Dicationic functionalized bio-based algae removal material and preparation method thereof

Abstract

The invention discloses a quaternary ammonium / quaternary phosphorus salt dication functionalized bio-based algae removal material and a preparation method thereof. The bio-based algae removal material is a dicationic functionalized bio-based material which is obtained by grafting hydrophilic linear macromolecules on the surface and modifying two acting groups of quaternary ammonium salt and quaternary phosphonium salt on the linear macromolecules at the same time, and is applied to removal of red tide algae in seawater. The bio-based algae removal material is simultaneously modified with two dication functional groups of quaternary ammonium salt and quaternary phosphonium salt, can realize electrostatic adsorption removal of red-tide algae in seawater and surface tension reduction of red-tide algae sediments, accelerates gas exchange and decomposition of the sediments and a water body, is efficient in action and environment-friendly, and can be widely applied to the field of water treatment. The method can be used for efficiently removing red tide algae such as karenia mikimotoi and quickly decomposing sediments.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bio-based materials, and particularly relates to a kind of double cation functionalized bio-based algae-removal material and its preparation method. BACKGROUND

[0002] The outbreak of red tide algae can destroy the marine ecosystem, harm aquaculture and human health, and the removal of red tide algae is of great significance to ecological protection and economic stability.

[0003] Currently, many breakthroughs have been made in the removal of red tide algae. In terms of chemistry, the pesticide Xtreme-RT based on plant components can quickly reduce the density of Karenia mikimotoi, but the cost of treatment is high for vast marine water bodies and low-density algal blooms, and the efficiency of algae removal is low. In terms of inorganic modified materials, by changing the surface properties of clay, it can be changed from negative to positive, greatly improving the flocculation efficiency with negatively charged red tide algae cells, but clay is not easy to degrade, such as large-scale use of clay in a short time, which may change the ecological environment of the seabed. In terms of biological control, scientists have isolated algicidal bacteria of the genera Bacillus, Pseudomonas and other genera from water bodies to inhibit algal growth. For example, a Japanese research team isolated the parasitic Amoebophryasp. OSK2020 strain, which had an infection rate of 97% for 6 strains of Karenia mikimotoi after 60 hours, and completely eliminated the host population after 168 hours. However, biological methods have high requirements for environmental conditions and low treatment efficiency, making it difficult to achieve rapid emergency disposal of red tide algae.

[0004] In the process of removing red tide algae, it is necessary to achieve efficient removal of algae, while also considering the degradability, environmental safety and ecological safety of the deposited substrate of the removal material. Therefore, in order to achieve the above goals, it is necessary to introduce a bio-based material with good environmental safety and compatibility as a carrier for surface modification, while also considering algae adsorption and sediment substrate modification, to construct a quaternary ammonium salt / quaternary phosphonium salt double cation functionalized bio-based algae-removal material with electrostatic adsorption removal of red tide algae and synergistic effect of biomass substrate decomposition. SUMMARY

[0005] The present application aims to provide a double cation functionalized bio-based algae-removal material with electrostatic adsorption removal of red tide algae and synergistic effect of biomass substrate decomposition, and its preparation method. The present application utilizes epoxy addition reaction to graft hydrophilic linear polymers on the surface of bio-based materials, and then modifies quaternary ammonium salt ion groups on the linear polymers, which have strong adsorption effect on negatively charged algal cell membranes, and quaternary phosphonium salt ion groups, which have strong inhibition effect on algal growth and modification effect on sediment substrates. At the same time, it also considers algae adsorption and sediment substrate surface tension reduction, accelerates gas exchange and oxidative decomposition of sediment and water body, and achieves efficient adsorption and removal of red tide algae in seawater and rapid decomposition of rice straw / algal sediment.

