Nuclear medicine radioactive waste liquid deep purification unit and application method

Abstract

The invention discloses a nuclear medicine radioactive waste liquid deep purification unit and an application method. The nuclear medicine radioactive waste liquid deep purification unit comprises a deep purification module constructed by n serial short ion exchange columns, the liquid collecting tank 1 and the liquid collecting tank II are respectively arranged at the front liquid inlet end and the rear liquid inlet end of the deep purification module; wherein the liquid inlets of all the short ion exchange columns are respectively connected with the liquid collecting tank 1, the liquid outlets of all the short ion exchange columns are respectively connected with the liquid collecting tank II, and the liquid inlets and the liquid outlets of all the short ion exchange columns are respectively connected with one another through valves; and the liquid outlets and the liquid inlets of the adjacent short ion exchange columns are connected through valves. According to the nuclear medicine radioactive waste liquid deep purification unit and the application method, the nuclear medicine radioactive waste liquid deep purification unit is designed on the basis of the short ion exchange column with the small height-diameter ratio, and disturbance of the purification capacity and waste of exchange fibers or resin caused by replacement of the ion exchange column can be reduced; meanwhile, the replaced new ion exchange column can be always positioned at the tail end, so that the purification efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear medicine radioactive material processing, and more specifically, to a nuclear medicine radioactive waste liquid deep purification unit. Background Art

[0002] The use of ion exchange column technology to treat nuclear medicine radioactive wastewater can speed up its discharge and alleviate the contradiction of limiting the number of patients treated in nuclear medicine due to the untimely discharge of nuclear medicine radioactive wastewater. At present, the ion exchange column used in the deep purification unit of nuclear medicine radioactive wastewater is a long column with a height-to-diameter ratio greater than 1. The time difference between the fibers or resins in the upper and lower parts of this ion exchange column reaching saturation is often relatively long. In this process, the ion exchange capacity of the ion exchange column gradually decreases until it is completely saturated and becomes zero. It can be seen that the ion exchange capacity of the long ion exchange column decays greatly from the initial use with the strongest exchange capacity to the end with the weakest exchange capacity, so the replacement of the long and short ion exchange columns will cause a large fluctuation in the purification performance of the deep purification unit. In order to reduce this fluctuation, the long ion exchange column may be replaced before the exchange capacity reaches saturation, resulting in a waste of ion exchange fibers or resins. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages of the present invention, a nuclear medicine radioactive waste liquid deep purification unit is provided, comprising:

[0005] A deep purification module constructed of n short ion exchange columns in series;

[0006] Two liquid collecting tanks I and II are respectively arranged at the front end and the rear end of the deep purification module;

[0007] Among them, the liquid inlets of all the short ion exchange columns are connected to the liquid collecting tank I through the matching pipeline I respectively;

[0008] The liquid outlets of all the short ion exchange columns are connected to the liquid collecting tank II through the matching pipeline II;

[0009] The liquid inlet and liquid outlet of all short ion exchange columns are connected through pipeline III;

[0010] The liquid outlet and liquid inlet of the adjacent short ion exchange column are connected through pipeline IV;

[0011] Each of the pipelines is respectively provided with a corresponding solenoid valve;

[0012] The outer surfaces of each short ion exchange column and each liquid collecting tank are provided with a lead shielding layer.

[0013] Preferably, each level of short ion exchange columns is arranged in a transverse arrangement, and each level of short ion exchange columns is provided with a detection channel I which runs transversely through the column from the upper part to the center;

[0014] The liquid collecting tank I and the liquid collecting tank II are provided with a detection channel II which runs horizontally through the tank body from the middle to the center;

[0015] Wherein, each detection channel is provided with a corresponding radiation detector.

[0016] Preferably, the liquid inlet and the liquid outlet of each short ion exchange column are arranged on the same side.

[0017] A method for applying a nuclear medicine radioactive waste liquid deep purification unit, comprising:

[0018] S1. When the supernatant to be purified in the liquid collecting tank I is full, the supernatant to be purified is transported to the deep purification module;

[0019] S2. When the supernatant to be purified enters the short ion exchange column in sequence, the radiation detector arranged in the detection channel I monitors the radioactivity data I of the short ion exchange column in real time and transmits it back to the host computer;

[0020] S3. The host computer evaluates the ion exchange capacity of the short ion exchange column based on the m radioactive data I received within the predetermined time node to determine whether to replace or add the short ion exchange column by switching the state of the solenoid valves on pipeline I and pipeline II.

