Nanofiltration osmotic pump sampler

Abstract

The utility model relates to the technical field of water body samplers, in particular to a nanofiltration osmotic pump sampler which comprises an osmotic pump, the osmotic pump comprises a water inlet cavity, a water outlet cavity and an osmotic membrane, the water inlet cavity is filled with deionized water, anion exchange resin and cation exchange resin, and the water outlet cavity is filled with saturated draw liquid and solid draw substances. The solid absorbing substance is used for maintaining the concentration of the penetrating fluid after being dissolved, so that osmotic pressure is formed on the two sides of the osmotic membrane, water molecules enter the water outlet cavity from the water inlet cavity through the osmotic membrane, and the osmotic membrane is a nanofiltration membrane with the pore diameter being more than 1 nanometer; and substances formed after the solid-state absorbing substances are decomposed are bivalent and above high-valence ions or the outer diameter of the substances is greater than the aperture of the nanofiltration membrane. Water flow velocity on two sides of the osmotic membrane is increased by increasing the aperture of the osmotic membrane, so that water sampling speed is increased, types of drawn liquid are correspondingly changed, pressure difference on two sides of the osmotic membrane is maintained, and flow velocity of the osmotic pump is maintained.

Description

Technical Field

[0001] The utility model relates to the technical field of water samplers, in particular to a nanofiltration osmotic pump sampler. Background Art

[0002] Existing osmotic pump type samplers use osmotic pressure to provide power, see Figure 1 As shown, the core component of the sampler is an osmotic pump 100, which is divided into two parts, an upper part and an lower part, with a reverse osmosis membrane 101 in the middle (allowing water to pass through and blocking the passage of separators), a saturated sodium chloride solution and solid sodium chloride are provided on the upper layer, and deionized water and anion and cation exchange resins are provided on the lower layer. After the sampler is constructed, due to the osmotic pressure generated by the solution difference on both sides of the reverse osmosis membrane 101, the water flux of deionized water entering the saturated sodium chloride solution from bottom to top is greater than the reverse flow, so that more water enters the saturated sodium chloride solution per unit time, thereby providing driving force for the entire sampler, collecting water samples from the outside, and the target substances in the collected water samples are enriched on the solid phase extraction column 200, and the remaining samples are stored in the water storage coil 300.

[0003] However, the existing osmotic pump sampler mainly focuses on substances with a concentration of about milligrams per liter, such as nitrate, phosphate, chloride and metal ions in the surface water environment. According to the existing instrument detection technology, 20 ml is collected every day to analyze the time-weighted average concentration of the day. Therefore, the sampling flow rate per unit time of the sampler is low, and only 0.83 ml / h is required. When the sampler is used for monitoring trace substances such as new pollutants, since the maximum pore size of the reverse osmosis membrane 101 is only about 0.1 nanometers, the flow rate is slow. In order to collect enough detection volume (500 ml), it takes about 6 days (that is, only about 85 ml can be collected every day), and in actual operation, it is generally laid continuously for 10 days. Therefore, the existing osmotic pump sampler has a small driving force, a slow flow rate, and a long collection time, which is not conducive to the detection of trace substances and microbial sample collection. Summary of the invention

[0004] The utility model aims to solve the problems of low driving force, slow flow rate and long collection time of existing osmotic pump samplers, and to provide a nanofiltration osmotic pump sampler with high driving force, fast flow rate and suitable for detecting trace substances and collecting microbial samples.

[0005] To achieve the above-mentioned purpose, the technical solution of the utility model is: a nanofiltration osmotic pump sampler, including an osmotic pump, the osmotic pump including an inlet chamber, an outlet chamber and an osmotic membrane arranged between the inlet chamber and the outlet chamber, the inlet chamber is filled with deionized water and anion and cation exchange resins, the outlet chamber is filled with saturated draw liquid and solid draw substances, the solid draw substances are used to maintain the concentration of the draw liquid after dissolution, so that osmotic pressure is formed on both sides of the osmotic membrane to allow water molecules to enter the outlet chamber from the inlet chamber through the osmotic membrane, the osmotic membrane is a nanofiltration membrane with a pore size of more than 1 nanometer, and the substances formed after the decomposition of the osmotic liquid are high-valent ions greater than or equal to divalent or their outer diameters are greater than the pore size of the nanofiltration membrane.

[0006] Furthermore, the permeable membrane is a nanofiltration membrane with a pore size of 1 nanometer to 2 nanometers.

