CN110368911A - A kind of preparation method of pyridine functional chitosan absorbent - Google Patents

Abstract

The invention discloses a preparation method of a pyridine functionalized chitosan adsorbent, comprising the following steps: S1: mixing polyethyleneimine with a mass concentration of 5-100 g/L and 2-2-2 with a mass concentration of 2.5-100 g/L Chloromethylpyridine hydrochloride and sodium carbonate with a mass concentration of 10-100 g/L are dissolved in an aqueous solution of ethanol with a volume concentration of 5-80%. The pyridine functionalized chitosan adsorbent of the present invention can be applied to fields such as the simultaneous removal of heavy metals and antibiotics in livestock and poultry wastewater under a wide pH range, and solves the problem of small adsorption capacity and slow adsorption rate when synergistically adsorbing heavy metals and antibiotics. Engineering requires a large amount of resin, long operating time, small or even no adsorption under strong acid conditions and other technical problems, and the economic and environmental benefits are remarkable.

Description

A kind of preparation method of pyridine functionalized chitosan adsorbent

technical field

The invention relates to the field of modified resin synthesis, in particular to a preparation method of a pyridine functionalized chitosan adsorbent.

Background technique

In order to promote animal growth, improve feed efficiency, and treat and control diseases, veterinary antibiotics and trace heavy metal elements have been widely used in intensive livestock and poultry farming. Heavy metals often mix and coexist in soil and water, which pose a huge potential hazard to the environment and human health. The common treatment method for livestock and poultry wastewater is biochemical method, but the heavy metals and antibiotics are difficult to remove. The removal methods for complex pollutants of heavy metals and antibiotics at home and abroad include membrane filtration method, catalytic redox method, ion exchange and adsorption method, phytoremediation technology or combined process. The removal of pollutants in water based on the principle of physical and chemical adsorption has the advantages of simplicity, speed, and greenness. It is the preferred technology for the removal of heavy metals and antibiotics in aquaculture wastewater. Among them, the adsorption method based on high-efficiency biomass adsorbent has become the preferred process because of its advantages of simple operation, high efficiency, reliability, recyclability and environmental friendliness.

Biomass adsorbents have green characteristics that traditional polymer materials do not have, such as biodegradability, raw material renewability, and environmental friendliness. They mainly enrich heavy metal ions and organic substances in water bodies through physical-chemical methods. The purpose of removing heavy metal ions and organic matter in water respectively. For example, the application number is CN201811142664.6, and the patent application document published on December 14, 2018 discloses a preparation method of a chelating adsorbent. The preparation method of the adsorbent is as follows: dissolving chitosan in acidic solution, and then mixed with an organic solvent; add ethylenediaminetetraacetic acid dianhydride graft monomer (EDTAD), and carry out graft polymerization reaction at 60-80°C under the protection of an inert gas; after the reaction, wash and dry, A chitosan graft was obtained. The chelating adsorbent of the invention has good adsorption properties, and the EDTAD grafted on the chitosan provides nodes, especially capable of firmly chelating calcium ions. The adsorbent after adsorption can recover metal ions by elution method, and can be used continuously; it has good stability inside the tailings dam. The application number is CN201810159080.3, and the patent application document published on July 31, 2018 discloses a modified sodium alginate adsorption material and its preparation method for the adsorption of tetracycline antibiotics. The preparation method steps of the adsorption material Step 1: Mix and stir sodium alginate and solvent according to the mass volume ratio of 1-3:97-99 to make sodium alginate fully swell, degas and degas it by ultrasonic to obtain sodium alginate sol; step 2 1. Drop the sodium alginate sol into the metal salt solution with a mass concentration of 1-10wt% at a uniform speed, stir, cross-link for 2-24 hours, filter, and dry to obtain the modified sodium alginate used for the adsorption of tetracycline antibiotics Adsorbent material. The raw material of the adsorbent obtained by the invention is cheap and easy to obtain, the preparation process of the adsorbent is simple, the removal efficiency of tetracycline antibiotics is high, the adsorbent is biodegradable after use, can be regenerated, no secondary pollution occurs, and has good application prospects. Literature Zhao, G., Huang, X., Tang, Z. et al. Polymer-Based Nanocomposites for Heavy Metal IonsRemoval from Aqueous Solution: A Review[J]. Polym. Chem., 2018, 9(26): 3562- 3582. The method of biomass adsorbent disclosed in the above patents or documents can only adsorb single heavy metals or antibiotics, and cannot simultaneously remove heavy metals and antibiotics, and solve the problem of selective and synergistic adsorption of heavy metals and antibiotics, which makes it possible to treat complex pollutants in water bodies. Heavy metals or antibiotics are restricted.

