Patent Application
20150336819
The present invention relates to an ion absorption/desorption device and a method thereof as well as a pH adjustor, in particular, relates to performing absorption/desorption to ions in the liquid using gels.
Mineral ions, including cations such as sodium, calcium, iron, copper ions and anions such as chloride, bromide, sulphate and carbonate ions, are considered as major solutes dissolved in water. In people's daily life and work, unwanted ions in e.g. aqueous solution usually need to be removed. The skilled person in the art ever assumes to stuff inorganic oxide gel in the brine chamber to reconstruct the electrodialysis apparatus such as disclosed in U.S. Pat. No. 3,847,788. When gel contacts with concetrated brine solution, syneresis takes place therefore electrolyte is exuded as overflow from gel, which eliminates the brine stream thereby lowering storage, pumping and piping requirements. However, such device still suffers from shortcomings such as complex construction, scaling problems, simutanelous generation of unwanted brine solution during deionization, which brings trouble in domestic use.
In view of the above problems, an ion absorption device for improving ion absorption speed and absorption efficiency is in urgent need in the art.
Therefore, the object of the present invention lies in solving at least one of said problems.
According to a first aspect of the present invention, it provides an ion absorption device, the device may comprise: an electrode pair, at least one electrode of the electrode pair is covered by ions-permeable gel with functional groups, the gel absorbs ions in a liquid when a voltage is applied on the electrode pair. Covering the electrode by ions-permeable gel with functional groups facilitates chelation of the cations such as sodium, calcium, iron, copper ions and the anions such as chloride, bromide, sulphate and carbonate ions in the liquid with the functional groups in the gel, thereby immobilizing these ions in the gel so as to improve absorption efficiency. In addition, what is used in respective embodiments of the present invention is ions-permeable gel, such an ions-permeable gel is inflatable in the solution, which on the one hand absorbs water in the solution and on the other hand absorbs the unwanted ions in the solution firmly. Different from the inorganic oxide gel used in e.g. U.S. Pat. No. 3,847,788, the gel used here will not exude the electrolyte even when a high concentration of salts is absorbed, which inhibits the simultaneous generation of unwanted brine solution.
In one embodiment of the present invention, the gel used therein may comprise natural polymers or synthetic polymers.
In another embodiment of the present invention, wherein the natural polymers may comprise: agarose, methylcellulose and hyaluronan; the synthetic polymers may comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers.
In a further embodiment of the present invention, the ion absorption device may further comprise: conductive materials between at least one electrode of the electrode pair and the gel, the conductive materials include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth. The conductive materials between at least one electrode and the gel facilitate the gel to cover the electrode better so as to enhance the binding force between them.
According to a second aspect of the present invention, it provides a pH adjustor comprising said ion absorption device. One electrode of the electrode pair is covered by the gel, and the gel absorbs H+ or OH− ions in a liquid when a voltage is applied on the electrode pair. Acidic water or alkaline water with different pH values can be generated based on user requirement by using the pH adjustor of the present invention.
According to a third aspect of the present invention, it provides an ion desorption device, which may comprise: an electrode pair, at least one electrode of the electrode pair is covered by ions-permeable gel with functional groups, the gel desorbs ions absorbed in the gel into a liquid when a reverse voltage is applied on the electrode pair. In the case of applying the reverse voltage, the repulsive force generated by the ions chelated together with the functional groups under the electric force is greater than the binding force with the functional groups, therefore, those ions bonded together with the functional groups will leave the gel successively and get into the solution. Thus, it is benefit for recycle use of the gel on the one hand, and acquisition of solution with desired ion content on the other hand.
In one embodiment of the present invention, the gel used therein may comprise natural polymers or synthetic polymers.
In another embodiment of the present invention, wherein the natural polymers may comprise: agarose, methylcellulose and hyaluronan; the synthetic polymers may comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers.
In a further embodiment of the present invention, the ion desorption device may further comprise: conductive materials between at least one electrode of the electrode pair and the gel, the conductive materials include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth. The conductive materials between at least one electrode and the gel facilitates the gel to cover the electrode better so as to enhance the binding force between them.
According to the fourth aspect of the present invention, it provides an ion absorption method, which may comprising the steps of: applying a voltage on an electrode pair, wherein at least one electrode of the electrode pair is covered by ions-permeable gel with functional groups, such that the gel absorbs ions in the liquid.
