Removal of hydrogen sulfide by layered double hydroxide loaded biochar in dynamic adsorption experiment

Biochar supported Zn-Al-Fe layered double hydroxide (LDH@BC) was synthesized by in-situ method for removal of H 2 S in dynamic adsorption experiment. The characterization by XRD , FT-IR, and SEM indicated that LDHs uniformly grew on the surface of BC and formed a porous structure, which facilitated the passage of gas and overcome the aggregation of LDHs. The influence factors such as ratio of BC/LDH, water vapor, initial concentration, temperature, and ratio of Al/Fe were investigated. The results showed that as LDH@BC composite possessed BC/LDH=2 and Al/Fe=1/3, the removal of H 2 S revealed a better efficiency under H 2 S concentration of 1000 mg/m 3 and temperature of 180°C, and the removal efficiency was over 80% after 60 min. The presence of water vapor has less than a 10% effect on the removal of H 2 S. The composite after removal of H 2 S was investigated by XRD, FT-IR, SEM, and XPS , and mechanisms of H 2 S removal by LDH@BC were proposed. In regeneration experiment, the presence of water vapor reconstructed part of destroyed LDHs, which possessed high reuse efficiency and decline was less than 20%. The favorable adsorption performance provided a promising strategy for H 2 S removal.