[0006] To achieve the above object, the application adopts the following technical solutions: A quaternary ammonium / quaternary phosphonium salt double-cation functionalized bio-based algae-removal material is prepared by grafting a hydrophilic linear polymer on the surface, and simultaneously modifying the linear polymer with quaternary ammonium salt ion groups having strong adsorption on negative charge red tide algae and quaternary phosphonium salt ion groups having strong inhibition on the growth of algae and decomposition of biomass substrates; the bio-based material can achieve electrostatic adsorption removal of red tide algae in seawater and reduction of surface tension of sediment substrates, accelerate gas exchange and decomposition of the sediment and water body, and achieve efficient adsorption removal of red tide algae in seawater and rapid decomposition of the sediment.

[0007] Further, the hydrophilic linear polymer is polyvinyl alcohol 224.

[0008] Further, the quaternary ammonium salt is a quaternary ammonium salt bonded by ring-opening reaction with 2,3-epoxypropyl trimethyl ammonium chloride.

[0009] Further, the quaternary phosphonium salt is a quaternary phosphonium salt bonded by grafting reaction with tetramethylol phosphorus sulfate.

[0010] Further, the bio-based material is rice straw.

[0011] The preparation method of the double-cation functionalized bio-based algae-removal material is to mix and react the crushed rice straw with an alkali solution at 60 0 C, then mix and add polyvinyl alcohol macromolecules to the crushed rice straw and the alkali solution by ring-opening addition reaction of the epoxy, and continue to react with the epoxy, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethylol phosphorus sulfate, to simultaneously modify the quaternary ammonium salt and the quaternary phosphonium salt by epoxy ring-opening addition reaction, and prepare the double-cation functionalized bio-based algae-removal material.

[0012] Further, the preparation method specifically includes the following steps: (1) mix and react the crushed rice straw (not more than 80 mesh) with an alkali solution at 60 0 C, and stir at 500 rpm for 2h to form a reaction liquid A; (2) add the epoxy chloropropane and the polyvinyl alcohol solution to the reaction liquid A, and stir at 500 rpm at 60 0 C for 12h to obtain product B by filtration; (3) disperse product B in an alkali solution by ultrasonic dispersion, and add the epoxy chloropropane, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethylol phosphorus sulfate to perform epoxy ring-opening addition reaction at 60 0C stirring at 500 rpm for 12 h while modifying the quaternary ammonium / phosphonium salt, to obtain the final product, which is washed with water several times to obtain the dicationic functionalized bio-based algae-removal material.

[0013] Further, the mass ratio of the rice straw, polyvinyl alcohol, epichlorohydrin, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethylammonium phosphate used is 6:3:42.5:72:192.

[0014] Further, the alkali solution in steps (1) and (3) is a 2% sodium hydroxide solution.

[0015] The dicationic functionalized bio-based algae-removal material is applied to remove red tide algae in seawater.

[0016] Further, the red tide algae include Karenia mikimotoi, Peridinium robustum and Prorocentrum donghaiense.

[0017] The present application has the following advantages: 1. The present application uses an epoxy addition reaction to graft a hydrophilic linear polymer onto the surface of a bio-based material, and then simultaneously modifies the linear polymer with quaternary ammonium salt ion groups and quaternary phosphonium salt ion groups which have a strong adsorption effect on the negatively charged cell membrane of algae. The positively charged quaternary ammonium salt ion groups and quaternary phosphonium salt ion groups in the molecule are easily electrostatically adsorbed to the negatively charged cell membrane of algae, thereby removing red tide algae by electrostatic adsorption. At the same time, the strong electrostatic adsorption can destroy the integrity of the cell membrane of algae and improve the permeability of the membrane, resulting in the leakage of soluble proteins and other substances in the algae cells, thereby killing red tide algae and achieving efficient algae removal.

[0018] 2. The present application simultaneously modifies and bonds tetramethylammonium phosphate to the linear polymer, which not only adsorbs algae but also modifies the sediment substrate, has surfactant properties, breaks the surface tension of the sediment, accelerates the gas exchange between the sediment and the water body, increases the dissolved oxygen content of the bottom water body, accelerates the oxidative decomposition of the sediment, and achieves rapid decomposition of the red tide algae sediment.

