TEXTURE AND STRUCTURE VARIATION OF PEROVSKITE LaFeO3/ZSM-5 DURING HIGH-TEMPERATURE DESULFURIZATION

Perovskite LaFeO 3 /ZSM-5 is synthesized via citrate route for H 2 S removal at high temperatures. It shows good thermal stability after heat treatment at 500–700 ∘ C with respect to slight changes in crystallographic phase and textural property. It presents the optimal desulfurization performance at 600 ∘ C with sulfur capacity of 1017 μ mol S/g and products of S, LaS 2 , and Fe 7 S 8 . Sulfidation at 500 ∘ C yields the same products as sulfidation at 600 ∘ C but displays the lowest sulfur capacity of 408 μ mol S/g. Sulfidation at 700 ∘ C produces La 2 O 2 S, Fe 3 S 4 , and unreacted LaFeO 3 . The activation energy of the sulfidation reaction over LaFeO 3 /ZSM-5 is 109.6 kJ/mol.