In one embodiment of the present invention, the gel used therein may comprise natural polymers or synthetic polymers.
In a further embodiment of the present invention, it may further comprise: conductive materials between at least one electrode of the electrode pair and the gel, the conductive materials include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth.
According to the fifth aspect of the present invention, it provides an ion desorption method, comprising: applying a reverse voltage on an electrode pair, wherein at least one electrode of the electrode pair is covered by ions-permeable gel with functional groups, so as to desorb ions absorbed in the gel into a liquid.
In one embodiment of the present invention, the gel used therein may comprise natural polymers or synthetic polymers.
In a further embodiment of the present invention, it may further comprise: conductive materials between at least one electrode of the electrode pair and the gel, the conductive materials may include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth.
The above and other features of the present invention will become more obvious through detailed explanation of embodiments shown in the drawings, in which the same or similar reference signs represent the same or similar components, wherein:
The present invention will be described hereinafter in detail with reference to the drawings of the present invention and the schematic embodiments thereof.
Firstly, referring to
In
The ions-permeable gel 16a or 16b (which will be mentioned later) with functional groups used in respective embodiments of the present invention is substantially a cross-linked system exhibiting no flow when in the steady-state. These gels are mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within the liquid.
Such ions-permeable gels 16a with functional groups can be used for ion absorption for the following reasons: 1) Over 90% of the total weight of gel is water, which has high permeability, and ions can get into the gel by free diffusion or under electric force. 2) The three-dimensional cross-linked network limits the mobility of the absorbed ions, preventing them from leaking out. 3) The active groups contained in gel such as hydroxyl groups, amino groups and carboxyl groups, which depend on the gel ingredients, can bind with ions by hydrogen bonding interaction or electrostatic interaction. Therefore, ions absorbed by gel can be further stabilized.
The gel 16a used in respective embodiments of the present invention may comprise natural polymers or synthetic polymers. The natural polymers comprise: agarose, methylcellulose and hyaluronan; the synthetic polymers comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers.
Preferably, the ion absorption device comprises conductive materials 24 between at least one electrode of the electrode pair 12, 14 and the gel 16a, the conductive materials 24 include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth, as schematically shown in
In order to understand the ion absorption device of the present invention better, schematic description will be made below through several embodiments.
The first electrode 12 of the electrode pair 12, 14 in
Namely, hydroxyl groups are contained in the chemical formula of the agarose gel. In the case of applying a voltage on the first electrode 12 and the second electrode 14, the Ca2+ in the water moves towards the first electrode 12 which serves as the cathode during the absorption, and gets into the gel. Since the hydroxyl groups in the agarose gel chelated the Ca2+, the Ca2+ is immobilized in the gel. Meanwhile, the water is deoxidized at the cathode surface, i.e., the following reaction occurs: 2H2O+2e=H2+2OH−, thereby, H2 and OH− are generated on the cathode surface. Part of the Ca2+ that get into the agarose gel chelated with the hydroxyl groups, while the other part of the Ca2+ continuously move towards the cathode in the agarose gel, the OH− ion as an ion with opposite polarity from Ca2+ generates closely bond Ca(OH)2 by maintaining neutral electricity, i.e., the OH− ion reacting with Ca2+, so as to stabilize the Ca ions in the gel further. The Ca2+ ions in the water are removed through said absorption of Ca2+ ions.
The skilled person in the art should understand that a corresponding ions-permeable gel 16a with functional groups can be used for a different ion absorption. For example, the methylcellulose, the methyl methacrylate, the methacrylic acid, the polyacrylamide and the methyl allyl sulfonate gel, acrylate polymers, copolymers have carboxyl functional groups, the hyaluronan and the polyvinyl alcohol have hydroxyl functional groups, and the polyurethane has amino functional groups, etc. The skilled person in the art should understand that the various natural polymer gels or synthetic polymer gels listed here are only demonstrative, which does not mean that the gels used in the respective embodiments of the present invention are limited to these. The hydrogel for absorbing heavy metal ions generally comprises various chelated functional groups, such as carboxyl (—COOH), amido (—NH2), hydroxyl (—OH), sulfonic group (—SO3) etc., so, if the hydrogel in general does not comprise functional groups for chelating heavy metal, chemical reaction should occur to itself to introduce such functional groups, or to introduce other substances to form copolymers so as to obtain such functional groups. This means that the skilled person in the art can make modification to the gel based on actual needs such that the gel covering the electrode can have one functional group such as amido, two functional groups such as amido and carboxyl, or three functional groups at the same time such as amido, carboxyl, and hydroxyl, or more other functional groups. This is not difficult for the skilled person in the art to realize, which will not be elaborated here.
