Sonochemical degradation of a polydisperse nonylphenol ethoxylate in aqueous solution

The ultrasound (363 kHz) induced decomposition of a commercially available polydisperse nonylphenol ethoxylate surfactant (Teric GN9) has been investi gated. The initial rate of decomposition was found to be a function of the monomer concentration of the surfactant below and above the critical micell e concentration. Based on HPLC, TOC, GC, and sonoluminescence quenching mea surements, we conclude that the initial pathway for the decomposition of th e Teric GN9 occurs via a combination of thermal breakdown and radical attac k on surfactant molecules adsorbed at the surface of cavitating bubbles. Ne arly 90% mineralization and/ or degradation into volatile products of the s urfactant was achieved after sonication fdr 24 h.