In view of the low adsorption capacity of existing biomass adsorbents for heavy metals in high-acid and high-salt environments, and the inability to simultaneously remove heavy metals and antibiotics, to solve the problem of selective and synergistic adsorption of heavy metals and antibiotics, the present invention provides a pyridine functionalized chitosan Sorbent preparation method.

Contents of the invention

Based on the technical problems existing in the background technology, the present invention proposes a preparation method of a pyridine functionalized chitosan adsorbent.

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present invention comprises the following steps:

S1: Dissolve polyethyleneimine with a mass concentration of 5-100 g/L, 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and sodium carbonate with a mass concentration of 10-100 g/L in volume In the aqueous solution of ethanol with a concentration of 5-80%, the dissolving temperature of the aqueous ethanol solution is set at 20-90°C, and the dissolving time of the aqueous ethanol solution is set at 2-10 h, and at the same time, it is stirred by magnetic force in an oil bath at 85°C until Stir evenly, and then use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools to 30°C, and then cools at a rate of 0.3-0.5°C/min until it cools down to to room temperature, then use centrifugal equipment and filter sieves to perform centrifugation and filtration in sequence, and finally undergo rotary evaporation for 1-60 minutes to obtain the oil phase;

S2: Dissolving chitosan powder with a mass concentration of 2-50 g/L in an acetic acid solution with a volume concentration of 1-8%, the dissolution temperature of the acetic acid solution is set to 20-80 ° C, and the dissolution time of the acetic acid solution is set to 20-90 min, at the same time, use the stirring equipment to stir until it is evenly stirred, and then the filter equipment uses multiple screens from top to bottom to perform multi-stage filtration, and the meshes of the multiple screens from top to bottom are gradually reduced. Finally obtain chitosan mother liquor;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 1-60 h , in the process of the reaction, use stirring equipment to stir evenly, and use epichlorohydrin with a volume concentration of 0.4-15% for initial cross-linking. The coupling time is set to 1-20 h to obtain the mixed mother liquor;

S4: Add the mixed mother liquor obtained in S3 into the coagulation bath, which is a mixed solution of one or more of sodium sulfate, sodium hydroxide, sodium tripolyphosphate and sodium pyrophosphate dissolved in it, and the sulfuric acid in the coagulation bath The mass concentrations of sodium and sodium hydroxide are 10-200 g/L and 10-200 g/L respectively, and composite microspheres are obtained through precipitation and solidification;

S5: Extract the 2-40 g/L composite microspheres in step S4 through a Soxhlet extractor for 2-10 h to remove the porogen remaining in the resin channels, wash with ethanol and distilled water in sequence, and dehydrate Finally, take out the composite microspheres and add them to an aqueous solution of sodium hydroxide with a pH of 10-14, and use epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking. The crosslinking temperature of epichlorohydrin crosslinking is Set it to 20-80°C, and set the cross-linking time of epichlorohydrin cross-linking to 1-10 h to prepare cross-linked microspheres, wash the cross-linked microspheres with distilled water until neutral, dehydrate and store them for later use to obtain pyridine Functionalized chitosan adsorbent.

The beneficial effects of the present invention are:

(1) The material cost of the resin prepared by the present invention is low, the modified functional group has a stable spatial structure, and multiple nitrogen atoms on the pyridyl group and the amine group can coordinate and chelate heavy metals and antibiotics at the same time;

(2) The chelating resin provided by the present invention significantly improves the adsorption capacity for heavy metals and antibiotics due to the increase in the adsorption sites of nitrogen-containing functional groups, and solves the problem of removing heavy metals or antibiotics in livestock and poultry wastewater, with small adsorption capacity and high adsorption rate. slow problem;

(3) The chelating resin provided by the present invention can realize the selective removal and synchronous recovery of heavy metals and antibiotics by changing the adsorption pH range, salt resistance characteristics, adsorption sites and spatial structure of heavy metal ions and antibiotics. It has broad application prospects in the selective and coordinated control of complex pollutants in livestock and poultry breeding wastewater.

