A highly hydrophilic nano-iron-rich polyurethane bioaccumulation filler and its preparation method and application

Abstract

The present invention provides a highly hydrophilic nano-iron-rich polyurethane bio-enriched filler and its preparation method and application, belonging to the technical field of polyurethane foam fillers. The highly hydrophilic nano-iron-rich polyurethane bio-enriched filler provided by the present invention is prepared by including the following components in parts by mass: 50-70 parts of liquefied starch alcohol, component A, component B, and 0.2-0.3 parts of nano-iron powder; wherein component A includes: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst; component B includes: 123-125 parts of isocyanate and 0.1-0.3 parts of catalyst. The highly hydrophilic nano-iron-rich polyurethane bio-enriched filler provided by the present invention has good hydrophilicity and specificity, can better adsorb and enrich anaerobic ammonia-oxidizing bacteria, withstand large load shocks, is not easy to clog, ensures the stable operation of the treatment system, and thus improves the treatment efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane foam fillers, and in particular relates to a highly hydrophilic nano-iron-rich polyurethane bio-enriched filler, a preparation method and an application thereof. Background Art

[0002] In recent years, with the continuous advancement of industrialization and urbanization, urban sewage discharge and nitrogen and phosphorus pollutants have continued to increase, leading to low COD concentrations and eutrophication in domestic wastewater. Traditional activated sludge treatment technology commonly used in urban sewage treatment suffers from drawbacks such as sludge bulking, low activated sludge concentrations, prone to foaming, and poor effluent quality. Therefore, in previous sewage treatment plant denitrification and phosphorus removal upgrade projects, suspended biofilm formation was often introduced into the existing traditional activated sludge biological denitrification system to increase biomass and improve the volumetric efficiency of the reaction tank.

[0003] As a new type of biofilm carrier, polyurethane foam filler has excellent porosity and mechanical properties. It can not only promote the attachment and film formation of microorganisms, but also has the function of intercepting suspended solids and improving gas-water distribution, thereby improving the effect of sewage treatment.

[0004] Currently, a one-step method is usually used to prepare polyurethane foam fillers for sewage treatment, such as the patent application number CN202210054983. However, the above method only prepares hydrophilic clean fillers and cannot give the fillers specific functions to increase the richness of specific bacterial communities. Summary of the Invention

[0005] In view of this, the present invention aims to provide a highly hydrophilic, nano-iron-rich polyurethane bioaccumulator, its preparation method, and its application. The highly hydrophilic, nano-iron-rich polyurethane bioaccumulator provided by the present invention has good hydrophilicity and specificity, can better adsorb and enrich anaerobic ammonia-oxidizing bacteria, withstands large load shocks, is not prone to clogging, ensures stable operation of the treatment system, and thus improves treatment efficiency.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler, which is prepared by including the following components in parts by mass: 50-70 parts of liquefied starch alcohol, component A, component B, and 0.2-0.3 parts of nano-iron powder;

[0008] Component A comprises: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst;

[0009] Component B includes: 123-125 parts of isocyanate and 0.1-0.3 parts of catalyst.

[0010] Preferably, the preparation method of the liquefied starch alcohol comprises: mixing a liquefying agent, a catalyst and starch, and performing a liquefaction reaction to obtain the liquefied starch alcohol.

[0011] Preferably, the liquefier comprises glycerol and polyethylene glycol, and the mass ratio of the glycerol to the polyethylene glycol is 4:6 to 3:7.

[0012] Preferably, the gel catalyst in component A comprises a triethylenediamine solution.

[0013] Preferably, the foam stabilizer in component A includes L-580, G-580, and W-5903.

[0014] Preferably, the foaming agent in component A includes water.

[0015] Preferably, the catalyst in the B component includes dibutyltin dilaurate and stannous octoate.

[0016] The present invention also provides a method for preparing the highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler, comprising the following steps:

[0017] 1) mixing liquefied starch alcohol, component A, and nano iron powder to obtain a first mixed solution;

[0018] 2) mixing the first mixed solution obtained in step 1) with component B to obtain a second mixed solution;

[0019] 3) The second mixed solution obtained in step 2) is foamed and cured at high temperature to obtain a highly hydrophilic nano-iron-rich polyurethane bio-enriched filler.

