A porous graphene-microorganism aggregate, a preparation method thereof and an adsorption device

Abstract

The present application belongs to the technical field of sewage treatment, and particularly relates to a porous graphene-microorganism aggregate, a preparation method thereof and an adsorption device. The technical scheme is as follows: a porous graphene-microorganism aggregate, which comprises a graphene block, a plurality of pores with multiple pore sizes are distributed in the graphene block, the graphene block comprises graphene oxide, polydopamine and polyethylene glycol, and active sludge bacteria are dispersed in the graphene block. The present application provides a porous graphene-microorganism aggregate with good transmission performance, a preparation method thereof and an adsorption device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a porous graphene-microorganism aggregate, a preparation method thereof and an adsorption device. BACKGROUND

[0002] With the development of society, water pollution is becoming more and more serious, and pollutants such as N and P in water bodies have a huge impact on the water environment, bringing great difficulties to sewage treatment. The activated sludge method has been effectively applied in water treatment. However, the activated sludge method also has some disadvantages in treatment, such as: 1) the bacteria in the sludge need to be cultured or inoculated for a certain period of time; 2) the sludge is easy to swell, causing water pollution and affecting the water treatment effect; 3) the sludge cannot be modularized, and the post-treatment is difficult; 4) the treatment method is not flexible, and cannot be adjusted according to local conditions and treated at any time; 5) the traditional activated sludge method occupies a large area, and the treatment method is not flexible and the operation is cumbersome.

[0003] The 3D printing technology provides a new microorganism immobilization technology, and provides an innovative design of a bioactive structure containing microorganisms for environmental pollution repair. The bacteria in the activated sludge are printed into a modularized activated sludge by 3D printing, and the modularized activated sludge contains growing activated sludge bacteria, which can effectively grow in sewage.

[0004] Graphene material has excellent performance in water treatment and has large mechanical strength. The activated sludge bacteria are combined with graphene and printed into a three-dimensional graphene structure. The loose and porous structure of graphene is beneficial to the adhesion and growth of bacteria, and can realize the degradation of pollutants in water in the biological treatment method of bacteria. The excellent performance of graphene can also effectively adsorb heavy metals and some difficult biodegradable organic matter in water, realizing the maximum removal of organic matter in water. Moreover, the problem of sludge bulking of suspended activated sludge is avoided. Although researchers have tried to use graphene mixed with bacteria to treat sewage, in general, the results of bacterial treatment of sewage depend largely on the transmission of organic matter in sewage by graphene channels. However, the current technology largely utilizes the transmission of organic matter by graphene itself, and reasonable transmission requires reasonable channel distribution and appropriate macropore, mesopore and micropore distribution. The channels of graphene have reached a bottleneck in the traditional 3D printing preparation method (such as grid-shaped and cylindrical), and cannot achieve a reasonable pore size distribution state. SUMMARY

[0005] In order to solve the above problems existing in the prior art, the purpose of the present application is to provide a porous graphene-microorganism aggregate with good transmission performance, a preparation method thereof and an adsorption device.

[0006] The technical scheme adopted by the present application is:

[0007] A porous graphene-microorganism aggregate comprises a graphene block, a plurality of pores with multi-stage pore diameters are distributed in the graphene block, the graphene block comprises graphene oxide, polydopamine and polyethylene glycol, and activated sludge bacteria are dispersed in the graphene block.

[0008] The graphene block of the present application is distributed with a plurality of pores with multi-stage pore diameters, and these multi-stage porous structures have a more reasonable distribution of large pores, mesopores and micropores, and different pore types have different functions, such as the large pores only play a mass transfer role. It is because of the reasonable distribution of large pores, mesopores and micropores that the nutrient transport and surface performance of these natural materials are greatly improved. The present application breaks through the adsorption bottleneck of traditional 3D graphene, and has better transport performance.

[0009] The present application adopts dopamine and polyethylene glycol as bioactive substances, and mixes the main bacteria (nitrifying bacteria, denitrifying bacteria) in the activated sludge and graphene. Due to the double crosslinking effect of dopamine and polyethylene glycol, the graphene microchannel is more developed and stable, the molecular chains of each other grow alternately, and a more stable microstructure is provided, so that the macroscopic body has better mechanical properties.

[0010] Compared with the traditional activated sludge method, the cultivation and growth of the bacteria of the present application are more stable. The technology is to print and fix the cultured activated sludge bacteria into the porous graphene skeleton crosslinked by dopamine and polyethylene glycol, which is beneficial to the growth and adhesion of nitrifying bacteria and denitrifying bacteria.

