Flame-Made High-Capacity and High Efficient Nanomaterial Wo3-Ceox-Cuo/Tio2 for Mercury Adsorption

Abstract

High-concentration mercury capture at high temperatures is a big challenge for cement clinker production during the periodical shutdown period of raw meal mill. This study synthesized nanomaterials WO3-CeOx-CuO/TiO2 for mercury removal by both wet impregnation and flame synthesis. The performance of the synthesized sorbents is evaluated for mercury removal at 450 °C, which is above the typical temperature at raw meal shutdown conditions. It is found that the adsorption efficiency of the flame-synthesized sorbent remains above 95% after 30 days of absorption, while the sorbent synthesized by wet impregnation gets saturated after 50 hours. To understand the adsorption mechanism, the physicochemical properties of the sorbents including surface area, pore volume and average pore diameter, phase composition, morphology, valence states of surface elements are characterized by N2 adsorption isotherm, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) separately. The results show that the flame-synthesized sorbent has a larger specific surface area and smaller primary particle sizes than the sorbent by wet impregnation. In addition, Cu atoms are dispersed in the flame-synthesized sorbent while CuO clusters are supported on CeO2 in the sorbent by wet impregnation. Based on the XPS results, it can be found that the oxidizing species is the adsorbed molecular oxygen from environment for flame-synthesized sorbent but surface active oxygen (Oβ) is consumed for the sorbent synthesized by the impregnation method.

Keywords: nano materials, flame synthesis, elemental mercury, Adsorption, CuO/CeO2