1. A novel sampling strip for detecting PM2.5 concentration in environment is characterized by comprising an adsorption layer and a substrate layer, wherein the adsorption layer is made of graphene-based materials, and the substrate layer is made of sparse porous materials.

2. The novel sampling strip for detecting PM2.5 concentration in an environment as claimed in claim 1, wherein said graphene-based material comprises graphene, graphene oxide.

3. The novel sampling strip for detecting PM2.5 concentration in an environment of claim 1, wherein said sparse porous material comprises PET coarse screen, fiberglass coarse filter paper.

4. The novel sampling strip structure for detecting PM2.5 concentration in environment as claimed in claim 1, wherein the adsorption layer is attached to the substrate layer or embedded in the substrate layer.

5. The novel sampling strip structure for detecting PM2.5 concentration in an environment as claimed in claim 1, wherein the thickness of the adsorption layer is 5-100 μm.

6. The novel method for manufacturing the sampling strip for detecting the PM2.5 concentration in the environment as claimed in any one of claims 1 to 5, characterized by comprising the following steps:

(1) preparing an adsorption layer material dispersion liquid:

(2) lining the filter with a layer of filter paper:

(3) placing a layer of substrate layer material on the filter paper:

(4) pouring the suspension solution obtained in the step (1) into the filter device assembled in the step (3):

(5) accelerating the filtration of the suspension solution obtained in step (1) using an accelerated filtration process to obtain a substrate layer material of a wet cover adsorbent layer material:

(6) drying the substrate layer material of the wet covering adsorption layer material obtained in the step (5) to obtain a dried substrate layer material of the covering adsorption layer material, and finishing a sampling strip of which the adsorption layer is attached to the substrate layer structure;

(7) and (4) placing the sampling strip of which the adsorption layer is attached to the substrate layer structure obtained in the step (6) on a flat plane, enabling the adsorption layer to be upward, covering another substrate layer material on the adsorption layer material to form a substrate layer-adsorption layer-substrate layer structure, and sealing the upper substrate layer and the lower substrate layer to form the sampling strip of which the adsorption layer is embedded in the substrate layer structure.

7. The novel method for manufacturing the sampling strip for detecting the concentration of PM2.5 in the environment according to claim 6, wherein the solution concentration of the dispersion liquid of the adsorption layer material obtained in the step (1) is 10-0.5 mg/ml.

8. The novel method for manufacturing the sampling strip for detecting the concentration of PM2.5 in the environment according to claim 6, wherein the volume of the suspension solution used in the step (4) is 50-1000 ml.

9. The novel manufacturing method of the sampling strip for detecting the concentration of PM2.5 in the environment according to claim 6, characterized in that the filtering acceleration method used in the step (5) is a negative pressure suction filtration method, and the sealing method used in the step (7) is a glue sealing method.

10. The use of the novel sampling strip of any one of claims 1 to 5 for detecting PM2.5 concentration in an environment in Beta-ray attenuation dust detection.

Background

PM2.5 refers to particles having an aerodynamic equivalent diameter of 2.5 microns or less in ambient air. The PM2.5 has small particle size, is easy to attach toxic and harmful substances, and has long retention time in the atmosphere, thereby having great influence on the human health and the quality of the atmospheric environment. In the new "environmental air quality standard" implemented in 2016, PM2.5 was a necessary statistical target for the air pollution index.

Currently, methods for calculating PM2.5 in air include the following three methods: gravimetric, beta ray attenuation and micro-oscillation balance. In all three methods, PM2.5 of a certain volume of gas to be detected is trapped in a filter membrane through a filtering method, and then the amount of PM2.5 in the filter membrane is counted to obtain the concentration of PM2.5 in the gas to be detected. Wherein the gravimetric method calculates the amount of PM2.5 by weighing the mass change of the filter membrane before and after filtration. According to the energy loss principle caused by the fact that beta rays penetrate through materials, after PM2.5 is adsorbed by the filter membrane, the attenuation capacity of the filter membrane on the beta rays is increased, and the PM2.5 quantity is calculated by calculating the energy attenuation change of the beta rays. The micro-oscillation balance method is to place the filter membrane material on an oscillator and excite the oscillator to generate oscillation through an electric field. When the filter membrane absorbs PM2.5, the filter membrane is weighted so as to change the mass of the whole oscillator, and the oscillation frequency is changed. And calculating the frequency change to obtain the mass of PM2.5 on the filter membrane so as to calculate the content of PM2.5 in the gas to be detected. Currently, a mainstream PM2.5 measuring device in the market generally adopts a beta ray attenuation method for measurement.

