Electrode, apparatus and method for electrolytic treatment of liquid, system for regenerating soil in situ and unit for performing reduction-oxidation reactions

FIELD: electrodes made of low electric conductivity material, electric connection with such electrode, use of such electrodes at treating liquids for removing contamination matters and for regenerating contaminated soil in situ.

SUBSTANCE: electrode includes elongated, mainly hollow body made of porous material characterized by comparatively low electric conductivity, connector in the form of elongated electrically conducting member connected to power source. Connector passes along inner cavity of electrode body and it has contact with surface of inner wall of body in large number of places mutually spaced along length of body for distributing electric current supplied from power source practically uniformly along electrode.

EFFECT: enhanced efficiency of electrolytic treatment of liquid contaminated with sewage waste, infection and radioactive matters at minimum voltage along electrode length.

12 cl, 3 dwg

The present invention relates to electrode made of a material with low electrical conductivity. Typically, these electrodes have the shape of an elongated hollow body. Preferably the case of this electrode is made of deteriorations oxide of titanium or similar material, and in this case, it is likely that the most effective method of production casing is obtained porous.

For illustration it has been estimated that when using tubular casing length 500 mm, with an external diameter of 18 mm and a wall thickness of 3 mm made of a material with a volume resistivity of 30 IOM·cm, with electrical connection at one end, at an amperage of 2.83 A (necessary to obtain a current density of 100 a/m²at all points along the length of the electrode), between the ends of such electrode voltage drop occurs, constituting approximately 750 mV. In many applications in electrochemical plants as a result of this voltage drop at the electrode can receive the region where the potential is insufficient to perform the proposed functions. In the case of the electrolytic process operating with a low potential difference of the order of 1-5 In between the anode and cathode (the preferred situation, because it usually reduces the cost of electricity), cannot warranty the VAT, that the entire surface area of the electrode will be equally effectively used, or will work at all. This applies in particular to such electrolytic processes such as water treatment, in which it is preferable to use electrodes with high excess capacity gassing on their surface (such as made of deteriorations titanium dioxide, lead dioxide, tin dioxide with additives and so on). In these cases, the resulting current density may vary between the ends of such electrode is greater than 50%.

The present invention relates to a method for electrical connection with such electrode, which will solve this problem, in particular, with the case electrode made of a porous material.

Known electrode having an elongated, generally hollow body made of a porous material with a relatively low electrical conductivity, and means compounds containing an elongated element, which is connected to a power source, and means of connection is located inside the body (see patent US 4422917). However, in the known electrode is not provided uniform distribution of electric current from the source along the electrode, thus not all of the surface area of the electrode is effectively used.

Technical financial p is tat from the use of the proposed invention is the efficiency of the electrolytic processing liquid, contaminated waste, wastewater, infectious and radioactive substances, with a minimum voltage along the electrode length.

This technical result is achieved due to the fact that the means of connection is in contact with the surface of the inner wall of the housing in the many individual apart locations along the length of the hull, almost uniform distribution of electric current from the power source along the electrode.

Conductive element has an electrical conductivity of essentially higher (at least 2 orders of magnitude higher)than the body of the electrode. In one form the means of connection is a conductor, twisted in the form of an elongated spring, the form of which creates a mechanical contact turns of the spring with the surface of the inner wall of the hollow body at regular intervals. In another variant embodiment of the separate segments of the conductor is connected at locations longitudinally spaced from each other, and each of them is in contact with the inner wall of the housing.

The hollow body may be made of materials selected within a certain range. It is most preferable to produce the body of the electrode from deteriorations oxide of titanium in the form of TiO_xwhere x ranges from approximately 1.99 to approximately 1,7. This case is, in General, porous, as most cost-effective processes for the production of cylindrical or hollow body of such materials result in a porous structure. It can contain the catalytic elements. In a preferred variant embodiment, the housing electrode is made of deteriorations oxide of titanium, and the conductor electrode made of a valve metal, making turns durable electrical connection.

