CN107235591B

CN107235591B - Application of photo-thermal conversion copper sulfide composite film in water treatment

Info

Publication number: CN107235591B
Application number: CN201710505149.9A
Authority: CN
Inventors: 王振洋; 张淑东; 张忠平; 赵婷婷; 李年
Original assignee: Hefei Institutes of Physical Science of CAS
Current assignee: Hefei Institutes of Physical Science of CAS
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2020-07-24
Anticipated expiration: 2037-06-28
Also published as: CN107235591A

Abstract

The invention discloses an application of a photothermal conversion copper sulfide composite film in water treatment, which is used for seawater desalination or sewage treatment; the photo-thermal conversion copper sulfide composite film is formed by growing defect type copper sulfide nano particles capable of carrying out solar photo-thermal conversion on the surface of a black spongy porous polyethylene film. The composite film is a device prepared by combining an independent hydrophilic film and a photothermal conversion material, has porous surface, high hydrophilicity, can float on the surface of a water body, is cooperated with the solar photothermal conversion performance of copper sulfide nanoparticles on the surface of the film, can be applied to the evaporation process of natural water, greatly improves the efficiency of solar water evaporation, can be widely applied to sewage treatment, seawater desalination, water body circulation and the like, and is favorable for realizing the effective utilization of energy and the protection of the environment.

Description

Application of photo-thermal conversion copper sulfide composite film in water treatment

Technical Field

The invention relates to an application of a photo-thermal conversion film, belonging to the field of water treatment.

Background

With the continuous progress of science and technology in the new era, energy and environmental problems have become one of the prominent problems facing all over the world, and especially the shortage of water resources has attracted more and more attention from human beings.

The total water storage capacity stored in the earth is about 1386 × 10 billion cubic meters, wherein the ocean water accounts for 96.5 percent, the fresh water resource only accounts for 3.5 percent, the fresh water mainly exists in the forms of glaciers and deep groundwater, and the fresh water directly available for human beings such as rivers and lakes accounts for 0.3 percent of the total fresh water in the world, so that water shortage is the first problem facing cities all over the world.

With the development of economy and the growth of population, particularly today of high-speed development of economy in China, various kinds of sewage are generated while benefits are created. In order to realize sustainable development and solve the problem of water resource shortage, the resource recycling of sewage becomes the key for realizing the aim. Sewage treatment has been widely applied in various fields such as construction, agriculture, traffic, energy, petrochemical industry, environmental protection, urban landscape, medical treatment, catering and the like. Most of the existing sewage treatment technologies utilize a biodegradation method, and the quality of the sewage effluent treated by the method has certain limitations, high cost and high energy consumption.

Solar energy is radiation energy without any chemical substance, so that the solar energy is an inexhaustible energy treasury which is most reliable and environment-friendly, and is also the most abundant renewable energy in China. The seawater desalination and sewage treatment realized by solar energy through the water evaporation system can effectively solve the problem of energy consumption, which is also an effective way for solar energy collection and utilization in modern science and technology. However, much research in this direction is focused on optimizing the device system and adding equipment to increase the evaporation efficiency, which is accompanied by higher energy loss and equipment maintenance costs. Therefore, the exploration of the simple and efficient solar water evaporation method has great research value.

Disclosure of Invention

In order to avoid the defects of the prior art, the invention provides the application of the photothermal conversion copper sulfide composite film in water treatment, and aims to solve the technical problems of improving the photothermal performance of a common polyethylene film to expand the application of the common polyethylene film in water treatment and improving the efficiency of solar water evaporation.

In order to realize the purpose of the invention, the following technical scheme is adopted:

the invention discloses an application of a photothermal conversion copper sulfide composite film in water treatment, which is characterized in that: the composite film is used for seawater desalination or sewage treatment, and particularly floats on seawater to be desalinated or sewage to be treated, then is irradiated by a light source, and converts light energy into heat energy to promote seawater or sewage evaporation and collect evaporated water, so that treatment is realized.

The photothermal conversion copper sulfide composite film is formed by growing defect type copper sulfide nano-particles Cu capable of carrying out solar photothermal conversion on the surface of a black spongy porous polyethylene film_2-xS，0≦x≦1。

The light source can be sunlight, simulated sunlight or halogen lamps.

