Abstract
In a worrying environmental context, freshwater resources preservation became a priority. New ecologic remediation methods have to be developed. The first part of this thesis proposes a technology for water decontamination supporting aquatic ecosystems by solving two major problematics :- fighting against alien invasive species proliferation- developing efficient depollution systems transforming this too abundant vegetal resource into filters capable of retaining metallic elementsThe first part of this work has been dedicated to a fundamental research on the Fe(II) and As(V) biosorption using these new biomaterials. The phytotechnologies studied have then been expanded to two demonstrative sites (Gard and Aude, France) suffering from a heavy pollution of metal traces elements : Fe, Zn for the first and As for the second.The first mining effluent treatment with our vegetal filters became an important source of Fe(II) enriched biomass, which has been valorized as a new resource for the decontamination of As polluted waters, based on their natural affinity. The second bio-inspired depollution system has also been applied successfully in natura.A second valorization of the Fe rich filters has been applied in the field of chemistry. For a long time left behind, iron is today considered as a resource of the future: its abundance and harmlessness are making it very useful in sustainable chemistry, and the Fe biosorption opens the door for a new perspective: its recycling. We have thus studied the use of an iron salt, FeCl3.6H2O, in organic synthesis and shown it was a direct source for green ionic liquid, capable of promoting electrophilic substitution with extremely soft conditions.Finally, the study of Ecocatalysis would lead to another promising valorization of iron riche biomaterials. This concept allows the valorization of the biomaterials enriched with metallic elements, by transforming them into chemical tools of high added value.