Graphene / iron oxyhydroxide-doped pressed preparation as well as preparation method and application thereof

Abstract

The invention relates to the field of composite materials, in particular to a graphene / iron oxyhydroxide-doped pressing agent which is composed of graphene, alpha-iron oxyhydroxide and a pressing agent, and the pressing agent is 30 g of PVA 1788, 4 g of AM and 2 mLAA. The preparation method comprises the following steps: step 1, weighing 30 g of PVA1788, 4 g of AM and 2 m of LAA to prepare a pressing agent; and step 2, adding 0.3% of graphene and 0.5% of alpha-iron oxyhydroxide into the pressed preparation in the step 1 to prepare the pressed preparation doped with graphene / iron oxyhydroxide. The graphene / iron oxyhydroxide-doped pressing agent prepared by the invention cooperates with ionic wind to be applied to purification of radioactive aerosol. Experiments show that the synergistic ionic wind assisting effect is very obvious, the pressing effect exceeds 99% after sedimentation is carried out for 5 min, and the pressing effect exceeds 99.9% after sedimentation is carried out for 15 min.

Description

Technical Field

[0001] The invention relates to the field of composite materials, and in particular to a graphene-doped / iron oxyhydroxide pressed preparation and a preparation method and application thereof. Background Art

[0002] Aerosol refers to a stable colloidal system formed by liquid or solid particles with smaller particle sizes dispersed in air. The size of particles is usually described by aerodynamic diameter. The aerodynamic diameter of liquid or solid particles dispersed in an aerosol system is between 1 and 105 nm. Aerosols come from a wide range of sources. Depending on the source, they can be roughly divided into pollution sources caused by human factors and pollution sources caused by natural factors.

[0003] Radioactive aerosol refers to aerosol particles with certain radioactivity or particles contaminated by external radionuclides, making them radioactive. Radioactive aerosol not only has the characteristics of ordinary aerosol, but also has the characteristics of radionuclides, and can enter the human body through eating, breathing and other behaviors to cause further damage. Therefore, efficient purification technology of radioactive aerosol is of great significance to human health.

[0004] There are no reports on the use of graphene / iron oxyhydroxide-doped presses. The currently used radioactive aerosol presses have the following technical problems: the press operation time is long; the current presses are all organic materials, which are expensive and have limitations; and they are accompanied by the generation of a large amount of radioactive waste, resulting in serious secondary pollution problems. Summary of the invention

[0005] In order to comprehensively solve the above problems, the present invention proposes a graphene-doped / iron oxyhydroxide pressed agent and a preparation method and application thereof.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a graphene / iron oxyhydroxide-doped pressing agent, which is composed of: graphene+α-iron oxyhydroxide+pressing agent, wherein the pressing agent is: PVA+AM+AA.

[0007] Preferably, the addition amount of graphene is 3‰, and the addition amount of α-hydroxy iron oxide is 5‰.

[0008] Preferably, the added amounts of PVA, AM and AA are 30 g, 4 g and 2 mL respectively.

[0009] The second aspect of the present invention provides a method for preparing a doped graphene / iron oxyhydroxide pressed agent, comprising:

[0010] Step 1: Weigh 30 g of PVA1788, 4 g of AM and 2 mL of AA to prepare a compression formulation;

[0011] Step 2: Add 3‰ graphene and 5‰ α-hydroxy iron oxide to the pressed preparation of step 1 to prepare a graphene / hydroxy iron oxide-doped pressed preparation.

[0012] A third aspect of the present invention provides a method for purifying radioactive aerosols by using a graphene / iron oxyhydroxide-doped compressed agent in conjunction with ion wind.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The graphene-doped / iron oxyhydroxide-prepared pressed agent prepared by the present invention is highly efficient, and a small amount of the pressed agent can achieve highly efficient suppression of radioactive aerosols.

[0015] 2. The compressed agent of the present invention is simple to operate and has excellent purification effect. The effect is very obvious after ion wind assistance. After 5 minutes of sedimentation, the suppression effect exceeds 99%, and after 15 minutes of sedimentation, the suppression effect exceeds 99.9%.

[0016] 3. The cost of the compressed agent of the present invention is low, lower than the current organic polymer compressed materials.

