Advanced oxidation of methyl tert-butyl ether (MTBE) by UV/TiO_2 and H_2O_2-UV/TiO_2 processes

摘要

This study investigated photocatalysis of MTBE via both UV/TiO_2 and H_2O_2-UV/TiO_2 processes. Several experimental parameters including pH level, H_2O_2 concentration, TiO_2 dosage and light intensity were investigated. The experimental results demonstrated the degradation of MTBE following a pseudo first-order reaction in both reaction systems. Faster degradation rates were observed in alkaline solution for the UV/TiO_2 system, but for the H_2O_2-UV/TiO_2 system, faster degradation rates were detected in acidic solution. More dosage of TiO_2 and irradiated light intensity were beneficial for the photocatalysis of MTBE. However, a peak reaction rate was observed at a TiO_2 concentration of about 500 mg/L. The experimental results also indicated that the degradation rate of MTBE was enhanced by the addition of H_2O_2. H_2O_2 could be a more efficient electron acceptor than oxygen for retarding recombination of electron-hole pairs. The degradation rate in the H_2O_2-UV/TiO_2 system was about 2.8 times faster than that in the UV/TiO_2 system for solution pH below 5, and the rate increased 30% for solution pH above 6. In addition, it is observed that the reaction rate of MTBE increased quickly with H_2O_2 concentration at low H_2O_2 dosages, but the rate was independent of H_2O_2 dosage when adding too much H_2O_2.