Nickel ion imprinting extraction device and detection method and detection kit thereof

Abstract

The present application relates to the technical field of water quality detection and monitoring, and discloses a nickel ion imprinting extraction device, including a sampling assembly, including a tube and a push-pull rod, the push-pull rod is slidably inserted into the tube, and the tube is provided with a sample outlet and a sample inlet; pulling the push-pull rod can make the fluid enter the tube from the sample inlet, and pushing the push-pull rod can make the fluid in the tube flow out from the sample outlet; a flow passage is formed between the liquid inlet and the liquid outlet of the extraction head, and the liquid inlet is connected to the sample outlet of the tube; a nickel ion imprinting extraction membrane can be covered in the flow passage of the extraction head, so that when the push-pull rod is pushed, the fluid in the tube flows out from the sample outlet to the extraction head and flows through the nickel ion imprinting extraction membrane before flowing out. The nickel ion imprinting extraction device has a simple structure and is easy to operate. It can realize on-site enrichment and extraction of nickel ions in water samples in conjunction with the detection method, and can be mass-produced and reused, which is suitable for promotion and application. The present application also discloses a method and a detection box for detecting nickel ions in water.

Description

Technical Field

[0001] The present application relates to the technical field of water quality detection and monitoring, for example, to a nickel ion imprinting extraction device and a detection method and a detection box thereof. Background Art

[0002] Nickel has a wide range of applications and is often used in electroplating, batteries, and manufacturing industries such as aircraft and radar. Nickel ions can enter the skin through pores and sebaceous glands. Chronic excessive intake or excessive exposure to nickel by humans can lead to degenerative changes in the heart, brain, lungs, etc. The Groundwater Quality Standard (GB / T 14848-2017) lists nickel as a toxicological indicator and stipulates limit standards for various types of water. At present, the detection methods for nickel in water are mainly laboratory indoor detection methods, such as inductively coupled plasma emission spectrometry, inductively coupled plasma mass spectrometry, atomic absorption spectrometry, etc. These methods use large instruments that cannot be carried to the site. Therefore, water samples need to be collected and transported to the laboratory for testing. The detection cycle is long, and water samples are easily interfered by other factors during storage and transportation, affecting the accuracy of the test results.

[0003] In the process of implementing the embodiments of the present disclosure, it was found that there are at least the following problems in the related art: currently, most methods for detecting nickel in water are laboratory indoor detection, which requires sample collection, storage and transportation to the laboratory, with poor timeliness. Moreover, there are many factors that affect the nickel ion concentration during storage and transportation, making it difficult to ensure accuracy. Summary of the invention

[0004] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical components or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0005] The disclosed embodiments provide a nickel ion imprinting extraction device and a detection method and a detection box thereof, so as to solve the problem that most of the current detection methods for nickel in water are laboratory indoor detection with poor timeliness. It can realize on-site sampling and sample preparation, and then realize on-site detection, with a short detection cycle and good timeliness.

[0006] In some embodiments, the nickel ion imprinting extraction device comprises:

[0007] The sampling assembly includes a tube and a push-pull rod, wherein the push-pull rod is slidably inserted into the tube from the first end of the tube, and a sample outlet and a sample inlet are arranged at the second end of the tube; pulling the push-pull rod can make the fluid enter the tube from the sample inlet, and pushing the push-pull rod can make the fluid in the tube flow out from the sample outlet;

[0008] The extraction head is provided with a liquid inlet and a liquid outlet, a flow channel is formed between the liquid inlet and the liquid outlet, and the liquid inlet is connected to the sample outlet of the tube; wherein, the flow channel of the extraction head can be covered with a nickel ion imprinted extraction membrane, so that when the push-pull rod is pushed, the fluid in the tube flows out from the sample outlet to the extraction head and flows through the nickel ion imprinted extraction membrane before flowing out.

[0009] In some embodiments, a method for detecting nickel ions in water comprises:

[0010] Enriching nickel ions in the water sample to be tested: using the aforementioned nickel ion imprinting extraction device, a first preset volume of the water sample to be tested is sucked into the tube through the sample inlet, and then the water sample to be tested is discharged through the sample outlet, thereby enriching the nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane;

[0011] Eluting the nickel ions on the nickel ion imprinted extraction membrane: a second preset volume of eluent is sucked into the tube through the injection port of the nickel ion imprinted extraction device, and then the eluent is discharged through the outlet port, and the eluent elutes the nickel ions on the nickel ion imprinted extraction membrane when flowing through the nickel ion imprinted extraction membrane, and the eluted nickel ions flow out of the tube with the eluent to obtain the eluent;

[0012] Color development and phase change: add the color developer solution and magnesium sulfate solution to the eluent, shake and mix, then add a third preset volume of n-butanol, shake and mix, let stand and separate, and obtain the upper organic phase as the test sample;

[0013] The sample to be tested is subjected to absorbance measurement or colorimetric visual inspection, and the nickel ion mass concentration in the water sample to be tested is determined according to the absorbance-nickel ion mass concentration standard curve or standard colorimetric card / tube.

[0014] In some embodiments, a nickel ion detection kit for water includes: the aforementioned nickel ion imprinting extraction device, which can absorb the water sample to be tested through the sample inlet and then discharge the water sample to be tested through the sample outlet, thereby enriching the nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane; a reagent combination, including an eluent, a color developer solution, a magnesium sulfate solution and n-butanol, the eluent is used to elute the nickel ions enriched on the nickel ion imprinting extraction membrane of the nickel ion imprinting extraction device to obtain an eluent; by sequentially adding the color developer solution, the magnesium sulfate solution and the n-butanol solution to the eluent, a sample to be tested containing nickel ions is obtained.

[0015] The nickel ion imprinted extraction membrane and the device, system and detection method including the same provided in the embodiments of the present disclosure can achieve the following technical effects:

[0016] The nickel ion imprinting extraction device has a simple structure, is convenient for sampling and enriching nickel ions, and is convenient for absorbing eluent and eluting nickel ions, thereby preparing a sample to be tested. It is simple and easy to operate, and can achieve on-site enrichment and extraction of nickel ions in water samples, thereby eliminating the need for water sample collection protection (addition of protective agents), storage and transportation, and effectively avoiding the influence of various factors on the nickel ion concentration in water. Moreover, the nickel ion imprinting extraction device can be mass-produced and reused, and is suitable for promotion and application.

[0017] The nickel ion detection method in water, combined with the nickel ion imprinting extraction device, realizes on-site enrichment and extraction of nickel ions in water samples, and combines on-site detection of the absorbance of the test sample or colorimetric visual method to achieve rapid and accurate determination of the nickel ion content in water. Moreover, trace nickel ions can be detected through enrichment, and the detection limit is reduced.

[0018] The nickel ion detection kit in water, in addition to the nickel ion imprinting extraction device, is also equipped with a reagent combination for the detection process, which is convenient to use. Thus, the on-site rapid detection of nickel ion content in water samples can be achieved.

[0019] In summary, the embodiments of the present disclosure are based on a nickel ion imprinting extraction device to achieve a convenient, fast and low-cost way of obtaining an eluent containing nickel ions, and further combine it with an on-site detection method to achieve a rapid and accurate determination of the nickel ion content in water.

[0020] The embodiments of the present disclosure can be applied to fields involving water quality detection and monitoring, such as water environment detection and water environment restoration and management.

[0021] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein:

[0023] Figure 1 It is a structural schematic diagram of a nickel ion imprinting extraction device provided in an embodiment of the present disclosure;

[0024] Figure 2 is a schematic structural diagram of a sampling assembly provided by an embodiment of the present disclosure;

[0025] Figure 3 is a schematic cross-sectional structural diagram of an extraction head provided in an embodiment of the present disclosure;

[0026] Figure 4 is a schematic diagram of a top view of an extraction head provided by an embodiment of the present disclosure;

[0027] Figure 5 is a structural schematic diagram of a support structure in an extraction head provided by an embodiment of the present disclosure;

[0028] Figure 6 is a schematic cross-sectional view of another support structure of an extraction head provided in an embodiment of the present disclosure;

[0029] Figure 7 It is a schematic diagram of the cross-sectional structure of another extraction head provided in an embodiment of the present disclosure.

[0030] Reference numerals:

[0031] 10: sampling assembly; 11: tube; 110: graduation line; 111: sample outlet; 112: sample inlet; 113: external thread; 12: push-pull rod; 13: sample inlet switch; 130, liquid inlet pipe; 14: sample outlet switch; 20: extraction head; 21: liquid inlet; 22: liquid outlet; 23: flow channel; 231: straight-through section; 232: necking section; 24: supporting structure; 241: supporting rod; 242: inner ring frame; 243: outer ring frame; 30, nickel ion imprinting extraction membrane; 41: heating unit; 42: heating power supply; 43, controller. DETAILED DESCRIPTION

[0032] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0033] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0034] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0035] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0036] Unless otherwise stated, the term "plurality" means two or more.

[0037] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B indicates: A or B.

[0038] The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0040] Combination Figures 1 to 5As shown, the embodiment of the present disclosure provides a nickel ion imprinting extraction device, including: a sampling assembly 10 and an extraction head 20. The sampling assembly 10 includes a tube 11 and a push-pull rod 12, the push-pull rod 12 is slidably inserted into the tube 11 from the first end of the tube 11, and the second end of the tube 11 is provided with a sample outlet 111 and a sample inlet 112; pulling the push-pull rod 12 can make the fluid enter the tube 11 from the sample inlet 112, and pushing the push-pull rod 12 can make the fluid in the tube 11 flow out from the sample outlet 111; that is, when the push-pull rod 12 is pulled, the sample outlet 111 is closed to ensure that the fluid enters the tube 11 from the sample inlet 112, and when the push-pull rod 12 is pushed, the sample inlet 112 is closed to ensure that the fluid only flows out from the sample outlet 111. The extraction head 20 is provided with a liquid inlet 21 and a liquid outlet 22, a flow channel 23 is formed between the liquid inlet 21 and the liquid outlet 22, and the liquid inlet 21 is detachably connected to the sample outlet 111 of the tube 11. The flow channel 23 of the extraction head 20 can be covered with a nickel ion imprinted extraction membrane 30, so that when the push-pull rod 12 is pushed, the fluid in the tube 11 flows out from the sample outlet 111 to the extraction head 20 and flows through the nickel ion imprinted extraction membrane 30 before flowing out.

