WO2014064571A1

WO2014064571A1 - Device and a method for preparing an oxidative solution

Info

Publication number: WO2014064571A1
Application number: PCT/IB2013/059295
Authority: WO
Inventors: Jianyu JIN; Guangwei Wang; Peixin Hu
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2012-10-23
Filing date: 2013-10-11
Publication date: 2014-05-01
Anticipated expiration: 2015-04-23

Abstract

The present invention provides a device for preparing an oxidative liquid, comprising: an oxidant source 12a (i.e. a second electrolysis unit) configured to provide an oxidant to a liquid; and a pH adjuster 14a (i.e. a first electrolysis unit) configured to adjust pH of the liquid to adjust an activity of the oxidant in the liquid. The pH value of the oxidative liquid can be effectively controlled by means of the device and method for preparing an oxidative liquid of the present invention, and by controlling a voltage and/or an electrical current applied on the first electrolysis unit 14a so as to adjust the oxidative activity of the oxidative liquid conveniently. In addition, the first electrolytic chamber or the second electrolytic chamber of the first electrolysis unit 14a of the present invention is arranged with a reactant capable of reacting with the H+ ions or OH- ions, which facilitates elimination of waste water discharge, and is environment friendly.

Description

DEVICE AND A METHOD FOR PREPARING AN OXIDATIVE SOLUTION

FIELD OF THE INVENTION

The present invention relates to the field of preparation of an oxidative solution.

BACKGROUND OF THE INVENTION

Oxidative solution such as oxidative water generally comprising oxidants such as H₂0₂, HCIO and KMn0₄ are widely used in, for example, family life, industrial production as well as diagnosis and treatment process in hospitals. The oxidative water can be used in washing and cleaning, disinfection and sterilization, blanching and whitening, waste water treatment,etc.

In general, the oxidative water is obtained by dissolving oxidants in water. For example, dissolving Ca(C10)₂ into water to get CIO^" solution for blanching; filling Cl₂ gas into water to get HCIO solution to kill the bacteria in water; or diluting H₂0₂ (e.g., 30 wt% H₂0₂ is commercially available) into water to get H₂0₂ solution for teeth whitening, etc.

However, there are still many defects in the methods for getting the oxidative water in the prior art. Most of the oxidants, such as 30 wt% H₂0₂, NaClO etc., are caustic and dangerous for people to operate with.

Secondly, users may need water with different oxidabilities, e.g., water with relatively strong oxidability for quick washing, water with relatively weak oxidability for long time storage to avoid damages caused by the oxidants. However, the oxidability of oxidative water prepared as aforementioned cannot be changed after the preparation. In addition, the preparation of these oxidative water is complex, cost ineffective and environment unfriendly. Therefore, there is a desideration of a new device and method for preparing an oxidative water in the art.

SUMMARY OF THE INVENTION In view of this, the present invention provides a device for preparing an oxidative liquid which can solve or at least release at least some of the defects in the prior art. The device for preparing an oxidative liquid may comprise: an oxidant source configured to provide an oxidant to a liquid; and a pH adjuster configured to adjust pH of the liquid to adjust an activity of the oxidant in the liquid. In embodiments of the invention, users no longer need to add the oxidant into the liquid (e.g., water) manually therefore the risk for the users to get hurt by the oxidant is mitigated.

In one embodiment of the present invention, the device for preparing an oxidative liquid may further comprise: a user interface configured to select a desired activity of the oxidant in the liquid; a controller configured to control the pH adjuster such that the oxidant in the liquid has the desired activity. In an embodiment, the user interface of the device may comprises a button array which include buttons each marked with corresponding instructions, "washing/cleaning", "disinfection/sterilization",

"blanching/whitening", "waste water treatment", etc. Each button is further associated with a preset target/desired oxidant activity. Therefore, the user can easily choose according to his/her needs and get liquid including oxidant with a desired activity.

