DE102006007931A1 - Preparing a disinfectant, useful e.g. to disinfect water such as rain water, comprises adding an electrolytic solution to water, and subjecting the diluted water/electrolytic solution to an electric current - Google Patents

Abstract

Preparation of a disinfectant by electro-chemical activation of water comprises adding an electrolytic solution to the water, and subjecting the diluted water/electrolytic solution to an electric current by applying a direct current to the electrodes. Preparation of a disinfectant by electro-chemical activation of water comprises adding an electrolytic solution, preferably sodium and/or potassium chloride solution to the water, and subjecting the diluted water/electrolytic solution to an electric current by applying a direct current to the electrodes in a first electrolysis reactor (6) having at least a cathode region with a cathode and at least an anode region with an anode, which is spatially separated from the cathode region, preferably by a diaphragm, to displace the diluted water/electrolytic solution into a metastable state, which is suitable for disinfection, where the pH of the diluted water/electrolytic solution in the anode region is adjusted to 2.5-3.5. An independent claim is included for the disinfectant in the form of an electro-chemically activated, anodic, diluted water/electrolyte solution, obtained by the above method.

Description

The The invention relates to a method for the disinfection of water, such as Drinking and service water, rainwater, industrial water. and the like, by electrochemical activation (ECA) by adding at least a partial flow of the water to be disinfected, an electrolyte solution, in particular a sodium chloride solution added and that with the electrolyte solution acted upon water in an electrolysis reactor with at least a cathode compartment with a cathode and at least one of the cathode space spatially, in particular by means of a diaphragm or a membrane, separate Anode space with an anode by applying a DC voltage the electrodes are supplied with an electric current to the water / electrolyte solution into a suitable for disinfection metastable state. The invention further relates to a process for the preparation of a disinfectant by electrochemical activation (ECA) of water by adding to the water an electrolyte solution, in particular a sodium chloride solution and that acted upon by the electrolyte solution Water in an electrolysis reactor with at least one cathode compartment with a cathode and with at least one of the cathode compartment spatially, in particular by means of a diaphragm or a membrane, separate Anode space with an anode by applying a DC voltage the electrodes are supplied with an electric current to the water / electrolyte solution into a suitable for disinfection metastable state. moreover the invention is based on a disinfectant prepared in this way and directed to its use.

The Method of electrochemical activation for the disinfection of Water is known. This is a dilute solution of an electrolyte, in particular a neutral salt, such as sodium chloride (NaCl) or saline, in an electrolysis reactor by applying a voltage to its Electrodes in a metastable state, which, depending on the nature of Water and the set process parameters over several Can last for hours. The electrolysis reactor has a cathode compartment with one or more cathodes and an anode compartment with one or more anodes, wherein the anode space and the cathode space by means of an electrically conductive - in particular one for Ion conductive - Diaphragm or by means of a membrane with the properties mentioned spatially from each other are separated to a mixture of located in both rooms Water / electrolyte solution to prevent. While in the electrolysis usually a substantially complete conversion of the sought educts, the electrolyte solution used is at the electrochemical activation only to a very small extent implemented the physical and chemical properties of the solution to change in an advantageous manner and in particular the redox potential of the staggered with the electrolyte th To increase water, whereby a disinfecting effect is obtained. Advantageous is in particular the good health and environmental compatibility on the occasion of electrochemical activation generated substances in their respective Concentrations, which according to the German Drinking Water Ordinance (TwVO) are also approved.

As with electrolysis, oxidation also occurs at the anode (ie at the positively charged electrode) during electrochemical activation, while at the cathode (ie at the negatively charged electrode) there is a reduction. When using a diluted neutral salt solution, such as a sodium chloride solution, primarily hydrogen is generated at the cathode according to the following reaction equation (1): 2H ₂ O + 2e ^- ---> H ₂ + 2OH ^- (1) which is discharged after outgassing from the solution, for example, from the cathode compartment of the reactor.

At the anode, in particular the chemical oxidants oxygen (O ₂ ) and chlorine (Cl ₂ ) are produced according to the following reaction equations (2) and (3), which are known to be effective with respect to a disinfection of water: 6H ₂ O ---> O ₂ + 4H ₃ O ⁺ + 4e ^- (2) 2Cl ^- ---> Cl ₂ + 2e ^- (3)

Chlorine in turn dissociates in water according to the following equilibrium reaction (4) in hypochlorite ion (OCl ^- ) and chloride ion (Cl ^- ), which in turn with a suitable cation, eg Na ⁺ from the electrolyte, or with a proton or a H ₃ O ⁺ -Ion to the corresponding (sodium salt or to the corresponding acid, ie to hypochlorous acid (HClO) and hydrogen chloride or dilute hydrochloric acid (HCl) can assemble: Cl ₂ + 3H ₂ O <===> 2H ₃ O ⁺ + OCl ^- + Cl ^- (4).

Further, from the aforementioned materials formed at the anode by secondary reactions, further substances can be produced, which are also known to be effective in terms of disinfection of water. These are in particular hydrogen peroxide (H ₂ O ₂ , reaction equation (5)), ozone (O ₃ , reaction equation (6)), chlorine dioxide (ClO ₂ , reaction equation (7)), Chlorate (ClO ₃ ^-, equation (8)), and various radicals (reaction equations (9) and (10)). 4H ₂ O ---> H ₂ O ₂ + 2H ₃ O ⁺ + 2e ^- (5) O ₂ + 3H ₂ O ---> O ₃ + 2H ₃ O ⁺ + 2e ^- (6) Cl ^- + 4OH ^- ---> ClO ₂ + 2H ₂ O + 5e ^- (7), 3OCl ^- ---> ClO ₃ ^- + 2Cl ^- (8) 5H ₂ O ---> HO ₂ ^. + 3H ₃ O ⁺ + 3e ^- (9), H ₂ O ₂ + H ₂ O ---> HO ₂ ^. + H ₃ O ⁺ + e ^- (10).

