CN104338519A - Modified graphene-loaded polyurethane sponge and preparation method thereof - Google Patents

Abstract

The invention relates to modified graphene-loaded polyurethane sponge which is characterized in that a modified graphene coating is loaded on the surface of the polyurethane sponge, and is 0.5mm-1.0mm thick, a silane coupling agent is coated on the surface of the modified graphene, wherein the mass ratio of the silane coupling agent to the graphene is 1 to 100. Experiments prove that by measuring the dewatering effect and the oil absorption capability of the loaded sponge, the sponge is super-hydrophobic from hydrophilic (a contact angle is 161 degrees), the oil absorption capability is remarkably enhanced, and the saturation adsorption amount for diesel reaches 37.89g. According to the modified graphene-loaded polyurethane sponge, the modified graphene is loaded on the sponge by using the silane coupling agent, so that the sponge has super-hydrophobic and super-oleophylic performances, and has a potential application value in a process of remediating a petroleum pollution water body.

Description

Modified graphene-loaded polyurethane sponge and preparation method thereof

technical field

The invention relates to a modified graphene-loaded polyurethane sponge and a preparation method thereof.

Background technique

With the rapid development of modern industry, the increasing scarcity of land resources and the rapid growth of human demand for energy, shallow sea oil and gas resources have been continuously developed. However, with the development of submarine oil and crude oil, their products are also continuously transported at sea, which inevitably produces many marine oil pollution incidents, such as blowout accidents during development and leakage accidents from transport tankers. Oil spills on the ocean not only brought us huge economic losses, but more importantly, caused significant pollution to the marine ecological environment and surrounding coasts. First of all, oil will seriously endanger the survival of aquatic organisms. After marine mammals ingest oil spills, their visceral functions will be damaged. Certain oil components can make mammals and free fungi lose their sense of chemical stimulation and hinder The transfer of chemical information between aquatic organisms; oil pollution will make the feathers of waterfowls lose their waterproof and warm-keeping effect, and it will be difficult to fly with oily wings. Studies have shown that as long as there is an extremely thin oil film on the water surface, the "input" of sunlight and air to the water body will be significantly changed, thereby causing the death of seaweed and other low-level aquatic organisms eaten by birds. Coupled with the toxicity of the oil, the ecological environment has deteriorated sharply, and it can even induce marine red tides. According to reports, over the past 50 years, more than 1,000 species of marine life have become extinct due to oil pollution, and marine life has decreased by 40%. In addition, oil spills also have an important impact on human health. Comet analyzed the accumulation of toxins in shellfish polluted by oil spills through experiments, and found a certain concentration of polycyclic aromatic hydrocarbons (PAH). Such as carcinogens into the body. Furthermore, the diffusion of organic vapors formed by volatilization of oil into the atmosphere will also pollute the atmospheric environment and cause photochemical smog, which will also stimulate human vision, damage organic matter in the environment, and cause plant necrosis.

In order to control marine oil pollution and minimize its harm, many scholars at home and abroad have conducted various researches. At present, the common treatment methods include mechanical method, combustion method, bioremediation method, material absorption method and so on. The physical mechanical recovery method not only solves the problem of oil slicks on the ocean, but also recycles energy without wasting energy. However, the oil boom cannot ensure rapid and complete control of the oil diffusion trend, so it still has certain limitations. The combustion method seems to be the simplest method, but the products after combustion will cause secondary pollution to the environment, so all oil spills on the high seas have not adopted this method so far. Bioremediation is mostly implemented by surfactants, especially biosurfactants that combine the hydrophobicity of surfactants and the degradation function of microorganisms, which can achieve high efficiency, non-toxic, antibacterial, economical, easy to degrade and no secondary Pollution and other advantages, but considering the industrial cost, ecological balance and long time, it is not often used for oil spill pollution treatment. At present, the material absorption method has become the preferred method for oil spill pollution treatment due to its high efficiency, rapidity, no secondary pollution, and the ability to recycle. The types of absorbents today include polymeric absorbents, natural material absorbents, and fiber material absorbents. Among them, graphene has been used as a coating material due to its unique two-dimensional structure and special hydrophobic and lipophilic properties. It has become a hotspot in the research of oil-absorbing materials, but the method of using γ-methacryloxypropyltrimethoxysilane (KH-570) to modify graphene loaded on polyurethane sponge has not been studied.

Contents of the invention

One of the objects of the present invention is to provide a modified graphene loaded polyurethane sponge.

Two of object of the present invention is to provide the preparation method of this polyurethane sponge.

