Evaporation-driven sampling device

Abstract

The utility model belongs to the technical field of water sampling devices, and particularly relates to an evaporation-driven sampling device. Comprising a floating assembly, an evaporation assembly and a liquid sampler, and the evaporation assembly is connected with one end of the liquid sampler through a water guide pipe; the other end of the liquid sampler is connected with a water body to be detected through a water guide pipe; the evaporation assembly is fixed on the floating assembly and floats on the water surface through the floating assembly, and water in a water body to be detected is evaporated upwards through the liquid sampler under the action of the evaporation assembly, so that substances to be detected in the water body to be detected are adsorbed in the liquid sampler. The device is different from a traditional adsorption type sampling device, and overcomes the defect that the traditional adsorption type sampling device needs a large amount of energy to provide sampling power. And meanwhile, a passive sampler is combined as an adsorption device, so that good stability and reutilization effect are achieved.

Description

Technical Field

[0001] This utility model belongs to the technical field of monitoring devices for heavy metal pollution in water, and specifically relates to an evaporation-driven sampling device. Background Technology

[0002] The presence of heavy metal ion pollution and organic pollutants in aquatic environments is concerning because their long-term effects on aquatic organisms and human health are unknown. Sample collection is the first step in environmental analysis, but current active sampling methods suffer from drawbacks such as being time-consuming, labor-intensive, unstable, prone to compositional changes, and requiring complex pretreatment steps. The emergence of some novel battery-powered sampling devices has simplified the sampling process; for example, continuous low concentration level (CLAM) samplers have been applied to monitor pesticides and pesticide degradation products in urban runoff. However, due to the limited energy provided by batteries, the deployment time for active sampling is typically short. Therefore, in recent research, the energy supply for active samplers remains a pressing issue. Utility Model Content

[0003] The purpose of this invention is to provide an evaporation-driven sampling device that utilizes evaporation force to achieve real-time active sampling without consuming electrical energy, thereby improving the sampling rate and avoiding the limitations of traditional technologies.

[0004] To achieve the above objectives, this utility model provides an evaporation-driven sampling device, including a floating component, an evaporation component, and a liquid sampler. The evaporation component is connected to one end of the liquid sampler via a water guide pipe; the other end of the liquid sampler is connected to the water body to be tested via the water guide pipe.

[0005] The evaporation component is fixed to the floating component so that it floats on the water surface through the floating component. The water in the water body to be tested evaporates upward through the liquid sampler under the action of the evaporation component, so as to adsorb the test substances in the water body to be tested into the liquid sampler.

[0006] Furthermore, the liquid sampler includes an adsorbent packing material and a first porous sieve plate and a second porous sieve plate disposed on both sides of the adsorbent packing material.

[0007] Furthermore, a first polytetrafluoroethylene (PTFE) filter membrane and a second PTFE filter membrane are respectively provided on the side of the first porous sieve plate and the second porous sieve plate away from the adsorbent packing. A limiting ring and a pressure cap are sequentially provided above the first PTFE filter membrane.

[0008] Furthermore, the evaporation assembly includes an evaporation element and a central tube. The central tube is fixed to the floating assembly, with its lower end connected to the water guide pipe and its upper end connected to the evaporation element, for drawing water upwards and evaporating it.

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

[0010] Furthermore, the evaporation assembly also includes a top plate disposed above the evaporation element.

[0011] Furthermore, the floating assembly includes a floating plate and a floating block, the floating block being disposed at the bottom of the floating plate, and the central tube being fixed to the floating plate.

[0012] Furthermore, the floating block is made of polyurethane foam, pearl cotton swabs, aerogel, or wood.

[0013] Furthermore, the end of the water pipe connected to the water body to be tested is also equipped with a replaceable membrane needle filter.

[0014] Furthermore, the replaceable membrane needle filter is equipped with a glass fiber membrane for retaining non-dissolved heavy metals.

[0015] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0016] (1) The evaporation-driven sampling device provided by this utility model combines the evaporation component and the liquid sampler to achieve real-time continuous active sampling by utilizing the evaporation force, which not only improves the sampling rate but also overcomes the drawback of traditional adsorption-type sampling devices requiring a large amount of energy to provide sampling power.

