阅读说明：本技术 一种可用于油包水乳液分离的多层泡沫镍复合材料的制备方法 (Preparation method of multilayer foamed nickel composite material for water-in-oil emulsion separation ) 是由 郭志光 王忆 于 2021-06-23 设计创作，主要内容包括：本发明公开一种可用于油包水乳液分离的多层泡沫镍复合材料的制备方法,该方法以海绵状多孔泡沫镍为载体,超疏水性纳米碳粉为填充物,疏水性聚二甲基硅氧烷为粘结剂,通过简单的悬浮液浸没法与加热固化法制备了单层超疏水泡沫镍复合材料,再使用压机将单层压制成具有高孔隙率和多级粗糙结构的多层复合材料用于油包水乳液分离。该微纳结构表面在空气中和油下均具有良好的超疏水特性,另外,采用该多层复合材料制得的多层高效油包水乳液分离膜在高效分离乳液的过程中表现出出色的化学稳定性、机械抗拉伸性和耐磨性,可重复多次使用。(The invention discloses a preparation method of a multilayer foam nickel composite material for water-in-oil emulsion separation, which takes spongy porous foam nickel as a carrier, super-hydrophobic nano carbon powder as a filler and hydrophobic polydimethylsiloxane as a binder, prepares a single-layer super-hydrophobic foam nickel composite material by a simple suspension immersion method and a heating curing method, and then prepares the multilayer composite material with high porosity and a multistage coarse structure for water-in-oil emulsion separation by using a press to perform single lamination. The surface of the micro-nano structure has good super-hydrophobic characteristics in air and under oil, and in addition, the multilayer high-efficiency water-in-oil emulsion separation membrane prepared from the multilayer composite material shows excellent chemical stability, mechanical tensile resistance and wear resistance in the process of high-efficiency emulsion separation, and can be repeatedly used.)

1. A preparation method of a multilayer foamed nickel composite material for water-in-oil emulsion separation is characterized by comprising the following steps:

A. preparation in the early stage of the experiment: cutting the foamed nickel to a proper size, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel clean by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use;

B. suspension preparation: adding a certain amount of carbon nano-particles CNPs, polydimethylsiloxane PDMS and a curing agent into n-hexane, and carrying out ultrasonic treatment for 1h at the frequency of 30KHz to form a stable suspension and storing the suspension for later use;

C. preparing a single-layer foamed nickel composite material: soaking the cleaned and dried foam nickel chips in the step A into the suspension obtained in the step B, standing at room temperature until the solvent is evaporated to dryness, uniformly depositing a mixture of carbon nano-particles CNPs and polydimethylsiloxane PDMS in the interior and on the surface of the foam nickel, and then placing in a muffle furnace at 100 ℃ for 1h for curing to obtain a single-layer foam nickel composite material;

D. preparing a multilayer foamed nickel composite material: and C, pressing the single-layer foam nickel composite material prepared in the step C into the multilayer foam nickel composite material NF/CNP-PDMS with a certain thickness by using a press machine.

2. The method for preparing a multi-layered foamed nickel composite material for water-in-oil emulsion separation as claimed in claim 1, wherein: in step a, the foam nickel is cut to a suitable size: the length and width were 3X 3 cm.

3. The method for preparing a multi-layered foamed nickel composite material for water-in-oil emulsion separation as claimed in claim 1, wherein: in the step B, the mass percentage ratio of the carbon nano particles CNPs, the polydimethylsiloxane PDMS, the curing agent and the normal hexane is as follows: 0.2%: 1.9%: 0.2%: 97.7 percent.

4. The method for preparing a multi-layered foamed nickel composite material for water-in-oil emulsion separation as claimed in claim 1, wherein: in the step B, the curing agent used is 184 silicon rubber, which reacts with the end group of the polydimethylsiloxane PDMS to function as an adhesive.

5. The method for preparing a multi-layered foamed nickel composite material for water-in-oil emulsion separation as claimed in claim 1, wherein: and D, when the multilayer foam nickel composite material is pressed, selecting 5 single-layer foam nickel composite material chips, and pressing the chips to the thickness of 2mm to obtain the NF/CNP-PDMS composite material with the size of 3cm multiplied by 2 mm.