[0007] Furthermore, the drawn liquid is a magnesium sulfate solution, and the solid drawn substance is a magnesium sulfate solid.

[0008] Furthermore, it also includes a coil connected to the water inlet chamber, which is a rubber tube filled with deionized water and is used to connect to the sampled water area, so that the deionized water in the coil enters the water inlet chamber under the action of the osmotic pump, and the water in the sampled water area is stored in the coil.

[0009] Furthermore, the inner diameter of the rubber tube is 4 mm, and the volume of the rubber tube is 1 L.

[0010] Furthermore, it also includes a multi-stage filtration system connected to the coil, which includes at least a first filter and a second filter arranged in sequence along the flow direction of the water body in the sampler, and the pore size of the first filter is larger than the pore size of the second filter to grade and filter substances in the water body.

[0011] Furthermore, the multi-stage filtration system is a three-stage filtration system, which also includes a third filter connected to the second filter, and the first filter, the second filter and the third filter are arranged in sequence along the flow direction of the water body in the sampler, and the pore sizes of the first filter, the second filter and the third filter decrease in sequence.

[0012] Furthermore, the pore sizes of the first filter, the second filter and the third filter are 1.0 to 1.5 microns, 0.35 to 0.55 microns and 0.18 to 0.25 microns respectively.

[0013] Furthermore, a coil is provided between the water inlet chamber and the multi-stage filtration system, so that the multi-stage filtration system is indirectly connected to the water inlet chamber through the coil, and the coil is a rubber tube filled with deionized water.

[0014] The utility model has the following beneficial effects: the water flow rate on both sides of the osmotic membrane is increased by increasing the pore size of the osmotic membrane, thereby increasing the sampling speed of the environmental water body; and the ions formed after the solid absorption material is decomposed are replaced by the osmotic liquid of divalent ions, thereby increasing the outer diameter of the ions, thereby preventing the ions from passing through the osmotic membrane into the water inlet chamber and reducing the osmotic pressure difference on both sides of the osmotic membrane, thereby maintaining the flow rate of the osmotic pump; the solid magnesium sulfate has good water solubility, and can be dissolved in water when deionized water enters the water outlet chamber to reduce the concentration of the magnesium sulfate solution, thereby maintaining the concentration of the magnesium sulfate solution, and further maintaining the flow rate of the osmotic pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an existing sampler.

[0016] Figure 2 It is a structural schematic diagram of embodiment 1 of the utility model.

[0017] Figure 3 It is a schematic diagram of the structure of the osmotic pump of Example 1 of the utility model.

[0018] Figure 4 It is a structural schematic diagram of embodiment 2 of the present utility model.

[0019] Figure 5 It is a structural schematic diagram of embodiment 3 of the present utility model.

[0020] Wherein: 1 osmotic pump, 11 water inlet chamber, 12 water outlet chamber, 13 osmotic membrane, 2 coils, 3 three-stage filtration system, 31 first filter, 32 second filter, 33 third filter, 4 metering bag. DETAILED DESCRIPTION

[0021] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0022] Example 1

[0023] See also Figure 2 and Figure 3As shown, the utility model discloses a nanofiltration osmotic pump sampler, comprising an osmotic pump 1, a coil 2 and a three-stage filtration system 3, the osmotic pump 1 comprising an inlet chamber 11, an outlet chamber 12 and an osmotic membrane 13 arranged between the inlet chamber 11 and the outlet chamber 12, the inlet chamber 11 is filled with deionized water and anion and cation exchange resins, the outlet chamber 12 is filled with saturated osmotic liquid and solid osmotic substances, the solid osmotic substances are used to maintain the concentration of the osmotic liquid after dissolution, so that osmotic pressure is formed on both sides of the osmotic membrane 13 so that water molecules enter the outlet chamber 12 from the inlet chamber 11 through the osmotic membrane 13. The outlet chamber 12 is connected to a metering bag 4, which can be used to measure the volume of the sample.

[0024] The osmotic membrane 13 is a nanofiltration membrane with a pore size of more than 1 nanometer, preferably a nanofiltration membrane between 1 nanometer and 2 nanometers. A nanofiltration membrane with a larger pore size is used instead of a reverse osmosis membrane with a smaller pore size. By increasing the pore size of the osmotic membrane 13, the water flow rate on both sides of the osmotic membrane 13 is increased, thereby increasing the sampling speed of the water body.