A disadvantage of the method of electrochemical activation is in particular the lack of quality control, since the required for a sufficient disinfection of the water, mostly empirically determined process parameters, such as amount of added electrolyte solution, adjusted electrode voltage or current and the like, not only by the electrolysis reactor used, as its reaction volume, its anode and cathode surface, the residence time of the water to be disinfected in the reactor, etc., but in particular also on the composition of the respective water to be disinfected, in particular its conductivity and its redox potential depend. Furthermore, it has been shown that the solutions prepared by means of electrochemical activation according to the prior art are usually - sometimes highly contaminated with undesirable products, often according to the above reaction equation (3) almost exclusively chlorine gas (Cl ₂ ) is produced, which causes a pungent odor of the electrochemically activated solution. Moreover, owing to the composition of the electrochemically activated solution which fluctuates greatly as a function of the abovementioned parameters, it is not possible to make reliable statements as to the durability or storability of the electrochemically activated solution, so that virtually only a production of the same takes place on site. In practice, therefore, the method has - mainly due to its poor handling and the insufficiently possible guarantee of adequate disinfection - on the market can not prevail.

Of the The invention is therefore based on the object, a process for the preparation of a disinfectant by electrochemical activation (ECA) of water or a method for disinfecting water by means of to develop such a disinfectant of the type mentioned in the beginning, that one essentially consistently high disinfecting effect of the disinfectant or the water to be disinfected is ensured which especially the Drinking Water Ordinance is sufficient. She is also on disinfectant produced by such a process and directed to its use.

In From a process engineering point of view, this object is achieved in a generic method for the disinfection of water by electrochemical activation (ECA) solved in that the pH of the Water / electrolyte solution in the anode compartment of the electrolytic reactor to a value between 2.5 and 3.5 is controlled. Furthermore, to solve this Task in a generic method for the preparation of a disinfectant by electrochemical Activation (ECA) of water according to the invention provided that the pH the water / electrolyte solution controlled in the anode chamber to a value between 2.5 and 3.5 is, wherein the disinfectant in the form of such electrochemical activated, anodic water / electrolyte solution is obtained. Regarding the disinfectant itself sees the invention for solving the their underlying problem by means of such a procedure prepared disinfectant.

Surprisingly, it has been found that when adjusting the pH of the water / electrolyte solution, ie the water to be disinfected with the admixed in this electrolyte, such as the sodium chloride solution, to a value between about 2.5 and about 3.5, preferably to a value between about 2.7 and about 3.3, in particular to a value between about 2.8 and about 3.2, for example to a value between about 2.9 and about 3.1, such as to a value of about 3.0, not only a virtually constant disinfecting effect for drinking and service water with virtually any composition, but also provides a sufficient depot effect, which makes no further disinfection steps more necessary and which persists especially in the case of shock loads. The inventive control of the pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor leads to a potential-controlled anodic oxidation (PAO), wherein a redox potential between about 1240 mV and about 1360 mV, preferably between about 1280 mV and about 1360 mV, in particular between about 1320 mV and about 1360 mV. Investigations have not only shown that the Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecium used as test germs at a dilution of the prepared in the manner according to the invention by electrochemical activation under potential-controlled anodic oxidation, anodic water / electrolyte solution of about 1: 400 within about 30 s by more than four orders of magnitude can be reduced, but that also older pipelines with an already optically visible infestation of a biorasen be virtually completely freed from the biorasen within two to four weeks. Consequently, a dilution of about 1: 400 already represents, for example, a highly efficient dilution suitable for disinfecting drinking and service water or swimming pool water. As will be explained in more detail below, it is of course also possible to use the anodic water produced by the process according to the invention. / Electrolytic solution - eg in concentrated form - for a variety of other applications. Furthermore, it is of course also possible in the case of disinfection of water, for example, even over a limited period, higher concentrations or lower dilutions of the anodic water / electrolyte solution to add the water to be disinfected, in the case of occurred in piping calamities for a to provide effective acute treatment. Such dilutions may then be, for example, between about 1: 100 to about 1: 200, the dilution being of course fundamentally dependent on the particular application.

Furthermore it was found that the setting the pH of the anodic water / electrolyte solution in the electrolysis reactor on the pH range according to the invention no permanent Lowering the pH of the water to be disinfected on this Value causes, due to the relatively acidic pH for many potential applications electrochemical activation, e.g. for drinking water, could be undesirable. This is on the one hand at the very low, for disinfection of Water required metered amount of disinfectant in the form of the electrochemically activated, anodic water / electrolyte solution (e.g. in a dilution from about 1: 300 to 1: 500), depending on the buffering capacity of the water even with very soft waters a pH reduction of at most about -0.2 causes. On the other hand, the pH rises again after some time, with it is suspected that this on the decay of the occasion of the electrochemical activation generated metastable substances, such as Ozone, various radicals, etc. (see also the above reaction equations), is due. Nevertheless, however - like already mentioned - the excellent Disinfection effect achieved.

Moreover, the formation of chlorine gas according to the above reaction equation (3) can be limited to a minimum, so that the disinfectant in the form of electrochemically activated, anodic water / electrolyte solution at best has a very weak chlorine odor, while the disinfected water, which this solution in has been added to the appropriate dilution, has no smell characteristic of chlorine at all. As a result of the potential-controlled anodic oxidation, hypochlorites, such as sodium hypochlorite (NaClO), metastable radical compounds and in smaller amounts of hydrogen chloride instead of chlorine gas (Cl ₂ ) are produced, ie the balance of the above reaction equation (4) is apparently shifted to the right by the process of the invention ,

Due to the spatial separation of the anode space, in which the disinfectant highly effective, electrochemically activated water / electrolytic solution is generated from the cathode space is a mixing of the products generated during the electrochemical activation in the anode compartment products with the products produced in the cathode compartment and thus the formation of to prevent disinfection of the water little (s) suitable substances. This can be done for example by a separation of the anode space from the cathode space of the electrolysis reactor by means of a diaphragm, a membrane or the like, which (s) is electrically conductive, but substantially liquid-tight. In this context, for example, a diaphragm / membrane of porous zirconia (ZrO ₂ ) has been found to be suitable.

