A modified flocked biological filler, its preparation method and application

Abstract

This application relates to a method for preparing a modified flocked biological packing material, comprising the following steps: (1) bombarding the surface of the biological packing material with nitrogen plasma; (2) in-situ polymerization of flocking adhesive; (3) electrostatic flocking; (4) curing; to obtain the modified flocked biological packing material. The biological packing material prepared by the method of this invention has abundant short fibers on its surface, which is conducive to the reproduction and growth of microorganisms, and the flocking adhesive is tightly bonded to the biomaterial substrate, without any problem of detachment. The application of the modified flocked biological packing material is also disclosed. Applying this biological packing material to a fixed-bed reactor can solve the problem of long reactor start-up time, while improving the microbial biofilm formation effect and ensuring the long-term stability of activated sludge operation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, specifically to a modified flocked biological packing material, its preparation method, and its application in the field of biological water treatment technology. Background Technology

[0002] Biofilm technology is a highly efficient wastewater treatment process with significant advantages in degrading organic pollutants in municipal sewage, domestic sewage, and organic industrial wastewater. It also possesses excellent nitrogen and phosphorus removal capabilities. However, this method suffers from long start-up times and slow biofilm formation. The addition of biological packing material enables rapid biofilm formation, thereby increasing the reaction rate, improving pollutant removal and nitrogen removal efficiency, and ensuring the stable and efficient operation of the wastewater treatment system. This makes it of significant application value.

[0003] Biological packing materials have smooth surfaces and require modification to enhance their ability to adhere to microorganisms. Currently, the common modification method for biological packing materials is to activate the carrier surface with chemical reagents, which generates a large amount of wastewater and pollutes the environment. Plasma technology uses plasma, an ionized gas containing positive ions, negative ions, or electrons, to pretreat the material surface and introduce functional groups. This method requires no solvents or water and is environmentally friendly.

[0004] Electrostatic flocking technology uses a high-voltage electrostatic field to cause short fibers to move directionally under the influence of the electric field force, vertically and uniformly implanting them onto a carrier with an adhesive. After curing and drying, the short fibers are fixed to the carrier. The short fibers can improve the carrier's biofilm formation ability, which is beneficial to the growth and reproduction of microorganisms.

[0005] Chinese patent CN203307107U discloses a honeycomb modified biological filler for water treatment. The filler is made of a polymer substrate, and its inner and outer surfaces have activated carbon particles, volcanic ash particles, or diatomaceous earth particles that create an uneven surface. The introduction of these particles enhances the filler's hydrophilicity, surface wettability, and mass transfer properties. The particles also increase the material's specific surface area, which is beneficial for microbial attachment and growth. However, this invention is relatively expensive.

[0006] Chinese patent CN1070984A discloses a method for preparing a biological rope bio-filler made of modified hydrophilic synthetic fibers. The bio-rope is a ring-shaped fiber made of a central rope and outer fibers. It is composed of a variety of fiber materials. Through physical and chemical modification of these fiber materials, voids, micropores and polar groups are introduced into these fiber materials to increase the specific surface area of ​​the bio-rope by multiple times. Through surface effect adsorption of water molecules, the biological treatment effect of the bio-rope bio-filler is greatly improved. However, its strength is insufficient, its support is poor and its circulation performance is poor.

[0007] Chinese patent CN104445587B discloses a method for preparing high-density suspended filler. The method involves uniformly mixing vinyl resin granules with nano-inorganic fillers and antioxidants, then extruding the mixture using a screw extruder. The mixture is then shaped using a mold and flocked using an electrostatic flocking device. Hollow fibers are bonded to the surface of the vinyl resin granular honeycomb filler, forming a filler with a layer of neatly arranged hollow fibers on its surface, thus creating a high-density suspended filler. While this method offers the advantage of low cost, the use of chemical reagents causes environmental pollution. Summary of the Invention

[0008] To address the problems of long start-up cycles, slow biofilm formation, and easy biofilm detachment in existing water treatment biological fillers, this invention provides a method for modifying biological fillers. The method involves pretreating the material surface using plasma, performing in-situ polymerization of a flocking adhesive, then arranging short fibers on the surface using an electrostatic flocking process, and finally fixing the short fibers to the material surface through a curing process. The biological filler prepared by this method has abundant short fibers on its surface, which is beneficial for the reproduction and growth of microorganisms. Furthermore, the flocking adhesive bonds tightly to the biomaterial substrate, eliminating the problem of biofilm detachment.

