N-[3-(dimethylamino)propyl]stearamide

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 July - 24 October 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

other: soil, sediment and sewage sludge

Test material

Test material information

Constituent 1

Reference substance name:

Docosyltrimethylammonium chloride

EC Number:

241-327-0

EC Name:

Docosyltrimethylammonium chloride

Cas Number:

17301-53-0

IUPAC Name:

N,N,N-trimethyldocosan-1-aminium chloride

Constituent 2

Reference substance name:

[14C]-C22 ATQ

IUPAC Name:

[14C]-C22 ATQ

Radiolabelling:

yes

Study design

Test temperature:

20 +/- 2°C

Batch equilibrium or other method

Analytical monitoring:

yes

Details on sampling:

Determination of adsorption equilibrium (kinetics experiment):
- Concentration: 1 mg/L
- Sampling interval: 3, 6, 24 and 48 h (adsorption), 3, 6, 24 and 48 h (desorption)
Determination of isotherms:
- Concentrations: 0.01 - 0.05 - 0.2 - 0.5 - 1 mg/L
- Sampling interval: 24 h (adsorption) and 24 h (desorption) for soils; 42 h (adsorption) and 6 h (desorption) for sediment and sludge

Details on matrix:

CRANFIELD 164 SOIL

COLLECTION AND STORAGE
- Geographic location: Farditch Farm, Chelmorton, Buxton, United Kingdom (OS map reference SK 1050269133)
- Storage conditions: refrigerated after receipt; ambient temperature after sieving/air drying
- Storage length: maximum 9 months
- Soil preparation: sieved (2 mm) and air dried

PROPERTIES
- Soil texture
- % sand: 20
- % silt: 52
- % clay: 28
- Horizon: 10-20 cm
- Soil classification system: silty clay loam (USDA)
- pH: 6.0
- Organic carbon (%): 3.7
- CEC (meq/100 g): 22.8
- Water holding capacity (%): 65.7


CRANFIELD 277 SOIL

COLLECTION AND STORAGE
- Geographic location: Posher Farm, Upton, Leamington Spa, Warwickshire, United Kingdom (OS map reference SP 3706562304)
- Storage conditions: Ambient temperature after receipt
- Storage length: maximum 9 months
- Soil preparation: sieved (2 mm) and air dried

PROPERTIES
- Soil texture
- % sand: 19
- % silt: 24
- % clay: 57
- Horizon: 0-20 cm
- Soil classification system: clay (USDA)
- pH: 7.4
- Organic carbon (%): 2.7
- CEC (meq/100 g): 22.4
- Water holding capacity (%): 66.6


CRANFIELD 299 SOIL

COLLECTION AND STORAGE
- Geographic location: Stoke Hill Farm, Erlestoke, Wiltshire, United Kingdom (OS map reference ST 9518952867)
- Storage conditions: Ambient temperature after receipt
- Storage length: maximum 9 months
- Soil preparation: sieved (2 mm) and air dried

PROPERTIES
- Soil texture
- % sand: 28
- % silt: 46
- % clay: 28
- Horizon: 3-20 cm
- Soil classification system: loam (USDA)
- pH: 7.6
- Organic carbon (%): 2.9
- CEC (meq/100 g): 14.9
- Water holding capacity (%): 62.1


SW SEDIMENT

- Location: Schoonrewoerdse Wiel, Leerdam, The Netherlands
- Details on collection: sediment was sampled from the upper layer (0-10 cm) from the middle of the pond (depth 8 m)
- Storage conditions: refrigerated after receipt; ambient temperature after sieving/air drying
- Textural classification (i.e. %sand/silt/clay): 44/31/25
- pH: 7.6
- Organic carbon (%): 6.2
- CEC (meq/100 g): 21.7