The housing preferably has at least 200 mm in length, and the present invention is directed to the use of such materials, volume resistivity higher than about 20 mω·see If the body material has a higher resistivity, the present invention is applicable in cases where the length of the body is at least 150 mm

The electrode in accordance with the present invention is used in many processes, when it is preferable to use a cylindrical geometry of the electrode, such as processing liquids for the removal of pollutants and remediation of contaminated soil on site. In the main event, water-polluting substances can be grouped into the following seven classes:

1. Sewage and other waste, depleted in oxygen.

2. Infectious substances is A.

3. Plant nutrients.

4. Exotic organic chemicals.

5. Inorganic minerals and chemical compounds.

6. Fat.

7. Radioactive substances.

Sewage and other waste, depleted oxygen, usually a carbonaceous organic material which can be oxidized biologically or chemically) to carbon dioxide and water. These wastes can be problematic. Infectious substances are usually present in wastewater municipalities, resorts, tanning and meat processing plants and ships. This type of contamination can lead to diseases of man and animals, including livestock.

Plant nutrients (e.g. nitrogen and phosphorus) can stimulate the growth of aquatic plants, which prevent the use of water, and subsequent decay which leads to the formation of unpleasant odors and increase the number of water pollution, depleted in oxygen.

Exotic organic chemicals include surfactants used in detergents, pesticides, various industrial products and the products of decomposition of other organic substances. Some of these chemicals are known as toxic to fish at very low concentrations. Many of these compounds may not be neposredno is but to decompose biologically.

Inorganic materials and chemical compounds, in General, are present in the water, municipal institutions and industrial wastewater and urban runoff. These pollutants are harmful to fish and other forms of aquatic life or result in their death, and can make the water unsuitable for drinking or industrial use. A vivid example is the presence in water of mercury. Another example is the contamination of the salt used to remove ice from roads in winter in the Northern, cold climate.

Deposits represent the soil particles and minerals washed from the land during storms and floods, with arable land, unprotected forest soil, trampled down by cattle pastures, quarries, roads and cleared urban soils. Sediments fill the gutters and tanks; increase erosion in hydraulic turbines and pump equipment, reduce the amount of sunlight available to aquatic plants, clog water filters; and cover sediments spawning fish, caviar and places of feeding, thus reducing the populations of fish and shellfish.

Radioactive substances usually fall into the aquatic environment of waste development of deposits of uranium and thorium, as well as waste their refining; from nuclear power plants and in industrial, medical, scientific usage the education of radioactive material.

In another aspect of the present invention is directed to a device for use in electrolytic processing liquid, comprising a chamber containing the processed fluid, the anode and cathode, at least one of which is an electrode, in accordance with the present description, and the source of electric current.

The present invention, obviously, is particularly effective for the treatment of water or aqueous medium. In this case, electric current is passed between anode and cathode through a small gap, through which the water passes. Due to the structure of the electrode, in accordance with the present invention, it is possible to ensure that a predefined minimum voltage, for example, 3 will be present along the entire length of the electrode.

Electrodes made from deteriorations oxide of titanium, have a high excess capacity of the gas, i.e. the voltage required to obtain appreciable current due to the low catalytic activity of the surface, to split water into hydrogen and hydroxyl radicals. This level exceeds 1, if only the surface is catalyzed, so that the effective driving force for the current is mostly about 2 In (if the total voltage is 3 V, as described above) near to the connector and 1.25 In the other the second end of the voltage drop along the electrode, made without the use of the present invention, in the conditions described above.

In another aspect the present invention relates to a method of electrolytic processing liquid using the described device, including the supply of current from the power source to the electrode with low conductivity while providing a current density of more than 10 A/m²for the outer surface of the anode, due to what can be achieved by changing the voltage between any two points of the electrode is less than 200 mV.

For a better understanding of the present invention it will be described below as an example with reference to the accompanying drawings, on which:

Figure 1 depicts a schematic of an electrolytic cell for water treatment;

Figure 2 depicts an enlarged view in partial section of one of the variants of the embodiment schematically depicted in figure 1,

Figure 3 depicts another variant embodiment of the invention.