In a further embodiment of the present invention, wherein the pH adjuster comprises a first electrolysis unit, the controller is configured to control a voltage and/or an electrical current applied on the first electrolysis unit. Since the pH value of the oxidative liquid is related to the oxidizability of the oxidative liquid, the oxidative activity of the oxidative liquid can be conveniently adjusted.

In another embodiment of the present invention, wherein the first electrolysis unit comprises a first electrolytic chamber with a first electrode and a second electrolytic chamber with a second electrode, wherein the first electrolytic chamber generates OH^" ions and the second electrolytic chamber generates H ions, or the first electrolytic chamber generates H⁺ ions and the second electrolytic chamber generates OH^" ions.

In yet another embodiment of the present invention, wherein the first electrolytic chamber or the second electrolytic chamber is arranged with a reactant capable of reacting with the H⁺ ions or OH^" ions. Thus it will facilitates elimination of waste water discharge, and is environment friendly.The reactant also allows the user to use the device even there is no drainpipe, because it no longer produce waste water with very high/low pH which blocks further electrolyze.

In one embodiment of the present invention, wherein the first electrode or the second electrode is made of the reactant.

In a further embodiment of the present invention, wherein the first electrolysis unit further comprises a first liquid input for inputting liquid, such as water, and a first liquid output for outputting the H⁺ ions and/or OH^" ions, wherein the oxidant source comprises a second electrolysis unit with a second liquid input for inputting a liquid, a third electrode and a fourth electrode for generating the oxidant in the liquid, and a second liquid output for outputting the liquid containing the oxidant, and wherein the outputted H⁺ ions or OH^" ions reacts with the oxidant contained in the liquid.

In another embodiment of the present invention, wherein the first electrolysis unit further comprises a first liquid input for inputting liquid, such as water, and a first liquid output for outputting the H⁺ ions and/or OH^" ions, wherein the oxidant source comprises a second electrolysis unit with a second liquid input for inputting a liquid, a second electrode and a fourth electrode for generating the oxidant in the liquid, and a second liquid output for outputting the liquid containing the oxidant, wherein the second electrode is shared by the first electrolysis unit and the second electrolysis unit, and wherein the outputted H⁺ ions or OH^" ions reacts with the oxidant contained in the liquid.

According to a second aspect of the present invention, it provides an apparatus comprising a device for preparing an oxidative liquid as stated above. According to a third aspect of the present invention, it provides a method for preparing an oxidative liquid, comprising the steps of: providing an oxidant to a liquid; and adjusting pH of the liquid to adjust an activity of the oxidant in the liquid.

In one embodiment of the present invention, wherein the adjusting step may further comprise: selecting a desired activity of the oxidant in the liquid before providing the oxidant to a liquid; adjusting pH of the liquid comprising controlling the adjusting such that the oxidant in the liquid has the desired activity.

In a further embodiment of the present invention, wherein the controlling step further comprises: controlling a voltage and/or an electrical current applied. The pH value of the oxidative liquid can be effectively controlled by means of the device and method for preparing an oxidative liquid of the present invention, and by controlling a voltage and/or an electrical current applied on the first electrolysis unit, e.g., a voltage and/or an electrical current applied on the first electrode and the second electrode. Since the pH value of the oxidative liquid is related to the oxidizability of the oxidative liquid, the oxidative activity of the oxidative liquid can be conveniently adjusted. Alternatively, in some embodiments, the first electrolytic chamber or the second electrolytic chamber is arranged with a reactant capable of reacting with the H⁺ ions or OH^" ions, which facilitates elimination of waste water discharge, and is environment friendly.The reactant also allows the user to use the device even there is no drainpipe, because it no longer produce waste water with very high/low pH which blocks further electrolyze.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 A schematically shows a device for preparing an oxidative liquid according to one embodiment of the present invention. Fig. IB schematically shows a device for preparing an oxidative liquid according to a further embodiment of the present invention.

Fig. 1C schematically shows a device for preparing an oxidative liquid according to another embodiment of the present invention. Fig. ID schematically shows a layout of a device for preparing an oxidative liquid according to one embodiment of the present invention.

