Anti-fouling and anti-blocking filter capable of efficiently adsorbing high-risk pollutants in water and operation method

Abstract

The invention discloses an anti-fouling filter capable of efficiently adsorbing high-risk pollutants in water and an operation method. The filter comprises a shell, and a manta ray bionic filtering structure, an inner support, a filtering adsorption layer and an outer support which are sequentially arranged in the shell from inside to outside, the shell is provided with a water inlet communicated with the upper end of the manta ray bionic filtering structure, a water outlet communicated with the filtering adsorption layer and a sewage draining exit communicated with the lower end of the manta ray bionic filtering structure, and the sewage draining exit is provided with a sewage draining valve. The pollution and blockage of solid particles to the internal filter layer can be effectively reduced, and the efficiency and the cost are highly matched.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a filter and an operating method thereof that is resistant to fouling and clogging and can efficiently absorb high-risk pollutants in water. Background Art

[0002] There are many types of high-risk pollutants in water, including perfluoroalkyl compounds (PFAS), a class of synthetic persistent organic pollutants. Their structure contains high-energy C—F bonds, which exhibit extremely high stability. PFAS are widely distributed in nature and can enter wastewater directly through leachate, dust, and other sources, leading to varying levels of PFAS detection in sewage treatment plants. PFAS are bioaccumulative, accumulating and amplifying within organisms. Long-term exposure to PFAS may damage the human reproductive and endocrine systems, increasing the risk of disease.

[0003] The use of activated carbon can effectively adsorb high-risk pollutants in water and provide good water quality for subsequent deep treatment. However, the tiny particles in the water can easily cause the filter element to clog and also cause the activated carbon adsorption performance to be lost. Therefore, a new type of filter is needed to efficiently adsorb high-risk pollutants in water to solve the above problems. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a filter and an operating method for efficiently absorbing high-risk pollutants in water that are resistant to fouling and clogging.

[0005] The technical solution of the present invention is: a filter that is resistant to fouling and clogging and can efficiently absorb high-risk pollutants in water. The filter includes a shell, and a manta ray bionic filtration structure, an inner support, a filtration adsorption layer, and an outer support arranged in the shell from the inside to the outside; the shell is provided with a water inlet connected to the upper end of the manta ray bionic filtration structure, a water outlet connected to the filtration adsorption layer, and a sewage outlet connected to the lower end of the manta ray bionic filtration structure. The sewage outlet has a sewage valve, and a buckle is provided at the bottom of the shell for fixing the filtration adsorption layer. An inner cover is provided inside to form a buckle with the circular outer shell at the upper end of the manta ray bionic filtration structure to fix the manta ray bionic filtration structure. At the same time, the contaminated PP cotton and activated carbon can be replaced, thereby improving the efficiency of filter element replacement.

[0006] Furthermore, the manta ray bionic filtering structure is composed of a plurality of filter discs stacked at intervals, and each filter disc is connected and fixed by a plurality of support rods.

[0007] The filter disc is annular in structure, and is bent downward and is divided into a first filter surface, a second filter surface, and a third filter surface from the inside to the outside through two bends.

[0008] Description: Based on the characteristics of large particles in the water, the manta ray bionic filtration structure uses fish gill scales to screen and effectively intercept large particles in the incoming water, thereby reducing the load of the subsequent filtration adsorption layer, reducing filter clogging, and improving the removal effect of PFAS.

[0009] Furthermore, the angle between the first filter surface and the support rod is 20-25°, the angle between the second filter surface and the vertical direction is 40-45°, and the angle between the third filter surface and the vertical direction is 30-35°. Specifically, the outer diameter of the filter disc is 20mm, the inner diameter of the filter disc is 14mm, and the filter discs are stacked at intervals of 7.0-7.5mm. A total of four support rods are circumferentially arranged on the inner annular surface of the filter disc and connected to the internal base and inner cover of the filter column housing to maintain structural stability.

[0010] Note: By optimizing the filter disc of the manta ray bionic filtration structure, the bionic scale stack constructed within the above range can further enhance the interception of large particles in the incoming water, reduce the load of the subsequent filtration adsorption layer, further prevent the filter from clogging, and improve the removal effect of PFAS.

[0011] Furthermore, the filter disc is circumferentially provided with a plurality of radially arranged micro grooves.

[0012] Description: Through the setting of fish gill scale stacking screening combined with micro groove turbulence, based on the Chuangya aperture gradient interception technology, synchronous pre-screening and scale prevention are achieved, and the load of subsequent filtration and screening is enhanced and reduced.

[0013] Furthermore, the filtration and adsorption layer is composed of a PP cotton filtration layer and an activated carbon adsorption layer, the PP cotton filtration layer is PP cotton, and the activated carbon adsorption layer is activated carbon of three different mesh sizes, and the distribution of the PP cotton filtration layer and the activated carbon adsorption layer is: from inside to outside, it is composed of PP cotton, 60 mesh activated carbon, PP cotton, 100 mesh activated carbon, PP cotton, 200 mesh activated carbon and PP cotton.

