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 H2S 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 con-centration, 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 H2S revealed a better efficiency under H2S concentration of 1000 mg/m(3) and temperature of 180C, 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 H2S. The composite after removal of H2S was investigated by XRD, FT-IR, SEM, and XPS, and mechanisms of H2S removal by LDH@BC were proposed. In regen-eration 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 H2S removal.

Automated summary

Biochar supported Zn-Al-Fe layered double hydroxide (LDH@BC) was synthesized for efficient removal of H2S. The LDHs grew uniformly on the surface of BC and formed a porous structure, enabling better gas passage. The optimized LDH@BC composite exhibited over 80% removal efficiency for H2S at a concentration of 1000 mg/m(3) and temperature of 180C.