Bioleaching offers a low-input method of extracting valuable metals from sulfide minerals, which works by exploiting the sulfur and iron metabolisms of microorganisms to break down the ore. Bioleaching microbes generate energy by oxidising iron and/or sulfur, consequently generating oxidants that attack sulfide mineral surfaces, releasing target metals. As sulfuric acid is generated during the process, bioleaching organisms are typically acidophiles, and indeed the technique is based on natural processes that occur at acid mine drainage sites. While the overall concept of bioleaching appears straightforward, a series of enzymes is required to mediate the complex sulfur oxidation process. This review explores the mechanisms underlying bioleaching, summarising current knowledge on the enzymes driving microbial sulfur and iron oxidation in acidophiles. Up-to-date models are provided of the two mineral-defined pathways of sulfide mineral bioleaching: the thiosulfate and the polysulfide pathway.
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http://dx.doi.org/10.1042/EBC20220257 | DOI Listing |
Glob Chang Biol
January 2025
Department of Environmental and Biological Sciences, Faculty of Science, Forestry and Technology, University of Eastern Finland, Kuopio, Finland.
Primary and secondary atmospheric pollutants, including carbon monoxide (CO), carbon dioxide (CO), nitrogen oxides (NO), ozone (O), sulphur dioxide (SO) and particulate matter (PM/PM) with associated heavy metals (HMs) and micro- and nanoplastics (MPs/NPs), have the potential to influence and alter interspecific interactions involving insects that are responsible for providing essential ecosystem services (ESs). Given that insects rely on olfactory cues for vital processes such as locating mates, food sources and oviposition sites, volatile organic compounds (VOCs) are of paramount importance in interactions involving insects. While gaseous pollutants reduce the lifespan of individual compounds that act as olfactory cues, gaseous and particulate pollutants can alter their biosynthesis and emission and exert a direct effect on the olfactory system of insects.
View Article and Find Full Text PDFNat Geosci
December 2024
Department of Earth Sciences, University of Geneva, Geneva, Switzerland.
The sulfur species present in magmatic fluids affect the global redox cycle, the Earth's climate and the formation of some of the largest and most economic ore deposits of critical metals. However, the speciation of sulfur under conditions that are relevant for upper crustal magma reservoirs is unclear. Here we combine a prototype pressure vessel apparatus and Raman spectroscopy to determine sulfur speciation in arc magmatic fluid analogues in situ over a range of geologically relevant pressure-temperature-redox conditions.
View Article and Find Full Text PDFGround Water
January 2025
Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China.
Wetlands, as crucial terrestrial carbon reservoirs, have recently suffered severe degradation due to intense human activities. Lacustrine sediments serve as vital indicators for understanding wetland environmental changes. In the current paper, porewater samples were extracted from lacustrine sediment in three boreholes with a depth of ~75 cm in the Huixian karst wetland, southwest China, to study the chemical and dissolved inorganic carbon (DIC) evolution under anthropogenic influence.
View Article and Find Full Text PDFLangmuir
January 2025
Faculty of Land Resources Engineering, Kunming University of Science and Technology, Kunming 650093, China.
The sulfidization-xanthate flotation process has been used commercially with some success in recovering azurite, but it remains unsatisfactory in terms of the environmental impact and flotation index. To remediate these deficiencies, this study evaluated the flotation performance of sodium trithiocarbonate (NaCS) as a green sulfidizing agent for azurite. Flotation test results demonstrated that NaCS has the same efficacy as sodium sulfide but markedly superior activation performance.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
State Key Lab of Geohazard prevention & Geoenvironment protection, College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China. Electronic address:
Sulfur nanoparticles (SNPs) and their composites are promising for heavy metal adsorption, yet current SNPs often lack surface S, leading to low affinity toward heavy metal and ease of aggregation. Here, we report a simple light-driven method for facile prepare SNPs with surfaces enriched with S and in-situ load them onto graphene oxide (GO) to fabricate GO-S composites. Under illumination, the O generated by photosensitizer phloxine B was able to oxidize S into elemental SNPs.
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