[0014] Note: By placing PP cotton between each activated carbon layer, the innermost layer of PP cotton can be used to filter some unseparated solid particles in the water, thereby protecting the internal adsorption layer. The filtration accuracy of the outermost layer of PP cotton is 1-5μm, which can further intercept small-size particles and prevent the activated carbon from running. When the filter adsorption layer of the filter needs to be replaced, the filter can be taken out, the upper cover of the outer shell can be unscrewed, the filter layer and the adsorption layer of the filter adsorption layer can be taken out as a whole, cleaned and put back for continued use.

[0015] Furthermore, the 60-mesh activated carbon and the 100-mesh activated carbon are both ordinary activated carbon, and the 200-mesh activated carbon is modified activated carbon.

[0016] Note: The adsorption layer uses a combination of ordinary activated carbon and modified activated carbon. The ordinary activated carbon in the inner layer adsorbs long-chain PFASs, and the remaining short-chain PFASs are adsorbed by the modified activated carbon, which can maximize the utilization rate of the modified activated carbon with high adsorption performance.

[0017] Furthermore, the modified activated carbon is limited water modified activated carbon or composite activated modified activated carbon.

[0018] Description: Limited water modified activated carbon has a new type of hydrophilic adsorption effect, which combined with the hydrophobic adsorption effect of ordinary activated carbon can maximize the rapid and efficient removal of high-risk pollutants.

[0019] Furthermore, the preparation method of the composite activated modified activated carbon is:

[0020] 1) Wood-based activated carbon (particle size 2-3 mm) that has been washed and impurities removed with water is placed in a reactor, a mixture of Ar and H2 is introduced, and a dielectric barrier discharge plasma is used for treatment for 30-45 minutes to obtain pretreated activated carbon. The power of the dielectric barrier discharge plasma is periodically varied within a range of 400-600 W at a frequency of 20-50 W / 5 minutes.

[0021] 2) The pre-treated activated carbon and water are placed in a supercritical state of water at a mass ratio of 1:8-12 for 20-40 minutes, and during the treatment, 1-3 m 3 / h to add O2 for 5 to 10 minutes, and then add O3 at a rate of 0.5 to 1 m 3 O3 was added at a flow rate of / h until the treatment was completed, and then cooled to room temperature to obtain composite activated modified activated carbon;

[0022] The volume ratio of Ar to H2 in the mixed gas is (8-9): (2-1), and the supercritical state of water is at a temperature of 374-420°C and a pressure of 22.1-28 MPa.

[0023] Description: By pretreating activated carbon with periodic changes in dielectric barrier discharge plasma, a gradient pore structure can be constructed on the carbon surface, so that the ratio of micropores to mesopores is about 3:1. By using oxygen and ozone alternately as auxiliary modifiers and combining the pretreatment of activated carbon with water under the supercritical state, modified activated carbon with better adsorption performance can be obtained. Using it as the third layer of modified activated carbon can further improve the adsorption effect of PFASs.

[0024] The present invention also provides a method for operating a filter that is resistant to fouling and clogging and can efficiently absorb high-risk pollutants in water, comprising the following steps:

[0025] S1. Connect the water pipe to the water inlet of the filter so that the water pipe and the water outlet are in a connected state, and close the drain valve so that the drain outlet and the water inlet are in a closed state;

[0026] S2. Water is injected through the water inlet. The water flows along the main channel in the middle of the manta ray bionic filtration structure and through the gaps in the multi-layer separation structure formed between the filter discs to the filtration and adsorption layer. Under the action of water pressure, the water passes through the filtration and adsorption layer to complete the separation of particles in the incoming water, pre-filtration, adsorption, and post-filtration. Finally, the purified water is discharged through the water outlet.

[0027] S3. When the filter adsorption layer is contaminated, the drain valve is opened to open the drain outlet. Water is injected along the water inlet, passes through the main channel of the manta ray bionic filter structure and the gaps in the multi-layer separation structure, and flows out of the drain outlet from the lower end of the filter. This completes the flushing of particles attached to the filter adsorption layer in the filter and the discharge of separated particles, thus completing the filter drainage.

[0028] The beneficial effects of the present invention are:

[0029] (1) The filter of the present invention, which is resistant to fouling and can efficiently adsorb high-risk pollutants in water, is designed with a manta ray bionic filtration structure + four-layer filtration + three-layer adsorption, which can effectively reduce the fouling of the internal filter layer by solid particles, achieving a high degree of fit between efficiency and cost; it can effectively remove toxic and harmful substances such as tiny particles and perfluorinated compounds in water, and can meet the adsorption and purification needs of tap water.

