Organic wastewater adsorbent as well as preparation method and application thereof

Abstract

The invention discloses an organic wastewater adsorbent as well as a preparation method and application thereof, and belongs to the technical field of sewage treatment. Comprising the following steps: carrying out nitration reaction on styrene porous microsphere resin, and then carrying out reduction reaction to obtain amino-modified porous microsphere resin; the preparation method comprises the following steps: carrying out polymerization reaction on high-nitrogen-content amino organic small molecules and aldehyde group small molecules under the action of a basic catalyst in an adsorption polymerization manner to generate a nitrogen-doped organic porous polymer, and coating the surface of amino-modified porous microsphere resin with the nitrogen-doped organic porous polymer to obtain the organic wastewater adsorbent. The porous microsphere resin adsorbent with large adsorption capacity and high organic matter removal rate is synthesized by using the carrier advantage of styrene microsphere resin and introducing a porous heteroatom polymer on the microsphere resin. When the adsorbent is used, the adsorbent is directly added into an organic wastewater solution, and the removal rate of bisphenol A, aniline and tetracycline can reach 90% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to an organic wastewater adsorbent and a preparation method and application thereof. Background Art

[0002] In recent years, treatment technologies for industrial organic wastewater have continued to advance. Chemical oxidation is one of the more common methods for treating organic wastewater. By adding appropriate oxidants to the wastewater, small organic molecules in the wastewater are converted into carbon dioxide and water, thereby removing the organic matter. While this method offers advantages such as low cost and ease of operation, it also presents some practical challenges, such as low treatment efficiency for low-concentration organic wastewater and the use of large amounts of chemicals.

[0003] Resin adsorption is also a commonly used method for industrial wastewater treatment. By introducing specific functional groups onto the surface of a solid adsorbent, organic matter in the wastewater can be removed through electronic interactions or hydrogen bonding with the adsorbent. This method offers the advantages of simple operation and high wastewater purification, but currently, there are relatively few resins with high adsorption capacity and high organic matter treatment efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide an organic wastewater adsorbent with large adsorption capacity and high organic matter removal rate, as well as a preparation method and application thereof.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for preparing an organic wastewater adsorbent comprises the following steps: (1) subjecting the styrene-based porous microsphere resin to a nitration reaction to obtain a nitro-modified porous microsphere resin; (2) subjecting the nitro-modified porous microsphere resin to a reduction reaction to obtain an amino-modified porous microsphere resin; (3) by means of adsorption polymerization, a high nitrogen content amino organic small molecule and an aldehyde small molecule are polymerized under the action of an alkaline catalyst to generate a nitrogen-doped organic porous polymer and coat the surface of the amino-modified porous microsphere resin, thereby obtaining the organic wastewater adsorbent; The amino organic small molecule with high nitrogen content is melamine and / or phenyltriamine; the aldehyde small molecule is one or more of glyoxal, 1-formylthiophene, and terephthalaldehyde.

[0006] As a further improvement, the nitration reaction in step (1) uses a mixed solution of nitric acid and sulfuric acid.

[0007] As a further improvement, the nitration reaction temperature in step (1) is 80-100° C. and the reaction time is 8-12 h.

[0008] As a further improvement, the reducing agent used in the reduction reaction in step (2) is one of stannous chloride, sodium borohydride, and lithium aluminum tetrahydride.

[0009] As a further improvement, the reduction reaction temperature in step (2) is 40-80° C. and the time is 4-8 h.

[0010] As a further improvement, in step (3), the amount of the high nitrogen content amino organic small molecule is 5-10% of the mass of the porous microsphere resin, and the amount of the aldehyde small molecule is 5-10% of the mass of the porous microsphere resin.

[0011] As a further improvement, the alkaline catalyst in step (3) is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate, and sodium hydroxide.

[0012] As a further improvement, the polymerization reaction temperature in step (3) is 50-80°C and the reaction time is 4-8h.

[0013] The present invention provides an organic wastewater adsorbent, which is prepared by adopting the preparation method.

