Environment-friendly nano CaCO3 / PDMS modified polyurethane sponge, preparation method and application

Abstract

The invention belongs to the technical field of environment-friendly materials and oil-water separation treatment, and discloses environment-friendly nano CaCO3 / PDMS modified polyurethane sponge and a preparation method and application thereof.The preparation method includes the steps that nano calcium carbonate modified by a silane coupling agent KH560 and a PDMS curing system are ultrasonically dispersed in a normal hexane solution, then polyurethane sponge pretreated by dopamine is soaked in the normal hexane solution, and the polyurethane sponge is obtained; and carrying out ultrasonic treatment and high-temperature curing to obtain the environment-friendly nano CaCO3 / PDMS modified polyurethane sponge. The preparation method is simple and efficient, the obtained modified sponge material still shows excellent hydrophobic performance on the premise that fluorine-containing compounds are completely abandoned, the water contact angle of the modified sponge material reaches up to 136 degrees, and the modified sponge material shows good cycle stability and environmental friendliness when being used for treating oil-containing produced water and organic solvent wastewater. The problems of toxicity and environmental pollution of a traditional fluorine-containing modifier are avoided.

Description

Technical Field

[0001] This invention belongs to the field of oil-water separation materials technology, and in particular to an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge, its preparation method and application. Background Technology

[0002] With the rapid development of the petroleum industry, the discharge of produced water from oil fields has continued to increase. Produced water typically contains large amounts of recalcitrant oil-based organic pollutants, posing a serious challenge to environmental protection and the sustainable use of water resources. While existing technologies for oil-water separation have achieved some success, they still have the following major shortcomings: Firstly, traditional oil-water separation materials often use fluorinated modifiers to improve their hydrophobic and oleophobic properties. However, these modifiers generally have problems such as high toxicity, significant environmental hazards, and high cost, which limits their practical application and makes it difficult to meet the needs of green environmental protection and sustainable economic development.

[0003] Secondly, existing oil-water separation technologies (such as physical adsorption, gravity separation, and membrane separation) do not perform well in terms of material adsorption capacity and recycling stability. In particular, when treating produced water with high oil content and complex composition, existing materials have limited adsorption capacity and are prone to performance degradation, affecting treatment effect and service life.

[0004] Third, in practical applications, traditional materials are prone to problems such as clogging, pollution accumulation, and material aging, which leads to reduced oil-water separation efficiency, increased maintenance costs, and difficulty in achieving long-term and efficient oil-water separation treatment.

[0005] In summary, due to the shortcomings of existing technologies in terms of environmental friendliness, performance, and stability, there is an urgent need to develop an oil-water separation material that combines high efficiency, environmental friendliness, and high cycle stability to meet the treatment requirements of complex produced water. This invention is proposed against this backdrop, aiming to overcome the aforementioned technical bottlenecks.

[0006] In recent years, sponge modification technology based on nanomaterials has gradually become a research hotspot. By modifying polyurethane (PU) sponges with nano-CaCO3 and polydimethylsiloxane (PDMS), a synergistic effect of "micro-nano rough structure-chemical bonding-hydrophobic modification" can be constructed, improving the oil-water separation efficiency and durability of the material. However, the green preparation process for such novel composite materials is still immature, and there are few reports on their application effects and environmental friendliness evaluation in actual produced water treatment.

[0007] Therefore, there is an urgent need to develop a green, environmentally friendly, efficient and stable method for preparing nano-CaCO3 / PDMS modified polyurethane sponge to solve the problems of environmental toxicity and insufficient performance of traditional materials, thereby promoting the advancement of efficient treatment technology for oilfield produced water.

[0008] A search revealed no patent publications that are identical or similar to the preparation method and materials described in this invention. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge, its preparation method, and its application.

[0010] The technical solution adopted by this invention to solve its technical problem is: A method for preparing an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge, wherein nano-calcium carbonate modified with silane coupling agent KH560 and a PDMS curing system are ultrasonically dispersed in a hexane solution, and then a polyurethane sponge pretreated with dopamine is immersed in the solution for 15-30 minutes to achieve uniform loading of nano-CaCO3, followed by high-temperature curing to obtain the environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge.

