CN115650791A - Multifunctional soil slow-release agent and preparation method thereof - Google Patents
Multifunctional soil slow-release agent and preparation method thereof Download PDFInfo
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- CN115650791A CN115650791A CN202211273266.4A CN202211273266A CN115650791A CN 115650791 A CN115650791 A CN 115650791A CN 202211273266 A CN202211273266 A CN 202211273266A CN 115650791 A CN115650791 A CN 115650791A
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- 239000002689 soil Substances 0.000 title claims abstract description 76
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
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- 239000003431 cross linking reagent Substances 0.000 claims abstract description 10
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- 150000004676 glycans Chemical class 0.000 claims abstract 15
- 238000013268 sustained release Methods 0.000 claims description 25
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- 239000004202 carbamide Substances 0.000 claims description 18
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 11
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 11
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 claims description 11
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 claims description 10
- 229920001213 Polysorbate 20 Polymers 0.000 claims description 10
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 claims description 10
- 239000000256 polyoxyethylene sorbitan monolaurate Substances 0.000 claims description 10
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- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims description 6
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- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 6
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- 125000002843 carboxylic acid group Chemical group 0.000 claims description 6
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- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 6
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 claims description 5
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 claims description 5
- 229920000053 polysorbate 80 Polymers 0.000 claims description 5
- LQZZUXJYWNFBMV-UHFFFAOYSA-N dodecan-1-ol Chemical compound CCCCCCCCCCCCO LQZZUXJYWNFBMV-UHFFFAOYSA-N 0.000 claims description 4
- 235000010643 Leucaena leucocephala Nutrition 0.000 claims description 2
- 238000000034 method Methods 0.000 claims 8
- 241000220479 Acacia Species 0.000 claims 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 24
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 11
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- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 5
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- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 3
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- ZPWVASYFFYYZEW-UHFFFAOYSA-L dipotassium hydrogen phosphate Chemical compound [K+].[K+].OP([O-])([O-])=O ZPWVASYFFYYZEW-UHFFFAOYSA-L 0.000 description 1
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Images
Abstract
The invention provides a multifunctional soil slow-release agent and a preparation method thereof, belonging to the technical field of high polymer materials. The polysaccharide is mixed with a phosphate buffer solution to obtain a polysaccharide solution; sequentially adding an activating agent, a cross-linking agent and a functional additive into the polysaccharide solution, mixing and standing to form gel to obtain polysaccharide hydrogel; and (4) freeze-drying the polysaccharide hydrogel to obtain the multifunctional slow-release agent for soil. The multifunctional soil slow-release agent is prepared by a sol-gel method and a freeze drying technology. The water absorption rate of the multifunctional soil slow release agent can reach above 730g/g, and the multifunctional soil slow release agent can still be applied to arid soil. The slow release agent also has the effect of increasing fertilizer, obviously improves the effective nitrogen content in soil, provides nutrient components for crops, and is a multifunctional soil slow release agent. The preparation method of the invention has simple operation, reaction condition and temperature, does not generate toxic and harmful substances, is environment-friendly and degradable.
Description
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a multifunctional soil slow-release agent and a preparation method thereof.
Background
Most of the existing water-absorbing slow-release materials are acrylic acid and acrylamide products, and because acrylic acid and acrylamide have more water-absorbing groups, a synthetic polymer obtained by polymerization of the acrylic acid and the acrylamide products is a polymer material with extremely strong water-absorbing capacity. However, the high polymer material has high cost and low water absorption efficiency under high-concentration electrolyte, and the material is not degradable, thereby bringing a large amount of white pollution to the ecological environment. The natural polysaccharide is a polysaccharide formed by dehydrating and polymerizing monosaccharides, is an important component of a biopolymer substance, is widely present in plants, animals and microorganisms, and is in a variety of varieties, and the most common natural polysaccharides are cellulose, chitosan, alginic acid, starch and the like. The natural polysaccharide generally contains rich active groups, such as hydroxyl, amino, carboxyl and the like, and has better water absorption performance.
In polysaccharide water-absorbing slow-release materials researched in the prior art, sodium carboxymethyl cellulose is mostly used as a raw material, and the sodium carboxymethyl cellulose is activated and cross-linked to obtain a cross-linked water-absorbing slow-release material. However, the material can be degraded in soil slowly, the water retention effect is not enough to meet the requirements of crops, and the soil impoverishment condition cannot be improved. Therefore, how to improve the prior technical scheme to obtain a sustained-release agent which has high water absorption rate, is biodegradable and can be slowly released is a technical problem to be solved at present.
