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The performance of γ-Fe 2 O 3 as sorbent for H 2 S removal at low temperatures (20−80°C) was investigated. First, γ-Fe 2 O 3 /SiO 2 sorbents with a three-dimensionally ordered macropores (3DOM) structure were successfully prepared by a colloidal crystal templating method. Then, the performance of the γ-Fe 2 O 3 -based material, e.g., reference γ-Fe 2 O 3 and 3DOM γ-Fe 2 O 3 /SiO 2 sorbents, for H 2 S capture was compared with that of α-Fe 2 O 3 and the commercial sorbent HXT-1 (amorphous hydrated iron oxide). The results show that γ-Fe 2 O 3 has an enhanced activity compared to that of HXT-1 for H 2 S capture at temperatures over 60°C, whereas α-Fe 2 O 3 has little activity. Because of the large surface area, high porosity, and nanosized active particles, 3DOM γ-Fe 2 O 3 /SiO 2 sorbent shows the best performance in terms of sulfur capacity and utilization. Moreover, it was found that moist conditions favor H 2 S removal. Furthermore, it was found that the conventional regeneration method with air at high temperature was not ideal for the composite regeneration because of the transmission of some amount of γ-Fe 2 O 3 to α-Fe 2 O 3 . However, simultaneous regeneration by adding oxygen in the feed stream allowed the breakthrough sulfur capacity of FS-8 to increase up to 79.1%, which was two times the value when there was no O 2 in the feed stream.

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