RU2075994C1 - Method and apparatus (versions) for liquids purification - Google Patents

Abstract

FIELD: methods and apparatuses for liquids purification. SUBSTANCE: method provides for liquid passing through layer of sorbent placed in field of electric current at speed of no more than 50 h^-1 with following sorbent regeneration in electric current field. In the case electric field is created by electrodes made of materials, that during contacting each other create chemical source of electric current. Apparatuses have body, in which sorbent and electrodes are located. In the case in one of apparatuses electrodes are made of materials, that during contacting each other create chemical source of electric current and are located in sorbent, and in another apparatus particles of sorbent are made of material, that during contacting material of electrodes creates chemical source of electric current, and in third apparatus electrodes are made of sorbent particles of materials, that during contacting each other create chemical source of electric current. EFFECT: improved process of liquids purification and designs of apparatuses. 8 cl, 3 dwg

Description

 The invention relates to physical chemistry, and in particular to methods and devices for cleaning liquids from foreign inclusions (microorganisms, suspended particles, colloids), and can be used for water treatment, wastewater and other liquids.

 The most widely used filtration methods, often using sorbent filtration materials, based on the passage of liquid through an apparatus containing a housing in which the filter element is located. As the latter, along with porous natural and synthetic materials, sand, anthracite, activated carbon, zeolites, etc. are used.

 The disadvantage of most of these water purification methods is the relatively low degree of water purification from microorganisms and colloids at relatively high filtration rates (more than 1 m / h).

 To increase the efficiency of filtration systems, it is proposed to use the polarization of filter nozzles using an electric field.

The prototype of the proposed group of inventions is a method of wastewater treatment (ed. St. USSR N 950681, class C 02 F 1/468, 08/15/82). consisting in the fact that water is passed through clay or silica gel, placed in an electric current field of 1-100 V / cm, and the water feed rate is (5-7) • 10 ^-4 m / s. Cleaning is carried out multistage on the same sorbent with increasing field strength from cycle to cycle by 5-25 V / cm.

 The device used, the electrolytic cell consists of a housing divided by membranes into three containers, one of which contains a sorbent, and two other electrodes connected to a current source. As electrodes, graphite or platinum plates are used.

 The regeneration of the sorbent is carried out after turning off the current by washing it with water.

 The disadvantage of this method and device was the low separation efficiency, low cleaning speeds, multi-stage, high energy costs.

 The objective of the invention is to reduce energy costs and increase the efficiency of liquid purification, simplifying process technology.

The problem was solved due to the fact that particles capable of polarizing in an electric current field were used as an sorbent, and electrodes consisting of substances capable of forming a chemical current source (galvanic couple) upon contact were used as a source of energy, regeneration processes were carried out without turning off the electric current current, and the fluid flow rate did not exceed 50 h ^-1 .

 An electric current arises between individual pairs of electrodes that are brought into contact as a result of the use of materials that are far enough apart from each other in the electric voltage series, for example, carbon-containing materials, platinum or silver (as the anode) and aluminum , zinc, stainless steel, titanium, zirconium (as a cathode). For non-aqueous liquid systems, sodium and lithium electrodes may be used. The difference in electrical potentials between the electrodes of the electrocolumn of the proposed purification device is formed due to the chemical energy of redox reactions that occur on the electrodes when they are closed by an external circuit. Oxidizers and reducing agents that donate or acquire electrons on the surface of dissimilar electrodes immersed in a solution, which is essentially any sample of water, are anions and cations (primarily hydroxyl ions and protons formed during spontaneous dissociation of water).

 The electric field strength was established based on the nature and degree of contamination of liquids, however, as shown by experimental data, reliable cleaning of various contaminants is achieved at a voltage of at least 1 V / cm.

 For effective cleaning, the process is carried out in a fluidized bed of the sorbent, to maintain which the particle size should not exceed half the distance between adjacent electrodes, which is usually 0.3-3.0 mm.

 Suspensions of particles from a material polarized in an electric field, for example, ferroceramics, silica sand, crushed zeolite or marble chips, ion exchange resins, magnetite, schungite, activated carbon, chitosan, etc., are used as sorbents.

 The regeneration of the sorbent is carried out by a fluid flow, the speed of which is at least 1.5 times higher than the fluid velocity in the cleaning mode, and it seems optimal to supply the regenerating liquid in the direction opposite to cleaning.

