Preparation method and application of photo-thermal-photocatalytic solar interface evaporator

Abstract

The invention is applicable to the technical field of sunlight utilization and wastewater treatment, and provides a preparation method and application of a photo-thermal-photocatalytic solar interface evaporator. According to the method, alkalized polyacrylonitrile aerogel is used as a matrix framework, BiOI-Bi-Bi2O3 composite particles are used as main photo-thermal-photocatalytic functional materials, and the photo-thermal-photocatalytic solar interface evaporator is prepared. And the single layer of Ti < 3 > C < 2 > T < x > MXene is used as a synergistic photo-thermal and photo-photocatalytic auxiliary agent. According to the prepared composite aerogel, BiOI, Bi2O3 and Bi are combined to form a stable interface heterostructure, and meanwhile, full-wave-band efficient utilization of a solar spectrum is realized by utilizing single-layer Ti < 3 > C < 2 > T < x > MXene. The evaporator can be used for effectively treating a water source containing complex pollutants and synchronously realizing desalination and deep purification. The evaporator has remarkable effects in the aspects of improving the photo-thermal conversion efficiency, optimizing the evaporation process and the resource utilization rate, protecting the environment, saving energy and the like, and has wide application prospects in the aspects of water resource shortage and water environment pollution.

Description

Technical Field

[0001] This invention belongs to the field of solar energy utilization and wastewater treatment technology, and particularly relates to a method for preparing and applying a photothermal-photocatalytic solar interface evaporator. Background Technology

[0002] With the increasing scarcity of global freshwater resources and the intensifying impact of climate change on water resources, interfacial water evaporation technology (SIET), driven by renewable solar energy, is gradually becoming an important approach to producing clean water due to its environmental friendliness and sustainability. This technology mainly relies on solar-powered interfacial evaporators. These evaporators have high hydrophilicity and photothermal conversion capabilities, converting sunlight incident on the water surface into heat and confining this heat to the water layer at the interface. This allows the water molecules in this layer to absorb sufficient heat and evaporate as water vapor, thus yielding clean freshwater resources.

[0003] However, this technology also has certain limitations. Because the wastewater contains volatile organic pollutants (VOCs), VOCs are easily evaporated along with water molecules during the interfacial evaporation process and accumulate in the distilled water, making it impossible to meet the standards for water discharge or recycling.

[0004] Photocatalytic degradation of organic pollutants is a low-cost and sustainable water pollution treatment technology. Utilizing natural solar energy to couple photocatalysis with photothermal effects can effectively prevent secondary pollution of the aquatic environment caused by water treatment materials and VOCs in the water. Bismuth-based compounds, with their strong designability and suitable band structure, can be widely used in the photothermal-photocatalytic field. Since photocatalysis and photothermal effects respond to different wavelengths of the solar spectrum (e.g., ultraviolet 300-400nm, visible 400-780nm, and visible-near-infrared 780-2500nm), single functional materials only have a specific absorption range for the solar spectrum. In reality, complex preparation processes are often required to add three or more functional materials synergistically to achieve efficient utilization of the full spectrum (300-2500nm) of sunlight by the solar evaporator. This is detrimental to the performance stability of solar thermal evaporators during large-scale applications. Therefore, developing a bismuth-based, high-efficiency photothermal-photocatalytic solar interfacial evaporator that utilizes the full spectrum of solar energy, with a high removal rate of VOCs in water, while maintaining good adaptability, durability, and sustainable and stable operation in complex aquatic environments (high salinity, organic dyes, antibiotics, heavy metals, etc.), is an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and applying a photothermal-photocatalytic solar interface evaporator, aiming to solve the problems mentioned in the background art.

[0006] The present invention is implemented as follows: a method for preparing a photothermal-photocatalytic solar interface evaporator includes the following steps:

[0007] Step 1: Dissolve potassium iodide as an iodine salt and bismuth nitrate separately in an organic solvent to obtain solution A and solution B; mix solution A and solution B and place them in a reaction vessel, react for a period of time using a solvothermal synthesis method, then centrifuge, wash and dry the precipitate to obtain BiOI-Bi composite nanoparticles;

[0008] Step 2: Dissolve polyacrylonitrile powder and BiOI-Bi composite nanoparticles in N,N-dimethylformamide solution to prepare a uniform dark green spinning solution, and obtain polyacrylonitrile / BiOI-Bi fiber membrane by electrospinning technology.

