CN115181326B - Solar-assisted modified sponge mediated by liquid-like nanofluid and preparation method thereof - Google Patents

Abstract

The invention relates to a liquid-like nano-fluid-mediated solar auxiliary modified sponge and a preparation method thereof, wherein the method comprises the following steps: 1. immersing the polyurethane sponge into a dopamine solution, and drying to obtain polyurethane/polydopamine modified sponge; 2. soaking polyurethane/polydopamine modified sponge into SiO ₂ Nanofluidic hexanol dispersion; obtain the liquid-like nano-fluid-mediated solar auxiliary modified sponge, wherein SiO (SiO) in the modified sponge ₂ The mass fraction of the nano fluid is 1-10%. The liquid-like nano fluid-mediated solar auxiliary modified sponge can be used for cleaning and recycling viscous crude oil leakage, has obvious viscosity reduction effect on the viscous crude oil through the synergistic effect of silica nano fluid lubrication and viscosity reduction and photo-thermal conversion of polydopamine, can accelerate the adsorption speed, and has the potential of quick recycling and efficient cleaning in the actual crude oil spilled oil cleaning application.

Description

Solar-assisted modified sponge mediated by liquid-like nanofluid and preparation method thereof

technical field

The invention relates to the field of modified sponges, in particular to a solar-assisted modified sponge mediated by liquid-like nanofluids and a preparation method thereof.

Background technique

Due to the rapid development of the petrochemical industry, serious offshore oil spills often occur around the world, which not only cause a serious waste of resources, but also cause immeasurable damage to the ecological environment and human health. Porous adsorbent material is considered to be the most promising new type of material for oil spill pollution, which has good mechanical properties, propagation properties, photoelectric properties, permeability, adsorption and chemical properties, researchers have developed many high-performance adsorption agent materials such as activated carbon, aerogels, sponges, and membranes. Among them, polyurethane sponge is more commonly used because of its internal "honeycomb" shape, rich pores and connections, high porosity, low density, high elasticity, and strong absorption capacity. However, polyurethane sponge adsorbents usually focus on low-viscosity oils (viscosity <100mPa.s), but are ineffective or even ineffective for high-viscosity crude oil (viscosity>1000mPa.s). According to current literature reports, the heat absorbed by light or magnetism can increase the temperature of crude oil, thereby reducing the viscosity of crude oil and increasing the diffusion coefficient of crude oil in the sponge pores, thereby accelerating the absorption rate. Therefore, it is particularly necessary to develop a sponge (PSiNFs@PU) that can absorb crude oil ultrafast and has high absorption capacity and recovery rate. Inspired by light and heat to reduce the viscosity of crude oil, breaking through the conventional preparation method, when the sponge is placed in the sun, the viscosity of the viscous oil around the sponge will be greatly reduced. On the one hand, because the silica nanofluid has a double-layer ion structure, it can not only wrap the oil in combination with surfactants, thereby producing the function of low resistance, but also allow crude oil to penetrate into every corner of the skeleton, increasing the capacity ; On the other hand, silica nanofluid itself has a remarkable feature, it can not only absorb oil but also has a very low viscosity, so the frictional resistance produced will be reduced, and these factors will make the capillary siphon effect of the sponge more obvious.

Based on this unique idea, with the goal of a liquid-like nanofluid-mediated solar energy-assisted sponge modification, the impregnation method was used to make use of the excellent adhesion properties of polydopamine, and the silica nanofluid adhered to the polyurethane sponge. And because the polydopamine coating has a molecular structure similar to that of melanin, the oxidation of dopamine makes polydopamine have a significant absorption capacity for visible light, and the self-polymerization reaction will promote the absorption spectrum of polydopamine to extend to the near-infrared region, which has excellent Light-to-heat conversion performance. The solar-assisted modified sponge, which is used for efficient cleaning and recycling of viscous crude oil spills, can reduce the viscosity of crude oil and absorb crude oil super fast, which solves the key problem of the ability to absorb more oil in a short period of time when an oil spill occurs . Compared with the traditional method, the new method has the following advantages: 1) The process is simple, the reaction cycle is short, non-toxic and environmentally friendly; 2) The solar energy-assisted modified sponge reduces the viscosity of crude oil; 3) It can achieve viscosity reduction, and the absorption capacity and recovery rate are relatively high high. Therefore, it is of great significance to develop an environmentally friendly viscosity-reducing crude oil preparation process through the impregnation method, with the solar-assisted modified sponge for the cleaning and recovery of viscous crude oil spills, efficient removal of high-viscosity crude oil and ultra-fast and efficient recovery of adsorbent materials. .