With "control of pH to a value in the range of 2.5 to 3.5 "is meant for the purposes of the invention, that this from the cathode compartment through an electrically conductive (s) Diaphragm / membrane spatially Separate anode compartment of the electrolytic reactor emerging solution - or the electrochemically activated, anodic water / electrolyte solution -, having such a pH, i. the control of the pH happens such that this pH has been set at the end of the reactor. With "control" of the pH is both a suitable, more or less static default the process parameters and in particular a dynamic control the process parameters during the reactor operation addressed.

The pH of the water / electrolyte solution in the anode compartment can basically be controlled in various ways. While it is possible in principle for this purpose, in addition to the electrolyte to be disinfected water in each case a suitable amount of an acid such as a Mineralsäu or an organic acid, is provided in a preferred embodiment, that the pH on the range of values according to the invention is controlled without any additional - to add additional acid. As can be seen from the above reaction equations taking place at the anode, proton or H ₃ O ⁺ ions are often produced in the oxidation reactions taking place at the anode, which consequently reduce the pH. For this reason, it is possible to control the pH alone to adjust the occurring at the anode reactions within the range of the invention, wherein an increase in the conversion achieved at the anode during the electrochemical activation results in an increased generation of protons and consequently a lower pH. The conversion obtained on the occasion of the electrochemical activation can in turn be increased for a given reactor geometry by adjusting an increased current flow between the electrodes or by applying a higher voltage to the electrodes (which results in a higher electrical current flow between the electrodes), by increasing the residence time of the water / electrolyte solution in the reactor (or, if a continuous or semi-continuous process is provided - by slowing the volume flow of the solution through the reactor), and / or adding more electrolyte solution, eg more sodium chloride solution is, so an increased educt amount is used.

on the other hand it is because of this dependence the pH of the Water / electrolyte solution of the conversion of the electrolyte in the anode compartment of the reactor also possible, the To measure pH directly or indirectly to this way to obtain an actual value which - e.g. by means of conventional control equipment, such as by means of a PID controller - on the The target value according to the invention can be controlled can. According to one preferred embodiment The invention is therefore intended that the pH of the water / electrolyte solution directly measured by means of a pH meter. Alternatively or additionally be provided that the pH of the water / electrolyte solution indirectly over the flowing between the electrodes Current is measured (e.g. the voltage required to achieve such a current, which must be applied to the electrodes) and / or that the pH the water / electrolyte solution indirectly via the residence time in or - in the case a (semi) continuous process control - on the flow rate of the same is measured by the electrolysis reactor.

As already indicated, provides a preferred embodiment of the method according to the invention before that pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor by controlled addition the appropriate amount of electrolyte solution is controlled, i. it will more electrolyte solution, i.e. more educt, added when the pH must be lowered to in the range of the invention to be controlled while less electrolyte solution, i.e. less starting material is added when the pH is increased must, um in the range according to the invention to be controlled. The addition of the appropriate amount Electrolyte solution, e.g. Sodium chloride solution, can be done for example by means of a metering pump, wherein the This produced water / electrolyte solution before entering the Electrolysis reactor is preferably mixed as homogeneously as possible, around for a smooth operation of the electrolysis reactor. As a suitable mixing device In particular, a ball mixer has proven in which the water / electrolyte solution by a ballast is directed.

alternative or additionally can in a preferred embodiment be provided that the pH of the water / electrolyte solution in the anode space by controlling the current flowing between the electrodes is controlled by e.g. to the electrodes of the electrolysis reactor a suitable voltage is applied, which is one for achieving the pH range according to the invention required current flow ensures. Further, it is alternatively or additionally possible that the pH of the water / electrolyte solution by Anode space by controlling the residence time and / or the flow rate of the same in which or by the electrolysis reactor is controlled. In each Case can one or more parameters substantially at a constant value be kept or regulated.

In order to calibrate an electrolysis reactor with a given reactor geometry as a function of the water to be disinfected, ie to make an adjustment of the process parameters required for controlling the pH of the water / electrolyte solution to the value range according to the invention, provides an advantageous embodiment of the method that for controlling the pH of the water / electrolyte solution in the anode chamber of the electrolysis reactor to a pH of between 2.5 and 3.5, in particular between 2.7 and 3.3, at a predetermined desired current between the electrodes of the electrolysis reactor a is determined by the respective composition of the water to be disinfected dwell time (T _V ) and / or depending on the particular composition of the water flow rate (V ') of the water / electrolyte solution in or by the electrolysis reactor is determined. An advantageous embodiment of the method provides that the residence time (T _V ) and / or the volume flow (V ') in or through the electrolysis reactor as a function of the conductivity (κ) and / or the hardness (H) of Water is detected. Since, in particular, the conductivity of the water has a relatively great influence on the residence time of the solution in the reactor required for achieving the pH according to the invention or, in the case of a (semi) continuous process, on the corresponding volume flow through the reactor, it is up This way it is possible to first determine a residence time / volume flow which is appropriate for the water to be disinfected, wherein to determine this dependence, a suitable current is applied to the electrodes of the reactor, which, for example, can be determined empirically and preferably - as well as the amount of metered-in electrolyte solution - is kept constant. It can be provided that the residence time or the volume flow is determined instead of depending on the conductivity of the water to be disinfected depending on the representative of the electrical conductivity of the water hardness of the water, ie instead of the total concentration of ions contained in the water proportional conductivity of the water is only the hardness, ie its concentration of calcium and magnesium ions used.

A preferred embodiment provides in this context that the residence time (T _V ) and / or the volume flow (V ') in accordance with a straight-line equation of the form T V = k 1 · Κ + k 2 and or V '= k 3 · H + k 4 where k ₁ , k ₂ , k ₃ and k _{4 are} reactor specific constants. The above-mentioned straight-line equations can be determined, for example, in a simple manner by adding waters of different conductivity at a certain residence time in or with a specific volume flow through the reactor and under a certain - in particular constant - metered addition to electrolyte solution and at a certain - in particular constant - Current flow between the electrodes of the electrolysis reactor are electrochemically activated and while the pH is controlled to the value range according to the invention, after which the residence time or volume flows required for the different waters are applied depending on the electrical conductivity of the water and the reactor with a accordingly Volume flow (or residence time) is operated.

