CN110894259B - Water-absorbent resin suitable for high-concentration brine and preparation method thereof - Google Patents
Water-absorbent resin suitable for high-concentration brine and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a water-absorbent resin suitable for high-concentration brine and a preparation method thereof. The preparation method of the water absorbent resin comprises the following steps: 1) placing starch in water for gelatinization to obtain gelatinized starch; 2) adding a tertiary amine monomer, unsaturated acid and a cross-linking agent into the gelatinized starch, stirring, adding an initiator after dissolution, uniformly stirring, introducing nitrogen, evacuating, sealing, and reacting at constant temperature; 3) and taking out the product after the reaction is finished, shearing and granulating, soaking the product in absolute ethyl alcohol or acetone, taking out the product and drying the product to obtain the catalyst. According to the invention, the tertiary amine monomer with a specific molecular structure is introduced, so that the obtained water-absorbing resin is not adhered, flocculated, coagulated and hardened in high-concentration saline (the salt mass concentration is 3-10%), and the water-absorbing resin has a good water-absorbing effect, can be naturally degraded, and is expected to be used in the fields of industrial and agricultural high-salt-content sewage treatment, environmental protection and the like. On the other hand, the method is simple and easy to operate.
Description
Technical Field
The invention relates to a water-absorbent resin, in particular to a water-absorbent resin suitable for high-concentration saline water and a preparation method thereof.
Background
The water-absorbing resin (SAP) is a novel functional polymer material, has a three-dimensional network structure, contains a large amount of hydrophilic groups, can absorb water with the dead weight of dozens of times to thousands of times, and is widely applied to the fields of agriculture, forestry and gardening, medical treatment and health, industrial production, daily chemical products and the like.
From the proposal of SAP concept, the water absorption effect in pure water environment is good, however, in real life, the SAPThe application environment is far from ideal, seawater, rainwater, river water, urine and blood are electrolyte solutions dissolved with a large amount of ions or ion clusters, and the application of the SAP in the saline environment has serious problems: as long as a small amount of small molecular salt is present in the water, the water absorption capacity is severely reduced. For example, in NaCl saline (physiological saline) with a mass concentration of 0.9%, the water absorption rate is only a few tenths of the water absorption rate, such as "preparation and swelling kinetics of poly (acrylic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid)/attapulgite composite super absorbent resin" (Wumei;, Qixianhua, science and engineering of high molecular materials, 2019,35(5): 117-. In high-valence ion salt solution such as calcium salt, copper salt, iron salt and the like, SAP even can be condensed and precipitated, and completely loses the water absorption capacity. The reason for this is that: for ionic SAPs, the anions (e.g., carboxylate) on the polymer chain are fixed, while the cations (e.g., hydrogen ions) are mobile. After the cations are diffused outwards, a large number of anions on the polymer chains are repelled by like charges, so that the network structure is promoted to expand, and the phenomenon of swelling is macroscopically expressed. When salt is present in the solution, the anion is ionized by the cation (such as Na)+) Shielding, so that electrostatic repulsion in the SAP is reduced, polymer chains shrink, macroscopically expressed as water absorption capacity is reduced, and when the salt concentration is higher and the cation valence state of the salt is higher, the effect is more obvious.
Currently, studies on the improvement of the salt tolerance of SAP are mainly focused on the absorption of low-concentration saline (particularly, physiological saline), and the absorption of extra-high-concentration saline, higher-order ionic saline is rarely involved. The content directly affects the application field and the actual effect of the SAP, for example, when the SAP is used for soil moisture preservation and fertilizer slow release in desert tree planting, the water to be absorbed usually needs to contain a large amount of nutrients such as nitrogen, phosphorus, potassium and the like, and the substances are various salts with high concentration.
Therefore, it is necessary to prepare a new type of zwitterionic water-absorbing resin which has relatively good absorption effect on high-concentration saline.
Disclosure of Invention
The invention aims to solve the technical problem that the existing conventional acrylic acid series water-absorbing materials are easy to adhere, flocculate, aggregate and harden in high-concentration saline water, and provides a water-absorbing resin suitable for high-concentration saline water and a preparation method thereof.
The water-absorbing resin suitable for high-concentration brine has the following structure:
wherein x is 0.05 to 0.1, y is 0.05 to 0.5, z is 0.2 to 0.5, m is 0.0001 to 0.0005, and x + y + z + m is 1; n is 0 to 3, and k is 0 to 3.
The preparation method of the water absorbent resin suitable for the high-concentration brine comprises the following steps:
1) placing starch in water for gelatinization to obtain gelatinized starch;
2) adding a tertiary amine monomer, unsaturated acid and a cross-linking agent into the gelatinized starch, stirring, adding an initiator after dissolution, uniformly stirring, introducing nitrogen, evacuating, sealing, and reacting at constant temperature; wherein the content of the first and second substances,
the tertiary amine monomer is a compound, the molecular structure of the tertiary amine monomer is represented by an acrylamide derivative, and the tertiary amine monomer simultaneously has an acrylamide group and a tertiary amine group, and the molar ratio of the two groups is 1: 1, connecting two groups by methylene, wherein the number of the methylene is 3-6;
the unsaturated acid is a compound, the molecular structure of the unsaturated acid is represented by an olefin carboxylic acid derivative, and the unsaturated acid simultaneously has an olefin double bond and a carboxyl group, and the molar ratio of the two groups is 1: 1, connecting two groups by methylene, wherein the number of the methylene is 0-3;
the mass ratio of the starch to the tertiary amine monomer to the unsaturated acid to the cross-linking agent to the initiator is 1: 2-15: 5-10: 0.005-0.02: 0.001 to 0.1.
3) And taking out the product after the reaction is finished, shearing and granulating, soaking the product in absolute ethyl alcohol or acetone, taking out the product and drying the product to obtain the catalyst.
In the preparation method of the invention, the starch and the initiator are all conventional choices in the prior art, and specifically, the starch can be one or a combination of more than two of potato starch, cereal starch, corn starch, bean starch and the like. The initiator may be one or a combination of two or more selected from ammonium persulfate, potassium persulfate, ammonium ceric nitrate, and ceric sulfate.
In the step 1) of the preparation method, the operation of gelatinizing the starch in water is the same as that of the prior art, generally, the starch is placed in water and heated to 60-85 ℃ for gelatinizing for 0.5-2 h, wherein the mass ratio of the starch to the water is preferably 5-10: 100.
in step 2) of the above preparation method, the tertiary amine monomer may be one or a combination of two or more selected from dimethylaminopropyl methacrylamide, dimethylaminobutyl methacrylamide and dimethylaminopentyl methacrylamide; the unsaturated acid can be one or more of acrylic acid, butenoic acid and pentenoic acid; the cross-linking agent is N, N' -Methylene Bisacrylamide (MBA) and/or divinyl sulfone (DVS). In the step, the reaction is preferably carried out at 50-60 ℃, and the reaction time is usually 30-60 min.
In order to facilitate the reaction, the tertiary amine monomer, the unsaturated acid and the cross-linking agent are preferably dissolved by water and then added into the gelatinized starch, and the amount of the water is preferably controlled to be 0.8-2 times of the sum of the mass of the tertiary amine monomer, the mass of the unsaturated acid and the mass of the cross-linking agent. In the same way, the initiator is preferably dissolved by water and then added into the gelatinized starch, and the using amount of the water is preferably controlled to be 2-5 times of that of the initiator.
In the step 3) of the preparation method, the temperature is reduced to room temperature after the reaction is finished, the product is taken out, and the product obtained by the reaction is observed to be light yellow or milky elastic gel solid. The method comprises the steps of soaking the particles for 24-48 hours by using absolute ethyl alcohol or acetone to purify the particles, taking out the particles, drying the particles at 50-80 ℃, and then crushing and sieving the particles (the aperture is preferably 50-200 meshes) to obtain the water-absorbent resin suitable for high-concentration saline water.
The water-absorbing resin is suitable for fresh water and low-concentration saline water, but is particularly suitable for high-concentration saline water, wherein the high-concentration saline water refers to saline water with the salt mass concentration of 3-10%.
Compared with the prior art, the tertiary amine monomer with a specific molecular structure is introduced, so that the water-absorbing resin is not adhered, flocculated, precipitated and hardened in high-concentration saline (the salt mass concentration is 3-10%), has a good water-absorbing effect, can be naturally degraded, and is expected to be used in the fields of industrial and agricultural high-salt-content sewage treatment, environmental protection and the like. On the other hand, the method is simple and easy to operate.
Drawings
FIG. 1 is an infrared spectrum of a water-absorbent resin obtained in example 1 of the present invention;
FIG. 2 is a graph showing the water absorption capacity of the water-absorbent resin obtained in example 1 of the present invention in aqueous solutions of different chlorides;
FIG. 3 is a graph showing the water absorption capacity of the water absorbent resin obtained in example 1 of the present invention in saline solutions of various sulfates.
Detailed Description
The present invention will be better understood from the following detailed description of specific examples, which should not be construed as limiting the scope of the present invention.
Example 1
1) Mixing 3g of starch (corn starch) and 35g of pure water, putting into a flask, heating to 85 ℃, magnetically stirring, condensing and refluxing for 1h (at the moment, the system is uniform and transparent), cooling to 50 ℃, and preserving heat to obtain gelatinized starch;
2) adding 15g of tertiary amine monomer (dimethylamino propyl methacrylamide), 15g of unsaturated acid (acrylic acid) and 0.015g of cross-linking agent (MBA) into gelatinized starch, continuously stirring, adding 0.3g of initiator (ammonium persulfate) after completely dissolving, uniformly stirring, introducing nitrogen, evacuating, sealing, and then placing in an oven at 60 ℃ for reacting for 60min (at the moment, the materials in the flask have no fluidity);
3) and after the reaction is finished, cooling, taking out the product, shearing into pieces, soaking the cut product in absolute ethyl alcohol which is 10 times of the product in mass for 48h, taking out the cut product, drying the cut product in a 50 ℃ drying oven, crushing the dried product, sieving the crushed product with a 100-mesh sieve, and collecting undersize products to obtain 30.2g of the water-absorbing resin (white powdery solid) suitable for the high-concentration saline water.
The water-absorbent resin obtained in this example was pressed into a tablet with potassium bromide, and the infrared spectrum thereof was as shown in FIG. 1. Wherein, 3350cm-1And 2920cm-1Is a starch hydroxyl characteristic peak of 1012cm-1Is C-OH stretching vibration peak in glucose structural unit, 1690cm-1Has a strong absorption peak of stretching vibration of the carboxylic acid carbonyl dimer and a C-N vibration peak (1120 cm)-1) And a C-N characteristic peak (1080 cm)-1)。
Example 2
Example 1 was repeated except that: the crosslinking agent is changed into divinyl sulfone, and the initiator is changed into potassium persulfate. 27.63g of a water-absorbent resin (white powdery solid) suitable for brine having a high concentration was finally obtained.
Example 3
1) Mixing 3g of starch (potato starch) with 60g of pure water, putting into a flask, heating to 75 ℃, magnetically stirring, condensing and refluxing for 2 hours (at the moment, the system is uniform and transparent), cooling to 55 ℃, and keeping the temperature to obtain gelatinized starch;
2) dissolving 6g of tertiary amine monomer (dimethylamino butyl methacrylamide), 30g of unsaturated acid (butenoic acid) and 0.03g of cross-linking agent (MBA) in 20g of pure water to obtain a mixed solution; adding the mixed solution into the gelatinized starch obtained in the step 1), stirring uniformly, adding 0.015g of initiator (ammonium persulfate), stirring uniformly, introducing nitrogen, evacuating, sealing, and placing in a 50 ℃ oven for reaction for 60min (at the moment, the materials in the flask have no flowability);
3) and after the reaction is finished, cooling, taking out the product, shearing into pieces, soaking the cut product in absolute ethyl alcohol which is 10 times of the product in mass for 48h, taking out the cut product, drying the cut product in a 50 ℃ drying oven, crushing the dried product, sieving the crushed product with a 100-mesh sieve, and collecting undersize products to obtain 33.91g of the water-absorbing resin (white powdery solid) suitable for the high-concentration saline water.
Example 4
1) Mixing 3g of starch (potato starch) with 60g of pure water, putting into a flask, heating to 60 ℃, magnetically stirring, condensing and refluxing for 2 hours (at the moment, the system is uniform and transparent), cooling to 50 ℃, and preserving heat to obtain gelatinized starch;
2) adding 30g of tertiary amine monomer (dimethylamino amyl methacrylamide), 24g of unsaturated acid (pentenoic acid) and 0.06g of cross-linking agent (polyethylene glycol) into gelatinized starch, continuously stirring, adding 0.003g of initiator (ammonium ceric nitrate) after completely dissolving, uniformly stirring, introducing nitrogen, evacuating, sealing, and then placing in an oven at 60 ℃ for reacting for 40min (at the moment, the materials in the flask have no fluidity);
3) and after the reaction is finished, cooling, taking out the product, shearing into pieces, soaking the cut product in absolute ethyl alcohol which is 10 times of the product in mass for 48h, taking out the cut product, drying the cut product in a 50 ℃ drying oven, crushing the dried product, sieving the crushed product with a 100-mesh sieve, and collecting undersize products to obtain 49.28g of the water-absorbing resin (white powdery solid) suitable for the high-concentration saline water.
Experimental example 1: the water absorption performance of the water absorption resin in chloride brine is measured
A plurality of samples of the water-absorbent resin obtained in example 1 were taken, each sample weighing 0.2g, and each sample was placed in 100mL of chloride aqueous solutions with different concentrations, soaked at room temperature for 24 hours, taken out, placed on a 100-mesh nylon net until dripping did not occur, and weighed to calculate the water absorption, and the results are shown in FIG. 2.
As can be seen from FIG. 2, NaCl and CaCl were added at 3 to 10 mass%2Or AlCl3In the aqueous solution of (3), the water absorption of the sample is more than or equal to 16g/g, and the electrolyte coagulation phenomenon can not occur.
Experimental example 2: the water absorption performance of the water absorption resin in the sulfate water is measured
A plurality of samples of the water-absorbent resin obtained in example 1 were taken, each sample weighing 0.2g, and each sample was placed in 100mL of sulfate aqueous solutions with different concentrations, soaked at room temperature for 24 hours, taken out, placed on a 100-mesh nylon net until dripping did not occur, and weighed to calculate the water absorption, and the results are shown in FIG. 3.
As can be seen from FIG. 3, Na is present at a mass concentration of 3 to 10%2SO4Or CuSO4In the saline, the water absorption of the sample is more than or equal to 16g/g, and the electrolyte coagulation phenomenon can not occur.
The present invention is described in further detail with reference to the embodiments, but the embodiments of the present invention are not limited to the descriptions. Numerous simplifications or substitutions which may be made in the field of the invention without departing from the spirit thereof are intended to be included within the scope of the invention.
Claims (10)
1. A water-absorbent resin suitable for high-concentration brine, which has the following structure:
wherein x is 0.05 to 0.1, y is 0.05 to 0.5, z is 0.2 to 0.5, m is 0.0001 to 0.0005, and x + y + z + m is 1; n is 0 to 3, and k is 0 to 3.
2. The method for preparing a water absorbent resin suitable for highly concentrated brine as claimed in claim 1, comprising the steps of:
1) placing starch in water for gelatinization to obtain gelatinized starch;
2) adding a tertiary amine monomer, unsaturated acid and a cross-linking agent into the gelatinized starch, stirring, adding an initiator after dissolution, uniformly stirring, introducing nitrogen, evacuating, sealing, and reacting at constant temperature; wherein the content of the first and second substances,
the tertiary amine monomer is a compound, the molecular structure of the tertiary amine monomer is represented by an acrylamide derivative, and the tertiary amine monomer simultaneously has an acrylamide group and a tertiary amine group, and the molar ratio of the two groups is 1: 1, connecting two groups by methylene, wherein the number of the methylene is 3-6;
the unsaturated acid is a compound, the molecular structure of the unsaturated acid is represented by an olefin carboxylic acid derivative, and the unsaturated acid simultaneously has an olefin double bond and a carboxyl group, and the molar ratio of the two groups is 1: 1, connecting two groups by methylene, wherein the number of the methylene is 0-3;
the mass ratio of the starch to the tertiary amine monomer to the unsaturated acid to the cross-linking agent to the initiator is 1: 2-15: 5-10: 0.005-0.02: 0.001 to 0.1;
3) and taking out the product after the reaction is finished, shearing and granulating, soaking the product in absolute ethyl alcohol or acetone, taking out the product and drying the product to obtain the catalyst.
3. The method of claim 2, wherein: in the step 1), the starch is one or a combination of more than two of potato starch, cereal starch, corn starch and bean starch.
4. The method of claim 2, wherein: in the step 2), the cross-linking agent is N, N' -methylene bisacrylamide.
5. The method of claim 2, wherein: in the step 2), the initiator is one or a combination of more than two of ammonium persulfate, potassium persulfate, ammonium ceric nitrate and ceric sulfate.
6. The method of claim 2, wherein: in the step 2), the reaction is carried out at 50-60 ℃.
7. The method of claim 2, wherein: in the step 2), the tertiary amine monomer is one or a combination of more than two of dimethylamino propyl methacrylamide, dimethylamino butyl methacrylamide and dimethylamino pentyl methacrylamide.
8. The method of claim 2, wherein: in the step 2), the unsaturated acid is one or a combination of more than two of acrylic acid, butenoic acid and pentenoic acid.
9. The production method according to any one of claims 2 to 8, characterized in that: in the step 2), the tertiary amine monomer, the unsaturated acid and the cross-linking agent are dissolved by water and then added into the gelatinized starch.
10. The method of claim 9, wherein: the mass ratio of the mass sum of the tertiary amine monomer, the unsaturated acid and the cross-linking agent to the water is 0.8-2: 1.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4076663A (en) * | 1975-03-27 | 1978-02-28 | Sanyo Chemical Industries, Ltd. | Water absorbing starch resins |
| JPS5521041B2 (en) * | 1977-10-05 | 1980-06-06 | ||
| CN102408510A (en) * | 2011-09-09 | 2012-04-11 | 宜兴丹森科技有限公司 | Preparation method for super absorbent resin |
| CN105399900A (en) * | 2015-12-22 | 2016-03-16 | 兰州大学 | Preparation method of superabsorbent resin |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4076663A (en) * | 1975-03-27 | 1978-02-28 | Sanyo Chemical Industries, Ltd. | Water absorbing starch resins |
| JPS5521041B2 (en) * | 1977-10-05 | 1980-06-06 | ||
| CN102408510A (en) * | 2011-09-09 | 2012-04-11 | 宜兴丹森科技有限公司 | Preparation method for super absorbent resin |
| CN105399900A (en) * | 2015-12-22 | 2016-03-16 | 兰州大学 | Preparation method of superabsorbent resin |
Non-Patent Citations (1)
| Title |
|---|
| 耐盐性高吸水树脂的研究进展;张宇等;《合成材料老化与应用》;20031231;第42-47页 * |
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