Water body sampling device based on evaporation driving, sampling method and water body detection method

Abstract

The invention belongs to the technical field of water body sampling devices, and particularly relates to a water body sampling device based on evaporation driving, a sampling method and a water body detection method. A water body sampling device based on evaporation driving is adopted to sample a water body to be detected, the water body sampling device based on evaporation driving comprises a water inlet end and an evaporation end which are communicated through a water guide pipe, and a liquid sampler is arranged between the water inlet end and the evaporation end; the water inlet end is put into a water body to be detected, the water body to be detected sequentially passes through the water inlet end, the liquid sampler and the evaporation end to be continuously evaporated under the driving of the evaporation force of the evaporation end, and substances to be detected in the water body to be detected are continuously collected by the liquid sampler. Real-time active sampling is achieved under the action of evaporation force, and the defect that a traditional adsorption type sampling device needs a large amount of energy to provide sampling power is overcome. And meanwhile, a passive sampler is combined as an adsorption device, so that good stability and reutilization effect are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of monitoring devices for heavy metal pollution in water bodies, and particularly relates to a water body sampling device, a sampling method, and a water body detection method based on evaporation drive. Background Art

[0002] The presence of heavy metal ions pollution and organic pollutants in the aquatic environment is a concern because their long-term effects on aquatic organisms and human health are unknown. Sample collection is the first step in environmental analysis. Currently, active sampling methods have disadvantages such as being time-consuming and laborious, unstable, prone to component changes, and requiring complex pretreatment steps. The emergence of some new sampling devices relying on batteries as the energy supply has simplified the sampling process. For example, the continuous low concentration level (CLAM) sampler has been applied to the monitoring of pesticides and pesticide degradation products in urban runoff. However, due to the limited energy provided by the battery, the deployment time of active sampling is usually short. Therefore, in the latest research, the energy supply of active samplers is an urgent problem to be solved. Summary of the Invention

[0003] The purpose of the present invention is to provide a water body sampling device, a sampling method, and a water body detection method based on evaporation drive, which utilize the action of evaporation force to achieve real-time active sampling without consuming electric energy, thereby improving the sampling rate and avoiding the limitations of traditional technology disadvantages.

[0004] To achieve the above purpose, the present invention provides a water body sampling method based on evaporation drive, including: using a water body sampling device based on evaporation drive to sample the water body to be measured, the water body sampling device based on evaporation drive includes a water inlet end and an evaporation end connected by a water conduit, and a liquid sampler is provided between the water inlet end and the evaporation end;

[0005] Put the water inlet end into the water body to be measured, and under the driving of the evaporation force at the evaporation end, the water body to be measured is continuously evaporated through the water inlet end, the liquid sampler, and the evaporation end in sequence, and the substances to be measured in the water body to be measured are continuously collected by the liquid sampler.

[0006] Further, the liquid sampler includes an adsorbent filler and a first porous sieve plate and a second porous sieve plate arranged on both sides of the adsorbent filler;

[0007] Preferably, a first polytetrafluoroethylene filter membrane and a second polytetrafluoroethylene filter membrane are respectively provided on the sides of the first porous sieve plate and the second porous sieve plate away from the adsorbent filler, and a limiting ring and a gland are sequentially arranged above the first polytetrafluoroethylene filter membrane.

[0008] Furthermore, the evaporation end includes an evaporation component and a floating component, and the evaporation component is fixed on the floating component; the evaporation component includes an evaporation element and a central tube, the central tube is connected to the liquid sampler through the water guide pipe, and one end of the evaporation element is connected to the central tube for sucking and evaporating the water in the central tube upward.

[0009] Furthermore, the evaporation element is sponge, towel or hydrogel; a large collector is also provided between the central tube and the water guide pipe;

[0010] Preferably, the evaporation component further includes a top plate arranged above the evaporation element.

[0011] Furthermore, the floating component includes a floating plate and floating blocks, the floating blocks are arranged at the bottom of the floating plate, and the central tube is fixed on the floating plate;

[0012] The floating blocks are polyurethane foam, EPE rod, aerogel or wood material.

[0013] Furthermore, a replaceable membrane type needle filter is provided at the water inlet end; a glass fiber membrane is arranged in the replaceable membrane type needle filter for intercepting non-dissolved heavy metals.

[0014] The present invention also provides a water body sampling device based on evaporation drive, including a water inlet end and an evaporation end connected through a water guide pipe, and a liquid sampler is arranged between the water inlet end and the evaporation end; the evaporation end includes an evaporation component and a floating component to float on the water surface through the floating component;

[0015] The evaporation component is fixed on the floating component; the evaporation component includes an evaporation element and a central tube, the central tube is fixed on the floating component, and the lower end is connected to the water guide pipe, and the upper end is connected to the evaporation element; a support rod is arranged on the floating component for fixedly arranging a top plate above the floating component, and the evaporation element is located between the floating component and the top plate.