[0017] (2) The liquid sampler of this utility model adopts an internal cavity assembly structure to avoid adsorption deviation of target pollutants due to environmental factors, and adopts a hollow cylindrical design to reduce water resistance. After the adsorbent packing is pressed by the porous sieve plate, a layer of polytetrafluoroethylene filter membrane is placed to avoid contamination by impurities in the water body in the field. The microporous structure material of the porous sieve plate can attach a heavy metal film on its surface, and its toxicity prevents the formation of microbial films, thereby avoiding the impact of microbial films on adsorption efficiency.

[0018] (3) This device has a simple structure, low price, and is reusable; it can realize the synchronous monitoring of pollutants at multiple points over a large area, and can realize the synchronous and stable determination of multiple pollutants such as common heavy metal ions and organic matter. It has high measurement capacity and strong environmental resistance. Combined with a liquid sampler, this device has good stability and reusability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the evaporation-driven sampling device of this utility model;

[0020] Figure 2This is a schematic diagram of the evaporation-driven sampling device of this utility model in its operational state.

[0021] Figure 3 This is a schematic diagram of the internal structure of a liquid sampler;

[0022] Figure 4 This is a schematic diagram of the elution device.

[0023] Figure 5 A schematic diagram of the air venting device assembly for a liquid sampler;

[0024] Figure 6 This is a trend graph of evaporation-driven sampling in Example 1, with the number of experimental days as the x-axis and the amount of metal ions sampled in the sampler as the y-axis.

[0025] Figure 7 This is a trend graph of evaporation-driven sampling in Example 2, with evaporation volume as the horizontal axis and the amount of metal ions sampled in the sampler as the vertical axis.

[0026] Figure 8 The results show the concentration test results of different metal ions of this invention over 7 days.

[0027] Explanation of reference numerals in the attached figures:

[0028] 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 pipe; 6-1-First porous sieve plate; 6-2-Second porous sieve plate; 6-3-Limiting ring; 6-4-Capping; 6-5-O-ring; 9-Nose collector; 10-Adapter; 11-Filter adapter; 12-Independent collector; 13-Sample bottle; 14-Hydrophilic sieve plate; 15-Conduction hose; 16-Peristaltic pump; 17-Unsupported PTFE coated bracket; 18-Snap-on. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model. Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0030] Please see Figure 1-3 This utility model provides an evaporation-driven sampling device, 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 tested through the water guide pipe 8.

[0031] The evaporation component is fixed to the floating component so that it floats on the water surface through the floating component. The water in the water body to be tested evaporates upward through the liquid sampler 6 under the action of the evaporation component, so as to adsorb the test substance in the water body to be tested into the liquid sampler 6.

[0032] Specifically, the liquid sampler 6 includes a sleeve and a first porous sieve plate 6-1 and a second porous sieve plate 6-2 placed inside the sleeve from top to bottom. A first polytetrafluoroethylene filter membrane is placed above the first porous sieve plate 6-1, an adsorbent packing 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.

[0033] See Figure 3 The liquid sampler 6 employs an internal cavity assembly structure to avoid adsorption deviations of target pollutants due to environmental factors, and utilizes a hollow cylindrical design to reduce water resistance. In actual use, a 0.45μm polytetrafluoroethylene filter membrane is first placed at the bottom of the sleeve; then a second porous sieve plate 6-2 is placed, followed by the required adsorbent packing material. Different adsorbent packing materials can be selected according to different pollutants. During the experimental stage of the sampling system, analytical grade Chelex 100 sodium chelating resin (200-400 mesh) was used for adsorbing heavy metal ions, and HLB (divinyl / N-vinylpyrrolidone, average particle size 40-60μm) was used as the adsorbent packing material for adsorbing organic pollutants, both achieving excellent adsorption effects. A porous sieve plate, namely the first porous sieve plate 6-1, needs to be added on top of the adsorbent packing to compress the adsorbent packing. Finally, a 0.45μm polytetrafluoroethylene filter membrane needs to be placed. The outermost two filter membranes are used to protect the adsorbent packing and avoid contamination by impurities in the water body. The top is then fixed with a limiting ring 6-3 to ensure that the adsorbent packing is not dispersed by the water flow and to allow the built-in adsorbent packing to stably adsorb the analytes in the environment. Finally, the pressure cap 6-4 is fixed with the matching tool wrench to complete the assembly of the liquid sampler 6.

