CN111410723A

CN111410723A - Porous boron affinity imprinted polymer and preparation method and application thereof

Info

Publication number: CN111410723A
Application number: CN202010166300.2A
Authority: CN
Inventors: 何沛谚; 潘建明; 刘金鑫
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2020-03-11
Filing date: 2020-03-11
Publication date: 2020-07-14

Abstract

The invention provides a porous boron affinity imprinted polymer, a preparation method and application thereof, belonging to the technical field of advanced chemical separation materials; the Pickering high internal phase emulsion is combined with the boron affinity molecularly imprinted polymer, and the prepared imprinted polymer can effectively avoid stacking of the nanosheet adsorbent, so that the adsorption and separation effect is improved, and the polymer has a good application prospect in the field of catechol enriched in water.

Description

Porous boron affinity imprinted polymer and preparation method and application thereof

Technical Field

The invention belongs to the technical field of advanced chemical separation materials, and relates to a porous boron affinity imprinted polymer, and a preparation method and application thereof.

Background

Catechol is a phenolic endocrine disruptor with ortho-dihydroxy structure, mainly found in waste water of cosmetics, dyes, pesticides and pharmaceutical industries, and has high toxicity and degradation resistance in ecological environment. Meanwhile, active free radicals formed by the autoxidation of the active free radicals can damage nerve cells, cardiac muscle cells and even DNA in a human body, thereby causing the problems of carcinogenesis, teratogenicity and the like. Therefore, the pyrocatechol in the environmental water body or the drinking water needs to be selectively separated and enriched.

The boron affinity material is used for separating and enriching pyrocatechol because of the unique affinity to the compound containing ortho-dihydroxy. However, the boron affinity material can only be used for enriching a class of substances with ortho-dihydroxy structures, and the identification and separation of targeted catechol molecules in complex samples are difficult to realize.

The molecular imprinting technology is a material preparation technology for simulating antigen-antibody specific binding on a molecular level, template molecules are inlaid in the material in the process of preparing the material, and then the template molecules are washed away, so that a cavity specifically bound with the molecules can be formed, and the specific recognition of target molecules is realized. In the prior art, the boron affinity molecularly imprinted polymer is generally nano-particles, is difficult to collect and is easy to lose in the adsorption separation process.

Disclosure of Invention

In order to overcome one of the defects in the prior art, the invention provides a porous boron affinity imprinted polymer, and a preparation method and application thereof.

The invention firstly provides a porous boron affinity imprinted polymer, wherein the porous boron affinity imprinted polymer loads a nano boron affinity molecularly imprinted polymer on the surface of a porous micron matrix, and the porous boron affinity imprinted polymer is provided with a macroporous polymeric foam matrix.

In order to solve the problems, the invention also provides a method for preparing the porous boron affinity imprinted polymer by using the stable high internal phase emulsion of the bernoulli nanosheet, which comprises the following specific steps:

(1) synthesis of 10% polystyrene-maleic anhydride (HSMA) surfactant:

mixing toluene, styrene (St), Maleic Anhydride (MA) and Azobisisobutyronitrile (AIBN), intermittently ultrasonically dispersing, introducing nitrogen for 30 min after uniform dispersion, heating to 85 ℃, reacting for 3h under stirring reflux of magnetons to obtain white granular polystyrene-maleic anhydride copolymer (SMA), washing the product with toluene, and drying; adding SMA into distilled water and sodium hydroxide, and stirring at 80 ℃ for 3.0 h to obtain 10% HSMA solution;

further, in the step (1), the amount ratio of the toluene, St, MA and AIBN is 100-200 m L: 4-6.5m L: 2-8mg:0.005-0.1 g.

Furthermore, in the step (1), the using amount ratio of the SMA, the distilled water and the sodium hydroxide is 2-6g:20-60m L: 1-2 g.

(2) Synthesis of the Janus nanosheets (NS-1):

adding 10% HSMA solution into a certain amount of distilled water, stirring, adding 2M HCl dropwise, adjusting pH to about 3.0, and removing flocculent precipitate; mixing the water phase with a certain amount of n-decane, stirring uniformly, sequentially dropwise adding 3-Chloropropyltrimethoxysilane (CPTMS), tetraethyl orthosilicate (TEOS) and 3-Aminopropyltriethoxysilane (APTES), stirring for 10 min, transferring to a 60 ℃ water bath, standing for 12h, and fully hydrolyzing and polycondensing the silane coupling agent. And (3) centrifugally separating a solid product, namely the Bernoulli-structure silicon spheres, performing strong ultrasonic treatment for 2.0 h to break the silicon shell into sheets to obtain NS-1, washing the NS-1 with distilled water and ethanol respectively to remove oil-water phases, and drying the NS-1 in a vacuum oven at 45 ℃ for later use.

