CN112898455B - Chromium (VI) molecular imprinting material and preparation method and application thereof - Google Patents

Chromium (VI) molecular imprinting material and preparation method and application thereof Download PDF

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CN112898455B
CN112898455B CN202110099966.5A CN202110099966A CN112898455B CN 112898455 B CN112898455 B CN 112898455B CN 202110099966 A CN202110099966 A CN 202110099966A CN 112898455 B CN112898455 B CN 112898455B
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chromium
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graft copolymer
water
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CN112898455A (en
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刘辉
陈尚龙
陈安徽
师聪
胡译文
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Xuzhou University of Technology
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/268—Polymers created by use of a template, e.g. molecularly imprinted polymers
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    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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    • C02F1/285—Treatment of water, waste water, or sewage by sorption using synthetic organic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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    • C02F2101/20—Heavy metals or heavy metal compounds
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Abstract

The invention relates to a chromium (VI) molecularly imprinted material, a preparation method and application thereof. The obtained chromium (VI) molecularly imprinted material has high removal rate, good selectivity and high adsorption capacity, and has good application prospect in the treatment of chromium (VI) containing wastewater.

Description

Chromium (VI) molecular imprinting material and preparation method and application thereof
Technical Field
The disclosure relates to a chromium (VI) molecular imprinting material, a preparation method and an application thereof.
Background
The information in this background section is disclosed only to enhance an understanding of the general background of the disclosure and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.
Chromium is one of the elements widely present in the environment, and has a good industrial application value due to a good electronic structure. The hexavalent chromium compounds generally used are potassium dichromate, sodium dichromate, chromium trioxide, ammonium dichromate, zinc chromate, lead chromate, and the like. Potassium dichromate, sodium dichromate, chromium trioxide, ammonium dichromate have been widely used as oxidizing agents in organic synthesis. Potassium dichromate and sodium dichromate have been used in the production of tanning agents and in the tanning of leather. Chromium pollution in water is mainly derived from hexavalent chromium, which enters human bodies through respiratory tracts, digestive tracts, skins and mucous membranes and can cause gastrointestinal diseases, anemia and the like. Chromium compounds are harmful to soil, crops and aquatic organisms, and chromium-containing wastewater is accumulated in soil, so that the soil is hardened and the yield of crops is reduced.
Common treatment methods for chromium-containing wastewater include biological methods, chemical methods and physical and chemical methods. The biological method is to carry out reduction enrichment activity on hexavalent chromium by utilizing the adsorption action of microorganisms and metabolic products thereof, the catalytic conversion action of enzyme and the flocculation action; the current research is still in the laboratory stage and is not popularized and applied on a large scale. The chemical methods include reduction precipitation, photocatalysis, electrolytic reduction, etc., and have disadvantages that: the reagent demand is large, the energy consumption is high, the treatment cost is high, and the like. The physicochemical methods include a membrane separation method, an ion exchange method, and an adsorption method. The molecular imprinting material is a polymer which is synthesized by a molecular imprinting technology and has specific recognition and selective adsorption on specific target molecules and structural analogues thereof. However, cr exists in the prior art about chromium (VI) molecularly imprinted materials and preparation methods thereof 6+ Low removal rate, poor selectivity, low adsorption capacity and the like.
Disclosure of Invention
In view of the background technologies, the purpose of the present disclosure is to provide a chromium (vi) molecularly imprinted polymer, and a preparation method and an application thereof, and the obtained chromium (vi) molecularly imprinted polymer has high yield, high removal rate, good selectivity, high adsorption capacity, and good application prospects in chromium (vi) containing wastewater treatment.
