PHOTOTHERMAL EVAPORATION MATERIAL INTEGRATING LIGHT ABSORPTION AND THERMAL INSULATION, PREPARATION APPLICATION THEREOF, USE THEREOF

Abstract

The invention discloses a photothermal evaporation material integrating light absorption and thermal insulation, comprising a heat insulator and a light absorber that covers the external surface of the heat insulator, the light absorber is vertically-oriented graphene, the heat insulator is a graphene foam, and the vertically-oriented graphene and graphene foam are connected by covalent bonds; the light absorber is vertically-oriented graphene whose surface is modified with hydrophilic functional groups. The invention also discloses a method for fabricating the photothermal evaporation material integrating light absorption and thermal insulation. The invention also discloses a solar energy photothermal seawater desalination device and a high-temperature steam sterilization device. The photothermal evaporation material integrating light absorption and thermal insulation overcomes the problem of easy separation between the light absorber and the heat insulator, realizes rapid and efficient photothermal evaporation, and improves the stability and photothermal conversion efficiency of the solar photothermal seawater desalination device and the high-temperature steam sterilization device.

Claims

1. A photothermal evaporation material integrating light absorption and thermal insulation comprises a heat insulator and a light absorber that covers the external surface of the heat insulator, wherein the light absorber is vertically-oriented graphene, the heat insulator is a graphene foam, and the vertically-oriented graphene and graphene foam are connected by covalent bonds; the light absorber is vertically-oriented graphene whose surface is modified with hydrophilic functional groups.

2. The photothermal evaporation material integrating light absorption and thermal insulation according to claim 1, wherein the hydrophilic functional groups are oxygen-containing functional groups.

3. The photothermal evaporation material integrating light absorption and thermal insulation according to claim 1, wherein the absorbance of the light absorber is 90-99%, and the thermal conductivity of the heat insulator is 0.02-0.2 W m−1 K−1.

4. A method for fabricating the photothermal evaporation material integrating light absorption and thermal insulation according to claim 1, comprises the following steps: (1) preparing an aqueous solution of graphene oxide; (2) transferring the aqueous solution of graphene oxide obtained in step (1) to a high temperature and high-pressure reactor for hydrothermal reaction, and cooling to obtain a graphene hydrogel; (3) soaking the graphene hydrogel obtained in step (2) with an ethanol aqueous solution; (4) transferring the graphene hydrogel to a freezing chamber for freezing, and then transferring to a drying chamber for vacuum drying to obtain a graphene foam; (5) placing the obtained graphene foam in a plasma-enhanced chemical vapor deposition reaction chamber, and introducing methane or a mixture of hydrogen and methane; after the chemical vapor deposition reaction, the inert gas is introduced for cooling to obtain the vertically-oriented graphite/graphene foam; (6) exposing the vertically-oriented graphene/graphene foam obtained in step (5) to an ozone environment, and the hydrophilic functional groups are modified on the surface of the vertically-oriented graphene to obtain a photothermal evaporation material integrating light absorption and thermal insulation.

5. The method for fabricating a photothermal evaporation material integrating light absorption and thermal insulation according to claim 4, wherein the aqueous solution of graphene oxide in step (1) further comprises an additive, and the additive comprises sodium tetraborate decahydrate, amine compound or mixtures thereof; the concentration of the graphene oxide is 1-10 g L.sup.−1, the concentration of the sodium tetraborate decahydrate is 0-10 mmol L.sup.−1, the concentration of the amine compound is 0-100 mmol L.sup.−1; and the concentration of the sodium tetraborate decahydrate and the concentration of the amine compound are not 0 at the same time.

6. The method for fabricating a photothermal evaporation material integrating light absorption and thermal insulation according to claim 5, wherein the conditions of hydrothermal reaction in step (2) are: the reaction temperature is 90-180° C.; the reaction time is 6-18 hours.

7. The method for fabricating a photothermal evaporation material integrating light absorption and thermal insulation according to claim 4, wherein in step (5), the flow ratio of the gas mixture of hydrogen and methane is 0-20:1.

8. The method for fabricating a photothermal evaporation material integrating light absorption and thermal insulation according to claim 4, wherein in step (5), the reaction conditions of the chemical vapor deposition reaction are: the synthesis temperature is 500-1000° C., the synthetic gas pressure is 10-1000 Pa.

9. An application of the photothermal evaporation material integrating light absorption and thermal insulation according to claim 1, the photothermal evaporation material integrating light absorption and thermal insulation is used for seawater desalination, sewage purification, and high-temperature steam sterilize.

