A material for treating water bloom phenomenon by photocatalysis method, a preparation method and application thereof

Abstract

The application discloses a material for treating water bloom by a photocatalytic method, a preparation method and application of the material, and the preparation method comprises the following steps: adding bismuth nitrate, iron nitrate and polydiallyldimethylammonium chloride into ethylene glycol, heating and reacting, and the reaction condition is that the ethylene glycol is refluxed and heated at 150-200 DEG C for 2-6 hours; after cooling, centrifugation and washing are carried out, the obtained precipitate is dried, and the obtained material is Fe-doped BiOCl, namely Fe-BiOCl; wherein the adding ratio of the bismuth nitrate, the iron nitrate, the polydiallyldimethylammonium chloride and the ethylene glycol is 60-100 mg: 30-50 mg: 3-6 mL: 60-100 mL. The application provides a preparation method of the functional material Fe-BiOCl for treating water bloom, and the functional material prepared by the method can effectively inhibit the formation of algae under the photocatalytic action, and is especially suitable for treating blue-green algae bloom.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of algae treatment, in particular to a material for treating water bloom phenomenon by photocatalysis method, a preparation method and application thereof. BACKGROUND

[0002] Water bloom refers to a natural ecological phenomenon of large-scale reproduction of algae in freshwater bodies, which is the main feature of water eutrophication. It is a phenomenon that blue-green algae (such as microcystis, fishy algae, tremella, pearl algae, blue ball algae, and hair algae) and green algae, diatoms, etc. reproduce in large quantities, making the water body appear blue or green. Accumulation of nitrogen and phosphorus nutrients in lake water bodies and the influence of other external pollutants can easily lead to nutrient accumulation in the lake, blue-green algae bloom phenomenon, which seriously damages the harmonious development of the ecological system and affects the function of the landscape water body and the health of the surrounding plants and animals.

[0003] At present, the domestic algae treatment methods include physical method, direct removal of harmful algae in water body, mainly including mechanical algae removal method, clay algae removal method, ultrasonic method, filtration and air floatation algae removal, etc.

[0004] There is also a chemical method, which uses chemical drugs to remove algae in eutrophic water bodies, mainly including flocculation precipitation method, chemical agent algae removal method and oxidant algae removal method, and biological method, that is, using the food chain and nutrient competition relationship between organisms and their interaction to control blue-green algae bloom.

[0005] At present, there is no report on using Fe-BiOCl functional material to treat water bloom phenomenon. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a new material for treating water bloom phenomenon, a preparation method and application thereof, so that it can form an effective inhibitory effect on algae under photocatalysis.

[0007] To solve the above technical problems, the present application adopts the following technical solutions:

[0008] On the one hand, the present application provides a preparation method of a material for treating water bloom phenomenon by photocatalysis method, comprising:

[0009] Bismuth nitrate, ferric nitrate and polydiallyldimethylammonium chloride are added to ethylene glycol for heating and reaction, and the reaction conditions are as follows: reflux heating at 150-200℃ for 2-6h; after cooling, centrifugation and washing are carried out, and the obtained precipitate is dried to obtain the material Fe-doped BiOCl, i.e. Fe-BiOCl;

[0010] The addition ratio of bismuth nitrate, ferric nitrate, polydiallyl dimethyl ammonium chloride, and ethylene glycol is 60-100mg: 30-50mg: 3-6mL: 60-100mL.

[0011] As a further improvement of the present invention, the addition ratio of bismuth nitrate, ferric nitrate, polydiallyl dimethyl ammonium chloride and ethylene glycol is 60-97 mg: 30-40 mg: 3-4.8 mL: 80-90 mL.

[0012] Furthermore, the reaction conditions are reflux heating at 170-200℃ for 2-4 hours.

[0013] On the other hand, the present invention also provides a material for controlling algal blooms using a photocatalytic method, which is prepared by the above-described preparation method.

[0014] In another aspect, the present invention also provides an application of a material for controlling algal blooms using a photocatalytic method, wherein the material is prepared by the above-mentioned preparation method; and the application is to control algal blooms using a photocatalytic method.

[0015] Furthermore, the aforementioned algal bloom is a cyanobacterial bloom.

[0016] Furthermore, the aforementioned bloom is a Microcystis bloom.

[0017] Furthermore, the bloom is a Microcystis aeruginosa bloom.

[0018] Furthermore, the application concentration of the material is 2-100 μg / mL; the initial liquid algal cell density is 5 × 10⁻⁶. 6 per mL.

