A method of degrading polyethylene microplastics

Abstract

The present application relates to a kind of degradation methods of polyethylene microplastics, comprising the following steps: 1) the MP is removed surface moisture;2) the MP of surface moisture removal is placed in deionized water, is treated with ultrasound, and obtain uniform MP suspension;3) the pH of MP suspension is adjusted to 5-8;4) in the suspension of adjusting PH value, PMS solid powder is added, and stirring is until PMS is completely dissolved, and obtain mixture;5) the mixture obtained in step 4) is degraded under the irradiation of VUV lamp reaction.Using the method of the present application, the degradation rate of MP can reach 51.5%, and the toxicity of degradation solution is limited, which can be used as the carbon source for the growth of chlorella.The present application utilizes the synergistic degradation effect of VUV photolysis and sulfate radical-based advanced oxidation system, realizes the efficient degradation of MP under mild conditions, and opens up a new way for designing practical MP pollution remediation technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microplastic treatment in water bodies, and particularly relates to a polyethylene microplastic degradation method. BACKGROUND

[0002] Plastics are widely used in industry, agriculture, medicine and other fields. Global plastic production increased from 1.5 million tons in 1950 to 380 million tons in 2016. As of 2018, global plastic waste reached 6.3 billion tons.

[0003] Microplastics (MPs) are plastic particles with a size of less than 5 mm. They have a large specific surface area and a stable molecular structure, and are easy to become stable carriers of organic pollutants and pathogens. Once MPs enter the human body through the lung or intestinal mucosa, they will accumulate in the body and may cause serious health hazards.

[0004] Existing wastewater treatment processes can remove large plastic particles, but have little effect on MPs. Therefore, more and more research is devoted to the treatment of MPs. Typical MPs treatment methods include physical removal, biological degradation and chemical degradation. Among them, chemical degradation is of great concern because of its speed and completeness. The reported chemical degradation methods include photocatalytic degradation with ZnO nanorod, hydroxyl-rich BiOCl and C, N-doped TiO2 as catalyst, electro-Fenton degradation with TiO2 / graphite cathode, and advanced oxidation degradation with Mn-coated N-doped carbon nanotube activated PMS (PMS). Among them, the SO4 ·- (2.5-3.1V, 30-40μs) AOPs has a significant degradation ability for microplastics. Kang et al. combined PMS with hydrothermal method to activate PMS with Mn-coated N-doped carbon nanotube to degrade MPs, and under high temperature of 140-160℃ and autogenous pressure, the degradation rate of MPs reached 51.5% within 8h. However, there is no report on the efficient degradation of MPs at room temperature and atmospheric pressure by AOPs, which may be because the surface of MPs is hydrophobic, and its adsorption capacity for reactive oxygen species (ROS) in water is weak during degradation. SUMMARY

[0005] Therefore, it is necessary to provide a polyethylene microplastic degradation method to solve the above problems.

[0006] To achieve the above purposes, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a polyethylene microplastic degradation method, comprising the following steps:

[0008] 1) removing the surface moisture of MPs;

[0009] 2) the surface moisture-removed MPs are placed in deionized water and ultrasonic treatment is performed to obtain a uniform MP suspension;

[0010] 3) the pH of the MP suspension is adjusted to 5-8;

[0011] 4) PMS solid powder is added to the suspension after the pH adjustment, and stirring is performed until the PMS is completely dissolved to obtain a mixture;

[0012] 5) the mixture obtained in step 4) is subjected to a degradation reaction under irradiation of a VUV lamp.

[0013] Further, the MPs are dried overnight at 50-70°C and a vacuum degree of 100-133 Pa to remove surface moisture.

[0014] Further, the surface moisture-removed MPs and deionized water have a material-liquid ratio of 0.03-0.125 g:100 mL.

[0015] Further, the ultrasonic treatment time is 50-70 min.

[0016] Further, the pH of the MP suspension is adjusted by an H2SO4 solution and an NaOH solution.

[0017] Further, the concentration of the H2SO4 solution is 0.1 mol / L.

[0018] Further, the concentration of the NaOH solution is 0.1 mol / L.

[0019] Further, the mass ratio of the surface moisture-removed MPs and PMS solid powder is 0.03-0.125:0.49-1.97.