[0030] (2) The anti-fouling and high-efficiency adsorption filter of the present invention for high-risk pollutants in water has low use cost, and the filter layer and adsorption layer of the filter adsorption layer can be replaced, thereby reducing the use cost. At the same time, the filter adsorption layer of the filter of the present invention has a long service life. During daily use, due to the setting of the manta ray bionic filter structure, the inner layer of PP cotton is less polluted than the traditional filter.

[0031] (3) The anti-fouling and high-efficiency adsorption filter of the present invention for high-risk pollutants in water can separate tiny particles into solid and liquid through its structural design, thereby reducing the fouling and clogging of the filter layer and the adsorption layer of the filter adsorption layer, and extending the service life of the filter layer and the adsorption layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is an appearance diagram of the filter of the present invention;

[0033] Figure 2 Schematic diagram of the internal structure of the filter of the present invention;

[0034] Figure 3 is a side sectional view of the filter of the present invention;

[0035] Figure 4Schematic diagram of the manta ray bionic filtering structure of the filter of the present invention;

[0036] Figure 5 This is a schematic diagram of the assembly structure of the filter sheet and support rod of the manta ray bionic filtering structure of the present invention;

[0037] Figure 6 Schematic diagram of the angle between the filter sheet and the support rod of the manta ray bionic filtering structure of the present invention;

[0038] Figure 7 is a filtration efficiency graph of the filter experiment of the present invention;

[0039] Figure 8 is a graph of PFAS removal rates from the filter experiment of the present invention;

[0040] Among them, 1-shell, 11-water inlet, 12-water outlet, 13-sewage outlet, 2-manta ray bionic filtration structure, 21-filter plate, 211-first filter surface, 212-second filter surface, 213-third filter surface, 214-micro groove, 22-support rod, 3-inner support, 4-filter adsorption layer, 41-PP cotton filter layer, 42-activated carbon adsorption layer, 5-outer support. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with specific implementation methods to better demonstrate the advantages of the present invention.

[0042] Example 1: Figure 1-Figure 3 As shown, a filter that is anti-fouling and highly efficient in absorbing high-risk pollutants in water comprises a shell 1, and a manta ray bionic filter structure 2, an inner support 3, a filter adsorption layer 4 and an outer support 5, which are sequentially arranged in the shell 1 from the inside to the outside; the shell 1 is made of hard plastic, and the shell 1 is provided with an upper cover detachably connected by a buckle, the shell 1 is provided with a water inlet 11 connected to the upper end of the manta ray bionic filter structure 2, a water outlet 12 connected to the filter adsorption layer 4 and a sewage outlet 13 connected to the lower end of the manta ray bionic filter structure 2, the sewage outlet 13 has a sewage valve, a buckle is provided at the bottom of the shell 1 for fixing the filter adsorption layer 4, and an inner cover is provided inside to form a buckle with the circular outer shell at the upper end of the manta ray bionic filter structure 2 to fix the manta ray bionic filter structure 2, and the contaminated PP cotton and activated carbon can be replaced, thereby improving the efficiency of filter element replacement;

[0043] About manta ray bionic filtration structure 2: Figure 4-Figure 6As shown, the manta ray bionic filtering structure 2 is composed of a number of filter discs 21 stacked at intervals, and each filter disc 21 is connected and fixed by a number of support rods 22. The filter disc 21 is an annular structure, and the filter disc 21 is bent downward and is divided into a first filter surface 211, a second filter surface 212, and a third filter surface 213 from the inside to the outside through two bends; the angle between the first filter surface 211 and the support rod 22 is 25°, the angle between the second filter surface 212 and the vertical direction is 45°, and the angle between the third filter surface 213 and the vertical direction is 35°. Specifically, the outer ring diameter of the filter disc is 20mm, the inner ring diameter of the filter disc is 14mm, and the filter discs are stacked at intervals of 7.5mm. There are four support rods in total, which are circumferentially arranged on the inner annular surface of the filter disc and connected to the internal base and inner cover of the filter column shell to maintain structural stability. A number of radially arranged micro grooves 214 are circumferentially arranged on the filter disc 21;

[0044] About the filter adsorption layer 4: Figure 3 As shown, the filtration adsorption layer 4 is composed of a PP cotton filtration layer 41 and an activated carbon adsorption layer 42, the PP cotton filtration layer 41 is PP cotton, and the activated carbon adsorption layer 42 is three types of activated carbon with different mesh sizes. Specifically, the three types of activated carbon with different mesh sizes are 60 mesh activated carbon, 100 mesh activated carbon, and 200 mesh activated carbon, and the distribution of the PP cotton filtration layer 41 and the activated carbon adsorption layer 42 is as follows: from the inside to the outside, they are composed of PP cotton, 60 mesh activated carbon, PP cotton, 100 mesh activated carbon, PP cotton, 200 mesh activated carbon and PP cotton, wherein the 60 mesh activated carbon and 100 mesh activated carbon are both ordinary activated carbon, and the 200 mesh activated carbon is modified activated carbon, and the modified activated carbon is limited water modified activated carbon. The filtration accuracy of the PP cotton is 1 to 5 μm.

