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WO1996032175A2 - Procedes acceleres d'oxydation d'agents contaminants organiques dans des milieux aqueux en recourant a des reactions induites par effet de couronne et a des particules - Google Patents

Procedes acceleres d'oxydation d'agents contaminants organiques dans des milieux aqueux en recourant a des reactions induites par effet de couronne et a des particules Download PDF

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Publication number
WO1996032175A2
WO1996032175A2 PCT/US1996/004797 US9604797W WO9632175A2 WO 1996032175 A2 WO1996032175 A2 WO 1996032175A2 US 9604797 W US9604797 W US 9604797W WO 9632175 A2 WO9632175 A2 WO 9632175A2
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Prior art keywords
particles
corona discharge
corona
activated carbon
voltage
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WO1996032175A3 (fr
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Bruce R. Locke
Wright C. Finney
David R. Grymonpre
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Florida State University
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Florida State University
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Priority claimed from US08/416,393 external-priority patent/US6695953B1/en
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Priority to AU56631/96A priority Critical patent/AU5663196A/en
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Publication of WO1996032175A3 publication Critical patent/WO1996032175A3/fr
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/4608—Treatment of water, waste water, or sewage by electrochemical methods using electrical discharges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/087—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
    • B01J19/088—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
    • C01B15/01—Hydrogen peroxide
    • C01B15/027—Preparation from water
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J2219/0803—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
    • B01J2219/0805—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
    • B01J2219/0845—Details relating to the type of discharge
    • B01J2219/0849—Corona pulse discharge
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/10—Photocatalysts

Definitions

  • the present invention relates to oxidation of organic contaminants in aqueous mediums using corona induced reactions. More particularly, the present invention relates to the use of a source or means other than oxygen, such as iron, in a corona reactor to facilitate the production of hydroxyl radicals from hydrogen peroxide (H 2 ⁇ 2 _) generated by corona discharges in the aqueous medium to significantly enhance the oxidation of organic contaminants in the aqueous mediums. In addition, the present invention relates to the use of such sources or means in combination with oxygen in corona discharge procedures to even further oxidize organic contaminants in aqueous mediums.
  • a source or means other than oxygen such as iron
  • the present invention concerns the addition of particles, such as coarse and/or fine particles, to the aqueous medium in a corona reactor to affect the nature of the properties of the corona discharge, i.e., streamer length, intensity, number of streamers and sparkover voltage, thereby increasing the breakdown voltage (i.e., the maximum voltage prior to sparkover), so that the oxidation of organic contaminants may be accelerated.
  • particles such as coarse and/or fine particles
  • a normal corona discharge is formed when dc or ac high voltage is applied between a non-uniform electrode geometry in a fluid dielectric.
  • An electric corona has a three-dimensional discharge pattern that displays highly localized positive or negative space charge waves. These waves constitute the active region that propagates due to avalanches of electrons present in the high electric field. The electron avalanches are triggered by a photonization mechanism that provides secondary seed electrons.
  • a region of weakly ionized plasma known as the "passive region, " remains along the track of the wave. This region provides the path for the current flow from the high voltage electrode. This current flow provides energy for the advancement of the corona.
  • Pulsed streamer corona technology uses high voltage pulses with very short width, approximately 100-1000 ns. This unique characteristic produces a corona that differs markedly from normal continuous discharge (dc corona), ac discharge, and long-pulse ( ⁇ 1 ms)* corona discharge.
  • dc corona normal continuous discharge
  • ac discharge ac discharge
  • long-pulse ⁇ 1 ms* corona discharge.
  • a pulsed streamer corona discharge has been used for treating gas phase pollutants. See, Clements, I.S. et al.: IEEE Transactions Ind. Appl.. IA-(23):224 (1987).
  • pulsed streamer corona was believed to be much more effective at promoting the reactions leading to desulfurization and dentrification than, for example, electron beam processes. See, Clements, I.S.