[0019] Compared with traditional modified flocculants, the present method simultaneously introduces quaternary ammonium salt ion groups and quaternary phosphonium salt ion groups, which not only destroys the integrity of the cell membrane of algae by electrostatic adsorption to remove red tide algae, but also decomposes active hydroxymethyl under the assistance of microorganisms in the sediment through tetramethylammonium phosphate, strengthens the surface activity of the sediment, breaks the surface tension of the sediment, accelerates the gas exchange between the sediment and the water body, accelerates the oxidative decomposition of the sediment, and achieves rapid decomposition of the red tide algae sediment, thereby avoiding the problem of the ecological environment of the seabed being affected due to the difficulty in decomposition of the substrate formed by conventional flocculants. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1A schematic diagram for preparation of a biobased dual-cationic functionalized algae-removal material.

[0021] Figure 2 Microscope images of adsorption of algae by a quaternary ammonium / quaternary phosphonium salt dual-cationic functionalized biobased algae-removal material.

[0022] a-e are, in order, Peridinium robustum, Protoperidinium minutum, Karenia mikimotoi, Protoperidinium jeorgii, and Protoperidinium oceanicum DETAILED DESCRIPTION

[0023] A biobased dual-cationic functionalized algae-removal material, the preparation of which comprises the following steps: (1) mixing crushed rice straw (not more than 80 mesh) with a 2% sodium hydroxide solution at 60 0 C, stirring at 500 rpm for 2 h to form a reaction solution A; (2) adding epichlorohydrin and a polyvinyl alcohol solution to the reaction solution A, stirring at 500 rpm for 12 h at 60 0 C to obtain product B after filtration; (3) dispersing product B in a 2% sodium hydroxide solution by ultrasonic dispersion, adding epichlorohydrin, 2,3-epoxypropyltrimethylammonium chloride, and tetrahydroxymethyl phosphonium sulfate to perform an epoxide ring-opening addition reaction, stirring at 500 rpm for 12 h at 60 0 C while modifying the quaternary ammonium / quaternary phosphonium salt to obtain the final product, washing the product with deionized water (H2O) three times to obtain the target product.

[0024] The mass ratio of the rice straw, polyvinyl alcohol, epichlorohydrin, 2,3-epoxypropyltrimethylammonium chloride, and tetrahydroxymethyl phosphonium sulfate used is 6:3:42.5:72:192.

[0025] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in conjunction with specific embodiments, but the present application is not limited thereto.

[0026] Unless otherwise specified, the various raw materials, reagents, instruments, and equipment used in the present application can be purchased on the market or can be prepared by existing methods.

[0027] Example 1 This example provides a preparation of a biobased dual-cationic functionalized algae-removal material, which comprises grafting polyvinyl alcohol by reacting rice straw and epichlorohydrin, polyvinyl alcohol solution, and bonding 2,3-epoxypropyltrimethylammonium chloride and tetrahydroxymethyl phosphonium sulfate on the polyvinyl alcohol by one-pot method to form a biobased algae-removal material of dual-cationic functionalized modified rice straw fiber with simultaneous modification of quaternary ammonium / quaternary phosphonium salt. The preparation process is as follows: Figure 1The specific steps are as follows: (1) Hydroxyl activation of rice straw: In a 500 mL round-bottom flask, 6 g of crushed rice straw RS (not more than 80 mesh) was mixed with 150 mL of a 2% sodium hydroxide (NaOH) solution, 60 0 C, and stirred at 500 rpm for 2 h to form reaction liquid A.

[0028] (2) Surface grafting of polyvinyl alcohol: 3 g of polyvinyl alcohol PVA 224 was mixed with 150 mL of a 2% NaOH solution, 80 0 C, and heated and stirred until the PVA was completely dissolved, and then transferred to a 250 mL constant-pressure funnel; in a 500 mL round-bottom flask, reaction liquid A and 36 mL of epichlorohydrin ECH (density 1.18 g / mL, mass 42.5 g) were added, 60 0 C, and the PVA in the constant-pressure funnel was slowly added dropwise (1 drop every 2-3 seconds, and the dripping was completed in 1-2 h), and the reaction was carried out for 12 h, and then filtered; the product was washed twice with water, and then soaked in ethanol, 60 0 C, and dried to obtain the product RS-PVA.