[0019] Furthermore, the application concentration of the material is 5-20 μg / mL, and the application reaction time is 5-7 days.

[0020] By adopting the above technical solution, the present invention has at least the following advantages:

[0021] This invention provides a method for preparing Fe-BiOCl, a functional material for controlling algal blooms. The functional material prepared by this method can effectively inhibit algal blooms under photocatalysis, and is especially suitable for controlling cyanobacterial blooms. Attached Figure Description

[0022] The above is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a scanning electron image of the synthesized Fe-BiOCl material;

[0024] Figure 2 This is a graph showing the color changes of algal solutions in the control group and each experimental group at different reaction times;

[0025] Figure 3 These are confocal fluorescence microscopy images: Microcystis aeruginosa solution (ac) after 5 days of reaction and Microcystis aeruginosa solution (ef) treated with 20 μg / mL Fe-BiOCl; Left: Fluorescence field; Middle: Superimposed field; Right: Original field, magnification 100x;

[0026] Figure 4 It is a Fourier transform infrared spectrum;

[0027] Figure 5 The changes in OD values ​​of algal solutions in the control group, experimental group, and blank group within the range of 300-800 nm at different time points (a: 0d; b: 5d, and all samples were diluted by one time with BG-11 medium).

[0028] Figure 6 The changes in photosynthetic pigment OD values ​​in algal solutions of the control group, experimental group, and blank group at different time points (a: carotenoids; b: xanthophyll; c and d: chlorophyll);

[0029] Figure 7 The algal cell inhibition rate of the three experimental groups at different time points;

[0030] Figure 8 This is a color change graph of lake water samples at different exposure times, showing the control group (YH) and experimental groups (YHM1C1, YHM1C2, YHM1C3). Detailed Implementation

[0031] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that a more thorough understanding of the invention will be achieved and that the full scope of the invention will be conveyed to those skilled in the art.

[0032] Example 1

[0033] 60 mg of bismuth nitrate, 30 mg of ferric nitrate, and 3 mL of polydiallyldimethylammonium chloride were added to 60 mL of ethylene glycol and heated to react under the following conditions: reflux heating at 150 °C for 6 h. After cooling, the mixture was centrifuged, washed, and the resulting precipitate was dried. The obtained material was Fe-doped BiOCl, i.e., Fe-BiOCl.

[0034] Example 2

[0035] Bismuth nitrate 100 mg, iron nitrate 50 mg and poly diallyl dimethyl ammonium chloride 6 mL were added into ethylene glycol 100 mL to react under the following conditions: 200 °C reflux heating for 2 h; after cooling, centrifugation and washing were performed, and the obtained precipitate was dried to obtain the material Fe-doped BiOCl, i.e. Fe-BiOCl.

[0036] Example 3

[0037] Bismuth nitrate 90 mg, iron nitrate 40 mg and poly diallyl dimethyl ammonium chloride 5 mL were added into ethylene glycol 80 mL to react under the following conditions: 180 °C reflux heating for 4 h; after cooling, centrifugation and washing were performed, and the obtained precipitate was dried to obtain the material Fe-doped BiOCl, i.e. Fe-BiOCl.

[0038] Example 4

[0039] Bismuth nitrate 97 mg, iron nitrate 40 mg and poly diallyl dimethyl ammonium chloride 4.8 mL were added into ethylene glycol 90 mL to react under the following conditions: 170 °C reflux heating for 4 h; after cooling, centrifugation and washing were performed, and the obtained precipitate was dried to obtain the material Fe-doped BiOCl, i.e. Fe-BiOCl, the scanning electron image of which is shown in Figure 1 , and Figure 1 a sheet-like folded structure can be seen.

[0040] The material prepared in Example 4 was used to perform the following experiments.

[0041] Microcystis aeruginosa (FACHB-905) was purchased and cultured in a constant temperature and light incubator, the culture temperature was 25±0.5 °C, and the light and dark time ratio was 15 h:9 h, and the culture was shaken 2-3 times a day. Three experimental groups were set up: 50 μL, 100 μL and 200 μL of 1 mg / mL Fe-BiOCl solution was added to 10 mL of Microcystis aeruginosa liquid, respectively, and the concentrations were 5 μg / mL, 10 μg / mL and 20 μg / mL, respectively, and the control group was blank algal liquid, and each group was repeated 3 times. The initial algal liquid algal cell density was about 5×10 6 million / mL, and the color change of the algal liquid was observed every 24 h during the experiment, and the OD680 value of the algal liquid of each group was measured.

