JP2016140466A - Dialysate solution regeneration method, dialysate solution regeneration device, and preliminarily adjusted cation exchange resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dialysate solution regeneration method, a dialysate solution regeneration device, and a preliminarily adjusted cation exchange resin that, on the assumption that a used dialysate solution is caused to come into contact with a cation exchange resin to cause urea contained in the used dialysate solution to adhere to the cation exchange resin, can adjust pH of the dialysate solution from which urea is removed to an appropriate range.SOLUTION: A dialysate solution regeneration method includes a urea removal process in which a used dialysate solution 22 used for artificial dialysis is caused to come into contact with a cation exchange resin 80 so as to cause urea contained in the used dialysate solution 22 to adhere to the cation exchange resin 80, and a pH adjusting process in which the used dialysate solution 22 is caused to come into contact with an anion exchange resin 90 to adjust pH of the used dialysate solution 22. A dialysate solution regeneration device 100 includes a urea removal tank 130 in which the used dialysate solution 22 is caused to come into contact with the cation exchange resin 80, and a pH adjusting tank 140 in which the used dialysate solution 22 is caused to come into contact with the anion exchange resin 90.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dialysate regeneration method, a dialysate regeneration apparatus, and a preconditioned cation exchange resin.

  The dialysate used for artificial dialysis (hereinafter also referred to as used dialysate) includes waste products such as urea transferred from the blood of the subject. Therefore, the dialysate has generally been discarded after a single use.

  However, in general artificial dialysis, depending on body weight and the like, it is necessary to use a large amount of dialysate of about 90 L to about 150 L in a single (daily) treatment. For this reason, there is a demand for reuse of the used dialysate, and some proposals have been made on a technique for regenerating used dialysate.

  For example, Patent Document 1 listed below discloses a technique for regenerating a used dialysate by decomposing urea contained in the used dialysate into ammonia by a urea-degrading enzyme such as urease and removing the ammonia (hereinafter, conventionally referred to as conventional dialysate). (Also referred to as Invention 1).

Patent Document 2 below discloses a wearable artificial kidney dialysis system (hereinafter also referred to as Conventional Invention 2) having a urea removal layer.
Conventional invention 2 discloses a technique for removing urea contained in a peritoneal dialysis solution. Specifically, it is described in paragraph [0012] of the same literature that a urea removing layer is provided and a composition that allows urea to pass through but repels cations is included. The paragraph [0034] in the same document lists a plurality of modes that the conventional invention 2 can take.

  Specifically, in the first aspect of the conventional invention 2, an ion exchange resin such as a strongly acidic cation exchange resin and a basic anion exchange resin or a dual characteristic resin for removing urea is disposed around the hollow fiber. A urea removal layer. The said hollow fiber is a structure which repels a cation, does not let a cation pass, and lets urea pass selectively. Therefore, in the first aspect, a part of the urea from the used dialysate circulating in the hollow fiber passes through the hollow fiber and is adsorbed on the ion exchange resin disposed around.

The second aspect of Conventional Invention 2 includes a urea removal layer composed of urease, which is a urea-degrading enzyme, and an ion exchange resin or an inorganic adsorbent. That is, in the second aspect, urea is removed from the used dialysate by decomposing urea contained in the used dialysate with urease and adsorbing the ammonium produced thereby with an ion exchange resin.
Patent Document 3 will be described later.

JP-T-2014-530634 Special table 2010-536473 gazette Japanese Patent Laid-Open No. 2001-199918

Conventional inventions 1 and 2 described above have the following problems.
That is, in the second aspect of Conventional Invention 1 and Conventional Invention 2, both urea is decomposed into ammonia with urease, the ammonia is captured with an ammonia scavenger such as an ion exchange resin, and as a result, used dialysate This is a technique for reducing the content of urea contained therein. However, in such a technique, ammonia may remain in the regenerated dialysate unless ammonia as a decomposition product is completely captured. It is a well-known knowledge that ammonia is essentially unnecessary for the human body. Therefore, when there is a possibility that uncaptured ammonia may remain in the dialysate treated by the above technique, there is a problem in reusing the dialysate.

  On the other hand, the first aspect of Conventional Invention 2 is a technique for removing urea by directly adsorbing it to an ion exchange resin without decomposing it, so there is no possibility that ammonia derived from urea remains in the dialysate. However, in the first aspect of the conventional invention 2, the used dialysate is circulated through the hollow fiber that can selectively pass urea without passing the cation, and the urea that has passed from the inside of the hollow fiber to the outside is removed by adsorption. Technology. Therefore, since urea that has not passed through the hollow fiber remains in the dialysate, a high urea removal rate cannot be expected.

  Therefore, the present inventor does not decompose urea contained in the used dialysate into ammonia, and allows the urea to be removed in a high yield, in order to contact the used dialysate directly with the ion exchange resin. It was investigated. Specifically, a technique was examined in which the used dialysis solution was brought into contact with a cation exchange resin and urea contained in the used dialysis solution was adhered to the cation exchange resin. From this examination, it was found that urea can be removed from the used dialysate with a high removal rate. However, it has been found that the method of directly contacting the used dialysate with the cation exchange resin and attaching urea to the urea has the following problems.

  That is, the dialysate, which is a treated solution obtained after contacting the used dialysis solution with the cation exchange resin and attaching urea to the cation exchange resin, exhibits an acidic pH. There was a problem that it was difficult to reuse. It is conceivable to adjust the dialysate to the desired pH using an appropriate neutralizer, but adjusting the dialysate that is largely acid-biased with only a large amount of neutralizer will generate a large amount of impurities. Then, there was a risk of mixing into the dialysate.

  The present invention has been made in view of the above problems. That is, the present invention allows the pH of the dialysate to be moderately adjusted while bringing the spent dialysate into contact with the cation exchange resin to remove the urea contained in the used dialysate from the cation exchange resin. Provided are a dialysate regeneration method, a dialysate regeneration apparatus, and a preconditioned cation exchange resin that can be adjusted well within a range.

  The dialysate regeneration method of the present invention comprises a urea removal step in which a used dialysate used for artificial dialysis is brought into contact with a cation exchange resin, and urea contained in the used dialysate is adhered to the cation exchange resin; And a pH adjustment step of adjusting the pH of the used dialysate by bringing the used dialysate into contact with an anion exchange resin.

  Moreover, the dialysate regeneration apparatus of this invention has a urea removal tank which makes a used dialysate contact a cation exchange resin, and a pH adjustment tank which makes the said used dialysate contact an anion exchange resin.

  The pre-adjusted cation exchange resin of the present invention is a cation exchange resin used in the dialysate regeneration method of the present invention, and adheres urea contained in the urea-containing liquid by contacting with the urea-containing liquid, It has been subjected to a preliminary adjustment in which urea is removed by contact with a chemical solution.

According to the artificial dialysate regeneration method and the artificial dialysate regeneration apparatus of the present invention, it is possible to satisfactorily adjust the pH of the regenerative dialysate to an appropriate range while removing urea from the used dialysate with high efficiency.
Moreover, the artificial dialysate regeneration method can be favorably repeated by using the preconditioned cation exchange resin of the present invention.

It is a conceptual diagram of the dialysate reproduction | regeneration apparatus concerning 1st embodiment of this invention. It is a conceptual diagram of the dialysate reproduction | regeneration apparatus concerning 2nd embodiment of this invention. FIG. 3A is an experimental flow (first test) for repeating the urea removal step three times in the embodiment of the present invention including the cation exchange resin regeneration step, and FIG. 3B is a book including the cation exchange resin regeneration step. In the aspect of invention, it is an experimental flow (2nd test) for repeating a urea removal process twice. It is a general view of the test apparatus for implementing a 1st test and a 2nd test.