Disclosure of Invention
The invention aims to provide a multifunctional soil sustained-release agent and a preparation method thereof, and aims to solve the technical problems that a sustained-release material in the prior art is not degradable, has poor water absorption performance and cannot effectively provide nutrient components required by plants.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a multifunctional soil sustained-release agent, which comprises the following steps:
1) Mixing polysaccharide with phosphate buffer solution to obtain polysaccharide solution;
2) Sequentially adding an activating agent, a cross-linking agent and a functional additive into the polysaccharide solution, mixing and standing to form gel to obtain polysaccharide hydrogel;
3) And (4) freeze-drying the polysaccharide hydrogel to obtain the multifunctional slow-release agent for soil.
Further, the polysaccharide comprises one or more of sodium alginate, acacia, carboxymethyl chitosan and sodium carboxymethyl cellulose.
Further, the phosphate buffer solution is obtained by mixing a potassium dihydrogen phosphate solution and a disodium hydrogen phosphate solution according to a certain proportion, wherein the concentration of the potassium dihydrogen phosphate solution is 0.05-0.08 mol/L, the concentration of the disodium hydrogen phosphate solution is 0.05-0.08 mol/L, and the pH value of the phosphate buffer solution is 5.0-6.8.
Further, the mass volume ratio of the polysaccharide to the phosphate buffer solution is 2.0-8.0 g:100mL.
Further, the activator comprises one or more of tween 20, tween 40 and tween 80; the molar ratio of carboxylic acid groups to activating agent in the polysaccharide is 1:1.5 to 2.0.
Further, the cross-linking agent comprises urea; the molar ratio of carboxylic acid groups to cross-linking agent in the polysaccharide is 1:0.5 to 1.2.
Further, the functional additive comprises one or more of p-phenylenediamine, linoleic acid diethanolamide and lauryl alcohol diethanolamide; the addition amount of the functional additive is 1-3 wt% of the mass of the polysaccharide solution.
Further, the standing time is 3-5 h.
Furthermore, the temperature of the freeze drying is-70 to-50 ℃, the pressure of the freeze drying is 1 to 10Pa, and the time of the freeze drying is 20 to 40 hours.
The invention also provides a multifunctional soil slow release agent.
The invention has the beneficial effects that:
the multifunctional soil slow-release agent is prepared by a sol-gel method and a freeze drying technology. The water absorption rate of the multifunctional soil slow release agent can reach above 730g/g, and the multifunctional soil slow release agent can still be applied to arid soil. The slow release agent also has the effect of increasing fertilizer, obviously improves the effective nitrogen content in soil, provides nutrient components for crops, and is a multifunctional soil slow release agent. The preparation method of the invention has simple operation, reaction condition and temperature, does not generate toxic and harmful substances, is environment-friendly and degradable.
Drawings
FIG. 1 is a test chart of water absorption properties of the multi-functional soil release agent obtained in examples 1 to 6 of the present invention and comparative examples;
FIG. 2 is a degradation test chart of the multifunctional soil release agent obtained in example 1 of the present invention;
FIG. 3 is a graph showing the change in the effective nitrogen content in the soil after tomatoes are planted according to example 1 of the present invention.
Detailed Description
The invention provides a preparation method of a multifunctional soil slow release agent, which comprises the following steps:
1) Mixing polysaccharide with phosphate buffer solution to obtain polysaccharide solution;
2) Sequentially adding an activating agent, a cross-linking agent and a functional additive into the polysaccharide solution, mixing and standing to form gel to obtain polysaccharide hydrogel;
3) And (4) freeze-drying the polysaccharide hydrogel to obtain the multifunctional slow-release agent for soil.
In the invention, the polysaccharide comprises one or more of sodium alginate, arabic gum, carboxymethyl chitosan and sodium carboxymethyl cellulose, and preferably sodium alginate and/or Arabic gum.
In the invention, the phosphate buffer solution is obtained by mixing a potassium dihydrogen phosphate solution and a disodium hydrogen phosphate solution according to a certain proportion, and the concentration of the potassium dihydrogen phosphate solution is 0.05-0.08 mol/L, preferably 0.06-0.07 mol/L, and more preferably 0.065mol/L.
In the present invention, the concentration of the disodium hydrogen phosphate solution is 0.05 to 0.08mol/L, preferably 0.06 to 0.07mol/L, and more preferably 0.065mol/L; the pH of the phosphate buffer is 5.0 to 6.8, preferably 5.2 to 6.0, and more preferably 5.6 to 6.0.