[0009] The technical solution of this invention is:

[0010] A method for preparing a modified flocked biological filler, the specific steps of which are as follows:

[0011] (1) N plasma bombards the surface of the biological packing material

[0012] 1) Use a mixed gas (N2 / H2) with low volume H2 (10-20%) as the gas carrier, and bombard the biological filler with 100-200W power for 0.5-1 hours to enrich the surface of the material with -NH2 or -NH groups.

[0013] This step can enrich the material surface with -NH2 or -NH groups.

[0014] (2) In-situ polymerized flocking adhesive

[0015] 1) Add 50 mL of diglycidyl ether to 100 g of inert solvent, mix well, and quickly immerse the biological filler treated in step (1) into the mixture. Reflux at 60 °C for 2-4 hours.

[0016] 2) Add curing agent dropwise to the reaction solution and continue stirring for 0.5-1 hour.

[0017] (3) Electrostatic flocking

[0018] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the short fibers into the upper electrode plate, with a distance of 7-15cm between the electrodes. Turn on the electrostatic processing equipment, with the electrostatic generator voltage at 40-100kV. Under the action of the high-voltage electric field, the short fibers fall vertically onto the carrier containing the flocking adhesive. After 0.1-1 hours, turn off the electrostatic processing equipment.

[0019] This step implants short fibers into the surface of the carrier.

[0020] (4) Curing

[0021] The carrier from step (3) was placed in a fume hood for air drying. After the surface was dried, it was placed in a nitrogen-protected oven at 60-80℃ for curing for 1-3 hours to obtain the modified flocked biological filler.

[0022] This invention introduces -NH2 or -NH groups onto the surface of biological filler using plasma technology, and then flocks short fibers onto the surface of the biological filler using an in-situ polymerized flocking adhesive in a flocking machine. This synthesis method has few process steps and is simple to operate.

[0023] Furthermore, the diglycidyl ether is one of polyethylene glycol diglycidyl ether 400, polyethylene glycol diglycidyl ether 1000, polyethylene glycol diglycidyl ether 2000, polyethylene glycol diglycidyl ether 6000, polypropylene glycol diglycidyl ether 380, and polypropylene glycol diglycidyl ether 640.

[0024] Furthermore, the inert solvent is one of ethyl acetate, tetrahydrofuran, chloroform, and dichloromethane.

[0025] Furthermore, the mass ratio of the diglycidyl ether to the inert solvent is 20-40:100.

[0026] Furthermore, the curing agent is one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

[0027] Furthermore, the molar ratio of the curing agent to diglycidyl ether is 2:3-4.

[0028] Furthermore, the fiber types include cotton fiber, viscose lint, nylon lint, acrylic fiber, polyester, etc.

[0029] Furthermore, the biological packing material has a radius of 15 mm, a height of 10 mm, is made of polyethylene, and has a specific surface area > 500 m². 2 / m 3 .

[0030] As a general technical concept, the present invention also provides an application of the modified biological packing material, which is used in a biological fixed-bed reactor, comprising the following steps:

[0031] (1) A certain amount of activated sludge and the above-mentioned modified flocked biological packing material are added to the biological fixed bed reactor.

[0032] (2) The system operates for 4 cycles per day, with each cycle lasting 6 hours. The specific operating times for each stage are: water inlet (10 min), anaerobic (350 min), water outlet (10 min), and aerobic (350 min). Each water inlet and outlet is 400 mL.

[0033] (3) After running for 10 days, observe the effect of the biological packing on the loading of microorganisms and test the removal effect of COD and ammonia nitrogen in the reactor.

[0034] The influent uses a laboratory wastewater formula, with glucose and sodium acetate as carbon sources, ammonium sulfate as a nitrogen source, and potassium dihydrogen phosphate as a phosphorus source. The wastewater COD load per unit MLSS is 0.4 kg / (kg·d). In addition, a small amount of trace elements are added to ensure the growth and metabolic activities of activated sludge.

[0035] Applying this biological packing material to a fixed-bed reactor can solve the problem of long reactor start-up time, while improving the biofilm formation effect and ensuring the long-term stability of activated sludge operation.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) The present invention uses plasma technology to bombard the surface of materials. Compared with the commonly used method of adding chemical reagents, it can reduce the use of chemical reagents, has fewer process steps, is simple to operate, and is environmentally friendly.

