lithium nickel dioxide

Water solubility

Administrative data

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

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:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Series on Testing and Assessment No. 29 (23-Jul-2001): Guidance document on transformation/dissolution of metals and metal compounds in aqueous media

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

Lithium; oxido(oxo)nickel

Cas Number:

12031-65-1

Molecular formula:

LiNiO2

IUPAC Name:

Lithium; oxido(oxo)nickel

Test material form:

solid

Results and discussion

Solubility of metal ions in aqueous media

Solubility of metal ions in aqueous media 1

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

26.4 µg/L

Element analysed:

Lithium

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C; The pH in method blank media as well as in test item loaded samples was in the range of 6.0 - 6.2 over 28 days of testing with the loading of 1 mg/L.

Solubility of metal ions in aqueous media 2

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

119 µg/L

Element analysed:

Lithium

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C; The pH value for the loading of 10 mg/L increased from 6.1 to a maximum of 6.4.

Solubility of metal ions in aqueous media 3

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

1 976 µg/L

Element analysed:

Lithium

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C; In media with the loading of 100 mg/L the pH value increased from 6.0 to 7.2.

Solubility of metal ions in aqueous media 4

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

51.7 µg/L

Element analysed:

Nickel

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C; The pH in method blank media as well as in test item loaded samples was in the range of 6.0 - 6.2 over 28 days of testing with the loading of 1 mg/L.

Solubility of metal ions in aqueous media 5

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

162 µg/L

Element analysed:

Nickel

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C; The pH value for the loading of 10 mg/L increased from 6.1 to a maximum of 6.4.

Solubility of metal ions in aqueous media 6

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

3 828 µg/L

Element analysed:

Nickel

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21 .5 ± 1.5 °C;
In media with the loading of 100 mg/L the pH value increased from 6.0 to 7.2.

Any other information on results incl. tables

Observations

In all tests black substance can be observed at the bottom of the test item loaded flasks. In the one day test as well as the full tests with the loadings of 10 and 100 mg/L black substance can also be seen on medium surface in test item loaded vessels.

 

Temperature

The temperature of the thermostatically controlled room was monitored inside an extra vessel filled with ultrapure water by thermo data loggers (Testo 175-T2, Testo AG, Germany). Two data loggers were applied to have a backup in case of malfunction. The temperature profiles of both loggers of the tests for identification of the pH value that maximizes dissolution are shown in Figure 5 (target pH values of 5.5, 6) and Figure 6 (target pH values of 8, 8.5). The temperature profiles for the full tests are depicted in Figure 7 (full test loading 1 mg/L) and Figure 8 (full test loadings 10, 100 mg/L). lt can be clearly seen that the temperatures were always in the range of 21 .5 ± 1.5 °C (upper limit at 23.0 °C and lower at 20.0 °C) for both data loggers in all tiers of the test.

 

 

Solution pH and dissolved oxygen concentrations

Solution pH value of media in the 1 d test (loading 100 mg/L):

At target pH 5.5 the pH value in method blanks over the 1 d were in the range of 5.5 - 5.7. In test item loaded vessels the pH value increased from 5.5 to 6.9.

At target pH 6.0 the pH value in method blanks was in the range of 5.9 to 6.1. In test item loaded vessels the pH value increased from 5.9 to 6.9.

lncreasing of pH values at target pH 5.5 and 6.0 is probably due to the test item properties.

At target pH 8.0 the pH value in method blanks and in test item loaded samples was in the range of 8.0 - 8.1.

At target pH 8.5 the pH value in method blanks was in the range of 8.2 - 8.4. In test item loaded media the pH value was 8.3 - 8.4.

 

Solution pH value of media in the 7 d as well as 28 d test (loadings 1, 10, 100 mg/L):

The pH in method blank media was in the range of 5.9 - 6.2 over 7 days of testing with the loadings of 10 and 100 mg/L.