Detailed ways

The present invention will be further explained below in conjunction with specific embodiments.

Example 1

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 0.1 g of polyethyleneimine with a mass concentration of 5-100 g/L, 0.05 g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 0.2 g of a mass concentration of 10-100 g/L Dissolve g/L sodium carbonate in an aqueous solution of 1 ml ethanol and 5 ml distilled water, set the dissolving temperature to 85 °C, and set the dissolving time to 2 h, and at the same time use magnetic force in an 85 °C oil bath to stir until it is evenly stirred, then Use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools down to 30°C. The cooling device then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then Use a centrifugal device and a filter sieve to perform centrifugation and filtration in sequence, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 0.06 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 0.3 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 20 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 1 h. During the reaction process, use a stirring device to stir evenly, and use 0.144ml of epichlorohydrin with a volume concentration of 0.4-15% for initial crosslinking. Set to 1 h to obtain the mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 3 g of anhydrous sodium sulfate and 3 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 2 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water three times in turn, and after dehydration, take out 0.2 g of the composite microspheres. Add the ball to 100ml of sodium hydroxide aqueous solution with a pH value of 10, and use 0.01 ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking, and the crosslinking temperature for epichlorohydrin crosslinking is set to 20 ℃, and the cross-linking time of epichlorohydrin cross-linking was set as 1 h to prepare cross-linked microspheres, which were washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent a.

Example 2

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 0.2g of polyethyleneimine with a mass concentration of 5-100 g/L, 0.05g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 0.2g of a mass concentration of 10-100 Dissolve g/L sodium carbonate in an aqueous solution of 1 ml ethanol and 5 ml distilled water, set the dissolving temperature to 85 °C, and set the dissolving time to 2 h, and at the same time use magnetic force in an 85 °C oil bath to stir until it is evenly stirred, then Use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools down to 30°C. The cooling device then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then Use a centrifugal device and a filter sieve to perform centrifugation and filtration in sequence, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 0.06 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 0.3 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 20 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 1 h. During the reaction process, use a stirring device to stir evenly, and use 0.144ml of epichlorohydrin with a volume concentration of 0.4-15% for initial crosslinking. Set to 1 h to obtain the mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 3 g of anhydrous sodium sulfate and 3 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 2 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water three times in turn, and after dehydration, take out 0.2 g of the composite microspheres. Add the ball to 100ml of sodium hydroxide aqueous solution with a pH value of 10, and use 0.01 ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking, and the crosslinking temperature for epichlorohydrin crosslinking is set to 20 ℃, and the cross-linking time of epichlorohydrin cross-linking was set as 1 h to prepare cross-linked microspheres, which were washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent b.

Example 3

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 0.7g of polyethyleneimine with a mass concentration of 5-100 g/L, 0.25g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 0.3231g of a mass concentration of 10-100 g/L Dissolve g/L sodium carbonate in an aqueous solution of 15 ml ethanol and 5 ml distilled water, set the dissolving temperature to 85 °C, and set the dissolving time to 2 h, and at the same time use magnetic force in an 85 °C oil bath to stir until it is evenly stirred, then Use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools down to 30°C. The cooling device then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then Use a centrifugal device and a filter sieve to perform centrifugation and filtration in sequence, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 0.5 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 0.6 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 30 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 2 h. During the reaction process, use a stirring device to stir evenly, and use 0.23ml of epichlorohydrin with a volume concentration of 0.4-15% for initial cross-linking. Set to 2h to obtain mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 13 g of anhydrous sodium sulfate and 16 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 4 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water for 3 times in turn, and take out 2 g of composite microspheres after dehydration Add 100ml of sodium hydroxide aqueous solution with a pH value of 13, use 0.3 ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking, and set the crosslinking temperature of epichlorohydrin to 60°C , and the cross-linking time of epichlorohydrin cross-linking was set to 2 h to obtain cross-linked microspheres, which were then washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent C .