10. A solar photothermal seawater desalination device, wherein the solar photothermal seawater desalination device comprises a light-transmissive condensation plate, an evaporation chamber, and a collection chamber in order from top to bottom; the light-transmissive condensation plate covers the evaporation chamber and guides the condensed water to the collection chamber; the photothermal evaporation material is placed in the evaporation chamber, the photothermal evaporation material integrating light absorption and heat insulation according to claim 1.

11. The solar photothermal seawater desalination device according to claim 10, wherein the solar photothermal seawater desalination device further comprises an extraction channel and a steam guiding conduit, one end of the extraction channel is connected to the evaporation chamber, the other end is connected to the collection chamber through the steam guiding conduit; the suction channel and the steam guiding conduit are provided on the side wall of the evaporation chamber.

12. The solar photothermal seawater desalination device according to claim 10, wherein the inclination angle of the light-transmissive condensation plate is 10°-60°.

13. A high-temperature steam sterilization device, wherein the high-temperature steam sterilization device comprises a steam chamber, an optical concentrator covering the steam chamber, a loading tray and a water storage cup installed inside the steam chamber, and a photothermal evaporation material in the water storage cup; the photothermal evaporation material is the photothermal evaporation material integrating light absorption and thermal insulation according to claim 1.

14. The high-temperature steam sterilization device according to claim 13, wherein the loading tray has a plurality of through holes in the vertical direction; the optical concentrator focuses the light beam into the water storage cup; the cross-sectional shape of the optical concentrator and the water storage cup are the same, and the cross-sectional area ratio is 10-100:1, and the optical concentrator and the water storage cup are assembled concentrically.

15. The high-temperature steam sterilization device according to claim 13, wherein the steam chamber is provided with a pallet for mounting the loading tray.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] FIG. 1 is a schematic structural view of a photothermal evaporation material integrating light absorption and thermal insulation provided by the present invention;

[0083] FIG. 2 is a preparation flow chart of the photothermal evaporation material integrating light absorption and thermal insulation provided by the present invention;

[0084] FIG. 3 is an optical diagram and wettability characterization results of the photothermal evaporation material integrating light absorption and thermal insulation provided in Example 1;

[0085] FIG. 4 is a scanning electron micrograph of the photothermal evaporation material integrating light absorption and thermal insulation provided in Example 1;

[0086] FIG. 5 is a light absorption curve of the photothermal evaporation material integrating light absorption and thermal insulation provided in Example 1;

[0087] FIG. 6 is an X-ray photoelectron C1s energy spectrum of the photothermal evaporation material integrating light absorption and thermal insulation provided in Example 1;

[0088] FIG. 7 is a photo-heat evaporation application effect diagram of the light-absorbing and heat-insulation integrated photo-heat evaporation material provided in Example 1;

[0089] FIG. 8 is a schematic structural view of a solar photothermal seawater desalination device provided in Examples 11-20;

[0090] FIG. 9 is a schematic diagram of an exploded structure of a solar photothermal seawater desalination device provided in Examples 11-20;

[0091] FIG. 10 is a schematic cross-sectional structural diagram of a solar photothermal seawater desalination device provided in Examples 11-20;

[0092] FIG. 11 is a schematic diagram of the principle of photothermal evaporation of the solar photothermal seawater desalination device provided in Example 11-20 and the high-temperature steam sterilization device provided in Example 21-30;

[0093] FIG. 12 is a schematic structural diagram of a high-temperature steam sterilization device provided in Examples 21-30;

[0094] FIG. 13 is a schematic diagram of the decomposition structure of the high-temperature steam sterilization device provided in Examples 21-30;

[0095] FIG. 14 is a schematic cross-sectional structural diagram of a high-temperature steam sterilization device provided in Examples 21-30;

[0096] FIG. 15 is the steam temperature during the sterilization process of the high-temperature steam sterilization device provided in Example 21.

DESCRIPTION OF THE EMBODIMENTS

[0097] In order to make the present invention more understandable, the technical solution of the present invention will be further described below with reference to the drawings and specific embodiments. The embodiments described below are only for explaining the present invention, and are not intended to limit the present invention in any form or in substance.

[0098] As shown in FIG. 1, the photothermal evaporation material integrating light absorption and thermal insulation provided by the present invention comprises a heat insulator 2 and a light absorber 1 covering the external surface of the heat insulator 2. The light absorber 1 was vertically-oriented graphene whose surface is modified with hydrophilic functional groups. The heat insulator 2 was graphene foam, and the vertically-oriented graphene and graphene foam were connected by covalent bonds. The light absorber was vertically-oriented graphene whose surface was modified with hydrophilic functional groups.

