Revealing insights into the correlations between structure and performance of CrOx monometallic oxide for Hg-0 capture

This study explored the impacts of the synthesis methods on the Hg-0 elimination ability of CrOx adsorbents. In the sample series, the adsorbent prepared using the sol-gel method (labeled as Cr(S)) presented the best Hg0 capture performance; its Hg-0 removal efficiency stayed above 88% at 150 and 200 degrees C and even rose to similar to 97% at 250 degrees C in the entire 5-h Hg-0 capture process. The presence of bountiful surface acid sites aided the sufficient adsorption of Hg-0 and an enhancement in the oxidizability primarily accelerated the subsequent Hg0 oxidation step, which constituted the central reason for the satisfactory Hg-0 capture capability of Cr(S). The Mars-Maessen mechanism assisted in understanding the Hg-0 capture process over Cr(S), in which chemisorption was dominant with Cr6+ and O-alpha serving as the active sites and HgO formed as the final oxidation product.