Enhanced rates of sonolytic degradation of CCl{sub}4 in the presence of Fe{sup}0 are demonstrated. In Ar-saturated solutions, the first-order rate constant for CCl{sub}4 degradation is k{sub}(US) = 0.107 min{sup}-1, whereas in the presence of Arand Fe{sup}0, the apparent first-order rate constant is found to depend on the total surface area of elemental iron in the following fashion: k{sub}(obs) = (k{sub}(US) + k{sub}Fe{sup}0A{sub}Fe{sup}0) min{sup}-1, where k(US) = 0.107 min{sup}-1,k{sub}Fe{sup}0 = 0.105 L m{sup}-2 min{sup}1, and A{sub}Fe{sup}0) = reactive surface area of Fe{sup}0 in units of m2 L{sup}-1. In the coupled ultrasound and iron system, the contribution to the overall degradation rate by direct reaction with Fe{sup}0results in an overall rate enhancement by a factor of 40. These enhancements are attributed (1) to the continuous cleaning and chemical activation of the Fe{sup}0 surface by the combined chemical and physical effects of acoustic cavitation and (2) toaccelerated mass transport rates of reactants to the Fe{sup}0 surfaces. Additional kinetic enhancements are due to the production of H{sup}+ during the course of the reaction. Furthermore, the concentrations of the principal reaction intermediates,C{sub}2C1{sub}6 and C{sub}2C1{sub}4, are influenced substantially by the total available surface area of Fe{sup}0.
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