Mécanismes d’élimination d’acides organiques aromatiques par le sulfate d’aluminium et effet de la minéralisation

Abstract

The aim of this work was to study removal of aromatic organic molecules in distilled water by aluminium sulphate. Coagulation-flocculation of these compounds highlighted the complexity of the involved mechanisms and their close dependence on nature and number of acid groups substituting the aromatic ring. The position of substituents one over the other appeared to contribute evenly to explain the differences in the disposal yields observed. The adsorption could be the predominant mechanism during the coagulation-flocculation of gallic acid and pyrogallol. In addition, removal of pyromellitic acid at pH = 5.5, can be explained by the existence of chemical interactions between the pyromellitic acid and the cationic soluble species of aluminum. When these organic compounds were dissolved in mineralized groundwater, the results showed that the water mineralization could be have promoter or inhibitor impact according to the structure of the organic compounds tested. Thus, compounds with hydroxyl function (pyrogallol and gallic acid) beheld their disposal yields increase from the water Ifri (Conductivity = 0.64ms/cm; TH = 48 oF) to the water of Biskra the most mineralized (Conductivity = 4.75ms/cm; TH = 208 oF). The increased mineralization appeared also inhibit the elimination of salicylic acid and especially that of acid pyromellitic.