Electrochemical devices for water treatment and disinfection

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STEL devices: history and new horizons

Name of STEL devices for synthesis of electrochemically activated antimicrobial and detergent solutions first appeared in 1989. This name is a combination of two words: STerility and Electrochemistry. This name united all types of electrochemical devices producing detergent disinfectant and sterilizing electrochemically activated solutions (ECA solutions) and containing electrochemical reactor consisting of flow-through electrochemical modular elements FEM-3. Due to particular qualities of design FEM-3 element has no alternative in the technology of ECA solutionsТ production. It is in this reactor only that it is possible to create conditions for simultaneous synthesis of chlorine-oxygen and hydroperoxide oxidants of the higher oxidation rates. In this reactor only it is possible to provide conditions for forming in double electric layer at the surface of anode of solid electrically structured ion-hydrated membranes, surrounding freshly formed oxidants and preventing them from the following rapid reciprocal (mutual) neutralization. In this reactor only it is possible to force hydrogen dissolved in catholyte to participate in the anodic reactions of synthesis of the oxidants.

The simplest technology of water treatment in flow through diaphragm reactors consists in simultaneous synthesis of approximately equal volumes of catholyte and anolyte Ц that is, of water or solution exposed to cathodic or anodic treatment, respectively. Perfection of the reactor in this technology manifests itself in the opportunity to obtain maximum possible values of anolyteТs oxidation-reduction potential (ORP) with its pH value being minimal, at that power inputs is minimal, output capacity maximum possible and initial solution or water mineralization minimal possible; as well as to obtain minimum possible ORP-values for catholyte with its pH value being maximal. That were these very conditions that were formerly considered to be the key conditions for УlivingФ and УdeadФ water generation, but in many cases they were achieved at the expense of increased water mineralization level and prolonged time of electrochemical water treatment. As a matter of fact, for obtaining electrochemically activated water Ц that may be called УlivingФ and УdeadФ Ц it is necessary to ensure that each micro-volume of water being treated gets in touch with the surface of the respective not dissolved in water electrode, provided that water temperature changes are minimal (1 Ц 2 degrees), water mineralization is minimal possible usually not exceeding the level of salts content in usual drinking water, and within minimal period of time usually countable in whole seconds or split seconds. It is obvious that the major part of apparatuses for УlivingФ and УdeadФ water generation manufactured in the early eighties, as well as of apparatuses of the similar destination being manufactured at present time, didnТt correspond and still do not correspond to these principals, as far as this area of electro-chemistry hasnТt ever been described in respective text-books and represents an independently developing scientific archipelago.

Generation of disinfectant solution Ц that is, of acidic anolyte in STEL devices doesnТt represent any difficulties as regards to technical aspects; however, it is not expedient for the reason of its high corrosiveness level and strong smell of chlorine. It is possible to avoid the strong chlorine smell only in case if usual drinking water with no salt additives is used as an initial solution; however, anolyte obtained of sweet water does not possess sufficiently effective antimicrobial properties so as to be used in PCDPI (LPU) (patient care and disease-prevention institution) as a disinfectant.

At the present time, STEL-AK devices for production of electrochemically activated anolyte and catholyte from sweet or distilled water having output capacity equal to 5 to 1000 litres\hour are manufactured in УNPO УEkranФ (Scientific-and-production association УEkranФ, JSC). Such electro-chemically activated solutions are applied in various technological processes implemented in agriculture, industry , including food processing, as well as in medicine for the purpose of oxidation-reduction potential regulation in the human beingsТ organisms.

ANOLYTE ЦAN

neutral anolyte

Employees of health care institutions performing practical tasks had a need for solution which would have a neutral pH value. For the first time such an anolyte was obtained in STEL-MT-1 device, the serial production of which was started in NPO УEkranФ in the year of 1990. This anolyte was given the name of a neutral anolyte, shortly УAnolyte ANФ, in contrast to formerly known acidic anolyte with the pH value being lower than 5, and at the same time the latter anolyte was given the name of УAnolyte AФ.

Anolyte AN is produced by way of anodic treatment only of the initial sodium chloride solution carried out in RPE-reactor represented by a single or by several FEM-elements. The pH value correction within the anodic treatment is performed by adjustment of the current share transferred by hydroxyl ions from cathodic chamber to anodic chamber, with sodium hydroxide concentration in cathodic chamber being maintained at increased level.