The dialysate regeneration method of the present invention (hereinafter also referred to as the method of the present invention), the dialysate regeneration device (hereinafter also referred to as the device of the present invention), and a preconditioned cation exchange resin will be described below. In all the drawings used for the description of the present invention, the same components are denoted by the same reference numerals, and redundant description will be appropriately omitted.
The various components of the dialysate regenerator of the present invention do not have to be individually independent, but a plurality of components are formed as a single member, and a single component is formed of a plurality of members. That a certain component is a part of another component, a part of a certain component overlaps a part of another component, and the like.
When the dialysate regeneration method of the present invention is carried out, the order of the plurality of steps can be changed within a range that does not hinder the contents, and some or all of the execution timings of the plurality of steps overlap each other. May be.

  In the present invention, artificial dialysis is a hemodialysis therapy that artificially replaces the function of the kidney, and means a method of removing waste products such as urea contained in the blood of a subject via a dialysate. The dialysate may contain an electrolyte or the like as appropriate to replenish deficient substances in the blood. In the present invention, the used dialysate means a liquid used in artificial dialysis and containing at least urea. In the present invention, regenerating the dialysate means that at least urea is removed from the used dialysate, and the pH is adjusted again to a range that can be used as the dialysate. Here, the pH that can be used as the dialysate includes both the pH that can be used again as the dialysate and the pH that can be easily adjusted to the pH that can be used as the dialysate.

The dialysate regeneration method of the present invention has a urea removal step and a pH adjustment step.
In the urea removal step, the used dialysis solution used for the artificial dialysis is brought into contact with the cation exchange resin, and the urea contained in the used dialysis solution is adhered to the cation exchange resin. In the pH adjustment step, the used dialysate is brought into contact with the anion exchange resin to adjust the pH of the used dialysate.

  According to the method of the present invention, the pH of the used dialysate from which urea has been removed is adjusted to a preferable range as compared with the case where the urea is simply removed by contacting the used dialysate with a cation exchange resin. Is possible. That is, in the present invention, the spent dialysate tends to be biased toward the acidic side by contacting with the cation exchange resin, while it tends to be biased toward the basic side by contacting with the anion exchange resin. The present invention utilizes this tendency to adjust the pH of the used dialysate by bringing the used dialysate into contact with the cation exchange resin and the anion exchange resin in order or simultaneously.

  Details of the urea removal step will be described below. In the urea removal step in the present invention, the used dialysate used for artificial dialysis is brought into contact with the cation exchange resin, and urea contained in the used dialysate is adhered to the cation exchange resin.

  The cation exchange resin used in the present invention is a resin capable of adhering urea contained in the used dialysate by contacting with the used dialysate, and is generally understood as a cation exchange resin. It is suitably selected from resins. In the present invention, the cation exchange resin includes a strong acid cation exchange resin and a weak acid cation exchange resin. From the viewpoint of increasing the urea removal rate, the method of the present invention preferably uses a strongly acidic cation exchange resin.

  In the method of the present invention, the spent dialysate and the cation exchange resin are brought into direct contact in the urea removal step. As a result, the method of the present invention can easily attach urea contained in the used dialysate to the cation exchange resin, and can remove urea from the used dialysate with high efficiency. Examples of the method of directly contacting the used dialysate and the cation exchange resin include, but are not limited to, a column method or a batch method. Here, the column system is a system in which a used dialysate is dropped onto a column filled with a predetermined cation exchange resin. The batch method is a method in which the ion exchange resin and the treatment liquid are stirred and mixed.

  Urea adhering to a cation exchange resin broadly includes the temporary increase of urea around the cation exchange resin, for example, ion exchange between cation exchange resin and urea, or cation exchange resin and Includes hydrogen bonding with urea. The above ion exchange means that a cation is released from a cation exchange resin (particularly a functional group having an ion exchange ability of a cation exchange resin), and urea contained in a used dialysate is ionized to form a cation. It means ion exchange taken into the exchange resin. The hydrogen bond means that urea is electrostatically intermolecularly bonded to a cation exchange resin (particularly a functional group having an ion exchange ability of the ion exchange resin).

  Next, the details of the pH adjustment step will be described. The pH adjustment step in the present invention adjusts the pH of the used dialysate by bringing the used dialysate into contact with an anion exchange resin.

  The anion exchange resin used in the present invention is a resin capable of releasing anions from a functional group having an ion exchange ability of the anion exchange resin. The reason why the pH of the used dialysate can be adjusted in the pH adjustment step is not clear, but the anion released from the anion exchange resin acts on the used dialysate, so that the pH of the used dialysate is reduced. Presumed to be adjusted. The anion exchange resin includes a strong basic anion exchange resin and a weak basic anion exchange resin. In the pH adjustment step, the pH of the used dialysate can be adjusted to a desired range by adjusting the contact condition between the anion exchange resin and the used dialysate. Details of the contact condition will be described later.

  In the pH adjustment step, the used dialysate and the anion exchange resin may be brought into contact directly or indirectly within a range in which the pH of the used dialysate can be adjusted. Examples of the method for directly contacting the used dialysate and the anion exchange resin include a column method or a batch method as described above, but are not limited thereto. As a method for directly contacting the used dialysate and the anion exchange resin, for example, the used anion exchange resin and the anion exchange resin are used through a membrane capable of passing a cation (cation) and an anion (anion). A method of confronting the dialysate can be exemplified. In this embodiment, the pH of the used dialysate can be adjusted by exchanging the anion contained on the anion exchange resin side and the cation contained on the used dialysate side through the membrane. The membrane may be in various forms such as a film or a tube such as a hollow fiber or a hollow fiber.

  Specifically, the adjustment of the pH in the pH adjustment step includes adjusting the pH of the used dialysate from the acidic side to neutral or alkaline, and adjusting from the alkaline side to the acidic side. The dialysate used for the artificial dialysis is generally adjusted to a pH of about 7 to 7.5 although it depends on the dialysis method and the condition of the subject. Therefore, the pH of the regenerated dialysate obtained by performing the urea removal step and the pH adjustment step should be pH 7 or near pH 7, or a pH within a range that can be easily adjusted to near pH 7 or pH 7. preferable. Here, pH 7 or near pH 7 refers to, for example, a range from pH 6 to less than pH 11, preferably from pH 7 to pH 9, and more preferably from pH 7 to pH 9. In other words, the regenerated dialysis solution obtained by the method of the present invention may be reused for artificial dialysis without further adjustment of pH, or in a small amount to be reused for artificial dialysis. It may be one that requires fine adjustment to a desired pH by using a compatibilizer or the like. However, the above description does not limit the pH adjustment step in the method of the present invention and the pH value of the regenerated dialysate obtained by carrying out the method of the present invention.

  In the pH adjustment step, the pH of the used dialysate can be adjusted to a desired range by adjusting the contact condition between the anion exchange resin and the used dialysate. The contact conditions can be adjusted by appropriately changing the flow rate of the used dialysate, the amount or type of the anion exchange resin used in the pH adjustment step in which the column method described above is employed. In the pH adjustment process employing the batch method described above, the number of agitation, the agitation time, or the amount or type of anion exchange resin used can be adjusted as appropriate.

  In the method of the present invention, the urea removal step, the pH adjustment step, and the order of execution are arbitrary. For example, in the present invention, at least one of the embodiment in which the urea removal step is performed and then the pH adjustment step is performed, the pH adjustment step is performed and then the urea removal step is performed, and the urea removal step and the pH adjustment step are performed. A mode in which parts overlap with time is included. That is, in any method including the column method or the batch method, the cation exchange resin and the anion exchange resin may be separately accommodated, and the urea removal step and the pH adjustment step may be performed independently of each other. . Alternatively, some or all of the cation exchange resin and the anion exchange resin may be accommodated together (so-called mixed bed), and the urea removal step and the pH adjustment step may overlap with time.

  For example, in the method of the present invention, an embodiment in which the pH adjustment step is performed after the urea removal step is one of the preferred embodiments. By performing each step in this order, both urea removal and pH adjustment can be performed reliably.

