Rare Earth Doping Tio < Sub > 2 < / Sub > The Preparation Of Nanomaterials And The Detection Of Chlorpyrifos And Degradation

World wide pesticide usage has increased dramatically in the past few decades. It has caused the increasing pollution and created a significant threat to the environment and human health. Therefore, it is particularly important to detect and hand of pesticide.With the development of nanotechnology, it has been applied to the detection and handling of pesticides, using tetrabutyl titanate as precursor, metal ions doped TiO2nano-materials was prepared by sol-gel method. It was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible absorption spectra and fluorescence spectraanalysis of the samples and applied to the detection and degradation of the pesticide chlorpyrifos.Eu3+doped titanium dioxide nano-materials was prepared by sol-gel method. The interaction of chlorpyrifos with Eu3+doped titanium dioxide nano-materials was studied. It found that chlorpyrifos to the quenching of the fluorescence of Eu3+-doped titanium dioxide nano-materials. And the quenching was found to obey the Stern-Volmer equation, the rate constant (kq) was1.240×1011L/(mol·s). The quenching mechanism is discussed on the basis of the rate constant as well as the reduction potential of the titanium dioxide and the mechanism of electron transfer has been confirmed by the calculation of free energy change(ΔGet) by Rehm-Weller equation as well as energy level diagram. A new rapid and easy method for detection of pesticides was established. The range of detection was2.5×10-10～2.5×10-7mol/L, the detection limit was3.2×10-11mol/L.Ferric and terbium co-doped titanium dioxide (Fe/Tb-TiO2) photocatalysts, which could degrade chlorpyrifos (CPF) both under UV and sun light irradiation, were prepared by the sol-gel method. It was found that co-doping inhibited the growth of crystalline size and the transformation from anatase to rutile. X-ray diffraction and scanning electron microscope analyses showed that the crystalline size of Fe/Tb-TiO2was in the range of20-30nm. UV-vis spectra revealed that UV absorption range of co-doped titanium dioxide is wider than single-doped titanium dioxide. And the photoreaction based on the prepared samples for photodegradation of5.0mg/L chlorpyrifos solution was examined. The results showed that co-doped titanium dioxide had the highest photoactivity among all as-prepared samples. The improvement of photocatalytic activity was ascribed to the synergistic effects of Fe and Tb co-doping.