Anolyte AN proved to be a more strong antimicrobial solution than acidic anolyte. Moreover, in contrast to Anolyte A and due to particular qualities of the technology, it possesses detergent properties, as well. However, Anolyte A is characterized by high corrosiveness which is nearly the same as that of Anolyte A, but, in contrast to Anolyte A, it has less pungent smell of chlorine.

ANOLYTE ANK Ц neutral anolyte

obtained using catholyte

The further improvement of Anolyte AN properties has resulted in significant changes in the technology of electrochemical synthesis and permitted to create a neutral anolyte of the new type in the year of 1995; this anolyte was given the УAnolyte ANKФ reference name, which means Уneutral anolyte obtained using catholyteФ. Heavy metals ions removal from the initial sodium chloride solution, dissolved hydrogen properties utilization in oxidants mixture, as well as the technology of correction of the pH value of acidic anolyte solution are considered to be the most important aspects of the Anolyte ANK production technology.

As multiple experimental researches and wide experience of many years' practical application have shown, Anolyte ANK proved to be the solution which was the best to correspond with the needs of medicine: it possesses wide and universal spectrum of action, it is not toxic, it doesnТt create toxic background after desiccation, it doesnТt permit microorganisms to acquire resistance, and it has lower corroding ability than Anolyte AN.

Different hydraulic schemes can be applied for Anolyte ANK production. The most simple among them was used in all of the STEL devices that were manufactured before the year of 2006. In accordance with this scheme, the main point of Anolyte ANK synthesis consists in the whole initial solution volume supply to cathodic chamber of RPE-reactor consisting of FEM-3 elements, where catholyte, during the flowing process, is enriched with metals cations (mainly with sodium cations) coming from anodic chamber, and where heavy metals ions transform into insoluble hydroxides as a result of the medium pH value increase, as well. After that, hydrogen bubbles with the particles of insoluble hydroxides stuck to them and a certain quantity of catholyte are eliminated from the aggregate solution volume available in flotation reactor. Catholyte purified in such a manner is supplied to anodic chamber of the same reactor. As a rule, the pH value of Anolyte ANK to be selected shall lie within the limits of 6,5 to 7,5 and is adjusted with the help of catholyte volume discharged into drainage from flotation reactor.

However, this scheme, as well as Anolyte ANK generated with its help, is not free from disadvantages. When anolyte is produced in accordance with this scheme, salt conversion factor doesnТt exceed 13%, on the average, the latter fact results in necessity to retain the sodium chloride concentration in the initial solution at the level of not less than 5 grams/litre, in case the concentration of oxidants synthesized in Anolyte ANK lies within the limits of 500 Ц 600 milligrams/litre. When smooth shining surfaces are processed such an anolyte leaves the salt traces after its desiccation, with the latter fact calling forth the necessity of rinsing. Sporicidal activity retention cycle of Anolyte ANK doesnТt exceed 5 days, the latter feature being conditioned on incomplete heavy metals ions elimination from the initial solution. This scheme doesnТt permit to create technical electrochemical systems destined for long-term commercial operation (with the exception of medicine), as far as it is not able to provide favourable conditions for long-term service of FEM-elements anodic coating, in principle.

Within the period covering the years of 2000-2001 both the advantages and the accumulated problems of the technology and technique of Anolyte ANK production and practical application were revealed and studied.

The main advantages of Anolyte ANK are as follows:

• Anolyte ANK proved to be the most powerful and the most universal solution among all of the well-known liquid antimicrobial agents, with its toxicity being the lowest and with absolute environmental safety provided.
• Many yearsТ experience of Anolyte ANK practical application in PCDPI has proved that there are no microorganismsТ strains resistant to Anolyte ANK originating at all.
• STEL devices containing electrochemical reactors consisting of FEM-3 elements for Anolyte ANK production managed to provide thousands of PCDPI with inexpensive high-performance antimicrobial solutions that were harmless for patients, personnel and for surrounding environment, as well.
• By this time, Anolyte ANK obtained in STEL devices manufactured by УNPO УEkranФ, has been recognised as a therapeutic agent (anti-infective agent) for skin coverlets, mucous membranes and suppurating wounds disinfection, and for the other purposes, as well. There has been the respective pharmacopoeia certificate obtained.
  

There should be the following facts revealed within the period covering the years of 2000 Ц 2001 referred to disadvantages and problems of the technology and technique of electrochemically activated Anolyte ANK production and practical application in PCDPI.