The photothermal conversion copper sulfide composite film is prepared by the following method:

a. pretreatment of porous polyethylene film

Firstly, spraying a layer of copper simple substance on the surface of a porous polyethylene film by magnetron sputtering, wherein the mass of the sprayed copper simple substance accounts for 1-5% of the mass of the porous polyethylene film, and obtaining a PE-Cu film;

then putting the PE-Cu film into water at the temperature of room temperature to 50 ℃ for cleaning, taking out the PE-Cu film, sequentially cleaning the PE-Cu film by absolute ethyl alcohol and ultrapure water, and drying the PE-Cu film for 10 to 12 hours at the temperature of 30 to 45 ℃ for later use;

b. conversion of elemental copper on PE-Cu film

0.0369g to 0.1107g of sulfur source and 0.4781g to 1.4343g of polyvinylpyrrolidone are weighed, added into 35m L to 150m L of ethylene glycol, ultrasonically treated until the mixture is dissolved, and then transferred into a hydrothermal reaction kettle, wherein the sulfur source is thiourea, sodium thiosulfate or thioacetamide.

Putting 0.0306 g-0.0612 g of PE-Cu film into the hydrothermal reaction kettle, and completely unfolding the film and immersing the film in the solution; then transferring the hydrothermal reaction kettle to an oven with the temperature of 150-180 ℃, and reacting for 10-12 hours to convert the copper simple substance into Cu_2- _xS；

And naturally cooling after the reaction is finished, taking out the film, sequentially cleaning the film by using absolute ethyl alcohol and ultrapure water, and finally drying the film at the temperature of between 30 and 45 ℃ for 10 to 12 so as to obtain the photothermal conversion copper sulfide composite film.

The composite film is a device prepared by combining an independent hydrophilic film and a photothermal conversion material, has porous surface, high hydrophilicity, can float on the surface of a water body, is cooperated with the solar photothermal conversion performance of copper sulfide nanoparticles on the surface of the film, can be applied to the evaporation process of natural water, greatly improves the efficiency of solar water evaporation, can be widely applied to sewage treatment, seawater desalination, water body circulation and the like, and is favorable for realizing the effective utilization of energy and the protection of the environment. Experiments prove that the film is simulated and applied to the evaporation process of water in nature, the high photo-thermal evaporation efficiency of pure water and artificial seawater at a water-air interface under the irradiation of sunlight is realized (the evaporation efficiency of water vapor when solar energy directly irradiates the surface of a water body is 23%, and the evaporation efficiency of the water vapor of the water body covered with the photo-thermal conversion copper sulfide composite film can be improved to 52%), and the problem of low evaporation efficiency of water under natural conditions is effectively solved.

Compared with the prior art, the invention has the beneficial effects that:

1. halas et al reported in ACS Nano, gold nanoparticles are dispersed in an aqueous solution, surface plasmon resonance of the gold nanoparticles is used for generating heat to generate steam bubbles inside a water body, and the bubbles need to escape from the inside to the surface of water-air and then release steam, so that the efficiency of water evaporation is greatly limited. Compared with the traditional method for heating the water body by using the nano particle solution, the photothermal conversion copper sulfide composite film can float on the surface of the water body, thereby reducing the heat loss caused by heat transfer and the like and improving the photothermal evaporation efficiency.

2. Compared with the direct water evaporation by solar energy, the photo-thermal conversion copper sulfide composite film covers the water surface, the infrared thermal effect of copper sulfide nano particles on the film on the solar energy is utilized to raise the water body temperature, and steam escapes through the pores on the film, so that the efficiency of solar energy water evaporation is greatly improved, and the film has potential application values in the aspects of seawater purification, sewage treatment, water body circulation and the like.

3. In various devices for water vapor evaporation, the composite film has cheap and easily-obtained raw materials, and copper sulfide has low price and can be recycled while realizing photothermal conversion, while the report of Yanming L iu and the like in advanced materials shows that gold nano-film is used for photothermal conversion, the raw materials are expensive, dust-free cloth is required to float on the surface of a water body to serve as the support of the gold nano-film, and the structure is complex.

Drawings

FIG. 1 shows PE-Cu obtained in example 1_2-xThe optical photograph (A) and scanning Electron micrograph (B) of the S film revealed that PE-Cu was present_2-xThe S film can keep good integrity and has porous surface.

