Renewable oil-water separation material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oil-water separation, in particular to a renewable oil-water separation material as well as a preparation method and application thereof. According to the preparation method, a melamine foam material is soaked in a mixed solution composed of cane sugar, dopamine and a trihydroxymethyl aminomethane-hydrochloric acid buffer solution, and the renewable oil-water separation material is obtained; the renewable oil-water separation material can quickly and efficiently separate different types of oily wastewater such as kitchen oil, industrial oil and organic solvents, the separation efficiency can reach 99% or above, and the separation flux can reach 104-105 liters per square meter per hour. Moreover, the used renewable oil-water separation material can be repeatedly used after being fully soaked in an ethanol solution, and the separation flux and the separation efficiency are not obviously reduced. In addition, the renewable oil-water separation material has a wide oil-water separation effect and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-water separation, and particularly relates to a renewable oil-water separation material, a preparation method thereof, and an application thereof. Background Art

[0002] In the field of oil-water separation technology, the membrane separation method is widely used due to its advantages such as simple operation, high efficiency, and low energy consumption. Among them, superhydrophilic membrane materials can quickly permeate water molecules and form a hydration layer, reducing the adsorption of oils and organic solvents, and showing excellent anti-pollution and self-cleaning capabilities.

[0003] However, existing superhydrophilic membrane materials still face many challenges in achieving long-term and efficient oil-water separation. For example, after multiple oil-water separations, their surfaces are easily covered by oil stains, resulting in an irreversible decrease in flux and gradually losing the separation function. Summary of the Invention

[0004] In order to better perform oil-water separation, the present invention provides a renewable oil-water separation material, a preparation method thereof, and an application thereof.

[0005] The first aspect of the present invention provides a preparation method of a renewable oil-water separation material, which includes the following steps: Mix sucrose, dopamine, and tris(hydroxymethyl)aminomethane-hydrochloride buffer solution (Tris-HCl buffer solution) to obtain a mixed solution; Immerse the melamine foam material in the mixed solution to obtain a renewable oil-water separation material.

[0006] Among them, the melamine foam material is a support material, which self-assembles in the tris(hydroxymethyl)aminomethane-hydrochloride buffer solution containing sucrose and dopamine, thereby forming a renewable oil-water separation material with a surface coated with polydopamine. This renewable oil-water separation material can be repeatedly used for oil-water separation.

[0007] In an implementable embodiment, the mass concentration of sucrose in the mixed solution is 0.15% - 1%.

[0008] In an implementable embodiment, the mass concentration of dopamine in the mixed solution is 1% - 5%.

[0009] In an implementable embodiment, the concentration of the tris(hydroxymethyl)aminomethane-hydrochloride buffer solution is 0.1 - 0.2 M.

[0010] In one embodiment, when the concentration of the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 0.1 M, the concentration of sucrose in the mixed solution is 0.0015 - 0.01 g / mL, and the concentration of dopamine in the mixed solution is 0.01 - 0.05 g / mL. Preferably, when the concentration of the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 0.1 M, the concentration of sucrose in the mixed solution is 0.0015 g / mL, and the concentration of dopamine in the mixed solution is 0.01 g / mL.

[0011] In one embodiment, the pH of the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 7 - 10. Preferably, the pH of the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 8.

[0012] In one embodiment, when the melamine foam material is immersed in the mixed solution, the temperature of the mixed solution is 30 - 60 °C, and the immersion time is 4 - 24 h. Preferably, when the melamine foam material is immersed in the mixed solution, the temperature of the mixed solution is 45 °C, and the immersion time is 12 h.

[0013] In one embodiment, before immersing the melamine foam material in the mixed solution, it further includes the step of cleaning the melamine foam material with an ethanol solution.

[0014] The second aspect of the present invention provides a renewable oil-water separation material, which is obtained by the preparation method of the above-mentioned renewable oil-water separation material.

[0015] The third aspect of the present invention provides the application of the above-mentioned renewable oil-water separation material in oil-water separation.

[0016] The fourth aspect of the present invention provides an oil-water separation method, which includes the following steps: Placing the oil-water mixture on one side of the above-mentioned renewable oil-water separation material; Making the water in the oil-water mixture pass through the above-mentioned renewable oil-water separation material under the action of a driving force.

[0017] In one embodiment, the oil in the oil-water mixture is one or more of n-hexane, benzoic acid, petroleum ether, petroleum crude oil, refrigeration oil, paraffin oil, corn oil, soybean oil, and olive oil.