[0011] Furthermore, the preparation method of the nano-calcium carbonate modified with silane coupling agent KH560 is as follows: Nano-calcium carbonate and silane coupling agent KH560 were mixed uniformly in an ethanol / water mixed solvent with an ethanol volume fraction of 80% at a mass ratio of (1~3):(1-3). The mixture was reacted at room temperature for 5-10 hours, and then centrifuged, washed and dried to obtain the final product.

[0012] Furthermore, the mass ratio of the nano-calcium carbonate modified with silane coupling agent KH560 to the PDMS curing system is 1:1; the ratio of PDMS curing system to n-hexane solution is 1:40 (g:mL).

[0013] Further, the dopamine pretreatment step is as follows: immerse the polyurethane sponge in a Tris buffer solution with a concentration of 5-20 mmol / L and a pH of 8-9, and allow it to stand for 10-18 hours to carry out a self-polymerization reaction to form a polydopamine adhesion layer.

[0014] Furthermore, the PDMS curing system is composed of a mixture of PDMS prepolymer and curing agent, and the mass ratio of PDMS prepolymer to curing agent is (10-20):1.

[0015] Furthermore, the PDMS prepolymer is Sylgard 184A, and the curing agent is Sylgard 184B.

[0016] Furthermore, the conditions for high-temperature curing are: curing at 80-150℃ for 2-8 hours.

[0017] The environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge was prepared by the method described above.

[0018] The application of the environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge described above in oil-water separation.

[0019] The advantages and positive effects of this invention are as follows: 1. The preparation method of this invention is simple and efficient. The modified sponge material obtained, while completely eliminating fluorine compounds, still exhibits excellent hydrophobic properties, with a water contact angle as high as 136°. Furthermore, it demonstrates good cycle stability and environmental friendliness when treating oily produced water and organic solvent wastewater, avoiding the toxicity and environmental pollution problems of traditional fluorine-containing modifiers. This material can be recycled multiple times, has a high adsorption capacity retention rate, significantly improves oil-water separation efficiency and material lifespan, and has broad application prospects and promotional value.

[0020] 2. This invention utilizes the silane coupling agent KH560 to achieve effective silanization modification of nano-CaCO3, combined with a polydopamine adhesion layer formed by dopamine self-polymerization, to uniformly load nano-CaCO3 onto the surface of a polyurethane sponge skeleton, and constructs a low surface energy hydrophobic layer through cross-linking and curing of polydimethylsiloxane (PDMS), thus synergistically forming a composite material structure with "micro-nano rough structure-chemical bonding-hydrophobic modification", overcoming the shortcomings of existing oil-water separation materials such as poor environmental friendliness, high cost and limited adsorption capacity.

[0021] 3. The preparation method and materials provided by this invention offer a new solution for the development of green and efficient oil-water separation technology, and promote the environmental protection treatment of produced water and similar recalcitrant oil-water wastewater in the petroleum industry.

[0022] 4. The material of this invention is prepared by a green and environmentally friendly process, which solves the toxicity and environmental problems of fluorinated modifiers in traditional oil-absorbing materials. It has excellent hydrophobic and oleophobic properties and good stability for recycling, and is suitable for the efficient treatment of industrial produced water and oily wastewater.

[0023] 5. The material of this invention is an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge material. This material uses non-toxic, biocompatible nano-calcium carbonate (CaCO3) as the micro-nano rough structure building block, and fluorine-free, low surface energy polydimethylsiloxane (PDMS) as the hydrophobic coating. Through the bridging effect of dopamine, a stable composite functional layer is formed on the surface of the polyurethane sponge. This method avoids the environmental risks associated with the use of fluorine-containing compounds or toxic nanomaterials in traditional modification processes. The prepared sponge material exhibits both hydrophobic and oleophilic properties, high adsorption capacity for oils and organic solvents, good recycling performance, and can efficiently achieve oil-water separation. The overall process and materials used in this invention are green and safe, providing a high-performance and environmentally friendly solution for the treatment of oily wastewater.

