Zeolite, cuboidal, crystalline, synthetic, non-fibrous

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Jan. 21, 2000

Deviations:

not specified

GLP compliance:

no

Type of method:

other: measurement of silicon (Si) and aluminium (Al) per ICP-OES, using two soils with different clay, sand and organic carbon content

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

Zeolite, cuboidal, crystalline, synthetic, non-fibrous

EC Number:

930-915-9

Cas Number:

1318-02-1

Molecular formula:

M2/nO • Al2O3 • ySiO2 • wH2O (n is the valency of the cation M, predominantly Na, y can range from 0.64 to 8.8, and w is the number of water molecules (general formula) Na: 1.34 - 24.02%, Al: 2.20 - 39.51%, Si: 15.52 - 68.64% (general composition); additionally, depending on the water quality: Ca, Mg and K might be present below 6%

IUPAC Name:

Zeolite, cuboidal, crystalline, synthetic, non-fibrous

Test material form:

solid: particulate/powder

Remarks:

no surface treatment

Specific details on test material used for the study:

Name: SYLOSIV A4
Batch no.: 1000361205
CAS no.: 1318-02-1
Composition: Zeolite (crystalline Aluminium silicate) 95-100%
Storage: room temperature (20 ± 5 °C)
Expiry date: 31. Jan. 2022
Stability: stable under storage conditions
Appearance: off-white powder
Purity: not applicable, UVCB
Homogeneity: homogeneous
Production date: 01. Dec. 2020
EC no.: 215-283-8 (930-915-9)

Radiolabelling:

no

Study design

Test temperature:

22.5 ± 0.2 °C

Batch equilibrium or other method

Analytical monitoring:

yes

Results and discussion

Adsorption coefficient

Remarks on result:

not determinable

Results: Batch equilibrium or other method

Mass balance (%) at end of adsorption phase

Remarks on result:

not determinable

Any other information on results incl. tables

On day 0, the concentration of silicon in the blank solutions was much higher than the silicon concentration in the diluted test item solution (1.66 mg/L Si). Therefore, the concentration of silicon in the blank solutions on day 0 was 73 % and 84 % of the silicon concentration in the test item solutions with Eurosoil 5 and Lufa 2.2 soils, respectively; and higher than 76 % and 94 % after 24 h and 48 h.

During the test the measured silicon concentration in the blank solutions with soil Lufa 2.2 and Eurosoil 5 has increased incessantly from 7.90 to 12.09 mg/L Si and from 8.95 to 18.82 mg/L Si, respectively, despite the 2 d equilibration phase before start of the test.

After 48 h test duration, the concentration of silicon in Lufa 2.2 and in Eurosoil 5 test item solutions was 0.50 mg/L and 5.02 mg/L after subtraction of the blank solutions, respectively. The value in Eurosoil 5 test item solutions has also increased incessantly during the test. The silicon concentration in Lufa 2.2 solutions has decreased in comparison to the initial value. This is possible due to an insufficient precision of the determination of the initial value (RSD of 93 %). If the first replicate is used in the calculation on day 0 only, the concentration of Si in the test item solutions was nearly the same during the test: 0.49 – 0.52 mg/L. Therefore, no absorption on soils was presumed.

The concentration of aluminium in the blank solutions of Eurosoil samples (92.7 mg/L) was much higher than the aluminium concentration in the diluted test item solution on day 0 (2.13 mg/L Al). Furthermore, after 24 h and 48 h the concentration of aluminium in the test item solutions was lower than in the blank solutions. In comparison to Eurosoil samples, the Lufa blanks solutions showed the concentration of Al 43 µg/L on day 0. A minimal increase of the Al concentrations up to 66 µg/L was observed in the blank solutions during the test. The concentration of Al in the Lufa test item solutions was nearly the same as in the blank solutions. A precipitation of Al was possible occurred after addition of the test item stock solution as the concentration of Al in the diluted stock solution was 2.13 mg/L.

The high difference between the Si and Al concentrations in Lufa 2.2 and in Eurosoil 5 test item solutions each was due to different pH values as the properties of dissolved Si and Al are strongly dependent on the pH value. Furthermore, different Si and Al ions were probably present in the test mixture (obtained from the soil and from the test item). The measured pH values in Eurosoil 5 and in Lufa 2.2 test item solutions were 2.9 and 6.5, respectively. Due to a very high concentration of Si in the blank solutions of both soils and Al in Eurosoil 5 solutions only, the determination was not sufficiently accurate. The concentration of Al in Lufa 2.2 solutions was very low and nearly the same in all solutions during the test.

Therefore, the determination of the adsorption of SYLOSIV A4 on soils is not possible.

Applicant's summary and conclusion

Conclusions:

The determination of the adsorption of SYLOSIV A4 on soils is not possible.

Executive summary:

This study was performed in order to evaluate the adsorption behaviour of SYLOSIV A4 via measurement of silicon (Si) and aluminium (Al) per ICP-OES, using two soils with different clay, sand and organic carbon content.

Preliminary study was performed in order to determine the concentration of silicon and aluminium in the blank value in comparison to the test item solution.