Preparation method of a porous adsorption resin and application thereof in sewage treatment

Abstract

The present invention relates to the technical field of sewage treatment, and discloses a preparation method of a porous adsorption resin and its application in sewage treatment. In the present invention, a quaternization cross-linking reaction occurs between the tertiary amine groups of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base)-based polyethylene glycol and a polyacrylonitrile resin, and the polyacrylonitrile-based porous adsorption resin with a three-dimensional porous structure is cross-linked. It has a larger specific surface area and more adsorption sites. At the same time, it contains a large number of o-hydroxy Schiff base structures and hydroxyl groups, has a strong coordination effect and complexation adsorption performance for lead ions, and contains quaternary ammonium salt cations and hydroxyl groups, which form electrostatic attraction and hydrogen bond interactions with congo red, improving the adsorption performance of the polyacrylonitrile resin for dyes such as congo red.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly to a preparation method of a porous adsorption resin and its application in sewage treatment. Background Art

[0002] The development of high-performance adsorbents is a research hotspot, mainly including porous activated carbon, molecular sieves, fiber membranes, polymer resins, etc. Among them, polyacrylonitrile resin has good mechanical properties, excellent solvent resistance and corrosion resistance, and has broad application prospects in the field of sewage treatment.

[0003] Introducing groups such as carboxyl, amidoxime, and hydroxyl into polyacrylonitrile resin can improve its adsorption performance. Chinese Patent CN106467594B discloses the preparation of a polyacrylonitrile-polyvinyltetrazole chelating resin. By reacting polyacrylonitrile, sodium azide, and ammonium chloride, and then making a spherical chelating resin under the action of an oil-in-water dispersion aid, it has extremely high adsorption performance for metal ions. However, this chelating resin does not show an adsorption effect on dye pollutants such as congo red. Summary of the Invention

[0004] The present invention solves the problem that the polyacrylonitrile resin has poor adsorption performance for metal ions and dye pollutants.

[0005] The technical solution of the present invention is: A preparation method of a porous adsorption resin:

[0006] Step A: Add dimethyl sulfoxide, acrylonitrile, and acrylate tertiary amine monomer to a reaction vessel, stir, and then dropwise add azobisisobutyronitrile for polymerization reaction. After cooling, add water to precipitate, filter, wash the precipitate with ethanol, and dry to obtain tertiary amine polyacrylonitrile resin.

[0007] Step B: Add N,N-dimethylformamide, tertiary amine polyacrylonitrile, and bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol to a reaction vessel for quaternization reaction. After filtration, wash with water and ethanol, and dry to obtain a porous adsorption resin.

[0008] Further, the temperature of the polymerization reaction in Step A is 60-75°C, and the reaction time is 18-24h.

[0009] Further, the dosage of acrylonitrile in Step A is 100 parts by weight, the acrylate tertiary amine monomer is 5-20 parts by weight, and azobisisobutyronitrile is 1.1-1.4 parts by weight.

[0010] Further, the temperature of the quaternization reaction in Step B is 110-130°C, and the reaction time is 24-36h.

[0011] Further, in step B, the mass ratio of tertiary amino group polyacrylonitrile to polyethylene glycol bis(2-hydroxy-5-chloromethyl benzaldehyde schiff base) is 100:(20-80).

[0012] Further, the preparation method of acrylate tertiary amine monomer is as follows: Add glycidyl methacrylate (100 parts by weight) and N-methyl-2-hydroxyethylamine (53-58 parts by weight) into tetrahydrofuran in a reaction vessel, heat to 40-45 °C, react for 4-5 h, remove low-boiling substances by vacuum distillation, and dry to obtain acrylate tertiary amine monomer. The reaction formula is:

[0013]

[0014] Further, the preparation method of polyethylene glycol bis(2-hydroxy-5-chloromethyl benzaldehyde schiff base) is as follows: Add ethanol, bisamino polyethylene glycol (100 parts by weight), and 5-chloromethyl salicylaldehyde (17.5-19%) into a reaction vessel, heat to 45-50 °C, react for 1-1.5 h, rotary evaporate, wash with petroleum ether, and dry to obtain polyethylene glycol bis(2-hydroxy-5-chloromethyl benzaldehyde schiff base). The reaction formula is:

[0015]

[0016] Further, the porous adsorption resin is applied to the treatment of wastewater containing metal and dye pollutants.