[0045] Among them, ordinary activated carbon refers to commercially available activated carbon, and confined water modified activated carbon refers to activated carbon modified by confined water enhancement technology. This technology can improve the adsorption efficiency of traditional adsorption materials for high-risk pollutants in a reagent-free and low-cost manner, providing an effective solution for the efficient removal of high-risk pollutants in water. Confined water activated carbon belongs to the existing technology, see [Shi, Y., Mu, H., You, J., Han, C., Cheng H., Wang, J., Hu, H., Ren, H. 2023. Confined water–encapsulated activated carbon for capturing short-chain perfluoroalkyl and polyfluoroalkyl substances from drinking water. PNAS, 120(27), e2219179120; Sun Y, Yu F, Li C, et. Nanomicro-confined water in graphenehydrogel as super adsorbents for water purification[J]. Nano-Micro Letters, 2019, 12(1): 2.]

[0046] Example 2: This example provides a method for operating a filter that efficiently absorbs high-risk pollutants in water using the anti-fouling and anti-clogging method of Example 1, comprising the following steps:

[0047] S1. Connect the water pipe to the water inlet 11 of the filter, so that the water pipe and the water outlet 12 are in a connected state, and close the sewage valve so that the sewage outlet 13 and the water inlet 11 are in a closed state;

[0048] S2. Water is injected through the water inlet 11. The water flows along the main channel in the middle of the manta ray bionic filter structure 2 and through the gaps in the multi-layer separation structure formed between the filter discs 21 to the filter adsorption layer 4. Under the action of water pressure, the water passes through the filter adsorption layer 4 to complete the particle separation, pre-filtration, adsorption and post-filtration of the incoming water, and finally the purified water is discharged through the water outlet 12.

[0049] S3. When the filter adsorption layer 4 is contaminated, the drain valve is opened to open the drain outlet 13. Water is injected along the water inlet 11, passes through the main channel of the manta ray bionic filter structure 2 and the gap of the multi-layer separation structure, and flows out of the drain outlet 13 from the lower end of the filter, so that the accumulated tiny particles flow out with the water flow, thereby completing the flushing of the particles attached to the inner layer of the PP cotton filter layer of the filter adsorption layer 4 in the filter and the discharge of the separated particles, completing the filter drainage; when the filter adsorption layer 4 of the filter needs to be replaced, the filter can be taken out, the upper cover of the outer shell can be unscrewed, the filter layer and adsorption layer of the filter adsorption layer 4 can be taken out as a whole, washed and put back for continued use.

[0050] Example 3: This example differs from Example 1 in that the structure of the filter disc of the manta ray bionic filtering structure 2 is different. Specifically, the angle between the first filter surface 211 and the support rod 22 is 23°, the angle between the second filter surface 212 and the vertical direction is 43°, and the angle between the third filter surface 213 and the vertical direction is 33°.

[0051] Example 4: This example differs from Example 1 in that the structure of the filter disc of the manta ray bionic filtering structure 2 is different. Specifically, the angle between the first filter surface 211 and the support rod 22 is 20°, the angle between the second filter surface 212 and the vertical direction is 40°, and the angle between the third filter surface 213 and the vertical direction is 30°.

[0052] Example 5: This example differs from Example 1 in that the spacing between the filter discs of the manta ray bionic filtering structure 2 is different. Specifically, the filter discs are stacked at intervals of 7.0 mm.

[0053] Example 6: This example differs from Example 3 in that the modified activated carbon is composite activated modified activated carbon, and the preparation method of the composite activated modified activated carbon is:

[0054] 1) Wood-based activated carbon (particle size 2-3 mm) that has been washed and impurities removed with water is placed in a reactor, a mixture of Ar and H2 is introduced, and a dielectric barrier discharge plasma is used for 40 minutes to obtain pretreated activated carbon. The power of the dielectric barrier discharge plasma is periodically varied within a range of 400-600 W at a frequency of 45 W / 5 minutes.

[0055] 2) The pre-treated activated carbon and water were placed in a supercritical state of water at a mass ratio of 1:10 for 35 minutes. During the treatment, 2m 3 O2 was added at a flow rate of 0.8 m / h for 8 min, followed by O3 3 O3 was added at a flow rate of / h until the treatment was completed, and then cooled to room temperature to obtain composite activated modified activated carbon;

[0056] The volume ratio of Ar to H2 in the mixed gas is 8.5:1.5, and the supercritical state of water is at a temperature of 405°C and a pressure of 25 MPa.

