阅读说明：本技术 负载荧光指示剂制备溶解氧传感器氧敏感膜的方法及应用 (Method for preparing oxygen sensitive membrane of dissolved oxygen sensor by loading fluorescent indicator and application ) 是由 魏伟 刘瑞杰 张旭 于 2021-08-06 设计创作，主要内容包括：本发明公开了负载荧光指示剂制备溶解氧传感器氧敏感膜的方法及应用,包括透明支撑层的活化处理、荧光层的制备、折射层的制备和遮光保护层的制备,在荧光层制备中,荧光指示剂在与纳米材料的混合过程中会被吸附包裹在高透、高折射率的纳米材料中,通过聚二甲基硅氧烷固定在透明支撑层上形成稳定的荧光层,在荧光层上引入折射层,可以使传感器的测量光与荧光物质充分接触,在折射层上沉积遮光保护层,遮光保护层中使用了可以改善氧敏感膜机械强度的纳米材料,减少氧敏感膜在使用过程中受到的冲击与损坏,提高负载荧光指示剂制备溶解氧传感器氧敏感膜的使用寿命。(The invention discloses a method for preparing a dissolved oxygen sensor oxygen-sensitive membrane by loading a fluorescent indicator and application thereof, which comprises the steps of activation treatment of a transparent supporting layer, preparation of a fluorescent layer, preparation of a refraction layer and preparation of a shading protective layer, in the preparation of the fluorescent layer, the fluorescent indicator can be absorbed and wrapped in the nano material with high transmittance and high refractive index in the mixing process of the fluorescent indicator and the nano material, and is fixed on the transparent supporting layer through the polydimethylsiloxane to form a stable fluorescent layer, the introduction of the refraction layer on the fluorescent layer can make the measuring light of the sensor fully contact with the fluorescent material, the shading protective layer is deposited on the refraction layer, and the nanometer material capable of improving the mechanical strength of the oxygen sensitive film is used in the shading protective layer, so that the impact and damage of the oxygen sensitive film in the using process are reduced, and the service life of the dissolved oxygen sensor oxygen sensitive film prepared by loading the fluorescent indicator is prolonged.)

1. The method for preparing the oxygen sensitive membrane of the dissolved oxygen sensor by loading the fluorescent indicator is characterized by comprising the following steps:

s1: activation treatment of the transparent support layer (4): activating and processing the transparent supporting layer (4) by using a rotary low-temperature plasma surface processor;

s2: preparation of the fluorescent layer (3): mixing the nano material A, a fluorescent indicator, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment for 30min, stirring for 6-12 h to obtain fluorescent layer slurry, and coating the fluorescent layer slurry on a transparent supporting layer (4) in S1 to form a fluorescent layer (3);

s3: preparation of the refractive layer (2): mixing the nano material A, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment, stirring for 6-12 h to obtain refraction layer slurry, and coating the refraction layer slurry on the fluorescent layer (3) in S2 to form a refraction layer (2);

s4: preparing a shading protective layer (1): mixing the nano material B, carbon black, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment to obtain shading protective layer slurry, and coating the shading protective layer slurry on the refraction layer (2) in S3 to form a shading protective layer (1).

2. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: the nano material A is one or more of nano aluminum oxide, nano boron nitride, nano zirconium oxide and nano silicon dioxide, and the fluorescence indicator is one or more of platinum (II) MESO-tetra (pentafluorobenzene) porphine, tris (2, 2-bipyridyl) ruthenium dichloride, octaethylplatinum porphyrin and tris (5-amino-1, 10-phenanthroline) ruthenium dichloride.

3. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: in step S2, the content ratio of the fluorescent indicator A to the nano material A is 1% -5%, and the content of the nano material A in the fluorescent layer (3) is 3% -6%; in step S3, the content of the nanomaterial a in the refraction layer (2) is 5% to 10%.

4. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: in step S4, the content of the nanomaterial B in the light-shielding protective layer (1) is 5% to 9%, the content of the carbon black in the light-shielding protective layer (1) is 1% to 5%, and the nanomaterial B is one or more of nano silicon carbide, nano tungsten carbide, and nano titanium carbide.

5. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: the volatile alkane is one or more of n-hexane, n-heptane and cyclohexane.

6. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: the transparent supporting layer (4) is made of transparent acrylic resin, the thickness of the fluorescent layer (3) is 15-60 mu m, the thickness of the refraction layer (2) is 15-60 mu m, and the thickness of the shading protective layer (1) is 15-60 mu m.

7. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 1, wherein: the fluorescence indicator is one or more of platinum (II) MESO-tetra (pentafluorobenzene) porphin quantum dots, tris (2, 2-bipyridyl) ruthenium dichloride quantum dots, octaethylplatinum porphyrin quantum dots and tris (5-amino-1, 10 phenanthroline) ruthenium dichloride quantum dots.

8. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 7, wherein: in step S2, the nanomaterial a is one or more of mesoporous silica, mesoporous alumina, and mesoporous zirconia, the mesoporous silica has a radial wrinkle structure, and the pore diameter of the mesoporous silica is 5-30 nm.

9. The method of preparing a dissolved oxygen sensor oxygen-sensitive membrane loaded with a fluorescent indicator according to claim 7, wherein: the nano material B is nano activated carbon fiber composite titanium carbide, and the nano activated carbon fiber is subjected to modification treatment.

10. Use of an oxygen sensitive film prepared according to the process of any one of claims 1 to 9, wherein: the oxygen-sensitive film is applied to a dissolved oxygen sensor and used for detection of dissolved oxygen.

Technical Field

The invention relates to the technical field of environmental monitoring, in particular to a method for preparing an oxygen sensitive membrane of a dissolved oxygen sensor by loading a fluorescent indicator and application thereof.

Background

Dissolved oxygen is used as one of comprehensive indexes for evaluating water quality and one of important indexes for evaluating the degree of organic matter pollution of water body, research on a dissolved oxygen detection sensing technology is developed by means of combining electrochemistry and electronic science in many countries, and various methods and instruments for measuring the dissolved oxygen are derived from the synthesis of disciplines.

Most of the products sold in the market at present are based on a polarographic dissolved oxygen electrode diffusion current measuring method, but an online oxygen electrode is adopted, the electrode is always electrified (even under the condition of shutdown), the electrode loss is large, the electrode needs to be replaced frequently, the maintenance amount and the maintenance cost are greatly increased, and the electrode is frequently damaged due to frequent maintenance. Fluorescent fiber sensors have also been studied abroad, but few products are currently marketed. The product is based on a fluorescence quenching principle, has accurate measurement and short response time, but has larger technical barrier, and is particularly embodied on a fluorescent film, so that the dissolved oxygen sensitive film with simple preparation process and high performance is provided, which is a difficult problem to solve in the field. At present, there are many relevant researches on a fluorescent dissolved oxygen sensitive film, and there are many relevant patents, for example, chinese patent document CN106353292A discloses a method for preparing a fluorescent sensitive film using a sol-gel, and chinese patent document CN108918476A discloses a method for preparing a dissolved oxygen fluorescent film using a high molecular polymer polyvinyl chloride to prepare an oxygen sensitive film.

In the process of preparing the oxygen-sensitive fluorescent film by the existing sol-gel method, the fixing method of the oxygen-sensitive fluorescent indicator generally comprises two methods of physical embedding and chemical bonding. The physical embedding method is to directly disperse the indicator into the precursor solution according to a proper proportion, spread the indicator on the surface of the substrate by methods such as spin coating or dipping, and obtain the oxygen-sensitive fluorescent film after drying. In the film produced by this method, the indicator molecules have weak forces (usually van der waals forces, hydrogen bonds, electrostatic forces, etc.) with the matrix network, and thus the indicator molecules easily leak out of the matrix.