[0020] Preferably, in step 3), the foaming temperature is 20-25° C., and the foaming time is 20-40 minutes; the high-temperature curing temperature is 150-200° C., and the high-temperature curing time is 1-2 hours.

[0021] The present invention also provides the use of the highly hydrophilic nano-iron-rich polyurethane bio-enrichment filler in sewage treatment.

[0022] Beneficial effects of the present invention:

[0023] 1. As a novel biofilm carrier, polyurethane foam filler, due to its excellent porosity and mechanical properties, not only promotes microbial attachment and biofilm formation, but also intercepts suspended solids and improves gas-water distribution, thereby enhancing wastewater treatment effectiveness. The present invention adds liquefied starch alcohol to increase the filler's hydroxyl content, significantly enhancing its hydrophilic properties. It also possesses the biodegradability of bioaccumulation fillers, making it an environmentally friendly, clean filler.

[0024] 2. Among the many microbial denitrification methods, Anammox technology, as an emerging and highly efficient denitrification technology, not only offers high denitrification efficiency and no secondary pollution, but also reduces operating costs. It is of great significance for treating high-ammonia nitrogen wastewater and alleviating water eutrophication. Introducing an appropriate amount of iron minerals into the anaerobic ammonium oxidation (ANAMMOX) denitrification system not only helps to promote the enrichment of ANAMMOX and iron-reducing bacteria, increasing the abundance of functional genes and related enzyme activities, but also potentially improves sludge properties and enhances the stability of the ANAMMOX system by affecting sludge concentration, heme C content, extracellular polymer content, and granulation. Therefore, to achieve higher denitrification rates and ANAMMOX specific activity, the present invention combines iron powder with a hydrophilic filler to prepare a modified polyurethane foam filler. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a sample picture of the hydrophilic nano-iron-rich polyurethane bioaccumulation filler prepared in Example 1 after biofilm formation;

[0026] Figure 2 This is a sample picture of the hydrophilic nano-iron-rich polyurethane bioaccumulation filler prepared in Example 2 after biofilm formation. DETAILED DESCRIPTION

[0027] The present invention provides a highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler, which is prepared by including the following components in parts by mass: 50-70 parts of liquefied starch alcohol, component A, component B, and 0.2-0.3 parts of nano-iron powder;

[0028] Component A comprises: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst;

[0029] Component B includes: 123-125 parts of isocyanate and 0.1-0.3 parts of catalyst.

[0030] In the present invention, the method for preparing liquefied starch alcohol preferably comprises: mixing a liquefying agent, a catalyst, and starch, and conducting a liquefaction reaction to obtain liquefied starch alcohol. Specifically, the liquefying agent, the catalyst, and the starch are mixed, heated and liquefied while stirring, and the temperature change is monitored until the liquefaction reaction is completed to obtain a yellowish-brown transparent liquid.

[0031] In the present invention, the liquefier preferably includes glycerol and polyethylene glycol, and the mass ratio of the glycerol to polyethylene glycol is preferably 4:6 to 3:7.

[0032] In the present invention, the catalyst is preferably a sulfuric acid solution, and the concentration of the sulfuric acid solution is preferably 4% to 8% wt.

[0033] In the present invention, the starch is preferably corn starch, tapioca starch, soluble starch, or potato starch; and the mass of the starch is preferably 13 to 17 g.

[0034] In the present invention, the heating temperature of the liquefaction reaction is preferably 140-180° C., the stirring speed is preferably 100-120 rm, and the time is preferably 1-2 h.

[0035] In the present invention, the particle size of the nano iron powder is preferably 50-100 nm, and the amount of the nano iron powder added is preferably 0.25-1.25 g. The present invention also provides a method for preparing the highly hydrophilic nano iron-rich polyurethane bioaccumulator filler, comprising the following steps:

[0036] 1) mixing liquefied starch alcohol, component A, and nano iron powder to obtain a first mixed solution;

[0037] 2) mixing the first mixed solution obtained in step 1) with component B to obtain a second mixed solution;

[0038] 3) The second mixed solution obtained in step 2) is foamed and cured at high temperature to obtain a highly hydrophilic nano-iron-rich polyurethane bio-enriched filler.