[0014] The present invention also provides an application of the organic wastewater adsorbent in treating organic wastewater.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses styrene-based porous microsphere resin as raw material. Since the styrene-based porous resin itself has fewer heteroatom sites, it cannot play a good adsorption role on soluble organic small molecules. Therefore, it is not efficient when directly used as an adsorbent for treating organic wastewater. In order to improve the organic adsorption capacity of this type of resin, the present invention first performs a nitration reaction on the porous resin to obtain a nitro-modified porous microsphere resin to increase the grafting sites of the resin, and then reduces the nitro-modified microsphere resin to obtain an amino-modified microsphere resin. The introduction of amino groups not only increases the heteroatom content of the resin but also provides a large number of reaction sites for subsequent polymerization reactions. Finally, by means of adsorption polymerization, high-nitrogen-content amino organic small molecules and aldehyde small molecules are generated under the action of an alkaline catalyst to generate nitrogen-doped organic porous polymer-coated styrene porous microsphere resin, which is an organic wastewater adsorbent.

[0016] Styrene-based porous microsphere resins have high mechanical strength and excellent corrosion resistance, making them an excellent adsorbent matrix. The introduction of heteroatoms can also enhance the binding capacity of organic matter and the adsorbent. This invention leverages the carrier properties of styrene-based microsphere resins by introducing porous heteroatom polymers into the microsphere resins to create a porous microsphere resin adsorbent with a large adsorption capacity and high organic matter removal rate. When added directly to an organic wastewater solution, the adsorbent can remove over 90% of bisphenol A, aniline, and tetracycline. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a structural diagram of the adsorbent in Example 1-2, where the black balls represent the resin. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0020] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0021] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0022] In some specific embodiments, the method for preparing the organic wastewater adsorbent of the present invention comprises the following steps: (1) The styrene-based porous microsphere resin is subjected to nitration reaction to obtain a nitro-modified porous microsphere resin.

[0023] In some embodiments, the styrene-based porous microsphere resin can be a polystyrene porous microsphere resin, which can be polar or medium polar, with a particle size of 0.5-5 mm. It is dried before use at a drying temperature of 80-120°C.

[0024] In some embodiments, a mixed solution of nitric acid and sulfuric acid is used for nitration. Specifically, nitric acid with a mass fraction of 25-35% and sulfuric acid with a mass fraction of 45-55% can be mixed in a volume ratio of (3.5-4.5):6 to obtain a mixed solution of nitric acid and sulfuric acid.

[0025] In some embodiments, the nitration temperature is 80-100° C., and the nitration time is 8-12 h.

[0026] (2) The nitro-modified porous microsphere resin is subjected to a reduction reaction to obtain an amino-modified porous microsphere resin.

[0027] In some embodiments, the reducing agent used during reduction is one of stannous chloride, sodium borohydride, and lithium aluminum tetrahydride. The reducing agent is used in an amount of 5-10% by weight of the porous microsphere resin. When the reducing agent is stannous chloride, the reduction is carried out in a hydrochloric acid solution, preferably with a hydrochloric acid concentration of 10%.

[0028] In some embodiments, the reduction temperature is 40-80° C., and the reduction time is 4-8 h.

[0029] (3) Through adsorption polymerization, amino organic small molecules with high nitrogen content and aldehyde small molecules are polymerized under the action of alkaline catalyst to generate nitrogen-doped organic porous polymer-coated styrene porous microsphere resin, which is an organic wastewater adsorbent.

[0030] In some embodiments, the high nitrogen content amino organic small molecule is melamine and / or phenyltriamine. The amount of the high nitrogen content amino organic small molecule is 5-10% of the mass of the porous microsphere resin.

[0031] In some embodiments, the aldehyde-based small molecule is one or more of glyoxal, 1-formylthiophene, and terephthalaldehyde. The aldehyde-based small molecule is used in an amount of 5-10% by weight of the porous microsphere resin. Compared to formaldehyde, polymerization reactions with glyoxal, 1-formylthiophene, and terephthalaldehyde can significantly increase crosslink density and adsorption capacity.

[0032] In some embodiments, the alkaline catalyst is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate, and sodium hydroxide. The amount of the alkaline catalyst used is 0.1-1% of the mass of the porous microsphere resin.

[0033] In some embodiments, the polymerization reaction temperature is 50-80° C., and the polymerization reaction time is 4-8 hours.

