阅读说明：本技术 一种黑体材料的制备方法及其应用 (Preparation method and application of black body material ) 是由 俞书宏 赵浩雨 于 2019-11-11 设计创作，主要内容包括：本发明提供了一种黑体材料的制备方法,包括以下步骤：A)将苯酚类化合物和醛类化合物,在软模板胶束的溶液中进行热聚合,聚合过程中伴随相分离过程,制备得到酚醛树脂；所述酚醛树脂的纤维排列形成三维桁架状结构；所述软模板胶束包裹于所述纤维内部,且排列方向与纤维平行：B)对酚醛树脂进行高温处理,使软模板胶束热解完全,在酚醛树脂纤维中形成平行排列的孔结构,得到多孔碳基材料；C)利用极性亲水修饰剂对多孔碳基材料进行亲水性修饰,使材料由疏水性变为亲水性,得到亲水多孔碳基材料；D)利用表层修饰技术在亲水多孔碳基材料的上表层修饰含氟硅烷,使材料的上表层呈现超疏水性,得到界面光热转化水蒸发黑体材料。(The invention provides a preparation method of a blackbody material, which comprises the following steps: A) thermally polymerizing a phenol compound and an aldehyde compound in a solution of a soft template micelle, and preparing phenolic resin along with a phase separation process in the polymerization process; the fibers of the phenolic resin are arranged to form a three-dimensional truss-like structure; the soft template micelle is wrapped inside the fiber, and the arrangement direction is parallel to the fiber: B) carrying out high-temperature treatment on the phenolic resin to completely pyrolyze the soft template micelle and form a parallel pore structure in phenolic resin fibers to obtain a porous carbon-based material; C) hydrophilic modification is carried out on the porous carbon-based material by utilizing a polar hydrophilic modifier, so that the material is changed from hydrophobicity to hydrophilicity, and the hydrophilic porous carbon-based material is obtained; D) and modifying the upper surface layer of the hydrophilic porous carbon-based material with fluorine-containing silane by utilizing a surface layer modification technology to enable the upper surface layer of the material to present super-hydrophobicity, thereby obtaining the interface photo-thermal conversion water evaporation black body material.)

1. The preparation method of the blackbody material is characterized by comprising the following steps of:

A) thermally polymerizing a phenol compound and an aldehyde compound in a solution of a soft template micelle, wherein a phase separation process is accompanied in the polymerization process to prepare phenolic resin;

the fibers of the phenolic resin are arranged to form a three-dimensional truss-like structure; the soft template micelle is wrapped inside the fiber, and the arrangement direction is parallel to the fiber:

B) carrying out high-temperature treatment on the phenolic resin obtained in the step A), so that the micelle of the soft template is completely pyrolyzed, and forming a pore structure which is arranged in parallel in phenolic resin fibers to obtain a porous carbon-based material;

C) carrying out hydrophilic modification on the porous carbon-based material obtained in the step B) by using a polar hydrophilic modifier to change the hydrophobicity of the material into hydrophilicity so as to obtain a hydrophilic porous carbon-based material;

D) and modifying the upper surface layer of the hydrophilic porous carbon-based material with fluorine-containing silane by utilizing a surface layer modification technology to enable the upper surface layer of the material to present super-hydrophobicity, thereby obtaining the interface photo-thermal conversion water evaporation black body material.

2. The method according to claim 1, wherein the phenol compound is resorcinol; the aldehyde compound is formaldehyde.

3. The method of claim 1, wherein the soft template micelles are 1,3, 5-trimethylbenzene and benzyl alcohol-assisted F127, soft template micelles formed in an acidic isopropanol solution.

4. The preparation method according to claim 1, wherein the high-temperature treatment is specifically:

ventilating at 150-250 ℃ for 1-3 h; then heating to 700-900 ℃ at the heating rate of 1-3 ℃/min, and pyrolyzing for 0.5-1.5 h.

5. The method of claim 1, wherein the polar hydrophilic modifier is dopamine.

6. The method according to claim 1, wherein step C) is in particular:

dipping the porous carbon-based material obtained in the step B) into a mixed solution of trimethylol methylamine and dopamine, and then drying.

7. The method according to claim 1, wherein the surface layer modification technique is a printing technique, a spraying technique, or a magnetron sputtering technique.