What the present invention provides is a method for making the surface of polyurethane sponge superhydrophobic and superoleophilic. The specific technical solution is: modify graphene oxide with the hydrolyzate of KH-570 and then reduce it to generate modified graphene , and load it on the surface of the sponge to form a material with superhydrophobic and superoleophilic properties, and test its hydrophobic and oil-absorbing properties.

To achieve the above object, the present invention adopts the following technical solutions:

A modified graphene-loaded polyurethane sponge is characterized in that the polyurethane sponge is loaded with a modified graphene coating on the surface of the polyurethane sponge, and the coating thickness is 0.5 ~ 1.0mm; the modified graphene is The surface of graphene is coated with silane coupling agent, wherein the mass ratio of silane coupling agent to graphene is 1:100.

The preparation method of the above-mentioned modified graphene-loaded polyurethane sponge is characterized in that the silane coupling agent has: γ-aminopropyltriethoxysilane (KH-550), γ-glycidyl etheroxypropyltrimethyl Oxysilane (KH-560), γ-methacryloxypropyltrimethoxysilane (KH-570), etc.

A method for preparing above-mentioned modified graphene loaded polyurethane sponge is characterized in that the concrete steps of the method are:

a. dissolving graphite oxide in absolute ethanol to prepare a suspension with a concentration of 2mg/ml;

b. Mix the silane coupling agent, distilled water and absolute ethanol in a volume ratio of 1:1:18, adjust the pH value of the solution to 4.0~4.5, and then add it to the suspension obtained in step a to make graphite oxide and The mass ratio of the silane coupling agent is 100:1; reflux reaction for 4 hours; then suction filtration, the filter cake is washed with distilled water, and then washed with ethanol, the obtained modified graphene oxide is scraped off the filter paper, fully dried and weighed ; Dispersed in ethanol solution, made into 2mg/ml graphene oxide ethanol suspension, reserved for use;

c. Immerse the cleaned polyurethane sponge in the suspension obtained in step b for 1 hour, then adjust the pH to 9, and then reduce the graphene oxide with hydrazine hydrate at 95°C for 1.5 hours; take out the sponge and wash it with deionized water , and dry to obtain the modified graphene-loaded polyurethane sponge

The adsorption rate of diesel oil on the sponge loaded with graphene modified by silane coupling agent is much higher than that of water, and its water absorption rate is significantly lower than that of the original sponge, while its oil absorption rate is increased, and the saturated adsorption capacity of diesel oil can reach 37.89g; the contact angle (CA) of the modified sponge to water is 161o, which is superhydrophobic. Therefore, loading graphene modified by silane coupling agent on the surface of polyurethane sponge makes the sponge, which is originally both water-absorbing and oil-absorbing, have good hydrophobicity and stronger oil absorption. The sponge material prepared by the modified graphene-loaded sponge has greater potential in the application of adsorbing petroleum pollutants in water bodies.

Description of drawings

Figure 1: Visual comparison of original sponge (a) and modified sponge (b).

Figure 2: Comparison of the hydrophobic contact angle (CA) of the original sponge (a) and the modified sponge (b).

Figure 3: Scanning electron microscope (SEM) comparison of original sponge (a) and modified sponge (b).

Detailed ways

1. Material preparation

(1) Preparation of reagents

The main reagents are: concentrated sulfuric acid (H ₂ SO ₄ , 98%), sodium nitrate (NaNO ₃ ), ammonia water (NH ₄ OH), glacial acetic acid (CH ₃ COOH), potassium permanganate (KMnO ₄ ), peroxide Hydrogen (H ₂ O ₂ , 30%), hydrochloric acid (HCl, 5%), barium chloride (BaCl ₂ ), absolute ethanol (CH ₃ CH ₂ OH), γ-methacryloxypropyl trimethyl Siloxane (KH-570), Hydrazine Hydrate (N ₂ H ₄ ·H ₂ O).

For the preparation method of graphite oxide, please refer to the literature: Singh, E., Chen, Z., Houshmand, F., Ren, W., Peles, Y., Cheng, H. M. and Koratkar, N., Superhydrophobic graphene foams, Small, 2013, 9(1): 75-80.

(2) Test sponge

Polyurethane sponge (density 0.025g/cm ³ ), purchased from a local manufacturer.

(3) Experimental instruments and equipment

Collector magnetic stirrer, FA1004B—analytical balance, vacuum drying oven, oven, ultrasonic cleaner, high-speed centrifuge, water bath, vacuum filter pump, magnetic stirring oil bath

2. Treatment of sponges and determination of their hydrophobic and lipophilic properties

(1) Disposal of sponge

The sponges were ultrasonically cleaned with deionized water and ethanol until use.