The above embodiment 1 only schematically explains the process of absorbing the Ca2+ ions in water. During the process of carrying out the present invention, it may also need to absorb other ions e.g. cations such as sodium ions, iron ions, copper ions, or e.g. anions such as chloride ions, bromine ions, sulfate ions and carbonate ions. For example, in the case of absorbing the cations such as sodium ions, iron ions, copper ions in water, the surface of the first electrode 12 as the cathode should be covered by gel 16a. For example, in the case of absorbing the anions such as chloride ions, bromine ions, sulfate ions and carbonate ions in water, the surface of the second electrode 14 as the anode should be covered by gel 16a, i.e., using the ion absorption device as shown in FIG. 1B. For example, in the case of simultaneously absorbing the cations such as sodium ions, iron ions, copper ions and the anions such as chloride ions, bromine ions, sulfate ions and carbonate ions in water, both the surface of the first electrode 12 as the cathode and the surface of the second electrode 14 as the anode should be covered by gel 16a, i.e., using the ion absorption device as shown in
Alternatively, the ion absorption device as shown in
In this schematic embodiment, the fabricating process of agarose gel will be introduced schematically.
Generally, at the temperature of 90° C., agarose of 2 g can be dissolved in deionized water of 100 ml. When the agarose is completely dissolved, the agarose solution is poured into an electrode module containing electrodes, e.g. the electrode module containing the first electrode 12 and/or the electrode module containing the second electrode 14. Preferably, conductive material 24, such as carbon cloth, is applied between the electrode module and the agarose solution. The purpose of applying the carbon cloth lies in enhancing the bonding force between the agarose gel formed by the agarose solution and the electrode due to the concavo-convex shape of the surface of the carbon cloth. After cooling at room temperature for two hours, the agarose gel is formed on the surface of the first electrode 12 or the surface of the second electrode 14 or the surfaces of both. Subsequently, the electrode covered by the gel 16a is used for ion absorption.
The embodiment 2 takes the agarose gel formed on the surface of the electrode as example. According to the teaching of the present invention, the skilled person in the art needs to select different gel materials for absorbing different ions in the liquid 26a. After the corresponding gel materials are selected, it is not difficult to fabricate the corresponding gel on the corresponding electrode surface. It will not be elaborated in the present invention.
In order to explain the absorption speed and absorption efficiency of the present invention, the agarose gel fabricated in embodiment 2 will be used to cover the surfaces of the first electrode 12 and the second electrode 14 to perform the following experiment. The liquid 26a used in embodiment 3 is water containing Ca2+, CO32−, K+ and Cl− ions. The liquid 26a is input from the input 18 to a reaction chamber constituted by the first electrode 12 and the second electrode 14, and the agarose gel covering the first electrode 12 and the second electrode 14. DC voltage of 30V is applied on the first electrode 12 and the second electrode 14, standard titration is used to detect the content of ions in the liquid 26a. The detected data is shown in Table 1 below.
It is shown in Table 1 that the initial concentrations of the Ca2+, CO32−, K+ and Cl− ions are respectively 4.8 mM, 5.0 mM, 5 mM, 5 mM. After the voltage is applied for 10 minutes, the detected concentrations of the Ca2+, CO32−, K+ and Cl− ions are respectively 3.2 mM, 3.6 mM, 2.67 mM, 3.28 mM. After the voltage is applied for 30 minutes, the detected concentrations of the Ca2+, CO32−, K+ and Cl− ions are respectively 1.8 mM, 3.0 mM, 0.71 mM, 1.09 mM. After the voltage is applied for 60 minutes, the detected concentrations of the Ca2+, CO32−, K+ and Cl− ions are respectively 0.54 mM, 1.2 mM, 0.36 mM, 0.55 mM. It can be seen from the above experimental data that the longer time the voltage is applied, the lower the concentrations of the residual ions in the liquid 26a are, which means that more and more ions are absorbed on the agarose gel. Taking the Ca2+ for example, in the case of applying a DC voltage of 30V for 60 minutes, only 0.54 mM Ca2+ remains, which means that the Ca2+ substantially chelated with the hydroxyl groups through chelation, and as part of Ca2+ continuously move towards the cathode in the agarose gel, OH− ions generated at the cathode surface as counter ions of Ca2+ generate closely bonded Ca(OH)2 by maintaining neutral electricity, i.e., the OH− ions reacting with Ca2+, so as to further stabilize the Ca2+ ions in the water. These Ca(OH)2 and the chelated Ca2+ are all located on surface or inside of the agarose gel, or in a general term, on the agarose gel.
