Cyclodextrin modified nylon membrane material as well as preparation method and application thereof

Abstract

The invention relates to the field of environmental pollutant detection, in particular to a cyclodextrin modified nylon membrane material as well as a preparation method and application thereof. The cyclodextrin modified nylon membrane material provided by the invention comprises a nylon membrane and beta-cyclodextrin grafted on the nylon membrane. The characteristic that the surface of a nylon membrane (polyamide membrane) is rich in acylamino and a small amount of hydroxyl is utilized, the groups are used as active groups to form ether bonds with hydroxyl on beta-cyclodextrin molecules, so that the beta-cyclodextrin molecules are grafted to the surface of the nylon membrane, and the cyclodextrin modified nylon membrane material is obtained. The material has excellent selective adsorbability on polycyclic aromatic hydrocarbon in water, and can be directly used for spectrum detection after being used as a solid-phase extraction agent for adsorbing the polycyclic aromatic hydrocarbon in the water, so that rapid quantitative detection of the polycyclic aromatic hydrocarbon is realized.

Description

Technical Field

[0001] The invention relates to the field of environmental pollutant detection, and in particular to a cyclodextrin-modified nylon membrane material and a preparation method and application thereof. Background Art

[0002] Polycyclic aromatic hydrocarbons (PAHs) are a class of organic pollutants composed of multiple benzene rings, which are widely present in emissions such as fuel combustion, petrochemicals, motor vehicle exhaust and industrial wastewater. PAHs are highly carcinogenic, mutagenic and difficult to degrade. They can exist in the environment for a long time, especially in water bodies, and they pose a serious threat to ecosystems and human health. Therefore, the development of rapid and sensitive PAHs detection methods is of great significance for environmental monitoring and pollution control.

[0003] Traditional PAHs detection methods mainly rely on technologies such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography (HPLC). Although these methods can provide highly sensitive and accurate detection results, the sample pretreatment process is complex, time-consuming and costly, and usually requires the use of expensive instruments and equipment, and is not suitable for rapid on-site detection. To this end, researchers have explored solid-phase extraction methods based on membrane materials to selectively enrich PAHs in water samples to simplify the detection process. However, existing membrane materials mainly use polyacrylonitrile membranes, polyvinylidene fluoride membranes, and cellulose membranes to directly enrich PAHs, and their selective adsorption capacity for PAHs still needs to be improved. Summary of the invention

[0004] To solve the above problems, the present invention provides a cyclodextrin modified nylon membrane material and its preparation method and use. The membrane material provided by the present invention has strong selective adsorption to polycyclic aromatic hydrocarbons (PAHs). When it is used in solid phase spectroscopy technology, it can selectively enrich PAHs and realize rapid quantitative detection of PAHs.

[0005] The invention provides a cyclodextrin modified nylon membrane material, comprising a nylon membrane and beta-cyclodextrin grafted onto the nylon membrane.

[0006] Optionally, the grafting amount of β-cyclodextrin is 1.0-1.4 mg / cm 2 .

[0007] Optionally, the nylon membrane has a thickness of 50-150 μm and a pore size of 0.1-0.45 μm.

[0008] The present invention also provides a method for preparing the cyclodextrin-modified nylon membrane material described in the above technical solution, comprising the following steps:

[0009] The nylon membrane is immersed in a beta-cyclodextrin solution to carry out a grafting modification reaction to obtain a cyclodextrin-modified nylon membrane material.

[0010] Optionally, the concentration of the β-cyclodextrin solution is 1-10 g / L, and the pH of the cyclodextrin solution is 4.5-6.0.

[0011] Optionally, the temperature of the grafting modification reaction is 25-60° C., and the reaction time is 2-6 hours.

[0012] Optionally, the preparation method further comprises, before immersing the nylon membrane in the β-cyclodextrin solution, subjecting the nylon membrane to an activation treatment, wherein the activation treatment comprises at least one of an oxidant treatment and a plasma treatment.

[0013] The present invention also provides the use of the cyclodextrin-modified nylon membrane material described in the above technical solution or the cyclodextrin-modified nylon membrane material obtained by the preparation method described in the above technical solution in the removal or detection of polycyclic aromatic hydrocarbons.

[0014] The present invention also provides a method for detecting polycyclic aromatic hydrocarbons in water, comprising the following steps:

[0015] The cyclodextrin-modified nylon membrane material described in the above technical solution or the cyclodextrin-modified nylon membrane material obtained by the preparation method described in the above technical solution is used to filter the water body to be tested containing polycyclic aromatic hydrocarbons to obtain the membrane material to be tested.

[0016] The filter surface of the membrane material to be tested is subjected to spectral detection to obtain the characteristic peak intensity.

[0017] The content of the polycyclic aromatic hydrocarbons is obtained according to the characteristic peak intensity and the standard curve of the polycyclic aromatic hydrocarbons.

[0018] Optionally, the filtration flow rate is 0.01-1.20 mL / (min·cm 2 ); the spectral detection is ultraviolet-visible spectral detection or fluorescence spectral detection, the wavelength range of the ultraviolet-visible spectral detection is 200-400nm, the excitation light wavelength of the fluorescence spectral detection is 280-395nm, and the spectral scanning range is 300-500nm.

[0019] The present invention provides a cyclodextrin modified nylon membrane material, comprising a nylon membrane and β-cyclodextrin grafted onto the nylon membrane. The present invention utilizes the characteristics of the nylon membrane (polyamide membrane) surface being rich in amide groups and a small amount of hydroxyl groups, and uses these groups as active groups to form ether bonds with the hydroxyl groups on the β-cyclodextrin molecules, thereby grafting the β-cyclodextrin molecules onto the nylon membrane surface to obtain a cyclodextrin modified nylon membrane material. The material has excellent selective adsorption for PAHs in water bodies, and after being used as a solid phase extractant to adsorb PAHs in water bodies, it can be directly used for spectral detection, thereby realizing rapid quantitative detection of PAHs. The results of the embodiments of the present application show that the cyclodextrin modified nylon membrane material of the present invention is used as a solid phase extractant in combination with ultraviolet-visible light spectral detection, and the concentration range that can be used for detection is 5-50 mg / L, and combined with fluorescence spectral detection, the concentration range that can be used for detection is 0.1 ppb-50 ppb.