In a further preferred embodiment of the method according to the invention it is provided that for controlling the pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor to a pH between 2.5 and 3.5, in particular between 2.7 and 3.3 , for a given residence time (T _V ) of the water / electrolyte solution in the electrolysis reactor and / or for a given volume flow (V ') of the water / electrolyte solution through the electrolysis reactor, a static target flow dependent on the particular composition of the water to be disinfected ( I _{soll, stat} ) between the electrodes is determined. Also in this case, it is advantageous if the static nominal current (I _{soll, stat} ) is determined as a function of the conductivity (κ) and / or of the hardness (H) of the water. Moreover, in turn, it may preferably be provided that the static nominal current I _{soll, stat} according to a straight-line equation of the form I should, stat = K 1 · Κ + K 2 and or I should, stat = K 3 · H + K 4 where K ₁ , K ₂ , K ₃ and K _{4 are} reactor specific constants.

In order to provide a more or less static control of the anodic potential of the electrolysis reactor of the type mentioned above for a dynamic control depending on the possibly changing over time, actual parameters, provides a particularly preferred embodiment of the inventive method that for control the pH of the water / electrolyte solution in the anode chamber of the electrolysis reactor (6) to a pH of between 2.5 and 3.5, in particular between 2.7 and 3.3, at a predetermined static nominal current (I _{soll, Stat} ) between the electrodes of the electrolytic reactor _is determined by the respective residence time of the water / electrolyte solution in the electrolysis reactor and / or by the respective volume flow of the water / electrolyte solution by the electrolysis reactor dependent dynamic target current (I _{soll, dyn} ), so that the control of the reactor for the purpose of maintaining the pH of the el electrochemically activated, anodic water / electrolyte solution in the range of 3 in situ depending on the measured actual parameters, such as the residence time or the volume flow, can be done.

The dynamic setpoint current (I _{soll, dyn} ) is preferably also in accordance with a straight-line equation of the form I should, dyn = K 5 * T V + K 6 and or I should, dyn = K 7 · V '+ K 4 where K ₅ , K ₆ , K ₇ and K _{8 are} reactor specific constants.

To the electrodes of the electrolysis reactor is preferably in such a control, which includes both static, depending on the particular water used adjusting components and dynamic, dependent on the actual measured parameters control components Total nominal current (I _{soll, ges} ) is applied, which is formed from the sum of the static nominal current (I _{soll, stat} ) and the dynamic nominal current (I _{soll, dyn} ): I should, ges = I should, stat + I should, dyn

As already mentioned, is the amount of added electrolyte solution both in terms of default of the reactor as well as during the operation is kept substantially constant, the reactor e.g. always in its optimal operating condition with a specific one Volume flow of water (or with a certain residence time of the water in the reactor) and e.g. in case of disinfection of water with peak loads of great needs and rest periods low demand can be provided, the reactor on the one hand of Time to time shut down (e.g., during rest periods) and on the other hand a memory for to provide the produced electrochemically activated, anodic water / electrolyte solution, to bridge peak loads.

A particular advantage of the dynamic control component of the control according to the invention is that in the case when the measured residence time of the water / electrolytic solution and / or the measured volume flow of the same sinks in or through the electrolysis reactor, at such a measured drop of this residence time and / or this volume flow of the total current flowing between the electrodes (I _{soll, ges} ) can also be lowered for a short time due to the dynamic component (I _{soll, dyn} ). It has been found that, in particular in the case of continuous operation of the electrochemical activation gas bubbles can form, in particular from ausgasender to be disinfected water oxygen and chlorine gas, whereby the conversion achieved in the electrochemical activation is impaired and consequently the pH increases and further wherein a reduction of the volume flow through the reactor is detectable. In order to counteract this, in particular a short-term reduction of the current flowing between the electrodes of the electrolysis reactor has proved to be advantageous, which is possible due to the dynamic portion of the desired current. Such a measure of the dynamic control or regulation can also be appropriate independently of the inventively provided static control of the pH of the water / electrolyte solution depending on the conductivity or the hardness of the water to a formation of gas bubbles in the Electrolysis reactor, which is apparently due to a kind of labile balance to eliminate and return to a suitable for proper disinfection of the water operation of the electrochemical activation.

As already mentioned, may preferably be provided that the electrolyte solution in Form one - in particular Substantially saturated - added sodium chloride solution. However, other electrolyte solutions are conceivable, with - also due their extremely high solubility in water - in particular Neutral salts with an alkali metal cation, preferably from the Sodium (Na) and potassium (K), and with a halogen anion, preferably from the group fluorine (F), chlorine (Cl), bromine (Br) and Iodine (I) proved to be expedient to have.

As As already indicated, it can not be just in terms of manufacturing the disinfectant of the invention itself, but also in the case of disinfecting water from Be an advantage, exclusively the generated in the anode compartment, electrochemically activated water / electrolyte solution for disinfection of water and less suitable for disinfection, in the cathode compartment generated solution to reject.

Further it may be particularly beneficial in the disinfection of water, if a partial flow diverted from the water to be disinfected, the Partial flow electrochemically activated and at least (or exclusively) the in the anode compartment electrochemically activated partial flow to be disinfected Water is added as a disinfectant, said disinfectant - as already mentioned - depending on Use case e.g. at a dilution of about 1: 200 to about 1: 500 is added to the water to be disinfected again.

Finally is the inventive method especially suitable for continuous or semi-continuous implementation, a partial flow of the water to be disinfected or the Production of the disinfectant in the form of the invention electrochemically activated, anodic water / electrolyte solution (semi) continuous passed through the electrolysis reactor.