[0017] 4. The compressed preparation of the present invention has no secondary pollution, produces less radioactive waste after treatment, and is easy to dispose of. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0019] In the attached picture:

[0020] Figure 1 is a flow chart of the method of the present invention;

[0021] Figure 2 It is the natural settling effect of PM5 in the reaction chamber;

[0022] Figure 3 The compression effect of 12g PVA1788+3gAM+3mLAA spraying at different times;

[0023] Figure 4 The compression effect of 24g PVA1788+3gAM+3mLAA spraying at different times;

[0024] Figure 5 The compression effect of 30g PVA1788+4gAM+2mLAA spraying at different times;

[0025] Figure 6 Comparison of compression effects of compressed preparations with different formulations;

[0026] Figure 7 Comparison of the pressing effects after adding different amounts of graphene to the pressing agent;

[0027] Figure 8 Comparison of the compression effects of the compressed preparations after adding different amounts of γ-hydroxyferric oxyhydroxide;

[0028] Fig. 9 Comparison of the compression effects of the compressed preparations after adding different amounts of α-hydroxyferric oxide;

[0029] Fig.10 Comparison of the pressing effects after adding graphene + different amounts of α-hydroxy iron oxide to the pressing agent;

[0030] Fig.11 The long-term pressing effect after adding graphene + α-hydroxy iron oxide to the pressing agent;

[0031] Figure 12 The synergistic effect of ion wind on aerosol deposition: Figure 12 (a) shows the effect of ion wind on aerosol deposition at 1m 3 In the closed cabin, 10.7mg / m 3 The suppression effect of the initial aerosol concentration; Figure 12(b) shows the suppression effect of the initial aerosol concentration at 1m 3 In a closed cabin, 12.5mg / m 3 The suppressive effect of initial aerosol concentration;

[0032] Fig.13 Comparison chart of the suppression effect under various conditions. DETAILED DESCRIPTION

[0033] The following combination Figure 1-Figure 13 The preferred embodiments of the present invention are described. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0034] Embodiment 1:

[0035] A graphene / iron oxyhydroxide-doped pressed agent comprises: graphene+α-iron oxyhydroxide+pressed agent, wherein the pressed agent is: 30g PVA+4g AM+2mL AA.

[0036] The addition amount of graphene is 3‰, and the addition amount of α-hydroxy iron oxide is 5‰.

[0037] Embodiment 2:

[0038] A method for preparing a graphene-doped / iron oxyhydroxide pressed preparation, comprising:

[0039] Step 1: Weigh 30 g of PVA (polyvinyl alcohol 1788) 1788, 4 g of AM (acrylamide) and 2 mL of AA (acrylic acid) to prepare a compression formulation;

[0040] Step 2: Add 3‰ graphene and 5‰ α-iron oxyhydroxide (based on the mass of the pressed preparation) to the pressed preparation of step 1 to prepare a graphene / iron oxyhydroxide-doped pressed preparation.

[0041] Embodiment 3:

[0042] A method for purifying radioactive aerosols by using a graphene / iron oxyhydroxide-doped compressed agent in conjunction with ion wind.

[0043] Among them, the ion wind is generated by an ion wind generator. Youhang negative ion generator and 12V6W duct fan are selected to form an ion wind generator, and the stepless speed regulator is used to control the air volume. Different negative ion air volumes can be adjusted according to needs.

[0044] Table 1 Negative ion generator parameters

[0045]

[0046] experiment:

[0047] Use 1m 3 The environmental chamber and the simulation prototype developed based on the aerosol deposition mechanism were used as the experimental platform. In the closed environmental chamber, wormwood smoke was used as the simulated aerosol, and the initial concentration was controlled at 20-25μg / m 3 , to study the aerosol suppression effect under different application conditions.

[0048] Experimental Results

[0049] 1. Natural Settlement

[0050] Figure 2 As shown in the figure, under natural sedimentation conditions, the sedimentation effect within 80 minutes is very unsatisfactory, and there are phenomena such as condensation between particles, which leads to changes in the particle size of particles. For PM5, within 80 minutes, not only is there no aerosol sedimentation removal effect, but it also leads to an increase in the PM5 concentration in the reaction chamber. After 80 minutes, the particles stabilize and gradually begin to show a natural sedimentation effect. Within 360 minutes, natural sedimentation can remove about 37% of the particles in the reaction chamber.