Anolyte ANK possesses corrosiveness and is not recommended for cleansing of instruments manufactured of alloys which do not possess corrosion-resistance properties.

The effectiveness of objects disinfection with Anolyte ANK considerably decreases in the albuminous contaminating agents presence.

After its desiccation Anolyte ANK leaves the salt traces on smooth shining surfaces of objects.

The companies which which illegally manufacture and distribute STEL devices and are also involved in counterfeit FEM-elements manufacturing have caused ideological harm to original electrochemical activation technology and actual damage to customers.

Within the years of 2001 Ц 2005 the main Anolyte ANK disadvantages were successfully surmounted through the efforts of the group of specialists representing Electrochemical Medical Equipment Department of УNPO УEkranФ, JSC, УVitold Bakhir Electrochemical Systems and Technologies InstituteФ, American company УElectrochemical Technologies, Ltd.Ф: c.t.s (candidate of technical science) S.A. Panicheva, c.m.n (candidate of medical science) V.I. Prilutsky, c.t.s. (candidate of technical science) N.Yu. Shomovskaya.

1. STEL-ANK device is now developed. STEL-ANK ensures Anolyte ANK production according to the new technological scheme. Anolyte ANK obtained in STEL-ANK is characterised by low mineralization level (that is, total content of dissolved inorganic electrolytes), at that the concentration of metastable mixture of chlorine-oxygen and hydroperoxide oxidants is increased. Particularly, while the mineralization level of Anolyte ANK produced in STEL-10H-120-120-01 makes 2 to 5 grams/litre, provided that the oxidants concentration is equal to 200 to 500 mg/litre, the mineralization level of Anolyte ANK produced in STEL-ANK makes 0,5 to 2,0 grams/litre, with the same change of oxidants concentration provided. Low level of Anolyte ANK mineralization is the reason for its decreased corrosiveness rate and for simultaneously provided advanced antimicrobial properties, these characteristics being conditioned on more intensive osmotic transfer of active components to the micro-organismsТ internal environment. Furthermore, Anolyte ANK generated in STEL-ANK is characterised by longer antimicrobial activity retention cycle (up to 7 days), the latter fact being connected with advanced quality of the initial solution purification from heavy metals ions achieved within the process of Anolyte ANK synthesis in STEL-ANK.
2. Developed now is the technology of all-purpose (disinfection, pre-sterilization cleansing and sterilization) electrochemically activated solution generation Ц that is anolyte ALOKS. This solution is manufactured by means of ethyl alcohol infusing in the amount of 1 volume percent into Anolyte ANK produced in STEL-ANK devices only and having oxidants concentration equal to 500 mg/litre. Active components of anolyte ALOKS represent the mixture of metastable inorganic (chlorine-oxygen and hydroperoxide) and organic (peroxy-compounds) oxidants. Moreover, the major part of metastable organic oxidants is represented by per-acetic acid which is generated by means of progressive alcohol oxidation with inorganic oxidants of Anolyte ANK. Within 3 minutes after alcohol is infused and mixed with Anolyte ANK volume anolyte ALOKS is ready for application and will retain its functional properties within 6 hours. After 6 hours anolyte ALOKS is not recommended for application; and after 24 hours expire the active components of anolyte ALOKS almost completely neutralize each other. Anolyte ALOKS antimicrobial activity which has been proved by a number of authoritative foreign scientific research centres exceeds the analogous properties of Anolyte ANK by 1000 Ц 10 000 times, with the latter fact permitting to reduce the time of treatment of various items\medical-purpose products by this solution to 1 Ц 3 minutes. Anolyte ALOKS doesnТt provoke metals corrosion in case the immersion method is applied and it demonstrates high performance under the high organic load conditions.
3. Now developed are the technology and technical facilities for all-purpose (disinfection, pre-sterilization cleansing, steriliazation) electrochemically activated solution Ц Anolyte PEROX Ц generation. Anolyte PEROX is produced in STEL-PEROX devices by way of its electrochemical synthesis of sodium carbonate aqueous solution. The active components of Anolyte PEROX are sodium peroxy-carbonates, per-carbonic acid and hydroperoxide electron-acceptor compounds, their state being metastable Ц oxidants. The Anolyte PEROX mineralization level lies within the limits of 0,5 to 1,0 g/l; the oxidants content measured with the help of iodometric titration method in the active chlorine compounds equivalent makes 40 to 50 mg/l; the hydrogen value stays within the bounds of 6 to 7. This solution is characterised by minimal toxicity with no corrosiveness feature detected at all and is recommended for application not only as an agent for disinfection, pre-sterilisation cleansing and sterilisation of medical-purpose products but also as sterile water possessing antimicrobial properties which can retain for 20 days. With the abovementioned functions provided, Anolyte PEROX could be used for the medical-purpose products rinsing during the technological procedures of their preparation for application.
   