 The method of water purification is implemented in one of three versions of devices, common to which is the presence of a housing, in the inner tank of which there is a chemical source of electric field and dispersed material polarized in the field. In this case, the chemical source of the field can be formed due to the interaction of two electrodes that form a galvanic couple, one electrode that forms a galvanic couple from one of the parts of the sorbent placed in the same container with the sorbent; at least two components of the sorbent, which form a galvanic couple. A combination of these characteristics in one sorbent is also possible.

 The general diagram of the main embodiment of the device is shown in FIG. one.

 The device consists of a housing 1, equipped with input 2 and output 3 fittings having locking lattices 4 and 5, between which are installed positive 6 and negative 7 electrodes, closed to each other.

 The fittings can be additionally equipped with control devices (gate valves) 8.

 In the gaps between the electrodes, which are set equal to 0.3 3.0 mm, granules of a polarizable filler (packing) 9 are placed, for example, ferroceramic powder, quartz sand, crushed zeolite or marble chips, granules of a sorbent based on chitokhan or ion-exchange resins.

 In general, the set of elements 1 9 forms an electrocolumn, which can be mounted on a horizontal surface (table, floor) using a stand (base) or tripod, or mounted vertically on a wall.

 The device operates as follows.

 The liquid through the nozzle 2 with the speed set by the regulating device (valve) 8 enters the housing 1, passes through the sorbent 9, polarized by the field created by the electrodes 6 and 7, and the impurities are sorbed on the sorbent, after which the liquid leaves the housing through the nozzle 3.

 During regeneration, the flow of fluid through the pipe 2 stops. The washing liquid is supplied through the nozzle 3 with a speed exceeding the cleaning rate by at least 1.5 2 times (the speed is set by the valve 8 on the nozzle 3), and then passing through the sorbent 9, polarized by the field of the electric current created by the electrodes 6 and 7, the sorbed impurities are washed out and through pipe 2 goes into the drain. The cleaning time, as a rule, is 8 10 hours, the regeneration time of 0.5 to 15 minutes

 The service life of the device without changing the sorbent is at least 2 3 years.

 The differences of the proposed device from the prototype are the placement of the current source in one container with the sorbent, the nature of the material of the sorbent and electrodes, as well as the particle size of the sorbent.

 A diagram of a second embodiment of the device is shown in FIG. 2. As in the first embodiment, it consists of a housing 1, equipped with input 2 and output 3 fittings having locking lattices 4 and 5, between which an electrode 6 is installed in the internal capacity of the housing (can be made of the same material as the housing), forming a galvanic pair with a sorbent material 9 (chemical current source).

 Particles of sorbent 9 are placed in the interelectrode space, and the nozzles are equipped with valves (regenerating devices) 8.

 The operation of the device according to option 2 is fully equivalent to that of option 1.

 The device of embodiment 3 is shown in FIG. 3 and consists of a housing 1 with fittings 2 and 3, equipped with valves 8 and shut-off grids 4 and 5. A sorbent 9 is placed in the housing, the material of which is capable of forming a galvanic pair between the components of the materials that make up the sorbent.

 The operation of the device according to option 3 is similar to their work according to option 1.

 A feature of the proposed method and all variants of the device is that they provide the implementation of a highly efficient electrosorption principle of cleaning in the absence of energy consumption from an external electric current source (power supply unit), high quality cleaning is achieved while reducing energy consumption and improving safety by eliminating any possibility of operator damage electric shock.

 These method and device in the literature on water treatment are not described, which indicates the compliance of the claimed technical solutions with the criterion of significant novelty.

 The method and the device created for its implementation have shown high efficiency in treating water from sufficiently contaminated sources with great convenience and absolute electrical safety in operation.

 The practical effectiveness of the method and device is illustrated by examples.

 Example 1. Water taken from a fire reservoir near the Khimvolokno Research Institute was passed through a device consisting of 10 pairs of anodes and cathodes made of food-grade aluminum and carbon-filled polyethylene. All electrodes were short-circuited. The gaps between the electrodes, the dimensions of which were 600x150 mm, were 1.5 2.0 mm. The gaps between the electrodes were filled with a T-11,000 ferroceramic powder with a dielectric constant of 15,000. The sizes of the ferroceramic granules were in the range of 0.25 0.63 mm. The electric field strength in the interelectrode gaps was 7 9 V / cm. The water pumping rate was 2.5 and 7.0 l / h. The regeneration of the electrosorbent was carried out after 20 hours of operation of the device by pumping clean water in the opposite direction at a speed of 12 to 14 l / h for 5 minutes.