For example, the method of the present invention preferably includes one of a cation exchange resin regeneration step and an anion exchange resin regeneration step, and includes both a cation exchange resin regeneration step and an anion exchange resin regeneration step. Is more preferable.
The cation exchange resin regeneration step is a step of regenerating the cation exchange resin by bringing the cation exchange resin into contact with the first chemical after the urea removal step. More specifically, the cation exchange resin regeneration step is a step of desorbing the urea from the cation exchange resin by bringing the first chemical solution into contact with the cation exchange resin to which urea has adhered by performing the urea removal step. It is.

  The anion exchange resin regeneration step is a step of regenerating the anion exchange resin by bringing the anion exchange resin into contact with the second chemical after the pH adjustment step. More specifically, in the anion exchange resin regeneration step, after the pH adjustment step, the second chemical solution is brought into contact with the anion exchange resin, and again anions are released for adjusting the pH of the used dialysate. This is a process to make it possible.

  The cation exchange resin regeneration step and the anion exchange resin regeneration step in the method of the present invention may follow a method generally known as a method for regenerating the ion exchange resin used for ion exchange, and the purpose of the present invention Other methods may be adopted without departing from the above.

By regenerating the cation exchange resin used in the urea removal step and / or the anion exchange resin used in the pH adjustment step, the urea removal step and / or the pH adjustment step can be repeatedly performed. That is, the method of the present invention including the cation exchange resin regeneration step and / or the anion exchange resin regeneration step can regenerate the dialysate repeatedly.
In order to repeatedly perform the method of the present invention, it is preferable to include a cation exchange resin regeneration step and an anion exchange resin regeneration step. However, the method of the present invention is also applicable to an embodiment in which either one of the cation exchange resin and the anion exchange resin is regenerated by the regeneration step, and the other ion exchange resin is replaced with another one. Can be repeatedly performed.

As a 1st chemical | medical solution used for a cation exchange resin, acidic aqueous solution, such as hydrochloric acid and a sulfuric acid, can be used, for example, However, It is not limited to this.
For example, in the cation exchange resin regeneration step in the present invention, alcohol may be used as the first chemical solution.

  In general, alcohol is not selected as a chemical solution used to regenerate cation exchange resin, but it removes urea at a high removal rate by using alcohol to regenerate cation exchange resin with urea attached. It became clear by the inventor's investigation that this is possible. The reason for this is not clear. However, urea has a high solubility in alcohol, such as about 167 g dissolved in 1 L of methanol having a concentration of 99.8% or more and about 50 g dissolved in 1 L of ethanol having a concentration of 99.8% or more. Therefore, it is estimated that urea adhering to the cation exchange resin is desorbed from the cation exchange resin by dissolving in the alcohol used as the first chemical solution. Examples of the alcohol include methanol or ethanol, but are not limited thereto.

  Alcohol can be easily recovered by distillation means. The alcohol used as the first chemical solution in the cation exchange resin regeneration step contains urea. By supplying the alcohol containing urea to the distillation apparatus, it is possible to recover the alcohol not containing urea, and it can be used again as the first chemical solution in the cation exchange resin regeneration step. Therefore, when it is planned to repeatedly carry out the method of the present invention, it is preferable to further comprise a distillation step for distilling and recovering the alcohol used in the cation exchange resin regeneration step. However, the present invention does not exclude discarding the alcohol used in the cation exchange resin regeneration step.

  The alcohol used as the first chemical solution has, for example, a concentration of 70% or more, preferably a concentration of 80% or more, more preferably a concentration of 90% or more, still more preferably a concentration of 95% or more, and a concentration of 99% or more. Are particularly preferred. More specifically, in the present invention, an alcohol having a purity of 99.5% which is a reagent grade 1 or an alcohol having a purity of 99.8% which is a reagent special grade is particularly preferably used.

  Conventionally, as a recovery method for recovering alcohol in a high yield from an aqueous solution containing an organic compound or the like and alcohol, as described in Patent Document 3, an appropriate additive is added to the aqueous solution, methanol, A method for recovering organic compounds and the like has been proposed. On the other hand, as described above, the present invention uses a high-concentration alcohol as the first chemical solution. Therefore, no special additive is required, and the alcohol used in the cation exchange resin regeneration step can be recovered with high yield by distillation.

  As the second chemical solution used for the anion exchange resin, for example, an alkaline aqueous solution containing a hydroxide such as sodium hydroxide or potassium hydroxide can be used. When an anion exchange resin regeneration process is carried out using such a second chemical solution, water is generated and other salts are not easily generated. Therefore, a large amount of impurities are present between the regenerated anion exchange resins. Do not mix. Therefore, when implementing this invention repeatedly, it is hard to mix the said contaminant in the used dialysate which contacts an anion exchange resin. Here, the salt means a compound in which a cation derived from a cation exchange resin and an anion derived from an anion exchange resin are ion-bonded.

By performing the urea removal step and the pH adjustment step described above, it is possible to obtain a regenerated dialysis solution in which the urea is removed and the pH is adjusted.
In the present invention, the method of the present invention can be repeatedly performed by performing the cation exchange resin regeneration step after the urea removal step and performing the anion exchange resin regeneration step after the pH removal step. In the method of the present invention performed repeatedly, the contact conditions of the used dialysate and the anion exchange resin may be the same or different in the Nth pH adjustment step and the N-1th pH adjustment step. (N is an integer of 2 or more).

For example, a urea removal step using a first used dialysate obtained by performing a urea removal step using an unused cation exchange resin and a cation exchange resin subjected to a cation exchange resin regeneration step The pH of the second used dialysate obtained by performing may be different. In particular, the pH of the second used dialysate tends to be higher than the pH of the first used dialysate (hereinafter, this tendency is also referred to as “progression of basification”). This has been found by the study of the present inventors. In addition, the basification progress tendency is remarkably observed after the first cation exchange resin regeneration step, and is the trend moderate for the cation exchange resin after the second cation exchange resin regeneration step? Or may not occur substantially. The details of such examination are specifically shown in the first test and the second test in Examples described later. From such knowledge, it is a preferable aspect of the method of the present invention to relax the contact condition between the used dialysate and the anion exchange resin in the second pH adjustment step rather than the first pH adjustment step. One can say. Here, the relaxation of the conditions for contact between the used dialysate and the anion exchange resin is exemplified by any one or a combination of the following modes.
(A) In the column system, in the second pH adjustment step with respect to the first pH adjustment step,
(A-1) Decreasing the amount of anion exchange resin packed in the column, or
(A-2) The flow rate of the used dialysate that has undergone the urea removal step that is dropped onto the column is increased.
(B) In the batch method, in the second pH adjustment step with respect to the first pH adjustment step,
(B-1) reducing the amount of anion exchange resin used, or
(B-2) In the stirring and mixing of the anion exchange resin and the used dialysate that has undergone the urea removal step, the stirring time is shortened or the number of stirrings per unit time is decreased.

  Depending on the type of anion exchange resin to be selected, there is a tendency that the pH adjustment ability of the anion exchange resin decreases due to the anion exchange resin regeneration step (hereinafter, this tendency is also referred to as “acidification progress tendency”). In some cases. In this case, the above-described basification progress tendency and the acidification progress tendency are balanced, and as a result, even if the conditions of the first pH adjustment step and the second pH adjustment step are the same. By each treatment, it is possible to obtain a regenerated dialysate exhibiting the same pH. Here, the same pH means not only the case where the pH values completely match, but also the case where the difference in pH between each other is small, for example, the case where the difference in pH between each other is within 0.5.