[0034] Specifically, the porous sieve plate of the liquid sampler 6 uses a microporous material for filtration. Unlike permeable membranes, the microporous material allows heavy metal films to adhere to its surface, preventing the formation of microbial films due to its toxicity, thus avoiding any impact on adsorption efficiency. Two porous sieve plates are placed on the upper and lower sides of the adsorbent packing to support the adsorbent. An additional 0.45μm polytetrafluoroethylene filter membrane is added to the outside of the sieve plates to protect the adsorbent packing. An external retaining ring ensures that the adsorbent remains tightly packed and does not leak out with the water flow.

[0035] The evaporation assembly includes an evaporation element and a central tube 3. The central tube 3 is fixed to the floating assembly, with its lower end connected to the water guide pipe 8 and its upper end connected to the evaporation element, for drawing water upwards and evaporating it. A large collector 4 is also provided between the central tube 3 and the water guide pipe 8. The evaporation element can be a sponge, towel, or hydrogel, etc., and photothermal materials can be composited into such absorbent materials to promote water evaporation through photothermal conversion. The large collector 4 connects the central tube 3 and the water guide pipe 8, allowing water to be stored and evaporated in the central tube 3. The large collector 4 is made of PP material and is funnel-shaped. Its upper central concave part is connected to the central tube 3, and its lower part is pointed. It is connected to the liquid sampler 6 through the water guide tube 8. To prevent the water guide tube 8 from falling off, its pointed part is threaded and fixed with a nut. The nut has a hole in the middle so that the water guide tube 8 can pass through the center. M8 threaded holes are opened around its central concave part. The large collector 4 and the central tube 3 are fixed to the floating plate 2 through the M8 threaded post.

[0036] The evaporation assembly also includes a top plate 1 disposed above the evaporation element, used to fix the evaporation element and prevent rainwater from entering and affecting the evaporation of the evaporation assembly and the sampling results in the liquid sampler 6. The side walls of the evaporation element are all exposed to maximize the evaporation area, allowing water to evaporate from the sides under the influence of wind and other forces at the sampling site.

[0037] 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 swabs, aerogel, or wood, etc. The floating block 5 enables the floating plate 2 to float on the water surface, thereby allowing the evaporation element to float on the water surface.

[0038] The liquid sampler 6 is housed within the nozzle collector 9. The nozzle collector 9 and the replaceable membrane needle filter 7 are equipped with inlets and outlets. The central tube 3 connects to the outlet of the nozzle collector 9 via a water guide pipe 8, and the outlet of the replaceable membrane needle filter 7 connects to the inlet of the nozzle collector 9 via the water guide pipe 8 (e.g., a silicone tube). The inlet of the replaceable membrane needle filter 7 is connected to the external liquid environment. A glass fiber membrane is housed inside the replaceable membrane needle filter 7 and secured with a rubber ring.

[0039] See Figure 5Before loading samples, the assembled liquid sampler 6 needs to be purged of air. In this embodiment, a nozzle collector 9 is nested at the top and bottom of the liquid sampler 6. The outlet of the nozzle collector 9 near the top (cap 6-4 end) of the liquid sampler 6 is connected to a 10mL syringe (needle removed) adapter 10; the outlet of the nozzle collector 9 near the bottom (filter membrane end) of the liquid sampler 6 is placed in pure water. Use the syringe to start drawing pure water. Stop drawing when pure water is drawn into the syringe and remove the syringe. Then take out the liquid sampler 6 nested between the two nozzle collectors 9 and place it in pure water to complete the air purging step.

[0040] In this utility model, the evaporation element is a towel. The towel is fixed between the floating plate 2 and the top plate 1 by several towel clips. The central tube 3 is fixed on the floating plate 2, and one end protrudes from the upper part of the floating plate 2 to connect with the towel. In order 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. Circular magnets are installed in the groove and the towel clip to connect the top plate 1 and the towel clip.

