Promoting Effect of the Core-Shell Structure of MnO2@TiO2 Nanorods on SO2 Resistance in Hg0 Removal Process

Sorbent of αMnO2nanorods coating TiO2shell (denoted as αMnO2-NR@TiO2) was prepared to investigate the elemental mercury (Hg0) removal performance in the presence of SO2. Due the core-shell structure, αMnO2-NR@TiO2has a better SO2resistance when compared to αMnO2nanorods (denoted as αMnO2-NR). Kinetic studies have shown that both the sorption rates of αMnO2-NR and αMnO2-NR@TiO2, which can be described by pseudo second-order models and SO2treatment, did not change the kinetic models for both the two catalysts. In contrast, X-ray photoelectron spectroscopy (XPS) results showed that, after reaction in the presence of SO2, S concentration on αMnO2-NR@TiO2surface is lower than on αMnO2-NR surface, which demonstrated that TiO2shell could effectively inhibit the SO2diffusion onto MnO2surface. Thermogravimetry-differential thermosgravimetry (TG-DTG) results further pointed that SO2mainly react with TiO2forming Ti(SO4)O in αMnO2-NR@TiO2, which will protect Mn from being deactivated by SO2. These results were the reason for the better SO2resistance of αMnO2-NR@TiO2.Keywords:core-shell structure;αMnO2nanorods;elemental mercury removal;SO2resistance