[0025] There are two factors that affect the interception of substances by nanofiltration membranes: charge effect and screening effect. The more charge and the larger the volume of the intercepted substances, the better the interception effect. After the utility model adopts nanofiltration membrane as the permeable membrane 13, the sodium ions and chloride ions in the sodium chloride solution are monovalent ions with less charge, which are less affected by the charge effect of the nanofiltration membrane and are not easily intercepted. In addition, the outer diameter of the ions is small, and it is easy to pass through the permeable membrane and enter the water inlet chamber 11, which will reduce the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12, thereby affecting the sampling flow rate and stability.

[0026] In order to avoid this problem, the charge or outer diameter of the substance formed after the decomposition of the solid-state extraction substance is increased accordingly while increasing the pore size of the permeable membrane, so as to prevent the free-state extraction substance formed after the solid-state extraction substance is dissolved from passing through the permeable membrane 13 and entering the water inlet chamber 11, thereby maintaining the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12 within a certain range, and ensuring the stability of the sampling speed. The substance formed after the solid-state extraction substance is dissolved can be selected as a high-valent ion greater than or equal to divalent or its outer diameter is greater than the pore size of the nanofiltration membrane. The charge effect of high-valent ions is more obvious. Even if its outer diameter is smaller than the minimum pore size of the nanofiltration membrane, it is not easy to pass through the nanofiltration membrane under the action of the charge effect, including divalent ions, trivalent ions or higher valent ions; and for uncharged substances, they are not affected by the charge effect, and rely on the screening effect to prevent them from passing through the nanofiltration membrane. Its pore size should be greater than the minimum pore size of the nanofiltration membrane. Sugar substances are uncharged and the free-state substances formed after they are dissolved are larger and are not easy to pass through the nanofiltration membrane. In this example, the extraction liquid is further preferably a magnesium sulfate solution, and accordingly, the solid-state extraction substance is a magnesium sulfate solid. Since the interception rate of the nanofiltration membrane for divalent ions and higher ions is relatively high, generally 90% or more, and the magnesium sulfate solution is highly water-soluble, the magnesium sulfate solution is used as the draw liquid, which can well ensure the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12. In other embodiments, the solid draw material forming the permeate can be one or more of aluminum sulfate, ferric sulfate, ferrous sulfate, and sugars. After the sugar molecules are dissolved in water, they are relatively large and are not easy to pass through the permeable membrane 13 due to the screening effect.

[0027] Without changing the size of the osmotic pump 1, the sampling speeds of the two osmotic pumps are calculated by only changing the osmotic membrane 13 and the type of the drawn liquid. Taking a square osmotic membrane with a side length of 9.5 cm as an example, in an environment with an ambient temperature of 30 degrees Celsius, when a traditional reverse osmosis membrane is used, the sampling water volume per day is about 85 ml. When the nanofiltration membrane with a pore size between 1 nanometer and 2 nanometers described in the utility model is used, the sampling water volume per day can reach more than 700 ml. Therefore, when the sampler is used for monitoring trace substances such as new pollutants, it only takes one day to collect a sufficient detection volume (500 ml).

[0028] The pore size selection of the nanofiltration membrane is related to the size of the ions or molecules after the solid absorbent is dissolved. Nanofiltration membranes with different pore sizes are selected according to different solid absorbents. When selecting, it should be noted that the outer diameter of the solid absorbent after dissolution should be close to or larger than the pore size of the nanofiltration membrane.

[0029] See also Figure 2As shown, the collected water sample is stored in the coil 2, which is a rubber tube. Before collection, the coil 2 is filled with deionized water. One end of the coil is connected to the water inlet chamber 11, and the other end is connected to the sampled water area. When the deionized water in the water inlet chamber enters the water outlet chamber 12 under the action of osmotic pressure, the water pressure in the water inlet chamber 11 decreases, and the deionized water in the coil 2 enters the water inlet chamber 11 under the action of water pressure, and the water in the sampled water area is stored in the coil, thereby completing the sampling.

[0030] In order to collect enough water samples, the volume of the rubber tube should be larger than the required detection volume. In this example, a rubber tube with an inner diameter of 4 mm and a length of about 80 m is used, and the volume of the rubber tube is 1 L.