[0051] (II) Compression effect of compressed preparations with different formulas

[0052] (1) 12g PVA1788+3g AM+3mL AA spraying at different times

[0053] The press preparation was prepared using the formula of 12g PVA1788+3gAM+3mLAA and sprayed in the reaction chamber. Figure 3When spraying for 10min, 20min, and 30min respectively, it can be found that although the suppression effect varies with different spraying time, the suppression effect is significantly improved compared with natural sedimentation. Even if it is only sprayed for 10s, after 300min of sedimentation, the aerosol removal efficiency reaches 73.5%, which is about twice that of natural sedimentation. When the spraying time reaches 20s, the aerosol sedimentation rate can reach 93.8% after 300min. When the spraying time continues to increase, the effect decreases.

[0054] (2) 24g PVA1788+3gAM+3mLAA spraying at different times

[0055] The compression formula was adjusted to 24g PVA1788+3gAM+3mLAA. Figure 4 It can also be seen that there is an obvious suppression effect. The suppression effect of this formula continues to improve with the increase of injection time. When the injection time reaches 30s, the removal efficiency of the aerosol in 360min reaches 92.5%.

[0056] (3) 30g PVA1788+4gAM+2mLAA spraying at different times

[0057] When 30g PVA1788+4gAM+2mLAA was selected as the compression formulation, the compression effect was further improved. Figure 5 Although the suppression effect of the spraying for 10s is not much different from the first two compression formulations, the suppression effect of the aerosol is significantly improved when the spraying time increases. When the spraying time is 30s and 360min, the aerosol sedimentation effect can reach 95.4%.

[0058] (III) Comparison of compression effects of three compressed preparations

[0059] like Figure 6 By comparing the compression effects of the three compressed formulations with a spray time of 30s, it can be found that although the compressed formulations all have good effects, there are still some deviations in the effects after different formulations. In comparison, when 30g PVA1788+4gAM+2mLAA is used as the compressed formulation, the compression effect on the aerosol is the best. Therefore, the subsequent formulation improvement uses the above compressed formulation as the basis.

[0060] (IV) Pressing effect of the press agent after doping with graphene

[0061] like Figure 7, 30g PVA1788+4gAM+2mLAA was used as the basic formula of the compression agent, and graphene was added to the compression agent. When the addition amount was 1‰, 2‰ and 3‰ respectively, the compression effect of the compression agent on aerosols changed differently. It can be seen that when a small amount of graphene is added to the compression agent, it not only does not improve the compression effect on aerosols, but leads to a decrease in the compression effect. However, when the amount of graphene added gradually increases, the compression effect on aerosols has an upward trend. In terms of the amount of graphene added, the order of the aerosol suppression ability is 1‰<2‰<3‰. When the amount of graphene added reaches 3‰, the removal rate of PM5.0 aerosols can reach 98.1% within 300 minutes.

[0062] (V) Changes in the pressing effect after the pressed agent is doped with iron oxyhydroxide

[0063] (1) The pressing effect of the pressed agent after doping with γ-hydroxy iron oxide

[0064] 30g PVA1788+4gAM+2mLAA was used as the basic formula of the compressed preparation, and γ-hydroxy iron oxide was added to the compressed preparation. Figure 8 It can be seen that the addition of γ-hydroxy iron oxide will reduce the removal effect of PM5 in the early stage of sedimentation. Only when the addition of γ-hydroxy iron oxide increases to 3‰, the effect of the later stage of sedimentation will be higher than that of the pure compressed agent without addition. After 360 minutes, the aerosol sedimentation efficiency can reach 97.5%.

[0065] (2) The pressing effect of the pressed agent after doping with α-hydroxy iron oxide

[0066] α-hydroxy iron oxide was used to replace γ-hydroxy iron oxide and added to the basic formula of 30g PVA1788+4gAM+2mLAA compression preparation. Fig. 9 It can be found that compared with γ-hydroxy iron oxide, the effect of α-hydroxy iron oxide on the effect of the compressed agent in the initial stage is significantly weakened, especially when the addition amount is increased to 5‰, the aerosol removal effect in the initial stage of sedimentation is obviously close to that of the pure compressed agent; after 360 minutes, the aerosol removal rate after sedimentation can reach 95.5%.