[0020] The preparation method of the cyclodextrin modified nylon membrane material provided by the invention is simple, easy to operate, does not require complicated equipment, has low cost, and has good industrial application prospects.

[0021] The present invention also provides the use of cyclodextrin modified nylon membrane material in the removal or detection of PAHs. The membrane material has excellent selective adsorption of PAHs, can effectively remove PAHs in water, and plays a role in purifying water. At the same time, based on its excellent selective adsorption, it can be used in solid phase spectroscopy technology.

[0022] The present invention also provides a method for detecting PAHs in water using the cyclodextrin-modified nylon membrane material. After filtering the water using the β-cyclodextrin-modified nylon membrane material, the filtration surface of the membrane material can be directly detected by spectral technology (i.e., when filtering the water, the side where the water enters the cyclodextrin-modified nylon membrane material), and then the concentration of PAHs in the water can be obtained by characteristic peak intensity and standard curve. The method directly detects the filtration surface of the membrane material without elution, that is, it avoids the elution step of the traditional solid phase chromatography, simplifies the detection process, and has high sensitivity. The results of the embodiments of the present application show that the detection method provided by the present invention directly performs spectral detection on the filtration surface of the membrane material after filtering the water to be tested, and accurate concentration results can be obtained, with an error of less than 2%, and there is basically no interference from the matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will be apparent from the following description of preferred embodiments and accompanying drawings which illustrate the subject matter of the present invention and its use, in which:

[0024] Figure 1 This is the infrared spectrum detection diagram of the cyclodextrin modified nylon membrane material obtained in Example 1.

[0025] Figure 2 This is the fluorescence spectrum of the standard solution of benzo[a]pyrene.

[0026] Figure 3 is the standard curve of benzo[a]pyrene. DETAILED DESCRIPTION

[0027] The present invention will be described below by specific embodiments, and it will be appreciated by those skilled in the art that the following specific embodiments are only for illustrative purposes, and do not limit the scope of the present invention in any way. In addition, in the following embodiments, unless otherwise specified, the reagents and equipment used are all commercially available. If in the following embodiments, specific treatment conditions and treatment methods are not clearly described, then conditions and methods known in the art can be adopted to process.

[0028] The invention provides a cyclodextrin modified nylon membrane material, comprising a nylon membrane and beta-cyclodextrin grafted onto the nylon membrane.

[0029] In the cyclodextrin-modified nylon membrane material of the present invention, the nylon membrane as a substrate has good mechanical strength and chemical stability, and the surface is rich in amide groups and a small amount of hydroxyl groups; and β-cyclodextrin is a natural cyclic oligosaccharide with a hydrophobic inner cavity and a hydrophilic outer wall structure (containing multiple hydroxyl groups). The inventors found in the experiment that the cage structure of β-cyclodextrin can form inclusion complexes with polycyclic aromatic hydrocarbons (PAHs), and there is an inclusion complex (hydrophobic interaction and van der Waals force) between the hydrophobic inner cavity of the β-cyclodextrin molecule and the PAHs molecule, showing good molecular recognition and selective adsorption capacity; based on this, β-cyclodextrin is reacted with the amide groups and hydroxyl groups on the surface of the nylon membrane through hydroxyl groups to form ether bonds, thereby grafting β-cyclodextrin on the surface of the nylon membrane to obtain a cyclodextrin-modified nylon membrane material. During the experiment, the inventors found that the cyclodextrin-modified nylon membrane material has a better adsorption of PAHs than other membrane materials modified by cyclodextrin.

[0030] In the present invention, the grafting amount of β-cyclodextrin determines the adsorption amount of PAHs in the water body. The larger the grafting amount of β-cyclodextrin, the larger the amount of PAHs that can be adsorbed. Those skilled in the art can adjust the grafting amount of cyclodextrin by adjusting the concentration of β-cyclodextrin or the time of grafting modification when preparing the cyclodextrin-modified nylon membrane. Those skilled in the art can select a suitable grafting amount of β-cyclodextrin according to the actual use, the amount of PAHs in the water body to be treated, the treatment efficiency and economy, etc.

[0031] In some embodiments of the present invention, the grafting amount of β-cyclodextrin is 1.0-1.4 mg / cm 2 , specifically 1.0 mg / cm 2, 1.1mg / cm 2 , 1.2mg / cm 2 , 1.3mg / cm 2 and 1.4 mg / cm 2 , and any value between the above values. In the present invention, the cyclodextrin-modified nylon membrane material with the above-mentioned range of grafting amount has a more excellent adsorption capacity and can quickly adsorb PAHs at a higher filtration rate, while the grafting amount below the above range requires a lower filtration rate to adsorb PAHs, which is relatively time-consuming; too high a grafting amount will increase the cost and affect the filtration efficiency.

[0032] In some embodiments of the present invention, the thickness of the nylon membrane is 50-150 μm, preferably 90-110 μm, and specifically can be 50 μm, 70 μm, 90 μm, 100 μm, 110 μm, 130 μm and 150 μm, and any value between the above values; the pore size of the nylon membrane is 0.1-0.45 μm, preferably 0.20-0.25 μm, and specifically can be 0.2 μm, 0.22 μm, 0.25 μm, 0.4 μm and 0.45 μm, and any value between the above values. In the present invention, the above thickness and pore size can ensure that the nylon membrane has better mechanical properties and adsorption capacity.

[0033] The present invention also provides a method for preparing the cyclodextrin-modified nylon membrane material described in the above technical solution, comprising the following steps:

[0034] The nylon membrane is immersed in a beta-cyclodextrin solution to carry out a grafting modification reaction to obtain a cyclodextrin-modified nylon membrane material.

[0035] In some embodiments of the present invention, the nylon membrane is cleaned before use to remove impurities. For the nylon membrane that is relatively clean, it can be directly used to prepare the cyclodextrin modified nylon membrane material without cleaning. The present invention does not specifically limit the solvent and method used for cleaning, as long as it can remove impurities on the surface of the nylon membrane; in some embodiments of the present invention, the cleaning solvent is an ethanol aqueous solution with a volume concentration of 50%; in the embodiment of the present invention, the ethanol aqueous solution is prepared by mixing deionized water and anhydrous ethanol in a volume ratio of 1:1.

