Preparation process of WRF-nZVI and algae removal method of WRF-nZVI

Abstract

The invention relates to a WRF-nZVI preparation process which comprises the following steps: culturing white rot fungi, preparing 200ml of potato glucose water by using a 500ml conical flask, carrying out high-pressure sterilization in a high-pressure sterilization pot at 121 DEG C for 15 minutes, cooling the sterilized potato glucose water to 20-25 DEG C, and carrying out high-pressure sterilization in a high-pressure sterilization pot at 121 DEG C for 15 minutes, so as to obtain the WRF-nZVI. The method comprises the following steps: inoculating white rot fungi subjected to plate culture into a conical flask filled with sterilized potato glucose water under a sterile condition, and then carrying out shake culture under the conditions of 30 DEG C and 150 r / min until the logarithmic phase; nZVI with the concentration of 12.5 g / L is added into a conical flask at a time, coupling culture is conducted for 30 min under the same condition, after culture is finished, a culture medium is filtered and removed, a 0.9% NaCl solution is used for rapid flushing, obtained composite fungus pellets (WRF-nZVI) are collected, the obtained WRF-nZVI is put into a water area needing cyanobacterial bloom treatment, iron nanoparticles are evenly distributed on the surface of white rot fungi, and the composite fungus pellets are obtained. The algae-lysing capability on the microcystis aeruginosa can be enhanced, and the algae removal efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of Microcystis aeruginosa removal, and more particularly to a WRF-nZVI preparation process and algae removal method thereof. Background Technology

[0002] Eutrophication is a phenomenon caused by the excessive loading and accumulation of nutrients such as nitrogen and phosphorus in water bodies, leading to an imbalance in the distribution of species in aquatic ecosystems. This results in frequent algal blooms, decreased biodiversity, and weakened ecological functions, damaging and degrading aquatic ecosystems, leading to water quality deterioration, drinking water shortages, and endangering ecological security and public health. Cyanobacterial blooms are particularly prominent in eutrophication, posing a threat to aquatic ecosystems and human health. Microcystis aeruginosa is a common algae causing cyanobacterial blooms. Existing methods for controlling cyanobacterial blooms include physical methods, which are simple to operate but costly, energy-intensive, and may cause algal toxin leaks; these are typically suitable for large-scale outbreaks. Chemical methods are effective at killing cyanobacteria but produce disinfection byproducts, posing secondary pollution. Biological methods are environmentally friendly, produce no secondary pollution, are specific, and low-cost, but are usually slow to take effect, time-consuming, inefficient, and subject to many limiting factors. Summary of the Invention

[0003] The purpose of this invention is to provide a WRF-nZVI preparation process and algae removal method, which addresses the problems of unstable algae control effect, high operating cost and secondary pollution caused by algae dissolution in current cyanobacterial blooms, and develops a stable, efficient and safe algae control method.

[0004] To achieve the above objectives, the technical solution adopted by this invention is: a WRF-nZVI preparation process, comprising the following steps: Step 1: Cultivation of white rot fungus. Prepare 200ml of potato dextrose solution in a 500ml Erlenmeyer flask. Autoclave the solution at 121℃ for 15 minutes. After sterilization, cool the potato dextrose solution to 20-25℃. Under aseptic conditions, inoculate the white rot fungus cultured on plates into the Erlenmeyer flask containing the sterilized potato dextrose solution. Then, culture the solution at 30℃ and 150 rpm with shaking until the logarithmic growth phase (OD range 0.772-1.313). Step 2: Compounding. Add 12.5 g / L of nZVI to the conical flask from Step 1 and couple culture for 30 min under the same conditions. After the culture is completed, filter and discard the culture medium, rinse quickly with 0.9% NaCl solution, and collect the resulting compound bacterial balls (WRF-nZVI).

[0005] Another technical solution of the present invention is: a WRF-nZVI algae removal method, wherein the obtained WRF-nZVI is put into the water area where cyanobacterial bloom control is required.

[0006] Preferably, the amount of WRF-nZVI added is 12.5 g / L.

[0007] Preferably, the pH for algae removal treatment is 7.

[0008] Preferably, the temperature for algae removal treatment is 30°C.