  • molecular ozone can selectively react with contaminants through cycloaddition, electrophilic reaction, and nucleophilic reaction with unsaturated aromatic and aliphatic species. See Loire, B. et al.: eds., Ozone in Water Treatment, Applications and Engineering, Lewis Publishers, Chelsea, Michigan (1991).
  • ozone can lead to the formation of hydroxyl radicals. These radicals are highly reactive with a broad range of organic materials,
  • Ozone is known to also have a strong effect on coagulation or flocculation of organic matter.
  • the mechanisms by which ozone facilitate coagulation are not well understood. Indeed there may be several different mechanisms involved that depend upon the characteristics of the waste. See, L encourage, B. et al.: eds., Ozone in Water Treatment, Applications and Engineering, Lewis Publishers, Chelsea, Michigan (1991).
  • a number of alternative processes have been considered and studied for the degradation of organic contaminants in aqueous solutions. See, Ollis, D.F. et al. : Environ. Sci. Technol.. 25(9): 1523 (1991). These include oxidation processes such as UN photolysis, direct ozonation, L encourage, B. et al.: eds., Ozone in Water Treatment, Applications and Engi neering , Lewis Publishers , Chelsea, Michigan (1991), photo-catal ys is ,
  • the present invention alleviates certain of the aforementioned problems and shortcomings of the present state of the art through the discovery of novel methods for degrading organic molecules or contaminants in aqueous mediums.
  • the methods of the present invention are based upon the realization that corona-induced reactions when supplemented are very effective at breaking down organic contaminants in aqueous mediums.
  • the methods of the instant invention are premised upon the realization that sufficient quantities of hydroxyl radicals can be generated from hydrogen peroxide ⁇ -O produced by corona discharge procedures, and preferably pulsed streamer corona discharge procedures, through the use of an effective source or means, other than oxygen, in a corona reactor for oxidizing the organic contaminants in the aqueous mediums to end products, such as C0 2 , H 2 0 and other possible constituents, like HCI.
  • the methods of the present invention are premised upon the realization that the addition of an effective amount of suitable particles to the aqueous solutions in a corona reaction will advantageously affect the nature of the properties of the corona discharge thereby increasing the breakdown voltage (i.e.
  • the breakdown of the organic contaminants present in the aqueous mediums can be significantly enhanced through the use of corona discharge procedures in combination with such sources or means, other than oxygen, which are capable of facilitating the generation of hydroxyl radicals from the H 2 0 2 produced in the aqueous mediums by the corona discharge processes.
  • sources or means includes transition metals, such as iron (ferrous or ferric), manganese, copper, cobalt, uranium, rhenium, and other transition metals, elemental iron, photocatalysts, such as titanium dioxide and silicon dioxide,cadmium sulfide, manganese oxide, magnesium oxide, lead oxide and zinc oxide.
  • any source or means, other than oxygen, which is capable of producing hydroxyl radicals is contemplated by the instant invention. It has also been found in accordance with the methods of the present invention that when oxygen is continuously added to the aqueous mediums in a corona reactor in combination with such sources or means, ozone is formed in-situ by, for example, the pulsed streamer corona, and the breakdown of the organic molecules or contaminants in the aqueous mediums is even further enhanced.
  • the addition of an effective amount of suitable particles to the aqueous medium in a corona reactor uniquely affects the physical characteristics, i.e., streamer length, intensity, number of streamers and sparkover voltage, of the streamer corona discharge.
  • the addition of an effective amount of suitable particles shows increases in the number of streamers, length of the streamers, and the maximum applied voltage that could be applied between the point and plane electrode prior to without thereby increasing the breakdown voltage (i.e., the maximum voltage prior to sparkover).
  • suitable particles include activated carbon, such as powdered activated carbon or granular activated carbon, and/or glass beads. More particularly, such particles may be utilized in the following sizes: 1.) about 75-300 micrometer diameter powder activated carbon;
  • aqueous mediums in a corona reactor which contain an effective amount of powdered activated carbon show an increase in the number of streamers, an increased length in the streamers, and a large increase in the maximum applied voltage that could be applied between the point and plane electrode prior to without, while aqueous mediums in a corona reactor which contain an effective amount of granular activated carbon show increases in maximum applied voltage at sparkover. Notwithstanding, the addition of granular carbon appears to have some qualitative effect on the size and quantity of streamers in comparison to aqueous mediums containing no particles.
