Effect of temperature on methylene blue decolorization in aqueous medium in electrical discharge plasma reactor

Abstract

This study investigates the effect of bath solution temperature on methylene blue decolorization in a point-to-plate electrical discharge plasma reactor. The results show an increase in the initial percentage of dye decolorization with an increase in the bath solution temperature from 4 to 28 °C, but from 28 to 37 °C there was no change. However, when the temperature was raised to 47 °C the initial dye decolorization percentage decreased. The hydrogen peroxide (H2O2) formation in water during the plasma treatment decreased as the bath temperature increased from 4 to 47 °C. The dye decolorization reaction occurred via a complex mechanism where zero- and first-order processes took place at the same temperature, following zero-order in the initial step and first-order with the progress of the reaction. The activation energy involved in the first-order process was 13.09 kJ mol-1. ©2011 Sociedade Brasileira de Química.