Adhesion of Acidithiobacillus Caldus and Leptospirillum Ferriphilum on Pyrite and their Effect on Surface Properties of Sulfide Minerals

2009 ◽  
Vol 71-73 ◽  
pp. 449-452
Author(s):  
G. Gu ◽  
Li Jun Su ◽  
Guan Zhou Qiu ◽  
Y. Hu
Keyword(s):  
Surface Properties ◽  
Isoelectric Point ◽  
Sulfide Minerals ◽  
Ferrous Ion ◽  
Bacterial Cells ◽  
Leptospirillum Ferriphilum ◽  
Acidithiobacillus Caldus ◽  
Ft Ir ◽  
Bacterial Adsorption ◽  
Strong Ability

Acidithiobacillus caldus and Leptospirillum ferriphilum cells grown in different energy substances (ferrous ion, sulfur and pyrite) were used. The adhesion of A. caldus and L. ferriphilum cells on pyrite and their effect on pyrite surface properties were studied by adsorption, zeta-potential and FT-IR methods, and the corrosion images of pyrite interaction with bacteria were examined using atomic force microscopy. Research showed that pyrite isoelectric point (IEP) after interaction with bacterial cells shifted towards cells isoelectric point, and the shift degree in case of interaction with A. caldus was observed to be much more pronounced than for interaction with L. ferriphilum, which can be due to higher affinity of A. caldus towards pyrite. The FT-IR spectra of pyrite treated with bacterial cells revealed the presence of the cell functional groups signifying cells adsorption. Although the adsorption density of A. caldus on pyrite was higher than that of L. ferriphilum, L. ferriphilum with strong ability to oxidize ferrous ion showed better leaching efficiency than A. caldus with strong ability to oxidize sulfur for pyrite leaching. The results demonstrated that more important of indirect action (L. ferriphilum) than direct action (A. caldus) on pyrite.Introduction Bacterial adsorption to minerals is an initial step in bacterial leaching for metal recovery [1]. It has been reported that bacterial adhesion is dependent not only on the biochemical properties of the organism but also on the interfacial properties of the various interfaces existing in a bioleaching system[2].The bacteria-mineral interactions result in the changes of their surface properties. The elucidation of their alternate will be beneficial for bioleaching processes. Both Acidithiobacillus caldus and Leptospirillum ferriphilum are known for their ability to inhabit acidic environments and derive energy from oxidation of inorganic substances with natural occurrence in ore deposits and acid mine drainage and high affinity towards sulfide minerals [3-5]. In this work, the alterations of surface properties of pyrite after interaction with L. ferriphilum and A. caldus are studied, and the changes in surface properties caused by bacterial adsorption are discussed with reference to bioleaching behavior of pyrite.

Effects of Leptospirillum ferriphilum and Acidithiobacillus caldus on surface properties of pyrrhotite

2009 ◽  
Vol 100 (1-2) ◽  
pp. 72-75 ◽  
Author(s):  
Guohua Gu ◽  
Kaile Zhao ◽  
Guanzhou Qiu ◽  
Yuehua Hu ◽  
Xiaojun Sun
Keyword(s):  
Surface Properties ◽  
Leptospirillum Ferriphilum ◽  
Acidithiobacillus Caldus

Investigation of Controlled Redox Potential with Pyrite during Chalcopyrite Bioleaching by Mixed Moderately Thermophiles

2017 ◽  
Vol 262 ◽  
pp. 281-284
Author(s):  
Xiao Tao Huang ◽  
Jun Wang ◽  
Hong Bo Zhao ◽  
Min Gan ◽  
Rui Liao ◽  
...  
Keyword(s):  
Redox Potential ◽  
Ferrous Ion ◽  
Copper Extraction ◽  
Ferrous Ions ◽  
Sem Images ◽  
Leptospirillum Ferriphilum ◽  
Acidithiobacillus Caldus ◽  
High Copper ◽  
Constant Ph

Various methods of controlling redox potential (ORP) with electrochemical bioreactor and others have been investigated to increase copper extraction of chalcopyrite in bioleaching,but less attention has been paid to reducing ferric to ferrous ions. Therefore, in this work, the redox potential of chalcopyrite bioleaching system in the presence of mixed moderately thermophiles containing Leptospirillum. ferriphilum,Acidithiobacillus. caldus and Sulfobacillus.thermosulfidooxidans has been controlled by pyrite. It was found that at a constant pH of 2.0, the addition of pyrite can reduce ferric to ferrous ion to a large extent, and the lower ORP values can be obtained. Bioleaching experiments indicated that the time for adding pyrite caused different bioleaching behaviors of chalcopyrite. The high copper extraction can be obtained by added pyrite at a low ORP values (<420 mV vs. Ag/AgCl). The XRD tests and SEM images showed that the amounts of formed jarosite increased as the pyrite addition, and the loose and porous jarosite can be found at low ORP values.