6. The method for preparing a multi-layered foamed nickel composite material for water-in-oil emulsion separation as claimed in claim 1, wherein: further comprising step e. water-in-oil emulsion separation performance test:

(1) four water-in-oil emulsions were prepared: mixing water and oil in a ratio of 1: 100, wherein the oil is respectively selected from xylene, dichloromethane, n-hexane and gasoline to prepare four emulsions, Span 80 is used as a stabilizer of the four emulsions, the dosage is 1.5mg/mL, and then the four emulsions are subjected to ultrasonic treatment for 1h at 40KHz to prepare four water-in-oil emulsions, so that all the emulsions can be stabilized for more than one week;

(2) the prepared multilayer foam nickel composite material NF/CNP-PDMS is fixed in a suction filtration device, the interface is sealed, then the prepared four water-in-oil emulsions are respectively poured on a separation membrane, the emulsions are separated only under the driving of gravity, and the average separation efficiency is over 95 percent.

Technical Field

The invention belongs to the technical field of preparation of three-dimensional water-in-oil emulsion separation membranes, and particularly relates to a method for preparing a multilayer super-hydrophobic foamed nickel composite separation material with chemical stability and mechanical stability.

Background

With the development of society, a large amount of oily sewage is generated in industrial manufacturing and daily life, and untreated oily sewage causes serious pollution to the environment, so that the separation of oil-water mixture, especially emulsified oil-water mixture, is a serious and must-overcome challenge. Membrane technology is considered to be the most effective method for treating oily wastewater due to its high separation efficiency and simple operation process. However, when the membrane technology is used for separating oily wastewater, in addition to optimizing separation efficiency and flux, the membrane pollution problem caused by adsorption of oil droplets and other organic small molecules on the surface of the membrane needs to be solved. Therefore, the oil-water separation material can be designed by utilizing the super-wetting behavior of the solid surface.

The multilayer NF/CNP-PDMS composite material with the super-hydrophobic characteristic is prepared by simple and low-cost methods of immersion, heating curing and pressing. The membrane can separate various water-in-oil emulsions only under the action of gravity, and the average separation efficiency is as high as 95%. And the filling of the carbon nano particles-polydimethylsiloxane (CNP-PDMS) greatly improves the chemical stability and mechanical stability of the foamed nickel. These characteristics are beneficial for the research of stable and efficient oil super-hydrophobic self-cleaning materials and emulsion separation equipment.

Disclosure of Invention

The invention aims to provide a simple, convenient, easy, economical and efficient method for preparing a multi-layer super-hydrophobic foamed nickel water-in-oil emulsion separation material with chemical stability and mechanical stability. The preparation method is characterized in that foam Nickel (NF) with excellent mechanical properties is used as a filter carrier, Carbon Nano Particles (CNPs) with low surface energy and a micro-nano structure are used as fillers, Polydimethylsiloxane (PDMS) with low surface energy and hydrophobicity is used as a binder, and the preparation of the multilayer high-efficiency water-in-oil emulsion separation membrane is realized by simple suspension immersion, heating curing and pressing methods.

The technical scheme for realizing the purpose of the invention is as follows:

a preparation method of a multilayer foamed nickel composite material for water-in-oil emulsion separation is characterized by comprising the following steps:

A. preparation in the early stage of the experiment: cutting the foamed nickel to a proper size, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel clean by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use;

B. suspension preparation: adding a certain amount of carbon nano-particles CNPs, polydimethylsiloxane PDMS and a curing agent into n-hexane, and carrying out ultrasonic treatment for 1h at the frequency of 30KHz to form a stable suspension and storing the suspension for later use;

C. preparing a single-layer foamed nickel composite material: soaking the cleaned and dried foam nickel chips in the step A into the suspension obtained in the step B, standing at room temperature until the solvent is evaporated to dryness, uniformly depositing a mixture of carbon nano-particles CNPs and polydimethylsiloxane PDMS in the interior and on the surface of the foam nickel, and then placing in a muffle furnace at 100 ℃ for 1h for curing to obtain a single-layer foam nickel composite material;

D. preparing a multilayer foamed nickel composite material: and C, pressing the single-layer foam nickel composite material prepared in the step C into the multilayer foam nickel composite material NF/CNP-PDMS with a certain thickness by using a press machine.

Further, in step a, the foam nickel is cut to a suitable size: the length and width were 3X 3 cm.

Further, in the step B, the mass percentage ratio of the carbon nanoparticles CNPs, the polydimethylsiloxane PDMS, the curing agent and the n-hexane is: 0.2%: 1.9%: 0.2%: 97.7 percent.

