Application of nano copper oxide/carbon nitride composite material in water bloom control
阅读说明：本技术 纳米氧化铜/氮化碳复合材料在水华控制中的应用 (Application of nano copper oxide/carbon nitride composite material in water bloom control ) 是由 王震宇 曹雪松 王传洗 于 2020-06-12 设计创作，主要内容包括：本发明公开了纳米氧化铜/氮化碳复合材料在水华控制中的应用,属于水污染处理领域。本发明以氮化碳和醋酸铜为原料,加入NaOH与铜离子反应生成CuOH,CuOH附着在C<Sub>3</Sub>N<Sub>4</Sub>上,通过煅烧被转化为CuO,得到纳米氧化铜/氮化碳复合材料。本发明中的纳米氧化铜/氮化碳复合材料相较铜和氮化碳都有效提升了抑藻性能,最优铜负载比例下制备的铜负载C<Sub>3</Sub>N<Sub>4</Sub>的抑藻性能是C<Sub>3</Sub>N<Sub>4</Sub>的4.5倍；纳米氧化铜/氮化碳复合材料的性能稳定,在成分复杂的自然水体中仍具有很好的控制水华的能力。此外,本发明制备的纳米氧化铜/氮化碳复合材料可重复使用性较C<Sub>3</Sub>N<Sub>4</Sub>更好；在抑藻的同时,还能够快速去除藻毒素。(The invention discloses an application of a nano copper oxide/carbon nitride composite material in water bloom control, belonging to the field of water pollution treatment. The invention takes carbon nitride and copper acetate as raw materials, NaOH is added to react with copper ions to generate CuOH, and the CuOH is attached to C 3 N 4 And the CuO is converted into the CuO through calcination, so that the nano copper oxide/carbon nitride composite material is obtained. Compared with copper and carbon nitride, the nano copper oxide/carbon nitride composite material effectively improves the algae inhibition performance, and the copper load C prepared under the optimal copper load proportion 3 N 4 Has the algae inhibiting performance of C 3 N 4 4.5 times of; the nano copper oxide/carbon nitride composite material has stable performance and still has good capability of controlling water bloom in natural water with complex components. In addition, the nano copper oxide/carbon nitride composite material prepared by the invention has higher reusability than C 3 N 4 Better still; can inhibit algae and remove algal toxin quickly.)
1. A method for preparing a nano copper oxide/carbon nitride composite material for controlling bloom, comprising the steps of:
(1) the carbon nitride precursor is taken to be calcined,to obtain C3N4；
(2) C is to be3N4Dispersing in a copper acetate solution with the concentration of 0.05-0.50 mM, oscillating the mixture until the mixture is completely mixed, adding a NaOH solution into the mixed solution, performing ultrasonic treatment and centrifugation, and taking a precipitate for drying; and calcining, washing and freeze-drying the dried mixture to obtain the nano copper oxide/carbon nitride composite materials with different copper loading amounts.
2. The method according to claim 1, wherein the carbon nitride precursor in step (1) is any one or more of urea, melamine and thiourea.
3. The method of claim 1, wherein the calcining conditions of step (1) are: heating to 500-600 ℃ at a temperature rising speed of 1-3 ℃/min, and keeping for 2-6 h.
4. The method according to claim 1, wherein C obtained in the step (1) is calcined3N4Also subjected to purification treatment, and the purification method comprises the following steps: after the calcination is finished, cooling to room temperature, sequentially cleaning the white product with ethanol and distilled water, repeating the cleaning step for 2-3 times, and removing unreacted carbon nitride precursors; then, dispersing the white product in distilled water, carrying out ultrasonic treatment at 400-600W for 6-10 h, centrifuging at 250-5000 rpm for 10-30 min to remove large particulate matters which are not stripped, and freeze-drying the completely stripped product to obtain purified C3N4。
5. The method of claim 1, wherein Cu and C in the copper acetate in step (2)3N4The mass ratio of (A) to (B) is 0.005 to 0.05.
6. The method of claim 1, wherein the mixture is shaken for 5-15 hours in step (2) to complete mixing.
7. The nano copper oxide/carbon nitride composite material for controlling water bloom, which is prepared by the method according to any one of claims 1 to 6.
8. The use of the nano copper oxide/carbon nitride composite material of claim 7 for inhibiting algal growth and removing algal toxins.
9. The application according to claim 8, wherein the method of application is: and (3) adding the nano copper oxide/carbon nitride composite materials with different copper loading amounts into the water bloom algae suspension, and exposing for 24-96 hours.
