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Advances in bioleaching of copper and nickel from electronic waste using Acidithiobacillus ferrooxidans: evaluating daily pH adjustment
, Article Chemical Papers ; Volume 74, Issue 7 , 2020 , Pages 2211-2227 ; Yaghmaei, S ; Sharif University of Technology
Springer
2020
Abstract
Abstract: The waste stream of electrical and electronic equipment is three times faster than other municipal waste streams. Recycling of electronic waste is necessary for both reducing environmental pollution and saving natural ores. Bioleaching is known as an efficient technology for metal leaching. In most of the previous studies on the bioleaching of electronic waste, the pH of the process was adjusted daily under the optimal pH of the bacterium growth. Using acid causes increasing process costs and unsustainability of the process. In this work, the effect of daily pH adjustment on the bioleaching efficiency of electronic waste using adapted Acidithiobacillus ferrooxidans was studied....
Bacterial leaching of low-grade ZnS concentrate using indigenous mesophilic and thermophilic strains
, Article Hydrometallurgy ; Volume 85, Issue 1 , 2007 , Pages 59-65 ; 0304386X (ISSN) ; Yaghmaei, S ; Vossoughi, M ; Jafari, A ; Roostaazad, R ; Turunen, I ; Sharif University of Technology
2007
Abstract
In this study low-grade sphalerite has been treated by the bioleaching process using native cultures of Acidithiobacillus ferrooxidans and Sulfobacillus thermosulfido-oxidans in order to determine the ability of these bacteria to the leaching of zinc. The effects of bacterial strain, pH, temperature, pulp density, iron precipitation, and initial concentration of ferric iron on the zinc leaching were evaluated. The bioleaching experiments were carried out in shake flasks at pH 1.5, 180 rpm, 33 °C and 60 °C for mesophilic and thermophilic bacteria, respectively. Compared with the use of laboratory reference strains or control conditions, zinc recovery from the respective concentrate was...
Design of Anaerobic Digestion for Solid Waste Treatment
, M.Sc. Thesis Sharif University of Technology ; Shayegan, Jalaleddin (Supervisor)
Abstract
In this project, performance of anaerobic digestion of organic waste in liquid phase has been investigated in an experimental process. Thus, the objective of this study was to optimize the organic loading rates, temperature and mixing of anaerobic digestion to the treatment of municipal solid wastes. To achieve this, the pilot scale experiment was conducted in 70l, fully mixed reactor. The start-up process was established over a period of 2 months. Starting the digestion in two stages was done with two different feed stocks, in which the feed stock of the first stage was star and in the second stage vegetables were considered as the organic waste. Experiment was investigated in mesophilic...
Thermal Simulation of Bioheap
, Ph.D. Dissertation Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
Nowadays, because of drastically decrease of copper sulfide ore’s grade, and difficulties in leaching of them, new processes of copper production like bioleaching technique become significant. Finding the optimal conditions for bioleaching, require investing a lot of time and cost. Computer simulation is useful in this case. Temperature, affects the kinetics of dissolution reactions, type and growth rate of bacteria, and finally, rate and amount of recovery of valuable copper metal from ores, so determination of temperature within the bioheap is very important. Thermophiles are better than mesophiles in chalcopyrite bioleaching and in the range of 55 to 65 degree centigrade, thermophiles...
Effects of temperature and mixing modes on the performance of municipal solid waste anaerobic slurry digester 09 Engineering 0907 Environmental Engineering 09 Engineering 0904 Chemical Engineering
, Article Journal of Environmental Health Science and Engineering ; Volume 17, Issue 2 , 2020 , Pages 1077-1084 ; Shayegan, J ; Sharif University of Technology
Springer
2020
Abstract
Purpose: Anaerobic digestion is a promising technology for simultaneous treatment of biodegradable organic matter of municipal solid waste (MSW) and production of renewable energy. Mixing modes and temperature have influences on biogas production in anaerobic digesters treating MSW. Therefore, in this study, digester was operated at different modes of mixing and temperatures to obtain design criteria. Methods: The experiments were carried out in a semi-continuous digester. In the first part of the investigation, temperature was set at 25, 28, 31 and 34 °C. During this step, digester content was mixed in an intermittent mode by mechanical mixers. In the second part of the study, mixing...
Modeling of uranium bioleaching by Acidithiobacillus ferrooxidans
, Article Annals of Nuclear Energy ; Volume 43 , May , 2012 , Pages 13-18 ; 03064549 (ISSN) ; Safdari, J ; Roosta Azad, R ; Zokaei Kadijani, S ; Sharif University of Technology
2012
Abstract
In this paper, a mathematical model for the mesophilic bioleaching of uraninite is developed. The case of constant temperature, pH, and initial ore concentration is considered. The model is validated by comparing the calculated and measured values of uranium extraction, ferric and ferrous iron in solution, and cell concentration. Good fits of the model were obtained, while the values of the parameters were within the range expected. New rate expressions were used for the iron precipitation and uranium leaching rates. The rates of chemical leaching and ferric precipitation are related to the ratio of ferric to ferrous in solution. The fitted parameters can be considered applicable only to...
