CN116813076A - A kind of preparation method of modified polyurethane filler - Google Patents

Abstract

The invention relates to the technical field of polymer carrier modification, and in particular to a preparation method of modified polyurethane filler. In the present invention, a peroxide solution and a divalent iron salt solution are mixed, and the pH is adjusted to obtain a mixed solution; then the polyurethane filler is immersed in the mixed solution for modification, and finally a modified polyurethane filler is obtained. The novel polyurethane filler obtained through the modification method of the present invention has greatly improved bioaffinity. Compared with traditional polyurethane filler, it has a larger specific surface area and is effective in adsorbing and growing biofilms on the surface of the filler. The promotion effect can improve the efficiency of wastewater treatment in biofilm method.

Description

A kind of preparation method of modified polyurethane filler

Technical field

The invention relates to the technical field of polymer carrier modification, and in particular to a preparation method of modified polyurethane filler.

Background technique

Biofilm method is a water treatment technology that uses microorganisms growing on carrier materials for biological treatment of sewage. The main function of the carrier material is to provide a microenvironment for microorganisms to survive, which greatly improves the resistance of microorganisms to various pollutants. . Compared with other similar materials, polyurethane filler has a larger specific surface area and can achieve good separation from water while maintaining a sufficient number of bacteria. However, its immobilization of microorganisms is only achieved through physical adsorption, which causes the microbial cells to easily fall off. Therefore, it needs to be modified to increase its surface roughness and improve surface bioaffinity.

The current modification of fillers includes bulk modification and surface modification. Most bulk modifications of polyurethane fillers involve adding nanomaterials such as nano-SiO ₂ to the filler. Although it can improve the filler's affinity for microorganisms and physical and chemical stability, it is expensive and difficult to obtain, and has certain limitations in promotion. sex. Among surface modifications, mechanical modification is suitable for fillers with metal coatings. Surface roughening methods require processing of fillers in molds, and are not suitable for polyurethane fillers. Low-temperature plasma modification and high-energy radiation modification have low environmental pollution and short processing cycles. , but its application conditions are relatively harsh and not suitable for promotion. At present, the most widely used ones are liquid phase chemical oxidation method and surface grafting method. The latter mainly uses sodium alginate and gelatin protein for grafting. The material surface becomes rough after chemical oxidation. In many studies, ion covering or surface grafting is added after oxidation to enhance the modification effect. For example, potassium permanganate oxidation-iron ion covering modification and potassium permanganate oxidation-gelatin protein grafting modification are used. Studies have shown that gelatin protein grafting modification after oxidation is slightly better than Fe ³⁺ covering modification. Some, but the Fe3 ⁺ modification process is less expensive.

Therefore, how to provide a modification method that is light-pollution, more convenient and lower-cost to modify the bioaffinity of polyurethane fillers, which can accelerate the deposition of microorganisms on the surface of polyurethane fillers and enhance the stability of biofilms and fillers. It has become an urgent technical problem to be solved in this field.

Contents of the invention

The object of the present invention is to provide a preparation method of modified polyurethane filler to modify the bioaffinity of the polyurethane filler, thereby accelerating the deposition of microorganisms on the surface of the polyurethane filler and strengthening the stability of the biofilm and the filler, thereby solving the problem of Polyurethane filler biofilm takes a long time to hang and the biofilm is easy to fall off.

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

The invention provides a preparation method of modified polyurethane filler, which includes the following steps:

(1) Mix the peroxide solution and the ferrous iron salt solution, and adjust the pH to obtain a mixed solution;

(2) Immerse the polyurethane filler in the mixed solution for modification to obtain the modified polyurethane filler.

Preferably, in step (1), sodium hydroxide solution, hydrochloric acid solution or sulfuric acid solution is used to adjust the pH; the concentration of the sodium hydroxide solution is 0.1~0.5mol/L; the concentration of the hydrochloric acid solution is 0.1~0.5 mol/L; the concentration of the sulfuric acid solution is 0.1-0.5 mol/L; the pH of the mixed solution is ≤ 3.

Preferably, the concentration of peroxide in the mixed solution of step (1) is 0.1-10 mmol/L.

Preferably, the concentration of divalent iron salt in the mixed solution of step (1) is 0.1-10 mmol/L.

Preferably, the peroxide solution in step (1) includes hydrogen peroxide solution, peracetic acid solution or sodium persulfate solution.

Preferably, the ferrous iron salt solution in step (1) contains one or more of ferrous sulfate solution and ferrous chloride solution.

