Photocatalytic degradation of chloramphenicol and tartrazine using Ag/TiO_2 nanoparticles

摘要

Photocatalytic degradation of chloramphenicol (CAP) and tartrazine (TAZ) was studied in the aqueous suspensions of silver-modified TiO_2 (Ag/TiO_2) nanoparticles under ultraviolet (UV) light irradiation. Ag/TiO_2 nanoparticles were prepared with chemical reduction method and characterized by X-ray diffraction (XRD), scanning electron micrographs (SEM), energy dispersive X-ray micro analysis (EDX), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. XPS measurement indicates that Ag mainly exists in the Ag~0 state on the TiO_2 nanoparticles surface. The effects of the operational parameters, such as silver concentration, photocatalyst loading, initial substrate concentration, light intensity, and calcination temperature were evaluated. It was found that the photocatalytic efficiency of TiO_2 nanoparticles for the degradation of CAP and TAZ can be significantly improved by depositing an optimum amount of Ag nanoparticles. By comparing the removal efficiency of CAP and TAZ at the similar conditions, it was observed that the photodegradation rate of TAZ was faster than that of CAP. Total organic carbon (TOC) removal was measured at optimum conditions to quantify the mineralization of the pollutants. Above 84 and 89% mineralization of CAP and TAZ was observed using 120 min irradiation.