Polymer-based porous modified sponge and application thereof in red tide prevention and control
Through the preparation of polymer-based porous modified sponges, the high water absorption rate and load rate of adsorbing dissolved algae is solved, and the traditional red tide prevention and control methods are unstable, high cost and environmental pollution are achieved, and the red tide prevention and control effect is achieved with high efficiency, environmental protection and low cost.
Patent Information
- Application Number
- CN202510209737.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-25
- Publication Date
- 2025-05-27
AI Technical Summary
Traditional red tide prevention and control methods have unstable effects, high costs and may lead to environmental pollution.
A polymer-based porous modified sponge is used to form a polymer framework by cross-linking polyvinyl alcohol and formaldehyde, and modified with iron salt, to prepare a sponge material with high water absorption and loading rate for immobilizing adsorption and soluble algae.
It has achieved efficient reduction of red tide algae biomass, avoided chemical pollution, and the material has good physical stability and low cost, which is suitable for the prevention and control and prevention of red tide disasters.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of marine engineering materials, and particularly relates to a polymer-based porous modified sponge for red tide prevention and control and its application in red tide prevention and control. Background Art
[0002] Red tide is a complex ecological phenomenon caused by the massive reproduction of harmful microalgae in seawater, which poses serious hazards to fishery aquaculture, landscape tourism, coastal ecological security and even humans. How to efficiently and safely eliminate red tide organisms along the coast is a long-standing technical problem in the field of red tide control. The control strategies for red tide include physical, chemical, biological and natural mineral flocculation methods. Since organisms have the characteristics of a large variety, wide distribution, fast reproduction speed and environmental friendliness, using biological methods to treat red tide has great potential. Bacteria can not only inhibit the growth of algae by competing for nutrients with algae, but also inhibit the growth of algae or kill algae by secreting certain extracellular active substances into the environment. The algicidal mechanism of bacteria is mainly divided into direct algicidal and indirect algicidal. Direct algicidal means that algicidal bacteria attack algal cells by direct contact, and indirect algicidal is that algicidal bacteria secrete algicidal active substances to affect the growth of algae or kill algae. An appropriate application method is the key to the application effect of algicidal substances. There are four forms of application of algicidal substances: direct spraying, using algicidal functional substances, building reactors and carrier immobilization.
[0003] Microbial immobilization is a biotechnology that immobilizes microorganisms in a carrier through physical or chemical methods, thereby enhancing the activity of microorganisms and making them reusable; it has the advantages of low material price, simple production process, reusability, high impact resistance, and not being easily engulfed by other organisms under static water conditions; its methods include surface adsorption, pore filling, embedding method, crosslinking method and covalent method, etc.
[0004] Adsorbing cells onto carriers for bioremediation is the simplest, cheapest, and most commonly used immobilization method. It is based on the reversible physical interaction between bacteria and the carrier surface through weak binding forces. Factors affecting adsorption include: First, bacterial characteristics, such as physiological conditions and cell age, bacterial surface appendages, cell membrane charge, and hydrophobicity. Second, medium characteristics, such as its composition and pH value. Immobilized microorganisms can reduce the impact of external environmental changes on their activity, thereby extending their survival time in the environment. This is particularly important for the prevention and control of red tides in open waters because the environmental conditions in open waters change greatly; Third, the surface properties of the carrier matrix, including the size and structure of the adsorbent used, and the pores on the adsorbent. Compared with free cells, immobilized microorganisms have higher cell density and activity. Immobilized algicidal bacteria can release active substances concentrated in specific areas, more effectively inhibit algal growth, are easy to collect and reuse, improve the recyclability and reusability of microorganisms, and reduce operating costs. Therefore, it is particularly urgent to develop an efficient, environmentally friendly, and low-cost red tide prevention and control material and technology. Summary of the Invention
[0005] The problems existing in the prior art are that traditional red tide prevention and control methods often have problems such as unstable effects, high costs, and possible environmental pollution in practical applications. In view of these problems, the purpose of the present invention is to provide a polymer-based porous modified sponge for red tide prevention and control and its application in red tide prevention and control.