Or the method of this invention can also employ | adopt the following aspects in view of the basification progress tendency mentioned above.
That is, the method of the present invention may use a preconditioned cation exchange resin and repeat the urea removal step and the pH adjustment step, and the cation exchange resin regeneration step and the anion exchange resin regeneration step. Here, the pre-adjusted cation exchange resin is a cation exchange resin in which urea contained in the urea-containing liquid is adhered by contacting with the urea-containing liquid in advance, and then the urea is removed by contacting with the chemical liquid. It is a regenerated cation exchange resin.

In this embodiment using the preconditioned cation exchange resin, the urea-containing liquid may be a used dialysis liquid or an artificially prepared urea-containing liquid. The artificially prepared urea-containing liquid is preferably adjusted to a urea concentration in the range of 300 mg / l to 400 mg / l in order to approximate the urea concentration in the used dialysate, for example.
Moreover, since the chemical | medical solution used in order to obtain a preconditioning cation exchange resin in this aspect is the same as the 1st chemical | medical solution mentioned above, detailed description is omitted here.

  The pre-adjusted cation exchange resin is preliminarily subjected to adsorption of urea and a regeneration step for removing it. Although the basification progress tendency of the selected cation exchange resin is remarkably observed after passing through the first cation exchange resin regeneration step, the cation exchange resin after the second cation exchange resin regeneration step is used. If it is slow, it is preferable to use a preconditioned cation exchange resin. When the method of the present invention is repeatedly carried out using a pre-adjusted cation exchange resin, the pH of the spent dialysate that has undergone the urea removal step can exhibit the same pH in the first time and the second time and thereafter. It is because it is not necessary to change the conditions of the pH adjustment process performed.

  Accordingly, the present invention proposes a preconditioned cation exchange resin as the cation exchange resin used in the dialysate regeneration method of the present invention. The preconditioned cation exchange resin is characterized in that the urea contained in the urea-containing liquid is adhered by contacting with the urea-containing liquid and then subjected to preconditioning to remove the urea by contacting with the chemical liquid. A cation exchange resin. By receiving the preliminary adjustment, urea is desorbed from the cation exchange resin, and the cation exchange resin is regenerated. Here, the urea-containing liquid and the chemical liquid are the same as those described in the above embodiment of the present invention using the pre-adjusted cation exchange resin, and thus detailed description thereof is omitted.

<First embodiment>
Below, 1st embodiment of the apparatus of this invention is described using FIG. FIG. 1 is a conceptual diagram of a dialysate regeneration device 100 (hereinafter also simply referred to as device 100) according to the first embodiment of the present invention.
In addition, the apparatus 100 in this embodiment can implement the method of this invention. With respect to the apparatus 100, reference is made, where appropriate, to the description of the method of the invention.

  The dialysate regenerator 100 includes a urea removal tank 130 for bringing the used dialysate 22 into contact with the cation exchange resin 80, and a pH adjusting tank 140 for bringing the used dialysate 22 into contact with the anion exchange resin 90. Have. As a result, the dialysate regenerator 100 can perform the method of the present invention. In one apparatus, urea can be removed from the used dialysate 22 and the pH of the resulting regenerated dialysate 52 can be adjusted. it can.

  The urea removal tank 130 in the apparatus 100 includes various modes as long as the used dialysate 22 can be brought into contact with the cation exchange resin 80. Moreover, the pH adjustment tank 140 includes various modes as long as the used dialysate 22 can be brought into contact with the anion exchange resin 90. For example, the urea removal tank 130 may be a column filled with the cation exchange resin 80 or a mixing device capable of stirring and mixing the used dialysate 22 and the cation exchange resin 80. The pH adjusting tank 140 may be a column filled with the anion exchange resin 90 or a mixing device capable of stirring and mixing the used dialysate 22 and the anion exchange resin 90. As a specific example, a column-type urea removal step and a pH adjustment step are performed by the urea removal tank 130 and the pH adjustment tank 140 which are the above-described columns. As another example, a batch urea removal step and a pH adjustment step are performed in the mixing apparatus. As another example, one of the urea removal tank 130 and the pH adjustment tank 140 may be a column, and the other may be a mixing device. As another example, a so-called mixed bed in which the urea removal tank 130 and the pH adjustment tank 140 are a common tank may be used.

  The apparatus 100 of the present embodiment includes a pH adjustment tank 140 on the downstream side of the urea removal tank 130. The urea removal tank 130 and the pH adjustment tank 140 are connected in series. By providing each tank in this order, performing the urea process, and then performing the pH adjustment process, both urea removal and pH adjustment can be performed reliably.

Details of the apparatus 100 will be described below with reference to FIG.
The apparatus 100 includes a urea removal tank 130 filled with a cation exchange resin 80. In the present embodiment, the apparatus 100 including one urea removal tank 130 will be described as an example, but the number of urea removal tanks 130 can be changed as appropriate. For example, the urea removal tank 130 may be configured by connecting two or more columns filled with the cation exchange resin 80 in series. The urea removal tank 130 is filled with a cation exchange resin 80 capable of adhering urea contained in a used dialysate 22 described later. The cation exchange resin 80 to be filled may be one cation exchange resin or two or more cation exchange resins having different chemical structures.

  The urea removal tank 130 is connected to the processing liquid tank 20 in which the used dialysate 22 is accommodated by a flowable line 112, and the used dialysate 22 is appropriately transferred from the processing liquid tank 20 to the urea removal tank 130. Is sent. In the description of the present specification, the term “line” means a flow path through which a liquid material can flow unless otherwise specified. For example, the used dialysate 22 may be sent to the processing solution tank 20 from another device such as an artificial dialysis device through a line not shown.

  The used dialysate 22 is fed into the urea removal tank 130 through the line 112, and the cation exchange resin 80 and the used dialysate 22 come into contact with each other, and the urea contained in the used dialysate 22 is subjected to cation exchange. It adheres to the resin 80. As a result, the urea removal step is performed in the apparatus 100.

The urea removal tank 130 and the pH adjustment tank 140 are connected by a line 113. The line 113 is a discharge path for discharging the used dialysate 22 in contact with the cation exchange resin 80 in the urea removal tank 130 and the used dialysate in contact with the cation exchange resin 80 in the urea removal tank 130. This is an injection path for injecting 22 into the pH adjustment tank 140.
The pH adjustment tank 140 is connected to the treated liquid tank 50 by a line 114. The used dialysate 22 sent to the pH adjustment tank 140 through the line 113 comes into contact with the anion exchange resin 90 accommodated in the pH adjustment tank 140. Thus, the pH adjustment step is performed. The used dialysate 22 processed in the urea removal tank 130 and the pH adjustment tank 140 is discharged from the line 114 as the regenerated dialysate 52 and sent to the processed liquid tank 50.
In the present embodiment, the line 114 is provided with an on-off valve 125. The on-off valve 125 is opened in the apparatus 100 when the urea removal step and the pH adjustment step are performed, and is closed when the cation exchange resin regeneration step or the anion exchange resin regeneration step described later is performed. .

  In the present embodiment, the cation exchange resin 80 to which urea is attached exists in the urea removal tank 130 after the urea removal step is completed. Further, in the pH adjustment tank 140 after the pH adjustment process is completed, there is an anion exchange resin 90 after adjusting the pH of the used dialysate 22 discharged from the urea removal tank 130 and inclined to the acidic side. The apparatus 100 according to the present embodiment regenerates the cation exchange resin 80 after the urea removal step and the anion exchange resin 90 after the pH adjustment step, so that an appropriate chemical solution is brought into contact with each ion exchange resin and regenerated. Reproducing means is provided as follows.

  That is, in the apparatus 100, the urea removal tank 130 has a first injection path 118A for injecting the first chemical liquid 32 for regenerating the cation exchange resin 80, and a first discharge path 132A for discharging the first chemical liquid 32. . In addition, the pH adjustment tank 140 is for discharging the second chemical liquid 36 and the second chemical liquid 36 that are different from the first chemical injection path 118A for injecting the second chemical liquid 36 for regenerating the anion exchange resin 90. A second discharge path 132B different from the first discharge path 132A is provided.

