JP2001219161A - Water cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water cleaning apparatus provided with a reverse osmosis membrane device and an electric deionization device, capable of preventing the generation of scale and stably producing high-quality cleaned water. SOLUTION: A decarbonation device 2 using a strongly basic ion-exchange resin is installed after the reverse osmosis membrane device 1 and before the electric deionization device 3. Thereby, an anion load on the electric deionization device 3 can be remarkably decreased, and the generation of hardness scale in the electric deionization device 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for producing pure water, and more particularly, to an apparatus for producing ultrapure water having an extremely high water quality without generating a hardness scale in an apparatus for producing pure water provided with an electric deionization apparatus. And a pure water producing apparatus capable of obtaining the same stably.

[0002]

2. Description of the Related Art Conventionally, a system provided with an electric deionizer has been widely used as a pure water producing apparatus.

[0003] The electric deionization apparatus comprises a plurality of anion exchange membranes and a plurality of cation exchange membranes arranged alternately between an anode and a cathode, and a deionization chamber and a concentration chamber partitioned by the anion exchange membrane and the cation exchange membrane. While alternately forming a mixture of an anion exchange resin and a cation exchange resin in a desalination chamber to which the water to be treated is supplied, and applying a DC voltage between the anode and the cathode. The ionic component in the water to be treated, to which the mixture of the anion exchange resin and the cation exchange resin is adsorbed in the desalting chamber, is transferred to the concentration chamber by the action of a direct current to act to desalinate the water to be treated.

The advantage of the electric deionizer is that the ion component adsorbed on the mixture of the anion exchange resin and the cation exchange resin in the desalting chamber is continuously transferred to the concentration chamber by the action of a direct current. Regenerates the body, thereby continuously producing deionized water without using any chemicals to regenerate the ion exchange resin, such as acids or alkalis, regardless of the use of the ion exchange resin It is in the point which made possible.

[0005] On the other hand, while having such excellent advantages, in the electric desalination apparatus, when a hard component such as calcium and magnesium is present in the water to be treated and a total carbonic acid component is present, the ion exchange is performed by these reactions. There is a problem that a hardness scale is generated on the membrane, which increases the electric resistance between the anode and the cathode, reduces the flow rate on the concentration side, and eventually lowers the quality of treated water.

[0006] Due to such a problem, a reverse osmosis membrane device is generally arranged in front of the electric deionization device to remove dissolved salts (and TOC components). However, the removal rate of dissolved salts in a reverse osmosis membrane device is generally extremely high (99.3 to 99.7).
%) Is not completely removed, and the total carbonic acid (including carbon dioxide, bicarbonate and carbonic acid) present in a large amount in the raw water is a weak acid, so its removal rate is relatively low (4
0-80%).

For this reason, it is inevitable that the total carbonic acid concentration of the water to be treated at the outlet of the electric deionizer rises. As a result, a large amount of total carbonic acid remains in the treated water and the specific resistance of the treated water decreases. There was a problem that would.

Further, in recent electric deionizers,
2. Description of the Related Art It has been practiced to install a circulation pump to circulate water flowing into a concentration chamber, thereby reducing the amount of water used in the concentration chamber and increasing the recovery rate of ion components. As a result, the ion concentration of the concentrating chamber water is concentrated to about 10 times, the hardness component is also high, and a hardness scale is easily generated on the concentrating chamber side.

When a hardness scale is generated in the electric deionization apparatus, it is necessary to pass a strong acid through the concentration chamber and dissolve the scale substance with the strong acid to remove the hardness scale.

However, excessive cleaning of the ion exchange membrane by a strong acid causes deterioration of the membrane, and when the apparatus is stopped and cleaned, the production efficiency of pure water is reduced. Although it is possible to carry out the washing without stopping the electric deionization apparatus, it is inevitable that the quality of the treated water during the washing deteriorates.

Further, performing acid cleaning every time a scale is generated requires a great deal of labor for daily operation management, which is a very troublesome task for an administrator, and has a problem that productivity is impaired. .

Japanese Patent Application Laid-Open No. 2-40221 discloses a vacuum deaeration tower for converting carbon dioxide in the water to be treated into bicarbonate ions to improve the efficiency of removing total carbon dioxide by an electric deionizer. A technique for installing a pretreatment means such as a decarbonation tower and a membrane deaerator is disclosed.

