Research Watch: EDTA metal solubilization

1998 ◽  
Vol 32 (1) ◽  
pp. 49A-49A
Keyword(s):  
Metal Solubilization

Studies on Microbial Leaching of Heavy Metals from Municipal Sludge

1990 ◽  
Vol 22 (12) ◽  
pp. 229-238 ◽  
Author(s):  
R. D. Tyagi ◽  
D. Couillard ◽  
F. T. Tran
Keyword(s):  
Ammonia Nitrogen ◽  
Filter Press ◽  
Vacuum Filter ◽  
Continuous Stirred Tank Reactor ◽  
Microbial Leaching ◽  
Anaerobically Digested Sludge ◽  
Air Lift Reactor ◽  
Solid Liquid ◽  
Air Lift ◽  
Metal Solubilization

A comparative study between continuous stirred tank reactor (CSTR) with cell recycle and air-lift reactor was carried out in 30 1 capacity reactors for metal solubilization from anaerobically digested sludge. In CSTR at a residence time of 0.75 day, supplementing the feed sludge with 4 g/l of FeSO4.7H2O, using 20% sludge recycle and adjusting pH of the feed sludge to 4.5 resulted in following metal solubilization : 91% Cu, 94% Zn,, 93% Mn, 67% Cd, 67% Ni, 8% Cr, and 7% Pb. At 0.75 day retention time metals were solubilized to the recommended level in CSTR as well as in air-lift reactor. The treated sludge is easy to filter in plates filter press, centrifugation, or vacuum filter. The sludge nutrients do not seem to be diminished as a result of treatment and separation of solid-liquid. The ammonia-nitrogen fraction seems to be transformed in organic nitrogen. The decontaminated sludge produced has less odour.

Effect of pH on metal solubilization from sewage sludge: a neural-net-based approach

1994 ◽  
Vol 21 (5) ◽  
pp. 728-735 ◽  
Author(s):  
Y. G. Du ◽  
T. R. Sreekrishnan ◽  
R. D. Tyagi ◽  
Peter G. C. Campbell
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Neural Net ◽  
Metals Removal ◽  
Complex Biological Process ◽  
System Temperature ◽  
Microbial Leaching ◽  
Metal Solubilization

Microbial leaching for heavy metals removal from municipal sewage sludge is a complex biological process. The ultimate metal solubilization achieved depends on the type of sludge involved (nondigested, aerobically digested or anaerobically digested sludge), the decrease in sludge pH as a result of the leaching operation, and the concentration of metals initially present in the sludge. In addition, the system temperature exerts an indirect but strong influence by its effect on the bacterial growth and acid production process. A neural-net-based model was developed to predict the solubilization of six heavy metals, Cd, Cr, Cu, Ni, Pb, and Zn, from sewage sludge using the bioleaching process. The only input parameters required are the type of sludge, initial metal concentrations in the sludge, and the sludge pH. The model yielded satisfactory predictions of metal solubilization when tested with a number of actual experimental data. Key words: heavy metals, microbial leaching, modelling, neural-net, sewage sludge.

Biomining in the Post-Genomic Age: Advances and Perspectives

2007 ◽  
Vol 20-21 ◽  
pp. 389-400 ◽  
Author(s):  
Carlos A. Jerez
Keyword(s):  
Biofilm Formation ◽  
Microbial Consortium ◽  
Sulfur Compound ◽  
Cell Communication ◽  
Biological Knowledge ◽  
Adaptive Responses ◽  
Oxidative Reactions ◽  
New Findings ◽  
Operations Systems ◽  
Metal Solubilization