[0041] In the nickel ion imprinting extraction device of the disclosed embodiment, an inlet 112 and an outlet 111 are simultaneously provided on one end side of the tube 11 of the sampling assembly 10, so that the water sample can flow in and out through different ports, so that the nickel ions therein are trapped on the nickel ion imprinting extraction membrane 30 in the extraction head 20 located on the outlet 111 when the water sample flows out. Moreover, the volume of the tube 11 is constant, and elution of equal volume or multiple volume can be achieved, which is convenient for the conversion of nickel ion concentration in the water sample. In addition, the nickel ion imprinting extraction device has a simple structure, is convenient for sampling and enriching nickel ions, and is convenient for absorbing eluent and eluting nickel ions. It is simple and easy to operate, and realizes on-site enrichment and extraction of nickel ions in water samples, and thus does not need to perform water sample collection protection (adding protective agent), storage and transportation, effectively avoiding the influence of various factors on the nickel ion concentration in water, and thus realizing rapid detection of nickel ions in water samples. Moreover, the nickel ion imprinting extraction device can be mass-produced and reused, which is suitable for promotion and application.

[0042] The disclosed embodiments can be applied to fields involving water quality detection and monitoring, such as the field of water environment detection and the field of water environment restoration and management. Specifically, the field of water environment detection includes: surface water, groundwater quality monitoring and water environment evaluation research work often requires accurate determination of the nickel content in the water to evaluate the water environment and water quality pollution status, and can provide fast and accurate on-site detection and monitoring data for this field. The field of water environment restoration and management includes: during the restoration and management of heavy metal nickel pollution in soil, surface water, and groundwater, high-frequency and long-period monitoring of the nickel content in the water is required to evaluate the degree of nickel pollution in the water quality and the restoration and management effect, and it can detect the nickel ion concentration in the water environment in real time on site, and provide real-time monitoring data for the water environment monitoring and restoration and management process in the field.

[0043] In the present disclosure, Figure 1 As shown, the sampling assembly 10 also includes an injection switch 13 and an outlet switch 14. The injection switch 13 is arranged on the injection port 112 of the tube 11, so that when the push-pull rod 12 is pushed, the injection port 112 is closed, ensuring that the fluid only flows out from the outlet 111. The outlet switch 14 is arranged on the outlet 111 of the tube 11 or the liquid outlet 22 of the extraction head 20, so that when the push-pull rod 12 is pulled, the outlet 111 is closed, ensuring that the fluid only flows into the tube 11 from the injection port 112.

[0044] In the sampling assembly 10, a scale line 110 is provided on the outer wall of the barrel 11, which is convenient for determining the sampling volume and the eluent volume. The maximum volume of the barrel 11 is not limited and can be determined according to actual conditions. Optionally, the maximum volume of the barrel 11 ranges from 100 mL to 200 mL, and a sampling assembly 10 with a barrel 11 of a suitable volume can be selected according to actual needs.

[0045] In the sampling assembly 10, the configuration of the sample outlet 111 and the sample inlet 112 at the second end of the tube 11 is not limited, as long as the sample inlet and sample outlet functions can be achieved. Figure 2 As shown, the second port of the tube 11 is used as the sample outlet 111, a through hole is provided on the side wall near the second port, and a liquid inlet pipe 130 is connected to the through hole, and the end of the liquid inlet pipe 130 is used as the sample inlet 112. The liquid inlet pipe 130 has a certain length to facilitate sampling. In this embodiment, the sample injection switch 13 is provided on the liquid inlet pipe 130.

[0046] It is understandable that in the sampling assembly 10 , the length of the push-pull rod 12 is greater than the length of the tube 11 , so as to ensure that part of the push-pull rod 12 exceeds the second end of the tube 11 , so as to facilitate pushing and pulling the push-pull rod 12 .

[0047] In the disclosed embodiment, the extraction head 20 is connected to the sample outlet of the tube 11 in any manner. The liquid inlet 21 of the extraction head 20 can be fixedly connected to the sample outlet 111 of the tube 11, or can be detachably connected to the sample outlet 111 of the tube 11.

[0048] Optionally, the liquid inlet 21 of the extraction head 20 is detachably connected to the sample outlet 111 of the tube 11. In this embodiment, the extraction head 20 is a detachable component to facilitate the replacement of the internal nickel ion imprinted extraction membrane 30. Of course, the sampling assembly 10 can also be equipped with multiple extraction heads 20. Only by replacing the extraction heads 20, the nickel ions in different water samples can be easily and quickly absorbed and eluted, which is convenient for multiple sampling on site and improves work efficiency.

[0049] In some embodiments, the extraction head 20 is connected to the sample outlet 111 of the tube 11 by threads. In practical applications, the inner wall of the liquid inlet 21 of the extraction head 20 is provided with an internal thread, and the outer wall of the sample outlet 111 of the tube 11 is provided with an external thread 113 (refer to Figure 2 shown).

[0050] In the disclosed embodiment, the nickel ion imprinted extraction membrane 30 can be covered in the flow channel 23 of the extraction head 20 to ensure that the water sample passing through the flow channel 23 passes through the nickel ion imprinted extraction membrane 30. It can be understood that the nickel ion imprinted extraction membrane 30 is a consumable, and therefore, the nickel ion imprinted extraction membrane 30 needs to be able to be taken out or put in from the extraction head 20. When the extraction head 20 is detachably connected to the tube 11, the nickel ion imprinted extraction membrane 30 can be taken out or put in from the liquid inlet 21 of the extraction head 20. When the extraction head 20 is fixedly connected to the tube 11, a loading port can be opened on the side wall of the extraction head, and the nickel ion imprinted extraction membrane 30 can be inserted or pulled out from the loading port; and after insertion, the loading port can be closed. For example, a sealing ring is sleeved on the outer peripheral wall where the loading port is located to close the loading port to prevent the loss of the water sample to be tested during the sampling process.

[0051] In some embodiments, reference Figure 5 As shown, the extraction head 20 further includes a support structure 24, which is disposed in the flow channel 23; the nickel ion imprinted extraction membrane 30 is disposed on the support surface of the support structure 24 on the side of the liquid inlet 21. The support structure 24 provides support for the nickel ion imprinted extraction membrane 30 to ensure that it will not be deformed by the impact of the fluid during the sample discharge and elution process, and the structure is not limited.

[0052] Optionally, the support structure 24 includes a plurality of support rods 241, which are radially connected and arranged. The shape of the outer ends of the plurality of support rods 241 is adapted to the cross-sectional shape of the flow channel 23 of the extraction head 20. The support structure 24 is arranged in the flow channel 23 in a manner perpendicular to the axial direction of the flow channel 23, thereby ensuring that the nickel ion imprinted extraction membrane 30 is perpendicular to the axial direction of the flow channel 23.

[0053] Optionally, the support structure 24 further includes an inner ring frame 242 and / or an outer ring frame 243. The inner ring frame 242 is connected to the inner ends of the plurality of support rods 241 connected in a radial shape. The outer ring frame 243 is connected to the outer ends of the plurality of support rods 241 connected in a radial shape, and the shape of the outer ring frame 243 is adapted to the cross-sectional shape of the flow channel 23 of the extraction head 20. The support structure 24 is more stable.

[0054] The arrangement of the support structure 24 in the flow channel 23 of the extraction head 20 is not limited. The support structure 24 can be fixed in the flow channel 23 by interference fit, or a connecting structure can be provided on the inner wall of the flow channel 23 to fix or lock the support structure 24, etc.

[0055] In some embodiments, Figure 3 As shown, the flow passage 23 of the extraction head 20 includes a straight section 231 and a constricted section 232 that are connected; the port of the straight section 231 serves as the liquid inlet 21, and the port of the constricted section 232 serves as the liquid outlet 22; the support structure 24 is disposed at the connection between the straight section 231 and the constricted section 232. In this embodiment, the change in the flow path cross section of the straight section 231 and the constricted section 232 plays a supporting and locking role for the support structure 24.

[0056] Optionally, the extraction head 20 further includes a rubber ring (not shown) disposed on the support surface of the support structure 24 on the side of the liquid inlet 21 to clamp the edge of the nickel ion imprinted extraction membrane 30 , thereby limiting the nickel ion imprinted extraction membrane 30 to a certain extent.

[0057] In some embodiments, the nickel ion imprinting extraction device further includes a heating component for heating the extraction head 20 to achieve heating of the fluid flowing through the extraction head 20 and / or heating of the nickel ion imprinting extraction membrane 30 placed in the extraction head 20. In this embodiment, a heating function is added to the extraction head 20 to obtain an extraction head with a heating function. The extraction head with a heating function in this embodiment is suitable for on-site rapid detection work in cold areas or low-temperature environments in the wild (where the temperature of the water sample to be detected is low and there is a tendency to freeze).

[0058] When testing water samples in cold regions or outdoor environments with low ambient temperature (e.g., below 5°C), the heating component is started to ensure that the temperature of the nickel ion imprinted extraction membrane 30 and / or the water sample directly contacting the nickel ion imprinted extraction membrane 30 is raised to a first set temperature (e.g., raised to not less than 5°C) during testing, thereby ensuring the enrichment and adsorption efficiency of the nickel ion imprinted extraction membrane 30. Accordingly, the on-site detection device can be applied to on-site rapid detection work in cold regions or low-temperature environments.

[0059] Optionally, the heating assembly includes a heating portion 41, and the heating portion 41 is disposed on the extraction head 20. The structure and arrangement of the heating portion 41 are not limited, and the extraction head 20 can be heated.

[0060] In one example, the heating portion 41 includes a heating sleeve, and the heating sleeve has a heating cavity that is adapted to the shape of the extraction head 20. When the extraction head 20 needs to be heated, the heating sleeve is placed outside the extraction head 20 and the heating sleeve is started to heat. In a specific application, the heating sleeve includes a sleeve body and a heating wire embedded in the sleeve body, and the heating wire is arranged around the heating cavity.

[0061] In another example, the heating portion 41 includes a heating core, and the heating core is embedded in the side wall of the extraction head 20 and / or the heating core is embedded in the support structure 24 of the extraction head 20 (see Figure 6 That is, the heating part 41 is embedded in the side wall of the extraction head 20 and / or the supporting structure 24, and forms an integral structure with the extraction head 20. Optionally, the heating core includes a heating wire. The heating cores arranged at different positions can be a series structure, a parallel structure, or a structure in which both series and parallel are arranged at the same time, without limitation.

[0062] In a specific application, for example Figure 5 In the support structure 24 shown, the heating core is embedded in each support rod 241 , and when the support structure 24 includes an inner ring frame 242 and / or an outer ring frame 243 , the heating core is also embedded in the inner ring frame 242 and / or the outer ring frame 243 .

[0063] In some embodiments, the heating assembly further includes a heating power supply 42, which is electrically connected to the heating portion 41 to provide voltage to the heating portion 41 to generate heat. In this embodiment, the heating power supply 42 can be a rechargeable power supply, which is suitable for application scenarios of field detection.