Preferably, the modification temperature in step (2) is 15 to 25°C, and the modification time is 1 to 4 hours.

Preferably, drying is performed after the modification in step (2) is completed to obtain the modified polyurethane filler; the drying temperature is 100-120°C and the time is 40-60 minutes.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention provides a method for modifying polyurethane fillers by using hydroxyl radicals and iron ions generated during an advanced oxidation reaction using divalent iron ions as catalysts and peroxides as oxidants, which are suitable for aquatic biological treatment. This method is characterized by light pollution, convenience, fast reaction, and good modification effect.

The method provided by the invention by modifying the surface structure of the polyurethane filler utilizes the hydroxyl radicals generated during the advanced oxidation reaction to oxidize the filler surface to increase the filler surface roughness and increase the specific surface area of the filler; due to the microbial cell membrane surface It has multiple negative charges and uses the iron ions produced by the reaction to modify the surface of the filler to change the potential of the filler surface, improve the bioaffinity of the filler, and is beneficial to the enrichment and immobilization of microorganisms.

The polyurethane filler prepared by the modification method of the present invention has a larger specific surface area than the traditional polyurethane filler, and can promote the adsorption and growth of microorganisms on the surface of the filler to form biofilms, and can be used in biofilm methods. , can improve the efficiency of wastewater treatment.

Description of the drawings

Figure 1 is a graph showing changes in biofilm loading with time before and after modification of the polyurethane filler in Example 1 of the present invention;

Figure 2 is a graph showing changes in ammonia nitrogen removal rate over time before and after modification of the polyurethane filler in Example 1 of the present invention;

Figure 3 is a graph showing the COD removal rate changing with time before and after modification of the polyurethane filler in Example 1 of the present invention.

Detailed ways

The invention provides a preparation method of modified polyurethane filler, which includes the following steps:

(1) Mix the peroxide solution and the ferrous iron salt solution, and adjust the pH to obtain a mixed solution;

(2) Immerse the polyurethane filler in the mixed solution for modification to obtain the modified polyurethane filler.

In the present invention, in the step (1), a sodium hydroxide solution, a hydrochloric acid solution or a sulfuric acid solution is used to adjust the pH, preferably a hydrochloric acid solution or a sulfuric acid solution is used to adjust the pH;

The concentration of the sodium hydroxide solution is 0.1~0.5mol/L, preferably 0.2~0.4mol/L, and further preferably 0.25~0.35mol/L; the concentration of the hydrochloric acid solution is 0.1~0.5mol/L, preferably 0.2 ~0.4mol/L, more preferably 0.25~0.35mol/L; the concentration of the sulfuric acid solution is 0.1~0.5mol/L, preferably 0.2~0.4mol/L, further preferably 0.25~0.35mol/L;

The pH of the mixed solution is ≤ 3, preferably pH ≤ 2.5, more preferably pH ≤ 2, and even more preferably pH ≤ 1.5.

In the present invention, the concentration of peroxide in the mixed solution of step (1) is 0.1~10mmol/L, preferably 1~8mmol/L, more preferably 2~6mmol/L, even more preferably 4~ 5mmol/L.

In the present invention, the concentration of divalent iron salt in the mixed solution of step (1) is 0.1 to 10 mmol/L, preferably 1 to 8 mmol/L, more preferably 2 to 6 mmol/L, and even more preferably 4 ~5mmol/L.

In the present invention, the concentration of the peroxide solution and the ferrous iron ion in the mixed solution described in step (1) are equal.

In the present invention, the peroxide solution in step (1) includes hydrogen peroxide solution, peracetic acid solution or sodium persulfate solution, preferably hydrogen peroxide solution or peracetic acid solution, and further preferably peracetic acid. solution.

In the present invention, the ferrous iron salt solution in step (1) includes one or more of ferrous sulfate solution and ferrous chloride solution, preferably ferrous sulfate solution.

In the present invention, the modification temperature in step (2) is 15-25°C, preferably 16-24°C, more preferably 18-22°C, even more preferably 20°C; the time is 1-4h, Preferably it is 1.5-3.5h, More preferably, it is 2-3h, Even more preferably, it is 2.5h.

In the present invention, drying is performed after the modification in step (2) is completed to obtain the modified polyurethane filler; the drying temperature is 100 to 120°C, preferably 102 to 115°C, and further preferably 105 to 110°C. ; The time is 40 to 60 minutes, preferably 45 to 55°C, more preferably 48 to 53°C, even more preferably 50°C.