[0029] (3) Quaternary ammonium / quaternary phosphonium salt double-cation functionalization modification of rice straw: The above product RS-PVA was ultrasonically dispersed in 150 mL of a 2% sodium hydroxide solution, and 36 mL of epichlorohydrin ECH (mass 42.5 g), 72 g of 2,3-epoxypropyltrimethylammonium chloride, and 192 g of tetramethylol phosphonium sulfate were added, 60 0 C, and the reaction was carried out for 12 h under 500 rpm stirring to perform an epoxy ring-opening addition reaction, and quaternary ammonium / quaternary phosphonium salt was simultaneously bonded on the RS-PVA; the product was washed three times with deionized water (H2O) to obtain the target product RS-PVA-EPTAC / THPS.

[0030] Example 2 In this example, the performance of the quaternary ammonium / quaternary phosphonium salt double-cation functionalized bio-based algae-removal material prepared in Example 1 was characterized.

[0031] RS-PVA-EPTAC / THPS was used to adsorb the red tide algae in the culture solution. 50 mg of RS-PVA-EPTAC / THPS was dispersed in 100 mL of seawater, and stirred at 250 rpm for 30 min, and then left for 10 min. A biological microscope (EX21) (magnification: ocular 10x, objective 10x) was used to observe the adsorption performance of the quaternary ammonium salt and quaternary phosphonium salt modified straw on the red tide algae. The results showed that RS-PVA-EPTAC / THPS had good adsorption effect on the red tide algae, and the number of red tide algae in the upper liquid after adsorption of RS-PVA-EPTAC / THPS was significantly removed, with a removal rate of 94.1%-82.6% (Table 1). The above results showed that RS-PVA-EPTAC / THPS showed good adsorption effect on the red tide algae.

[0032] Table 1 Removal efficiency of RS-PVA-EPTAC / THPS on main red tide algae

[0033] Example 3 In this example, the performance of the quaternary ammonium salt / quaternary phosphonium salt double-cation functionalized bio-based algae-removal material prepared in Example 1 was characterized.

[0034] RS-PVA-EPTAC / THPS was used to adsorb the red tide algae cultured in a sea cucumber breeding pond (enclosure, 1 m long x 1 m wide x 0.8 m deep). The changes in the indicators of the bottom mud before and after algae removal were observed. 400 g of RS-PVA-EPTAC / THPS was dispersed in seawater (0.8 m 3 ) with a bottom mud thickness of not more than 5 cm. The water temperature was controlled at 20°C, the salinity was 31‰-32‰, the pH was 7.8-8.2, continuous trace oxygenation was performed, the water flow rate was 1-2 cm / s, and the test period was 30 days. The control group was the test with the addition of ordinary flocculants. After the test, the surface 0-2 cm mud samples were collected, and the COD, ammonia nitrogen and sulfide contents were determined by potassium dichromate method, indigo blue method and iodometric method, respectively. Table 2 shows the improvement activity of RS-PVA-EPTAC / THPS on different indicators in the substrate. The results showed that the prepared RS-PVA-EPTAC / THPS contained a bottom material modifier, and the contents of ammonia nitrogen, COD and sulfide in the bottom mud showed a downward trend.

[0035] Table 2 RS-PVA-EPTAC / THPS bottom material improvement effect

[0036] As can be seen from the table, the three indexes of the control group and each experimental group all show an upward trend, but the relative change rate of each index of the test group relative to the control group is negative when the RS-PVA-EPTAC / THPS containing a substrate modifier is applied, indicating that the RS-PVA-EPTAC / THPS applied in the test group has a good substrate modification effect. This is because THPS has strong polarization, the surrounding positive charge increases, and it is easier to produce electrostatic adsorption with the negatively charged substances in the sediment. The THPS group has a strong complexation effect. Studies have found that the THPS group can adsorb negatively charged substances in the sediment, thereby increasing the oxidation-reduction potential of the surface environment of the sediment, and can effectively inhibit the growth of sulfur-reducing bacteria in the water environment, which is conducive to its application in actual production.