[0017] The technical effects of the present invention: Copolymerize acrylonitrile and acrylate tertiary amine monomer to obtain tertiary amino group polyacrylonitrile resin containing hydroxyl and tertiary amine groups; React bisamino polyethylene glycol and 5-chloromethyl salicylaldehyde to obtain polyethylene glycol bis(2-hydroxy-5-chloromethyl benzaldehyde schiff base), and then the double-terminal chloromethyl groups thereof react with the tertiary amine groups of polyacrylonitrile resin to undergo quaternization cross-linking reaction to cross-link and obtain polyacrylonitrile-based porous adsorption resin with a three-dimensional porous structure. It has a larger specific surface area and more adsorption sites, and at the same time contains a large number of o-hydroxy schiff base structures and hydroxyl groups, which have a strong coordination effect and complex adsorption performance on lead ions, significantly improving the adsorption capacity of polyacrylonitrile resin for metal ions such as lead.

[0018] The porous adsorption resin of the present invention contains quaternary ammonium salt cations, which can form electrostatic attraction with the anions of congo red, and at the same time, the hydroxyl groups of the porous adsorption resin form hydrogen bond interaction with the amino groups of congo red, significantly improving the adsorption performance of polyacrylonitrile resin for dyes such as congo red. Specific embodiments

[0019] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to related embodiments. The preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0020] Diamino polyethylene glycol, molecular weight 2000, Chongqing Yusai Medical Technology Co., Ltd.

[0021] Example 1:

[0022] Step (1): Add 200 mL of ethanol, 20 g of diamino polyethylene glycol, and 3.5 g of 2-hydroxy-5-chloromethylbenzaldehyde to the reaction vessel, heat to 45 °C, react for 1.5 h, perform rotary evaporation, wash with petroleum ether, and dry to obtain bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol.

[0023] Step (2): Add 12 mL of tetrahydrofuran, 3 g of glycidyl methacrylate, and 1.74 g of N-methyl-2-hydroxyethylamine to the reaction vessel, heat to 40 °C, react for 4 h, distill off low-boiling substances under reduced pressure, and dry to obtain acrylate tertiary amine monomer.

[0024] Step (3): Add 250 mL of dimethyl sulfoxide, 50 g of acrylonitrile, and 2.5 g of acrylate tertiary amine monomer to the reaction vessel, stir and then dropwise add 0.11 g of azobisisobutyronitrile, raise the temperature to 70 °C, carry out polymerization reaction for 18 h, cool and then add water to precipitate, filter and wash the precipitate with ethanol, and dry to obtain tertiary amine group polyacrylonitrile resin.

[0025] Step (4): Add 600 mL of N,N-dimethylformamide, 60 g of tertiary amine group polyacrylonitrile, and 12 g of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol to the reaction vessel, raise the temperature to 120 °C, carry out quaternization reaction for 24 h, filter and wash with water and ethanol, and dry to obtain porous adsorption resin.

[0026] Example 2:

[0027] Step (1): Add 250 mL of ethanol, 20 g of diamino polyethylene glycol, and 3.8 g of 2-hydroxy-5-chloromethylbenzaldehyde to the reaction vessel, heat to 50 °C, react for 1 h, perform rotary evaporation, wash with petroleum ether, and dry to obtain bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol.

[0028] Step (2): Add 10 mL of tetrahydrofuran, 3 g of glycidyl methacrylate, and 1.59 g of N-methyl-2-hydroxyethylamine into the reaction vessel, heat to 45 °C, react for 5 h, remove low-boiling substances by vacuum distillation, and dry to obtain the acrylate tertiary amine monomer.

