Ball-Milling Preparation of La3+/TiO2 Photocatalyst and Application in Photodegradation of PVC Plastics

The fact that the use of a large number of plastic products has brought serious pollution to the environment has always been the focus of global attention. The development of photocatalytic degradable plastics is one of the effective ways to solve the problem of “white pollution”. In this work, La3+ modified TiO2 nanoparticles were prepared by ball milling and characterized. La3+/TiO2 was mixed with Polyvinyl chloride (PVC) plastic to make a photodegradable composite film, and the photodegradation performance and mechanical properties of films were evaluated. The photodegradable films were characterized by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). After 30 h UV irradiation, the weight loss rate of the PVC was only 2.12%, while that of the TiO2/PVC reached 8.94%. The accelerating of the degradation rate was due to the mixing of TiO2 into PVC. As for the La3+/TiO2/PVC composite film, when the mass percentage of La3+/TiO2 was 1.5%, the weight loss rate of La3+/TiO2/PVC sample reached a maximum of 17.78%, which was eight times the degradation rate of PVC and two times the degradation rate of TiO2/PVC. The La3+/TiO2/PVC film showed good photodegradability. La is a transition metal element with a special 4f electronic structure. The reaction mechanism of photodegradation of PVC by the interaction of La3+ and TiO2 were discussed.