Further, in the step (2), the using ratio of the distilled water to the 10% HSMA solution is 50-150m L: 5-20m L.

Further, in the step (2), the dosage of the n-decane is 7-30m L, the dosage of the CPTMS is 100-500 mu L, the dosage of the TEOS is 2-5m L, and the dosage of the APTES is 100-500 mu L.

(3) NS-1 Pickering high internal phase emulsion template preparation of porous polymers (NS-1-HIPEs):

adding NS-1 and Tween-80 into distilled water, uniformly performing ultrasonic treatment for 30 min, sequentially adding acrylamide, N-methylene bisacrylamide and ammonium persulfate, and stirring to fully and uniformly disperse the water phase. Then, slowly dropping liquid paraffin under stirring, continuously stirring for 30 min to obtain a Pickering high internal phase emulsion template, transferring the emulsion into an ampoule bottle, and heating in a water bath at 70 ℃ for 12 h. Taking out the product after reaction, performing Soxhlet extraction by using acetone, washing the product with distilled water and ethanol respectively after two days, and drying in a vacuum oven at 45 ℃ to obtain the block-shaped product NS-1-HIPEs.

Further, in the step (3), the dosage ratio of the NS-1, the Tween-80 and the distilled water is 150-300 mg: 5-50 μ L: 1-10m L, the addition amount of the acrylamide is 0.5-2g, the addition amount of the N, N-methylene bisacrylamide is 0.2-0.5g, the addition amount of the ammonium persulfate is 10-30mg, and the addition amount of the liquid paraffin is 5-30m L.

(4) Preparation of porous boron affinity imprinted adsorbent (NS-1-MIPs):

NS-1-HIPEs are used as a substrate, and a chlorine functional group fixed on the outer surface of the nano sheet is utilized to initiate atom transfer radical polymerization reaction, so that a boron affinity imprinted polymer is grafted on the outer surface of the nano sheet.

The method comprises the following steps of dissolving tetravinyl benzene boric acid (VPBA) and catechol in a mixed solution of distilled water and isopropanol, and standing in a dark place under the protection of nitrogen to ensure that a boric acid group and ortho-dihydroxy are fully self-assembled. Soaking certain amount of NS-1-HIPEs in the self-assembly solution, and stirring with magneton for 1.0 h. Mixing N, N, N' -Pentamethyldiethylenetriamine (PMDETA), Ethylene Glycol Dimethacrylate (EGDMA) and CuCl₂•2H₂And O is added into the self-assembly liquid after being mixed, ascorbic acid is rapidly added, the mixture is continuously stirred and reacts for 6.0 hours, and the whole reaction process is carried out under the protection of nitrogen at room temperature. After the reaction is finished, eluting the catechol template in a mixed solution of methanol and acetic acid (V/V = 9: 1) for at least 4 h, and then elutingWashing the product with ethanol and distilled water, and drying to obtain NS-1-MIPs.

Non-imprinted polymers (NS-1-NIPs) were prepared in a similar manner to NS-1-MIPs except that no catechol was added to the self-assembly solution.

Further, in the step (4), the volume ratio of the distilled water to the isopropanol is 0.1-1: 2-8; the addition amount of the VPBA is 0.5-1.5 g; the addition amount of the catechol is 0.2-1.5 g; the mass of the NS-1-HIPEs is 0.1-0.5 g; said PMDETA, EGDMA, CuCl₂•2H₂The mass ratio of the O to the ascorbic acid is 20-200 mu L: 2-10m L: 10-80mg:10-500 mg.

The invention also provides application of the porous boron affinity imprinted polymer prepared from the stable high internal phase emulsion of the Bernoulli nano-sheet in enriching and separating catechol in water.

The invention has the beneficial effects that:

compared with the prior art, the invention adopts the anisotropic emulsion to prepare the NS-1 with one surface provided with the amino group and one surface provided with the chlorine group as the stable particles to emulsify the Pickering high-internal emulsion, and can obtain a more stable emulsion template.

According to the invention, the nanosheet with post-modification activity is fixed on the surface of the porous polymer matrix by initiating the external phase polymerization of the Pickering high internal phase emulsion, so that the stacking of the nanosheet adsorbent can be effectively avoided, and the adsorption separation effect is improved.

NS-1-MIPs have the advantages of macroporous polymeric foam matrix and nano imprinted polymer grafted on the surface of the nanosheet, and have the advantages of convenience in separation of the micro adsorbent and high specific surface area of the nano imprinted polymer. The invention provides a new idea for assembling the nano imprinted polymer on the surface of the porous polymer matrix.