The technical solutions provided by the present invention will be described in detail below with reference to the examples, but they should not be understood as limiting the protection scope of the present invention.

Example 1

Mix peracetic acid solution and ferrous sulfate solution, and use H ₂ SO ₄ solution with a concentration of 0.1 mol/L to adjust the pH of the resulting mixed solution to 3. The concentration of peracetic acid in the mixed solution is 1.0 mmol/L and sulfuric acid. The concentration of ferrous iron is 1.0mmol/L; the polyurethane filler is completely immersed in the mixed solution at a temperature of 20°C, and the soaking time is 2 hours for modification; after the modification is completed, the filler is heated at 105°C Dry for 60 minutes to obtain modified polyurethane filler.

Example 2

Mix peracetic acid solution and ferrous sulfate solution, and use H ₂ SO ₄ solution with a concentration of 0.1 mol/L to adjust the pH of the resulting mixed solution to 3. The concentration of peracetic acid in the mixed solution is 0.1 mmol/L and sulfuric acid. The concentration of ferrous iron is 0.1mmol/L; the polyurethane filler is completely immersed in the mixed solution at a temperature of 20°C, and the soaking time is 1 hour for modification; after the modification is completed, the filler is heated at 105°C Dry for 60 minutes to obtain modified polyurethane filler.

Example 3

Mix peracetic acid solution and ferrous sulfate solution, and use H ₂ SO ₄ solution with a concentration of 0.1 mol/L to adjust the pH of the resulting mixed solution to 3. The concentration of peracetic acid in the mixed solution is 10 mmol/L, and the ferrous sulfate solution is 10 mmol/L. The concentration of iron is 10mmol/L; the polyurethane filler is completely immersed in the mixed solution at a temperature of 20°C, and the soaking time is 4 hours for modification; after the modification is completed, the filler is dried at a high temperature of 105°C After 60 minutes, the modified polyurethane filler was obtained.

test case

experimental method:

Use glucose as the carbon source and ammonium bicarbonate as the nitrogen source to artificially distribute water. The COD of the water distribution is 340 mg/L, and the ammonia nitrogen concentration is 22 mg/L. The modified filler prepared in Example 1 and the unmodified filler were respectively filled in two identical reactors (effective volume: 1L) at a filler/solution filling ratio (filler volume/solution volume) of 5%.

Film hanging stage: Inoculate equal amounts of sludge from the aeration tank of the sewage treatment plant respectively, aerate and mix evenly and let stand. The sludge will be discharged after 24 hours. At this time, the inoculation is completed. After re-adding the water distribution, aeration reaction is carried out, the dissolved oxygen is controlled to 6-8 mg/L, the water is changed every 24 hours, and the film-hanging stage ends after 3 days.

Sampling stage: After the film is completed, perform a filler wastewater performance test to control dissolved oxygen 6 to 8 mg/L. The operation cycle is 24 hours, including 23 hours of aeration, 50 minutes of standing, and 10 minutes of water change. When changing the water at the end of each operating cycle, the COD and ammonia nitrogen values of the effluent from the two reactors were measured, and the modified filler and unmodified filler were taken out to test the amount of biofilm.

Analytical method:

(1) Biofilm quantity test method: Put the removed film-bearing filler (filler weight W1, g) into a weighing bottle wrapped with tinfoil, place it in an oven at 105°C to dry for 60 minutes, and weigh after cooling ( W2, g), take out the filler, place it in 1mol/L NaOH solution, heat it in a water bath at 70°C for 1 hour, then treat it with 40Hz ultrasonic wave for 1 hour, wash it several times with water until the exfoliated biofilm is washed away, and then put the filler back Dry, cool, and weigh the weighing bottle (W3, g), and calculate (W2-W3)*1000/W1, which is the dry weight of the biofilm on unit mass of filler (mg/g).

(2) COD removal rate test method: Use the potassium dichromate method to measure COD in the inlet and outlet water. The COD removal rate divided by the inlet water COD is the COD removal rate.

(3) Ammonia nitrogen removal rate test method: Use Nessler's reagent photometry to measure the ammonia nitrogen in the inlet and outlet water. The ammonia nitrogen removal rate divided by the ammonia nitrogen in the inlet water is the ammonia nitrogen removal rate.