[0024] 6. This invention is environmentally friendly and avoids harmful substances: This invention uses nano-CaCO3 and PDMS to modify polyurethane foam, completely eliminating the need for traditional fluorinated compounds, avoiding environmental pollution problems caused by toxic and harmful substances, and achieving green, environmentally friendly, and safe application of the material.

[0025] 7. The present invention features synergistic structural enhancement, improving oil-water separation efficiency: By effectively silanizing nano-CaCO3 with a silane coupling agent, and combining it with an adhesion layer formed by dopamine self-polymerization and a hydrophobic coating of PDMS, the material exhibits a micro-nano-scale rough structure and stable chemical bonding, which significantly improves the surface hydrophobic and oleophobic properties, and significantly enhances the oil-water separation efficiency and adsorption capacity.

[0026] 8. The excellent adsorption performance and cycle stability of this invention: The modified material exhibits a high adsorption capacity of 20–25 g / g for organic solvents such as dichloromethane, trichloromethane, diesel oil, soybean oil, and n-hexane. Especially for dichloromethane and trichloromethane, the adsorption capacity retention rate is about 85–92% after 9 adsorption-desorption cycles, demonstrating excellent mechanical strength and durability, and is suitable for repeated use.

[0027] 9. The process of this invention is simple and easy to scale up for production: The preparation process is mild, using conventional processes such as solution impregnation and thermosetting, avoiding complex equipment and high energy consumption, reducing production costs, and facilitating industrial promotion and large-scale production.

[0028] 10. The present invention exhibits excellent mechanical flexibility and chemical stability: The material matrix is ​​polyurethane foam, combined with nano-silanized particles and PDMS coating, which has good elasticity and durability, can adapt to complex water quality environments, extend service life and reduce maintenance frequency.

[0029] 11. This invention has broad application prospects and promotes resource recycling: The material is suitable for the efficient treatment of produced water from oil fields and various oily wastewaters. It not only purifies water bodies and improves environmental quality, but also enables the recovery of oil resources, meeting the requirements of green environmental protection and sustainable development. Attached Figure Description

[0030] Figure 1 This is a picture of the finished product of the modified polyurethane sponge obtained in Example 1 of the present invention; Figure 2 The images shown are (c) SEM images and (d) EDS images of the original sponge (a), the single-loaded modified calcium carbonate sponge (b), and the sponge loaded with nano-CaCO3 and PDMS in Example 1 of the present invention. Figure 3 The graph shows the selective absorption of n-hexane and trichloromethane by the modified polyurethane sponge prepared in Example 1 of the present invention on water (a, b, c, from a to c is a gradual adsorption process) and underwater (d, e, f, from d to f is a gradual adsorption process). Figure 4 This is a diagram showing the saturated adsorption capacity of the modified polyurethane sponge prepared in Example 1 of the present invention for various oils and organic solvents. Figure 5 This is a graph showing the data of nine cycles of adsorption of various oils and organic solvents by the modified polyurethane sponge prepared in Example 1 of the present invention. Figure 6 This is a comparative analysis of the acute and chronic toxicity of (a, b) CaCO3 and (c, d) PDMS dissolved in water by the modified polyurethane sponge prepared in Example 1 of the present invention to fish, water fleas and green algae. Figure 7 This is a schematic diagram showing the effect of different soaking times on the adsorption capacity of three solvents on the modified polyurethane sponge prepared in Example 1 of the present invention under hydrochloric acid conditions at pH=1, and the soaking state. Figure 8 This is a schematic diagram showing the effect of different soaking times on the adsorption capacity of three solvents and the soaking state of the modified polyurethane sponge prepared in Example 1 of the present invention under the condition of sodium hydroxide at pH=12. Figure 9 This is a schematic diagram of a process flow for the method of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the embodiments. The following embodiments are descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0032] The various experimental operations involved in the specific embodiments are all conventional techniques in the field. For parts not specifically annotated in this document, those skilled in the art can refer to various commonly used reference books, scientific and technological documents or related instructions and manuals prior to the filing date of this invention to carry out the operations.