[0016] Furthermore, the liquid sampler includes an adsorbent filler and a first porous sieve plate and a second porous sieve plate arranged on both sides of the adsorbent filler;

[0017] Preferably, a first polytetrafluoroethylene filter membrane and a second polytetrafluoroethylene filter membrane are respectively arranged on the sides of the first porous sieve plate and the second porous sieve plate away from the adsorbent filler, and a limiting ring and a gland are sequentially arranged above the first polytetrafluoroethylene filter membrane;

[0018] A replaceable membrane type needle filter is provided at the water inlet end; a glass fiber membrane is arranged in the replaceable membrane type needle filter for intercepting non-dissolved heavy metals.

[0019] The present invention also provides a water body detection method based on evaporation drive, which includes the following steps:

[0020] S1. Sampling the water body to be measured by using the said water body sampling method;

[0021] S2. After the sampling is completed, remove the said liquid sampler, wash and elute the liquid sampler, collect the eluate, and then test the content of the substance to be measured in the eluate, thus obtaining the content of the substance to be measured in the water body to be measured.

[0022] Furthermore, the substance to be measured is a heavy metal or an organic substance; when the substance to be measured is a heavy metal, the adsorbent in the said liquid sampler adopts Chelex 100 sodium-type chelating resin, and when the substance to be measured is an organic substance, the adsorbent adopts divinyl / N-vinylpyrrolidone copolymer filler.

[0023] Furthermore, before sampling the water body to be measured, first exhaust the air from the water body sampling device based on evaporation drive.

[0024] Furthermore, the washing and elution include: loading the said liquid sampler into a filtration adapter, one end of the filtration adapter is connected to a sample bottle, and the other end is connected to a peristaltic pump; during washing, the sample bottle is filled with water, and the water is pumped through the peristaltic pump to wash the substance to be measured adsorbed by the liquid sampler; during elution, the sample bottle is filled with 1wt%-8wt% HNO3, and the nitric acid is pumped through the peristaltic pump to elute the substance to be measured adsorbed by the liquid sampler.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The evaporation-driven sampling device provided by the present invention combines an evaporation component and a liquid sampler, and uses the action of evaporation force to achieve real-time continuous active sampling, which not only improves the sampling rate but also overcomes the drawback that a large amount of energy is required by traditional adsorption-type sampling devices to provide sampling power.

[0027] (2) The internal cavity assembly structure is adopted inside the liquid sampler of the present invention to avoid adsorption deviation of target pollutants caused by environmental factors, and at the same time, the design of a hollow cylinder is adopted to reduce water body resistance. The adsorbent filler is pressed by a porous sieve plate, and a layer of polytetrafluoroethylene filter membrane needs to be placed again to avoid pollution by impurities in the wild water body. The microporous structure material of the porous sieve plate can attach a heavy metal film on its surface, and its toxicity can prevent the formation of a microbial film, thereby avoiding the influence of the microbial film on the adsorption efficiency.

[0028] (3) The device has a simple structure, low cost, and can be reused; it can realize the synchronous monitoring of pollutants at multiple points in a large range, and can also realize the synchronous and stable determination of multi-index pollutants such as common heavy metal ions and organic substances. It has a high determination capacity and is not easily affected by the environment. Combined with a liquid sampler, the device has good stability and reuse effect. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the evaporation-driven sampling device of the present invention;

[0030] Figure 2 It is a schematic structural diagram of the adoption state of the evaporation-driven sampling device of the present invention;

[0031] Figure 3 It is a schematic internal structure diagram of the liquid sampler;

[0032] Figure 4 It is a schematic structural diagram of the elution device;

[0033] Figure 5 It is an assembled schematic diagram of the air exhaust device of the liquid sampler;

[0034] Figure 6 It is a trend diagram of evaporation-driven sampling with the number of experimental days as the abscissa and the sampling amount of metal ions in the sampler as the ordinate in Example 1;

[0035] Figure 7 It is a trend diagram of evaporation-driven sampling with the evaporation volume as the abscissa and the sampling amount of metal ions in the sampler as the ordinate in Example 2;

[0036] Figure 8 It is the concentration test result of different metal ions for 7 days of the present invention.