The above embodiments 1-3 of the present invention only take the agarose gel as example. It is not difficult for the skilled person in the art to understand that natural polymers or synthetic polymers may be used in the process of carrying out the present invention. The natural polymers may comprise: agarose, methylcellulose and hyaluronan etc. The synthetic polymers may comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers etc. The gels listed above are all ions-permeable gels with functional groups. In the case of applying a voltage, the ions e.g. cations such as sodium ions, iron ions, copper ions, or e.g. anions such as chloride ions, bromine ions, sulfate ions and carbonate ions in the liquid can be chelated together with the functional groups in the gel by covering the surface of the electrode with such gels. Thereby, these ions are quickly immobilized in the gel, and the absorption efficiency is improved.
Subsequently,
Of course, by means of the pH adjustor as shown in
It should be pointed out that the ion desorption process concerned in
For example, a reverse voltage is applied on the electrode pair 12, 14, wherein at least one electrode of the electrode pair 12, 14 is covered by an ions-permeable gel 16b with functional groups in order to desorb the ions absorbed in the gel 16b into the liquid 26b. For example, driven by electric force, the absorbed cations are released from the gel 16b and get into the liquid 26b. For example, in order to enable the absorbed cations such as sodium ions, iron ions, copper ions to be desorbed from the gel, a positive voltage can be applied to the electrode covered by the gel, in this way, since the polarity of the electrode and that of the cations absorbed in the gel are same, a repulsive effect is generated, thereby the cations absorbed in the gel are desorbed into the liquid 26b. The similar operation can be performed to the absorbed anions, i.e., applying a negative voltage to the electrode covered by the gel, so as to desorb the anions absorbed in the gel into the liquid 26b. This is easy for the skilled person in the art to understand.
For example, in the situation as shown in
The above is only a schematic explanation of
Similarly, the gel 16b used in the ion desorption device in the respective embodiments of the present invention may comprise natural polymers or synthetic polymers, wherein the natural polymers may comprise: agarose, methylcellulose and hyaluronan; the synthetic polymers may comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers.
Alternatively, the ion desorption device in the respective embodiments of the present invention may comprise conductive materials 24 between at least one electrode of the electrode pair 12, 14 and the gel 16b, the conductive materials 24 include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth.
Corresponding to the ion absorption device introduced above, the present invention may further provide an ion absorption method. The method may comprise the steps of: applying a voltage on an electrode pair 12, 14, wherein at least one electrode of the electrode pair 12, 14 is covered by ions-permeable gel 16a with functional groups, such that the gel 16a absorbs ions in the liquid 26a.
Corresponding to the ion desorption device introduced above, the present invention may further provide an ion desorption method. The method may comprise the steps of: applying a reverse voltage on an electrode pair 12, 14, wherein at least one electrode of the electrode pair 12, 14 is covered by ions-permeable gel 16b with functional groups, so as to desorb ions absorbed in the gel 16b into a liquid 26b.
Similarly, in the various ion absorption/desorption methods of the present invention, the gel used therein may comprise natural polymers or synthetic polymers, wherein the natural polymers may comprise: agarose, methylcellulose and hyaluronan; the synthetic polymers may comprise: polyacrylamide, polyvinyl alcohol, acrylate polymers and copolymers.
Alternatively, in the various ion absorption/desorption methods of the present invention, it may comprise conductive materials 24 between at least one electrode of the electrode pair 12, 14 and the gel 16a, the conductive materials 24 include at least one of: titanium, platinum, gold, rhodium, ruthenium; Ti—Ru alloy, graphite, active carbon, porous carbon paper or cloth.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/CN2012/001724 | Dec 2012 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2013/061124 | 12/19/2013 | WO | 00 |