[0011] As a preferred scheme of the present application, the multi-stage pore diameter porous structure of the graphene block forms a loofah structure. The microstructure of the present application is a loofah structure, and through 3D printing, the inside is a loofah-like multi-stage porous structure, which is more conducive to the adsorption of pollutants by graphene, so that the fixed microorganisms in the graphene can better treat the pollutants.

[0012] As a preferred scheme of the present application, the graphene block is spherical. The macroscopic structure of the present application is spherical, which not only improves the specific surface area, but also provides conditions for the bacteria to treat pollutants in water, and has the advantages of not causing sludge expansion, polluting water bodies, and being easy to remove and recycle.

[0013] A preparation method of a porous graphene-microorganism aggregate comprises the following steps:

[0014] S1: preparing graphene oxide;

[0015] S2: preparing bio-ink for printing: dispersing graphene oxide prepared in step S1 into water under ultrasonic action, immediately adding polydopamine, continuously dispersing under ultrasonic action until uniform dispersion; slowly adding polyethylene glycol, stirring until the three substances are completely and uniformly dispersed; then pouring the active bacteria mixture in the cultivated sludge into the mixed solution, uniformly dispersing, and obtaining the bio-ink after stabilization;

[0016] S3: constructing a biomimetic structure: constructing a model structure of the graphene block in modeling software, and the graphene block is distributed with a plurality of pores of multiple pore sizes;

[0017] S4: printing a porous graphene-microorganism aggregate: using the bio-ink prepared in step S2, printing the porous graphene-microorganism aggregate according to the biomimetic structure constructed in step S3.

[0018] As a preferred scheme of the present application, in step S1, the specific steps for preparing graphene oxide are as follows:

[0019] S11: placing the graphene powder into a beaker under the condition of room temperature and no strong air flow disturbance;

[0020] S12: placing the graphene powder and the beaker in an ice bath environment; slowly adding sodium nitrate into the beaker containing the graphene powder under the condition of continuous ice bath; then adding sulfuric acid under the condition of stirring with a glass rod; stopping after sufficient stirring for 10 minutes; then adding potassium permanganate, and keeping the reaction temperature in the range of 23-25 DEG C; then controlling the temperature to be 30-40 DEG C, and stopping after continuous reaction for 30-40 min; then adding deionized water into the beaker, continuously stirring for 10-20 min, and then continuously adding hydrogen peroxide;

[0021] S13: placing the solution prepared in step S12 into a centrifuge, stopping after centrifugal treatment for 40-60 min; after taking out, continuously washing the residue with heated deionized water, and testing the washing solution with a pH meter until the pH value of the solution is 7;

[0022] S14: dispersing the cleaned residue powder into deionized water under ultrasonic action at room temperature, filtering with filter paper, obtaining uniformly distributed black suspension after filtering the black residue, and obtaining graphene oxide after volatilizing the black suspension at ice temperature.

[0023] As a preferred scheme of the present application, in step S3, the specific steps for constructing a biomimetic structure are as follows:

[0024] The porous structure of the graphene block distributed multi-stage pore is a loofah structure; the internal structure of the loofah is scanned by using a CT scanner; the model is simulated and completed by using modeling software; and the model is converted into STL language after being processed by the software and is exported to a 3D printer.

[0025] As a preferred scheme of the present application, in step S4, printing the porous graphene-microorganism aggregate comprises the following specific steps:

[0026] S41: taking the bio-ink prepared in step S2, placing it in a beaker, shaking it uniformly, then adding the prepared bio-ink sample to a printer cartridge, and then performing centrifugation to densify the ink; according to the biomimetic structure constructed in step S3, inputting the printing format from the computer end to the printer under the set program, printing layer by layer under the operation of the nozzle, and finally printing the porous graphene-microorganism aggregate with a spherical double-network skeleton structure;

[0027] S42: under the control of a thermostat, performing micro-low temperature freezing, and after expanding the pore, placing the graphene block in a temperature and humidity suitable for the growth of microorganisms to restore the inhibited activity.

