The abundant iron sulfide mineral pyrite has been shown to catalytically produce hydrogen peroxide (H2O2) and hydroxyl radical (.OH) in slurries of oxygenated water. Understanding the formation and fate of these reactive oxygen species is important to biological and ecological systems as exposure can lead to deleterious health effects, but also environmental engineering during the optimization ...

in this research work, the zinc extraction was investigated, using bioleaching process from a low grade zinc concentrate which was produced from the accumulated flotation tailings. zinc content was initially upgraded to 11.97% by flotation process. bioleaching experiments were designed and carried out by a mixed culture of acidithiobacillus ferrooxidans, acidithiobacillus thiooxidans, leptospir...

Iron pyrite (FeS(2)) is a naturally abundant and nontoxic photovoltaic material that can potentially make devices as efficient as silicon-based ones; however existing iron pyrite photovoltaic devices contain thermodynamically unstable FeS(2) film surfaces that lead to low open circuit voltages. We report the rational synthesis of phase pure, highly crystalline cubic FeS(2) nanocrystals (NCs) us...

Earth-abundant iron pyrite (FeS2) shows great potential as a light absorber for solar cells and photodetectors due to their high absorption coefficient (>10(5) cm(-1)). In this paper, high-quality phase-pure and single crystalline pyrite nanocrystals were synthesized via facile, low-cost, and environment friendly hydrothermal method. The molar ratio of sulphur to iron and the reaction time play...

At the industrial scale, bioleaching of metal sulfides includes two main technologies, tank leaching and heap leaching. Fluctuations in temperature caused by the exothermic reactions in a heap have a pronounced effect on the growth of microbes and composition of mixed microbial populations. Currently, little is known on the influence of pre-colonized mesophiles or moderate thermophiles on the a...

The interaction strength of progressively longer oligomers of glycine, (Gly), di-Gly, tri-Gly, and penta-Gly, with a natural pyrite surface was directly measured using the force mode of an atomic force microscope (AFM). In recent years, selective activation of abiotically formed amino acids on mineral surfaces, especially that of pyrite, has been proposed as an important step in many origins of...

This paper describes studies on the recovery of metals from spent hydro-processing catalyst using mixed acidophilic culture in presence of pyrite. This culture was initially grown in the 9K medium (absence of 9 g/L Fe(II)) where ferrous sulphate (FeSO4) was replaced by pyrite, and then applied in this bioleaching study. Bacterial action on pyrite catalysed the formation of ferric ion (Feþ3), pr...

Multiple sulphur (S) isotope ratios are powerful proxies to understand the complexity of S biogeochemical cycling through Deep Time. The disappearance of a sulphur mass-independent fractionation (S-MIF) signal in rocks <~2.4 Ga has been used to date a dramatic rise in atmospheric oxygen levels. However, intricacies of the S-cycle before the Great Oxidation Event remain poorly understood. For ex...

Understanding the stability and reactivity of iron sulfide phases is key to developing predictive capabilities for assessing their corrosion and catalytic activity. The differences between the free surface and the bulk interior of such phases are of particular importance in this context. Here, we employ density functional theory to investigate the formation energetics and electronic structure o...

Water chemical analysis of 100 springs from the Orco and the Tinée valleys (Western Italy and Southern France) and a 7 year groundwater chemistry monitoring of the 5 main springs were performed. All these springs drain from crystalline rock slopes. Some of these drain from currently active gravitational slope deformations. All groundwaters flowing through presently unstable slopes show anomalie...