No matter which detection method is adopted, the filter membrane is a core component, and the adsorption capacity of the filter membrane on PM2.5 directly influences the accuracy of measurement. The materials for adsorbing PM2.5 in the market at present comprise glass fiber, polypropylene melt-blown fabric, polyester resin and the like. The adsorption capacity of the PM2.5 adsorbing material for the PM2.5 is mainly embodied in the specific surface area of the material. With the development of the scientific field, the specific surface area of the materials used in the market gradually loses advantages.

Currently, the adsorption strip material used in the market is blank glass fiber filter paper. The material has better strength and adsorbability, but the thicker material per se has stronger beta ray absorption, so the calculation accuracy is lower when the beta ray method is used for calculating PM2.5 particles. The existing research shows that the interception capability of the pure polyacrylonitrile fiber material to PM2.5 reaches 93.36%, and the interception capability of the graphene oxide-polyacrylonitrile composite material prepared by doping graphene oxide with the mass concentration of 0.5% to PM2.5 reaches 99.97%, so that the detection accuracy is greatly improved. (hanging Li. Dazhen zhang. Nanofibrous Membrane of graphene oxide-in-polyacrylic composition with low filtering resistance for the effective capture of PM2.5.journal of Membrane science 2018.551, 85-92.).

Disclosure of Invention

In order to solve the problems that in the prior art, the material has strong absorption on beta rays and poor adsorption capacity on PM2.5 particles, so that the detection sensitivity on PM2.5 particles is low, the invention provides a novel sampling strip for detecting the concentration of PM2.5 in an environment, and the graphene-based adsorption layer is adopted, so that the detection sensitivity is high, and the western-style clothes for PM2.5 particles have strong capacity.

The technical scheme is as follows: a novel sampling strip for detecting PM2.5 concentration in environment comprises an adsorption layer and a substrate layer, wherein the adsorption layer is made of graphene-based materials, and the substrate layer is made of sparse porous materials.

The graphene-based material comprises graphene and graphene oxide.

The sparse porous material comprises a PET material coarse filter screen and glass fiber coarse filter paper.

The adsorption layer is attached to the substrate layer or embedded in the substrate layer.

The thickness of the adsorption layer is 5-100 microns.

The novel manufacturing method of the sampling strip for detecting the PM2.5 concentration in the environment comprises the following steps:

(1) preparing an adsorption layer material dispersion liquid:

(2) lining the filter with a layer of filter paper:

(3) placing a layer of substrate layer material on the filter paper:

(4) pouring the suspension solution obtained in the step (1) into the filter device assembled in the step (3):

(5) accelerating the filtration of the suspension solution obtained in step (1) using an accelerated filtration process to obtain a substrate layer material of a wet cover adsorbent layer material:

(6) and (5) drying the substrate layer material of the wet covering adsorption layer material obtained in the step (5) to obtain the substrate layer material of the dry covering adsorption layer material, and finishing the sampling strip of which the adsorption layer is attached to the substrate layer structure.

(7) And (4) placing the sampling strip of which the adsorption layer obtained in the step (6) is attached to the substrate layer structure on a flat plane, wherein the adsorption layer is upward in material. Another substrate layer material is covered on the adsorption layer material to form a substrate layer-adsorption layer-substrate layer structure, the upper substrate layer and the lower substrate layer are sealed, and a sampling strip with the adsorption layer embedded in the substrate layer structure is formed.

The solution concentration of the dispersion liquid of the material of the adsorption layer obtained in the step (1) is 10-0.5 mg/ml.

The volume of the suspension solution used in the step (4) is 50-1000 ml.

And (5) the filtering acceleration method used in the step (5) is a negative pressure suction filtration method.

The sealing method used in the step (7) is a glue sealing method.

The novel sampling strip for detecting the PM2.5 concentration in the environment is applied to the dust detection by the beta ray attenuation method.

Has the advantages that:

the graphene material is adopted as the adsorption layer, is composed of carbon elements, and has the characteristics of high specific surface area and low material atomic number. The characteristic of high specific surface area can enhance the adsorption capacity of the graphene to PM2.5, and the characteristic of low atomic number of the material can reduce the attenuation influence of the filter membrane on beta rays, thereby improving the detection precision of PM2.5.

