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

2017 ◽  
Author(s):  
Irene López-Cázares ◽  
O. Araceli Patrón-Soberano ◽  
J. Viridiana García-Meza
Keyword(s):  
Charge Transfer ◽  
Elemental Sulfur ◽  
Acidithiobacillus Thiooxidans ◽  
Early Stages ◽  
Biofilm Structure ◽  
Reactive Properties ◽  
Acidic Dissolution

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.

Photochemistry of Aqueous Tetrathioantimonate(V)

1995 ◽  
Vol 50 (8) ◽  
pp. 1155-1157 ◽  
Author(s):  
H. Kunkely ◽  
A. Vogler
Keyword(s):  
Charge Transfer ◽  
Absorption Band ◽  
Electronic Spectrum ◽  
Redox Reaction ◽  
Elemental Sulfur ◽  
Metal Charge ◽  
Metal Charge Transfer

The electronic spectrum of [SbS4]3- in 10-3 M NaOH displays an absorption band at λmax = 285 nm which is assigned to a ligand-to-metal charge transfer (LMCT) transition. Upon LMCT excitation [SbS4]3- undergoes an intramolecular redox reaction with the formation of [SbS3]3- and elemental sulfur (φ = 0.11 at λirr = 333 nm).

Changes in biofilm structure during the colonization of chalcopyrite by Acidithiobacillus thiooxidans

2012 ◽  
Vol 97 (13) ◽  
pp. 6065-6075 ◽  
Author(s):  
J. V. García-Meza ◽  
J. J. Fernández ◽  
R. H. Lara ◽  
I. González
Keyword(s):  
Acidithiobacillus Thiooxidans ◽  
Biofilm Structure

scholarly journals An Optical Microbial Biosensor Based on Whole Cell of Acidithiobacillus thiooxidans for Hydrogen Sulfide Determination

2018 ◽  
Vol 6 (1) ◽  
pp. 42
Author(s):  
Odemar Cardoso Silva ◽  
Andréa Medeiros Salgado ◽  
Francisca Pessoa De França
Keyword(s):  
Hydrogen Sulfide ◽  
Elemental Sulfur ◽  
Low Cost ◽  
Acidithiobacillus Thiooxidans ◽  
Bacterial Cells ◽  
Low Oxygen ◽  
Microbial Biosensor ◽  
Biosensor Application ◽  
Good Repeatability ◽  
Low Oxygen Concentration

Due to its corrosive and highly toxic character, the generation of hydrogen sulfide is a serious problem for the environment, human health, and the industry. This paper reported a new and simple methodology for aqueous hydrogen sulfide determination through the development of an optical microbial biosensor. The principle of detection was based on the aerobic and chemolithotrophic metabolism of Acidithiobacillus thiooxidans bacterial cells. Under low oxygen concentration and acidic conditions A. thiooxidans can rapidly oxidize H2S to elemental sulfur. The biochemical formation of elemental sulfur can be spectrophotometrically detected and the increase in absorbance at 620 nm exhibited a linear relationship to an H2S concentration up to 100 mg.L-1. The parameters concerning the analytical performance of the biosensor such as cell harvesting time and pH influence were measured and optimized through the optical absorption value. The biosensor was selective to H2S with no important disturbance by tested species except thiosulfate ion (11.5% error). Biosensor response expressed good repeatability (RSD = 4.46 %) and reproducibility (RSD = 4.66 %). The low cost of cell cultivation and the absence of the immobilization step make feasible the optic biosensor application.

Bioleaching of Orpiment (As2S3) in Absence of Fe3+

2015 ◽  
Vol 1130 ◽  
pp. 363-366
Author(s):  
Guang Ji Zhang ◽  
Qiao Yang ◽  
Chao Yang
Keyword(s):  
Elemental Sulfur ◽  
Sulfide Minerals ◽  
Experimental Results ◽  
Acidithiobacillus Thiooxidans ◽  
Ferric Ion ◽  
Arsenic Sulfide ◽  
Iron Ions ◽  
Mining Tailings ◽  
Planktonic Bacteria

Abstract Orpiment (As2S3) is one of the major arsenic sulfide minerals, which can be dissolved by ferric ion and proton produced by the bacteria, and the main intermediates were polysulfides and elemental sulfur. In this study, two strains (Acidithiobacillus thiooxidans and Acidthiobacillus caldus) were used to bioleach the orpiment without iron ions addition. The experimental results show that both the two strains can grow in the pulp and dissolve the orpiment. In the bioleaching, it was found that pH decreased, the concentration of arsenic increased significantly and no elemental sulfur is detected on the surface of the residuals. At the same time the density of the planktonic bacteria increased obviously. These results indicate that the orpiment can be dissolved by the bacteria easily in absence of Fe3+. This study suggests that the release of arsenic which is from orpiment in the mining tailings can be faster than expected in open air.

