RU2351546C2 - Method for reduction of oxidation-reduction potential of water - Google Patents

Abstract

FIELD: sewage treatment facilities.

SUBSTANCE: invention is related to the field of physical-chemical methods for water treatment. Method for reduction of oxidation-reduction potential of water includes water passage through electrode chamber that contains anodes and cathodes connected to the source of DC voltage, and does not have separating semi-permeable membranes or diaphragms. Process is carried out for 10-600 s at intensity of electric field in interelectrode space of 1.5-24 V/cm.

EFFECT: reduction of water chemical composition changes and power inputs in lowering of oxidation-reduction potential of water, increased rate of water processing and provision of secondary water treatment from foreign admixtures.

3 cl, 2 dwg, 4 tbl, 6 ex

Description

The invention relates to the field of technology related to the implementation of physico-chemical methods of water treatment in order to improve its consumer characteristics.

Known methods of water treatment (the so-called "revitalization" of water) that improve its perception by living organisms and lead to various biological effects, which, ultimately, are expressed in the ability of treated water to maintain a better quality of life (see, for example, K.K. Kalninsh, L.P. Pavlova, Water - the spring of life. Monograph / IVS RAS, SPSUTD, - St. Petersburg. - 2005. - 293 s).

Among these methods are known such as treating water with constant and alternating magnetic fields, flint, shungite and corals, as well as passing water through the cathode and anode chambers of membrane electrolyzers (electrochemical activation of water). The most studied is the positive effect on the human or animal organism of “revitalized” (or simply “living”) water, in those cases when it is accompanied by a well-defined physicochemical effect, which consists in lowering the oxidation-reduction potential (ORP) of the treated water. This is due to the development of a theory that relates ORP to the intensity of bioenergetic processes in the body associated with the transfer of electrons along the so-called respiratory chain, as well as the negative effect of oxidative processes on organically tissues.

As is known, the redox potential (ORP) is a measure of the chemical activity of elements or their compounds in reversible chemical processes associated with a change in the charge of ions in solutions. In other words, the redox potential, also called the redox potential (Eh), characterizes the degree of electron activity in redox reactions in equilibrium under standard conditions (temperature, concentration of substances, atmospheric pressure), i.e. in reactions associated with the attachment or transfer of electrons. The value of the redox potential for each redox reaction is expressed in millivolts and can have both positive and negative values.

The metrological basis for the quantitative determination of the ORP is the connection of the electrode potentials of inert electrodes with the activities of both the oxidized and reduced forms of the substance.

In natural water, there are always substances that are oxidizing and reducing agents, and Eh for natural and tap water, as a rule, are in the range from -400 to +700 mV, which is determined by the totality of the oxidation and reduction processes occurring in it. Oxidizing agents include, for example, such components of water as oxygen, nitrate ions, a number of elements in the highest form of their valency (Fe ³⁺ , Mo ⁶⁺ , As ^5- , V ⁵⁺ , U ⁶⁺ , Sr ⁴⁺ , Cu ²⁺ , Pb ²⁺ ). The reducing agents include hydrogen sulfide, ammonia, metals of low valency (Fe ²⁺ , Mn ²⁺ , Mo ⁴⁺ , V ⁴⁺ , U ⁴⁺ ), humic acids and many other organic compounds. The ratio of these or other compounds largely determines the oxidizing or reducing properties of water. At the same time, the structural characteristics of water as a liquid crystal system also influence these properties.

The AFP indicator is increasingly used in medicine, which, relying on knowledge of this value, uses water for therapeutic, sanitary, hygienic and veterinary purposes. Reducing the ORP of water, according to doctors and biologists, leads to an improvement in its bioenergy, metabolic and immunostimulating properties. It also provides favorable conditions for the development of microorganisms and plants. With regular use of water with reduced AFP, in particular, the state of internal organs, skin, mucous membranes and human hair improves. The development of normal microflora of the human body is stimulated, and as a result, the negative consequences of dysbiosis are reduced. It is generally accepted that a shift in donor – acceptor equilibrium in body fluids in favor of acceptors, leading to a deficiency of reactive electrons, is a key link in an extensive class of pathological processes that occur in living organisms.

