CN110988103A

CN110988103A - Microporous gradient diffusion film device and application thereof

Info

Publication number: CN110988103A
Application number: CN201911280900.5A
Authority: CN
Inventors: 荣楠; 王一舒; 廖文; 吴烨; 吴孝情; 周道坤
Original assignee: South China Institute of Environmental Science of Ministry of Ecology and Environment
Current assignee: South China Institute of Environmental Science of Ministry of Ecology and Environment
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-04-10

Abstract

The invention discloses a micropore gradient diffusion film device and application thereof, and particularly relates to the technical field of environmental science. According to the invention, the driving ring is rotated to drive the threaded sleeve to rotate, so that the inner wall of the threaded sleeve is meshed with the surface of the cap, the cap can be driven by the threaded sleeve to move up and down, the cap drives the pressing ring to move up and down, the thickness of a space for placing the DGT membrane assembly is changed, and the DGT membrane assembly is tightly attached to the top of the bearing seat when the pressing ring moves downwards, so that the sealing purpose can be achieved.

Description

Microporous gradient diffusion film device and application thereof

Technical Field

The invention relates to the technical field of environmental science, in particular to a microporous gradient diffusion film device and application thereof.

Background

As, Pb, Cd and other (similar) metal elements can be dissolved out from the Fe-containing minerals in the soil under the reducing condition and enter plants from root systems in a specific form. The plant effectiveness of these (metal-like) elements in soil is usually evaluated by soil digestion, but the total amount of these elements obtained by these methods does not represent the form and content of the elements that can be absorbed by plants.

The element morphology analysis is ectopic analysis, and because the analysis is difficult to ensure that the oxidation-reduction potential, the water content and other in-situ parameters in the water body do not change in the processes of acquisition, transportation, treatment and analysis, the plant effectiveness of the target element is difficult to truly reflect.

DGT is a new in-situ, non-destructive ion content measurement technique. The DGT technology is widely applied to the aspect of measuring the effective metal cations in water, soil and sediments, when the DGT technology is used for in-situ analysis of water, although the existing long-strip sampling probe can conveniently provide fine two-dimensional distribution of the effective content of the DGT and the interstitial water concentration of target elements in the soil, for water body evaluation and management, redundant detailed information also increases the use cost of the existing probe in large-scale use.

However, in the prior art, the thickness of the space for placing the DGT membrane assembly is fixed and unadjustable, so the application range is not wide, the reusability is not strong, and the sealing performance is not good.

Disclosure of Invention

In order to overcome the above-mentioned defects in the prior art, embodiments of the present invention provide a microporous gradient diffusion membrane device, and the technical problems to be solved by the present invention are: how to realize the thickness of the space of the DGT membrane assembly, and the sealing performance is good.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a micropore gradient diffusion film device, includes the base, the top fixedly connected with of base bears the seat, the top of bearing the seat is equipped with the DGT membrane module, the block has been cup jointed on the surface of bearing the seat, the top fixedly connected with clamping ring of block, the fixed surface of base is connected with the bearing, the fixed surface of bearing is connected with the drive circle, the top fixedly connected with thread bush of drive circle, the inner wall of thread bush and the surperficial swing joint of block.

When using, through placing the DGT membrane module at the top of bearing the seat, and cup joint the block on the surface of bearing the seat, until the surface of block and the inner wall contact of thread bush, through rotating the drive ring, thereby make the drive ring drive the thread bush and rotate, when the thread bush rotates, can make the inner wall of thread bush and the surface meshing of block, thereby make the thread bush can drive the block and reciprocate, thereby make the block drive clamping ring reciprocate, thereby change the thickness of placing DGT membrane module position space, and can tightly laminate the DGT membrane module at the top of bearing the seat when the clamping ring moves down, make can play sealed purpose.