[0018] In the present invention, the melamine foam material is immersed in a mixed solution composed of sucrose, dopamine, and tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution to obtain a renewable oil-water separation material; this renewable oil-water separation material can quickly and efficiently separate different types of oily wastewater such as kitchen oil, industrial oil, and organic solvents, and its separation efficiency can reach more than 99%, and the separation flux can reach 10 4 -10 5L per square meter per hour. Moreover, the used renewable oil-water separation material can be reused after being fully soaked in an ethanol solution, and the separation flux and separation efficiency do not decrease significantly. In addition, the renewable oil-water separation material has a wide range of oil-water separation effects and is suitable for industrial production. Description of the Drawings

[0019] Figure 1 Scanning electron microscope photograph of the surface of the melamine foam material after removing impurities for Comparative Example 1.

[0020] Figure 2 Scanning electron microscope photograph of the surface of the polydopamine-coated melamine material for Comparative Example 2.

[0021] Figure 3 Scanning electron microscope photograph of the surface of the renewable oil-water separation material of Example 1 of the present invention.

[0022] Figure 4 Photograph of the underwater oil contact angle and contact angle data diagram of the materials in Comparative Example 2 and Example 1 of the present invention.

[0023] Figure 5 Photograph of the renewable oil-water separation material of Example 1 of the present invention in contact with water droplets.

[0024] Figure 6 Photograph of the renewable oil-water separation material of Example 1 of the present invention in contact with oil droplets underwater.

[0025] Figure 7 Contact angle data diagram of the renewable oil-water separation materials of Examples 1-5 of the present invention.

[0026] Figure 8 Contact angle data diagram of the renewable oil-water separation materials of Examples 1, 6-8 of the present invention.

[0027] Figure 9 Contact angle data diagram of the renewable oil-water separation materials of Examples 1, 9-11 of the present invention.

[0028] Figure 10 Contact angle data diagram of the renewable oil-water separation materials of Examples 1, 12, 13 of the present invention.

[0029] Figure 11 Photograph of the physical object of the oil-water separator used in the examples of the present invention.

[0030] Figure 12 Photograph of the oil-water separation process of Example 14 of the present invention.

[0031] Figure 13 Oil-water separation result diagram of Examples 14-22 of the present invention.

[0032] Figure 14 This is the oil-water separation result diagram of Example 14, Examples 23 - 27 of the present invention.

[0033] Figure 15 This is the oil-water separation result diagram of Examples 28 - 30 of the present invention.

[0034] Figure 16 This is the oil-water separation result diagram of Examples 31 - 33 of the present invention. Detailed implementation manners

[0035] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0036] Example 1:

[0037] Cut the melamine foam material into cuboid small pieces with dimensions of 1.5 cm × 1.0 cm × 0.5 cm, and ultrasonically treat it in an ethanol solution with a concentration of 75% for 20 min to obtain the cleaned melamine foam; dissolve 0.09 g of sucrose and 0.6 g of dopamine in 60 mL of a 0.1 M tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution, and adjust the pH to 8 to obtain a mixed solution; immerse the cleaned melamine foam in the mixed solution for 12 hours, and keep the temperature at 45 °C during the immersion to obtain a renewable oil-water separation material.

[0038] Comparative Example 1:

[0039] Cut the melamine foam material into cuboid small pieces with dimensions of 1.5 cm × 1.0 cm × 0.5 cm, and ultrasonically treat it in an ethanol solution with a concentration of 75% for 20 min to obtain the cleaned melamine foam.

[0040] Comparative Example 2:

[0041] Cut the melamine foam material into cuboid small pieces with dimensions of 1.5 cm × 1.0 cm × 0.5 cm, and ultrasonically treat it in an ethanol solution with a concentration of 75% for 20 min to obtain the cleaned melamine foam; dissolve 0.6 g of dopamine in 60 mL of a 0.1 M tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution, and adjust the pH to 8 to obtain a mixed solution; immerse the cleaned melamine foam in the mixed solution for 12 hours, and keep the temperature at 45 °C during the immersion to obtain a melamine material coated with polydopamine.

[0042] The surface analysis of the materials obtained in Comparative Example 1, Comparative Example 2 and Example 1 was carried out using a scanning electron microscope (SEM). As Figure 1 shown, the surface of the melamine foam after cleaning in Comparative Example 1 was relatively smooth overall; as Figure 2 shown, after loading polydopamine on the support material, there were a large number of granular protrusion structures on the surface of the polydopamine-coated melamine material in Comparative Example 2; as Figure 3 shown, in addition to a large number of granular protrusion structures on the surface of the melamine foam material in Example 1, a thin film also covered most of the pores.

[0043] The contact angle tests were carried out on the materials obtained in Comparative Example 2 and Example 1. The results were as Figure 4 shown. After the uniform loading of polydopamine on the surface of the melamine foam material, regardless of whether sucrose was contained or not, the underwater oil contact angle was 155°, indicating that both the polydopamine-coated melamine material in Comparative Example 2 and the renewable oil-water separation material in Example 1 were underwater superoleophobic structures.

