Non-ionic high-molecular polymer and application thereof in saline-alkali soil improvement

Abstract

The invention discloses a nonionic high-molecular polymer and application thereof in saline-alkali soil improvement, and relates to the technical field of soil improvement. The preparation method of the non-ionic high-molecular polymer comprises the following steps: mixing water, acrylamide, fatty alcohol-polyoxyethylene ether and siloxane, adjusting the temperature to 20-35 DEG C, adding the redox initiation composition, carrying out polymerization reaction for 2-5 hours, heating to 50-75 DEG C, carrying out heat preservation for 0.5-2 hours, and drying the product to obtain the non-ionic high-molecular polymer. Specific monomers are copolymerized according to a certain proportion to obtain the nonionic high-molecular polymer, and the obtained nonionic polymer has remarkable salt and alkali reducing effects when being applied to saline-alkali soil.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a non-ionic high molecular polymer and application thereof in improving saline-alkali land. Background Art

[0002] The essence of the formation of saline-alkali land is mainly the horizontal and vertical redistribution of various soluble salts on the ground, so that the salt gradually accumulates on the soil surface. The improvement measures of saline-alkali land mainly include: water conservancy improvement, chemical improvement, biological improvement and agricultural improvement.

[0003] Water conservancy improvement measures use drip irrigation, flood irrigation, drainage, leaching and other methods to wash and drain salt from saline-alkali land, thereby reducing the salt content in the soil surface and creating an environment conducive to crop growth. The disadvantage is that the project is relatively complex. Agricultural improvement measures are mainly based on tillage, including deep plowing and loosening, land leveling, soil replacement, terrain elevation, micro-area soil improvement, surface covering and other measures to improve the soil and create suitable growth conditions for crops. Biological improvement is the screening or cultivation of salt-tolerant plants, microorganisms, and animals, relying on the interaction between plants, microorganisms and animals and soil salt to reduce the salt content of the soil. This method takes a long time to take effect and is difficult to meet the needs of improvement in a short period of time. Chemical improvement measures refer to the process of improving saline-alkali land by applying soil conditioners and other substances to saline-alkali land. It usually takes a fast effect and is simple to operate.

[0004] At present, there have been some studies on using polymers to improve soil. For example, Chinese patent CN117106457A discloses a high-salt and high-alkali soil conditioner and its preparation method and application. The high-salt and high-alkali soil conditioner includes component A solution; component A solution includes the following components by weight: 2565 parts of shale, 15-30 parts of sepiolite, 1020 parts of octylphenol polyoxyethylene ether, and 80200 parts of sulfuric acid solution. The high-salt and high-alkali soil conditioner also includes component B colloid, and component B colloid includes the following components by weight: 16-20 parts of chitosan, 1520 parts of ferrous chloride, 3070 parts of hydrochloric acid solution, 8-10 parts of polymethacrylate N,N-dimethylaminoethyl ester, and 13 parts of cross-linking agent. Through the above technical solution, the problem that the existing soil conditioner cannot treat high-salt and high-alkali soil is solved.

[0005] For another example, Chinese patent CN106748540A discloses a conditioner for high-nutrient salinized soil, and its preparation method and application. The conditioner is composed of biochar, nonionic polyacrylamide, anionic polyacrylamide, cationic polyacrylamide, lignite and diatomaceous earth; the mass ratio of the biochar, the nonionic polyacrylamide, the anionic polyacrylamide, the cationic polyacrylamide, the lignite and the diatomaceous earth is 5-10:2-4:2-4:1-3:3-5:1. The conditioner of the present invention solves a series of problems caused by salinization on the soil, such as poor soil physical properties, high ion content and low soil quality, and can reduce soil bulk density and increase soil porosity, which is beneficial to the exchange of water, gas, heat, etc. in the soil and improves soil fertility. At the same time, it reduces the salt ion content and total salt content, reduces its harm to the soil and crops, and thus increases crop yields.

[0006] At present, the improvement of saline-alkali soil is still focused on the coordinated effect of a variety of functional components, and there is still little research on the structural improvement of non-ionic polymers. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a non-ionic high molecular polymer and its application in saline-alkali land improvement, which is obtained by copolymerizing specific monomers in a certain proportion. The obtained non-ionic polymer is applied to saline-alkali soil and has a significant effect of reducing salt and alkali.

