Abiotic reduction of 4-chloronitrobenzene to 4-chloroaniline in a dissimilatory iron-reducing enrichment culture.
4-chloronitrobenzene (4-Cl-NB) was rapidly reduced to 4-chloroaniline with half-lives of minutes in a dissimilatory Fe(III)-reducing enrichment culture. The initial pseudo-first-order rate constants at 25 degrees C ranged from 0.11 to 0.19 per minute. The linear Arrhenius correlation in a temperature range of 6 to 85 degrees C and the unchanged reactivity after pasteurization indicated that the nitroreduction occurred abiotically. A fine-grained black solid which was identified as poorly crystalline magnetite (Fe(3)O(4)) by X-ray diffraction accumulated in the enrichments. Magnetite produced by the Fe(III)-reducing bacterium Geobacter metallireducens GS-15 and synthetic magnetite also reduced 4-Cl-NB. These results suggest that the reduction of 4-Cl-NB by the enrichment material was a surface-mediated reaction by dissimilatory formed Fe(II) associated with magnetite.
Heijman
C G
CG
Limnological Research Center, Swiss Federal Institute for Environmental Science and Technology (EAWAG), 6047 Kastanienbaum, Switzerland.
Holliger
C
C
Glaus
M A
MA
Schwarzenbach
R P
RP
Zeyer
J
J