Therefore, the common weaknesses of the dissolved oxygen sensitive membrane prepared in the prior art are that the response speed is slow, the interaction between the fluorescent indicator and the substrate is weak, and the fluorescent indicator can be lost due to various reasons, such as solvent, temperature, solution, pH and the like, in the using process.

Disclosure of Invention

The invention aims to provide a method for preparing an oxygen sensitive membrane of a dissolved oxygen sensor by loading a fluorescent indicator and application thereof, so as to solve the problems in the prior art.

In order to solve the technical problems, the invention provides the following technical scheme:

the method for preparing the oxygen sensitive film of the dissolved oxygen sensor by loading the fluorescent indicator comprises the following steps:

s1: activating the transparent support layer: activating and treating the transparent supporting layer by using a rotary low-temperature plasma surface treating machine;

s2: preparation of a fluorescent layer: mixing the nano material A, a fluorescent indicator, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment for 30min, stirring for 6-12 h to obtain fluorescent layer slurry, and coating the fluorescent layer slurry on the transparent supporting layer in S1 to form a fluorescent layer;

s3: preparation of the refractive layer: mixing the nano material A, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment, stirring for 6-12 hours to obtain refraction layer slurry, and coating the refraction layer slurry on the fluorescent layer in S2 to form a refraction layer;

s4: preparing a shading protective layer: mixing the nanometer material B, carbon black, polydimethylsiloxane and volatile alkane, then carrying out ultrasonic treatment to obtain shading protective layer slurry, and coating the shading protective layer slurry on the refraction layer in S3 to form a shading protective layer.

Preferably, the nanomaterial A is one or more of nano aluminum oxide, nano boron nitride, nano zirconium oxide and nano silicon dioxide, and the fluorescence indicator is one or more of platinum (II) MESO-tetra (pentafluorobenzene) porphine, tris (2, 2-bipyridine) ruthenium dichloride, octaethylplatinum porphyrin and tris (5-amino-1, 10-phenanthroline) ruthenium dichloride.

The fluorescence indicator can be adsorbed and coated in the high-transmittance and high-refractive-index nano material A in the mixing process of the fluorescence indicator and the nano material A, the loss of the fluorescence indicator is reduced, the polydimethylsiloxane enables the nano material A coated with the fluorescence indicator to be fixed on the transparent supporting layer to form a stable fluorescent layer, the fluorescent layer is irradiated by exciting light to generate fluorescence, the emitted fluorescence is sensitive to oxygen, and the oxygen concentration or molecular oxygen in water can be represented and calculated through a fluorescence quenching mechanism.

Preferably, in step S2, the content ratio of the fluorescent indicator to the nanomaterial a is 1% to 5%, and the content of the nanomaterial a in the fluorescent layer is 3% to 6%.

In step S3, the content of the nanomaterial a in the refraction layer is 5% to 10%, and the introduction of the refraction layer makes the measurement light of the sensor fully contact with the fluorescent substance.

Preferably, in step S4, the content of the nanomaterial B in the light-shielding protective layer is 5% to 9%, the content of the carbon black in the light-shielding protective layer is 1% to 5%, the nanomaterial B is one or more of nano silicon carbide, nano tungsten carbide and nano titanium carbide, and the addition of the nanomaterial B improves the mechanical strength of the dissolved oxygen sensor oxygen-sensitive membrane prepared by loading the fluorescence indicator.

Preferably, the volatile alkane is one or more of n-hexane, n-heptane and cyclohexane.

Preferably, the transparent supporting layer is made of transparent acrylic resin, the thickness of the fluorescent layer is 15-60 μm, the thickness of the refraction layer is 15-60 μm, and the thickness of the shading protective layer is 15-60 μm.

