CA2547183A1

CA2547183A1 - Portable ozone generator for purifying water and use thereof

Info

Publication number: CA2547183A1
Application number: CA 2547183
Authority: CA
Inventors: Amir Salama; Marianne Salama
Original assignee: Ozomax Inc
Current assignee: Individual
Priority date: 2006-05-17
Filing date: 2006-05-17
Publication date: 2007-11-17
Also published as: BRPI0712093A2; EP2035337A4; CA2638633C; MX2008014549A; EP2035337A1; JP2009537290A; CN101448744A; WO2007131324A1; CA2638633A1; AP2008004710A0; US8440080B2; US20090114605A1; EP2035337B1; IL195350A0

Abstract

The present invention relates to a portable device for generating ozone in-situ in water in order to remove therefrom a large variety of pollutants, especially organic pollutants, in addition to bacteria and viruses, and thus make the water drinkable.
The device contains electrodes, and the current generated between them leads to the creation of hydrogen, oxygen, ozone and other oxidants. The electrodes used have rough surfaces; and the outer electrode contains series of holes with rough edges. The roughness of the surfaces of the electrodes and the roughness of the edges of the holes lead to a coalescence of tiny hydrogen bubbles into larger hydrogen bubbles; and the presence of the holes allow hydrogen bubbles to escape from inside the reactor. The hydrogen can be removed by absorption in a conductive material and regenerated for reuse. The production of ozone is thus maximized leading to high quality water purification.

Description

PORTABLE OZONE GENERATOR FOR PURIFYING WATER AND USE
THEREOF
Field of the invention The present invention relates to a portable device for generating ozone in-situ in water in order to remove therefrom a large variety of pollutants, especially organic pollutants, in addition to bacteria and viruses, and thus make the water drinkable.
In other words, the present invention relates to a water purifier which can work with a low voltage power supply and thus be easily portable. Furthermore, the purifier can be manufactured with a size adapted to its purpose, that is, the same principles of design may be applied to large water treatment applications. For example, the purifier can be as small as a pen and be directly plunged into a glass r 1... T4. 'f' .~I..r~ .~rl.~r~~-rl 4- l~- fiv-~-1 .~4 .~r~~i Lir~rl - ~ +nr~
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several devices may be installed in one or a series of large tanks to purify water.
Description of the prior art In order to carry out purification of water without the use of biocides such as chlorine and other chemicals, it is well known in the art to use ozone (03) as a disinfectant. Ozone is usually prepared outside the medium (water) and then injected inside the water by means of injectors or bubbling in a contact column.
Such makes the process bulky and costly as it involves the use of several devices.
Production of ozone (03) by electrolysis is a well known process since the 19tn century. Salt bridges with membranes were used to separate the ozone, oxygen and mixed oxidants produced around the anode from the hydrogen produced at the cathode. Platinum (Pt) wires were used as the anode and as the cathode.
The idea of membrane separation was also described and improved upon by the present inventor in US Patent No. 6,180,014, wherein relatively higher voltages were used to get sufficient ozone production than the new inventive device described hereafter.

Water purification systems are generally large devises, uneasy to carry and travel with. It would therefore be a significant advance in the art of water purification system to provide a portable water purification system, working with a iow voltage power supply by keeping the same purification efficiency and usable for purifying the water of a glass within a few second of time or fixing it at a tap anywhere you travel (hotel room).

Summary of the invention The object of the present invention is based on the discovery that the size of the hydrogen bubbles produced during the electrolysis strongly influences the final a r.iLt Ci C vw r,i.~ic.~.. ~ Tihil~'r.iyyr~ia~ c r nr~ Fhuic vuuv~ {~~ ~hhIc slne+, u ic =I~+i+ hiiyi ~c~inhr\1u ~c cr i~o }{.~~ ,~umiivr~-ui ~t ~r~} v~~i c.v~ icv~.~nr~r, i iou~ c i+ vc, the better and faster is the purification.