[0064] The heating power supply 42 can be fixedly connected to the heating part 41, that is, when the heating part 41 includes a heating sleeve, the heating power supply 42 can be fixedly arranged on the heating sleeve; when the heating part 41 includes a heating core, the heating power supply 42 can be fixedly arranged on the extraction head 20; it is convenient to take. The heating power supply 42 can also be separately arranged from the heating part 41, and when the heating part 41 needs to be heated, the heating part 41 is electrically connected to the heating power supply 42; it is convenient to charge or store the heating power supply 42.

[0065] In one example, the heating power source 42 is a micro-chargeable power source, which is convenient to carry, and when fixedly connected to the heating part 41, it is convenient to be fixedly set on the extraction head 20 or the heating sleeve.

[0066] In another example, the heating power source 42 includes a battery box and a battery / battery pack, the battery box has a placement cavity, a positive voltage output terminal and a negative voltage output terminal, and the two ends of the heating wire are electrically connected to the positive voltage output terminal and the negative voltage output terminal respectively; the battery / battery pack is placed in the placement cavity and the positive pole of the battery / battery pack is electrically connected to the positive voltage output terminal, and the negative pole is electrically connected to the negative voltage output terminal. In this application, the battery / battery pack can be a rechargeable battery or a dry cell, which is determined according to actual conditions. This example only gives a specific structure of the heating power source 42, but in actual applications, it is not limited to this example and can be selected according to actual needs.

[0067] In some embodiments, the heating assembly further comprises a controller 43 for controlling the power supply to the heating unit 41 when the ambient temperature is lower than the set temperature. In this embodiment, the preset temperature is set according to the critical temperature at which water is easy to freeze, for example, the set temperature is 5°C.

[0068] In one example, the controller 43 includes a temperature controller, and the temperature control terminal of the temperature controller is connected to the electrical connection line between the heating part 41 and the heating power supply 42; when the ambient temperature is lower than the set temperature, the temperature control terminal is turned on, so that the heating power supply 42 supplies power to the heating part 41. That is, when the ambient temperature is higher than the set temperature, the temperature control terminal of the temperature controller is in a disconnected state, so that the electrical connection line between the heating part 41 and the heating power supply 42 is in an open circuit state.

[0069] In this embodiment, the heating power of the heating component can be a fixed value, that is, regardless of the specific temperature value of the ambient temperature, as long as the ambient temperature is lower than the set temperature, the heating is performed with the fixed heating power, which is simple and effective. Of course, the heating power of the heating component can be changed accordingly according to the specific temperature value of the ambient temperature.

[0070] Optionally, the controller 43 is also used to determine the current heating power corresponding to the current ambient temperature according to the first correspondence between the ambient temperature and the heating power, and control the heating unit 41 to heat with the current heating power. Determining the heating power according to the ambient temperature can better control the temperature of the water sample after heating, so that the temperature of the water sample is controlled within a reasonable range. The reasonable range can be determined based on the requirements of ensuring the adsorption efficiency and low energy consumption of the nickel ion imprinted extraction membrane 30. The first correspondence between the ambient temperature and the heating power is pre-stored in the controller 43, and the first correspondence is determined based on the discharge rate of the nickel ion imprinted extraction device (see subsequent related content), the ambient temperature (which has a corresponding relationship with the water sample temperature) and the temperature of the water sample after heating.

[0071] In the nickel ion imprinting extraction device of the disclosed embodiment, the extraction head 20 can be equipped with two types, one is the extraction head 20 without a heating component, and the other is the extraction head 20 with a heating component and a heating function. In actual applications, it can be determined according to the ambient temperature.

[0072] In some embodiments, the nickel ion imprinted extraction device further includes a nickel ion imprinted extraction membrane 30, which is adapted to the flow channel 23 of the extraction head 20; and can be adapted to be disposed in the extraction head 20 and cover the flow channel 23 of the extraction head 20. In this embodiment, the nickel ion imprinted extraction device is equipped with an adapted nickel ion imprinted extraction membrane 30. In practical applications, the nickel ion imprinted extraction membrane 30 can be replaced according to specific usage conditions.

[0073] Of course, the nickel ion imprinted extraction membrane 30 is a membrane that enriches nickel ions. Users can prepare their own nickel ion imprinted extraction membrane 30 according to actual conditions. When using the nickel ion imprinted extraction device, the self-prepared nickel ion imprinted extraction membrane 30 can be covered and set in the flow channel 23 of the extraction head 20.

[0074] Optionally, the nickel ion imprinted extraction membrane 30 is covered and disposed in the flow channel 23 of the extraction head 20 in a manner that the nickel ion imprinted extraction membrane 30 is perpendicular to the axial direction of the flow channel 23 .

[0075] In the disclosed embodiment, the nickel ion imprinting extraction membrane 30 is not limited, as long as it is a membrane that can enrich nickel ions and extract and elute nickel ions.

[0076] In some embodiments, a nickel ion imprinted extraction membrane 30 includes a microporous base membrane and an imprinted polymer loaded on the microporous base membrane: wherein the imprinted polymer is obtained by immersing a prepolymerization solution into the microporous base membrane and then polymerizing it at a polymerization temperature.

[0077] The nickel ion imprinted extraction membrane 30 of the disclosed embodiment is based on a microporous base membrane, and the prepolymerized liquid is immersed in the microporous base membrane and in situ polymerized on the microporous base membrane at a polymerization temperature to form an imprinted polymer. The imprinted polymer itself has many microporous structures, and these microporous structures have specific structures and molecular forces, so that it has specific adsorption only for nickel ions, and weak adsorption for other substances / elements, so that it can effectively and specifically adsorb nickel ions and enrich nickel ions in water samples on the nickel ion imprinted extraction membrane 30, with strong adsorption capacity and high enrichment and adsorption efficiency. In addition, the imprinted polymer is in situ polymerized to form on the micropores of the microporous base membrane and the base membrane support skeleton, with uniform load, and the imprinted polymer has good binding force with the microporous base membrane and is not easy to fall off.

[0078] When a water sample containing nickel ions flows through the nickel ion imprinted extraction membrane 30, the nickel ions can be specifically adsorbed by the imprinted polymer and thus enriched on the nickel ion imprinted extraction membrane 30, and the nickel ions can be eluted by the eluent, thereby achieving the enrichment and elution of nickel ions, especially the enrichment of trace nickel ions, and achieving the detection of trace nickel ions in water. In addition, after the nickel ions are eluted, the imprinted polymer restores the adsorption function, so that the next enrichment operation can be performed, so the nickel ion imprinted extraction membrane 30 can be reused. Of course, the user can replace the new nickel ion imprinted extraction membrane 30 according to the number of reuses.

[0079] In the disclosed embodiment, the thickness of the nickel ion imprinted extraction membrane 30 is determined according to the actual application. For example, the thickness of the nickel ion imprinted extraction membrane 30 is 0.1 mm to 0.5 mm. Optionally, the thickness of the nickel ion imprinted extraction membrane 30 is 0.2 mm to 0.3 mm. The porosity of the microporous base membrane used is 70% to 85%.

[0080] In the disclosed embodiment, the imprinted polymer can be any polymer capable of absorbing nickel ions, without specific limitation. The polymerization temperature and polymerization time required for the prepolymer solution to polymerize the corresponding imprinted polymer can be determined according to the specific type of imprinted polymer.

[0081] In some embodiments, the prepolymer solution includes nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide, and the usage ratios of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are 1 mmol﹕1 mmol﹕3~6 mmol﹕15~25 mmol﹕40~60 mg﹕10~20 mL respectively. The imprinted polymer formed by the polymerization of the prepolymer solution of this embodiment has many microporous structures, and has a specific structure and molecular force, so that it has specific adsorption only for nickel ions, and has weak adsorption capacity for other substances / elements (for example, common iron, aluminum, copper, zinc, lead, cadmium and other metal ions in water), so that it can effectively adsorb nickel ions and exclude the interference of other metal ions, and effectively extract and adsorb nickel ions in water samples while purifying water samples, thereby further improving the accuracy of nickel ion detection in water. Further in conjunction with the structure of the microporous base membrane, efficient enrichment of nickel ions is achieved, and the enrichment and adsorption efficiency of nickel ions can reach 90% or more, to ensure the accuracy of nickel ion detection in water samples.

[0082] Optionally, the components of the prepolymer solution are mixed according to their respective amounts and then mixed evenly. The mixing method is not limited to one or a combination of oscillation, ultrasound and stirring.

[0083] Optionally, after mixing and evenly mixing some of the components of the prepolymer solution according to their respective amounts, the remaining components are added and evenly mixed. Specifically, first, nickel acetate, diphenylthioazocarbonyl hydrazide and 2-(diethylamino)ethyl methacrylate are added to dimethyl sulfoxide for mixed dissolution, and oscillated for mixing; then styrene and 2,2'-diazoisobutyronitrile are added in sequence, and ultrasonic mixing is performed to form a prepolymer solution. In this embodiment, the oscillation time is not limited and is determined according to the actual dissolution situation, for example, oscillation is performed for 6h to 10h. The ultrasonic time is also not limited and is determined according to the actual situation, for example, ultrasonic 20min to 50min.

[0084] In this embodiment, the prepolymer solution is polymerized at a polymerization temperature of 55° C. to 65° C. to form the imprinted polymer. That is, in the nickel ion imprinted extraction membrane 30, the imprinted polymer is obtained by immersing the prepolymer solution in the microporous base membrane and polymerizing it at a polymerization temperature of 55° C. to 65° C. Optionally, the polymerization temperature is 60° C.

[0085] Optionally, the imprinted polymer is obtained by immersing the prepolymer solution into the microporous base membrane and polymerizing it at a polymerization temperature of 55° C. to 65° C. for 20 to 30 hours. The specific value of the polymerization time is determined according to actual conditions.

[0086] Optionally, the usage ratios of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are 1 mmol﹕1 mmol﹕4-5 mmol﹕18-22 mmol﹕45-55 mg﹕10-15 mL respectively.

[0087] Optionally, the usage ratios of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are 1 mmol﹕1 mmol﹕5 mmol﹕20 mmol﹕50 mg﹕12 mL respectively.

[0088] In the disclosed embodiment, the microporous base membrane is a matrix having many micropores in its body, which can effectively load the imprinted polymer. In some embodiments, the microporous base membrane is obtained by applying the casting liquid to the mold and solidifying it; wherein the casting liquid includes vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10: (1-3): (5-10): (1-3): (0.1-0.5): (25-30): (50-60). In the microporous base membrane obtained in this embodiment, the micropores are numerous and uniform, and can effectively load the imprinted polymer.