[0057] Example 7: The difference between this example and Example 6 is that the pretreatment of the composite activated modified activated carbon is different. Specifically, the wood-based activated carbon that has been washed and removed of impurities with water is placed in a reactor, and a mixture of Ar and H2 is introduced. The carbon is treated with dielectric barrier discharge plasma for 30 minutes to obtain pretreated activated carbon. The power of the dielectric barrier discharge plasma varies periodically within the range of 400 to 600 W, with a frequency of 20 W / 5 min. The volume ratio of Ar to H2 in the mixture is 9:1.

[0058] Example 8: The difference between this example and Example 6 is that the pretreatment of the composite activated modified activated carbon is different. Specifically, the wood-based activated carbon that has been washed and removed of impurities with water is placed in a reactor, and a mixture of Ar and H2 is introduced. The carbon is treated with dielectric barrier discharge plasma for 45 minutes to obtain pretreated activated carbon. The power of the dielectric barrier discharge plasma varies periodically within the range of 400 to 600 W, with a frequency of 50 W / 5 min. The volume ratio of Ar to H2 in the mixture is 8:2.

[0059] Example 9: This example is different from Example 6 in that the modification treatment of the composite activated modified activated carbon is different. Specifically, the pretreated activated carbon and water are placed in a supercritical state of water at a mass ratio of 1:8 for 20 minutes. During the treatment, 1m 3 O2 was added at a flow rate of 0.5 m / h for 5 min, followed by O3 3 O3 was added at a flow rate of / h until the treatment was completed, and then cooled to room temperature and separated to obtain composite activated modified activated carbon, wherein the supercritical state of the water was a temperature of 374°C and a pressure of 22.1 MPa.

[0060] Example 10: This example is different from Example 6 in that the modification treatment of the composite activated modified activated carbon is different. Specifically, the pretreated activated carbon and water are placed in a supercritical state of water at a mass ratio of 1:12 for 40 minutes. During the treatment, 3m 3 O2 was added at a flow rate of 1m / h for 10 min, followed by O3 3 O3 was added at a flow rate of / h until the treatment was completed, and then cooled to room temperature and separated to obtain composite activated modified activated carbon, wherein the supercritical state of the water was a temperature of 420°C and a pressure of 28 MPa.

[0061] Filter Experiment:

[0062] Driven by a peristaltic pump, a filtration-adsorption synergistic performance experiment was conducted on a microfluidic chip with a manta ray biomimetic filtration blade structure (filtration was pretreatment, and the filtration and adsorption layer in Example 1 was subsequently connected). Taking the angle between the first filter surface and the support rod as an example, the setting of the manta ray biomimetic filtration blade structure was explored. Three angle schemes between the leading edge and the support rod were designed: 10°±2°, 15°±2°, and 25°±2°. The effect of the angle on filtration efficiency and subsequent PFAS adsorption performance was systematically investigated. The specific angle schemes are as follows:

[0063] Experimental Example 1: A manta ray biomimetic filter chip with a leading edge angle of 10°±2° was set. During the experiment, the peristaltic pump parameters were set to 0.05-5.6L / min, the inlet flow rate was 0.35-11.11m / s, the flow field Reynolds number (Re) was about 10-990, and the mixed solution used a 20μm fluorescent particle suspension loaded with PFAS (concentration 3μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid (particles aggregated in the main channel, and the clarified liquid containing PFAS flowed out through the channels on both sides of the filter layer) was collected and flowed through the filter adsorption layer (three-layer adsorption layer). The results showed The filtration efficiency increases slowly with the increase of the inlet flow rate. At a low flow rate of 0.05L / min, the filtration efficiency is about 32% (only 32% of the particles are intercepted), and the PFAS removal rate is about 64%. At a high flow rate of 5.6L / min, the filtration efficiency rises to 69%, and the total removal rate is about 81%. The mechanism analysis shows that the 10° angle is too small, the vortex strength at the leading edge of the blade bending is weak, and the inertia force of PFAS particles at low flow rates is insufficient, making it difficult to effectively gather in the main channel, resulting in a large number of particles entering the secondary channel with the fluid. Subsequent adsorption causes the adsorption layer to become clogged, the pollutant PFAS has insufficient contact with the material, and the removal rate is low. At the same time, due to the small angle, the filter layer cannot effectively intercept suspended particulate matter (sludge, etc.), resulting in contamination of the adsorption layer, reducing the adsorption efficiency and the service life of the filter layer.