Specifically, the following technical scheme is adopted in the disclosure:
in a first aspect of the present disclosure, there is provided a method for preparing a chromium (vi) molecularly imprinted material, the method comprising the steps of:
(1) Preparing a potato starch graft copolymer by using gelatinized potato starch and methacrylamide as raw materials, persulfate as an initiator and urea as an auxiliary agent through an aqueous solution polymerization method;
(2) Adding the starch graft copolymer in the step (1) into water, adding alkali to adjust the pH value to 9-10, adding formaldehyde, and heating for reaction; then adjusting the pH value to 11-12, adding dimethylamine, and heating for reaction; precipitating the product with acetone, washing and drying to obtain an aminomethylated modified product of the potato starch graft copolymer;
(3) Taking the aminomethylated modified product of the potato starch graft copolymer in the step (2) as a raw material, taking chromium (VI) as a template molecule, adding a cross-linking agent, and heating and stirring for reaction; and after the reaction is finished, eluting the template molecules by using alkali liquor, eluting the template molecules by using water to be neutral, and drying to obtain the target product, namely the chromium (VI) molecularly imprinted material.
In the step (1), the gelatinized potato starch is prepared by the following method: mixing potato starch and water according to the mass ratio of 1.
Aiming at the purpose of the invention disclosed herein, the application discusses different starch types as reaction raw materials, including glutinous rice starch with high amylopectin content, corn starch with high direct connection content, potato starch with intermediate amylopectin content and the like, through experimental verification, the potato starch is selected as the reaction raw material, the yield of the obtained chromium (VI) molecular imprinting material is high (can be increased by 5-15%), and Cr (VI) is adsorbed 6+ Has good effect and has incomparable advantages with other types of starch.
Before graft copolymerization, potato starch is pasted, the potato starch after swelling is subjected to graft copolymerization reaction more fully, the graft copolymerization effect is more excellent, and the adsorption capacity is larger.
In the step (1), methacrylamide is used as a comonomer, and experiments prove that the chromium (VI) molecularly imprinted material prepared from methacrylamide has good selectivity to chromium (VI) compared with acrylamide.
In the step (1), the specific reaction process comprises: mixing persulfate, urea and water, and fully stirring at 40-50 ℃ until the persulfate, the urea and the water are completely dissolved to obtain a solution I; neutralizing methacrylamide with 30-40 w/w/% sodium hydroxide solution, controlling the neutralization degree to be 70-80%, and obtaining solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1-2 h at 40-50 ℃, washing the obtained product with absolute ethyl alcohol for a plurality of times, and drying to obtain the potato starch graft copolymer.
The ratio of the raw materials needs to be proper to obtain a target product with ideal effect, preferably, the mass ratio of the potato starch, the persulfate, the urea, the water and the methacrylamide is 1: 0.02-0.05: 20 to 100.
The persulfuric acid is potassium persulfate in terms of improving the effect of graft copolymerization.
In the step (2), the specific reaction process is as follows: adding the starch graft copolymer obtained in the step (1) into water, adding alkali to adjust the pH value to 9-10, adding a formaldehyde aqueous solution, and reacting at 60-70 ℃ for 1-2 h; then adjusting the pH value to 11-12, adding dimethylamine aqueous solution, and reacting for 2-4 h at 70-80 ℃.
The metal ion adsorption quantity can be improved only by the modification of certain aminomethylation. Preferably, the mass ratio of the starch graft copolymer to the water to the aqueous formaldehyde solution to the aqueous dimethylamine solution is 1.
Further, the mass fraction of the formaldehyde aqueous solution is 35-40%; the mass fraction of the dimethylamine aqueous solution is 30-40%.
Tests prove that the method improves the final adsorption performance on the hexavalent chromium ions by performing aminomethylation modification on the starch graft copolymer in the step (1), and cannot achieve the purpose by adopting other modifications, such as esterification modification, sulfomethylation modification and the like; tests prove that through esterification modification, the adsorption performance of the material on metal ions is reduced, and the adsorption effect is influenced; the material has larger pores and reduces the Cr content by sulfomethylation modification 6+ Selectivity of (2).
In the step (3), the specific reaction process is as follows: soaking the aminomethylated modified product of the potato starch graft copolymer in a chromium (VI) solution with the mass concentration of 1-2 g/L for 5-12 h at the soaking temperature of 25-40 ℃, adding a glutaraldehyde aqueous solution, stirring and reacting at 50-60 ℃ for 12-24 h, eluting template molecules by using a sodium hydroxide solution after the reaction is finished, eluting the template molecules to be neutral by using water, and drying in vacuum to obtain the target product.
