Asbestos Containing Wastes (ACW) were mixed with chemical additives and heated with microwaves. Eternit, Progypsol and Spray coated Amosite were thermo-chemically treated and the mineral residues recycled in mortar. Samples were analysed before and after thermal treatment by Scanning Electron Miscroscopy with Field Emission Gun (SEM FEG) and Energy Dispersive X-ray analysis (EDX) coupled to the SEM FEG. Mineralogy was examined by microprobe. X Ray diffraction (XRD) was used to identify the crystal lattice of products before and after melting. Additives such as borates, phosphates and sodium carbonate were introduced to lower the fusion temperatures and the treatment costs. Thermogravimetric analysis and differential scanning calorimetry were used to estimate melting effects due to the additives. EPR spectroscopy was used to study the environment of iron ions embedded on asbestos surfaces and demonstrate fiber transformation to a more isotropic phase. Magnesium silicates (serpentine group) were found in Eternit and Progypsol samples, and iron silicates (amphibole group) in Spray Coated Amosite samples. Observations by SEM illustrate differences in the structure between raw and treated materials but elemental analyses show the same chemical compositions. XRD patterns confirm the transformation of asbestos fibers into other crystalline materials. Borates are most effective for lowering the temperature of thermal transformation. The ground mixtures begin to melt at 900°C with borates compared to other melting products where the melting temperature is around 1,000-1,100°C. Heating with fusion additives allows irreversible transformation of the asbestos fibrous structure and recycling of the residues as filling materials in mortars. Thermal treatment seems to be the most effective process to transform and inactivate asbestos fibers from starting materials. Recycling treated ACW in mortar shows a decrease of mechanical properties when replacing cement or aggregate, but samples with 10 wt% ACW replacing aggregate show tensile strengths of 10 MPa, close to the value for the reference mortar with no ACW. Reuse of treated ACW would prevent stockpiling in hazardous waste landfills.

Conditions for tributyltin (TBT) solubilization and degradation were investigated. These conditions were optimized to remove or degrade organotin compounds (OTC) in spiked kaolin. TBT-spiked kaolin and reagents with specific chemical properties were tested in a batch reactor using a solid matrix model. The final concentrations of butyltin compounds in kaolin were determined by gas chromatography coupled with a pulsed flame photometric detector. Best results were obtained under acidic conditions (2

Glycidoxypropyltriethoxysilane (GPS) was used as a reactive silane to graft metal- complexing ligands onto silica gel in aqueous media under mild conditions. The synthesis entailed the reaction of GPS with silica gel, followed by grafting polyamine onto the epoxy functional group. GPS was added to silica gel in ethanol with 5 vol. % water and the mixture was air-dried for 24 h. Subsequently, excess amounts of polyamines: triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine were individually added to the silanised silica, followed by solvent evaporation and ovendrying at 60°C. The ligand-grafted silica gel particles showed a rapid heavy metal uptake in batch or flow-through experiments with capacities reaching 0.1 mmol g−1 for copper, zinc, cadmium, or lead ions. Columns packed with the modified particles could be readily regenerated by acid-washing with only a small decrease in activity. The particles could be used for the colourimetric detection of heavy metal pollution or for pre-concentration for analytical purposes. Competition between Cu2+, Zn2+, Pb2+, and Cd2+ ions for the three synthesised silica showed that Cu2+ ions were adsorbed more strongly than the other metal ions. The general method developed can be applied to graft other molecules with terminal amino groups for other purposes.

Investigations on thermochemical transformation of asbestos fibers followed by computer aided image analysis are presented. Asbestos Containing Wastes (ACW), notably asbestos-cement, were characterized before and after microwave heating with additives aimed at reacting with and transforming asbestos fibers. Microprobe analysis helped determine the chemical compositions. X ray diffraction (XRD) was used to confirm decomposition of asbestos fibers during microwave heating. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the environments surrounding the iron ions present in asbestos fibers. Analytical results show the presence of magnesium silicates in ACW samples, which is typical for asbestos fiber composition (chrysotile). Electronic microscopy observations show a difference in morphology between raw and treated materials. Characteristic XRD reflections of asbestos fibers disappeared in the treated samples demonstrating the transformation of asbestos fibers into other types of solids. Computer-Assisted-Image analysis allowed confirming automatically the absence of fibers following heating according to the isoperimetric index of observed particles. EPR spectroscopy confirmed the transformation of anisotropic fibers into more isotropic symmetry following melting. Thermochemical treatment was effective in transforming asbestos fibers in ACW into non-asbestos products. The advantage of microwave heating lies in the possibility to transport the lightweight oven to the ACW dismantling site thus avoiding transportation hazards. Computer aided Image analysis would allow screening more images automatically to ascertain the absence of risks related to remaining fibers in numerous treated ACW samples.