CN212142147U

CN212142147U - Separation device and liquid treatment apparatus

Info

Publication number: CN212142147U
Application number: CN202020325968.2U
Authority: CN
Inventors: 陈小平
Original assignee: Foshan Viomi Electrical Technology Co Ltd
Current assignee: Guangdong Lizi Technology Co Ltd
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-12-15
Anticipated expiration: 2030-03-16

Abstract

The electrochemical separation device comprises at least two electrochemical separation units connected in series, wherein each electrochemical separation unit comprises one or at least two electrochemical separation groups connected in parallel; in the desalination process, the total number of flow channels for desalination of one electrochemical separation unit is greater than the total number of flow channels for desalination of a subsequent electrochemical separation unit along the direction of the liquid flow. The electrochemical separation group is composed of a plurality of cation exchange membranes and anion exchange membranes which are alternately arranged. The electrochemical separation group can also be composed of at least one bipolar membrane. The utility model discloses a set up the different electrochemical separation unit of runner figure in electrochemical separation device for the liquid flow velocity in the runner increases, keeps or increases electrochemical separation unit's limiting current density, improves the desalination, reduce cost.

Description

Separation device and liquid treatment apparatus

Technical Field

The utility model relates to an electrochemical separation device and industrial or domestic water treatment equipment comprising the same.

Background

Electrochemical processes such as Electrodialysis (ED), frequent electrodialysis reversal (EDR), filling Electrodialysis (EDI), filling electrodialysis reversal (EDIR), and capacitive desalter (SCD) are widely used in separation processes such as desalination and desalination of solutions.

In an electrochemical separation process, taking electrodialysis as an example, when a material, also called a liquid to be treated (such as an aqueous solution, raw water or inlet water) flows in a thick chamber and a thin chamber, solute ions in the solution are directionally migrated under the action of a direct current electric field. When the working current is increased to a certain degree, ions in the solution can not be rapidly supplemented to the surface of the membrane, so that the ion concentration on the surface of the membrane approaches zero, and a large number of water molecules in the retention layer are ionized to generate H & lt + & gt and OH & lt- & gt ions to load charges, which is called polarization. The ionization density at this time also reaches a limit value, which is called the limiting current density. Once polarization occurs, the membrane surface is precipitated, the membrane resistance is obviously increased, the current efficiency and the desalination rate are reduced, the water production quality is reduced, and the service life of the electrodialysis membrane stack is shortened. Therefore, in order to prevent the occurrence of the polarization phenomenon, it should be ensured that the operating current of the electrodialysis membrane stack is not higher than the limit current value. However, because the working current is limited, a single electrodialysis unit is difficult to obtain high desalination rate, so the existing electrodialysis technology usually adopts a mode of connecting a plurality of membrane stacks in series to carry out desalination treatment, for example, to achieve about 85% desalination rate, an electrodialysis device and a system with three or more membrane stacks connected in series are often needed. The use of the multi-stage membrane stack increases the cost of the electrochemical separation apparatus, so that the electrochemical separation method has no cost advantage compared to the reverse osmosis membrane method.

How to further optimize the electrochemical separation device, ensure higher salt rejection rate and reduce the cost is a big problem still to be solved in the field.

SUMMERY OF THE UTILITY MODEL

An object of the present invention is to provide an electrochemical separation apparatus to improve the salt rejection and reduce the cost.

The above object of the present invention is achieved by the following technical means:

providing a method for removing ions in a liquid to be treated, which comprises at least two electrochemical separation units connected in series, wherein each electrochemical separation unit comprises one or at least two electrochemical separation groups connected in parallel;

in the desalination process, the total number of flow channels for desalination of one electrochemical separation unit is greater than the total number of flow channels for desalination of a subsequent electrochemical separation unit along the direction of the liquid flow.

Preferably, in the electrochemical separation device, the electrochemical separation group is provided with a cation exchange membrane and an anion exchange membrane, the electrochemical separation group is composed of a plurality of cation exchange membranes and anion exchange membranes which are alternately arranged, and the cation exchange membranes and the anion exchange membranes which are alternately arranged form corresponding fresh chamber channels and thick chamber channels;

in the desalination process, the total number of the dilute chamber channels of one electrochemical separation unit is equal to the total number of the desalted channels of the electrochemical separation unit along the direction of the liquid flow.