[0099] The light absorber 1 captured solar energy and converted solar energy into thermal energy to generate a local high temperature. The heat insulator 2 blocked heat transport and reduced heat dissipation. At the same time, the light absorber 1 also served as a liquid flow channel 3, sucking the liquid 4 through capillary action, so that the liquid 4 reached the local high-temperature area, and realized rapid light and heat evaporation. At the same time, the liquid flow channel 3 can protect the heat insulator 2 from being wetted by the liquid 4 and prevent the heat flow loss caused by the infiltrated liquid 4.

[0100] As shown in FIG. 2, the preparation process of the photothermal evaporation material integrating light absorption and thermal insulation provided by the present invention, that is, the vertically-oriented graphene/graphene foam comprises: the growth of the light absorber 1 and the synthesis of the heat insulator 2. First, the graphene foam with three-dimensional structure (i.e., heat insulator 2) was synthesized by hydrothermal method and freeze-drying method; then, by plasma-enhanced chemical vapor deposition technology, the external surface of the above graphene foam was covered with vertically-oriented graphite. During the preparation process, the vertically-oriented graphene was connected to the graphene foam by covalent bonds.

[0101] The photothermal evaporation material integrating light absorption and thermal insulation provided by the present invention is subjected to the following performance tests:

[0102] 1. Water contact angle: a contact angle meter, whose model is DropMeter A-200, was used to measure the water contact angle of the photothermal evaporation material integrating light absorption and thermal insulation, to characterize the hydrophilicity of the material. Using an electric pump to drop 10 L of water on the surface of the material, a high-speed camera was used to record the changing process of water droplets, and the water contact angle was calculated by the Yang-Laplace equation.

[0103] 2. Absorbance of light absorber: a UV-Visible spectrophotometer, whose model is UV-3150 UV-VIS, was used to measure the light transmittance and light reflectance of the photothermal evaporation material integrating light absorption and thermal insulation in the 200˜2600 nm band. The Formula: light absorptance=1−light transmittance−light reflectance, was used to calculate the average light absorptance.

[0104] 3. Thermal conductivity of the heat insulator: a laser thermal conductivity measuring instrument, whose model is LFA 467, was used to test the thermal conductivity of the photothermal evaporation material integrating light absorption and thermal insulation.

[0105] 4. Types of surface functional groups: an X-ray photoelectron spectrometer, whose model is VG Escalab Mark II, was used to test the X-ray energy spectrum distribution and analyze the types of functional groups.

Example 1

[0106] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 4 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 1 mmol L.sup.−1, and the concentration of ethylenediamine was 4 mmol L.sup.−1.

[0107] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 90° C. for 6 hours, then maintained at 120° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0108] 3. Soaking the obtained graphene hydrogel with ethanol aqueous solution for 6 hours, in which the volume fraction of ethanol was 10%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel.

[0109] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 6 hours, and then transferring to a drying chamber with a temperature of 0° C. and an air pressure of <650 Pa, and vacuum drying for 6 hours to obtain a graphene foam.

[0110] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 800° C.

[0111] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 5 ml min.sup.−1, the flow ratio of CH.sub.4 was 5 ml min.sup.−1, and the air pressure was adjusted to 100 Pa.

[0112] 7. Turning on the inductively coupled plasma source, adjusting the power to 250 W, and maintaining for 120 min.

[0113] 8. Turning off the plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the Ar gas valve to pass Ar as a cooling gas with a flow ratio of 10 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0114] 9. The obtained vertically-oriented graphene/graphene foam composite was exposed to an environment with an ozone concentration of 200 ppm for 3 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups include—OH, —CHO, —COGH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0115] The optical diagram of the obtained photothermal evaporation material integrating light absorption and thermal insulation was shown as a in FIG. 3, and the external surface was black.

[0116] The wettability of the vertically-oriented graphene/graphene foam modified with oxygen-containing functional groups on the surface was shown as b-d in FIG. 3, the outer vertically-oriented graphene 1 exhibited strong hydrophilicity, and the water contact angle was 26.0°, indicating the light absorber serves as a water flow channel, which can guide the transmission of water through capillary action; the internal of the graphene foam 2 exhibited strong hydrophobicity, and the water contact angle was 130.5°, indicating that the heat insulator repels the infiltration of water, and the surface water flow channel can protect the heat insulator from being wetted by water.

