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A novel carbon-based sorbent was prepared from FeSO4-flocculated sludge by one-step pyrolysis. The characterization results indicated that multiple Fe2O3 and sulfur species (S22− and polysulfide) existed over this sludge-derived sorbent. Its performance on Hg0 removal from syngas was evaluated. The sorbent from the sludge pyrolyzed at 710 ℃ could achieve around 86 % Hg0 removal efficiency at 150 ℃ under simulated syngas (400 ppm H2S, 10 ppm HCl, 20 vol% H2, 30 vol% CO, 8 vol% H2O and N2). H2S and HCl exhibited a promoting effect on Hg0 removal, whereas CO, H2 and H2O inhibited Hg0 removal. The analysis of adsorption kinetics manifested that Hg0 adsorption over the sorbent was better described by pseudo-second-order kinetic model, implying that it was a chemisorption process. The Hg0 removal under N2 condition was due to the reaction between absorbed Hg0 and Fe3+–O or S22−/polysulfide over the sorbent surface. In the presence of H2S, multiple sulfur species was produced by the reaction of adsorbed H2S with Fe3+–O. The increased sulfur species (S22− and polysulfide) greatly promoted the formation of HgS. The sorbent has good prospect in engineering applications because of its good Hg0 removal performance, low cost and facile preparation process. [ABSTRACT FROM AUTHOR]

The Co‐modified CeO2‐TiO2 catalyst prepared by facile co‐precipitation was used for efficient elemental mercury oxidation in flue gas. Results indicated that Co doping greatly enhanced the activity and SO2 resistance of the CeO2‐TiO2 catalyst. In the presence of 5% O2, 500 ppm NO, 800 ppm SO2 and 3% H2O at 200 °C, the Hg0 removal efficiency of CeCo3/Ti could maintain at about 87% for a relatively long time. Characterizations of catalysts (BET, XRD, Raman spectroscopy, TEM, H2‐TPR, O2‐TPD, XPS, TG‐MS and SO2‐DRIFTS) were carried out to reveal the mechanism of Co modification on the redox ability, SO2 resistance and resultant mercury oxidation removal performance of catalyst. It was found that an interaction of Ce with Co promoted the dispersion of CeO2, increased chemisorbed oxygen concentration, and improved the oxygen storage capacity and the reducibility of catalyst, which was beneficial to the improvement of Hg0 oxidation removal. Hg0 would adsorb onto the catalyst and react with surface active oxygen species replenished by gas‐phase O2 to be oxidized via Mars‐Maessen mechanism. SO2 consumed the surface active oxygen species and resulted in the reduction of Ce4+ to Ce3+, which induced the deactivation of catalyst. The introduced Co in CeO2‐TiO2 catalyst exerted the function of protecting Ce4+ from being poisoned by SO2 and thus promoted the sulfur resistance and Hg0 removal performance of the catalyst in the presence of SO2. [ABSTRACT FROM AUTHOR]