FENTON-LIKE SOIL REMEDIATION CATALYZED BY NATURALLY OCCURRING IRON MINERALS

摘要

The ability of the iron minerals hematite and magnetite to catalyze the decomposition of hydrogen peroxide(H_2 O_2) and initiate the Fenton-like oxidation of pentachlorophenol(PCP) was investigated in batch, bench-scale systems in which PCP was spiked onto silica sand. Pentachlorophenol degradation was documented in silinca sand-mineral-H_2 O_2 systems by the release of choloride and the loss of total organic carbon. The most efficient oxidation stichiometry was the magnetite-catalyzed reaction over the first 8 h with 490 mol H_2 O_2 consumed/mol PCP degraded. After 8 h, the peroxide efficiency decreased significantly; amorphous iron hydroxide formation on the magnetite surface may have catalyzed the decomposition of H_2 O_2 to oxygen species other than hydroxyl radicals. Mineral-catalyzed Fenton-like treatment in two natural soils was demonstrated after spiking the soils with PCP; the contaminant was degraded with no iron addition. The oxidation stoichiometry in the two soils was 1,200 adn 2,930 mol H_2 O_2 consumed/mol PCP degraded.