[0031] If there is no coil 2, and the sampled water area contains more impurities (minerals decomposed into ions, microorganisms, etc.), the water in the sampled water area directly entering the water inlet chamber 11 will increase the liquid concentration of the water inlet chamber 11, thereby reducing the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12, affecting the sampling speed. Therefore, the coil 2 is set to maintain the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12, thereby maintaining the sampling speed.

[0032] See also Figure 2 As shown, the three-stage filtration system 3 is connected to the coil 2, which includes a first filter 31, a second filter 33 and a third filter 33 arranged in sequence along the flow direction of the water body in the sampler, and the apertures of the first filter 31, the second filter 32 and the third filter 33 are reduced in sequence to filter the microbial community in the water sample in three stages, so as to prepare for the detection of the microbial community remaining in each filter after the sampling is completed. The aperture of the first filter is 1.0 to 1.5 microns, preferably 1.2 microns in this example, which is used to filter most insoluble particles in the water body; the aperture of the second filter is 0.35 to 0.55 microns, preferably 0.45 microns in this example, which is used to filter most bacterial microorganisms in the water body; the aperture of the third filter is 0.18 to 0.25 microns, preferably 0.22 microns in this example, which is used to further filter bacterial microorganisms in the water body.

[0033] In other embodiments, a two-stage or more than three-stage multi-stage filtration system can be used to replace the three-stage filtration system. When the multi-stage filtration system is a two-stage filtration system, it only includes the first filter 31 and the second filter 32. When the multi-stage filtration system is more than three stages, the number of filters can be increased accordingly. The pore size of each filter is changed accordingly according to the substance to be filtered, and the pore size is not limited to the above-mentioned size (1.2 microns, 0.45 microns, 0.22 microns).

[0034] See also Figure 2 and Figure 3As shown, the workflow of the utility model is as follows: before sampling begins, the water inlet chamber 11 of the osmotic pump 1 and the coil 2 are filled with deionized water (with the largest chemical potential), and anion and cation exchange resins are added to the water inlet chamber 11 of the osmotic pump to remove sulfate ions and magnesium ions that reversely permeate the nanofiltration membrane; the water outlet chamber 21 is filled with a saturated magnesium sulfate solution (with a small chemical potential), and magnesium sulfate solid (with good water solubility) is added to prevent the solution concentration from decreasing. On both sides of the nanofiltration membrane, due to the osmotic pressure generated by the solution concentration difference, water molecules will pass through the nanofiltration membrane from the side with a high chemical potential to the side with a low chemical potential (i.e., from the water inlet chamber 11 to the water outlet chamber 12). After the water molecules enter the side of the water outlet chamber 122, the concentration of the saturated magnesium sulfate solution will decrease. At this time, since the magnesium sulfate solid added in advance will dissolve, the solution concentration remains unchanged, so that the solution concentration difference between the two sides remains unchanged (i.e., the osmotic pressure remains unchanged), thereby providing a stable and continuous driving force for the sampler. After the deionized water in the water inlet chamber 11 enters the water outlet chamber 12, the water pressure in the water inlet chamber 11 decreases, and the deionized water in the coil 2 enters the water inlet chamber 11. The water in the sampled water area passes through the tertiary filtration system 3 and enters the coil 2 under the action of the pressure difference, and is thus stored in the coil 2. The microbial community trapped in the tertiary filtration system 3 can be used for related detection and analysis.

[0035] Example 2

[0036] See also Figure 4 As shown, the difference between this embodiment and embodiment 1 is that this embodiment does not have a three-stage filtration system 3, and the water inlet end of the coil 2 directly extends into the sampled water area. When it is not necessary to conduct a separate detection and analysis of the microbial community in the water body but to conduct a comprehensive analysis of the water quality of the sampled water area, the collected water sample is stored in the coil 2 for subsequent detection and analysis of the water sample. In order to improve the accuracy of the detection, bubbles should be injected into the coil 2 to separate the deionized water pre-stored in the coil 2 from the collected water sample, and the metering bag 4 can be used as an auxiliary metering tool.

[0037] Example 3

[0038] See also Figure 5As shown, the difference between this embodiment and embodiment 1 is that the coil 2 is not provided in this embodiment, and the three-stage filtration system 3 is directly connected to the water inlet chamber 11 of the osmotic pump 1. The sampler of this embodiment is suitable for the case where the water quality of the sampled water area is relatively pure. At this time, the sampled water contains only a small amount of impurities or ions. Therefore, when the sampled water enters the water inlet chamber 11, the anion and cation exchange resins in the water inlet chamber 11 can remove the small amount of ions contained in the water, maintain the osmotic pressure difference between the water inlet chamber 11 and the water outlet chamber 12, and ensure the sampling speed. According to the description of embodiment 1, the coil 2 is relatively long (80m) and has an inner diameter of 4mm. Therefore, the coil 2 occupies a large volume in the entire sampler. The removal of the coil 2 in this embodiment can greatly reduce the volume of the sampler (reduced by about 2 / 3) and improve the convenience of sampling.

