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

Introduction The context The goal of the study

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

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

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

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

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

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!

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

NANOPARTICLE TRACKING ANALYSIS (NTA) ALTERNATIVE TECHNIQUE? NANOPARTICLE TRACKING ANALYSIS (NTA) Size range: 10-2000nm Concentration: 107 à 109 particules/ml

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

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

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

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

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?

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

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

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

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

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