[0044] The hydrophilicity test was carried out on the renewable oil-water separation material of Example 1. As the water droplet was gradually brought closer to the surface of the material, during the process of dripping the water droplet onto the surface of the material with a syringe needle, the water droplet was quickly adsorbed by the surface of the material and spread out (see Figure 5 ). When the material was placed underwater and the oil droplet was dripped onto the surface of the material with a syringe needle, and then the syringe needle was lifted, during the lifting process, the oil droplet would be desorbed together with the syringe needle (see Figure 6 ), and no oil droplet remained on the surface of the material, nor was there an obvious surface adsorption phenomenon. This indicated that the renewable oil-water separation material of Example 1 had superhydrophilic and underwater superoleophobic properties.

[0045] Examples 2-5:

[0046] On the basis of Example 1, without changing other conditions, a series of renewable oil-water separation materials were obtained only by changing the concentration of sucrose, and their specific parameters are shown in Table 1.

[0047] Table 1 Parameters of different sucrose concentrations

[0048] The underwater oil contact angle tests were respectively carried out on the renewable oil-water separation materials of Examples 2-5. The results were as Figure 7 shown. As the amount of sucrose used increased, the contact angle decreased slightly, indicating that the hydrophilicity decreased with the increase in the sucrose content.

[0049] Examples 6-8:

[0050] Based on Example 1, a series of renewable oil-water separation materials were obtained by only changing the concentration of dopamine, and the specific parameters are shown in Table 2.

[0051] Table 2 Parameters of different dopamine concentrations

[0052] The underwater oil contact angles of the renewable oil-water separation materials in Examples 6 - 8 were tested respectively, and the results are shown in Figure 8 , and it can be seen from the figure that the increase in dopamine content has little effect on the contact angle.

[0053] Examples 9 - 11:

[0054] Based on Example 1, a series of renewable oil-water separation materials were obtained by only changing the pH value of the mixed solution, and the specific parameters are shown in Table 3.

[0055] Table 3 Parameters of different pH values

[0056] The underwater oil contact angles of the renewable oil-water separation materials in Examples 9 - 11 were tested respectively, and the results are as shown in Figure 9 . It can be seen from the contact angle data that when the pH increases from 7 to 10, the contact angle first increases and then decreases; when the pH is 8, the contact angle is the largest, indicating that the hydrophilicity is the best at this time.

[0057] Examples 12 - 13:

[0058] Based on Example 1, a series of renewable oil-water separation materials were obtained by only changing the soaking temperature of the melamine foam after cleaning in the mixed solution, and the specific parameters are shown in Table 4.

[0059] Table 4 Parameters of different temperatures

[0060] The underwater oil contact angles of the renewable oil-water separation materials in Example 12 and Example 13 were tested, and the results are as shown in Figure 10 . It can be seen from the contact angle data that when reacting at 30 °C and 45 °C, the contact angle changes little; but when the reaction temperature rises to 60 °C, the contact angle decreases, indicating that the hydrophilicity of the material decreases at high temperatures.

[0061] Examples 14 - 22:

[0062] Petroleum ether was dyed red with Sudan dye solution and then mixed with water in a ratio of 1:9 to obtain an oil-water mixture; the renewable oil-water separation material prepared by the same method as in Example 1 was used as a separation membrane and installed on the separator, where the structure of the separator is as shown in Figure 11As shown; 100 mL of the oil-water mixture was poured into the upper end of the separator for the oil-water separation experiment, and the separation process was as Figure 12 shown.

[0063] By only changing the types of oil for the oil-water separation experiment, a series of data on different separation fluxes and separation efficiencies can be obtained, and the specific parameters are shown in Table 5.

[0064] Table 5 Specific parameters of different oil-water mixtures

[0065] The oil-water separation experiments of Examples 14 - 22 were repeated 10 times, and the average separation flux and separation efficiency were calculated. The results are as Figure 13 shown. The results show that the separation fluxes of all oils are between 5.0×10 4 -1.3×10 5 L / (m²·h). When separating the n-hexane / water mixture, the maximum flux of water can reach 1.2×10 5 L / (m²·h). The average separation flux of crude petroleum also reaches 9.3×10 4 L / (m²·h). For refrigeration oil and edible oils with higher viscosities (such as corn oil, soybean oil, olive oil), their average separation fluxes are all higher than 6.0×10 4 L / (m²·h). In addition, the average separation efficiency of all materials after 10 separations is higher than 99.2%, and the separation efficiency of most oils fluctuates very little. This shows that the renewable oil-water separation material prepared by the method of Example 1 has a wide range of oil-water separation capabilities.

[0066] Examples 23 - 27:

[0067] On the basis of Example 14, by only changing the number of separations for the oil-water separation experiment, a series of data on different separation fluxes and separation efficiencies can be obtained, and the specific parameters are shown in Table 6.