Table 1 Comparison of biological modulus, COD removal rate, and ammonia nitrogen removal rate within 6 days before and after polyurethane filler modification in Example 1

Comparative item Day 1 Day 2 3rd day Day 4 Day 5 Day 6 Modified filler biofilm amount (mg/g) 39.45 60.90 83.85 104.40 127.05 189.50 Unmodified filler biofilm amount (mg/g) 25.20 40.65 47.55 63.00 80.10 148.05 Modified filler COD removal rate (%) 53.96 56.64 60.97 67.84 81.21 86.19 Unmodified filler COD removal rate (%) 22.26 26.32 31.7 38.33 41.4 48.46 Ammonia nitrogen removal rate of modified filler (%) 52.42 55.91 61.64 69.33 73.42 84.8 Ammonia nitrogen removal rate of unmodified filler (%) 21.08 26.13 32.72 38.74 45.5 60.81

According to Figure 1 and Table 1 of the present invention, it can be seen that the biofilm amount and biofilm growth rate of the modified filler are higher than that of the unmodified filler. On the 6th day of measurement, the amount of biofilm per 1g of modified filler and unmodified filler 189.50mg and 148.05mg respectively; the average daily growth of biofilm per 1g of modified filler and unmodified filler was 31.6mg/d and 24.7mg/d respectively. The average daily growth of biofilm on modified filler increased. 28.0%, higher biofilm growth rate;

According to Figure 2 and Table 1 of the present invention, it can be seen that the ammonia nitrogen treatment effect of modified filler on wastewater is significantly better than that of unmodified filler. The ammonia nitrogen removal rate of modified filler reaches 84.8%, while the ammonia nitrogen removal rate of unmodified filler is only 60.81 %;

According to Figure 3 and Table 1 of the present invention, it can be seen that the COD treatment effect of modified filler on wastewater is significantly better than that of unmodified filler. The COD removal rate of modified filler reaches 86.19%, while the COD removal rate of unmodified filler is only 48.46 %;

The reason for the difference in the removal effect of COD and ammonia nitrogen in wastewater between the two fillers is not only the obvious difference in the amount of biofilm between the two shown in Figure 1, but also related to the fact that the surface of the modified filler is covered with Fe ₂ O ₃ , and its weak magnetic field effect can promote Microbial life activities, and it can also promote enzymatic reactions in cells to accelerate nutrients in cell water.

As can be seen from the above examples, the present invention provides a method for aquatic biological treatment that utilizes hydroxyl radicals and iron ions generated during an advanced oxidation reaction using divalent iron ions as catalysts and peroxides as oxidants to react with polyurethane. Modification method for modifying fillers. The new type of filler prepared by the modification method of the present invention has a larger specific surface area than traditional polyurethane fillers, and can promote the adsorption and growth of microorganisms on the surface of the filler to form biofilms, and can be used in biofilm methods. , can improve the efficiency of wastewater treatment.

The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (8)

1. The preparation method of the modified polyurethane filler is characterized by comprising the following steps:

(1) Mixing a peroxide solution and a ferrous salt solution, and adjusting the pH value to obtain a mixed solution;

(2) Immersing polyurethane filler into the mixed solution for modification to obtain modified polyurethane filler.

2. The method for producing a modified polyurethane filler according to claim 1, wherein the pH is adjusted using a sodium hydroxide solution, a hydrochloric acid solution or a sulfuric acid solution in the step (1); the concentration of the sodium hydroxide solution is 0.1-0.5 mol/L; the concentration of the hydrochloric acid solution is 0.1-0.5 mol/L; the concentration of the sulfuric acid solution is 0.1-0.5 mol/L; the pH value of the mixed solution is less than or equal to 3.

3. The method for producing a modified polyurethane filler according to claim 1 or 2, wherein the concentration of the peroxide in the mixed solution of step (1) is 0.1 to 10mmol/L.

4. The method for producing a modified polyurethane filler according to claim 3, wherein the concentration of the ferrous salt in the mixed solution of the step (1) is 0.1 to 10mmol/L.

5. The method for producing a modified polyurethane filler according to claim 1 or 4, wherein the peroxide solution in the step (1) comprises a hydrogen peroxide solution, a peracetic acid solution or a sodium persulfate solution.

6. The method for producing a modified polyurethane filler according to claim 5, wherein the ferrous salt solution in the step (1) contains one or more of a ferrous sulfate solution and a ferrous chloride solution.

7. The method for producing a modified polyurethane filler according to claim 1, 2, 4 or 6, wherein the modification in the step (2) is carried out at 15 to 25℃for 1 to 4 hours.

8. The method for preparing modified polyurethane filler according to claim 7, wherein the modified polyurethane filler is obtained by drying after the modification in the step (2); the drying temperature is 100-120 ℃ and the drying time is 40-60 min.