J Starosvetsky

Publications of J Starosvetsky

• TiO(2) P-25 anatase rapid precipitation from water by use of struvite formation.

  Authors: I Blumberg, J Starosvetsky, D Bilanovic, R Armon

  Journal of colloid and interface science. 03/2009;

  UV(360nm) irradiation of TiO(2) P-25 nanoparticle in water suspension is used for photocatalytic mineralization of pollutants or inactivation of microorganisms. Removal of TiO(2) particles from largeUV(360nm) irradiation of TiO(2) P-25 nanoparticle in water suspension is used for photocatalytic mineralization of pollutants or inactivation of microorganisms. Removal of TiO(2) particles from large volumes of water following photocatalytic process is problematic due to their nano-size. So far no chemical methods are available for TiO(2) rapid precipitation while filtration or centrifugation is not feasible because of high cost and limited performance. In the present study TiO(2) was rapidly precipitated from water suspension by formation of the mineral struvite. Addition of Mg, P, and NH(4)(+) at stochiometric rates of 1:1:1 at pH>8.3 resulted in TiO(2) entrapment into struvite formed flocs and rapid precipitation. Struvite sludge formed and precipitated was observed under HSEM revealing TiO(2) entrapment into struvite mineral.

• Sol-gel applications in environmental biotechnology.

  Authors: R Armon, C Dosoretz, J Starosvetsky, F Orshansky, I Saadi

  Journal of biotechnology. 12/1996; 51(3):279-85.

  Sol gel process was applied for three different applications in environmental biotechnology: (1) thin, fluorescein diacetate-doped sol-gel film made possible epifluorescent microscopic examination ofSol gel process was applied for three different applications in environmental biotechnology: (1) thin, fluorescein diacetate-doped sol-gel film made possible epifluorescent microscopic examination of adsorbed Escherichia coli CN13 cells without additional staining: (2) Thiobacillus thiooxidans cell-free extract entrapped into sol-gel matrix displayed oxidative activity on H2S in liquid medium; and (3) two media (E. coli (EC) and sulfate-reducing bacteria (SRB)) were doped into sol-gel and used to enumerate environmental samples for E. coli and sulfate-reducing bacteria, by the most probable number (MPN) method. The comparison of the modified method with the standard enumeration method revealed very good correlation. The sol-gel MPN method is sensitive, saves times, and the substrate can be prepared and stored long-term at room temperature (up to 1 year).

• Effect of iron exposure in SRB media on pitting initiation

  Authors: D. Starosvetsky, O. Khaselev, J. Starosvetsky, R. Armon, J. Yahalom

  Corrosion Science.

  Pitting corrosion of iron (99.9%) in Sulphate-reducing bacteria (SRB) media containing 0.09–0.30 g/l sulphides and 0.1–5.0 g/l [Cl−] was studied. Iron electrode immersed in SRB media undergoes fastPitting corrosion of iron (99.9%) in Sulphate-reducing bacteria (SRB) media containing 0.09–0.30 g/l sulphides and 0.1–5.0 g/l [Cl−] was studied. Iron electrode immersed in SRB media undergoes fast activation and numerous active sites formed on the surface. Depending on exposure time, pitting was initiated at different potentials. After short period (<2 h) in open circuit potential, when active sites were still exist on the surface, pitting occurred at the potential range of −0.60 to −0.55 V (SCE). Extended exposures resulted in more stable passivity of iron and the pitting potential shifted to positive values. Pit initiation mechanism at the various exposure periods is discussed.

• Identification of microbiologically influenced corrosion (MIC) in industrial equipment failures

  Authors: J. Starosvetsky, D. Starosvetsky, R. Armon

  Engineering Failure Analysis.

  The present study demonstrates different approaches towards MIC identification in three real cases of technological equipment failures.In the first case the failure of carbon steel heat exchanger asThe present study demonstrates different approaches towards MIC identification in three real cases of technological equipment failures.In the first case the failure of carbon steel heat exchanger as a result of tubes, lids, tube sheets, and connection pipes clogging was investigated. Chemical analysis of cooling water and precipitates, as well laboratory screening of deposits for bacteria, revealed that activity of iron-oxidizing bacteria present in cooling water led to heat exchanger blockage.The second case is related to MIC detection on floating roofs made of magnesium–aluminum alloy following a 3-weeks hydro-test. Corrosion tests carried out on the original and sterilized water used in hydro-test confirmed MIC process.In the third case the potential of MIC occurrence in engine cooling system made of cast aluminum alloy and filled with 20% ethylene glycol coolant solution was evaluated. The simulation tests allowed determining the real causes of the severe corrosion attack of examined system, including MIC high probability.