Further, in step B, the curing agent used is 184 silicone rubber, which reacts with the end group of the polydimethylsiloxane PDMS to function as an adhesive.

Further, in the step D, when the multilayer foamed nickel composite material is pressed, 5 single-layer foamed nickel composite material chips are selected and pressed to be 2mm thick, and the NF/CNP-PDMS composite material with the size of 3cm multiplied by 2mm is obtained.

Further, the method also comprises a step E. water-in-oil emulsion separation performance test:

(1) four water-in-oil emulsions were prepared: mixing water and oil in a ratio of 1: 100, wherein the oil is respectively selected from xylene, dichloromethane, n-hexane and gasoline to prepare four emulsions, Span 80 is used as a stabilizer of the four emulsions, the dosage is 1.5mg/mL, and then the four emulsions are subjected to ultrasonic treatment for 1h at 40KHz to prepare four water-in-oil emulsions, so that all the emulsions can be stabilized for more than one week;

(2) the prepared multilayer foam nickel composite material NF/CNP-PDMS is fixed in a suction filtration device, the interface is sealed, then the prepared four water-in-oil emulsions are respectively poured on a separation membrane, the emulsions are separated only under the driving of gravity, and the average separation efficiency is over 95 percent.

The invention has the beneficial effects that: compared with the prior art, the invention has the advantages that:

1. the preparation process is simple and easy to implement, does not relate to harmful substances such as fluorine-containing modifier and the like in the preparation process, and accords with the green chemical principle.

2. The prepared super-hydrophobic emulsion separation membrane has high separation efficiency, and can separate various water-in-oil emulsions only under the action of gravity.

3. The prepared emulsion separation membrane has excellent chemical stability and mechanical stability and can be repeatedly used.

4. The prepared three-dimensional multilayer emulsion separation membrane can change the number of layers so as to meet the separation requirements of different emulsions.

Drawings

FIG. 1 is an electron micrograph (a) of original foam nickel magnified 150 times, an electron micrograph (b) of NF/CNP-PDMS composite magnified 150 times, an electron micrograph (c) of NF/CNP-PDMS composite magnified 20000 times, and an electron micrograph (d) of NF/CNP-PDMS composite magnified 80000 times in example 1 of the present invention.

FIG. 2 shows the water contact angle (a) of the original foam nickel, the water contact angle (b) of the NF/CNP-PDMS composite material, the water contact angle (c) of the NF/CNP-PDMS composite material under xylene oil, and the wettability (d-g) of xylene, dichloromethane, n-hexane and gasoline on the NF/CNP-PDMS composite material in example 1 of the present invention.

FIG. 3 is an X-ray photoelectron spectrum (a) of the original foam nickel and NF/CNP-PDMS composite material in example 1 of the present invention, a Fourier transform infrared spectrum (b) of the carbon nanoparticles and NF/CNP-PDMS composite material, and an X-ray energy spectrum analysis (C) of Ni, Si, C elements in the NF/CNP-PDMS composite material.

FIG. 4 is a graph showing the water content of the filtrate after separation of the water-in-oil emulsion and the emulsion separation efficiency (a), the flux of the emulsion separation (b), and the water droplet distribution pattern (c-f) in the water-in-oil emulsion (xylene, methylene chloride, n-hexane, gasoline) before and after the filtration in example 1 according to the present invention.

FIG. 5 is a graph showing the water content of the filtrate and the separation efficiency of the xylene water-in-oil emulsion in ten separation cycles in example 2 of the present invention.

FIG. 6 is a graph of contact angle and droplet morphology of liquids with different pH values on the membrane surface in example 3 of the present invention (a), and change in contact angle of membranes immersed in deionized water and 3.5 wt% NaCl solution over six hours (b).

Fig. 7 is a stress-strain curve (a) of original foam nickel, foam nickel after pressing, and NF/CNP-PDMS composite material in example 4 of the present invention, a change (b) of a contact angle value of a separation membrane in a 50-wear cycle test, and a separation efficiency value (c) of the separation membrane to separate four emulsions after wear.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples. Various changes or modifications may be effected therein by one skilled in the art and such equivalents are intended to be within the scope of the invention as defined by the claims appended hereto.

Example 1

(1) Preparation in the early stage of the experiment:

cutting the foamed nickel to 3 multiplied by 3cm, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use.