[0117] The microstructure of graphene foam was shown as a in FIG. 4, which showed a porous structure and low thermal conductivity, with thermal conductivity of 0.041 W m.sup.−1 K.sup.−1. The vertically-oriented graphene was composed of a carbon nanowall array, such as shown in b of FIG. 4, the vertically-oriented graphene was evenly distributed on the skeleton of the graphene foam; the vertically aligned carbon nanowall array can prevent the escape of incident light and has extremely strong light trapping ability.

[0118] As shown in FIG. 5, the average light absorptance of the obtained photothermal evaporation material integrating light absorption and thermal insulation in the wavelength band of 200-2600 nanometers was as high as 97.8%. In application, the photothermal evaporation material integrating light absorption and thermal insulation floated on the water surface, the light absorber captured solar energy, and converted the solar energy into thermal energy, generating local high temperature; the heat insulator blocked heat transfer and reduced heat dissipation; the heat insulator sucked the liquid through capillary action, so that the liquid reached the local high-temperature area, and realized rapid photothermal evaporation.

[0119] As shown in FIG. 6, the surface-modified oxygen-containing functional groups of the obtained photothermal evaporation material integrating light absorption and thermal insulation included —OH, —CHO, and —COGH.

[0120] As shown in FIG. 7, under the condition of light intensity of 10 kW m.sup.−2, only 34 seconds, saturated water vapor>100° C. could be detected in the local high-temperature area of the material, while the water temperature was almost unchanged, And the steam generation rate of this material was as high as 12.3 kg m.sup.−2 h.sup.−1, and the corresponding photothermal conversion efficiency exceeded 90%.

Example 2

[0121] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 5 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 2 mmol L.sup.−1, and the concentration of ethylenediamine was 8 mmol L.sup.−1.

[0122] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 120° C. for 12 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0123] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 12 hours, in which the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel.

[0124] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −60° C., freezing for 12 hours, and then transferring it to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam.

[0125] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 700° C.

[0126] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 5 ml min.sup.−1, the flow ratio of CH.sub.4 was 5 ml min.sup.−1, and the air pressure was adjusted to 10 Pa.

[0127] 7. Turning on the inductively coupled plasma source and the power to 250 W for 60 minutes.

[0128] 8. Turning off the plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the Ar gas valve to pass Ar as a cooling gas with a flow ratio of 10 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0129] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 4 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; where ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0130] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 3

[0131] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 5 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 3 mmol L.sup.−1, and the concentration of ethylenediamine was 12 mmol L.sup.−1.

[0132] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 90° C. for 6 hours, then maintained at 180° C. for 6 hours, and finally, cooled to room temperature to obtain a graphene hydrogel.

[0133] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 18 hours, wherein the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel.

[0134] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −40° C., freezing for 18 hours, and then transferring it to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 24 hours to a obtain graphene foam.

[0135] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 650° C.

[0136] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the gas mixture of CH.sub.4 and H.sub.2, the flow ratio of H.sub.2 was 40 ml min.sup.−1, the flow ratio of CH.sub.4 was 10 ml min.sup.−1, and the air pressure was adjusted to 300 Pa.

[0137] 7. Turning on the microwave plasma source and adjust the power to 500 W for 10 min.

[0138] 8. Turn off the plasma source, close the CH.sub.4 and H.sub.2 gas valves, opening the N.sub.2 gas valve to pass N.sub.2 as a cooling gas with a flow ratio of 50 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0139] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 2 minutes. and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0140] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 4

[0141] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 6 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 5 mmol L.sup.−1, and the concentration of ethylenediamine was 20 mmol L.sup.−1.

[0142] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high-temperature high-pressure reactor, maintained at 90° C. for 12 hours, then maintained at 180° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0143] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 24 hours, in which the volume fraction of ethanol was 30%, the purpose was to clean the remaining additives on the surface of the graphene hydrogel.

[0144] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −10° C., freezing for 24 hours, and then transfer it to a drying chamber at a temperature of −20° C. and an air pressure of <650 Pa, and vacuum drying for 48 hours to obtain a graphene foam.

[0145] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 600° C.

[0146] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 50 ml min.sup.−1, the flow ratio of CH.sub.4 was 10 ml min.sup.−1, and the air pressure was adjusted to 500 Pa.

[0147] 7. Turning on the microwave plasma source and adjusting the power to 500 W for 20 minutes.

[0148] 8. Turning off the plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the N.sub.2 gas valve to pass N.sub.2 as the cooling gas, the flow ratio was 100 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0149] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 2 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas. A photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0150] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 5

[0151] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 1 g L.sup.−1.