[0028] An adsorption device comprises a device main body, a water inlet pipe is arranged at the lower part of the device main body, and a micro water pump is connected to the water inlet pipe; a water inlet hole plate, multiple partition plates, a water outlet hole plate and a baffle are arranged in the device main body, the partition plates are arranged on the upper side of the water inlet hole plate, a plurality of porous graphene-microorganism aggregates are arranged on the partition plates, the water outlet hole plate and the baffle are arranged on the upper side of the partition plates, the baffle comprises a sedimentation plate and a water outlet weir, and the water outlet hole plate and the sedimentation plate are spliced in the device main body; and a water outlet pipe is arranged at the upper part of the device main body.

[0029] The graphene block containing microorganisms printed in the present application is combined into the adsorption device, thereby greatly reducing the floor area, avoiding the defects of the traditional activated sludge method, such as large floor area and the need to separately arrange a sedimentation tank, and greatly improving the flexibility of the activated sludge in treating wastewater.

[0030] As a preferred scheme of the present application, the upper part of the water outlet weir is in a zigzag shape. The water outlet weir is arranged in a zigzag shape, mainly for uniform water distribution and stable flow rate, so as to prevent the water flow in the tank from being deflected and make the water outlet better sedimentation.

[0031] As a preferred scheme of the present application, the sedimentation plate is inclined downward in the direction close to the water outlet pipe. The sedimentation plate is slightly inclined, mainly for the concentration of sludge and the convenience of subsequent treatment.

[0032] The present application has the following beneficial effects:

[0033] 1. The graphene block of the present application has a plurality of pores with multi-stage pore sizes, and the multi-stage pore structure has a more reasonable distribution of macropores, mesopores and micropores, and different pore size types have different functions, such as macropores only play a mass transfer role. It is because of the reasonable distribution of macropores, mesopores and micropores that the nutrient transport and surface performance of the natural material are greatly improved. The present application breaks through the adsorption bottleneck of traditional 3D graphene, and has better transmission performance.

[0034] 2. The present application adopts dopamine and polyethylene glycol as bioactive substances, and mixes the main bacteria (nitrifying bacteria, denitrifying bacteria) in the activated sludge and graphene. Due to the double crosslinking effect of dopamine and polyethylene glycol, the graphene microchannel is more developed and stable, the molecular chains of each other interact and grow, providing a more stable microstructure, so that the macroscopic body has better mechanical properties.

[0035] 3. The macroscopic body of the present application is spherical, and the spherical macroscopic structure not only improves the specific surface area, but also provides conditions for bacteria to treat pollutants in water, and does not cause sludge expansion, pollution of water body, and easy removal and recovery.

[0036] 4. The present application avoids the problems of difficult treatment after use of activated sludge, compared with the traditional activated sludge method, the bacteria are printed into modular by the activated sludge method and printing technology, and after use, they can be easily removed from water. Compared with the traditional method, no sludge pipeline and equipment are needed, no sludge concentration and reuse are needed, and the subsequent treatment is simple.

[0037] 5. Compared with the traditional activated sludge method, the culture and growth of the bacteria of the present application are more stable. The technology is to directly print and fix the cultured activated sludge bacteria into the dopamine and polyethylene glycol crosslinked porous graphene skeleton, which is conducive to the growth and adhesion of nitrifying bacteria and denitrifying bacteria.

[0038] 6. The graphene block containing microorganisms printed in the present application is combined into an adsorption device, which greatly reduces the occupied area and avoids the shortcomings of traditional activated sludge method, such as large occupation of land and the need for separate setting of sedimentation tank. The technology combined with the device greatly improves the flexibility of activated sludge in treating wastewater, and the device can be moved to any place that needs to be treated.

[0039] 7. Compared with the traditional printing method, the fixed microorganism treatment technology realized by the present application can better reduce the biological toxicity of graphene due to the role of polyvinyl alcohol, which is more friendly to the environment.

[0040] 8. The present application combines treatment and sedimentation together, and has high degree of intensification. The device can be opened, disassembled, replaced with adsorption filler, etc., and is easy to operate. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural schematic diagram of the printed porous graphene-microorganism aggregate;

[0042] Figure 2 is a front view of the adsorption device;

[0043] Figure 3 is a partial structural diagram of the adsorption device;

[0044] Figure 4 is a structural schematic diagram of the baffle and the water outlet hole plate;

[0045] Figure 5 is a structural schematic diagram of the water outlet weir.