[0021] Preferably, the radioactive data II before and after purification are respectively monitored in real time by the liquid collecting tank I and the liquid collecting tank II, and transmitted back to the host computer;

[0022] The host computer evaluates whether the purified liquid meets the emission requirements based on the received radioactivity data II, and conducts a comprehensive evaluation of the dynamic performance of the deep purification unit.

[0023] The present invention includes at least the following beneficial effects: the present invention is a nuclear medicine radioactive waste liquid deep purification unit designed based on a short ion exchange column with a relatively small height-to-diameter ratio, which can reduce the disturbance of purification capacity caused by replacing the short ion exchange column and the waste of exchange fibers or resins.

[0024] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the composition of the deep purification unit of the present invention;

[0026] Figure 2This is a graph showing the results of the pertechnetate adsorption experiment in Application Example 1;

[0027] Figure 3 This is the result diagram of the adsorption of pertechnetate in the real low-level waste liquid from the nuclear medicine production end in Application Example 2;

[0028] Figure 4 This is the result diagram of the removal rate of pertechnetate in the real low-level waste liquid from the nuclear medicine production end in Application Example 2;

[0029] Figure 5 This is a structural diagram of the self-supporting molecular cage P-RCC6 in Example 1. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0031] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0032] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the term is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "Ⅰ" and "Ⅱ" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] like Figure 1 As shown, the deep purification unit of the present invention comprises: n (n>1) serially connected short ion exchange columns 1 (n is represented by L1, L2...Ln), n+2 radiation detector groups (including n radiation detectors I2 matched with the short ion exchange columns, radiation detectors II31 arranged in the liquid collecting tank I3, and radiation detectors III41 arranged on the liquid collecting tank II), and two liquid collecting tanks I3 and II4 with completely the same structural volumes, as well as matched connecting pipelines 5 and electromagnetic valve groups 6;

[0035] The connecting pipeline 5 comprises:

[0036] A pipeline Ⅰ50 connecting the liquid inlet of each level of short ion exchange column with the liquid outlet pipe Ⅰ30 of the liquid collecting tank Ⅰ3;

[0037] A pipeline II51 connecting the liquid inlet of the subsequent short ion exchange column with the liquid outlet of the previous short ion exchange column;

[0038] Pipeline III 52 connecting the liquid outlet of each short ion exchange column to the liquid inlet pipe 40 on the liquid collecting tank II;

[0039] Connect the liquid outlet of the last short ion exchange column to the liquid inlet of the first short ion exchange column through pipeline IV53;

[0040] A pipeline V54 connecting pipeline I and pipeline III of the short ion exchange column of this stage;

[0041] The solenoid valve group 6 includes:

[0042] Solenoid valves 611, 612, ..., 61n are provided on pipeline I50;

[0043] Solenoid valve 621, solenoid valve 622, ... solenoid valve 62n-1 provided on pipeline II51;

[0044] A solenoid valve 62n is provided on the pipeline IV53;

[0045] Solenoid valves 631, 632, ..., 63n provided on pipeline V54;

[0046] Solenoid valve 641, solenoid valve 642, ... solenoid valve 64n are arranged on pipeline III52.

[0047] By setting corresponding solenoid valves on different pipelines, the deep purification unit of the equipment has the following functions:

[0048] 1. The working quantity of short ion exchange columns can be freely selected or switched;

[0049] 2. The working state of each short ion exchange column can be freely selected or switched;

[0050] 3. Each short ion exchange column can be freely selected for maintenance (i.e. it can be freely cut in and out) without affecting the work of other short ion exchange columns;

[0051] In actual operation, n (n>1) short ion exchange columns are all sealable columns made of stainless steel and lead shielding layer materials, and the interior is filled with ion exchange fibers or resins as needed. By providing a matching lead shielding layer material on the outer surface of each short ion exchange column, the radiation protection safety of the on-site operators can be ensured when the operators replace or maintain the short ion exchange columns. At the same time, the present invention selects short ion exchange columns for application. Compared with the existing long ion exchange columns, the exchange capacity decays less from the initial use of the ion exchange column with strong adsorption capacity to the end of adsorption saturation. Even if a short ion exchange column that has reached adsorption saturation is replaced, the disturbance to the purification capacity of the purification unit is also small. Since the ion exchange fiber or resin is replaced only after it reaches saturation, the utilization rate of the ion exchange fiber or resin is higher;

[0052] The short ion exchange column is arranged horizontally (can be used to shorten the depth of detection channel I), and a radiation detector hole is arranged on the upper part near the liquid outlet, which runs horizontally through the column to the center to construct detection channel I, and is used to place the 1st to nth radiation detectors. The 1st to nth radiation detectors detect the radioactive parameters L1 to Ln on the upper part of the corresponding short ion exchange column in real time, providing a basis for evaluating the dynamic performance of the short ion exchange column. According to the dynamic performance of each short ion exchange column, when doing maintenance in the later stage, the arrangement position of each short ion exchange column can be selectively replaced, and the ones with weaker adsorption capacity are arranged in front, and the short ion exchange column with the strongest purification capacity is always ensured to be at the end, so as to prevent the adsorbed substances from falling after the adsorption capacity of the short ion exchange column is reduced, affecting the final purification effect.

