Investigation on degradation of dyestuff wastewater using visible light in the presence of a novel nano TiO2 catalyst doped with upconversion luminescence agent

A new upconversion luminescence agent, 40CdF2·60BaF2·1.0Er2O3, was synthesized and its fluorescent spectrum was determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks shown in the fluorescent spectrum whose wavelengths are all below 387 nm under the excitation of 488 nm visible light. This upconversion luminescence agent was mixed into nano rutile TiO2 powder by ultrasonic and boiling dispersion and then a novel doped nano TiO2 photocatalyst utilizing visible light was firstly prepared. The doped nano TiO2 powder was charactered by XRD and TEM and its photocatalytic activity was checked through the photocatalytic degradation reaction of azo fuchsine as a model compound under the visible light irradiation emitted by 6 three basic color lamps. Otherwise, in order to compare the photocatalytic activities the same experiment was carried out for undoped TiO2 powder. The degradation ratio of azo fuchsine in the presence of doped nano TiO2 powder reached 95% under visible light irradiation within 24 h, which was obviously higher than the corresponding degradation ratio of 21% in the presence of undoped nano rutile TiO2 powder. It indicates that the upconversion luminescence agent prepared as dopant can effectively turn visible lights to ultraviolet lights that are absorbed by nano TiO2 particles to produce the electron–cavity pairs. All the results show that the nano rutile TiO2 powder doped with upconversion luminescence agent is a promising photocatalyst using sunlight for treating the industry dye wastewater in great force.