Preferably, the use mass of the glutaraldehyde aqueous solution is 1-3% of the aminomethylated modified product of the potato starch graft copolymer; the mass concentration of the glutaraldehyde water solution is 40-50%.
In a second aspect of the present disclosure, a chromium (vi) molecularly imprinted polymer material prepared by the above method is provided.
In a third aspect of the disclosure, there is provided a use of the above chromium (vi) molecularly imprinted material in treatment of chromium (vi) -containing wastewater.
Compared with the related technologies known by the inventor, one technical scheme of the disclosure has the following beneficial effects:
the method comprises the steps of firstly preparing a potato starch graft copolymer by adopting an aqueous solution polymerization method, and providing a good polymer adsorption carrier for chromium (VI); performing aminomethylation modification on the starch graft copolymer, and testing and verifying that the adsorption capacity of the starch graft copolymer on metal ions is improved; and then, crosslinking the aminomethylated and modified starch graft copolymerization product by taking chromium (VI) as a template molecule to obtain the chromium (VI) molecularly imprinted polymer material with high chromium (VI) selective adsorption performance.
The prepared chromium (VI) molecularly imprinted material has high adsorption removal rate and high chemical stability, can selectively adsorb chromium (VI), recover chromium (VI) metal ions from wastewater, and can be repeatedly recycled after being eluted.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to be construed as limiting the disclosure.
FIG. 1 is a plot of chromium (VI) removal for the materials of example 1, comparative example 1, and comparative example 2.
FIG. 2 is a material pair Cr of example 1 and comparative example 3 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The adsorption performance of (3).
FIG. 3 is a material pair Cr of example 1 and comparative example 4 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The adsorption performance of (3).
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.
In order to make the technical solutions of the present disclosure more clearly understood by those skilled in the art, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments.
Example 1
A preparation method of a chromium (VI) molecularly imprinted material comprises the following steps:
(1) Adding 50g of potato starch into 1000mL of distilled water, fully stirring, stirring and pasting at 75 ℃ for 45min, and cooling to 50 ℃ to obtain pasted potato starch; mixing 0.5g of potassium persulfate, 1.25g of urea and 1200mL of distilled water, and fully stirring at 50 ℃ until the potassium persulfate and the urea are completely dissolved to obtain a solution I; neutralizing 60g of methacrylamide by using 30w/w/% of sodium hydroxide solution, and controlling the neutralization degree to be 75% to obtain solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1.5h at 50 ℃, washing the obtained product with absolute ethyl alcohol for 2 times, drying in vacuum, grinding, and sieving by a 100-mesh sieve to obtain the potato starch graft copolymer.
(2) Adding 10g of the potato starch graft copolymer obtained in the step (1) into 1000mL of distilled water, adding a sodium hydroxide solution to adjust the pH to 9, adding 1mL of 35w/w% formaldehyde water solution, and reacting at 60 ℃ for 1.5h; then adjusting the pH value to 11, adding 1mL of 40w/w% dimethylamine aqueous solution, and reacting for 3h at 80 ℃; and precipitating the product by using acetone, washing, drying in vacuum, and grinding to obtain the aminomethylated modified product of the potato starch graft copolymer.
(3) Soaking 5g of the potato starch graft copolymer aminomethylated modified product in the step (2) in 50mL of chromium (VI) solution with the mass concentration of 1.5g/L overnight at the soaking temperature of 35 ℃, adding 0.1mL of 50w/w/% glutaraldehyde aqueous solution, stirring and reacting at 55 ℃ for 20h, eluting template molecules by using a sodium hydroxide solution after the reaction is finished, eluting the template molecules to be neutral by using water, and drying in vacuum to obtain the target product, namely the chromium (VI) molecularly imprinted material.