Fig. IE schematically shows a layout of a device for preparing an oxidative liquid according to another embodiment of the present invention. Fig. 2 schematically shows a block diagram of a device for preparing an oxidative liquid according to one embodiment of the present invention.

Fig. 3A schematically shows a block diagram of a device for preparing an oxidative liquid according to a further embodiment of the present invention.

Fig. 3B schematically shows a schematic diagram of input and output of electrolyzed water in the case of not using the reactant.

Fig. 3C schematically shows a schematic diagram of input and output of electrolyzed water in the case of using the reactant.

Fig. 4A schematically shows a flow chart of a method for preparing an oxidative liquid according to a further aspect of the present invention. Fig. 4B schematically shows a flow chart of a method for preparing an oxidative liquid according to one embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Respective embodiments of the present invention will be described in detail below with reference to the drawings of the present invention.

It shall be noted that although the present invention is described by taking the example of adding oxidants in water to prepare oxidative water, the skilled person in the art should understand that the present invention is not limited to the case of preparing oxidative water. For example, it can be preparation of oxidative organic solvent and substances the oxidizability of which can be adjusted, etc. The oxidizability of an oxidant is related to the standard electrode potential of the oxidant, and the standard electrode potential is also associated with the pH value of the solution, thus the oxidizability of the oxidant is also associated with the pH value of the solution. For example, the standard electrode potential of HCIO in 25°C acidic aqueous solution is 1.48V, while the standard electrode potential in 25°C alkaline aqueous solution is 0.841V; the standard electrode potential of 0₃ in 25°C acidic aqueous solution is 2.08V, while the standard electrode potential in 25°C alkaline aqueous solution is 1.24V. It can be seen from the above introduction that the standard electrode potentials of these oxidants in acidic (i.e., with a pH less than 7) aqueous solution are greater than the standard electrode potentials in alkaline (with a pH greater than 7) aqueous solution, which indicates that these substances have stronger oxidizability in acidic aqueous solution than in alkaline aqueous solution. That is, the oxidizability of the oxidant is associated with the pH value of the solution.

In order to characterize the oxidizability level of the oxidative liquid accurately, the oxidation/reduction potential (ORP) can be used to replace the standard electrode potential for characterization. Further improvements are set forth below referring to embodiments of the invention.

Fig. 1A schematically shows a device 10 for preparing an oxidative liquid according to one embodiment of the present invention. The device 10 may comprise an oxidant source 12 configured to provide an oxidant to a liquid; and a pH adjuster 14 configured to adjust pH of the liquid to adjust an activity of the oxidant in the liquid. In embodiments of the invention, the oxidant source 12 as such can be able to generate oxidant and provide the same to the liquid when needed, or can be a container without any oxidant generation function, thus user needs to fill the source 12 with oxidant manully accordingly. Fig. 1A shows that an oxidant is provided to the oxidant source 12 via an input I (e.g., an opening on the device 10). The oxidant source 12 may be a source that provides H₂0₂, Cl₂, HCIO, I₂, KMn0₄, and 0₃ etc., to liquids such as water. For example, the oxidant source 12 provides HCIO first, and then the pH adjuster 14 adjusts the pH value of the aqueous solution containing HCIO, so as to adjust the oxidizability of the aqueous solution containing HCIO. Then the adjusted HCIO aqueous solution with a desired oxidizability is outputted via an output O. In embodiments of the invention, the device 10 can be standalone in kitchen, washroom, living room or elsewhere, provided with water to prepare oxidative water. In other embodiments, the device 10 could be a part of an appliance such as a rice cooker, a coffee maker, a washing machine, etc., and configured to provide water with appropriate oxidability. It should be noted though water is taken as an example of liquid herein, other liquid that can be used to prepare oxidative liquid can also be used together with/instead of water.

Alternatively, referring to Fig. IB, the pH of the raw water can be changed by the pH adjuster 14 first before being provided with the oxidant by the source 12.

