Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Abstract

Recebido em 11/6/01; aceito em 8/11/01 SONOCHEMICAL PRODUCTION OF OXIDIZING SPECIES IN WATER SOLUTION SATURATED WITH CARBON TETRACHLORIDE. In this work the CCl 4 degradation in aqueous solution by sonication with 40 kHz commercial ultrasonic bath was investigated. Sonochemical degradation of CCl 4 occur by the cleavage of C-Cl bond into the cavitation bubbles. Oxidation reactions and the pH decreasing in the bulk solution during sonication were attributed to chlorine radicals produced by CCl 4 sonolysis, leading to increase the chloride concentration. The formation of oxidizing agents was evaluated employing I-and Fe 2+ ion solutions, converted to I 2 and HIO, and Fe 3+ , respectively. The amount of chloride and hydronium ions produced after 3 min of irradiation was 11.52 and 12.19 mmol, respectively, suggesting that the same reaction was involved to produce these ions. Fe 2+ oxidation and the pH variation were monitored to estimate chlorine radical formation rate in the presence (0.107 mmol s-1) and absence (0.092 mmol s-1) of metallic ion during the first minute of sonication.