(2) Suspension preparation:

0.1g of Carbon Nanoparticles (CNPs), 1g of Polydimethylsiloxane (PDMS) and 0.1g of a curing agent (184 silicone rubber) were added to 50g of n-hexane, and sonicated for 1h using a frequency of 30KHz to form a stable suspension and stored for use.

(3) Preparation of single-layer foamed nickel composite material:

immersing the cleaned and dried foam nickel slices into the suspension, and standing at room temperature until the solvent is evaporated to dryness, and uniformly depositing a mixture of Carbon Nanoparticles (CNPs) and Polydimethylsiloxane (PDMS) in and on the surface of the foam nickel. And then placing the composite material in a muffle furnace at 100 ℃ for 1h, and curing the composite material to obtain the single-layer super-hydrophobic foam nickel composite surface.

(4) Preparation of multilayer foamed nickel composite:

5 sheets of the single-layer foamed nickel composite material prepared in the step are taken and pressed into a multilayer foamed nickel composite material (NF/CNP-PDMS) with the thickness of 2mm and the size of 3cm multiplied by 2mm by a press machine.

(5) Water-in-oil emulsion separation performance:

the prepared multilayer nickel foam composite material (NF/CNP-PDMS) is fixed in a suction filtration device, and the interface is sealed. Water and oil (xylene, dichloromethane, n-hexane, gasoline) were mixed at a ratio of 1: 100 volume ratio, Span 80 as a stabilizer for the four emulsions at a dose of 1.5mg/mL, and then sonicated at 40KHz for 1h to prepare four water-in-oil emulsions. The four water-in-oil emulsions were poured onto separate membranes and the emulsions were separated only under the drive of gravity. Then, the content of water in the filtrate after separation was measured by using a karl fischer moisture titrator, as shown in fig. 4, the obtained average separation efficiency was 95% or more.

Example 2

(1) Preparation in the early stage of the experiment:

cutting the foamed nickel to 3 multiplied by 3cm, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use.

(2) Suspension preparation:

0.1g of Carbon Nanoparticles (CNPs), 1g of Polydimethylsiloxane (PDMS) and 0.1g of a curing agent (184 silicone rubber) were added to 50g of n-hexane, and sonicated for 1h using a frequency of 30KHz to form a stable suspension and stored for use.

(3) Preparation of single-layer foamed nickel composite material:

immersing the cleaned and dried foam nickel slices into the suspension, and standing at room temperature until the solvent is evaporated to dryness, and uniformly depositing a mixture of Carbon Nanoparticles (CNPs) and Polydimethylsiloxane (PDMS) in and on the surface of the foam nickel. And then placing the composite material in a muffle furnace at 100 ℃ for 1h, and curing the composite material to obtain the single-layer super-hydrophobic foam nickel composite surface.

(4) Preparation of multilayer foamed nickel composite:

5 prepared single-layer foamed nickel composite materials are taken and pressed into a multilayer foamed nickel composite material (NF/CNP-PDMS) with the thickness of 2mm and the size of 3cm multiplied by 2mm by a press machine.

(5) Water-in-oil emulsion separation stability:

fixing the prepared multilayer foam nickel composite material (NF/CNP-PDMS) in a suction filtration device, sealing an interface, taking a xylene water-in-oil emulsion as an example, after each emulsion separation, repeatedly cleaning a separation membrane with ethanol and water and drying to continue the next separation, as shown in FIG. 5, wherein after ten separation cycles, the average separation efficiency is more than 97%.

Example 3

(1) Preparation in the early stage of the experiment:

cutting the foamed nickel to 3 multiplied by 3cm, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use.

(2) Suspension preparation:

0.1g of Carbon Nanoparticles (CNPs), 1g of Polydimethylsiloxane (PDMS) and 0.1g of a curing agent (184 silicone rubber) were added to 50g of n-hexane, and sonicated for 1h using a frequency of 30KHz to form a stable suspension and stored for use.

(3) Preparation of single-layer foamed nickel composite material:

immersing the cleaned and dried foam nickel slices into the suspension, and standing at room temperature until the solvent is evaporated to dryness, and uniformly depositing a mixture of Carbon Nanoparticles (CNPs) and Polydimethylsiloxane (PDMS) in and on the surface of the foam nickel. And then placing the composite material in a muffle furnace at 100 ℃ for 1h, and curing the composite material to obtain the single-layer super-hydrophobic foam nickel composite surface.

