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 ºC, but from 28 to 37 ºC there was no change. However, when the temperature was raised to 47 ºC 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 ºC. 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.
methylene blue; decolorization; temperature effect; electrical discharge plasma