However, none of these deaerators has a sufficient total carbon dioxide removal rate, and therefore, there is a problem that the effect of preventing the hardness scale of the concentration chamber of the electric deionizer cannot be sufficiently obtained. In addition, vacuum degassing tower,
A pretreatment means such as a decarbonation tower or a membrane degassing tower has a problem that a large installation space is required.

Further, the effect of removing carbonic acid by these devices greatly fluctuates according to the fluctuation of the pH of the water to be treated, and there is also a problem that pH adjustment may be required to enhance the effect.

Incidentally, Japanese Patent Application Laid-Open No. Hei.
A method of adding an alkali to the water to be treated in order to increase the removal rate of total carbon dioxide in the electric deionization apparatus has also been disclosed. However, by merely adding the alkali, the ion load of the electric deionization apparatus is reduced. On the contrary, there is a big problem that a hardness scale is easily generated.

[0016]

As described above, in order to reduce the total carbonic acid in the treated water of the electric deionization apparatus in which the reverse osmosis membrane device is arranged at the preceding stage and to prevent the generation of the hardness scale, the reverse osmosis membrane is required. An apparatus for removing carbon dioxide gas may be provided at the preceding stage of the apparatus, but a method for removing total carbon dioxide, such as a vacuum degassing tower, a decarbonation tower or a membrane degassing apparatus disclosed in Japanese Patent Application Laid-Open No. 40221/1990. All of the apparatuses have a problem that the total carbon dioxide removal rate is not sufficient, and therefore, it is insufficient to prevent the hardness scale of the concentration chamber of the electric deionization apparatus.

In addition to installing these devices, a large installation space is required, and the effect of removing carbon dioxide fluctuates greatly due to fluctuations in the pH of the water to be treated. To enhance the effect, it is necessary to adjust the pH. There was also a problem that there were cases.

The present invention has been made to solve such a problem, and has a sufficient effect of preventing the hardness scale of the concentration chamber of the electric deionization apparatus, having a sufficient total carbon dioxide removal rate, and a small installation space. It is an object of the present invention to provide a pure water production apparatus capable of stably obtaining ultrapure water of extremely high water quality without a great change in effect due to a change in pH of the water to be treated.

[0019]

According to a first aspect of the present invention, there is provided a pure water producing apparatus, comprising: a reverse osmosis membrane device; and a means for decarboxylation using a strongly basic anion exchange resin installed at a stage subsequent to the reverse osmosis membrane device. An electric deionization device disposed downstream of the means for decarboxylation with the strongly basic anion exchange resin.

The strongly basic anion exchange resin used in the present invention can remove all the carbonic acid not removed by the reverse osmosis membrane device with high efficiency, and reduces the anion load in the subsequent electric deionization device. This has the effect of reducing and increasing the specific resistance of the treated water.

Further, the reduction of total carbonic acid is effective in preventing a hardness scale in the concentration chamber of the electric deionization apparatus,
Strongly basic anion exchange resins require less installation space than decarbonation means such as decarbonation towers, vacuum degassing towers, or membrane degassing towers, and their effects vary greatly due to fluctuations in the pH of the water to be treated. Nor.

According to a second aspect of the present invention, there is provided the pure water producing apparatus according to the first aspect, wherein an alkali addition means is provided downstream of the reverse osmosis membrane apparatus and upstream of the means for decarboxylating with a strongly basic anion exchange resin. It is characterized by comprising.

The carbon dioxide, bicarbonate ion and carbonate ion in the total carbonic acid are in an equilibrium state as shown in the formula (I).

Embedded image The equilibrium shifts to the right as the pH of the water to be treated increases, and therefore, the total carbonic acid ion component increases due to the addition of the alkali, and is easily removed by the strongly basic anion exchange resin.

When the strongly basic anion exchange resin is of the OH type, carbon dioxide can also be directly removed by the formula (II). Even in the case of decarboxylation, a high total carbon dioxide removal rate can be obtained.