[0064] Experimental Example 2: A manta ray biomimetic filter chip with a leading edge angle of 15°±2° was set. During the experiment, the peristaltic pump parameters were set to 0.05-5.6L / min, the inlet flow rate was 0.35-11.11m / s, the flow field Reynolds number (Re) was about 10-990, and the mixed solution used a 20μm fluorescent particle suspension loaded with PFAS (concentration 3μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid (particles aggregated in the main channel, and the clarified liquid containing PFAS flowed out through the channels on both sides of the filter layer) was collected and flowed through the filter adsorption layer (three layers of adsorption layer). The results showed that the filtration efficiency increased with the inlet flow rate. The increase in the angle of 15° increases the filtration efficiency to about 45% (13% increase compared to the 10° solution) at a low flow rate of 0.05L / min, and the total removal rate is about 71%. The filtration efficiency rises to 78% (9% increase compared to the 10° solution) at a high flow rate of 5.6L / min, and the total removal rate is about 89%. The mechanism analysis shows that the 15° angle optimizes the vortex intensity in the low flow rate range, enhances the aggregation effect of PFAS particles, reduces the escape of particles in the side channel, and improves the contact efficiency during subsequent adsorption. However, at high flow rates, the vortex is easily dispersed by the fluid, and some PFAS particles can still pass through the blade gaps, resulting in suboptimal adsorption removal rate. In addition, the 15° angle can better intercept suspended particulate matter and reduce its entry into the adsorption layer, thereby improving the removal efficiency of PFAS by the adsorption layer and extending the service life of the filter layer. At high flow rates, due to insufficient vortex stability, some suspended particulate matter may still pass through the side channel, affecting the effect of the adsorption layer.

[0065] Experimental Example 3: A manta ray biomimetic filter chip with a leading edge angle of 25°±2° was set. During the experiment, the peristaltic pump parameters were set to 0.05-5.6L / min, the inlet flow rate was 0.35-11.11m / s, the flow field Reynolds number (Re) was about 10-990, and the mixed solution used a 20μm fluorescent particle suspension loaded with PFAS (concentration 3μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid (particles were aggregated in the main channel, and the clarified liquid containing PFAS flowed out through the channels on both sides of the filter layer) was collected and flowed through the filter adsorption layer (three-layer adsorption layer). The results showed that the filtration efficiency increased significantly linearly with the increase of the inlet flow rate. At a low flow rate of 0.05L / min, the filtration efficiency was about 58% (compared to 1 The 25° angle improves the filtration efficiency by 12% compared to the 5° solution), with a total removal rate of about 91%. At a high flow rate of 5.6L / min, the filtration efficiency is as high as 90% (a 10% increase compared to the 15° solution), and the total removal rate is about 98% (almost complete removal). Mechanism analysis shows that the 25° angle makes the vortex strength at the leading edge of the blade bend moderate and stable. At low flow rates, the vortex can effectively capture PFAS particles (when the inertial force is weak, the vortex assists in aggregation), reducing escape from the side channels. At high flow rates, the vortex is not easily dispersed and the inertial force of the particles is enhanced. The synergistic effect of the two causes 92% of PFAS particles to aggregate in the main channel, and the subsequent adsorption layer can fully contact and capture the remaining PFAS, achieving the synergistic effect of "filtration aggregation + adsorption deep removal", and the final adsorption removal rate reaches 99%. In addition, the 25° angle optimizes the interception effect of the filter layer on suspended particulate matter, enabling the adsorption layer to efficiently adsorb PFAS. At the same time, the filter column is not easily clogged, extending its service life. At high flow rates, each layer of the manta ray structure can better generate small vortices, so that suspended matter and particulate matter will not pass through the side channels, but will flow directly to the bottom through the main channel, thereby further improving the filtration efficiency and adsorption layer performance.

[0066] See Figure 7 、 Figure 8By comprehensively comparing the results of Experimental Examples 1, 2, and 3, it can be seen that the manta ray bionic structure design with an angle of 25°±2° performs best: the filtration efficiency of this scheme in the full flow range of 0.05-5.6L / min (58%-92%) is significantly higher than that of the 10° (32%-69%) and 15° (45%-78%) schemes, especially at high flow rates (5.6L / min), the filtration efficiency is 10% higher than that of the 15° scheme; the improvement in filtration efficiency directly drives the improvement in subsequent adsorption removal rate. The adsorption removal rate of the 25° scheme reaches 99% at a high flow rate of 5.6L / min (an increase of 9% compared with the 15° scheme), and the total removal rate is close to complete. Mechanism analysis shows that the 25° angle optimizes the synergistic effect of the vortex intensity at the bend of the blade and the inertial force of the suspended particles, avoiding the insufficient aggregation at low flow rates caused by the weak vortex at a 10° angle, and overcoming the defect of easy dispersion of vortices at high flow rates at a 15° angle, thus achieving efficient filtration of "vortex-assisted aggregation + inertial interception". The optimized structure allows suspended particles to be more concentrated in the main channel, effectively reducing the escape of side channels and the clogging of the adsorption layer, providing ideal conditions for the aggregation of high-concentration particles in the subsequent adsorption layer, extending the life of the filter column and maximizing the adsorption efficiency. In summary, the 25°±2° leading edge angle of the manta ray biomimetic filtration structure achieves a PFAS removal rate of 99% through the "filtration-adsorption" synergistic effect, providing a key structural design basis and performance guarantee for the application of microfluidic chips in the treatment of PFAS-contaminated water bodies.