[0036] In some embodiments of the present invention, the preparation method further comprises, before immersing the nylon membrane in the β-cyclodextrin solution, subjecting the nylon membrane to an activation treatment, wherein the activation treatment comprises at least one of an oxidant treatment and a plasma treatment. In the present invention, the activation treatment can generate more hydroxyl and carboxyl groups on the surface of the nylon membrane to further improve the high reactivity of the nylon membrane.

[0037] In some embodiments of the present invention, the oxidant treatment comprises the steps of:

[0038] The nylon membrane is immersed in an oxidant aqueous solution to perform an activation reaction to obtain an activated nylon membrane.

[0039] In some embodiments of the present invention, the oxidant in the aqueous oxidant solution is at least one of potassium persulfate and hydrogen peroxide; when the oxidant is potassium persulfate, the concentration of the aqueous oxidant solution is 5-10 g / L; when the oxidant is hydrogen peroxide, the concentration of the aqueous oxidant solution is 3-6% (v / v); the temperature of the activation reaction is 40-60°C, preferably 50°C, and the time is 30-60 min, preferably 45 min.

[0040] In some embodiments of the present invention, after the activation reaction is completed, the activated nylon membrane is dried to obtain an activated nylon membrane.

[0041] In some embodiments of the present invention, the conditions for the plasma treatment are: the gas used is oxygen; the power is 30-100 W, preferably 50 W; the gas pressure is 10-100 Pa, preferably 50 Pa; and the time is 2-10 min, preferably 5 min.

[0042] In the present invention, the solvent in the β-cyclodextrin solution can fully dissolve cyclodextrin. In some embodiments of the present invention, the solvent of the cyclodextrin solution is water, methanol, methanol aqueous solution, ethanol aqueous solution, isopropanol or isopropanol aqueous solution. In some embodiments of the present invention, the volume ratio of ethanol to water in the ethanol aqueous solution is 0.8-1.2:1, specifically 0.8:1, 0.9:1, 1:1, 1.1:1 and 1.2:1, and any ratio between the above ratios. The above solvent can ensure that cyclodextrin can be fully dissolved.

[0043] In some embodiments of the present invention, the concentration of the β-cyclodextrin solution is 1-10 g / L, preferably 4-6 g / L, specifically 1 g / L, 3 g / L, 4.5 g / L, 4.8 g / L, 5 g / L, 7 g / L, 9 g / L and 10 g / L and any value between the above values. In the present invention, those skilled in the art can select a suitable concentration as needed. Specifically, a cyclodextrin solution with a lower concentration has higher stability and lower cost, while a cyclodextrin solution with a higher concentration can complete the grafting modification of the nylon membrane faster and improve production efficiency. The cyclodextrin solution in the above preferred concentration range has the advantages of good stability and moderate grafting modification rate, and can achieve the aforementioned optimal grafting amount.

[0044] In some embodiments of the present invention, the pH of the β-cyclodextrin solution is 4.5-6.0, specifically 4.5, 5.0, 5.5, 6.0 or any value therebetween. The above pH can enhance the solubility of cyclodextrin without significantly affecting the chemical stability of the nylon membrane.

[0045] In some embodiments of the present invention, the pH of the β-cyclodextrin solution is adjusted by adding an acid; the acid includes at least one of an inorganic acid and an organic acid; the inorganic acid may specifically be at least one of hydrochloric acid, nitric acid and phosphoric acid; the concentration of the hydrochloric acid is preferably 0.01-0.1M, the concentration of the nitric acid is preferably 0.01-0.1M, and the concentration of the phosphoric acid is preferably 0.01-0.05M, and the inorganic acid at the above concentrations will not damage the inorganic membrane; the organic acid may be at least one of citric acid, acetic acid and lactic acid, and the concentration of the citric acid is preferably 0.05-0.1M, the concentration of the acetic acid is preferably 0.01-0.1M, and the concentration of the lactic acid is preferably 0.01-0.05M, and the organic acid at the above concentrations will cause less damage to the nylon membrane.

[0046] In some embodiments of the present invention, the temperature of the grafting modification reaction is 25-60°C, preferably 35-45°C, and specifically can be 25°C, 35°C, 40°C, 50°C and 60°C and any value between the above values; the reaction time is 2-6h, preferably 3-5h, and specifically can be 2h, 3h, 4h and 5h and any value between the above values. In some embodiments of the present invention, before immersing the nylon membrane in the β-cyclodextrin solution, the β-cyclodextrin solution is pre-heated to the temperature of the grafting modification reaction. In the present invention, the above reaction temperature and time can ensure a more complete reaction between cyclodextrin and the nylon membrane.

[0047] In some embodiments of the present invention, the reaction solution is kept in a stirring state during the grafting modification reaction. The present invention has no particular limitation on the stirring speed, as long as the cyclodextrin is evenly distributed in the reaction system and then evenly distributed on the surface of the nylon membrane.

[0048] In some embodiments of the present invention, after the grafting modification reaction is completed, the modified nylon membrane (i.e., the crude cyclodextrin-modified nylon membrane) is preferably taken out from the reaction solution, washed and dried to obtain a cyclodextrin-modified nylon membrane material. In some embodiments of the present invention, the solvent used for the washing is water, preferably deionized water; the present invention does not specifically limit the method of the washing, and the unreacted cyclodextrin molecules on the surface of the modified nylon membrane can be removed and washed to neutrality. In the embodiments of the present invention, the washing is based on the absence of cyclodextrin in the washing liquid and the neutrality. In some embodiments of the present invention, the drying temperature is 40-60°C, specifically 40°C, 45°C, 50°C, 55°C and 60°C and any value between the above values. The present invention does not specifically limit the drying time, and it can be dried to constant weight.

[0049] The present invention also provides the use of the cyclodextrin-modified nylon membrane material described in the above technical solution or the cyclodextrin-modified nylon membrane material obtained by the preparation method described in the above technical solution in the removal or detection of PAHs.

[0050] In some embodiments of the present invention, the detection is solid phase extraction-spectroscopy detection. The present invention has no particular limitation on the specific method of the solid phase extraction-spectroscopy detection, and the cyclodextrin-modified nylon membrane material can be used for the enrichment of PAHs, and then the cyclodextrin-modified nylon membrane material enriched with PAHs is eluted and used for spectral detection, or the cyclodextrin-modified nylon membrane material enriched with PAHs can be directly subjected to spectral detection.