scholarly journals F-doping of nanostructured ZnO: a way to modify structural, electronic, and surface properties

2020 ◽  
Vol 22 (20) ◽  
pp. 11273-11285 ◽  
Author(s):  
Elisabeth Hannah Wolf ◽  
Marie-Mathilde Millet ◽  
Friedrich Seitz ◽  
Frenio A. Redeker ◽  
Wiebke Riedel ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Surface Properties ◽  
Surface Acidity ◽  
Ft Ir

The structure, electronic properties, and surface acidity of polycrystalline ZnO are modified using F2(g). The amount of F incorporated influences the samples' properties, which were studied using, e.g., FT-IR, XPS, TEM, NMR, and microcalorimetry.

Changes in Cell Surface Properties of Shiga Toxigenic Escherichia coli by Quercus infectoria G. Olivier

2009 ◽  
Vol 72 (8) ◽  
pp. 1699-1704 ◽  
Author(s):  
SUPAYANG PIYAWAN VORAVUTHIKUNCHAI ◽  
SAKOL SUWALAK
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Surface Properties ◽  
Cell Surface Hydrophobicity ◽  
Ethanolic Extract ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Cell Surface Properties ◽  
E Coli ◽  
Quercus Infectoria

The effects of Quercus infectoria (family Fagaceae) nutgalls on cell surface properties of Shiga toxigenic Escherichia coli (STEC) were investigated with an assay of microbial adhesion to hydrocarbon. The surface of bacterial cells treated with Q. infectoria exhibited a higher level of cell surface hydrophobicity (CSH) toward toluene than did the surface of untreated cells. With 50% ethanolic extract, the CSH of the three strains of STEC O157:H7 treated with 4× MIC of the extract resulted in moderate or strong hydrophobicity, whereas at 2× MIC and MIC, the CSH of only one strain of E. coli O157:H7 was significantly affected. The 95% ethanolic extract had a significant effect on CSH of all three strains at both 4× MIC and 2× MIC but not at the MIC. The effect on bacterial CSH was less pronounced with the other STEC strains. At 4× MIC, the 50% ethanolic extract increased the CSH of all non-O157 STEC strains significantly. At 2× MIC and 4× MIC, the 95% ethanolic extract affected the CSH of E. coli O26:H11 significantly but did not affect E. coli O111:NM or E. coli O22. Electron microscopic examination revealed the loss of pili in the treated cells. The ability of Q. infectoria extract to modify hydrophobic domains enables this extract to partition the lipids of the bacterial cell membrane, rendering the membrane more permeable and allowing leakage of ions and other cell contents, which leads to cell death. Further studies are required to evaluate the effects of Q. infectoria extract in food systems or in vivo and provide support for the use of this extract as a food additive for control of these STEC pathogens.

Surface properties of copper-sulfide minerals with sodium-hydrosulfide activation

2020 ◽  
Vol 156 ◽  
pp. 106530 ◽  
Author(s):  
Hidekazu Matsuoka ◽  
Kohei Mitsuhashi ◽  
Masanobu Kawata ◽  
Tatsuya Kato ◽  
Chiharu Tokoro ◽  
...  
Keyword(s):  
Surface Properties ◽  
Copper Sulfide ◽  
Sulfide Minerals ◽  
Sodium Hydrosulfide

scholarly journals FT-IR spectroscopic characteristics of differently cultivated Escherichia coli

2009 ◽  
Vol 26 (No. 6) ◽  
pp. 458-463 ◽  
Author(s):  
Z. Filip ◽  
S. Hermann ◽  
K. Demnerová
Keyword(s):  
Escherichia Coli ◽  
Ir Spectra ◽  
Cell Mass ◽  
Bacterial Cells ◽  
Cultural Conditions ◽  
Spectroscopic Characteristics ◽  
Nitrogen Concentrations ◽  
Ft Ir ◽  
Well Differentiated ◽  
Ir Spectroscopic

FT-IR spectra were recorded of <i>Escherichia coli</i> cell mass with the aim of obtaining spectral traits possibly useful in a rapid detection and characterisation of this indicator bacterium. A well differentiated spectrum was obtained from the cell mass harvested in a stationary phase of growth, e.g., after 24 h, from a minimum nutrient broth. The cell mass, harvested either earlier or grown in nutrient solutions which contained an enhanced carbon or nitrogen concentrations delivered somewhat different IR spectra, apparently due to a higher content of nucleic acid components as related to other structural constituents of bacterial cells. Consequently, the FT-IR spectra of <i>E. coli</i>, although rather rapidly to collect, seem only capable of delivering useful and reproducible information if the cell mass is obtained under standardised cultural conditions.