[0039] Both this embodiment and embodiment 1 collect microbial communities in the water area through the three-stage filtration system 3. The difference is that the water quality of the sampled water area is different. When the water quality of the sampled water area is relatively pure, the anion and cation exchange resins in the water inlet chamber 11 can maintain the osmotic pressure difference on both sides of the permeable membrane 13. Therefore, the sampler can use the structure of this embodiment; when the water quality of the sampled water area is relatively complex and contains more impurities, the anion and cation exchange resins cannot handle a large amount of anions and cations, which will cause the osmotic pressure difference on both sides of the permeable membrane 13 to decrease. Therefore, the sampler adopts the structure of embodiment 1.

[0040] Although the present invention is specifically demonstrated and described in conjunction with the preferred embodiments, those skilled in the art should understand that the remaining undescribed portions are prior art, and that various changes made to the present invention in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims shall fall within the scope of protection of the present invention.

Claims

1. A nanofiltration osmotic pump sampler, comprising an osmotic pump, characterized in that: The osmotic pump comprises an inlet chamber, an outlet chamber and an osmotic membrane arranged between the inlet chamber and the outlet chamber, wherein the inlet chamber is filled with deionized water and anion and cation exchange resins, and the outlet chamber is filled with saturated extraction liquid and solid extraction substances, wherein the solid extraction substances are used to maintain the concentration of the osmotic liquid after being dissolved, thereby forming osmotic pressure on both sides of the osmotic membrane to allow water molecules to enter the outlet chamber from the inlet chamber through the osmotic membrane, wherein the osmotic membrane is a nanofiltration membrane with a pore size of more than 1 nanometer, and the substances formed after the decomposition of the solid extraction substances are high-valent ions greater than or equal to divalent ions or whose outer diameter is greater than the minimum pore size of the nanofiltration membrane.

2. A nanofiltration osmotic pump sampler according to claim 1, characterized in that: The permeable membrane is a nanofiltration membrane with a pore size of 1 nanometer to 2 nanometers.

3. A nanofiltration osmotic pump sampler according to claim 1 or 2, characterized in that: The drawn liquid is a magnesium sulfate solution, and the solid drawn substance is a magnesium sulfate solid.

4. The nanofiltration osmotic pump sampler according to claim 1, characterized in that: It also includes a coil connected to the water inlet chamber, which is a rubber tube filled with deionized water and is used to connect to the sampled water area, so that the deionized water in the coil enters the water inlet chamber under the action of the osmotic pump, and the water in the sampled water area is stored in the coil.

5. A nanofiltration osmotic pump sampler according to claim 4, characterized in that: The inner diameter of the rubber tube is 4 mm, and the volume of the rubber tube is 1 L.

6. The nanofiltration osmotic pump sampler according to claim 1, characterized in that: It also includes a multi-stage filtration system connected to the water inlet chamber, which includes at least a first filter and a second filter arranged in sequence along the flow direction of the water body in the sampler, and the pore size of the first filter is larger than the pore size of the second filter to grade and filter substances in the water body.

7. A nanofiltration osmotic pump sampler according to claim 6, characterized in that: The multi-stage filtration system is a three-stage filtration system, and also includes a third filter connected to the second filter. The first filter, the second filter and the third filter are arranged in sequence along the flow direction of the water body in the sampler, and the pore sizes of the first filter, the second filter and the third filter decrease in sequence.

8. The nanofiltration osmotic pump sampler according to claim 7, characterized in that: The pore sizes of the first filter, the second filter and the third filter are 1.0 to 1.5 microns, 0.35 to 0.55 microns and 0.18 to 0.25 microns respectively.

9. The nanofiltration osmotic pump sampler according to claim 6, characterized in that: A coil is also provided between the water inlet chamber and the multi-stage filtering system, so that the multi-stage filtering system is indirectly connected to the water inlet chamber through the coil, and the coil is a rubber tube filled with deionized water.

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