Drawings

FIG. 1 is SEM images of NS-1 (A), NS-1-HIPEs (B, B), and NS-1-MIPs (C, C), where B is an SEM detail view of NS-1-HIPEs, and C is an SEM detail view of NS-1-MIPs.

FIG. 2 is an infrared spectrum of NS-1, NS-1-HIPEs, and NS-1-MIPs.

FIG. 3 shows XPS spectra of NS-1, NS-1-HIPEs and NS-1-MIPs.

FIG. 4 shows thermogravimetric curves obtained by thermogravimetric analysis of NS-1, NS-1-HIPEs, and NS-1-MIPs.

FIG. 5 is a graph of the adsorption capacities of NS-1-MIPs and NS-1-NIPs at different pH values.

FIG. 6 is a graph showing the kinetics of catechol adsorption by NS-1-MIPs and NS-1-NIPs.

FIG. 7 is an adsorption isotherm of NS-1-MIPs and NS-1-NIPs at 298K and 308K.

FIG. 8 shows the adsorption amounts of NS-1-MIPs and NS-1-NIPs to Catechol, TCP, QRT and HDQ.

Detailed Description

The invention will be further described with reference to specific examples and figures, but the scope of the invention is not limited thereto.

Example 1:

(1) synthesis of 10% polystyrene-maleic anhydride (HSMA) surfactant

150m of L toluene, 5.8 m of L styrene (St), 5.0 g of MA and 0.01g of AIBN are mixed and subjected to intermittent ultrasonic dispersion, nitrogen is introduced for 30 min after uniform dispersion, the mixture is heated to 85 ℃, and the mixture reacts for 3.0 h under the stirring reflux of magnetons to obtain white particle styrene-maleic anhydride copolymer (SMA), the obtained solid is washed by toluene and dried in a vacuum oven at the temperature of 60 ℃, 5.0 g of SMA is taken, 45 m of L distilled water and 1.35 g of sodium hydroxide are added, and the mixture is stirred for 3.0 h at the temperature of 80 ℃ to obtain 10 percent of HSMA solution.

(2) Synthesis of Janus nanosheets (NS-1)

Adding 15M L10% of HSMA solution into 75M L distilled water, fully stirring and uniformly mixing, dropwise adding 2M HCl, adjusting the pH value to be about 3.0, and generating no flocculent precipitate, mixing the aqueous phase with 14M L n-decane, stirring at 12000 rpm for 5.0min, sequentially dropwise adding 340 mu L CPTMS, 4.0M L TEOS and 340 mu L APTES, stirring for 10 min, transferring to a 60 ℃ water bath, standing for 12h, fully hydrolyzing and polycondensing a silane coupling agent, crushing a solid product, namely a Bernoulli structure silicon ball, centrifugally separating, strongly performing ultrasonic treatment for 2.0 h to obtain NS-1, washing with distilled water and ethanol respectively, removing oil-water two phases, and drying in a 45 ℃ vacuum oven for later use.

(3) Preparation of porous Polymer (NS-1-HIPEs) from NS-1 Pickering high Inward emulsion template

Adding 250 mg of NS-1 into 30 mu L Tween-80 in 4.0 m L water, uniformly performing ultrasonic treatment for 30 min, sequentially adding 1.4g of acrylamide, 0.309 g N, N-methylene bisacrylamide and 20 mg of ammonium persulfate, stirring at 7000 rpm to fully disperse the water phase uniformly, then slowly dropwise adding 16 m L liquid paraffin under stirring, continuously stirring for 30 min to obtain a Pickering high internal phase emulsion template, transferring the emulsion into an ampoule bottle, heating in 70 ℃ water bath for 12h, reacting, taking out the product, performing Soxhlet extraction by using acetone, washing the product with distilled water and ethanol after two days, and drying in a vacuum oven at 45 ℃ to obtain blocky products NS-1-HIPEs.