Example 4

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 0.7g of polyethyleneimine with a mass concentration of 5-100 g/L, 0.25g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 0.3231g of a mass concentration of 10-100 g/L Dissolve g/L sodium carbonate in an aqueous solution of 15 ml ethanol and 5 ml distilled water, set the dissolving temperature to 85 °C, and set the dissolving time to 2 h, and at the same time use magnetic force in an 85 °C oil bath to stir until it is evenly stirred, then Use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools down to 30°C. The cooling device then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then Use a centrifugal device and a filter sieve to perform centrifugation and filtration in sequence, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 0.9 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 0.6 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 30 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 2 h. During the reaction process, use a stirring device to stir evenly, and use 0.23ml of epichlorohydrin with a volume concentration of 0.4-15% for initial cross-linking. Set to 2h to obtain mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 13 g of anhydrous sodium sulfate and 16 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 4 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water for 3 times in turn, and take out 2 g of composite microspheres after dehydration Add 100ml of sodium hydroxide aqueous solution with a pH value of 13, use 0.3 ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking, and set the crosslinking temperature of epichlorohydrin to 60°C , and the cross-linking time of epichlorohydrin cross-linking was set to 2 h, and the cross-linked microspheres were obtained, and the cross-linked microspheres were washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent D .

Example 5

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 0.7g of polyethyleneimine with a mass concentration of 5-100 g/L, 0.5g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 0.3231g of a mass concentration of 10-100 Dissolve g/L sodium carbonate in an aqueous solution of 15 ml ethanol and 5 ml distilled water, set the dissolving temperature to 85 °C, and set the dissolving time to 2 h, and at the same time use magnetic force in an 85 °C oil bath to stir until it is evenly stirred, then Use the cooling device for cooling operation. The cooling device first cools at a rate of 3-5°C/min until it cools down to 30°C. The cooling device then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then Use a centrifugal device and a filter sieve to perform centrifugation and filtration in sequence, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 0.9 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 0.6 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 30 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 2 h. During the reaction process, use a stirring device to stir evenly, and use 0.23ml of epichlorohydrin with a volume concentration of 0.4-15% for initial cross-linking. Set to 2h to obtain mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 13 g of anhydrous sodium sulfate and 16 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 4 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water for 3 times in turn, and take out 2 g of composite microspheres after dehydration Add 100ml of sodium hydroxide aqueous solution with a pH value of 13, use 0.3 ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking, and set the crosslinking temperature of epichlorohydrin to 60°C , and the cross-linking time of epichlorohydrin cross-linking was set to 2 h to obtain cross-linked microspheres, which were washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent E .

Example 6

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 2 g of polyethyleneimine with a mass concentration of 5-100 g/L, 2 g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 2 g of a mass concentration of 10-100 g/L Sodium carbonate was dissolved in an aqueous solution of 15 ml ethanol and 5 ml distilled water, the dissolution temperature was set at 85°C, and the dissolution time was set at 2 h, and at the same time, it was stirred by magnetic force in an oil bath at 85°C until it was evenly stirred, and then the cooling device was used to For cooling operation, the cooling device first cools at a rate of 3-5°C/min until it cools to 30°C, and then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then uses a centrifugal device Centrifuge and filter in turn with a filter sieve, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 1.5 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 2.4 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 90 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, and the reaction time between the oil phase and the chitosan mother liquor is set to 8h. During the process, the stirring equipment was used to stir evenly, and 2ml of epichlorohydrin with a volume concentration of 0.4-15% was used for initial cross-linking. The cross-linking temperature of epichlorohydrin initial cross-linking was set to 70°C, and the cross-linking time was set 8h, obtain mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 50 g of anhydrous sodium sulfate and 50 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 10 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water for 3 times each, and after dehydration, take out 4g of composite microspheres Add 100ml of sodium hydroxide aqueous solution with a pH value of 14, and use 0.5ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking. The crosslinking temperature for epichlorohydrin crosslinking is set to 70°C , and the cross-linking time of epichlorohydrin cross-linking was set to 7 h to obtain cross-linked microspheres, which were then washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent F .