Analogs of the claimed invention are electrolytic methods implemented using membrane electrolyzers manufactured by industry and widely discussed in the scientific literature (see, for example, V.M.Bakhir. Modern technical electrochemical systems for disinfection, purification and activation of water. M., VNIIMT, 1999). It is these methods that have so far made it possible to achieve the most reliable and significant reduction in AFP. In the most general terms, the activation processes in membrane electrolyzers are as follows. Water alkalization occurs in the cathode chambers of electrolytic cells due to the discharge on the cathode cathodes, i.e., water enrichment with OH ^- hydroxyl ions, while reverse processes occur in the anode chambers - acidification of water due to its enrichment with protons (or hydroxonium ions Н ₃ О ⁺ ).

The closest analogue of the claimed invention is a method implemented in the utility model RU 24214, 07.27.2002.

The main disadvantage of the prototype is due to the use of the known method of the so-called electrochemical activation of water, which, by changing the ORP, inevitably leads to a change in the chemical composition of water (i.e., it actually introduces foreign substances into the water that are formed on the electrodes, primarily hydrogen or hydroxyl ions The pH of such water upon activation changes by a few pH units.In fact, we are not talking about a decrease in the ORP due to the structural characteristics of the water itself, but rather about catholytes - solutions of electrolytes in the cathode space, which have an integrally lower ORP than the source water, which naturally imposes stringent requirements on the composition of the treated water and does not allow separate management of the ORP factors, on the one hand, and the chemical composition factors of catholyte, including pH number.

Other disadvantages of the prototype are related:

- with relatively high energy costs necessary to obtain stable effects of water activation (the required amounts of electricity, expressed in coulombs per liter, are of the order of hundreds of C / l), structural complexity and low productivity of electrolyzers, which, in particular, still cannot be manufactured devices with a capacity of more than 1 m ³ / h (more often we are talking about tens of m ³ activated water per hour);

- with an increased residence time of each portion of treated water in the cells of the electrolytic cells, that is, with a low linear flow rate;

- with the fact that they do not provide associated water purification from microparticles, including microbial cells, as well as from anions and weakly ionized, but prone to aggregation components;

- with the fact that the prototype method provides the electrochemical activation of water only when it is supplied in the discrete mode characteristic of devices called dispensers (or coolers);

- with the fact that the electrochemical activation provided by the utility model of the prototype does not guarantee the acquisition by water of the properties of “living” water, since the decrease in the ORP of the latter is accompanied by giving it the properties of bactericidal (ie biotoxicity).

The objective of the invention is to create a more efficient method, devoid of the above disadvantages, suitable:

- to solve a wide variety of biomedical problems when water with antioxidant properties but normal pH values is required,

- ensuring water supply with reduced ORP in any modes: both continuous and discrete,

- to solve the problems of purification and neutralization of aquatic environments in different areas of the economy while giving it the properties of "living" water.

The formulated problem is solved using the method consisting in the fact that when using a number of known techniques characterizing the prototype, namely, passing water through an electrode chamber containing anodes and cathodes connected to a constant voltage source, unlike the prototype, the chamber does not contain semi-permeable membranes or diaphragms, as a result of which the treated water is not divided into anode and cathode flows. In this case, protons and hydroxyl groups formed as a result of electrolysis of water have the ability to instantly recombine, while maintaining the pH of the water at the initial level. As a result, there is mainly only a modification of the liquid crystal structure formed by polar H ₂ O molecules, which are also prone to the formation of hydrogen bonds, directly under the influence of the electric field strength factor.

The present invention provides an effective solution to the most complex of the tasks. If not only a decrease in the ORP is required, but also water purification from foreign inclusions, both effects can be achieved simultaneously by passing water through the considered electrode chamber with an interelectrode space filled with polarizable granular materials.

Features and practical applicability of the proposed method is illustrated by the following examples.

Example 1. For the treatment of water, a cylindrical electrode chamber of the KASKAD AVE-7/40 water electric air conditioner (TU 4859-013-54176675-2003), commercially available by ElectroEcoTechnology, was used. The working chamber of the apparatus has plane-parallel electrodes with a height of 200 mm and an interelectrode distance of 50 mm. The volume of the chamber is 40 liters. There are no interelectrode partitions in the chamber.