  The apparatus 100 includes a first chemical liquid tank 30 that contains the first chemical liquid 32 and a second chemical liquid tank 34 that contains the second chemical liquid 36. The first chemical tank 30 is connected to the urea removal tank 130 via the first injection path 118A. The second chemical tank 34 is connected to the pH adjustment tank 140 via the second injection path 118B.

  By providing such a regeneration means, the cation exchange resin regeneration step and the anion exchange resin regeneration step can be performed in the apparatus 100. By performing the cation exchange resin regeneration step, the cation exchange resin 80 is regenerated to recover the urea adhesion ability. In addition, by performing the anion exchange resin regeneration step, the anion exchange resin 90 is regenerated and the pH adjusting ability for adjusting the pH of the used dialysate 22 is restored. As a result, it is possible to regenerate the used dialysate 22 repeatedly in the apparatus 100. In the present embodiment, the first injection path 118A and the second injection path 118B, and the first discharge path 132A and the second discharge path 132B are independent of each other. Therefore, the first chemical solution 32 and the second chemical solution 36 are mixed until the regeneration means is finished, the first chemical solution 32 is discharged from the urea removal tank 130, and the second chemical solution 36 is discharged from the pH adjustment tank 140. There is nothing. Therefore, when recovering the first chemical liquid 32 or the second chemical liquid 36, a reduction in the recovery rate due to the mixing of the chemical liquids is avoided.

  In addition, the apparatus 100 of this embodiment shows an example in which the cation exchange resin regeneration process is performed in the urea removal tank 130 and the anion exchange resin regeneration process is performed in the pH adjustment tank 140. However, the reproducing means of the apparatus 100 is not limited to this. The regeneration means contacts the cation exchange resin 80 to which urea is adhered and the first chemical liquid 32, and the anion exchange resin 90 and the second chemical liquid 36 after being used for pH adjustment of the used dialysate 22 Can be appropriately designed within a range in which can be contacted. For example, although not shown, the cation exchange resin regeneration process may be performed in a tank different from the urea removal tank 130 in the apparatus 100, or the anion exchange resin regeneration process in a tank or apparatus different from the pH adjustment tank 140. May be implemented.

In the apparatus 100, the first chemical liquid 32 injected into the urea removal tank 130 is separated from the cation exchange resin 80 after the cation exchange resin regeneration step is performed. Specifically, in the present embodiment, the used first chemical liquid 32 is discharged from the urea removal tank 130 via the first discharge path 132A.
Further, in the apparatus 100, the second chemical liquid 36 injected into the pH adjustment tank 140 is separated from the anion exchange resin 90 after the anion exchange resin regeneration step is performed. Specifically, in this embodiment, the used second chemical liquid 36 is discharged from the pH adjustment tank 140 through the second discharge path 132B.

The apparatus 100 of the present embodiment has a distillation unit 60 and / or a waste liquid tank 70. The first chemical liquid 32 discharged from the urea removal tank 130 and the second chemical liquid 36 discharged from the pH adjustment tank 140 are sent to the distillation unit 60 or the waste liquid tank 70, respectively.
For example, when the first chemical liquid 32 discharged from the urea removal tank 130 is regenerated, it is as follows. That is, the first chemical liquid 32 is discharged from the urea removal tank 130 through the first discharge path 132A, which is a discharge path provided in the urea removal tank 130, and flows through the line 132 and the line 128 connected to the first discharge path 132A. Then, it is sent to the distillation unit 60. The first chemical liquid 32 may be discharged from the urea removal tank 130 through the first discharge path 132A, and may be sent to the waste liquid tank 70 through the line 132 and the line 126 connected to the first discharge path 132A. The same applies to the second chemical liquid 36 discharged from the pH adjustment tank 140.

As a more specific preferable example, in the apparatus 100, the first chemical liquid 32 is alcohol, and the apparatus 100 includes a distillation unit 60 that distills the alcohol (first chemical liquid 32) discharged from the urea removal tank 130.
On the other hand, the second chemical liquid 36 is, for example, sodium hydroxide or potassium hydroxide, and is discharged from the pH adjustment tank 140 and then fed into the waste liquid tank 70.
Thus, by collecting the first chemical liquid 32 by distillation, it is possible to reuse the used alcohol (first chemical liquid 32) in the cation exchange resin regeneration step.

  The distillation unit 60 includes, for example, an evaporator that can recover the alcohol that is the first chemical liquid 32 by distillation under reduced pressure. In the present embodiment, as shown in FIG. 1, the distillation unit 60 is connected to the first chemical tank 30 by a line 150. The first chemical liquid 32, which is the alcohol distilled and collected by the distillation section 60, is discharged from the distillation section 60, sent to the first chemical tank 30 through the line 150, and again used for the cation exchange resin regeneration step. obtain.

  The apparatus 100 according to this embodiment includes a three-way valve 124 at a branch point between the line 132, the line 126, and the line 128. The three-way valve 124 can selectively circulate a liquid material (that is, the first chemical liquid 32 or the second chemical liquid 36) flowing from the line 132 to the line 126 or the line 128. For example, the three-way valve 124 can be switched electromagnetically or manually to completely shut off the liquid material flowing from the line 132, to flow to the line 128, or to flow to the line 126.

The apparatus 100 includes a cleaning liquid tank 40 in which a cleaning liquid 42 such as pure water is accommodated. In the present embodiment, the cleaning liquid tank 40 is disposed in parallel with each of the first chemical liquid tank 30 and the second chemical liquid tank 34. The cleaning liquid 42 sent out from the cleaning liquid tank 40 provided in parallel with the first chemical liquid tank 30 can be injected into the urea removal tank 130 via the line 116A and the first injection path 118A. The cleaning liquid 42 sent out from the cleaning liquid tank 40 provided in parallel with the second chemical liquid tank 34 can be injected into the pH adjustment tank 140 through the line 116B and the second injection path 118B. The first injection path 118A is provided with a pump 120. When the first chemical liquid 32 or the cleaning liquid 42 is circulated through the urea removal tank 130, pressure is appropriately applied to the first chemical liquid 32 or the cleaning liquid 42 in a predetermined direction. be able to. Similarly, the pump 120 is also provided in the second injection path 118B, and when the second chemical liquid 36 or the cleaning liquid 42 is circulated through the pH adjustment tank 140, the second chemical liquid 36 or the cleaning liquid 42 is appropriately transferred in a predetermined direction. Pressure can be applied.
As a modification example not shown, the apparatus 100 may include one cleaning liquid tank 40 connected by a line branched to the urea removal tank 130 and the pH adjustment tank 140.

  The cleaning liquid 42 is appropriately injected from the cleaning liquid tank 40 into the urea removal tank 130 in which the cation exchange resin regeneration process has been performed or the pH adjustment tank 140 in which the anion exchange resin regeneration process has been performed. Thus, the cation exchange resin 80 accommodated in the urea removal tank 130 or the anion exchange resin 90 accommodated in the pH adjustment tank 140 can be washed.

By the way, the cation exchange resin 80 used in the apparatus 100 is preliminarily adjusted so that the urea contained in the urea-containing liquid is adhered by contacting with the urea-containing liquid in advance and then the urea is removed by contacting with the chemical liquid. A cation exchange resin may be used.
Since the description of the preconditioning cation exchange resin and the effect of using it are appropriately referred to those described in the method of the present invention, the detailed description is omitted here.

  The apparatus 100 shown in FIG. 1 includes a first discharge path 132A, a line 113, a second discharge path 132B, a line 116A, a first injection path 118A, the front side joining the line 116A, a line 116B, and a second injection path. On-off valves 125 are respectively provided on the front side that is 118B and merges with the line 116B. In the apparatus 100, the on-off valve 125 can be provided at an appropriate location as described above. The apparatus 100 may omit any of the on-off valves 125 illustrated in FIG. 1, or may further include different valves as necessary.

