Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
  • B01J49/50—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents
  • B01J49/57—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents for anionic exchangers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
  • B01J49/60—Cleaning or rinsing ion-exchange beds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange

Definitions

• the present invention relates to a method for purifying ion exchange resins, an ion exchange device, a water treatment system, and an anion exchange resin.
• a method for regenerating anion exchange resins has been disclosed in which anion exchange resins used in demineralization equipment are contacted with an aqueous mineral acid solution to remove contaminants adhering to the surface of the anion exchange resin, and then the resins are regenerated using an aqueous sodium hydroxide solution (see, for example, Patent Document 1). Also disclosed is a method for reducing the amount of metal impurities contained in a cation exchange resin by contacting the resin with a mineral acid solution (see, for example, Patent Document 2).
• Patent Document 1 is a method for regenerating used anion exchange resin in order to reduce the frequency of anion exchange resin replacement. Therefore, it does not take into consideration improving the quality of treated water when using anion exchange resin before it is packed into an ion exchange device.
• the purpose of the technology described in Patent Document 1 is to return used anion exchange resin to its pre-replacement state, restore the performance of the anion exchange resin, and remove contaminants attached to the anion exchange resin packed into an ion exchange device, but not to remove impurities or leachables from the anion exchange resin before it is packed into an ion exchange device.
• the object of the present invention is to provide an ion exchange resin purification method, an ion exchange device, a water treatment system, and an anion exchange resin that can improve the quality of treated water when using an anion exchange resin.
• the method for purifying an ion exchange resin of the present invention comprises the steps of: contacting an aqueous mineral acid solution with an anion exchange resin prior to being packed into an ion exchange device; and a step of contacting the anion exchange resin that has been contacted with the aqueous mineral acid solution with an alkali metal hydroxide solution having a metal concentration that is equal to or less than a predetermined threshold value.
• the ion exchange device of the present invention further comprises:
• the anion exchange resin packed in the ion exchange device is purified using a purification method for ion exchange resin, which includes a step of contacting an anion exchange resin before being packed in the ion exchange device with an aqueous mineral acid solution, and a step of contacting the anion exchange resin that has been contacted with the aqueous mineral acid solution with an alkali metal hydroxide solution having a metal concentration equal to or less than a predetermined threshold value.
• the water treatment system of the present invention includes: An ion exchange apparatus filled with an anion exchange resin purified using a purification method for an ion exchange resin, which includes the steps of contacting an aqueous mineral acid solution with an anion exchange resin before the resin is filled in the ion exchange apparatus, and contacting the anion exchange resin that has been contacted with the aqueous mineral acid solution with an alkali metal hydroxide solution having a metal concentration equal to or less than a predetermined threshold, is provided in a secondary pure water production system or downstream of the secondary pure water production system.
• the anion exchange resin of the present invention is The anion exchange resin is purified using a purification method that includes a step of contacting an aqueous mineral acid solution with an anion exchange resin before the resin is packed into an ion exchange device, and a step of contacting the anion exchange resin that has been contacted with the aqueous mineral acid solution with an alkali metal hydroxide solution having a metal concentration equal to or less than a predetermined threshold value.
• the quality of treated water can be further improved when anion exchange resin is used.
• FIG. 1 is a flowchart illustrating an example of a method for purifying an ion exchange resin according to the present invention.
• 2 is a flowchart illustrating an example of a method for purifying a CP resin using an intermediate raw material cation exchange resin and an intermediate raw material anion exchange resin purified in the process described using the flowchart shown in FIG. 1 is a graph showing an example of the relationship between the metal concentration of an alkali metal hydroxide solution used in a regeneration process and the amount of metal eluted from a CP resin.
• FIG. 3 is a diagram showing an example of a water treatment system to which the CP resin purified by the process described using the flowchart shown in FIG. 2 is applied.