Bioleaching of Copper Slag Material

2017 ◽  
Vol 262 ◽  
pp. 61-64 ◽  
Author(s):  
Axel Schippers
Keyword(s):  
Elemental Sulfur ◽  
Copper Slag ◽  
Economic Feasibility ◽  
Copper Recovery ◽  
Processing Route ◽  
Low Grade ◽  
Acidithiobacillus Thiooxidans ◽  
Biological Assays ◽  
Copper Release ◽  
Mineral Phases

Bioleaching is applied mainly for copper recovery from low-grade sulfide ores via heap leaching. The main copper processing route includes pyrometallurgy and the remaining copper slag from smelting may still contain copper in amounts found in the ore. Here bioleaching of copper slag material with a copper content of about 1 % (grain size < 63 µm) and fayalite (Fe2SiO4) und magnetite (Fe3O4) as main mineral phases was tested in aerobic shake flask experiments with a mixed culture of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidiphilium spp..To additionally test for reductive bioleaching, experiments under anaerobic conditions (80% N2, 20% CO2, v/v) with or without addition of elemental sulfur were run. The pH was adjusted to < 3 by addition of sulfuric acid. After the incubation period of more than 50 days at 30°C cell growth was observed in all biological assays. The redox potential was above 800 mV SHE in the aerobic biological assays and dropped to around 500 mV in the chemical control assays as well as in the anaerobic biological and chemical assays. A significant copper bioleaching was observed in the aerobic experiments with 91 % copper release (max. 35 % in the chemical controls). Anaerobic bioleaching experiments did not show a significant copper release, however the release of iron (as iron(II)) and sulfate was much higher than in the abiotic assays and several fold higher than in the classical aerobic bioleaching experiments. Overall the results show that copper bioleaching from slag material is possible, however the economic feasibility needs to be demonstrated.

scholarly journals Performance of Urea-Based Fertilizers Associated With Elemental Sulfur or Polymers on Ammonia Volatilization

2021 ◽  
Vol 13 (4) ◽  
pp. 73
Author(s):  
Odirley Rodrigues Campos ◽  
Edson Marcio Mattiello ◽  
Wedisson Oliveira Santos ◽  
Reinaldo Bertola Cantarutti ◽  
Rafael Coca Cuesta ◽  
...  
Keyword(s):  
Soil Ph ◽  
Ammonia Volatilization ◽  
Elemental Sulfur ◽  
Soil Surface ◽  
Acidithiobacillus Thiooxidans ◽  
Nh3 Volatilization ◽  
Oxidation Rates ◽  
Coated Urea ◽  
Polymer Coated Urea ◽  
Urea Granules

High N-NH3 losses are expected when conventional urea is applied to the soil surface. In order to reduce it, urea granules could be coated with different materials to decrease fertilizer dissolution rate or to stabilize N-NH4+ by acidification. In this study, we investigated the effect of a polymer-coated urea and powdered S0 added to urea, in the presence or absence of a S-oxidizing bacterium (Acidithiobacillus thiooxidans), on soil pH, SO42- availability, NH4+, and NH3 volatilization. Applying S0 before urea and the inoculation with bacteria have promoted the highest S0 oxidation rates. The greater decrease in soil pH occurred when S0 was applied before urea at a higher dose, which also decreased NH3 volatilization by 83% up to 4 days after urea application. However, the decrease in soil pH did not increase the concentration of NH4+, nor did it decrease the accumulated amount of volatilized NH3 over time. The inoculation of A. thiooxidans accelerates S0 oxidation process, but it was insufficient to counteract the H+ consumption by urea hydrolysis. Therefore, the S0 application with urea did not offer chemical protection against NH3 loss, but a physical barrier in the controlled-release urea had less dissolved urea in soil and reduced NH3 losses.

scholarly journals Nutrient availability in phosphate and potassic rocks induced by Acidithiobacillus oxidizing bacteria to produce biofertilizers