[0152] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 120° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0153] 3. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −10° C., freezing for 12 hours, and then transferring to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam.

[0154] 4. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 500° C.

[0155] 5. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 20 ml min.sup.−1, the flow ratio of CH.sub.4 was 1 ml min.sup.−1, and the air pressure was adjusted to 10 Pa.

[0156] 6. Turning on the inductively coupled plasma source and adjusting the power to 200 W for 180 min.

[0157] 7. Turning off the plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the Ar gas valve to pass Ar flow as a cooling gas with a flow ratio of 10 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0158] 8. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 10 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas. A photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0159] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 6

[0160] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 10 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 10 mmol L.sup.−1, and the concentration of ethylenediamine was 100 mmol L.sup.−1.

[0161] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 120° C. for 12 hours, then maintained at 180° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0162] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 24 hours, in which the volume fraction of ethanol was 30%, the purpose was to clean the remaining additives on the surface of the graphene hydrogel.

[0163] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 12 hours, and then transferring to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam.

[0164] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 1000° C.;

[0165] 6. Opening the CH.sub.4 gas valve to pass CH.sub.4, the flow ratio of CH.sub.4 was 1 ml min.sup.−1 and the air pressure was adjusted to 1000 Pa.

[0166] 7. Turning on the microwave plasma source and adjusting the power to 500 W for 1 min.

[0167] 8. Turning off the plasma source, closing the CH.sub.4 gas valve, opening the N.sub.2 gas valve to pass N.sub.2 as a cooling gas with a flow ratio of 50 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0168] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 1 min, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0169] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 7

[0170] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 6 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 1 mmol L.sup.−1, and the concentration of butanediamine was 4 mmol L.sup.−1;

[0171] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 90° C. for 6 hours, then maintained at 120° C. for 6 hours, and finally cooled to room temperature to obtain a graphene hydrogel;

[0172] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 12 hours, in which the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel;

[0173] 4. Transferring the cleaned graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 12 hours, and then transfer to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum dry for 12 hours to obtain graphene foam;

[0174] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuate to <10 Pa, and then heating to 800° C.;

[0175] 6. Opening the CH.sub.4 and H.sub.2 gas valves, and letting the gas mixture of CH.sub.4 and H.sub.2 flow. The flow ratio of H.sub.2 was 50 ml min-1, the flow ratio of CH.sub.4 was 50 ml min.sup.−1, and the air pressure was adjusted to 1000 Pa;

[0176] 7. Turning on the DC glow discharge plasma source and adjusting the power to 500 W for 30 minutes;

[0177] 8. Turning off the plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the N.sub.2 gas valve, pass N.sub.2, as the cooling gas, the flow ratio was 50 ml min.sup.−1, to be cooled to room temperature, taking out the vertically-oriented graphene/graphene foam;

[0178] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 5 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups included —OH, —CHO, —COOH; where ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0179] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 8

[0180] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 6 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 2 mmol L.sup.−1, and the concentration of butanediamine was 4 mmol L.sup.−1.

[0181] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 120° C. for 12 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0182] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 12 hours, in which the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel.

[0183] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 12 hours, and then transferring to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam.

[0184] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 700° C.

[0185] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 5 ml min.sup.−1, the flow ratio of CH.sub.4 was 5 ml min.sup.−1, and the air pressure was adjusted to 100 Pa.

[0186] 7. Turning on the microwave plasma source, adjusting the power to 250 W, and maintaining for 1 min.

[0187] 8. Turning off the microwave plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the Ar gas valve to pass Ar as a cooling gas with a flow ratio of 20 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam.

[0188] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 3 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups include—OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0189] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 9

[0190] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 6 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 3 mmol L.sup.−1; the concentration of hexamethylenediamine was 4 mmol L.sup.−1.

[0191] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 90° C. for 6 hours, then maintained at 180° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel;

[0192] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 12 hours, in which the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel;

[0193] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 12 hours, and then transferring to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam;

[0194] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 700° C.;

[0195] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 5 ml min.sup.−1, the flow ratio of CH.sub.4 was 5 ml min.sup.−1, and the air pressure was adjusted to 100 Pa;

[0196] 7. Turning on the inductively coupled plasma source, adjusting the power to 250 W, and maintaining for 60 minutes;

[0197] 8. Turning off the microwave plasma source, closing the CH.sub.4 and H.sub.2 gas valves, opening the Ar gas valve to pass Ar flow as a cooling gas with a flow ratio of 20 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam;

[0198] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 3 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups include—OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0199] The performance test results of the obtained photothermal evaporation material integrating light absorption and thermal insulation were shown in Table 1.

