CN117672582B

CN117672582B - Nuclear medicine radioactive wastewater deep purification treatment system and application method

Info

Publication number: CN117672582B
Application number: CN202311032889.7A
Authority: CN
Inventors: 聂小琴; 李小安; 潘宁; 董发勤; 刘家乐; 朱秋红; 陈正国; 刘畅; 刘成; 马春彦
Original assignee: Southwest University of Science and Technology; Mianyang Central Hospital
Current assignee: Southwest University of Science and Technology; Mianyang Central Hospital
Priority date: 2023-08-16
Filing date: 2023-08-16
Publication date: 2024-05-17
Anticipated expiration: 2043-08-16
Also published as: CN117672582A

Abstract

The invention discloses a nuclear medicine radioactive wastewater deep purification treatment system and an application method thereof, wherein the nuclear medicine radioactive wastewater deep purification treatment system comprises the following steps: a waste water collection unit; an ion exchange type rapid deep purification unit; an on-line monitoring unit; a control unit; the rapid deep purification unit comprises at least two sets of ion exchange adsorber modules, each set of ion exchange adsorber module comprises at least two stages of ion exchange adsorbers, and each stage of ion exchange adsorber is switched in series and in parallel through a matched pipeline I and an executing mechanism I on the pipeline I; and each set of ion exchange adsorber module realizes serial and parallel switching through a matched pipeline II and an executing mechanism II on the pipeline II. The invention provides a deep purification treatment system and an application method of nuclear medical radioactive wastewater, which not only realize the rapid and effective removal of total radionuclides of the nuclear medical radioactive wastewater, but also realize the timely discharge of a treated water sample without long-time decay storage treatment.

Description

Nuclear medicine radioactive wastewater deep purification treatment system and application method

Technical Field

The invention relates to the field of radioactive wastewater treatment. More particularly, the invention relates to a nuclear medicine radioactive wastewater deep purification treatment system and an application method thereof.

Background

The treatment of nuclear medicine radioactive wastewater in engineering generally adopts a treatment method stored in a decay tank, and comprises two steps of a continuous decay tank and an intermittent decay tank. The storage time spent using a decay cell to treat nuclear medicine radioactive wastewater is closely related to the radioisotope with the longest half-life contained in the cell. For example: for radioactive wastewater containing I-131 (with half-life of 8.03 days), the storage time is not less than 80 days, and the radioactive wastewater is required to be allowed to be discharged to a conventional sewage treatment station of a hospital and then discharged to a municipal sewage network until the radioactive activity concentration of the wastewater is attenuated below a specified value. The existing nuclear medicine radioactive wastewater purification treatment process is innovated on the basis of a decay tank. Such as: patent CN115223741a invented a radioactive waste water treatment system and treatment method, which performs differential screening on radioactive waste water of nuclear medicine department, and performs separation treatment on low-radioactivity waste water, and by setting a high-radioactivity decay tank and a low-radioactivity object decay tank, the utilization efficiency and working efficiency of the traditional decay tank are further improved.

The traditional decay tank treatment method stores a large amount of radioactive wastewater for a long time according to the storage time with at least 10 half-lives, so that the decay tank has larger volume, large occupied area, high manufacturing cost and very low wastewater treatment efficiency, and the established decay tank is difficult to expand to meet the requirement of increasing the number of the consultations.

In summary, the conventional treatment method does not consider the volume reduction treatment of the nuclear medicine radioactive wastewater. The emission standard of water pollutants in medical institutions in China (GB 1866-2005) prescribes that the total alpha of emission port monitoring values of radioactive sewage treatment facilities is less than 1Bq/L and the total beta is less than 10Bq/L. Therefore, a new method and a new process for deeply purifying the radioactive waste water in nuclear medicine are needed, and the radioactive waste water of the type is subjected to rapid deep purification treatment, so that the radioactive waste water meets the waste minimization requirement, the waste water treatment efficiency is improved, the diagnosis and treatment quantity in nuclear medicine department is met, and meanwhile, the radioactivity level of a radioactive waste water discharge port in nuclear medicine is ensured to meet the standard requirement of a sewage discharge limit value and is timely discharged to a conventional waste water pipe network in a hospital.

Disclosure of Invention

It is an object of the present invention to address at least the above problems and/or disadvantages and to provide at least the advantages described below.

To achieve these objects and other advantages and in accordance with the purpose of the invention, there is provided a nuclear medicine radioactive wastewater deep purification treatment system, comprising:

a waste water collection unit for storing nuclear medicine radioactive waste water;

an ion exchange type rapid deep purification unit communicated with the wastewater collection unit;

The on-line monitoring unit is used for detecting the total alpha and total beta radioactivity concentration of the stock solution and the output solution of the rapid deep purification unit in real time;

The control unit is in communication connection with the rapid deep purification unit and the on-line monitoring unit;

The rapid deep purification unit comprises at least two sets of ion exchange adsorber modules, each set of ion exchange adsorber module comprises at least two stages of ion exchange adsorbers, and each stage of ion exchange adsorber is switched in series and in parallel through a matched pipeline I and an executing mechanism I on the pipeline I;

and each set of ion exchange adsorber module realizes serial and parallel switching through a matched pipeline II and an executing mechanism II on the pipeline II.

Preferably, the on-line monitoring unit includes: the device is arranged at the outlet end of the stock solution and each ion exchange adsorber so as to detect the total alpha and the total beta of the output solution in real time;

Wherein, the outlet end of each ion exchange absorber is respectively communicated with the inlet end of the lower ion exchange absorber and the purified water tank;

the inlet end of each ion exchange adsorber is communicated with the wastewater collection unit.

