Rate of dibutylsulfide decomposition by ozonation and the O 3/H 2O 2 advanced oxidation process

Abstract

A process of dibutylsulfide (DBS) oxidation using advanced methods of oxidation with ozone and hydrogen peroxide was studied. It was demonstrated that depending on pH value there are two mechanisms of DBS oxidation present: ionic and radical. The ionic mechanism predominates in acidic environment and the radical mechanism predominates in alkaline environment. At high pH ozone stability decreases and hydrogen peroxide has a deciding effect on DBS oxidation rate. At pH 9, and at high concentration of hydrogen peroxide (ranging from 0.1 to 1 mol/L), a clear increase in DBS decomposition rate was observed. That was caused by production of hydroperoxide radicals in reaction of hydrogen peroxide and ozone. In solutions pH value of which is close to 2, the rate of DBS oxidation by ozone alone is slower than in a O 3/H 2O 2 system, regardless the H 2O 2 concentration. For higher H 2O 2 concentrations (ranging from 0.1 to 1 mol/L), regardless the pH value of the solution, oxidation in a O 3/H 2O 2 system is faster, compared to a situation in which ozone is a sole oxidizer. For H 2O 2 concentrations below 0.1 mol/L and when pH > 2 DBS oxidation in O 3/H 2O 2 system is slower compared to the situation in which ozone was the only oxidizer.