[0053] Each liquid collecting tank is a sealable tank made of stainless steel and lead shielding material. The radiation detector hole runs horizontally through the tank from the middle to the center to construct detection channel II, which is used to place the n+1 and n+2 radiation detectors. The n+1 and n+2 radiation detectors detect the radioactive parameters Ln+1 and Ln+2 of the separation liquid before and after purification in real time, providing a basis for evaluating the purification capacity of the deep purification unit for radioactive wastewater.

[0054] The main function of the deep purification unit of the present invention is to use a short ion exchange column to perform ion exchange on the nuclides in the clear liquid after solid-liquid separation to achieve the purpose of extracting and removing the nuclides in the clear liquid. Compared with the prior art, the short ion exchange column based on the relatively small height-diameter ratio can reduce the impact of the replacement of the short ion exchange column on the purification performance fluctuation of the deep purification unit, prevent the replacement of the short ion exchange column before the exchange capacity reaches saturation, and reduce waste.

[0055] A method for applying a nuclear medicine radioactive waste liquid deep purification unit, comprising:

[0056] S1. When the supernatant to be purified in the liquid collecting tank I is full, the supernatant to be purified is transported to the deep purification module;

[0057] S2. When the supernatant to be purified enters the short ion exchange column in sequence, the radiation detector arranged in the detection channel I monitors the radioactivity data I of the short ion exchange column in real time and transmits it back to the host computer;

[0058] S3. The host computer evaluates the ion exchange capacity of the short ion exchange column based on the m radioactive data I received within the predetermined time node to determine whether to replace or add the short ion exchange column by switching the state of the solenoid valves on pipeline I and pipeline II.

[0059] Specifically, assuming that the measured value of the radioactive parameter at the top of the first short ion exchange column is L1, and the measured values ​​at m evenly distributed time points are L11, L12...L1m, if these m measured values ​​remain large and tend to be consistent, it can be said that the lipid exchange capacity of the fiber or resin at the top of the ion exchange has reached saturation. Because the inlet of the short ion exchange column is at the bottom and the outlet is at the top, that is to say, the fiber or resin at the bottom of the short ion exchange column first contacts the strongest radioactivity of the separation liquid, and the ion exchange reaction is the strongest. As the height increases, the ion exchange reaction gradually weakens. Therefore, if the exchange capacity of the fiber or resin at the top of the ion exchange column reaches saturation, the fiber or resin capacity of the entire short ion exchange column reaches saturation. Compared with the long short ion exchange column with the same inner diameter, the time difference between the upper and lower fibers or resins reaching saturation is shorter, and the ion exchange capacity decays less from the initial use with the strongest exchange capacity to the end with the weakest exchange capacity. Therefore, the replacement frequency of the short ion exchange column is greater than that of the long short ion exchange column. Even if the short ion exchange column is replaced only when it is completely saturated, the disturbance of purification performance caused is small, and the waste of ion exchange fibers or resins is avoided.

[0060] Similarly, by recording and comparing the measured values ​​of a short ion exchange column in a period of time, the exchange capacity of the fiber or resin in the corresponding short ion exchange column can be evaluated, providing a basis for replacing the fiber or resin in the short ion exchange column. The ion exchange capacity is evaluated based on the m measured values ​​of the 1st to nth radiation detectors in a period of time, and the dynamic performance table of the short ion exchange column is obtained as shown in Table 2.