Preferably, in the above electrochemical separation apparatus, the membrane is a bipolar membrane, the electrochemical separation group is provided with at least one bipolar membrane, each bipolar membrane is composed of a cation exchange membrane and an anion exchange membrane which are attached together, and there is no flow channel between the cation exchange membrane and the anion exchange membrane which constitute the same bipolar membrane.

Preferably, in the electrochemical separation device, at least two of the electrochemical separation units are located between the same positive and negative electrodes.

In another preferred embodiment of the above electrochemical separation device, all the electrochemical separation units connected in series are located between the same positive and negative electrodes.

In another preferred embodiment, the electrochemical separation device comprises at least two electrochemical separation groups connected in parallel, and each electrochemical separation group is located between a pair of positive and negative electrodes.

In another preferred embodiment, the number of the flow channels of the electrochemical separation units connected in series decreases in the direction of the liquid flow.

In another preferred embodiment, the number of electrochemical separation units connected in series in the electrochemical separation apparatus is 2 to 20.

Preferably, the electrochemical separation apparatus is an electrodialysis apparatus, a frequent reverse electrodialysis apparatus, a packed reverse electrodialysis apparatus, a capacitive desalter, or a bipolar membrane electrodeionization apparatus.

A second object of the present invention is to provide an industrial or domestic water treatment apparatus, which employs the above electrochemical separation device.

The utility model discloses an electrochemical separation device, which comprises at least two electrochemical separation units connected in series, wherein each electrochemical separation unit comprises one or at least two electrochemical separation groups connected in parallel; in the desalination process, the total number of flow channels of one electrochemical separation unit is greater than the total number of flow channels of the next electrochemical separation unit in the direction of the liquid flow. The utility model discloses a set up the different electrochemical separation unit of runner figure in electrochemical separation device for the liquid flow velocity in the runner increases, keeps or increases electrochemical separation unit's limiting current density, improves the desalination, reduce cost.

Drawings

The accompanying drawings and the following detailed description are included to assist in understanding the features and advantages of the present invention, in which:

FIG. 1 is a schematic diagram of an electrochemical separation apparatus 100 according to one embodiment of the present invention, in which arrows indicate the flow direction of the liquid to be treated and the flow direction of the output liquid from the flow channel of the diluting chamber;

FIG. 2 is a schematic diagram of an electrochemical separation apparatus 200 according to one embodiment of the present invention, in which arrows indicate the flow direction of the liquid to be treated and the flow direction of the output liquid from the flow channel of the diluting chamber;

FIG. 3 is a schematic diagram of an electrochemical separation apparatus 300 according to an embodiment of the present invention, in which arrows indicate the flow direction of the liquid to be treated and the flow direction of the output liquid from the flow channel of the diluting chamber; and

fig. 4 is a schematic diagram of an electrochemical separation apparatus 400 according to an embodiment of the present invention, in which arrows indicate the flow direction of the liquid to be treated and the flow direction of the output liquid from the flow channel of the diluting chamber.

Fig. 5 is a schematic diagram of an electrochemical separation assembly 600 of a bipolar membrane electrodeionization device in accordance with an embodiment of the invention.

Fig. 6 is a schematic structural view of a bipolar membrane electrodeionization device according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of the bipolar membrane electrodeionization device of FIG. 6 in a desalination state.

Detailed Description

Unless clearly defined otherwise herein, the scientific and technical terms used have the meaning commonly understood by those of skill in the art to which this application pertains. As used in this application, the terms "comprising," "including," "having," or "containing" and similar referents to shall mean that the content of the listed items is within the scope of the listed items or equivalents thereof.

Approximating language, as used herein, is intended to modify a quantity, such that the invention is not limited to the specific quantity disclosed, but includes equivalent or equivalent means for performing the specified function and, if not limiting, further modifying the function of the described component. Accordingly, the use of "about," "left or right" and the like to modify a numerical value means that the invention is not limited to the precise numerical value recited. In some embodiments, the approximating language may correspond to the precision of an instrument for measuring the value. Numerical ranges in the present disclosure can be combined and/or interchanged, including all numerical sub-ranges subsumed therein unless expressly stated otherwise.