The invention further relates to a disinfectant in the form of an electrochemically activated, anodic water / electrolyte solution prepared in the manner according to the invention. The solution prepared according to the method according to the invention can be used as a disinfectant, for example everywhere where a perfect disinfection of water, especially in compliance with the Drinking Water Ordinance is required, such as for disinfection of municipal water supply or water supply to hospitals, schools, nursing homes, Commercial enterprises, hotels or other catering establishments and sports clubs (eg for dosing into the water of the sanitary facilities), railway stations, airports, canteen kitchens, for disinfecting swimming pool water or Re for desalination plants, such as seawater desalination plants on ships or inland, to prevent the carryover of germs in the water of textile washing machines, for fast discoloration of dyeing effluents, for virtually any Industrial (ab) water, such as for admixing with cooling water (for example for lathes, milling, drilling, cutting or other machine tools), for air conditioning and humidification systems, for osmosis plants, as an additive to the water for mixing in concrete and cement, as an additive to the water in the manufacture of electronic components and circuits, as an addition to the water of cut flowers, for metering into the drinking and waste water of livestock farms and slaughterhouses or for disinfecting devices used in this context, such as incubators, milking machines and the like , etc. In all Cases for acute disinfection or during normal operation, a reliable disinfection is achieved and the unwanted formation of algae and / or sludge is prevented. The disinfectant may be used either in substantially pure form or, in particular in water treatment, in the form of a dilution of up to about 1: 500, preferably up to about 1: 400, proportions of a diluent, such as water, in which case the water treatment, for example, a dilution in the range of about 1: 400 has proven in many cases to be useful.

The Disinfectants in the form of electrochemically activated according to the invention, anodic water / electrolyte solution can over it out - too e.g. in pure form or in particular in the form of a respectively suitable Dilution - for disinfection of foods such as cereals or flour, spices, fruits, vegetables, ice cream and as a coolant serving ice, e.g. in the storage of meat, fish and seafood during transport and sales, animal products and the like, wherein a perfect kill of germs, such as putrefactive bacteria etc., and thus with a very good health compatibility one longer Shelf Life is achieved.

Of Another is a use of a disinfectant according to the invention for Disinfecting seeds, e.g. as silage and Preservative in the storage of seeds and cereals can be used in silos.

One Another preferred application of such a disinfectant consists in the disinfection of packaging containers and packaging, in particular for hygienic Products, such as food, pharmaceuticals, sterile items (such as syringes, Surgical instruments, etc.) and the like.

moreover may be a use of such a disinfectant for reaction media to carry out of solvent and emulsion polymerizations favorable be, with the use of emulsifiers required for this purpose is reduced and the polymerization rate surprisingly increased can be, as it is in an experiment on the occasion of Production of Divinylstyrolkautschuk has shown.

Further There is another preferred field of application of such Disinfectant as an additive for in particular water-soluble paints, varnishes and pigments which can be given a biocidal effect, as well as an additive for Cold and Lubricant, e.g. For industrial cooling circuits or for technical Lubricant based on water, oil or grease.

Finally, can such a disinfectant also as an additive for propellant and fuels, such as fuel oil, Gasoline, kerosene and the like.

In all cases can the disinfectant in the form of in accordance with the invention electrochemically activated anodic water / electrolyte solution suitable storage (especially substantially under oxygen) problem-free be kept in stock for up to about six months.

below is the inventive method based on an embodiment a process for the treatment or disinfection of drinking water explained in more detail with reference to the drawings. It should be noted that the Preparation of electrochemically activated, anodic water / electrolyte solution in pure or otherwise diluted Form can happen in an identical electrolysis reactor. In show the drawings:

1 a schematic flow diagram of a method for the disinfection of water by electrochemical activation (ECA);

2 a detailed view shown in section of the electrolysis reactor according to 1 ; and

3 a detailed view shown in section of the mixer according to 1 ,

In the 1 schematically illustrated, suitable for continuous or semi-continuous implementation of a method according to the invention for the disinfection of water by electrochemical activation (ECA) under potential Controlled Anodic Oxidation (PAO) includes a main water line 1 in which the water to be disinfected is conveyed. The main water pipe 1 For example, it can be formed by a supply line of the water supply of a hospital, a business enterprise, a hotel or another gastronomic enterprise, by the circulation line of a swimming pool or the like. To the main water pipe 1 is a branch line 2 connected, which with a valve 3 , in particular in the form of a control valve, and with a filter 4 , in particular in the form of a fine filter having a hole width of, for example, about 80 to 100 microns, and over one below with reference to 3 explained in more detail mixer 5 in an also below with reference to 2 closer described electrolysis reactor 6 empties. About the branch line 2 is thus a means of the control valve 3 controllable partial flow of the main water line 1 subsidized water in the electrolyzer sereaktor 6 convertible, for example, a partial flow of the main water line 1 transported water in the order of 1/200 via the branch line 2 is branched off.

The mixer 5 is on the inlet side on the one hand with the branch line 2 on the other hand with a reservoir 7 for receiving an electrolyte solution, for example a substantially saturated sodium chloride solution, in association, which in the mixer 5 be mixed as homogeneously as possible and on a common, drain-side line 8th of the mixer 5 in the electrolysis reactor 6 reach. The one from the reservoir 7 in the mixer 5 leading line 9 is further with an in 1 Not shown dosing pump equipped to the in the branch line 2 supplied water to add a defined amount of electrolyte solution. As in particular from 3 it can be seen, is the mixer 5 formed in the present embodiment of a ball mixer, which ensures a constant uniform mixing of the water with the electrolyte solution. It essentially comprises an approximately cylindrical container 51 , at the opposite ends of the inlets 2 . 9 or the process 8th are connected and in which a bed of in 3 exemplary indicated spheres 52 or other bulk material through which the water and the electrolyte solution flow therethrough, the balls 52 be excited into vibrations and thereby ensure a very homogeneous mixing of water / electrolyte solution.

How the particular 2 it can be seen, includes the electrolysis reactor 6 an anode 61 Which coated with from one catalytically active ruthenium dioxide (RuO ₂₎ in the present embodiment, for example, a hollow pipe made of titanium is formed and to which the end of an external thread 61a the positive pole of a voltage source not shown can be connected. The electrolysis reactor 6 further comprises a cathode 62 which is also formed in the present embodiment by a hollow tube, within which the anode 61 is arranged coaxially. The cathode 62 is connected by means such as they enclosing the outside terminals (not shown) to the negative terminal of the not further transmitted voltage source. Coaxial to the anode 61 as well as to the cathode 62 and between these is one by means of sealing rings 63 sealed, tubular diaphragm 64 arranged, which between the anode 61 and the cathode 62 located annular reaction space in an anode compartment and separated into a cathode compartment. The diaphragm 64 prevents mixing of the liquid located in the anode compartment and cathode compartment, but allows a flow of current which, in particular, does not represent a great resistance for the migration of ions. The diaphragm 64 is formed in the present embodiment, for example, of porous zirconia (ZrO ₂ ).