[0009] Step 3: Add a certain amount of polyacrylonitrile / BiOI-Bi fiber membrane to deionized water for homogenization treatment to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; add sodium hydroxide to ethanol / water solution, heat to boiling in an oil bath, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for a period of time to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion;

[0010] Step 4: Mix lithium fluoride and hydrochloric acid and stir. Then slowly add Ti3AlC2 to the lithium fluoride / hydrochloric acid mixed solution to react and prepare multilayer Ti3C2T. x MXene; Washing multilayer Ti3C2T with deionized water x After MXene was neutralized, it was sonicated, centrifuged to obtain the supernatant, and then freeze-dried to obtain a monolayer of Ti3C2T. x MXene, a single-layer Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion;

[0011] Step 5: Mix the polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with monolayer Ti3C2T x The MXene dispersion was blended and freeze-dried to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

[0012] In a further technical solution, in step 1, the molar mass ratio of bismuth nitrate to potassium iodide is 1:1 to 1:1.5; the organic solvent is ethylene glycol, and the volume ratio of ethylene glycol in solution A to solution B is 2:1; the reaction time in the solvothermal synthesis method is 12 to 18 hours, and the reaction temperature is 160 to 180°C.

[0013] In a further technical solution, in step 2, the mass ratio of polyacrylonitrile to BiOI-Bi nanoparticles is 1:1 to 1.2:1; the electrospinning technical parameters are: voltage 12 to 14 kV, pushing speed 0.5 to 1.5 mL / h, distance 10 to 15 cm, and time 6 to 10 h.

[0014] In a further technical solution, in step 3, the mass fraction of the polyacrylonitrile / BiOI-Bi fiber dispersion is 1.0-2.0 wt%; the volume ratio of ethanol / water solution is 1:3.5; the mass of sodium hydroxide added is 1-1.5 g; the reaction temperature is 80-90℃; and the reaction time is 30 min.

[0015] In a further technical solution, in step 4, the mass of Ti3AlC2 is 1-2g; the mass of lithium fluoride is 1.6-3.2g; the concentration of hydrochloric acid is 9mol / L, and the volume is 20-40mL; the reaction temperature is 35-40℃, and the reaction time is 24-48h; the ultrasonic time is 1-3h; the pre-freezing time in the freeze-drying method is 10-24h, and the pre-freezing temperature is -20 to -18℃; the freeze-drying time is 24-48h, and the freeze-drying temperature is -100 to -90℃.

[0016] A further technical solution is that, in step 5, a single layer of Ti3C2T... x The concentration of MXene dispersion is 10–20 mg / mL; polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion and monolayer Ti3C2T x The mass ratio of MXene dispersion is 2:1; the pre-freezing time in the freeze-drying method is 10 to 24 hours, and the pre-freezing temperature is -20 to -18℃; the freeze-drying time is 24 to 48 hours, and the freeze-drying temperature is -100 to -90℃.

[0017] Another objective of this invention is to provide an application of a photothermal-photocatalytic solar interface evaporator. Based on the photothermal-photocatalytic solar interface evaporator prepared by the above method, it is applied to wastewater treatment. This photothermal-photocatalytic solar interface evaporator has a full-spectrum solar energy response range, thereby achieving efficient water environment purification through solar interface evaporation.

[0018] This invention provides a method for preparing and applying a photothermal-photocatalytic solar interfacial evaporator. The method involves using alkalized polyacrylonitrile aerogel as the matrix framework, BiOI-Bi-Bi2O3 composite particles as the main functional material for photothermal-photocatalysis, and a single-layer Ti3C2T... xMXene was used as a synergistic photothermal-photocatalytic promoter. A composite aerogel was prepared by combining low-energy-absorption BiOI, high-energy-absorption Bi2O3, and full-spectrum-responsive Bi to form a stable interfacial heterostructure. Simultaneously, a monolayer Ti3C2T with broad-spectrum absorption and conversion was utilized. x MXene achieves efficient utilization of the entire solar spectrum. This evaporator can effectively treat water sources containing complex pollutants (such as salinity and other pollutants mentioned above), simultaneously achieving desalination and deep purification. The evaporator demonstrates significant effects in improving photothermal conversion efficiency, optimizing the evaporation process and resource utilization, and promoting environmental protection and energy conservation. It has broad application prospects in addressing water scarcity and water pollution. Attached Figure Description

[0019] Figure 1 Macroscopic and microscopic morphology images of the aerogel provided in Example 3 (where a is a macroscopic image; b is a microscopic morphology image);

[0020] Figure 2 XRD patterns of the aerogels provided in Examples 1-3;

[0021] Figure 3 The X-ray photoelectron spectrum of the aerogel provided in Example 3 (where a, b, c, d, and e are schematic diagrams of the full spectrum scan, C 1s, O 1s, Bi 4f, and Ti 2p spectra, respectively).

[0022] Figure 4 Surface contact angle test of the aerogel provided in Example 3;

[0023] Figure 5 Absorption spectra of the aerogels provided in Examples 1-3;

[0024] Figure 6 The photocatalytic degradation curves and pseudo-first-order photocatalytic kinetic curves of Congo red dye provided by the aerogel in Examples 1-3 are shown (where a is the photocatalytic degradation curve of Congo red dye provided by the aerogel in Examples 1-3; b is the pseudo-first-order photocatalytic kinetic curve of Congo red dye provided by the aerogel in Examples 1-3).

