1. Amandine ANDERSON, Patricia MERDY*, Sylvie VILLAIN, Pierre HENNEBERT
FRANCE
Institut National de l’EnviRonnement Industriel et des RisqueS
Processes of Transfers and Exchanges in the Environement
Analytical development dedicated to the study of the temporal evolution of waste - generated colloids
Amandine ANDERSON, Patricia MERDY*, Sylvie VILLAIN, Pierre HENNEBERT
9th ICEENN, Columbia, South Carolina
08/09/2014

2. Introduction
The context
The goal of the study

3. Context High waste production throughout the world:
1- Introduction
2- Identification of problems
3- Temporal evolution of colloids
4- Conclusion
Context
High waste production throughout the world:
for example, 2008 total production in France was
345 Mt (millions tonnes) produced by:
domestic activities for 29.3 Mt
economic activities  for 315 Mt, including 11 Mt considered as dangerous
wastes
storage
recycling
incineration
Necessity to know chemical composition of wastes

4. 1- Introduction
2- Identification of problems
3- Temporal evolution of colloids
4- Conclusion
Context
Legal obligations: industrial producers have to know the bulk chemical composition of their wastes
However, at present, legal obligations do not take into account potentially mobile colloids
In the near future :
many governments including the French government attempt to control the colloidal fraction of waste
How to assess the risk due to colloid transfer ? Needs to better understand the processes
 How to perform an efficient control? Needs for fast, easy, cheap characterization methods

5. The goal of this presentation
1- Introduction
The goal of this presentation
2- Identification of problems
3- Temporal evolution of colloids
4- Conclusion
Determination of environmental risks
5 differents wastes :
① Bauxite residue
② Coastal marine sediments
③Sludge of wastewater treatment plant
④Domestic crushed wastes
⑤Ashes from incineration household
Mobility of colloids
Characterization
Chemical composition
Size measurements ① ② ③ ④ ⑤
What are the most reliable analytical techniques?
ICP-AES
3D fluorescence
Carbon
SEM-EDX
WHAT ARE THE PROBLEMS RELATED TO THESE TECHNIQUES?
DLS
NTA
SEM

6. Fractionation of 5 waste-generated colloids
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Fractionation of 5 waste-generated colloids
Manometer
Pressure: 2bars
Frontal filtration under continuous stirring
leachates
Measurements by
DLS/NTA,
SEM-EDX,
3D fluorescence,
ICP-AES, carbon

7. What are the problems we have encountered?
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
What are the problems we have encountered?
1- Dynamic light scattering (DLS) issues
2- Microscopy artefacts according to drying methods

8. 1- Dynamic light scattering (DLS) issues
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
1- Dynamic light scattering (DLS) issues
Standard Analytical protocol:
5 measurements (12 replicates) in 27 minutes
UNSATISFACTORY
Reliability test of the data over time: we need 9 hours of data aquisition!

9. WE TRIED TO SOLVE THE PROBLEM
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
1- Dynamic light scattering (DLS) issues
Why these artefacts?
Mask effect by the biggest particles due to sedimentation
Heterogeneity of the sample not taken into account
WE TRIED TO SOLVE THE PROBLEM
laser
Analysing with a laser beam targeting the surface of the liquid: needed time was 4h30
sample
Laser
beam
UNSATISFACTORY

10. NANOPARTICLE TRACKING ANALYSIS (NTA)
ALTERNATIVE TECHNIQUE?
NANOPARTICLE TRACKING ANALYSIS (NTA)
Size range: nm
Concentration:
107 à 109 particules/ml

11. Comparison DLS/NTA: Zeta potential
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Comparison DLS/NTA: Zeta potential
Curve from NTA (-44 mV)
Acquisition time: 1 mn
Value from DLS (-18 mV)
Acquisition time: 4h30
MF from Bauxaline

12. Comparison DLS/NTA: particle size
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Comparison DLS/NTA: particle size
Curve from NTA Acquisition time: 1 mn
Peak values from DLS
Acquisition time: 9h
Size classes (nm)
5600
2500

13. WHAT WE SHOULD REMEMBER?
0,6 nm et 6 µm
WHAT WE SHOULD REMEMBER?
DLS : More sensitive to biggest particles (1nm – 6000nm)
NTA : More sensitive to smallest particles (<10nm-2000nm)
== > Complementarity of these 2 techniques
BUT
NTA is easier, faster than DLS and do not require refraction index

14. 2- Microscopy artefacts according to drying methods
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
2- Microscopy artefacts according to drying methods
SEM – EDX : Test of 3 drying methods on the 5 waste samples (0,45µm filtrates)
Drying in the ambient air
Lyophilisation at -18°C
Lyophilisation with liquid nitrogen

15. Temporal evolution and analysis of colloids
1- Introduction
1- Introduction
1- Introduction
2- Identification of the problems
2- Identification of the problems
2- Material and methods
3- Temporal evolution of colloids
4- Conclusion
Temporal evolution and analysis of colloids
Is the time elapsed after filtration to be taken into account in characterization protocols?
Is this time significant with regard to transfer processes?

16. Temporal evolution and analysis of colloids
1- Introduction
1- Introduction
1- Introduction
2- Material and methods
2- Identification of the problems
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Temporal evolution and analysis of colloids
Micro filtrate evolves after filtration
Size, zeta potential, organic matter patterns

17. Microfiltrate from bauxite residue
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Microfiltrate from bauxite residue
Measurements achieved by DLS

18. Microfiltrate from incineration household ashes
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Microfiltrate from incineration household ashes
Very small organic matter particles (few nm Ø)
(non detectable by DLS but detectable by NTA)
Organic carbon in colloidal phase : around 13%
Very large organic matter particles (more than 100µm): due to post-filtration aggregation
Why getting interested in organic matter studies?
It is a complexing agent that plays an key role in metal transfer

19. Microfiltrate from incineration household ashes
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Microfiltrate from incineration household ashes
3D-fluorescence spectra C
C, humic-like
A, fulvic-like
90 days
Humic ratio (RC,A)= IC / IA

20. Conclusion Regarding scientific purposes
1- Introduction
2- Identification of the problems
3- Temporal evolution of colloids
4- Conclusion
Conclusion
Regarding scientific purposes
Special care has to be taken when acquiring data according to the technique
Regarding the development of a regulation suited to colloids
Protocols have to consider variability and polydispersity of colloids: NTA and DLS seem both necessary
Protocols have to consider ageing
Focus on organic matter