  • the results show an increase in measured current when compared to aqueous mediums without any particles; however, there are differences in the streamer size, number and intensity.
  • organic contaminants such as aromatics, like phenol, benzene, toluene, ethylbenzene, xylene, anthracene and phenanthracene, halogenated hydrocarbons, like trichloroethylene, tetrachloroethylene, perchloroethylene and other chlorinated and brominated hydrocarbons, nitrogen-containing compounds, such as nitrobenzene and cyanide, sulfur-containing compounds, such as mercaptans and aliphatic compounds, like hydrocarbons, alcohols and carboxylic acids, in aqueous solutions, such as waste waters.
  • FIGS are illustrative of certain embodiments within the scope of this invention.
  • FIGS. 1(a), (b), (c) and (d) disclose diagrams of chemical reactions and/or transport phenomena. More particularly, FIG. 1(a) illustrates a diagram of chemical reactions and transport phenomena occurring in gas/liquid corona treatment processes, FIG. 1(b) illustrates corona-induced chemical reactions, FIG. 1(c) illustrates propagation reactions, and FIG. 1(d) illustrates termination reactions;
  • FIG. 2 is a schematic of a pulsed streamer corona aqueous solution reactor;
  • FIG. 3 illustrates a rotating spark gap power supply used to supply the pulsed voltage;
  • FIGS. 4(a), (b) and (c) illustrate the breakdown of phenol during corona procedures in the presence and absence of oxygen. More particularly, FIG. 4(a) shows phenol breakdown at pH 3.98 without ( + ) and with oxygen (*), FIG. 4(b) shows phenol breakdown at pH 7.00 without (+) and with oxygen (*), and FIG. 4(c) shows phenol breakdown at pH 9.3 without (+) and with oxygen (*). Control without corona is shown by x.
  • FIGS. 5(a) and (b) illustrates the breakdown of phenol during corona procedures in the presence of iron (Fe ++ ) with and without oxygen and in the presence of phosphate and borate buffer, respectively. More particularly, FIG. 5(a) illustrates the effects of iron addition at low pH with (o) and without (x) oxygen addition. Shown for reference is the data from Figure 4(a). FIG. 5(b) illustrates the effect of phosphate (*) and borate (+) buffer on phenol breakdown.
  • FIG. 6 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor.
  • FIG. 7 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor with and without activated carbon particles.
  • FIG. 8 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor with activated carbon particles.
  • FIG. 9 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor with and without granular activated carbon.
  • FIG. 10 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor with and without 140-200 micrometer diameter glass beads.
  • FIG. 11 illustrates the effects of applied voltage vs. current for 550 ml of deionized water in a pulsed streamer corona discharge reactor with and without 60-100 micrometer diameter glass beads.
  • FIGS embodying the present invention are shown by way of illustration only and not as limitations of the present invention.
  • the principles and features of this invention may therefore be employed in various and numerous embodiments without departing from the scope of the invention.
  • Corona refers to an electrical glow adjacent to the surface of a high voltage conducting electrode within a non-uniform electric field.
  • Corona discharge refers to the ionic and electronic emission from a high voltage corona, characterized by the formation and flow in an electric field between two or more electrodes of positive ions, negative ions, and electrons.
  • Streamer corona discharge refers to a filamentous, normally short-lived electronic pathway or discharge that triggers an electrical breakdown (spark) between two asymmetrical electrodes under a high voltage tension.
  • Pulsed streamer corona discharge refers to a temporally stable, long, brushlike type of streamer corona having a large electron (not ion) component that is produced by repetitively applying a series of very short duration (200 - 2000 ns) high voltage pulses to an asymmetrical electrode geometry.
  • a streamer corona discharge zone defined by spaced electrodes in a point-to-plane geometry is utilized.