[0025] Figure 7 The graphs show the test results of the evaporation amount, evaporation rate, and photothermal conversion efficiency of the aerogel provided in Example 3 for pure water (where a is the evaporation amount test result graph; b is the evaporation rate and photothermal conversion efficiency test result graph).

[0026] Figure 8 The graph shows the photothermal evaporation cycle test of the aerogel on pure water provided in Example 3;

[0027] Figure 9The graphs show the test results of the evaporation amount and evaporation rate of the aerogel provided in Example 3 on the brine (where a is the evaporation amount test result graph; b is the evaporation rate test result graph).

[0028] Figure 10 The surface state of the aerogel provided in Example 3 after evaporation in a 10 wt% sodium chloride solution for 1 hour;

[0029] Figure 11 The aerogel provided in Example 3 was used to test the ion concentration in the evaporation water of simulated seawater;

[0030] Figure 12 The graphs show the test results of the evaporation amount and evaporation rate of the aerogel provided in Example 3 for non-volatile pollutant wastewater (where a is the evaporation amount test result graph; b is the evaporation rate test result graph).

[0031] Figure 13 The aerogel provided in Example 3 shows the changes in phenol content and absorbance of distilled water after phenol wastewater evaporation (where a is the phenol content in distilled water; b is the change in absorbance of distilled water). Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0034] An embodiment of the present invention provides a method for preparing a photothermal-photocatalytic solar interface evaporator, comprising the following steps:

[0035] Step 1: Dissolve potassium iodide as an iodine salt and bismuth nitrate separately in an organic solvent to obtain solution A and solution B; mix solution A and solution B and place them in a reaction vessel, react for a period of time using a solvothermal synthesis method, then centrifuge, wash and dry the precipitate to obtain BiOI-Bi composite nanoparticles;

[0036] Step 2: Dissolve polyacrylonitrile powder and BiOI-Bi composite nanoparticles in N,N-dimethylformamide solution to prepare a uniform dark green spinning solution, and obtain polyacrylonitrile / BiOI-Bi fiber membrane by electrospinning technology.

[0037] Step 3: Add a certain amount of polyacrylonitrile / BiOI-Bi fiber membrane to deionized water for homogenization treatment to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; add sodium hydroxide to ethanol / water solution, heat to boiling in an oil bath, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for a period of time to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion;

[0038] Step 4: Mix lithium fluoride and hydrochloric acid and stir. Then slowly add Ti3AlC2 to the lithium fluoride / hydrochloric acid mixed solution to react and prepare multilayer Ti3C2T. x MXene; Washing multilayer Ti3C2T with deionized water x After MXene was neutralized, it was sonicated, centrifuged to obtain the supernatant, and then freeze-dried to obtain a monolayer of Ti3C2T. x MXene, a single-layer Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion;

[0039] Step 5: Mix the polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with monolayer Ti3C2T x The MXene dispersion was blended and freeze-dried to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

[0040] In a preferred embodiment of the present invention, in step 1, the molar mass ratio of bismuth nitrate to potassium iodide is 1:1 to 1:1.5; the organic solvent is ethylene glycol, and the volume ratio of ethylene glycol in solution A to solution B is 2:1; the reaction time in the solvothermal synthesis method is 12 to 18 hours, and the reaction temperature is 160 to 180°C.

[0041] In a preferred embodiment of the present invention, in step 2, the mass ratio of polyacrylonitrile to BiOI-Bi nanoparticles is 1:1 to 1.2:1; the electrospinning technical parameters are: voltage 12 to 14 kV, pushing speed 0.5 to 1.5 mL / h, distance 10 to 15 cm, and time 6 to 10 h.

[0042] In a preferred embodiment of the present invention, in step 3, the mass fraction of the polyacrylonitrile / BiOI-Bi fiber dispersion is 1.0-2.0 wt%; the volume ratio of ethanol / water solution is 1:3.5; the mass of sodium hydroxide added is 1-1.5 g; the reaction temperature is 80-90 °C; and the reaction time is 30 min.

[0043] In a preferred embodiment of the present invention, in step 4, the mass of Ti3AlC2 is 1-2 g; the mass of lithium fluoride is 1.6-3.2 g; the concentration of hydrochloric acid is 9 mol / L and the volume is 20-40 mL; the reaction temperature is 35-40 °C and the reaction time is 24-48 h; the ultrasonic time is 1-3 h; the pre-freezing time in the freeze-drying method is 10-24 h and the pre-freezing temperature is -20 to -18 °C; the freeze-drying time is 24-48 h and the freeze-drying temperature is -100 to -90 °C.

[0044] In a preferred embodiment of the present invention, in step 5, a single layer of Ti3C2T x The concentration of MXene dispersion is 10–20 mg / mL; polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion and monolayer Ti3C2T x The mass ratio of MXene dispersion is 2:1; the pre-freezing time in the freeze-drying method is 10 to 24 hours, and the pre-freezing temperature is -20 to -18℃; the freeze-drying time is 24 to 48 hours, and the freeze-drying temperature is -100 to -90℃.