FIG. 2 shows SEM scanning electron micrograph (A) and EDS energy spectrum analysis (B) of PE-Cu thin film obtained in example 1, and PE-Cu film obtained_2-xSEM scanning electron micrograph (C) and EDS energy spectrum analysis result (D) of the S thin film, and PE-Cu thin film are inserted into the upper right corners of the SEM scanning electron micrographs of FIGS. 2(A) and (C)_2-xA photo of the S film was compared with that of PE-Cu_2-xThe surface of the S film is generated by copper sulfide nano particles.

FIG. 3 shows PE-Cu obtained in example 1_2-xX-ray diffraction patterns (XRD) of the S film and the PE-Cu film.

FIG. 4 shows PE-Cu obtained in example 1_2-xVisible-ultraviolet-near infrared absorption spectra of the S film, the PE-Cu film, the black spongy porous PE film and the common transparent PE film can be obtained from the figure, and the PE-Cu film_2-xThe S film has good absorption at visible-ultraviolet-near infrared wavelengths.

FIG. 5 shows the results obtained in example 1PE-Cu_2-xComparison of the surface contact angle (B) of the S thin film with the surface contact angle (A) of the PE-Cu thin film revealed that PE-Cu was present_2-xThe contact angle of the S film is reduced, and the hydrophilicity is enhanced.

FIG. 6 shows PE-Cu obtained in example 1_2-xTime-temperature spectrograms of the S film, the PE-Cu film and the common transparent PE film under illumination.

FIG. 7 is a view showing that pure water is directly irradiated under a halogen lamp and the surface is covered with PE-Cu in example 2_2-xThe pure water of the S film has the change quantity of the quality along with the irradiation time under the irradiation of the halogen lamp.

Detailed Description

The technical solution of the present invention is further described below with reference to specific examples.

Example 1

In this example, a photothermal conversion copper sulfide composite film was prepared and its photothermal conversion efficiency was verified as follows:

a. pretreatment of porous polyethylene film

Firstly, spraying a layer of copper simple substance on the surface of a black spongy porous polyethylene film with the thickness of about 153 micrometers by magnetron sputtering to obtain a PE-Cu film; the mass of the sprayed copper element accounts for 1.46 percent of the mass of the porous polyethylene film.

Then the PE-Cu film is put into hot water at 50 ℃ for cleaning, taken out and then sequentially cleaned by absolute ethyl alcohol and ultrapure water for a plurality of times, and dried for 12 hours at 30 ℃ for standby.

b. Conversion of elemental copper on PE-Cu film

Weighing 0.0369g of thiourea (Tu) and 0.4781g of polyvinylpyrrolidone (PVP), adding into 35m L ethylene glycol, ultrasonically dissolving for 20min, and transferring into a 50m L hydrothermal reaction kettle;

putting 0.0306g of PE-Cu film into a hydrothermal reaction kettle, and completely unfolding the PE-Cu film and immersing the PE-Cu film in a solution; then transferring the hydrothermal reaction kettle to a 180 ℃ oven for reaction for 12 hours to convert the copper simple substance into Cu_2-xS；

Naturally cooling after the reaction is finished, taking out the film, sequentially cleaning the film for a plurality of times by absolute ethyl alcohol and ultrapure water, and finally drying the film for 12 hours at 30 ℃ to obtain the photo-thermalConversion copper sulfide composite film (noted as PE-Cu)_2-xS film).

FIG. 1 shows PE-Cu obtained in this example_2-xThe optical photograph (A) and scanning Electron micrograph (B) of the S film revealed that PE-Cu was present_2-xThe S film can keep good integrity, has porous surface and is suitable for manufacturing thin film devices.

FIG. 2 shows SEM scanning electron micrograph (A) and EDS energy spectrum analysis (B) of the PE-Cu thin film obtained in the present example, and PE-Cu_2-xSEM scanning electron micrograph (C) and EDS energy spectrum analysis result (D) of the S thin film, and comparison shows that PE-Cu_2-xCopper sulfide nanoparticles are generated on the surface of the S film, and an EDS energy spectrum proves that sulfur is introduced into the surface of the polyethylene-copper sulfide film.