On the other hand, a strong basic anion exchange resin of 100% Cl type can adsorb only bicarbonate ions and carbonate ions, but increases the pH of the water to be treated by adding an alkali ( By shifting the equilibrium of the formula I) to the right, even a strong basic anion exchange resin of Cl type 100% can eventually remove carbon dioxide.

The alkali to be added is not particularly limited.
aOH, KOH, such as NH ₄ OH can be used.

In the case of mixing OH type and Cl type, alkali addition is basically not necessary since there is an OH type.
The alkali may be added as required, for example, due to fluctuations in the temperature.

[0028] The pure water production apparatus according to the third aspect is the first aspect.
Or the pure water production apparatus according to 2, further comprising a hardness component removing means using a weakly acidic cation exchange resin or a Na-type strongly acidic cation exchange resin before the electric deionization apparatus. I do.

The pure water producing apparatus according to claim 1 or 2 can also provide a sufficient hardness scale prevention effect. However, when the concentration of the hardness component is relatively large due to a difference in the quality of raw water components and the like, this effect can be obtained. Before the electric deionizer, the hardness component removing means using a weakly acidic cation exchange resin or a strongly acidic cation exchange resin of the Na type is arranged to remove the hardness component which causes the other scale formation. By doing so, the effect of preventing the hardness scale can be ensured. Incidentally, these hardness component removing means, depending on the quality of the water to be treated and the water flow conditions, can be used once installed without requiring replacement or regeneration of the resin for at least one year. In addition, the effect of preventing hardness scale can be ensured without significantly increasing equipment costs and maintenance costs.

According to a fourth aspect of the present invention, in the pure water producing apparatus according to any one of the first to third aspects, the strongly basic anion exchange resin is a mixture of Cl type and H type. And the mixture has a Cl-to-H-form exchange capacity ratio of 97 to 80: 3 to 20 in molar ratio.

As the strongly basic anion exchange resin, there are Cl type and OH type resins depending on the difference in the regenerating chemicals. OH
The strong basic anion exchange resin of the type can also remove carbon dioxide that cannot be removed by the strong basic anion exchange resin of the Cl type due to the difference in ion exchange selectivity, and the removal rate in total carbonic acid can be increased. On the other hand, on the other hand, Cl or silica, which cannot be captured by a Cl-type strongly basic anion exchange resin, is also ion-exchanged, so that the frequency of regeneration of the ion exchange resin becomes extremely high.

For this reason, as the strongly basic anion exchange resin used in the present invention, the use of a strongly basic anion exchange resin in which Cl type and OH type are mixed can reduce the ion load of the ion exchange resin. Are suitable. Such a C
A mixture of the l-type and OH-type strongly basic anion exchange resins is
This is effective in reducing the elution of all carbonic acid components from the resin after regeneration and increasing the exchange capacity.

The ratio of Cl type to OH type depends on the ratio of ionic species dissolved in the water to be treated.
The exchange capacity ratio of the OH type is 97-80: 3-2 in equivalent ratio.
0, preferably 95 to 85: 5 to 15, more preferably about 90:10. By setting the existence ratio of the Cl type and the OH type to such a ratio, the regeneration frequency of the strongly basic anion exchange resin can be minimized under the condition that the effect of adsorbing all the carbonic acid components is the maximum.

In general, the strongly basic anion exchange resin is
A NaCl solution is used to regenerate to the l-type and a Na0H solution is used to regenerate to the OH-type. However, other salt solutions may be used to regenerate the strong basic anion exchange resin of the present invention. Yes, it is not necessarily limited to this method.

Strongly basic anion exchange resin of Cl type and OH
In order to obtain a mixture in which the strongly basic anion exchange resin of the type is mixed at a desired ratio, a mixed aqueous solution in which Na0H and NaCl are dissolved at a ratio corresponding to each ratio is used as the regenerating solution ( U.S. Pat. No. 2,855,36
No. 3). That is, the ion exchange capacity is 90% OH type, 1
The strongly basic anion exchange resin of the 0% Cl type is obtained by regenerating the strongly basic anion exchange resin with an aqueous solution containing Na0H and NaCl at a molar ratio of about 9: 1.

According to a fifth aspect of the present invention, in the pure water producing apparatus according to any one of the first to fourth aspects, the electric deionization apparatus has a means for passing the anode water to the concentration chamber. It is characterized by.