In the specification and claims, the singular and plural of all terms are not intended to be limiting unless the context clearly dictates otherwise. The use of "first," "second," and similar language in the description and claims of this application does not denote any order, quantity, or importance, but rather the intention is to distinguish one material from another, or embodiment.

Unless the context clearly dictates otherwise, the term "or", "or" does not mean exclusively, but means that at least one of the mentioned items (e.g. ingredients) is present, and includes the case where a combination of the mentioned items may be present.

Reference in the specification to "some embodiments" or the like means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the invention is included in at least one embodiment described in the specification, and may or may not be present in other embodiments. In addition, it is to be understood that the elements of the invention may be combined in any suitable manner.

Reference herein to "deionizing" a liquid to be treated is to remove ions from the liquid to be treated, including anions and cations in various valence states. In most cases, "deionization" has the same meaning as "desalination". In some cases, deionization is also referred to as demineralization.

The "liquid to be treated" referred to in the present specification means a liquid to be deionized or desalted, and in most cases, the liquid to be treated is an aqueous solution containing ions; in a few cases, the solvent of the liquid to be treated comprises a non-aqueous substance, such as glycerol. In most cases, the liquid to be treated is substantially free of organic matter or has been removed by other steps; in a few cases, the liquid to be treated still contains a certain amount of organic matter.

Reference to a "flow channel" in this specification means a channel through which a liquid flows. In the desalting condition, desalting may be performed in part of the channels as the light chamber channels, and salt concentration may also be performed in part of the channels as the thick chamber channels. In the desalination condition, all the flow channels may be used as desalination flow channels, and in the regeneration state, all the flow channels may be used as regeneration flow channels for collecting salt.

In the present specification, the "thin chamber flow channel" and the "thick chamber flow channel" are formed by alternately arranging cation exchange membranes and anion exchange membranes, and the thin chamber flow channel and the thick chamber flow channel are alternately arranged. In some embodiments, the dilute chamber flow channel and the concentrated chamber flow channel respectively contain a dilute chamber partition net and a concentrated chamber partition net, and the dilute chamber partition net and the concentrated chamber partition net are used for keeping a certain interval between the ion exchange membranes so as to form the flow channels. The spacer mesh may be a sheet of generally uniform thickness throughout and may include at least a portion of a mesh or mesh-like structure that allows liquid to pass therethrough to form a flow path for the liquid. The spacer mesh may be made of plastic or the like, suitable materials including, but not limited to, polypropylene (PP) and polyvinylidene fluoride (PVDF). In some embodiments, the thickness of the spacer mesh is approximately in the range of 0.5 to 2.0 millimeters.

References herein to "in series" and "in parallel" are intended to be made with respect to the direction of flow in the dilute chamber channel and the flow of the dilute chamber channel output. For example, if two electrochemical separation units are connected in series, the produced fluid from the dilute chamber channel of the previous electrochemical separation unit enters the dilute chamber channel of the next electrochemical separation unit. For another example, if two electrochemical separation groups are connected in parallel, it means that the dilute chamber channels of the two electrochemical separation groups receive the same feed liquid. The electrochemical separation cells in series are used to further remove ions from the liquid, while the electrochemical separation banks in parallel are used to increase the throughput of the device.

The "front" and "rear" in the "preceding electrochemical separation unit" and the "succeeding electrochemical separation unit" referred to in this specification are determined in accordance with the flow directions of the liquid to be treated and the dilute chamber liquid stream or the produced liquid, and may be referred to as "upstream" and "downstream", respectively.

The term "alternately arranged cation exchange membranes and anion exchange membranes" as used herein refers to an arrangement such as ACACACACAC, wherein a represents an anion exchange membrane and C represents a cation exchange membrane, but if one or more cation exchange membranes or anion exchange membranes are repeatedly arranged due to assembly errors or other reasons, such as the arrangement ACACACACCAC, the deionization function of the membrane stack is not affected, but only two adjacent channels are both light chamber channels or dense chamber channels, which should be regarded as a variation based on the embodiment of the present invention and still fall within the protection scope of the present invention. The situation that one or more cation exchange membranes or anion exchange membranes are repeatedly arranged and the anion exchange membranes and the cation exchange membranes are not strictly and alternately arranged is not avoided from the protection scope of the utility model.