Example 7

A kind of preparation method of pyridine functionalized chitosan adsorbent proposed by the present embodiment comprises the following steps:

S1: 2 g of polyethyleneimine with a mass concentration of 5-100 g/L, 2 g of 2-chloromethylpyridine hydrochloride with a mass concentration of 2.5-100 g/L and 2 g of a mass concentration of 10-100 g/L Sodium carbonate was dissolved in an aqueous solution of 15 ml ethanol and 5 ml distilled water, the dissolution temperature was set at 85°C, and the dissolution time was set at 2 h, and at the same time, it was stirred by magnetic force in an oil bath at 85°C until it was evenly stirred, and then the cooling device was used to For cooling operation, the cooling device first cools at a rate of 3-5°C/min until it cools to 30°C, and then cools at a rate of 0.3-0.5°C/min until it cools to room temperature, and then uses a centrifugal device Centrifuge and filter in turn with a filter sieve, and finally spin-dry in a rotary evaporator at 50°C for 15 minutes to obtain the oil phase;

S2: Dissolve 1.5 g of chitosan powder with a mass concentration of 2-50 g/L in an aqueous solution of 2.4 ml of glacial acetic acid and 29.4 ml of distilled water, set the dissolution temperature to room temperature, and set the dissolution time to 90 min. The stirring equipment stirs until it is evenly stirred, and then the filtering equipment uses multiple screens to perform multi-stage filtration from top to bottom, and the meshes of the multiple screens from top to bottom are gradually reduced, and finally the chitosan mother liquor is obtained;

S3: Add the oil phase prepared in step S1 dropwise to the chitosan mother liquor prepared in S2, the dropping time is set to 5-60 min, the reaction time of the oil phase and the chitosan mother liquor is set to 10h, after the reaction During the process, the stirring equipment was used to stir evenly, and 4ml of epichlorohydrin with a volume concentration of 0.4-15% was used for initial crosslinking. The crosslinking temperature of epichlorohydrin initial crosslinking was set to 80 ° C, and the crosslinking time was set to 10h, obtain mixed mother liquor;

S4: pump the mixed mother liquor obtained in S3 into 1000 ml of a coagulation bath containing 50 g of anhydrous sodium sulfate and 50 g of sodium hydroxide to solidify into balls, let stand for 30 minutes, and obtain composite microspheres through precipitation and solidification;

S5: Extract the composite microspheres in step S4 through a Soxhlet extractor for 10 hours to remove the porogen remaining in the resin channels, wash with ethanol and distilled water for 3 times each, and after dehydration, take out 4g of composite microspheres Add 100ml of sodium hydroxide aqueous solution with a pH value of 14, and use 1ml of epichlorohydrin with a volume concentration of 0.01-1% for post-crosslinking. The crosslinking temperature for epichlorohydrin crosslinking is set to 80°C. And the cross-linking time of epichlorohydrin cross-linking was set to 10 h to prepare cross-linked microspheres, which were washed with distilled water until neutral, dehydrated and stored for later use to obtain pyridine functionalized chitosan adsorbent G.

In order to study the adsorption performance of the adsorbent for pyridine functionalized chitosan on heavy metals and antibiotics, the following adsorption experiments were carried out. The specific adsorption conditions were: 0.5g of the adsorbent was placed in 50ml of copper nitrate, cadmium nitrate, zinc nitrate, tetracycline, Carry out single and double component adsorption in ciprofloxacin and sulfamethoxazole, in which the concentration of heavy metals is 1mmol/l, the concentration of antibiotics is 0.5mmol/l, the initial pH of the solution is adjusted to 5, and the adsorption temperature is 25°C , the shaking rate is 130r/min, and the adsorption time is 24h. See Table 1 and Table 2 for the adsorption capacity and elemental analysis results of the composite adsorbents A-G for single heavy metal and antibiotic solution.

Composite adsorbent in table 1 embodiment A-G is to the adsorption capacity of single heavy metal, antibiotic solution:

In conjunction with Examples 1-7, the pyridine functionalized chitosan adsorbent synthesized by the method provided by the present invention is simple, low in cost, and environmentally friendly, and can be used in the fields of simultaneous removal of heavy metals and antibiotics in livestock and poultry wastewater. Wide application value.