The electrolysis reactor 6 also has two inlets 65a . 65b over which the from the mixer 5 over the line 8th leaking water / electrolyte solution in the reaction space of the reactor 6 , ie in its anode space and in the latter of this through the diaphragm 64 spatially separated cathode space, is fed. A designated, for example, about T-shaped branch is in 1 Not shown. Again, in particular 3 and moreover 1 can be seen, the electrolysis reactor 6 furthermore two outlets 66a . 66b on which the water / electrolytic solution after chemical activation in the reactor 6 is deducible from this. During the outlet 66a for discharging the electrochemically activated water / electrolyte solution from the anode compartment of the reactor 6 - ie for discharging the so-called "anolyte" - is used, the outlet serves 66b for Ab lead from the cathode compartment - ie for discharging the so-called "catholyte". Furthermore, it can be provided that when starting the electrolysis reactor 6 Over a period of time, the "anolyte", ie, the electrochemically activated, anodic water / electrolyte solution, is also discarded for initial quality degradation as long as the electrolysis reactor 6 has not yet reached its desired operating state, exclude.

Below are the geometric dimensions of the electrolysis reactor used here 6 in the form of a list:
Length of the cathode compartment: 18.5 cm;
Volume of the cathode compartment: 10 ml;
Area of the cathode: 92.4 cm ² ;
Length of the anode compartment: 21.0 cm;
Volume of the anode compartment: 7 ml;
Area of the anode: 52.7 cm ² ;
Distance between cathode and anode: approx. 3 mm (including diaphragm).

The electrolysis reactor 6 is operated, for example, with a water flow rate of 60 to 140 l / h, of course, larger throughputs are possible by larger reactors and / or more, parallel reactors are used. Preferably, the electrolysis reactor is running 6 always at full load, where it can be switched off as needed and peak loads can be intercepted by a further explained below storage tank for the electrochemically activated, anodic water / electrolyte solution.

As turn out 1 can be seen, the outlet opens 66b from the cathode compartment of the electrolysis reactor 6 in a gas separator 10 , from which the exhaust gas via an optionally provided exhaust pipe 11 is discharged while the catholyte itself, ie from the cathode compartment of the electrolysis reactor 6 discharged water / electrolyte solution, via a line 12 , eg in the sewage system of a municipal sewage system, is discharged. The outlet 66a from the anode compartment of the electrolysis reactor 6 flows into a storage tank 13 , from which the anolyte via a line 14 the main water pipe 1 can be added, which in the present embodiment via a bypass line 15 happening, which in each case by a downstream or upstream of the junction of the line 14 in the bypass line 15 by means of a control valve 16 . 17 is on and zuusteuerbar. Another control valve 18 is in the from the bypass line 15 bridged section of the main water line 1 arranged. In the storage tank 13 with the bypass line 15 the main water pipe 1 connecting line 14 is also a metering pump 19 provided, which for the controlled metered addition of the anolyte from the storage tank 13 in the main water pipe 1 serves. An exhaust pipe 20 flows out of the storage tank 20 in the exhaust pipe 11 from the gas separator 10 , The function of the bypass line 15 , to which the disinfectant is added, is that in the normal operation of the entire, in the main water line 1 guided water flow via the bypass line 15 can be guided and acted upon with the disinfectant. For maintenance and installation purposes, the bypass line 15 however, from the main water line 1 over the valves 16 . 17 be separated.

The electrolysis reactor 6 is further with a in 1 unspecified reproduced, controllable voltage source to between the anode 61 and the cathode 62 ( 2 ) to control the desired current flow measured by an ammeter (not shown). He also has egg nen eg in the outlet 66a for the anolyte arranged pH meter (also not shown), which alternatively, for example, in the storage tank 13 can be provided. For example, in the reactor 6 integrated controllable pump (also not shown) serves to controllably deliver the water / electrolyte solution through the electrolytic reactor, the pump controlling the volume flow and thus the residence time of the water / electrolyte solution in the reactor 6 controls. A likewise not shown reproduced control device, for example in the form of an electronic data processing unit, is arranged to control said parameters so as to be in the from the anode chamber of the reactor 2 over the outlet 66a exiting anolyte to maintain a pH between 2.5 and 3.5, preferably in the range of about 3.0, which can be done for example by means of PID controllers.

For cleaning the electrolysis reactor 6 is also a memory 21 for receiving cleaning liquid, for example acetic acid or the like, and - optionally - a memory 22 provided for receiving spent cleaning liquid, wherein one of the memory 21 in the reactor 6 leading supply line 23 with the inlets 65a . 65b of the reactor 6 (see. 2 ) as well as one from the reactor 6 in the store 22 leading derivative 24 with the outlets 66a . 66b of the reactor 6 (see. 2 ) is coupled as needed to the reactor 6 ie to flush both its cathode space and in particular its anode space. Alternatively, the cleaning solution, in particular in the case of acetic acid, can also be fed directly into a, for example, municipal sewage system.

To the life of the electrolysis reactor 6 To increase or to shorten its maintenance intervals, this can also be a in 1 Not shown softener can be pre-switched, which keeps the hardness of the water, for example, to a value of at most 4 °.

following is the operation of the device for disinfecting water by electrochemical activation (ECA) under potential-controlled anodic oxidation (PAO) briefly explained.