[0020] Further, the control parameter of the VUV lamp in step 5) is 10 W, and the degradation reaction time is 5-48 h.

[0021] The application provides application of the above degradation method in repair of an MPS pollution system.

[0022] The MPS pollution system includes, but is not limited to, solid waste and liquid waste.

[0023] The application has the following advantages and beneficial effects:

[0024] The application provides a chemical degradation method of microplastics in a water body at normal temperature and pressure, and specifically as follows: under normal temperature and pressure, a vacuum ultraviolet activated persulfate salt advanced oxidation system is used to degrade the MPs, and the degradation rate of the MPs can reach 51.5% at most, and the degradation solution has limited toxicity and can be used as a carbon source for the growth of chlorella. The application realizes the efficient degradation of MPs under mild conditions by using the synergistic degradation effect of VUV photolysis and the advanced oxidation system based on sulfate radicals, and opens up a new way for designing a practical MP pollution remediation technology. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Fig. 2 is a graph showing the influence of PMS dosage, pH, MPs concentration and reaction time on the degradation rate of MPs, wherein (a) is the PMS dosage, (b) is the pH, (c) is the MPs concentration, and (d) is the reaction time;

[0026] Figure 2 Fig. 3 is a SEM image of the surface of MPs after different degradation times, wherein a is the SEM image of the surface of the initial MPs, b is the SEM image of the surface of the MPs after 5h of reaction, c is the SEM image of the surface of the MPs after 10h of reaction, and d is the SEM image of the surface of the MPs after 48h of reaction;

[0027] Figure 3 Fig. 4 is a graph showing the influence of the degradation solution on the growth of chlorella, wherein (a) is the influence of the degradation solution at different times on the growth of chlorella, and (b) is a digital photo of chlorella after 10 days of growth with the addition of the degradation solution. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0029] In the following examples, the experimental methods are all conventional methods, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified. The materials, reagents and the like used in the following examples can be obtained from commercial channels, unless otherwise specified.

[0030] Example 1

[0031] The embodiment provides a degradation method of polyethylene microplastics, comprising the following steps:

[0032] 1) The MPs are dried overnight in a vacuum oven at 60 DEG C and a vacuum degree of 120 Pa to remove the water adsorbed on the surface;

[0033] 2) Take 0.1 g of dried MPs and place them in 100 mL of deionized water, and treat them with 40 W ultrasonic waves for 60 min to obtain a uniform MP suspension.

[0034] 3) Adjust the pH of the MP suspension obtained in step 2) to 7 using 0.1 mol / L H2SO4 solution and 0.1 mol / L NaOH solution.

[0035] 4) Add 0.98 g of PMS potassium hydrogen persulfate solid powder to the suspension obtained in step 3) and stir until the PMS is completely dissolved.

[0036] 5) Transfer the mixture obtained in step 4) to an open reaction container with a diameter and height of 15 cm and 2.5 cm, respectively. Install a 10 W VUV lamp above the container.

[0037] 6) Turn on the switch of the lamp to start the degradation process, and turn off the switch to stop the reaction after 48 h of reaction.

[0038] 7) Take out the reacted mixture obtained in step 6) and filter the mixture using a water circulating vacuum pump connected to a filter bottle. The filter membrane has a pore size of 0.22 μm. Store the filtrate in a sealed brown glass bottle and store it in a refrigerator at 4°C. Wash the MP solid powder obtained by filtration repeatedly with distilled water and anhydrous ethanol, and finally dry it in a vacuum oven at 60°C overnight.

[0039] 8) Weigh the MPs obtained in step 7) accurately and calculate the degradation rate of the microplastics by the following formula.

[0040] MPs degradation rate = (W1-W2) / W1 x 100% = (0.1-0.0836) / 0.1 x 100% = 16.4%.

[0041] Wherein, W1 represents the weight of the initial MPs, and W2 represents the weight of the degraded MPs.

[0042] Example 2

[0043] The present embodiment provides a method for degrading polyethylene microplastics, comprising the following steps:

[0044] 1) Dry the MPs in a vacuum oven at 60°C and a vacuum degree of 100 Pa overnight to remove the water adsorbed on the surface.