[0034] When used, the adsorbent of the present invention is directly poured into an organic wastewater solution and can be used to remove bisphenol A, aniline, tetracycline and the like in the organic wastewater.

[0035] When the adsorption performance of the adsorbent decreases, the adsorbent can be regenerated by backwashing with ethanol.

[0036] In the following examples, the medium-polarity styrene-based porous microsphere resin is D113 macroporous weakly acidic cation exchange resin produced by Langfang Senate Chemical Co., Ltd.

[0037] Example 1 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield an amino-modified porous microsphere resin. An ethanol solution of 50 g of melamine and 50 g of glyoxal was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield an organic wastewater treatment adsorbent.

[0038] Characterization of raw materials, intermediates and adsorbents: 1. Fourier transform infrared spectroscopy (FTIR): After nitration: nitro group appears ( ) characteristic peak ( and ).

[0039] After reduction (amination): the nitro peak disappears and the amino group appears ( ) stretching vibration peak ( ).

[0040] After polymerization: C=N bond ( ) and CO ( , the peak from the aldehyde-based polycondensation product), indicating nitrogen-doped polymer coating.

[0041] 2. Scanning electron microscopy (SEM) and specific surface area analysis (BET): Original resin: smooth surface and small pore size (BET surface area <50 m² / g).

[0042] Prepared adsorbent: A cross-linked polymer layer is formed on the surface, the pore size is enlarged (BET specific surface area > 500 m² / g), and the pore size distribution is concentrated in 2-5 nm (micropores) and 10-50 nm (mesopores).

[0043] 3. Dynamic light scattering (DLS) and thermogravimetric analysis (TGA): DLS: Particle size changes from 2 mm (macro particles) of the original resin to 2-3 mm after coating (no significant change, but increased surface roughness).

[0044] TGA: The nitrogen-doped polymer coating is stable at 300-400 ℃, with a weight loss rate of <10% (the original resin decomposes at 200 ℃).

[0045] Take 100 grams of adsorbent and pour it into 1L of 200ppm bisphenol A aqueous solution, place it on a shaker for adsorption for 1 hour, and after adsorption, the bisphenol A concentration tested by UV spectrophotometer is 18ppm, and the removal rate is 91%.

[0046] Example 2 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield an amino-modified porous microsphere resin. An ethanol solution of 50 g of melamine and 50 g of glyoxal was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield an organic wastewater treatment adsorbent.

[0047] Take 100 grams of adsorbent and pour it into 1L of aniline wastewater solution with a concentration of 200ppm, place it on a shaker for adsorption for 1 hour, and after adsorption, the aniline concentration is tested by ultraviolet spectrophotometer to be 16ppm, and the removal rate is 92%.

[0048] Example 3 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield the amino-modified porous microsphere resin. An ethanol solution of 50 g of melamine and 50 g of terephthalaldehyde was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield the organic wastewater treatment adsorbent.

[0049] Take 100 grams of adsorbent and pour it into 1L of 200ppm bisphenol A aqueous solution, place it on a shaker for adsorption for 1 hour. After adsorption, the bisphenol A concentration tested was 12ppm and the removal rate was 94%.

[0050] Example 4 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield the amino-modified porous microsphere resin. An ethanol solution of 50 g of mesitylenetriamine and 50 g of terephthalaldehyde was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield the organic wastewater treatment adsorbent.

[0051] Take 100 grams of adsorbent and pour it into 1L of aniline aqueous solution with a concentration of 200ppm, place it on a shaker for adsorption for 1 hour, and the aniline concentration after adsorption is tested to be 20ppm, with a removal rate of 90%.

[0052] Example 5 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield the amino-modified porous microsphere resin. An ethanol solution of 50 g of mesitylenetriamine and 50 g of terephthalaldehyde was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield the organic wastewater treatment adsorbent.

[0053] Take 100 grams of adsorbent and pour it into 1L of 200ppm tetracycline aqueous solution, place it on a shaker for adsorption for 1 hour. After adsorption, the tetracycline concentration tested was 16ppm and the removal rate was 92%.

[0054] Comparative Example 1 One kilogram of 2mm-diameter medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 grams of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield the amino-modified porous microsphere resin. The amino-modified resin was then used directly in adsorption experiments without polymer coating.