Preferably, when the ion exchange adsorber modules are connected in parallel, the ion exchange adsorber modules are ready for use.

Preferably, each stage of the ion exchange adsorber is configured to include:

One end of the adsorber shell made of glass fiber reinforced plastic is provided with a water inlet, and the other end is provided with a water outlet;

the water inlet end plate is arranged at the water inlet side through a stop block;

A handle end plate arranged at the water outlet side through a thrust ring;

The nuclide deep purification filter element is arranged in the adsorber shell in a direct plug-in mode;

wherein, both ends of the absorber shell are connected with the pipeline in a hoop connection mode;

the nuclide deep purification filter element is filled with at least one functional material with strong extraction and exchange on medical radionuclides.

Preferably, the adsorber shell is further provided with a side opening mouth at one side close to the water outlet.

An application method of a nuclear medicine radioactive wastewater deep purification treatment system comprises the following steps:

Firstly, storing nuclear medical radioactive wastewater by adopting a wastewater collection unit, and collecting radioactive level data of a stock solution by a control unit;

step two, the stock solution flows into a rapid deep purification unit through a liquid inlet pump so as to carry out deep purification treatment on the stock solution through ion exchange to remove radionuclides;

And thirdly, detecting the purified liquid treated by the first-stage ion exchange adsorber in the rapid deep purification unit through an online monitoring unit, and performing radioactivity analysis and test through a control unit. The control unit determines whether the emission standard limit value of the national regulation is met according to the test result, and the emission standard limit value is discharged to a conventional sewage pipe network of a hospital, or the non-standard purified liquid is returned to the next stage of ion exchange adsorber of the rapid deep purification unit for further deep purification treatment until the radioactivity level of the purified liquid meets the emission standard limit value of the national regulation;

when the radioactivity analysis test is carried out on the purifying liquid, the control unit is used for carrying out the total radioactivity concentration test, test data collection and record on the purifying liquid.

Preferably, in the second step, when the ion exchange adsorber modules of the rapid deep purification unit are in a parallel connection state, the treatment process stage number is set to be two-stage adsorption, and the purification treatment process route is switched to the three-stage and four-stage ion exchange adsorbers connected in parallel only when the first-stage and the second-stage ion exchange adsorbers reach 2.96×10 ⁶ Bq/kg. During the use of the three-stage and four-stage ion exchange adsorbers, the primary and secondary ion exchange adsorbers do not need to be operated at all and only undergo spontaneous decay. And after the decay is completed, the ion exchange adsorption device is continuously used, and the two ion exchange adsorber modules are sequentially switched to be used until the first-stage ion exchange adsorber and the second-stage ion exchange adsorber are saturated in nuclide adsorption. After the saturated ion exchange adsorber filter element is subjected to radioactive decay until reaching the standard, the filter element is subjected to regeneration treatment through a regeneration detergent so that the filter element can be continuously and repeatedly adsorbed;

the regenerated detergent is configured to adopt at least one of sodium chloride, potassium chloride, dilute hydrochloric acid and ammonium chloride.

Preferably, the failure determination of the ion exchange adsorber needs to satisfy the following conditions simultaneously:

The method comprises the steps that firstly, the activities of a wastewater stock solution and a purified solution are detected based on an online detection unit to obtain corresponding radioactivity concentration values, and a corresponding calculated purification coefficient is considered to meet the first condition if the activity concentration values are smaller than a set value;

And a second condition, wherein the preset service life of the ion exchange adsorber is given based on the test and theoretical calculation, and if the service life is longer than the preset service life, the second condition is considered to be satisfied.

Preferably, the control unit realizes automatic hierarchical control through a PLC program control system arranged on the control unit, and the PLC program control system comprises a plurality of functional modules of data acquisition, process control, alarm prompt, alarm record and an operable interface;

the data acquisition means that the control unit performs timing acquisition on the total alpha and total beta activity concentration data through communication among the online monitoring units;

The process control means that the control unit switches the serial or parallel state between each ion exchange adsorber or each set of ion exchange adsorber modules based on the radioactivity analysis test to finish the start and stop control of each ion exchange adsorber;

the operable interface receives the setting of the operation parameters through the control unit and displays the corresponding detection parameters, alarm prompts and alarm records.

Preferably, after the online monitoring unit detects the total alpha and total beta radioactivity concentration of the stock solution in real time, the control unit selectively manages the working state of the executing mechanism at the input end of each ion exchange adsorber based on the total alpha and total beta radioactivity concentration values so as to determine the number of stages of ion exchange adsorbers into which the stock solution can flow for adsorption treatment;

after the on-line monitoring unit detects the total alpha and total beta radioactivity concentration of the output liquid of each stage of ion exchange adsorber in real time, the control unit selectively manages the working state of the executing mechanism at the output end of each ion exchange adsorber based on the total alpha and total beta radioactivity concentration values of each stage of ion exchange adsorber so as to determine whether the output liquid can flow into the purified water tank.