[0051] The present invention also provides a method for detecting PAHs in water, comprising the following steps:

[0052] The cyclodextrin-modified nylon membrane material described in the above technical solution or the cyclodextrin-modified nylon membrane material obtained by the preparation method described in the above technical solution is used to filter the water body to be tested containing PAHs to obtain the membrane material to be tested.

[0053] The filter surface of the membrane material to be tested is subjected to spectral detection to obtain the characteristic peak intensity.

[0054] The content of the PAHs is obtained according to the characteristic peak intensity and the standard curve of PAHs.

[0055] In some embodiments of the present invention, after filtering the water body to be tested using the cyclodextrin-modified nylon membrane, the PAHs in the water body to be tested will be retained on the filter surface of the cyclodextrin-modified nylon membrane (i.e., the side of the water body to be tested entering the cyclodextrin-modified nylon membrane during filtration) through the inclusion complex of cyclodextrin, and the filter surface is directly used for spectral detection to obtain the characteristic peak intensity, and the characteristic peak intensity is combined with the standard curve to obtain the content of PAHs. The above method of the present invention can also distinguish the types of PAHs and identify the specific concentrations of various PAHs in the water body to be tested.

[0056] The present invention has no particular limitation on the specific method of the filtration, as long as the water to be tested can be uniformly passed through the surface of the cyclodextrin-modified nylon membrane to completely adsorb the PAHs in the water to be tested. In some embodiments of the present invention, the flow rate of the filtration is 0.01-1.20 mL / (min·cm 2 ) (i.e., the volume of the water to be tested that passes through the cyclodextrin-modified nylon membrane per unit area per unit time is 0.01-1.20 mL), preferably 0.58-0.81 mL / (min·cm 2 ), specifically 0.01 mL / (min·cm 2 )、0.02mL / (min·cm 2 )、0.03mL / (min·cm 2 )、0.10mL / (min·cm 2 )、0.11mL / (min·cm 2 )、0.12mL / (min·cm 2 )、0.20mL / (min·cm 2 )、0.29mL / (min·cm 2 )、0.58mL / (min·cm 2 )、0.81mL / (min·cm 2 )、1.15mL / (min·cm 2 ) and 1.20mL / (min·cm 2 ) and any value between the above values. In the present invention, the above filtration rate can improve the filtration efficiency while ensuring that PAHs are completely adsorbed, and the preferred filtration range has a more excellent filtration efficiency. In some embodiments of the present invention, the filtration is vacuum filtration, and the flow rate can be controlled by controlling the size of the negative pressure.

[0057] The present invention does not specifically limit the size of the cyclodextrin-modified nylon membrane material. Those skilled in the art can select the size of the cyclodextrin-modified nylon membrane material according to actual needs. However, it should be noted that the size of the cyclodextrin-modified nylon membrane material used to filter the water body to be tested needs to be the same as the size of the cyclodextrin-modified nylon membrane material used to prepare the standard curve.

[0058] The present invention does not have any special limitation on the volume of the water body to be tested. Those skilled in the art can adjust it according to the test situation. It can be the same as or different from the volume of the standard solution used in preparing the standard curve. When the volume of the water body to be tested is the same as the volume of the standard solution used in preparing the standard curve, the concentration of the water body to be tested can be obtained by directly corresponding the characteristic peak intensity with the characteristic peak intensity on the standard curve. When the volume of the water body to be tested is different from the volume of the standard solution used in preparing the standard curve, it is necessary to first correspond the characteristic peak intensity with the characteristic peak intensity on the standard curve to obtain the concentration when the volume is the same as that of the standard solution (i.e., the concentration when the PAHs in the water body to be tested is dissolved in a water body with the same volume as the standard solution), and then convert it into the concentration of the water body to be tested.

[0059] In some embodiments of the present invention, the spectral detection is ultraviolet-visible spectral detection or fluorescence spectral detection.

[0060] In some embodiments of the present invention, the scanning wavelength range of the ultraviolet-visible spectrum detection is 200-400nm, and the concentration range of the ultraviolet-visible spectrum detection is 5-50mg / L, which is usually used for qualitative detection. In the ultraviolet-visible spectrum detection, the characteristic absorption peak positions of each PAHs are as follows: benzo[a]pyrene 252nm, naphthalene 275nm, phenanthrene 290nm, fluorene 303nm, anthracene 340nm, and fluoranthene 320nm.

[0061] In some embodiments of the present invention, the excitation light wavelength of the fluorescence spectrum detection is 280-395nm, specifically 280nm, 295nm, 300nm, 375nm or 395nm, and the spectral scanning range is 300-500nm; the concentration range of the fluorescence spectrum detection is 0.1ppb-50ppb, which is mainly used for quantitative detection; when the concentration of the water body to be tested is too high, the water body to be tested can be diluted for testing. This detection method can be used for PAHs concentration testing of most wastewater bodies.

[0062] The technical scheme of the present invention will be described clearly and completely below in conjunction with the accompanying drawings and embodiments. The embodiments of the present application are only used as examples, and all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0063] Example 1

[0064] A circular nylon membrane with a diameter of 47 mm, a thickness of 100 μm, and a pore size of 0.2 μm was washed in an ethanol aqueous solution (prepared in a volume ratio of deionized water to ethanol of 1:1) for 5 minutes, and then dried at 50° C. for 2 hours to obtain a clean nylon membrane.

[0065] β-cyclodextrin was dissolved in an ethanol aqueous solution with a volume concentration of 50%, and the pH of the resulting solution was adjusted to 5.5 using a 0.01 M acetic acid aqueous solution to obtain a cyclodextrin solution with a concentration of 5 g / L.

[0066] The cyclodextrin solution was heated to 40° C., and then the clean nylon membrane was immersed in the cyclodextrin solution. The grafting modification reaction was carried out for 4 hours under stirring conditions, and a crude cyclodextrin-modified nylon membrane was obtained in the reaction solution.

[0067] The crude cyclodextrin-modified nylon membrane was taken out, washed with deionized water until the washing liquid was free of cyclodextrin and neutral, and then dried at 50° C. for 2 h to obtain a cyclodextrin-modified nylon membrane material.