Example 10

[0200] 1. An aqueous solution of graphene oxide was provided, wherein the concentration of graphene oxide was 6 g L.sup.−1, the concentration of sodium tetraborate decahydrate was 4 mmol L.sup.−1, and the concentration of cyclohexanediamine was 4 mmol L.sup.−1.

[0201] 2. The prepared aqueous solution of graphene oxide was transferred to a Teflon high temperature and high-pressure reactor, maintained at 120° C. for 6 hours, then maintained at 180° C. for 6 hours, and then cooled to room temperature to obtain a graphene hydrogel.

[0202] 3. Soaking the obtained graphene hydrogel with an ethanol aqueous solution for 12 hours, in which the volume fraction of ethanol was 20%, the purpose was to clean the additives remaining on the surface of the graphene hydrogel.

[0203] 4. Transferring the washed graphene hydrogel to a freezing chamber with a temperature of −80° C., freezing for 12 hours, and then transferring to a drying chamber at a temperature of −10° C. and an air pressure of <650 Pa, and vacuum drying for 12 hours to obtain a graphene foam.

[0204] 5. Placing the obtained graphene foam in the plasma-enhanced chemical vapor deposition reaction chamber, evacuating to <10 Pa, and then heating to 700° C.

[0205] 6. Opening the CH.sub.4 and H.sub.2 gas valves to pass the mixture of CH.sub.4 and H.sub.2 flow, the flow ratio of H.sub.2 was 5 ml min.sup.−1, the flow ratio of CH.sub.4 was 5 ml min.sup.−1, and the air pressure was adjusted to 100 Pa.

[0206] 7. Turning on the inductively coupled plasma source, adjusting the power to 250 W, and maintaining for 30 minutes.

[0207] 8. Turning off the microwave plasma source, closing the CH.sub.4 and H.sub.2 gas valves, open the Ar gas valve to pass Ar flow as a cooling gas with a flow ratio of 20 ml min.sup.−1. After cooling to room temperature, removing the vertically-oriented graphene/graphene foam;

[0208] 9. The obtained vertically-oriented graphene/graphene foam was exposed to an environment with an ozone concentration of 200 ppm for 3 minutes, and the oxygen-containing functional groups were modified on the surface of the vertically-oriented graphene to construct a water flow channel. The oxygen-containing functional groups include—OH, —CHO, —COOH; specifically, ozone was generated by a dielectric barrier discharge device, and the air was used as the feeding gas; a photothermal evaporation material integrating light absorption and thermal insulation was obtained.

[0209] The performance test results of the photothermal evaporation material integrating light absorption and thermal insulation prepared in Examples 1-10 were shown in Table 1.

TABLE-US-00001 TABLE 1 Performance test results of the photothermal evaporation material integrating light absorption and thermal insulation prepared in Examples 1-10 Thermal Water Water conductivity contact angle contact angle Absorbance of the heat photothermal of the light of the heat of light insulator W conversion Examples absorber ° insulator ° absorber % m.sup.−1 K.sup.−1 efficiency Example 1 26.0 130.5 97.8% 0.041 91.6% Example 2 18.2 120.7 97.0% 0.038 91.1% Example 3 20.5 129.0 98.2% 0.033 92.0% Example 4 22.4 133.4 97.0% 0.031 91.0% Example 5 0 101.2 94.9% 0.180 86.6% Example 6 33.2 134.5 90.0% 0.051 85.0% Example 7 10.1 114.5 94.6% 0.060 86.1% Example 8 25.2 131.4 97.4% 0.041 89.0% Example 9 24.5 129.7 94.4% 0.037 87.1% Example 10 22.5 127.8 93.0% 0.029 85.3%

Examples 11-20

[0210] As shown in FIG. 8, FIG. 9 and FIG. 10, the solar photothermal seawater desalination device provided in Examples 11-20 comprises: a light-transmissive condensation plate 1, a photothermal evaporation material 2, an evaporation chamber 3, a collection chamber 4, and a water inlet 5 of the collection chamber 4, a water inlet 6 of the collection chamber 4, a water outlet 7 of the evaporation chamber, a water outlet 8 of the collection chamber, a steam guiding conduit 9, an extraction fan 10, an extraction channel 11, and a solar panel 12.