The invention at least comprises the following beneficial effects: the invention aims to solve the problem of low treatment efficiency of nuclear medical radioactive wastewater by a decay tank method, and provides a deep purification treatment system which has the advantages of low cost, high efficiency, high safety, long service time, flexibility and variability and can be used for real nuclear medical radioactive wastewater. Meanwhile, by using the process method of the treatment system, not only is the total radionuclide in the nuclear medical radioactive wastewater rapidly and effectively removed, but also the water sample after treatment is discharged in time, and long-time decay storage treatment is not needed.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 is a schematic diagram of a process route of a nuclear medicine radioactive wastewater deep purification treatment system in one embodiment of the present invention;

FIG. 2 is a block diagram of a nuclear medicine radioactive wastewater deep purification treatment system in accordance with one embodiment of the present invention;

FIG. 3 is a side view of the water inlet side of an ion exchange adsorber in accordance with one embodiment of the invention;

FIG. 4 is a side view of an ion exchange adsorber in accordance with one embodiment of the invention from another perspective;

FIG. 5 is a side view of the water side of an ion exchange adsorber in accordance with one embodiment of the invention;

FIG. 6 is a side view of an ion exchange adsorber in accordance with one embodiment of the invention from another perspective on the water outlet side;

FIG. 7 is a full spectrum of X-ray photoelectron spectra before and after iodine ion adsorption by Ag/RGO-1 in one embodiment of the invention

FIG. 8 is a graph showing the penetration of a dynamic adsorption column using an Ag/RGO-1 adsorbent material on a simulated radioactive wastewater containing iodide in an embodiment of the present invention.

Detailed Description

The present invention is described in further detail below with reference to the drawings to enable those skilled in the art to practice the invention by referring to the description.

It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

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 are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "provided," "engaged/connected," "connected," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, may be a detachable connection, or may be an integral connection, may be a mechanical connection, may be an electrical connection, may be a direct connection, may be an indirect connection via an intermediary, may be a communication between two elements, and for one of ordinary skill in the art, the specific meaning of the terms in this disclosure may be understood in a specific case.

The invention provides a nuclear medicine radioactive wastewater deep purification treatment system and a treatment method (or called treatment process). The treatment system consists of an ion exchange rapid deep purification treatment unit, an on-line monitoring unit and a control unit, and the technical route diagram of the treatment method is shown in figure 1.

1) The nuclear medicine radioactive waste water is firstly stored by adopting a waste water collecting unit (a liquid container also comprising a conventional decay tank), the container is made of polyethylene, and the receiving nuclear medicine radioactive waste water comprises excrement generated by a patient in the process of radioactive medicine diagnosis and treatment, a medicine cup used by the patient and cleaning water generated during split charging of the radioactive isotope medicine, and is a mixed solution containing one or more nuclides. The radioisotope types include: i-131, I-125, tc-99m, F-18, etc. Then pumping the ion exchange rapid deep purification treatment unit through a pipeline.

2) The ion exchange rapid deep purification unit consists of a plurality of ion exchange adsorbers and has the functions of realizing the enrichment of radionuclides in the wastewater and realizing the radioactive removal of the wastewater. As shown in FIG. 2, the deep purification unit consists of two sets of two-stage series adsorbers which are mutually standby in parallel, and total 4 adsorbers. And the inlets of the two sets of devices are communicated with a waste water storage container pipeline, the outlet of each adsorber is communicated with a purified water tank, the waste water is discharged into a conventional sewage tank of a hospital after the total radioactivity level of the on-line monitoring reaches the standard, otherwise, the purified liquid is returned to the next-stage adsorber to continue the deep purification treatment until the detection is qualified. When the method is operated, the first-stage absorber is used, if the purifying liquid does not reach the standard, the purifying liquid flows through the second-stage absorber again, and so on or the waste water flows through the first-stage absorber and the second-stage absorber in series in sequence (the condition that the initial activity of the waste water is higher or the waste water amount is large), and when the radioactivity level of one set of the second-stage absorbers reaches the higher limit value of the low-level radioactive waste, the other set of absorbers is started. At this point, the previous set of adsorbers allowed to spontaneously decay and continued to be used after the decay is complete. The two sets of adsorbers are subjected to repeated alternate switching operation, so that the method is suitable for a long-term non-replacement action plan, and direct contact between personnel and radioactive waste is avoided. And after the adsorber fails, the operation of replacing the adsorber is performed without stopping the adsorber. The adsorber adopts a nuclide deep purification filter element structure, the filter element is installed in a fast-assembling structure, and the adsorption material is replaced by directly plugging the filter element. The inlets and outlets of the ion exchange adsorbers are communicated, the inlets and the outlets are connected in a high-pressure hoop connection mode, the adsorbers at all stages can be switched between any series connection and parallel connection, electromagnetic valves are arranged, and an automatic control system is used for operating the on-off state. The adsorber has compact structure and small occupied area, and can ensure high-performance adsorption and simultaneously realize the later-stage replacement of the adsorption filter element. The ion exchange adsorber is filled with high-density functional materials which have strong extraction and exchange for medical radionuclides. The functional material is at least one of strong alkalinity, weak alkalinity, strong acidity, weak acidity, chelate type functional ion exchange fiber, resin and other adsorption materials. The waste filter element is used as radioactive solid waste for concentrated storage treatment, washing and regeneration treatment are carried out after the radioactivity level is reduced to a safe value, and the filter element can be reused for a plurality of times. The regenerated detergent is at least one of sodium chloride, potassium chloride, dilute hydrochloric acid and ammonium chloride.