[0068] Table 6 Specific parameters of different separation times for petroleum ether / water mixture

[0069] After every 10 separations, the average separation flux and separation efficiency were statistically analyzed. The results are as Figure 14 shown. As the number of separations increases, the separation flux decreases from 7.5×10 4 L / (m²·h) to 5.1×10 4 L / (m²·h). The separation efficiency also shows a downward trend with the increase in the number of separations, but the separation efficiency is higher than 99.5%. This is related to the fact that the surface of the renewable oil-water separation material is contaminated by oil as the number of separations increases.

[0070] Examples 28 - 30:

[0071] Based on Example 14, after every 10 repetitions of the oil - water separation experiment, the renewable oil - water separation material was completely immersed in an ethanol solution with a concentration of 75% for 30 min (i.e., the renewable oil - water separation material was cleaned with the ethanol solution), and then 10 oil - water separation experiments were repeated. By changing the number of cleaning times, a series of data on different separation fluxes and separation efficiencies can be obtained, and the specific parameters are shown in Table 7.

[0072] Table 7 Specific parameters of ethanol solution cleaning after oil - water separation of petroleum ether / water mixture

[0073] After each cleaning with the ethanol solution, 10 oil - water separation experiments were carried out, and then the separation flux and separation efficiency were calculated. The results are as Figure 15 shown, indicating that after 10 separations, cleaning with the ethanol solution can effectively remove the oil stains on the surface of the renewable oil - water separation material, and the separation flux and separation efficiency of the renewable oil - water separation material can be effectively maintained, proving the renewable characteristics of the renewable oil - water separation material.

[0074] Examples 31 - 33:

[0075] Based on Example 20, after every 10 repetitions of the oil - water separation experiment, the renewable oil - water separation material was completely immersed in an ethanol solution with a concentration of 75% for 30 min (i.e., the renewable oil - water separation material was cleaned with the ethanol solution), and then 10 oil - water separation experiments were repeated. By changing the number of cleaning times, a series of data on different separation fluxes and separation efficiencies can be obtained, and the specific parameters are shown in Table 8.

[0076] Table 8 Specific parameters of ethanol solution cleaning after oil - water separation of corn oil / water mixture

[0077] After each cleaning with the ethanol solution, oil - water separation was carried out 10 times, and then the separation flux and separation efficiency were calculated. The results are as Figure 16 shown. It can be seen that after cleaning the renewable oil - water separation material with the ethanol solution and then carrying out oil - water separation, repeating this three times, the separation flux slightly decreased from 6.2×10 4 L / (m²·h) to 5.5×10 4 L / (m²·h), while the separation efficiency remained basically unchanged. This shows that the renewable oil - water separation material has good regeneration ability and can be repeatedly used for oil - water separation.

[0078] In the above embodiments, the water flux during the oil-water separation process is calculated using formula (1), and the oil-water separation efficiency during the oil-water separation process is calculated using formula (2).

[0079]

[0080] Among them, V represents the volume of water passing through the separator, with the unit of liters; S represents the effective cross-sectional area of the oil-water separation material during the separation process, with the unit of square meters; t represents the time of oil-water separation, with the unit of hours.

[0081]

[0082] Among them, C f represents the weight of the oil after separation, C 0 represents the weight of the oil before separation.

[0083] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a renewable oil-water separation material, characterized in that, It includes the following steps: Mix sucrose, dopamine and tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution to obtain a mixed solution; Soak the melamine foam material in the mixed solution to obtain a renewable oil-water separation material.

2. The method according to claim 1, wherein The mass concentration of sucrose in the mixed solution is 0.15%-1%.

3. The method according to claim 1, wherein The mass concentration of dopamine in the mixed solution is 1%-5%.

4. The method according to claim 1, wherein The concentration of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 0.1-0.2M.

5. The method according to claim 1, wherein The pH of the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution is 7-10.

6. The method according to claim 1, characterized in that, When the melamine foam material is soaked in the mixed solution, the temperature of the mixed solution is 30-60°C and the soaking time is 4-24h.

7. A renewable oil-water separation material, characterized in that, It is obtained by the preparation method of the renewable oil-water separation material according to any one of claims 1-6.

8. The application of the renewable oil-water separation material according to claim 7 in oil-water separation.

9. An oil-water separation method, characterized in that, It includes the following steps: Place the oil-water mixture on one side of the renewable oil-water separation material according to claim 7; Make the water in the oil-water mixture pass through the renewable oil-water separation material under the action of a driving force.

10. The oil-water separation method according to claim 9, wherein The oil in the oil-water mixture is one or more of n-hexane, benzoic acid, petroleum ether, petroleum crude oil, refrigeration oil, paraffin oil, corn oil, soybean oil, olive oil.

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