[0037] Explanation of the reference numerals:

[0038] 1 - Top plate; 2 - Floating plate; 3 - Central tube; 4 - Large collector; 5 - Floating block; 6 - Liquid sampler; 7 - Replaceable membrane needle filter; 8 - Water guide tube; 6-1 - First porous sieve plate; 6-2 - Second porous sieve plate; 6-3 - Limit ring; 6-4 - Pressure cover; 6-5 - O-ring; 9 - Spout collector; 10 - Adapter; 11 - Filter adapter; 12 - Independent collector; 13 - Sampling bottle; 14 - Hydrophilic sieve plate; 15 - Conducting hose; 16 - Peristaltic pump; 17 - Unsupported PTFE coating bracket; 18 - Buckle. Detailed Embodiments

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Please refer to Figure 1-3 , the present invention provides a water body sampling method based on evaporation drive, including: using a water body sampling device based on evaporation drive to sample a water body to be measured, the water body sampling device based on evaporation drive includes a water inlet end and an evaporation end connected through a water guide pipe, and a liquid sampler 6 is arranged between the water inlet end and the evaporation end;

[0041] Put the water inlet end into the water body to be measured. Under the driving of the evaporation force at the evaporation end, the water body to be measured is continuously evaporated through the water inlet end, the liquid sampler 6 and the evaporation end in sequence, so that the substances to be measured in the water body to be measured are continuously collected by the liquid sampler.

[0042] The evaporation end includes an evaporation component and a floating component, and the evaporation component is fixed on the floating component; the evaporation component includes an evaporation element and a central tube 3, the central tube 3 is connected to the liquid sampler 6 through the water guide pipe 8, and one end of the evaporation element is connected to the central tube 3 for sucking and evaporating the water in the central tube 3 upward.

[0043] The present invention also provides a water body sampling device based on evaporation drive, including a floating component, an evaporation component and a liquid sampler 6, the evaporation component is connected to one end of the liquid sampler 6 through a water guide pipe 8; the other end of the liquid sampler 6 is connected to the water body to be measured through a water guide pipe 8;

[0044] The evaporation component is fixed on the floating component to float on the water surface through the floating component. The water in the water body to be measured is evaporated upward through the liquid sampler 6 under the action of the evaporation component, so as to adsorb the substances to be measured in the water body to be measured into the liquid sampler 6.

[0045] Specifically, the liquid sampler 6 includes a sleeve and a first porous sieve plate 6-1 and a second porous sieve plate 6-2 which are placed inside the sleeve from top to bottom. Among them, a first polytetrafluoroethylene filter membrane is placed above the first porous sieve plate 6-1, an adsorbent filler is placed between the first porous sieve plate 6-1 and the second porous sieve plate 6-2, and a second polytetrafluoroethylene filter membrane is placed below the second porous sieve plate 6-2.

[0046] Refer to Figure 3, the internal structure of the liquid sampler 6 adopts an inner cavity type assembly structure to avoid adsorption deviation of target pollutants caused by environmental factors, and at the same time adopts the design of a hollow cylinder to reduce water resistance. In the present invention, during actual use, first place a layer of 0.45 μm polytetrafluoroethylene filter membrane at the bottom of the sleeve; then place the second porous sieve plate 6-2, and then place the required adsorbent filler. Different adsorbent fillers can be selected according to different pollutants. In the experimental stage of the sampling system of the present invention, analytical grade Chelex 100 sodium chelating resin (200-400 mesh) is selected to adsorb heavy metal ions, and HLB (divinyl / N-vinylpyrrolidone, average particle size 40-60 μm) is selected to adsorb organic pollutants as the adsorbent filler, and good adsorption effects can be achieved. A layer of porous sieve plate, that is, the first porous sieve plate 6-1, still needs to be covered above the adsorbent filler to press the adsorbent filler; finally, a layer of 0.45 μm polytetrafluoroethylene filter membrane needs to be placed again. The two outermost filter membranes are used to protect the adsorbent filler, thereby avoiding contamination of impurities in the wild water body. The upper part is fixed with a limit ring 6-3 to ensure that the adsorbent filler will not be washed away by the water flow, and also enables the built-in adsorption filler to stably adsorb the analytes in the environment. Finally, fix the gland 6-4 with a matching tool wrench sleeve to complete the assembly of the liquid sampler 6.

[0047] Specifically, the porous sieve plate of the liquid sampler 6 is made of a microporous structure material for filtration. Different from the permeable film, the microporous structure material can attach a heavy metal film to its surface, and prevent the formation of a microbial film with its toxicity, thereby avoiding its influence on the adsorption efficiency. Select two porous sieve plates and distribute them on the upper and lower sides of the adsorbent filler respectively to support the adsorbent. An additional layer of 0.45 μm polytetrafluoroethylene filter membrane is added outside the sieve plate to protect the adsorbent filler. An additional limit ring is used to keep the adsorbent in a tight state and prevent it from flowing away with the water flow.