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, A and C represent an anion exchange membrane and a cation exchange membrane, respectively, and + and-represent an anode and a cathode of an electrode, respectively.

The embodiment of the utility model provides a through set up the different electrochemical separation unit of light room runner figure in electrochemical separation device for the liquid flow velocity in the light room runner increases, keeps or increases electrochemical separation unit's limiting current density, improves the desalination, reduce cost. The embodiment of the utility model relates to an electrochemical separation device for get rid of the ion in the liquid of treating, including at least two electrochemical separation units that establish ties, every electrochemical separation unit includes one or at least two electrochemical separation groups that connect in parallel, and every electrochemical separation group fades the room runner and the dense room runner, and wherein, along the weak room liquid flow direction, the weak room runner total number of one of them electrochemical separation unit is greater than the weak room runner total number of an electrochemical separation unit that is located thereafter. The two electrochemical separation units with the difference in the total number of the flow channels of the fade chamber can be adjacent or not.

The utility model discloses an electrochemical separation device, which is used for removing ions in liquid to be treated and comprises at least two electrochemical separation units which are connected in series, wherein each electrochemical separation unit comprises one or at least two electrochemical separation groups which are connected in parallel; in the desalination process, the total number of flow channels for desalination of one electrochemical separation unit is greater than the total number of flow channels for desalination of a subsequent electrochemical separation unit along the direction of the liquid flow.

The membrane of the electrochemical separation group can be a cation exchange membrane or an anion exchange membrane, the electrochemical separation group is formed by a plurality of cation exchange membranes and anion exchange membranes which are alternately arranged, and the cation exchange membranes and the anion exchange membranes which are alternately arranged form a dilute chamber flow channel and a dense chamber flow channel which correspond to the electrochemical separation unit; in the desalting process, the total number of the flow channels of the dilute chamber of one electrochemical separation unit is the total number of the flow channels of the electrochemical separation unit along the direction of the liquid flow.

The membrane of the electrochemical separation group can also be a bipolar membrane, the electrochemical separation group is formed by at least one bipolar membrane, each bipolar membrane is formed by a cation exchange membrane and an anion exchange membrane which are attached together, and no flow channel is formed between the cation exchange membrane and the anion exchange membrane which form the same bipolar membrane. In the bipolar membrane electrodeionization device comprising the bipolar membrane, all the flow paths are desalted during desalting, and therefore, all the flow paths are desalted, and in a regeneration state, all the flow paths are used as regeneration flow paths.

Fig. 1 is a schematic structural diagram of an electrochemical separation apparatus 100 according to an embodiment of the present invention, which includes a pair of electrodes (negative electrode 101 and positive electrode 102) and three

electrochemical separation units

110, 120, 130 located between the electrodes, each electrochemical separation unit includes an electrochemical separation set, and the electrochemical separation set includes a plurality of cation exchange membranes and anion exchange membranes arranged alternately, and a plurality of fresh chamber channels and dense chamber channels formed by the cation exchange membranes and the anion exchange membranes. The smallest desalination unit consisting of one cation exchange membrane, one dilute chamber, one anion exchange membrane and one dense chamber is called "membrane pair". Each electrochemical separation unit may be designed in the number of membrane pairs according to desalination requirements, the number of membrane pairs shown in fig. 1 is only an example, and the number of membrane pairs used in an electrochemical separation apparatus generally used in practice is several tens or hundreds. Assuming that the number of the flow channels of the light chambers of the

electrochemical separation units

110, 120, 130 of the apparatus 100 is M1, M2 and M3, respectively, in some embodiments of the present invention, M1> M2> M3, i.e. the number of the flow channels of the light chambers of the three electrochemical separation units decreases sequentially; in other embodiments of the present invention, M1 ═ M2> M3 or M1> M2 ═ M3.