It is known that the concentration chamber of the electric deionization apparatus is rich in nutrients for microorganisms, so that microorganisms are likely to be generated depending on the quality of raw water. This tendency to generate microorganisms, as well as the hardness scale, is more prominent in recent high concentration electrodeionization systems that circulate concentrated water. As described above, when microorganisms are generated on the concentration side of the electric deionization apparatus, the electric resistance between the anode and the cathode increases as in the case of the hardness scale, the flow rate on the concentration side decreases, and finally the quality of the treated water also decreases. Problem arises. In the pure water production apparatus of the present invention, TOC components, nutrients for microorganisms such as phosphoric acid and nitric acid are removed by the strongly basic anion exchange resin, and OH ions are eliminated in the OH type strongly basic anion exchange resin. Since the pH becomes alkaline, which is unsuitable for the propagation of microorganisms, the environment is such that microorganisms are less likely to propagate than conventional electrodeionization devices.

In the case where a Cl-type strongly basic anion exchange resin is used in the present invention, a part or all of the anolyte water is periodically or constantly discharged without draining the anolyte water containing a large amount of active chlorine. By mixing with water sent to the concentration chamber, the generation of microorganisms can be more completely prevented, or the generated microorganisms can be sterilized.

That is, in an electric deionization apparatus using a Cl-type strongly basic anion exchange resin, a large amount of active chlorine is generated at the anode, so that the outlet water of the anode water contains a large amount of active chlorine. I do. In particular, 1
In an electric deionization apparatus having a structure in which the concentrated water is circulated between the concentration chamber and the anode chamber by using a means for passing the concentrated water concentrated about 0 times to the anode chamber, the outlet water of the anode chamber is used. The active chlorine concentration will be very high. By passing the anode water having a high active chlorine concentration through the concentration chamber, it is possible to prevent microorganisms from growing in the concentration chamber and prevent water quality deterioration caused by the microorganisms.

Since the anode water has a strong sterilizing effect, it can be widely used for water injection into a raw water tank and other uses for sterilization, in addition to the concentration chamber.

According to a sixth aspect of the present invention, there is provided the pure water producing apparatus according to the fifth aspect of the present invention, further comprising a means for passing the anode water to the concentration chamber through the oxygen removing means.

When the anode chamber water is used, oxygen, which is one of the conditions for breeding microorganisms, is dissolved in the anode water together with the active chlorine. Therefore, in order to ensure aseptic conditions, the anode water uses dissolved oxygen. It is desirable to supply it to the concentration chamber after treating it with oxygen removing means for removal.

As described above, when the anode water is passed through the concentration chamber through the oxygen removing means, when the concentrated water is collected and returned to the preceding stage, for example, before the reverse osmosis membrane device, This is advantageous because the excess oxygen load can be reduced in advance.

According to a seventh aspect of the present invention, there is provided the pure water producing apparatus according to the sixth aspect, wherein the oxygen removing means comprises a catalyst resin in which at least a part of a strongly basic anion exchange resin carries a catalytic metal. It is a means for mixing cathode water with the anode water below. Since the cathode water contains hydrogen, when mixed with the anode water in the presence of the catalytic metal, the hydrogen in the cathode water reacts with the oxygen in the anode water to form water and reduce dissolved oxygen. What is necessary is just to have a deoxygenation function as a catalyst resin. The metal to be carried is not particularly limited, and examples thereof include noble metals such as Cu and Pd.

The pure water producing apparatus according to the eighth aspect is the pure water producing apparatus according to any one of the first to seventh aspects, wherein the oxygen removing means is provided before the means for decarboxylating with the strong basic anion exchange resin. Characterized in that a vacuum deaeration tower or a membrane deaerator is installed.

By disposing a vacuum deaerator or a membrane deaerator as an oxygen removing means before the means for decarboxylating with a strongly basic anion exchange resin, the water to be treated in the electric deionizer is dissolved. Since oxygen is removed and carbon dioxide can be reduced at the same time, the ionic load of the decarboxylation means can be reduced.

According to a ninth aspect of the present invention, in the pure water production apparatus according to any one of the first to eighth aspects, a decarbonation tower is provided before the means for decarboxylation with a strongly basic anion exchange resin. It is characterized by being installed. The decarbonation tower may be installed before the reverse osmosis membrane device.