[0045] 2) Take 0.1 g of dried MPs and place them in 100 mL of deionized water, and treat them with 40 W ultrasonic waves for 60 min to obtain a uniform MP suspension.

[0046] 3) Adjust the pH of the MP suspension obtained in step 2) to 7 with 0.1 mol / L H2SO4solution and 0.1 mol / L NaOH solution.

[0047] 4) Add 0.49 g PMS potassium hydrogen persulfate solid powder to the suspension obtained in step 3) and stir until the PMS is completely dissolved.

[0048] 5) Transfer the mixture obtained in step 4) to an open reaction container with a diameter and height of 15 cm and 2.5 cm, respectively. Install a 10 W VUV lamp above the container.

[0049] 6) Turn on the switch of the lamp to start the degradation process, and turn off the switch to stop the reaction after 48 h of reaction.

[0050] 7) Take out the reacted mixture obtained in step 6) and filter the mixture with a water circulating vacuum pump connected to a filter bottle. The filter membrane has a pore size of 0.22 μm. Store the filtrate in a sealed brown glass bottle and store in a refrigerator at 0°C. Wash the MP solid powder obtained by filtration repeatedly with distilled water and anhydrous ethanol, and finally dry in a vacuum oven at 60°C overnight.

[0051] 8) Weigh the MPs obtained in step 7) accurately and calculate the degradation rate of microplastics by the following formula.

[0052] MPs degradation rate = (W1-W2) / W1 x 100% = (0.1-0.0873) / 0.1 x 100% = 12.7%.

[0053] Wherein, W1 represents the weight of the initial MPs, and W2 represents the weight of the degraded MPs.

[0054] Example 3

[0055] The present embodiment provides a method for degrading polyethylene microplastics, comprising the following steps:

[0056] 1) Dry the MPs in a vacuum oven at 60°C and a vacuum degree of 133 Pa overnight to remove the water adsorbed on the surface.

[0057] 2) Weigh 0.1 g of dried MPs and place them in 100 mL of deionized water, and ultrasonically treat for 60 min at 40 W to obtain a uniform MP suspension.

[0058] 3) Adjust the pH of the MP suspension obtained in step 2) to 7 with 0.1 mol / L H2SO4solution and 0.1 mol / L NaOH solution.

[0059] 4) Add 1.97 g PMS potassium hydrogen persulfate solid powder to the suspension obtained in step 3), stir until PMS is completely dissolved.

[0060] 5) Transfer the mixture obtained in step 4) to an open reaction vessel with a diameter and height of 15 cm and 2.5 cm, respectively. Install a 10W VUV lamp above the vessel.

[0061] 6) Turn on the switch of the lamp to start the degradation process, and turn off the switch to stop the reaction after 48h of reaction.

[0062] 7) Take out the reacted mixture obtained in step 6), and filter the mixture with a water circulating vacuum pump connected to a filter bottle. The pore size of the filter membrane is 0.22 μm. Store the filtrate in a sealed brown glass bottle and store in a refrigerator at 4°C. The MP solid powder obtained by filtration is repeatedly washed with distilled water and anhydrous ethanol, and finally dried in a vacuum oven at 60°C overnight.

[0063] 8) Accurately weigh the MPs obtained in step 7) and calculate the degradation rate of microplastics by the following formula.

[0064] The degradation rate of MPs = (W1-W2) / W1x100% = (0.1-0.0836) / 0.1x100% = 16.2%.

[0065] Wherein, W1 represents the weight of the initial MPs, and W2 represents the weight of the degraded MPs.

[0066] Example 4:

[0067] The present embodiment provides a method for degrading polyethylene microplastics, comprising the following steps:

[0068] 1) Dry the MPs in a vacuum oven at 50°C and a vacuum degree of 120 Pa overnight to remove the water adsorbed on the surface.

[0069] 2) Weigh 0.03 g of dried MPs and place them in 100 mL of deionized water, and treat with 40W ultrasonic for 60 min to obtain a uniform MP suspension.

[0070] 3) Adjust the pH of the MP suspension obtained in step 2) to 5 with 0.1 mol / L H2SO4 solution and 0.1 mol / L NaOH solution.

[0071] 4) Add 1.97 g PMS potassium hydrogen persulfate solid powder to the suspension obtained in step 3), stir until PMS is completely dissolved.