The pH value for the loading of 10 mg/L increased from 6.1 to a maximum of 6.4.

In media with the loading of 100 mg/L the pH value increased from 6.0 to 7.2.

The increasing pH in test item loaded media can therefore be attributed to the test item properties.

The pH in method blank media as well as in test item loaded samples was in the range of 6.0 - 6.2 over 28 days of testing with the loading of 1 mg/L.

 

The dissolved oxygen concentration in the tests is in accordance with the guidance document [4] of at least 70 % of 8.5 ppm = 6.0 ppm. All measured values are above 6.0 ppm

 

Analytical measurements
The results of quantification of the amount of Li and Ni in samples after 0.2 µm  filtration are compiled in Table 39 and Table 40 (method blanks) and Table 41, Table 42 (test item loaded samples) for the one day test with the loading of 100 mg/L, sampling after 1 d and media at target pH values of 5.5, 6.0, 8.0 and 8.5.
The simulate environmental water which maximizes dissolution in the 1 day test was the pH 6 medium. This medium was therefore used in full tests.

Mass balances
Measurement of samples for the preliminary tests for mass balance as well as the mass balances in full tests with 10 and 100 mg/L was performed on December 01, 2020.
The measurement of samples in 1 mg/L full test from vessels was conducted on February 08, 2021 and the samples from rinsed filters and syringes (full test 1 mg/L) were analytically quantified on February 15, 2021.
To investigate if 1 and100 mg/L of test item can be dissolved by aqua regia, respective preliminary tests were performed. Therefore 1 mg as well as 100 mg of test item was weighed into 960 mL of TD medium at pH 6.

 

100 mg/L preliminary test for mass balance
Regarding a Li amount of 7.2 % in LiNiO2 above mentioned loading contains  theoretically 7.50 mg/L Li.
The Ni amount is 60.8 % corresponding to theoretically 63.3 mg/L Ni.
To attempt to dissolve the test item 250 mL aqua regia was added to 960 mL of pH 6 medium.
The recoveries were within the limits of 100 ± 20 %.

 

1 mg/L preliminary test for mass balance
Regarding a Li amount of 7.2 % in LiNiO2 above mentioned loading contains theoretically 0.076 mg/L Li.
The Ni amount is to 60.8 % corresponding to 0.638 mg/L Ni.
To attempt to dissolve the test item 250 mL aqua regia was added. The recoveries were within the limits of 100 ± 20 %.

 

In these preliminary tests for mass balance recoveries were within 100 ± 20 %. Therefore, full mass balances for the tests with 1, 10 and 100 mg/L loadings were performed.

 

For Li the recoveries are in the range of 100 ± 20 % except vessel 1 for loading 1 mg/L (78.3 % ). For Ni only the loadings of 10 and 100 mg/L are within these limits. At the loading of 1 mg/L the recoveries for Ni were in the range of 49.7 % - 55.1 %.

In contrast to the test with loading 1 mg/L, in tests with the loadings of 10 and 100 mg/L the weighted amount is recovered in aqua regia samples from test item loaded vessels. Therefore, it is not needed to determine the residues of Li and Ni in used filters and syringes from loadings of 10 and 100 mg/L.

 

In the preliminary tests for the mass balance aqua regia was added directly after introducing the test item, whereas the test substance in the full test may react over 28 days (1 mg/L loading) with medium or oxygen. This might form further species which might not be dissolved with aqua regia or form species which remain after filtration of mass balance samples.
The altering of Ni during the 28 days (in TD medium) might be a reason because in the preliminary test (direct addition of aqua regia) the Ni recoveries are within 100 ± 20 %, whereas the 28 d mass balance yielded only about 49.7 - 55.1 % recovery.
In the full mass balance tests for 10 and 100 mg/L the contact time with aqua regia was about three days (start at Friday and sampling Monday), whereas in the test with the loading of 1 mg/L samples were taken after about one day. This shows that reaction times with aqua regia differed.