LAUSR

A novel carbon-based sorbent was prepared from FeSO 4 -flocculated sludge by one-step pyrolysis. The characterization results indicated that multiple Fe 2 O 3 and sulfur species (S 2 2− and polysulfide) existed over this sludge-derived sorbent. Its performance on Hg 0 removal from syngas was evaluated. The sorbent from the sludge pyrolyzed at 710 ℃ could achieve around 86 % Hg 0 removal efficiency at 150 ℃ under simulated syngas (400 ppm H 2 S, 10 ppm HCl, 20 vol% H 2 , 30 vol% CO, 8 vol% H 2 O and N 2 ). H 2 S and HCl exhibited a promoting effect on Hg 0 removal, whereas CO, H 2 and H 2 O inhibited Hg 0 removal. The analysis of adsorption kinetics manifested that Hg 0 adsorption over the sorbent was better described by pseudo-second-order kinetic model, implying that it was a chemisorption process. The Hg 0 removal under N 2 condition was due to the reaction between absorbed Hg 0 and Fe 3+ –O or S 2 2− /polysulfide over the sorbent surface. In the presence of H 2 S, multiple sulfur species was produced by the reaction of adsorbed H 2 S with Fe 3+ –O. The increased sulfur species (S 2 2− and polysulfide) greatly promoted the formation of HgS. The sorbent has good prospect in engineering applications because of its good Hg 0 removal performance, low cost and facile preparation process. Graphic Abstract