(2) Test oil

Zero Diesel (Sinopec Minghe Gas Station).

Embodiment one:

1) Preparation of graphene oxide (GO). The main method is to add 2g of natural flake graphite to a 500mL beaker in an ice-water bath, then add 46mL of concentrated H ₂ SO ₄ (98%), add 1g of NaNO ₃ , control the temperature below 20°C, and add 6g of KMnO while stirring. _4. Raise the temperature to 35~36°C, keep the solution at this temperature for 1.5 hours, at this time, gas will be released; slowly add 92mL deionized water into the mixture, then raise the temperature of the water bath to 98°C, and keep it there 15min to increase the oxidation degree of GO; dilute the mixed solution with 280mL deionized water, and slowly add 6mL 30% H ₂ O ₂ solution to the above solution, if no bright yellow is formed, continue to drop until bright yellow is formed , the mixture was suction filtered or centrifuged, washed with 5% HCl solution several times until no SO ₄ ^2- was detected with BaCl ₂ , then washed with deionized water several times to remove the acid, and the obtained filtered block was °C, dried and weighed for later use.

2) Preparation of KH-570 modified graphene oxide. Add 100mg GO into a 250ml beaker, add 100ml absolute ethanol to form a suspension, and sonicate for 2h. Take another clean small beaker, add 10ml of silane coupling agent KH-570, then add 10ml of distilled water and 180ml of absolute ethanol solution (the volume ratio of the three is 1:1:18), stir, and add 36% acetic acid Solution until the pH value of the solution is 4.0-4.5, mix evenly, add to the ethanol suspension of graphene oxide, and continue to ultrasonicate the system for 30 minutes. The system was transferred to an 80°C constant temperature oil bath for condensing and reflux for 4 hours. Then the reaction system was vacuum filtered, and the filter cake was washed twice with 100 ml of distilled water, and then washed three times with 100 ml of ethanol. The obtained modified graphene oxide was scraped off from the filter paper, fully dried and then weighed; dispersed in an ethanol solution to prepare a 2 mg/ml graphene oxide ethanol suspension for use.

3) Preparation of KH-570 modified graphene loaded sponge. Cut the sponge into blocks of equal length, width and height, and ultrasonically clean it in ethanol solution, then rinse the sponge with deionized water, and dry it in an oven at 60°C; soak the sponge in 2mg/ml GO suspension for 1h, then slowly Ammonia solution was dropped into the GO suspension until the pH was 9, and then GO was reduced with hydrazine hydrate at 95 °C for 1.5 h; the sponge was taken out, washed with deionized water, and dried in a vacuum oven at 30 °C for 24 h, that is The reduced GO, that is, the modified graphene-coated PU sponge, can be obtained.

Embodiment two:

1) Preparation of graphene oxide (GO). The main method is to add 2g of natural flake graphite to a 500mL beaker in an ice-water bath, then add 46mL of concentrated H ₂ SO ₄ (98%), add 1g of NaNO ₃ , control the temperature below 20°C, and add 6g of KMnO while stirring. _4. Raise the temperature to 35~36°C, keep the solution at this temperature for 1.5 hours, at this time, gas will be released; slowly add 92mL deionized water into the mixture, then raise the temperature of the water bath to 98°C, and keep it there 15min to increase the oxidation degree of GO; dilute the mixed solution with 280mL deionized water, and slowly add 6mL 30% H ₂ O ₂ solution to the above solution, if no bright yellow is formed, continue to drop until bright yellow is formed , the mixture was suction filtered or centrifuged, washed with 5% HCl solution several times until no SO ₄ ^2- was detected with BaCl ₂ , then washed with deionized water several times to remove the acid, and the obtained filtered block was °C, dried and weighed for later use.

2) Preparation of KH-560 modified graphene oxide (Lv Xiang, 2011). Disperse 100mg of graphene in 100ml of absolute ethanol, add 2ml of water, 5ml of acetic acid and 10mg of KH-560 (the ratio of silane coupling agent to graphene is 7:100), ultrasonically uniform and react at 80°C for 4h, the obtained The final product is KH-560 modified graphene after being fully dried and reduced in an ethanol system. The lipophilicity of modified graphene is stronger than that of unmodified graphene, but compared with KH-570, its dosage is increased, and the reduction effect is relatively low, and since KH-560 modified graphene has not been loaded with sponge for oil absorption measurement , so its oil-absorbing effect is unknown.