[0061] Table 2

[0062] Measurements Exchange Capacity Working Mode Application Scenario L11《L12《…《L1m powerful normal Short ion exchange column 1 initial use L11<L12<…<L1m generally normal Short ion exchange column 1 mid-term use L11≈L12≈…≈L1m weak abnormal Short ion exchange column 1 End of use / replacement L21《L22《…《L2m powerful normal Short ion exchange column 2 initial use L21 <L22<…<L2m generally normal Short ion exchange column 2 mid-term use L21≈L22≈…≈L2m weak abnormal Short ion exchange column 2 end of use / replacement … … … … Ln1《Ln2《…《Lnm powerful normal Short ion exchange column n initial use Ln1 <Ln2<…<Lnm generally normal Short ion exchange column n mid-term use Ln1≈Ln2≈…≈Lnm weak abnormal Short ion exchange column n end of use / replacement

[0063] Through the above analysis, n new short ion exchange columns are activated at the same time, and the short ion exchange column at the front reaches saturation first and is replaced. In order to ensure the dynamic performance of the deep purification unit, the position of the short ion exchange column is determined according to the size of L1, L2...Ln. The larger the position, the closer it is to the front, so the new column is moved to the back. Under the condition that solenoid valve 631, solenoid valve 632...solenoid valve 63n are all closed, the order of the columns can be changed by opening and closing other solenoid valves, and the replacement order table of short ion exchange columns as shown in Table 3 is obtained.

[0064] Table 3

[0065]

[0066] By opening any one or more of the solenoid valves 631, 632, ..., 63n separately, the short ion exchange columns corresponding to the solenoid valves can be disabled or enabled, which facilitates the addition, reduction or maintenance of the short ion exchange columns according to purification requirements.

[0067] Furthermore, the radioactive data II before and after purification are monitored in real time through the liquid collecting tank I and the liquid collecting tank II, respectively, and transmitted back to the host computer; the host computer evaluates whether the purified liquid meets the emission requirements based on the received radioactive data II, and comprehensively evaluates the dynamic performance of the short ion exchange column. Specifically, it is assumed that the removal rate of the nuclide by the purification device is represented by K = Ln + 1 / Ln + 2, and K0 is the threshold value of the minimum purification capacity. The purification capacity is evaluated according to the measurement values ​​of the n+1 and n+2 radiation detectors, and the dynamic performance table of the deep purification unit is obtained as shown in Table 1.

[0068] Table 1

[0069]

[0070] Furthermore, the short ion exchange column of the present invention uses a self-supporting polymer cage adsorption material to absorb extremely low concentration TcO4 in complex wastewater of nuclear medicine. - Precise removal;

[0071] The self-supporting molecular cage adsorption material has a structural formula as shown in the following formula I:

[0072]

[0073] Wherein, n is an integer from 1 to 8; X - Represents Cl - Br - ,I - 、NO3 - PF6 - Z is one or a combination of CH, N.

[0074] The self-supporting polymer cage adsorption material is a porous ionic polymer material formed by a quaternization reaction between a porous organic molecular cage and a dihalogenated alkane. The structural formulas of the porous organic molecular cage and the dihalogenated alkane are shown in Formula II and Formula III, respectively:

[0075]

[0076] Wherein, n is an integer of 1 to 8, R is F, Cl, Br or I; and Z is one or a combination of CH and N.

[0077] Example 1

[0078] A method for preparing a self-supporting molecular cage adsorption material, the specific steps are as follows:

[0079] S1. Add 20 mL of methanol solvent to 1.025 g (2.63 mmol) of 1,3,5-tri(4-formylphenyl)benzene and 0.402 g (3.94 mmol) of 1,5-diaminopentane, respectively, and slowly drop 1,5-diaminopentane into 1,3,5-tri(4-formylphenyl)benzene. Place the mixed solution in a ventilated place and react at room temperature for 24 h. Filter, wash and dry the obtained solid product to obtain the CC6 imine molecular cage product.

[0080] S2. Dissolve 0.5 g (0.51 mmol) CC6 in 25 mL of a mixed solvent of dichloromethane and methanol (v / v = 1 / 1), add 0.5 g (3.50 mmol) sodium borohydride (NaBH4) under vigorous stirring, and react the mixed solution at room temperature for 15 h. Subsequently, add 1 mL of deionized water as a solvent and continue to react at room temperature for 9 h. The obtained solid product can be filtered, washed, and dried to obtain the reduced RCC6 molecular cage product.

[0081] S3, 2.0g (2.02mmol) of RCC6 was dissolved in 30mL of ethyl acetate, and 1.39g (6.05mmol) of 1,5-dibromopentane (RCC6: 1,5-dibromopentane = 1:3) was added under stirring, and the mixed solution was reacted at 60°C for 32h. The obtained solid product was filtered, washed, and dried to obtain a self-supporting polymer cage P-RCC6 product, whose structure is as follows: Figure 5 shown.