Leaching of a zinc ore and concentrate using the Geocoat™ technology
, Article Minerals Engineering ; Volume 24, Issue 1 , 2011 , Pages 64-69 ; 08926875 (ISSN) ; Petersen, J ; Roostaazad, R ; Hosseini, S ; Mohammad Mousavi, S ; Najafi, A ; Vasiri, A. K ; Sharif University of Technology
Abstract
In this study, the Geocoat™ technology was used for the extraction of zinc from a mineral concentrate obtained from the Kooshk mine (Yazd, Iran) by a culture dominated by the mesophilic bacterium Acidithiobacillus ferrooxidans in a packed column bioreactor. A low grade sphalerite ore was used as support for the concentrate coating. During the 100 days of leaching pH, Fe3+, Fetotal, microbial population density and zinc extraction were measured. The final zinc extraction from concentrate and low grade support was 97% and 78%, respectively, and it was found that leaching from the support does not proceed significantly before leaching from the coating is completed
Efficiency of copper bioleaching of two mesophilic and thermophilic bacteria isolated from chalcopyrite concentrate of Kerman-Yazd regions in Iran
, Article Scientia Iranica ; Volume 14, Issue 2 , 2007 , Pages 180-184 ; 10263098 (ISSN) ; Yaghmaei, S ; Vossoughi, M ; Jafari, A ; Sharif University of Technology
Sharif University of Technology
2007
Abstract
A mesophilic iron oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated (33°C) from a typical chalcopyrite copper concentrate of the Sarcheshmeh Copper Mine in the region of Kerman located in the south of Iran. In addition, a thermophilic iron oxidizing bacterium, Sulfobacillus spp., has been isolated (60°C) from the Kooshk Lead and Zinc Mine near the city of Yazd in the mid-west region of Iran. The variation of pH, ferrous and ferric concentration and cell growth on the time and effects of some factors, such as temperature and initial ferrous concentration, on the bioleaching of chalcopyrite concentrate obtained from Sarcheshmeh Copper Mine, were investigated. Bioleaching...
Anaerobic degradation of molasses stillage in a pilot UASB reactor
, Article Scientia Iranica ; Volume 12, Issue 3 , 2005 , Pages 255-261 ; 10263098 (ISSN) ; Torkian, A ; Hakimjavadi, M ; Azimi, E ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
The feasibility of a mesophilic anaerobic treatment of an alcohol distillery wastewater (beet molasses stillage) was studied in a 1300 I Upflow Anaerobic Sludge Blanket (UASB) reactor for a period of 180 days. The system was seeded with 600 L of mesophilic anaerobic sludge harvested from the bottom of a dairy anaerobic lagoon. Nutrients were added to acidified effluent and after adjusting the pH in an equalization tank, the system was fed with a diluted effluent containing COD in the range of 1000-11000 mg/L at 30°C. Initially, the system had an OLR of 1 kg COD m-3 d-1 and upflow velocity was maintained at 0.6 m/h (HRT= 6 h) throughout the study. A gradual increase in OLR, through increased...
Naphthalene metabolism in Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic microorganism
, Article Chemosphere ; Volume 72, Issue 6 , 2008 , Pages 905-909 ; 00456535 (ISSN) ; Vossoughi, M ; Ardestani, S. K ; Sharif University of Technology
2008
Abstract
The thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, originally isolated in our laboratory from a petroindustrial wastewater contaminated soil in Iran, grows at 50 °C on a broad range of hydrocarbons. Transformation of naphthalene by strain TSH1 which is able to use this two ring-polycyclic aromatic hydrocarbon (PAH) as a sole source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that strain TSH1 initiates its attack on naphthalene by dioxygenation at its C-1 and C-2 positions to give...
The effects of Fe(II) and Fe(III) concentration and initial pH on microbial leaching of low-grade sphalerite ore in a column reactor
, Article Bioresource Technology ; Volume 99, Issue 8 , 2008 , Pages 2840-2845 ; 09608524 (ISSN) ; Yaghmaei, S ; Vossoughi, M ; Roostaazad, R ; Jafari, A ; Ebrahimi, M ; Chabok, O. H ; Turunen, I ; Sharif University of Technology
2008
Abstract
In this study the effects of initial concentration of Fe(II) and Fe(III) ions as well as initial pH on the bioleaching of a low-grade sphalerite ore in a leaching column over a period of 120 days with and without bacteria were investigated. Four different modifications of medium were used as column feed solutions to investigate the effects of initial concentration of Fe(II) and Fe(III) ions on zinc extraction. The experiments were carried out using a bench-scale, column leaching reactor, which was inoculated with mesophilic iron oxidizing bacteria, Acidithiobacillus ferrooxidans, initially isolated from the Sarcheshmeh chalcopyrite concentrate (Kerman, Iran). The effluent solutions were...