外源氧化铁对水稻土甲烷形成的抑制

Suppression of methanogenesis by iron oxides in paddy soil

通过添加不同氧化铁的土壤泥浆厌氧恒温培养实验发现 ,无定形氧化铁和纤铁矿能显著的降低水稻土中的H2 和乙酸浓度 ,并导致甲烷形成被抑制 .易还原氧化铁可使H2 的稳态浓度由对照的 2— 4mg m3 降低到 0 3— 1 0mg m3 ,并使得体系的Gibb’s自由能 (ΔGH)增大到 - 10kJ mol,从而有效地抑制了依赖H2 营养的产甲烷过程 .添加氧化铁同样能消耗体系中的乙酸 ,使乙酸浓度明显低于对照 。

Different iron oxides were added to anoxic incubated paddy slurries.The results showed that the concentrations of hydrogen and acetate reduced remarkablely, and the methane production was inhibited. Ferrihydrite and lepidocrocite may decrease the threshold concentration of H\-2 from 2—4?mg/m 3 to 0 3—1?mg/m 3, and increase the Gibb's free energy values to -10?kJ/mol, which may effectively inhibit hydrogenotrophic methanogenesis. Identically, ferrihydrite and lepidocrocite may also consume acetate in the system, but can not affects slightly on Δ G Ac value of acetoclastic methanogenesis.