[0029] Step (3): Add 300 mL of dimethyl sulfoxide, 50 g of acrylonitrile, and 6.2 g of the acrylate tertiary amine monomer into the reaction vessel. After stirring, add 0.13 g of azobisisobutyronitrile dropwise, raise the temperature to 60 °C, carry out the polymerization reaction for 24 h, add water to precipitate after cooling, filter, wash the precipitate with ethanol, and dry to obtain the tertiary amine group polyacrylonitrile resin.

[0030] Step (4): Add 700 mL of N,N-dimethylformamide, 60 g of the tertiary amine group polyacrylonitrile, and 30 g of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol into the reaction vessel, raise the temperature to 110 °C, carry out the quaternization reaction for 36 h, filter, wash with water and ethanol, and dry to obtain the porous adsorption resin.

[0031] Example 3:

[0032] Step (1): Add 300 mL of dimethyl sulfoxide, 50 g of acrylonitrile, and 10 g of the acrylate tertiary amine monomer (prepared in the same way as in Example 1) into the reaction vessel. After stirring, add 0.14 g of azobisisobutyronitrile dropwise, raise the temperature to 75 °C, carry out the polymerization reaction for 18 h, add water to precipitate after cooling, filter, wash the precipitate with ethanol, and dry to obtain the tertiary amine group polyacrylonitrile resin.

[0033] Step (2): Add 700 mL of N,N-dimethylformamide, 60 g of the tertiary amine group polyacrylonitrile, and 48 g of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol (prepared in the same way as in Example 1) into the reaction vessel, raise the temperature to 120 °C, carry out the quaternization reaction for 36 h, filter, wash with water and ethanol, and dry to obtain the porous adsorption resin.

[0034] Comparative Example 1 uses the tertiary amine group polyacrylonitrile resin as the adsorption resin

[0035] Comparative Example 2:

[0036] Step (1): Add 250 mL of dimethyl sulfoxide, 50 g of acrylonitrile, and 2.5 g of dimethylaminoethyl methacrylate After stirring, add 0.11 g of azobisisobutyronitrile dropwise, raise the temperature to 70 °C, carry out the polymerization reaction for 18 h, add water to precipitate after cooling, filter, wash the precipitate with ethanol, and dry to obtain the tertiary amine group polyacrylonitrile resin.

[0037] Step (2): Add 600 mL of N,N-dimethylformamide, 60 g of tertiary amine-based polyacrylonitrile, and 12 g of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol (prepared in the same manner as in Example 1) into the reaction vessel. Heat up to 120 °C and carry out the quaternization reaction for 24 h. After filtration, wash with water and ethanol, and then dry to obtain the porous adsorption resin.

[0038] Comparative Example 3:

[0039] Step (1): Add 250 mL of dimethyl sulfoxide, 50 g of acrylonitrile, and 2.5 g of 2-hydroxyethyl methacrylate into the reaction vessel. Stir and then dropwise add 0.11 g of azobisisobutyronitrile. Heat up to 70 °C and carry out the polymerization reaction for 18 h. After cooling, add water to precipitate, filter, wash the precipitate with ethanol, and then dry to obtain the hydroxyethyl polyacrylonitrile resin.

[0040] Step (2): Add 600 mL of N,N-dimethylformamide, 60 g of hydroxyethyl polyacrylonitrile resin, and 12 g of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol (prepared in the same manner as in Example 1) into the reaction vessel. Heat up to 120 °C and carry out the quaternization reaction for 24 h. After filtration, wash with water and ethanol, and then dry to obtain the hydroxyethyl polyacrylonitrile resin.

[0041] Comparative Example 4:

[0042] Step (1): Add 200 mL of tetrahydrofuran, 20 g of diaminopolyethylene glycol, and 4.5 g of 4-chloromethylbenzoyl chloride 2.1 g of triethylamine into the reaction vessel. Heat up to 45 °C and carry out the amidation reaction for 1.5 h. Rotate and evaporate, wash with petroleum ether, and then dry to obtain the dichloromethyl polyethylene glycol. The structural formula is:

[0043] Step (2): Add 600 mL of N,N-dimethylformamide, 60 g of tertiary amine-based polyacrylonitrile (prepared in the same manner as in Example 1), and 12 g of dichloromethyl polyethylene glycol into the reaction vessel. Heat up to 120 °C and carry out the quaternization reaction for 24 h. After filtration, wash with water and ethanol, and then dry to obtain the porous adsorption resin.