[0068] By weighing the weight of the nylon membrane before and after modification, the cyclodextrin grafting amount in the cyclodextrin-modified nylon membrane material was calculated to be 1.0 mg / cm 2 .

[0069] The water contact angles of the nylon membrane used in this example (i.e., the unmodified membrane) and the cyclodextrin-modified nylon membrane material obtained in Example 1 were tested, and the water contact angle of the unmodified membrane was measured to be 80°, while the water contact angle of the cyclodextrin-modified nylon membrane material was 57°, indicating that the hydrophilicity of the cyclodextrin-modified nylon membrane material provided by the present invention is significantly enhanced relative to that of the nylon membrane.

[0070] The cyclodextrin modified nylon membrane material obtained in Example 1 was characterized by Fourier transform infrared spectroscopy (FTIR). Figure 1 As shown, the characteristic peak of ether bond was detected (1050-1150cm-1), indicating that ether bond existed in the cyclodextrin-modified nylon membrane material, indicating that cyclodextrin was grafted onto the nylon membrane material through ether bond.

[0071] Example 2

[0072] The cyclodextrin-modified nylon membrane material was prepared by the method of Example 1, except that the pore size of the nylon membrane was 0.1 μm.

[0073] By weighing the weight of the nylon membrane before and after modification, the cyclodextrin grafting amount in the cyclodextrin-modified nylon membrane material was calculated to be 1.4 mg / cm 2 .

[0074] The cyclodextrin modified nylon membrane material obtained in Example 2 was characterized by Fourier transform infrared spectroscopy (FTIR). The results were similar to those in Example 1. The characteristic peak of ether bond was detected (1050-1150 cm-1). It can be seen that ether bond exists in the cyclodextrin modified nylon membrane material, indicating that cyclodextrin is grafted onto the nylon membrane material through ether bond.

[0075] The water contact angles of the nylon membrane used in this example (i.e., the unmodified membrane) and the cyclodextrin-modified nylon membrane material obtained in Example 2 were tested, and the water contact angle of the unmodified membrane was 80°, while the water contact angle of the cyclodextrin-modified nylon membrane material was 55°, indicating that the hydrophilicity of the cyclodextrin-modified nylon membrane material provided by the present invention is significantly enhanced relative to the nylon membrane. And the cyclodextrin-modified nylon membrane material obtained in Example 2 has a lower water contact angle, indicating that its hydrophilicity is better than that of the cyclodextrin-modified nylon membrane material obtained in Example 1.

[0076] Example 3

[0077] A circular nylon membrane with a diameter of 47 mm, a thickness of 100 μm, and a pore size of 0.2 μm was washed in an ethanol aqueous solution (prepared in a volume ratio of deionized water to ethanol of 1:1) for 5 minutes, and then dried at 50° C. for 2 hours to obtain a clean nylon membrane.

[0078] The clean nylon membrane was immersed in a 10 g / L potassium persulfate aqueous solution at 50°C for 45 minutes of activation treatment, wherein the stirring state was maintained during the activation treatment. The activated nylon membrane was taken out, rinsed with deionized water until neutral, and then dried at 50°C for 2 hours to obtain an activated nylon membrane.

[0079] β-cyclodextrin was dissolved in an ethanol aqueous solution with a volume concentration of 50%, and the pH of the resulting solution was adjusted to 5.5 using a 0.01 M acetic acid aqueous solution to obtain a cyclodextrin solution with a concentration of 6 g / L.

[0080] The cyclodextrin solution was heated to 40° C., and then the clean nylon membrane was immersed in the cyclodextrin solution. The grafting modification reaction was carried out for 4 hours under stirring conditions, and a crude cyclodextrin-modified nylon membrane was obtained in the reaction solution.

[0081] The crude cyclodextrin-modified nylon membrane was taken out, washed with deionized water until the washing liquid was free of cyclodextrin and neutral, and then dried at 50° C. for 2 h to obtain a cyclodextrin-modified nylon membrane material.

[0082] By weighing the weight of the nylon membrane before and after modification, the cyclodextrin grafting amount in the cyclodextrin-modified nylon membrane material was calculated to be 1.2 mg / cm 2 .

[0083] The cyclodextrin-modified nylon membrane material obtained in Example 3 was characterized by Fourier transform infrared spectroscopy (FTIR), and a characteristic peak of ether bond was detected (1050-1150 cm-1), indicating that ether bond existed in the cyclodextrin-modified nylon membrane material, indicating that cyclodextrin was grafted onto the nylon membrane material through ether bond.

[0084] The contact angles of the nylon membrane and the cyclodextrin-modified nylon membrane materials obtained in Examples 1-3 were tested, and the results were: unmodified nylon membrane: 80°, modified: 40°, indicating that the hydrophilicity of the cyclodextrin-modified nylon membrane material provided by the present invention is significantly enhanced relative to that of the nylon membrane.

[0085] In Example 3, the nylon membrane was activated, and the β-cyclodextrin grafting amount of the obtained cyclodextrin-modified nylon membrane material was increased to 1.2 mg / cm 2 This indicates that the activation modification of the nylon membrane improves the reaction activity of the nylon membrane surface, thereby increasing the β-cyclodextrin grafting amount.

[0086] Comparative Example 1

[0087] The method of Example 1 was used to prepare a cyclodextrin-modified polyacrylonitrile membrane, except that the nylon membrane in Example 1 was replaced with a polyacrylonitrile membrane of the same size (thickness 80 μm, pore size 0.22 μm), and the grafting modification reaction time was 5 h.

[0088] The cyclodextrin grafting amount was 1.0 mg / cm 2 .

[0089] Comparative Example 2

[0090] The method of Example 1 was used to prepare a cyclodextrin-modified polyvinylidene fluoride membrane, except that the nylon membrane in Example 1 was replaced with a polyvinylidene fluoride membrane of the same size (thickness of 80 μm, pore size of 0.22 μm), and the grafting modification reaction time was 6 h.

[0091] The cyclodextrin grafting amount was 1.0 mg / cm 2 .

[0092] Comparative Example 3

[0093] The cyclodextrin-modified cellulose membrane was prepared by the method of Example 1, except that the nylon membrane in Example 1 was replaced by a cellulose membrane of the same size (thickness 80 μm, pore size 0.22 μm).