Contents of the invention

For the problems referred to above, the object of the present invention is to provide a kind of liquid nanofluid-mediated solar energy-assisted modified sponge and preparation method thereof, which are used for cleaning and reclaiming preparation methods of viscous crude oil spills.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

A preparation method for solar-assisted modified sponge mediated by liquid nanofluids, comprising the following steps:

Step 1, immersing the polyurethane sponge in the dopamine solution to obtain a polyurethane/polydopamine modified sponge;

Step 2, immerse the polyurethane/polydopamine modified sponge prepared in the previous step into the _SiO nanofluid to obtain the solar-assisted modified sponge mediated by liquid-like nanofluid, and the solar-assisted modified sponge mediated by liquid-like nanofluid The mass fraction of _SiO2 nano-like fluid in the sex sponge is 1-10%.

Further, said step 1 includes the following steps:

Step 1.1, cut the polyurethane sponge into flakes, alternately clean it with distilled water and absolute ethanol for 30 minutes, put it in an oven to dry after cleaning, and obtain the cleaned polyurethane sponge;

Step 1.2. Put dopamine hydrochloride and TRIS reagent into deionized water, add TRIS reagent to make the aqueous solution alkaline, put the polyurethane sponge cleaned in step 1 into a beaker, shake for more than 48 hours, and finally place it in a vacuum oven at 50-60°C Dry to obtain polyurethane/polydopamine modified sponge.

Further, the step 2 specifically includes the following steps:

Step 2.1, take an appropriate amount of SiO ₂ nano-fluid and ultrasonically disperse it in 100mL of absolute ethanol, immerse the prepared PDAPU in the SiO ₂ nano-fluid, squeeze repeatedly, and then place it for more than 12 hours to make the silica nano-fluid adhere completely On polyurethane/polydopamine modified sponge;

Step 2.2, take out the sponge soaked in the previous step, and dry it in an oven to obtain a polyurethane/polydopamine/silica nano-fluid modified sponge, and calculate the density of the silica nano-fluid in the polyurethane/polydopamine modified sponge. The mass fraction is to control the mass fraction of the _SiO2 nano-fluid in the modified sponge to be 1-10% by repeating the dipping process several times.

A kind of liquid nanofluid mediated solar-assisted modified sponge is prepared by the above-mentioned method.

The beneficial effects of the present invention are: since the sponge adsorbent is usually concentrated in low-viscosity oil (viscosity<100mPa.s), it is ineffective or even invalid for crude oil (viscosity>1000mPa.s). The present invention discovers through experiments that low-content silica nanofluids have lubricating and viscosity-reducing effects on crude oil. On the one hand, because silica nanofluids have a double-layer ion structure, they can wrap oil in combination with surfactants. , so that the resistance is very small, and the crude oil can penetrate into every corner of the skeleton to increase the capacity; Very low, resulting in reduced frictional resistance, these factors will make the capillary siphon effect of the sponge more obvious. In addition, polydopamine has excellent light-to-heat conversion performance, because the polydopamine coating has a molecular structure similar to that of melanin, and the oxidation of dopamine makes polydopamine have a significant absorption capacity for visible light, and the self-polymerization reaction that occurs will promote polydopamine. The absorption spectrum extends to the near-infrared region, which has excellent photothermal conversion performance. Through the lubricating and viscosity-reducing effects of nano-silica fluids and the synergistic effect of photothermal conversion of polydopamine, the modified sponge can absorb crude oil ultra-fast. Therefore, the present invention prepares one. The sponge has obvious viscosity-reducing effect on viscous crude oil, and can also speed up the adsorption speed, and the oil absorption efficiency can reach 99%.