It is therefore a first object of the present invention to provide a device for purifying water by producing ozone in situ, which device comprises:

a) a housing for electrical connexion;

b) a reactor extending from the housing for insertion into the water to be purified, the reactor comprising:
i. an inner electrode having a rod shape, said inner electrode extending from the housing in the water; and ii. an outer electrode having a tubular shape, said outer electrode surrounding the inner electrode and extending also from the housing in the water;
the inner and the outer electrodes being separated by a gap;

and c) a power supply operatively connected to the inner and outer electrodes for generating between them a difference of potential creating a current, leading to the creation of hydrogen gas (H2) as bubbles, oxygen gas (02), ozone gas (03) and other oxidants, the hydrogen bubbles having a specific size.

The device according to the invention is characterized in that:
- the inner electrode has an outer rough surface in contact with the water, - the outer electrode has an inner rough surface and an outer rough surface both in contact with the water; and - the outer electrode contains a series of holes, said holes having rough edges;
whereby, in use, aL . ..,..... t =4.., .-L........ ~ =L... ,,...4 .....J... .J 44 - ll iC. 1 VUIJ.I 11 IGJJ VI lI IG JUI IQIiGJ VI LI IG GIGIU VUGJ QI 1U tl Ir.
roughness of the edges of the holes lead to a coalescence of tiny hydrogen bubbles into larger hydrogen bubbles;
- the presence of the holes allow hydrogen bubbles to escape from inside the reactor; and - the gap between the electrodes is optimized as function of said difference of potential, to maximise the specific size of the hydrogen bubbles.

Another object of the present invention is the use of the device defined above for purifying water.

The present invention has the advantage to reduce the voltage of the current required to produce sufficient amounts of ozone and mixed oxidants in electrolytic cell, by creating larger hydrogen bubbles and thus greatly reducing the reactivity surface between the hydrogen bubbles and the oxidants.

The present invention will be better understood upon reading the following non-restrictive description of a preferred embodiment thereof, made with reference to the accompanying drawings.

Brief description of the drawings FIGURE 1 is a schematic view of a water purification device according to the invention, plunged in a glass of water.

FIGURES 2a to 2c are longitudinal cross-sectional schematic views of the reactor shown in FIGURE 1, illustrating three different preferred embodiments of the invention.

FIGURE 3 is a longitudinal cross-sectional view of the purifying device plunged in a glass of water according to a first preferred embodiment of the invention.
FIGURE 4 is a longitudinal cross-sectional view of the purifying device plunged in a glass of water according to a second preferred embodiment of the invention.

FIGURE 5 is a longitudinal cross-sectional view of the reactor of a device plunged in a glass of water according to a third preferred embodiment of the invention.
FIGURE 6 is longitudinal cross-sectional schematic views of a reactor according to different preferred embodiments of the invention wherein the reactor is made of multiple cathodes and anodes.

FIGURES 7a to 7f are longitudinal cross-sectional views of the purification device shown in FIGURE 1, adapted to be fixed to a tap under different configurations relative to different preferred embodiments of the invention.

FIGURE 8 is a graphic representing the solubility of different gases in water for two different temperatures (20 C and 30 C).

Detailed description of the invention As aforesaid, the present invention relates to a device for purifying water by producing ozone in situ, such a device being preferably handy and transportable.
As illustrated on FIGURES 1, 3 to 5, the device (1) preferably comprises a housing containing electrical connexions (5), a reactor (7) extending from the housing in the water (9) and a power supply (not illustrated).

According to the preferred embodiment illustrated on FIGURES 1, 3 and 4, the reactor (7) comprises an inner anode (11) having a rod shape and extending from the housing (3) in the water (9). The anode is surrounded by a cathode (13) having --a..L...i...- stL.la.+....~.1c, eJLLGI lull R~. .a.....J7..... r.....,... i i vi i i a6lc u... L.......:... i ivuan iy _ = ii t ,uLiC _ wa'LC_r w i~") "di I
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the inner electrode (not visible on FIGURE 1). The inner anode (11) and the outer cathode (13) are separated by a tiny gap (15) better visible on FIGURE 2.

