Publications by authors named "A Guezennec"

Article Synopsis
  • The H2020 project CROCODILE investigated the recovery of cobalt (Co) from oxidized ores using a process called reductive bioleaching, focusing on reducing Fe(III) to Fe(II) to improve dissolution rates.
  • The study involved two main steps: sustained biomass growth through aerobic bio-oxidation of sulfur, followed by anaerobic reduction of Fe(III) utilizing a microbial consortium.
  • Results showed that increasing biomass concentration significantly enhanced the Fe(III) bioreduction rate, with continuous mode testing achieving up to 20 mg·L·h, indicating that optimizing these reaction rates is crucial for effective bioleaching processes.
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Within the European research project NEMO, a bioleaching strategy was developed for efficient metal extraction from bioleach residue currently heap-leached at Sotkamo (Finland) that still contains sulphidic minerals and valuable metals (Ni, Zn, Co, Cu). The strategy of gradually increasing the solid content with 5% steps allowed the adaptation of the consortium up to 20% (w/w) solid content, with efficient metal dissolution and same dominant bacteria. Largest proportions of Sulfobacillusthermosulfidooxidans while Eh increased suggested it to be most involved in iron oxidation.

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Bioleaching is a promising strategy to recover valuable metals from spent printed circuit boards (PCBs). The performance of the process is catalyzed by microorganisms, which the toxic effect of PCBs can inhibit. This study aimed to investigate the capacity of an acidophilic iron-oxidizing culture, mainly composed of , to oxidize iron in PCB-enriched environments.

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Pyrite-bearing coal wastes are responsible of the formation of acid mine drainage (AMD), and their management to mitigate environmental impacts is a challenge to the coal mine industry in Europe and worldwide. The European CEReS project sought to develop a generic co-processing strategy to reuse and recycle coal wastes, based on removal of AMD generating potential through bioleaching. Chemolitoautotrophic iron- and sulfur-oxidizing microbial consortia were enriched from a Polish coal waste at 30 °C and 48 °C, but not 42 °C.

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As spent printed circuit boards (PCBs) are among the most valuable components in waste electrical and electronic equipment (WEEE), their recovery makes economic and strategic sense. However, their composition varies considerably depending on the location, year and type of appliance in which they were used. Developing new treatment processes requires representative sampling of spent PCBs from large samples and accurate determination of their raw material composition.

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