Further, as shown in fig. 3-6, each stage of ion exchange adsorbers is configured to include:

The adsorber shell 1 made of glass fiber reinforced plastic is provided with a water inlet 14 at one end and a water outlet 15 at the other end, wherein the water outlet and the water inlet are used for being connected with pipelines laid on site, so that different serial or parallel layout effects are constructed on site through valves arranged on the pipelines, and meanwhile, the adsorber shell can be more easily installed and detached through modularized arrangement, and a side water outlet 13 is arranged on the adsorber shell through a side water outlet pipe 12 according to actual requirements on site;

The water inlet end plate 5 is arranged at the water inlet side through the stop block 4, the stop block is fixedly connected with the water inlet end plate through the stop block bolt 2 and the spring gasket 3 so as to ensure the stability of the cooperation between structures, and the water inlet end plate has the functions of connecting a water inlet pipeline, distributing water to an adsorption material, sealing and fixing the adsorption material and controlling the water inlet flow;

The handle end plate 8 is arranged on the water outlet side through the thrust ring 6, and a corresponding sealing ring 7 is arranged at a matched position of the inner side wall of the adsorber shell so as to ensure the tightness of the adsorber shell. The handle end plate has the advantages that the filter element is convenient to install and detach, the adsorption material is fixed safely, and the handle end plate is sealed and connected with a water inlet and outlet pipeline;

the nuclide deep purification filter element is arranged in the adsorber shell in a direct plug-in mode, and the filter element structure is adopted to enable the filter element to be easily taken out and replaced when the filter element cannot achieve the effect in the later period;

wherein, adsorber shell both ends all are connected with the pipeline through the connected mode of staple bolt. In this kind of structure, can realize the quick connect of ion exchange adsorber and corresponding pipeline through the connected mode of staple bolt, realize quick assembly and disassembly, and as required the staple bolt is configured to include: the binding belt 9 matched with the outer structure of the absorber shell and the saddle 11 matched with the binding belt connect the binding belt and the saddle into an integrated structure to complete the binding belt bolt 10 of the ion exchange absorber and the corresponding pipeline. Wherein, the saddle is provided with the arc on with adsorber shell matched with lateral wall and prescribes a limit to the groove to guarantee that laminating degree between the structure satisfies the installation requirement.

The automatic control unit adopts hierarchical control, is equipped with automatic control of a PLC program control system, and performs data acquisition, process control, alarm prompt, alarm recording and operation interface functions. The data acquisition is connected with the radioactivity online monitoring system to acquire the total alpha and total beta activity concentration data at regular time. The process control function is used for switching the adsorbers in series and parallel and controlling the selective start and stop of each adsorber. The operation interface function is used for setting operation parameters, and comprises the following steps: waste water flow, alarm threshold value and test data record.

A schematic flow chart of the application of the nuclear medicine radioactive wastewater deep purification treatment system is shown in fig. 2.

Nuclear medicine radioactive wastewater generated in the production and use processes of radioactive isotopes in nuclear medicine department is temporarily stored in a nuclear medicine radioactive wastewater temporary storage tank; then, the wastewater enters a first-stage ion exchange deep purification absorber at a constant flow rate by means of a liquid inlet pump, the purified liquid after the first-stage ion exchange is subjected to on-line monitoring on the radioactivity concentration, and the purified liquid meeting the radioactivity emission requirement is discharged into a conventional hospital sewage tank; otherwise, the control unit controls the purifying liquid to enter the next stage of ion exchange purifying treatment until reaching the discharge standard. The ion exchange rapid deep purification unit has the best process stage number of four-stage adsorbers, when the primary and secondary ion exchange adsorbers reach the highest limit value of low-level radioactive waste, the deep purification treatment process route is switched to the tertiary and quaternary ion exchange adsorbers, the primary and secondary ion exchange adsorbers are not required to be operated, and the primary and secondary ion exchange adsorbers only undergo spontaneous decay to the background level and then are continuously used. And after the ion exchange absorber fails, the filter element replacement operation is carried out on the failed ion exchange absorber, and the replaced waste filter element is temporarily stored according to the radioactive solid waste treatment requirement.

Replacement of the ion exchange adsorber requires that the following two conditions be met simultaneously: ① Calculating a purification coefficient (total radioactivity before exiting/total radioactivity after treatment) by detecting the activities of the wastewater stock solution and the purification solution, and if the activity is smaller than a set value, satisfying the requirement; ② Experimental experience or theoretical calculation gives the service life of a general ion exchange adsorber, if greater than a set value, then it is satisfied.

The treatment method is a continuous treatment process, the core component of the ion exchange adsorber filter element is replaced after the process pipeline system is not required to be disassembled to stop in the operation process, and only one set of multistage serial adsorbers which are standby are started for one-time operation. When detecting that the ion exchange adsorber of the purifying unit in use reaches the replacement requirement, the purifying unit is quickly switched to another set of standby purifying unit for wastewater treatment, and meanwhile, the ion exchange adsorbing material is quickly replaced by directly inserting and removing the filter element. The specific wastewater treatment process flow comprises the following four steps:

1) Temporary storage: collecting nuclear medical radioactive wastewater in a temporary storage tank, and collecting raw liquid radioactivity level data by a control unit;

2) Ion exchange: flowing the stock solution into an ion exchange adsorber through a pump, performing ion exchange deep purification treatment on the wastewater, removing radionuclides, and performing next radioactivity analysis and test on the obtained purified solution;

3) Radioactivity monitoring: measuring the radioactivity concentration of the purified liquid, and testing, collecting and recording the total radioactivity concentration data by a control unit;

4) And (3) discharging after reaching the standard: if the radioactivity level of the purifying liquid meets the national regulated discharge standard limit value, the total alpha is less than 1Bq/L, the total beta is less than 10Bq/L, and the purifying liquid is discharged into the conventional sewage pipe network of the hospital. And returning the purifying liquid which does not reach the standard to an absorber at the next stage of the ion exchange process for further ion exchange deep purification treatment, measuring the radioactivity concentration after the treatment, and discharging after the value meets the limit value.

