Photocatalytic degradation of dimethoate using nanosized TiO2 powder Original Research Article

Photocatalytic degradation of dimethoate using nanosized TiO2 powder at different conditions were investigated in an XPA-II type reactor. The degradation efficiency of dimethoate increases with elevated concentration of TiO2 suspension up to 0.6 g/L, while the efficiency reduced slightly when the concentration of TiO2 is above 0.6 g/L due to the shielding effect. The kinetic rate of dimethoate degradation decreases with increasing initial concentration of dimethoate, which can be described using the first-order model. An alkaline environment and enhanced power of UVlamp are conducive to dimethoate degradation. The presence of H2O2/K2S2O8 and ultrasonic irradiation can significantly enhance dimethoate degradation. However, the increment in degradation efficiency may be suppressed to some extent due to being scavenged of ·OH species by excessive H2O2/K2S2O8 at a high concentration level.