Example 2
A preparation method of a chromium (VI) molecularly imprinted material comprises the following steps:
(1) Adding 50g of potato starch into 1000mL of distilled water, fully stirring, stirring and pasting at 80 ℃ for 50min, and cooling to 45 ℃ to obtain pasted potato starch; mixing 0.75g of potassium persulfate, 2g of urea and 1500mL of distilled water, and fully stirring at 45 ℃ until the potassium persulfate and the urea are completely dissolved to obtain a solution I; neutralizing 80g of methacrylamide by using 40w/w/% of sodium hydroxide solution, and controlling the neutralization degree to be 80% to obtain solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1.2h at 45 ℃, washing the obtained product with absolute ethyl alcohol for 2 times, drying in vacuum, grinding, and sieving by a 100-mesh sieve to obtain the potato starch graft copolymer.
(2) Adding 10g of the potato starch graft copolymer obtained in the step (1) into 1200mL of distilled water, adding a sodium hydroxide solution to adjust the pH value to 10, adding 0.8g of 35w/w% formaldehyde water solution, and reacting at 70 ℃ for 1h; then adjusting the pH value to 12, adding 0.8g of 40w/w% dimethylamine aqueous solution, and reacting for 3.5h at 75 ℃; and precipitating the product by using acetone, washing, drying in vacuum, and grinding to obtain the aminomethylated modified product of the potato starch graft copolymer.
(3) Soaking 5g of the potato starch graft copolymer aminomethylated modified product obtained in the step (2) in a chromium (VI) solution with the mass concentration of 2g/L overnight at the soaking temperature of 40 ℃, adding 0.12mL50w/w/% glutaraldehyde aqueous solution, stirring and reacting for 24 hours at the temperature of 60 ℃, eluting template molecules by using a sodium hydroxide solution after the reaction is finished, eluting to be neutral by using water, and drying in vacuum to obtain the target product, namely the chromium (VI) molecularly imprinted material.
Example 3
A preparation method of a chromium (VI) molecularly imprinted material comprises the following steps:
(1) Adding 50g of potato starch into 1000mL of distilled water, fully stirring, stirring and gelatinizing at 80 ℃ for 30min, and cooling to 50 ℃ to obtain gelatinized potato starch; mixing 0.65g of potassium persulfate, 2g of urea and 2000mL of distilled water, and fully stirring at 50 ℃ until the potassium persulfate and the urea are completely dissolved to obtain a solution I; neutralizing 90g of methacrylamide by using 30w/w/% of sodium hydroxide solution, and controlling the neutralization degree to be 80% to obtain solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1h at 50 ℃, washing the obtained product with absolute ethyl alcohol for 2 times, drying in vacuum, grinding, and sieving by a 100-mesh sieve to obtain the potato starch graft copolymer.
(2) Adding 10g of the potato starch graft copolymer obtained in the step (1) into 800mL of distilled water, adding a sodium hydroxide solution to adjust the pH value to 12, adding 1.2mL of 35w/w% formaldehyde water solution, and reacting at 60 ℃ for 1.5h; then adding 1.2g of sodium bisulfite, and reacting for 3.5h at 80 ℃; and precipitating the product by using acetone, washing, drying in vacuum, and grinding to obtain the aminomethylated modified product of the potato starch graft copolymer.
(3) Soaking 5g of the potato starch graft copolymer aminomethylated modified product in the step (2) in 45mL of chromium (VI) solution with the mass concentration of 1.5g/L overnight at the soaking temperature of 37 ℃, adding 0.15mL of 50w/w/% glutaraldehyde aqueous solution, stirring and reacting at 50 ℃ for 24h, eluting the template molecule by using a sodium hydroxide solution after the reaction is finished, eluting the template molecule to be neutral by using water, and drying in vacuum to obtain the target product, namely the chromium (VI) molecularly imprinted material.
Comparative example 1
Compared with example 1, the potato starch is not gelatinized, and other steps and methods are the same as example 1.
Comparative example 2
The potato starch of example 1 was replaced with corn starch and the other steps and methods were the same as in example 1.
Comparative example 3
A preparation method of a molecularly imprinted material comprises the following steps:
(1) Adding 50g of potato starch into 1000mL of distilled water, fully stirring, stirring and pasting at 75 ℃ for 45min, and cooling to 50 ℃ to obtain pasted potato starch; mixing 0.5g of potassium persulfate, 1.25g of urea and 1200mL of distilled water, and fully stirring at 50 ℃ until the potassium persulfate and the urea are completely dissolved to obtain a solution I; neutralizing 60g of methacrylamide by using 30w/w/% of sodium hydroxide solution, and controlling the neutralization degree to be 75% to obtain solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1.5h at 50 ℃, washing the obtained product with absolute ethyl alcohol for 2 times, drying in vacuum, grinding, and sieving by a 100-mesh sieve to obtain the potato starch graft copolymer.