[0045] An embodiment of the present invention provides an application of a photothermal-photocatalytic solar interface evaporator. Based on the photothermal-photocatalytic solar interface evaporator prepared by the above method, it is applied to wastewater treatment. The photothermal-photocatalytic solar interface evaporator has a full spectrum response range of solar energy, thereby achieving efficient water environment purification through solar interface evaporation.

[0046] Several specific embodiments are provided below to verify the effectiveness of this method.

[0047] Example 1: This example provides a method for preparing an aerogel-type solar interface evaporator, specifically including the following steps:

[0048] Step 1: Dissolve 1.2g of polyacrylonitrile powder in 10mL of N,N-dimethylformamide solution to prepare a uniform colorless and transparent spinning solution; electrospin the spinning solution under the conditions of spinning distance 15cm, voltage 13kV, feed speed 1.0mL / h, and electrospinning time 10h, and use aluminum foil as the membrane receiving substrate to obtain polyacrylonitrile fiber membrane.

[0049] Step 2: Add 1.83g of polyacrylonitrile fiber membrane to 100mL of deionized water for homogenization to obtain polyacrylonitrile fiber dispersion; then add 1.5g of sodium hydroxide to ethanol / water solution (1:3.5v / v), heat to boiling in an oil bath at 85℃, add polyacrylonitrile fiber dispersion, and react for 30min to obtain alkalized polyacrylonitrile fiber dispersion.

[0050] Step 3: Pre-freeze 100mg of alkalized polyacrylonitrile fiber dispersion at -20℃ for 24h, and then freeze-dry it at -100℃ for 48h in a freeze dryer to obtain alkalized polyacrylonitrile aerogel.

[0051] Example 2: This example provides a method for preparing an aerogel-type photocatalytic solar interfacial evaporator, specifically including the following steps:

[0052] Step 1: Dissolve 0.4980g potassium iodide and 1.4552g bismuth nitrate in 12.5mL and 25mL of ethylene glycol, respectively, to obtain solution A and solution B, and stir each for 30min. After thoroughly mixing solution A and solution B, place them in a reaction vessel and react at 160℃ for 12h. After solvothermal synthesis, centrifuge, wash and dry the precipitate to obtain BiOI-Bi nanoparticles.

[0053] Step 2: Dissolve 1.2g of polyacrylonitrile powder and 1g of BiOI-Bi nanoparticles in 10mL of N,N-dimethylformamide solution to prepare a uniform dark green spinning solution; electrospin the spinning solution under the conditions of spinning distance 15cm, voltage 13kV, feed speed 1.0mL / h, and electrospinning time 10h, and use aluminum foil as the membrane receiving substrate to obtain polyacrylonitrile / BiOI-Bi fiber membrane.

[0054] Step 3: Add 1.83g of polyacrylonitrile / BiOI-Bi fiber membrane to 100mL of deionized water for homogenization to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; then add 1.5g of sodium hydroxide to ethanol / water solution (1:3.5v / v), heat to boiling in an oil bath at 85℃, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for 30min to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion.

[0055] Step 4: Pre-freeze 100 mg of polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion at -20℃ for 24 h, and then freeze-dry it at -100℃ for 48 h in a freeze dryer to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 aerogel.

[0056] Example 3: This example provides a method for preparing a composite aerogel-type photothermal-photocatalytic solar interface evaporator, specifically including the following steps:

[0057] Step 1: Dissolve 0.4980g potassium iodide and 1.4552g bismuth nitrate in 12.5mL and 25mL of ethylene glycol, respectively, to obtain solution A and solution B, and stir each for 30min. After thoroughly mixing solution A and solution B, place them in a reaction vessel and react at 160℃ for 12h. After solvothermal synthesis, centrifuge, wash and dry the precipitate to obtain BiOI-Bi nanoparticles.

[0058] Step 2: Dissolve 1.2g of polyacrylonitrile powder and 1g of BiOI-Bi nanoparticles in 10mL of N,N-dimethylformamide solution to prepare a uniform dark green spinning solution; electrospin the spinning solution under the conditions of spinning distance 15cm, voltage 13kV, feed speed 1.0mL / h, and electrospinning time 10h, and use aluminum foil as the membrane receiving substrate to obtain polyacrylonitrile / BiOI-Bi fiber membrane.

[0059] Step 3: Add 1.83g of polyacrylonitrile / BiOI-Bi fiber membrane to 100mL of deionized water for homogenization to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; then add 1.5g of sodium hydroxide to ethanol / water solution (1:3.5v / v), heat to boiling in an oil bath at 85℃, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for 30min to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion.