[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a polymer-based porous modified sponge, which is prepared by crosslinking polyvinyl alcohol and formaldehyde to form a polymer skeleton and adding iron salt for modification.
[0007] The second aspect of the present invention provides a preparation method of the above polymer-based porous modified adsorption sponge, including the following steps: S1: Mix polyvinyl alcohol with deionized water and stir at 95 °C until completely dissolved to obtain a polyvinyl alcohol solution; S2: Add an emulsifier to the polyvinyl alcohol solution in S1, stir and react at 60 °C for 10 min, then add formaldehyde and continue to stir and react at 60 °C for 20 min to obtain a reaction solution; S3: Add FeCl 3 , then add hydrochloric acid, stir and react at 60 °C for 60 min to obtain a functional composite solution; S4: Cure, dry, wash, and dry the functional composite solution in S3 to obtain a polymer-based porous modified sponge.
[0008] Further, the concentration of the above-mentioned polyvinyl alcohol solution is 9 wt% to 11 wt%.
[0009] Further, the above-mentioned emulsifier is Tween 80.
[0010] Further, the final concentration of the above-mentioned emulsifier is 3.5 wt% to 4.5 wt%.
[0011] Further, the final concentration of the above-mentioned formaldehyde is 3 wt% to 3.4 wt%.
[0012] Further, the above-mentioned FeCl 3 has a final concentration of 1 wt% to 3 wt%.
[0013] Further, the final concentration of the above-mentioned hydrochloric acid is 4 wt%.
[0014] The third aspect of the present invention provides the application of the above-mentioned polymer-based porous modified sponge in red tide prevention and control.
[0015] Further, the above-mentioned polymer-based porous modified sponge can reduce the biomass of red tide algae by immobilizing and adsorbing algicidal bacteria, thereby achieving the effect of preventing and controlling red tides.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared with traditional sponges, the present invention adds Fe ions for modification in the sponge, which can make the obtained sponge material have the characteristics of lower density and higher water absorption. This is because the modified porous sponge has a larger porosity and specific surface area, improving the loading rate. Fe ions have an attraction to Pseudomonas. The addition of Fe ions for modification in the present invention helps the sponge material to immobilize and adsorb algicidal bacteria solution and alleviate the dilution of algicidal bacteria by tides. The polymer-based porous modified sponge of the present invention also has good physical stability, is not easily degraded, and can maintain its structure in water for a long time. The polymer-based porous modified sponge of the present invention can effectively reduce the algae density by adsorbing and immobilizing algicidal bacteria solution. Therefore, it can be used not only during the outbreak of red tide disasters but also for daily prevention before the outbreak of red tide disasters. The polymer-based porous modified sponge of the present invention uses physical adsorption rather than chemical reaction to immobilize algicidal bacteria, avoiding the generation of chemical pollutants; and the preparation process is simple, the cost is relatively low, and it is easy to mass-produce. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is the SEM image of the polymer-based porous modified sponge.
[0018] Figure 2 is the SEM image of the polymer-based porous sponge.
[0019] Figure 3 is the performance comparison diagram of the polymer-based porous modified sponge and the polymer-based porous sponge.
[0020] Figure 4 It is the effect diagram of the polymer-based porous modified sponge adsorbing the bacterial liquid at different times.
[0021] Figure 5 It is the SEM image of the polymer-based porous modified sponge after adsorbing the algicidal bacterial liquid.
[0022] Figure 6 It is the fitting diagram of the adsorption kinetics of the polymer-based porous modified sponge.
[0023] Figure 7 It is the algicidal effect diagram when different volumes of algal liquid are added after 0.2 g of the polymer-based porous modified sponge adsorbs the algicidal bacteria. Specific implementation manners
[0024] The present invention will be further described in detail below in conjunction with specific embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0025] The CAS number of polyvinyl alcohol (PVA) involved in the following embodiments is 9002-89-5.