[0041] In this invention, to ensure that the floating plate 2 and the central tube 3 are tightly fitted, a hole is made in the center of the floating plate 2 and waterproof adhesive is applied to ensure that the floating plate 2 and the central tube 3 are tightly fitted.

[0042] In this invention, to ensure a tight fit between the central tube 3 and the large collector 4, a groove is provided at the lower part of the central tube 3, and a large O-ring is installed inside the groove to tightly fit the central tube 3 and the external large collector 4. The lower end of the large collector 4 is threaded.

[0043] In this invention, to ensure that the liquid sampler 6 and the nozzle collector 9 are tightly nested, grooves are provided on the outer sides of both the upper and lower ends of the sleeve, and O-rings 6-5 are installed inside the grooves to tightly fit the sleeve and the outer nozzle collector 9.

[0044] In this utility model, the floating device can be installed in two ways. Assembly method 1: The floating plate 2 is not equipped with the pearl cotton rod 5. In this case, the floating device is connected to the evaporation tank in the following way: The floating plate 2 has fixing holes, and it is fixed to the evaporation tank with screw holes.

[0045] Assembly Method 2: Floating blocks 5, such as pearl cotton swabs or foam, are installed on the floating board 2. In this case, the floating device can be directly placed in outdoor water to achieve floating. Specifically, two floating blocks 5 are installed on the bottom sides of the floating board 2 respectively. Through the buoyancy of the floating blocks 5, all components above the floating board 2 are above the water surface.

[0046] After being placed in the target water body, this evaporation-driven sampling device, due to atmospheric pressure, first filters the water sample through a polytetrafluoroethylene (PTFE) membrane and then enters the liquid sampler 6 containing Chelex 100 resin (adsorbent packing). Finally, the sample rises to the central tube 3 until it is level with the outside water surface. The water on the towel evaporates naturally and continuously draws water from the central tube 3, thus enabling the evaporation-driven sampler to continuously collect water samples. Dissolved heavy metals in the water sample are fixed on the Chelex 100 resin packing during this process, while undissolved heavy metals are retained by the glass fiber membrane in the replaceable membrane needle filter 7.

[0047] Please see Figure 4 The top of the filter adapter 11 is connected to the sample bottle 13, and the two are connected by a snap-fit ​​18. A hydrophilic sieve plate 14 is installed between the filter adapter 11 and the sample bottle 13 to pre-filter the incoming water (a 0.2μm microporous aqueous filter membrane can be covered to prevent the hydrophilic sieve plate from floating). The liquid sampler 6 is connected to the inside of the filter adapter 11 and nested in the independent collector 12 at the bottom. The outlet of the independent collector 12 is connected to a conductive hose 15 with an inner diameter of 3mm and a wall thickness of 1mm, which elutes the sample into the collection container through a peristaltic pump 16. This device is used for the elution process.

[0048] 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 is suitable for various water environments.

[0049] The present invention will be further described in detail below with reference to specific embodiments:

[0050] Sampler field performance and initial applications:

[0051] The evaporation-driven sampler of this invention was deployed in field water bodies and simulated water bodies to collect heavy metals and organic pollutants to evaluate its performance in real-world environments.

[0052] The sampling process of the liquid sampling system can be selected according to the target pollutant to be measured.

[0053] Heavy metals: Activation - Air removal - Active sampling - Membrane removal - Washing - Elution - Analysis.

[0054] Example 1

[0055] Example of active sampling for heavy metals (Nanhu Lake water);

[0056] This embodiment provides an example of active sampling and analysis of common divalent metal ions in water bodies, which can effectively characterize the risk of water pollutants.

[0057] 1.1 Sampling

[0058] Use a 1L plexiglass sampler to continuously collect 5L of water from Nanhu Lake. During the collection process, be careful to avoid using metal objects.

[0059] 1.2 Sampler for recovering heavy metals from water bodies

[0060] Instruments and consumables: BT100-L peristaltic pump, pump head DG-6 or DG-12 (6-channel or 12-channel), 3*1 (3mm inner diameter, 1mm wall thickness) or 16# (3.2mm inner diameter, 1.6mm wall thickness) hose, and plexiglass container.