8. The method according to claim 1, wherein the fluorine-containing silane is 1H,1H,2H, 2H-perfluorodecyltriethoxysilane or pentadecafluorooctane.

9. The blackbody material prepared by the preparation method of any one of claims 1 to 8 is applied to the fields of seawater desalination and sewage treatment.

Technical Field

The invention relates to the technical field of material chemistry, in particular to a preparation method and application of a black body material.

Background

Increasingly serious shortage of fresh water not only seriously affects the development of ecosystems and society in arid areas, but also seriously affects heavily polluted areas and high salinity areas. During the last decades, a great deal of research has been focused on finding reliable new methods to purify water at lower cost and with less energy. Inspired by the ubiquitous hydrologic cycle of nature, solar interfacial photothermal conversion (STC) evaporation, in which distilled water is directly collected by solar energy, has been considered as one of the most economical and sustainable technologies for desalination of sea water and reduction of sewage discharge. In particular, proposals for photothermal conversion interface evaporation systems have been achieved with efficiencies in excess of 90%, validating their promise for practical fresh water collection.

However, long-term stable photothermal conversion interfacial water evaporation in brine (or contaminated water) remains challenging because the salt (or solute) will remain and crystallize (or accumulate) as water evaporates at the interface. Although many high performance nanotechnologies based on the principle of evaporation have successfully solved the problem of salt tolerance, there are still some problems that require further exploration based on salt tolerant interface (or structure) design, through which more practical evaporators are developed.

Furthermore, without additional concentrators, the theoretical evaporation rate under ambient solar energy is limited and cannot meet the enormous demand for water, which also limits its wide application. Although polymers, hydrogels and carbonized sponges achieve high evaporation rates, far exceeding the theoretical values, due to the low enthalpy of vaporization of water, there is still a need to explore further more materials to achieve high rate water evaporation techniques with excellent properties, such as environmental resistance and temperature regulation.

The current mainstream black body materials mainly comprise black polymers, plasmons and carbon-based absorbers. Wherein the swelling behavior of the polymer makes it less drought resistant; the plasma absorber is easily destroyed in form, and the practical photo-thermal water evaporation method still has the challenge. In view of the remarkable properties of natural broadband solar absorption, the resistance to thermal acid/base and ultraviolet light, and the excellent thermal conversion performance, carbon-based absorbents are considered to be one of the best candidates for practical high-efficiency photothermal conversion water evaporation. Moreover, their economy, sustainability and good processing characteristics contribute to their widespread use. However, the inherent hydrophobicity and poor thermal insulation properties of carbon-based materials are not suitable for water transport and efficient thermal management.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a method for preparing a black body material and an application thereof, wherein the black body material is used for interface photothermal conversion water evaporation, and has high solar energy absorption capacity, high water transport capacity, low thermal conductivity and excellent salt tolerance.

In order to solve the technical problems, the invention provides a preparation method of a black body material, which comprises the following steps:

A) thermally polymerizing a phenol compound and an aldehyde compound in a solution of a soft template micelle, wherein a phase separation process is accompanied in the polymerization process to prepare phenolic resin;

the fibers of the phenolic resin are arranged to form a three-dimensional truss-like structure; the soft template micelle is wrapped inside the fiber, and the arrangement direction is parallel to the fiber:

B) carrying out high-temperature treatment on the phenolic resin obtained in the step A), so that the micelle of the soft template is completely pyrolyzed, and forming a pore structure which is arranged in parallel in phenolic resin fibers to obtain a porous carbon-based material;

C) carrying out hydrophilic modification on the porous carbon-based material obtained in the step B) by using a polar hydrophilic modifier to change the hydrophobicity of the material into hydrophilicity so as to obtain a hydrophilic porous carbon-based material;

D) and modifying the upper surface layer of the hydrophilic porous carbon-based material with fluorine-containing silane by utilizing a surface layer modification technology to enable the upper surface layer of the material to present super-hydrophobicity, thereby obtaining the interface photo-thermal conversion water evaporation black body material.