[0039] In the present invention, the component A preferably includes: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst.

[0040] In the present invention, the polyether polyol is preferably 3010 or 330N; the gel catalyst is preferably a 33% triethylenediamine solution; the foaming agent is preferably water; and the foam stabilizer is preferably L-580, G-580, or W-5903.

[0041] In the present invention, the B component preferably includes: 123 to 125 parts of isocyanate and 0.1 to 0.3 parts of catalyst.

[0042] In the present invention, the isocyanate preferably includes TDI-80 and TDI-100; the catalyst preferably includes dibutyltin dilaurate DBTDL and stannous octoate T-9.

[0043] In the present invention, the amount of the polyether polyol added is preferably 130~150g, more preferably 140~150g; the amount of the liquefied starch alcohol added is preferably 52~70g; the amount of the gel catalyst added is preferably 0.1~0.2g, more preferably 0.2g; the amount of the foaming agent added is preferably 5~10ml, more preferably 9ml; the amount of the foam stabilizer added is preferably 0.65~0.8g, more preferably 0.75g; the amount of the isocyanate added is preferably 115~124g, more preferably 119g; and the amount of the catalyst added is preferably 0.075~0.200g.

[0044] In the present invention, the method for mixing the first mixed solution and component B is preferably stirring, the stirring speed is preferably 1000-1500 rm, more preferably 1200 rm, and the stirring time is preferably 5-10 s.

[0045] In the present invention, the low-temperature foaming temperature is preferably 20-25° C., more preferably 23° C.; the low-temperature foaming time is preferably 20-40 min, more preferably 25 min.

[0046] In the present invention, the temperature for high-temperature curing is preferably 150-200°C; the time for high-temperature curing is preferably 1-2 hours. In the present invention, the method for preparing the highly hydrophilic nano-iron-rich polyurethane bioaccumulator preferably includes the following steps: first, preparing liquefied starch alcohol; mixing a liquefying agent with a catalyst and starch; heating and liquefying the mixture while stirring; monitoring the temperature change until the liquefaction reaction is completed to obtain a yellow-brown transparent liquid; after the liquefied starch alcohol is cooled, mixing it with prefabricated liquid A to obtain a primary mixed liquid; performing a secondary mixing of the prefabricated liquid A (component A) and liquid B (component B); and stirring the mixture at high speed to obtain a third mixed liquid. The third mixed liquid is rapidly transferred to a low-temperature foaming chamber for foaming; and after the foaming is completed, high-temperature curing is performed to obtain a highly hydrophilic nano-iron-rich polyurethane clean foam filler.

[0047] In the present invention, hydrophilic property is usually relevant with the polar functional group on molecular surface, and these functional groups can form stronger hydrogen bond with water molecule, thus increase the hydrophilicity of molecule.Because liquefied starch alcohol is generated by starch by esterification reaction and alcohols substance reaction, hydrophilic group wherein may include functional groups such as hydroxyl (-OH) and / or carboxyl (-COOH), because these functional groups have higher polarity, can form hydrogen bond with water molecule, therefore, select it to replace a part of polyether polyol as the raw material of prefabricated A liquid and can increase hydrophilicity.Selecting mixed nano iron powder to add in prefabricated A liquid can make it be evenly distributed in whole component inside, nano iron powder and ordinary iron powder have lightweight and easy dispersibility, make iron powder also can be more easily attached to the network structure of foam after A liquid and B liquid mixed foaming, realize specific modification.When adopting high-speed stirring to make the first mixing and the second mixing before foaming, can also uniform bubble prevent bubble size from being different, promote the formation of polymer / gas homogeneous system, promote cell nucleation to grow and shape. The present invention also provides the use of the highly hydrophilic nano-iron-rich polyurethane bio-enrichment filler in sewage treatment.