[0060] Step 4: Dissolve 3.2g of lithium fluoride in 40mL of 9M hydrochloric acid and stir continuously for 10min; then, gradually add 2g of Ti3AlC2 powder to the mixture and react at 40℃ for 48h; wash the resulting black suspension by centrifugation until neutral; sonicate the washed product for 3h, centrifuge again to collect the black supernatant, pre-freeze at -20℃ for 24h, and then freeze-dry at -100℃ for 48h to obtain Ti3C2T x MXene monolayer powder; monolayer Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion;

[0061] Step 5: Mix 100 mg of polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with 10 mL of 10 mg / mL monolayer Ti3C2T x The MXene dispersion was blended and pre-frozen at -20°C for 24 hours, and then freeze-dried at -100°C for 48 hours in a freeze dryer to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

[0062] The density of the prepared polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel was 0.0583 ± 0.001 g / cm³. -3 The internal pore size is 3.417±0.002nm; in the surface contact angle test, the complete wetting time of the material surface is 0.12s.

[0063] like Figure 1 As shown, the monolayer sheet-like Ti3C2T in the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel prepared in Example 3 x MXene structures and BiOI-Bi-Bi2O3 composite particles are distributed on the porous structure of the alkalized polyacrylonitrile matrix; such as Figure 2 As shown, in the X-ray diffraction pattern of polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene, a peak at 16.5° belonging to the polyacrylonitrile matrix and characteristic peaks belonging to BiOI and Bi can be observed. Furthermore, due to alkali treatment, the BiOI and Bi portions in BiOI-Bi are converted to Bi2O3, forming BiOI-Bi-Bi2O3. Therefore, the diffraction peak corresponding to Bi2O3 (PDF#73-2062) also appears in the diffraction pattern. A characteristic peak appears at 60°, corresponding to Ti3C2T. x The (110) crystal plane of MXene proves that Ti3C2T x The successful incorporation of MXene; such as Figure 3 As shown, X-ray photoelectron spectroscopy confirms the presence of C, N, O, Ti, and Bi elements on the surface of the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel; Figure 4 As shown, this demonstrates that the surface of the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel exhibits good hydrophilicity; for example... Figure 5 As shown, this demonstrates the interaction between the photocatalyst BiOI-Bi-Bi2O3 and the photothermal material Ti3C2T. x The combination of MXene enables highly efficient light capture of over 94% across the entire spectrum.

[0064] Example 4: This example provides a method for preparing a composite aerogel-type photothermal-photocatalytic solar interface evaporator, specifically including the following steps:

[0065] Step 1: Dissolve 0.4980g potassium iodide and 1.4552g bismuth nitrate in 12.5mL and 25mL of ethylene glycol, respectively, to obtain solution A and solution B, and stir each for 30min. After thoroughly mixing solution A and solution B, place them in a reaction vessel and react at 160℃ for 12h. After solvothermal synthesis, centrifuge, wash and dry the precipitate to obtain BiOI-Bi nanoparticles.

[0066] Step 2: Dissolve 1.1g of polyacrylonitrile powder and 0.5g of BiOI-Bi nanoparticles in 10mL of N,N-dimethylformamide solution to prepare a uniform dark green spinning solution; electrospin the spinning solution under the conditions of spinning distance 15cm, voltage 13kV, feed speed 1.0mL / h, and electrospinning time 10h, and use aluminum foil as the membrane receiving substrate to obtain polyacrylonitrile / BiOI-Bi fiber membrane.

[0067] Step 3: Add 1.33g of polyacrylonitrile / BiOI-Bi fiber membrane to 100mL of deionized water for homogenization to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; then add 1.5g of sodium hydroxide to ethanol / water solution (1:3.5v / v), heat to boiling in an oil bath at 85℃, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for 15min to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion.

[0068] Step 4: Dissolve 3.2g of lithium fluoride in 40mL of 9M hydrochloric acid and stir continuously for 10min; then, gradually add 2g of Ti3AlC2 powder to the mixture and react at 40℃ for 48h; wash the resulting black suspension by centrifugation until neutral; sonicate the washed product for 3h, centrifuge again to collect the black supernatant, pre-freeze at -20℃ for 24h, and then freeze-dry at -100℃ for 48h to obtain Ti3C2T x MXene monolayer powder; monolayer Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion;

[0069] Step 5: Mix 100 mg of polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with 10 mL of 10 mg / mL monolayer Ti3C2T x The MXene dispersion was blended and pre-frozen at -20°C for 24 hours, and then freeze-dried at -100°C for 48 hours in a freeze dryer to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

[0070] The density of the prepared polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel was 0.065 ± 0.001 g / cm³. -3 The internal pore size is 3.413±0.002nm; in the surface contact angle test, the complete wetting time of the material surface is 0.15s.