[0033] A method for preparing an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge, such as... Figure 9 As shown, the method involves ultrasonically dispersing nano-calcium carbonate modified with silane coupling agent KH560 and PDMS curing system in a hexane solution, then immersing a dopamine-pretreated polyurethane sponge in the solution for 15-30 minutes to achieve uniform loading of nano-CaCO3, followed by high-temperature curing to obtain an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge.

[0034] Preferably, the method for preparing the nano-calcium carbonate modified with silane coupling agent KH560 is as follows: Nano-calcium carbonate and silane coupling agent KH560 were mixed uniformly in an ethanol / water mixed solvent with an ethanol volume fraction of 80% at a mass ratio of (1-3):(1-3). The mixture was reacted at room temperature for 5-10 hours, and then centrifuged, washed and dried to obtain the final product.

[0035] Preferably, the mass ratio of the nano-calcium carbonate modified with silane coupling agent KH560 to the PDMS curing system is 1:1; the ratio of PDMS curing system to n-hexane solution is 1:40 (g:mL).

[0036] Preferably, the dopamine pretreatment step is as follows: immersing a polyurethane sponge in a dopamine-Tris buffer solution with a concentration of 5-20 mmol / L and a pH of 8-9, and allowing it to stand for 10-18 hours to carry out a self-polymerization reaction to form a polydopamine adhesion layer.

[0037] Preferably, the PDMS curing system is composed of a mixture of PDMS prepolymer and curing agent, wherein the mass ratio of PDMS prepolymer to curing agent is (10-20):1.

[0038] Preferably, the PDMS prepolymer is Sylgard 184A and the curing agent is Sylgard 184B.

[0039] Preferably, the high-temperature curing conditions are: curing at 80-150℃ for 2-8 hours.

[0040] The environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge was prepared by the method described above.

[0041] The application of the environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge described above in oil-water separation.

[0042] Specifically, the relevant preparation and testing methods are as follows: 1. Oil / organic solvent absorption capacity test To test the adsorption capacity of the modified polyurethane sponge, various organic compounds, including organic solvents and oils (n-hexane, diesel oil, chloroform, dichloromethane, and soybean oil), were selected. The initial weight of the sponge was recorded first. Then, the sponge was soaked in 50 mL of organic matter for 1 minute, and then the mass of the sponge was weighed. Adsorption capacity (g / g) is calculated according to formula (1): Text format: (1).

[0043] 2. Reusability test To evaluate the recyclability and durability of the modified polyurethane foam, the original weight was recorded. Then, it was repeatedly immersed in (dichloromethane, trichloromethane, n-hexane, soybean oil, and diesel oil) respectively, and after adsorption for 1 minute, it was weighed and recorded. Then, the desorption was repeated 9 times by squeezing to estimate the cyclic absorption performance of the modified polyurethane sponge, and the adsorption capacity was calculated according to formula (1).

[0044] 3. Stability test Modified polyurethane sponges were immersed in hydrochloric acid and sodium hydroxide solutions with pH values ​​of 1 and 12, respectively, for 1–5 hours. Afterward, they were removed and dried in a forced-air drying oven at 95 degrees Celsius for 1 hour, and the change in adsorption capacity was measured. An abrasion test was conducted on the modified polyurethane sponges using 800-grit sandpaper. During the experiment, the sample was placed surface-down on the sandpaper, and a load pressure of 100 g was applied, causing it to move back and forth 10 cm. The change in adsorption capacity was measured after each abrasion.

[0045] Example 1 A nano-CaCO3 / PDMS modified polyurethane foam material, the preparation method of which includes the following steps: Nano-CaCO3 and silane coupling agent KH560 were uniformly mixed at a mass ratio of 2:1 and reacted at room temperature for 6.5 hours in an ethanol / water mixed solvent with a volume fraction of 80% to obtain silanized nano-CaCO3.