[0046] In the figure: 1 - activated sludge bacteria; 2 - graphene block; 3 - water inlet pipe; 4 - micro water pump; 5 - water inlet hole plate; 6 - partition plate; 7 - porous graphene-microorganism aggregate; 8 - water outlet pipe; 9 - device main body; 10 - water outlet hole plate; 11 - water inlet area; 12 - adsorption area; 13 - water outlet area; 14 - sedimentation area; 15 - baffle; 16 - valve; 151 - sedimentation plate; 152 - water outlet weir. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0049] Embodiment 1:

[0050] As shown in Figure 1 The porous graphene-microorganism aggregate 7 of the present embodiment includes a graphene block 2, a plurality of pores of multiple pore sizes are distributed in the graphene block 2, the graphene block 2 contains graphene oxide, polydopamine and polyethylene glycol, and activated sludge bacteria 1 are dispersed in the graphene block.

[0051] The graphene block 2 in the application is distributed with a plurality of pores with multi-stage pore sizes, the multi-stage porous structure has more reasonable macropore, mesopore and micropore distribution, and different pore size types have different functions, for example, the macropore only plays a mass transfer role. Because of the reasonable macropore, mesopore and micropore size distribution, the nutrient transport and surface performance of the natural material are greatly improved. The application breaks the adsorption bottleneck of the traditional 3D graphene, and makes the graphene have better transport performance.

[0052] The application adopts dopamine and polyethylene glycol as bioactive substances, and mixes the main bacteria (nitrifying bacteria, denitrifying bacteria) in the activated sludge and graphene. Due to the double crosslinking effect of dopamine and polyethylene glycol, the graphene microchannel is more developed and stable, the molecular chains of each other interact and grow, a more stable microstructure is provided, and the macroscopic body has better mechanical properties.

[0053] Compared with the traditional activated sludge method, the cultivation and growth of the bacteria in the application are more stable. The technology is to print and fix the cultured activated sludge bacteria 1 into the porous graphene skeleton crosslinked by dopamine and polyethylene glycol, which is beneficial to the growth and adhesion of nitrifying bacteria and denitrifying bacteria.

[0054] Bionics provides reference inspiration for the development of many disciplines, and can make different materials obtain the specific functions possessed by animals and plants in nature. These methods cannot be replaced by traditional methods. For example, the wax gourd, butterfly wings, pomelo peel and cancellous bone structure in nature have reasonable multi-stage porous distribution structure. The multi-stage porous structure has more reasonable macropore, mesopore and micropore distribution, and different pore size types have different functions, for example, the macropore only plays a mass transfer role. Because of the reasonable macropore, mesopore and micropore size distribution, the nutrient transport and surface performance of the natural material are greatly improved. If the suitable pore size distribution is applied to the 3D graphene structure, the adsorption bottleneck of the traditional 3D graphene can be broken, and the graphene has better transport performance.

[0055] In the embodiment, the multi-stage porous structure with multi-stage pore sizes of the graphene block 2 forms a wax gourd structure. The microstructure of the application is a wax gourd structure, and the inside of the 3D printing is a multi-stage porous structure similar to a wax gourd, which is more conducive to the adsorption of pollutants by graphene, so that the microorganisms fixed in the graphene can better treat the pollutants.

[0056] Furthermore, the graphene block 2 is spherical. The macroscopic structure of the application is a spherical ball, which not only improves the specific surface area, but also provides conditions for the bacteria to treat pollutants in water, and has the advantages of not causing sludge expansion, polluting water bodies, and being easy to remove and recycle.

[0057] Embodiment 2:

[0058] The preparation method of the porous graphene-microorganism aggregate 7 of the present embodiment uses materials including:

[0059] 1) Active sludge bacteria 1: nitrifying bacteria (nitrite bacteria: Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosolobus, etc.); denitrifying bacteria, including Escherichia coli, Proteus, Lactococcus acidophilus, Bacillus subtilis, and nitrate-degrading bacteria.

[0060] 2) Biologically active substances: polydopamine (PDA), polyethylene glycol.

[0061] 3) Skeleton: graphene block 2 (GO).

[0062] The preparation method of the present embodiment includes the following steps:

[0063] S1: Preparation of graphene oxide:

[0064] The preparation of graphene oxide refers to the conventional Hummer method, which is as follows:

[0065] S11: Under the condition of no strong air flow disturbance at room temperature, 4g of uniformly distributed and well-dispersed graphene powder is uniformly poured into a 500ml beaker.