10. The use according to claim 9, wherein the loading of Cu in the nano copper oxide/carbon nitride composite is 0.02 wt%.
Technical Field
The invention relates to an application of a nano copper oxide/carbon nitride composite material in water bloom control, belonging to the field of water pollution treatment.
Background
The water bloom refers to the phenomenon of water quality deterioration caused by the rapid growth of blue algae in a fresh water body and the release of toxic algal toxins. It can cause death of aquatic organisms, threaten human health and even destroy the water ecosystem. Therefore, efficient control of the occurrence of bloom and removal of algal toxins from water is imminent. The visible light catalysis technology gradually draws the attention of researchers in the aspect of water bloom control due to the characteristics of high efficiency, safety, sustainability and low cost.
Carbon nitride (C)3N4) The two-dimensional nano semiconductor material is a two-dimensional nano semiconductor material formed by polymerization of a scarlet structure, and has great application prospects in the fields of photocatalytic pollutant degradation, hydrogen production through hydrolysis and the like due to the characteristics of low raw material price, visible light response, stable physical and chemical properties and the like. Meanwhile, C is reported3N4Has great application space in the aspect of controlling the water bloom. However, there is a distance from practical use, mainly due to: 1.C3N4The utilization efficiency of visible light is low; 2.C3N4The recombination speed of surface electron-hole pairs is high; 3. in real water body, C3N4Susceptible to Dissolved Organic Matter (DOM) in water. Thus, optimizing C3N4The prepared C has high visible light utilization efficiency, high electron-hole separation speed and low possibility of being interfered by DOM3N4The composite material is used for efficiently controlling the occurrence of water bloom, and is worthy of further research.
Copper as a traditional algicide can inhibit the growth of water bloom algae, but has toxicity to non-target organisms (such as beneficial aquatic plants, fishes and the like), and the application of copper as the algicide is greatly limited due to large dosage and high cost.
Loading metal nanoparticles to C3N4Surface, is an effective way to improve its photocatalytic performance. Copper as a traditional algicide loaded to C3N4Surface pair C3N4What effect photocatalytic algae inhibition performance has? At present, no relevant report is found. And C supported by copper-based nano material3N4Whether or not C can be increased3N4Ability to degrade algal toxins? It is not known at present.
Disclosure of Invention
[ problem ] to
C3N4When used for controlling the water bloom, the utilization efficiency of visible light is low, C3N4The surface electron-hole pair has high recombination speed, is easily influenced by soluble organic matters (DOM) in water in real water, and the like. Copper as a traditional algicide can inhibit the growth of water bloom algae, but has toxicity to non-target organisms, and the application of copper as the algicide is greatly limited due to large dosage and high cost.
[ solution ]
Aiming at the technical problems and the application purpose, the invention provides a nano copper oxide/carbon nitride composite material, which utilizes C loaded by a copper-based nano material3N4To simultaneously control the occurrence of bloom and remove algal toxins.
The invention provides a preparation method of a nano copper oxide/carbon nitride composite material for controlling water bloom, which comprises the following steps:
(1) calcining carbon nitride precursor to obtain C3N4；
(2) C is to be3N4Dispersing in a copper acetate solution with the concentration of 0.05-0.50 mM, oscillating the mixture until the mixture is completely mixed, adding a NaOH solution into the mixed solution, and performing ultrasonic treatment, centrifugation and drying; and calcining, washing and freeze-drying the dried mixture to obtain the nano copper oxide/carbon nitride composite materials with different copper loading amounts.
In one embodiment of the present invention, the carbon nitride precursor in step (1) is any one or more of urea, melamine, and thiourea.
In one embodiment of the present invention, the calcination conditions in step (1) are: heating to 500-600 ℃ at a temperature rising speed of 1-3 ℃/min, and keeping for 2-6 h.
In one embodiment of the present invention, C is the same as that described in step (1)3N4After calcination, the calcination needs to be purified, and the purification method comprises the following steps: cooling to room temperature after calcination, sequentially washing the white product with ethanol and distilled water for 2-3 times, and removing unreacted carbon nitride precursors; then, dispersing the white product in distilled water, performing ultrasonic treatment at 400-600W for 6-10 h, centrifuging at 2500-5000 rpm for 10-30 min to remove large particulate matters which are not stripped, and freeze-drying the completely stripped product to obtain purified C3N4。
In one embodiment of the present invention, Cu and C in the copper acetate in the step (2)3N4The mass ratio of (A) to (B) is 0.005 to 0.05.
In one embodiment of the invention, in the step (2), the mixture is shaken for 5-15 h until the mixture is completely mixed.