Thermo-mechanical and surface properties of POSS reinforced structurally different diamine cured epoxy nanocomposites

RSC Advances ◽  
2014 ◽  
Vol 4 (85) ◽  
pp. 45433-45441 ◽  
Author(s):  
K. Sethuraman ◽  
P. Prabunathan ◽  
M. Alagar
Keyword(s):  
Bisphenol A ◽  
Surface Properties ◽  
Nmr Spectra ◽  
Epoxy Nanocomposites ◽  
H Nmr ◽  
Ft Ir ◽  
C Nmr

In the present study three structurally different diamines namely bisphenol-A based ether diamine, octane diol based ether diamine, and capron based diamine were synthesized and characterized using FT-IR, 1H-NMR and 13C-NMR spectra.

New polyurethane materials from renewable resources: synthesis and characterization

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Doina Macocinschi ◽  
Daniela Filip ◽  
Stelian Vlad
Keyword(s):  
Surface Properties ◽  
Renewable Resources ◽  
Tensile Tests ◽  
Cellulose Derivative ◽  
Alternative Methods ◽  
Synthesis And Characterization ◽  
Cellulose Derivatives ◽  
Domain Structures ◽  
Ft Ir ◽  
Mechanical Tensile

AbstractIn the present study new types of polyurethane-cellulose derivative biomaterials based on urethane prepolymers functionalized with hydroxypropylcellulose are presented. The aim of the present study is to obtain materials with better haemocompatibility, biocompatibility and amphiphilic microphase-separated domain structures. The outcome of remarkable chemical versatility characteristic to polyurethane materials combined with polymers derived from nature like cellulose derivatives resulting in bulk and surface properties is evidenced by means of different techniques like DSC, TGA, FT-IR, AFM and mechanical tensile tests. The influence of various factors on the developed morphologies and the microstructural changes is investigated. Both polyester and polyether macrodiols have been used to prepare these polyurethanes. The aim of this study is to find also alternative methods for improving biostability while maintaining the excellent biocompatibility and other properties.

scholarly journals Stochasticity of Bacterial Attachment and Its Predictability by the Extended Derjaguin-Landau-Verwey-Overbeek Theory

2011 ◽  
Vol 77 (11) ◽  
pp. 3757-3764 ◽  
Author(s):  
Teck Wah R. Chia ◽  
Vu Tuan Nguyen ◽  
Thomas McMeekin ◽  
Narelle Fegan ◽  
Gary A. Dykes
Keyword(s):  
Stainless Steel ◽  
Physicochemical Properties ◽  
Surface Properties ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Initial Ratio ◽  
Content Type ◽  
Initial Inoculum ◽  
Serovar Typhimurium ◽  
Attachment Process

ABSTRACTBacterial attachment onto materials has been suggested to be stochastic by some authors but nonstochastic and based on surface properties by others. We investigated this by attaching pairwise combinations of twoSalmonella entericaserovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each ofS. entericaserovar Typhimurium,S. entericaserovar Infantis, orS. entericaserovar Virchow (all with similar physicochemical and attachment abilities) in ratios of 0.428, 1, and 2.333 onto glass, stainless steel, Teflon, and polysulfone. Attached bacterial cells were recovered and counted. If the ratio of attached cells of eachSalmonellaserovar pair recovered was the same as the initial inoculum ratio, the attachment process was deemed stochastic. Experimental outcomes from the study were compared to those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Significant differences (P< 0.05) between the initial and the attached ratios for serovar pairs containingS. Sofia S1296a for all different ratios were apparent for all materials. ForS. Sofia S1635-containing pairs, 7 out of 12 combinations of serovar pairs and materials had attachment ratios not significantly different (P> 0.05) from the initial ratio of 0.428. Five out of 12 and 10 out of 12 samples had attachment ratios not significantly different (P> 0.05) from the initial ratios of 1 and 2.333, respectively. These results demonstrate that bacterial attachment to different materials is likely to be nonstochastic only when the key physicochemical properties of the bacteria were significantly different (P< 0.05) from each other. XDLVO theory could successfully predict the attachment of some individual isolates to particular materials but could not be used to predict the likelihood of stochasticity in pairwise attachment experiments.

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