Sonochemical decomposition of hydrazine in water: Effects of coal ash and pH on the decomposition and adsorption behavior

Sonochemical decomposition of hydrazine in aqueous suspension of coal ash particles was investigated in the different pH solutions. It was clearly found that the initial rate of hydrazine decomposition and adsorption is strongly dependent on the amount of coal ash and pH. At pH 1, the amount of the hydrazine adsorption on coal ash was very small and hydrazine was mainly decomposed by ultrasonic irradiation. At pH 4, hydrazine was mainly adsorbed on coal ash and not decomposed by ultrasonic irradiation. At pH 8, the sonochemical decomposition and the adsorption on coal ash proceeded simultaneously. These results were due to the interactions between the degree of the protonation of hydrazine, the electric charge of coal ash and the amount of OH radicals formed in the sonolysis of water.