Preprint Article Version 1 This version is not peer-reviewed

Bioelectrochemical Changes During the Early Stages of Chalcopyrite Interaction with Acidithiobacillus thiooxidans and Leptospirillum sp.

Version 1 : Received: 21 July 2017 / Approved: 21 July 2017 / Online: 21 July 2017 (17:31:25 CEST)

A peer-reviewed article of this Preprint also exists.

López-Cázares, I.; Patrón-Soberano, O.A.; García-Meza, J.V. Bioelectrochemical Changes during the Early Stages of Chalcopyrite Interaction with Acidithiobacillus Thiooxidans and Leptospirillum sp.. Minerals 2017, 7, 156. López-Cázares, I.; Patrón-Soberano, O.A.; García-Meza, J.V. Bioelectrochemical Changes during the Early Stages of Chalcopyrite Interaction with Acidithiobacillus Thiooxidans and Leptospirillum sp.. Minerals 2017, 7, 156.

Journal reference: Minerals 2017, 7, 156
DOI: 10.3390/min7090156

Abstract

A bioelectrochemical study of charge transfer in the biofilm/chalcopyrite interface was performed to investigate the effect of surficial sulfur reduced species (SRS), as non-stochiometric compounds or polysulfides (Sn2-), and elemental sulfur (S0) on a biofilm structure during the earliest stages (1, 12 and 24 h) of chalcopyrite biooxidation by A. thiooxidans alone and adding Leptospirillum sp. The surface of massive chalcopyrite electrodes was exposed to the bacteria, which were analyzed electrochemically, spectroscopically, and microscopically. At the studied earlier times, charge transfer and significant differences in the biofilm structure were detected, depending on the presence of Leptospirillum sp. acting on A. thiooxidans biofilms. Such differences were a consequence of a continuous chalcopyrite pitting and promoting changes in biofilm hydropathy. A. thiooxidans modifies the reactive properties of SRS and favors an acidic dissolution, which shifts into ferric when Leptospirillum sp. is present. A. thiooxidans allows H+ and Fe3+ diffusion, and Leptospirillum sp. allows surpassing the charge transfer (reactivity) barrier between the mineral interface and the ions. The observed changes of hydropathy on the interface are associated to ions and electrons activity and transfer. Finally, a model of S0 biooxidation by A. thiooxidans alone or with Leptospirillum sp., is proposed.

Subject Areas

Sulfur reduced species; Biofilms; Chalcopyrite, Biooxidation; Hydrophobicity

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