Example Three: Determination of Hydrophobic and Lipophilic Effects of KH-570 Modified Graphene Loaded Polyurethane Sponge

1) Take eight equal parts of the sponge loaded with KH-570 modified graphene (same shape and thickness, about 1g), take any three parts and weigh them respectively, put them on the water surface for 5 minutes, and remove them to the net in time after the adsorption is saturated. Stand on the rack for 1 min, weigh and calculate the water absorption rate of the modified sponge; among them, as a control group, weigh a piece of original sponge and put it on the water surface for 5 min, then remove it to the grid rack in time, let it stand for 1 min, and weigh it. And calculate the water absorption of the original sponge.

2) Take another three weighed sponges and put them on the oil surface for 5 minutes. After the adsorption is saturated, move them to the grid in time, let them stand for 1 minute, weigh and calculate the oil absorption rate of the modified sponges; at the same time, as a control group, Put a piece of original sponge directly on the oil surface for 5 minutes, remove it to the grid rack in time after its adsorption is saturated, let it stand for 1 minute, weigh and calculate the oil absorption rate of the original sponge.

3. Determination results of hydrophobic and lipophilic effect of KH-570 modified graphene loaded polyurethane sponge:

The water absorption rate of the modified sponge=(W ₂ -W ₁ )/W ₁ , the water absorption rate of the original sponge=(m ₂ -m ₁ )/m ₁ ;

The oil absorption rate of the modified sponge=(W ₃ -W ₁ )/W ₁ , the oil absorption rate of the original sponge=(m ₃ -m ₁ )/m ₁ ;

Water absorption rate of modified sponge = water absorption rate/t, oil absorption rate of modified sponge = oil absorption rate/t;

Water absorption rate of original sponge = water absorption rate/t, oil absorption rate of original sponge = oil absorption rate/t;

Among them, W ₁ = modified sponge weight (g), W ₂ = modified sponge + water absorption (g), m ₁ = unmodified sponge weight (g), m ₂ = unmodified sponge + water absorption (g ), W ₃ = modified sponge + oil absorption (g), m ₃ = unmodified sponge + oil absorption (g), t is adsorption time (g).

The water absorption and oil absorption of the sponge are shown in Table 1.

Table 1 The water absorption and oil absorption of the new sponge material prepared

sample Water absorption (g/g) Water absorption rate (g/s) Oil absorption (g/g) Oil absorption rate (g/s) original sponge 34.78 0.10 1.72 0.02 34.69 0.12 1.59 0.02 Modified sponge 1.06 0.09 0.04 0.01 37.89 0.15 1.50 0.02

It can be seen that the modified graphene-loaded polyurethane sponge of the present invention is indeed a material with superhydrophobicity and superoleophilic properties, with good effect and high application value. the

Claims (3)

1. a modified graphene-loaded polyurethane sponge, characterized in that the polyurethane sponge is loaded with a modified graphene coating on the surface of the polyurethane sponge, and the coating thickness is 0.5 ~ 1.0mm; the modified graphene The graphene surface is coated with a silane coupling agent, wherein the mass ratio of the silane coupling agent to graphene is 1:100. 2. the preparation method of modified graphene-loaded polyurethane sponge according to claim 1 is characterized in that described silane coupling agent has: γ-aminopropyltriethoxysilane (KH-550), γ- Glycidyloxypropyltrimethoxysilane (KH-560) or γ-methacryloxypropyltrimethoxysilane (KH-570). 3. a method for preparing modified graphene-loaded polyurethane sponge according to claim 1 or 2, is characterized in that the concrete steps of the method are: a. dissolving graphite oxide in absolute ethanol to prepare a suspension with a concentration of 2mg/ml; b. Mix the silane coupling agent, distilled water and absolute ethanol in a volume ratio of 1:1:18, adjust the pH value of the solution to 4.0~4.5, and then add it to the suspension obtained in step a to make graphite oxide and The mass ratio of the silane coupling agent is 100:1; reflux reaction for 4 hours; then suction filtration, the filter cake is washed with distilled water, and then washed with ethanol, the obtained modified graphene oxide is scraped off the filter paper, fully dried and weighed ; Dispersed in ethanol solution, made into 2mg/ml graphene oxide ethanol suspension, reserved for use; c. Immerse the cleaned polyurethane sponge in the suspension obtained in step b for 1 hour, then adjust the pH to 9, and then reduce the graphene oxide with hydrazine hydrate at 95°C for 1.5 hours; take out the sponge and wash it with deionized water , and dry to obtain the modified graphene-loaded polyurethane sponge.