[0046] The pre-cleaned polyurethane sponge was immersed in a dopamine solution with a pH of 8.5 and allowed to stand for 12 hours to carry out a self-polymerization reaction, forming a polydopamine adhesion layer on its surface; the polydopamine-coated sponge was then immersed in the dispersion of silanized nano-CaCO3 to achieve uniform loading of nano-CaCO3. The polyurethane sponge loaded with nano-CaCO3 was impregnated in a mixture of PDMS prepolymer and curing agent with a mass ratio of 10:1. The impregnation time was 15 minutes, followed by curing at 120°C for 2 hours to form a hydrophobic PDMS layer, thus obtaining the nano-CaCO3 / PDMS modified polyurethane sponge material.

[0047] The pre-cleaning process involves ultrasonically cleaning the polyurethane sponge sequentially with deionized water and anhydrous ethanol.

[0048] The dopamine solution was prepared from tris(hydroxymethyl)aminomethane hydrochloride buffer.

[0049] Hexane is used as a solvent when the PDMS prepolymer is mixed with the curing agent.

[0050] The modified sponge prepared had saturated adsorption capacities of 20.23 g / g and 23.5 g / g for dichloromethane and trichloromethane, respectively. After nine cycles of adsorption, it could still maintain 85-92% of the adsorption capacity, showing good performance.

[0051] Figure 1 This is a visual representation of the modified sponge prepared in this embodiment.

[0052] Figure 2 The surface morphology and EDS element distribution of the original sponge, CaCO3 sponge, and CaCO3 / PDMS modified sponge (i.e., the sponge material prepared in Example 1) are shown, as well as the unmodified polyurethane sponge. Figure 2 a) It possesses a uniform and interconnected three-dimensional open pore structure with a smooth surface and only a small amount of impurities from the transport process. Modified nano-calcium carbonate, after loading ( Figure 2 b) A large number of particulate nano-CaCO3 particles are uniformly attached to the pore walls without obvious agglomeration, and the pore wall roughness is increased. Further loading with a PDMS coating ( Figure 2 c) After that, the pore walls were covered with a continuous and uniform PDMS layer, and the nano-CaCO3 was partially encapsulated but still visible. EDS elemental analysis ( Figure 2 d) The uniformly distributed Si on the surface confirms PDMS coverage, the consistent distribution of Ca and C confirms nano-CaCO3 loading, the N element originates from dopamine or PDMS, and the O element reflects the oxidation characteristics of the sponge and coating. The results indicate that nano-CaCO3 and PDMS coatings were successfully loaded while maintaining the basic structure of the sponge.

[0053] Figure 3This invention describes the adsorption and collection process of n-hexane (a, b, c) above water and chloroform (d, e, f) underwater using CaCO3 / PDMS modified sponge (i.e., the sponge material prepared in Example 1). Hexane and chloroform were used as pollutants, representing light oil and heavy oil respectively, to verify the selective oil absorption performance of the CaCO3 / PDMS modified sponge. Experimental results show that when the CaCO3 / PDMS modified sponge comes into contact with hexane on the surface of water dyed with Sudan III, the hexane is rapidly adsorbed; when placed underwater and near chloroform also dyed with Sudan III, the chloroform is also rapidly absorbed within seconds. This demonstrates that the CaCO3 / PDMS modified sponge can effectively and selectively adsorb oil from oily wastewater.

[0054] Figure 4 This study demonstrates the adsorption capacity of CaCO3 / PDMS modified sponge (i.e., the sponge material prepared in Example 1) for different oils and organic liquids. An excellent adsorbent should be applicable to a wide range of adsorption targets. Therefore, this invention selected several typical organic liquids, including n-hexane, diesel oil, chloroform, dichloromethane, and soybean oil, and systematically studied the adsorption performance of the CaCO3 / PDMS modified sponge. Experimental results show that the composite material exhibits significant differences in adsorption for different types of organic liquids. Specifically, it exhibits a high adsorption capacity for chloroform, reaching 23.5 g / g, significantly better than n-hexane's 9.5 g / g. Furthermore, for high-viscosity oils such as diesel oil and soybean oil, the adsorption capacity is relatively low, mainly because the high viscosity hinders the diffusion of the liquid in the sponge pores, limiting the depth of the adsorption process. This indicates that the composite material also possesses certain adaptability in the adsorption of polar organic solvents.