[0055] Take 100 grams of the amino-treated resin and pour it into 1L of 200ppm bisphenol A aqueous solution, place it on a shaker for adsorption for 1 hour, and the bisphenol A concentration after adsorption is 82ppm, with a removal rate of 59%.

[0056] Comparative Example 2 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was dried in a forced-air drying oven at 100°C for 12 hours before use. The dried resin was then poured into a mixture of 30% nitric acid and 50% sulfuric acid (4:6 by volume) and heated to 80°C for 10 hours. The nitrated porous microsphere resin was then poured into a 10% hydrochloric acid solution, followed by the slow addition of 100 g of stannous chloride. The reaction was then heated to 60°C for 8 hours to yield the amino-modified porous microsphere resin. An ethanol solution of 50 g of melamine and 50 g of formaldehyde was added, and the amino-modified porous microsphere resin was poured into the ethanol solution. 5 g of tetrabutylammonium hydroxide was then added, and the reaction was heated to 70°C for 8 hours. After the reaction, the solvent and unreacted raw materials were removed by filtration. The filter cake was washed with ethanol and vacuum-dried at 80°C for 12 hours to yield the adsorbent.

[0057] Take 100 grams of adsorbent and pour it into 1L of 200ppm bisphenol A aqueous solution, place it on a shaker for adsorption for 1 hour. After adsorption, the bisphenol A concentration tested was 64ppm and the removal rate was 68%.

[0058] Comparative Example 3 1 kg of 2 mm medium-polarity styrene-based porous microsphere resin was placed in a forced air drying oven at 100°C for 12 hours for drying and then directly subjected to polymer coating without undergoing nitration or amination reactions. An ethanol solution of 50 g of melamine and 50 g of terephthalaldehyde was prepared. The unmodified porous microsphere resin was poured into the ethanol solution and 5 g of tetrabutylammonium hydroxide was added. The temperature was raised to 70°C for reaction for 8 hours. After the reaction, the solvent and unreacted raw materials were filtered to remove the solvent and unreacted raw materials. The filter cake was washed with ethanol and vacuum dried at 80°C for 12 hours to obtain the adsorbent.

[0059] Take 100 grams of adsorbent and pour it into 1L of 200ppm bisphenol A aqueous solution, place it on a shaker for adsorption for 1 hour. After adsorption, the bisphenol A concentration tested was 92ppm and the removal rate was 54%.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing an organic wastewater adsorbent, characterized in that: The following steps are included: (1) subjecting the styrene-based porous microsphere resin to a nitration reaction to obtain a nitro-modified porous microsphere resin; (2) subjecting the nitro-modified porous microsphere resin to a reduction reaction to obtain an amino-modified porous microsphere resin; (3) by means of adsorption polymerization, a high nitrogen content amino organic small molecule and an aldehyde small molecule are polymerized under the action of an alkaline catalyst to generate a nitrogen-doped organic porous polymer and coat the surface of the amino-modified porous microsphere resin, thereby obtaining the organic wastewater adsorbent; The amino organic small molecule with high nitrogen content is melamine and / or phenyltriamine; the aldehyde small molecule is one or more of glyoxal, 1-formylthiophene, and terephthalaldehyde.

2. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The nitration reaction in step (1) uses a mixed solution of nitric acid and sulfuric acid.

3. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The nitration reaction temperature in step (1) is 80-100°C and the reaction time is 8-12 hours.

4. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The reducing agent used in the reduction reaction of step (2) is one of stannous chloride, sodium borohydride, and lithium aluminum tetrahydride.

5. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The reduction reaction temperature in step (2) is 40-80°C and the time is 4-8h.

6. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: In step (3), the amount of the high nitrogen content amino organic small molecule is 5-10% of the mass of the porous microsphere resin, and the amount of the aldehyde small molecule is 5-10% of the mass of the porous microsphere resin.

7. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The alkaline catalyst in step (3) is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate, and sodium hydroxide.

8. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The polymerization reaction temperature in step (3) is 50-80°C and the reaction time is 4-8h.

9. An organic wastewater adsorbent, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the organic wastewater adsorbent according to claim 9 in treating organic wastewater.

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