The electrolysis reactor 6 is first calibrated depending on the electrical conductivity or - in the present embodiment - in dependence on this about representative hardness of the water to be disinfected (which usually has a pH in the neutral range, ie from about 6 to 8) in order to achieve a pH of about 3 in the anode compartment of the reactor 6 suitable setpoint values of the current flowing between the electrodes and the volume flow through the reactor or the residence time of the water / electrolyte solution in the reactor 6 , in particular in the anode compartment thereof, in which the anolyte effective for disinfecting the water is produced, to erhal It basically applies that with increasing hardness (or electrical conductivity) of the water to be disinfected, a higher current and / or a lower volume flow (or a higher residence time) is required to one for setting a pH in the range of 3 to achieve appropriate conversion of the water / electrolyte solution on the occasion of their electrochemical activation. During calibration, first a volume flow through the reactor 6 adjusted, which approximately the specifications of the respective required volume flow through the reactor 6 - More precisely: the via the branch line 2 the reactor 6 supplied volume flow, here for example about 1/200 of the main water line 1 Guided stream of water - corresponds, which is mainly after the in the main water line 1 funded amount of the means of the over the line 14 in the main water pipe 1 returned anolyte (here, for example, about 1/400 of the main water line 1 in the main water pipe 1 guided stream of water, while about 1/400 of this stream is discarded in the form of the catholyte) to be disinfected water. Further, a current is adjusted, which by suitable metered addition of electrolyte solution from the reservoir 7 gives a pH in the range of 3 of the water / electrolyte solution on the occasion of the electrochemical activation. After the calibration has been carried out for different waters with different hardness, in the present embodiment, the following calibration lines for the static setpoint current (I _{soll, stat} ) or for the desired volume flow through the reactor 6 (V ' _shall ) receive: I should, stat = 0.418 A · Hardness [°] + 0.953 A; (I) V ' should = -0.95 l / h · hardness [°] + 43.80 l / h. (II)

After the aforementioned Kalibriergeraden have been determined, which is between the anode 61 and the cathode 62 of the electrolysis reactor 6 depending on the hardness of the water to be disinfected, the flow is adjusted to the corresponding setpoint. The same applies to the volume flow of the water / electrolyte solution through the reactor 6 therethrough.

During operation, the pH of the anolyte used to disinfect the water is always controlled so that the pH of the anolyte is in the range of 3, which in particular by additional control of the dynamic proportion (I _{soll, dyn} ) of the total electrodes 61 . 62 of the electrolysis reactor 6 applied total nominal current (I _{soll, ges} ) taking into account the actually measured volume flow (V ') through the reactor 6 happens: I should, ges = I should, stat + I should, dyn , (III) where I _{soll, dyn} = K ₇ * V '+ K ₈ . Consequently, depending on the measured pH of the electrodes to the electrodes 61 . 62 applied current increases as the pH increases above 3 (ie as the measured volumetric flow V 'increases or as the conversion achieved in electrochemical activation decreases) while the flow decreases as the pH falls below 3 (ie if the measured volumetric flow rate V 'decreases, for example owing to the formation of gas bubbles in the reaction space, or if the conversion achieved during the electrochemical activation increases); and / or the volumetric flow V 'through the reactor is reduced as the pH increases above 3 while the volumetric flow rate is increased as the pH falls below 3. While the amount of metered electrolyte solution is preferably kept substantially constant, it may alternatively or additionally be provided that more electrolyte solution from the reservoir 7 is metered in as the pH increases above 3 (ie, when the conversion achieved in electrochemical activation decreases), while less electrolyte solution is added as the pH falls below 3 (ie when the conversion achieved in electrochemical activation increases). , In particular, it is also possible according to the invention, two of the three aforementioned parameters current (ie, electrical current between the electrodes of the reactor 6 ), Volume flow through the reactor 6 through (ie volume flow of the water / electrolyte solution) and amount of metered electrolyte solution to keep constant and to keep the pH only by controlling the third parameter in the range according to the invention. The redox potential, which is set to a value in the range of 3 in the control of the pH according to the invention, is preferably approximately constant 1340 mV ± 20 mV.

The disinfecting liquid obtained in this way by the electrochemical activation controlled in accordance with the invention in the form of a potential-controlled anodic oxidation, which in the form of the anolyte in the storage tank 13 cached becomes the main water pipe 1 by means of the metering pump 19 Especially in a proportion of about 1: 400, to provide reliable disinfection of all the water delivered herein. Since the electrochemically activated anolyte, as already mentioned, is in a metastable state, it should in view of the largely unprotected and possibly warm storage with a relatively large free surface of the liquid level in the storage tank 13 a maximum of about 14 days, preferably a maximum of about 48 hours, in the storage tank 13 be kept in stock before being added to the water for the purpose of disinfection. However, as mentioned above, it is readily possible to store the disinfectant prepared in the aforesaid manner by itself for up to about six months for a gas-tight as possible conclusion appropriate storage tanks and preferably for the lowest possible temperature, for example, up to about 8 ° C should be taken care of.

Claims (34)