[0067] At the same time, in order to further explore the effects of the use of two modified activated carbons in the filter, a comparative experiment was conducted. The manta ray bionic filter blade structure was the same, and the third layer of 100-mesh modified activated carbon was designed to be ordinary activated carbon, restricted water modified activated carbon, and composite activated modified activated carbon. Three different loading schemes of activated carbon were designed to systematically investigate the filtration effects of different activated carbons. The specific schemes are as follows:

[0068] Experimental Example 4: The third layer of the filter adsorption layer was set to 100 mesh ordinary activated carbon. The peristaltic pump parameters were set to 0.05-5.6 L / min, the inlet flow rate was 0.35-11.11 m / s, the flow field Reynolds number (Re) was about 10-990, and the mixed solution was a 20 μm fluorescent particle suspension loaded with PFAS (concentration 3 μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid was collected (the main channel aggregated particles, and the fluid containing PFAS was discharged through the channels on both sides of the filter layer). PFAS clarified liquid) flowed through the filtration adsorption layer (three-layer adsorption layer). The results showed that the filtration efficiency increased significantly linearly with the increase of the inlet flow rate. At a low flow rate of 0.05L / min, the filtration efficiency was about 46%, and the total removal rate was about 74%. At a high flow rate of 5.6L / min, the filtration efficiency was as high as 81%, and the total removal rate was about 89%. Mechanism analysis showed that ordinary activated carbon does not have a hydrophilic adsorption effect. The adsorption effect of three layers of ordinary activated carbon with different mesh sizes is relatively limited and cannot meet reasonable expectations.

[0069] Experimental Example 5: The third layer of the filtration adsorption layer is set to be limited water modified activated carbon. During the experiment, the peristaltic pump parameters are set to 0.05-5.6L / min, the inlet flow rate is 0.35-11.11m / s, the flow field Reynolds number (Re) is about 10-990, and the mixed solution uses a 20μm fluorescent particle suspension loaded with PFAS (concentration 3μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid (particles are aggregated in the main channel, and the clarified liquid containing PFAS flows out through the channels on both sides of the filter layer) and flows through the filtration adsorption layer ( The results showed that the filtration efficiency increased significantly linearly with the increase of inlet flow rate. At a low flow rate of 0.05L / min, the filtration efficiency was about 58%, and the total removal rate was about 91%. At a high flow rate of 5.6L / min, the filtration efficiency was as high as 90%, and the total removal rate was about 98%. The mechanism analysis showed that the restricted water modified activated carbon had stronger adsorption performance than ordinary activated carbon. The combined adsorption of two layers of ordinary activated carbon with different mesh sizes + one layer of restricted water modified activated carbon had a significantly improved filtration effect compared with ordinary activated carbon.

[0070] Experimental Example 6: The third layer of the filtration adsorption layer was set to composite activated modified activated carbon. During the experiment, the peristaltic pump parameters were set to 0.05-5.6 L / min, the inlet flow rate was 0.35-11.11 m / s, the flow field Reynolds number (Re) was approximately 10-990, and the mixed solution was a 20 μm fluorescent particle suspension loaded with PFAS (concentration 3 μg / L) (simulating turbid water contaminated with PFAS); the filtered fluid (particles aggregated in the main channel, and clear liquid containing PFAS flowing out through the channels on both sides of the filter layer) was collected and flowed through the filtration adsorption layer (three-layer adsorption layer) The results showed that the filtration efficiency increased significantly linearly with increasing inlet flow rate. At a low flow rate of 0.05L / min, the filtration efficiency was approximately 64%, and the total removal rate was approximately 95%. At a high flow rate of 5.6L / min, the filtration efficiency was as high as 93%, and the total removal rate was approximately 99% (essentially complete removal). Mechanism analysis showed that the adsorption effect of the combined adsorption of two layers of ordinary activated carbon with different mesh sizes and one layer of composite activated modified activated carbon was significantly improved compared to ordinary activated carbon. At the same time, the filtration effect at low flow rates was also significantly improved compared to limited water modified activated carbon. It can be seen that by using limited water modified activated carbon or composite activated modified activated carbon as the third adsorption layer of the filtration adsorption layer, a stronger adsorption and removal effect of PFAS can be achieved. At the same time, using composite activated modified activated carbon as the third adsorption layer can also achieve a stronger PFAS adsorption and removal efficiency at low flow rates, thereby reducing the driving power consumption of the peristaltic pump and making it have lower water flow rate requirements when used for indoor water filtration and purification.