[0089] In this embodiment, after the components of the casting liquid are mixed in proportion, a step-by-step heating method is used to dissolve and mix, and then the corresponding casting liquid is obtained by constant temperature degassing. Among them, the temperature range in the step-by-step heating method is controlled at 50°C to 80°C, and the dissolution is divided into two, three or more stages of segmented heating; the heating time of each stage of heating is determined according to the actual situation. Optionally, the step-by-step heating method includes heating at 50°C to 60°C for 30min to 40min, then heating to 70°C to 80°C and dissolving at this temperature for 8h to 8.5h. Optionally, the step-by-step heating method includes heating at 50°C for 40min, then heating to 80°C and dissolving at this temperature for 8h.

[0090] In the constant temperature degassing, the degassing temperature is controlled within the range of 60°C to 70°C, and the degassing time is controlled within the range of 7.5h to 8.5h. Optionally, the constant temperature degassing is performed at 60°C for 8h.

[0091] In this embodiment, the mold is determined according to the shape required for the microporous base membrane. For example, a mold with a circular cross section is used to obtain a circular microporous base membrane. The material of the mold is selected to be a material that is easy to demold, such as glass.

[0092] In some embodiments, the solidification method includes sequential room temperature solidification and water bath solidification. Optionally, the casting liquid is applied to the mold, and after room temperature solidification and water bath solidification, it is washed and dried to obtain a microporous base membrane. Among them, the room temperature solidification method is to place the mold coated with the casting liquid at room temperature for 15s to 30s for pre-solidification. Then the mold after the pre-solidification treatment is immersed in deionized water for film formation in a water bath. The time required for film formation in the water bath is not limited and can be determined according to the actual film formation situation. After film formation, the membrane is taken out, and the membrane is washed and dried to obtain a microporous base membrane. In this embodiment, the drying temperature is controlled at 35°C to 45°C, and optionally, the drying temperature is controlled at 40°C.

[0093] Optionally, the casting solution includes vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10:2:7:2:0.2:27:52.

[0094] The present disclosure also provides a method for preparing a nickel ion imprinted extraction membrane, which comprises the following steps:

[0095] S10. Preparation of microporous base membrane:

[0096] S11. Mix vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10:(1-3):(0.1-0.5):(25-30):(50-60), heat to dissolve, and then degas to obtain a casting solution.

[0097] S12, coating the casting liquid in the mold, putting it into a water bath to solidify into a membrane after pre-forming, and then washing and drying to obtain a microporous base membrane.

[0098] S20, Preparation of Nickel Ion Imprinted Extraction Membrane:

[0099] S21. Mix nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide in the proportion of 1 mmol﹕1mmol﹕3-6mmol﹕15-25mmol﹕40-60mg﹕10-20mL to form a prepolymer solution.

[0100] S22, immersing the microporous base membrane obtained in step S10 in the prepolymerization solution for a first period of time, taking it out and polymerizing it at the polymerization temperature for a second period of time, washing it and drying it, to obtain a nickel ion imprinted extraction membrane.

[0101] In the nickel ion imprinted extraction membrane 30 prepared by the preparation method of the disclosed embodiment, the micropores in the microporous base membrane are evenly distributed and have a high porosity (70% to 85%). On the microporous base membrane (the nickel ion imprinted polymer is not only in the micropores of the microporous base membrane, but also polymerized on the base membrane support skeleton), it can be in situ polymerized to form an imprinted polymer. The imprinted polymer can specifically adsorb nickel ions in the water sample flowing through, has strong adsorption capacity, and high enrichment and adsorption efficiency, further ensuring the accuracy of nickel ion detection in water. Moreover, the imprinted polymer formed on the microporous base membrane by in situ polymerization is evenly loaded, has good bonding with the microporous base membrane, and is not easy to fall off. At the same time, it also has good stability and reusability.

[0102] In step S11, the heating and dissolving method is not limited, and the material may be directly heated to a first heating temperature and heated at the first heating temperature for a first heating time to complete the heating and dissolving. A step-by-step heating method may also be used for heating and dissolving.

[0103] Optionally, a step-by-step heating method is used for heating and dissolving, in which the temperature range is controlled at 50°C to 80°C, and the heating and dissolving is divided into two, three or more stages; wherein the heating time for each stage of heating is determined according to the actual situation. Optionally, the step-by-step heating method includes heating at 50°C to 60°C for 30min to 40min, then heating to 70°C to 80°C and dissolving at this temperature for 8h to 8.5h. Optionally, the step-by-step heating method includes heating at 50°C for 40min, then heating to 80°C and dissolving at this temperature for 8h.

[0104] In step S11, the degassing is performed at a constant temperature, and in the constant temperature degassing, the degassing temperature is controlled in the range of 60° C. to 70° C., and the degassing time is controlled in the range of 7.5 hours to 8.5 hours. Optionally, the degassing includes constant temperature degassing at 60° C. for 8 hours.

[0105] Optionally, in step S11, vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate are mixed in a weight ratio of 10:2:7:2:0.2:27:52.

[0106] In step S12, the mold is determined according to the shape required for the microporous basement membrane. For example, a mold with a circular cross section is used to obtain a circular microporous basement membrane. The material of the mold is selected to be a material that is easy to demold, such as glass. For example, the glass mold supporting the extraction head 20 in the nickel ion imprinting extraction device described later.

[0107] In some embodiments, in step S12, preforming includes placing the mold coated with the casting liquid at room temperature for 15 seconds to 30 seconds. Optionally, placing the mold coated with the casting liquid at room temperature for 20 seconds.

[0108] In step S12, the mold after the preforming treatment is immersed in a water bath to form a film. The time required for film formation in the water bath is not limited and can be determined according to the actual film formation situation. After the film is formed, the membrane is taken out, and the membrane is washed and dried to obtain a microporous base membrane. Among them, the washing method is not limited, for example, after washing with deionized water for multiple times, it is immersed. The drying temperature can be controlled at 35°C to 45°C, and optionally, the drying temperature is controlled at 40°C.

[0109] In step S12, the coating thickness of the casting solution in the mold is determined according to the required microporous base membrane thickness. The coating thickness is substantially consistent with the microporous base membrane thickness.

[0110] In step S21 of the embodiment of the present disclosure, the preparation method of the prepolymer solution is not limited, and a reasonable mixing and blending method can be determined based on the physical and chemical properties of each component.

[0111] Optionally, in step S21, the components of the prepolymer solution are mixed according to their respective usage ratios and then mixed evenly. The mixing method is not limited to one or a combination of oscillation, ultrasound and stirring.

[0112] Optionally, in step S21, after some of the components of the prepolymer solution are mixed and mixed according to their respective usage ratios, the remaining components are added and mixed. Specifically, nickel acetate, diphenylthioazocarbonyl hydrazide and 2-(diethylamino)ethyl methacrylate are first added to dimethyl sulfoxide for mixed dissolution, and oscillated for mixing; then styrene and 2,2'-diazoisobutyronitrile are added in sequence, and ultrasonic mixing is performed to form a prepolymer solution. In this embodiment, the oscillation time is not limited and is determined according to the actual dissolution situation, for example, oscillation is 6h to 10h. The ultrasonic time is also not limited and is determined according to the actual situation, for example, ultrasonic 20min to 50min.

[0113] In step S21, optionally, nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are uniformly mixed in a ratio of 1 mmol﹕1 mmol﹕4-5 mmol﹕18-22 mmol﹕45-55 mg﹕10-15 mL.

[0114] Optionally, nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are uniformly mixed in a ratio of 1 mmol﹕1 mmol﹕5 mmol﹕20 mmol﹕50 mg﹕12 mL.

[0115] In step S22, the first time length is determined based on basic physical parameters of the microporous base membrane, such as thickness and porosity. Optionally, the first time length is 20s to 30s.

[0116] In step S22, the polymerization temperature and the second duration (i.e., polymerization duration) are determined based on the prepolymerization liquid obtained in step S21. Optionally, the polymerization temperature is 55°C to 65°C, and the second duration is 20h to 30h. Optionally, the polymerization temperature is 60°C, and the second duration is 20h to 30h. The specific value of the second duration is determined based on actual conditions.

[0117] In step S22, washing includes ultrasonic washing with a mixed solution of ethanol / acetic acid (volume ratio 8:1). The washing time is determined according to the actual situation, for example, ultrasonic washing for 4 hours to 6 hours. Optionally, ultrasonic washing for 5 hours.

[0118] The present disclosure also provides a method for detecting nickel ions in water, comprising:

[0119] Step S100, enriching nickel ions in the water sample to be tested: using the aforementioned nickel ion imprinting extraction device, a first preset volume of the water sample to be tested is sucked into the tube 11 through the sample inlet 112, and then the water sample to be tested is discharged through the sample outlet 111, thereby enriching the nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane 30.

[0120] Step S200, eluting the nickel ions on the nickel ion imprinted extraction membrane 30: a second preset volume of eluent is drawn into the tube 11 through the inlet 112 of the nickel ion imprinted extraction device, and then the eluent is discharged through the outlet 111. When the eluent flows through the nickel ion imprinted extraction membrane 30, the nickel ions on it are eluted, and the eluted nickel ions flow out of the tube 11 with the eluent to obtain an eluent.

[0121] Step S300, color development and phase change: add a color developer solution and a magnesium sulfate solution to the eluent, shake and mix, then add a third preset volume of n-butanol, shake and mix, let stand to separate layers, and obtain the upper organic phase as the sample to be tested.

[0122] Step S400, performing absorbance measurement or colorimetric visual inspection on the sample to be tested, and determining the nickel ion mass concentration in the water sample to be tested according to the absorbance-nickel ion mass concentration standard curve or the standard colorimetric card / tube.

[0123] The nickel ion detection method in the water of the disclosed embodiment is simple to operate. It only needs to pull or push the push-pull rod 12 to realize the removal and discharge of the water sample / eluent, thereby relatively completing the enrichment / extraction elution. At the same time, the detection method can be completed on-site, accurately and quickly, without the need for water sample collection protection (adding protective agents), storage and transportation, and effectively avoids the influence of various factors on the nickel ion concentration in water. Moreover, the timeliness of testing nickel ions in water is much higher than that of laboratory analysis methods. The on-site detection and analysis of the disclosed embodiment only requires 20 to 30 minutes per sample, and the timeliness is strong. In addition, the on-site detection method of the disclosed embodiment has low testing cost. It only needs to collect a certain volume of water samples on-site, without collecting a large number of samples and adding protective agents, and there is no storage and transportation cost, and there is no need to use large-scale laboratory analysis instruments. Overall, the testing cost is very low.

[0124] The detection limit of the method for detecting nickel ions in water of the embodiment of the present disclosure is low, and can achieve the detection of trace amounts of nickel ions, with the detection limit reaching 0.007 mg / L.