The power supply mentioned above is operatively connected to the anode and the cathode for generating between them a difference of potential creating a current. It is well known in the art that the eiectrolysis of water leads to the creation of hydrogen gas (H2), oxygen gas (02), ozone gas (03) and other oxidants inside the reactor, in the gap.
It has to be understood that all conductive surfaces can be made of rods, tubes with holes, perforated metal, wire mesh or wires which can be plated with Pt group metals, precious or semi-precious metals to create rough surfaces, semi-rough, smooth surfaces in case of H2 absorbing elements, or alloys. The choice depends on the operating parameters such as applied voltages, the gap between the anode and cathode, stirring speed and pressure.

As shown on the graphic represented on FIGURE 8, H2 is poorly soluble in water for a temperature ranging between 20 C and 30 C. Thus, H2 gas forms in water bubbles with specific sizes.

As better illustrated on FIGURE 2, the present invention resides in the fact that the surface of the inner anode (11), and the surfaces of the tubular shaped outer electrode (13) have been made rough. Although not illustrated, the same principles of design may be adapted to plate-type electrodes facing each other to produce ozone and mixed oxidants in situ.
Furthermore, the outer cathode has series of holes (17) with edges which have been also made rough (See FIGURE 1, inlet).

It has to be understood that the roughness of the surfaces of the electrodes and the roughness of the edges of the holes lead to a coalescence of tiny hydrogen lhhl~e in~~ I~rnrr hirlr~nr+n hh4+lr,n Cr+L+i+rrr~rr' 44.r' r i.i 44...
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allows hydrogen to escape from the reactor and thus reduces the possibility of contact between H2 and the oxidants (02, 03,...). The production of 03 will thus be enhanced. Finally, the tiny gap between the electrodes is optimized as function of said difference of potential and current, to maximise the size of the hydrogen bubbles.

The present invention first and foremost teaches us that in order to reduce the voltage required to produce sufficient amounts of ozone and mixed oxidants in electrolytic cell, hydrogen should be removed by one or a combination of the following methods.

1) As aforesaid, the hydrogen formed as the cathode can be removed by creating a cathode having surfaces which are rough inside and outside, and having holes with rough edges to promote the coalescence of tiny hydrogen bubbles into larger hydrogen bubbles (See FIGURES 1 and 2). These larger hydrogen bubbles (19) have a much smaller surface area thousand of times smaller than tiny hydrogen bubbles. These larger hydrogen bubbles have orders of magnitude less reactivity with the ozone and mixed oxidants produced at the anode, even if intermixing occurs. In other words, these large bubbles will produce less soluble hydrogen gas (Hz) in the water, hence less parasite reaction with 02, 03 and other mixed oxidants like peroxides, hydroxyl radicals, etc. Several experiments conducted in the inventor's laboratory have shown that high ozone concentrations of ozone can be achieved based on this principles reaching in some cases 1 ppm after 1 minute in 1 L of water using a 24 VDC voltage.
Rough surfaces may be produced mechanically, by chemical etching, by rough plating, by dendrite plating or a combination of these processes.

2) Hydrogen can be also removed by using a membrane at the inner, outer or both electrodes made of carbon fibres, textile carbon fibres, felt activated carbon, wire IIICJII or aly IIeUIa YYllllll IJ GIClLI1lQlly IVIdIAILIVG QIIU l..rCaLC Q
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fibres or porous media. These membranes will promote the formation of larger hydrogen bubbles and yield the benefits described above in part (1).
Alternative materials include organo-metallic compound such as epoxy filled copper, gold, palladium, nickel or metal powders coated with platinum, gold, palladium or other separate or in combination. Also conductive polymers like aniline type polymers 3) The hydrogen formed at the cathode can also be removed by using a coating on the cathode capable of absorbing hydrogen such as:
- metals or alloys from subgroups III, IV, V, VIII of the periodic table of elements selected from, but not limited to palladium, palladium alloys, magnesium alloys, and titanium alloys;
- special activated carbons or - other electrically conductive or H2 absorbing materials known in the art.