For example, in order to get HCIO aqueous solution with stronger oxidizability, the pH adjuster 14 firstly decreases the pH value of the water by adding H⁺ ions therein and then the acidic water is provided with HCIO by the source 12. In order to get HCIO aqueous solution with weaker oxidizability, the pH adjuster 14 firstly increases the pH value of the water by adding OH^" ions therein and then the alkaline water is provided with HCIO by the source 12, where the oxidability of HCIO is restrained.

Fig. 1C schematically shows a device 30 for preparing an oxidative liquid according to an alternative embodiment of the present invention, wherein the oxidant source 12 provides HCIO and the pH adjuster 14 provides an appropriate amount of H⁺ ions and/or OH^" ions simultaneously, the mixture of the two reacts to produce a HCIO aqueous solution with a desired oxidizability.

In one embodiment of the present invention, the device for preparing an oxidative liquid may further comprises: a user interface 16 configured to select a desired activity of the oxidant in the liquid; a controller 18 configured to control the pH adjuster 14 such that the oxidant in the liquid has the desired activity, as shown in Figs. ID and IE. The difference as shown in Figs. ID and IE only lies in that it indicates the positions of the oxidant source 12 and the pH adjuster 14 can interchange. That is, in the case as shown in Fig. ID, the oxidant source 12 provides HCIO oxidant to the pH adjuster 14, then the pH adjuster 14 provides an appropriate amount of water containing H⁺ ions and/or OH^" ions to the HCIO oxidant based on the control instruction of the controller 18, so as to adjust the oxidative activity of the HCIO oxidative liquid. Whereas in another case as shown in Fig. IE, the pH adjuster 14 provides an appropriate amount of water containing H⁺ ions and/or OH^" ions to the HCIO oxidant directly based on the control instruction of the controller 18, so as to adjust the oxidative activity of the HCIO oxidative liquid. A key button may be arranged in the user interface 16, which characterizes for example the five options of weak, relatively weak, neutral, relatively strong, strong of the oxidative activity. Of course, various other key button options, e.g., washing/cleaning, disinfection/sterilization, blanching/whitening, waste water treatment, etc., may also be set based on needs, for the convenience of user to use. In the event that the desired activity of the HCIO has be selected, the controller 18 controls the pH adjuster 14 based on the selected desired activity, that is, controlling the amount of the H⁺ ions and/or OH^" ions released by the pH adjuster 14, so that the HCIO aqueous solution has the desired activity. For example, in the case of selecting the key button of "relatively strong", an appropriate amount of water containing H⁺ ions is added into the HCIO oxidant to enhance the oxidizability of the HCIO oxidant solution. For example, if the mode as shown in Fig. ID is adopted, the HCIO oxidant source may provide HCIO firstly, and then the pH adjuster 14 provides an appropriate amount of water containing H⁺ ions based on the instruction of the controller 18, so as to enhance the oxidizability of the HCIO oxidative solution. If the mode as shown in Fig. IE is adopted, the pH adjuster 14 provides an appropriate amount of water containing H⁺ ions directly based on the instruction of the controller 18, so as to enhance the oxidizability of the HCIO oxidative solution. The skilled person in the art should learn that the above description is made in the case of selecting the key button of "relatively strong". In the case of selecting other key buttons, the device for preparing an oxidative liquid may perform the corresponding operation, which will not be elaborated here.

Fig. 2 schematically shows a block diagram of a device for preparing an oxidative liquid according to one embodiment of the present invention. The pH adjuster 14 may comprises a first electrolysis unit 14a, the controller 18 is configured to control a voltage and/or an electrical current applied on the first electrolysis unit 14a. The first electrolysis unit 14a may comprise a first electrolytic chamber I with a first electrode 22 and a second electrolytic chamber II with a second electrode 24, wherein the first electrolytic chamber I generates OH^" ions and the second electrolytic chamber II generates H⁺ ions, or the first electrolytic chamber I generates H⁺ ions and the second electrolytic chamber II generates OH^" ions. For example, in the case of using tap water as the electrolyte in the first electrolysis unit 14a, the following reactions will occur:

In the proximity of the first electrode 22 as the anode:

2H₂0-4e=4H⁺+0₂

In the proximity of the second electrode 24 as the cathode: 4H₂0+4e=2H₂+40H^"

Namely, H⁺ ions are generated in the proximity of the first electrode 22, while OH^" ions are generated in the proximity of the second electrode 24. According to the function selected by the user in the user interface 16 and the oxidant that need to be adjusted, an appropriate amount of water containing H⁺ ions or OH^" ions is provided to the oxidant that need to be adjusted.