[0055] Figure 5To demonstrate the cyclic adsorption capacity of the CaCO3 / PDMS modified sponge (i.e., the sponge material prepared in Example 1), multiple adsorption-desorption cycle tests were conducted on various oils (including chloroform, dichloromethane, n-hexane, diesel oil, and soybean oil) to evaluate its recyclability. During the experiments, the sponge underwent oil adsorption and mechanical extrusion desorption sequentially, completing a total of 9 cycles. The results showed that the composite material exhibited good adsorption capacity retention for different oils. For chloroform and dichloromethane, the initial adsorption capacities were as high as 23.5 g / g and 20.3 g / g, respectively; after 9 cycles, the adsorption capacities remained at approximately 18.3 g / g and 17.7 g / g, with retention rates of 78% and 87%, respectively. For hexane, diesel oil, and soybean oil, the initial adsorption capacities were 9.5 g / g, 12.1 g / g, and 22.2 g / g, respectively. After 9 cycles, they still maintained approximately 80%, 82%, and 75% of their initial capacities. This series of performance data indicates that the composite sponge retains good structural stability, durable hydrophobic function, and excellent cycle durability after multiple uses, demonstrating broad potential for practical applications.

[0056] To systematically assess the environmental toxicity risks of nano-calcium carbonate and polydimethylsiloxane (PDMS) in composite materials, this invention not only referenced the solubility and water release behavior of both reported in relevant literature, but also used ECOSAR software to simulate and compare their aquatic ecotoxicity parameters. For example... Figure 6 As shown, the water solubility of CaCO3 is 5.7 mg / L, while the water solubility of PDMS is as low as 5 × 10⁻⁶ mg / L. -6 Both CaCO3 and CaCO3 exhibit extremely low aqueous phase release rates (mg / L), demonstrating good environmental stability. In acute and chronic toxicity tests, the LC50 and EC50 values ​​of CaCO3 for fish, water fleas, and green algae were significantly higher than their dissolution concentrations. For example, the acute LC50 for CaCO3 in fish was as high as 4.13 × 10⁻⁶ mg / L. 5 mg / L, the LC50 and EC50 for Daphnia and Green Algae were 1.6 × 10 mg / L and 1.6 × 10 mg / L, respectively. 5 mg / L and 2.48×10 4 mg / L, significantly higher than its solubility in water (see mg / L). Figure 6 a and Figure 6 b). Similarly, PDMS has lower solubility in water and lower levels of acute and chronic toxicity (LC50 and EC50) to all three types of aquatic organisms. Figure 6 c and Figure 6 d), the concentration of its toxic effect is much higher than the actual release amount.

[0057] Figure 7 and Figure 8The diagram illustrates the effect of different soaking times on the adsorption capacity of three solvents under pH=1 and pH=12 conditions, along with the soaking state. Considering that the CaCO3 / PDMS modified sponge (i.e., the sponge material prepared in Example 1) may encounter extreme acid and alkali environments in practical applications, this invention systematically studied its chemical stability under strong acid (pH=1) and strong alkali (pH=12) conditions. The data in the figure show that after soaking in acidic media for a certain time, the adsorption capacity for dichloromethane, trichloromethane, and n-hexane only slightly decreased, indicating its good acid resistance. In alkaline environments, the material's adsorption performance remained stable, with no significant degradation observed, further verifying its excellent alkali resistance. No significant corrosion or morphological damage was observed on the material surface during soaking, indicating that its microstructure has excellent resistance to both strong acids and alkalis. This performance is attributed to the chemical inertness of the PDMS layer and the stable structure of the CaCO3 framework, ensuring the long-term stability of the material in complex chemical environments.