By installing the decarbonation tower, the carbon dioxide of the water to be treated is reduced, and the ionic load of the decarbonation means can be reduced.

[0049]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following embodiments, the same reference numerals indicate the same devices.

Embodiment 1 FIG. 1 is a system diagram of an embodiment of a pure water producing apparatus according to the present invention. In the apparatus of this embodiment, a reverse osmosis membrane device 1, a decarboxylation device 2 made of a strongly basic anion exchange resin, and an electric deionization device 3 are sequentially arranged along the flow of the water to be treated. It is configured. The strongly basic anion exchange resin of this example is 100% OH type.

Example 2 In the configuration of FIG. 1, Na was used as a strong basic anion exchange resin.
The ratio between the mold and the OH mold was 90:10.

Embodiment 3 FIG. 2 is a system diagram of another embodiment of the pure water producing apparatus of the present invention. In the apparatus of this embodiment, a reverse osmosis membrane device 1, a decarboxylation device 2 made of a strongly basic anion exchange resin, and an electric deionization device 3 are sequentially arranged along the flow of the water to be treated. This is the same as the apparatus of FIG. 1 except that an alkali addition means 4 for injecting an alkali such as a caustic soda solution is arranged between the reverse osmosis membrane apparatus 1 and the decarboxylation apparatus 2 to provide a strong base. Decarboxylation device 2 made of conductive anion exchange resin
The pH of the water to be treated supplied to is maintained on the alkaline side. For the injection amount of the alkali, for example, a pH meter for measuring the pH of the inlet water is installed at the inlet of the decarbonation device 2,
A constant pH value is maintained by feedback control based on the measurement result of the meter.

As the strongly basic anion exchange resin of this example, a resin having a Cl type of 100% was used.

Embodiment 4 FIG. 3 is a system diagram of still another embodiment of the pure water producing apparatus of the present invention. The apparatus of this embodiment includes a reverse osmosis membrane apparatus 1 and a hardness component removing means 5 using, for example, a weakly acidic cation exchange resin.
And decarboxylation device 2 made of strong basic anion exchange resin
And the electric deionizer 3 are sequentially arranged along the flow of the water to be treated.

The hardness component removing means 5 may be made of a Na type strongly acidic cation exchange resin instead of the weakly acidic cation exchange resin. Further, in this embodiment, the hardness component removing means 5 is installed before the decarbonation device 2, but may be installed before the electric deionization device 3 or before the reverse osmosis membrane device 1. Good. That is, the hardness component removing means 5 is for removing a hardness component from the inlet water of the electric deionization device 3 and can be installed at any position before the electric deionization device 3. It is.

Embodiment 5 FIG. 4 is a system diagram of still another embodiment of the pure water producing apparatus of the present invention. The apparatus of this embodiment is the same as the apparatus for producing pure water shown in FIG. 4 except that a vacuum degassing tower 6 is disposed between the hardness component removing means 5 and the decarbonation apparatus 2.

The vacuum degassing tower 6 is for removing all carbon dioxide and reducing the carbon dioxide in the decarbonation apparatus 2.
It can be replaced by a decarbonation tower or a membrane deaerator.

Since the vacuum degassing tower 6 removes dissolved oxygen in addition to carbon dioxide, it has an effect of suppressing the generation of microorganisms in the concentration chamber of the electric deionization apparatus 2.

(Experimental example) Using the apparatus of the above embodiment,
Treated Imizu, Atsugi City, Kanagawa Prefecture. The equipment used and the water flow conditions are as follows.

Reverse osmosis membrane device: SU-710 (manufactured by Toray) Decarboxylation means: Duolite A-116 Type II strong basic anion exchange resin Made

(Comparative Example) As a comparative example, the same processing as in Example 1 was performed using the apparatus shown in FIG. In the comparative example, the other apparatus configuration and processing conditions were the same as those of the example except that the decarbonation apparatus 2 was omitted from the apparatus of the example.

Table 1 shows the processing results of Examples 1 to 5 and Comparative Example.