  • Other embodiments, such as wire-to-cylinder or wire-to-plane geometries may be utilized.
  • the pulsed streamer corona discharge is produced by a rotating spark gap high voltage pulsed power supply, capable of supplying the reactor discharge electrode with, in this case, high voltage (25 - 40 kV), short duration (200 - 2000 ns), fast rise time (20 - 100 ns), repetitive (60 Hz), electrical pulses.
  • pulsed streamer corona discharge technology used in accordance with the present invention is that it uses a very short pulse width (approximately 1000 ns). This characteristic produces a corona that differs markedly from normal continuous discharge (dc corona), ac discharge, and long pulse corona discharge.
  • dc corona normal continuous discharge
  • ac discharge ac discharge
  • long pulse corona discharge One important consequence of the brief duration of the pulse is that it minimizes power wasted on ionic migration because the mobility of ions is much less than that of electrons. Energetic electrons produce free radicals; ions do not contribute to free radical formation.
  • any effective pulse width such as 100-1000, may be used and contemplated by the methods of the present invention.
  • corona discharge and in particular pulsed streamer corona discharge, in combination with a source or means, other than oxygen, in accordance with the methods of the present invention is effective at breaking down organic contaminants, such as phenol, in aqueous mediums in, for example, an isothermal batch reactor and in a semi-batch reactor.
  • organic contaminants such as phenol
  • iron such as FeSo 4 7H 2 0, as the source, alone or especially in combination with the continuous addition of oxygen, at low pH and high voltage in a pulsed streamer corona discharge procedure using very short pulse widths on the order of about 100-1000 ns is very effective in the degradation of organic contaminants.
  • low pH and high voltage refers to a pH of between about 2 and about 7, and preferably about 4, and a voltage of at least about 20 to about 45 kV or more, respectively. Nevertheless, any effective pH and voltage are contemplated by the methods of the present invention.
  • oxygen in combination with the source or means like iron, such as FeS0 4 7H 2 0, or other equivalent compounds at preferably low pH is found to significantly enhance organic contaminant (phenol) degradation even further. This may be due to the simultaneous occurrence of Fenton's and Hamilton's reactions induced by the corona discharge.
  • the first pathway consists of corona-induced aqueous phase reactions.
  • the second pathway arises from ozone production in the gas phase with subsequent mass transfer into the liquid phase followed by liquid phase ozone reactions.
  • FIG. 1 shows certain of the features present in a gas/liquid pulsed streamer corona treatment process in accordance with this invention. It can be seen in FIG. 1 that in addition to the aqueous phase corona induced reactions, a number of gas and liquid reactions also occur when oxygen is continuously added to the system. As shown in FIG. 1 , the ozone produced in the gas phase is transferred to the liquid phase through the gas/liquid interface. Once in the liquid, it is believed that the ozone leads to a number or reactions that will degrade the contaminants. In accordance with the present invention, these reactions are believed to contribute to the degradation of organic wastes.
  • the sequence of adding or using the sources or means to facilitate the generation of hydroxyl radicals from the corona-produced H 2 0 2 in the aqueous mediums may also impact upon the efficiency and effectiveness of the degradation of the organic contaminants. While the sources or means may be introduced or utilized at any point in the process, it is preferable to add or use the sources or means, especially if it is a compound, such as iron like FeS0 4 7H 2 0, or elemental iron prior to the start of the corona discharge procedure.
  • an effective amount of suitable particles may be added to the aqueous mediums in a corona reactor to increase the breakdown voltage applied, i.e., the maximum voltage prior to sparkover, efficiency of the oxidation of organic contaminants, as indicated herein.
  • the use of the particles may be alone or in combination with other means or sources which are capable of facilitating the generation of hydroxyl radicals from H 2 0 2 produced in the aqueous mediums by the corona discharge process.
  • Exemplary of such sources or means include, as indicated hereinbefore, transition metals, photo-catalysts and/or oxygen.
  • FIG. 2 shows a diagram of a reactor vessel used in accordance with the present invention.