[0066] S12: The dispersed graphene is placed in an ice bath environment of 0℃ to -1℃ (the ice bath temperature is controlled by a refrigerator to maintain a constant temperature, and the ice bath liquid is an ice-water mixture). Under the condition of continuous ice bath, 2g of sodium nitrate (NaNO3) is slowly added to the beaker containing the dispersed graphene, and then 60ml of sulfuric acid (H2SO4, 98%) is added while stirring with a glass rod. Finally, after slow and thorough stirring for ten minutes, stop. Then add 12g of potassium permanganate, and keep the reaction temperature in the range of 23℃ to 25℃, continue to react for 10min, then control the temperature at about 35℃, and continue to react for 35min. Next, add 95ml of deionized water to the beaker and continue to stir for 15min. Next, continue to add 82min of hydrogen peroxide (H2O2, 3%, 60℃), at which time the solution is brown-black.

[0067] S13: The brown-black solution prepared above is placed in a centrifuge (7000r / min), and the centrifugation is stopped after 50min. After taking out, the residue is continuously washed with heated deionized water (temperature 40℃ to 50℃), and the washing solution is tested with a pH meter until the pH value of the solution is 7.

[0068] S14: The cleaned residue powder is dispersed in 20 ml of deionized water at room temperature for 20 min under ultrasonic dispersion. After uniform dispersion, the mixture is filtered using filter paper. After filtering the black residue, a uniformly distributed black suspension is obtained. The black suspension is placed in a frozen temperature environment (-10°C) and evaporated to dryness to obtain graphene oxide.

[0069] S2: Preparation of a bio-ink for printing: 1.4 g of graphene oxide prepared in step S1 is dispersed in 30 ml of water under ultrasonic dispersion. Then, 1.2 g of a biocompatible material, polydopamine (PDA), is immediately added, and ultrasonic dispersion is continued until the three materials are uniformly dispersed. Then, another biocompatible material, polyethylene glycol, 0.8 g, is slowly added, and the mixture is stirred until the three materials are uniformly dispersed. The combination of the double cross-linking of polydopamine (PDA) and polyethylene glycol gives the graphene a stronger stable structure, and the polyethylene glycol reduces the biological toxicity of the graphene. Then, 10 ml of a mixture of active bacteria (nitrifying bacteria and denitrifying bacteria) in the sludge is added to the above mixture and uniformly dispersed to obtain a bio-ink.

[0070] S3: Construction of a biomimetic structure: The internal structure of the loofah is scanned using a CT scanner (Micro-CT (Y. CHEETAH, Germany)). Since the loofah is a symmetrical structure, only 1 / 4 of the cross-section is scanned. The model is simulated and completed using modeling software (CAD modeling and finite element analysis). To better print, all model structures are enlarged by 1.2 times, and regions exceeding 200 um and less than 30 um are not printed. After the model is processed in the software, it is converted to STL language and exported to a 3D printer. Under the control of the printer, a loofah-like structure with the same developed pore structure as the loofah is printed.

[0071] S4: Printing of porous graphene-microorganism aggregates 7:

[0072] S41: Printing of biologically fixed graphene skeleton:

[0073] The printer is selected to be a direct ink writing (DIW) printer. 30 ml of the prepared bio-ink is placed in a beaker and shaken until it is uniform. The bio-ink sample is then added to the printer cartridge, and the ink is densified by centrifugation for 3 min. The average printing speed is 1.5 mm / s, and the air pressure is 0.01-0.25 MPa. Under the set program, the printing format is input from the computer to the printer, and the printing is performed layer by layer under the operation of the nozzle. Finally, a double-network skeleton structure in the form of a spherical ball is printed.

[0074] S42: Freeze-drying and fixation:

[0075] This freezing method employs micro-low temperature controlled freezing, specifically described as follows: Under the control of a thermostat, the temperature is maintained slightly above zero degrees Celsius for 10 minutes of micro-low temperature freezing. After expanding the pores, in order to restore the inhibited activity of microorganisms, the graphene block 2 is placed at a temperature of 30°C suitable for microbial growth and kept at a suitable humidity for 15 minutes to allow it to revive, thus restoring the inhibited activity. The micro-low temperature and short freezing time ensure that appropriate pores are obtained without damaging the cell structure of microorganisms. The appropriate pore size expands the secondary transport of organic matter in the graphene structure, allowing the activated sludge bacteria 1 to better capture, absorb, and degrade it.