Description of drawings

Figure 1 is a flow chart of the preparation of PSiNFs@PU;

Figure 2 shows the percentage of the absorbed oil of PUS, PDAPU and PSiNFs@PU in their saturated oil absorption when PSiNFs@PU absorbs different types of oil and reaches saturation;

Figure 3 is the thermal imaging photos of PUS, PDAPU, PU@SiNFs and PSiNFs@PU sponge under one sun illumination (power density: 1.00kW/m ² );

Figure 4 shows the penetration behavior of crude oil droplets on the surface of PUS and PSiNFs@PU with and without light;

Figure 5 shows the viscosity change of crude oil with different _SiO2 nanofluid contents at 60 °C.

Figure 6 shows the carbon content and limiting oxygen index of PUS, PDA@PU and PSiNFs@PU.

Detailed ways

Principle of the present invention and feature are described below in conjunction with specific embodiment, and given example is only used to explain the present invention, is not intended to limit the scope of the present invention.

Example 1

Cut the polyurethane sponge into 1cm×2cm×2cm slices, ultrasonically clean them with distilled water and absolute ethanol for 30 minutes, clean them, and dry them in an oven. Then put 1g of dopamine hydrochloride and 0.98g of TRIS reagent into 500mL deionized water, add TRIS reagent to make the aqueous solution alkaline, put the cleaned polyurethane sponge into a beaker, shake for 48h, and obtain the polyurethane sponge adhered to dopamine. Dry in a vacuum oven at 50°C to obtain a polyurethane/polydopamine modified sponge (PDAPU). Take an appropriate amount of _SiO2 nanofluid and ultrasonically disperse it in 100mL of absolute ethanol for 30min, immerse the prepared PDAPU in the _SiO2 nanofluid, squeeze repeatedly for 10min, and then place it for 12h to make the silica nanofluid completely adhere to the On the PDAPU, the soaked sponge was taken out and dried in an oven to obtain a polyurethane/polydopamine/silica nano-fluid modified sponge (PSiNFs@PU). Finally calculate the percentage of fluid based on the mass of PDAPU. By repeating the impregnation process several times, the content of _SiO2 nanofluid in the modified sponge can be adjusted, taking the mass fraction as 10 wt%, respectively.

Example 2

Cut the polyurethane sponge into 1cm×2cm×2cm slices, ultrasonically clean them with distilled water and absolute ethanol for 30 minutes, clean them, and dry them in an oven. Then put 1g dopamine hydrochloride and 0.98g TRIS reagent into 500ml deionized water, add TRIS reagent to make the aqueous solution alkaline, put the polyurethane sponge after cleaning into a beaker, shake for 48h, and obtain the polyurethane sponge adhered to dopamine, and finally put it in Dry in a vacuum oven at 50°C to obtain a polyurethane/polydopamine modified sponge (PDAPU). Take an appropriate amount of _SiO2 nano-fluid and ultrasonically disperse it in 100mL absolute ethanol for 30min, immerse the prepared PDAPU in the _SiO2 nano-fluid, repeatedly extrude for 10min, then place it for 12h, so that the silicon dioxide nanofluid is completely adhered to the On the PDAPU, the soaked sponge was taken out and dried in an oven to obtain a polyurethane/polydopamine/silica nano-fluid modified sponge (PSiNFs@PU). Finally calculate the percentage of fluid based on the mass of PDAPU. By repeating the impregnation process several times, the content of _SiO2 nano-fluids in the modified sponge can be adjusted, taking the mass fraction as 20wt% respectively.