The invention is inspired by lotus flower morphology, and the bionic evaporator is prepared and has a double-pore structure and wettability with difference of two surfaces. Each truss structure comprises macropores formed by three-dimensionally interconnected truss structures and parallel lotus-like-hole-shaped mesopores inside fibers, so that the self-floating effect is realized by reducing the density, the vapor is dispersed, and the truss structure has excellent thermal regulation performance and firm mechanical performance. The lower surface of the material has hydrophilicity, and the upper surface has hydrophobicity, and experimental results show that the hydrophilic macropores have high water transmission capability, and the hydrophobic macropore layer on the upper surface cuts off the transmission of water and prevents salt from accumulating on the surface, thereby being beneficial to the stability of long-term and efficient photo-thermal conversion water evaporation. Due to the special structure of the two types of pore channels and the wettability difference of the two surfaces, the blackbody material prepared by the invention has lower water interface vaporization enthalpy than grinding and single-wettability carbon. It is worth noting that lower water interface evaporation enthalpy is beneficial for achieving higher evaporation rate with the same photothermal conversion and heat dissipation efficiency.

The above materials are used for long-term photothermal conversion and higher rate evaporation in brine (1.597kg m)^-2h^-1). The black material prepared by the invention not only has high-efficiency solar energy absorption, rapid water transmission capability and low thermal conductivity, but also has excellent salt resistance and tolerance. This shows the excellent resistance of the biomimetic photothermal conversion water evaporation blackbody material to sewage treatment under severe conditions. Further outdoor experiments also demonstrate its reasonable promise for distilled water.

The invention firstly utilizes a micelle template method and a phase separation technology to synthesize the phenolic resin with a three-dimensional truss structure.

The invention takes phenol compounds and aldehyde compounds as raw materials.

The phenolic compound is preferably resorcinol; the aldehyde compound is preferably formaldehyde.

The phenol compound and the aldehyde compound are thermally polymerized in a solution of soft-template micelles.

The soft template micelle of the present invention is preferably a soft template micelle formed of surfactant molecules.

The soft template micelle is further preferably a soft template micelle formed by 1,3, 5-trimethylbenzene and benzyl alcohol assisted F127 in an acidic isopropanol solution.

In the thermal polymerization process, the finally prepared phenolic resin is accompanied with a phase separation process, and fibers are arranged to form a three-dimensional truss-like structure.

The soft template micelle is wrapped inside the fibers of the phenolic resin, and the arrangement direction of the soft template micelle is parallel to the fibers.

And then, by utilizing the residual quantity difference of the carbonized products, carrying out high-temperature treatment to ensure that the soft template micelle wrapped in the phenolic resin fiber is completely pyrolyzed, forming a lotus-root-like hole-shaped parallel pore structure in the phenolic resin fiber of the truss structure, and changing the whole material from yellow to black.

Preferably, the high-temperature treatment specifically comprises:

ventilating at 150-250 ℃ for 1-3 h; then heating to 700-900 ℃ at the heating rate of 1-3 ℃/min, and pyrolyzing for 0.5-1.5 h.

More preferably, it is specifically:

ventilating at 200 ℃ for 2 h; then heating to 800 ℃ at the heating rate of 2 ℃/min, and pyrolyzing for 1 h.

The high-temperature treatment is preferably performed in an air atmosphere.

After high-temperature treatment, the obtained porous carbon-based material has a double-pore structure, wherein one is a large pore formed by fibers of a truss structure, the pore diameter is 5-20 micrometers, the other is a micropore of a lotus-like pore formed in the fibers, and the pore diameter is preferably 5-10 nanometers.

Then, hydrophilic modification of the phenolic resin is carried out by utilizing a polar hydrophilic modifier, so that the material is changed from hydrophobicity to hydrophilicity, and water transportation can be effectively carried out.

The polar hydrophilic modifier is preferably dopamine.

Preferably, the specific operation steps of the hydrophilic modification are as follows:

dipping the porous carbon-based material obtained in the step B) into a mixed solution of trimethylol methylamine and dopamine, and then drying.

The solvent of the solution is preferably a mixed solvent of water and ethanol.

The soaking time is preferably 24-48 h.

The drying treatment temperature is preferably 50-80 ℃, and the time is preferably 1-3 h.

And finally, modifying the upper surface layer of the material with fluorine-containing silane by a surface layer modification technology to form a hydrophobic structure, so that the salt accumulation in the dissolved salt evaporation process can be effectively avoided.