[0038] (2) The present invention polymerizes flocking adhesive on the surface of biological packing material in situ. After flocking, the short fibers of the biological packing material obtained by this method are firmly bonded and not easy to fall off. When applied to fixed bed reactors, it has better biofilm formation effect and resistance to hydraulic shock, which can reduce sludge loss and thus have better pollutant and ammonia nitrogen removal effect. Attached Figure Description

[0039] Figure 1 Fluorescence image of unmodified biological packing material attached to a biofilm;

[0040] Figure 2 Fluorescence image of the modified flocked biological packing membrane. Detailed Implementation

[0041] It is worth noting that the raw materials used in this invention are all commercially available products, and their sources are not specifically limited.

[0042] The following sources of raw materials are provided as examples:

[0043] Ethyl acetate, tetrahydrofuran, chloroform, and dichloromethane were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0044] Polyethylene glycol diglycidyl ether 400, polyethylene glycol diglycidyl ether 1000, polyethylene glycol diglycidyl ether 2000, polyethylene glycol diglycidyl ether 6000, polypropylene glycol diglycidyl ether 380, polypropylene glycol diglycidyl ether 640, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine were purchased from Aladdin Chemical Reagents.

[0045] The biological packing material was purchased from Qingdao Zhongke Juneng Environmental Protection Co., Ltd. It has a radius of 15mm, a height of 10mm, and is made of polyethylene with a specific surface area >500m³. 2 / m 3 .

[0046] Example 1:

[0047] (1) N plasma bombards the surface of the biological packing material

[0048] A mixed gas of 10% H2 (N2 / H2) was used as the gas carrier to bombard the biological packing material at 100W power for 1 hour, so that the surface of the biological packing material was rich in -NH2 or -NH groups.

[0049] (2) In-situ polymerized flocking adhesive

[0050] 1) Add 50 mL of polyethylene glycol diglycidyl ether 400 to 100 g of ethyl acetate, mix well, and quickly immerse the biological filler treated in step (1) into the mixture. Reflux at 60 °C for 2 hours.

[0051] 2) Add ethylenediamine dropwise to the reaction solution and continue stirring for 1 hour.

[0052] (3) Electrostatic flocking

[0053] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the cotton fibers into the upper electrode plate. The distance between the electrodes is 7 cm. Turn on the electrostatic processing equipment. The voltage of the electrostatic generator is 60 kV. Under the action of the high-voltage electric field, the cotton fibers fall vertically onto the carrier containing the flocking adhesive. After 0.2 hours, turn off the electrostatic processing equipment.

[0054] (4) Curing

[0055] The carrier from step (3) was placed in a fume hood for air drying. After the surface was dried, it was placed in a nitrogen-protected oven at 60°C for curing for 1 hour.

[0056] (5) Fixed-bed reactor

[0057] In a biological fixed-bed reactor, 50g of activated sludge and 0.25g of the modified flocked biological packing were added. The reactor was run for four cycles per day, each cycle lasting 6 hours. The specific operating times for each stage were: influent (10min), anaerobic (350min), effluent (10min), and aerobic (350min). Each influent and effluent volume was 400mL. After 10 days of operation, the microbial loading effect of the biological packing was observed, and the removal efficiency of COD and ammonia nitrogen in the reactor was tested.

[0058] Example 2:

[0059] (1) N plasma bombards the surface of the biological packing material

[0060] The preparation method is the same as in Example 1.

[0061] (2) In-situ polymerized flocking adhesive

[0062] The preparation method and dosage are the same as in Example 1, except that "polyethylene glycol diglycidyl ether 400" is replaced with "polypropylene glycol diglycidyl ether 380", "ethyl acetate" is replaced with "tetrahydrofuran", and "ethylenediamine" is replaced with "hexamethylenediamine".

[0063] (3) Electrostatic flocking

[0064] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the adhesive short fibers into the upper electrode plate. The distance between the electrodes is 7 cm. Turn on the electrostatic processing equipment. The voltage of the electrostatic generator is 100 kV. Under the action of the high-voltage electric field, the adhesive short fibers fall vertically onto the carrier containing the flocking adhesive. After 0.5 hours, turn off the electrostatic processing equipment.

[0065] (4) Curing

[0066] The preparation method is the same as in Example 1.