Here, it should be noted that the inventor of the present invention recognizes for the first time that the pH value of the HCIO aqueous solution can be conveniently controlled by controlling a voltage and/or an electrical current applied on the first electrolysis unit 14a, i.e., a voltage and/or an electrical current applied on the first electrode 22 and the second electrode 24, so as to control the oxidizability of the HCIO aqueous solution conveniently. For example, the relation between the values of the applied voltage and/or the electrical current and the oxidation reduction potential that

characterizes the oxidizability of the oxidative HCIO can be stored in the controller 18 in advance. Alternatively, in a modificative embodiment, a storage (not shown) can be arranged in the controller 18, or the storage is a separate element, or the storage is integrated with the controller 18, or the controller 18 itself is a controller with the storing function for pre-storing the relation among the voltage and/or electrical current value of a particular oxidant in a particular situation, the corresponding pH value, and the

corresponding oxidation reduction potential. Generally speaking, the greater positive value the oxidation reduction potential is, the stronger the oxidizability of the oxidative liquid is. The relation among the voltage and/or electrical current value of a particular oxidant in a particular situation, the corresponding pH value, and the corresponding oxidation reduction potential will be further described in detail below.

The first electrolysis unit 14a as shown in Fig. 2 may further comprise a first liquid input 28 for inputting water, and a first liquid output 32 for outputting the FT ions and/or OH^" ions. The oxidant source 12 may further comprise a second electrolysis unit 12a with a second liquid input 34 for inputting a liquid, a third electrode 36 and a fourth electrode 38 for generating the oxidant in the liquid, and a second liquid output 39 for outputting the liquid containing the oxidant. The H⁺ ions or OH^" ions outputted from the first liquid output 32 react with the HCIO liquid containing the oxidant HCIO outputted from the second liquid output 39.

For example, in the case of inputting tap water at the first liquid input 28 of the first electrolysis unit 14a, the following reactions will occur:

In the proximity of the first electrode 22 as the anode:

2H₂0-4e=4H⁺+0₂

For example, in the case of inputting tap water containing CI^" ions at the second liquid input 34 of the second electrolysis unit 12a, the following reactions will occur:

In the proximity of the fourth electrode 38 as the anode: 2Cl^"-2e=Cl₂

In the proximity of the third electrode 36 as the cathode: 2H₂0+4e=2H₂+40H^" However, the CI2 will transform to CIO^" in the alkaline water through a disproportion reaction:

In a modificative embodiment of the present invention, the first electrolytic chamber I or the second electrolytic chamber II is arranged with a reactant 26 capable of reacting with the H⁺ ions or OH^" ions, so as to avoid production of waste water. Fig. 3A schematically chamber shows that the first electrolytic I is arranged with a reactant 26 capable of reacting with the H⁺ ions or OH^" ions. For example, in the case of electrolyzing the tap water in the first electrolysis unit 14a to get water containing the OH^" ions as the pH regulator, the following reaction occurs in the proximity of the second electrode 24 as the cathode: 2H₂0+2e=H₂+20H^". The water containing the OH^" ions will be outputted via the first liquid output 32. Whereas the following reaction will occur in the proximity of the first electrode 22 as the anode: 2H₂0-4e=4H⁺+0₂. In the case of adjusting downwards the HCIO oxidizability, the water containing H⁺ ions might be unwanted. In general cases, people usually discharge the water containing H⁺ ions or OH^" ions as waster water, which goes against saving of water resources and also increase cost. Both Figs. 2 and 3B show the case of discharging waste via the liquid output 32'. The inventor of the present invention realizes that the first electrolysis chamber I is arranged with a reactant 26, e.g. CaC03, capable of reacting with the H⁺ ions, for reacting with the H⁺ ions:

CaC0₃+2H=Ca² +H₂0+C0₂, so as to transform the unwanted H⁺ ions into water for recycle use, which eliminates the discharge of waster water. Said situation is shown in Fig. 3C.