  • a cylindrical plexiglass tube capped on the bottom and having dimensions of about 5 cm inside diameter and about 19 cm high is used.
  • the reactor vessel typically contains approximately 550 ml of solution and is submerged in an outer vessel containing an ice bath in order to keep the temperature constant (approximately 250 * C) during the runs.
  • Pulsed streamer corona treatment of the liquid solution is provided by a high voltage discharge electrode in a point-to-plane geometry.
  • the hollow hypodermic needle point electrode is located along the central axis of the cylindrical reactor approximately 5 cm above the bottom of the vessel.
  • a stainless steel round plate ground electrode is placed at the top of the reactor opposite the needle discharge.
  • a magnetic stirring rod at the bottom of the reactor provides good solution 'mixing in the reactor.
  • a recirculation pump is connected to the reactor via two nylon fittings and 1/8 inch polyethylene tubing to allow for sample withdrawal.
  • 5 ml samples are taken from the reactor vessel at about 20 minute intervals during the course of the runs.
  • Temperature and pH are measured before and after each run.
  • the solution is prepared by dissolving about 2.8-3.0 ml of about 0.5 x 10° M phenol solution in 550 ml of deionized water.
  • Temperature and pH are measured before and after each run.
  • the final phenol concentration in the solution is about 1.00-1.25 mg/1.
  • FeSO*7H 2 0 is added in two runs to give about 9.1 X 10"* and about 8.3 x 10"* M solutions.
  • Sample analysis is performed using a Perkin-Elmer HPI-C with a C-18 column and uv detection set at about 280 nm.
  • Chromatography pump conditions of 1 ml/min and a carrier solvent of about 0.5% acetic acid and about 5.0% acetone are used. Sample analysis is performed immediately after removal from the reactor. Peak height on a chart recorder output from the HPLC is used to determine contaminant concentration after calibration with standard solutions.
  • Pulsed energization of the high voltage discharge electrode is provided by a rotating spark gap power supply, FIG. 3, with a peak voltage (Vp) in the range of about 25-40 kV, pulse width of 500-1000 ns, pulse rise time of 20-100 ns, and a repetition frequency of 60 Hz.
  • Vp peak voltage
  • a dc bias voltage of 0-30 kV is available.
  • the streamer corona propagates outward from the central discharge region located at the tip of the needle point.
  • the fast-rising, short duration voltage pulses produce a very high localized electric field ( — 100 kv/cm) without sparkover. This results in the formation of more intense and uniform streamers.
  • FIGS. 4(a), 4(b) and 4(c) show the breakdown of phenol for various conditions of pH and oxygen addition. At about pH 9.3, FIG. 4(c), the control run with only 0 2 and no discharge shows no phenol breakdown. Approximately 30% breakdown is achieved for all three pH values (3.98, 7.00, 9.32) after 80 minutes when no oxygen is added to the system. A comparison of the degradation of phenol indicates the following trends.
  • FIG. 5(a) A dramatic increase in phenol degradation rate occurs upon the addition of iron to the reactor.
  • the effect of iron addition with and without oxygen is shown in FIG. 5(a). It can be seen that iron has a significant effect on the rate of phenol degradation. With oxygen bubbling through the discharge point, complete breakdown occurs in approximately 20 minutes, and without oxygen (pulsed streamer corona only) breakdown is complete in less than about 40 minutes. This is a significant enhancement compared to the runs when iron is not added to the reactor, as shown in FIGS. 4(a), 4(b) and 4(c). However, the rapid increase in the reaction rate upon the addition of FeS0 4 .7H 2 0 may be attributed to the presence of Fenton's reactions and Hamilton's reactions. When Fe 2+ reacts with H 2 0 2 , hydroxyl radicals are produced. This is known as
  • the catechol produced may further oxidize phenol by a Hamilton's type system, see Sangster, D.F.: Free Radical and Electrophilic Hydroxylation, Chemistry of Hydroxyl group part-I, Interscience Publishers (Edited by Saul Fatal) (1971). Hamilton's reactions requires Fe 3+ , catechol, and H 2 0 2 . See, Sangster, D.F.: Free Radical and Electrophilic Hydroxylation, Chemistry of Hydroxyl group part-I, Interscience Publishers (Edited by Saul Fatal) (1971).