FIG. 3 shows PE-Cu obtained in this example_2-xX-ray diffraction (XRD) spectra of the S film and the PE-Cu film, and PE-Cu film is compared with PE-Cu film_2-xNewly forming copper sulfide nano crystals on the S film, wherein an XRD spectrogram of the copper sulfide nano crystals corresponds to a CuS standard card: JCPDS Card NO. 06-0464.

FIG. 4 shows the PE-Cu obtained in this example_2-xVisible-ultraviolet-near infrared absorption spectra of the S film, the PE-Cu film, the black spongy porous PE film and the common transparent polyethylene plastic film (corresponding to the common PE film in the figure). From the spectrogram, PE-Cu_2-xThe S film has good absorption at visible-ultraviolet-near infrared wavelength, the light absorption performance of the S film is superior to that of a PE-Cu film, a black spongy porous PE film and a common transparent polyethylene plastic film, and the S film can be used for photo-thermal conversion of solar energy.

FIG. 5 shows PE-Cu prepared in this example_2-xComparison of the surface contact angle (B) of the S film with the surface contact angle (A) of the PE-Cu film. As can be seen, the original PE-Cu film was hydrophobic with a surface contact angle of 117.97 degrees, whereas the PE-Cu film prepared in this example_2-xThe contact angle of S is 26.81 degrees, and the hydrophilicity is enhanced.

FIG. 6 shows PE-Cu obtained in this example_2-xTime-temperature spectra of the S film, the PE-Cu film and the common transparent polyethylene plastic film (corresponding to the common PE film in the figure). The film is irradiated under a halogen lampAnd recording the surface temperature of the film by using a thermal infrared imager. As can be seen from the figure, the PE-Cu obtained in this example_2-xThe S film can reach 52.2 ℃ under the irradiation condition, the surface temperature of the PE-Cu film can reach 42.3 ℃, and the surface temperature of the common transparent PE film can only reach 33.1 ℃, so that the PE-Cu film obtained in the embodiment is proved to be_2-xThe S film has good photo-thermal conversion performance.

Example 2

This example uses the PE-Cu obtained in example 1_2-xS, carrying out a water treatment simulation experiment on the film, which comprises the following steps:

a. taking a circular PE-Cu sheet with the diameter of 4 cm_2-xAnd (S) cleaning the film with absolute ethyl alcohol and ultrapure water for several times, and drying the film for 12 hours at the temperature of 30 ℃ for later use.

b. A cylindrical beaker with a diameter of 4 cm was filled with ultrapure water and placed on an electronic balance. The device is placed under the irradiation of a halogen lamp with 275W of energy, the surface of ultrapure water is 17 cm away from the halogen lamp, and a light source is vertically irradiated on the surface of the water body. The irradiation time was 14 minutes while recording the mass change of the device due to the evaporation of ultrapure water during the irradiation.

c. Filling ultrapure water in a cylindrical beaker with the diameter of 4 cm, placing the beaker on an electronic balance, and putting the PE-Cu obtained in the step a_2-xThe S film covers the water surface. The device is placed under the irradiation of a halogen lamp with 275W energy, the surface of ultrapure water is 17 cm away from the halogen lamp, and a light source is vertically irradiated on PE-Cu_2-xS film and water surface. The irradiation time was 14 minutes while recording the mass change of the device due to the evaporation of ultrapure water during the irradiation.

As can be seen from fig. 7, when pure water was irradiated directly under the halogen lamp, water vapor was not generated until about 630 seconds after the start of irradiation, and the quality of pure water was reduced. After 14 minutes of irradiation, the mass of pure water was reduced by 0.29g and the evaporation rate was 0.99kgm^-2h^-1. And the surface is covered with PE-Cu_2-xWhen the pure water of the S film is irradiated with the halogen lamp, water vapor starts to be generated in about 160 seconds after the start of the irradiation, and the quality of the pure water is reduced. After 14 minutes of irradiation, the mass of pure water was reduced by 1.18g and evaporatedThe speed was 4.03kg m^-2h^-1Greater than that of the uncoated PE-Cu_2-xThe water vapor evaporation rate of pure water in the case of S film under the irradiation of halogen lamp shows that PE-Cu_2-xThe S film can generate a photo-thermal effect under the irradiation of a halogen lamp light source, so that the temperature of the water surface is increased, and the water evaporation rate is increased.

Example 3

This example changed the light source of example 2 to a power density of about 1000W m^-2The same water treatment simulation experiment was performed with an irradiation time of 30 minutes.