[0048] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention. Example 1

[0049] Raw material preparation: pure water, analytical grade polyethylene glycol, analytical grade glycerol, analytical grade concentrated sulfuric acid, analytical grade soluble starch, purchase commercial brand 3010 polyether polyol, brand T-9 stannous octoate catalyst, brand A-33 commercial triethylenediamine catalyst, brand W5903 foam stabilizer, brand TDI-80 isocyanate.

[0050] Preparation of liquefied starch: First, place 100 parts of the liquefaction solvent (polyethylene glycol and glycerol, 7:3) and 3 parts of the catalyst (5 wt% concentrated sulfuric acid) in a flask and preheat the oil bath to 100°C. Then, add 17 parts of starch to the flask and mix thoroughly with the liquefaction chemicals. Add the starch in batches and continue heating to 150°C for 4 hours, stirring continuously under atmospheric pressure to liquefy. After the predetermined reaction time, turn off the heater and continue stirring until the mixture cools.

[0051] Ingredients: By weight, pour 60 parts of liquefied starch alcohol into measuring cup A, add 140 parts of 3010 polyether polyol and 9 parts of pure water, and stir briefly. Use a syringe to draw 0.8 parts of foam stabilizer W5903 and add it. Add 124 parts of isocyanate raw material TDI-80 to measuring cup B. Determine by titration and gravimetric method the amount of 0.2 parts of gel catalyst A33 (25 drops) and 0.2 parts of catalyst T-9 (28 drops). Add these to measuring cups A and B, respectively, and gently stir until evenly combined.

[0052] Material Mixing and Foaming: Weigh 0.25 parts by mass of nano-iron powder into measuring cup A and stir thoroughly. Quickly pour the liquid from measuring cup B into measuring cup A. Stir using an industrial mechanical stirring arm at a speed of 1500 rpm and a stirring time of 8 seconds. Quickly pour the material into the foaming box and transfer it to the low-temperature foaming chamber, adjusting the temperature to 23°C.

[0053] Curing: After the foam cools down, it is demoulded and sent into the oven for high temperature curing, and the temperature is adjusted to 150℃.

[0054] Foam cutting: Take the foam out of the foaming box, peel it and cut it into 20mm×20mm×20mm squares. The foam porosity after cutting is greater than 95% and the bulk density is 0.047g / cm 3 Place it in running water and immerse it completely in water after 5 seconds. A stirred or flowing water environment is conducive to faster infiltration of the reticulated foam. Nano-iron powder can be seen on the surface, with a coverage of more than 70%.

[0055] Example 2

[0056] Raw material preparation: pure water, analytical grade polyethylene glycol, analytical grade glycerol, analytical grade concentrated sulfuric acid, analytical grade soluble starch, purchase commercial brand 3010 polyether polyol, brand T-9 stannous octoate catalyst, brand A-33 commercial triethylenediamine catalyst, brand W580 foam stabilizer, brand TDI-80 isocyanate.

[0057] Preparation of liquefied starch: First, place 100 parts of the liquefaction solvent (polyethylene glycol and glycerol, 7:3) and 3 parts of the catalyst (5 wt% concentrated sulfuric acid) in a flask and preheat the oil bath to 100°C. Then, add 17 parts of starch to the flask and mix thoroughly with the liquefaction chemicals. Add the starch in batches and continue heating to 150°C for 4 hours, stirring continuously under atmospheric pressure to liquefy. After the predetermined reaction time, turn off the heater and continue stirring until the mixture cools.

[0058] Ingredients: By weight, pour 52 parts of liquefied starch alcohol into measuring cup A, add 148 parts of 3010 polyether polyol and 9 parts of pure water, and stir briefly. Use a syringe to draw 0.8 parts of foam stabilizer W580 and add it. Add 124 parts of isocyanate raw material TDI-80 to measuring cup B. Determine by titration and gravimetric method the amount of 0.2 parts of gel catalyst A33 (25 drops) and 0.2 parts of catalyst T-9 (28 drops). Add these to measuring cups A and B, respectively, and gently stir until evenly combined.