In one embodiment of the present invention, the specific operation of the ultrasound in the step (2) is: 300-500W ultrasonic waves are carried out for 0.5-1 h.
In one embodiment of the present invention, the calcination conditions in step (2) are: heating to 500-600 ℃ at a temperature rising speed of 1-3 ℃/min, and keeping for 2-6 h.
In one embodiment of the present invention, after the yellow product is calcined in step (2), the obtained yellow product is washed with distilled water for 2 to 4 times and then freeze-dried.
In one embodiment of the present invention, the freeze-drying method in step (2) is: the obtained reaction mass is placed in a refrigerator at-20 ℃ for 12h, and then placed in a vacuum freeze drying oven, wherein the freeze drying conditions are as follows: the temperature is minus 80 ℃, the vacuum degree is 8.5Pa, and the freeze drying is carried out for 48 hours.
The invention provides a nano copper oxide/carbon nitride composite material for controlling water bloom, which is prepared by the preparation method.
The invention provides a method for using the nano copper oxide/carbon nitride composite material to inhibit the growth of algae and remove algal toxins.
In one embodiment of the invention, the method for inhibiting the growth of algae and removing algal toxins by using the nano copper oxide/carbon nitride composite material comprises the following steps: and (3) adding the nano copper oxide/carbon nitride composite materials with different copper loading amounts into the water bloom algae suspension, and exposing for 24-96 hours.
In one embodiment of the invention, the exposure conditions are: the light intensity is 312 mu mol/m for 14 hours each day and 10 hours in darkness2/s。
In one embodiment of the invention, the loading amount of Cu in the nano copper oxide/carbon nitride composite material is 0.02 wt%.
[ advantageous effects ]:
(1) the invention takes carbon nitride and copper acetate as raw materials, NaOH is added to react with copper ions to generate CuOH, and the CuOH is attached to C3N4In the method, the CuO is converted by calcination to obtain the nano copper oxide/carbon nitride composite material, compared with copper and carbon nitride, the nano copper oxide/carbon nitride composite material effectively improves the algae inhibition performance, and the copper load C prepared under the optimal copper load proportion3N4Has the algae inhibiting performance of C3N44.5 times of the total weight of the powder.
(2) The nano copper oxide/carbon nitride composite material prepared by the invention has stable performance, the algae inhibiting performance is less influenced by environmental factors, and the nano copper oxide/carbon nitride composite material still has good capability of controlling the water bloom in natural water with complex components.
(3) The reusability of the nano copper oxide/carbon nitride composite material prepared by the invention in natural water is higher than that of C3N4And more preferably.
(4) The nano copper oxide/carbon nitride composite material prepared by the invention can inhibit algae and can also quickly remove algae toxins.
Drawings
FIG. 1 is C prepared in example 13N4And different proportions of copper load C3N4TEM pictures of (a).
FIG. 2 shows a graph of C in example 23N4And different proportions of copper load C3N4The algae inhibiting performance is compared.
FIG. 3 shows the results of example 2C3N4And Cu-C3N4UV-vis-NIR DRS spectrogram of-3.
FIG. 4 shows a graph of C in example 23N4And Cu-C3N4-3 VB XPS spectrum.
FIG. 5 shows the concentrations C of example 33N4Graph of algal inhibition performance at different exposure times.
FIG. 6 shows Cu-C concentrations in example 33N4-3 plot of algal inhibition performance at different exposure times.
FIG. 7 shows a graph of C in example 43N4And Cu-C3N4-3 comparison of algal inhibition performance in natural water with that in culture medium.
FIG. 8 shows a graph of C in example 53N4And Cu-C3N4-3 reusability analysis of the plot in natural water.
FIG. 9 shows Cu-C in example 63N4-3 removal performance map for MC-LR under simulated natural light conditions.
FIG. 10 shows Cu-C in comparative example 13N4-3、CuSO4And a comparison graph of the algae inhibition performance of the CuO nano particles in natural water and a culture solution.
Detailed Description
The invention is further described with reference to specific examples.
The following examples are not provided to limit the scope of the present invention, nor are the steps described to limit the order of execution. Modifications of the invention which are obvious to those skilled in the art in view of the prior art are also within the scope of the invention as claimed.