The three

electrochemical separation units

110, 120, 130 of the device 100 are located between the same pair of electrodes, and they may be separated by using ion exchange membranes to realize the change of the liquid flow direction. For example: the water inlet of the electrochemical separation unit 110 and the water outlet of the electrochemical separation unit 120 are in the same position, but the inverted membrane is closed at this position, so that the electrochemical separation unit 110 and the electrochemical separation unit 120 can be isolated; meanwhile, the water outlet of the electrochemical separation unit 110 and the water inlet of the electrochemical separation unit 120 are located at the same position, but the inverted membrane is open at this position, so that the effluent of the electrochemical separation unit 110 can enter the electrochemical separation unit 120 as the feed of the electrochemical separation unit 120.

In addition to disposing all of the electrochemical separation units in series between the same pair of electrodes, in certain other embodiments of the present invention, portions, e.g., two or more, of adjacent electrochemical separation units may be disposed between the same pair of electrodes. Such as electrochemical separation apparatus 200 shown in fig. 2. The device 200 comprises a first pair of electrodes (negative electrode 201 and positive electrode 202), a second pair of electrodes (positive electrode 203 and negative electrode 204), and three

electrochemical separation units

210, 220, 230, each comprising an electrochemical separation group, wherein the electrochemical separation unit 210 is located between the first pair of electrodes, the

electrochemical separation units

220 and 230 are located between the second pair of electrodes, and the

electrochemical separation units

220 and 230 share the second pair of electrodes. Assuming that the number of the light-chamber channels of the

electrochemical separation units

210, 220, 230 of the apparatus 200 is N1, N2 and N3, respectively, in some embodiments of the present invention, N1> N2> N3, i.e. the number of the light-chamber channels of the three electrochemical separation units decreases sequentially; in other embodiments of the present invention, N1 ═ N2> N3 or N1> N2 ═ N3. In the device 200, the electrode plates adjacent to the first pair of electrodes and the second pair of electrodes are the same type of electrodes (here, both positive electrodes), so that the number of cables can be reduced, and the system can be simplified.

In certain embodiments of the present invention, the different electrochemical separation units do not share electrodes, and the voltage of each electrochemical separation unit can be separately controlled, for example, as shown in the electrochemical separation apparatus 300 of fig. 3. The apparatus 300 comprises three pairs of electrodes and three

electrochemical separation units

310, 320, 330, and there is a one-to-one correspondence, i.e., the electrochemical separation unit 310 is located between the first pair of electrodes (negative electrode 311 and positive electrode 312); electrochemical separation cell 320 is positioned between a second pair of electrodes (negative electrode 321 and positive electrode 322); the electrochemical separation unit 330 is located between the third pair of electrodes (the negative electrode 331 and the positive electrode 332). Wherein each electrochemical separation unit comprises an electrochemical separation group, namely a plurality of cation exchange membranes and anion exchange membranes which are alternately arranged and are positioned between electrodes, and a plurality of dilute chamber flow channels and concentrated chamber flow channels which are formed by the cation exchange membranes and the anion exchange membranes. Assuming that the number of the flow channels of the light chambers of the

electrochemical separation units

310, 320, 330 of the apparatus 300 is O1, O2 and O3, respectively, in some embodiments of the present invention, O1> O2> O3, i.e. the number of the flow channels of the light chambers of the three electrochemical separation units decreases sequentially; in other embodiments of the present invention, O1 ═ O2> O3 or O1> O2 ═ O3.

In some embodiments of the present invention, at least one of the electrochemical separation units may include two or more electrochemical separation sets connected in parallel, and the number of the electrochemical separation sets included in different electrochemical separation units may be the same or different. For example, the electrochemical separation apparatus 400 shown in fig. 4 includes three electrochemical separation units, wherein a first electrochemical separation unit includes three

electrochemical separation groups

4101, 4102, 4103; the second electrochemical separation unit comprises two

electrochemical separation groups

4201, 4202; the third electrochemical separation unit includes one electrochemical separation group 4301. Each electrochemical separation group is located between a pair of positive and negative electrodes, and thus, the device 400 includes six pairs of electrodes. In the same electrochemical separation unit, the number of the flow channels of the fade chambers in each electrochemical separation group can be the same or different. The number of flow channels of the fade chambers of the first electrochemical separation unit is the sum of the number of flow channels of the fade chambers in the three