In this case, regeneration of the cathode may be required from time to time and may be accomplished by heating the cathode by flame or by an electrical resistance embedded or surrounding the cathode (See FIGURE 1, tab. B).
Reversing the polarity on the electrodes will also yield the desired regeneration effect.

4) As illustrated on FIGURE 6, the hydrogen can further be removed by using a second cathode (23) at the outside of the inner cathode to attract the hydrogen produced further away from the anode where the ozone and mixed oxidants are produced.

5) Finally, the hydrogen can be removed by reducing the gap between the anode and cathode, allowing less hydrogen to dissolve due to high H2 water saturation in the small gap between the cathode and the anode and will make H2 gas to escape without reacting with mixed dissolved oxidants. The gap is optimized as function of voltage, currei-it and iuw ihiougii peripiierai holes of 'the cathode to maximize dissolved 02, 03 and mix oxidants content in the water. It is well known that H2 is much less soluble in water than 02, 03 or mixed oxidants (See FIGURE 8).

As aforesaid, creating a small gap between the anode and cathode allows for more efficient electrolytic production of ozone and mixed oxidants at lower voltages and energy consumption.

Holes in cathode allow hydrogen to escape from reaction chamber thereby reducing its scavenging effect on the ozone and mixed oxidants produced may range from a few millimetres to a few centimetres in diameter depending on total length of the unit.

As illustrated on FIGURES 7a to 7f, a second cathode may be used to further attract the hydrogen from the ozone and mixed oxidants produced (23).

The device according to the invention, also named ozone pen or OZOPEN (trade name registration pending), may be powered by a DC power supply, batteries, solar power, small turbine, heated thermopile, activated by air or water flow, or other.
Both anode and cathode may be made of rods, rough surfaces, stars, meshes, plates or other shapes in any combination.

As illustrated on FIGURE 2b, the inner anode (11) can present micro-roughness (24) on its surface.

As illustrated on FIGURE 3, the purifier can preferably have an anode (11) of pure or plated platinum (Pt), palladium (Pd), or gold (Au) with smooth or rough plating, or dendritic plating. The anode can be in the form of a rod, a wire, a mesh or other form.

As illustrated on FIGURES 4 and 5, the device according to the present invention can preferably house a UV lamp (25) producing light with a wavelength from about 150 to about 300 nm, in order to aid in the production of ozone or hydroxyl radicals.

As illustrated on FIGURES 2c and 4, the reactor (7) preferably comprises a UV
lamp (25) surrounded by a transparent quartz or glass vessel (27) such as a tube, itself surrounded by a perforated tubular shaped anode (11). The anode surrounding the UV lamp is made of perforated precious metal such as Pt, Pd or Au. The anode can also be a perforated non-precious metal anode plated with Pt, Pd, Au or dendritic plating of precious metal. The anode can be in the form of a rod, a wire, a mesh or other form.

UV light may also be introduced into the Ozone Pen by including within its design green to deep UV LEDs (light emitting diodes) as the technology becomes available.

5 As iilustrated on FIGURE 5, the purifier can also preferably have external UV lights or UV LED (25) installed in the electrical housing. The UV light is thus introduced into the reactor via connected fibre optics or UV transparent glass (or quartz) rods (or tubes) (29), which can be suri-ounded by UV absorbing material (31) such as Lexan. The perforated anode (33) surrounded the inner cathode (35). The 10 perforated anode can be made of perforated precious metal such as Pt, Pd or Au.
The anode can also be a perforated non-precious metal anode plated with Pt, Pd, Au or dendritic plating of precious metal. The cathode can be made of Ni, Au, Pt, Pd or other smooth or rough plating. The cathode can be in the form of a rod, a wire, a mesh or other. The hydrogen (19) being produced at the inner cathode, water has to be manually or mechanically stirred (illustrated with big arrows on r1/1l 1Plrf1% n.. _~' .. a :....:...... :a L__ a L_ .-d__a_..J aL_a aL_ ._~..
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agitate the purifier into the glass of water to enhance the purification process.