[0067] Compared with γ-hydroxy iron oxide, α-hydroxy iron oxide has a better effect, so α-hydroxy iron oxide is selected as the additive.

[0068] The addition amount of graphene is 3‰, and the addition amount of α-hydroxy iron oxide is 1‰, 3‰ and 5‰ respectively. Fig.10 It can be seen that after the composite addition, when the addition amount of α-hydroxy iron oxide increases to 3‰ or more based on the addition amount of 3‰ graphene, its aerosol removal effect is better than that of the pure compressed preparation from the beginning.

[0069] After the composite modification of 3‰ graphene + 5‰ α-hydroxy iron oxide, the sedimentation time is higher than 90% at 90min, and at 360min, the suppression effect of aerosol can reach 98.6%.

[0070] (VI) Long-term compression effect of doped post-compression preparations

[0071] The above experimental conditions were tested for a long period of 24 hours. Fig.11 It can be seen that when the sedimentation time reaches 4h, the suppression effect can reach about 99%, when the sedimentation time reaches more than 5h, the suppression effect can reach 99.5%, when the sedimentation time reaches more than 10h, the suppression effect can reach 99.9%. After sedimentation for 24h, the suppression effect is 99.99%.

[0072] (VII) The suppression effect of doped post-pressing agent and ion wind

[0073] After aerosol is generated, ionized wind is blown into the environmental chamber to investigate the removal rate of aerosol under different action times.

[0074] Figure 12 shows the synergistic effect of ion wind on aerosol deposition. 3 In the closed cabin, 10.7mg / m 3 and 12.5 mg / m 3 The suppression effect of the initial aerosol concentration is shown in Figure 12 (a) and (b), respectively. The suppression efficiency reaches 99.5% in about 12 minutes, and there is no rebound phenomenon in 24 hours, which shows that electrocoagulation has a significant effect on enhancing aerosol sedimentation.

[0075] like Fig.13 As shown in the figure, ion wind assistance is performed on the basis of adding 3‰ graphene and 5‰ α-hydroxy iron oxide ratio composite materials to 30g PVA1788+4gAM+2mLAA compression agent. It can be seen that the ion wind assistance effect is very obvious. After 5 minutes of sedimentation, the compression effect has exceeded 99%, and after 15 minutes of sedimentation, the compression effect exceeds 99.9%.

[0076] (VIII) Effect of “Cloud Solvent” on Removal of Cesium

[0077] Cesium nitrate solution was used to simulate the cesium element in the air. Cesium nitrate was dissolved in water and added to the reaction chamber by ultrasonic atomization; an air sampler was used to set the sampling flow rate to 0.5L / min, and the sampling was carried out for 5 minutes to absorb the cesium nitrate salt in the reaction chamber into a 50ml absorption bottle for detection. After the initial state and the composite material with 30g PVA1788+4gAM+2mLAA pressing agent added with 3‰ graphene and 5‰ α-hydroxy iron oxide ratio were pressed for 360 minutes, the concentration of cesium in the absorption liquid before and after pressing was measured to be 1.01×104 and 85.2μg / m3 (with a third-party test report), and the cesium element pressing efficiency for 360 minutes was 99.16%.

[0078] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A graphene-doped / iron oxyhydroxide pressed preparation, characterized in that: The composition is: graphene+α-hydroxy iron oxide+pressing agent, wherein the pressing agent is: PVA+AM+AA.

2. A graphene-doped / iron oxyhydroxide pressed agent according to claim 1, characterized in that: The addition amount of graphene is 3‰, and the addition amount of α-hydroxy iron oxide is 5‰.

3. A graphene-doped / iron oxyhydroxide pressed agent according to claim 2, characterized in that: The added amounts of PVA, AM and AA were 30 g, 4 g and 2 mL, respectively.

4. A method for preparing a graphene-doped / iron oxyhydroxide-doped pressed agent, characterized in that: Step 1: Weigh 30 g of PVA1788, 4 g of AM and 2 mL of AA to prepare a compression formulation; Step 2: Add 3‰ graphene and 5‰ α-hydroxy iron oxide to the pressed preparation of step 1 to prepare a graphene / hydroxy iron oxide-doped pressed preparation.

5. A graphene / iron oxyhydroxide-doped press prepared by the method of claim 4 is used in the purification of radioactive aerosols in coordination with ion wind.

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