Hydrogen Peroxide Decomposition by Pyrite in the Presence of Fe(III)-ligands

作者：Chirita P^*

来源：Chemical and Biochemical Engineering Quarterly, 2009, 23(3): 259-265.

• Hydrogen peroxide
• pyrite
• Fe(III)-ligands
• reaction mechanism

The decomposition of hydrogen peroxide (H(2)O(2)) by pyrite in the presence of Fe(III)-ligands (sulfosalicylate (SSAL), ethylenediaminetetraacetate (EDTA), and phosphate) has been investigated in aqueous acidic media (pH 1) at 25 degrees C. It was found that H(2)O(2) decomposition by pyrite was inhibited by the presence of EDTA, SSAL and phosphate. On the other hand, pyrite oxidation by H(2)O(2) does not seem to be affected by the presence of Fe(III)-ligands. The experimental results demonstrate that H(2)O(2) decomposition in the presence of Fe(III)-ligands is catalyzed by pyrite surface (a heterogeneous process). This process is first order with respect to [H(2)O(2)]. It is expected that the rate-determining step of the reaction mechanism of H(2)O(2) decomposition in the presence of Fe(III)-ligands is one of the following two reactions:
FeHO(2)(2+) -> Fe(2+) + HO(2)(center dot)
Fe(OH)(HO(2))(+) -> Fe(2+) + HO(2)(center dot) + HO(-)
where denotes pyrite surface.

• 出版日期2009-9