[0026] Example 1: A preparation method of a polymer-based porous modified sponge is carried out according to the following steps: S1: Mix polyvinyl alcohol with deionized water, and stir at 95 °C until completely dissolved to prepare a PVA solution with a concentration of 9 wt% to 11 wt%. S2: Add emulsifier Tween 80 with a final concentration of 3.5 wt% to 4.5 wt% to the PVA solution in S1, stir and react at 60 °C for 10 min, then add formaldehyde with a final concentration of 3 wt% to 3.4 wt%, and continue to stir and react at 60 °C for 20 min to obtain a reaction solution. S3: Add FeCl with a final concentration of 1 wt% to 3 wt% to the reaction solution in S2 3 , and then add hydrochloric acid with a final concentration of 4 wt%, stir and react at 60 °C for 60 min to obtain a functional composite solution. S4: After curing and drying the functional composite solution in S3 at 60-70 °C for 5 h, the obtained solid product is washed once with dishwashing liquid, then washed 3 times with deionized water, 5 min each time, and finally dried to constant weight at 60 °C to obtain the polymer-based porous modified sponge.
[0027] In order to screen out the optimal process conditions for preparing the polymer-based porous modified sponge in this example, the orthogonal experiment method is used for optimization. Experimental factors: Concentration of PVA solution (9wt%, 10wt%, 11wt%); Final concentration of emulsifier (3.5wt%, 4wt%, 4.5wt%); Final concentration of formaldehyde (3wt%, 3.2wt%, 3.4wt%); Final concentration of FeCl 3 (1wt%, 2wt%, 3wt%).
[0028] Experimental levels: Three different levels are selected for each factor.
[0029] Selection of orthogonal array: The orthogonal array L27(3 13 ) is selected, where L27 represents 27 trials.
[0030] Evaluation indexes: The test indexes include the density and water absorption rate of the polymer-based porous modified sponge.
[0031] As can be seen from Table 1, the optimal conditions for preparing the polymer-based porous modified sponge are: PVA solution concentration 9wt%, final concentration of formaldehyde 3.4wt%, final concentration of emulsifier 3.5wt%, FeCl 3 Final concentration is 1wt%.
[0032] Table 1 Comparative Example 1: A method for preparing a polymer-based porous sponge is carried out according to the following steps: S1: Mix polyvinyl alcohol with deionized water, and stir at 95°C until completely dissolved to prepare a PVA solution with a concentration of 9wt% - 11wt%; S2: Add emulsifier Tween 80 with a final concentration of 3.5wt% - 4.5wt% to the PVA solution in S1, stir and react at 60°C for 10 min, then add formaldehyde with a final concentration of 3wt% - 3.4wt%, and continue to stir and react at 60°C for 20 min to obtain a reaction solution; S3: After curing and drying the reaction solution in S2 at 60 - 70°C for 5 h, the obtained solid product is washed once with dishwashing liquid, then washed three times with deionized water, 5 min each time, and finally dried to constant weight at 60°C to obtain the polymer-based porous sponge.
[0033] In this example, in order to screen out the best process conditions for preparing the polymer-based porous sponge, the orthogonal experiment method is used for optimization.
[0034] Experimental factors: Concentration of PVA solution (9wt%, 10wt%, 11wt%); Final concentration of emulsifier (3.5wt%, 4wt%, 4.5wt%); Final concentration of formaldehyde (3wt%, 3.2wt%, 3.4wt%).
[0035] Experimental levels: Three different levels are selected for each factor.
[0036] Selection of orthogonal array: The orthogonal array L9(3 4 ) is selected, where L9 represents 9 trials.
[0037] Evaluation index: The test indexes include the density and water absorption rate of the polymer-based porous sponge.
[0038] As can be seen from Table 2, the optimal conditions for preparing the polymer-based porous sponge are: PVA solution concentration of 11wt%, final concentration of formaldehyde of 3wt%, and final concentration of emulsifier of 4.5wt%.