[0094] The cyclodextrin grafting amount was 1.0 mg / cm 2 .

[0095] Comparative Example 4

[0096] The chitosan-modified cellulose membrane was prepared by the method of Example 1, except that the cyclodextrin in Example 1 was replaced by chitosan.

[0097] The cyclodextrin grafting amount was 1.0 mg / cm 2 .

[0098] Performance Testing

[0099] 1. Selective adsorption

[0100] (1) Prepare simulated water containing the following substances and concentrations: 10 mg / L benzo[a]pyrene, 5 mg / L fluorene, and 10 mg / L phenol (non-PAH).

[0101] 100 mL of simulated water was filtered using the cyclodextrin-modified nylon membrane material of Example 1, and the filtration rate was controlled to be 2 mL / min.

[0102] After filtration, the concentration of each substance in the filtrate was detected by liquid chromatography.

[0103] The same method was used to test the selective adsorption of the nylon membrane (i.e., the unmodified nylon membrane) and the cyclodextrin-modified polyacrylonitrile membrane obtained in Comparative Example 1. The test results are shown in Table 1 below:

[0104] Table 1 Selective adsorption test results

[0105]

[0106]

[0107] From the data in the above table, it can be seen that the cyclodextrin modified nylon membrane material obtained in Example 1 completely adsorbed PAHs (benzo[a]pyrene and fluorene) in the water body, and the concentration in the filtrate was lower than the detection limit, and there was no obvious adsorption of phenol, indicating that it has strong selectivity. The unmodified nylon membrane has a low adsorption performance for PAHs, and the removal rates of benzo[a]pyrene and fluorene are 15% and 10%, respectively. The cyclodextrin modified polyacrylonitrile membrane obtained in Comparative Example 1 has a certain adsorption performance for PAHs, but not as good as the cyclodextrin modified nylon membrane material, and the removal rates of benzo[a]pyrene and fluorene are 58% and 44%, respectively.

[0108] (2) Prepare simulated water containing the following substances and concentrations: 10 mg / L benzo[a]pyrene, 10 mg / L phenol, and 10 mg / L tetrachloroethylene.

[0109] The cyclodextrin modified nylon membrane material obtained in Example 1 and the chitosan modified membrane obtained in Comparative Example 4 were used to filter 50 mL of the simulated water at a flow rate of 0.5 mL / min, and then the filtration surface of the filtered membrane was subjected to fluorescence spectrum detection (the excitation light wavelength was 295 nm, and the fluorescence emission spectrum scanning range was 300-500 nm), and the fluorescence intensity of the characteristic emission peak of benzo[a]pyrene was recorded. The concentrations of phenol and tetrachloroethylene in the filtrate were tested by liquid chromatography-ultraviolet / fluorescence detection method, and the removal efficiencies of the two were calculated according to the tested concentrations. The results are shown in Table 2.

[0110] Table 2 Comparison of the selective adsorption of the membrane materials obtained in Example 1 and Comparative Example 4

[0111]

[0112] From the results in the above table, it can be seen that the cyclodextrin modified nylon membrane material (membrane material obtained in Example 1) obtained by the method of the present invention has a higher adsorption intensity for benzo[a]pyrene, and a relatively small removal rate for phenol and tetrachloroethylene, while the chitosan modified membrane material of Comparative Example 4 has a small difference in adsorption of the three substances and lacks specificity. This shows that the cyclodextrin modified nylon membrane material provided by the present invention has a more significant selective adsorption.

[0113] 2. Test of adsorption strength of PAHs

[0114] (1) Comparison of adsorption performance between cyclodextrin-modified nylon membrane material and other cyclodextrin-modified membrane materials

[0115] A benzo[a]pyrene aqueous solution with a concentration of 10 ppb was prepared, and 100 mL of the benzo[a]pyrene aqueous solution was filtered using the cyclodextrin modified membranes obtained in Example 1 and Comparative Examples 1-3, respectively, and the filtration rate was controlled to be 0.6 mL / min.

[0116] After the filtration was completed, the ultraviolet absorbance and fluorescence intensity of the filtration surface of the cyclodextrin modified membrane after filtration were respectively detected by an ultraviolet visible light spectrometer (scanning wavelength of 200-400nm, characteristic absorption peak position of 250nm) and a fluorescence spectrometer (excitation light wavelength of 375nm, emission spectrum scanning range of 300-500nm, emission characteristic peak position of 370nm), and the concentration of residual PAHs in the filtrate was tested by liquid chromatography-fluorescence detection method, and the enrichment efficiency (i.e., removal efficiency) of PAHs was calculated. The results are shown in Table 3.

[0117] Table 3 Adsorption effect of cyclodextrin modified membranes obtained in Example 1 and Comparative Examples 1-3 on PAHs

[0118]

[0119] From the data in the above table, it can be seen that, under the condition of the same cyclodextrin grafting amount, the cyclodextrin modified membrane material prepared by using other membrane materials other than nylon membrane as the base has relatively weak adsorption of PAHs, and the enrichment efficiency of PAHs cannot reach 95%, while the cyclodextrin modified membrane material prepared by using nylon membrane as the base can reach 95% for PAHs enrichment efficiency. This shows that the cyclodextrin modified nylon membrane material has excellent PAHs adsorption performance and can be used to remove PAHs in water.

[0120] (2) Comparison of adsorption performance between cyclodextrin-modified nylon membrane material and chitosan-modified membrane

[0121] A simulated polluted water body was prepared, in which the concentrations of naphthalene, benzo[a]pyrene and fluorene were 5 mg / L, 10 mg / L and 15 mg / L respectively.

[0122] The cyclodextrin modified nylon membrane material obtained in Example 1 and the chitosan modified membrane obtained in Comparative Example 4 were used to filter 100 mL of the above-mentioned simulated water at a flow rate of 10 mL / min. The concentrations of the substances in the simulated water before and after filtration were detected by ultraviolet visible spectrometer (scanning wavelength range 250-350 nm), and the removal rates of the two membranes for the three substances were calculated. The results are shown in Table 4 below:

[0123] Table 4 Removal efficiency of PAHs by cyclodextrin-modified nylon membrane material and chitosan-modified membrane

[0124] Membrane material Naphthalene removal rate Benzo[a]pyrene removal rate Fluorene removal rate Example 1 97％ 94％ 94％ Comparative Example 4 91％ 83％ 78％

[0125] It can be seen from the results in the above table that the cyclodextrin modified nylon membrane material has a stronger adsorption capacity for polycyclic aromatic hydrocarbons than the chitosan modified membrane.