In a preferred embodiment, the DGT membrane module comprises a filter membrane, a diffusion membrane, an adsorption membrane and a fixed membrane, arranged in sequence from top to bottom, the basic function of the diffusion membrane being to establish a water retention layer of defined thickness between the adsorption membrane and the filter membrane in an inert permeable material, so that soluble analytes smaller than the pore size of the permeable material can freely pass through the material at a certain rate and are finally irreversibly immobilized on the adsorption membrane, which is typically a product sold by DGTResearch Ltd, UK under the trade name R-GDR (pore size 2-5 nm), R-GDD (pore size 5-10 nm) or R-GDA (pore size 20-50 nm), which are mainly polyacrylamide compounds and agarose polymers, the adsorption membrane essentially serving to irreversibly and continuously absorb analytes which passively diffuse through the filter membrane and the diffusion membrane at a certain rate under monitoring conditions, the concentration of the test substance at the interface between the membrane and the membrane is kept constant at a specific value (usually far below the concentration in the ambient medium and operationally considered equal to 0), which is an adsorbent sold by DGTResearchLtd, UK under the trade name R-GDAG, SPR-IDA, R-GDFE or R-GDZR, respectively, and consisting of a polyacrylamide matrix and an adsorbent material in which silver iodide, SPR-IDA, iron oxide or zirconium oxide is embedded in the matrix, the filter membrane mainly serves to filter out suspended particles, colloids and bacteria in the ambient medium, to avoid clogging or destruction of the membrane by bacteria, and also as part of an inert diffusion membrane, which is typically a (polyethersulfone) filter membrane manufactured by PALL corporation, usa under product code 514-4156PES, having a thickness of 0.14 mm and a pore size of 0.45 microns. By definition, a permeable material with the same function can also be used as a filter membrane, such as the aforementioned PTFE, PVDF, GHP filter membranes, the basic function of the fixation membrane being to fix the whole DGT membrane module on top of the carrier bed.

In a preferred embodiment, the surface of the cap and the inner wall of the threaded sleeve are both provided with threads, and the inner wall of the threaded sleeve is in threaded connection with the surface of the cap, so that when the threaded sleeve is rotated, the threaded sleeve can drive the cap to move through the threaded connection between the inner wall of the threaded sleeve and the surface of the cap.

In a preferred embodiment, the inner wall of the cap is provided with a limiting groove, the inner wall of the limiting groove is connected with a limiting strip in a sliding manner, and the limiting strip is fixedly connected to the surface of the bearing seat, so that when the driving ring is rotated, the driving ring drives the threaded sleeve to rotate and is in threaded connection with the surface of the cap, the cap cannot be driven to rotate when the driving ring rotates, and therefore the cap can be driven to move up and down when the threaded sleeve rotates.

In a preferred embodiment, the movable groove has been seted up to the bottom of base, the inner wall fixedly connected with pivot in movable groove, the surface rotation of pivot is connected with the locating frame, the locating frame is D style of calligraphy structure for when using, through rotating the locating frame, and make and to carry out spacingly through handheld locating frame to the base, thereby the base does not have the impetus and drives the base pivoted condition when preventing the driving collar rotation.

In a preferred embodiment, the surface of the driving ring is provided with protruding strips, so that the contact area with a user can be increased, and the driving ring can be conveniently rotated.

In a preferred embodiment, the inner diameter of the pressing ring is smaller than the diameter of the DGT membrane assembly and the bearing seat, the diameter of the DGT membrane assembly is larger than the diameter of the bearing seat, and the diameter of the DGT membrane assembly is smaller than the inner diameter of the cover cap, so that the DGT membrane assembly can be tightly attached to the top of the bearing seat through the pressing ring in use, and therefore the DGT membrane assembly can play a role of sealing.

The invention also relates to the application of the device in detecting the content of different types of heavy metals in soil.