(4) Preparation of multilayer foamed nickel composite:

5 sheets of the single-layer foamed nickel composite material prepared in the step are taken and pressed into a multilayer foamed nickel composite material (NF/CNP-PDMS) with the thickness of 2mm and the size of 3cm multiplied by 2mm by a press machine.

(5) Chemical stability of emulsion separation membranes:

and 5 mul of liquid drops with different pH values are dropped on the surface of the separation membrane, as shown in figure 6a, the liquid drops with different pH values are all spherical on the surface of the membrane, and the contact angle is more than 145 degrees. FIG. 6b shows that the separation membrane was immersed in deionized water and 3.5 wt% NaCl solution, respectively, for six hours, and the water contact angle value was measured every hour, which was stable with time without large fluctuation.

Example 4

(1) Preparation in the early stage of the experiment:

cutting the foamed nickel to 3 multiplied by 3cm, ultrasonically cleaning the foamed nickel in ethanol for 30min, then washing the foamed nickel by deionized water, and putting the cleaned foamed nickel into an oven for drying for later use.

(2) Suspension preparation:

0.1g of Carbon Nanoparticles (CNPs), 1g of Polydimethylsiloxane (PDMS) and 0.1g of a curing agent (184 silicone rubber) were added to 50g of n-hexane, and sonicated for 1h using a frequency of 30KHz to form a stable suspension and stored for use.

(3) Preparation of single-layer foamed nickel composite material:

immersing the cleaned and dried foam nickel slices into the suspension, and standing at room temperature until the solvent is evaporated to dryness, and uniformly depositing a mixture of Carbon Nanoparticles (CNPs) and Polydimethylsiloxane (PDMS) in and on the surface of the foam nickel. And then placing the composite material in a muffle furnace at 100 ℃ for 1h, and curing the composite material to obtain the single-layer super-hydrophobic foam nickel composite surface.

(4) Preparation of multilayer foamed nickel composite:

5 sheets of the single-layer foamed nickel composite material prepared in the step are taken and pressed into a multilayer foamed nickel composite material (NF/CNP-PDMS) with the thickness of 2mm and the size of 3cm multiplied by 2mm by a press machine.

(5) Mechanical stability of the emulsion separation membrane:

the tensile properties of the separation membrane were measured using an electronic universal tester, and the initial length and the stretching speed of the separation membrane were set to 25mm and 2.0mm/min, respectively. As shown in fig. 7a, it can be seen from the stress-strain curve of the original nickel foam, the pressed nickel foam, and the NF/CNP-PDMS composite material that the blank nickel foam is filled with the carbon nanoparticle-polydimethylsiloxane (CNP-PDMS), so that the interlayer bonding defects and interlayer gaps are reduced, the maximum stress (breaking strength) and the maximum strain (breaking elongation) are both significantly increased, and the tensile property is improved. The separation membrane was placed on a flat sandpaper (mesh number 800) surface, a weight of 50g was placed over the separation membrane, 10cm was pulled along the scale under an external pulling force in a horizontal direction, ten sets were measured for each five abrasion cycles, and the contact angle of the separation membrane after each set of abrasion tests was recorded, as shown in fig. 7b, the water contact angle of the membrane surface was maintained at around 150 °. After the end of the ten abrasion cycles, the four water-in-oil emulsions (xylene, dichloromethane, n-hexane, gasoline) were separated using separation membranes, obtaining an average separation efficiency of more than 95% (fig. 7 c).

To summarize: the method takes spongy porous foamed nickel as a carrier, super-hydrophobic nano carbon powder as a filler and hydrophobic polydimethylsiloxane as a binder, prepares a single-layer super-hydrophobic foamed nickel composite material by a simple suspension immersion method and a heating curing method, and then prepares a multi-layer composite material with high porosity and a multi-stage coarse structure by single lamination by using a press for water-in-oil emulsion separation. The surface of the micro-nano structure has good super-hydrophobic characteristics in air and under oil, and in addition, the multilayer high-efficiency water-in-oil emulsion separation membrane prepared from the multilayer composite material shows excellent chemical stability, mechanical tensile resistance and wear resistance in the process of high-efficiency emulsion separation, and can be repeatedly used.

Finally, it should be noted that the above-mentioned contents are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, and that the simple modifications or equivalent substitutions of the technical solutions of the present invention by those of ordinary skill in the art can be made without departing from the spirit and scope of the technical solutions of the present invention.