[0076] Printer parameters:

[0077] Output frequency: 0~999; Drive method: stepper; Number of input points: 1500; Number of output points: 1500; Repeatability: 0.01mm; X-axis travel: 200mm; Y-axis travel: 200mm; Z-axis travel: 100mm; Maximum load: 7kg; Movement speed: 800mm / s.

[0078] Example 3:

[0079] like Figures 2 to 5 As shown, the adsorption device of this embodiment includes a device body 9, with an inlet pipe 3 at the lower part of the device body 9, and a micro water pump 4 connected to the inlet pipe 3; the device body 9 is provided with an inlet perforated plate 5, multi-layer partitions 6, an outlet perforated plate 10 and a baffle 15, the partitions 6 are located above the inlet perforated plate 5, and a plurality of porous graphene-microorganism aggregates 7 are provided on the partitions 6, the outlet perforated plate 10 and the baffle 15 are located above the partitions 6, the baffle 15 includes a sedimentation plate 151 and an outlet weir 152, and the outlet perforated plate 10 and the sedimentation plate 151 are assembled in the device body 9; the device body 9 is provided with an outlet pipe 8 at the upper part.

[0080] The area below the inlet orifice plate 5 within the main body 9 of the device is the inlet area 11, and the inlet pipe 3 is connected to the inlet area 11. The area between the inlet orifice plate 5 and the outlet orifice plate 10 is the adsorption area 12. The area enclosed by the outlet weir 152 and the outlet orifice plate 10 is the outlet area 13; the area enclosed by the sedimentation plate 151 and the outlet weir 152 is the sedimentation area 14, and the outlet pipe 8 is connected to the sedimentation area 14. A valve 16 is connected to the outlet pipe 8.

[0081] Further, the upper part of the water outlet weir 152 is sawtooth-shaped. The water outlet weir 152 is sawtooth-shaped, mainly for uniform water distribution, smooth flow rate, and to prevent the water flow in the pool from being deflected, so that the water outlet is better settled. The settling area 14 is mainly for settling and removing the treated sewage containing some unremoved and generated metabolic waste. The printed graphene contains microorganism treatment, does not generate sludge itself, and therefore has a small settling pressure.

[0082] The water inlet plate hole not only has the effect of uniform water inlet, but also has the effect of intercepting suspended large particles and floating objects in sewage, and plays a pretreatment role. Similarly, the water outlet hole plate 10 of the water outlet area has the effect of secondary interception.

[0083] The main function of the partition plate 6 is to place the printed porous graphene-microorganism aggregate 7 in layers; it is circular and has a water inlet hole.

[0084] The settling plate 151 is inclined downward towards the water outlet pipe 8. The settling plate 151 has a slight inclination angle, mainly for the concentration of sludge to facilitate subsequent treatment.

[0085] Working process:

[0086] The sewage enters the water inlet area 11 through the suction of the micro pump through the water inlet pipe 3, and the sewage enters the adsorption area 12 after uniform water distribution by the water inlet hole plate 5. The adsorption area 12 is mainly composed of the partition plate 6 with a grid and the printed 3D porous graphene-microorganism aggregate 7 containing biological bacteria. The sewage is treated by the 3D graphene containing biological bacteria. This stage is an important stage of operation, mainly by the activated sludge bacteria 1 contained in the printed graphene block 2, and the microorganisms degrade the pollutants in the sewage. The clear water on the surface enters the water outlet area 13 through the water outlet hole plate 10, and the water in the water outlet area 13 enters the settling area 14 after uniform water distribution by the baffle 15 (the upper part of the baffle 15 is provided with a sawtooth-shaped water outlet weir), and the clear water flows out through the water outlet pipe 8 after sludge-water separation.

[0087] The printed graphene block 2 containing microorganisms of the present application is combined with the adsorption device, which greatly reduces the floor area and avoids the disadvantages of large floor area and the need for a separate settling tank in the traditional activated sludge method. The technology combined with the device greatly improves the flexibility of the activated sludge in treating sewage, and the device can be moved to any place that needs to be treated.

[0088] The present application is not limited to the above-mentioned optional embodiments, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in shape or structure, any technical solution falling within the scope of the claims of the present application falls within the scope of protection of the present application.