Systems Microbiology is a new way to approach research in microbiology. The idea is to treat the microorganism or community as a whole, integrating fundamental biological knowledge with OMICS research (genomics, proteomics, transcriptomics, metabolomics) and bioinformatics to obtain a global picture of how a microbial cell operates in the community. The oxidative reactions resulting in the extraction of dissolved metal values from ores is the outcome of a consortium of different microorganisms. Therefore, this bioleaching community is particularly amenable for the application of Systems Microbiology. As more genomic sequences of different biomining microorganisms become available, it will be possible to define the molecular adaptations of bacteria to their environment, the interactions between the members of the community and to predict favorable or negative changes to efficiently control metal solubilization. Some key phenomena to understand the process of biomining are biochemistry of iron and sulfur compound oxidation, bacteria-mineral interactions (chemotaxis, cell-cell communication, adhesion, biofilm formation) and several adaptive responses allowing the microorganisms to survive in a bioleaching environment. These variables should be considered in an integrative way from now on. Together with recently developed molecular methods to monitor the behavior and evolution of microbial participants during bioleaching operations, Systems Microbiology will offer a comprehensive view of the bioleaching community. The power of the OMICS approaches will be briefly reviewed. It is expected they will provide not only exciting new findings but also will allow predictions on how to keep the microbial consortium healthy and therefore efficient during the entire process of bioleaching.

scholarly journals Evaluation of Heavy Metal Solubilization in Solid Waste Landfill Layers

2001 ◽  
Vol 12 (5) ◽  
pp. 209-218 ◽  
Author(s):  
Takeshi Kurokawa ◽  
Toshiko Komatsu ◽  
Takehiko Fukushima
Keyword(s):  
Heavy Metal ◽  
Solid Waste ◽  
Waste Landfill ◽  
Metal Solubilization

scholarly journals Chelating agents to solubilize heavy metals from Oxisols contaminated by the addition of organic and inorganic residues

2009 ◽  
Vol 66 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Aline Renée Coscione ◽  
Cleide Aparecida de Abreu ◽  
Gláucia Cecília Gabrielli dos Santos
Keyword(s):  
Heavy Metals ◽  
Iron Content ◽  
Chelating Agents ◽  
Chelating Agent ◽  
Soil Samples ◽  
Total Iron ◽  
Southeastern Brazil ◽  
Paulo State ◽  
Specific Metal ◽  
Metal Solubilization

Phytoremediation is an attractive technique for soils contaminated with heavy metals, especially in conjunction with chelating agents to assist metal phytoextraction. Nevertheless, their studies in Brazil are rare. Thus, the objective of the present work was to evaluate the efficiency of the chelating agents EDDS and EDTA for the solubilization of heavy metals from two Oxisols contaminated by organic sources in Jaguariúna (LVJ) and inorganic sources in Paulínia (LVP), São Paulo State, Southeastern Brazil. First, the soil samples were fractionated and the DTPA method was used to quantify heavy metals available forms. The results indicated that the metals were highly available in the soil fractions and could be solubilized by the chelating agents. The soil was suspended for 24 h in a chelating agent solution (EDTA or EDDS) at rates of 0, 250, 500 and 750 mg kg-1 of soil. The concentration of solubilized heavy metals was determined in the resulting solution. The extent of metal solubilization varied according to soil type, the chelating agent added and the specific metal. The amount of iron solubilized, as compared to the total iron (LVJ) was 11% (EDTA) and 19% (EDDS). EDDS solubilized more Cu than EDTA in both soils but more Ni in LVJ, while EDTA solubilized more Zn in both soils but more Cd in LVP. Both EDTA and EDDS may be useful for phytoextraction from soils, although the iron content is an important factor regarding the phytoextraction of heavy metals with chelating agents in Oxisols.

The Effects of EDTA on Metal Solubilization in River Sediment/Water Systems

1997 ◽  
Vol 26 (4) ◽  
pp. 957-966 ◽  
Author(s):  
Stanley J. Gonsior ◽  
Jonathan J. Sorci ◽  
Michael J. Zoellner ◽  
Bryce D. Landenberger
Keyword(s):  
River Sediment ◽  
Water Systems ◽  
Metal Solubilization
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