[0063]

[Table 1]

As is clear from Table 1, in the example using the present invention, the amount of reduction of the total carbon dioxide load in the supply water was larger than that of the comparative example.・ Water with high specific resistance is obtained in treated water. Also, in comparison between the examples, Example 1 has a large number of times of resin regeneration, and Example 3 has a slightly reduced ultimate resistivity.
It turns out that Example 5 is optimal.

Table 2 shows the change in the specific resistance of the electric deionization apparatus / treated water when the apparatuses according to Examples 1 to 5 and the comparative example were continuously operated for 6 months.

[0066]

[Table 2]

In the comparative example of Table 2, five acid washings were required about once a month to remove the hardness scale generated in the electric deionization / concentration chamber. In the case of No, generation of a hardness scale was not recognized, and it was not necessary to perform acid cleaning. Further, in the comparative example, the treatment water quality in the electric deionization apparatus tended to decrease, whereas in the apparatus of the example, the treatment water quality hardly decreased. In addition, in comparison between the examples,
It is understood that the most preferable result is obtained in Example 5.

[0068]

As described above in detail, according to the pure water producing apparatus of the present invention, sufficient decarboxylation is performed by using a strongly basic anion exchange resin. Pure water of extremely high quality can be obtained.

In addition, since the occurrence of a hardness scale in the conventional electric deionizer can be prevented, stable processing can be performed.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of a pure water production apparatus according to the present invention.

FIG. 2 is a system diagram showing another embodiment of the pure water producing apparatus according to the present invention.

FIG. 3 is a system diagram showing another embodiment of the pure water producing apparatus according to the present invention.

FIG. 4 is a system diagram showing another embodiment of the pure water producing apparatus according to the present invention.

FIG. 5 is a system diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reverse osmosis membrane device 2 ... Decarbonation device 3 ... Electric deionization device 4 ... Alkali addition means 5 ... Hardness removal means 6 ... Vacuum deaeration tower

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Fumitaka Yagi 2-9-8 Okada, Atsugi-shi, Kanagawa F-term in Nomura Micro Science Co., Ltd. 4D006 GA03 KA71 KA72 KB11 PB25 PB26 PC02 4D025 AA04 AB16 AB19 BA08 BA10 BA14 BA16 CA05 CA10 DA01 DA05 DA06 DA10 4D061 DA10 DB14 EA09 EB13 ED13 FA03 FA08 FA09

Claims (9)

[Claims] 1. A reverse osmosis membrane device, means for decarboxylation by a strongly basic anion exchange resin installed at a stage subsequent to the reverse osmosis membrane device, and means for decarboxylation by the strong basic anion exchange resin A pure water production apparatus, comprising: an electric deionization apparatus disposed at a subsequent stage. 2. The method according to claim 1, further comprising an alkali addition means in a stage subsequent to the reverse osmosis membrane device and in a stage preceding the means for decarboxylation with the strong basic anion exchange resin.
The pure water production apparatus according to the above. 3. The apparatus according to claim 1, further comprising a hardness component removing means using a weakly acidic cation exchange resin or a Na-type strongly acidic cation exchange resin before the electric deionization apparatus. Or the pure water production apparatus according to 2. 4. The strongly basic anion exchange resin is a mixture of Cl type and OH type, and the mixture has a Cl type: OH type exchange capacity ratio of 97 to 80: 3 to 20 in equivalent ratio. The pure water production apparatus according to any one of claims 1 to 3, wherein 5. The electric deionization apparatus according to claim 1, further comprising means for passing anode water to a concentration chamber.
The pure water production apparatus according to any one of claims 1 to 4. 6. The pure water production apparatus according to claim 5, further comprising means for passing the anode water to a concentration chamber through an oxygen removing means. 7. The oxygen removing means is a means for mixing cathodic water with the anodic water in the presence of a catalytic resin having a catalytic metal supported on at least a part of a strongly basic anion exchange resin. The pure water production apparatus according to claim 6. 8. A vacuum degassing tower or a membrane degassing device as an oxygen removing means is provided before the means for decarboxylating with the strongly basic anion exchange resin.
8. The pure water production apparatus according to any one of claims 1 to 7. 9. The apparatus for producing pure water according to claim 1, wherein a decarbonation tower is provided before the means for decarboxylation with the strong basic anion exchange resin.