The results show that after 30 minutes of irradiation, no PE-Cu coating was applied_2-xThe pure water mass of the S film was reduced by 0.23g, and the evaporation rate was 0.366kg m^-2h^-1. And the surface is covered with PE-Cu_2-xAfter the pure water of the S film is irradiated for 30 minutes under the simulated sunlight, the mass of the pure water is reduced by 0.52g, and the evaporation rate is 0.828kg m^-2h^-1Description of PE-Cu_2-xThe S film can generate a photo-thermal effect under the irradiation of simulated sunlight, so that the temperature of the water surface is raised, and the efficiency of water evaporation is improved.

The conversion efficiency of solar energy into heat required for water evaporation is calculated from the formula η Qe/Qs, where Qs is the solar power density (1000W m)^-2) Qe is calculated from the formula Qe ═ He (dm/dt) ═ He × v, where He is the heat of evaporation of water (≈ 2260kJ kg)^-1) M is the amount of water evaporated, t is the time, v is the water evaporation rate. Calculated by the data, the water vapor evaporation efficiency of the simulated sunlight directly irradiates the surface of the water body is 23 percent, and the simulated sunlight is covered by PE-Cu_2-xThe water vapor evaporation efficiency of the water body of the S film is 52 percent, which is improved by 2.3 times.

Example 4

This example changed the light source of example 2 to a power density of about 1000W m^-2The same water treatment simulation experiment is carried out by changing the used water body into artificial seawater, and the irradiation time is 30 minutes.

The results show that after 30 minutes of irradiation, no PE-Cu coating was applied_2-xArtificial seawater of S filmHas a mass reduction of 0.26g and an evaporation rate of 0.414kg m^-2h^-1. And the surface is covered with PE-Cu_2-xAfter the artificial seawater of the S film is irradiated for 30 minutes under simulated sunlight, the mass is reduced by 0.6g, and the evaporation rate is 0.955kg m^-2h^-1. Description of PE-Cu_2-xThe S film can generate a photo-thermal effect under the irradiation of simulated sunlight, so that the surface temperature of the artificial seawater is raised, and the water evaporation efficiency of the artificial seawater is improved.

From the above, the photothermal conversion copper sulfide composite film can be used in the fields of sewage treatment, seawater purification and the like, and has great potential.

The present invention is not limited to the above exemplary embodiments, and any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The application of the photothermal conversion copper sulfide composite film in water treatment is characterized in that: used for seawater desalination or sewage treatment;

the photothermal conversion copper sulfide composite film is formed by growing defect type copper sulfide nano-particles Cu capable of carrying out solar photothermal conversion on the surface of a black spongy porous polyethylene film_2-xS, 0 ≦ x ≦ 1; the photothermal conversion copper sulfide composite film is prepared by the following method:

a. pretreatment of porous polyethylene film

b. conversion of elemental copper on PE-Cu film

Weighing 0.0369 g-0.1107 g of sulfur source and 0.4781 g-1.4343 g of polyvinylpyrrolidone, adding the sulfur source and the polyvinylpyrrolidone into 35m L-150 m L of ethylene glycol, performing ultrasonic treatment until the sulfur source and the polyvinylpyrrolidone are dissolved, and transferring the mixture into a hydrothermal reaction kettle, wherein the sulfur source is thiourea, sodium thiosulfate or thioacetamide;

putting 0.0306 g-0.0612 g of PE-Cu film into the hydrothermal reaction kettle, and completely unfolding the film and immersing the film in the solution; then transferring the hydrothermal reaction kettle to an oven with the temperature of 150-180 ℃, and reacting for 10-12 hours to convert the copper simple substance into Cu_2-xS；

2. The use of the photothermal conversion copper sulfide composite film according to claim 1 in water treatment, wherein: the method comprises the steps of floating the photothermal conversion copper sulfide composite film on seawater to be desalinated or sewage to be treated, irradiating the film by a light source, converting light energy into heat energy by the photothermal conversion copper sulfide composite film, promoting the seawater or the sewage to evaporate, and collecting evaporated water to realize treatment.

3. The use of the photothermal conversion copper sulfide composite film according to claim 2 in water treatment, wherein: the light source is sunlight, simulated sunlight or a halogen lamp.