[0048] The evaporation assembly includes an evaporation element and a central tube 3. The central tube 3 is fixed on the floating assembly, and its lower end is connected to the water guide tube 8, and its upper end is connected to the evaporation element, and is used to suck and evaporate the water in the central tube 3 upward. A large collector 4 is also provided between the central tube 3 and the water guide tube 8. The evaporation element can be a sponge, a towel or a hydrogel, etc., and a photothermal material can also be compounded in such water-absorbing materials to promote water evaporation by photothermal conversion. The large collector 4 connects the central tube 3 and the water guide tube 8, so that the water flow can be stored and evaporated in the central tube 3; the large collector 4 is made of pp material and is overall in a funnel shape. The central concave part of its upper part is connected to the central tube 3, and the lower part is in a pointed shape and is connected to the liquid sampler 6 through the water guide tube 8. To prevent the water guide tube 8 from falling off, the outside of its pointed part is threaded and fixed with a nut. There is a hole in the middle of the nut, and the water guide tube 8 can pass through the center; there are M8 threaded holes around the central concave part, and the large collector 4 and the central tube 3 are fixed on the floating plate 2 through M8 threaded posts.

[0049] The evaporation assembly further includes a top plate 1 disposed above the evaporation element, which is used to fix the evaporation element and prevent rainwater from entering and affecting the evaporation of the evaporation assembly and the sampling result in the liquid sampler 6. The side walls of the evaporation element are all in an exposed state to maximize the evaporation area, so that moisture evaporates from the side under the action of wind at the sampling site and the like.

[0050] The floating assembly includes a floating plate 2 and a floating block 5. The floating block 5 is disposed at the bottom of the floating plate 2, and the central tube 3 is fixed to the floating plate 2. The floating block 5 is made of polyurethane foam, pearl cotton rod, aerogel, wood material, etc. The floating plate 2 can float on the water surface through the floating block 5, and thus the evaporation element floats on the water surface.

[0051] The liquid sampler 6 is disposed inside the spout collector 9. The spout collector 9 and the replaceable membrane needle filter 7 are provided with an inlet and an outlet. The central tube 3 communicates with the outlet of the spout collector 9 through a water conduit 8. The outlet of the replaceable membrane needle filter 7 is connected to the inlet of the spout collector 9 through a water conduit 8 (such as a silica gel tube). The inlet of the replaceable membrane needle filter 7 is connected to the external liquid environment. A glass fiber membrane is placed inside the replaceable membrane needle filter 7 and fixed with a rubber ring.

[0052] See Figure 5 , before the liquid sampling system starts to load samples, it is necessary to perform an air exhaust treatment on the assembled liquid sampler 6. In this embodiment, a spout collector 9 is nested at the top and bottom of the liquid sampler 6 respectively. The water outlet of the spout collector 9 near the top of the liquid sampler 6 (the gland 6-4 end) is connected to a 10 mL syringe (without the needle) adapter 10; the water outlet of the spout collector 9 near the bottom of the liquid sampler 6 (the filter membrane end) is placed in pure water. Use the syringe to start pumping pure water. When pure water is sucked into the syringe, stop pumping and remove the syringe. Then take out the liquid sampler 6 nested in the two spout collectors 9 and place it in pure water to complete the air exhaust step.

[0053] In this embodiment, the evaporation element is selected as a towel. The towel is fixed between the floating plate 2 and the top plate 1 through a plurality of towel clips. The central tube 3 is fixed to the floating plate 2, and one end thereof protrudes from the upper part of the floating plate 2 and is connected to the towel. To ensure the connection between the top plate 1 and the towel clip, a groove is provided at the lower part of the top plate 1, and circular magnets are installed in the groove and the towel clip to connect the top plate 1 and the towel clip.

[0054] In the present invention, to ensure the close fit between the floating plate 2 and the central tube 3, a hole is opened in the center of the floating plate 2 and waterproof glue is applied to ensure the close fit between the floating plate 2 and the central tube 3.

[0055] In the present invention, in order to ensure that the central tube 3 and the large-sized collector 4 are nested tightly, a groove is provided at the lower part of the central tube 3, and a large-sized O-ring is installed inside the groove to closely fit the central tube 3 with the external large-sized collector 4. A thread is provided at the lower end of the large-sized collector 4.

[0056] In the present invention, in order to ensure that the liquid sampler 6 and the nozzle collector 9 are nested tightly, grooves are provided on the outer parts of the upper and lower ends of the sleeve, and an O-ring 6-5 is installed inside the groove to closely fit the sleeve with the external nozzle collector 9.

[0057] In the present invention, the floating device can have two installation forms. Assembly method 1: The floating board 2 is not installed with the EPE rod 5. At this time, the floating device is connected to the evaporation bucket in the following way: The floating board 2 is provided with fixed holes, and it is fixed to the evaporation bucket with screw holes by screws.

[0058] Assembly method 2: Floating blocks 5 such as EPE rods or foams are installed on the floating board 2. At this time, the floating device can be directly placed in the outdoor water body to achieve floating. Specifically, the two floating blocks 5 are respectively installed at the two sides of the bottom of the floating board 2. Through the buoyancy of the floating blocks 5, the components above the floating board 2 are all located above the water surface.