<Second embodiment>
Next, a second embodiment of the apparatus of the present invention will be described with reference to FIG. FIG. 2 is a conceptual diagram of a dialysate regeneration device 200 (hereinafter also simply referred to as device 200) according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in the following points. Of the configuration of the second embodiment, the description of the same configuration as the first embodiment will be omitted as appropriate.

  The apparatus 200 of 2nd embodiment has the common tank 10 which serves as a urea removal tank and a pH adjustment tank, and the cation exchange resin 80 and the anion exchange resin 90 are mixed and accommodated in the common tank 10. This is different from the apparatus 100 in that respect. The common tank 10 is a so-called mixed bed. By having the common tank 10, the structure of the apparatus 200 is simplified, the apparatus is reduced in size, and the handleability is also good. Moreover, since the apparatus 200 can simultaneously perform the urea removal step and the pH adjustment step in the common tank 10, it is possible to shorten the time for the regeneration process of the used dialysate 22.

That is, the used dialysate 22 sent from the processing solution tank 20 to the common tank 10 via the line 112 comes into contact with the cation exchange resin 80 and the anion exchange resin 90 at the same timing. Thereby, in the common tank 10, a urea removal process and a pH adjustment process are implemented in parallel. The regenerated dialysate 52 from which urea has been removed and whose pH has been adjusted is discharged from the common tank 10 through the line 114.
The common tank 10 from which the regenerated dialysate 52 has been discharged contains the cation exchange resin 80 to which urea has adhered and the anion exchange resin 90 used in the pH adjustment step.

  The apparatus 200 has a first chemical tank 30, a second chemical tank 34, and a cleaning liquid tank 40. The first chemical tank 30 is connected to the common tank 10 via a line 118. The second chemical tank 34 is connected to the common tank 10 via a line 116 and a line 118. The cleaning liquid tank 40 is connected to the common tank 10 via a line 117, a line 116, and a line 118. The first chemical liquid 32, the second chemical liquid 36, and the cleaning liquid 42 stored in each tank are appropriately pressurized in a predetermined direction by the pump 120.

For example, in the apparatus 200, an example of a mode in which the cation exchange resin 80 and the anion exchange resin 90 are regenerated is as follows.
First, the second chemical liquid 36 is sent from the second chemical liquid tank 34 to the common tank 10 and the anion exchange resin regeneration step is performed, and then the cleaning liquid 42 is appropriately sent from the cleaning liquid tank 40 to the common tank 10 to be common. The second chemical liquid 36 remaining in the tank 10 is washed away. Subsequently, the first chemical liquid 32 is sent from the first chemical liquid tank 30 to the common tank 10, and the cation exchange resin regeneration step is performed. Then, the cleaning liquid 42 is appropriately sent from the cleaning liquid tank 40 to the common tank 10, The first chemical liquid 32 remaining in the common tank 10 is washed away. Thereby, it is possible to satisfactorily carry out the cation exchange resin regeneration step and the anion exchange resin regeneration step while preventing the alkali ions derived from the second chemical liquid 36 from adhering to the cation exchange resin.
From the viewpoint of recovering the first chemical liquid 32 that is alcohol in a high yield, it is preferable that the timings at which the first chemical liquid 32 and the second chemical liquid 36 are fed into the common tank 10 are made different.
In the present embodiment, the first chemical tank 30 and the second chemical tank 34 may be omitted. In this embodiment, after the urea removal step and the pH adjustment step are performed, the cation exchange resin regeneration step and the anion exchange resin regeneration step are not performed, and the cation exchange resin 80 and the anion exchange resin 90 are replaced. May be.

  However, as described above, as another aspect of the apparatus 200, the first chemical liquid 32 and the second chemical liquid 36 are overlapped with time and sent to the common tank 10, and the cation exchange resin regeneration step and the anion exchange resin regeneration step are simultaneously performed. It does not exclude doing.

  In the apparatus 200 shown in FIG. 2, the opening / closing valve 125 is provided on the front side of the line 122, the line 116, the line 117, and the line 118, which joins the line 116 and the line 117. In the apparatus 200, the on-off valve 125 can be provided at an appropriate location as described above. The apparatus 200 may omit any of the on-off valves 125 illustrated in FIG. 2, or may further include different valves as necessary.

Although the first embodiment and the second embodiment of the method of the present invention, the preconditioned cation exchange resin of the present invention, and the apparatus of the present invention have been described above, the present invention is not limited to the above-described embodiments. In addition, various modifications and improvements as long as the object of the present invention is achieved are also included. The description of the method of the present invention and the description of the device of the present invention have many points in common with each other (for example, members used, methods employed, etc.), and one description is referred to the other as appropriate.
For example, in the first embodiment or the second embodiment, the common tank 10, the treatment liquid tank 20, the urea removal tank 130, the pH adjustment tank 140, the treated liquid tank 50, the distillation unit 60, the waste liquid tank 70, the first chemical liquid tank. 30 and the washing | cleaning-liquid tank 40 were connected by the line, respectively, and demonstrated the example which moves a liquid through the said line. However, the method or apparatus of the present invention is not limited to this, and any or all of the lines may be omitted, and the liquid material may be moved between each tank or section by other means including manual operation.
In FIGS. 1, 2, and 4, for the sake of easy visual recognition, the on-off valve 125 is provided in the middle of each line, but this does not define the installation position of the on-off valve 125. The on-off valve 125 may be appropriately disposed at the upstream side or downstream side of the line, or at the intersection between the line and an arbitrary tank.
Further, the lines shown in FIG. 1 or FIG. 2 can be merged with each other to be a common line or can be independent from each other without departing from the spirit of the present invention.

Examples, Comparative Examples, Reference Examples, and Test Examples of the present invention were carried out as follows. In addition, the following were used for the ion exchange resin used for each Example and each comparative example, the urea containing liquid which is an alternative of a used dialysate, a flask, and a column.
<Strongly acidic cation exchange resin A>
RCP160M (high porous type strongly acidic cation exchange resin) manufactured by Mitsubishi Chemical Corporation was used.
<Strongly acidic cation exchange resin B>
Amberlyst 15H (high porous type strongly acidic cation exchange resin) provided by Wako Pure Chemical Industries, Ltd. was used.
<Strongly acidic cation exchange resin C>
Amberlyst 15H (DRY) (high porous type strongly acidic cation exchange resin) provided by Organo Corporation was used.
<Weak basic anion exchange resin>
Amberlite IRA96SB (weakly basic anion exchange resin) provided by Organo Corporation was used.
<Strongly basic anion exchange resin>
Amberlite IRA900 (OH) (strongly basic anion exchange resin) provided by Organo Corporation was used.
<Urea-containing liquid>
It was prepared by adding commercially available urea to pure water and adjusting the urea concentration to 350 mg / l. When the pH of the urea-containing liquid was measured, it was pH 5.6.
<Flask>
A conical stoppered Erlenmeyer flask with a capacity of 200 ml was used.
<Column>
A chromatograph tube of 12φ (body inner diameter 12 mm) × 300 mm was used.

Example 1
A first flask charged with 20 g of strongly acidic cation exchange resin A and 50 ml of urea-containing liquid was prepared. A stirrer was put into the first flask, and the urea removal step was performed by stirring at room temperature for 1 hour under stirring conditions of 500 rpm. Centrifugation was performed after stirring, and then the urea-containing liquid and the strongly acidic cation exchange resin were separated by filtration with a 50 μm filter to obtain a treated liquid A.
A second flask filled with the entire amount of the treated liquid A and 20 g of weakly basic anion exchange resin was prepared. The second flask was charged with a stirrer and stirred for 1 hour at room temperature under stirring conditions of 500 rotations / minute to carry out a pH adjustment step. Centrifugation was performed after stirring, and then the treated liquid A and the weakly basic anion exchange resin were separated by filtration with a 50 μm filter to obtain a treated liquid B.