Method for the disinfection of water, such as drinking and service water, rainwater, industrial water and the like, by electrochemical activation (ECA) by at least a partial stream of water to be disinfected, an electrolyte solution, in particular a sodium chloride solution added and the acted upon with the electrolyte solution in a water Electrolysis Reactor ( 6 ) having at least one cathode compartment with a cathode ( 62 ) and at least one of the cathode space spatially, in particular by means of a diaphragm or a membrane, separate anode space with an anode ( 61 ) by applying a DC voltage to the electrodes ( 61 . 62 ) is applied to an electric current to put the water / electrolyte solution in a suitable for disinfection, metastable state, characterized in that the pH of the water / electrolyte solution in the anode chamber to a value between 2.5 and 3 , 5 is controlled. Method according to claim 1, characterized in that that the pH of the water / electrolyte solution in the anode space to a value between 2.7 and 3.3, in particular is controlled to a value between 2.8 and 3.2. Method according to claim 1 or 2, characterized that the pH of the water / electrolyte solution in the anode space is measured directly by means of a pH meter. Method according to one of claims 1 to 3, characterized in that the pH of the water / electrolyte solution in the anode space indirectly via the between the electrodes ( 61 . 62 ) flowing current is measured. Method according to one of claims 1 to 4, characterized in that the pH of the water / electrolyte solution in the anode compartment indirectly over the residence time (T _V ) and / or the flow rate (V ') thereof in or through the electrolysis reactor is measured. Method according to one of claims 1 to 5, characterized that the pH of the water / electrolyte solution in the anode compartment by controlled addition of the corresponding Amount of electrolyte solution is controlled. Method according to one of claims 1 to 6, characterized in that the pH of the water / electrolyte solution in the anode space by controlling the between the electrodes ( 61 . 62 ) flowing current is controlled. Method according to one of claims 1 to 7, characterized in that the pH of the water / electrolyte solution in the anode compartment by controlling the residence time (T _V ) and / or the flow rate (V ') thereof in or through the electrolysis reactor ( 6 ) is controlled. Method according to one of claims 1 to 8, characterized in that for controlling the pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor ( 6 ) to a pH between 2.5 and 3.5, in particular between 2.7 and 3.3, at a predetermined nominal current between the electrodes ( 61 . 62 ) of the electrolysis reactor ( 6 ) Is dependent on the particular composition of the water to be disinfected residence time (T _V) and / or dependent on the particular composition of the water volume flow (V ') (of the water / electrolyte solution in the reactor or through the electrolytic 6 ) is determined. Process according to Claim 9, characterized in that the residence time (T _V ) and / or the volume flow (V ') in or through the electrolysis reactor ( 6 ) is determined as a function of the conductivity (κ) and / or the hardness (H) of the water. A method according to claim 9 or 10, characterized in that the residence time (T _V ) and / or the volume flow (V ') according to a straight-line equation of the form T V = k 1 · Κ + k 2 and or V '= k 3 · H + k 4 where k ₁ , k ₂ , k ₃ and k _{4 are} reactor specific constants. Method according to one of claims 1 to 11, characterized in that for controlling the pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor ( 6 ) to a pH between 2.5 and 3.5, in particular between 2.7 and 3.3, for a given residence time (T _V ) of the water / electrolyte solution in the electrolysis reactor ( 6 ) and / or at a predetermined volume flow (V ') of the water / electrolyte solution through the electrolysis reactor ( 6 ) one of each. Composition of the water to be disinfected depending, static target current (I _{soll, stat} ) between the electrodes ( 61 . 62 ) is determined. Method according to claim 12, characterized in that the static nominal current (I _{soll, stat} ) is determined as a function of the conductivity (κ) and / or of the hardness (H) of the water. A method according to claim 12 or 13, characterized in that the static nominal current I _{soll, stat} according to a straight-line equation of the form I should, stat = K 1 · Κ + K 2 and or I should, stat = K 3 · H + K 4 where K ₁ , K ₂ , K ₃ and K _{4 are} reactor specific constants. Method according to one of claims 12 to 14, characterized in that for controlling the pH of the water / electrolyte solution in the anode compartment of the electrolysis reactor ( 6 ) to a pH between 2.5 and 3.5, in particular between 2.7 and 3.3, at a predetermined static nominal current (I _{soll, stat} ) between the electrodes ( 61 . 62 ) of the electrolysis reactor ( 6 ) one of the respective residence time (T _V ) of the water / electrolyte solution in the electrolysis reactor and / or the respective volume flow of the water / electrolyte solution through the electrolysis reactor ( 6 ) dependent, dynamic setpoint current (I _{soll, dyn} ) is determined. A method according to claim 15, characterized in that the dynamic setpoint current (I _{soll, dyn} ) according to a straight-line equation of the form I should, dyn = K 5 * T V + K 6 and or I should, dyn = K 7 · V '+ K 8th where K ₅ , K ₆ , K ₇ and K _{8 are} reactor specific constants. Method according to one of Claims 12 to 16, characterized in that the electrodes ( 61 . 62 ) of the electrolysis reactor ( 6 ) a total nominal current (I _{soll, ges} ) is applied, which is formed from the sum of the static desired current (I _{soll, stat} ) and the dynamic reference current (I _{soll, dyn} ): I should, ges = I should, stat + I should, dyn Method according to one of claims 9 to 17, that the amount on dosed electrolyte solution is kept substantially constant. Method according to one of claims 1 to 18, characterized that the electrolyte solution added in the form of a substantially saturated sodium chloride solution becomes. Method according to one of claims 1 to 19, characterized that only the in the anode space generated, electrochemically activated water / electrolyte solution for Disinfection of the water is used. Method according to one of claims 1 to 20, characterized that out a partial flow diverted to the water to be disinfected, the partial flow electrochemically activated and at least electrochemically in the anode compartment activated partial flow to be disinfected water as a disinfectant is added. Method according to one of claims 1 to 21, characterized that it is carried out continuously or semicontinuously. Process for the preparation of a disinfectant by electrochemical activation (ECA) of water by adding to the water an electrolyte solution, in particular a sodium chloride solution, and adding the water, which has been treated with the electrolyte solution, to an electrolysis reactor ( 6 ) having at least one cathode compartment with a cathode ( 62 ) and with at least one of the Ka tnodenraum spatially, in particular by means of a diaphragm or a membrane, separate anode space with an anode ( 61 ) by applying a DC voltage to the electrodes ( 61 . 62 ) is applied to an electric current to put the water / electrolyte solution in a suitable for disinfection, metastable state, characterized in that the pH of the water / electrolyte solution in the anode chamber to a value between 2.5 and 3 5, wherein the disinfectant is obtained in the form of the thus electrochemically activated anodic water / electrolytic solution. A method according to claim 23, characterized by the features of at least one of claims 2 to 19 and 22. Method according to claim 23 or 24, characterized that this Disinfectant in the form of the electrochemically activated, anodic electrolyte solution in in substantially pure form or in the form of a dilution of up to 1: 500, in particular up to 1: 400, proportions of a diluent, especially water, is used. Disinfectants made by a process according to one the claims 22 to 25. Use of a disinfectant according to claim 26 for the disinfection of water, such as and service water, rainwater, industrial water and the like. Use of a disinfectant according to claim 26 for the disinfection of food such as cereals, spices, fruit, Vegetables, Ice cream, animal products and the same. Use of a disinfectant according to claim 26 for the disinfection of seeds. Use of a disinfectant according to claim 26 for the disinfection of packaging containers and packaging, in particular for hygienic Products such as food, pharmaceuticals, sterile items and like. Use of a disinfectant according to claim 26 as an additive for Reaction media to carry out of solvent and emulsion polymerizations. Use of a disinfectant according to claim 26 as an additive for Paints, varnishes and pigments. Use of a disinfectant according to claim 26 as an additive for Cold and Lubricant. Use of a disinfectant according to claim 26 as an additive for Fuels and fuels, such as fuel oil, Gasoline, kerosene and the like.