[0082] Application Example 1

[0083] A self-supporting polymer cage adsorption material is used to simulate the removal of pertechnetate in wastewater. The specific steps are as follows:

[0084] Sodium pertechnetate was prepared into a 100 ppm aqueous solution, and the adsorption capacity of the P-RCC6 polymer cage adsorbent prepared in Example 1 was tested. 20 mg of P-RCC6 adsorbent was weighed, 50 mL of sodium pertechnetate aqueous solution (100 ppm) was added, and the adsorption experiment was carried out at pH = 7 and temperature of 25°C and stirred for 12 hours. The concentration of pertechnetate in the solution before and after adsorption was measured.

[0085] Figure 2 The results of the pertechnetate adsorption experiment in Application Example 1. As shown in the figure, the concentration of pertechnetate in the solution was measured to be 0.36 mg / L, and the removal rate of pertechnetate in the water sample by the adsorbent was calculated to be 99.7%. At the same time, two commercial ion exchange materials were selected for the same adsorption experiment, and it was found that the removal efficiency of P-RCC6 was much higher than that of conventional ion exchange materials.

[0086] Application Example 2

[0087] A self-supporting polymer cage adsorption material is used to remove pertechnetate in real low-level wastewater. The specific steps are as follows:

[0088] 20 mg of the P-RCC6 polymolecular cage adsorption material prepared in Example 1 was added to 50 mL of real radioactive wastewater containing pertechnetate ions generated in the nuclear medicine production process (sourced from a nuclear medicine production company, with an initial activity of total α=121.7 Bq / L, total β=5392 Bq / L, pH=6.8), and the adsorption experiment was carried out at a temperature of 25°C and stirred for 12 hours. The total α and total β of the radioactivity concentration in the solution before and after adsorption were measured.

[0089] Figure 3 and Figure 4 This is the adsorption experimental result of pertechnetate in real low-level waste liquid from nuclear medicine production in Application Example 2. As shown in the figure, the total α in the solution after adsorption is measured to be 0.178Bq / L, and the total β is 8.025Bq / L. The removal rate of pertechnetate in wastewater by the adsorbent is calculated to be total α=99.86%, and total β=99.85%.

[0090] The above solution is only an illustration of a preferred embodiment, but is not limited thereto. When implementing the present invention, appropriate replacement and / or modification can be performed according to user needs.

[0091] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A nuclear medicine radioactive waste liquid deep purification unit, characterized in that: include: A deep purification module constructed of n short ion exchange columns in series; Two liquid collecting tanks I and II are respectively arranged at the front end and the rear end of the deep purification module; Among them, the liquid inlets of all the short ion exchange columns are connected to the liquid collecting tank I through the matching pipeline I respectively; The liquid outlets of all the short ion exchange columns are connected to the liquid collecting tank II through the matching pipeline II; The liquid inlet and liquid outlet of all short ion exchange columns are connected through pipeline III; The liquid outlet and liquid inlet of the adjacent short ion exchange column are connected through pipeline IV; Each pipeline is provided with a corresponding solenoid valve; The outer surfaces of each short ion exchange column and each liquid collecting tank are provided with a lead shielding layer.

2. The nuclear medicine radioactive waste liquid deep purification unit according to claim 1, characterized in that: Each level of short ion exchange columns is arranged horizontally, and each level of short ion exchange columns is provided with a detection channel I which runs horizontally through the column from the upper part to the center; The liquid collecting tank I and the liquid collecting tank II are provided with a detection channel II which runs horizontally through the tank body from the middle to the center; Wherein, each detection channel is provided with a corresponding radiation detector.

3. The nuclear medicine radioactive waste liquid deep purification unit according to claim 1, characterized in that: The liquid inlet and the liquid outlet of each short ion exchange column are arranged on the same side.

4. A method for using the nuclear medicine radioactive waste liquid deep purification unit according to any one of claims 1 to 3, characterized in that: include: S1. When the supernatant to be purified in the liquid collecting tank I is full, the supernatant to be purified is transported to the deep purification module; S2. When the supernatant to be purified enters the short ion exchange column in sequence, the radiation detector arranged in the detection channel I monitors the radioactivity data I of the short ion exchange column in real time and transmits it back to the host computer; S3. The host computer evaluates the ion exchange capacity of the short ion exchange column based on the m radioactive data I received within the predetermined time node to determine whether to replace or add the short ion exchange column by switching the state of the solenoid valves on pipeline I and pipeline II.

5. The application method of the nuclear medicine radioactive waste liquid deep purification unit as claimed in claim 4, characterized in that: The radioactive data II before and after purification are monitored in real time through the liquid collecting tank I and the liquid collecting tank II, and transmitted back to the host computer; The host computer evaluates whether the purified liquid meets the emission requirements based on the received radioactivity data II, and conducts a comprehensive evaluation of the dynamic performance of the short ion exchange column.

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