Claims

1. Anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water, characterized by: The filter comprises a shell (1), and a manta ray biomimetic filter structure (2), an inner support (3), a filter adsorption layer (4), and an outer support (5) which are sequentially arranged in the shell (1) from the inside to the outside; the shell (1) is provided with a water inlet (11) communicating with the upper end of the manta ray biomimetic filter structure (2), a water outlet (12) communicating with the filter adsorption layer (4), and a sewage outlet (13) communicating with the lower end of the manta ray biomimetic filter structure (2), and the sewage outlet (13) has a sewage valve.

2. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 1 is characterized in that: The manta ray bionic filtering structure (2) is composed of a plurality of filter discs (21) stacked at intervals, and each filter disc (21) is connected and fixed by a plurality of support rods (22). The filter disc (21) has an annular structure, is bent downward, and is divided into a first filter surface (211), a second filter surface (212), and a third filter surface (213) from the inside to the outside through two bends.

3. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 2 is characterized in that: The angle between the first filter surface (211) and the support rod (22) is 20-25°, the angle between the second filter surface (212) and the vertical direction is 40-45°, and the angle between the third filter surface (213) and the vertical direction is 30-35°.

4. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 2 is characterized in that: The filter disc (21) is circumferentially provided with a plurality of radially arranged micro grooves (214).

5. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 1 is characterized in that: The filter adsorption layer (4) is composed of a PP cotton filter layer (41) and an activated carbon adsorption layer (42), wherein the PP cotton filter layer (41) is PP cotton, and the activated carbon adsorption layer (42) is activated carbon of three different mesh sizes, and the distribution of the PP cotton filter layer (41) and the activated carbon adsorption layer (42) is as follows: from the inside to the outside, they are composed of PP cotton, 60 mesh activated carbon, PP cotton, 100 mesh activated carbon, PP cotton, 200 mesh activated carbon and PP cotton.

6. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 5, characterized in that: The activated carbon adsorption layer (42) is three types of activated carbon with different mesh sizes, specifically, 60-mesh activated carbon, 100-mesh activated carbon and 200-mesh activated carbon. The 60-mesh activated carbon and 100-mesh activated carbon are both ordinary activated carbon, and the 200-mesh activated carbon is modified activated carbon.

7. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 6, characterized in that: The modified activated carbon is limited water modified activated carbon or composite activated modified activated carbon.

8. The anti-fouling and high-efficiency filter for adsorbing high-risk pollutants in water according to claim 7, characterized in that: The preparation method of the composite activated modified activated carbon is: 1) The wood-based activated carbon that has been washed and impurities removed with water is placed in a reactor, a mixture of Ar and H2 is introduced, and a dielectric barrier discharge plasma is used for treatment for 30 to 45 minutes to obtain pretreated activated carbon. The power of the dielectric barrier discharge plasma is periodically varied within a range of 400 to 600 W at a frequency of 20 to 50 W / 5 minutes. 2) The pre-treated activated carbon and water are placed in a supercritical state of water at a mass ratio of 1:8-12 for 20-40 minutes, and during the treatment, 1-3 m 3 / h to add O2 for 5 to 10 minutes, and then add O3 at a rate of 0.5 to 1 m 3 O3 was added at a flow rate of / h until the treatment was completed, and then cooled to room temperature to obtain composite activated modified activated carbon; The volume ratio of Ar to H2 in the mixed gas is (8-9): (2-1), and the supercritical state of water is at a temperature of 374-420°C and a pressure of 22.1-28 MPa.

9. A method for operating a filter that is resistant to fouling and clogging and can efficiently absorb high-risk pollutants in water, characterized in that: The filter according to any one of claims 1 to 8 comprises the following steps: S1. Connect the water pipe to the water inlet (11) of the filter so that the water pipe and the water outlet (12) are in a communicating state, and close the sewage valve so that the sewage outlet (13) and the water inlet (11) are in a closed state; S2, water is injected through the water inlet (11), and the water flows along the main channel in the middle of the manta ray bionic filtration structure (2), and flows through the multi-layer separation structure gaps formed between the filter discs (21) to the filtration adsorption layer (4). Under the action of water pressure, the water passes through the filtration adsorption layer (4) to complete the separation of particles in the incoming water, pre-filtration, adsorption and post-filtration, and finally the purified water is discharged through the water outlet (12); S3. When the filter adsorption layer (4) is contaminated, the drain valve is opened to open the drain outlet (13), and water is injected along the water inlet (11), passes through the main channel of the manta ray bionic filter structure (2) and the gaps in the multi-layer separation structure, and flows out of the drain outlet (13) from the lower end of the filter, completing the flushing of the particles attached to the filter adsorption layer (4) in the filter and the discharge of the separated particles, thereby completing the filter drainage.

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