[0211] The extraction fan 10 was installed in the extraction channel 11 on the side wall of the evaporation chamber 3, and was driven by the electric energy provided by the solar panel 12 for continuous operation. The evaporation chamber 3 and the collection chamber 4 were distributed up and down to form an integrated structure. Seawater was injected into the evaporation chamber 3 through the water inlet 5 of the evaporation chamber. The photothermal evaporation material 2 was put into the evaporation chamber 3 from above and floated on the seawater. The upper surface height of the photothermal evaporation material 2 was always lower than the minimum height of the inlet of the extraction channel 11 to prevent seawater from flowing to the collection chamber 4 through the extraction channel 11 and the steam guiding conduit 9. The light-transmissive condensation plate 1 covers the evaporation chamber 3 at an inclination angle of 30°, which not only serves to close the evaporation chamber 3 but also condense the water vapor and guide the condensate water to the collection chamber 4. The photothermal evaporation material 2 absorbed solar energy and converts the solar energy into thermal energy to evaporate seawater. The extraction fan 10 drew the steam in the evaporation chamber 3 into the extraction channel 11, and guided the steam to the collection chamber 4 through the steam guiding conduit 9. During the operation of the device, the water inlet 5 and water outlet 7 of the evaporation chamber and the water inlet 6 and water outlet 8 of the collection chamber remained closed. After the device stopped working, the fresh water obtained can be transferred and used through the water outlet 8 of the collection chamber.

[0212] As shown in FIG. 11, the photothermal evaporation material 2 comprises a heat insulator 22 and a light absorber 21 covering the external surface of the heat insulator 22. The light absorber 21 was vertically-oriented graphene whose surface was modified with hydrophilic functional groups. The heat insulator 22 was a graphene foam, and the vertically-oriented graphene and graphene foam were connected in the form of covalent bonds; the light absorber 21 was vertically-oriented graphene whose surface was modified with hydrophilic functional groups.

[0213] The light absorber 21 captured solar energy and converted solar energy into thermal energy to generate a local high temperature; the heat insulator 22 blocked heat transport and reduced heat dissipation. At the same time, the light absorber 21 also served as a liquid flow channel 23 to transport liquid 24 to a local high-temperature area through capillary action, so as to achieve rapid photothermal evaporation. At the same time, the liquid flow channel 23 can protect the heat insulator 22 from being wetted by the liquid 24 and prevent the heat flow loss caused by the infiltrated liquid 24.

[0214] The photothermal evaporation materials 2 in Examples 11-20 were the photothermal evaporation material integrating light absorption and thermal insulation prepared in Examples 1-10, respectively.

[0215] Using the solar photothermal seawater desalination device provided in Example 11-20, the natural seawater with a salinity of 3.25% was subjected to evaporative condensation treatment, and the salinity of the obtained condensate water was 0.01%, which met the drinking water requirements; the natural seawater with a salinity of 9.85% was subjected to evaporative condensation treatment, and the salinity of the obtained condensate water was 0.01%, which meets the drinking water requirements; the natural seawater with a salinity of 16.7% was subjected to evaporative condensation treatment, and the salinity of the obtained condensate water was 0.02%, which meets drinking water requirements.

[0216] The performance test results of the solar photothermal seawater desalination device provided in Examples 11-20 were shown in Table 2.

TABLE-US-00002 TABLE 2 Performance test results of the solar photothermal seawater desalination device provided in Examples 11-20 Thermal Salinity after desalination Water Water conductivity Salinity Salinity Salinity contact angle contact angle Absorbance of the heat Photothermal before before before of the light of the heat of light insulator W conversion desalination desalination desalination Examples absorber ° insulator ° absorber % m.sup.−1K.sup.−1 efficiency 3.25% 9.85% 16.7% Example11 26.0 130.5 97.8% 0.041 .sup. 91% 0.01% 0.01% 0.02% Example12 18.2 120.7 97.0% 0.038 90.1% 0.01% 0.02% 0.02% Example13 20.5 129.0 98.2% 0.033 91.4% 0.01% 0.01% 0.02% Example14 22.4 133.4 97.0% 0.031 90.5% 0.01% 0.01% 0.02% Example15 0 101.2 94.9% 0.180 83.7% 0.02% 0.02% 0.02% Example16 33.2 134.5 90.0% 0.051 84.4% 0.01% 0.01% 0.01% Example17 10.1 114.5 94.6% 0.060 85.3% 0.01% 0.02% 0.02% Example18 25.2 131.4 97.4% 0.041 88.4% 0.01% 0.02% 0.02% Example19 24.5 129.7 94.4% 0.037 86.4% 0.01% 0.02% 0.02% Example20 22.5 127.8 93.0% 0.029 85.0% 0.01% 0.02% 0.02%

Examples 21-30

[0217] As shown in FIG. 12, FIG. 13 and FIG. 14, the high-temperature steam sterilization device provided in Examples 21-30 comprises: a clamp 1, a fixing ring 2, a sealing ring 3, an optical concentrator 4, a photothermal evaporation material 5, a storage water cup 6, a loading tray 7, a steam chamber 8.