[0067] (5) Fixed-bed reactor

[0068] The cultivation method is the same as in Example 1, except that the amount of modified flocked biological filler added is replaced with "0.5g" instead of "0.25g".

[0069] Example 3

[0070] (1) N plasma bombards the surface of the biological packing material

[0071] A mixed gas of 20% H2 (N2 / H2) was used as the gas carrier to bombard the biological filler with 200W power for 1 hour, making the surface of the material rich in -NH2 or -NH groups.

[0072] (2) In-situ polymerized flocking adhesive

[0073] The preparation method and dosage are the same as in Example 1, except that “polyethylene glycol diglycidyl ether 400” is replaced with “polyethylene glycol diglycidyl ether 1000”, “ethyl acetate” is replaced with “chloroform”, and “ethylenediamine” is replaced with “diethylenetriamine”.

[0074] (3) Electrostatic flocking

[0075] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the nylon short fibers into the upper electrode plate, with a distance of 15cm between the electrodes. Turn on the electrostatic processing equipment, with the electrostatic generator voltage at 100kV. Under the action of the high-voltage electric field, the nylon short fibers fall vertically onto the carrier containing the flocking adhesive. Turn off the electrostatic processing equipment after 0.5 hours.

[0076] (4) Curing

[0077] The preparation method is the same as in Example 1.

[0078] (5) Fixed-bed reactor

[0079] The cultivation method is the same as in Example 1, except that the amount of modified flocked biological filler added is replaced with "1g" instead of "0.25g".

[0080] Example 4

[0081] (1) N plasma bombards the surface of the biological packing material

[0082] The preparation method is the same as in Example 1.

[0083] (2) In-situ polymerized flocking adhesive

[0084] The preparation method and dosage are the same as in Example 1, except that "polyethylene glycol diglycidyl ether 400" is replaced with "polyethylene glycol diglycidyl ether 2000", "ethyl acetate" is replaced with "dichloromethane", and "ethylenediamine" is replaced with "triethylenetetramine".

[0085] (3) Electrostatic flocking

[0086] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the acrylic fiber into the upper electrode plate. The distance between the electrodes is 10 cm. Turn on the electrostatic processing equipment. The voltage of the electrostatic generator is 80 kV. Under the action of the high-voltage electric field, the acrylic fiber falls vertically onto the carrier containing the flocking adhesive. Turn off the electrostatic processing equipment after 1 hour.

[0087] (4) Curing

[0088] The preparation method is the same as in Example 1.

[0089] (5) Fixed-bed reactor

[0090] The cultivation method is the same as in Example 1, except that the amount of modified flocked biological filler added is replaced with "1.5g" instead of "0.25g".

[0091] Example 5

[0092] (1) N plasma bombards the surface of the biological packing material

[0093] A mixed gas of 15% H2 (N2 / H2) was used as the gas carrier to bombard the biological filler with 200W power for 0.5 hours, making the surface of the material rich in -NH2 or -NH groups.

[0094] (2) In-situ polymerized flocking adhesive

[0095] The preparation method and dosage are the same, except that “polyethylene glycol diglycidyl ether 400” is replaced with “polyethylene glycol diglycidyl ether 6000” and “ethylenediamine” is replaced with “diethylaminopropylamine”.

[0096] (3) Electrostatic flocking

[0097] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the polyester into the upper electrode plate. The distance between the electrodes is 15cm. Turn on the electrostatic processing equipment. The voltage of the electrostatic generator is 100kV. Under the action of the high-voltage electric field, the polyester falls vertically onto the carrier containing the flocking adhesive. After 0.1 hours, turn off the electrostatic processing equipment.

[0098] (4) Curing

[0099] The carrier from step (3) was placed in a fume hood for air drying. After the surface was dried, it was placed in a nitrogen-protected 60°C oven for curing for 3 hours to obtain the modified flocked biological filler.

[0100] (5) Fixed-bed reactor

[0101] The cultivation method is the same as in Example 1, except that the amount of modified flocked biological filler added is replaced with "2g" instead of "0.25g".

[0102] Example 6

[0103] (1) N plasma bombards the surface of the biological packing material

[0104] A mixed gas of 20% H2 (N2 / H2) was used as the gas carrier to bombard the biological filler with 100W power for 1 hour, so that the surface of the material is rich in -NH2 or -NH groups.