[0071] Example 5: This example provides a method for preparing a composite aerogel-type photothermal-photocatalytic solar interface evaporator, specifically including the following steps:

[0072] Step 1: Dissolve 0.4980g potassium iodide and 1.4552g bismuth nitrate in 12.5mL and 25mL of ethylene glycol, respectively, to obtain solution A and solution B, and stir each for 30min. After thoroughly mixing solution A and solution B, place them in a reaction vessel and react at 160℃ for 12h. After solvothermal synthesis, centrifuge, wash and dry the precipitate to obtain BiOI-Bi nanoparticles.

[0073] Step 2: Dissolve 1.0g of polyacrylonitrile powder and 0.2g of BiOI-Bi nanoparticles in 10mL of N,N-dimethylformamide solution to prepare a uniform dark green spinning solution; electrospin the spinning solution under the conditions of spinning distance 15cm, voltage 13kV, feed speed 1.0mL / h, and electrospinning time 10h, and use aluminum foil as the membrane receiving substrate to obtain polyacrylonitrile / BiOI-Bi fiber membrane.

[0074] Step 3: Add 1g of polyacrylonitrile / BiOI-Bi fiber membrane to 100mL of deionized water for homogenization to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; then add 1.5g of sodium hydroxide to ethanol / water solution (1:3.5v / v), heat to boiling in an oil bath at 85℃, add polyacrylonitrile / BiOI-Bi fiber dispersion, and react for 10min to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion.

[0075] Step 4: Dissolve 3.2g of lithium fluoride in 40mL of 9M hydrochloric acid and stir continuously for 10min; then, gradually add 2g of Ti3AlC2 powder to the mixture and react at 40℃ for 48h; wash the resulting black suspension by centrifugation until neutral; sonicate the washed product for 3h, centrifuge again to collect the black supernatant, pre-freeze at -20℃ for 24h, and then freeze-dry at -100℃ for 48h to obtain Ti3C2T x MXene monolayer powder; monolayer Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion;

[0076] Step 5: Mix 100 mg of polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with 10 mL of 10 mg / mL monolayer Ti3C2T xThe MXene dispersion was blended and pre-frozen at -20°C for 24 hours, and then freeze-dried at -100°C for 48 hours in a freeze dryer to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

[0077] The density of the prepared polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel was 0.083 ± 0.001 g cm³. -3 The internal pore size is 3.405±0.002nm; in the surface contact angle test, the complete wetting time of the material surface is 0.13s.

[0078] Example 6: Performance test of Congo red dye removal in water by a composite aerogel photothermal-photocatalytic solar interface evaporator;

[0079] The aerogels prepared in Examples 1-5 were used to test the photocatalytic degradation of Congo red dye in wastewater. The specific procedures were as follows: The aerogel samples prepared in Examples 1-5 were placed at the surface of 60 mL of Congo red aqueous solution (5 mg / L). Before illumination, they were allowed to stand for 30 min in the dark to achieve adsorption equilibrium. A xenon lamp source (equipped with an AM1.5G filter, light intensity 1 kW m²) was turned on. -2 Every 15 minutes, 3 mL of the reaction solution was collected for sampling. The absorbance of the solution was measured using a UV-Vis spectrophotometer at the maximum absorption wavelength of Congo red (499 nm). The removal rate R% of Congo red was calculated using Lambert-Beer's law, as shown in the following formula:

[0080] R%=(1-C t / C0)×100%

[0081] Among them, C t C0 is the absorbance value of the solution after reaction t min, and C0 is the initial absorbance value of the Congo red solution.

[0082] As shown in Table 1 and Figure 6 As shown in the results, compared with the samples in Example 1 and Example 2, the samples prepared in Examples 3-5 of the present invention can achieve efficient removal of organic pollutants.

[0083] Table 1

[0084] sample R％ Alkaliized polyacrylonitrile 0.00％ <![CDATA[Polyacrylonitrile / BiOI - Bi - Bi2O3]]> 34.00％ <![CDATA[Polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene]]> 94.50％～96.80％

[0085] Example 7: Performance Test of Photothermal-Photocatalytic Solar Interfacial Evaporator for Pure Water

[0086] Photothermal pure water evaporation tests were conducted using the solar interface evaporators prepared in Examples 1-5. The specific procedures were as follows: A beaker containing pure water was placed on an analytical balance, and the aerogel samples prepared in Examples 1-5 were placed at the water surface. A xenon lamp light source (equipped with an AM1.5G filter, light intensity 1 kW m²) was turned on. -2 The mass change was recorded every 10 minutes with an accuracy of 0.0001g.

[0087] As shown in Table 2 and Figure 7 As shown in the results, the samples prepared in Examples 3-5 of this invention have good photothermal conversion and water transport capabilities.

[0088] Table 2

[0089] sample <![CDATA[Evaporation rate (kg·m -2 ·h -1 )]]> pure water 0.17 Alkaliized polyacrylonitrile 1.33 <![CDATA[Polyacrylonitrile / BiOI-Bi-Bi2O3]]> 1.50 <![CDATA[Polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene]]> 2.15～2.18

[0090] Cyclic tests were conducted on the solar-thermal pure water evaporation using the solar interface evaporator prepared in Example 3. Figure 8 As shown, the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel maintains a stable evaporation rate even after multiple cycles. The results indicate that the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in this invention possesses stable water evaporation performance and cycle durability.