The DMA-DGT device of the present invention, when pre-processed and stored for transport prior to sampling, needs to be processed according to standard procedures specified in diffuisticationsite-files (DGT) for environmental measurement, 2016, published by cambridge university press, england. Before the device is assembled and used, it is packed in a thick plastic bag containing 15 ml of 0.01M NaNO3 solution and sealed by a heat sealer, so that the polyacrylamide or agarose hydrogel in the device is kept wet.

Methods for water sampling using the DMA-DGT device are described in the methods published by cambridge university press, england, under diffuis gradientthin-films (DGT) for environmental measurement (2016). The specific sampling method is as follows:

sampling time: any time is needed.

Sampling points: and 9 positions are uniformly distributed in the water.

DMA-DGT device setup: and (3) just putting 4 DMA-DGT devices into each sampling point, ensuring that the uppermost sampling layer of the device is positioned in the range of 0-5 cm below a water interface, and ensuring that the putting depths of four devices at the same sampling point are the same.

And (3) setting a thermometer: in each sample point, at the same depth near the DMA-DGT device location and as its middle sample layer, a button thermometer, sold by shanghai wadesen electronics ltd under model DS1922L, was placed with the read frequency set in advance. And simultaneously, two same button thermometers are arranged at the positions which are close to the No. 1 sampling point and respectively correspond to the uppermost sampling depth and the lowermost sampling depth.

The DMA-DGT device comprises the following steps before analysis after sampling:

the DMA-DGT device is taken back from the water body together with the button thermometer after one day of sampling;

the DMA-DGT device taken out is quickly scrubbed by tap water to remove the soil left on the surface of the window, and is placed in a common food self-sealing bag and sent back to a laboratory; then washing with pure water in a laboratory, and taking out the adsorption mold;

the recovered button thermometer was connected to a computer via an adapter (Shanghai Vodilesen electronics Co., Ltd., model DS9490R + DS1402), and the temperature change with time was read using Default1-Wirenet software. The insertion and extraction time points of the DMA-DGT device can be determined by the temperature jump when the button thermometer is put into and taken out of the water body, so that the placement time can be calculated.

In order to avoid non-uniform shrinkage of the adsorption mold during the dry pretreatment before analysis, it was treated according to the dry treatment method described in diffuisivegradientthin-films (dgt) for environmental measurement (2016), published by cambridge university press, england, uk. Specifically, the taken-out adsorption mold is flatly laid on the round PES filter membrane; then placing the filter membrane in a dryer; a piece of plastic cloth was laid flat over the sample and dried at 60 ℃ for 8 hours.

The total amount of the objects to be detected adsorbed by the miniature adsorption mould is too low, and the detection limit of the traditional elution and ICP-MS analysis method is too high, so that the adsorption mould adopts a LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) analysis method; SPR-IDA, R-GDFE and R-GDZR were analyzed. The size of an adsorption module in the DMA-DGT device is the same as that of a sampling window, and the adsorption module does not need to be cut before LA-ICP-MS analysis. The edges of the filter membrane need to be simply trimmed, the filter membrane and the adsorption mold are compounded, the filter membrane and the adsorption mold are pasted on a glass slide by using a double-sided adhesive tape, and then the filter membrane and the adsorption mold are pasted on a LA-ICP-MS sample chamber tray for analysis.

The preparation of LA-ICP-MS analysis standard curve needs to use the standard sample of adsorption mould. The preparation steps of the adsorption mold standard sample are as follows:

4 groups of 0.01 mol/l aqueous sodium chloride solutions, each of 2l, were prepared, containing 50, 100, 150, 200 μ g/l of the target compound to be tested. These solutions were stirred continuously overnight with a magnetic stirrer to bring the carbon dioxide and air in equilibrium. Conventional DGT units were placed in these solutions and stirred at 400rpm for 4 hours, and the solution temperatures at the beginning, middle and end were recorded.

Each amount of each target compound to be tested was loaded with 6 DGTs, three of which were used for routine ICP-MS analysis to determine the exact amount adsorbed on the adsorption membrane. The other three were used for standard curve analysis of LA-ICP-MS.