In the invention, the mass volume ratio of the polysaccharide to the phosphate buffer solution is 2.0-8.0 g:100mL, preferably 3.0 to 7.0g:100mL, more preferably 4.0 to 7.0g:100mL.
In the present invention, the activator comprises one or more of tween 20, tween 40 and tween 80, preferably tween 20.
In the present invention, the molar ratio of carboxylic acid groups to activating agent in the polysaccharide is 1:1.5 to 2.0, preferably 1:1.6 to 1.8, more preferably 1:1.7.
in the present invention, the cross-linking agent comprises urea, preferably urea.
In the present invention, the molar ratio of carboxylic acid groups to cross-linking agent in the polysaccharide is 1:0.5 to 1.2, preferably 1:0.6 to 1.0, more preferably 1:0.7 to 1.8.
In the invention, the functional additive comprises one or more of p-phenylenediamine, linoleic acid diethanolamide and lauryl alcohol diethanolamide, and p-phenylenediamine is preferred.
In the present invention, the addition amount of the functional additive is 1 to 3wt%, preferably 1.5 to 2.5wt%, and more preferably 2wt% of the polysaccharide solution.
In the present invention, the standing time is 3 to 5 hours, preferably 4 hours.
In the invention, the temperature of the freeze drying is-70 to-50 ℃, preferably-65 to-55 ℃, and more preferably-60 ℃; the pressure of freeze drying is 1-10 Pa, preferably 2-8 Pa, and more preferably 3-6 Pa; the freeze-drying time is 20 to 40 hours, preferably 22 to 38 hours, and more preferably 25 to 30 hours.
The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
Example 1
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.065mol/L and a disodium hydrogen phosphate solution with the concentration of 0.065mol/L according to a certain volume ratio to obtain 100 mLphosphate buffer solution with the pH value of 6.5; adding 2.0g of sodium alginate into the phosphate buffer solution, and uniformly mixing to obtain the polysaccharide solution.
Preparing a multifunctional soil sustained-release agent:
sequentially adding Tween 20, urea and p-phenylenediamine into the polysaccharide solution, continuously stirring for 2h, uniformly mixing, and standing for 3h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-60 ℃ under 5pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 20 and urea in the polysaccharide is 1:1.5:0.8, wherein the addition amount of the p-phenylenediamine is 2wt percent of the mass of the polysaccharide solution.
Example 2
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.075mol/L and a disodium hydrogen phosphate solution with the concentration of 0.075mol/L according to a certain volume ratio to obtain a phosphate buffer solution with the pH value of 100 mL6.3; adding 2.5g of carboxymethyl chitosan into a phosphate buffer solution, and uniformly mixing to obtain a polysaccharide solution.
Preparing a multifunctional soil slow release agent:
sequentially adding tween 20, urea and linoleic acid diethanolamide into the polysaccharide solution, continuously stirring for 3h, uniformly mixing, and standing for 5h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-70 ℃ and 5pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 20 and urea in the polysaccharide is 1:1.65:0.7, the addition amount of linoleic acid diethanolamide is 1wt% of the polysaccharide solution.
Example 3
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.05mol/L and a disodium hydrogen phosphate solution with the concentration of 0.055mol/L according to a certain volume ratio to obtain 100 mLphosphate buffer solution with the pH value of 6.5; adding 3.5g of sodium carboxymethylcellulose into the phosphate buffer solution, and uniformly mixing to obtain the polysaccharide solution.
Preparing a multifunctional soil sustained-release agent:
sequentially adding tween 40, urea and laurinol diethanolamide into the polysaccharide solution, continuously stirring for 3h, uniformly mixing, and standing for 5h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-50 ℃ under 10pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 40 and urea in the polysaccharide is 1:2.0:0.6, the addition amount of the lauryl alcohol diethanolamide is 2wt percent of the mass of the polysaccharide solution.
Example 4
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.05mol/L and a disodium hydrogen phosphate solution with the concentration of 0.055mol/L according to a certain volume ratio to obtain a phosphate buffer solution with the pH value of 100 mL6.0; adding 4.0g of Arabic gum into the phosphate buffer solution, and uniformly mixing to obtain a polysaccharide solution.
Preparing a multifunctional soil sustained-release agent:
sequentially adding tween 80, urea and p-phenylenediamine into the polysaccharide solution, continuously stirring for 3h, uniformly mixing, and standing for 5h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-50 ℃ under 10pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 80 and urea in the polysaccharide is 1:1.8:0.75, and the addition amount of the p-phenylenediamine is 3wt percent of the mass of the polysaccharide solution.