  • ozone formed in the gas phase will transfer into the liquid phase and may lead to the breakdown of the organic species. Direct attack of ozone may result in 1,3 cycloaddition. Ozone may also attack phenol indirectly via hydroxyl radical formation. In aqueous solution, ozone also reacts with water molecules to form hydrogen peroxide, which then decomposes to form hydroxyl radicals.
  • the decomposition of ozone is influenced by pH. See Hoigne, J. : Radiation for a Clean Environment, International Atomic Energy Agency, Vienna Austria, 219-232 (1975). At high pH, the ozone decomposition rate is very rapid while at low pH, ozone is fairly stable, therefore, more hydroxyl radicals are formed at high pH and the phenol breakdown rate would be faster than at low pH values. This is reflected in the data shown in FIGS. 4(a), 4(b) and 4(c). Since the aromatic nucleus of phenol is inert to addition reactions, the major pathway for phenol is not, in general, 1 ,3 dipolar cyclo- addition. It is instead believed to be indirect hydroxyl radical attack.
  • FIG. 2 shows a diagram of a reactor vessel used in accordance with the present invention.
  • the apparatus consists of a 550 ml plexiglass vessel used as a reaction chamber, as indicated in EXAMPLE I. This vessel is closed at both ends and is submerged in an ice bath to approximate isothermal conditions, as further indicated in EXAMPLE I.
  • the electrical discharge is provided at the tip of a hollow hypodermic needle which is connected to a high voltage pulsed power supply (see EXAMPLE I).
  • the corona extends from the needle upwards toward the stainless steel ground plate in a point- to-plane geometry (see EXAMPLE I).
  • the separation distance between the needle tip and ground plate is set at 5 cm (see EXAMPLE I).
  • a magnetic stirrer at the bottom of the vessel provides thorough mixing of the solution (see EXAMPLE I).
  • Two nylon fittings on the side of the vessel are used to take samples for analysis (see EXAMPLE I).
  • Streamer corona is produced by a rotating spark gap high voltage pulsed power supply, capable of supplying the reactor discharge electrode with high voltage (about 20 - 100 kV), short duration, (200 - 1000 ns), fast rise time (20 - 50 ns), repetitive (60 Hz), electrical pulses.
  • the initial trials for this EXAMPLE II consists of control runs of about 550 ml of deionized water only in the pulsed corona reactor.
  • the first control utilizes a fully exposed discharge electrode needle and, the second control employs a needle which is covered with a plastic covering along the needle shaft, leaving only the tip exposed in order to emulate a more true point-to-plan geometry.
  • a second type of particle which is used in the corona, is granular activated carbon (about 6 to 14 mesh, about 3.3 -
  • This second trial is run with concentrations of about 1.0 g, about 2.0 g, and about 5.0 g of carbon per about 550 ml of deionized water.
  • the next set of trials are done by adding powdered activated carbon at concentrations of about 0.5 g, about 1.0 g, about 2.0 g, and about 5.0 g to about 550 ml of deionized water in the pulsed corona reactor.
  • the voltage and current data are present in FIGS. 7 and 8.
  • FIG. 7 all four concentrations of particles and the control trial (with no particles) are plotted.
  • the current at the corona onset voltage of about 20 kV is higher than that for the no-particle control trial.
  • All of the trials with particles appear to show higher numbers of streamers, and longer streamers at given voltages when compared to the control with no particles. These determinations are qualitative by observation and no exact measurements are made. As the concentration of the powdered carbon increases, the quantity and length of streamers also increases for equal voltage applied.
  • FIG. 8 is a plot of current vs.
  • the second set of trials that is tested in the corona reactor is the granular activated carbon. These trials used samples of about 550 ml of deionized water containing concentrations of about 1.0 g, about 2.0 g, and about 5.0 g of carbon.