[0125] In the disclosed embodiment, in step S100, the first preset volume of the water sample to be tested can be enriched with nickel ions in one suction / sampling operation or in multiple suction / sampling operations according to the volume of the tube 11 of the nickel ion imprinting extraction device. For example, if the volume of the tube 11 is 200mL and the volume of the water sample to be tested is 200mL, then one suction / sampling operation is performed to complete the enrichment of nickel ions. For another example, if the volume of the tube 11 is 200mL and the volume of the water sample to be tested is 400mL, then two suction / sampling operations are performed to complete the enrichment of nickel ions.

[0126] It is understood that in step S100, in the process of discharging the water sample to be tested through the sample outlet 111, the effective enrichment of nickel ions on the nickel ion imprinted extraction membrane 30 is ensured by controlling the discharge rate. In some embodiments, the discharge rate of the water sample to be tested through the sample outlet 111 is 15 to 25 mL / min. Optionally, the discharge rate of the water sample to be tested through the sample outlet 111 is 20 mL / min.

[0127] In the disclosed embodiment, in step S200, the eluent extracts the nickel ions enriched on the nickel ion imprinting extraction membrane 30 and can achieve a certain degree of concentration of the nickel ions. The second preset volume of the eluent is a fixed value, which is consistent with the volume of the eluent in the process of drawing the absorbance-nickel ion mass concentration standard curve or making the standard colorimetric card / tube. Moreover, in general, the standard volume for drawing the absorbance-nickel ion mass concentration standard curve or making the standard colorimetric card / tube is the volume of the tube 11 of the nickel ion imprinting extraction device. Optionally, the second preset volume is one-fifth to one-tenth of the volume of the tube 11.

[0128] In a practical application, the volume of the tube 11 is 200 mL, and the second preset volume is 20 mL to 40 mL. Optionally, the second preset volume is 20 mL to 30 mL. Optionally, the second preset volume is 20 mL.

[0129] In another practical application, the volume of the tube 11 is 100 mL, then the second preset volume is 10 mL to 20 mL. Optionally, the second preset volume is 10 mL to 15 mL. Optionally, the second preset volume is 10 mL or 15 mL.

[0130] In some embodiments, in step S200, the eluent includes sodium acetate solution and acetic acid, the volume ratio of sodium acetate solution to acetic acid is 1:0.5-1.5, and the concentration of sodium acetate solution is 1 mol / L. Optionally, the eluent includes sodium acetate solution (concentration is 1 mol / L) and acetic acid, and the volume ratio of sodium acetate solution to acetic acid is 1:0.8-1.2. Optionally, the eluent includes sodium acetate solution (concentration is 1 mol / L) and acetic acid, and the volume ratio of sodium acetate solution to acetic acid is 1:1. In this embodiment, the solvent in the sodium acetate solution is water; acetic acid is liquid acetic acid purchased on the market, which is a solution itself.

[0131] In some embodiments, in step S200, the discharge rate of the eluent through the sample outlet 111 is 4-6 mL / min. Optionally, the discharge rate of the eluent through the sample outlet 111 is 5 mL / min.

[0132] In step S300, after color development is completed using a color developer solution and a magnesium sulfate solution, nickel ions are extracted into an organic phase of n-butanol to obtain a test sample containing nickel ions. The color developer solution is not limited, and any reagent that can color the eluent can be used.

[0133] In some embodiments, the developer solution is a developer N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide solution. Wherein, N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide is synthesized by the following method: step a, dissolving N-ethylcarbazole-3-formaldehyde in ethanol to obtain solution A, wherein the ratio of N-ethylcarbazole-3-formaldehyde to ethanol is 2g-4g﹕100mL; dissolving hydrazine carbosulfamide in ethanol solution to obtain solution B, wherein the ratio of hydrazine carbosulfamide to ethanol solution is 5g-8g﹕100mL; step b, mixing solution A and solution B evenly, reflux reaction in a water bath, and then standing at room temperature to precipitate; then filtering, washing, and drying to obtain a crude product; step c, recrystallizing the crude product to obtain N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide. N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide is used as a color developer, which has simple synthesis, stable physical and chemical properties, rapid color development, and is very suitable for the detection and analysis of nickel ions in water. The solvent in the color developer N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide solution is ethanol.

[0134] Optionally, in step a, the ethanol in solution A is pure ethanol with a concentration of more than 95%.

[0135] Optionally, in step a, the ratio of N-ethylcarbazole-3-carboxaldehyde to ethanol is 3 g:100 mL.

[0136] Optionally, in step a, the concentration of the ethanol solution in solution B is 40% to 60%. Optionally, in step a, the concentration of the ethanol solution in solution B is 50%.

[0137] Optionally, in step a, the ratio of hydrazinocarbonylthioamide to ethanol solution is 6 g:100 mL.

[0138] Optionally, in step b, solution A and solution B are mixed evenly, and refluxed in a water bath for 2.5 h to 3.5 h.

[0139] Optionally, the concentration of the color developer N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide solution is 1 g / L to 2 g / L. Optionally, the concentration of the color developer N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide solution is 1.5 g / L.

[0140] Of course, the color developer in step S300 is not limited to the aforementioned N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazide, and other commercially available or publicly available color developers may also be used without limitation.

[0141] In step S300 of the embodiment of the present disclosure, the magnesium sulfate solution is a salting-out reagent, which can positively promote the extraction of the nickel ion complex and improve the extraction efficiency. Optionally, the concentration of the magnesium sulfate solution is 10 g / L to 15 g / L. Optionally, the concentration of the magnesium sulfate solution is 12 g / L.

[0142] Optionally, the volume ratio of the developer solution to the magnesium sulfate solution is 1:1, and the volume ratio of the developer solution (or magnesium sulfate solution) to the eluent is 1:15 to 25. Optionally, the volume ratio of the developer solution (or magnesium sulfate solution) to the eluent is 1:20.

[0143] In step S300, n-butanol extracts nickel ions into it to form an organic extraction phase, and the third preset volume of n-butanol is not greater than the second preset volume of the eluent, so as to further concentrate the nickel ion concentration. Optionally, the ratio of the second preset volume to the third preset volume (defined as the extraction ratio) is 1 to 3:1. Optionally, the extraction ratio is 2:1. That is, the volume ratio of the eluent to n-butanol is 1 to 3:1. Optionally, the volume ratio of the eluent to n-butanol is 2:1.

[0144] In some embodiments, in step S400, the absorbance of the sample to be tested is measured, and the mass concentration of nickel ions in the water sample to be tested is determined according to a standard curve of absorbance-nickel ion mass concentration; including:

[0145] S411, using a spectrophotometer to measure the absorbance of the sample to be tested, to obtain the sample absorbance value of the sample to be tested;

[0146] S412, obtaining the nickel ion mass concentration of the sample corresponding to the absorbance value of the sample according to the absorbance-nickel ion mass concentration standard curve;

[0147] S413, according to ρ=C / f, determining the mass concentration of nickel ions in the water sample to be tested;

[0148] Wherein, ρ is the nickel ion mass concentration in the water sample to be tested, mg / L; C is the nickel ion mass concentration of the sample, mg / L; f is the ratio of the volume of the water sample to be tested (the first preset volume) to the standard volume, wherein the standard volume is the volume of the standard solution in the process of determining the absorbance-nickel ion mass concentration standard curve, which is a constant.

[0149] In some embodiments, a method for drawing a standard curve of absorbance-nickel ion mass concentration includes:

[0150] S412a. Prepare standard solutions of a series of concentrations.

[0151] Here, the standard solution of series concentration may include 0, 0.03 mg / L, 0.05 mg / L, 0.10 mg / L, 0.20 mg / L, 0.40 mg / L, 0.60 mg / L series standard solution. Of course, it is not limited to the standard solution of the concentration listed above.

[0152] S412b, using the aforementioned nickel ion imprinting extraction device, a standard volume of standard solution is sucked into the tube 11 through the injection port 112, and then the standard solution is discharged through the outlet port 111, so that the nickel ions in the standard solution are enriched on the nickel ion imprinting extraction membrane 30.

[0153] S412c, a second preset volume of eluent is drawn into the tube 11 through the injection port 112 of the nickel ion imprinting extraction device, and then the eluent is discharged through the outlet 111. When the eluent flows through the nickel ion imprinting extraction membrane 30, the nickel ions on it are eluted, and the eluted nickel ions flow out of the tube 11 along with the eluent to obtain the eluent.

[0154] The series of standard solutions are respectively subjected to the operations of step S412b and step S412c to obtain the corresponding series of standard eluents.

[0155] S412d, respectively add a color developer solution and a magnesium sulfate solution to the series of standard eluents, shake and mix, then respectively add a third preset volume of n-butanol, shake and mix, stand and separate, obtain the upper organic phase, and obtain a series of standard test samples.

[0156] S412e, pour the series of standard test samples into colorimetric tubes respectively, and place them in the colorimetric wells in turn for absorbance measurement to obtain the absorbance of the corresponding series of standard solutions. Among them, the absorbance measurement parameters include: selecting the single wavelength detection mode in the portable spectrophotometer, the detection wavelength is 390nm, and the instrument is zeroed with a blank sample of 0.0mg / L as the reference solution. Then, a standard curve is drawn with the absorbance of the series of standard solutions as the horizontal coordinate and the nickel ion concentration of the series of standard solutions as the vertical coordinate to obtain the absorbance-nickel ion mass concentration standard curve.

[0157] In the method for drawing the absorbance-nickel ion mass concentration standard curve of the embodiment of the present disclosure, the eluent, color developer solution, magnesium sulfate solution, n-butanol, and their respective volumes and concentrations, as well as other operating parameters are all consistent with those in the aforementioned method for detecting nickel ions in water to ensure the consistency of the detection conditions.

[0158] Optionally, in step S412e, after drawing the standard curve, the step further includes: calculating a standard linear equation. Substituting the absorbance of the tested sample (the tested sample obtained in the aforementioned step S300) into the standard linear equation, the mass concentration of the sample nickel ions in the corresponding tested sample can be conveniently obtained.

[0159] In a specific application, the method for drawing the absorbance-nickel ion mass concentration standard curve adopts the aforementioned steps S412a to S412e, wherein the standard volume of the standard solution is 200mL, the eluent includes a sodium acetate solution (concentration of 1 mol / L) and acetic acid with a volume ratio of 1:1, and the amount of the eluent is 20mL; 1mL of a color developer N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide solution with a concentration of 1.5g / L, 1mL of a magnesium sulfate solution with a concentration of 12g / L, and 10mL of n-butanol. The obtained absorbance-nickel ion mass concentration standard linear equation is C=0.4453A+0.0027. Where A is the absorbance and C is the mass concentration, mg / L.