Preferably, the fluorescence indicator is one or more of platinum (II) MESO-tetra (pentafluorobenzene) porphine quantum dots, tris (2, 2-bipyridyl) ruthenium dichloride quantum dots, octaethylplatinum porphyrin quantum dots and tris (5-amino-1, 10 phenanthroline) ruthenium dichloride quantum dots.

Preferably, in step S2, the nanomaterial a is one or more of mesoporous silica, mesoporous alumina, and mesoporous zirconia; the mesoporous silica has a radial fold structure, and the aperture of the mesoporous silica is 5-30 nm.

Preferably, the preparation method of the mesoporous silica with the radial fold structure comprises the following steps: dissolving 0.1g of cetrimide into 14ml of deionized water at the temperature of 20-25 ℃, adding 3ml of ethanol, 3ml of diethyl ether and 0.3ml of ammonia water, mixing and stirring for 40-60 minutes, dropwise adding 0.5ml of ethyl orthosilicate and 0.045ml of 3-mercapto-1-propanesulfonic acid sodium salt, continuously stirring for 6-8 hours, repeatedly washing precipitates with ethanol and deionized water, drying to obtain a sample, and crushing the sample to obtain the mesoporous silica with the radial fold structure.

The mesoporous silica with the radial fold structure is used, the specific surface area of the nano material is increased as much as possible, and the fluorescent indicator is fixed on the surface of the porous material after being subjected to the protonation treatment, so that the response speed of the fluorescent indicator to oxygen molecules can be greatly increased, and the loss of the fluorescent indicator is greatly reduced.

Preferably, the nano material B is nano activated carbon fiber composite titanium carbide, and the nano activated carbon fiber is subjected to modification treatment.

Preferably, the preparation method of the activated carbon fiber composite titanium carbide comprises the following steps: soaking activated carbon fibers in a zinc acetate solution, then carrying out ultrasonic treatment, carrying out vacuum impregnation treatment on the obtained product, repeating the ultrasonic treatment and the vacuum impregnation treatment, taking out the product and drying the product to obtain modified activated carbon fibers, dripping a solution obtained by mixing and stirring absolute ethyl alcohol, acetic acid and deionized water into a mixed solution of the absolute ethyl alcohol, the acetic acid and tetrabutyl titanate under vigorous stirring, continuing stirring after dripping is finished, and aging and standing at the temperature of 20-25 ℃ to obtain a sol of a titanium carbide precursor;

and soaking the modified activated carbon fiber in the sol, performing ultrasonic treatment, performing vacuum impregnation treatment on the obtained product, repeating the ultrasonic treatment and the vacuum impregnation treatment, taking out and drying the product, and crushing the product after roasting to obtain the activated carbon fiber composite titanium carbide.

The zinc acetate modified activated carbon fiber composite titanium carbide improves the wear resistance and corrosion resistance of the dissolved oxygen sensor oxygen-sensitive membrane, greatly improves the mechanical strength of the dissolved oxygen sensor oxygen-sensitive membrane, and prolongs the service life of the dissolved oxygen sensor oxygen-sensitive membrane prepared by loading the fluorescent indicator.

Preferably, the oxygen sensitive membrane is used in a dissolved oxygen sensor and for the detection of dissolved oxygen.

The invention has the beneficial effects that:

the invention discloses a method for preparing a dissolved oxygen sensor oxygen-sensitive membrane by loading a fluorescent indicator and application thereof, wherein the fluorescent indicator is adsorbed and wrapped in a high-transmittance and high-refractive-index nano material in the mixing process of the fluorescent indicator and the nano material, and then the fluorescent indicator is fixed on a transparent supporting layer through polydimethylsiloxane to form a stable fluorescent layer, a refraction layer is introduced to enable the measuring light of the sensor to be fully contacted with a fluorescent substance, the nano material capable of improving the mechanical strength of the dissolved oxygen sensor oxygen-sensitive membrane is used in a shading protective layer, and the impact and damage of the dissolved oxygen sensor oxygen-sensitive membrane in the using process are reduced.

