MoVNbTe mixed oxide

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

Adsorption / Desorption using a Batch Equilibrium Method according to the Guideline OECD106
The batch equilibrium method uses soil suspensions in 0.01 M calcium chloride spiked with a chemical to investigate its adsorption and desorption behavior. Soils differing e. g. in the organic carbon content, clay content, soil texture and pH will be used for this purpose to evaluate the impact of the soil properties on the adsorption and desorption behavior of a chemical. The soil suspensions are agitated by an appropriate device (e. g. horizontal shaker) for a defined period and the distribution of the chemical between the aqueous phase and soil is determined by chemical analysis for the deduction of the study endpoints.

Suitability of the Guideline OECD106 for the Determination of the Adsorption / Desorption Behavior of MoVTeNbO-Mixed Oxide
The solubility of MoVTeNbO-Mixed Oxide in ultrapure water and 0.01 M calcium chloride has been investigated by determination ob the molybdenum conentration in water.

Method
Preparation
2mL ultrapure water respectively 0.01 M calcium chloride were added to 2.5 mg MoVTeNbO-Mixed Oxide in a 4mL glas vial. The nominal concentration was 1.25 g test item / L or 524 mg Mo / L for the saturated solution. After 1 week the Molybdän-content was determined.

Analytical Method
Analytical quantification of the test item was carried out via photometer. A standard test kit provided by Macherey-Nagel with a quantification range from 1.0 to 40.0 mg Mo(VI) / L was used.

Results
The measured concentrations were 3.5 mg Mo(VI) / L for ultrapure water and 3.7 mg Mo(VI) / L for 0.01 M calcium chloride. On average ths concentration corresponds to 8.6 mg test item / L or less than 0.7 % of the saturated solution.

Conclusion
An adsorption / desorption study according to the guideline OECD106 with the test item is not feasible due to its low water solubility of the whole test item and the instability of the substance during the solution process. During the solution process, the test item dissociate in the ions of the test item molybdenum, vanadium, tellurium and niobium. For the molecule no solution process without degradation into the single ions is possible. Furthermore the concentration of niobium in the water phase will be in lower ppt and will not be feasible for the adsorption / desorption study.

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Year:

2022

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)