOLIUM part and < 2.1 * 10 1 (log Koc < 1.32) for the anionic ETHYLSULFATE part and for an impurity.

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The adsorption behaviour of 1-Ethyl-3 Methyl lmidazolium Ethylsulfate in soils was studied in three soils: Speyer 2.1 [2.09% organic matter (OM), sand], Speyer 2.2 [3.9% OM, loamy sand] and Speyer 6S [3.3 % OM, sandy clay]. Adsorption and desorption were studied using the method as described in the OECD guideline for the testing of Chemicals No.106 (Screening Version): "Adsorption/Desorption", adopted May 12,1981. Adsorption and desorption kinetics were determined at an initial test substance concentration of approximately 10 mg/L. All adsorption-desorption experiments were carried out at 20°C ± 2°C. 1-Ethyl-3 Methyl lmidazolium Ethylsulfate can be considered slightly mobile in Speyer 2.1 and Speyer 2.2 soil, and immobile in Speyer 6S soil, according to the classification scheme by Mensink. Mean Kom ads values were 40 cm3/g (Speyer 2.1 soil), 30 cm3/g (Speyer 2.2 soil) and 662 cm3/g (Speyer 6S soil).

The estimation of the adsorption coefficient (Koc) of the test substance in Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC) was based on the following guideline: Organization for Economic Co-operation and Development (OECD), OECD Guideline for Testing of Chemicals, Proposal for a new guideline 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)", January 2001. According to this OECD guideline, the estimation of the adsorption coefficient (Koc) for test substances that are ionized for at least 10% within pH 55 to 7.5, should be performed with both the ionized and non-ionized form. 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE is a salt consisting of a cationic 1-ETHYL-3-METHYL IMIDAZOLIUM part and an anionic ETHYLSULFATE part. Therefore, the test substance is ionized at each pH value. From this, it was decided to perform the HPLC method without buffering of the mobile phase. The adsorption coefficient (Koc) of 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE at 35°C was determined to be > 4.3 * 10 5 (log Koc> 5.63) for the cationic 1-ETHYL- 3-METHYL IMIDAZOLIUM part and < 2.1 * 10 1 (log Koc < 1.32) for the anionic ETHYLSULFATE part and for an impurity.