Example 5
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.085mol/L and a dipotassium hydrogen phosphate solution with the concentration of 0.085mol/L according to a certain volume ratio to obtain 100 mLphosphate buffer solution with the pH value of 5.5; adding 5.0g of sodium alginate into phosphate buffer solution, and mixing uniformly to obtain polysaccharide solution.
Preparing a multifunctional soil sustained-release agent:
sequentially adding Tween 40, urea and linoleic acid diethanolamide into the polysaccharide solution, continuously stirring for 3h, uniformly mixing, and standing for 5h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-50 ℃ under 10pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 40 and urea in the polysaccharide is 1:1.85:1.2, the addition amount of the linoleic acid diethanolamide is 2wt percent of the mass of the polysaccharide solution.
Example 6
Preparation of polysaccharide solution:
uniformly mixing a potassium dihydrogen phosphate solution with the concentration of 0.085mol/L and a disodium hydrogen phosphate solution with the concentration of 0.085mol/L according to a certain volume ratio to obtain 100 mLphosphate buffer solution with the pH value of 5.8; adding 7.0g of carboxymethyl chitosan into a phosphate buffer solution, and uniformly mixing to obtain a polysaccharide solution.
Preparing a multifunctional soil sustained-release agent:
sequentially adding Tween 40, urea and p-phenylenediamine into the polysaccharide solution, continuously stirring for 3h, uniformly mixing, and standing for 5h to obtain polysaccharide hydrogel; and (3) putting the polysaccharide hydrogel into a freeze dryer, and drying for 30 hours at-50 ℃ under 10pa to obtain the multifunctional soil sustained-release agent. Wherein, the molar ratio of carboxyl group, tween 40 and urea in the polysaccharide is 1:1.85:1.2, the addition amount of the p-phenylenediamine is 1wt percent of the mass of the polysaccharide solution.
Comparative example
The difference from the embodiment 1 is that the sustained release agent is obtained by directly mixing acrylic acid, urea and tween 20 without adding a functional additive, wherein the molar ratio of the acrylic acid to the urea to the tween 20 is 1:0.8:1.5.
test example
The slow release agents for multifunctional soil obtained in examples 1 to 6 and the slow release agents obtained in comparative examples are subjected to performance tests, after the slow release agents obtained in examples 1 to 6 and comparative examples are put into an aqueous solution to absorb water for 8 hours, the volume of the slow release agent material is increased by several times, but the material is not dissolved or damaged, so that the slow release agent for multifunctional soil obtained by the invention has excellent water absorption performance, and the test result is shown in figure 1.
The multifunctional soil sustained release agent obtained in example 1 was subjected to a degradation test, and the multifunctional soil sustained release agent was placed in a soil environment to test the degradation rate thereof within 6 weeks, and the results are shown in fig. 2. As can be seen from fig. 2, the degradation rate of the sustained release agent obtained in example 1 of the present invention in the first week can reach 32.0%, the degradation rate in the second week can reach 58.5%, the degradation rate in the third week can reach 70.4%, the degradation rate in the fourth week can reach 77.9%, the degradation rate in the fifth week can reach 85.5%, and the degradation rate in the sixth week can reach 90.4%. As can be seen, the sustained-release agent can be basically and completely degraded in the soil after 6 to 7 weeks at most along with the lapse of time, does not pollute the soil environment, and has high biodegradation rate.
The influence of the slow release agent on the effective N content in soil is tested as follows:
1. planting tomatoes
Dividing farmland soil into three equal parts, respectively designing into an original soil sample group, a sample group (containing the slow release agent of the embodiment 1) and a blank group (not containing the slow release agent of the embodiment), respectively planting three tomato seedlings in three experimental groups, testing the nitrogen content in each experimental group before planting, testing once after 15 days, and testing once after one month. The results of the change of the effective nitrogen content in the three experimental groups are shown in fig. 3, and it can be seen from fig. 3 that the addition of the slow release agent of the invention can significantly increase the effective nitrogen content in the soil and provide more fertilizer for crops.
2. Planting sunflower
As described above, three experimental groups were designed, sunflower seedlings were planted in the three experimental groups, and the change rate of the effective nitrogen content in the experimental group after one month was measured, and the results are shown in table 1 below.