(4) Preparation of porous boron affinity imprinted adsorbent (NS-1-MIPs)

Using NS-1-HIPEs as a matrix, initiating an atom transfer radical polymerization reaction by using a chlorine functional group fixed on the outer surface of a nano sheet, and grafting a boron affinity imprinted polymer on the outer surface of the nano sheet, wherein the specific method comprises the following steps of dissolving 1.074 g of VPBA and 859.2mg of pyrocatechol in a mixed solution of 0.75 m L water and 4.25 m L isopropanol, standing in the dark for more than 4.0h under the protection of nitrogen, fully self-assembling a boric acid group and cis-dihydroxy, soaking 300mg of NS-1-HIPEs in a self-assembling solution, stirring by using a magneton for 1.0 h, and then stirring by using 120 mu L of PMDETA, 7.2 m L of EGDMA and 40 mg of CuCl for 1.0 h₂•2H₂And O is added into the self-assembly liquid after being mixed, 180 mg of ascorbic acid is rapidly added, the reaction is continuously stirred for 6.0 hours, and the whole reaction process is carried out under the protection of nitrogen at room temperature. After the reaction is finished, eluting the catechol template in a mixed solution of methanol and acetic acid (V/V = 9: 1) for at least 4 h, washing the product by using ethanol and distilled water respectively, and drying in a vacuum oven at 45 ℃ to obtain NS-1-MIPs.

Non-imprinted polymers (NS-1-NIPs) were prepared in analogy to NS-1-MIPs, but without the addition of catechol to the self-assembly solution.

NS-1, NS-1-HIPEs, and NS-1-MIPs prepared in this example were characterized by JSM-7800F ultra high resolution thermal field emission scanning electron microscopy (JEO L L td. Japan).

FIG. 1 is an SEM image of NS-1 (A), NS-1-HIPEs (B, B), and NS-1-MIPs (C, C). As can be seen from the figure (A), the two roughness degrees of NS-1 are greatly different, because NS-1 is prepared by an anisotropic emulsion method, a nanosheet with a double-sided structure is obtained, the smooth side has amino groups, and the side with chlorine has higher roughness. From the graphs (B) and (C), it can be seen that both NS-1-HIPEs and NS-1-MIPs have typical high internal phase emulsion structures, are porous and have complicated pore channels, and from the detail graphs (B) and (C) of the two, the surface of the high internal phase emulsion changes from smooth to rough, which proves the successful introduction of the imprinted polymer. Although the high internal phase emulsion is formed by contacting the interior of the emulsion with a hydrophilic ammonia base, the polymerized high internal phase remains microscopically smooth on the outside.

Example 2:

(1) synthesis of 10% polystyrene-maleic anhydride (HSMA) surfactant:

taking 120 m L toluene, 5.8 m L styrene (St), 8 g MA and 0.1g AIBN, mixing and intermittently ultrasonically dispersing, introducing nitrogen for 30 min after uniform dispersion, heating to 85 ℃, reacting for 3.0 h under magneton stirring reflux to obtain white particle styrene-maleic anhydride copolymer (SMA), flushing the obtained solid with toluene, drying in a vacuum oven at 60 ℃, taking 5.0 g SMA, adding 60m L distilled water and 2g sodium hydroxide, and stirring for 3.0 h at 80 ℃ to obtain 10% HSMA solution.

(2) Synthesis of the Janus nanosheets (NS-1):

adding 20M L10% of HSMA solution into 100M L distilled water, fully stirring and uniformly mixing, dropwise adding 2M HCl, adjusting the pH value to be about 3.0, and generating no flocculent precipitate, mixing the aqueous phase with 20M L n-decane, stirring at 12000 rpm for 5.0min, sequentially dropwise adding 500 mu L CPTMS, 5M L TEOS and 500 mu L APTES, stirring for 10 min, transferring to a 60 ℃ water bath kettle, standing for 12h, fully hydrolyzing and polycondensing a silane coupling agent, crushing a solid product, namely a Bernoulli structure silicon ball, centrifugally separating, strongly performing ultrasonic treatment for 2.0 h, crushing the silicon shell into sheets to obtain NS-1, washing with distilled water and ethanol respectively, removing oil-water two phases, and drying in a 45 ℃ vacuum oven for later use.

(3) Preparation of porous polymers (NS-1-HIPEs) from NS-1 Pickering high internal emulsion template:

adding 300mg of NS-1 into 50 mu L Tween-80 in 10m L water, uniformly performing ultrasonic treatment for 30 min, sequentially adding 2.0g of acrylamide, 0.5g N, N-methylene bisacrylamide and 30mg of ammonium persulfate, stirring at 7000 rpm for 5.0min to fully disperse the water phase uniformly, then slowly dropwise adding 30m L liquid paraffin under stirring to obtain a Pickering high internal phase emulsion template, continuously stirring for 30 min, transferring the emulsion into an ampoule, heating in 70 ℃ water bath for 12h, reacting, taking out the product, performing Soxhlet extraction by using acetone, washing the product with distilled water and ethanol after two days, and drying in a vacuum oven at 45 ℃ to obtain the blocky product NS-1-HIPEs.