[0042] The color changes of the algal liquid of the control group and each experimental group under different reaction times are shown in Figure 2 . The color of the algal liquid of the control group and each experimental group became darker with the increase of exposure time. Compared with the control group, the color of the algal liquid of each experimental group gradually became lighter with the increase of time. When the exposure time was the same, the color of the algal liquid gradually became lighter with the increase of the concentration of the material.

[0043] Microcystis aeruginosa can produce photosynthetic pigments such as chlorophyll A during photosynthesis, which can produce fluorescence signals. Confocal fluorescence microscopic imaging method was used to investigate the morphology of algal cells in the control group and the algal liquid treated with 20 μg / mL Fe-BiOCl for 5 days. The excitation wavelength was 405 nm, and the emission wavelength was 420-600 nm, as shown in Figure 3 . The control group algal liquid for 5 days is shown in FIGS. a-c. It was observed that the algal cell morphology was regular round, with cell wall, and some growing and differentiating algal cells and a small amount of dead cells, and the fluorescence signal was strong. In the 20 μg / mL Fe-BiOCl treated Microcystis aeruginosa, the algal cell wall was thin or not visible, the algal cell size was reduced, a large number of algal cells appeared incomplete, collapsed, shrunk, and the differentiated algal cells were less, and the fluorescence signal was weakened, indicating that the material had an inhibitory effect on Microcystis aeruginosa under visible light irradiation.

[0044] In order to investigate the effect of Fe-BiOCl on the structure of algal cells, the control group algal liquid and the algal liquid treated with 20 μg / mL Fe-BiOCl for 5 days were dried into powder under low temperature and vacuum, and the changes of functional groups were analyzed by Fourier transform infrared spectroscopy, as shown in Figure 4 . In the control group, 3400 cm -1 belongs to γ-OH, 2930 cm -1 belongs to γ as C-H, 1650 cm -1 belongs to Amide I (γC=O), 1540 cm -1 belongs to Amide II (δN-H). In the experimental group, Amide II has a blue shift, indicating that Fe-BiOCl interacts with algal protein.

[0045] In order to investigate the photocatalytic inhibition effect of visible light catalytic material Fe-BiOCl on Microcystis aeruginosa, the changes of OD680 value of algal liquid at different culture times were analyzed by enzyme marker, and the scanning range was 300-800 nm, as shown in Figure 5 . Three experimental groups were set: the concentration of Fe-BiOCl in the algal liquid was 5 μg / mL, 10 μg / mL, and 20 μg / mL, respectively; three blank groups: the concentration of Fe-BiOCl in the BG-11 culture medium was 5 μg / mL, 10 μg / mL, and 20 μg / mL, respectively; at the same time, the control group algal liquid did not add any material, and each group was repeated three times. Among them, the samples of the three experimental groups were diluted by one time of BG-11 culture medium due to the high OD680 value. The results showed that: Fe-BiOCl material had no interference with the absorption of algal liquid, the OD680 value of all samples increased after 5 days of reaction, the OD680 value of the three experimental groups was lower than that of the control group, among them, the OD680 value of the 20 μg / mL Fe-BiOCl experimental group was the highest, indicating that the material had the most obvious inhibitory effect on the algal liquid at this concentration.

[0046] Chlorophyll, lutein, carotenoid are photosynthetic pigments in Microcystis aeruginosa, and the corresponding OD values are 645 nm and 663 nm (chlorophyll), 454 nm (lutein), and 444 nm (carotenoid). The concentration level reflects the growth of algae, and further analysis can see the influence of Fe-BiOCl photocatalytic material on each photosynthetic pigment. The changes of OD values of each photosynthetic pigment in the algae liquid under different reaction times (0d, 1d, 2d, 3d, 5d, 7d) were analyzed by enzyme marker, as shown in Figure 6 Three experimental groups were set: the concentration of Fe-BiOCl in the algae liquid was 5 μg / mL, 10 μg / mL, and 20 μg / mL respectively; three blank groups: the concentration of Fe-BiOCl in the BG-11 medium was 5 μg / mL, 10 μg / mL, and 20 μg / mL respectively; and the control group was blank algae liquid, with each group repeated three times. The results showed that the OD values of each photosynthetic pigment in the algae liquid gradually increased with time; when the time was the same, the OD values of each photosynthetic pigment in the algae liquid gradually decreased with the increase of the concentration of the material; and when the reaction was for 7d, the inhibition of 20 μg / mL Fe-BiOCl on each photosynthetic pigment in the algae liquid was the most obvious.