The method and the process for deeply purifying the nuclear medicine radioactive wastewater provided by the invention can be used for rapidly and effectively removing radionuclides in the nuclear medicine radioactive wastewater. The total alpha and total beta radioactivity concentration removal rate is not less than 99.29% (total alpha and total beta here mean that the waste water possibly contains a plurality of nuclides and the nuclides have radioactivity to release alpha rays or beta rays, and as the radioactivity concentration values of the total alpha and the total beta are only required when the waste water is discharged up to standard, specific requirements are not set for a certain radionuclide, only the total alpha and the total beta radioactivity concentration change is considered, the treated purifying liquid meets the radioactivity emission standard requirements of water pollutants of medical institutions through total radioactivity concentration analysis, and the whole process is simple and convenient to operate, small in occupied area, short in waste water treatment period (for a decay tank storage method with the capacity of 80m ³, the treatment time is shortened to 25 days from the original 180 days, 8 hours are treated every day), high in working efficiency and automatic control is provided, and waste minimization is realized rapidly.

In general, the present invention provides a set of secondary ion exchange adsorbers with predetermined life values: the total beta=600Bq/L of stock solution, the limit value of low-level radioactive waste is set to 2.96× ⁶ Bq/kg (parallel circuit switching is carried out), the limit value setting is 0.8 times of 3.7× ⁶ Bq/kg, the filling amount of the single-stage ion exchange adsorber is 35kg, the adsorber reaches 172m ³ of low-level radioactive waste limit treatment waste water, the treatment waste water amount of one set of secondary ion exchange adsorbers is 344m ³, the operation time of one set of secondary ion exchange adsorbers is half year, then the in-situ setting decay is carried out, the decay time is half year, and then the operation is continued. Taking I-131 as an example, according to the saturated adsorption capacity of the material to iodine of 2000mg/kg, the actual adsorption capacity of the material to iodine ions per year of 2.96 multiplied by 10 ⁶ Bq/kg (equivalent to 0.6 ng/kg), the theoretical value of the preset service life value is long, and the service life of the initially designed single ion exchange adsorber is 20-50 years.

Further, each set of two-stage ion exchange adsorbers can be set into four stages, each stage is respectively communicated with the output end of the previous wastewater collection unit through an actuating mechanism (the actuating mechanism is a mechanism or a combination of mechanisms for controlling the pipeline communication state, such as an electromagnetic valve and a flow valve), and is communicated with the inlet end of the subsequent lower-stage ion exchange adsorber and the purified water tank, so that each set of two-stage ion exchange adsorbers can adopt several stages of ion exchange adsorbers for treatment according to concentration, and the two-stage ion exchange adsorbers adopt the pre-stage treatment or the post-stage treatment, and the wastewater after the treatment is finished can directly flow out to the purified water tank according to requirements, and the method has better applicability, and specifically comprises the following treatment modes:

After the online monitoring unit detects the total alpha and total beta radioactivity concentration of the stock solution in real time, the control unit selectively manages the working state of the executing mechanism at the input end of each ion exchange adsorber based on the total alpha and total beta radioactivity concentration values so as to determine the number of stages of ion exchange adsorbers into which the stock solution can flow for adsorption treatment;

Example 1

A nuclear medical radioactive wastewater deep purification treatment method and process comprises the following steps:

1) Temporary storage: the volume of the nuclear medical radioactive wastewater in the temporary storage tank is 2.5L, the total alpha=1.548 Bq/L and the total beta= 620.657Bq/L;

2) Ion exchange: the wastewater sequentially flows through a primary ion exchange adsorber and a secondary ion exchange adsorber (two-stage series mode) through a peristaltic pump at the flow rate of 11.7mL/min, and 20g of weak base type ion exchange fibers are filled in a single adsorber;

3) Radioactivity monitoring: measuring the radioactivity concentration of the purified liquid;

4) And (3) discharging after reaching the standard: the radioactivity level of the purifying liquid meets the national regulated emission standard limit, and the actual value is total alpha=0.005 Bq/L and total beta=0.311 Bq/L.

For this embodiment, the processing cycle is: 3.56h.

Comparative example: for total alpha=1.548 Bq/L, total beta= 620.657Bq/L, and volume of 2.5L of nuclear therapeutic radioactive wastewater, the prior art adopts a decay tank for storage for at least 48 days, and the wastewater is allowed to be discharged.

Example 2

1) Temporary storage: the volume of the nuclear medical radioactive wastewater in the temporary storage tank is 2m ³, the total alpha=1.276 Bq/L and the total beta=1000 Bq/L;

2) Ion exchange: the wastewater sequentially flows through a primary ion exchange adsorber and a secondary ion exchange adsorber (two-stage series mode) through a peristaltic pump at the flow rate of 400L/h, and 35kg of weak base type ion exchange fibers are filled in a single adsorber;

4) And (3) discharging after reaching the standard: the radioactivity level of the purifying liquid meets the national regulated emission standard limit, and the actual value is total alpha=0.019 Bq/L and total beta= 0.659Bq/L.

For this embodiment, the processing cycle is: 5h.

Comparative example: for total α=1.276 Bq/L, total β=1000 Bq/L, and a volume of 2m ³, the prior art uses a decay tank to store for at least 54 days (typically 180 days) before allowing the waste water to drain.

Compared with the prior art, the method can realize rapid deep purification treatment of the radioactive wastewater, can ensure that the radioactive wastewater meets the waste minimization requirement, effectively improves the wastewater treatment efficiency and the treatment capacity, meets the diagnosis and treatment quantity of nuclear medicine department, and simultaneously ensures that the radioactivity level of the radioactive wastewater discharge port of the nuclear medicine meets the standard requirement of the sewage discharge limit value and is discharged to the conventional wastewater pipe network of a hospital in time.

Example 3

The adsorption functional material (aiming at radioactive iodine) for nuclear medical radioactive wastewater treatment comprises the following components: the nanometer Ag functionalized graphene, the Ag-polypyrrole composite material, the calcium alginate-silver chloride composite material and the Cu functionalized graphene are preferably adopted as nanometer Ag functionalized graphene (Ag/RGO) adsorption materials in practical application.