[0044] Prepare a 500 mL lead ion Pb 2+ standard solution with a concentration of 60 mg / L. Add 200 - 500 mg of the porous adsorption resin, stir and adsorb at 25 °C for 4 h. Take the supernatant and measure the concentration of the solution by an atomic absorption spectrophotometer, and calculate the removal rate Q. Q = (C0 - C) / C0 × 100%. C0 is the initial concentration of the solution, and C is the concentration of the solution after adsorption.

[0045] Table 1

[0046]

[0047] As can be seen from the above table, the porous adsorption resins in Examples 1 - 3 have a high removal rate for Pb 2+ lead ions, mainly because the porous adsorption resin contains a rich pore structure, a larger specific surface area, more adsorption sites, and at the same time contains a large number of o - hydroxy Schiff base structures and hydroxyl groups, which have a strong coordination effect and complex adsorption performance on lead ions, significantly improving the adsorption ability of the polyacrylonitrile resin for metal ions such as lead.

[0048] Compared with Example 1, in Comparative Example 1, the quaternary ammonium cross - linking reaction of bis(2 - hydroxy - 5 - chloromethylbenzaldehyde Schiff base) - based polyethylene glycol with tertiary amine - based polyacrylonitrile resin was not utilized. The tertiary amine - based polyacrylonitrile resin did not cross - link to form a porous structure, had a small specific surface area, few adsorption sites, and did not contain an o - hydroxy Schiff base structure, resulting in a low coordination effect and complex adsorption performance on lead ions, and thus a very low removal rate.

[0049] In Comparative Example 2, acrylonitrile and dimethylaminoethyl methacrylate (without hydroxyl group) were copolymerized to obtain tertiary amine - based polyacrylonitrile and the porous adsorption resin had very little hydroxyl content, resulting in a lower coordination effect and complex adsorption performance on lead ions than in Example 1, and thus a lower removal rate than in Example 1.

[0050] In Comparative Example 3, acrylonitrile and 2 - hydroxyethyl methacrylate (without tertiary amine group) were copolymerized to obtain hydroxyethyl polyacrylonitrile resin which did not contain a tertiary amine group and could not undergo a quaternary ammonium cross - linking reaction with bis(2 - hydroxy - 5 - chloromethylbenzaldehyde Schiff base) - based polyethylene glycol, did not cross - link to form a porous structure, had fewer adsorption sites, and after washing, bis(2 - hydroxy - 5 - chloromethylbenzaldehyde Schiff base) - based polyethylene glycol was washed away. The hydroxyethyl polyacrylonitrile resin did not contain an o - hydroxy Schiff base structure, resulting in a lower coordination effect and complex adsorption performance on lead ions than in Example 1, and thus a lower removal rate than in Example 1.

[0051] The dichloromethyl polyethylene glycol in Comparative Example 4 and the prepared porous adsorption resin did not contain an o - hydroxy Schiff base structure, resulting in a lower coordination effect and complex adsorption performance on lead ions than in Example 1, and thus a lower removal rate than in Example 1. However, the double - end chlorine atoms of dichloromethyl polyethylene glycol underwent a quaternary ammonium cross - linking reaction with tertiary amine - based polyacrylonitrile, cross - linking to form a three - dimensional porous structure, which was beneficial to increasing the specific surface area and adsorption sites, making the lead ion removal rate higher than that in Comparative Example 1 and Comparative Example 3.

[0052] Prepare 500 mL of methyl orange solution with a concentration of 100 mg / L, add 300 - 700 mg of porous adsorption resin, stir and adsorb at 25 °C for 2 h, take the supernatant, and test the concentration of the solution by ultraviolet-visible absorption spectrophotometer to calculate the removal rate Q. Q = (C0 - C) / C0 × 100%. C0 is the initial concentration of the solution, and C is the concentration of the solution after adsorption.