[ example 1 ]
1. Preparing copper-loaded carbon nitride with different copper mass ratios:
putting 15g of urea into a muffle furnace, heating to 550 ℃ at the temperature rising speed of 2 ℃/min, and keeping heating at 550 ℃ for 4 hours; and then naturally cooling to room temperature, washing the obtained white product with ethanol and distilled water for three times, and removing unreacted urea. Then, take 1Dispersing the white product in 400mL of distilled water, performing ultrasonic treatment at 500W for 8h, centrifuging at 3000rpm for 10min to remove large particulate matter not peeled off, and freeze-drying the product completely peeled off to obtain purified C3N4The freeze drying method comprises the following steps: the obtained reaction mass is placed in a refrigerator at-20 ℃ for 12h, and then placed in a vacuum freeze drying oven, wherein the freeze drying conditions are as follows: the temperature is minus 80 ℃, the vacuum degree is 8.5Pa, and the freeze drying is carried out for 48 hours.
Respectively taking 64mg of purified C3N4Disperse into 0.00, 0.05, 0.10, 0.20, 0.50mM cupric acetate solution, shake the mixture for 10h to mix completely. Subsequently, 1mL of 1M NaOH was added to the above mixture, sonicated at 500W for 0.5h, centrifuged to remove the solid mixture and dried at 80 ℃. And (3) placing the dried mixture into a muffle furnace, heating to 550 ℃ at the temperature rising speed of 2 ℃/min, and keeping heating at 550 ℃ for 4 h. Washing the obtained yellow product with distilled water for three times, and freeze-drying, wherein the freeze-drying method is the same as the method in the previous paragraph, to obtain carbon nitride with copper mass ratio of 0, 0.005, 0.01, 0.02, 0.05Cu wt%, and they are named as C3N4、Cu-C3N4-1、Cu-C3N4-2、Cu-C3N4-3、Cu-C3N4-4。
2. Characterization test:
using Transmission Electron Microscope (TEM) for C3N4、Cu-C3N4-1、Cu-C3N4-2、Cu-C3N4-3、Cu-C3N4Characterization of morphology and size of-4, FIG. 1 is C prepared in example 13N4And different proportions of copper load C3N4TEM pictures of (a). The results show that C3N4、Cu-C3N4-1、Cu-C3N4-2、Cu-C3N4-3、Cu-C3N4The lateral dimensions of-4 were all about 1 μm, with more nanoparticles supported on C as the copper loading increased3N4Surface, SAED analysis results showed that the loaded nanoparticles were copper oxide nanoparticles.
[ example 2 ]
The nano copper oxide/carbon nitride composite material is used for inhibiting the growth of algae:
taking the suspension of the microcystis aeruginosa, wherein the initial density of the microcystis aeruginosa is 1.8 × 106cells/mL, algae cells were cultured in 1/2BG11 medium.
10mL of the solution with the concentration of 100mg/LC3N4、Cu-C3N4-1、Cu-C3N4-2、Cu-C3N4-3、Cu-C3N4The suspension of-4 was added to 90mL of algal cell culture medium, and shaking was maintained at 200rpm/min during the culture. The light time and dark time per day were: 14 and 10 hours, the illumination intensity is 312 mu mol/m2And s. After exposure for 96h, the number of the algae cells is counted by using a blood counting chamber, and the inhibition rate of various materials on the growth of the algae cells is determined. FIG. 2 is C3N4And different proportions of copper load C3N4The result shows that the copper load is obviously increased by C compared with the copper without load3N4Has an algae inhibiting property of, and Cu-C3N4The effect is best (see figure 2), 0.02Cu wt% is the best load, and the inhibition rate can reach 96%. To C3N4And Cu-C3N4-3, respectively carrying out light utilization efficiency and hole energy level tests to obtain C3N4And CuC3N4UV-vis-NIR DRS spectrogram of-3 (FIG. 3), C3N4And Cu-C3N4VB XPS spectrum of-3 (FIG. 4), analyzed by the graph, Cu-C3N4The reason why the algal inhibitive performance of-3 is more likely is that Cu-C3N4-3 has higher visible light utilization (fig. 3) and higher hole oxidation potential (fig. 4).
[ example 3 ]
C at different concentrations and different exposure times3N4And Cu-C3N4-3 algal inhibition:
the suspension and exposure conditions of microcystis aeruginosa were the same as in example 2.
The half effect concentration calculation method comprises the following steps:
with C3N4Or Cu-C3N4-3 calculating a regression equation and correlation coefficient for each treatment concentration using the logarithm of 10 of the treatment concentration as the abscissa and the inhibition rate of algal cells at different treatment concentrations as the ordinate, the corresponding treatment concentration value being the median effect concentration at an inhibition rate of 50%.