• FIG. 1 is a flowchart illustrating one example of the method for purifying ion exchange resin of the present invention.
• a raw resin for anion exchange resin and unpurified (unpurified) anion exchange resin are prepared.
• This anion exchange resin is resin before being filled into an ion exchange device.
• Examples of resin before being filled into an ion exchange device include unused resin that has never been filled into an ion exchange device installed in a primary pure water production system or secondary pure water production system (subsystem), and resin that has been filled and used in an ion exchange device installed in a primary pure water production system or secondary pure water production system, then removed from the ion exchange device and regenerated, before being refilled into the ion exchange device.
• Step S1 is a cleaning step using an acid (chemical).
• a predetermined anion exchange resin purification column may be filled with unpurified anion exchange resin, and the mineral acid aqueous solution may be supplied through a first pipe connected to the anion exchange resin purification column.
• an on-off valve may be provided in the first pipe, and the supply of the mineral acid aqueous solution may be controlled by controlling the opening and closing of the on-off valve.
• the mineral acid aqueous solution used in step S1 include hydrochloric acid (HCl), sulfuric acid ( H2SO4 ), and nitric acid ( HNO3 ).
• Step S2 is a regeneration step using alkali.
• the acid (chemical) washing step in step S1 is performed, the ion exchange groups of the anion exchange resin are converted to a salt form. Therefore, the regeneration step in step S2 is performed to return the salt-form ion exchange groups of the anion exchange resin to their usable form.
• the alkali metal hydroxide solution may be supplied through a second pipe connected to an anion exchange resin purification column filled with the anion exchange resin that was contacted with the mineral acid aqueous solution in step S1.
• an on-off valve may be provided on this second pipe, and the supply of the alkali metal hydroxide solution may be controlled by controlling the opening and closing of this on-off valve.
• the alkali metal hydroxide solution used here is an aqueous solution maintained at 25% by weight. This 25% by weight alkali metal hydroxide solution is diluted to a predetermined concentration (e.g., 4% by weight) and contacted with the anion exchange resin.
• the metal concentration of the alkali metal hydroxide solution used here is below a predetermined threshold.
• the metal concentration of this alkali metal hydroxide solution is preferably 200 ⁇ g/L or less when the iron concentration in the alkali metal hydroxide solution is 25 wt%.
• the metal concentration of the alkali metal hydroxide solution is preferably 100 ⁇ g/L or less when the aluminum concentration in the alkali metal hydroxide solution is 25 wt%.
• the quality of the treated water treated using the anion exchange resin can be controlled to a desired value.
• Iron and aluminum exist in anionic form at pH 13 or higher. Therefore, iron and aluminum can adhere to the anion exchange resin during the alkali-based regeneration process in step S2. Therefore, it is desirable to consider the concentration of the alkali metal hydroxide solution used in step S2.
• step S3 the anion exchange resin regenerated in step S2 is washed with ultrapure water (step S3).
• the ultrapure water used for this washing is ultrapure water at room temperature.
• the anion exchange resin washed in this way becomes the purified anion exchange resin to be packed into the CP.
• steps S1 to S3 may be repeated a predetermined number of times.
• examples of other processes include passing an alkaline bicarbonate solution through the system, passing ultrapure water through the system, etc.
• FIG 2 is a flowchart illustrating an example of a method for purifying CP resin using a cation exchange resin intermediate material and an anion exchange resin intermediate material purified using the process described using the flowchart in Figure 1.
• the cation exchange resin used here is an intermediate material purified using a general purification method.
• This cation exchange resin intermediate material may also be an intermediate material purified using the method described in the above-mentioned Patent Document 2 (Patent No. 4,441,472), for example.
• the intermediate raw material cation exchange resin is mixed with the intermediate raw material anion exchange resin purified in the step described using the flowchart in Figure 1 (step S11).
• the resin mixture of cation exchange resin and anion exchange resin is washed with ultrapure water at room temperature (step S12). In this way, the CP resin used in water treatment to produce ultrapure water is purified.
• Figure 3 is a graph showing an example of the relationship between the metal concentration of the alkali metal hydroxide solution used in the regeneration process and the amount of metal eluted from the CP resin.