Before LA-ICP-MS analysis, cutting is needed to remove the part outside the sampling area so as to avoid the influence of edge diffusion effect. The sampling area is 3.14cm²The circular area of (a).

The cut samples were mounted on slides using high temperature resistant double sided tape and then placed in the LA sample chamber for analysis.

In order to optimize the analysis conditions, the instrument parameters need to be optimized from three aspects of ICP-MS, LA and carrier gas before analysis:

for the optimization of ICP-MS, the parameters of plasma and a lens of the ICP-MS are optimized under the condition of LA line scanning by using a glass standard sample, so that the monitored signals of elements such as U, Pb and the like reach the highest.

Optimizing LA and carrier gas parameters, using the prepared high-concentration Pb, As or Fe standard glue sample, and improving the ICP-MS signal value of the element to be detected in the glue As much As possible on the premise that the glue layer is not burnt out by laser by optimizing the laser energy, the ablation frequency and the scanning speed under the specific ablation spot size of LA; and finally, optimizing the flow rate of the aerosol helium carrier gas generated by the transport laser ablation to enable the signal value and the oxide proportion of the element to be measured of the ICP-MS to reach an ideal state.

The present invention uses a grid line pattern having an overall length of 1 cm to ablate the sample. A one-way trigger line from LA to ICP-MS is used to inform ICP-MS to start monitoring records synchronously at the start of LA ablation procedure, and to ensure synchronicity of operation between LA system and ICP-MS system when multiple samples are analyzed continuously, analysis parameters need to be set carefully so that the sampling period of each sample ICP-MS is longer than the preheat plus ablation time of LA, but shorter than the total LA period including the post-ablation gas path flush time.

In order to enable the LA-ICP-MS signal of the element to be detected in the sample to truly reflect the content of the element to be detected in the sample without being influenced by the degraded sample amount or the response state of a detector in LA-ICP-MS analysis, and considering that different DGT adsorption films all use polyacrylamide containing a carbon skeleton as a main substrate, 13C is used as an internal standard element in the scheme, and the original signal values of all the elements to be detected are divided by the corresponding 13C signal value to obtain a standardized signal value for subsequent analysis.

Further, in order to avoid the influence of structural damage and surface particle pollution on the analysis result in the preparation process of the standard glue sample, the invention utilizes a flow chart of C13 for standardizing the analysis quantity of the LA-ICP-MS, and firstly, a large number of standardized signal values of each glue standard sample are subjected to outlier elimination. After calculating the lower quartile (Q1), the upper quartile (Q3) and the quartile difference (IQR) from all the signal values of each sample, the normalized signal values greater than Q3+1.5IQR or less than Q1-1.5IQR were judged as outliers and discarded.

The invention utilizes LA-ICP-MS and standard glue samples to carry out quantitative analysis on standard curves of As, Pb and Fe. The amounts of As, Pb and Fe adsorbed and loaded on the standard gel and the average value of the normalized signals obtained by LA-ICP-MS analysis show a clear linear relationship, and R2 is respectively 0.998, 0.990 and 0.967.

Because the sampling frequency of the laser ablation system for the glue sample is not completely consistent with the reading frequency of the ICP-MS detector, and simultaneously, because the ablation mode used in the experiment is continuous line scanning, the overlapped ablation points cannot be directly used as the actual spatial resolution, a large amount of the obtained standardized signal value data needs to be segmented and packed, namely, a plurality of adjacent data points are averaged into one data, and the spatial resolution of LA-ICP-MS analysis is defined according to the data.