[0058] Example 2 A nano-CaCO3 / PDMS modified polyurethane sponge material is prepared using a method basically the same as that in Example 1, except that: Nano-CaCO3 and silane coupling agent KH560 were uniformly mixed at a mass ratio of 2:3 and reacted at room temperature for 6.5 hours in an ethanol / water mixed solvent with a volume fraction of 80% to obtain silanized nano-CaCO3.

[0059] The pre-cleaning treatment, polydopamine modification, nano-CaCO3 loading, and PDMS hydrophobic layer curing steps are all the same as in Example 1.

[0060] The modified sponge prepared had saturated adsorption capacities of 20.41 g / g and 23.6 g / g for dichloromethane and trichloromethane, respectively. After nine cycles of adsorption, it could still maintain 86-90% of the adsorption capacity, showing good performance.

[0061] Comparative Example 1 Its preparation method is exactly the same as that in Example 1, except that: Replace PDMS with OTS.

[0062] The modified sponge prepared had saturated adsorption capacities of 10.3 g / g and 12.4 g / g for dichloromethane and trichloromethane, respectively, and could only maintain 35-47% of its adsorption capacity after 9 cycles of adsorption.

[0063] Comparative Example 2 Its preparation method is exactly the same as that in Example 1, except that: Replace nano-calcium carbonate with silicon dioxide.

[0064] The modified sponge had saturated adsorption capacities of 9.4 g / g for dichloromethane and 11.3 g / g for trichloromethane, and after 9 cycles of adsorption, it could only maintain 33% to 39% of the adsorption capacity.

[0065] It can also be seen that PDMS and nano-calcium carbonate have a synergistic effect in the method of the present invention, which can synergistically improve the relevant properties of the prepared nano-CaCO3 / PDMS modified polyurethane sponge material, especially the saturated adsorption capacity and the adsorption capacity after cyclic adsorption of the prepared nano-CaCO3 / PDMS modified polyurethane sponge material.

[0066] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing an environmentally friendly nano-CaCO3 / PDMS modified polyurethane sponge, characterized in that: The method is to ultrasonically disperse silane coupling agent KH560 modified nano calcium carbonate and PDMS curing system in n-hexane solution, then immerse dopamine pretreated polyurethane sponge therein for 15-30 minutes to realize uniform loading of nano CaCO3, and high temperature curing to obtain environment-friendly nano CaCO3 / PDMS modified polyurethane sponge.

2. The method of claim 1, wherein: The preparation method of the silane coupling agent KH560 modified nano calcium carbonate is as follows: The nano calcium carbonate and the silane coupling agent KH560 are uniformly mixed in an ethanol / water mixed solvent with an ethanol volume fraction of 80% according to a mass ratio of (1-3):(1-3), and are reacted at room temperature for 5-10 hours, and then are centrifuged, washed and dried to obtain.

3. The method of claim 1, wherein: The mass ratio of the silane coupling agent KH560 modified nano calcium carbonate and the PDMS curing system is 1:1; the ratio of the PDMS curing system to n-hexane solution is 1:

40.

4. The method of claim 1, wherein: The dopamine pretreatment step is as follows: the polyurethane sponge is soaked in dopamine-Tris buffer solution with a concentration of 5-20 mmol / L and a pH of 8-9, and is left to stand for self-polymerization reaction for 10-18 hours to form a polydopamine adhesion layer.

5. The method of claim 1, wherein: The PDMS curing system is composed of PDMS prepolymer and a curing agent, and the mass ratio of the PDMS prepolymer to the curing agent is (10-20):

1.

6. The method of claim 1, wherein: The PDMS prepolymer is Sylgard 184A, and the curing agent is Sylgard 184B.

7. The method of making according to any one of claims 1 to 6, wherein: The high temperature curing condition is as follows: curing at 80-150℃ for 2-8 hours.

8. The environment-friendly nano CaCO3 / PDMS modified polyurethane sponge prepared by the preparation method in any one of claims 1 to 7.

9. The application of the environment-friendly nano CaCO3 / PDMS modified polyurethane sponge in oil-water separation.

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