(4) Preparation of porous boron affinity imprinted adsorbent (NS-1-MIPs)

Using NS-1-HIPEs as a matrix, initiating an atom transfer radical polymerization reaction by using a chlorine functional group fixed on the outer surface of a nano sheet, and grafting a boron affinity imprinted polymer on the outer surface of the nano sheet, wherein the specific method comprises the following steps of dissolving 1.5g of VPBA and 1.5g of catechol in a mixed solution of 1 m L water and 8m L isopropanol, standing in the dark for more than 4.0h under the protection of nitrogen, fully and automatically assembling a boric acid group and cis-dihydroxy, soaking 500mg of NS-1-HIPEs in a self-assembly liquid, stirring for 1.0 h by using a magneton, and then carrying out 200 mu L PMDETA, 10m L EGDMA and 80mg of CuCl₂•2H₂And O is added into the self-assembly liquid after being mixed, 500mg of ascorbic acid is rapidly added, the reaction is continuously stirred for 6.0 hours, and the whole reaction process is carried out under the protection of nitrogen at room temperature. After the reaction is finished, eluting the catechol template in a mixed solution of methanol and acetic acid (V/V = 9: 1) for at least 4 h, washing the product by using ethanol and distilled water respectively, and drying in a vacuum oven at 45 ℃ to obtain NS-1-MIPs.

NS-1, NS-1-HIPEs and NS-1-MIPs prepared in this example were measured on a Nicolet Nexus 470FTIR spectrometerFourier transform infrared spectra (4000-. By comparing the three infrared spectra, it can be seen that NS-1 is changed from silicon-based material to carbon-based material after forming high internal phase emulsion, and the spectra are also changed greatly. The most predominant absorption peak of NS-1 is at 1093 cm^-1Appears as a characteristic peak of Si-O-Si, and the rest smaller absorption peak appears at 1714 cm^-1At a sum of 808cm^-1The vibration is respectively classified into C = O stretching vibration and C-H out-of-plane bending vibration because of a small amount of carbon functional groups contained in the functionalized silane coupling agent; 3348 cm after formation of the high internal phase material^-1Broad peak appearing in the place, 3200 cm^-1The absorption peak at (A) is an association absorption peak formed due to O-H stretching vibration. 2931 cm^-1The absorption peak is generated by C-H stretching vibration. 1664 cm^-1The absorption peak at (a) is attributed to the C = C stretching vibration. 1108 cm^-1The absorption peak appeared here, which is attributed to C-O stretching vibration. 1452 cm^-1And 1415 cm^-1The peak is obtained by splitting an absorption peak formed by bending vibration in C-H plane, and is 1319 cm^-1And 1348 cm^-1Split peaks are formed. After blotting modification of NS-1-HIPEs, 1346 cm^-1The overall peak is present and is attributed to B = O tensile vibration, indicating successful intervention of the boronic acid material.

Example 3:

(1) synthesis of 10% polystyrene-maleic anhydride (HSMA) surfactant:

100 m of L toluene, 4 m of L styrene (St), 2g of MA and 0.005g of AIBN are mixed and subjected to intermittent ultrasonic dispersion, nitrogen is introduced for 30 min after uniform dispersion, the mixture is heated to 85 ℃, and the mixture reacts for 3.0 h under magneton stirring reflux to obtain white particle styrene-maleic anhydride copolymer (SMA), the obtained solid is washed for more than three times by toluene and dried in a vacuum oven at the temperature of 60 ℃, 5.0 g of SMA is taken, 20m of L distilled water and 1g of sodium hydroxide are added, and the mixture is stirred for 3.0 h at the temperature of 80 ℃ to obtain 10% of HSMA solution.

(2) Synthesis of the Janus nanosheets (NS-1):

adding 5M L10% of HSMA solution into 50M L distilled water, fully stirring and uniformly mixing, dropwise adding 2M HCl, adjusting the pH value to be about 3.0, and generating no flocculent precipitate, mixing the aqueous phase with 7M L n-decane, stirring at 12000 rpm for 5.0min, sequentially dropwise adding 100 mu L CPTMS, 2M L TEOS and 100 mu L APTES, stirring for 10 min, transferring to a 60 ℃ water bath kettle, standing for 12h, fully hydrolyzing and polycondensing a silane coupling agent, crushing a solid product, namely a Bernoulli structure silicon ball, centrifugally separating, strongly performing ultrasonic treatment for 2.0 h, crushing the silicon shell into sheets to obtain NS-1, washing with distilled water and ethanol respectively, removing oil-water two phases, and drying in a 45 ℃ vacuum oven for later use.