[0160] In other embodiments, in step S400, the sample to be tested is subjected to colorimetric visual inspection, and the mass concentration of nickel ions in the water sample to be tested is determined according to the standard colorimetric card / tube; including: S421, making a standard colorimetric card or a standard colorimetric tube. S422, visually comparing the sample to be tested with the standard colorimetric card or the standard colorimetric tube to determine the mass concentration of nickel ions in the water sample to be tested. The colorimetric visual inspection method of this embodiment is suitable for the detection of water samples with high nickel ion concentration. Although the accuracy is slightly lower, the detection time is shorter and the timeliness is stronger. The determination method of step S400 can be determined according to the actual situation of the water sample to be tested.

[0161] Wherein, the preparation of the standard colorimetric card or standard colorimetric tube in step S421 includes: S421a, configuring a series of standard solutions of concentration. Here, the series of standard solutions of concentration may include a series of standard solutions of 0, 0.03mg / L, 0.05mg / L, 0.10mg / L, 0.20mg / L, 0.40mg / L, and 0.60mg / L. Of course, it is not limited to the standard solutions of the concentrations listed above. S421b, subjecting the series of standard solutions of concentration to a color reaction, and then preparing a standard colorimetric card or a standard colorimetric tube according to the concentration and color depth of the standard solution.

[0162] The disclosed embodiment also provides a nickel ion detection kit in water, including the aforementioned nickel ion imprinting extraction device and a reagent combination. The nickel ion imprinting extraction device can absorb the water sample to be tested through the sample inlet 112 and then discharge the water sample to be tested through the sample outlet 111, thereby enriching the nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane 30. The reagent combination includes an eluent, a color developer solution, a magnesium sulfate solution and n-butanol, and the eluent is used to elute the nickel ions enriched on the nickel ion imprinting extraction membrane 30 of the nickel ion imprinting extraction device to obtain an eluent; by sequentially adding the color developer solution, the magnesium sulfate solution and the n-butanol solution to the eluent, a sample to be tested containing nickel ions is obtained.

[0163] In the nickel ion detection box in the water of the disclosed embodiment, in addition to the nickel ion imprinting extraction device, it is also equipped with a reagent combination supporting the detection process, which is convenient to use, and then it is convenient to obtain the test sample containing nickel ions. Afterwards, the absorbance of the test sample is measured by a spectrophotometer, and the nickel ion concentration in the test sample is determined based on the correlation between the absorbance and the nickel ion concentration. Alternatively, the mass concentration of nickel ions in the water sample to be tested is determined by visual comparison with a colorimetric card or a colorimetric tube using a colorimetric visual method. Thereby, on-site rapid detection of the nickel ion content in the water sample is achieved.

[0164] In some embodiments, the nickel ion detection box in water also includes a data processing device, which is configured to obtain the sample nickel ion mass concentration corresponding to the sample absorbance value of the sample to be tested according to the absorbance-nickel ion mass concentration standard curve; and determine the mass concentration of nickel ions in the water sample to be tested according to the multiple relationship between the volume of the sample to be tested and the volume of the water sample to be tested and the sample nickel ion mass concentration. The drawing of the absorbance-nickel ion mass concentration standard curve refers to the above-mentioned relevant content and will not be repeated here.

[0165] Optionally, the mass concentration of nickel ions in the water sample to be tested is determined based on the multiple relationship between the volume of the sample to be tested and the volume of the water sample to be tested and the mass concentration of nickel ions in the sample; including: determining the mass concentration of nickel ions in the water sample to be tested according to ρ=C / f; wherein ρ is the mass concentration of nickel ions in the water sample to be tested, mg / L; C is the mass concentration of nickel ions in the sample, mg / L; f is the dilution multiple of the volume of the water sample to be tested relative to the standard volume, wherein the standard volume is the volume of the standard solution in the process of drawing the absorbance-nickel ion mass concentration standard curve, which is a constant.

[0166] Optionally, the linear equation of the absorbance-nickel ion mass concentration standard curve is: C=0.4453A+0.0027; wherein A is the absorbance and C is the mass concentration, mg / L.

[0167] It is understandable that the data processing device can be a microprocessor with simple computing functions, which can input the sample absorbance value of the sample to be tested and output the mass concentration value of nickel ions in the water sample to be tested.

[0168] Optionally, it can be installed on a smart terminal device in the form of an application (Application, APP).

[0169] In other embodiments, the nickel ion detection kit in water further comprises a standard colorimetric card or a standard colorimetric tube. In this embodiment, the standard colorimetric card or the standard colorimetric tube is obtained by color development with a series of nickel ion standard solutions of different concentrations. Referring to the contents of the aforementioned steps S421 to S422, no further description is given here.

[0170] In the disclosed embodiment, the reagent combination can be configured in multiple groups, and only one group of reagent combinations needs to be opened for each test, which is convenient and fast.

[0171] In the embodiments of the present disclosure, the composition of the eluent and the proportion of each component refer to the aforementioned relevant content, the color developer solution refers to the aforementioned relevant content, the magnesium sulfate solution refers to the aforementioned relevant content, the usage ratio of the eluent, color developer solution, magnesium sulfate solution and n-butanol refers to the aforementioned relevant content, and other related parameters involved refer to the aforementioned relevant content, which will not be repeated here.

[0172] In a practical application, the volume of the tube 11 of the nickel ion imprinting extraction device is 200 mL; the reagent combination includes: 20 mL of eluent (1 mol / L sodium acetate solution and acetic acid with a volume ratio of 1:1), 1 mL of a color developer N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide solution with a concentration of 1.5 g / L, 1 mL of a magnesium sulfate solution with a concentration of 12 g / L, and 10 mL of n-butanol.

[0173] In some embodiments, the developer solution is a developer N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide solution. Wherein, N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide is synthesized by the following method: step a, dissolving N-ethylcarbazole-3-formaldehyde in ethanol to obtain solution A, wherein the ratio of N-ethylcarbazole-3-formaldehyde to ethanol is 2g~4g﹕100mL; dissolving hydrazine carbosulfamide in ethanol solution to obtain solution B, wherein the ratio of hydrazine carbosulfamide to ethanol solution is 5g~8g﹕100mL; step b, mixing solution A and solution B evenly, reflux reaction in a water bath, and then standing at room temperature to precipitate; then filtering, washing, and drying to obtain a crude product; step c, recrystallizing the crude product to obtain N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide. N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide is used as a developer. For the specific content of this embodiment, please refer to the relevant content of the aforementioned method for detecting nickel ions in water, which will not be repeated here.

[0174] Specific examples are given below to illustrate the embodiments of the present disclosure.

[0175] Example 1 Nickel Ion Imprinting Extraction Device

[0176] like Figures 1 to 5 As shown, the nickel ion imprinting extraction device includes a sampling assembly 10 and an extraction head 20, the sampling assembly 10 includes a tube 11 and a push-pull rod 12, the push-pull rod 12 is slidably inserted into the tube 11 from the first end of the tube 11, the second port of the tube 11 is used as a sample outlet 111, a through hole is opened on the side wall near the second port, and a liquid inlet pipe 130 is connected to the through hole, and the end of the liquid inlet pipe 130 is used as a sample inlet 112. A scale mark 110 is set on the outer wall of the tube body of the tube 11. A sample inlet switch 13 is set on the liquid inlet pipe 130.

[0177] The extraction head 20 is provided with a liquid inlet 21 and a liquid outlet 22, and a flow channel 23 is formed between the liquid inlet 21 and the liquid outlet 22, and the liquid inlet 21 is detachably connected to the sample outlet 111 of the tube 11. The flow channel 23 includes a connected straight section 231 and a constricted section 232; the port of the straight section 231 serves as the liquid inlet 21, and the port of the constricted section 232 serves as the liquid outlet 22; the support structure 24 is provided at the connection between the straight section 231 and the constricted section 232. The support structure 24 includes a plurality of support rods 241, and the plurality of support rods 241 are radially connected. The flow channel 23 of the extraction head 20 can be covered with a nickel ion imprinting extraction membrane 30.

[0178] Example 2 Nickel Ion Imprinting Extraction Device

[0179] like Figures 1 to 7As shown, on the basis of the nickel ion imprinting extraction device of Example 1, a heating component is additionally provided on the extraction head 20. Specifically, the heating component includes a heating core (heating part 41), a micro-charging power supply (heating power supply 42) and a controller 43. The heating core is buried in the side wall of the extraction head 20 (not shown) and in the support structure 24 of the extraction head 20. The micro-charging power supply is fixedly arranged on the extraction head 20, and the controller 43 is arranged on the extraction head 20. The support structure 24 includes a plurality of support rods 241, an inner ring frame 242 and an outer ring frame 243. The heating core includes a plurality of first heating cores buried in each support rod 241 of the extraction head 20, an inner ring heating core buried in the inner ring frame 242 and a non-closed outer ring heating core buried in the outer ring frame 243, and the two ends of each first heating core are respectively conductively connected to the inner ring heating core and the outer ring heating core. The voltage output end of the micro-charging power supply is conductively connected to the two ends of the non-closed end of the outer ring heating core. The controller 43 specifically adopts a temperature controller 43, and the temperature control end of the temperature controller 43 is connected to the electrical connection circuit between the heating core (outer ring heating core) and the heating power supply 42; when the ambient temperature is lower than the set temperature, the control end is turned on, so that the charging power supply supplies power to the heating core with the set heating power.

[0180] Example 3 Nickel Ion Imprinted Extraction Membrane

[0181] The nickel ion imprinted extraction membrane comprises a microporous base membrane and an imprinted polymer loaded on the microporous base membrane: the imprinted polymer is obtained by immersing a prepolymerization liquid into the microporous base membrane and then polymerizing at a polymerization temperature of 55-65°C. The microporous base membrane is obtained by applying a casting liquid to a mold and solidifying it; wherein the casting liquid includes vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10:2:7:2:0.2:27:52; the prepolymer liquid includes nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide, and the usage ratio of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide is 1mmol:1mmol:5mmol:20mmol:50mg:12mL.

[0182] The preparation method of the nickel ion imprinted extraction membrane of this embodiment 3 is as follows:

[0183] Preparation of microporous base membrane: Vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate are mixed in a weight ratio of 10:2:7:2:0.2:27:52, and then heated to 50°C ~ 60°C for 30min ~ 40min, and then heated to 70°C ~ 80°C and dissolved at this temperature for 8h ~ 8.5h, and then degassed at a constant temperature of 60°C ~ 70°C to obtain a casting liquid; the casting liquid is coated on a glass mold adapted to the extraction head 20 in Example 1, and allowed to stand at room temperature for 15s ~ 30s for pre-forming, and then placed in a water bath to solidify into a film, and then washed with deionized water several times, and then soaked, and then dried at 35°C ~ 45°C to obtain a microporous base membrane.