[0059] After the evaporation-driven sampling device is arranged in the target water body, due to the action of atmospheric pressure, the water sample first passes through the polytetrafluoroethylene filter membrane and then enters the liquid sampler 6 filled with Chelex100 resin (adsorbent filler), and finally rises to the central tube 3 until it is flush with the external water surface. The water on the towel evaporates in the natural state and continuously absorbs the water in the central tube 3. Therefore, the evaporation-driven sampler can continuously collect water samples. The dissolved heavy metals in the water sample are fixed on the Chelex100 resin filler during this process, and the non-dissolved heavy metals are intercepted by the glass fiber membrane in the replaceable membrane needle filter 7.

[0060] Please refer to Figure 4 , the top of the filtration adapter 11 is connected to the sample loading bottle 13, and the two are connected by a buckle 18. A hydrophilic sieve plate 14 is installed between the filtration adapter 11 and the sample loading bottle 13 to preliminarily filter the inlet water body (a 0.2μm microporous water-based filter membrane can be covered to prevent the hydrophilic sieve plate from floating); the liquid sampler 6 is connected to the inside of the filtration adapter 11, and the lower part is nested in the independent collector 12. Then, the outlet of the independent collector 12 is connected to a conduction hose 15 with an inner diameter of 3mm and a wall thickness of 1mm, and the sample is eluted to the collection container through a peristaltic pump 16. This device is used for the elution process.

[0061] In the following embodiments, the floating part, the nozzle collector, and the liquid sampler in the liquid sampling system are all made of PTFE. As a functional polymer material in the industrial field, PTFE can be used for non-stick coatings to withstand high temperatures and corrosion, and can be applied to various water body environments.

[0062] The present invention will be further described in detail below in conjunction with specific embodiments:

[0063] Field performance and preliminary application of the sampler:

[0064] The evaporation-driven sampler of the present invention is deployed in field waters and simulated waters to collect heavy metals and organic pollutants therein to evaluate its performance in the actual environment.

[0065] The sampling process of the liquid sampling system can select the sampling - measurement process according to the target pollutant to be measured.

[0066] Heavy metals: activation - air discharge - active sampling - membrane removal - rinsing - elution - analysis.

[0067] Example 1

[0068] Example of active sampling of heavy metals (South Lake water);

[0069] This example provides an example of active sampling and analysis of common divalent metal ions in water bodies, which can well characterize the risk of water body pollutants.

[0070] 1.1 Sampling

[0071] Use an organic glass sampler with a capacity of 1 L to continuously collect 5 L of South Lake water, and pay attention to avoiding the use of metal products during the collection process.

[0072] 1.2 Recovery of heavy metals in the water by the sampler

[0073] Instruments and consumables: peristaltic pump BT100-L, pump head DG-6 or DG-12 (6 channels or 12 channels), 3*1 (inner diameter 3 mm, wall thickness 1 mm) or 16# (inner diameter 3.2 mm, wall thickness 1.6 mm) hose, organic glass bucket.

[0074] Use Chelex100 sodium chelating resin (200 - 400 mesh) adsorbent filler to recover divalent metal ions in the water.

[0075] The following steps are carried out in sequence:

[0076] (1) Assemble the liquid sampler: sequentially place a second porous sieve plate (5 μm pore diameter, PP material), 0.5 g of Chelex100 sodium chelating resin, a first porous sieve plate (5 μm pore diameter, PP material), a 0.45 μm polytetrafluoroethylene membrane, and a limit ring inside the sleeve, and finally cover the pressure cap with a wrench sleeve.

[0077] (2) Activation: According to the number of peristaltic pump channels, a corresponding number of active and passive sampling devices can be set up to carry out multi-channel sample enrichment and recovery. In this embodiment, 6 groups of experiments are set up (including 5 groups of parallel experimental groups and one blank experimental group). 10 mL of 0.5 mol / L sodium acetate is added to each of the 6 sample loading bottles 13. To prevent the filter membrane from being damaged, the flow rate of the peristaltic pump is set to 1.5 mL / min. After starting, it is pumped dry to activate the Chelex 100 sodium-type chelating resin.

[0078] (3) Air exhaust: Nest the assembled liquid sampler 6 into two sharp-tip collectors 9. Install a syringe adapter 10 at the water outlet of the sharp-tip collector with the gland. Place the water outlet of the sharp-tip collector at the filter membrane end into pure water. Slowly pull the upper syringe. Stop pulling when pure water enters the syringe. Remove the syringe, adapter 10 and the two sharp-tip collectors 9 at both ends in sequence. Then immerse the liquid sampler in pure water for standby.