[0053] Table 2

[0054]

[0055] As can be seen from the above table, the porous adsorption resins in Examples 1 - 3 have a high removal rate for congo red. This is mainly because the porous adsorption resin contains quaternary ammonium salt cations, which can form electrostatic attraction with the anions of congo red. At the same time, the hydroxyl groups of the porous adsorption resin form hydrogen bond interactions with the amino groups of congo red, significantly improving the adsorption performance of the polyacrylonitrile resin for dyes such as congo red.

[0056] The polyacrylonitrile resins in Comparative Example 1 and Comparative Example 3 do not contain porous structures, have few adsorption sites, and do not contain quaternary ammonium salt cation groups, resulting in weak adsorption forces with congo red and poor adsorption performance and removal rates.

[0057] Compared with Example 1, the porous adsorption resin in Comparative Example 2 has a low hydroxyl content and lower hydrogen bond interaction with congo red, resulting in lower adsorption performance and removal rate than Example 1.

[0058] The porous adsorption resin in Comparative Example 4 also contains a large amount of quaternary ammonium salt cations and hydroxyl groups, which can form electrostatic attraction and hydrogen bond interactions with congo red, and has excellent adsorption performance and removal rate.

Claims

1. A method for preparing a porous adsorption resin, characterized in that, The preparation method is as follows: Step A: Add dimethyl sulfoxide, acrylonitrile, and acrylate tertiary amine monomer into a reaction vessel. After stirring, add azobisisobutyronitrile dropwise and carry out a polymerization reaction. After cooling, add water to precipitate, filter, wash the precipitate, and dry to obtain a tertiary amine group polyacrylonitrile resin; Step B: Add N,N-dimethylformamide, tertiary amine group polyacrylonitrile, and bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol into a reaction vessel to carry out a quaternization reaction. After filtering, wash and dry to obtain a porous adsorption resin; The structural formula of the acrylate tertiary amine monomer is as follows: In Step A, the dosage of acrylonitrile is 100 parts by weight, the acrylate tertiary amine monomer is 5-20 parts by weight, and azobisisobutyronitrile is 1.1-1.4 parts by weight; In Step B, the mass ratio of tertiary amine group polyacrylonitrile to bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol is 100:(20-80).

2. The preparation method of the porous adsorption resin according to claim 1, characterized in that, In Step A, the temperature of the polymerization reaction is 60-75°C, and the reaction time is 18-24 h.

3. The preparation method of the porous adsorption resin according to claim 1, characterized in that, The preparation method of the acrylate tertiary amine monomer is as follows: Add tetrahydrofuran, glycidyl methacrylate, and N-methyl-2-hydroxyethylamine into a reaction vessel, heat to 40-45°C, react for 4-5 h, distill off low-boiling substances under reduced pressure, and dry to obtain the acrylate tertiary amine monomer.

4. The preparation method of the porous adsorption resin according to claim 3, characterized in that, The dosage of glycidyl methacrylate is 100 parts by weight, and the dosage of N-methyl-2-hydroxyethylamine is 53-58 parts by weight.

5. The preparation method of the porous adsorption resin according to claim 1, wherein, In Step B, the temperature of the quaternization reaction is 110-130°C, and the reaction time is 24-36 h.

6. The preparation method of the porous adsorption resin according to claim 1, characterized in that, The preparation method of bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol is as follows: Add ethanol, diamino polyethylene glycol, and 5-chloromethyl salicylaldehyde into a reaction vessel, heat to 45-50°C, react for 1-1.5 h, perform rotary evaporation, wash, and dry to obtain bis(2-hydroxy-5-chloromethylbenzaldehyde Schiff base) polyethylene glycol.

7. The preparation method of the porous adsorption resin according to claim 6, wherein, The dosage of diamino polyethylene glycol is 100 parts by weight, and the dosage of 5-chloromethyl salicylaldehyde is 17.5-19%.

8. Application of the porous adsorption resin obtained by the preparation method according to any one of claims 1-7 in sewage treatment.

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