The water treatment system contains the cell where the treated water is fed into the annular space 2 between the two electrodes with an elongated tubular housing, with a small annular gap between them. The length of each electrode is typically 500 mm and they are connected to the corresponding pole of the source 4 DC voltage so that one electrode, not only the et a cathode 5 and the other end (in the drawing, the inner electrode) represents the anode 6. The internal electrode typically has an outside diameter of 18 mm, and the annular gap is typically 2 mm When the current passes through the electrodes, is an electrolytic reaction, such as water treatment to remove pollutants. The water flows in the annular gap between the electrodes. Typically, the electrical connection is led to one end of the internal electrode, and the electrodes serves the current order of 2.83 A. If the internal electrode is made of a tube of deteriorations oxide of titanium with a wall thickness of 3 mm and a specific volume resistance of 30 mω·see, without the use of the present invention, the voltage drop is approximately 750 mV along the length of the inner electrode so that the potential of the cell at one end will be approximately 3 V, and the other of 2.25 Century

In accordance with the present invention, the anode 6 in figure 1 includes an elongated tube 10, made of deteriorations titanium oxide, by forming by extrusion or by the use of such processes. The tube is approximately 500 mm, an inner diameter of 12 mm and an external diameter of 18 mm, a wall thickness of approximately 3 mm.

In accordance with one alternative embodiment of the present invention and as shown in figure 2, the supply line current is the length of the spring from about Aoki of titanium, which runs along the inner channel of the tube. One end of the connection means 11 made in the form of wire, is connected to the power source 4, the other end may be closed by a cap. The coils of the spring are in mechanical contact with the inner wall of the pipe separated from other places in L, so the power supply is distributed largely uniformly along the length of the tube. As a result, the voltage of the cell is essentially the same along the entire length of the cell and, consequently, the cell along the entire length will effectively perform its electrochemical function, such as the destruction of microorganisms, oxidation and/or restoration of' pollutants.

The cathode may have the same shape as the anode, or may be of a standard design.

In the variant embodiment shown in figure 3, the coils of the spring is replaced by a sequence of the individual connectors in the means of connection 12, located at some distance from each other along the length of the tube.

The present invention is not limited presents a variant of the embodiment. The water treatment device can contain a set of cells and include other types of processing. The electrode need not have a round cross-section. Although the present invention has been described in relation to water treatment, this electrode can be used in any si is wcii, when you want to use the elongated electrode. Such applications include the recovery of soil in place and electrochemical reactions of synthesis, for example, in a redox system.

1. The electrode containing an elongated, generally hollow body (5)made of a porous material with a relatively low electrical conductivity, and means (11, 12) compounds, which are an elongated conductive element, which is connected to the source (4) power tool connection is located inside the cavity of the housing (5), characterized in that the means of connection (11, 12) is in contact with the surface of the inner wall of the casing (5) in many separated apart locations along the length of the hull, almost uniform distribution of electric current from the power source along the electrode.

2. The electrode according to claim 1, in which the tool (11) connection is an elongated spring made of an elastic wire having a shape, which creates a mechanical contact turns of the spring with the inner surface of the housing wall (5) separated from each other along its length.

3. The electrode according to claim 1, in which the tool (12) of the compound contains a separate conductors that are in contact with the surface of the inner wall of the casing (5) is relevant to the respective places, separated from each other along its length.

4. The electrode according to claim 1, in which the conductive element has an electrical conductivity greater than at least two orders of magnitude conductivity of the body.

5. The electrode according to claim 1, in which case the electrode is made of deteriorations oxide of titanium in the form of TiO_xwhere x ranges from 1.99 to about 1.7.

6. The electrode according to claim 1, in which the length of the body is at least 200 mm

7. The electrode according to claim 1, in which the linking is made of a valve metal.

8. Device for electrolytic processing liquid, comprising a chamber containing the processed fluid, the anode and cathode, at least one of which is an electrode according to any one of claims 1 to 7.

9. The device according to claim 8, in which the fluid is a liquid aqueous waste or water, and the treatment consists in removing pollutants.

10. Method of electrolytic processing fluid using the device of claim 8 or 9, including the supply of current from the power source to the electrode with a density in excess of 10 a/m²in relation to the outer area of the anode, and the change in the voltage between any two points of the electrode is less than 200 mV.

11. System restore soil in place, including the electrode according to any one of claims 1 to 7.

12. The device for you is filling up redox reactions, including the electrode according to any one of claims 1 to 7.