Mixing different concentrations (0, 1, 5, 10, 20, 50, 100mg/L) of C3N4And Cu-C3N4-3 adding to the suspension of microcystis aeruginosa, after 24, 48, 72, 96h exposure respectively, counting the number of algae cells using a blood count plate and calculating the half effect concentration of the two materials, fig. 5 for different concentrations C3N4FIG. 6 is a graph of algal inhibition performance under different exposure times, and Cu-C concentrations3N4-3 plot of algal inhibition performance at different exposure times. The results show that C3N4And Cu-C3N4Half effect concentrations of-3 at 72h were 56.4mg/L and 12.5mg/L, respectively, thus Cu-C3N4The algal inhibiting property of-3 is C3N44.5 times of the total weight of the powder.
[ example 4 ]
C3N4And Cu-C3N4-3 algal inhibition in natural waters:
the suspension and exposure conditions of microcystis aeruginosa were the same as in example 2.
Is selected from natural water (natural water), and is taken from Taihu lake water with serious water bloom, and the DOM content of the Taihu lake water is 15.3 mg/L. The Medium (Medium) was selected and 1/2BG-11 Medium was used. Adding Microcystis aeruginosa into natural water and nutrient solution suspension, respectively, adding 100mg/L of C prepared in example 13N4And Cu-C3N4-3 adding into suspension of natural water and nutrient solution of Microcystis aeruginosa respectively, exposing for 96h, and counting and analyzing the number of algae cells. FIG. 7 is C3N4And Cu-C3N4-3 ofAnd (3) an algae inhibition performance comparison graph in natural water and a culture medium. The results show that C is in the natural water body3N4The algae inhibiting performance is obviously inhibited, but Cu-C3N4-3 the algae inhibiting performance in the real water body is not obviously different from the algae inhibiting performance in the culture solution, which shows that Cu-C3N4-3 is little affected by natural water.
[ example 5 ]
C3N4And Cu-C3N4-3 reusability in natural water:
the suspension and exposure conditions of microcystis aeruginosa were the same as in example 2.
Under natural water conditions (natural water from the Taihu lake water area with severe water bloom, with DOM content of 15.3mg/L), cycle one (cycle 1): adding Microcystis aeruginosa into natural water, and exposing the Microcystis aeruginosa to 100mg/L C3N4、Cu-C3N4-3, exposure for 96h, counting algal cells; cycle two (cycle 2) C in cycle13N4And Cu-C3N4-3, collecting, washing 3 times with 75% ethanol and distilled water, respectively, exposing to algae cells again for 96h, and counting the algae cells; cycle three (cycle 3) C in cycle 23N4And Cu-C3N4-3, collecting, washing 3 times with 75% ethanol and distilled water, respectively, exposing to algae cells again for 96h, and counting the algae cells. FIG. 8 is C3N4And Cu-C3N4-3 reusability analysis of the plot in natural water. The results show that relative to C3N4，Cu-C3N4-3 has better reusability.
[ example 6 ]
Cu-C3N4-3 algal toxin degrading properties:
adding 100mg/L Cu-C into 50 μ g/L microcystin (MC-LR)3N4-3, placing for 1h in dark conditions to reach adsorption equilibrium, and then placing in a simulated natural visible light (100W xenon lamp, lambda)>420nm) under different irradiationAfter this time, the remaining MC-LR concentrations were measured using a Microcystin ELISA kit by filtration on a 0.22 μm filter. FIG. 9 is Cu-C3N4-3 removal performance map for MC-LR under simulated natural light conditions. The results show that Cu-C3N4-3 the concentration of algal toxins has been degraded to below 20 μ g/L within 24 hours, indicating Cu-C3N4-3 has a very good ability to degrade algal toxins.
Comparative example 1
2mgCu/L (corresponding to 100mg/L of Cu-C)3
FIG. 10 shows Cu-C3N4-3、CuSO4And a comparison graph of the algae inhibition performance of the CuO nano particles in natural water and a culture solution. The results showed that, in the culture medium, 2mgCu/L of CuO nanoparticles and CuSO4The growth inhibition rate of the microcystis aeruginosa is only 6.1 percent and 51.8 percent, which is far lower than that of Cu-C3N496.4% of-3; 2mgCu/L of CuO nanoparticles and CuSO in natural water4The growth inhibition rate of the microcystis aeruginosa is only 7.7 percent and 16.0 percent, which is far lower than that of Cu-C3N494.1% of-3. Indicating that the algae inhibiting performance of low-concentration copper is poor, but the same amount of copper is loaded on C3N4Can greatly improve the algae inhibiting performance.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention, and therefore the scope of the invention should be determined by the appended claims).