|
| |
|
| |
|
| |
|
|
Evolution of Point-To-Plane Nanosecond Discharge in Deionized Water
Šimek, Milan ; Pongrác, Branislav ; Člupek, Martin ; Babický, Václav ; Lukeš, Petr
We employed techniques of time-resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water. Fast risetime high-voltage pulses (duration of 5 ns and amplitude of ~110 kV) applied in a point-to-plane electrode geometry produced micro-discharges either periodically or in a single-shot regime. Time resolved ICCD images evidence typical streamer-like branched filamentary morphology while emission spectra show a broad-band continuum evolving during the first few nanoseconds followed by the well-known HI/OI atomic lines (tens of ns).
|
|
| |
|
| |
|
|
Application of Pulsed Electric Field on Bacteria
Kadlec, Tomáš ; Babický, Václav ; Člupek, Martin ; Vrbová, M.
Electrical discharges in a water solution cause several processes. e.g., generation of UV radiation, free radicals, and a shockwave, pulse electric field (PEF) takes place too. The PEF was studied separately to achieve better understanding of this complex process. PEF treatment is chemical-free process affecting microbes. An experimental device for PEF treatment was constructed. Solution containing microbial culture of Bacillus subtilis was treated.
|
|
|
Role of UV radiation, solution conductivity and pulse repetition frequency in the bactericidal effects during pulse corona discharge in water
Špetlíková, E. ; Janda, V. ; Lukeš, Petr ; Člupek, Martin
Inactivation of bacteria Escherichia coli and Enterococcus faecalis by the pulsed corona discharge in liquid phase has been investigated. The reactor with point to plate geometry of electrodes was used for generation of the discharge in liquid phase. The effects of the solution conductivity and the pulse repetition frequency on the bacterial inactivation have been determined. Better efficiency of inactivation was observed for both types of bacteria with the increasing solution conductivity and the pulse repetition frequency since E. faecalis was more sensitive to these changes then E. coli. The role of UV radiation emitted by the electrical discharge in the overall bacterial efficiency was evaluated in dependence on the solution conductivity using UV light transparent spectrometric cell. It was determined that UV radiation contributes about 40% to the overall inactivation of bacteria by the discharge.
|
|
|
Degradace nonylfenolu impulsním elektrickým výbojem ve vodě
Tothová, I. ; Janda, V. ; Lukeš, Petr ; Člupek, Martin ; Babický, Václav
Degradation of technical mixture of nonylphenol by the pulsed corona discharge in water has been investigated. It was shown that non-thermal plasma generated by the discharge can effectively remove nonylphenol from water. Degradation of nonylphenol followed first order kinetics. The removal efficiency was dependent on the solution conductivity, while a higher degradation was obtained with higher conductivity. Oxidation of nonylphenol by OH radical attack was proposed as possible mechanism of degradation by the discharge in water.
|
|
|
Elektrické výboje pro využití při čištění vody
Lukeš, Petr ; Člupek, Martin ; Babický, Václav ; Tothová, I. ; Vykouk, T. ; Říhová -Ambrožová, J. ; Janda, V.
Non-equilibrium plasma generated by electrical discharges in liquids initiate various chemical and physical processes that can be potentially utilized in different environmental, biological or medical applications. Depending on the type of the discharge and the input energy these processes include high electric field, ultraviolet radiation, overpressure shock waves and, of particular importance, formation of various reactive chemical species. It has been demonstrated that these physical and chemical processes are capable to inactivate or degrade various microorganisms and chemical compounds dissolved in water. In this presentation an overview of basic principles of electrical discharges in water will be given with particular emhasis to the pulsed (electrohydraulic) discharges, the physical and chemical effects initiated by these discharges in water and their utilization for water treatment applications.
|
guest ::
