Photocatalytic degradation performance of gaseous formaldehyde by Ce-Eu/TiO2 hollow microspheres: from experimental evaluation to simulation.

Abstract

Gaseous formaldehyde present indoors is often in low-medium concentration, as compared to that contained in manufactured products, but still poses great threat to human health. Thus, this work aims to fabricate Ce-Eu/TiO2 hollow microspheres, which showed excellent photocatalytic performance toward formaldehyde. Furthermore, photocatalytical degradation performance of Ce-Eu/TiO2 hollow microspheres toward formaldehyde was investigated. The kinetics of degradation mechanism of gaseous formaldehyde for different concentrations and different temperatures vs time were studied, and the simulation and experimental results were also compared. It was found that formaldehyde concentration had an effect on the degradation process, which was consistent with different kinetics reactions. At low concentration, the degradation rate was decided by the adsorption rate, and no accumulation of adsorbent occurred. This process was consistent with the first-order kinetics law, which was established by L-H dynamics theory and Arrhenius equation. At medium concentration, the degradation process of formaldehyde was controlled by both adsorption and photocatalysis, which was consistent with the power law model. The 3D model of formaldehyde degradation process by Ce-Eu/TiO2 hollow microspheres at different concentrations vs time was established, and the results showed that the simulation equations were in good agreement with the experimental results.