Example 3

Cut the polyurethane sponge into 1cm×2cm×2cm slices, ultrasonically clean them with distilled water and absolute ethanol for 30 minutes, clean them, and dry them in an oven. Then put 1g of dopamine hydrochloride and 0.98g of TRIS reagent into 500mL deionized water, add TRIS reagent to make the aqueous solution alkaline, put the cleaned polyurethane sponge into a beaker, shake for 48h, and obtain the polyurethane sponge adhered to dopamine. Dry in a vacuum oven at 50°C to obtain a polyurethane/polydopamine modified sponge (PDAPU). Take an appropriate amount of SiO ₂ nanofluid and ultrasonically disperse it in 100mL of absolute ethanol for 30min, immerse the prepared PDAPU in the SiO ₂ nanofluid, squeeze it repeatedly for 10min, and then place it for 12h, so that the silica nanofluid can completely adhere to the PDAPU Then, the soaked sponge was taken out and dried in an oven to obtain a polyurethane/polydopamine/silica nano-fluid modified sponge (PSiNFs@PU). Finally calculate the percentage of fluid based on the mass of PDAPU. By repeating the impregnation process several times, the content of _SiO2 nano-fluids in the modified sponge can be adjusted, taking the mass fraction as 30wt% respectively.

Example 4

Cut the polyurethane sponge into 1cm x 2cm x 2cm slices, wash them with distilled water and absolute ethanol ultrasonically for 30 minutes, clean them, and dry them in an oven. Get an appropriate amount of SiO ₂ nano-fluids in 100mL absolute ethanol and ultrasonically disperse them for 30 min, immerse the cleaned polyurethane sponge in the SiO ₂ nano-fluids, repeatedly extrude for 10 min, then place it for 12 hours, and finally find that SiO ₂ nano-fluids directly It is dissolved in the oil, and it does not have a good adhesion to the polyurethane sponge. Not only is it non-adhesive, but the surface temperature can only reach a maximum of about 50 degrees after photothermal, and there is no photothermal effect.

Show by four kinds of examples, different mass fraction silicon dioxide nano class fluids show to crude oil viscosity, SiO ₂ fluid content has viscosity reduction when 10wt%, and original SiO ₂ fluid content is not obvious when 20wt%, 30wt% Viscosity-reducing properties, indicating that low-content silica nano-fluids have a lubricating and viscosity-reducing effect on crude oil. Therefore, the photothermal synergistic effect of silica nanofluid and polydopamine makes PSiNFs@PU sponge significantly reduce the viscosity of viscous crude oil, greatly improving the oil absorption rate of PSiNFs@PU sponge to viscous crude oil, and the absorption capacity and The high recovery rate makes practical large-scale application possible.

As shown in FIG. 1 , it is a flow chart of the preparation of PSiNFs@PU of the present invention. Put the cleaned polyurethane sponge into a beaker and shake it for 48 hours at pH = 8.5 to obtain a dopamine-adhered polyurethane sponge. Through a simple and gentle dip coating, a uniform layer of dopamine is covered on the skeleton of the porous sponge Dopamine deposition layer. Subsequently, the PDAPU is immersed in the _SiO2 nanofluid so that the silica nanofluid is completely adhered to the PDAPU. Due to the good adhesion of polydopamine, the silica nanofluid particles are evenly fixed on the surface of the sponge skeleton. The resulting polyurethane/polydopamine/silica nanofluid modified sponge (PSiNFs@PU) finally obtained modified sponges with different mass fractions of fluid.

As shown in Figure 2, the time for the original sponge to absorb crude oil is more than 12 hours, while the time for the modified sponge to absorb crude oil is 5 minutes, and the oil absorption efficiency can be increased by 99%. When PSiNFs@PU reaches oil absorption saturation, polyurethane sponge (PUS) , PDAPU sponge, and polyurethane/silica nanofluid-modified sponge (PU@SiNFs) have much lower oil absorption than PSiNFs@PU, indicating that PSiNFs@PU can quickly and effectively clean a variety of oil stains.

As shown in Fig. 3, the surface equilibrium temperature of PUS sponge increased slightly from 29.7 °C to 38.6 °C, while that of PSiNFs@PU reached 87.3 °C, and its heating rate and final equilibrium temperature were much higher than that of PUS sponge.