2020 ◽  
pp. 250-258
Author(s):  
Emmanuella Vila Nova da Silva ◽  
Newton Pereira Stamford ◽  
Wagner da Silva Oliveira ◽  
Valdomiro Severino de Souza Júnior ◽  
Lusiene Barbosa Sousa ◽  
...  
Keyword(s):  
Nutrient Availability ◽  
Elemental Sulfur ◽  
Initial Time ◽  
Acidithiobacillus Thiooxidans ◽  
Mineralogical Analysis ◽  
Sulfur Bacteria ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Set Up ◽  
Potassic Rocks

Production of conventional fertilizers requires significant energy consumption which increases the price of the product. In recent years, a growing interest on the application of natural products has been shown by public. The aim of this work is to evaluate the effectiveness of the sulfur bacteria Acidithiobacillus thiooxidans to promote mineralogy changes and increase nutrient availability, using phosphate and potassic rocks to produce PK biofertilizers. The study was set up in Petri dishes using 30 g of phosphate rock + 30 g of potassium rock, each rock mixed with elemental sulfur applied at two levels 10% and 20% (3 g and 6 g) in dish. The experiment was conducted in a completely randomized design with eight replications (each rock). The bacterium was inoculated applying 1 ml per g of elemental sulfur. The rocks were incubated during 180 days and mineralogical analysis by XRD and chemical analysis were processed at 30, 60, 120, 150 and 180 days after inoculation. The Acidithiobacillus produced sulfuric acid, which promoted mineralogical changes especially at 180 days after inoculation, compared with the initial time. The inoculation of Acidithiobacillus reduced pH and promoted mineralogical changes in P and K rocks with a significant increase in P and K availability, becoming a viable alternative to plant nutrition instead of soluble PK fertilizers. In addition, it showed great potential for a sustainable agriculture system.

Photoreactivity of Titanocene Pentasulfide

1998 ◽  
Vol 53 (2) ◽  
pp. 224-226 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Charge Transfer ◽  
Electronic Spectrum ◽  
Elemental Sulfur ◽  
Reductive Elimination ◽  
Metal Charge ◽  
Long Wavelength ◽  
Wavelength Absorption ◽  
Metal Charge Transfer

Abstract The electronic spectrum of Cp2TiS5 shows a long-wavelength absorption at λ max = 492 nm which is assigned to the lowest-energy S52- → TiIV ligand-to-metal charge transfer (LMCT) transition. The photolysis of the complex in CH2CI2 leads to the formation of Cp2TiCl2 and elemental sulfur. It is suggested that LMCT excitation initiates a reductive elimination with the extrusion of S5 while the reduced titanocene is reoxidized by the solvent.

scholarly journals Processing of Water Treatment Sludge by Bioleaching

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6539
Author(s):  
Tomasz Kamizela ◽  
Malgorzata Worwag
Keyword(s):  
Water Treatment ◽  
Elemental Sulfur ◽  
High Efficiency ◽  
Incubation Temperature ◽  
Metal Leaching ◽  
Acidithiobacillus Thiooxidans ◽  
Water Treatment Sludge ◽  
Time Intervals ◽  
Experimental Conditions

Biological metal leaching is a technology used in the mining and biohydrometallurgy industries where microorganisms mediate the dissolution of metals and semi-metals from mineral ores and concentrates. The technology also has great potential for various types of metal-rich waste. In this study, bioleaching was used for sludge from water treatment. In addition to checking the applicability of the process to such a substrate, the influence of experimental conditions on the effectiveness of bioleaching of metals with sludge from water treatment was also determined, including sample acidification, addition of elemental sulfur, incubation temperature, and Acidithiobacillus thiooxidans-isolated strain. The measurement of metal concentration and, on this basis, the determination of bioleaching efficiency, as well as pH and oxygen redox potential (ORP), was carried out during the experiment at the following time intervals: 3, 6, 9, 12 days. After the experiment was completed, a mass balance was also prepared. After the experiment, high efficiency of the process was obtained for the tested substrate. The effectiveness of the process for most metals was high (Ca 96.8%, Cr 92.6%, Cu 80.6%, Fe 95.6%, Mg 91%, Mn 99.5%, Ni 89.7%, Pb 99.5%, Zn 93%). Only lower values were obtained for Al (58.6%) and Cd (68.4%).

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