  • FIG. 9 shows the relationship between the current and voltage for these three granular carbon concentration trials and compares it to the control run without any particles. There were no significant differences between the granular activated carbon runs and the control except for the about 5 g concentration trial.
  • the measured current is slightly higher and the sparkover increased to about 42.5 kV from about 40 kV.
  • the sparkover increased to about 42.5 kV from about 40 kV.
  • a possible reason for the lack of change in the properties of the corona might be that the granular activated carbon particles are difficult to suspend in solution, and vigorous stirring is believed to cause most of the particles to be accelerated outward to the reactor margin, away from the middle of the solution where the high voltage discharge needle is located.
  • the third set of trials is done with two different sizes of glass beads, about 60 - lOO ⁇ m diameter and about 140 - 200 ⁇ m diameter. Again, each of the sizes are evaluated at concentrations of about 1.0 g, about 2.0 g, and about 5.0 g per about 550 ml deionized water in the pulsed corona reactor.
  • the effects of the particles on the current vs. voltage characteristics are shown in FIGS. 10 and 11. At set voltages, there is an increase in current for the smaller sized glass beads and less of a change for the larger sized glass beads compared to the no-particle control.
  • the sparkover voltage is about 37.5 kV for all six of the concentrations and sizes of glass beads.
  • One of the more notable observation for all of these trials is that the streamer size appears to decrease, but the number of streamers appears to increase and they appear to be much more intense and brighter.
  • the particle type having the greatest effect on the sparkover voltage in the reactor is the powdered activated carbon.
  • Addition of powdered activated carbon to the aqueous solution appears to produce more streamers, longer streamers, and increased sparkover voltage.
  • organic contaminants such as phenols
  • the removal of organic contaminants, such as phenols may be accelerated, since the production of hydroxyl radicals, aqueous electrons, and hydrogen peroxide increases with increases in the applied discharge voltage. See,

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Abstract

Nouveaux procédés plus rapides, faisant appel à une décharge par effet de couronne et, de préférence, à une décharge par effet de couronne sous tension élevée à flux pulsé, en combinaison avec une quantité efficace de particules appropriées; pour décomposer des polluants organiques comme le phénole ou le rouge au phénole, dans des milieux aqueux. Il a été découvert, plus particulièrement, que l'addition d'une quantité efficace de particules appropriées à la phase aqueuse dans un réacteur à effet de couronne influe considérablement sur les caractéristiques de la décharge par effet de couronne, c'est-à-dire sur la longueur des flux, leur intensité, leur nombre et la tension disruptive, accroissant ainsi considérablement la tension de claquage (c'est-à-dire la tension maximale avant la tension disruptive), de telle sorte que l'extraction des polluants organiques a pu être acceléré étant donné que la production de radicaux hydroxyl, d'électrons aqueux et de pyroxyl d'hydrogène s'améliore en fonction des accroissements de la tension de décharge appliquée. En conséquence, il a été découvert que l'addition de telles particules au fluide dans le réacteur par effet de couronne entraîne une réduction du temps d'exposition et un accroissement de l'efficacité. Ces procédés peuvent être appliqués dans un réacteur à effet de couronne comportant une électrode plane à la terre suspendue au dessus d'une électrode en pointe d'aiguille creuse branchée à une source de courant haute tension pulsé par un éclateur rotatif.