[0184] Preparation of nickel ion imprinted extraction membrane: prepare the raw materials according to the ratio of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide in the proportion of 1mmol﹕1mmol﹕5mmol﹕20mmol﹕50mg﹕12mL, then add nickel acetate, diphenylthioazocarbonyl hydrazide and 2-(diethylamino)ethyl methacrylate into dimethyl sulfoxide, mix and dissolve, and shake to mix (for example, shake for 6h to 10h); then add styrene and 2,2'-diazoisobutyronitrile in turn, mix by ultrasound (for example, ultrasound for 20min to 50min), and form a prepolymer solution.

[0185] The prepared microporous base membrane is immersed in the prepolymer solution for a first period of time (for example, 20s to 30s), taken out and polymerized at a polymerization temperature of 55°C to 65°C for a second period of time (for example, 20h to 30h), and then ultrasonically washed with an ethanol / acetic acid mixed solution (volume ratio 8:1) and dried to obtain a nickel ion imprinted extraction membrane.

[0186] The thickness of the nickel ion imprinted extraction membrane obtained in this Example 3 is 0.2 mm.

[0187] The nickel ion imprinted extraction membrane prepared in Example 3 was used to conduct the following experiment to evaluate the extraction and enrichment efficiency of the nickel ion imprinted extraction membrane for common metal ions in water.

[0188] Three groups of water samples were prepared, each containing nickel ions, iron ions, copper ions, zinc ions and aluminum ions commonly found in environmental water. In water sample I, the concentration of the five metal ions was 0.05 mg / L; in water sample II, the concentration of the five metal ions was 0.10 mg / L; in water sample III, the concentration of the five metal ions was 0.20 mg / L.

[0189] The experimental method is as follows: the nickel ion imprinting extraction device of Example 1 is used, and three groups of water samples of a first preset volume (for example, 200 mL) are sucked into the tube 11 through the sample inlet 112, and then the water samples are discharged at a rate of 20 mL / min through the sample outlet 111, and the effluent (corresponding to effluent I, effluent II and effluent III) are all collected, and then the concentrations of nickel ions, iron ions, copper ions, zinc ions and aluminum ions in the effluent are detected by a laboratory inductively coupled plasma mass spectrometer, so as to reversely calculate the enrichment and adsorption efficiency of nickel ions, iron ions, copper ions, zinc ions and aluminum ions in the three groups of water samples by the nickel ion imprinting extraction membrane. The experimental results are shown in Tables 1 to 5 below.

[0190] Table 1

[0191]

[0192]

[0193] Table 2

[0194] Discharge Discharge I Discharge II Discharge III Iron ion concentration mg / L 0.04826 0.09227 0.18942 Iron ion enrichment and adsorption efficiency 3.5％ 7.7％ 5.3％

[0195] Table 3

[0196] Discharge Discharge I Discharge II Discharge III Copper ion concentration mg / L 0.04789 0.09243 0.18424 Copper ion enrichment adsorption efficiency 4.2％ 7.6％ 7.9％

[0197] Table 4

[0198] Discharge Discharge I Discharge II Discharge III Zinc ion concentration mg / L 0.04906 0.09547 0.19318 Zinc ion enrichment adsorption efficiency 1.9％ 4.5％ 3.4％

[0199] Table 5

[0200] Discharge Discharge I Discharge II Discharge III Aluminum ion concentration mg / L 0.04711 0.09472 0.18618 Aluminum ion enrichment adsorption efficiency 5.8％ 5.3％ 6.9％

[0201] The experimental results show that the nickel ion imprinted extraction membrane prepared in Example 3 has an enrichment and adsorption efficiency of more than 90% for nickel ions in the three groups of experimental water samples, and an enrichment and adsorption efficiency of less than 8% for four common metal ions in water, namely iron ions, copper ions, zinc ions and aluminum ions.

[0202] At the same time, the same nickel ion imprinted extraction membrane was subjected to repeated enrichment / elution tests such as enrichment extraction-elution, re-enrichment extraction-elution, and the results showed that after 8 cycles, the enrichment and adsorption efficiency of the imprinted extraction membrane for nickel ions in water did not change significantly, indicating that the imprinted extraction membrane has good stability and reusability.

[0203] It can be seen that the nickel ion imprinted extraction membrane has specific selectivity and has a strong enrichment and adsorption capacity for nickel ions in water, but has a poor enrichment and adsorption capacity for common metal ions in water such as iron, aluminum, copper, zinc, lead, and cadmium. Therefore, when using the nickel ion imprinted extraction membrane to enrich nickel ions in water, it can also effectively eliminate the interference of other metal ions, that is, while purifying the water sample, it effectively extracts and adsorbs the nickel ions in the water sample, thereby further improving the accuracy of nickel ion detection in water.

[0204] Example 4 Nickel ion detection method in water

[0205] A method for detecting nickel ions in water comprises the following steps:

[0206] Enriching nickel ions in the water sample to be tested: using the nickel ion imprinting extraction device of Example 1 (taking the volume of the tube 11 as 200 mL as an example), the extraction head 20 is covered with a nickel ion imprinting extraction membrane 30; a first preset volume of the water sample to be tested is drawn into the tube 11 through the inlet 112, and then the water sample to be tested is discharged through the outlet 111 at a rate of 15 to 25 mL / min, thereby enriching the nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane 30.

[0207] Elution of nickel ions on the nickel ion imprinted extraction membrane 30: A second preset volume (20 mL) of eluent is drawn into the tube 11 through the sample inlet 112 of the nickel ion imprinted extraction device, and then the eluent is discharged at a rate of 4 to 6 mL / min through the sample outlet 111. The eluent elutes the nickel ions on the nickel ion imprinted extraction membrane 30 when flowing through it, and the eluted nickel ions flow out of the tube 11 with the eluent to obtain an eluent. The eluent includes a sodium acetate solution (with a concentration of 1 mol / L) and acetic acid, and the volume ratio of sodium acetate to acetic acid is 1:1.

[0208] Color development phase change: add 1 mL of 1.5 g / L N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide color developer solution and 1 mL of 12 g / L magnesium sulfate solution to the eluent, shake and mix, then add a third preset volume (10 mL) of n-butanol, shake and mix, stand and separate, and obtain the upper organic phase as the sample to be tested. The synthesis of N-ethyl-3-carbazole carboxaldehyde-3-thiosemicarbazide color developer can be found in the above-mentioned related content, which will not be repeated here.

[0209] The absorbance of the sample to be tested is measured by a spectrophotometer to obtain the sample absorbance value of the sample to be tested; the sample nickel ion mass concentration corresponding to the sample absorbance value is obtained according to the linear equation C=0.4453A+0.0027 of the absorbance-nickel ion mass concentration standard curve; and the nickel ion mass concentration in the water sample to be tested is determined according to ρ=C / f.

[0210] In this Example 4, the prepared standard solution is used as a water sample to carry out a spike recovery test to illustrate the accuracy of nickel ion detection in water using the nickel ion imprinting extraction device of the disclosed embodiment.

[0211] Two groups of basic water samples were taken, with background values ​​of nickel ions of 0.00 mg / L (marked as water sample Ⅰ) and 0.10 mg / L (marked as water sample Ⅱ), and spiked values ​​of 0.05 mg / L, 0.10 mg / L and 0.40 mg / L, respectively. The nickel ion concentration of water sample Ⅰ was adjusted to 0.05 mg / L (water sample Ⅰ-1), 0.10 mg / L (water sample Ⅰ-2) and 0.40 mg / L (water sample Ⅰ-3), respectively; the nickel ion concentration of water sample Ⅱ was adjusted to 0.15 mg / L (water sample Ⅱ-1), 0.20 mg / L (water sample Ⅱ-2) and 0.50 mg / L (water sample Ⅱ-3), respectively.

[0212] The nickel ion concentration in water sample I-1, water sample I-2, water sample I-3, water sample II-1, water sample II-2 and water sample II-3 was detected by the nickel ion detection method of Example 4, and the measurement results are shown in Table 6. Each water sample was measured 5 times in parallel and the average value was taken.

[0213] Table 6

[0214]

[0215] It can be seen that the spiked recovery rates are more than 90%, and the spiked recovery results meet the requirements of relevant national and industry standards and specifications. The method for detecting nickel ions in water of the disclosed embodiment has high accuracy.

[0216] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A nickel ion imprinting extraction device, characterized in that: include: The sampling assembly comprises a tube and a push-pull rod, wherein the push-pull rod is slidably inserted into the tube from the first end of the tube, and the second end of the tube is provided with a sample outlet and a sample inlet; pulling the push-pull rod enables the fluid to enter the tube from the sample inlet, and pushing the push-pull rod enables the fluid in the tube to flow out from the sample outlet; the second port of the tube serves as the sample outlet, a through hole is provided on the side wall near the second port, and a liquid inlet pipe is connected to the through hole, and the end of the liquid inlet pipe serves as the sample inlet; The extraction head is provided with a liquid inlet and a liquid outlet, a flow channel is formed between the liquid inlet and the liquid outlet, and the liquid inlet is connected with the sample outlet of the tube; wherein a nickel ion imprinted extraction membrane is provided in the flow channel of the extraction head, so that when the push-pull rod is pushed, the fluid in the tube flows out from the sample outlet to the extraction head and flows through the nickel ion imprinted extraction membrane before flowing out; A heating assembly, used for heating the extraction head to heat the fluid flowing through the extraction head and / or to heat the nickel ion imprinted extraction membrane disposed in the extraction head; and A nickel ion imprinted extraction membrane adapted to the flow channel of the extraction head, capable of being adapted to be arranged in the extraction head and covering the flow channel of the extraction head; wherein the nickel ion imprinted extraction membrane comprises a microporous base membrane and an imprinted polymer loaded on the microporous base membrane; wherein the imprinted polymer is obtained by immersing an imprinted prepolymer solution in the microporous base membrane and polymerizing it at a polymerization temperature; and the thickness of the nickel ion imprinted extraction membrane is 0.1 mm to 0.5 mm; and the porosity of the microporous base membrane is 70% to 85%; The microporous base membrane is obtained by applying a casting solution to a mold and solidifying it; wherein the casting solution comprises a vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyoxyethylene, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10:1-3:5-10:1-3:0.1-0.5:25-30:50-60; The prepolymer solution includes nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide, and the usage ratios of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are 1mmol﹕1mmol﹕3-6mmol﹕15-25mmol﹕40-60mg﹕10-20mL respectively; and the prepolymer solution is obtained by mixing and evenly mixing the components according to their respective usage amounts.