[0039] Table 2 Figure 1 SEM image of the polymer-based porous modified sponge prepared under the optimal conditions of Example 1 Figure 2 SEM image of the polymer-based porous sponge prepared under the optimal conditions of Comparative Example 1. As can be seen from the figure, the modification with Fe ions will increase the number of pores in the sponge material, the porosity increases from 80.74% to 81.88%, and the specific surface area becomes larger, which is beneficial to improving the loading rate (adsorption rate) of algicidal bacteria.
[0040] Example 2: The polymer-based porous modified sponge prepared under the optimal conditions of Example 1 and the polymer-based porous sponge prepared under the optimal conditions of Comparative Example 1 are respectively cut into cubes with a side length of 1 cm 3 , placed in an oven at 40°C and dried to a constant weight, then cooled to room temperature, and their masses are recorded as m 0 . Then they are placed in a dry and clean beaker, and water is added to completely submerge the sponges. After standing for 24 h, the test blocks are taken out, and the residual water on the surface of the test blocks is wiped off as much as possible with a wet cloth, and the mass of the test blocks is weighed and recorded as m g (accurate to 0.0001 g). Calculate the water absorption rate W R of the sponge material. The experiment is repeated three times. As can be seen from Figures 1 - 3 , the polymer-based porous modified sponge modified with Fe ions will not reduce its own sponge performance. Compared with the polymer-based porous sponge of Comparative Example 1, not only does the sponge material have more pores and a larger specific surface area, but its water absorption rate also increases significantly, which is beneficial to improving the efficiency of adsorbing and fixing algicidal bacteria.
[0041] Example 3: In this example, Karenia mikimotoi in the red tide was used as the experimental object, and the following steps were adopted to verify the algicidal effect of the polymer-based porous modified sponge immobilized with algicidal bacteria.
[0042] The polymer-based porous modified sponge prepared under the optimal conditions of Example 1 was placed in an oven at 40 °C until constant weight and then cooled to room temperature. After weighing 0.2 g of the sponge material and sterilizing it by ultraviolet radiation for 4 h, it was put into a shaking flask containing 100 ml of algicidal bacteria liquid in the exponential growth phase (Pseudoalteromonas sp. FDHY-MZ2, Zhong Y, Zheng W, Shi X, et al. Pilot-Scale Fermentation of Pseudoalteromonas sp. Strain FDHY-MZ2: An Effective Strategy for Increasing Algicidal Activity[J]. Biology(2079-7737), 2023, 12(11). DOI: 10.3390 / biology12111447.). The culture was carried out under the conditions of a liquid loading of 40%, a temperature of 20 °C, and a rotation speed of 150 rpm. The sponge material was taken out after culturing for 3 h, 6 h, 12 h, 24 h, and 48 h respectively. The sponge materials at different sampling time points were added to a sterile medium with an appropriate volume ratio of the same liquid absorption amount (2216E liquid medium + 0.5 wt% peptone + 1.5 wt% soluble starch; pH 7.5), and the absorbance was measured after ultrasonic treatment for 15 min. At the same time, the algicidal bacteria liquid at different sampling time points was appropriately diluted and placed in a cuvette, and the absorbance was measured at a wavelength of 600 nm to make its absorbance value within the range of 0.2 - 0.8. The dilution factor and absorbance value were recorded. Three parallels were set for each group.