(Examples 2 and 4)
Examples 2 and 4 were carried out except that the type and amount of cation exchange resin used in the urea removal step were changed to those shown in Table 1 and that a strongly basic ion exchange resin was used in the pH adjustment step. A urea removal step and a pH adjustment step were carried out in the same manner as in Example 1, and treated liquid B was obtained.
(Example 3)
As Example 3, the urea removal step and the pH adjustment step were carried out in the same manner as in Example 1 except that the type and addition amount of the cation exchange resin used in the urea removal step were changed to the contents shown in Table 1, and the treatment was performed respectively. Spent solution B was obtained.

  The pH of the treated liquid B obtained in each example was measured, and the results are shown in Table 1.

(Comparative Example 1)
As Comparative Examples 1 to 3, the urea removal step was performed in the same manner as in Example 1 except that the type and addition amount of the cation exchange resin used in the urea removal step were changed to those shown in Table 1. In Comparative Examples 1 to 3, the pH adjustment step was not performed. The pH of the treated liquid A obtained by performing the urea removal step in each comparative example was measured, and the results are shown in Table 1.

(Reference Examples 1 to 3)
As Reference Examples 1 to 3, a urea removal step was performed in the same manner as Comparative Examples 1 to 3 except that ultrapure water having a pH of 7 was used instead of the urea-containing liquid, and treated liquid A was obtained. The pH of the treated liquid A obtained by carrying out the urea removal step in each reference example was measured, and the results are shown in Table 1.

As shown in Table 1, it was confirmed that the pH of the treated liquid A obtained in each comparative example and each reference example was greatly inclined to be acidic compared to the pH before the urea removal step. From this result, it was suggested that the used dialysate obtained by carrying out the urea removal step of the present invention is biased toward acidity.
On the other hand, the pH of the treated liquid B obtained in each example was biased toward the alkali side. From this result, it was confirmed that the pH of the urea-containing liquid was adjusted in the subsequent pH adjustment step, although it was biased to acidity after the urea removal step. That is, it was confirmed that the method of the present invention including the pH adjusting step can adjust the pH in the regeneration of the used dialysate.

  Next, the following tests were performed using the test apparatus 400 shown in FIG. 4 as a study on the urea removal ability confirmation and the regeneration of the cation exchange resin in the method of the present invention. The test was performed based on the flow shown in FIG. 3A or FIG. 3B. FIG. 3A is a flow of a first test in which the urea removal step is repeated three times in the embodiment of the present invention including the cation exchange resin regeneration step. FIG. 3B is a flow of a second test in which the urea removal step is repeated twice in the embodiment of the present invention including the cation exchange resin regeneration step. FIG. 4 is an overall view of a test apparatus 400 for performing the first test and the second test. The test apparatus 400 contains the treatment liquid tank 20 containing the urea-containing liquid 23, the chromatographic tube 300 filled with the cation exchange resin 310, the first chemical liquid tank 30 containing the first chemical liquid 32, and the cleaning liquid 42. The cleaning liquid tank 40, the treated liquid tank 50 in which each urea removing liquid (urea removing liquids 312, 314, 316, 318, 320) is stored, the waste liquid tank 70 in which the discarded first chemical liquid 32 and the cleaning liquid 42 are stored. These are connected directly or indirectly by the lines shown in FIG. In the test apparatus 400 shown in FIG. 4, a line 118 that connects the first chemical tank 30 and the chromatographic tube 300, a front side that joins the line 116 </ b> A, and a line that joins the cleaning liquid tank 40 and joins the line 118. An opening / closing valve 125 is provided at 116A. The on-off valve 125 provided in the line 118 was opened when the first chemical solution 32 was injected into the chromatographic tube 300, and was closed otherwise. The on-off valve 125 provided in the line 116A was opened when the cleaning liquid 42 was injected into the chromatographic tube 300, and was closed otherwise.

[First test]
The first test was conducted as follows. First, a chromatographic tube 300 filled with 20 g of unused cation exchange resin 310 (NEW) was prepared. Moreover, the urea containing liquid 23 was used as an alternative of a used dialysate. As the cation exchange resin 310, strong acid cation exchange resin A was used.

The urea-containing liquid 23 was dropped into the chromatographic tube 300 over 1 hour, and the urea removing step S330 was performed to obtain a urea removing liquid 312 discharged from the chromatographic tube 300. The urea removing liquid 312 was stored in the treated liquid tank 50 through lines 113 and 113A.
As described above, 50 ml of methanol having a concentration of 99.5% as the first chemical solution 32 is dropped over 1 hour on the chromatographic tube 300 in which the urea removal step S330 has been performed, and then 200 ml of pure water 42 is dropped over 1 hour. The cation exchange resin regeneration step S340 was performed.

  Next, the urea removal step S350 is carried out in the same manner as the urea removal step S330 except that the chromatographic tube 300 is filled with the cation exchange resin 310 (regenerated once) regenerated in the cation exchange resin regeneration step S340. Thus, a urea removal solution 314 was obtained. And cation exchange resin regeneration process S360 was implemented similarly to cation exchange resin regeneration process S340.

  Next, the urea removal step S370 is performed in the same manner as the urea removal step S330 except that the chromatographic tube 300 is filled with the cation exchange resin 310 regenerated by the cation exchange resin regeneration step S360 (regenerated twice). Thus, a urea removing solution 316 was obtained. This completed the first test.

[Second test]
Following the first test, the urea removal step S330 was performed to obtain a urea removal solution 318.
Next, the cation exchange resin regeneration step S410 is the same as the cation exchange resin regeneration step S340 except that 200 ml of 1N hydrochloric acid is used instead of methanol as the first chemical solution 32 used in the cation exchange resin regeneration step S410. Carried out.

  Next, the urea removal step S420 is performed in the same manner as the urea removal step S330 except that the chromatographic tube 300 is filled with the cation exchange resin 310 (regenerated once) regenerated in the cation exchange resin regeneration step S410. Thus, the urea removal solution 320 was obtained and the second test was completed.

  The pH and urea concentration of the urea removal solutions 312, 314, 316, 318, and 320 obtained in the first test and the second test described above were measured and are shown in Table 2. Further, the urea removal rate was determined from the measured urea concentration and is shown in Table 2 together. The measurement of the urea concentration and the calculation of the urea removal rate were performed as follows.

(Measurement of urea concentration)
The urea concentration of the urea removal solutions 312, 314, 316, 318, and 320 obtained in each test example was measured by the Kjeldahl method.
Specifically, each urea removal solution and ammonium ion standard solution were subjected to an ion chromatograph, and the ammonium ion concentration in each sample was determined by a calibration curve method. An ICS3000 type ion chromatograph manufactured by Nippon Dionex Co., Ltd. was used as the ion chromatograph.
Next, the nitrogen concentration in each sample was converted from the ammonium ion concentration obtained above, and the urea concentration (mg / l) was determined by the following formula 1 using this.
(Formula 1) Urea concentration (mg / l) = nitrogen concentration (mg / l) × (molecular weight of urea / molecular weight of nitrogen in urea)

(Calculation of urea removal rate)
Moreover, the urea removal rate was calculated | required by the following formula 2 about each urea removal liquid obtained in the 1st test and the 2nd test.
(Expression 2) Urea removal rate (%) = [(Urea concentration in urea-containing solution (mg / l) −Urea concentration in urea-removed solution (mg / l)) / Urea concentration in urea-containing solution (mg / l)] × 100

As shown in Table 2, each of the urea removal solutions has a high urea removal rate of 90% or more, and the urea removal step is performed by directly contacting the urea-containing solution and the cation exchange resin to increase the urea. It was confirmed that it can be removed efficiently.
For example, in the first test, the urea removal step was repeated three times by regenerating and repeatedly using the same cation exchange resin. As a result, each urea removal solution showed a high urea removal rate. Thus, it was confirmed that the method of the present invention can be repeatedly performed.