[0047] On this basis, the algae inhibition rate of each experimental group was calculated, as shown in Figure 7 On the 7th day, the inhibition rate of 20 μg / mL Fe-BiOCl on the algae cells was the highest, and the best algae removal rate was about 18%.

[0048] In order to investigate the application of Fe-BiOCl to the actual sample of water affected by Microcystis aeruginosa, a lake water sample with vigorous growth of Microcystis aeruginosa in summer was collected and placed in a constant temperature and light incubator for continuous light, with shaking 2-3 times a day. Three experimental groups were set: 50 μL, 100 μL, and 200 μL of 1 mg / mL Fe-BiOCl solution were added to 10 mL of actual water sample respectively, with the concentrations being 5 μg / mL (marked as YHM1C1), 10 μg / mL (marked as YHM1C2), and 20 μg / mL (marked as YHM1C3) respectively, and the control group was without the addition of the material (marked as YH), with each group repeated three times. The color changes of the control group and the experimental groups were observed at 0h, 18h, 42h, 66h, 114h, and 162h. The color changes of the control group and each experimental group under different reaction times are shown in Figure 8 The color of the control group and each experimental group became darker with the increase of exposure time. Compared with the control group, the color of the actual sample in each experimental group gradually became lighter with the increase of time. When the exposure time was the same, the color of the actual sample gradually became lighter with the increase of the concentration of the material.

[0049] The material prepared in Example 4 is used in the above experiment process only, the material prepared in Examples 1-3 can also produce similar effects. And although the above experiment process only gives the treatment effect of higher concentration of Microcystis aeruginosa, but based on its treatment mechanism, it is expected that other blue-green algae, such as Anabaena, Oscillatoria, Nostoc, Chroococcus, and Nori, as well as green algae, diatoms, and other algae in freshwater bodies, can produce similar treatment effects.

[0050] The above is only a preferred embodiment of the present application, not any form of limitation on the present application, and those skilled in the art can make some simple modifications, equivalent changes or modifications based on the above disclosed technical content, which are all within the protection scope of the present application.

Claims

1. A method for preparing a material for controlling algal blooms using photocatalysis, characterized in that, include: Bismuth nitrate, ferric nitrate, and polydiallyldimethylammonium chloride were added to ethylene glycol and heated to react under the following conditions: reflux at 150-200℃ for 2-6 hours. After cooling, the material is centrifuged and washed, and the precipitate is dried to obtain Fe-doped BiOCl, i.e., Fe-BiOCl. The addition ratio of bismuth nitrate, ferric nitrate, polydiallyl dimethyl ammonium chloride, and ethylene glycol is 60-100mg: 30-50mg: 3-6mL: 60-100mL.

2. The method for preparing the material for controlling algal blooms using photocatalysis according to claim 1, characterized in that, The addition ratio of bismuth nitrate, ferric nitrate, polydiallyl dimethyl ammonium chloride, and ethylene glycol is 60-97 mg: 30-40 mg: 3-4.8 mL: 80-90 mL.

3. The method for preparing the material for controlling algal blooms using photocatalysis according to claim 1 or 2, characterized in that, The reaction conditions are reflux heating at 170-200℃ for 2-4 hours.

4. A material for controlling algal blooms using photocatalysis, characterized in that, It is prepared by the preparation method according to any one of claims 1-3.

5. An application of a material for controlling algal blooms using photocatalysis, characterized in that, The material is the material prepared by the preparation method according to any one of claims 1-3, or the material according to claim 4; The application involves using photocatalysis to control algal blooms.

6. The application of the material for controlling algal blooms using photocatalysis as described in claim 5, characterized in that, The algae bloom is described as a cyanobacterial bloom.

7. The application of the material for controlling algal blooms using photocatalysis as described in claim 6, characterized in that, The algal bloom is described as a Microcystis bloom.

8. The application of the material for controlling algal blooms using photocatalysis according to claim 7, characterized in that, The bloom is a Microcystis aeruginosa bloom.

9. The application according to any one of claims 5-8, characterized in that, The application concentration of the material is 2-100 μg / mL; the initial liquid algal cell density is 5 × 10⁻⁶. 6 per mL.

10. The application according to claim 9, characterized in that, The application concentration of the material is 5-20 μg / mL, and the application reaction time is 5-7 days.

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