[0059] Material Mixing and Foaming: Weigh 0.15 parts by mass of nano-iron powder into measuring cup A and stir thoroughly. Quickly pour the liquid from measuring cup B into measuring cup A. Stir using an industrial mechanical stirring arm at a speed of 1500 rpm and a stirring time of 8 seconds. Quickly pour the material into the foaming box and transfer it to the low-temperature foaming chamber, adjusting the temperature to 23°C.

[0060] Curing: After the foam cools down, it is demoulded and sent into the oven for high temperature curing, and the temperature is adjusted to 150℃.

[0061] Foam cutting: Take the foam out of the foaming box, peel it and cut it into 20mm×20mm×20mm squares. The foam porosity after cutting is greater than 90% and the bulk density is 0.035g / cm 3 Place it in running water and immerse it completely in water after 12 seconds. A stirred or flowing water environment is conducive to faster infiltration of the reticulated foam. Nano-iron powder can be seen on the surface, with a coverage of more than 60%.

[0062] Example 3

[0063] The hydrophilic, nano-iron-rich polyurethane bioaccumulator prepared in Examples 1 and 2 was cut into 20 mm x 20 mm x 20 mm blocks. The blocks were then placed in a 400 ml anaerobic bottle along with a commercially available hydrophilic sponge of the same volume. Anaerobic ammonia-oxidizing bacteria were inoculated and allowed to form biofilms. After biofilm formation, the biofilms were removed and placed in 100 ml dark-protected anaerobic bottles.

[0064] Simulated nitrogenous wastewater was introduced, wherein the simulated nitrogenous wastewater was prepared by sodium nitrite, potassium dihydrogen phosphate, potassium bicarbonate, ammonium chloride and tap water, wherein the nitrite nitrogen concentration in the simulated nitrogenous wastewater was 20 mg / L and the ammonia nitrogen concentration was 15 mg / L. The anaerobic bottle was placed in a shaking table, kept at a constant temperature of 30 degrees Celsius, and a rotation speed of 140 rm. After 15 days of film formation, the sample diagram is as follows. The foregoing is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler, characterized in that: The invention is prepared by comprising the following components in parts by weight: 50-70 parts of liquefied starch alcohol, component A, component B, and 0.2-0.3 parts of nano iron powder. The preparation method of the liquefied starch alcohol comprises: mixing a liquefying agent, a catalyst, and starch, and performing a liquefaction reaction to obtain liquefied starch alcohol; Wherein, component A comprises: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst, wherein the gel catalyst comprises triethylenediamine solution; Component B includes: 123-125 parts of isocyanate and 0.1-0.3 parts of catalyst, wherein the catalyst includes dibutyltin dilaurate and stannous octoate.

2. A highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler according to claim 1, characterized in that: The liquefier comprises glycerol and polyethylene glycol, and the mass ratio of the glycerol to the polyethylene glycol is 4:6 to 3:

7.

3. A highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler according to claim 1, characterized in that: The foam stabilizers in the A component include L-580, G-580, and W-5903.

4. A highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler according to claim 1, characterized in that: The foaming agent in the A component includes water.

5. The method for preparing a highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler according to claim 1, characterized in that: The following steps are involved: 1) mixing liquefied starch alcohol, component A and nano iron powder to obtain a first mixed solution; 2) mixing the first mixed solution obtained in step 1) with component B to obtain a second mixed solution; 3) The second mixed solution obtained in step 2) is foamed and cured at high temperature to obtain a highly hydrophilic nano-iron-rich polyurethane bio-enriched filler.

6. The method for preparing a highly hydrophilic nano-iron-rich polyurethane bioaccumulator filler according to claim 5, characterized in that: In the step 3), the foaming temperature is 20-25° C., and the foaming time is 20-40 minutes; the high-temperature curing temperature is 150-200° C., and the high-temperature curing time is 1-2 hours.

7. Use of the highly hydrophilic nano-iron-rich polyurethane bioaccumulation filler according to claim 1 in sewage treatment.

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