The invention uses mesoporous silica with a radial fold structure to increase the specific surface area of a nano material as much as possible, and then fixes a fluorescence indicator on the surface of the porous material after being processed by protonation, thereby increasing the response speed with oxygen molecules and relieving the loss of the fluorescence indicator in the oxygen-sensitive membrane of the dissolved oxygen sensor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an oxygen-sensitive membrane of a dissolved oxygen sensor prepared by loading a fluorescent indicator according to the present invention;

FIG. 2 is a schematic diagram showing the response of the oxygen-sensitive membrane integrated dissolved oxygen sensor prepared in example 1 of the present invention in air and a saturated sodium sulfite solution;

FIG. 3 shows the case of the oxygen-sensitive membrane prepared in example 1 of the present invention integrated with a dissolved oxygen sensor and operated in an aeration tank of a sewage plant of a certain market for 3 months.

The invention will be further explained with reference to the drawings and the specific embodiments.

As indicated by the reference numbers in fig. 1: 1-shading protective layer, 2-refraction layer, 3-fluorescent layer and 4-transparent support layer.

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.

It should be noted that if directional indications such as up, down, left, right, front, and rear … … are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship, motion, and the like between the components in a specific posture as shown in the drawings, and if the specific posture is changed, the directional indications are changed accordingly. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The technical solutions of the present invention are further described in detail with reference to the following specific examples, which should be understood as merely illustrative and not limitative.

Example 1

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the content of platinum (II) MESO-tetra (pentafluorophenyl) porphine to nano alumina is 1%, the content of nano alumina in the fluorescent layer 3 is 5%, the nano alumina, the platinum (II) MESO-tetra (pentafluorophenyl) porphine, polydimethylsiloxane and n-hexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, fluorescent layer slurry is obtained, then a spin coater is used for uniformly coating the fluorescent layer slurry on the transparent supporting layer 4 of S1, and the coating thickness is 50 μm, so that the fluorescent layer 3 is formed;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 5%, the nano boron nitride, polydimethylsiloxane and normal hexane are mixed and subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 30 micrometers, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the nano silicon carbide in the light-shielding protective layer 1 is 5%, the content of the carbon black in the light-shielding protective layer 1 is 1%, the nano silicon carbide, the carbon black, the polydimethylsiloxane and the n-hexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, light-shielding protective layer slurry is obtained, then a spin coater is used for uniformly coating the light-shielding protective layer slurry on the refraction layer 2 of S3, and the coating thickness is 30 micrometers, so that the light-shielding protective layer 1 is formed.

Example 2

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the content of platinum (II) MESO-tetra (pentafluorophenyl) porphine is 3% of that of nano aluminum oxide, the content of nano aluminum oxide in the fluorescent layer 3 is 3%, the nano aluminum oxide, the platinum (II) MESO-tetra (pentafluorophenyl) porphine, polydimethylsiloxane and n-heptane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, fluorescent layer slurry is obtained, then a spin coater is used for uniformly coating the fluorescent layer slurry on the transparent supporting layer 4 of S1, and the coating thickness is 60 μm, so that the fluorescent layer 3 is formed;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 7%, the nano boron nitride, the polydimethylsiloxane and the n-heptane are mixed and subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 60 μm, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the nano silicon carbide in the light-shielding protective layer 1 is 5%, the content of the carbon black in the light-shielding protective layer 1 is 4%, the nano silicon carbide, the carbon black, the polydimethylsiloxane and the n-heptane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, light-shielding protective layer slurry is obtained, then the light-shielding protective layer slurry is uniformly coated on the refraction layer 2 of S3 by using a spin coater, and the coating thickness is 60 micrometers, so that the light-shielding protective layer 1 is formed.