• the upper graph in Figure 3 shows the relationship between the concentrations of Cases 1 to 3 and the conventional method and the ratio of the amount of aluminum and iron eluted from the 25 wt% alkali metal hydroxide solution to the amount of eluted from the conventional CP resin.
• the concentrations of aluminum and iron contained in the 25 wt% alkali metal hydroxide solutions in Cases 1 to 3 are shown below.
• the 25 wt% alkali metal hydroxide solution is diluted to a predetermined concentration (e.g., 4 wt%) as described above.
• Case 1 Iron concentration 200 ⁇ g/L or less, aluminum concentration 100 ⁇ g/L or lessCase 2: Iron concentration 200 ⁇ g/L or less, aluminum concentration 100 ⁇ g/L or moreCase 3: Iron concentration 200 ⁇ g/L or more, aluminum concentration 100 ⁇ g/L or more
• the bottom diagram in Figure 3 shows an example of the relationship between the metal concentration in a 25 wt% alkali metal hydroxide solution and the ratio of the elution amount to that of a conventional CP resin. The relationship shown in Figure 3 is the result of an experiment.
• the lower the metal concentration in the 25 wt% alkali metal hydroxide solution used in the regeneration process the lower the amount of metal elution in the treated water treated with CP resin.
• the upper diagram of Figure 3 when the iron concentration and aluminum concentration in the 25 wt% alkali metal hydroxide solution used in the regeneration process are both above a predetermined threshold, as in Case 3, the amount of iron elution and aluminum elution in the treated water treated with CP resin are both greater than conventional.
• the amount of aluminum elution in the treated water treated with CP resin is greater than conventional. Also, when the iron concentration and aluminum concentration in the 25 wt% alkali metal hydroxide solution used in the regeneration process are both below a predetermined threshold, as in Case 1, the amount of iron elution and aluminum elution in the treated water treated with CP resin are both less than conventional.
• FIG. 4 shows an example of a water treatment system that uses CP resin purified using the process described using the flowchart in FIG. 2.
• the water treatment system shown in FIG. 4 includes a pretreatment system 10, a primary pure water production system 20, and a secondary pure water production system 30, which is a so-called subsystem.
• the pretreatment system 10 may be a system used in general water treatment systems.
• the pretreatment system 10 is water treatment equipment that removes fine particles from the raw water that is supplied.
• the primary pure water production system 20 is water treatment equipment that performs a specified treatment on the treated water treated in the pretreatment system 10 and supplies the treated water to the secondary pure water production system 30.
• the secondary pure water production system 30 may be a secondary pure water production system used in general water treatment systems.
• the secondary pure water production system 30 is water treatment equipment that removes trace amounts of ions and total organic carbon that could not be completely removed in the primary pure water production system 20.
• the treated water treated in the secondary pure water production system 30 is supplied to the point of use, which is the destination of the treated water.
• the secondary pure water production system 30 is provided with a CP100.
• the CP100 is a water treatment device filled with a mixed bed of anion exchange resin and cation exchange resin purified using the purification method described above.
• the CP100 removes ions from the water to be treated supplied from the UV oxidation device installed upstream.
• the secondary pure water production system 30 is a system that manages the metal concentration in the treated water to be 1 ppt or less.
• the CP100 may also be installed in a system downstream of the secondary pure water production system 30.
• the unpurified anion exchange resin is washed with acid, regenerated with alkali, and washed with ultrapure water. This reduces the metal components contained in the unpurified anion exchange resin.
• This anion exchange resin is then used as the resin to be packed into the secondary pure water production system 30 or the CP100 located downstream thereof. In this case, the anion exchange resin is packed into the CP100 as a mixed bed with a cation exchange resin. This makes it possible to further improve the quality of the ultrapure water supplied from the secondary pure water production system 30. Note that this anion exchange resin may also be used as a single bed.
• Pretreatment system 20 Primary pure water production system 30 Secondary pure water production system 100 CP

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Treatment Of Water By Ion Exchange (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=96920301

Family Applications (1)

Country Status (3)

Citations (8)

• 2025
  • 2025-01-20 WO PCT/JP2025/001593 patent/WO2025182348A1/ja active Pending
  • 2025-01-20 JP JP2026503699A patent/JPWO2025182348A1/ja active Pending
  • 2025-02-21 TW TW114106407A patent/TW202600247A/zh unknown

Patent Citations (8)

Also Published As

Similar Documents

Legal Events