The skilled person in the art should understand that the reactant 26 used in the particular embodiment of the present invention is not limited to CaC0₃. The reactant 26 may be various chemical substances that can react with the unwanted H⁺ ions or OH^" ions in the solution. For example, the reactant 26 can be metal oxidizes (MgO, ZnO, A1₂0₃, Fe₂0₃ etc.), carbonates (CaC0₃, MgC0₃, etc.), hydroxides (Mg(OH)₂, Al(OH)₃, Fe(OH)₃ etc.), polymers (cation or anion exchange resins etc.) or any other substance that can react with H⁺ or OH^". The reactants used in the particular embodiment of the present invention can also be solids, liquids, solutions, gels, gas etc. For example, the selected phosphate buffer solution (PBS) can be a kind of solution reactant for maintaining the neutral pH in counter chamber, and the selected carbon dioxide can be a kind of gaseous reactant for consuming the unwanted OH^". In the particular embodiment of the present invention, the reactants can be filled in the counter chamber, or combined with the electrode, or used as electrodes. In one embodiment of the present invention, the first electrode 22 or the second electrode 24 can be made of the reactant 26.

In one modificative embodiment of the present invention, the device for preparing an oxidative liquid can also be designed as follows. Namely, the first electrolysis unit 14a may comprise a first liquid input 28 for inputting water, and a first liquid output 32 for outputting the H⁺ ions and/or OH^" ions, wherein the oxidant source 12 comprises a second electrolysis unit 12a with a second liquid input 34 for inputting a liquid, a second electrode 24 and a fourth electrode 38 for generating the oxidant in the liquid, and a second liquid output 39 for outputting the liquid containing the oxidant, wherein the second electrode 24 is shared by the first electrolysis unit 14a and the second electrolysis unit 12a (such a situation is not shown in the figure), and the outputted H⁺ ions or OH^" ions reacts with the oxidative liquid. The second electrode 24 is shared by the first electrolysis unit 14a and the second electrolysis unit 12a in order to reduce the use number of the electrodes, so that the shared second electrode 24 can be simultaneously used as the anode or cathode of the first electrolysis unit 14a and the second electrolysis unit 12a. In the case of electro lyzing water etc., noble metal electrodes such as Pt electrode need to be used to reduce the use number of the electrodes, which facilitates reduction of cost of the device for preparing an oxidative liquid.

According to a second aspect of the present invention, an apparatus comprising a device for preparing an oxidative liquid as stated above can be provided.

According to a third aspect of the present invention, a method 40 for preparing an oxidative liquid can be provided, comprising the steps of: providing 42 an oxidant to a liquid; and adjusting 44 pH of the liquid to adjust an activity of the oxidant in the liquid, as shown in Fig. 4 A. In one embodiment of the present invention, the method 40 for preparing an oxidative liquid may further comprise the steps of: selecting 46 a desired activity of the oxidant in the liquid before providing 42 the oxidant to a liquid; adjusting 44 pH of the liquid comprising controlling 48 the adjusting such that the oxidant in the liquid has the desired activity, as shown in Fig. 4B.

In a further embodiment of the present invention, the step of controlling 48 the adjusting such that the oxidant in the liquid has the desired activity may further comprise: controlling a voltage and/or an electrical current applied. In particular, controlling a voltage and/or an electrical current applied on the first electrode 22 and the second electrode 24 in the first electrolysis unit 14a.

In order to make the skilled person in the art to understand the details of the present invention more clearly, several schematic embodiments will be illustrated below.