[0126] 3. Adsorption uniformity test

[0127] The cyclodextrin-modified nylon membrane material obtained in Example 1 was used to filter 50 mL of a 10 ppb benzo[a]pyrene aqueous solution at a filtration rate of 2 mL / min.

[0128] The UV-visible spectrometer detects the entire filter surface, the center and the edge of the cyclodextrin-modified nylon membrane material after filtering the benzo[a]pyrene aqueous solution at a scanning wavelength of 200-400nm, and characteristic absorption peaks appear at 250nm, and the absorbances are 0.84, 0.83 and 0.85 respectively. From the above results, it can be seen that PAHs can be uniformly adsorbed on the surface of the cyclodextrin-modified nylon membrane material prepared by the present invention. When detecting, if the window of the UV-visible spectrometer used is small and cannot cover the entire membrane material, it does not affect the final detection result; and when the cyclodextrin-modified nylon membrane material can completely fall within the detection window, the uniformity has no effect on the detection result.

[0129] 4. Quantitative detection reliability test

[0130] (1) Preparation of standard curve

[0131] The inventors have experimentally confirmed that the ultraviolet absorbance of the six PAHs benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene and fluoranthene shows a good linear relationship with the concentration in the range of 5-50 mg / L (i.e., 5000-50000 ppb), and the fluorescence intensity shows a good linear relationship with the concentration in the concentration ranges of 0.1-50 ppb, 0.1-50 ppb, 0.1-50 ppb, 0.2-50 ppb, 0.5-50 ppb and 0.3-50 ppb, respectively. The following is the process of making a standard curve within the above range.

[0132] The standard curves of the following six PAHs, benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene, and fluoranthene, were prepared according to the following methods:

[0133] Prepare acetonitrile or methanol solutions with different concentrations of PAHs within the above range as standard solutions. The concentration of the standard solution for UV-visible spectroscopy detection is as follows:

[0134] The concentrations of the standard solutions of benzo[a]pyrene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L, respectively; the concentrations of the standard solutions of naphthalene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L, respectively; the concentrations of the standard solutions of phenanthrene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L, respectively. The concentrations of the standard solution of fluorene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L and 50 mg / L respectively; the concentrations of the standard solution of anthracene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L and 50 mg / L respectively; the concentrations of the standard solution of fluoranthene are 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L and 50 mg / L respectively.

[0135] The concentration of the standard solution for fluorescence spectrum detection is as follows:

[0136] The concentrations of the standard solutions of benzo[a]pyrene are 0.1ppb, 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb, and 50ppb, respectively; the concentrations of the standard solutions of naphthalene are 0.1ppb, 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb, and 50ppb, respectively; the concentrations of the standard solutions of phenanthrene are 0.1ppb, 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb, and 50ppb, respectively. The concentrations of the standard solution of fluorene are 0.2ppb, 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb and 50ppb respectively; the concentrations of the standard solution of anthracene are 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb and 50ppb respectively; the concentrations of the standard solution of fluoranthene are 0.3ppb, 0.5ppb, 1ppb, 5ppb, 10ppb, 20ppb, 30ppb, 40ppb and 50ppb respectively.

[0137] The above standard solutions were filtered at a rate of 2 mL / min using the cyclodextrin-modified nylon membrane material prepared in Example 1, and then the absorbance and fluorescence intensity of the filtration surface of the cyclodextrin-modified membrane material were tested using an ultraviolet-visible spectrometer (scanning wavelength range 200-400 nm, wavelength resolution 1 nm) and a fluorescence spectrometer (excitation wavelength 300 nm, scanning range 300-500 nm). A standard curve was prepared based on the concentration of the standard solution and the absorbance / fluorescence intensity at the characteristic peak. The formula and correlation coefficient (R 2 ) are shown in Table 5 below.

[0138] Table 5 List of standard curves of PAHs

[0139]

[0140] In the ultraviolet-visible absorption spectrum, benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene, and fluoranthene show characteristic absorption peaks at 252nm, 275nm, 290nm, 303nm, 340nm, and 320nm, respectively. In the fluorescence spectrum, benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene, and fluoranthene show characteristic absorption peaks at 405nm, 335nm, 355nm, 315nm, 390nm, and 433nm, respectively.

[0141] From the results in the above table, it can be seen that PAHs show a good linear correlation with the absorbance detected by UV-visible spectroscopy and the fluorescence intensity detected by fluorescence spectroscopy (e.g. Figure 2 and 3The fluorescence spectrum of benzo[a]pyrene and the corresponding standard curve are schematically shown, and the correlation coefficients are all above 99.6%, which can be used as a standard curve to test the concentration of PAHs in water.

[0142] (2) Accuracy test

[0143] A. Single substance testing

[0144] Acetonitrile solutions of benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene and fluoranthene with different concentrations were prepared as simulated wastewater, and the cyclodextrin-modified nylon membrane material prepared in Example 1 was used to filter the simulated wastewater using the method for preparing the standard curve, and fluorescence spectrum detection was performed.

[0145] Combined with the fluorescence intensity obtained by detection, the concentration of the simulated wastewater was determined using the aforementioned standard curve, and the results are shown in Table 6 below.

[0146] Table 6 Fluorescence spectrum detection results of individual PAHs

[0147] substance Preparation concentration (ppb) Detection concentration (ppb) error(%) Benzo[a]pyrene 10 10.2 +2％ Naphthalene 5 5.1 +2％ Philippines 10 9.8 -2％ Fluorine 20 19.9 -0.5％ Anthracene 50 49.8 -0.4％ Fluoranthene 30 30.1 +0.3％

[0148] From the results in the above table, it can be seen that the error of the detection result of the method of the present invention for a single PAHs is less than 2%, and the detection limit of the fluorescence spectrum detection can reach 0.1 ppb, indicating that the cyclodextrin modified nylon membrane material provided by the present invention can be used for the concentration detection of a single PAHs substance with high accuracy and sensitivity.

