Evaluation of photocatalytic selectivity of Ag/Zn modified molecularly imprinted TiO2 by multiwavelength measurement

In this paper, Ag/Zn-MIP-TiO2 was prepared by sol-gel method, and the imprinted molecule was ethyl p-hydroxybenzoate. To study the properties of the Ag/Zn-MIP-TiO2 on the photocatalytic activity, these factors were investigated: the effects of the dosage of Ag and Zn, the amount of imprinted molecules, the calcination temperature and time, then the capture of active substances. Besides, the selectivity of Ag/Zn-MIP-TiO2 was investigated in three aspects: UV-vis multi-wavelength spectral integral area change, specific group absorbance change and traditional reaction kinetic parameter change. The selectivity coefficients of the three angles are 8.55,1.47 and 6.77. And the selectivity factors are 4.12,1.02 and 4.81, indicating that Ag/Zn-MIP-TiO2 has high selectivity. Furthermore, its selectivity is not only for the specific characteristic groups on the target pollutants, but for the integrated target pollutants. From the perspective of materials, Ag/Zn-MIP-TiO2 is 100% anatase with a lower band gap and a larger specific surface area. As a molecularly imprinted polymer, the active sites on the surface make it have selective recognition function. The results of photocatalytic experiments are as follows: the optimum Ag and Zn ratio is Ti: Ag:Zn = 100:1:0.75 (molar ratio); the best molecular weight of imprint is Ti:MIP = 5:1; the finest calcination temperature is 500 degrees C; the optimum calcination time is 2 h; the removal rate of ethyl p-hydroxybenzoate degraded by photocatalysis for 2 h is 99.1%; the main active substance of the photocatalytic reaction is.OH. (C) 2019 Elsevier B.V. All rights reserved.