TILBURG SLUDGE

- Type of sludge: Mix of domestic and industrial waste water
- Source of sludge: Sewage treatment plant RWZI Tilburg-Noord, Tilburg, The Netherlands
- Oxygen status: aerobic
- Details on preparation: The sludge was allowed to settle at ambient temperature. The water layer was separated as much as possible from the precipitated sludge and discarded. The sludge was centrifuged (700 g, 5 min) and the supernatant was decanted. The sludge was frozen at -80°C and subjected to freeze-drying. After freeze-drying, the sludge was sieved over a 2 mm sieve and dried overnight in an oven at 103°C.
- Storage conditions: ambient temperature
- Textural classification (i.e. %sand/silt/clay): 2/39/59
- pH: 6.6
- Organic carbon (%): 37.5
- CEC (meq/100 g): 96.2

Details on test conditions:

- Type, size and further details on reaction vessel: 100 mL Erlenmeyer flasks
- Solution: 0.01 M CaCl2 solution (1.47 g calcium chloride dehydrate/L Milli-Q water)
- Amount of soil/sediment/sludge and water per treatment: 0.45 g soil/sediment/sludge and 45 mL and 0.01 M CaCl2 solution
- Soil/sediment/sludge-water ratio: 1:100
- Number of reaction vessels/concentration: 2
- Measuring equipment: LSC
- Are the residues from the adsorption phase used for desorption: yes

Computational methods:

The Freundlich adsorption and desorption isotherm parameters were calculated by fitting the Freundlich isotherm to the data. Optimisations were performed using the program ModelMaker (AP Benson, Wallingford, Oxfordshire, UK).

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

> 950 - < 516 000

Adsorption coefficient 2

Type:

log Koc

Value:

> 3 - < 5.7

Results: Batch equilibrium or other method

Adsorption and desorption constants:

See tables below

Recovery of test material:

At the end of the adsorption phase more than 97% of the applied activity was recovered; at the end of the desorption phase more than 94% of the applied activity was recovered .

Concentration of test substance at end of adsorption equilibration period:

Adsorption equilibrium was reached within 6 hours for soil and after 48 hours for sediment and sludge. The amount of C22-Trimethylammonium Chloride adsorbed to sediment and sludge was ca. 80% whereas >95% was adsorbed to soil.

Concentration of test substance at end of desorption equilibration period:

Desorption equilibrium was reached within 6 hours for each test system. Less than 15% desorbed

Any other information on results incl. tables

C22-Trimethylammonium Chlorideadsorption and desorption isotherms could be described by the Freundlich equation. Freundlich isotherm parameters are summarised in the tables below.

 

Freundlich adsorption isotherm parameters forC22-Trimethylammonium Chloride

Test system	KF^ads(L/kg)	KF,oc^ads(L/kg)	1/n	r^2	data points
Cranfield 164 soil	0.73 x 10^3	19.8 x 10^3	0.79	0.929	10
Cranfield 277 soil	13.9 x 10^3	516 x 10^3	1.09	0.956	10
Cranfield 299 soil	1.53 x 10^3	52.8 x 10^3	0.82	0.976	10
SW sediment	1.08 x 10^3	17.4 x 10^3	0.95	0.991	10
Tilburg sludge	0.36 x 10^3	0.95 x 10^3	1.03	0.938	9

 

Freundlich desorption isotherm parameters forC22-Trimethylammonium Chloride

Test system	KF^des(L/kg)	KF,oc^des(L/kg)	1/n	r^2	data points
Cranfield 164 soil	6.61 x 10^3	179 x 10^3	1.04	0.858	10
Cranfield 277 soil	2.41 x 10^3	89.3 x 10^3	0.85	0.971	10
Cranfield 299 soil	13.8 x 10^3	476 x 10^3	1.04	0.874	10
SW sediment	3.10 x 10^3	50.0 x 10^3	1.08	0.886	10
Tilburg sludge	4.04 x 10^3	10.8 x 10^3	1.05	0.951	10

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

C22-Trimethylammonium Chloride adsorption isotherms could be described by the Freundlich equation. KF, ocads values were 19.8 x 103 L/kg (Cranfield 164 soil), 516 x 103 L/kg (Cranfield 277 soil), 52.8 x 103 L/kg (Cranfield 299 soil), 17.4 x 103 L/kg (SW sediment) and 0.95 x 103 L/kg (Tilburg sludge).