Interactions of organic matter with micropollutants and becoming during coagulation ; Interaction de la matière organique avec les micropolluants anthropiques et devenir lors de la coagulation

Several molecular weights humic-like compounds were synthesised by oxidation and polymerisation of catechol and glycine or triglycine, and compared to natural suspended matters extracts (Moselle River). The reaction kinetics were monitored by infra-red and fluorescence. This showed the role of the incorporated nitrogen in the overall fluorescence spectra. Furthermore, it bas been correlated to their air/water interface behaviour. The binding capacity of several priority pollutants with these organic molecules was quantified using fluorescence derived methods. Atrazine and sulcotrione (herbicides), as well as a non-ionic nonyl phenol (surfactant) present no significant fluorescence quenching with humic substances. An entrapment of pyrene (Hydroxy Aromatic Polycyclic, HAP) was shown using fluorescence and interfacial tension measurements. Sodium Dodecyl Sulfate (SDS) and Cet yI Trimethyl Ammonium Bromide (CTAB) interact with these molecules as well. This was shown at the molecular level, using fluorescence quenching of the humic like material. Also, this interaction was pointed out using air/water interfacial tension measurements. The coagulation mechanism between ferric nitrate and natural as well as synthetic organic molecules bas been developed thanks to this technique. Iron status remains unchanged as far as its oxidation status is concerned. However, different organic matter complexation sites could be discriminate by iron loss- spectroscopy (EELS) coupled with Mossbauer technique. Finally, optimum conditions for pyrene removal seem to be independant of the optimum coagulation dose. Conformational changes of organic structures could be involved in the mechanism. ; Des acides humiques de synthèse de différentes tailles moléculaires, obtenus par oxydation de catéchol et de glycine ou de triglycine, ont été caractérisés et comparés à des extraits naturels d'acides humiques associés aux matières en suspension aquatique (rivière Moselle). Le suivi cinétique de leur synthèse, par spectrofluorimétrie et ...