EFFET DE LA COAGULATION-FLOCULATION / POST-CHLORATION SUR LA REACTIVITE DE L’ACIDE PYROMELLITIQUE ET L’ACIDE SALICYLIQUE EN EAU DISTILLEE

Abstract

The objective of this study is to demonstrate the reactivity of simple organic compounds such as pyromellitic acid and salicylic acid towards chlorine on the one hand and the other hand of aluminium sulphate. It is also to test the impact of a combined treatment flocculation / chlorination on the removal of these organic compounds. The results of  the coagulation-flocculation trials of salicylic acid and pyromellitic acid with aluminum sulfate in distilled water showed that their removal to a pH = 7 is performed with variable yields according to the organic compound structure. It also showed the complexity of the mechanisms involved and their close dependence on the nature and number of acid groups substituting the aromatic ring. Formation in significant amounts of aluminum hydroxide may be made and then promote a physical adsorption phenomenon or a ligand exchange with the OH^- ions to the surface of this hydroxide.

Experimental chlorination tests highlighted that chlorine consumption potentials are significant.

When the solutions of the organic acids may have undergone a coagulation-flocculation followed by a post-chlorination, the products formed are, according to the dosage of chlorine, largely, complex aromatic structures and still absorb in the UV.