[0218] As shown in FIG. 11, the photothermal evaporation material 2 comprises a heat insulator 22 and a light absorber 21 covering the external surface of the heat insulator 22. The light absorber 21 was vertically-oriented graphene whose surface was modified with hydrophilic functional groups. The heat insulator 22 was graphene foam, and the vertically-oriented graphene and graphene foam were connected in the form of covalent bonds; the light absorber 21 was vertically-oriented graphene whose surface was modified with hydrophilic functional groups.

[0219] The light absorber 21 captured solar energy and converted solar energy into thermal energy to generate a local high temperature. The heat insulator 22 blocked heat transport and reduced heat dissipation. At the same time, the light absorber 21 also served as a liquid flow channel 23 to transport liquid 24 to a local high-temperature area through capillary action, so as to achieve rapid photothermal evaporation. At the same time, the liquid flow channel 23 can protect the heat insulator 22 from being wetted by the liquid 24 and prevent the heat flow loss caused by the infiltrated liquid 24.

[0220] As shown in FIG. 12, FIG. 13 and FIG. 14, the loading tray 7 was placed on the pallet of the evaporation chamber 8; the water storage cup 6 was placed in the groove in the center of the loading tray 7; a certain amount of water was added to the water storage cup 6, and the photothermal evaporation material 2 was put into the water storage cup 6 from above, the photothermal evaporation material 2 floated on the surface of the water; the items to be sterilized was placed on the loading tray 7 in the evaporation chamber 8; then the optical concentrator 4 was covered on the evaporation chamber 8, and the evaporation chamber 8 was closed with a sealing ring 3, a fixing ring 2 and a clamp 1.

[0221] The photothermal evaporation materials 2 in Examples 21-30 were the photothermal evaporation material integrating light absorption and thermal insulation prepared in Examples 1-10, respectively.

[0222] Using the high-temperature steam sterilization device provided in Example 21, operating under natural light, the light intensity was 1.0-1.2 kW m.sup.−2, using a standard biological indicator as a test of sterilization effect, when the indicator color changes from purple to yellow, it indicated that the sterilization has failed. When the color of the indicator remains purple, it indicated that the sterilization has succeeded. As shown in FIG. 15, after 11 minutes of operation, the temperature in the evaporation chamber reaches 121° C., which was the expected sterilization temperature. According to the WHO standard, maintaining a high-temperature steam environment of 121° C. for 30 minutes can achieve sufficient disinfection and destruction. Therefore, after 41 minutes of operation, the work was stopped. The biological indicator after sterilization was transferred to 56° C. environment and incubated for 48 h. After observation, the indicator without sterilization was yellow, and the indicator after sterilization was purple, indicating successful sterilization.

[0223] The performance test results of the high-temperature steam sterilization device provided in Examples 21-30 were shown in Table 3.

TABLE-US-00003 TABLE 3 Performance test results of the high-temperature steam sterilization device provided in Examples 21-30 Thermal Water Water conductivity contact angle contact angle Absorbance of the heat of the light of the heat of light insulator W Sterilization Sterilization Examples absorber ° insulator ° absorber % m.sup.−1 K.sup.−1 time min effect Example21 26.0 130.5 97.8% 0.041 41 Success Example22 18.2 120.7 97.0% 0.038 48 Success Example23 20.5 129.0 98.2% 0.033 43 Success Example24 22.4 133.4 97.0% 0.031 50 Success Example25 0 101.2 94.9% 0.180 70 Success Example26 33.2 134.5 90.0% 0.051 74 Success Example27 10.1 114.5 94.6% 0.060 60 Success Example28 25.2 131.4 97.4% 0.041 57 Success Example29 24.5 129.7 94.4% 0.037 62 Success Example30 22.5 127.8 93.0% 0.029 65 Success

[0224] The above is a detailed description of the present invention in combination with examples, but the implementation of the present invention is not limited by the above examples. Any other changes, replacements, and combination simplifications made under the core guiding idea of the patent of the present invention are included in this Within the scope of protection of invention patents.