Degradation of tricyclazole by colloidal manganese dioxide in the absence and presence of surfactants

Abstract

The kinetics of the degradation of tricyclazole by water soluble colloidal MnO2 in acidic medium (HClO4) has been studied spectrophotometrically in the absence and presence of surfactants. The experiments have been performed under the pseudo-first-order reaction conditions with respect to MnO2. To determine the rate constant as functions of [tricyclazole], [MnO2] and [HClO4], the pseudo-first-order reaction conditions have been maintained throughout the entire kinetic runs. The degradation has been observed to be first-order with respect to MnO2 while fractional-order in both tricyclazole and HClO4. The anionic surfactant, sodium dodecyl sulfate (SDS) has been observed to be ineffective whereas nonionic surfactant, Triton X-100 (TX-100) accelerates the reaction rate. However, the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) causes flocculation with oppositely charged colloidal MnO2 and therefore could not be studied further. The catalytic effect of TX-100 has been discussed in the light of the mathematical model proposed by Tuncay et al. [25]. The kinetic data have been exploited to generate the various activation parameters for the oxidative degradation of tricyclazole by colloidal MnO2.