PCT/US1996/004797 1995-04-06 1996-04-04 Procedes acceleres d'oxydation d'agents contaminants organiques dans des milieux aqueux en recourant a des reactions induites par effet de couronne et a des particules Ceased WO1996032175A2 (fr)

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AU56631/96A AU5663196A (en) 1995-04-06 1996-04-04 Accelerated methods of oxidizing organic contaminants in aqu eous mediums using corona induced reactions and particles th erewith

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US08/416,393 US6695953B1 (en) 1993-11-05 1995-04-06 Accelerated methods of oxidizing organic contaminants in aqueous mediums using corona induced reactions and particles therewith
US08/416,393 1995-04-06

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WO1996032175A2 true WO1996032175A2 (fr) 1996-10-17
WO1996032175A3 WO1996032175A3 (fr) 1996-12-05

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WO1999028015A1 (fr) * 1997-12-03 1999-06-10 Applied Plasma Physics As Procede et appareil de traitement d'effluents par un plasma non thermique
WO2001016031A3 (fr) * 1999-09-01 2001-09-20 Univ Abertay Dundee Procede
WO2004041725A3 (fr) * 2002-11-05 2004-08-26 Aquapure Technologies Ltd Procede et systeme de purification et de desinfection d'eau
KR100448632B1 (ko) * 1998-12-21 2004-09-13 주식회사 포스코 플라즈마를 이용한 대기오염물질 처리장치 및 그 방법
WO2016103246A1 (fr) * 2014-12-23 2016-06-30 Oxypro Ltd. Procédé et dispositif de génération de peroxyde d'hydrogène
US10138562B2 (en) 2016-05-18 2018-11-27 Yefim Riskin Method for conversion of water into hydrogen peroxide and converter
WO2019082174A1 (fr) * 2017-10-23 2019-05-02 Oxypro Ltd. Procédé et dispositif de conversion d'eau en peroxyde d'hydrogène
RU2773011C1 (ru) * 2020-07-17 2022-05-30 Михаил Иванович Будник Устройство получения экологически чистого раствора пероксида водорода для стимуляции роста и развития растений

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DE3922383C2 (de) * 1988-08-11 1994-06-09 Grimma Masch Anlagen Gmbh Verfahren zur Vernichtung toxischer Abprodukte und Vorrichtung zur Durchführung des Verfahrens
US5277773A (en) * 1989-12-27 1994-01-11 Exxon Research & Engineering Co. Conversion of hydrocarbons using microwave radiation
US5043080A (en) * 1990-02-26 1991-08-27 Solarchem Enterprises Inc. Treating contaminated effluents and groundwaters
US5236672A (en) * 1991-12-18 1993-08-17 The United States Of America As Represented By The United States Environmental Protection Agency Corona destruction of volatile organic compounds and toxics

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US6254764B1 (en) 1996-11-05 2001-07-03 E/P Technologies Method for dissociating materials
WO1998019788A3 (fr) * 1996-11-05 1998-08-06 E P Technologies Inc Procede et appareil permettant de dissocier des materiaux
WO1999028015A1 (fr) * 1997-12-03 1999-06-10 Applied Plasma Physics As Procede et appareil de traitement d'effluents par un plasma non thermique
KR100448632B1 (ko) * 1998-12-21 2004-09-13 주식회사 포스코 플라즈마를 이용한 대기오염물질 처리장치 및 그 방법
WO2001016031A3 (fr) * 1999-09-01 2001-09-20 Univ Abertay Dundee Procede
US6692632B1 (en) 1999-09-01 2004-02-17 University Of Abertay Dundee Method of producing hydroxyl radicals for chemical reactions
WO2004041725A3 (fr) * 2002-11-05 2004-08-26 Aquapure Technologies Ltd Procede et systeme de purification et de desinfection d'eau
US6802981B2 (en) 2002-11-05 2004-10-12 Aquapure Technologies Ltd. Method for purification and disinfection of water
WO2016103246A1 (fr) * 2014-12-23 2016-06-30 Oxypro Ltd. Procédé et dispositif de génération de peroxyde d'hydrogène
US9610559B2 (en) 2014-12-23 2017-04-04 Oxypro, Ltd Method and generator for generation of hydrogen peroxide
US10138562B2 (en) 2016-05-18 2018-11-27 Yefim Riskin Method for conversion of water into hydrogen peroxide and converter
WO2019082174A1 (fr) * 2017-10-23 2019-05-02 Oxypro Ltd. Procédé et dispositif de conversion d'eau en peroxyde d'hydrogène
RU2773011C1 (ru) * 2020-07-17 2022-05-30 Михаил Иванович Будник Устройство получения экологически чистого раствора пероксида водорода для стимуляции роста и развития растений

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AU5663196A (en) 1996-10-30

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