TABLE 1 change in nitrogen content in soil 1 month after sunflower planting in three experimental groups
| Experimental group | Effective nitrogen content mg/Kg | Variable multiplying power |
| Raw soil sample group | 22.04 | 1 |
| Blank group | 10.45 | 0.47 |
| Sample set | 60.11 | 2.72 |
As can be seen from the above table 1, the addition of the sustained release agent of the present invention can not only increase the effective nitrogen content in the soil, but also keep the change rate of the nitrogen content stable after the crops are planted, and the sustained release agent can not only play a role in water absorption and retention, but also improve the soil fertility, provide nutrient components for the crops, and increase the crop yield.
From the above embodiments, the invention provides a multifunctional soil sustained-release agent and a preparation method thereof. The multifunctional soil slow-release agent is prepared by a sol-gel method and a freeze drying technology. The water absorption rate of the multifunctional soil slow release agent can reach above 730g/g, and the multifunctional soil slow release agent can still be applied to arid soil. The multifunctional soil slow release agent has good degradation performance in the soil environment, and cannot pollute the soil. The slow release agent prepared by the invention also has the effect of increasing fertilizer, obviously improves the effective nitrogen content in soil, provides nutrient components for crops, and is a multifunctional soil slow release agent. The preparation method of the invention has simple operation, reaction condition and temperature, does not generate toxic and harmful substances, and is environment-friendly.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The preparation method of the multifunctional slow release agent for soil is characterized by comprising the following steps of:
1) Mixing polysaccharide with phosphate buffer solution to obtain polysaccharide solution;
2) Sequentially adding an activating agent, a cross-linking agent and a functional additive into the polysaccharide solution, mixing and standing to form gel to obtain polysaccharide hydrogel;
3) And (4) freeze-drying the polysaccharide hydrogel to obtain the multifunctional slow-release agent for soil.
2. The method for preparing the slow-release agent for multifunctional soil according to claim 1, wherein the polysaccharide comprises one or more of sodium alginate, acacia, carboxymethyl chitosan and sodium carboxymethyl cellulose.
3. The method for preparing a sustained-release agent for multipurpose soil according to claim 2, wherein the phosphate buffer solution is obtained by mixing a potassium dihydrogen phosphate solution and a disodium hydrogen phosphate solution in a ratio of 0.05 to 0.08mol/L in concentration, and 5.0 to 6.8 in pH.
4. The method for preparing the slow-release agent for multifunctional soil according to any one of claims 1 to 3, wherein the mass volume ratio of the polysaccharide to the phosphate buffer solution is 2.0 to 8.0g:100mL.
5. The method for preparing the slow-release agent for multifunctional soil according to claim 4, wherein the activating agent comprises one or more of Tween 20, tween 40 and Tween 80; the molar ratio of carboxylic acid groups to activating agent in the polysaccharide is 1:1.5 to 2.0.
6. The method for preparing a slow-release agent for multipurpose soil according to claim 2, 3 or 5, wherein the cross-linking agent comprises urea; the molar ratio of carboxylic acid groups to cross-linking agent in the polysaccharide is 1:0.5 to 1.2.
7. The method for preparing the slow-release agent for the multifunctional soil according to claim 6, wherein the functional additive comprises one or more of p-phenylenediamine, linoleic acid diethanolamide and lauryl alcohol diethanolamide; the addition amount of the functional additive is 1-3 wt% of the mass of the polysaccharide solution.
8. The method for preparing a slow-release agent for multifunctional soil according to claim 5 or 7, wherein the standing time is 3 to 5 hours.
9. The method for preparing the slow-release agent for the multifunctional soil according to claim 8, wherein the freeze-drying temperature is-70 to-50 ℃, the freeze-drying pressure is 1 to 10Pa, and the freeze-drying time is 20 to 40 hours.
10. The sustained release agent for multifunctional soil obtained by the preparation method of any one of claims 1 to 9.
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| CN106861565A (en) * | 2017-03-15 | 2017-06-20 | 首都师范大学 | A kind of preparation method of the high intensity hydrogel with fluorescence property |
| CN111378201A (en) * | 2020-05-13 | 2020-07-07 | 海南大学 | Preparation method of environment-friendly high-water-absorption water-retention material |
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| CN102617249A (en) * | 2012-03-31 | 2012-08-01 | 山东喜丰田生态肥业有限公司 | Novel polysaccharide gel water retaining and slow release fertilizer |
| CN106861565A (en) * | 2017-03-15 | 2017-06-20 | 首都师范大学 | A kind of preparation method of the high intensity hydrogel with fluorescence property |
| CN111378201A (en) * | 2020-05-13 | 2020-07-07 | 海南大学 | Preparation method of environment-friendly high-water-absorption water-retention material |
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