(2) Adding 10g of the potato starch graft copolymer obtained in the step (1) into 1000mL of distilled water, adding a sodium hydroxide solution to adjust the pH to 9, adding 1mL of 35w/w% formaldehyde water solution, and reacting at 60 ℃ for 1.5h; then adjusting the pH value to 11, adding 1mL of 40w/w% dimethylamine aqueous solution, and reacting for 3h at 80 ℃; and precipitating the product by using acetone, washing and drying in vacuum to obtain a sulfomethylated modified product of the potato starch graft copolymer.
(3) Soaking 5g of the sulfomethylated modified product of the potato starch graft copolymer obtained in the step (2) in 50mL of a chromium (VI) solution with the mass concentration of 1.5g/L overnight at the soaking temperature of 35 ℃, adding 0.1mL of 50w/w/% glutaraldehyde aqueous solution, stirring and reacting at 55 ℃ for 20h, eluting the template molecule by using a sodium hydroxide solution after the reaction is finished, eluting the template molecule by using water to be neutral, and drying in vacuum.
Comparative example 4
The methacrylamide in example 1 was replaced by acrylamide and the other steps and methods were the same as in example 1.
Experimental example: examples1. Comparative examples 1 to 2 verification test for adsorption Properties of chromium (VI)
Accurately weighing 10mg of the chromium (VI) molecularly imprinted material prepared in the example 1, adding the material into a chromium (VI) solution with the mass concentration of 400mg/L, adjusting the temperature to room temperature by using a constant-temperature oscillator, carrying out oscillation adsorption in the constant-temperature oscillator at the rotation speed of 150rpm for 180min, filtering the solution by using filter paper, measuring the initial and residual chromium (VI) concentrations of the solution, and calculating the removal rate by using a formula (1).
E＝(C 0 -C e )/C 0 ×100％ (1)
In the formula, E represents the removal rate,%; c 0 Represents the concentration of chromium (VI) before adsorption, mg/L; c e The concentration of chromium (VI) in the solution after adsorption is expressed in mg/L.
The chromium (vi) removal rates of the three materials of example 1, comparative example 1 and comparative example 2 are shown in fig. 1.
As can be seen from fig. 1, the adsorption equilibrium time of the molecularly imprinted material of example 1 is the shortest as the adsorption time is prolonged, and the adsorption removal rate and the adsorption capacity are the highest, as high as 99% or more, compared to the materials of comparative examples 1 and 2.
Experimental example: example 1 and comparative example 3 verification test for selective adsorption Performance of chromium (VI)
Taking 50mL of Cr 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The mixed solution was adjusted to pH 7 at 40mg/L, and 10mg of the materials of example 1 and comparative example 3 were added to conduct adsorption at room temperature for 1 hour. FIG. 2 is a material pair Cr of example 1 and comparative example 3 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The adsorption performance of (3).
As can be seen from FIG. 2, the molecularly imprinted material of example 1 was used for Cr 6+ The material of comparative example 3 is excellent in selective adsorption to Cr 6+ And Ni 2+ All had some clearance and the selective adsorption was inferior compared to example 1.
Experimental example: example 1 and comparative example 4 for the selective adsorption of chromium (VI)Verification test
Taking 50mL of Cr 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The solutions were mixed at 20mg/L, the pH was adjusted to 7, and 10mg of the materials of example 1 and comparative example 3 were added to the solution, and adsorption was carried out at room temperature for 1 hour. FIG. 3 is a material pair Cr of example 1 and comparative example 4 6+ 、Zn 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ The adsorption performance of (3).
As can be seen from FIG. 3, the molecularly imprinted material of example 1 was aligned with Cr 6+ The selective adsorption was very excellent, while the material of comparative example 4 had a certain adsorption to each metal ion.