adding 150 mg of NS-1 into 5 mu L Tween-80 in 1 m L water, uniformly performing ultrasonic treatment for 30 min, sequentially adding 0.5g of acrylamide, 0.2 g N, N-methylene bisacrylamide and 10 mg of ammonium persulfate, stirring at 7000 rpm for 5.0min to fully disperse the water phase uniformly, then slowly dropwise adding 5m L liquid paraffin under stirring to obtain a Pickering high internal phase emulsion template after continuously stirring for 30 min, transferring the emulsion into an ampoule, heating in 70 ℃ water bath for 12h, reacting, taking out the product, performing Soxhlet extraction by using acetone, washing the product with distilled water and ethanol after two days, and drying in a vacuum oven at 45 ℃ to obtain the blocky product NS-1-HIPEs.

(4) Preparation of porous boron affinity imprinted adsorbent (NS-1-MIPs):

using NS-1-HIPEs as a matrix, initiating an atom transfer radical polymerization reaction by using a chlorine functional group fixed on the outer surface of a nano sheet, and grafting a boron affinity imprinted polymer on the outer surface of the nano sheet, wherein the specific method comprises the following steps of dissolving 0.5g of VPBA and 0.1g of catechol in a mixed solution of 0.1 m L water and 2m L isopropanol, standing in the dark for more than 4.0h under the protection of nitrogen, fully self-assembling a boric acid group and cis-dihydroxy, soaking 100 mg of NS-1-HIPEs in a self-assembly liquid, stirring by using a magneton for 1.0 h, and then, stirring by using 20 mu L PMA, 2m L EGDETDDMA and 10 mg of CuCl for 1.0 h₂•2H₂Adding O into the self-assembly liquid after mixing, quickly adding 50 mg of ascorbic acid, continuously stirring for reacting for 6.0 h, and reacting under the protection of nitrogen at room temperatureThe process is carried out. After the reaction is finished, eluting the catechol template in a mixed solution of methanol and acetic acid (V/V = 9: 1) for at least 4 h, washing the product by using ethanol and distilled water respectively, and drying in a vacuum oven at 45 ℃ to obtain NS-1-MIPs.

FIG. 3 shows XPS spectra of NS-1, NS-1-HIPEs and NS-1-MIPs, from which it can be seen that characteristic peaks appear at 103.1, 154.2, 285.1, 399.1 and 532.1 eV, which can be assigned to corresponding Si 2p, Si 2s, C1 s, N1s and O1 s, respectively. In the spectrum of NS-1, the characteristic peak of Si is more obvious, and the characteristic peak of N is not obvious, because the proportion of the total weight is smaller due to the addition of the silane coupling agent containing amino. NS-1 sheets as stable particles are added to the high internal phase emulsion and polymerized to obtain NS-1-HIPEs. In the NS-1-HIPEs spectrum, the characteristic peak of Si becomes smaller as compared with NS-1, since the overall material realizes the conversion from a silicon-based material to a carbon-based material, while the characteristic peaks of C1 s, N1s and O1 s become higher, since the polymerized monomer of acrylamide is present in a large amount, and also the stable presence and polymerization of a high internal phase emulsion is confirmed. After ARGET-ATRP reaction is carried out on NS-1-HIPEs, a spectrogram of NS-1-MIPs has a characteristic peak at 190.1 eV, which is attributed to B1 s, and the effective introduction of boric acid groups is illustrated, so that the successful preparation of NS-1-MIPs materials is also proved, and the result is corresponded to the result obtained in an infrared spectrogram.

TGA characterization of powder samples (30 mg) was performed using Diamond TG/DTA Instruments (Perkin-Elmer, U.S. A.) with a heating rate of 5.0C/min under a nitrogen atmosphere from room temperature to 1000 deg.C,

FIG. 4 shows thermogravimetric curves obtained by thermogravimetric analysis of NS-1, NS-1-HIPEs, and NS-1-MIPs. NS-1 consists mainly of silica, amino and halogen functional groups, and it is largely divided into three weight loss processes. The first stage is that before 100 ℃, the weight loss rate is about 4.66 percent, which can be attributed to the evaporation of water in the material; the second stage is that slow weightlessness behavior occurs between 100-400 ℃; the last stage is after 400 ℃. The weight loss ratios in the last two stages are 7.91% and 13.96%, respectively, and can be attributed to thermal decomposition of functional groups in the two functional silane coupling agents. Whereas for NS-1-HIPEs and NS-1-MIPs, the thermogravimetric curves are much different from NS-1, yielding a weight loss difference of about 40.00%. The early weight loss of NS-1-HIPEs and NS-1-MIPs was similar, with 7.78% and 8.76% weight loss, respectively, compared to the loss of moisture achieved before 100 deg.C, which is probably higher than NS-1 because they have more porous structures and pore size channels as high internal phase emulsions. The weight loss ratios of NS-1-HIPEs and NS-1-MIPs were about 12.35% and 18.07%, respectively, at 200 ℃ and 350 ℃. And at the temperature of 350-400 ℃, the two materials are quickly weightless, and the weightless rates respectively reach 38.62 percent and 42.54 percent. The weight loss in these two stages is mainly due to the destruction of the organic carbon material in the high internal phase by high temperature. After 400 ℃, NS-1-HIPEs and NS-1-MIPs underwent slow weight loss, eventually resulting in a 9.78% weight loss difference, which can be attributed to the introduction of imprinted polymers in NS-1-MIPs, demonstrating the successful introduction of the imprinted layer.