[0009] The technical effects of this invention are as follows: Nano-zero valent iron exhibits high reactivity and excellent performance in water pollution control, but it is prone to aggregation and oxidation. White-rot fungi can degrade various pollutants, but the degradation cycle is long and easily affected by environmental factors. In the WRF-nZVI preparation process of this invention, iron nanoparticles are uniformly distributed on the surface of white-rot fungi, and nano-zero valent iron is loaded onto the white-rot fungi to achieve coupling, alleviating the oxidation and aggregation of nano-zero valent iron, thus achieving a synergistic effect greater than the sum of its parts, enhancing the algicidal ability against Microcystis aeruginosa, and improving algae removal efficiency.

[0010] The design of the dosage, pH value, and reaction temperature can be combined with the performance of WRF-nZVI to achieve more efficient algae removal. Attached Figure Description

[0011] Figure 1 SEM image, EDS energy spectrum and elemental distribution map of WRF-nZVI.

[0012] Figure 2 The figure shows the effect of WRF-nZVI dosage on the removal rate of Microcystis aeruginosa.

[0013] Figure 3 The effect of pH on the removal rate of Microcystis aeruginosa.

[0014] Figure 4 The figure shows the effect of reaction time on the removal rate of Microcystis aeruginosa.

[0015] Figure 5 The effect of reaction temperature on the removal rate of Microcystis aeruginosa. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way. Example 1

[0017] A process for preparing WRF-nZVI was described. The preparation experiment was conducted in a 500ml Erlenmeyer flask. White rot fungi were cultured in liquid. 200ml of potato dextrose solution was prepared in a 500ml Erlenmeyer flask and autoclaved at 121℃ for 15min. After autoclaving, the potato dextrose solution was cooled to 20-25℃. Under aseptic conditions, the white rot fungi cultured on plates were inoculated into the Erlenmeyer flask containing the sterilized potato dextrose solution. The mixture was then shaken and cultured at 30℃ and 150r / min until the logarithmic growth phase (OD range of 0.772-1.313). Then, a pre-prepared concentration of 12.5g / L of nZVI was added at once, and the mixture was coupled and cultured under the same conditions for 30min. After the culture was completed, the culture medium was filtered out and discarded. The mixture was quickly washed with 0.9% NaCl solution, and the resulting composite bacterial balls (WRF-nZVI) were collected.

[0018] The SEM image, EDS spectrum, and elemental distribution map of the WRF-nZVI prepared in Example 1 are shown below. Figure 1 As shown, iron nanoparticles are uniformly distributed on the surface of white-rot fungi, indicating that nZVI was successfully loaded onto the white-rot fungi. Further confirmation of the elemental composition of WRF-nZVI by surface scan analysis revealed that WRF-nZVI mainly contains C, O, and Fe elements. Among them, Fe elements are relatively uniformly distributed on the surface of white-rot fungi without obvious aggregation, and the Fe content is 34.38%, indicating that nZVI has been successfully and uniformly loaded onto the surface of white-rot fungi in a dispersed form. Example 2

[0019] Six groups of water samples, each requiring Microcystis aeruginosa treatment, were collected (1000 ml). One group served as a control group, without the addition of the compound bacterial balls (WRF-nZVI) prepared in Example 1. The treatments for the other five groups are shown in the table below.

[0020] The results of this embodiment are as follows: Figure 2 As shown, when the WRF-nZVI dosage per 1L of water sample increased from 5g to 12.5g, the dissolution rate of *Microcystis aeruginosa* increased from 37.34% to 95.73%. Subsequently, when the WRF-nZVI dosage continued to increase from 12.5g to 15g, the dissolution rate of *Microcystis aeruginosa* decreased to 80.09%. This indicates that the highest removal rate of *Microcystis aeruginosa* was achieved at a WRF-nZVI dosage of 12.5g / L, and good removal rates were observed within the dosage range of 10-12.5g / L. Example 3

[0021] Five groups of water samples, each containing 1000 ml, were collected for treatment with Microcystis aeruginosa. The composite bacterial balls (WRF-nZVI) prepared in Example 1 were added to each sample. The specific treatment is shown in the table below:

[0022] The results of this embodiment are as follows: Figure 3 As shown, the WRF-nZVI algae control system achieved algae dissolution rates of 85.98%, 96.22%, 95.14%, 90.43%, and 83.19% for Microcystis aeruginosa at pH values ​​of 5, 6, 7, 8, and 9, respectively. This indicates that the WRF-nZVI algae control system exhibits good removal efficiency for Microcystis aeruginosa under different pH conditions, with removal rates exceeding 95% at pH=6 and pH=7. The algae dissolution rate decreases slowly and slightly with increasing pH. Example 4

[0023] Five groups of water samples, each containing 1000 ml, were collected for treatment with Microcystis aeruginosa. The composite bacterial balls (WRF-nZVI) prepared in Example 1 were added to each sample. The specific treatment is shown in the table below:

[0024] The results of this embodiment are as follows: Figure 4 As shown, when the reaction time was 0.5h, 1h, 1.5h, 2h, and 2.5h, the dissolution rate of Microcystis aeruginosa by the WRF-nZVI algae control system was 94.26%, 96.55%, 98.02%, 95.33%, and 91.29%, respectively. As the reaction time increased from 0.5h to 1.5h, the removal rate of Microcystis aeruginosa increased from 94.26% to 98.02%. When the reaction time increased from 1.5h to 2.5h, the removal rate decreased slightly.

[0025] Example 5 Five groups of water samples, each containing 1000 ml, were collected for treatment with Microcystis aeruginosa. The composite bacterial balls (WRF-nZVI) prepared in Example 1 were added to each sample. The specific treatment is shown in the table below:

[0026] The results of this embodiment are as follows: Figure 5 As shown, when the reaction temperature increased from 15℃ to 20℃, the dissolution rate of *Microcystis aeruginosa* increased from 65.32% to 92.29%. Further increasing the reaction temperature resulted in a continuous increase in the dissolution rate, reaching a peak of 95.89% at 30℃. Subsequent increases in reaction temperature led to a slight decrease in the dissolution rate. This indicates that the highest removal rate of *Microcystis aeruginosa* was achieved at a reaction temperature of 30℃.

[0027] Combined with Examples 1-5 and Appendix Figure 1-5It can be concluded that the WRF-nZVI preparation process of this application can prepare composite bacterial balls with iron nanoparticles uniformly distributed on the surface of white-rot fungi, with an Fe content of 34.38%. When applied to water algae treatment, it can achieve good removal effect of Microcystis aeruginosa. The algae removal efficiency can reach more than 90% when the dosage is 12.5 g / L, the pH is 6-7, the reaction temperature is 20-30℃, and the reaction time is 0.5-2.5 h. In particular, the removal rate of Microcystis aeruginosa is the highest when the dosage is 12.5 g / L, the pH is 7, the reaction temperature is 30℃, and the reaction time is 1.5 h.

[0028] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A WRF-nZVI preparation process, characterized in that, Includes the following steps: Step 1: Cultivation of white rot fungus. Prepare 200ml of potato glucose solution in a 500ml Erlenmeyer flask and autoclave it at 121℃ for 15min. After sterilization, cool the potato glucose solution to 20-25℃. Under aseptic conditions, inoculate the white rot fungus cultured on plates into the Erlenmeyer flask containing the sterilized potato glucose solution. Then, culture it with shaking at 30℃ and 150r / min until the logarithmic growth phase. Step 2: Compounding. Add 12.5 g / L of nZVI to the conical flask from Step 1 and couple culture for 30 min under the same conditions. After the culture is completed, filter and discard the culture medium, rinse quickly with 0.9% NaCl solution, and collect the resulting compound bacterial balls (WRF-nZVI).

2. A WRF-nZVI algae removal method, characterized in that, The WRF-nZVI obtained in claim 1 is applied to waters where cyanobacterial bloom control is required.

3. The WRF-nZVI algae removal method according to claim 2, characterized in that, The amount of WRF-nZVI added was 12.5 g / L.

4. The WRF-nZVI algae removal method according to claim 2, characterized in that, The pH for algae removal treatment is 7.

5. The WRF-nZVI algae removal method according to claim 2, characterized in that, The temperature for algae removal treatment is 30℃.

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