Investigation on the Hg0 adsorption performance of Na2S- and S0-modified ZSM-5 adsorbent

摘要

Abstract In this study, a series of Na2S- and S0-decorated ZSM-5 adsorbents were prepared and their Hg0 adsorption performance was evaluated. Given that S0 and Na2S were co-doped with the mass ratio of S0 to ZSM-5 fixed to 2:1, Hg0 removal efficiency quadruples compared with raw ZSM-5 and reached ca. 100% at 300?°C. Combined with the characterization results, it could be concluded that chemical properties, instead of physical structures, played an important role in Hg0 removal. Among the various gas components, O2, NO, and SO2 made negligible impacts on Hg0 capture over 2:1-S/ZSM-5 adsorbent surface. After recycling four times, Hg0 removal efficiency of 2:1-S/ZSM-5 adsorbent remained higher than 80%, which was indicative of a certain recyclability. Finally, XPS results illustrated that S0 and S2? on 2:1-S/ZSM-5 surface functioned as the active sites for the transformation of Hg0 to HgS, which facilitated the chemisorption process and consequently led to an improved Hg0 capture performance.