The following describes the preparation of a nano Ag functionalized graphene (Ag/RGO) adsorption material used in the treatment of nuclear medicine radioactive wastewater (iodine-containing wastewater):

The preparation of the Ag/RGO adsorption material adopts graphene oxide and silver nitrate as raw materials, sodium borohydride as a reducing agent and adopts a one-step method of silver ion adsorption and in-situ reduction to prepare the target adsorption material Ag/RGO, and the specific method comprises the following steps: firstly, weighing 0.1 g-0.4 g of graphene oxide, mixing with 200mL of deionized water, and performing ultrasonic dispersion in an ultrasonic cleaner with power of 120-480W for 1 hour to prepare a graphene oxide aqueous dispersion with concentration of 2.0 mg/mL. Next, 0.5 to 2mL of concentrated aqueous ammonia was added and stirred for 10 minutes, at which time the dispersion became alkaline. Then 0.0212 g-0.1699 g silver nitrate (0.1 mmol-1 mmol) is added into the alkaline graphene oxide water dispersion and is continuously stirred, so that the graphene oxide is ensured to effectively adsorb silver ions. After stirring for 10min, 50mL of a 0.2mol/L aqueous sodium borohydride solution (0.3783 g,10.0 mmol) was slowly added to the dispersion. Then the reaction vessel is placed in an oil bath pot, the temperature is increased to 80-100 ℃, and the reaction is stirred for 30min under the temperature condition to ensure that the reduction reaction is completed. And next, standing the mixed solution at room temperature for one night, and then carrying out suction filtration, washing and drying, wherein deionized water is adopted to wash a filter cake, and the pH value of the filtrate is 7.0 as a washing end point. Finally, the solid was freeze-dried in a freeze-dryer for 24h, then weighed and bagged, and the product was designated Ag/RGO.

1. Further, optimal preparation conditions

The preparation of the Ag/RGO adsorption material adopts graphene oxide and silver nitrate as raw materials, sodium borohydride as a reducing agent and adopts a one-step method of silver ion adsorption and in-situ reduction to prepare the target adsorption material Ag/RGO, and the specific method comprises the following steps: firstly, 0.4000g of graphene oxide is weighed and mixed with 200mL of deionized water, and the mixture is subjected to ultrasonic dispersion in a 360W power ultrasonic cleaner for 1 hour to prepare a graphene oxide aqueous dispersion with the concentration of 2.0 mg/mL. Next, 1mL of concentrated aqueous ammonia was added and stirred for 10 minutes, at which time the dispersion became alkaline. Then 0.1699g of silver nitrate (1 mmol) was added to the above aqueous alkaline graphene oxide dispersion and stirred continuously to ensure effective adsorption of the silver ions by the graphene oxide. After stirring for 10min, 50mL of a 0.2mol/L aqueous sodium borohydride solution (0.3783 g,10.0 mmol) was slowly added to the dispersion. Then the reaction vessel was placed in an oil bath, the temperature was raised to 90 ℃, and the reaction was stirred at this temperature for 30 minutes to ensure completion of the reduction reaction. And next, standing the mixed solution at room temperature for one night, and then carrying out suction filtration, washing and drying, wherein deionized water is adopted to wash a filter cake, and the pH value of the filtrate is 7.0 as a washing end point. Finally, the solid was freeze-dried in a freeze-dryer for 24 hours, then weighed and bagged, and the product was designated Ag/RGO-1.

In order to illustrate the beneficial effects of the particular adsorbent material of example 3 in the treatment of nuclear medicine radioactive wastewater (iodine-containing wastewater), supplementary descriptions are provided below by way of example 4 and example 5, respectively:

Example 4

1) Temporary storage: the volume of the medical radioactive wastewater with the iodine-containing nuclei is simulated to be 3L, and the initial concentration of I ^- is=8.89 mg/L (0.07 mmol/L);

2) Nuclide adsorption: the wastewater sequentially flows through a first-stage ion exchange adsorber through a peristaltic pump at a flow rate of 3.97mL/min, and 0.1g of Ag/RGO-1 adsorbing material is filled in the adsorber;

3) Iodine ion testing in effluent at different moments: measuring the concentration of iodine ions in the collected purifying liquid;

4) Saturated adsorption capacity calculation: the saturated adsorption capacity of Ag/RGO-1 to iodine ions in water can reach 155mg/g (equivalent to 7.1X10 ¹⁴Bq¹³¹ I/g).

For this embodiment, the processing cycle is: 12.6h.

Comparative example: for low-level waste water total beta=9.87×10 ⁵ Bq/L, nuclear medical radioactive waste water with a volume of 3L (total radioactivity is set to 2.96×10 ⁶ Bq), the prior art adopts a decay tank for storage, and the theoretical storage time is at least 147 days, so that the waste water is allowed to be discharged, and the total beta is less than or equal to 10Bq/L.

In combination with FIG. 7, it can be seen that the presence of iodine element is clearly observed in Ag/RGO-1 after iodine adsorption, indicating that Ag/RGO-1 has excellent adsorption capacity for iodine ions in water. As is clear from the adsorption penetration graph 8, the penetration volume of the Ag/RGO-1 adsorption I ^- can reach 670mL (the concentration of the effluent I ^- is 0.05 times that of the inlet I ^-) for the I ^- with the initial concentration of 8.89mg/L, and the dynamic saturation adsorption capacity can reach 155mg/g.