[0072] 5) The mixture obtained in step 4) is transferred to an open reaction vessel with a diameter and height of 15 cm and 2.5 cm, respectively. A 10 W VUV lamp is installed above the vessel.

[0073] 6) The switch of the lamp is turned on to start the degradation process, and after 5 h of reaction, the switch is turned off to stop the reaction.

[0074] 7) The reacted mixture obtained in step 6) is taken out and filtered using a water-circulating vacuum pump connected to a filter flask. The filter membrane has a pore size of 0.22 μm. The filtrate is stored in a sealed brown glass bottle and kept in a refrigerator at 4°C. The MP solid powder obtained by filtration is repeatedly washed with distilled water and anhydrous ethanol, and finally dried in a vacuum oven at 60°C overnight.

[0075] 8) The MPs obtained in step 7) are accurately weighed, and the degradation rate of microplastics is calculated by the following formula.

[0076] The degradation rate of MPs = (W1-W2) / W1 x 100% = (0.00237) / 0.03 x 100% = 7.9%.

[0077] wherein W1 represents the weight of the initial MPs, and W2 represents the weight of the degraded MPs.

[0078] Example 5:

[0079] The present embodiment provides a method for degrading polyethylene microplastics, comprising the following steps:

[0080] 1) The MPs are dried in a vacuum oven at 70°C and a vacuum degree of 120 Pa overnight to remove the water adsorbed on the surface.

[0081] 2) 0.125 g of dried MPs are weighed and placed in 100 mL of deionized water, and ultrasonicated at 40 W for 60 min to obtain a uniform MP suspension.

[0082] 3) The pH of the MP suspension obtained in step 2) is adjusted to 8 using 0.1 mol / L H2SO4 solution and 0.1 mol / L NaOH solution.

[0083] 4) 1.97 g of PMS potassium peroxymonosulfate solid powder is added to the suspension obtained in step 3) and stirred until the PMS is completely dissolved.

[0084] 5) The mixture obtained in step 4) is transferred to an open reaction vessel with a diameter and height of 15 cm and 2.5 cm, respectively. A 10 W VUV lamp is installed above the vessel.

[0085] 6) The switch of the lamp is turned on to start the degradation process, and after 10 h of reaction, the switch is turned off to stop the reaction.

[0086] 7) The reacted mixture obtained in step 6) was taken out and filtered using a water circulating vacuum pump to connect a filter bottle. The filter membrane had a pore size of 0.22 pm. The filtrate was stored in a sealed brown glass bottle and kept in a refrigerator at 4°C. The MP solid powder obtained by filtration was repeatedly washed with distilled water and anhydrous ethanol, and finally dried in a vacuum oven at 60°C overnight.

[0087] 8) The MP obtained in step 7) was accurately weighed and the degradation rate of the microplastics was calculated by the following formula.

[0088] The degradation rate of the MP = (W1-W2) / W1 x 100% = (0.0141) / 0.125 x 100% = 11.28%.

[0089] Wherein, W1 represents the weight of the initial MP, and W2 represents the weight of the MP after degradation.

[0090] Example 6

[0091] This example investigated the effects of the PMS dosage (0.0613, 0.4908, 0.9816, 1.4724, 1.9632) g, the initial pH value (2, 5, 7, 8, 9, 11), the initial MP concentration (0.3, 0.5, 0.75, 1, 1.25, 1.5) g / L, and the reaction time (5, 10, 24, 36, 48) on the degradation performance of polyethylene microplastics, including the following steps:

[0092] 1) The MP was dried in a vacuum oven at 60°C and a vacuum degree of 120 Pa overnight to remove the water adsorbed on the surface.

[0093] 2) 0.03-0.15 g of the dried MP was weighed and placed in 100 mL of deionized water, and ultrasonic treatment was performed for 60 min to obtain a uniform MP suspension.

[0094] 3) The pH of the MP suspension obtained in step 2) was adjusted to 2-11 using a 0.1 mol / L H2SO4 solution and a 0.1 mol / L NaOH solution.

[0095] 4) 0.0613-1.9632 g of PMS solid powder was added to the suspension obtained in step 3) and stirred until the PMS was completely dissolved.