First Embodiment

Solutions with different oxidative activities are generated by controlling the voltage applied on the first electrolysis unit 14a, i.e., the voltage applied on the first electrode 22 and the second electrode 24. The first electrolysis unit 14a used in the first embodiment is a conventional water electrolysis unit.

The 1% NaCl solution is provided to the second electrolysis unit 12a via the second liquid input 34, and is outputted via the second liquid output 39, the voltage applied between the third electrode 36 and the fourth electrode 38 is 10V, in this way, an electrical current of 2.45A flowing through the third electrode 36 and the fourth electrode 38 is generated.

The NaS0₄ of 2mM is provided to the first electrolysis unit 14a via the first liquid input 28, and the wanted H⁺ ions or OH^" ions are outputted via the first liquid output 32. The first electrolysis unit 14a comprises a first electrolysis chamber I and a second electrolysis chamber II, the flow rates of the NaS0₄ solutions in said two electrolysis chambers are equal, both are 50ml/min, thus the total flow rate of the NaS0₄ solution in the first electrolysis unit 14a is 50ml/min + 50ml/min = lOOml/min.

Table 1 shows the solutions with different oxidative activities in the case of controlling the voltage (voltage applied between the first electrode 22 and the second electrode 24) applied on the first electrolysis unit 14a in the first embodiment.

It can be seen from the above experimental results that the greater the voltage applied between the first electrode 22 and the second electrode 24 is, the smaller the pH value of the outputted NaCl solution while the greater the oxidation reduction potential is, it means that the oxidizability of the NaCl solution becomes stronger and stronger. The above Table 1 has shown the corresponding values of the currents flowing through the first electrode 22 and the second electrode 24. It is easy for the skilled person in the art to understand that solutions with different oxidative activities can also be generated by controlling the values of the currents flowing through the first electrode 22 and the second electrode 24.

Second Embodiment

The first electrolysis unit 14a used in the second embodiment is a reactant-assisted water electrolysis unit. The 1% NaCl solution is provided to the second electrolysis unit 12a via the second liquid input 34, and is outputted via the second liquid output 39, the voltage applied between the third electrode 36 and the fourth electrode 38 is 10V, in this way, an electrical current of 2.45 A flowing through the third electrode 36 and the fourth electrode 38 is generated.

The phosphate buffer solution (PBS) of 150ml, 0.1 mol/L, pH=7, is filled in the first electrolysis chamber I of the first electrolysis unit 14a, as shown in Fig. 3 A. The phosphate buffer solution is filled in the first electrolysis chamber I in order to avoid generating waster water in the subsequent electrolysis process. The NaS0₄ of 2mM is provided to the first electrolysis unit 14a via the first liquid input 28, and the wanted H⁺ ions or OH^" ions are outputted via the first liquid output 32. The first electrolysis unit 14a comprises a first electrolysis chamber I and a second electrolysis chamber II, the flow rate of the NaS0₄ solution in the second electrolysis chamber II is 50ml/min, while the NaS0₄ solution in the first electrolysis chamber I is recycled by reacting with the phosphate buffer solution. This means that the flow rate of the NaS0₄ solution in the first electrolysis chamber I is Oml/min.

Table 2 shows the solutions with different oxidative activities in the case of controlling the voltage (voltage applied between the first electrode 22 and the second electrode 24) applied on the first electrolysis unit 14a in the second embodiment.

Voltage Applied Current at the first pH of Output ORP of Output

(V) electrolysis cell (A) Solution Solution (mV)

-30 1.48 11.39 68

-20 0.94 11.17 152

-10 0.34 10.84 273

0 0 8.95 644

10 0.44 6.50 849

20 1.40 2.76 1137

30 2.70 2.45 1151 It can be seen from the above experimental results that the greater the voltage applied between the first electrode 22 and the second electrode 24 is, the smaller the pH value of the outputted NaCl solution while the greater the oxidation reduction potential is, it means that the oxidizability of the NaCl solution becomes stronger and stronger. The above Table 2 has shown the corresponding values of the currents flowing through the first electrode 22 and the second electrode 24. It is easy for the skilled person in the art to understand that solutions with different oxidative activities can also be generated by controlling the values of the currents flowing through the first electrode 22 and the second electrode 24.