 Measurements of the potential difference between the external surfaces of the device and the Earth bus, made throughout the experiment, fractions of a value not exceeding 1 mV, which is many orders of magnitude lower than threshold values that pose a danger to human health.

Water analysis was performed by measuring the optical density (D) using an LOMO SF-26 spectrophotometer at a wavelength of 460 nm, as well as by seeding samples on nutrient media to determine the coli index (CI) and total microbial contamination (OMO). Sowing was carried out by placing 0.1 ml of liquid in Petri dishes with nutrient media (Endo, meat-peptone agar) and incubating them for 24 hours at 36-38 ^o C. The concentration of iron ions ([Fe]), which were removed from water in in the form of hydroxide microparticles, it was controlled by the atomic absorption method using a Perkin Elmer spectrometer.

 The cleaning results are shown in table. one.

 From the table. 1, it follows that the water that was initially unsuitable for drinking, seeded with microorganisms after this treatment began to meet the requirements for drinking water with the standard standards, being essentially sterile.

 Example 2. In the conditions of example 1 using quartz sand as a nozzle, water was pumped at a speed of 2 and 10 l / h. The data obtained using the above analytical methods and characterizing the degree of water purification, as well as the quality of nozzle regeneration are given in table. 2.

 The data table. 2 show that cleaning using the proposed method and device is also possible when using not only ferroceramics, but also quartz sand. In this case, although somewhat worse, the cleaning parameters are quite acceptable.

 Similar results were obtained when chitosan granules, marble chips, composite sorbents based on polystyrene beads coated with ferroceramic chips were loaded into the device.

 Example 3. In the conditions of example 1, a similar device was used for water purification (option 2), characterized in that it did not have a system of carbon fiber electrodes, and the functions of the latter were transferred to a dispersed filler, which used shungite granules of size 0.4 1.0 mm, the field strength was 1 2 V / cm.

 The obtained experimental data are given in table. 3.

 As follows from the above data, the proposed method and device for cleaning liquids are very effective, do not require additional energy, are technically simple and exclude any possibility of electric shock to the operator, therefore they are especially suitable for treating water in domestic as well as field and camp conditions.

 Example 4. In the conditions of example 3, a device was used, the casing of which was a cylindrical column with a diameter of 50 mm and a length of 450 mm, made of a piece of polyethylene pipe with inlet and outlet fittings at the ends protected by nylon nets. The column was filled with a mixture of schungite granules (as in Example 3) and aluminum shavings in approximately equal volume proportions.

 The results of the experiment are given in table. 4.

Claims (8)

1. A method for cleaning liquids, including passing them through a layer of sorbent placed in an electric current field created by electrodes, followed by regeneration of the sorbent, characterized in that the liquid is passed at a speed of not more than 50 h ^{- 1} , the sorbent particles are polarized by an electric current field, electrodes They are made of materials forming a chemical current source upon contact with each other, and the sorbent is regenerated in an electric current field.  2. The method according to claim 1, characterized in that the purification of liquids is carried out at an electric field strength of at least 1 V / cm.  3. The method according to PP. 1 and 2, characterized in that as the sorbent use particles whose size does not exceed half the distance between adjacent electrodes.  4. The method according to PP. 1 to 3, characterized in that the regeneration of the sorbent is carried out by a fluid flow at a speed not less than 1.5 times the flow rate of the cleaned liquid.  5. The method according to claims 1 to 4, characterized in that the regenerating liquid is supplied in the direction opposite to the flow of the liquid being cleaned.  6. A device for cleaning liquids, comprising a housing in which a sorbent and electrodes are placed that create an electric current field, characterized in that the electrodes are placed in a sorbent, wherein the electrodes are made of materials forming a chemical current source and particles the sorbent is made of a material polarized in an electric current field, and the particle size does not exceed half the distance between adjacent electrodes.  7. A device for cleaning liquids, comprising a housing in which a sorbent and electrodes are placed, characterized in that the electrodes are placed in a sorbent, wherein the sorbent particles are made of a material that forms a chemical current source upon contact with the electrode material.  8. A device for cleaning liquids, comprising a housing in which a sorbent and electrodes are placed, characterized in that the electrodes are made in the form of particles of a sorbent from materials forming a chemical current source upon contact with each other.

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