Water for treatment was taken from the city water supply in St. Petersburg. Water was treated in the duct with linear flow rates indicated in Table 1. The voltage values at the electrodes and the current through the cell are also given in Table 1.

Table 1 Linear flow rate, cm / min 0 (control) 6 24 62 205 310 Electrode voltage, V 0 12 12 12 12 12 Electricity fields, V / cm 0 3 3 3 3 3 Current, A 0 0.91 0.90 0.89 0.89 0.89 The value of the ORP of water, mV 410 -10 0 5 182 398 pH of water, units 6.8 6.7 6.8 6.8 6.8 6.8

From table 1 it follows that at all flow rates taken: from 6 cm / min (200 l / h) up to values of the order of 310 cm / min (10 m ³ / h), the effect of decreasing ORP at a constant pH takes place, which corresponds to quantities of electricity passed through water, respectively, from 13 to 0.26 C / l. Only in the case of the highest flow rate at a taken voltage of 12 V, the effect becomes insignificant. The data presented indicate a predominantly electrophysical rather than electrochemical mechanism of the effect.

Example 2. For the treatment of tap water, an electrode chamber was used, as in Example 1. The anodes and cathodes were connected to a constant voltage source with an adjustable output in the range from 1.0 to 96 V. The linear velocity of the water passed through the cell was maintained at 6 cm / min

table 2 Electrode voltage, V 0 6 12 24 36 48 72 96 Electricity fields, V / cm 0 1.5 3.0 6.0 9.0 12 eighteen 24 Current, A 0 0.48 0.90 1.75 2.61 3.43 5.15 6.82 The value of the ORP of water, mV 380 10 -3 -69 -150 -180 -230 -240 pH of water, units 6.8 6.8 6.8 6.8 6.8 6.7 6.7 6.6

From table 2 it is seen that with increasing voltage on the electrodes (electric field strength in the interelectrode space) and, accordingly, the magnitude of the electric current transmitted through water, the shift of the ORP towards negative values in the studied voltage range increases.

Example 3. For the treatment of water, a cylindrical electrode chamber of the KASKAD AVE-1.3 / 5 electric water conditioner, commercially available from ElEcoTech, was used. The camera has 350 mm coaxial electrodes. Diameters: anode - 80 mm, cathodes - 34 and 129 mm. There are no interelectrode partitions in the chamber. The volume of the camera is 5 liters. The anode, as well as the internal and external cathodes were connected to a constant voltage source of 12 or 24 V. The lower part of the interelectrode space (3 L), which can be filled with quartz sand, was empty in this experiment.

Water for treatment was taken from the city water supply in St. Petersburg. In order to identify the role of factors such as voltage and the amount of electricity passed through the water, the water was treated for different residence times of water in the working chamber at two different voltage values on the electrodes 12 and 48 V, as shown in Tables 3, 4.

Table 3 The voltage at the electrodes is 12 V, the current is 0.45 A. Processing time, s 0 (control) 10 60 120 300 600 The value of the ORP of water, mV 380 17 -eleven -19 -19 -eighteen pH of water, units 6.8 6.8 6.8 6.7 6.7 6.6 Table 4 The voltage at the electrodes is 48 V, the current is 1.77 A. Processing time, s 0 (control) 10 60 120 300 600 The value of the ORP of water, mV 380 -40 -92 -108 -120 -110 pH of water, units 6.8 6.8 6.8 6.7 6.6 6.5

From the above data it is seen that:

- increase in processing time, i.e. the amount of electricity passed through the water, starting from some values at a fixed voltage, slightly increases the effect of decreasing the ORP, even leading to a decrease in the effect at the end of the taken interval (due to the accumulation of electrolysis products in water);

the effect of transmitting a certain amount of electricity at a lower voltage on the electrodes (for example, at 12 V, see column 4 in table 3):

0.45 · 600 = 270 C,

{where I (current, A) · t (time, s) = Q (amount of transmitted electricity, C)}

- the effect of transmitting a certain amount of electricity at a lower voltage on the electrodes (for example, at 12 V, 0.45 A · 60 s · 10 = 270 C), is less than when transmitting a smaller amount of electricity (1.77 A · 60 s = 106 , 2 C, see column 4 in Table 4), but at a higher voltage, for example 48 V. This indicates the predominance of field (i.e. physical) effects on water over electrochemical effects (consistent with the well-known Faraday law), which are used when implementing the prototype method.