[0079] (4) Assemble the evaporation-driven sampling device according to Figure 1 and 2 . During the assembly of this embodiment, 3.2*1.6 (inner diameter 3.2 mm, wall thickness 1.6 mm) is used for connection between each part.

[0080] (5) After the evaporation-driven sampling device is assembled, place it for one night. Observe whether the water surface in the central tube is flush with the water surface in the plexiglass barrel. After the water surface heights are flush, the device can be placed at a suitable position, such as Figure 2 shown.

[0081] (6) Demembraning: After the end of the experimental period, retrieve the device and remove the liquid sampler 6. Use a wrench socket and tweezers to assist in clamping out the polytetrafluoroethylene filter membranes at both ends of the liquid sampler 6, and then reinstall the liquid sampler 6 into the filter adapter 11; after removing the membrane-changeable needle filter 7, use tweezers to assist in putting the fiberglass membrane inside the membrane-changeable needle filter 7 into a 50 mL centrifuge tube, and add 20 mL of 5 wt% HNO3 (for subsequent sample measurement and analysis).

[0082] (7) Rinsing: Add 10 mL of pure water to the filter adapter 11 for each of the 6 experimental groups. Set the flow rate of the peristaltic pump to 1 mL / min. After starting, pump it dry. The liquids drawn out in the above steps are all treated as waste liquid.

[0083] (8) Elution: Add 10 mL of 5 wt% HNO3 to the filter adapter 11 for each of the 6 experimental groups. Set the flow rate of the peristaltic pump to 1 mL / min. After starting, pump it dry to complete the elution, and collect the eluate with a 15 mL centrifuge tube.

[0084] 1.3 Sample measurement and analysis

[0085] The content of heavy metals in the eluate was analyzed by ICP-OES. According to the concentration factor, the concentration of heavy metals in the water body can be calculated.

[0086] 1.4 Result Analysis

[0087] The contents of four metal ions, cadmium, lead, chromium, and copper, in the eluate collected from each test group were detected by ICP-OES. After analysis, the contents of the four heavy metals adsorbed on the liquid sampler were known. According to the concentration factor of this active sampling experiment (sampling volume 500 mL / eluate volume 10 mL) = 50, the heavy metal content in the South Lake water sample of this sampling can be calculated according to the formula: heavy metal content = detected value / concentration factor (Table T1). Furthermore, the next-step analysis and research can be carried out (it has been verified in the present invention that heavy metals can be completely eluted during the above elution process).

[0088] Table 1 Statistical Characteristics of Heavy Metal Contents in South Lake Water (unit μg·L -1 )

[0089]

[0090] From Figure 6 it can be seen that with the increase of sampling days, the amount of adsorbed heavy metals gradually increases, indicating that the evaporation-driven sampling device can self-drive the upward flow of water and enable heavy metals to be adsorbed by the liquid sampler 6.

[0091] Example 2

[0092] Active Sampling Example of Heavy Metals (Spiked Tap Water).

[0093] This example provides an active sampling analysis example of trace divalent metal ions in water bodies, which can well characterize the risks of water body pollutants.

[0094] The active sampling of heavy metals was carried out with reference to the method of Example 1 above. The difference is that the water sample used in Example 1 was the South Lake water sample, while the water sample in this Example 2 was spiked tap water, and the steps were the same as those described in 1.3 - 1.4 of Example 1.

[0095] 2.1 Recovery of Heavy Metals in Water by Sampler

[0096] Instruments and consumables: peristaltic pump BT100-L, pump head DG-6 or DG-12 (6 channels or 12 channels), 3*1 (inner diameter 3 mm, wall thickness 1 mm) or 16# (inner diameter 3.2 mm, wall thickness 1.6 mm) hose, plexiglass barrel, mixed standard curve.

[0097] Chelex100 sodium chelating resin (200 - 400 mesh) adsorbent packing was used to recover divalent metal ions in water.

[0098] The following steps were carried out in sequence:

[0099] (1) Assemble the liquid sampler: sequentially place a 0.45 μm polytetrafluoroethylene filter membrane, a second porous sieve plate (5 μm pore size, PP material), 0.5 g of Chelex 100 sodium chelating resin, a first porous sieve plate (5 μm pore size, PP material), a 0.45 μm polytetrafluoroethylene filter membrane, and a limit ring inside the sleeve. Finally, use a wrench socket to cover the gland with the gland cover.

[0100] (2) Exhaust air: Nest the assembled liquid sampler inside two spout collectors. Install a syringe adapter at the water outlet of the spout collector of the gland cover. Place the water outlet of the spout collector at the filter membrane end into pure water. Slowly pull the upper syringe. Stop pulling when pure water enters the syringe. Remove the syringe, adapter, and the two spout collectors at both ends in sequence. Then soak the liquid sampler in pure water for standby.

