The machanism studies on sonophoto-degradation of chlorophenol by free radical

A ultrasound assisted photocatalysis (US-UV) was used for photo-degradation of 4-chlorophenol (4CP), and the mechanism of sonophoto-degradation of 4CP by free radical was studied. The results showed the synergistic effect was notable. ·OH radical production rate and 4CP degradation rate complied with zero-and first-order kinetic equation. Meanwhile Cl^-1 production rate did not comply with simple kinetic equation. Adding ·OH radical scavenging the photogenerated electrons on the TiO₂ surface, but when the concentrations of metal ions in the solution increased to a certain level, short-circuiting phenomenon emerged which reduced the degradation rate of 4CP greatly. Furthermore diffuse reflectance UV-Vis spectra indicated that surface complexes were formed and surface complexes were likely oxidized by free radicals at first.