Example 4:

the method comprises the specific steps of preparing catechol test solutions (with concentration values of 20 mg/L) with pH values of 6.5, 7.4, 8.5 and 9.2, respectively adding 5.0mg of accurately weighed adsorbents (NS-1-MIPs or NS-1-NIPs) into the catechol test solutions with different pH values, performing static adsorption in a water bath oscillator at 298K, centrifugally separating the adsorbents after 2.0 h, measuring the adsorbed solutions at 276 nm wavelength by an ultraviolet-visible spectrophotometry, and calculating the equilibrium adsorption capacity (Qe, mu mol/g) after repeating three times

。

By studying the boron affinity binding capacity of NS-1-MIPs and NS-1-NIPs under different pH values, as shown in FIG. 5, at a pH value of 8.5, the binding capacity of boric acid groups and cis-dihydroxy in catechol is strongest, the adsorption effect of the adsorbent is best, the adsorption quantity of NS-1-MIPs reaches 36.6 mu mol/g, and the adsorption quantity of NS-1-NIPs reaches 11.2 mu mol/g. Before the pH value reaches 8.5, the binding capacity shows an upward trend, and after the pH value is more than 8.5, excessive hydroxide radicals in the environment can cause the dissociation of cis-dihydroxy, so that the binding sites in the catechol are lost.

Example 5:

in this example, the kinetics of catechol adsorption by NS-1-MIPs and NS-1-NIPs were examined, 5.0mg of adsorbents (NS-1-MIPs and NS-1-NIPs) were precisely weighed into 10m L centrifuge tubes, 5.0mg of a catechol standard buffer solution (PBS, pH 8.5) 5.0m L at an initial concentration of 20 mg/L was added, static adsorption was performed in 298K water bath shaking after sealing, after a certain time interval (5.0, 10, 15, 60, 120, 240 and 360 min), the adsorbents were separated by centrifugation, the catechol concentration in the supernatant was determined by UV-vis at 276 nm, the whole process was repeated at least three times, and the adsorption amount ((N), (N) and (N) were measuredQ _tMu mol/g) is calculated by

。

As shown in FIG. 6, the adsorption process of NS-1-MIPs and NS-1-NIPs can be divided into two stages. The first stage is a rapid adsorption stage, and reaches 75% of the equilibrium adsorption amount 15 min after the start; within 15 min to 60 min, the adsorption rate becomes slow and gradually approaches the adsorption equilibrium, and at the moment, the adsorption amount reaches more than 90 percent of the equilibrium adsorption amount. The adsorption rate trends of the imprinted material and the non-imprinted material are basically kept consistent, and the equilibrium adsorption capacity of the NS-1-MIPs is more than two times higher than that of the NS-1-NIPs, so that the great introduction of effective binding sites in the imprinted material is proved.

Example 6:

in the example, the adsorption performance of NS-1-MIPs and NS-1-NIPs on catechol at different temperatures is examined, NS-1-MIPs and NS-1-NIPs are used as adsorbents, and the adsorption capacity of NS-1-MIPs and NS-1-NIPs on catechol at different concentrations and temperatures is studied, wherein the specific steps are that 5.0m of standard catechol buffer solution (PBS, pH 8.5) with the concentration of 20, 40, 60, 100 and 200 mg/L is respectively added into a 10m L centrifuge tube, 5.0mg of adsorbent (NS-1-MIPs or NS-1-NIPs) is mixed with the standard catechol buffer solution, the adsorbent is collected by centrifugation after 2.0 h of water bath oscillation adsorption, and the concentrated catechol concentration in the test solution is determined by UV-visAnd (4) degree. The above steps were carried out under conditions of 298K and 308K, respectively, and repeated three times, and the obtained data were used for the equilibrium adsorption amount: (Q _eμ mol/g) according to the following formula:

。

the adsorption performance of NS-1-MIPs and NS-1-NIPs on catechol at different temperatures is shown in FIG. 7. Adsorption experiments at different temperatures show that NS-1-MIPs and NS-1-NIPs are more suitable for being combined with catechol at 308K, which indicates that higher temperature is more favorable for adsorption reaction, and the process is also known to be an endothermic process. This is probably due to the possibility of more "movement" of the catechol molecule to the imprinted binding sites under high temperature conditions. And NS-1-MIPs and NS-1-NIPs show more excellent adsorption performance at any temperature, which indicates that the imprinting is effective.