Example 4. For the treatment of water, the electrode chamber of the KASKAD AVE-1.3 / 5 water electric air conditioner was used, as in Example 3. The lower part of the electrode chamber (3 L) was filled with quartz sand with a grain size of 0.3-0.6 mm

Water was passed through an electrode chamber from an underground well in the vicinity of the village of Toksovo (Lena oblast), containing an increased concentration of iron ions (about 15 mg / l).

The linear flow rate was maintained at 12 cm / min. The ORP value of the source water was (182 ± 5) mV, pH 7.1

After passing water through the electrode chamber, the ORP value decreased to (-50 ± 1) mV. At the same time, the concentration of iron ions decreased to values (0.2-0.3) mg / l, that is, along with the effect of reducing ORP to physiologically more favorable values, there was an effect of purifying water from iron ions and bringing this indicator in line with the current hygienic norms (SanPiN 2.1.4.1074-01. "Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems"). the pH of the water as a result of processing increased slightly by 0.1 units. - from 7.1 to 7.2.

Example 5. For the treatment of water, the electrode chamber of the KASKAD AVE-1.3 / 5 water electroconditioner was used, as in examples 3, 4. The interelectrode space was filled with spherical granules based on a styrene-divinylbenzene copolymer with a diameter of 0.3-1.0 mm

Water was passed through an electrode chamber from a river in the area of the Sevastyanovo village (Lena oblast), which, due to the content of a large number of suspended particles, had a turbidity index that significantly exceeded that required by SanPiN 2.1.4.1074-01, namely, 23.7 mg / l, instead of the required 1.5 mg / l.

The linear flow rate was maintained at 12 cm / min, the voltage at the electrodes was 24 V. The ORP value of the source water was (396 ± 10) mV.

After passing water through the electrode chamber, the ORP value decreased to (-10 ± 1) mV. In this case, the turbidity index decreased to values (0.8-0.9) mg / l, that is, along with the effect of decreasing the ORP, there was the effect of purifying the water from suspended particles and bringing this indicator in accordance with applicable hygiene standards (SanPiN 2.1.4.1074 -01). The pH of the water as a result of processing was maintained at 6.9.

Example 6. For the treatment of water, the electrode chamber of the KASKAD AVE-1.3 / 5 water electric air conditioner was used, as in Examples 3-4.

Water from a well having a conductivity of 240 μS · cm ^{-1 was} passed through an electrode chamber, which corresponded to a total water salinity of about 120 mg / L.

The linear flow rate was maintained at 12 cm / min, the voltage at the electrodes was 24 V. The ORP value of the source water was (366 ± 10) mV. After passing through the electrode chamber, the ORP was (280 ± 10) mV.

The source water was deionized by distillation. At the same time, the electrical conductivity of water decreased to 2-3 μS · cm ^-1 , and the ORP value after electric treatment decreased to -90 mV, that is, the effect of decreasing the ORP very significantly increased the pH of the water as a result of processing fell insignificantly, only 0.1 units. - from 7.2 to 7.1.

Claims (3)

1. A method of reducing the redox potential of water, including passing water through an electrode chamber containing anodes and cathodes connected to a constant voltage source, characterized in that the water passing through a chamber that does not have dividing semipermeable membranes or diaphragms, and the process is carried out at electric field intensities in the interelectrode space in the range of 1.5-24 V / cm, with a residence time of water in the interelectrode space from 10 to 600 s. 2. The method according to claim 1, characterized in that the water is passed through an electrode chamber filled with polarizable granular materials. 3. The method according to claims 1 and 2, characterized in that the water is subjected to deionization before treatment, and then passed through an electrode chamber.