[0101] (3) Activation: According to the number of channels of the peristaltic pump, set the corresponding number of active and passive sampling devices to carry out multi-channel sample enrichment and recovery. In this embodiment, 6 groups of experiments are set (including 5 groups of parallel experimental groups and one blank experimental group). Add 10 mL of 0.5 mol / L CH3COONH4 to each of the 6 sample loading bottles 5. To prevent the filter membrane from breaking, set the flow rate of the peristaltic pump to 1.5 mL / min. After starting, pump it dry for activation.

[0102] (4) Assemble the evaporation-driven sampling device according to the figure. During the assembly in this embodiment, connect the various parts with a 3*1 (inner diameter 3 mm, wall thickness 1 mm) or 16# (inner diameter 3.2 mm, wall thickness 1.6 mm) hose.

[0103] (5) After the device is assembled, let it stand for one night. Observe whether the water surface in the central tube is flush with the water surface in the plexiglass barrel. After the water surfaces are flush, the device can be placed in a suitable position.

[0104] (6) Remove the membrane: After the experimental period ends, retrieve the device and remove the liquid sampler 6. Use a wrench socket and tweezers to assist in clamping out the polytetrafluoroethylene filter membranes at both ends of the liquid sampler, and then reinstall the liquid sampler; after removing the replaceable membrane needle filter, use tweezers to assist in putting the fiberglass membrane inside the 9 replaceable membrane needle filter into a 50 mL centrifuge tube, and add 20 mL of 5 wt% HNO3.

[0105] (7) Rinse: Add 10 mL of pure water to the filter adapter for each of the 6 experimental groups. Set the flow rate of the peristaltic pump to 1 mL / min. After starting, pump it dry. The liquids pumped out in the above steps are all treated as waste liquid.

[0106] (8) Elution: 10 mL of 5 wt% HNO3 was added to the filtration adapter for all 6 experimental groups. The peristaltic pump flow rate was set at 1 mL / min. After starting, it was pumped dry to complete the elution, and the eluate was collected with a 15 mL centrifuge tube.

[0107] 2.2 Sample analysis

[0108] ICP-OES was used to analyze the heavy metal content in the eluate. According to the concentration factor, the heavy metal concentration in the water body can be calculated.

[0109] 2.3 Result analysis

[0110] The contents of four metal ions, namely cadmium, lead, manganese, and nickel, in the eluates collected from each experimental group were detected by ICP-OES. After analysis, the contents of the four heavy metals adsorbed on the liquid sampler were known. According to the concentration factor of this active sampling experiment (sampling volume 500 mL / eluate volume 10 mL) = 50, the heavy metal content in the South Lake water sample of this sampling can be calculated according to the formula heavy metal content = detected value / concentration factor (Table T1). Furthermore, the next step of analysis and research can be carried out (it has been verified in the present invention that the above elution process can ensure complete elution of heavy metals).

[0111] Table 2 Statistical characteristics of heavy metal content in South Lake water (unit μg·L -1 )

[0112] Evaporation volume / mL Cd Pb Mn Ni 263.5 1.035 0.46 4.465 2.475 495.2 2.35 0.065 6.295 6.05 685.7 2.6825 0.07 8.55 8.92 917.5 3.525 12.46 9.81 1110.5 5.73 15.0375 14.91

[0113] From Figure 7 it can be seen that with the increase of the evaporation volume, the sampling amount of metal ions in the sampler gradually increases.

[0114] The concentrations of target heavy metals were measured by collecting and simulating contaminated water samples indoors for 7 days (the simulated contaminated water was prepared by adding a heavy metal standard solution of 100 mg / L to tap water, and the theoretical concentration of heavy metal simulation was 20 μg / L, including the free part and the precipitated part), such as Figure 8 . The dots represent the concentrations in the water samples collected simultaneously every day. The solid line represents the calculated time-weighted average concentration (CAVE), and the dashed line represents the average value of the 7 sampling point concentrations.

[0115] In summary, the present invention provides a convenient, efficient, affordable and durable evaporation-driven sampling device, which innovatively combines the advantages of passive sampling technology, such as low cost, simple structure, convenient operation, no need for power support and long-term personnel monitoring. At the same time, the present invention uses a filter membrane that has no adsorption effect on the target pollutant in the liquid sampler to protect the packing from being affected by microorganisms. Different from the traditional active sampler that requires power support, it not only improves the sampling rate but also avoids the limitations of the disadvantages of traditional technologies. According to different experimental purposes, a liquid sampler can be used to actively capture organic and inorganic analytes in water through the built-in adsorption packing, then the liquid sampler is removed, and the enriched analytes are eluted through devices such as a peristaltic pump.