The surface layer modification technology is preferably a printing and dyeing technology, a spraying technology or a magnetron sputtering technology.

Preferably, the fluorine-containing silane is 1H,1H,2H, 2H-perfluorodecyl triethoxysilane or pentadecafluorooctane.

The black body material obtained by final preparation is a hydrophilic material with a hydrophobic upper surface, the bulk phase has rapid water transportation capability, and the upper surface has salt resistance in the process of evaporation of light and hot water.

The black body material prepared by the invention is a phenolic resin material, fibers of the phenolic resin are arranged to form a three-dimensional truss-shaped structure, and a pore structure with the arrangement direction parallel to the fibers is arranged inside the fibers; the lower surface of the phenolic resin material is hydrophilic, and the upper surface of the phenolic resin material is hydrophobic.

The invention also provides application of the blackbody material prepared by the preparation method in the fields of seawater desalination and sewage treatment.

The invention is inspired by porous roots (lotus roots) of lotus flowers and bilateral lotus leaves in nature, firstly provides a high-efficiency interface photo-thermal conversion water evaporation black body material with bilateral wettability and a double-channel structure, and is used for long-term stable photo-thermal conversion and high-speed water evaporation in saline water.

According to the invention, firstly, the phenolic resin with a three-dimensional truss structure is synthesized by utilizing a soft membrane plate and a phase separation technology, and the high-efficiency interface photothermal conversion water evaporation black body material with two types of pore structures is prepared by further pyrolyzing and modifying dopamine and fluorine-containing silane. Wherein, in the double-pore structure, the macropores have hydrophilicity and are used for the effective water transportation process in the water evaporation process; the lotus-root-like porous micropores have hydrophobicity, and gas in the pore channel is beneficial to heat pipe control in the process of photo-thermal conversion, so that efficient photo-thermal conversion water evaporation is realized. In addition, the material prepared by the invention has two sides, namely the hydrophilicity of the lower layer of the material is used for necessary water transportation, and the hydrophobicity of the upper surface is favorable for salt deposition resistance.

The experimental result shows that the blackbody material prepared by the invention has high-efficiency solar energy absorption capacity (>97%), Water transport Capacity (0.95g mm^-1min^-1) And low thermal conductivity: (<0.12W m^-1K^-1) And the hydrophobic upper surface also has excellent salt resistance. The invention also emphasizes the low water vaporization enthalpy (1846J g) in the conversion material^-1) The positive effect of the method opens up a new way for further developing a high-speed evaporation system. The blackbody material prepared by the invention also has high tolerance, and is the blackbody material which can resist heat, acid, alkali and oxidant (100 ℃, 48 hours) and is reported for the first time. The method has wide application prospect in the fields of seawater desalination, sewage treatment and the like under severe conditions. And has excellent mechanical strength and can maintain the structural characteristics under the extreme condition of 100 ℃.

Drawings

FIG. 1 is a schematic structural diagram of an interface photothermal conversion water evaporation blackbody material prepared by the present invention;

FIG. 2 is a physical diagram of the interface photothermal conversion water evaporation blackbody material prepared by the present invention;

FIG. 3 is an SEM image and a TEM image of a porous carbon material prepared in step 2) of example 1 of the present invention;

FIG. 4 is an XPS energy spectrum of samples prepared in an example of the present invention;

FIG. 5 is a schematic view of the interface photothermal conversion water evaporation blackbody material prepared in the example of the invention floating on the water surface; it can be seen that the lower surface layer of the material is hydrophilic and the upper surface layer is hydrophobic;

FIG. 6 is a UV-VIS-IR absorption spectrum of a sample prepared in an example of the present invention;

FIG. 7 is a vertical water transport test curve for a sample prepared in an example of the present invention;

FIG. 8 is a heat absorption curve of a sample prepared in an example of the present invention;

FIG. 9 is a graph showing the photo-thermal water evaporation rate of the interface photothermal conversion water evaporation blackbody material prepared according to an embodiment of the present invention;

FIG. 10 is a physical diagram of the interfacial photothermal conversion water evaporation blackbody material prepared in accordance with an example of the invention under caustic conditions.

Detailed Description

In order to further illustrate the present invention, the following will describe in detail the preparation method and application of the blackbody material provided by the present invention with reference to examples.