The kinetics and mechanism of ultrasonic degradation of p-nitrophenol in aqueous solution with CCl_4 enhancement

摘要

The ultrasonic degradation of p-nitrophenol (p-NP) in aqueous solution with CCl_4 enhancement was studied. The effects of operating parameters such as CCl_4 dosage, ultrasonic power, media temperature, the initial concentration of p-NP and initial pH value of the aqueous solution on the degradation of p-NP were investigated, and the enhancement mechanism of CCl _4 for p-NP sonolysis was also discussed. The results showed that the sonochemical degradation of p-NP was obviously enhanced by adding CCl _4. It attributed to the increase OH radicals concentration in the presence of CCl_4 as a hydrogen atom scavenger, and the formation of some oxidizing agents such as free chlorine and chlorine-containing radicals. The degradation of p-NP follows a pseudo-first-order kinetics. The degradation rate of p-NP increased with decreasing the temperature, the initial pH value of the solution and decreasing the initial concentration of p-NP. It was also found that p-NP can be mineralized in this process.