[0116] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An evaporation-driven water sampling method, characterized in that, Comprising: Using a water sampling device driven by evaporation to sample the water body to be measured. The water sampling device driven by evaporation includes a water inlet end and an evaporation end connected by a water guide pipe. A liquid sampler is provided between the water inlet end and the evaporation end; Placing the water inlet end into the water body to be measured. Driven by the evaporation force at the evaporation end, the water body to be measured is continuously evaporated through the water inlet end, the liquid sampler, and the evaporation end in sequence, so that the substances to be measured in the water body to be measured are continuously collected by the liquid sampler.

2. The water body sampling method based on evaporation drive according to claim 1, wherein The liquid sampler includes an adsorbent filler and a first porous sieve plate and a second porous sieve plate arranged on both sides of the adsorbent filler; Preferably, a first polytetrafluoroethylene filter membrane and a second polytetrafluoroethylene filter membrane are respectively provided on the sides of the first porous sieve plate and the second porous sieve plate away from the adsorbent filler. A limiting ring and a gland are sequentially arranged above the first polytetrafluoroethylene filter membrane.

3. The evaporation-driven water sampling method according to claim 1 or 2, characterized in that The evaporation end includes an evaporation component and a floating component. The evaporation component is fixed on the floating component; the evaporation component includes an evaporation element and a central tube. The central tube is connected to the liquid sampler through the water guide pipe. One end of the evaporation element is connected to the central tube for sucking and evaporating the water in the central tube upward.

4. The water body sampling method based on evaporation drive according to claim 3, characterized in that, The evaporation element is a sponge, a towel or a hydrogel; a large collector is also provided between the central tube and the water guide pipe; Preferably, the evaporation component further includes a top plate arranged above the evaporation element.

5. The water body sampling method based on evaporation driving according to claim 3, wherein The floating component includes a floating plate and a floating block. The floating block is arranged at the bottom of the floating plate. The central tube is fixed on the floating plate; The floating block is made of polyurethane foam, pearl cotton rod, aerogel or wood material.

6. The water body sampling method based on evaporation drive according to claim 1, wherein The water inlet end is provided with a replaceable membrane type needle filter; a glass fiber membrane is arranged in the replaceable membrane type needle filter for intercepting non-dissolved heavy metals.

7. An evaporation-driven water sampling device, characterized in that, Including a water inlet end and an evaporation end connected by a water guide pipe. A liquid sampler is provided between the water inlet end and the evaporation end; the evaporation end includes an evaporation component and a floating component to float on the water surface through the floating component; The evaporation component is fixed on the floating component; the evaporation component includes an evaporation element and a central tube. The central tube is fixed on the floating component, and the lower end is connected to the water guide pipe, and the upper end is connected to the evaporation element; a support rod is provided on the floating component for fixedly arranging a top plate above the floating component. The evaporation element is located between the floating component and the top plate.

8. The water body sampling device based on evaporation drive according to claim 7, characterized in that The liquid sampler includes an adsorbent filler and a first porous sieve plate and a second porous sieve plate arranged on both sides of the adsorbent filler; Preferably, a first polytetrafluoroethylene filter membrane and a second polytetrafluoroethylene filter membrane are respectively provided on the sides of the first porous sieve plate and the second porous sieve plate away from the adsorbent filler. A limiting ring and a gland are sequentially arranged above the first polytetrafluoroethylene filter membrane; The water inlet end is provided with a replaceable membrane type needle filter; a glass fiber membrane is arranged in the replaceable membrane type needle filter for intercepting non-dissolved heavy metals.

9. An evaporation-driven water body detection method, characterized in that, Including the following steps: S1. Using the water sampling method according to any one of claims 1-6 to sample the water body to be measured; S2. After the adoption, remove the liquid sampler. The liquid sampler is rinsed and eluted, and the eluate is collected. Then, test the content of the substance to be measured in the eluate to obtain the content of the substance to be measured in the water body to be measured.

10. The water body detection method based on evaporation drive according to claim 9, wherein The substance to be measured is a heavy metal or an organic substance; when the substance to be measured is a heavy metal, the adsorbent in the liquid sampler uses Chelex 100 sodium-type chelating resin, and when the substance to be measured is an organic substance, the adsorbent uses divinyl / N-vinylpyrrolidone copolymer filler; And / or, before sampling the water body to be measured, first exhaust the air of the water body sampling device driven by evaporation; And / or, the rinsing and elution include: loading the liquid sampler into a filtration adapter, with one end of the filtration adapter connected to a sample bottle and the other end connected to a peristaltic pump; during rinsing, the sample bottle is filled with water, and the peristaltic pump is used to pump water to rinse the substance to be measured adsorbed by the liquid sampler; during elution, the sample bottle is filled with 1wt%-8wt% HNO3, and the peristaltic pump is used to pump nitric acid to elute the substance to be measured adsorbed by the liquid sampler.

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