Example 5

1) Temporary storage: the volume of the nuclear medical radioactive wastewater in the temporary storage tank is 2.5L, the total alpha=0.373 Bq/L and the total beta=600 Bq/L;

2) Nuclide adsorption: the wastewater sequentially flows through a first-stage ion exchange adsorber through a peristaltic pump at a flow rate of 11.7mL/min, and 5g of Ag/RGO-1 adsorbing material is filled in the adsorber;

4) And (3) discharging after reaching the standard: the radioactivity level of the purifying liquid meets the national regulated emission standard limit, and the actual value is total alpha=0.017 Bq/L and total beta=0.494 Bq/L.

For this embodiment, the processing cycle is: 3.56h.

Comparative example: for total α=0.373 Bq/L, total β=600 Bq/L, and a volume of 2.5L of nuclear therapeutic radioactive wastewater, the prior art employs a decay tank for at least 48 days to allow for wastewater discharge.

Example 6

The ion exchange fiber adsorption material in each stage of ion exchange adsorbers can select any one of the following materials according to actual needs:

material 1, quaternary ammonium ion exchange fiber (selected from a number of existing materials, as a preferred example of the invention over existing materials):

The preparation process of the quaternary ammonium type ion exchange fiber comprises the following steps: the preparation of the base fiber, the grafting of the polypropylene fiber with styrene, the chloromethylation and amination of the grafted fiber, in particular, can be subdivided from the following four steps:

Firstly, melt spinning polypropylene master batches, soaking the spun fibers in an acetone solvent for 24 hours, removing the organic solvent, washing with distilled water, cleaning with ultrasonic waves, and drying at 60 ℃ to obtain the polypropylene fibers.

And secondly, grafting reaction. The polypropylene fiber is firstly swelled in dichloroethane, then is soaked in a styrene grafting solution, and is grafted at the temperature of 70-120 ℃, preferably at the temperature of 90 ℃, and the grafting time is 3-8 h, and most preferably 6h. And obtaining the grafted fiber with a certain grafting rate after the reaction is finished.

Third, chloromethylation. A proper amount of zinc chloride catalyst (the weight ratio of the catalyst to the fiber is 1:1) is added into a certain volume of chloromethyl ether, and the mixture is stood for 0.5h at room temperature, so that zinc chloride can be partially dissolved. Then adding a certain amount of grafted styrene fiber, fully soaking the fiber in chloromethyl ether solution, standing for 0.5h at room temperature, then putting the reactor into a water bath kettle, slowly heating to 30-80 ℃, preferably 50 ℃, and reacting for 8-13 h, preferably 10h. Stirring is carried out every 1 hour to ensure that the reaction is more uniform and full.

And fourthly, quaternizing. The fiber after chloromethylation reaction is put into trimethylamine water solution (the mole ratio of the fiber to the trimethylamine is 1:1.05, and the pH=9.0) and reacts for 12-16 hours at the temperature of 20-40 ℃, preferably at the temperature of 30 ℃, and preferably for 14 hours. Stirring every 1h in the reaction process to ensure the sufficiency and uniformity of the reaction.

Material 2, imidazolium cation-functionalized ion-exchange fiber

The imidazolium cation functionalized ion exchange fiber in the example is redesigned according to the actual application scene and application requirement, and the preparation process comprises the following steps: the preparation of the base fiber, the grafting of the polypropylene fiber with styrene, the chloromethylation and amination of the grafted fiber are 4 steps, and in particular, can be subdivided from the following four steps:

And fourthly, quaternizing. The fiber after chloromethylation reaction is put into N-methylimidazole aqueous solution (the mol ratio of the fiber to the N-methylimidazole is 1:0.8-1:1.2, preferably 1:1.05, and the pH=9.0) and reacts for 12-16 hours at the temperature of 20-60 ℃, preferably at the temperature of 40 ℃, and preferably for 14 hours. Stirring every 1h in the reaction process to ensure the sufficiency and uniformity of the reaction.

In the material 2 in this example, compared with the material 1, the material 2 introduces the imidazolium cation, and compared with trimethylamine, the imidazolium cation has a five-membered ring pi conjugated system and an N heteroatom structure, and can show good adsorption effect on iodine and iodine anions through the acting force of the cation pi and halogen bond effect generated by the N heteroatom. Therefore, the material No.2 introduces cation-pi acting force and N heteroatom attractive force on the previous ion exchange machine, and the adsorption capacity of the material to ions is increased.

Material 3, hydroxyl functional quaternary ammonium type ion exchange fiber

The hydroxyl functional quaternary ammonium type ion exchange fiber in the embodiment is redesigned according to the practical application scene and application requirement, and the preparation process comprises the following steps: the preparation of the base fiber, the grafting of the polypropylene fiber with styrene, the chloromethylation and amination of the grafted fiber are 4 steps, and in particular, can be subdivided from the following four steps:

And fourthly, quaternizing. The fiber after chloromethylation reaction is put into 2-dimethylamino ethanol aqueous solution (the mol ratio of the fiber to the 2-dimethylamino ethanol is 1:0.8-1:1.2, preferably 1:1.05, and the pH=9.0) and is reacted for 12-16 hours at the temperature of 20-50 ℃, preferably the temperature is 30 ℃, preferably the time is 14 hours. Stirring every 1h in the reaction process to ensure the sufficiency and uniformity of the reaction.

Compared with the material 1, the material 3 in the example introduces quaternary ammonium cations with hydroxyl functional groups on the basis of keeping the original synthetic reactivity, and the added hydroxyl functional groups can generate strong hydrogen bond interaction with ions to be adsorbed in a water system, so that the adsorption capacity of the No. 3 fiber material on the ions is improved.

The above is merely illustrative of a preferred embodiment, but is not limited thereto. In practicing the present invention, appropriate substitutions and/or modifications may be made according to the needs of the user.