Main technical indicators of series pyridine functionalized chitosan adsorbent prepared in the embodiment A-G of table 2

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (7)

1. a kind of preparation method of pyridine functional chitosan absorbent, which comprises the following steps:

S1: polyethyleneimine, 2- chloromethyl pyridine hydrochloride and sodium carbonate are dissolved in the aqueous solution of ethyl alcohol, while utilizing 85 Magnetic force is stirred until stir evenly in DEG C oil bath, is then cooled to room temperature using cooling device, is recycled centrifugation and filtering Processing, finally after the revolving of 1-60min, obtains oily phase；

S2: Chitosan powder is dissolved in acetic acid solution, while being stirred using mixing plant until stirring evenly, then Multistage filtering is carried out using filter plant, forms chitosan mother liquor；

S3: the oil prepared in step S1 is mutually added dropwise in the chitosan mother liquor prepared in S2, time for adding is set as 5- 60 min, oil are mutually reacted with chitosan mother liquor, are stirred uniformly during reaction using mixing plant, and use ring Oxygen chloropropane is just crosslinked, and obtains mixing mother liquor；

S4: mixing mother liquor obtained in S3 is added in coagulating bath, obtains complex microsphere through precipitating solidification；

S5: the complex microsphere in step S4 is stripped through Soxhlet extractor, removes remaining pore-foaming agent in resin duct, according to Secondary ethyl alcohol, distillation water washing, after dehydration, take out complex microsphere and are added in the aqueous solution of sodium hydroxide, use epoxychloropropane Post-crosslinking is carried out, crosslinked microsphere is made, crosslinked microsphere, which is recycled, is washed to neutrality with distillation, and dehydrated preservation is spare to obtain pyridine function Chitosan absorbent can be changed.

2. a kind of preparation method of pyridine functional chitosan absorbent according to claim 1, which is characterized in that described In S1, the mass concentration of polyethyleneimine is 5-100 g/L, and the mass concentration of 2- chloromethyl pyridine hydrochloride is 2.5-100 g/ L, the mass concentration of sodium carbonate are 10-100 g/L, and the volumetric concentration of the aqueous solution of ethyl alcohol is 5-80%, the aqueous solution of ethyl alcohol it is molten Solving temperature setting is 20-90 DEG C, and the dissolution time of the aqueous solution of ethyl alcohol is set as 2-10 h.

3. a kind of preparation method of pyridine functional chitosan absorbent according to claim 1, which is characterized in that described In S2, the mass concentration of Chitosan powder is 2-50 g/L, and the volumetric concentration of acetic acid solution is 1-8%, the dissolution of acetic acid solution Temperature setting is 20-80 DEG C, and the dissolution time of acetic acid solution is set as 20-90 min.

4. a kind of preparation method of pyridine functional chitosan absorbent according to claim 1, which is characterized in that described In S3, oil is mutually set as 1-60 h with the reaction time of chitosan mother liquor, and the volumetric concentration of epoxychloropropane is 0.4-15%, The crosslinking temperature that epoxychloropropane is just crosslinked is set as 20-80 DEG C, and crosslinking time is set as 1-20 h.

5. a kind of preparation method of pyridine functional chitosan absorbent according to claim 1, which is characterized in that described In S4, coagulating bath is molten dissolved with mixing one or more of in sodium sulphate, sodium hydroxide, sodium tripolyphosphate and sodium pyrophosphate Liquid.

6. a kind of preparation method of pyridine functional chitosan absorbent according to claim 5, which is characterized in that described The mass concentration of sodium sulphate and sodium hydroxide is respectively 10-200 g/L and 10-200 g/L.

7. a kind of preparation method of pyridine functional chitosan absorbent according to claim 1, which is characterized in that described In S5, the dosage of complex microsphere is 2-40 g/L, and the extraction times of Soxhlet extractor are set as 2-10 h, the water of sodium hydroxide The pH of solution is 10-14, and the volumetric concentration of epoxychloropropane is 0.01-1%, and the crosslinking temperature of epoxychloropropane crosslinking is set as 20-80 DEG C, and the crosslinking time of epoxychloropropane crosslinking is set as 1-10 h.