Although the present invention has been described with reference to the currently considered embodiments, it should be understood that the present invention is not limited to the disclosed embodiments. On the contrary, the present invention aims to cover various modifications and equivalent arrangements comprised within the spirit and scope of the claims as attached. The scope of the following claims complies with the broadest explanation so as to comprise all such modifications and equivalent structures and functions.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

A device (10, 20, 30) for preparing an oxidative liquid, comprising: an oxidant source (12) configured to provide an oxidant to a liquid; and a pH adjuster (14) configured to adjust pH of the liquid to adjust an of the oxidant in the liquid.

The device (10, 20, 30) according to claim 1 , further comprising: a user interface (16) configured to select a desired activity of the oxidant in the liquid; a controller (18) configured to control the pH adjuster (14) such that the oxidant in the liquid has the desired activity.

3. The device (10, 20, 30) according to claim 2, wherein the pH adjuster (14) comprises a first electrolysis unit (14a), the controller (18) is configured to control a voltage and/or an electrical current applied on the first electrolysis unit (14a).

4. The device (10, 20, 30) according to claim 3, wherein the first electrolysis unit (14a) comprises a first electrolytic chamber (I) with a first electrode (22) and a second electrolytic chamber (II) with a second electrode (24), wherein the first electrolytic chamber (I) generates OH^" ions and the second electrolytic chamber (II) generates H⁺ ions, or the first electrolytic chamber (I) generates H⁺ ions and the second electrolytic chamber (II) generates OH^" ions.

1

5. The device (10, 20, 30) according to claim 4, wherein the first electrolytic chamber (I) or the second electrolytic chamber (II) is arranged with a reactant (26) capable of reacting with the H⁺ ions or OH^" ions.

6. The device (10, 20, 30) according to claim 5, wherein the first electrode (22) or the second electrode (24) is made of the reactant (26).

7. The device (10, 20, 30) according to claim 4, wherein the first electrolysis unit (14a) further comprises a first liquid input (28) for inputting water, and a first liquid output (32) for outputting the H⁺ ions and/or OH^" ions, wherein the oxidant source (12) comprises a second electrolysis unit (12a) with a second liquid input (34) for inputting a liquid, a third electrode (36) and a fourth electrode (38) for generating the oxidant in the liquid, and a second liquid output (39) for outputting the liquid containing the oxidant, and wherein the outputted H⁺ ions or OH^" ions reacts with the oxidant contained in the liquid.

8. The device (10, 20, 30) according to claim 4, wherein the first electrolysis unit (14a) further comprises a first liquid input (28) for inputting water, and a first liquid output (32) for outputting the H⁺ ions and/or OH^" ions, wherein the oxidant source (12) comprises a second electrolysis unit (12a) with a second liquid input (34) for inputting a liquid, a second electrode (24) and a fourth electrode (38) for generating the oxidant in the liquid, and a second liquid output (39) for outputting the liquid containing the oxidant, wherein the second electrode (24) is shared by the first electrolysis unit (14a) and the second electrolysis unit (12a), and wherein the outputted H⁺ ions or OH^" ions reacts with the oxidant contained in the liquid.

9. An apparatus comprising the device (10, 20, 30) claimed in any one of claims 1 to 8.

10. A method (40) for preparing an oxidative liquid, comprising: providing (42) an oxidant to a liquid; and adjusting (44) pH of the liquid to adjust an activity of the oxidant in the liquid.

1 1 The method (40) according to claim 10, further comprising: selecting (46) a desired activity of the oxidant in the liquid before providing (42) the oxidant to a liquid; adjusting (44) pH of the liquid comprising controlling (48) the adjusting such that the oxidant in the liquid has the desired activity.

12. The method (40) according to claim 1 1 , wherein the controlling (48) further comprises: controlling a voltage and/or an electrical current applied.