[0105] (2) In-situ polymerized flocking adhesive

[0106] The preparation method and dosage are the same as in Example 1, except that “polyethylene glycol diglycidyl ether 400” is replaced with “polypropylene glycol diglycidyl ether 640”.

[0107] (3) Electrostatic flocking

[0108] Place the carrier from step (2) into the lower electrode plate of the flocking machine, and place the short fibers into the upper electrode plate, with a distance of 9 cm between the electrodes. Turn on the electrostatic processing equipment, with the electrostatic generator voltage at 40 kV. Under the action of the high-voltage electric field, the short fibers fall vertically onto the carrier containing the flocking adhesive. After 0.5 hours, turn off the electrostatic processing equipment.

[0109] (4) Curing

[0110] The carrier from step (3) was placed in a fume hood for air drying. After the surface was dried, it was placed in an 80°C oven under nitrogen protection for curing for 2 hours.

[0111] (5) Fixed-bed reactor

[0112] The cultivation method is the same as in Example 1, except that the amount of modified flocked biological filler added is replaced with "2.5g" instead of "0.25g".

[0113] Comparative Example 1

[0114] The difference from Example 1 is that the N plasma bombardment of the biological packing surface is not used in Example 1. The other steps are the same. The effect of the biological packing on microbial loading is observed, and the removal effect of COD and ammonia nitrogen in the reactor is tested.

[0115] Table 1 Comparison of application effects between the examples and comparative examples.

[0116]

[0117] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a modified flocked biological filler, characterized in that, Includes the following steps: (1) N plasma bombardment of the surface of biological packing material 1) Use a N2 / H2 mixed gas with a volume ratio of 10-20% H2 as a gas carrier, and bombard the biological filler with 100-200W power for 0.5-1 hours to enrich the surface of the material with -NH2 or -NH groups; (2) In-situ polymerized flocking adhesive 1) Add diglycidyl ether to 100g of inert solvent, mix well, and quickly immerse the biological filler treated in step (1) into the mixture and reflux at 60°C for 2-4 hours. 2) Add curing agent dropwise to the reaction solution and continue stirring for 0.5-1 hour; (3) Electrostatic flocking Place the biological filler treated in step (2) into the lower electrode plate of the flocking machine, and place the short fibers into the upper electrode plate. The distance between the electrode plates is 7-15cm. Turn on the electrostatic processing equipment. The voltage of the electrostatic generator is 40-100kV. Under the action of the high voltage electric field, the short fibers fall vertically onto the biological filler containing the flocking adhesive. After 0.1-1 hours, turn off the electrostatic processing equipment. (4) Curing The biological filler after step (3) is placed in a fume hood for air drying. After the surface is dry, it is placed in a nitrogen-protected oven at 60-80℃ for curing for 1-3 hours to obtain the modified flocked biological filler.

2. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The diglycidyl ether is one of polyethylene glycol diglycidyl ether 400, polyethylene glycol diglycidyl ether 1000, polyethylene glycol diglycidyl ether 2000, polyethylene glycol diglycidyl ether 6000, polypropylene glycol diglycidyl ether 380, and polypropylene glycol diglycidyl ether 640.

3. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The inert solvent is one of ethyl acetate, tetrahydrofuran, chloroform, and dichloromethane.

4. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The mass ratio of the diglycidyl ether to the inert solvent is 20-40:

100.

5. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The curing agent is one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, or diethylaminopropylamine.

6. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The molar ratio of curing agent to diglycidyl ether is 2:3-4.

7. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The short fibers are cotton fibers, viscose linters, nylon linters, acrylic fibers, or polyester fibers.

8. The method for preparing a modified flocked biological filler according to claim 1, characterized in that, The biological packing material has a radius of 15mm, a height of 10mm, is made of polyethylene, and has a specific surface area >500m². 2 / m 3 .

9. The application of the modified flocked biological packing prepared by the preparation method according to any one of claims 1-8, wherein the modified flocked biological packing is used in a biological fixed-bed reactor.

10. The application according to claim 9, characterized in that, Includes the following steps: (1) Add activated sludge and modified flocked biological packing material to the biological fixed-bed reactor; (2) The system operates for 4 cycles per day, with each cycle lasting 6 hours. The specific operating times for each stage are: 10 min for water inlet, 350 min for anaerobic digestion, 10 min for water drainage, and 350 min for aerobic digestion. Each water inlet and outlet is 400 mL. (3) Run for 10 days to remove COD and ammonia nitrogen.

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