The purifier according to the present invention can be a few centimetres to several meters long depending on the volume of water to be treated.

Accordinq to another embodiment of the present invention which is not illustrated on the FIGURES, the anode can be connected to a piezoelectric crystal actuated at a sufficient frequency to create pressure shock waves thereby enhancing the solubility of oxygen, ozone and mixed oxidants in water.

The device according to the present invention can also be installed in a way to increase the pressure thereby enhancing the solubility of oxygen, ozone and mixed oxidants in water. Large hydrogen bubbles will be reduced in size due to the higher pressure but will remain large enough to reduce the solubility of hydrogen at high pressure.

All of the above may be installed in a reverse fashion where the anode is found outside and the cathode is found at the center of the device (See FIGURE 5).

UV lights may be channelled to the outer diameter by optical devices, wave guides, fibre optics or UV emitting LEDs.

Another preferred embodiment of the present invention would consist of several layers of anodes and cathodes to increase the total surface area and thus maximizing ozone and mixed oxidant production (See FIGURE 6).

Finally, as illustrated on FIGURES 7a to 7f, the device (1) for purifying water according to the present invention can be easily installed directly at the end of a tap or faucet (39) or via a water inlet (50), in order to purify the water going out from it. The device having a small size, it can be easily transported in a baggage and instaiied anywhere needed, for exampie on ine tap of a notei room ii ine user believes that the water may contain batteries and germs. The same principles of design may be applied to the purification of water coming from artesian wells public fountains such as found in rural Africa.
As illustrated in FIGURES 7a to 7f, the purifier is preferably fitted to a faucet (39).
The electrical housina (3) is connected to the power supply (41) and to the reactor (7). A heating element (43) can be installed at the top of the reactor (7). A
tube (45) is fixed at the bottom of the reactor bringing the purified water outside the purifier (via E, F or K) or at the top of the reactor (via G, H or J). The entire device can be surrounded by a second full pipe cathode (23) in order to enhance the elimination of H2. As illustrated, hydrogen bubbles (D) travel from the inner cathode (13) to the outer cathode (23), leading to a diminution of H2 concentration inside the reactor (7) where the ozone is produced. The exit tube (45) can be curved as illustrated on FIGURE 7a (via F), or straight as illustrated on FIGURE 7b (via E).

Although the present invention has been explained hereinabove by way of a preferred embodiment thereof, it should be pointed out that any modifications to this preferred embodiment within the scope of the appended claims is not deemed to alter or change the nature and scope of the present invention.

Claims

1. A device for purifying water by producing ozone in situ, which device comprises:

a) a housing for electrical connexion;

b) a reactor extending from the housing for insertion into the water to be purified, the reactor comprising:
i. an inner electrode having a rod shape, said inner electrode extending from the housing into the water; and ii. an outer electrode having a tubular shape, said outer electrode surrounding the inner electrode and extending also from the housing into the water;
the inner and the outer electrodes being separated by a gap;
and c) a power supply operatively connected to the inner and outer electrodes for generating between them a difference of potential creating a current, leading to the creation of hydrogen gas (H2) as bubbles, oxygen gas (O2), ozone gas (O3) and other oxidants, said hydrogen bubbles having a specific size;
said device being characterized in that:
- the inner electrode has an outer rough surface in contact with the water, - the outer electrode has an inner rough surface and an outer rough surface both in contact with the water; and - the outer electrode containing series of holes, said holes having rough edges;
whereby, in use, - the roughness of the surfaces of the electrodes and the roughness of the edges of the holes lead to a coalescence of tiny hydrogen bubbles into larger hydrogen bubbles;
- the presence of the holes allow hydrogen bubbles to escape from inside the reactor; and - the gap between the electrodes is optimized as function of said difference of potential to maximise the specific size of the hydrogen bubbles.

2. The device according to claim 1, wherein the inner electrode is an anode and the outer electrode is a cathode.

3. The device according to claim 1, wherein the inner electrode is a cathode and the outer electrode is an anode.

4. Use of the device as defined in any one of claims 1 to 3, for purifying water.