[0061] Chelex 100 sodium chelating resin (200-400 mesh) adsorbent packing material was used to recover divalent metal ions from water.

[0062] Perform the following steps in sequence:

[0063] (1) Assemble the liquid sampler: Place the second porous sieve plate (5μm pore size, PP material), 0.5g Chelex100 sodium chelating resin, the first porous sieve plate (5μm pore size, PP material), the 0.45μm polytetrafluoroethylene membrane, and the limiting ring into the sleeve in sequence, and finally use a wrench to cover the pressure cap.

[0064] (2) Activation: Based on the number of peristaltic pump channels, a corresponding number of active and passive sampling devices can be set to carry out multi-channel sample enrichment and recovery. In this embodiment, 6 sets of experiments are set (5 parallel experimental groups and 1 blank experimental group respectively). 10 mL of 0.5 mol / L sodium acetate is added to each of the 6 sample bottles 13. To prevent filter membrane damage, the flow rate of the peristaltic pump is set to 1.5 mL / min. After turning on, the pump is dried to activate the Chelex 100 sodium chelating resin.

[0065] (3) Air removal: Nest the assembled liquid sampler 6 inside the two nozzle collectors 9. Install the syringe adapter 10 at the outlet of the nozzle collector on the cap. Put the outlet of the nozzle 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 nozzle collectors 9 at both ends in sequence. Then immerse the liquid sampler in pure water for later use.

[0066] (4) According to Figure 1 and 2 The evaporation-driven sampling device is assembled. In this embodiment, the parts are connected by a 3.2*1.6 (inner diameter 3.2mm, wall thickness 1.6mm) connection.

[0067] (5) After assembling the evaporation-driven sampling device, leave it overnight and observe whether the water level in the central tube is level with the water level in the plexiglass container. Once the water levels are level, the device can be placed in a suitable location. Figure 2 As shown.

[0068] (6) Membrane removal: After the experimental cycle is completed, retrieve the device and remove the liquid sampler 6. Use a wrench and tweezers to help remove the polytetrafluoroethylene filter membranes at both ends of the liquid sampler 6, and then put the liquid sampler 6 back into the filter adapter 11. After removing the replaceable membrane needle filter 7, use tweezers to help put the glass fiber membrane inside the replaceable membrane needle filter 7 into a 50mL centrifuge tube and add 20mL of 5wt% HNO3 (for subsequent sample analysis).

[0069] (7) Rinsing: 10 mL of pure water was added to filter adapter 11 for all 6 test groups. The peristaltic pump was set to a flow rate of 1 mL / min and then drained. The liquid extracted in the above steps was treated as waste liquid.

[0070] (8) Elution: 10 mL of 5 wt% HNO3 was added to filter adapter 11 for all 6 experimental groups. The peristaltic pump flow rate was set to 1 mL / min. After turning it on, the pump was dried to complete the elution. The eluent was collected in a 15 mL centrifuge tube.

[0071] 1.3 Sample Analysis

[0072] By using ICP-OES to analyze the content of heavy metals in the eluent, the concentration of heavy metals in the water can be calculated based on the concentration factor.

[0073] 1.4 Results Analysis

[0074] The contents of four metal ions (cadmium, lead, chromium, and copper) in the eluent 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. Based on the concentration factor (sample volume 500 mL / eluent volume 10 mL) of this active sampling experiment (50), the heavy metal content in the sampled Nanhu water can be calculated according to the formula: heavy metal content = detected value / concentration factor (Table T1). Further analysis and research can then be carried out (it has been verified in this invention that the above elution process can ensure complete elution of heavy metals).

[0075] Table 1. Statistical characteristics of heavy metal content in Nanhu Lake (unit: μg·L) -1 )

[0076]

[0077] from Figure 6 It can be seen that as the number of sampling days increases, the amount of adsorbed heavy metals gradually increases, indicating that the evaporation-driven sampling device can drive the water to flow upwards and allow the heavy metals to be adsorbed by the liquid sampler 6.