[0037] According to examples 1-3, the biobased algal-removal material containing quaternary ammonium / quaternary phosphonium salt double-cation provided by the application is simple and feasible to prepare, has good effects of adsorbing red tide algae and modifying substrates.

[0038] The above only describes the preferred embodiments of the application, and any changes and modifications made within the scope of the application should be included in the scope of the application.

Claims

1. A dicationic functionalized bio-based algaecidal material, characterized in that, The bio-based algae-removal material is a bio-based material with surface-grafted hydrophilic linear polymers, and simultaneously modified with two types of action groups, quaternary ammonium salt and quaternary phosphonium salt, which is a double-cationic functionalized bio-based material; the bio-based material can achieve electrostatic adsorption removal of red tide algae in seawater and rapid oxidation and decomposition of red tide algae sediments.

2. The dicationic functionalized bio-based algaecidal material of claim 1, wherein, The hydrophilic linear polymer is polyvinyl alcohol 224.

3. The dicationic functionalized bio-based algaecidal material of claim 1, wherein, The quaternary ammonium salt is a quaternary ammonium salt bonded through ring-opening reaction with 2,3-epoxypropyl trimethyl ammonium chloride.

4. The dicationic functionalized bio-based algaecidal material of claim 1, wherein, The quaternary phosphonium salt is a quaternary phosphonium salt bonded through grafting reaction with tetramethylol phosphorus sulfate.

5. The dicationic functionalized bio-based algaecidal material of claim 1, wherein, The bio-based material is rice straw.

6. A method of preparing a dicationic functionalized bio-based algaecidal material according to claim 1, characterized in that, In 60 0 The pulverized rice straw is mixed with an alkali solution to react first, then the product is mixed with epichlorohydrin and polyvinyl alcohol to add polyvinyl alcohol polymer through ring-opening addition reaction, and then the product is continuously reacted with epichlorohydrin, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethyl phosphonium sulfate to modify quaternary ammonium salt / quaternary phosphonium salt through ring-opening addition reaction of epoxy, thereby preparing a bio-based algae-removal material with double cationic functions.

7. The preparation method of the dual-cationic functionalized bio-based algaecide material according to claim 6, characterized in that, The method comprises the following steps: (1) In 60 0 C, mixed the crushed rice straw (not more than 80 mesh) with alkali solution, stirred at 500 rpm for 2 h to form reaction liquid A. (2) Add epichlorohydrin and polyvinyl alcohol solution into reaction liquid A, 60 0 Cstirring under 500 rpm for 12 h, filter to obtain product B; (3) The product B is ultrasonically dispersed in an alkali solution, and an epoxy chloropropane, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethylol phosphonium sulfate are added to perform an epoxy ring-opening addition reaction, 60 0 C The reaction is stirred at 500 rpm for 12 h, while the quaternary ammonium / quaternary phosphonium salt is modified, to obtain the final product. The product is washed with water multiple times to obtain the dicationic functionalized bio-based algaecidal material.

8. The method of claim 6 or 7, wherein the biobased dicationic functionalized algaecidal material is prepared by the process comprising the steps of: The mass ratio of the used rice straw, polyvinyl alcohol, epichlorohydrin, 2,3-epoxypropyl trimethyl ammonium chloride and tetramethylol phosphorus sulfate is 6:3:42.5:72:

192.

9. The preparation method of the dual-cationic functionalized bio-based algaecide material according to claim 7, characterized in that, The alkali solution in steps (1) and (3) is a 2% sodium hydroxide solution.

10. Use of the double-cationic functionalized bio-based algae-removal material according to claim 1 in removal of red tide algae in seawater.

11. The dicationic functionalized bio-based algaecidal material according to claims 1 and 10, characterized in that, The red tide algae include Karenia mikimotoi, Prorocentrum concavum, Prorocentrum donghaiense, Prorocentrum micans and Prorocentrum minimum.

Images