[0096] 5) The mixture obtained in step 4) was transferred to an open reaction container with a diameter and height of 15 cm and 2.5 cm, respectively. A 10W VUV lamp was installed above the container.

[0097] 6) Turn on the light switch to start the degradation process, and turn off the switch to stop the reaction after 5-48h.

[0098] 7) Take out the reaction mixture obtained in step 6) and filter the mixture using a water circulating vacuum pump connected to a filter bottle. The filter membrane has a pore size of 0.22 μm. Store the filtrate in a sealed brown glass bottle and keep it in a refrigerator at 4°C. The MP solid powder obtained by filtration is repeatedly washed with distilled water and anhydrous ethanol, and finally dried in a vacuum oven at 60°C overnight.

[0099] 8) Accurately weigh the MPs obtained in step 7) and calculate the degradation rate of microplastics by the following formula.

[0100] MPs degradation rate = (W1-W2) / W1 x 100%

[0101] Where W1 represents the weight of the initial MPs, and W2 represents the weight of the degraded MPs. The experimental results are shown in Figure 1 Figure 1 a shows that with the increase of PMS dosage, the degradation rate of MPs first increases and then stabilizes. When the dosage of PMS increases from 0.0613 g to 0.9816 g, the degradation rate of MPs increases from 7.1% to 16.4%. Figure 1 b shows that with the increase of pH, the degradation rate of MPs first increases and then decreases, and the performance is best when pH = 7. Figure 1 c shows that with the increase of MPs concentration, the degradation rate of MPs shows a downward trend. When the initial concentration of MPs increases from 0.3 g / L to 1.5 g / L, the weight loss rate of MPs decreases from 21.1% to 8.9%. With the extension of reaction time, the degradation rate of MPs continues to increase, reaching 51.5% at 48h Figure 1 d).

[0102] Comparative Example 1

[0103] This comparative example provides a degradation method for polyethylene microplastics. The difference between this comparative example and Example 1 is only that in step 5), a 10W UV lamp is installed above the open reaction container, and the rest is the same as Example 1.

[0104] Accurately weigh the MPs obtained in this comparative example and calculate the degradation rate of microplastics = (0.1-0.09778) / 0.1 x 100% = 2.22%.

[0105] Comparative Example 2

[0106] ​This comparative example provides a degradation method of polyethylene microplastics. The difference between this comparative example and Example 1 is only that in step 4), 0.01 g of PMS solid powder is added to the suspension obtained in step 3) and stirred until the PMS is completely dissolved. The rest is the same as Example 1.

[0107] The MPs obtained in this comparative example were accurately weighed and calculated the degradation rate of microplastics = (0.1-0.0932) / 0.1x100% = 6.8%. When the dosage of PMS is too low, the number of active oxygen species such as SO4·-and HO· produced by the system is limited, which is not enough to efficiently degrade MPs.

[0108] Example Experimental Example 1

[0109] The mixture prepared according to steps 1)-4) of Example 1 was respectively transferred to an open reaction container with a diameter and height of 15 cm and 2.5 cm, and a 10W VUV lamp was installed above the container of Example 1. Turn on the switch of the lamp to start the degradation process, and at the 5th, 10th, 24th, 36th, and 48th hours of the reaction, respectively, a portion of the mixture was taken out and filtered using a water circulating vacuum pump connected to a filter bottle. The pore size of the filter membrane is 0.22μm. The five MP filtrates were respectively stored in sealed brown glass bottles and stored in a refrigerator at 4℃.

[0110] The MPs obtained in step 1) of Example 1 and the MP solid powder obtained by filtering the mixture taken out at the 5th, 10th, and 48th hours of the reaction were repeatedly washed with distilled water and anhydrous ethanol, and finally dried in a vacuum oven at 60℃ overnight. The SEM image of the surface of the obtained MPs is shown in Figure 2 As can be seen, with the extension of the degradation time, the roughness of the surface of the MPs is continuously increased, and the cracks are more and more obvious, as indicated by the arrow area.

