Destruction of carbon disulfide in aqueous solutions by sonochemical oxidation.

Carbon disulfide (CS(2)) is toxic to animals and aquatic organisms, and can also decompose to carbonyl sulfide (OCS) and hydrogen sulfide (H(2)S) in aqueous environment. The kinetics of the sonochemical degradation of aqueous CS(2) was studied in a batch reactor at 20kHz and 20 degrees C, and the effects of process parameters (e.g. concentration, ultrasonic intensity, irradiating gas) investigated. The concentrations of unbuffered CS(2) solutions used were (6.4-7.0) x 10(-4), 10.5 x 10(-4) and (13.2-13.6) x 10(-4)M and the intensities were varied from 14 to 50W. The reaction rate was found to be zero-order and the rate constant for the degradation at 20 degrees C and 14W in air was 21.1 microM/min using the largest initial concentration range studied. At the same initial concentration range but at 50W (39.47W/m(2)) the degradation rate of CS(2) was 46.7 microM/min, more than two times that at 14W (11.04W/m(2)). The rate of CS(2) sonochemical degradation in the presence of the different gases was in the order of He>air> or =N(2)O>Ar; the rate with helium was found to be about three times that of argon. The formation of sulfate (SO(4)(2-)) as reaction product with air as the irradiating gas was enhanced in the presence of hydrogen peroxide (H(2)O(2)) and inhibited in the presence of 1-butanol. The sonochemical oxidation of CS(2) may prove to be an efficient and environmentally benign way for the removal of this hazardous pollutant from natural water and wastewater.