[0008] To achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0009] In one aspect, the present invention provides a nonionic high molecular polymer, the preparation method of which comprises the following steps:

[0010] Water, acrylamide, fatty alcohol polyoxyethylene ether and siloxane are mixed, the temperature is adjusted to 20-35° C., a redox initiator composition is added, the polymerization reaction is carried out for 2-5 hours, the temperature is raised to 50-75° C. and kept for 0.5-2 hours, and the product is dried to obtain the non-ionic high molecular polymer.

[0011] Preferably, based on 150 g of water, the amount of acrylamide added is 20-50 g, more preferably 25 g.

[0012] Preferably, based on 150g of water, the added amount of the fatty alcohol polyoxyethylene ether is 1-10g, more preferably 5g.

[0013] Preferably, based on 150 g of water, the amount of siloxane added is 0.3-5 g, more preferably 3 g.

[0014] Preferably, the adjustment temperature is 28°C.

[0015] Preferably, based on 150 g of water, the amount of the redox initiator composition added is 0.05-0.2 g, more preferably 0.15 g.

[0016] Preferably, the redox initiator composition comprises ammonium persulfate and potassium bisulfite, and more preferably, the mass ratio of ammonium persulfate to potassium bisulfite is 1-5:1-5, and more preferably 2:1.

[0017] Preferably, the polymerization reaction time is 3 hours.

[0018] Preferably, after the polymerization reaction, the temperature is raised to 62° C. and then kept at that temperature for 1 hour.

[0019] As a preferred example of the present invention, the method for preparing the nonionic high molecular polymer comprises the following steps:

[0020] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 1.5g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic high molecular polymer.

[0021] Preferably, the molecular weight of the nonionic high molecular polymer is 900,000-1.2 million.

[0022] In yet another aspect, the present invention provides use of the above-mentioned nonionic high molecular polymer in improving saline-alkali land.

[0023] Preferably, in the application, the nonionic high molecular polymer is used by broadcasting or spraying. Broadcasting is more preferred.

[0024] The beneficial effects of the present invention are:

[0025] The present invention prepares a nonionic high molecular polymer by copolymerizing acrylamide, fatty alcohol polyoxyethylene ether and siloxane to obtain a nonionic high molecular polymer with a large molecular weight, and introduces fatty alcohol polyoxyethylene ether and siloxane into the side chain to improve the spatial packaging ability and chelating ability of the macromolecule. At the same time, the siloxane can also ensure the stability of the macromolecular polymer and ensure the long-term salt and alkali reduction effect in the soil. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further explained in conjunction with specific embodiments below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. In the following embodiments, unless otherwise specified, the operating methods used are conventional operating methods, the equipment used are conventional equipment, and the equipment materials used in each embodiment are the same.

[0027] Example 1

[0028] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0029] Example 2

[0030] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 20g of acrylamide, 10g of fatty alcohol polyoxyethylene ether, and 0.3g of siloxane, mix evenly, adjust the temperature to 35°C, pass nitrogen for 30 minutes, add 0.05g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 2 hours, heat to 75°C and keep warm for 2 hours, dry and crush the product to obtain the non-ionic polymer.

[0031] Example 3

[0032] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 50g of acrylamide, 1g of fatty alcohol polyoxyethylene ether, and 5g of siloxane, mix evenly, adjust the temperature to 20°C, pass nitrogen for 30 minutes, add 0.2g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 5 hours, heat to 75°C and keep warm for 0.5 hours, dry and crush the product to obtain the non-ionic polymer.

[0033] Comparative Example 1

[0034] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, and 5g of fatty alcohol polyoxyethylene ether, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, and add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0035] Comparative Example 2

[0036] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of dimethylaminoethyl methacrylate, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic high molecular polymer.

[0037] Comparative Example 3

[0038] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 2g of acrylic acid, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic high molecular polymer.

[0039] Comparative Example 4

[0040] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 15g of fatty alcohol polyoxyethylene ether, and 10g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0041] Results

[0042] 1. Polymer index

[0043] Testing method: Molecular weight and monomer residue were determined according to GB / T 17514-2017. The results are as follows:

[0044]

[0045] The results show that the monomer residue in Comparative Example 4 is relatively large.

[0046] 2. Inspection of the effect of saline-alkali land improvement

[0047] The salt and alkali reduction effects of the polyacrylamide derivatives prepared in the examples and comparative examples were determined by pot tests. The experiment used a Vashvili pot, and the soil was from saline-alkali soil in the Ordos area of ​​the Inner Mongolia Autonomous Region, which was sieved through a 2 mm sieve and air-dried for later use. The initial soil pH value was determined to be 9.30 and the soil salt content was 6.11 g / kg.

[0048] The commercially available nonionic polyacrylamide, the nonionic high molecular polymer prepared in Examples 1-3 and Comparative Examples 1-4 were respectively mixed uniformly with the remaining ingredients according to the following formula to prepare a soil remediation agent: 60 parts of desulfurized gypsum, 50 parts of furfural slag, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent (EM agent of Shandong Beijia Biological), and 5 parts of nonionic high molecular polymer.

[0049] Soil remediation agent No. 0: no polymer added (60 parts of desulfurized gypsum, 50 parts of furfural residue, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent);

[0050] Soil remediation agent No. 1: nonionic high molecular polymer prepared in Example 1;

[0051] Soil remediation agent No. 2: nonionic high molecular polymer prepared in Example 2;

[0052] Soil remediation agent No. 3: nonionic high molecular polymer prepared in Example 3;

[0053] Soil remediation agent No. 4: nonionic high molecular polymer prepared in Comparative Example 1;

[0054] Soil remediation agent No. 5: non-ionic high molecular polymer prepared in Comparative Example 2;

[0055] Soil remediation agent No. 6: non-ionic high molecular polymer prepared in Comparative Example 3;

[0056] Soil remediation agent No. 7: nonionic high molecular polymer prepared in Comparative Example 4;

[0057] Soil remediation agent No. 8: commercially available non-ionic polyacrylamide.

[0058] Each soil remediation agent was fully mixed with the test soil and potted. Each pot contained 15 kg of test soil and 1.8 g of soil remediation agent. A blank group was set up without adding soil remediation agent. After potting, water was poured until the soil reached saturated water holding capacity, and sowed (corn, Zhengdan 958), 10 seeds per pot. After sowing, the surface was covered with about 0.5 cm of dry soil, and the humidity was maintained at 70% of the field water holding capacity. The seedlings were fixed at the three-leaf stage, 3 plants per pot, and the aboveground weight and root weight of the corn (drying weighing method), soil pH value and salt content (conductivity method) were measured at the harvest time. The results are as follows:

[0059]

[0060]

[0061] The results show that after adding the polyacrylamide derivatives prepared in Examples 1-3, the salt and alkali reduction effects are improved, and the corn yield is increased, which is worse than the ordinary commercially available non-ionic polyacrylamide. In Comparative Examples 1 and 3, no siloxane monomer is introduced, and the soil remediation effect and yield increase effect are not as good as those in Examples 1-3. The results of Comparative Examples 2 and 4 show that the polymer of the present invention is more targeted for saline-alkali soil remediation and has a better remediation effect by introducing specific types of monomers and polymerizing at a suitable ratio.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A nonionic high molecular polymer, characterized in that: The preparation method comprises the following steps: Water, acrylamide, fatty alcohol polyoxyethylene ether and siloxane are mixed, the temperature is adjusted to 20-35° C., a redox initiator composition is added, the polymerization reaction is carried out for 2-5 hours, the temperature is raised to 50-75° C. and kept for 0.5-2 hours, and the product is dried to obtain the non-ionic high molecular polymer.

2. The nonionic high molecular polymer according to claim 1, characterized in that Based on 150g of water, the added amount of acrylamide is 20-50g, the added amount of fatty alcohol polyoxyethylene ether is 1-10g, and the added amount of siloxane is 0.3-5g.

3. The nonionic high molecular polymer according to claim 2, characterized in that: Based on 150g of water, the added amount of acrylamide is 25g, the added amount of fatty alcohol polyoxyethylene ether is 5g, and the added amount of siloxane is 3g.

4. The nonionic high molecular polymer according to claim 1, characterized in that The adjustment temperature is 28°C.

5. The nonionic high molecular polymer according to claim 1, characterized in that: Based on 150 g of water, the amount of the redox initiator composition added is 0.05-0.2 g.

6. The nonionic high molecular polymer according to claim 1, characterized in that: The redox initiating composition includes ammonium persulfate and potassium bisulfite.

7. The nonionic high molecular polymer according to claim 6, characterized in that: The mass ratio of the ammonium persulfate to potassium bisulfite is 1-5:1-5.

8. The nonionic high molecular polymer according to claim 1, characterized in that The polymerization reaction time is 3 hours; after the polymerization reaction, the temperature is raised to 62° C. and then kept warm for 1 hour.

9. The nonionic high molecular polymer according to claim 1, characterized in that: The molecular weight of the non-ionic high molecular polymer is 900,000-1.2 million.

10. Use of the nonionic high molecular polymer according to any one of claims 1 to 9 in improving saline-alkali land.

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