The thickness of the substrate layer material of the cover adsorption layer material dried in step (6) of the present invention is determined by the concentration of the solution prepared in step (1) and the volume of the solution used in step (4).

Drawings

Fig. 1 is a top view of a novel sampling strip structure of an adsorption structure for detecting PM2.5 concentration in an environment.

FIG. 2 is a side view of a novel sampling strip configuration of an adsorbent structure for detecting PM2.5 concentrations in an environment.

1-adsorption layer and 2-substrate layer.

Fig. 3 is a surface photograph under an electron microscope after PM2.5 is adsorbed by graphene.

Detailed Description

Example 1

Firstly, 200mg of graphene powder is added into 100ml of deionized water, and the graphene powder is ultrasonically dispersed into 2mg/ml of dispersion liquid by using an ultrasonic machine with the power of 40 w.

And secondly, selecting a set of suction filtration device, and placing a layer of filter paper on a funnel in the filtration device.

And thirdly, taking a section of PET coarse filter screen, and superposing the PET coarse filter screen on the filter paper in the second step in a single-layer structure.

And fourthly, pouring 100ml of the 2mg/ml dispersion prepared in the first step into a funnel, performing suction filtration by using a differential pump, and removing filter paper after the suction filtration is completed to obtain the graphene-containing PET coarse filter screen.

And fifthly, putting the PET coarse filter screen with the graphene obtained in the fourth step into an oven, baking for 30 minutes at 150 ℃, and drying, wherein the adsorption layer is 80 microns, and the adsorption area is about 20 square centimeters.

Example 2

Firstly, adding 25mg of graphene oxide powder into 100ml of deionized water, and ultrasonically dispersing into 0.25mg/ml of dispersion liquid by using an ultrasonic machine with the power of 40 w.

And secondly, selecting a set of suction filtration device, and placing a layer of filter paper on a funnel in the filtration device.

And thirdly, taking a section of glass fiber rough filter paper, and superposing the glass fiber rough filter paper on the filter paper in the second step in a single-layer structure.

And fourthly, pouring 100ml of 0.25mg/ml dispersion prepared in the first step into a funnel, performing suction filtration by using a differential pump, and removing the filter paper after the suction filtration is completed to obtain the glass fiber rough filter paper with the graphene oxide.

And fifthly, putting the glass fiber coarse filter paper with the graphene oxide obtained in the fourth step into an oven, baking for 30 minutes at 150 ℃, and drying, wherein the thickness of an adsorption layer is 10 micrometers, and the adsorption area is about 20 square centimeters.

Example 3

Firstly, 125mg of graphene oxide powder is added into 100ml of deionized water, and the mixture is ultrasonically dispersed into 1.25mg/ml of dispersion liquid by using an ultrasonic machine with the power of 40 w.

And secondly, selecting a set of suction filtration device, and placing a layer of filter paper on a funnel in the filtration device.

And thirdly, taking the area of a section of glass fiber coarse filter paper, and superposing the area of the glass fiber coarse filter paper on the filter paper in the second step in a single-layer structure.

And fourthly, pouring 100ml of the 1.25mg/ml dispersion prepared in the first step into a funnel, performing suction filtration by using a differential pump, and removing the filter paper after the suction filtration is completed to obtain the glass fiber rough filter paper with the graphene oxide.

And fifthly, putting the glass fiber coarse filter paper with the graphene oxide obtained in the fourth step into an oven, baking for 30 minutes at 150 ℃, and drying, wherein the thickness of an adsorption layer is 50 micrometers, and the adsorption area is about 20 square centimeters.

And sixthly, placing the dried glass fiber coarse filter paper with the graphene oxide obtained in the fifth step on a flat plane, enabling the graphene oxide to face upwards, covering another piece of glass fiber coarse filter paper on the graphene oxide, coating UV curing glue on the edges of the upper and lower glass fiber coarse filter papers which are not covered with the graphene oxide, and irradiating the UV curing glue by using an ultraviolet lamp to cure the UV curing glue.

Table 1 shows some of the physical properties of the two adsorbent layer materials.

The novel PM2.5 sampling strip is simple in preparation method and good in using effect, and has the characteristic of high precision compared with the existing similar materials.