Reductive Dissolution of Jarosite by Acidiphilium cryptum in Presence of Chelating Agents and Dissolved Iron

摘要

The mutual effects of Acidiphilium cryptum, nine ligands and dissolved iron on jarosite dissolution were studied in a 2(3) full factorial experiment. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) and oxalic acid were able to dissolve jarosite chemically, but bacterial action enhanced this dissolution; from 88 +/- 1, 46 +/- 0 and 36 +/- 0 mu mol/L d to 129 +/- 3, 177 +/- 5 and 106 +/- 14 mu mol/L d, respectively. Oxalate and NTA exhibited a synergistic effect with dissolved iron and bacteria that may be explained by a model in which iron complexes behave as redox mediators in the microbial respiration in which jarosite, a solid substrate, serves as terminal electron acceptor.