[0091] Example 8: Photothermal evaporation performance test of composite aerogel-type photothermal-photocatalytic solar interface evaporator on salt water;

[0092] Photothermal brine evaporation tests were conducted using the solar interface evaporator prepared in Example 3. The specific procedures were as follows: Beakers containing sodium chloride solutions of different mass fractions (0 wt%, 3.5 wt%, 5 wt%, and 10 wt%) were placed on an analytical balance. The polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel sample prepared in Example 3 was placed at the surface of the water. A xenon lamp source (equipped with an AM1.5G filter, with a light intensity of 1 kW m²) was turned on. -2 The mass change was recorded every 10 minutes with an accuracy of 0.0001g. For example... Figure 9 As shown, in sodium chloride solutions with mass fractions of 0 wt%, 3.5 wt%, 5 wt%, and 10 wt%, the evaporation rates of the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel prepared in Example 3 were 2.18 kg m³, respectively. -2 h -1 2.11kg m -2 h -1 2.04kg m -2 h -1 and 1.82kg m -2 h -1 At the same time, such as Figure 10As shown, no salt crystals were observed on the aerogel surface after evaporation in a 10 wt% sodium chloride solution for 1 hour. The results indicate that the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in this invention exhibits good salt resistance.

[0093] Example 9: Test of photothermal evaporation performance of seawater by a composite aerogel-type photothermal-photocatalytic solar interface evaporator;

[0094] The solar interface evaporator prepared in Example 3 was used to conduct a photothermal seawater evaporation test. The specific operation was as follows: Simulated seawater (containing 25g L) was placed in a container... -1 Sodium chloride, 5g / L -1 Magnesium sulfate, 5g / L -1 Magnesium chloride, 1.5g L -1 Calcium chloride, 0.7g / L -1 Potassium chloride, 0.2 g / L -1 Sodium bicarbonate and 4g L -1 A beaker containing sodium sulfate was placed on an analytical balance. The polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel sample prepared in Example 3 was placed at the surface of simulated seawater. A xenon lamp source (equipped with an AM1.5G filter, with a light intensity of 1 kW m²) was turned on. -2 The evaporated water was collected. The ion concentration in the distilled water was quantified using inductively coupled plasma optical emission spectrometry. Figure 11 As shown, the ion concentration in distilled water is significantly lower (Na+). + 1.11 mg / L -1 ;Mg 2+ 0.04 mg / L -1 ;K + 0.33 mg / L -1 ;Ca 2+ 0.16 mg / L -1 The salt content is far below the standards set by the World Health Organization. The results show that the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in this invention has excellent salt barrier properties.

[0095] Example 10: Photothermal evaporation performance test of composite aerogel-type photothermal-photocatalytic solar interface evaporator on non-volatile pollutant wastewater;

[0096] The solar interface evaporator prepared in Example 3 was used to conduct a photothermal wastewater evaporation test. The specific operation was as follows: wastewater containing different non-volatile pollutants (100 mg / L) was used. -1 Congo red, 100mg L -1 Tetracycline hydrochloride, 100 mg / L -1A beaker containing potassium dichromate was placed on an analytical balance, and the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel sample prepared in Example 3 was placed at the liquid surface. A xenon lamp source (equipped with an AM1.5G filter, light intensity 1 kW m²) was turned on. -2 The mass change was recorded every 10 minutes with an accuracy of 0.0001 g. The absorbance curve of distilled water was determined using a UV-Vis spectrophotometer. Figure 12 As shown, the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel prepared in Example 3 was subjected to a tetracycline hydrochloride solution (2.02 kg m³). -2 h -1 ), potassium dichromate solution (1.72 kg m -2 h -1 ) and Congo red solution (2.09 kg m -2 h -1 Although the evaporation rate in the aerogel is slightly lower than that in pure water, it still exhibits a relatively high evaporation rate. The results show that the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in this invention possesses adaptability to complex environments.

[0097] Example 11: Photothermal evaporation performance test of composite aerogel-type photothermal-photocatalytic solar interface evaporator on wastewater containing volatile pollutants;