The invention has the technical effects and advantages that:

1. the driving ring is rotated to drive the threaded sleeve to rotate, so that the inner wall of the threaded sleeve is meshed with the surface of the nut cap, the threaded sleeve can drive the nut cap to move up and down, the nut cap drives the pressing ring to move up and down, the thickness of a space for placing a DGT (defected ground test) membrane assembly is changed, and the DGT membrane assembly can be tightly attached to the top of the bearing seat when the pressing ring moves downwards, so that the sealing purpose can be achieved;

2. prevent through only needing handheld locating frame that the base from rotating, and rotate the drive circle this moment for the drive circle passes through the thread bush and drives the block rebound, until the inner wall that the block breaks away from the thread bush, with the block take out can, convenient to detach, thereby realize convenient to detach reuse's purpose, compare with prior art, convenient to detach reuse.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a front sectional view of the overall structure of the present invention.

Fig. 3 is an elevational view of the overall construction of the present invention.

FIG. 4 is a top cross-sectional view of the cap structure of the present invention.

Fig. 5 is a bottom view of the base structure of the present invention.

FIG. 6 is a schematic structural view of a DGT membrane module of the present invention.

FIG. 7 is a front cross-sectional view of the overall structure of the second embodiment of the present invention.

FIG. 8 is a top view of a two-cellular board structure according to an embodiment of the present invention.

The reference signs are: 1. a base; 2. a bearing seat; 3. a DGT membrane module; 31. filtering the membrane; 32. a diffusion membrane; 33. adsorbing the mold; 34. fixing the film; 4. capping; 5. pressing a ring; 6. a limiting groove; 7. a limiting strip; 8. a bearing; 9. a drive coil; 10. a threaded sleeve; 11. a movable groove; 12. a rotating shaft; 13. a positioning frame; 14. a microporous plate; 15. and (4) micro-pores.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

The invention provides a microporous gradient diffusion film device which comprises a base 1, wherein the top of the base 1 is fixedly connected with a bearing seat 2, the top of the bearing seat 2 is provided with a DGT (defected ground test) film assembly 3, the surface of the bearing seat 2 is sleeved with a cover cap 4, the top of the cover cap 4 is fixedly connected with a pressing ring 5, the surface of the base 1 is fixedly connected with a bearing 8, the surface of the bearing 8 is fixedly connected with a driving ring 9, the top of the driving ring 9 is fixedly connected with a threaded sleeve 10, and the inner wall of the threaded sleeve 10 is movably connected with the surface of the cover cap 4.

The DGT membrane component 3 comprises a filter membrane 31, a diffusion membrane 32, an adsorption membrane 33 and a fixed membrane 34, wherein the filter membrane 31, the diffusion membrane 32, the adsorption membrane 33 and the fixed membrane 34 are sequentially arranged from top to bottom.

The surface of the cap 4 and the inner wall of the threaded sleeve 10 are both provided with threads, and the inner wall of the threaded sleeve 10 is in threaded connection with the surface of the cap 4.

The inner wall of the cap 4 is provided with a limit groove 6, the inner wall of the limit groove 6 is connected with a limit strip 7 in a sliding manner, and the limit strip 7 is fixedly connected to the surface of the bearing seat 2.

The bottom of base 1 has seted up activity groove 11, the inner wall fixedly connected with pivot 12 of activity groove 11, the surface of pivot 12 is rotated and is connected with locating frame 13, locating frame 13 is the D style of calligraphy structure.

The surface of the driving ring 9 is provided with a convex strip.

The inner diameter of the pressing ring 5 is smaller than the diameters of the DGT membrane assembly 3 and the bearing seat 2, the diameter of the DGT membrane assembly 3 is larger than the diameter of the bearing seat 2, and the diameter of the DGT membrane assembly 3 is smaller than the inner diameter of the cover cap 4.