Claims

1. A method for preparing porous graphene-microbial aggregates, characterized in that: The porous graphene-microbial aggregate (7) is used to prepare a porous graphene-microbial aggregate (7), which includes a graphene block (2), the graphene block (2) containing graphene oxide, polydopamine and polyethylene glycol, and active sludge bacteria (1) dispersed in the graphene block (2). Includes the following steps: S1: Preparation of graphene oxide; S2: Preparation of bio-ink for printing: Disperse the graphene oxide prepared in step S1 into water under ultrasonic action, immediately add polydopamine, and continue ultrasonic dispersion until it is evenly dispersed; slowly add polyethylene glycol, stir evenly until the three substances are completely evenly dispersed; then pour the mixture of active bacteria in the cultivated sludge into the mixture, disperse evenly, and after stabilization, the bio-ink can be obtained. S3: Constructing a biomimetic structure: Constructing a model structure of graphene block (2) in modeling software, with several pores of multiple apertures distributed inside the graphene block (2); S4: Printing porous graphene-microbial aggregates (7): Using the bio-ink prepared in step S2, print porous graphene-microbial aggregates (7) according to the biomimetic structure constructed in step S3.

2. The method for preparing porous graphene-microbial aggregates according to claim 1, characterized in that: In step S1, the specific steps for preparing graphene oxide are as follows: S11: Pour graphene powder into a beaker at room temperature under conditions of no strong airflow disturbance; S12: Place the graphene powder and beaker in an ice bath environment; under continuous ice bath conditions, slowly add sodium nitrate to the beaker containing the graphene powder; then, while stirring with a glass rod, add sulfuric acid; stop stirring slowly and thoroughly for ten minutes; then add potassium permanganate and maintain the reaction temperature within the range of 23℃~25℃; then control the temperature at 30~40℃ and continue the reaction for 30~40 minutes; next, add deionized water to the beaker and stir continuously for 10~20 minutes, then continue to add hydrogen peroxide; S13: Place the solution prepared in step S12 in a centrifuge and centrifuge for 40-60 minutes. After centrifugation, remove the solution and continuously wash the residue with heated deionized water. Test the washing solution with a pH meter until the pH value of the solution is 7. S14: Disperse the cleaned residue powder in deionized water, ultrasonically disperse it evenly at room temperature, filter it with filter paper, and after filtering out the black residue, obtain a uniformly distributed black suspension; place the black suspension at a freezing temperature to evaporate it, and then obtain graphene oxide.

3. The method for preparing porous graphene-microbial aggregates according to claim 1, characterized in that: In step S3, the specific steps for constructing the biomimetic structure are as follows: The multi-level porous structure of the graphene block (2) is a loofah sponge structure; the internal structure of the loofah sponge is scanned using a CT scanner; the model is simulated and completed using modeling software; after the model is processed by the software, it is converted into STL language and exported to the 3D printer.

4. The method for preparing porous graphene-microbial aggregates according to claim 1, characterized in that: In step S4, printing porous graphene-microbial aggregates (7) includes the following specific steps: S41: Take the bio-ink prepared in step S2, place it in a beaker, shake it evenly, add the prepared bio-ink sample to the printer cartridge, and then centrifuge it to make the ink dense; according to the biomimetic structure constructed in step S3, under the set program, input the printing format from the computer to the printer, and print layer by layer under the operation of the printhead, and finally print a porous graphene-microorganism aggregate with a spherical double network skeleton structure (7). S42: Under the control of a thermostat, micro-low temperature freezing is performed. After the pores are expanded, the graphene block (2) is placed in a temperature and humidity suitable for microbial growth, so that the inhibited activity can be restored.

5. An adsorption device comprising the porous graphene-microbial aggregate (7) prepared by the method for preparing porous graphene-microbial aggregates according to claim 1, characterized in that: The device includes a main body (9), with an inlet pipe (3) at the bottom and a micro water pump (4) connected to the inlet pipe (3); the main body (9) is equipped with an inlet plate (5), a multi-layer partition (6), an outlet plate (10), and a baffle (15). The partition (6) is located on the upper side of the inlet plate (5), and several porous graphene-microorganism aggregates (7) are arranged on the partition (6). The outlet plate (10) and the baffle (15) are located on the upper side of the partition (6). The baffle (15) includes a sedimentation plate (151) and an outlet weir (152). The outlet plate (10) and the sedimentation plate (151) are assembled in the main body (9); the main body (9) is equipped with an outlet pipe (8).

6. An adsorption device according to claim 5, characterized in that: The upper part of the outlet weir has a sawtooth shape.

7. An adsorption device according to claim 5, characterized in that: The sedimentation plate (151) tilts downward toward the direction of the outlet pipe (8).

Images