[0043] Figure 4 is the absorbance of the polymer-based porous modified sponge adsorbing the bacteria liquid at different times. The amount of the bacteria liquid adsorbed by the polymer-based porous modified sponge basically reaches saturation at 24 h of adsorption, that is, 0.2 g of the polymer-based porous modified sponge can adsorb 6.45 OD of algicidal bacteria within 24 h 600 . Figure 5 is the SEM image of the polymer-based porous modified sponge after adsorbing algicidal bacteria. It can be seen from the figure that the algicidal bacteria are attached to the pore structure of the polymer-based porous modified sponge. Figure 6 is the pseudo-first-order and pseudo-second-order adsorption kinetic model of the polymer-based porous modified sponge. It can be seen from the figure that by comparing the pseudo-first-order and pseudo-second-order adsorption models, it can be concluded that the polymer-based porous modified sponge better conforms to the pseudo-second-order adsorption model. That is to say, the adsorption of the bacteria liquid by this material mainly involves chemical adsorption. It is inferred that the added iron ions during the modification enable the sharing or transfer of electron pairs between the bacteria liquid and the carrier surface, thus forming a strong chemical bond.
[0044] The sponge materials after adsorbing and immobilizing the algicidal bacteria for 24 h were respectively placed into 100 ml, 200 ml, 300 ml, 400 ml, and 500 ml of Karenia mikimotoi algal solutions in the exponential growth phase for co-culture, and samples were taken after 6 h, 12 h, and 24 h. Each time, 1 ml of the culture solution was taken for algal cell counting.
[0045] Figure 7 It is the algicidal effect diagram of the polymer-based porous modified sponge immobilized with adsorbed algicidal bacteria and put into algal solutions of different volumes of Karenia mikimotoi. As can be seen from the figure, when 0.2 g of the polymer-based porous modified sponge was put into 100 - 300 ml of algal solution in the exponential growth phase, 100% algicidal effect could be achieved within 12 h; after 24 h of placement, 94.7% algicidal effect could be achieved on 400 ml of Karenia mikimotoi algal solution, and only 68.42% algicidal effect could be achieved on 500 ml of Karenia mikimotoi algal solution. It can be seen that the polymer-based porous modified sponge of the present invention can be used as an adsorption carrier for algicidal bacteria to reduce the biomass of red tide algae, and can be used not only during the outbreak of red tide disasters, but also for daily prevention before the outbreak of red tide disasters, and the material has a high repetition rate.
[0046] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope covered by the present invention.
Claims
1. A polymer-based porous modified sponge, characterized in that: The polymer-based porous modified sponge is prepared by cross-linking polyvinyl alcohol and formaldehyde to form a polymer skeleton, and then adding iron salt for modification.
2. The method for preparing the polymer-based porous modified adsorption sponge according to claim 1, characterized in that: The following steps are involved: S1: Mix polyvinyl alcohol and deionized water, and stir at 95°C until completely dissolved to obtain a polyvinyl alcohol solution; S2: add an emulsifier to the polyvinyl alcohol solution of S1, stir and react at 60°C for 10 minutes, then add formaldehyde, continue to stir and react at 60°C for 20 minutes to obtain a reaction solution; S3: Add FeCl3 to the reaction solution of S2, then add hydrochloric acid, and stir the reaction at 60°C for 60 minutes to obtain a functional composite solution; S4: solidifying and drying the functional composite solution of S3, washing, and drying to obtain a polymer-based porous modified sponge.
3. The preparation method according to claim 2, characterized in that: The concentration of the polyvinyl alcohol solution is 9wt%-11wt%.
4. The preparation method according to claim 2, characterized in that: The emulsifier is Tween 80.
5. The preparation method according to claim 2, characterized in that: The final concentration of the emulsifier is 3.5wt% to 4.5wt%.
6. The preparation method according to claim 2, characterized in that: The final concentration of the formaldehyde is 3wt% to 3.4wt%.
7. The preparation method according to claim 2, characterized in that: The final concentration of the FeCl3 is 1wt%~3wt%.
8. The preparation method according to claim 2, characterized in that: The final concentration of the hydrochloric acid is 4 wt %.
9. Use of the polymer-based porous modified sponge as claimed in claim 1 in red tide prevention and control.
10. The use according to claim 9, characterized in that: The polymer-based porous modified sponge can reduce the biomass of red tide algae by immobilizing and adsorbing algae-lysing bacteria, thereby achieving the effect of preventing and controlling red tides.