electrochemical separation groups

4101, 4102, 4103, and similarly, the number of flow channels of the fade chambers of the second electrochemical separation unit is the sum of the number of flow channels of the fade chambers in the two

electrochemical separation groups

4201, 4202. Assuming that the number of the flow channels of the light chambers of the three electrochemical separation units is P1, P2 and P3, in some embodiments of the present invention, P1> P2> P3, that is, the number of the flow channels of the light chambers of the three electrochemical separation units decreases in sequence; in other embodiments of the present invention, P1 ═ P2> P3 or P1> P2 ═ P3.

Although the electrochemical separation devices shown in fig. 1, fig. 2, fig. 3 and fig. 4 all include three electrochemical separation units, in the embodiment of the present invention, the number of electrochemical separation units is not limited to three, and generally, the electrochemical separation device of the present invention includes 2 to 20 electrochemical separation units connected in series.

The utility model discloses electrochemical separation device can be electrodialysis, frequent reverse electrode electrodialysis, filled reverse electrode electrodialysis, electric capacity desalination ware or bipolar membrane electrodeionization device. Reference herein to "electrodialysis" is to conventional electrodialysis, i.e. no ion exchange material is filled between the membranes. Reference herein to "packed electrodialysis", also known as Electrodeionization (EDI) or continuous electrodeionization (CDI), relies on electrolyzed water to regenerate the ion exchange resin in the dilute cells.

An embodiment of the electrochemical separation device of the present invention may be a structural form of a bipolar membrane electrodeionization device. The bipolar membrane electrodeionization device comprises at least two electrochemical separation units connected in series, each electrochemical separation unit comprises one or at least two electrochemical separation groups connected in parallel, and the total number of flow channels of one electrochemical separation unit is larger than that of the next electrochemical separation unit along the flow direction in the desalination process.

In the bipolar membrane electrodeionization device, the membrane is a bipolar membrane, the electrochemical separation group is composed of at least one bipolar membrane, each bipolar membrane is composed of a cation exchange membrane and an anion exchange membrane which are attached together, no flow channel exists between the cation exchange membrane and the anion exchange membrane which form the same bipolar membrane, and the number of the flow channels in the same electrochemical separation unit is the number of the flow channels for desalination in a desalination state.

In one embodiment, the electrochemical separation unit of the bipolar membrane electrodeionization device can be formed by one or more electrochemical separation groups in parallel, and the electrochemical separation groups can be formed by one or more bipolar membranes. The number of bipolar membranes constituting electrochemical separation assembly 600 may be selected as desired, and is typically from 1 to 50, or may be set to a greater number as desired.

Taking the electrochemical separation group 600 shown in fig. 5 as an example, three bipolar membranes 6300 are adopted, and each bipolar membrane 6300 is composed of a cation exchange membrane 6310 and an anion exchange membrane 6320 which are bonded together.

One or two electrochemical separation groups are connected in parallel to form an electrochemical separation unit, and the number of the electrochemical separation groups forming each electrochemical separation unit can be one, two, three or other number; and different electrochemical separation units are connected in series to form the integrated electrochemical separation device, and the number of the electrochemical separation units forming the integrated electrochemical separation device can be one, two, three or other numbers. The technical proposal of the utility model is satisfied if the requirement that the total number of the flow channels of one electrochemical separation unit is larger than that of the flow channels of the next electrochemical separation unit along the liquid flow direction in the desalting process is satisfied.

Fig. 6 is a schematic configuration diagram of a bipolar membrane electrodeionization apparatus having two electrochemical separation units connected in series between a pair of electrodes, one electrochemical separation unit being composed of an electrochemical separation group 610 and the other electrochemical separation unit being composed of an electrochemical separation group 620. The electrochemical separation group 610 is composed of three bipolar membranes, and the electrochemical separation group 620 is composed of two bipolar membranes.

