An XPS analytical approach for elucidating the microbially mediated enargite oxidative dissolution

Fantauzzi, M.; Rossi, G.; Elsener, B.; Loi, G.; Atzei, D.; Rossi, A.
April 2009
Analytical & Bioanalytical Chemistry;Apr2009, Vol. 393 Issue 8, p1931
Academic Journal
In this work, the microbe-mediated oxidative dissolution of enargite surfaces (Cu3AsS4) was studied on powdered samples exposed to 9K nutrient solution (pH 2.3) inoculated by Acidithiobacillus ferrooxidans initially adapted to arsenopyrite. These conditions simulate the acid mine environment. The redox potential of the inoculated solutions increased up to +0.72 V vs normal hydrogen electrode (NHE), indicating the increase of the Fe3+ to Fe2+ ratio, and correspondingly the pH decreased to values as low as 1.9. In the sterile 9K control, the redox potential and pH remained constant at +0.52 V NHE and 2.34, respectively. Solution analyses showed that in inoculated medium Cu and As dissolved stoichiometrically with a dissolution rate of about three to five times higher compared to the sterile control. For the first time, X-ray photoelectron spectroscopy (XPS) was carried out on the bioleached enargite powder with the aim of clarifying the role of the microorganisms in the dissolution process. XPS results provide evidence of the formation of a thin oxidized layer on the mineral surface. Nitrogen was also detected on the bioleached surfaces and was attributed to the presence of an extracellular polymer substance layer supporting a mechanism of bacteria attachment via the formation of a biofilm a few nanometers thick, commonly known as nanobiofilm. [Figure not available: see fulltext.]


Related Articles

  • Electrical characteristics of postdeposition annealed HfO2 on silicon. Puthenkovilakam, Ragesh; Sawkar, Monica; Chang, Jane P. // Applied Physics Letters;5/16/2005, Vol. 86 Issue 20, p202902 

    Electrical characteristics of ultrathin HfO2 films on p-type silicon (100) substrates were determined by capacitance-voltage and current density-voltage measurements. The as-deposited HfO2 films showed a dielectric constant of ∼22, a leakage current density of 5 A/cm2 and an interface state...

  • Schottky barrier lowering with the formation of crystalline Er silicide on n-Si upon thermal annealing. Reckinger, Nicolas; Xiaohui Tang; Bayot, Vincent; Yarekha, Dmitri A.; Dubois, Emmanuel; Godey, Sylvie; Wallart, Xavier; Larrieu, Guilhem; Łaszcz, Adam; Ratajczak, Jacek; Jacques, Pascal J.; Raskin, Jean-Pierre // Applied Physics Letters;5/11/2009, Vol. 94 Issue 19, p191913 

    The evolution of the Schottky barrier height (SBH) of Er silicide contacts to n-Si is investigated as a function of the annealing temperature. The SBH is found to drop substantially from 0.43 eV for the as-deposited sample to reach 0.28 eV, its lowest value, at 450 °C. By x-ray diffraction,...

  • Energy-band alignment of HfO2/SiO2/SiC gate dielectric stack. Mahapatra, R.; Chakraborty, Amit K.; Horsfall, A. B.; Wright, N. G.; Beamson, G.; Coleman, Karl S. // Applied Physics Letters;1/28/2008, Vol. 92 Issue 4, p042904 

    The band alignment of HfO2/SiO2/SiC gate dielectric stack has been investigated by x-ray photoelectron spectroscopy and electrical characterization. Two types of valence band offsets are observed in the stack layer; the smaller value of 1.5 eV corresponds to the HfO2/SiC band offset while the...

  • Mobility enhancement in amorphous InGaZnO thin-film transistors by Ar plasma treatment. Kang, Jung Han; Namkyu Cho, Edward; Eun Kim, Chang; Lee, Min-Jung; Jeong Lee, Su; Myoung, Jae-Min; Yun, Ilgu // Applied Physics Letters;6/3/2013, Vol. 102 Issue 22, p222103 

    The effects of Ar plasma treatment on the back-channel of amorphous InGaZnO (a-IGZO) thin-film transistors are investigated. A decrease in metallic ion-oxygen bonding in the Ar plasma-treated a-IGZO channel layer was observed by X-ray photoelectron spectroscopy (XPS) depth profile analysis. An...

  • Reaction of oxygen plasma active species with polyethylene. Shikova, T. G.; Rybkin, V. V.; Titov, V. A.; Ho-Suk Choi // High Energy Chemistry;Sep2006, Vol. 40 Issue 5, p351 

    The composition of the polyethylene surface upon treatment in an oxygen plasma and its afterglow was studied by attenuated total reflectance IR spectroscopy and X-ray photoelectron spectroscopy. The oxidation of the surface at the lowest destruction rates was attained upon simultaneous action of...

  • Fifty years of x-ray photoelectron spectroscopy. Alov, N. // Journal of Analytical Chemistry;Mar2005, Vol. 60 Issue 3, p297 

    The history of development, current status, and prospects for x-ray photoelectron spectroscopy are considered upon the fifty years of the method.

  • Surface modification using a novel type I hydrophobin HGFI. Sen Hou; Xinxin Li; Xiaoyu Li; Xi-Zeng Feng; Rui Wang; Chen Wang; Lei Yu; Ming-Qiang Qiao // Analytical & Bioanalytical Chemistry;Jun2009, Vol. 394 Issue 3, p783 

    Surface wettability conversion with hydrophobins is important for its applications in biodevices. In this work, the application of a type I hydrophobin HGFI in surface wettability conversion on mica, glass, and poly(dimethylsiloxane) (PDMS) was investigated. X-ray photoelectron spectroscopy...

  • Three-dimensional nonwoven scaffolds from a novel biodegradable poly(ester amide) for tissue engineering applications. Hemmrich, Karsten; Salber, Jochen; Meersch, Melanie; Wiesemann, Ute; Gries, Thomas; Pallua, Norbert; Klee, Doris // Journal of Materials Science: Materials in Medicine;Jan2008, Vol. 19 Issue 1, p257 

    Biodegradable polyesters are established biomaterials in medicine due to their chemical characteristics and options for material processing. A main problem, however, is the release of acid degradation products during biodegradation with severe local pH-drops and inflammatory reactions....

  • Threshold photoelectron spectroscopy of benzene up to 26.5 eV. Yencha, Andrew J.; Hall, Richard I.; Avaldi, Lorenzo; Dawber, Grant; McConkey, Andrew G.; MacDonald, Michael A.; King, George C. // Canadian Journal of Chemistry;Jun2004, Vol. 82 Issue 6, p1061 

    The threshold photoelectron spectrum of benzene has been recorded up to 26.5 eV photon energy under high-resolution conditions using synchrotron radiation and employing the penetrating-field threshold electron collection method. By means of a direct comparative study with a recent HeI...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics