Environment-friendly degradable salt-resistant superabsorbent polymer and preparation and degradation method thereof

Abstract

This invention discloses a method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin. The method includes mixing 10-15% polyvinyl alcohol, 10-15% humic acid, and 40-50% water, heating to 50-80°C, adding a small amount of solid alkali, and cooling to 30-50°C after the solid alkali dissolves. Then, 6-12% urea, a mixed solution of 9-15% BES-Na and a metal ion-soluble salt, 1-5% sodium p-aminobenzenesulfonate, 0.01-0.05% manganese dioxide, and 1-4% hydrogen peroxide are added. The mixture is rapidly stirred to obtain a loose, viscous system, and finally dried. The total mass percentage of all components is 100%. This invention also discloses a method for degrading the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin, including preparing EDTA to a concentration of 0.01-0.1 mol / L. ‑1 The resin is crushed and then mixed with the salt solution. The mixture is stirred and heated to complete the degradation process.

Description

Technical Field

[0001] This invention belongs to the field of superabsorbent resin technology, and relates to green, environmentally friendly, biodegradable, salt-resistant superabsorbent resin and its preparation and degradation methods. Background Technology

[0002] Superabsorbent polymers (SAPs) are novel polymer materials containing numerous hydrophilic groups and slight cross-linking. Due to their strong water absorption and retention properties, they are widely used in agriculture, forestry, daily chemicals, pharmaceuticals, environmental protection, food, and wastewater treatment. However, their high production costs, poor environmental friendliness, poor salt resistance, and difficulty in degradation limit their application performance. Therefore, finding green, environmentally friendly, and inexpensive salt-resistant SAPs and researching feasible degradation methods are of great significance for improving the performance of SAPs and expanding their application scope and fields.

[0003] The current status and future direction of superabsorbent polymer (SAP) development are as follows: (1) Quality and overall performance of superabsorbent resin Since the water absorption capacity, salt resistance, and strength of superabsorbent resins are usually mutually restrictive, it is an urgent problem to be solved in future research to actively develop and research more effective methods to improve the overall performance of products, based on the needs of various applications, by using appropriate raw materials, additives, process equipment, and conditions, while ensuring that the superabsorbent resin has good water absorption and retention properties.

[0004] (2) Develop green and biodegradable resources and strengthen research on organic-inorganic composite water-absorbing resins. Currently, most commercially available superabsorbent polymers are polyacrylic acid synthetic resins with high production costs and poor biodegradability. Therefore, we can start with the raw materials and process synthetic superabsorbent polymers with inorganic minerals, natural polymer materials, etc., to improve their compatibility, thereby preparing low-cost, high-performance superabsorbent composite materials and realizing the recycling and sustainable use of polymer materials.

[0005] (3) Improvement and optimization of the initiation system and synthesis process The existing method for preparing superabsorbent polymers is polymerization, which is costly, complex, and difficult to process, making it difficult to develop on a large scale. Therefore, it is urgent to establish a simpler polymerization process and evaluation system. Summary of the Invention

[0006] The first objective of this invention is to provide a green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin preparation method, which solves the problems of complex synthesis process, poor salt resistance, and difficulty in degradation of existing superabsorbent resins.

[0007] The second objective of this invention is to provide a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin.

[0008] The third objective of this invention is to provide a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method.

[0009] The first technical solution adopted in this invention is a method for preparing a green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin, comprising, by mass percentage, mixing 10-15% polyvinyl alcohol, 10-15% humic acid, and 40-50% water evenly, heating to 50-80°C, adding 0.01-0.05% solid alkali, waiting for the solid alkali to dissolve, cooling to 30-50°C, and then sequentially adding 6-12% urea, 9-15% a mixed solution of BES-Na and metal ion-soluble salts, 1-5% sodium p-aminobenzenesulfonate, 0.01-0.05% manganese dioxide, and 1-4% hydrogen peroxide, rapidly stirring to obtain a loose and viscous system, and drying to obtain a porous, green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin, wherein the sum of the mass percentages of the above components is 100%.

[0010] Specifically, the following steps are included: Step 1: Mix 10-15% polyvinyl alcohol, 10-15% humic acid and 40-50% water by weight percentage, stir evenly, and heat to 50-80℃. Then add 0.01-0.05% solid alkali and keep warm to dissolve the solid alkali. Step 2: Lower the temperature of the reaction system to 30-50°C, add 6-12% urea, maintain a constant temperature, and stir thoroughly for 30 minutes to ensure that the urea is completely dissolved and evenly dispersed in the reaction system.

[0011] Step 3: Add a mixed solution of 9-15% BES-Na and metal ion soluble salts, maintain a constant temperature of 30-50℃, and stir thoroughly for about 30 minutes to ensure that the added substances are evenly dispersed in the reaction system and react completely. Step 4: Add 1-5% sodium p-aminobenzenesulfonate, maintain a constant temperature of 30-50℃, and stir thoroughly for about 30 minutes to ensure that the added substance is evenly dispersed in the reaction system. Step 5: Add 0.01% to 0.05% manganese dioxide, maintain a constant temperature of 30 to 50°C, and stir thoroughly for about 30 minutes to ensure that the added substance is evenly dispersed in the reaction system. Step 6: Add 1%–4% hydrogen peroxide and stir rapidly for 30–60 seconds to obtain a loose and viscous system; Step 7: Dry the loose and viscous system at 50-100 ℃ to obtain a porous, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin.

[0012] Humic acids include one or more of black humic acid, yellow humic acid, and brown humic acid.

[0013] In step 3, the concentration of the mixed solution of BES-Na and the metal ion soluble salt is 0.1 mol / L to 1 mol / L. BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the metal ion soluble salt is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0014] In step 6, add 1% to 4% hydrogen peroxide and stir rapidly for 30 to 60 seconds at a stirring speed of 500 to 1000 rpm.

[0015] The second technical solution adopted in this invention is a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared according to the above preparation method. The superabsorbent resin has a loose pore structure inside and a water absorption rate of 1500g / g to 2000g / g. When using a 0.9% NaCl solution, the salt absorption rate is 300g / g to 350g / g.

[0016] The third technical solution adopted in this invention is a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method, comprising the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water to prepare a solution with a concentration of 0.01 mol·L⁻¹. -1 ~0.1mol·L -1 Salt solution; Step 2: By mass fraction, 10%–40% of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin is pulverized to the size of rice grains and mixed evenly with 60%–90% of the salt solution prepared in Step 1, wherein the sum of the mass percentages of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin and the salt solution is 100%. Step 3: Adjust the acidity of the system to between pH 1 and pH 2. pH 1 is the minimum pH value at which metal ions in the soluble salt of metal ions can coordinate with disodium ethylenediaminetetraacetate (EDTA). pH 2 is the pH value at which metal ions in the soluble salt of metal ions hydrolyze. Stir and heat to 50-80°C, and stir at a constant temperature for 1-10 hours. The green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin is completely degraded.

[0017] In step 1, disodium ethylenediaminetetraacetate (EDTA) is mixed with water, heated to 50-80°C, and stirred until completely dissolved to prepare a solution with a concentration of 0.01 mol·L⁻¹. -1 ~0.1mol·L -1 A salt solution.

[0018] The beneficial effects of this invention are as follows: (1) In the process of preparing green, environmentally friendly, biodegradable, salt-resistant superabsorbent resin, non-toxic or low-toxic metal ions that are easy to form complexes are used as crosslinking agents. Non-toxic, green, environmentally friendly, and inexpensive humic acid and polyvinyl alcohol are crosslinked together through coordination polymerization to prepare superabsorbent resin. This method avoids the problems of high cost, complex process and difficult post-processing of superabsorbent resin preparation by existing free radical initiation system, and also improves the environmental performance of the product. (2) By forming a stable five-membered ring complex with polyvinyl alcohol and sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate (BES-Na) in the metal ion soluble salt, a large number of metal ions (M) and BES-Na are fixed inside the superabsorbent resin. This firstly creates a large concentration difference of M ions between the resin and the external environment, which greatly improves the water absorption and salt resistance of the resin. Secondly, the introduction of a large number of strongly hydrophilic sulfonic acid groups in the resin and the foaming of the foaming agent hydrogen peroxide greatly improve the water absorption rate of the resin. (3) The degradation of the resin is achieved by using EDTA, a disodium ethylenediaminetetraacetate salt (EDTA) which has a strong coordination ability with metal ion M in the soluble salt of metal ions and whose complex with metal ion M is easily soluble in water, to coordinate with the metal ions in the resin. This process breaks down the resin skeleton formed by the coordination polymerization of metal ions, thereby achieving the purpose of degrading the resin. This method is simple, low-cost, easy to operate and controllable, has a short degradation time, and is harmless to the human body and the environment. Attached Figure Description

[0019] Figure 1 This is a scanning electron microscope (SEM) image of the interior of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared in Example 1 of this invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 10% polyvinyl alcohol, 15% humic acid and 50% water by weight percentage, stir well and heat to 70 °C, then add 0.05% solid alkali and keep warm to dissolve the solid alkali for 50 min. Step 2: Lower the temperature of the reaction system to 50°C, add 12% urea, maintain a constant temperature, and stir thoroughly for 30 minutes to ensure that the urea is completely dissolved and evenly dispersed in the reaction system. Step 3: Add a mixed solution of 9.94% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and MgSO4, a soluble salt of metal ions, maintain a constant temperature of 50℃, and stir thoroughly for 30 minutes to ensure that it is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 0.1 mol·L⁻¹. -1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0022] Step 4: Add 2% sodium p-aminobenzenesulfonate, maintain a constant temperature of 50°C, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system; Step 5: Add 0.01% manganese dioxide, maintain a constant temperature of 50℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 1% hydrogen peroxide and stir rapidly at a stirring speed of 500 rpm for 30 seconds to obtain a loose and viscous system. The sum of the mass percentages of the above components is 100%.

[0023] Step 7: Dry the loose and viscous system at 50°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin.

[0024] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 1 was analyzed by SEM. The internal scanning electron microscope image is shown below. Figure 1 As shown, from Figure 1 As can be seen, the resin prepared by the method of the present invention has a large number of pore structures inside, and these loose pore structures can store a large amount of water.

[0025] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 1 was tested for water absorption. Its water absorption rate was 1560 g / g, and its salt absorption rate was 302 g / g when using a 0.9% NaCl solution.

[0026] Example 2 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 15% polyvinyl alcohol, 10% humic acid and 49% water by weight percentage, stir well and heat to 80 °C, then add 0.02% solid alkali and keep warm to dissolve the solid alkali for 60 min. Step 2: Lower the temperature of the reaction system to 40°C, add 8% urea, maintain a constant temperature, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system. Step 3: Add a mixed solution of 11.9% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and FeCl3, a soluble salt of metal ions, maintain a constant temperature of 40℃, and stir thoroughly for 35 minutes to ensure that it is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 0.5 mol·L⁻¹. -1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0027] Step 4: Add 4% sodium p-aminobenzenesulfonate, maintain a constant temperature of 40°C, and stir thoroughly for 30 minutes to ensure uniform dispersion in the reaction system; Step 5: Add 0.02% manganese dioxide, maintain a constant temperature of 40℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 2.06% hydrogen peroxide and stir rapidly at a stirring speed of 600 rpm for 60 seconds to obtain a loose and viscous system; The sum of the mass percentages of the above components is 100%.

[0028] Step 7: Dry the loose and viscous system at 80°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant superabsorbent resin. This superabsorbent resin has a large number of loose pore structures inside.

[0029] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 2 was tested for water absorption. Its water absorption rate was 1832 g / g, and its salt absorption rate was 334 g / g when using a 0.9% NaCl solution.

[0030] Example 3 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 13% polyvinyl alcohol, 10.9% humic acid and 48% water by weight percentage, stir well and heat to 50 °C, then add 0.01% solid alkali and keep warm to dissolve the solid alkali for 40 min. Step 2: Lower the temperature of the reaction system to 30°C, add 7% urea, maintain a constant temperature, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system. Step 3: Add a mixed solution of 15% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and metal ion soluble salt AlCl3, maintain a constant temperature of 30℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 0.5 mol·L⁻¹. -1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0031] Step 4: Add 3% sodium p-aminobenzenesulfonate, maintain a constant temperature of 30°C, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system; Step 5: Add 0.03% manganese dioxide, maintain a constant temperature of 30℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 3.06% hydrogen peroxide and stir rapidly at a stirring speed of 700 rpm for 50 seconds to obtain a loose and viscous system; The sum of the mass percentages of the above components is 100%.

[0032] Step 7: Dry the loose and viscous system at 70°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin.

[0033] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 3 was tested and found to have a large number of pore structures inside, which can store a large amount of water.

[0034] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 3 was tested for water absorption. Its water absorption rate was 1710 g / g, and its salt absorption rate was 323 g / g when using a 0.9% NaCl solution.

[0035] Example 4 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 11.9% polyvinyl alcohol, 13% humic acid and 40% water by weight percentage, stir well and heat to 60 °C, then add 0.03% solid alkali and keep warm to dissolve the solid alkali for 30 min. Step 2: Lower the temperature of the reaction system to 45°C, add 11.02% urea, maintain a constant temperature, and stir thoroughly for about 30 minutes to ensure that the urea is completely dissolved and evenly dispersed in the reaction system. Step 3: Add a mixed solution of 15% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and BiCl3, a soluble salt of metal ions. Maintain a constant temperature of 45℃ and stir thoroughly for about 30 minutes to ensure that the solution is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 0.6 mol·L⁻¹.-1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0036] Step 4: Add 5% sodium p-aminobenzenesulfonate, maintain a constant temperature of 45℃, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system; Step 5: Add 0.05% manganese dioxide, maintain a constant temperature of 45℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 4% hydrogen peroxide and stir rapidly at 800 rpm for 40 seconds to obtain a loose and viscous system. The sum of the mass percentages of the above components is 100%.

[0037] Step 7: Dry the loose and viscous system at 60°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant superabsorbent resin. This superabsorbent resin has a large number of loose pore structures inside.

[0038] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 4 was tested for water absorption. Its water absorption rate was 2000 g / g, and its salt absorption rate was 350 g / g when using a 0.9% NaCl solution.

[0039] Example 5 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 10% polyvinyl alcohol, 15% humic acid and 45.9% water by weight, stir well and heat to 75 ℃, then add 0.05% solid alkali and keep warm to dissolve the solid alkali for 45 min. Step 2: Lower the temperature of the reaction system to 35°C, add 6% urea, maintain a constant temperature, and stir thoroughly for about 30 minutes to ensure that the urea is completely dissolved and evenly dispersed in the reaction system. Step 3: Add a mixed solution of 11% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and ZnCl2, a soluble salt of metal ions, maintain a constant temperature of 35℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 0.8 mol·L⁻¹. -1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0040] Step 4: Add 4% sodium p-aminobenzenesulfonate, maintain a constant temperature of 35°C, and stir thoroughly for about 30 minutes to ensure uniform dispersion in the reaction system; Step 5: Add 0.05% manganese dioxide, maintain a constant temperature of 35℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 4% hydrogen peroxide and stir rapidly at a stirring speed of 900 rpm for 45 seconds to obtain a loose and viscous system. The sum of the mass percentages of the above components is 100%.

[0041] Step 7: Dry the loose and viscous system at 75°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant superabsorbent resin. This superabsorbent resin has a large number of loose pore structures inside.

[0042] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 5 was tested for water absorption. Its water absorption rate was 1500 g / g, and its salt absorption rate was 300 g / g when using a 0.9% NaCl solution.

[0043] Example 6 A method for preparing a green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin specifically includes the following steps: Step 1: Mix 13.92% polyvinyl alcohol, 12% humic acid and 49% water by weight percentage, stir well and heat to 65 °C, then add 0.04% solid alkali and keep warm to dissolve the solid alkali for 55 min. Step 2: Lower the temperature of the reaction system to 40°C, add 12% urea, maintain a constant temperature, and stir thoroughly for about 30 minutes to ensure that the urea is completely dissolved and evenly dispersed in the reaction system. Step 3: Add a mixed solution of 9% N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate sodium (BES-Na) and FeCl2, a soluble salt of metal ions. Maintain a constant temperature of 40℃ and stir thoroughly for about 30 minutes to ensure that the solution is evenly dispersed in the reaction system and reacts completely. In step 3, the concentration of the mixed solution of BES-Na and the soluble salt of metal ions is 1 mol·L⁻¹. -1 BES-Na is sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, and the metal ion in the soluble salt of metal ions is M. The molar ratio of BES-Na to M in the mixed solution is 1:1.

[0044] Step 4: Add 1% sodium p-aminobenzenesulfonate, maintain a constant temperature of 40°C, and stir thoroughly for about 30 minutes to dissolve and disperse evenly in the reaction system; Step 5: Add 0.04% manganese dioxide, maintain a constant temperature of 40℃, and stir thoroughly for about 30 minutes to ensure that it is evenly dispersed in the reaction system; Step 6: Add 3% hydrogen peroxide and stir at 1000 rpm for 55 seconds to obtain a loose and viscous system. The sum of the mass percentages of the above components is 100%.

[0045] Step 7: Dry the loose and viscous system at 65°C to obtain a porous, environmentally friendly, biodegradable, salt-resistant superabsorbent resin. This superabsorbent resin has a large number of loose pore structures inside.

[0046] The porous, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 6 was tested for water absorption. Its water absorption rate was 1590 g / g, and its salt absorption rate was 315 g / g when using a 0.9% NaCl solution.

[0047] Example 7 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 50°C, and stir until completely dissolved to prepare a solution with a concentration of 0.01 mol / L. -1 Salt solution; Step 2: By mass fraction, 10% of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared in Example 1 is crushed to the size of rice grains and mixed evenly with 90% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=10 (Mg 2+ The minimum pH at which EDTA can react is 9.7, and Mg... 2+ The system was stirred and heated to 50 °C and stirred at a constant temperature for 1 hour. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

[0048] Example 8 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 60°C, and stir until completely dissolved to prepare a solution with a concentration of 0.03 mol / L. -1 Salt solution; Step 2: By mass fraction, 40% of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared in Example 2 is pulverized to the size of rice grains and mixed evenly with 60% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=1.5 (Fe 3+ The minimum pH at which EDTA can react is 1.2, Fe 3+The system was stirred and heated to 80 °C and stirred at a constant temperature for 10 hours. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

[0049] Example 9 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 70°C, and stir until completely dissolved to prepare a solution with a concentration of 0.03 mol / L. -1 Salt solution; Step 2: By mass fraction, 20% of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared in Example 3 is pulverized to the size of rice grains and mixed evenly with 80% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=4.5 (Al). 3+ The minimum pH at which Al can react with EDTA is 4.0. 3+ The system was stirred and heated to 70 °C and stirred at a constant temperature for 7 hours. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

[0050] Example 10 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 80°C, and stir until completely dissolved to prepare a solution with a concentration of 0.08 mol / L. -1 Salt solution; Step 2: By mass fraction, 30% of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared in Example 4 is pulverized to the size of rice grains and mixed evenly with 70% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=1 (Bi 3+ The minimum pH at which Bi can react with EDTA is 0.7. 3+ The system was stirred and heated to 60 °C and stirred at a constant temperature for 5 hours. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

[0051] Example 11 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 75°C, and stir until completely dissolved to prepare a solution with a concentration of 0.05 mol / L. -1 Salt solution; Step 2: By mass fraction, 25% of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 5 is pulverized to the size of rice grains and mixed evenly with 75% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=8 (Zn 2+ The minimum pH at which Zn reacts with EDTA is 3.8. 2+ The system was stirred and heated to 75 °C and stirred at a constant temperature for 8 hours. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

[0052] Example 12 A green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin degradation method includes the following steps: Step 1: Mix disodium ethylenediaminetetraacetate (EDTA) with water, heat to 65°C, and stir until completely dissolved to prepare a solution with a concentration of 0.06 mol / L. -1 Salt solution; Step 2: By mass fraction, 35% of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin prepared in Example 6 is pulverized to the size of rice grains and mixed evenly with 65% of the salt solution prepared in Step 1. Step 3, adjust the acidity of the system to pH=8 (Fe 2+ The minimum pH at which EDTA can react is 4.8, Fe 2+ The system was stirred and heated to 65 °C and stirred at a constant temperature for 9 hours. The system became homogeneous, indicating that the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin had been completely degraded.

Claims

1. A method for preparing green and environmentally friendly degradable salt-resistant superabsorbent resin, characterized in that, The process involves mixing 10-15% polyvinyl alcohol, 10-15% humic acid, and 40-50% water by weight percentage, heating to 50-80°C, adding 0.01-0.05% solid alkali, and cooling to 30-50°C after the solid alkali dissolves. Then, 6-12% urea, 9-15% a mixed solution of BES-Na and a metal ion-soluble salt, 1-5% sodium p-aminobenzenesulfonate, 0.01-0.05% manganese dioxide, and 1-4% hydrogen peroxide are added sequentially. The mixture is rapidly stirred to obtain a loose and viscous system. After drying, a porous, environmentally friendly, biodegradable, salt-resistant, and highly absorbent resin is obtained. The sum of the weight percentages of all the above components is 100%.

2. The preparation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Mix 10-15% polyvinyl alcohol, 10-15% humic acid and 40-50% water by weight percentage, stir evenly, and heat to 50-80 ℃. Then add 0.01-0.05% solid alkali and keep warm to dissolve the solid alkali. Step 2: Lower the temperature of the reaction system to 30-50°C, add 6-12% urea, maintain a constant temperature, and stir to completely dissolve the urea and disperse it evenly in the reaction system. Step 3: Add a mixed solution of 9-15% BES-Na and metal ion soluble salt, maintain a constant temperature of 30-50℃, and stir to disperse it evenly in the reaction system. Step 4: Add 1-5% sodium p-aminobenzenesulfonate, maintain a constant temperature of 30-50℃, and stir to dissolve the sodium p-aminobenzenesulfonate and disperse it evenly in the reaction system; Step 5: Add 0.01% to 0.05% manganese dioxide, maintain a constant temperature of 30 to 50°C, and stir to ensure that the manganese dioxide is evenly dispersed in the reaction system; Step 6: Add 1%–4% hydrogen peroxide and stir rapidly for 30–60 seconds to obtain a loose and viscous system; Step 7: Dry the loose and viscous system at 50-100 ℃ to obtain a porous, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin.

3. The preparation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to claim 2, characterized in that, The humic acid includes one or more of black humic acid, yellow humic acid, and brown humic acid.

4. The preparation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to claim 2, characterized in that, The concentration of the mixed solution of BES-Na and the metal ion soluble salt in step 3 is 0.1-1 mol / L -1 BES-Na is N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid sodium, the metal ion in the metal ion soluble salt is M, and the molar ratio of BES-Na to M in the mixed solution is 1:

1.

5. The preparation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to claim 2, characterized in that, In step 6, add 1% to 4% hydrogen peroxide and stir rapidly for 30 to 60 seconds at a stirring speed of 500 to 1000 rpm.

6. The green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin prepared by any one of claims 1 to 5, characterized in that, The superabsorbent resin has a loose pore structure and a water absorption rate of 1500g / g to 2000g / g. When using a 0.9% NaCl solution, the water absorption rate is 300g / g to 350g / g.

7. The degradation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1, disodium salt of ethylenediaminetetraacetic acid (EDTA) was mixed with water to make a 0.01 mol / L salt solution; -1 0.1 mol / L -1 salt solution. Step 2: By mass fraction, 10%–40% of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin is pulverized to the size of rice grains and mixed evenly with 60%–90% of the salt solution prepared in Step 1, wherein the sum of the mass percentages of the green, environmentally friendly, biodegradable, salt-resistant, and superabsorbent resin and the salt solution is 100%. Step 3: Adjust the acidity of the system to between pH 1 and pH 2. pH 1 is the minimum pH value at which metal ions in the soluble salt of metal ions can coordinate with disodium ethylenediaminetetraacetate (EDTA), and pH 2 is the pH value at which metal ions in the soluble salt of metal ions hydrolyze. Stir and heat to 50-80 °C, and stir at a constant temperature for 1-10 hours. The green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin is completely degraded.

8. The degradation method of the green, environmentally friendly, biodegradable, salt-resistant, superabsorbent resin according to claim 7, characterized in that, In step 1, disodium salt of ethylenediaminetetraacetic acid (EDTA) is mixed with water, heated to 50-80°C, and stirred to completely dissolve, to prepare a salt solution with a concentration of 0.01 mol / L -1 0.1 mol / L -1 .

Images