[0078] Example 2

[0079] Example of active sampling for heavy metals (spikeped tap water).

[0080] This embodiment provides an example of active sampling and analysis of trace divalent metal ions in water, which can effectively characterize the risk of water pollutants.

[0081] The active sampling of heavy metals was carried out in accordance with the method of Example 1 above. The difference is that the water sample used in Example 1 was a water sample from Nanhu Lake, while the water sample used in Example 2 was spiked tap water. The steps are the same as those in 1.3-1.4 of Example 1.

[0082] 2.1 Sampler for recovering heavy metals from water bodies

[0083] Instruments and consumables: BT100-L peristaltic pump, DG-6 or DG-12 pump head (6-channel or 12-channel), 3*1 (3mm inner diameter, 1mm wall thickness) or 16# (3.2mm inner diameter, 1.6mm wall thickness) hose, plexiglass container, and mixing standard.

[0084] Chelex 100 sodium chelating resin (200-400 mesh) adsorbent packing material was used to recover divalent metal ions from water.

[0085] Perform the following steps in sequence:

[0086] (1) Assemble the liquid sampler: Place the following components in sequence inside the sleeve: 0.45μm polytetrafluoroethylene filter membrane, second porous sieve plate (5μm pore size, PP material), 0.5g Chelex100 sodium chelating resin, first porous sieve plate (5μm pore size, PP material), 0.45μm polytetrafluoroethylene filter membrane, and limiting ring. Finally, use a wrench to cover the pressure cap.

[0087] (2) Air removal: Nest the assembled liquid sampler inside the two nozzle collectors. Install the syringe adapter at the outlet of the nozzle collector with the cap. Put the outlet of the nozzle 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 nozzle collectors at both ends in sequence. Then immerse the liquid sampler in pure water for later use.

[0088] (3) Activation: Based on the number of peristaltic pump channels, a corresponding number of active and passive sampling devices can be set to carry out multi-channel sample enrichment and recovery. In this embodiment, 6 sets of experiments are set (5 parallel experimental groups and 1 blank experimental group respectively). 10 mL of 0.5 mol / L CH3COONH4 is added to each of the 6 sample bottles 5. To prevent filter membrane damage, the flow rate of the peristaltic pump is set to 1.5 mL / min. After turning on, the pump is dried for activation.

[0089] (4) Assemble the evaporation-driven sampling device according to the figure. In this embodiment, the parts are connected by 3*1 (inner diameter 3mm, wall thickness 1mm) or 16# (inner diameter 3.2mm, wall thickness 1.6mm) flexible tubing.

[0090] (5) After the device is assembled, leave it overnight and observe whether the water level in the central tube is level with the water level in the plexiglass bucket. Once the water levels are level, the device can be placed in a suitable location.

[0091] (6) Membrane removal: After the experimental cycle is completed, retrieve the device and remove the liquid sampler 6. Use a wrench and tweezers to help remove the polytetrafluoroethylene filter membranes at both ends of the liquid sampler and then put the liquid sampler back in. After removing the replaceable membrane needle filter, use tweezers to help put the glass fiber membrane inside the replaceable membrane needle filter 9 into a 50mL centrifuge tube and add 20mL of 5wt% HNO3.

[0092] (7) Rinsing: 10 mL of pure water was added to the filter adapter for each of the 6 experimental groups. The peristaltic pump was set to a flow rate of 1 mL / min and then drained. The liquid extracted in the above steps was treated as waste liquid.

[0093] (8) Elution: 10 mL of 5 wt% HNO3 was added to the filter adapter for each of the 6 experimental groups. The peristaltic pump was set to a flow rate of 1 mL / min. After turning it on, the pump was dried to complete the elution. The eluent was collected in a 15 mL centrifuge tube.

[0094] 2.2 Sample Analysis

[0095] By using ICP-OES to analyze the content of heavy metals in the eluent, the concentration of heavy metals in the water can be calculated based on the concentration factor.