The above embodiments are preferred embodiments of the present disclosure, but the embodiments of the present disclosure are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present disclosure should be regarded as equivalent replacements within the scope of the present disclosure.

Claims (10)

1. A preparation method of a chromium (VI) molecular imprinting material is characterized by comprising the following steps:
(1) Preparing a potato starch graft copolymer by using gelatinized potato starch and methacrylamide as raw materials, persulfate as an initiator and urea as an auxiliary agent through an aqueous solution polymerization method;
(2) Adding the starch graft copolymer in the step (1) into water, adding alkali to adjust the pH value to 9-10, adding formaldehyde, and heating for reaction; then adjusting the pH value to 11-12, adding dimethylamine, and heating for reaction; precipitating the product with acetone, washing and drying to obtain an aminomethylated modified product of the potato starch graft copolymer;
(3) Taking the aminomethylated modified product of the potato starch graft copolymer in the step (2) as a raw material, taking chromium (VI) as a template molecule, adding a cross-linking agent, and heating and stirring for reaction; and after the reaction is finished, eluting the template molecules by using alkali liquor, eluting the template molecules by using water to be neutral, and drying to obtain the target product.
2. The method of claim 1, wherein in step (1), the gelatinized potato starch is prepared by the following method: mixing potato starch and water according to the mass ratio of 1.
3. The method according to claim 1, wherein in the step (1), the specific reaction process comprises: mixing persulfate, urea and water, and fully stirring at 40-50 ℃ until the persulfate, the urea and the water are completely dissolved to obtain a solution I; neutralizing methacrylamide by using 30-40 mass percent sodium hydroxide solution, and controlling the neutralization degree to be 70-80% to obtain solution II; uniformly mixing the gelatinized potato starch, the solution I and the solution II, reacting for 1-2 h at 40-50 ℃, washing the obtained product with absolute ethyl alcohol for a plurality of times, and drying to obtain the potato starch graft copolymer.
4. The preparation method according to claim 1, wherein in the step (1), the mass ratio of the potato starch, the persulfate, the urea, the water and the methacrylamide is 1: 0.02-0.05: 20 to 100.
5. The process according to claim 1, wherein in the step (1), the persulfate is potassium persulfate.
6. The method according to claim 1, wherein in the step (2), the specific reaction process is: adding the starch graft copolymer in the step (1) into water, adding alkali to adjust the pH value to 9-10, adding a formaldehyde aqueous solution, and reacting at 60-70 ℃ for 1-2 h; then adjusting the pH value to 11-12, adding dimethylamine aqueous solution, and reacting for 2-4 h at 70-80 ℃.
7. The preparation method according to claim 1, wherein in the step (2), the mass ratio of the starch graft copolymer to the aqueous solution of formaldehyde to the aqueous solution of dimethylamine is 1; the mass fraction of the formaldehyde aqueous solution is 35-40%; the mass fraction of the dimethylamine aqueous solution is 30-40%.
8. The method according to claim 1, wherein in the step (3), the specific reaction process is: soaking a potato starch graft copolymer aminomethylated modified product in a chromium (VI) solution with the mass concentration of 1-2 g/L for 5-12 h at the soaking temperature of 25-40 ℃, adding a glutaraldehyde aqueous solution, stirring and reacting at 50-60 ℃ for 12-24 h, eluting template molecules by using a sodium hydroxide solution after the reaction is finished, eluting the template molecules to be neutral by using water, and drying in vacuum to obtain a target product;
the using amount of the glutaraldehyde aqueous solution is 1-3% of the aminomethylated modified product of the potato starch graft copolymer; the mass concentration of the glutaraldehyde water solution is 40-50%.
9. A chromium (vi) molecularly imprinted polymeric material prepared by the method of any one of claims 1 to 8.
10. The use of the chromium (vi) molecularly imprinted material of claim 9 in the treatment of chromium (vi) -containing wastewater.
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CN111499800A (en) * 2020-05-19 2020-08-07 河南水利与环境职业学院 Zearalenone surface imprinted polymer, synthesis method thereof and application thereof in grain detection

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