   Furthermore, during the Anolyte PEROX synthesis there is catholyte PEROX simultaneously synthesised in STEL-PEROX device; catholyte PEROX can be used as a washing solution, and as a medium for insecticides solutions preparation, as well. The level of catholyte PEROX mineralization doesnТt exceed 1 g/l, even if the pH value exceeds 10 and the oxidation-reduction potential is lower than minus 500 mV. Sodium hydroxide, hydrogen peroxide and other hydroperoxide electron-donor compounds, their state being metastable, Ц with all of them being oxidants Ц are the active components of catholyte PEROX. Catholyte PEROX application as a medium for insecticide preparations dissolution permits to improve functional properties of insecticides solutions, with the active components concentration being simultaneously reduced by 50 Ц 70 % owing to intensification of the processes of acting substances transfer through the insectsТ external integuments.
4. New technical systems are now developed. The reactors consisting of FEM-3 elements used in these systems can operate for no less than 50 000 hours without anodic coatings replacement and stopping for electrode chambers cleaning only. These new technical systems for Anolyte ANK generation , in which the salt conversion level mounts to 45%, have retained the УSTELФ name as the basic name; this was done so as not to violate the succession scheme ensuring that the electrochemical medical technique is perceived in accordance with its destination; however, depending on the type of hydraulic scheme of anolyte ANK generation various prefixes may be added, such as УSUPERФ (SUPERSTEL), as УANKФ (for example, STEL-ANK), УPEROXФ (for example, STEL-PEROX), УECOФ (ECOSTEL) or УECO-SФ (STEL-20-80-ECO-S)

The table given below represents the characteristics of new electrochemically activated solutions compared with that of existing chemical reagents solutions and of Anolyte ANK produced in STEL-10N-120-01 device.

Comparative characteristics of chemically stable and electrochemically activated disinfectant solutions.

Examination of infringing products (STEL devices, counterfeited electrochemical reactors manufactured by such Anglo-American company as УSTERILOXФ that presently changed itТs name for УPuricoreФ, or Russian company УEmeraldФ (NPP УIzumrudФ) located in Saint-Petersburg, for instance) which appear in the Russian market and abroad has shown that neither of the counterfeited electrochemical reactors permit to ensure that chlorine-oxygen and hydroperoxide compounds are generated in the Anolyte ANK synthesis scheme in proportions necessary for imparting of the required antimicrobial activity parameters to Anolyte ANK and does not permit to provide the conditions ensuring long-term simultaneous presence of chlorine-oxygen and hydroperoxide compounds in Anolyte ANK, as well. As a rule, the counterfeit STEL devices are equipped with either unoriginal reactors or with reactors consisting of standard FEM-3 elements manufactured by their only legal manufacturer all over the world Ц the Russian company УLaboratory of ElectrotechnologyФ (УLETФ, LLC), Ц with their quantity still being much less than the quantity required for achieving of the device output capacity stated in the respective documentation.

There are multiple violations of Anolyte ANK production equipment, of its generation technology and of its practical application methods committed by different companies which are not the authorised representatives of the authors. In order to give the STEL devices consumers Ц that is, the responsible employees of PCDPI, Ц an opportunity not to expose to risk the health of those people who have entrusted themselves to them as their patients there has been developed a system of the AUTHORТS INFORMATION provision to interested persons and organisations (www.vbinstitute.org), the abovementioned authorТs information covers all problems of electrochemical technique and technology. This system has been created on the basis of information database provided by the group of enterprises considered to be the leaders in the sphere of electrochemical systems and technologies of electrochemically activated solutions production and application and includes databases of the group of enterprises authorised by the authors - owners of the main patents issued in the described area; the latter fact permits to provide the customers with reliable information and high-quality products on their demands.

For more information please see:

• Infringements and infringers of intellectual property rights;
• About "inventors" and "historians";
• Intellectual property in the field of electrochemical activation engineering and technology, and protection of consumers' rights.