The materials preparation method, the number of equipment and the scale of processing described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be readily apparent to those skilled in the art.

Although embodiments of the invention have been disclosed above, they are not limited to the use listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. Therefore, the invention is not to be limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.

Claims

1. A nuclear medicine radioactive wastewater deep purification treatment system, comprising:

Each set of ion exchange adsorber modules realizes serial and parallel switching through a matched pipeline II and an executing mechanism II on the pipeline II;

the ion fiber exchange adsorption material in each stage of ion exchange adsorber adopts the following ion imidazolium cation functionalized ion exchange fiber:

the preparation process of the imidazolium cation functionalized ion exchange fiber comprises the following steps:

Firstly, melt spinning polypropylene master batches, soaking the spun fibers in an acetone solvent for 24 hours, removing the organic solvent, washing with distilled water, cleaning with ultrasonic waves, and drying at 60 ℃ to obtain polypropylene fibers;

Secondly, a grafting reaction is carried out, namely, firstly, polypropylene fibers are swelled in dichloroethane, then are immersed in a styrene grafting solution, grafting is carried out after the temperature is raised to 70-120 ℃, the grafting time is 3-8 h, and the grafted fibers with a certain grafting rate can be obtained after the reaction is finished;

Thirdly, chloromethylation, namely adding a proper amount of zinc chloride catalyst into a certain volume of chloromethyl ether, standing at room temperature for 0.5h at the weight ratio of the catalyst to the fiber being 1:1, adding a certain amount of grafted styrene fiber, fully soaking the grafted styrene fiber into the chloromethyl ether solution, standing at room temperature for 0.5h, then putting the reactor into a water bath kettle, slowly heating to 30-80 ℃, reacting for 8-13 h, and stirring once every 1h to ensure that the reaction is more uniform and full;

Fourthly, quaternizing, namely placing the fiber subjected to chloromethylation into an N-methylimidazole aqueous solution, wherein the molar ratio of the fiber to the N-methylimidazole is 1:0.8-1:1.2, the pH=9.0, and reacting for 12-16 h at the temperature of 20-60 ℃, and stirring every 1h in the reaction process to ensure the sufficiency and uniformity of the reaction.

2. The nuclear medicine radioactive wastewater deep purification treatment system of claim 1, wherein the on-line monitoring unit comprises: the device is arranged at the outlet end of the stock solution and each ion exchange adsorber so as to detect the total alpha and the total beta of the output solution in real time;

3. The nuclear medicine radioactive wastewater deep purification treatment system of claim 1, wherein when the ion exchange adsorber modules are connected in parallel, the ion exchange adsorber modules are ready for use.

4. The nuclear medicine radioactive wastewater deep purification treatment system of claim 1, wherein each stage of ion exchange adsorbers is configured to include:

A handle end plate arranged at the water outlet side through a thrust ring;

5. The nuclear medicine radioactive wastewater deep purification treatment system of claim 1, wherein the adsorber housing is further provided with a side opening on a side near the water outlet.

6. A method of using the nuclear medicine radioactive wastewater deep purification treatment system of claim 1, comprising:

Detecting the purified liquid processed by the first-stage ion exchange adsorber in the rapid deep purification unit through an online monitoring unit, and performing radioactivity analysis test through a control unit, wherein the control unit determines whether the detected result meets the national specified emission standard limit value according to whether the detected result is discharged into a conventional sewage pipe network of a hospital or returns the purified liquid which does not reach the standard to the next-stage ion exchange adsorber of the rapid deep purification unit for further deep purification until the radioactivity level of the purified liquid meets the national specified emission standard limit value;

7. The method of using a deep purification treatment system for nuclear medicine radioactive wastewater according to claim 6, wherein in the second step, when each set of ion exchange adsorber modules of the rapid deep purification unit are in a parallel state, the treatment process stage is set to be a secondary adsorption, the purification treatment process route is switched to a three-stage ion exchange adsorber and a four-stage ion exchange adsorber connected in parallel only when the first ion exchange adsorber and the second ion exchange adsorber reach 2.96×10 ⁶ Bq/kg, during the use of the three-stage ion exchange adsorber and the four-stage ion exchange adsorber, any operation is not needed to be performed on the first ion exchange adsorber and the second ion exchange adsorber, only spontaneous decay is performed, the two sets of ion exchange adsorber modules are switched to be used in sequence after the decay is completed, until the first ion exchange adsorber and the second ion exchange adsorber are saturated with nuclide adsorption, and after the radioactive decay of the ion exchange adsorber filter element to reach the standard, the filter element is regenerated by a regenerated detergent, so that the filter element can be repeatedly adsorbed continuously;

8. The method for applying a nuclear medicine radioactive wastewater advanced purification treatment system according to claim 7, wherein the failure determination of the ion exchange adsorber is required to satisfy the following conditions simultaneously:

and a second condition, wherein the preset service life of the ion exchange adsorber is given based on experimental and theoretical calculation, and if the service life is longer than the preset service life, the second condition is considered to be satisfied.

9. The application method of the nuclear medicine radioactive wastewater deep purification treatment system according to claim 6, wherein the control unit realizes automatic hierarchical control through a PLC program control system arranged on the control unit, and the PLC program control system comprises a plurality of functional modules of data acquisition, process control, alarm prompt, alarm record and an operable interface;

10. The method of claim 6, wherein the control unit selectively manages the operating states of the actuators at the input ends of the ion exchange adsorbers based on the total α and total β radioactivity concentration values after the online monitoring unit detects the total α and total β radioactivity concentrations of the stock solution in real time, so as to determine to which level of ion exchange adsorbers the stock solution can flow into for adsorption treatment;