Example 3

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the content of platinum (II) MESO-tetra (pentafluorophenyl) porphine to nano alumina is 5%, the content of nano alumina in the fluorescent layer 3 is 6%, the nano alumina, the platinum (II) MESO-tetra (pentafluorophenyl) porphine, polydimethylsiloxane and cyclohexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, fluorescent layer slurry is obtained, then a spin coater is used for uniformly coating the fluorescent layer slurry on the transparent supporting layer 4 of S1, and the coating thickness is 15 μm, so that the fluorescent layer 3 is formed;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 10%, the nano boron nitride, polydimethylsiloxane and cyclohexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 15 microns, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the nano silicon carbide in the light-shielding protective layer 1 is 9%, the content of the carbon black in the light-shielding protective layer 1 is 5%, the nano silicon carbide, the carbon black, the polydimethylsiloxane and the cyclohexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, light-shielding protective layer slurry is obtained, then a spin coater is used for uniformly coating the light-shielding protective layer slurry on the refraction layer 2 of S3, and the coating thickness is 15 micrometers, so that the light-shielding protective layer 1 is formed.

Example 4

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the method comprises the following steps of (1) enabling the content of platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots to be 1% of that of mesoporous silica with a radial fold structure to be 3% of that of mesoporous silica with the radial fold structure in a fluorescent layer 3, carrying out ultrasonic treatment on the platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots, the mesoporous silica with the radial fold structure, polydimethylsiloxane and cyclohexane for 30min, stirring for 12h to obtain fluorescent layer slurry, and uniformly coating the fluorescent layer slurry on a transparent supporting layer 4 of S1 by using a spin coater to form the fluorescent layer 3, wherein the coating thickness is 50 microns;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 5%, the nano boron nitride, polydimethylsiloxane and cyclohexane are mixed and then subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 30 micrometers, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the activated carbon fiber composite titanium carbide in the shading protective layer 1 is 5%, the content of the carbon black in the shading protective layer 1 is 1%, the zinc acetate activated carbon fiber composite titanium carbide, the carbon black, polydimethylsiloxane and cyclohexane are subjected to ultrasonic treatment for 30min and then stirred for 12h to obtain shading protective layer slurry, and then the shading protective layer slurry is uniformly coated on the refraction layer 2 of S3 by using a spin coater, wherein the coating thickness is 30 micrometers, so that the shading protective layer 1 is formed.

Example 5

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the content of the platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots to the mesoporous silica with the radial fold structure is 3%, the content of the mesoporous silica with the radial fold structure in the fluorescent layer 3 is 5%, the platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots, the mesoporous silica with the radial fold structure, polydimethylsiloxane and n-heptane are subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, fluorescent layer slurry is obtained, then the fluorescent layer slurry is uniformly coated on the transparent supporting layer 4 of S1 by using a spin coater, and the coating thickness is 60 μm, so that the fluorescent layer 3 is formed;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 7%, the nano boron nitride, the polydimethylsiloxane and the n-heptane are mixed and subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 60 μm, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the activated carbon fiber composite titanium carbide in the shading protective layer 1 is 7%, the content of the carbon black in the shading protective layer 1 is 3%, after the zinc acetate activated carbon fiber composite titanium carbide, the carbon black, polydimethylsiloxane and n-heptane are subjected to ultrasonic treatment for 30min, stirring is carried out for 12h, shading protective layer slurry is obtained, then the shading protective layer slurry is uniformly coated on the refraction layer 2 of S3 by using a spin coater, the coating thickness is 60 micrometers, and the shading protective layer 1 is formed.