2. The nickel ion imprinting extraction device according to claim 1, characterized in that: The extraction head further comprises: A support structure is arranged in the flow channel; a nickel ion imprinted extraction membrane is arranged on the support surface of the support structure on the liquid inlet side of the extraction head; The flow passage of the extraction head includes a connected straight section and a necked section; the port of the straight section serves as a liquid inlet, and the port of the necked section serves as a liquid outlet; the support structure is arranged at the connection between the straight section and the necked section.

3. The nickel ion imprinting extraction device according to claim 2, characterized in that: The extraction head further comprises: The rubber ring is arranged on the supporting surface of the supporting structure on the liquid inlet side to clamp the edge of the nickel ion imprinting extraction membrane.

4. The nickel ion imprinting extraction device according to claim 1, characterized in that: The heating assembly includes a heating part, which is arranged on the extraction head; the heating part includes a heating sleeve, which has a heating cavity adapted to the shape of the extraction head; when the extraction head needs to be heated, the heating sleeve is placed on the outside of the extraction head and the heating sleeve is started for heating; or, the heating part includes a heating core, which is buried in the side wall of the extraction head and / or the heating core is buried in the supporting structure of the extraction head.

5. The nickel ion imprinting extraction device according to claim 4, characterized in that: The heating assembly also includes a heating power supply electrically connected to the heating part to provide voltage to the heating part to generate heat.

6. The nickel ion imprinting extraction device according to claim 5, characterized in that: The heating assembly also includes a controller for controlling the heating power supply to supply power to the heating part when the ambient temperature is lower than the set temperature.

7. The nickel ion imprinting extraction device according to claim 6, characterized in that: The controller includes a temperature controller, and the temperature control terminal of the temperature controller is connected to the electrical connection line between the heating part and the heating power supply; when the ambient temperature is lower than the set temperature, the temperature control terminal is turned on, so that the heating power supply supplies power to the heating part.

8. The nickel ion imprinting extraction device according to claim 1, characterized in that: The casting solution comprises vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyoxyethylene, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate in a weight ratio of 10:2:7:2:0.2:27:52; The prepolymer solution includes nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide, and the usage ratios of nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are 1mmol﹕1mmol﹕4-5mmol﹕18-22mmol﹕45-55mg﹕10-15mL respectively.

9. The nickel ion imprinting extraction device according to any one of claims 1 to 3, characterized in that: The microporous base membrane is prepared by the following steps: vinylidene fluoride-trifluoroethylene copolymer, polyphenylene sulfone, polyethylene oxide, 1-methyl-2-pyrrolidone, cellulose acetate, dimethyl sulfoxide and tributyl phosphate are mixed in a weight ratio of 10:1-3:5-10:1-3:0.1-0.5:25-30:50-60, and then heated to dissolve, and then degassed to obtain a casting liquid; the casting liquid is coated on a mold, and after pre-forming, it is placed in a water bath to solidify into a membrane, and then washed and dried to obtain a microporous base membrane; The nickel ion imprinted extraction membrane is prepared by the following steps: nickel acetate, diphenylthioazocarbonyl hydrazide, 2-(diethylamino)ethyl methacrylate, styrene, 2,2'-diazoisobutyronitrile and dimethyl sulfoxide are mixed in a ratio of 1mmol: 1mmol: 3-6mmol: 15-25mmol: 40-60mg: 10-20mL to form a prepolymer solution; then the microporous base membrane is immersed in the prepolymer solution for a first period of time, taken out and polymerized at a polymerization temperature for a second period of time, washed and dried to obtain a nickel ion imprinted extraction membrane.

10. The nickel ion imprinting extraction device according to claim 9, characterized in that: Heat to dissolve, then degas, to obtain a casting solution; including: using a step-by-step heating method to dissolve and mix, then degas at a constant temperature to obtain the corresponding casting solution; wherein the temperature range in the step-by-step heating method is controlled at 50°C to 80°C, and the step-by-step heating and dissolving is divided into two, three or more stages.

11. The nickel ion imprinting extraction device according to claim 10, characterized in that: The step-wise heating method includes heating at 50°C to 60°C for 30 min to 40 min, then heating to 70°C to 80°C and dissolving at this temperature for 8 h to 8.5 h.

12. The nickel ion imprinting extraction device according to claim 9, characterized in that: The casting liquid is coated on the mold, and after preforming, it is placed in a water bath to solidify into a membrane, and then washed and dried to obtain a microporous base membrane; comprising: The casting liquid is coated on the mold and sequentially solidified at room temperature and solidified in a water bath, then washed and dried to obtain a microporous base membrane; wherein, the room temperature solidification method is to place the mold coated with the casting liquid at room temperature for 15s to 30s for pre-solidification; the water bath solidification method is to immerse the pre-solidified mold in deionized water to form a film in a water bath.

13. A method for detecting nickel ions in water, characterized in that: include: Enriching nickel ions in a water sample to be tested: using the nickel ion imprinting extraction device as described in any one of claims 1 to 12, sucking a first preset volume of the water sample to be tested into a tube through the sample inlet, and then discharging the water sample to be tested through the sample outlet, thereby enriching nickel ions in the water sample to be tested on the nickel ion imprinting extraction membrane; the discharge rate of the water sample to be tested through the sample outlet (111) is 15 to 25 mL / min; the first preset volume is the volume of the tube of the nickel ion imprinting extraction device; Eluting nickel ions from the nickel ion imprinted extraction membrane: a second preset volume of eluent is sucked into the tube through the sample inlet of the nickel ion imprinted extraction device, and then the eluent is discharged through the sample outlet, and the nickel ions on the nickel ion imprinted extraction membrane are eluted when the eluent flows through the nickel ion imprinted extraction membrane, and the eluted nickel ions flow out of the tube with the eluent to obtain the eluent; the discharge rate of the eluent through the sample outlet is 4 to 6 mL / min; the second preset volume is one fifth to one tenth of the volume of the tube; Color development phase change: add a color developer solution and a magnesium sulfate solution to the eluent, shake and mix, then add a third preset volume of n-butanol, shake and mix, let stand to separate, and obtain the upper organic phase as the test sample; the volume ratio of the color developer solution to the magnesium sulfate solution is 1:1; the volume ratio of the color developer solution to the eluent is 1:15-25; the ratio of the second preset volume to the third preset volume is 1-3:1; The sample to be tested is subjected to absorbance measurement or colorimetric visual measurement, and the nickel ion mass concentration in the water sample to be tested is determined according to an absorbance-nickel ion mass concentration standard curve or a standard colorimetric card / tube; The linear equation of the absorbance-nickel ion mass concentration standard curve is C=0.4453A+0.0027, where A is the absorbance and C is the mass concentration, mg / L.

14. The method for detecting nickel ions in water according to claim 13, characterized in that: The absorbance of the sample to be tested is measured, and the mass concentration of nickel ions in the water sample to be tested is determined according to a standard curve of absorbance-nickel ion mass concentration; comprising: Using a spectrophotometer to measure the absorbance of the sample to be tested, and obtaining the sample absorbance value of the sample to be tested; According to the absorbance-nickel ion mass concentration standard curve, the nickel ion mass concentration of the sample corresponding to the absorbance value of the sample is obtained; According to ρ=C / f, determine the mass concentration of nickel ions in the water sample to be tested; Wherein, ρ is the nickel ion mass concentration in the water sample to be tested, mg / L; C is the nickel ion mass concentration of the sample, mg / L; f is the dilution multiple of the volume of the water sample to be tested relative to the standard volume, where the standard volume is the volume of the standard solution in the process of drawing the absorbance-nickel ion mass concentration standard curve, which is a constant.

15. The method for detecting nickel ions in water according to claim 14, characterized in that: The method for drawing the absorbance-nickel ion mass concentration standard curve comprises: Prepare standard solutions with a series of concentrations; Enriching nickel ions: using the nickel ion imprinting extraction device as described in any one of claims 1 to 12, sucking a standard volume of a standard solution into the tube through the inlet, and then discharging the standard solution through the outlet, thereby enriching the nickel ions in the standard solution on the nickel ion imprinting extraction membrane; Eluting nickel ions: a second preset volume of eluent is sucked into the tube through the inlet of the nickel ion imprinting extraction device, and then the eluent is discharged through the outlet. When the eluent flows through the nickel ion imprinting extraction membrane, the nickel ions on the membrane are eluted, and the eluted nickel ions flow out of the tube with the eluent to obtain the eluent; The series of standard solutions are subjected to the operations of enriching nickel ions and eluting nickel ions to obtain corresponding series of standard eluents; Adding a colorimetric agent solution and a magnesium sulfate solution to the series of standard eluents respectively, shaking and mixing, and then adding a third preset volume of n-butanol respectively, shaking and mixing, standing and stratifying, obtaining an upper organic phase, and obtaining a series of standard test samples; The series of standard test samples are poured into colorimetric tubes respectively, and placed in the colorimetric wells in turn for absorbance measurement to obtain the absorbance of the corresponding series of standard solutions; then a standard curve is drawn with the absorbance of the series of standard solutions as the horizontal axis and the nickel ion concentration of the series of standard solutions as the vertical axis to obtain an absorbance-nickel ion mass concentration standard curve.

16. A nickel ion detection kit in water, characterized in that: include: The nickel ion imprinted extraction device according to any one of claims 1 to 12 is capable of sucking a water sample to be tested through a sample inlet and then discharging the water sample to be tested through a sample outlet, thereby enriching nickel ions in the water sample to be tested on a nickel ion imprinted extraction membrane; The reagent combination includes an eluent, a color developer solution, a magnesium sulfate solution and n-butanol. The eluent is used to elute the nickel ions enriched on the nickel ion imprinting extraction membrane of the nickel ion imprinting extraction device to obtain an eluent. The color developer solution, the magnesium sulfate solution and the n-butanol solution are added to the eluent in sequence to obtain a test sample containing nickel ions.

17. The nickel ion detection kit in water according to claim 16, characterized in that: The developer solution comprises an N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide solution; wherein the N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide is synthesized by the following method: dissolving N-ethylcarbazole-3-formaldehyde in ethanol to obtain solution A, wherein the ratio of N-ethylcarbazole-3-formaldehyde to ethanol is 2g-4g:100mL; dissolving hydrazine-carbon sulfamide in the ethanol solution to obtain solution B, wherein the ratio of hydrazine-carbon sulfamide to ethanol solution is 5g-8g:100mL; mixing solution A and solution B evenly, refluxing in a water bath for reaction, and then standing at room temperature to precipitate; then filtering, washing, and drying to obtain a crude product; and recrystallizing the crude product to obtain N-ethyl-3-carbazole formaldehyde-3-thiosemicarbazide.

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