In addition, the imprinted polymer prepared by the invention can effectively avoid stacking of the nano-sheet adsorbent when degrading o-dihydroxy, thereby improving the adsorption separation effect and having good application prospect in catechol enriched in water.

Example 7:

in this example, the adsorption specificity of NS-1-MIPs was examined, 5.0mg of adsorbent (NS-1-MIPs or NS-1-NIPs) was added to a 5.0m L single adsorbate solution of 298K catechol, quercetin, 2,4, 6-trichlorophenol, and hydroquinone (all at 20 mg/L), and after 2.0 h of static adsorption, the adsorbent was collected by centrifugation, and the concentrations of four compounds in the filtrate were determined by UV-vis, the test wavelength of catechol was 276 nm, the test wavelength of quercetin was 374 nm, the test wavelength of hydroquinone was 292 nm, and the test wavelength of 2,4, 6-trichlorophenol was 288 nm, and the test wavelength was tested in parallel three times, and the average value was taken, and then calculated according to the formula:

。

FIG. 8 shows that the four substances adsorbed by NS-1-MIPs are 36.40 μmol/g, 2.199 μmol/g, 5.384 μmol/g and 2.695 μmol/g, respectively, which fully illustrates the excellent catechol-recognizing performance of NS-1-MIPs. The adsorption amounts of NS-1-NIPs to catechol, 2,4, 6-trichlorophenol, quercetin and hydroquinone were 10.90. mu. mol/g, 2.542. mu. mol/g, 5.384. mu. mol/g and 2.695. mu. mol/g, respectively. In the absence of imprinted recognition sites, the presence of trace amounts of both adsorbents for 2,4, 6-trichlorophenol and hydroquinone was negligible. And quercetin is adsorbed in a small amount because it also has a ortho-dihydroxy structure.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.

Claims

1. The preparation method of the porous boron affinity imprinted polymer is characterized by comprising the following steps:

(1) synthesizing 10% polystyrene-maleic anhydride (HSMA) surfactant;

(2) synthesizing a Knudus nanosheet (NS-1);

adding NS-1 and Tween-80 into distilled water, uniformly performing ultrasonic treatment, sequentially adding acrylamide, N-methylene bisacrylamide and ammonium persulfate, and stirring to fully and uniformly disperse a water phase; slowly dripping liquid paraffin under stirring, continuously stirring to obtain a Pickering high internal phase emulsion template, and carrying out water bath reaction; taking out the product after reaction, performing Soxhlet extraction by using acetone, washing and drying the product by using distilled water and ethanol respectively after two days to obtain a blocky product NS-1-HIPEs;

(4) preparation of porous boron affinity imprinted adsorbents (NS-1-MIPs):

NS-1-HIPEs are used as a matrix, and boron affinity imprinted polymers are grafted on the outer surface of the nanosheet.

2. The method according to claim 1, wherein in the step (3), the amount ratio of NS-1, Tween-80 and distilled water is 150 mg: 5-50 μ L: 1-10m L.

3. The production method according to claim 1, wherein in the step (3), the acrylamide is added in an amount of 0.5 to 2 g.

4. The production method according to claim 1, wherein in the step (3), the N, N-methylenebisacrylamide is added in an amount of 0.2 to 0.5 g.

5. The method according to claim 1, wherein in the step (3), the amount of ammonium persulfate to be added is 10 to 30 mg.

6. The production method according to claim 1, wherein in the step (3), the liquid paraffin is added in an amount of 5 to 30m L.

7. The preparation method according to claim 1, wherein in the step (3), the conditions of the water bath reaction are as follows: heating in 70 deg.C water bath for 12 h.

8. The porous boron affinity imprinted polymer prepared by the method of any one of claims 1 to 7, wherein the porous boron affinity imprinted polymer has a macroporous polymeric foam matrix, and the nano boron affinity molecularly imprinted polymer is loaded on the surface of the porous micro matrix.

9. The use of the porous boron affinity imprinted polymer of claim 8 for the enrichment and separation of catechol in water.