[0111] The three MP filtrates obtained at the 5th, 10th, and 48th hours of the reaction and deionized water (0.5mL) were respectively added to 50mL of Chlorella growth solution (BG11) to obtain four culture solutions. The initial pH of the culture solution was adjusted to 7.5 with 0.1mol / L H2SO4 and 0.1mol / L NaOH. Chlorella was cultured under continuous illumination of 8000Lux white fluorescent lamp at a rotation speed of 100rpm, and the light-dark ratio was 12:12. The experiment was carried out in a constant temperature and humidity incubator, the temperature was 25℃, and the humidity was 70%. The optical density of the sample at 680nm was measured every 24h with a UV-visible spectrophotometer as shown in Figure 3 a.

[0112] The growth of Chlorella with 0.5 mL 48h MPs degradation solution was generally comparable to the control group with 0.5 mL deionized water, specifically, the ratio of optical density on the tenth day to the initial optical density of Chlorella with 48h MPs degradation solution was 6.87, while the ratio of optical density to the initial optical density of the control group with deionized water was 6.6, indicating that MPs degradation solution promoted the growth of Chlorella and could be used as a carbon source for Chlorella growth. Figure 3 b shows that Chlorella grew well after adding 48h MPs degradation solution, indicating that the degradation method is green and non-toxic, and the toxicity of the degradation solution produced is very low.

[0113] Vacuum ultraviolet (VUV) is a short-wave ultraviolet light with a wavelength less than 200 nm. At the same power, the photon energy of VUV lamp is higher than that of UV lamp (VUV-185 nm is 6.7 eV, and UV-254 nm is 4.88 eV). In addition, VUV can induce water ionization to generate HO·, without the need for additional chemical reagents (equations 1-2). Therefore, VUV-activated PMS can simultaneously promote the generation of HO· and SO4 ·- , thereby accelerating the degradation of target pollutants.

[0114] H2O + VUV→ x＝185nm HO· + H· Φ = 0.33 (1)

[0115] H2O + VUV→ x＝185nm HO· + H + + eaq - Φ e = 0.045 (2)

[0116] VUV photolysis technology has strong oxidizing ability under mild conditions, because VUV photons can directly break most stable chemical bonds. Based on this, we believe that the VUV-activated PMS system can efficiently degrade MPs under mild conditions, because VUV not only can oxidize the surface of MPs to improve the adsorption of ROS on its surface, but also can effectively activate PMS to generate a large amount of ROS. MPs can be effectively chemically degraded even under mild conditions.

[0117] The above-described embodiments only express several embodiments of the present application, which are described in detail and specifically, but should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of degrading polyethylene microplastics, characterized in that, The method comprises the following steps: 1) removing surface moisture of MPs; 2) placing the MPs with removed surface moisture in deionized water and ultrasonic treating to obtain a uniform MP suspension; the ratio of the MPs with removed surface moisture to the deionized water is 0.03-0.125 g:100 mL; 3) adjusting the pH of the MP suspension to 5-8; 4) adding PMS solid powder to the MP suspension with adjusted pH and stirring until the PMS is completely dissolved to obtain a mixture; 5) performing a degradation reaction on the mixture obtained in step 4) under irradiation of a VUV lamp.

2. The method of claim 1, wherein the polyethylene microplastics are degraded by the method. The MPs are dried overnight at 50-70℃ and a vacuum degree of 100-133 Pa to remove surface moisture.

3. The method of claim 1, wherein the polyethylene microplastics are degraded by the method. The ultrasonic treating time is 50-70 min.

4. The method of claim 1, wherein the polyethylene microplastics are degraded by the method. The pH of the MP suspension is adjusted by H2SO4 solution and NaOH solution.

5. The method of claim 4, wherein the polyethylene microplastics are degraded by the action of the enzyme. The concentration of the H2SO4 solution is 0.1 mol / L.

6. The method of claim 4, wherein the polyethylene microplastics are degraded by the action of the bacteria. The concentration of the NaOH solution is 0.1 mol / L.

7. The method of claim 1, wherein the polyethylene microplastics are degraded by the method. The mass ratio of the MPs with removed surface moisture to the PMS solid powder is 0.03-0.125:0.49-1.

97.

8. The method of claim 1, wherein the polyethylene microplastics are degraded. The control parameter of the VUV lamp in step 5) is 10 W, and the degradation reaction time is 5-48 h.

9. Application of the degradation method according to any one of claims 1-8 to remediation of an MPS contaminated system.

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