Example 6

S1: activation treatment of the transparent support layer 4: activating and treating the transparent supporting layer 4 by using a rotary low-temperature plasma surface treating machine;

s2: preparation of the fluorescent layer 3: the content ratio of the platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots to the mesoporous silica with the radial fold structure is 5%, the content of the mesoporous silica with the radial fold structure in the fluorescent layer 3 is 6%, the platinum (II) MESO-tetra (pentafluorophenyl) porphine quantum dots, the mesoporous silica with the radial fold structure, polydimethylsiloxane and n-hexane are subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, fluorescent layer slurry is obtained, then a spin coater is used for uniformly coating the fluorescent layer slurry on the transparent supporting layer 4 of S1, and the coating thickness is 15 μm, so that the fluorescent layer 3 is formed;

s3: preparation of the refractive layer 2: the content of the nano boron nitride in the refraction layer 2 is 10%, the nano boron nitride, the polydimethylsiloxane and the normal hexane are mixed and subjected to ultrasonic treatment for 30min, then stirring is carried out for 12h, refraction layer slurry is obtained, then the refraction layer slurry is uniformly coated on the fluorescent layer 3 of S2 by using a spin coater, and the coating thickness is 15 microns, so that the refraction layer 2 is formed;

s4: preparing a shading protective layer 1: the content of the activated carbon fiber composite titanium carbide in the shading protective layer 1 is 9%, the content of the carbon black in the shading protective layer 1 is 5%, after the zinc acetate activated carbon fiber composite titanium carbide, the carbon black, polydimethylsiloxane and n-hexane are subjected to ultrasonic treatment for 30min, stirring is carried out for 12h, shading protective layer slurry is obtained, then the shading protective layer slurry is uniformly coated on the refraction layer 2 of S3 by using a spin coater, and the coating thickness is 15 microns, so that the shading protective layer 1 is formed.

The descriptions of the methods for preparing mesoporous silica and activated carbon fiber composite titanium carbide having a radial pleat structure in examples 4 to 6 are provided.

The invention discloses a method for preparing an oxygen sensitive membrane of a dissolved oxygen sensor by loading a fluorescent indicator and application thereof, wherein a preferred scheme is shown as an example 1-3, and the performance of the oxygen sensitive membrane is detected.

The performance index of the oxygen-sensitive film is generally evaluated by using air saturated water or air and saturated sodium sulfite solution, wherein the former two are high values, and the third is a 0-point value; integrating an oxygen sensitive film on a dissolved oxygen sensor, putting the dissolved oxygen sensor into anaerobic water from the air, and judging the response speed of the oxygen sensitive film according to the change of a DO value of the sensor; air to saturated sodium sulfite T90, refers to the response time of integrating an oxygen sensitive membrane on a dissolved oxygen sensor that is put into a saturated sodium sulfite solution from air and does changes from the value in air to below 1 ppm.

Specific detection data are shown in table 1:

TABLE 1

The specific detection diagrams can be shown in fig. 2 and fig. 3, wherein fig. 2 is a schematic diagram of the response of the oxygen-sensitive membrane prepared in example 1 of the present invention when the oxygen-sensitive membrane is integrated on a dissolved oxygen sensor and the membrane is sensitive to air and saturated sodium sulfite solution; FIG. 3 shows the case where the oxygen-sensitive membrane prepared in example 1 of the present invention is integrated with a dissolved oxygen sensor and operated in an aeration tank of a sewage plant of a certain market for 3 months.

Thus, it can be seen that: the oxygen-sensitive membranes prepared in examples 1 to 3 have a fast response speed, and the oxygen-sensitive membranes are integrated in the dissolved oxygen sensor, so that when the oxygen-sensitive membranes are actually applied to aeration tanks of sewage plants, the overall detection data is stable, the oxygen-sensitive membranes are not damaged after three months of use, and the loading condition of the fluorescent indicator is good.

Another preferred embodiment is shown in examples 4-6, which were tested for performance in the same manner as in examples 1-3. Specific detection data are shown in table 2:

TABLE 2

The oxygen-sensitive membranes prepared in examples 4 to 6 had higher response speed, and when the oxygen-sensitive membranes were integrated in a dissolved oxygen sensor and actually used in an aeration tank of a sewage plant, the overall detection data was stable after four months of use, the oxygen-sensitive membranes were not damaged, and the loading condition of the fluorescent indicator was excellent.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.