The following knowledge about the pH of the urea removal solution was obtained. That is, the urea removal liquid 312 and the urea removal liquid 318 obtained in the urea removal step S330 performed using an unused cation exchange resin both had a pH of 3.4.
In contrast, the urea removal solution 314 and the urea removal solution 320 obtained in the urea removal step S350 and the urea removal step S420 performed using the once regenerated cation exchange resin 310 both have a pH higher than 5. There was a tendency toward basification.

  In the first test, the urea removal solution 316 obtained in the urea removal step S370 performed using the cation exchange resin 310 that has been regenerated twice showed a pH that approximated the urea removal solution 314. From the above, it was suggested that the cation exchange resin has a remarkably advanced basification tendency when regenerated once, but the basification progress tendency is moderate after the second recycle. .

The above embodiment includes the following technical idea.
(1) A urea removal step in which a used dialysate used for artificial dialysis is brought into contact with a cation exchange resin, and urea contained in the used dialysate is adhered to the cation exchange resin;
And a pH adjusting step of adjusting the pH of the used dialysate by bringing the used dialysate into contact with an anion exchange resin.
(2) The dialysate regeneration method according to (1), wherein the pH adjustment step is performed after the urea removal step.
(3) a cation exchange resin regeneration step for regenerating the cation exchange resin by bringing it into contact with the first chemical after the urea removal step;
A dialysate regeneration method according to (1) or (2), comprising: an anion exchange resin regeneration step in which the anion exchange resin is regenerated by contacting the second chemical after the pH adjustment step.
(4) The dialysate regeneration method according to the above (3), wherein the first chemical solution is alcohol.
(5) The dialysate regeneration method according to the above (3) or (4), wherein the second chemical solution is a hydroxide.
(6) As the cation exchange resin, the urea contained in the urea-containing liquid is attached in advance by contacting with the urea-containing liquid, and then the urea is removed and regenerated by contacting with the chemical liquid. Using ion exchange resin,
The dialysate regeneration method according to any one of (3) to (5), wherein the urea removal step and the pH adjustment step, and the cation exchange resin regeneration step and the anion exchange resin regeneration step are repeated.
(7) A cation exchange resin used in the dialysate regeneration method according to any one of (1) to (6) above, wherein urea is contained in the urea-containing liquid by contact with the urea-containing liquid. A preconditioned cation exchange resin that has been subjected to a preconditioning in which urea is removed by adhering to and then contacting with a chemical solution.
(8) a urea removal tank in which the used dialysate is brought into contact with a cation exchange resin;
A dialysate regenerator, comprising: a pH adjusting tank for bringing the used dialysate into contact with an anion exchange resin.
(9) The pH adjustment tank is provided on the downstream side of the urea removal tank,
The dialysate regenerator according to (8), wherein the urea removal tank and the pH adjustment tank are connected in series.
(10) The urea removal tank has a first injection path for injecting a first chemical liquid for regenerating the cation exchange resin, and a first discharge path for discharging the first chemical liquid,
The pH adjustment tank has a second injection path different from the first injection path for injecting the second chemical liquid for regenerating the anion exchange resin, and the first chemical for discharging the second chemical liquid. The dialysate regenerator according to (8) or (9) above, which has a second discharge path different from the discharge path.
(11) The dialysate regenerator according to (10), wherein the first chemical solution is alcohol and has a distillation section for distilling the alcohol discharged from the first chemical solution.
(12) A pre-adjusted cation exchange resin in which the cation exchange resin is preliminarily contacted with a urea-containing liquid to attach urea contained in the urea-containing liquid and then contacted with a chemical liquid to remove the urea. The dialysate regenerator according to any one of (8) to (11) above.

DESCRIPTION OF SYMBOLS 10 ... Common tank 20 ... Processing liquid tank 22 ... Used dialysate 23 ... Urea containing liquid 30 ... First chemical liquid tank 32 ... First chemical liquid 34 ... Second chemical liquid Tank 36 ... Second chemical liquid 40 ... Cleaning liquid tank 42 ... Cleaning liquid 50 ... Processed liquid tank 52 ... Regenerated dialysate 60 ... Distillation unit 70 ... Waste liquid tank 80 ... Cation exchange resin 90 ... anion exchange resin 100, 200 ... dialysate regenerators 112, 113, 113A, 113B, 114, 116, 116A, 116B, 117, 118, 126, 128, 132, 150 ..Line 118A ... first injection path 118B ... second injection path 120 ... pump 124 ... three-way valve 125 ... open / close valve 130 ... urea removal tank 132A ... first discharge Path 132B ... second discharge path 140 ... pH adjustment 300 ... Chromatic tube 310 ... Cation exchange resin 312, 314, 316, 318, 320 ... Urea removal solution 400 ... Test apparatus S330, S350, S370, S420 ... Urea removal step S340, S360, S410 ... Cation exchange resin regeneration process

Claims (12)

A urea removal step in which a used dialysis solution used for artificial dialysis is brought into contact with a cation exchange resin, and urea contained in the used dialysis solution is attached to the cation exchange resin;
And a pH adjusting step of adjusting the pH of the used dialysate by bringing the used dialysate into contact with an anion exchange resin.   The dialysate regeneration method according to claim 1, wherein the pH adjustment step is performed after the urea removal step. A cation exchange resin regeneration step for regenerating by contacting the cation exchange resin with a first chemical after the urea removal step;
The dialysate regeneration method according to claim 1, further comprising: an anion exchange resin regeneration step in which the anion exchange resin is regenerated by contacting the second chemical after the pH adjustment step.   The dialysate regeneration method according to claim 3, wherein the first chemical solution is alcohol.   The dialysate regeneration method according to claim 3 or 4, wherein the second chemical solution is a hydroxide. As the cation exchange resin, a pre-adjusted cation exchange resin in which urea contained in the urea-containing liquid is adhered by contacting with the urea-containing liquid in advance, and then the urea is removed and regenerated by contacting with the chemical liquid. Use
The dialysate regeneration method according to any one of claims 3 to 5, wherein the urea removal step and the pH adjustment step, and the cation exchange resin regeneration step and the anion exchange resin regeneration step are repeated. A cation exchange resin used in the dialysate regeneration method according to any one of claims 1 to 6,
A preconditioned cation exchange resin which has undergone a preconditioning in which urea contained in the urea-containing liquid is adhered by contacting with the urea-containing liquid and then urea is removed by contacting with the chemical liquid. A urea removal tank in which the used dialysate is brought into contact with a cation exchange resin;
A dialysate regenerator, comprising: a pH adjusting tank for bringing the used dialysate into contact with an anion exchange resin. The pH adjustment tank is provided downstream of the urea removal tank,
The dialysate regeneration apparatus according to claim 8, wherein the urea removal tank and the pH adjustment tank are connected in series. The urea removal tank has a first injection path for injecting a first chemical liquid for regenerating the cation exchange resin, and a first discharge path for discharging the first chemical liquid,
The pH adjustment tank has a second injection path different from the first injection path for injecting the second chemical liquid for regenerating the anion exchange resin, and the first chemical for discharging the second chemical liquid. The dialysate regeneration apparatus according to claim 8 or 9, wherein the dialysate regeneration apparatus has a second discharge path different from the discharge path.   The dialysis fluid regenerating apparatus according to claim 10, wherein the first chemical liquid is alcohol and has a distillation section for distilling the alcohol discharged from the first chemical liquid.   The cation exchange resin is a preconditioned cation exchange resin in which the urea contained in the urea-containing liquid is attached in advance by contacting with the urea-containing liquid, and then the urea is removed by contacting with the chemical liquid. Item 12. The dialysate regeneration device according to any one of Items 8 to 11.

Images