Abstract (Invited)

From Fundamental to Application of Ultrasound for Water Treatment

C.Petrier (Laboratoire de Chimie Moleculaire et Environnement, ESIGEC-Universite de Savoie, Le Bourget du Lac, France)

e-mail: christian.petrier@univ-savoie.fr

Since 1990 there is a growing interest of ultrasound use in processes for water treatment. Propagation of an acoustic wave in water can conduct to elimination of organic contaminants through direct thermal mineralization or induced chemical modification. Most of the .ultrasonic activity. is linked to the phenomenon of ultrasonic cavitation. A molecule that exhibits high vapor pressure properties will be destroyed thermally into the bubble of cavitation. An hydrophilic structure will be transformed and removed by way of reactions involving hydroxyl radicals HO. In this second case, HO radicals produced in the bubble (reaction 1-3) react outside with the organic targets M (reaction 4) 1- H2O -> H + HO 2- O2 -> 2O 3- H2O + O -> 2 HO 4- HO + M -> HOM ->->-> products Single use of ultrasound application or ultrasound combined with oxidative processes has demonstrated its potential for water treatment (ultrasound-ozone, ultrasound-photocatalyse, ultrasound-Fenton.s reagent, ultrasound-UV). Currently the industrial development of the process requires yields enhancement that can be obtained taking into account parameters that affect formation and behavior of the bubbles of cavitation. C. Petrier, D. Casadonte, Advances in Sonochemistry, 2001, 6, 91-109. The sonochemical degradation of aromatic and chloroaromatic contaminants.

Section : 11