One flow method of the bipolar membrane electrodeionization device: in the desalting process, enabling the liquid to be treated to flow through the flow channel of the first electrochemical separation unit, and enabling the flow channel output liquid of the previous electrochemical separation unit to flow through the diluting chamber flow channel of the next electrochemical separation unit;

in the regeneration process, enabling the flow passage output liquid of the previous electrochemical separation unit to flow through the flow passage of the next electrochemical separation unit along the same liquid flow direction;

and collecting the treated liquid from the outlet of the flow channel of the last electrochemical separation unit.

The bipolar membrane electrodeionization device can also adopt another liquid flow mode: in the desalting process, enabling the liquid to be treated to flow through the flow channel of the first electrochemical separation unit, and enabling the flow channel output liquid of the previous electrochemical separation unit to flow through the flow channel of the next electrochemical separation unit;

during regeneration, in the opposite flow direction, the flow channel output liquid of the next electrochemical separation unit flows through the flow channel of the previous electrochemical separation unit;

and collecting the treated liquid from the outlet of the flow channel of the first electrochemical separation cell.

The embodiment of the utility model also comprises an industrial or domestic water treatment equipment.

The operation of the bipolar membrane electrodeionization device will be described by taking the bipolar membrane electrodeionization device of FIG. 6 as an example. Bipolar membrane electrodeionization apparatus in the desalination process, the cation exchange membrane of the bipolar membrane faces the positive electrode, and the raw water is desalinated in the flow channel formed between the two bipolar membranes. Anions in the raw water, e.g. Cl^-Move towards the positive electrode to replace OH in the right anion exchange membrane^-，OH^-Entering a flow channel; with cations such as Na in the raw water⁺Moving toward the negative electrode to replace H in the cation exchange membrane of the left bipolar membrane⁺Ion, H⁺Entering a flow channel; h⁺And OH^-Neutralization reaction occurs in the flow channel to generate water, so that the salt in the raw water is removed, and pure water flows out from the tail end of the flow channel.

Accordingly, as shown in fig. 7, raw water first enters an upstream electrochemical separation unit formed by an electrochemical separation group 610, and anions such as Cl in the raw water are in a flow channel of the electrochemical separation group 610^-Move towards the positive electrode to replace OH in the right anion exchange membrane^-，OH^-Entering a flow channel; with cations such as Na in the raw water⁺Moving toward the negative electrode to replace H in the cation exchange membrane of the left bipolar membrane⁺Ion, H⁺Entering a flow channel; h⁺And OH^-The neutralization reaction occurs in the flow channel to generate water, so that the salt in the raw water is removed, and the pure water flows out from the tail end of the flow channel of the electrochemical separation group 610 and then enters the downstream electrochemical separation group 620 to form downstream electrochemical separationDesalting was continued in the chemical separation unit. In the flow channels of the electrochemical separation group 620, desalting treatment is similarly performed, and the obtained desalted pure water flows out from the ends of the flow channels of the electrochemical separation group 620.

When desalination is carried out for a period of time, reverse-pole regeneration is required to release ions in the water adsorbed on the bipolar membrane. At this time, the interface layers of the cationic and anionic membranes of the bipolar membrane generate OH under the electric field^-And H⁺Ionic, cationic inside the cationic membrane of the bipolar membrane, e.g. Na⁺Quilt H⁺The ions are displaced and move to the negative electrode, and anions such as Cl in the anionic membrane of the bipolar membrane^-Is covered with OH^-The displacement toward the positive electrode, Na⁺、Cl^-Entering the flow passage to complete regeneration.

Examples of uses of the "industrial water treatment facility" referred to herein include, but are not limited to, industrial sewage treatment, municipal sewage treatment, seawater desalination, brine treatment, river and lake water treatment, cheese whey demineralization, and the like. The industrial water treatment apparatus includes, in addition to the electrochemical separation device of an embodiment of the present invention, one or more of, for example, a flocculation and/or coagulation unit, an advanced oxidation unit, an adsorption unit, an electrolysis unit, a membrane separation unit (including one or more of microfiltration, ultrafiltration, nanofiltration and reverse osmosis).