As shown in Figure 4, the PUS sponge has poor adsorption of crude oil with or without light, and for the PSiNFs@PU sponge, crude oil completely penetrates into the same sponge within 1 s under one sunlight irradiation , while in the absence of light, this time increases to 4.2s. Because the viscosity of crude oil decreases sharply at high temperature, the kinetics of oil absorption is improved, making crude oil flow freely like light oil. The above phenomena show that PSiNFs@PU sponge can significantly reduce the viscosity of crude oil under the photothermal effect, and can effectively adsorb high-viscosity crude oil.

As shown in Figure 5, when the silicon dioxide nanofluid content is 0.5wt%, the viscosity of the sample is all less than the viscosity of crude oil, which confirms that the low content silicon dioxide nanofluid has the viscosity-reducing effect of lubricating effect on crude oil, so , the photothermal synergistic effect of silica nano-fluid and polydopamine makes PSiNFs@PU sponge have obvious viscosity-lowering effect on viscous crude oil, which greatly improves the oil absorption efficiency of PSiNFs@PU sponge to viscous crude oil, making the actual large-scale application becomes possible.

As shown in Fig. 6, in order to evaluate the flame retardancy of PUS and PSiNFs@PU sponges, the carbon content was obtained and the limiting oxygen index was calculated and compared. By coating PDA layer and SiO ₂ nfs layer on the sponge, the residual carbon rate increased from 0.33% to 7.56% and 8.01%, respectively. This means that the PDA layer can promote the formation of carbon in the matrix and reduce combustible substances.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the present invention. within the scope of protection.

Claims (4)

1. The preparation method of solar energy-assisted modified sponge mediated by liquid-like nanofluids is characterized in that, comprising the following steps: Step 1, immersing the polyurethane sponge in the dopamine solution to obtain the polyurethane/polydopamine modified sponge; Step 2, immerse the polyurethane/polydopamine modified sponge prepared in the previous step into the _SiO nanofluid to obtain the solar-assisted modified sponge mediated by liquid-like nanofluid, and the solar-assisted modified sponge mediated by liquid-like nanofluid The mass fraction of _SiO2nano- like fluid in the sponge is 1-10%; SiO was prepared by polycondensation of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride onto the surface of silica followed by ion exchange with sodium nonylphenol ethoxylate sulfate ₂ nanofluids. 2. the method for preparing the solar-assisted modified sponge mediated by liquid-like nanofluids according to claim 1, wherein said step 1 comprises the following steps: Step 1.1. Cut the polyurethane sponge into flakes, alternately clean it with distilled water and absolute ethanol ultrasonically for 30 minutes, put it in an oven to dry after cleaning, and obtain the cleaned polyurethane sponge; Step 1.2, put dopamine hydrochloride and TRIS reagent into deionized water, add TRIS reagent to make the aqueous solution alkaline, put the polyurethane sponge cleaned in step 1.1 into a beaker, shake for more than 48 h, and finally place in a vacuum oven at 50-60°C Dry in medium to obtain polyurethane/polydopamine modified sponge. 3. the method for preparing the solar-assisted modified sponge mediated by liquid-like nanofluids according to claim 1, wherein said step 2 specifically comprises the following steps: Step 2.1. Take an appropriate amount of SiO ₂ nano-fluid and ultrasonically disperse it in 100 mL of absolute ethanol. Immerse the prepared polyurethane/polydopamine modified sponge in the SiO ₂ nano-fluid, squeeze it repeatedly, and then place it for more than 12 h. Silica nanofluid is completely adhered to the polyurethane/polydopamine modified sponge; Step 2.2, take out the sponge soaked in step 2.1, put it in an oven to dry, obtain polyurethane/polydopamine/silica nano-fluid modified sponge, and calculate the density of silica nano-fluid in polyurethane/polydopamine modified sponge Mass fraction, by repeating the dipping process many times, the mass fraction of _SiO2 nano-fluid in the modified sponge is controlled at 1-10%. 4. The solar-assisted modified sponge mediated by liquid-like nanofluids, characterized in that it is prepared by the method described in any one of claims 1-3.

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