[0098] The photothermal evaporation performance of the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in Example 3 was tested for wastewater containing volatile pollutants. The specific operation was as follows: A phenol aqueous solution (10 mg / L) was prepared... -1 The beaker was placed on the analytical balance, and the aerogel sample prepared in Example 3 was placed at the liquid surface. The xenon lamp light source (equipped with an AM1.5G filter, light intensity 1 kW m²) was turned on. -2 The evaporated water was collected. The absorbance of the distilled water was measured using a UV-Vis spectrophotometer. Figure 13 As shown, the polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel prepared in Example 3 reduced the phenol concentration in distilled water from 9.59 mg / L. -1 Decreased to 0.99 mg / L -1 The results show that the composite aerogel-type photothermal-photocatalytic solar interface evaporator prepared in this invention has the ability to intercept and purify pollutants in wastewater containing volatile pollutants.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a photothermal-photocatalytic solar interface evaporator, characterized in that, Includes the following steps: Step 1: Dissolve potassium iodide as an iodine salt and bismuth nitrate separately in an organic solvent to obtain solution A and solution B; mix solution A and solution B and place them in a reaction vessel, react them using a solvothermal synthesis method, and then centrifuge, wash and dry the precipitate to obtain BiOI-Bi composite nanoparticles; Step 2: Dissolve polyacrylonitrile powder and BiOI-Bi composite nanoparticles in N,N-dimethylformamide solution to prepare a uniform dark green spinning solution, and obtain polyacrylonitrile / BiOI-Bi fiber membrane by electrospinning technology. Step 3: Add a certain amount of polyacrylonitrile / BiOI-Bi fiber membrane to deionized water for homogenization treatment to obtain polyacrylonitrile / BiOI-Bi fiber dispersion; Sodium hydroxide was added to an ethanol / water solution, and the mixture was heated to boiling in an oil bath. Then, polyacrylonitrile / BiOI-Bi fiber dispersion was added, and the reaction yielded polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion. Step 4: Mix lithium fluoride and hydrochloric acid and stir. Then slowly add Ti3AlC2 to the lithium fluoride / hydrochloric acid mixed solution to react and prepare multilayer Ti3C2T. x MXene; Washing multilayer Ti3C2T with deionized water x After MXene was neutralized, it was sonicated, centrifuged to obtain the supernatant, and then freeze-dried to obtain a monolayer of Ti3C2T. x MX ene, a single layer of Ti3C2T x Monolayer Ti3C2T was prepared by ultrasonic dispersion of MXene in deionized water. x MXene dispersion; Step 5: Mix the polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion with monolayer Ti3C2T x The MXene dispersion was blended and freeze-dried to obtain polyacrylonitrile / BiOI-Bi-Bi2O3 / MXene aerogel.

2. The method for preparing the photothermal-photocatalytic solar interface evaporator according to claim 1, characterized in that, In step 1, the molar mass ratio of bismuth nitrate to potassium iodide is 1:1 to 1:1.5; the organic solvent is ethylene glycol, and the volume ratio of ethylene glycol in solution A to solution B is 2:1; the reaction time in the solvothermal synthesis method is 12 to 18 hours, and the reaction temperature is 160 to 180°C.

3. The method for preparing the photothermal-photocatalytic solar interface evaporator according to claim 1, characterized in that, In step 2, the mass ratio of polyacrylonitrile to BiOI-Bi nanoparticles is 1:1 to 1.2:1; the electrospinning technical parameters are: voltage 12 to 14 kV, pushing speed 0.5 to 1.5 mL / h, distance 10 to 15 cm, and time 6 to 10 h.

4. The method for preparing the photothermal-photocatalytic solar interface evaporator according to claim 1, characterized in that, In step 3, the mass fraction of the polyacrylonitrile / BiOI-Bi fiber dispersion is 1.0-2.0 wt%; the volume ratio of ethanol / water solution is 1:3.5; the mass of sodium hydroxide added is 1-1.5 g; the reaction temperature is 80-90℃; and the reaction time is 30 min.

5. The method for preparing the photothermal-photocatalytic solar interface evaporator according to claim 1, characterized in that, In step 4, the mass of Ti3AlC2 is 1-2 g; the mass of lithium fluoride is 1.6-3.2 g; the concentration of hydrochloric acid is 9 mol / L and the volume is 20-40 mL; the reaction temperature is 35-40℃ and the reaction time is 24-48 h; the ultrasonic time is 1-3 h; the pre-freezing time in the freeze-drying method is 10-24 h and the pre-freezing temperature is -20 to -18℃; the freeze-drying time is 24-48 h and the freeze-drying temperature is -100 to -90℃.

6. The method for preparing the photothermal-photocatalytic solar interface evaporator according to claim 1, characterized in that, In step 5, a single layer of Ti3C2T x The concentration of MXene dispersion is 10–20 mg / mL; polyacrylonitrile / BiOI-Bi-Bi2O3 fiber dispersion and monolayer Ti3C2T x The mass ratio of MXene dispersion is 2:1; the pre-freezing time in the freeze-drying method is 10 to 24 hours, and the pre-freezing temperature is -20 to -18℃; the freeze-drying time is 24 to 48 hours, and the freeze-drying temperature is -100 to -90℃.

7. An application of a photothermal-photocatalytic solar interface evaporator, wherein the photothermal-photocatalytic solar interface evaporator prepared according to the preparation method of any one of claims 1-6 is characterized in that, It is applied to wastewater treatment.

Images