The utility model discloses domestic water treatment facilities, except the utility model discloses the electrochemical separation device of embodiment generally still includes for example the ultrafiltration, receive and strain, activated carbon adsorption unit, one or more in the ultraviolet sterilization unit.

Experimental examples

Some experimental examples of the present invention are provided below. The following experimental examples may provide reference for a person having ordinary skill in the art to practice the present invention. These examples do not limit the scope of the claims.

In a comparative experiment, a conventional electrochemical separation apparatus having the same number of fresh water flow channels and an electrochemical separation apparatus employing a gradual decrease in the number of fresh water flow channels as shown in FIG. 1 of the present invention were used for the solution desalting treatment, respectively, and the size and model of the ion exchange membrane and the size and model of the mesh were completely the same for both of the two electrochemical separation apparatuses. In this experiment, titanium electrodes coated with ruthenium yttrium were used, respectively treated with an aqueous solution of sodium chloride (NaCl) having a conductivity of 2000uS/cm and a flow rate of 2l/min at the inlet, and a constant voltage mode was used in the experiment, in which the voltage was set to direct current 36V. Under the same operation conditions, the salt rejection of the conventional electrochemical separation device having the same number of fresh water flow channels was 85%, whereas the salt rejection of the electrochemical separation device using the gradually decreasing number of fresh water flow channels was 92%, and the salt rejection increased by about 8%.

In a comparative experiment, a conventional electrochemical separation apparatus having the same number of fresh water flow channels and a bipolar membrane electrodeionization apparatus using the same type of the present invention as shown in FIG. 6 were used for the solution desalting treatment, respectively. In this experiment, titanium electrodes coated with ruthenium yttrium were used, and separately treated with an aqueous solution of sodium chloride (NaCl) having a conductivity of 2000uS/cm at a flow rate of 1L/min at the inlet, and a constant voltage mode was used in the experiment in which the voltage was set to direct current 40V. Under the same operating conditions, the desalination rate of the conventional electrochemical separation apparatus having the same number of fresh water flow channels was 75%, whereas the desalination rate of the bipolar membrane electrodeionization apparatus shown in FIG. 7 was 86%, which was increased by about 11%.

The above electrochemical separation device and water treatment apparatus are only preferred embodiments of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principles of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.

Claims

1. An electrochemical separation device for removing ions from a liquid to be treated, comprising: comprises at least two electrochemical separation units connected in series, wherein each electrochemical separation unit comprises one or at least two electrochemical separation groups connected in parallel;

2. The electrochemical separation device of claim 1, wherein: the electrochemical separation group consists of a plurality of cation exchange membranes and anion exchange membranes which are alternately arranged, and the alternately arranged cation exchange membranes and anion exchange membranes form corresponding dilute chamber runners and dense chamber runners;

3. The electrochemical separation device of claim 1, wherein: the electrochemical separation group is provided with at least one bipolar membrane, each bipolar membrane is composed of a cation exchange membrane and an anion exchange membrane which are attached together, and no flow channel is arranged between the cation exchange membrane and the anion exchange membrane which form the same bipolar membrane.

4. The electrochemical separation apparatus of claim 1, wherein: at least two of the electrochemical separation units are positioned between the same positive and negative electrodes.

5. The electrochemical separation apparatus of claim 4, wherein: all the electrochemical separation units connected in series are positioned between the same positive and negative electrodes.

6. The electrochemical separation apparatus of claim 1, wherein: at least one electrochemical separation unit comprises at least two electrochemical separation groups connected in parallel, and each electrochemical separation group is positioned between a positive electrode and a negative electrode.

7. The electrochemical separation apparatus of claim 1, wherein: along the direction of liquid flow, the number of the flow channels of the electrochemical separation units connected in series is gradually reduced.

8. The electrochemical separation apparatus of claim 1, wherein: the number of electrochemical separation units in series is from 2 to 20.

9. The electrochemical separation apparatus of claim 1, wherein: is an electrodialysis device, a frequent reverse electrode electrodialysis device, a filling type reverse electrode electrodialysis device, a capacitance desalter or a bipolar membrane electrodeionization device.

10. An industrial or domestic water treatment apparatus, characterized by: an electrochemical separation apparatus comprising a separator according to any one of claims 1 to 9.