As shown in fig. 1 to 6, the embodiment specifically is: when the DGT membrane component is used, the DGT membrane component 3 is placed at the top of the bearing seat 2, the cap 4 is sleeved on the surface of the bearing seat 2 until the surface of the cap 4 is in contact with the inner wall of the threaded sleeve 10, the driving ring 9 is rotated, the driving ring 9 drives the threaded sleeve 10 to rotate, when the threaded sleeve 10 rotates, the inner wall of the threaded sleeve 10 is meshed with the surface of the cap 4, the threaded sleeve 10 can drive the cap 4 to move up and down, the cap 4 drives the pressing ring 5 to move up and down, the thickness of a space where the DGT membrane component 3 is placed is changed, and the DGT membrane component 3 can be tightly attached to the top of the bearing seat 2 when the pressing ring 5 moves downwards, so that the sealing purpose can be achieved Poor reusability and poor sealing performance;

through setting up locating frame 13, and locating frame 13 can accomodate the inside of advancing activity groove 11, make locating frame 13 not hinder base 1's normal prevention, and through rotating locating frame 13, and handheld locating frame 13 can be spacing to base 1, thereby base 1 does not have the impetus when preventing that drive ring 9 from rotating and drives base 1 pivoted condition, and when needs are dismantled, only need handheld locating frame 13 to prevent base 1 from rotating, and rotate drive ring 9 this moment, make drive ring 9 drive the inner wall that the block 4 upwards moved through thread bush 10, until block 4 breaks away from thread bush 10, take out block 4 can, be convenient for dismantle, this embodiment has specifically solved the dismantlement problem of being not convenient for that exists among the prior art.

Example two

Different from the first embodiment, the inner wall of the pressing ring 5 is fixedly connected with a microporous plate 14, the middle part of the microporous plate 14 is provided with a plurality of micropores 15, the micropores 15 are cylindrical holes with a sectional area of 0.196cm2 and a depth of 1mm, and certainly, the sectional area and the depth of the micropores can be adjusted in a fine manner according to actual needs.

As shown in fig. 7 to 8, the embodiment specifically is: the multi-point monitoring can be carried out on different kinds of heavy (similar) metals through the plurality of micropores 15 in the microporous plate 14 on the inner wall of the pressing ring 5, so that the multi-point detection can be realized, and the embodiment specifically solves the problem that the multi-point detection cannot be carried out in the prior art.

sampling time: any time is needed.

Sampling points: and 9 positions are uniformly distributed in the water.

the DMA-DGT device taken out is quickly scrubbed by tap water to remove the soil left on the surface of the window, and is placed in a common food self-sealing bag and sent back to a laboratory; then, the sample is washed with pure water in a laboratory, and then the adsorption mold 33 is taken out;

In order to avoid non-uniform shrinkage of the adsorption mold 33 during the drying pretreatment before analysis, it was treated according to the drying treatment method described in diffuisticationthin-films (dgt) for environmental measurement (2016), published by cambridge university press, england. Specifically, the adsorption mold 33 taken out is laid flat on the circular PES filter membrane 31; then placing the filter membrane 31 in a dryer; a piece of plastic cloth was laid flat over the sample and dried at 60 ℃ for 8 hours.

The total amount of the objects to be detected adsorbed by the miniaturized adsorption module 33 is too low, and the detection limit of the traditional elution and ICP-MS analysis method is too high, so that the adsorption module 33 adopts an LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) analysis method; SPR-IDA, R-GDFE and R-GDZR were analyzed. The size of the adsorption mode 33 in the DMA-DGT device is the same as that of a sampling window, and the adsorption mode 33 does not need to be cut before LA-ICP-MS analysis. The edges of the filter membrane 31 are simply trimmed, the filter membrane 31 is combined with the adsorption mold 33, and the filter membrane 31 and the adsorption mold are adhered to a glass slide by using a double-sided adhesive tape and then adhered to a LA-ICP-MS sample chamber tray for analysis.