[0096] 2.3 Results Analysis

[0097] The contents of four metal ions (cadmium, lead, manganese, and nickel) in the eluent 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. Based on the concentration factor (sample volume 500 mL / eluent volume 10 mL) of this active sampling experiment (50), the heavy metal content in the sampled Nanhu water can be calculated according to the formula: heavy metal content = detected value / concentration factor (Table T1), and further analysis and research can be carried out. (It has been verified in this utility model that the above elution process can ensure complete elution of heavy metals.)

[0098] Table 2 Statistical characteristics of heavy metal content in Nanhu Lake (unit: μg·L) -1 )

[0099] 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

[0100] from Figure 7It can be seen that as the evaporation volume increases, the amount of metal ions sampled in the sampler gradually increases.

[0101] The concentration of the target heavy metal was determined by collecting and measuring simulated contaminated water samples indoors for 7 days (the simulated contaminated water was prepared by adding tap water to a 100 mg / L heavy metal standard solution; the theoretical concentration of the simulated heavy metal was 20 μg / L, including both free and precipitated components). Figure 8 The dots represent the concentration in water samples collected simultaneously each day. The solid line represents the calculated time-weighted average concentration (CAVE), and the dashed line represents the average concentration of the seven samples.

[0102] In summary, this invention provides a convenient, efficient, affordable, and durable evaporation-driven sampling device. It innovatively combines the advantages of passive sampling technology, such as low cost, simple structure, easy operation, and no need for power support or long-term personnel monitoring. Furthermore, this invention utilizes a unique liquid sampler with a filter membrane that does not adsorb the target pollutants, protecting the packing material from microbial influence. Unlike traditional active samplers that require power, this invention improves the sampling rate while avoiding the limitations of traditional technologies. Depending on the experimental purpose, the liquid sampler can be used to actively capture organic and inorganic analytes in water via the built-in adsorption packing material. After removing the liquid sampler, the concentrated analytes are eluted using a peristaltic pump or similar device.

[0103] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An evaporation-driven sampling device, characterized in that, It includes a floating assembly, an evaporation assembly, and a liquid sampler (6). The evaporation assembly is connected to one end of the liquid sampler (6) via a water pipe (8). The other end of the liquid sampler (6) is connected to the water body to be tested via the water pipe (8). The evaporation component is fixed to the floating component.

2. The evaporation-driven sampling device according to claim 1, characterized in that, The liquid sampler (6) includes an adsorbent packing and a first porous sieve plate (6-1) and a second porous sieve plate (6-2) disposed on both sides of the adsorbent packing.

3. The evaporation-driven sampling device according to claim 2, characterized in that, The first porous sieve plate (6-1) and the second porous sieve plate (6-2) are respectively provided with a first polytetrafluoroethylene filter membrane and a second polytetrafluoroethylene filter membrane on the side away from the adsorbent packing. A limiting ring (6-3) and a pressure cap (6-4) are sequentially provided above the first polytetrafluoroethylene filter membrane.

4. The evaporation-driven sampling device according to claim 1, characterized in that, The evaporation assembly includes an evaporation element and a central tube (3). The central tube (3) is fixed to the floating assembly and its lower end is connected to the water guide pipe (8), while its upper end is connected to the evaporation element.

5. The evaporation-driven sampling device according to claim 4, characterized in that, The evaporation element is a sponge, towel or hydrogel; a large collector (4) is also provided between the central tube (3) and the water guide tube (8).

6. The evaporation-driven sampling device according to claim 4, characterized in that, The evaporation assembly also includes a top plate (1) disposed above the evaporation element.

7. The evaporation-driven sampling device according to any one of claims 4-6, characterized in that, The floating assembly includes a floating plate (2) and a floating block (5), the floating block (5) being disposed at the bottom of the floating plate (2), and the central tube (3) being fixed to the floating plate (2).

8. The evaporation-driven sampling device according to claim 7, characterized in that, The floating block (5) is made of polyurethane foam, pearl cotton swabs, aerogel or wood.

9. The evaporation-driven sampling device according to claim 1, characterized in that, The end of the water pipe (8) connected to the water body to be tested is also equipped with a replaceable membrane needle filter (7).

10. The evaporation-driven sampling device according to claim 9, characterized in that, The replaceable membrane needle filter (7) is equipped with a glass fiber membrane.

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