Abstract
This study investigate the potential of enhancing the sonochemical destruction of aqueous organics using silica and peroxide. The effect of solution pH, silica, and/or H2O2 with sonolysis was examined for destruction of 2-chlorophenol (2-CP). Sonochemical removal of 2-CP was higher at lower-solution pH (below the pKa of 2-CP). Presence of silica increased the removal rate by possibly creating more cavities for destruction of 2-CP. The optimum dosage of silica was 5 g/L. Sonolysis experiments were conducted with H2O2 dosages of 50, 75, and 100 mg/L. H2O2 dosage of 100 mg/L was observed to enhance 2-CP destruction by 27% in 60 min as compared to ultrasound alone. The optimum ratio of H2O2 to silica was 100 mg/L: 5 g/L and it increased destruction of 2-CP by almost twofold as compared to ultrasound alone. The chloride ion production increased with an increase in H2O2 dosage in the presence of silica. After 60 minutes of sonication, about 49% chloride ion production was observed in the presence of 5 g/L silica together with 100 mg/L H2O2. The percentage of destructed 2-CP that converted to chloride ions during ultrasound destruction of 2-CP was improved in the presence of silica and/or H2O2, as compared with ultrasound alone. Presence of silica and peroxide aids in enhancing conversion of destructed 2-CP to chloride ions, thereby reducing formation of chlorinated intermediate products. The kinetics study showed that silica and peroxide function independently and do not exhibit synergism during sonolysis.