A standard LA-ICP-MS analysis curve is prepared by using a standard sample of the adsorption mold 33. The preparation steps of the adsorption mold 33 standard sample are as follows:

The working principle of the invention is as follows:

referring to the attached drawings 1-6 in the specification, the driving ring 9 is rotated to enable the driving ring 9 to drive the threaded sleeve 10 to rotate, so that the inner wall of the threaded sleeve 10 is meshed with the surface of the cap 4, the threaded sleeve 10 can drive the cap 4 to move up and down, the cap 4 drives the pressing ring 5 to move up and down, the thickness of a space for placing the DGT membrane assembly 3 is changed, and when the pressing ring 5 moves downwards, the DGT membrane assembly 3 is tightly attached to the top of the bearing seat 2, so that the sealing purpose can be achieved;

referring to the attached drawings 1-6 of the specification, the base 1 is prevented from rotating only by holding the positioning frame 13 by hand, and at the moment, the driving ring 9 is rotated, so that the driving ring 9 drives the cap 4 to move upwards through the threaded sleeve 10 until the cap 4 is separated from the inner wall of the threaded sleeve 10, the cap 4 is taken out, the disassembly is convenient, and the aim of convenient disassembly and reutilization is fulfilled.

The points to be finally explained are: first, in the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may be a mechanical connection or an electrical connection, or a communication between two elements, and may be a direct connection, and "upper," "lower," "left," and "right" are only used to indicate a relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship may be changed;

secondly, the method comprises the following steps: in the drawings of the disclosed embodiments of the invention, only the structures related to the disclosed embodiments are referred to, other structures can refer to common designs, and the same embodiment and different embodiments of the invention can be combined with each other without conflict;

and finally: the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.

Claims

1. A microporous gradient diffusion membrane device, comprising a base (1), characterized in that: the top fixedly connected with of base (1) bears seat (2), the top that bears seat (2) is equipped with DGT membrane module (3), cap (4) have been cup jointed on the surface that bears seat (2), top fixedly connected with clamping ring (5) of cap (4), the fixed surface of base (1) is connected with bearing (8), the fixed surface of bearing (8) is connected with drive ring (9), the top fixedly connected with thread bush (10) of drive ring (9), the inner wall of thread bush (10) and the surface swing joint of cap (4).

2. A microporous gradient diffusion membrane device according to claim 1, wherein: the DGT membrane component (3) comprises a filter membrane (31), a diffusion membrane (32), an adsorption membrane (33) and a fixed membrane (34), wherein the filter membrane (31), the diffusion membrane (32), the adsorption membrane (33) and the fixed membrane (34) are sequentially arranged from top to bottom.

3. A microporous gradient diffusion membrane device according to claim 1, wherein: the surface of the cover cap (4) and the inner wall of the threaded sleeve (10) are both provided with threads, and the inner wall of the threaded sleeve (10) is in threaded connection with the surface of the cover cap (4).

4. A microporous gradient diffusion membrane device according to claim 1, wherein: spacing groove (6) have been seted up to the inner wall of block (4), the inner wall sliding connection of spacing groove (6) has spacing (7), and spacing (7) fixed connection is on the surface that bears seat (2).

5. A microporous gradient diffusion membrane device according to claim 1, wherein: activity groove (11) have been seted up to the bottom of base (1), the inner wall fixedly connected with pivot (12) of activity groove (11), the surface of pivot (12) is rotated and is connected with locating frame (13), locating frame (13) are D style of calligraphy structure.

6. A microporous gradient diffusion membrane device according to claim 1, wherein: and convex strips are arranged on the surface of the driving ring (9).

7. A microporous gradient diffusion membrane device according to claim 1, wherein: the inner diameter of the pressing ring (5) is smaller than the diameters of the DGT membrane assembly (3) and the bearing seat (2), the diameter of the DGT membrane assembly (3) is larger than the diameter of the bearing seat (2), and the diameter of the DGT membrane assembly (3) is smaller than the inner diameter of the cover cap (4).

8. Use of the device according to any one of claims 1-7 for detecting the content of different kinds of heavy metals in a water body.