[0149] B. PAHs mixture detection

[0150] An acetonitrile solution containing benzo[a]pyrene, naphthalene, phenanthrene, fluorene, anthracene and fluoranthene was prepared as simulated wastewater, and the cyclodextrin-modified nylon membrane material prepared in Example 1 was used to filter the simulated wastewater using the method for preparing the standard curve, and fluorescence spectrum detection was performed.

[0151] Combined with the fluorescence intensity obtained by detection, the concentration of the simulated wastewater was determined using the aforementioned standard curve. The results are shown in Table 7 below.

[0152] Table 7 Fluorescence spectrum detection results of PAHs mixture solutions

[0153] substance Preparation concentration (ppb) Detection concentration (ppb) error(%) Benzo[a]pyrene 10 10.1 +1％ Naphthalene 10 9.9 -1％ Philippines 10 10.2 +2％ Fluorine 10 9.8 -2％ Anthracene 10 10.0 0％ Fluoranthene 10 10.1 +1％

[0154] From the results in the above table, it can be seen that the error of the detection result of the PAHs mixture by the method of the present invention is less than 2%, indicating that the cyclodextrin modified nylon membrane material provided by the present invention can be used for the concentration detection of the PAHs mixture and can accurately detect the concentration of each substance.

[0155] C. Matrix Interference Test

[0156] Take river water, lake water and industrial wastewater respectively, and determine by liquid chromatography method to determine that there are no PAHs therein. Then take river water, lake water and industrial wastewater as solvents respectively, add known concentrations of benzo[a]pyrene, naphthalene and phenanthrene as simulated wastewater, wherein benzo[a]pyrene 5ppb in river water, naphthalene 10ppb in lake water, and phenanthrene 20ppb in industrial wastewater. Use the cyclodextrin modified nylon membrane material prepared in Example 1, filter the simulated wastewater using the method in the standard curve preparation, and perform fluorescence spectrum detection, and the test results are shown in Table 8 below. Wherein matrix interference is the error obtained by comparing the result detected by the method of the present invention with the result detected by liquid chromatography.

[0157] Table 8 Matrix interference test results

[0158] Water Sample Preparation concentration (ppb) Detection concentration (ppb) error(%) Matrix interference (%) River Water 5 5.1 +2％ 5％ Lake water 10 9.8 -2％ 3％ Industrial wastewater 20 19.6 -2％ 8％

[0159] It can be seen from the results in the above table that the complex matrix in the water body has little effect on the detection results, the matrix interference does not exceed 8%, and the detection error is no more than 2%, which is an acceptable error, indicating that the solid phase extraction spectroscopy technology based on the cyclodextrin modified nylon membrane material of the present invention can be used for the detection of actual water bodies.

[0160] Application Example 1

[0161] Water samples from urban rivers were taken and filtered through a 0.45 μm filter membrane to remove suspended particles to obtain pretreated water samples.

[0162] 200 mL of the pretreated water sample was passed through the cyclodextrin-modified nylon membrane material obtained in Example 1 at a rate of 10 mL / min to obtain an enriched membrane material and a filtrate.

[0163] The filtrate was subjected to HPLC test, and the results showed that the filtrate did not contain polycyclic aromatic hydrocarbons, indicating that the polycyclic aromatic hydrocarbons in the filtrate were completely adsorbed by the cyclodextrin-modified nylon membrane material.

[0164] The filter surface of the enriched membrane material was subjected to UV-visible spectroscopy and fluorescence spectroscopy, where the measurement wavelength of UV-visible spectroscopy was 200-400nm, and the absorption peak in the range of 250-350nm was recorded; the excitation wavelength of fluorescence spectroscopy was 300nm, the scanning range was 300-500nm, and the emission peak in the range of 350-450nm was recorded. The results showed that the absorption peak position of UV-visible spectroscopy was 340nm, and the polycyclic aromatic hydrocarbons in the water body could be determined to be anthracene. According to the emission peak intensity of fluorescence spectroscopy and the standard curve, the concentration of the substance was 2.5ppb.

[0165] The enriched membrane material was eluted with acetonitrile to elute the adsorbed PAHs, and the obtained eluate was detected using a high performance liquid chromatography-fluorescence detector, and the measured concentration was 2.49 ppb. The result was basically the same as that using the method provided by the present invention, indicating that the method of the present invention can obtain accurate results when used for the detection of actual water bodies.

[0166] Application Comparative Example 1

[0167] The method of Application Example 1 was used to test the types and concentrations of PAHs in water samples of urban rivers, with the only difference being that the cyclodextrin-modified nylon membrane material was replaced with the raw nylon membrane used in Example 1.

[0168] After the wastewater was filtered using a nylon membrane, the intensities of the absorption peak and emission peak were weak when UV-visible spectroscopy and fluorescence spectroscopy were performed. Combined with the standard curve, the concentration was only 0.8 ppb.

[0169] Application Example 2

[0170] Industrial wastewater discharged from a chemical plant was taken as a water sample, and filtered through a 0.45μm filter membrane to remove suspended particles to obtain a pretreated water sample.

[0171] 450 mL of the pretreated water sample was passed through the cyclodextrin-modified nylon membrane material obtained in Example 2 at a rate of 15 mL / min to obtain an enriched membrane material.

[0172] The filtrate was subjected to HPLC test, and the results showed that the filtrate did not contain polycyclic aromatic hydrocarbons, indicating that the polycyclic aromatic hydrocarbons in the filtrate were completely adsorbed by the cyclodextrin-modified nylon membrane material.

[0173] The filter surface of the enriched membrane material was subjected to UV-visible spectroscopy and fluorescence spectroscopy, wherein the measurement wavelength of the UV-visible spectroscopy was 200-400nm, and the absorption peak in the range of 250-350nm was recorded; the excitation wavelength of the fluorescence spectroscopy was 280nm, the scanning range was 300-500nm, and the emission peak in the range of 350-450nm was recorded.

[0174] A significant absorption peak appeared at 340nm in the UV spectrum, indicating the presence of anthracene in the sample. The emission intensity of the fluorescence spectrum was high, and combined with the above standard curve, the concentration of the substance was 8ppb.

[0175] The enriched membrane material was eluted with acetonitrile to elute the adsorbed PAHs, and the obtained eluate was detected using a high performance liquid chromatography-fluorescence detector, and the measured concentration was 7.8 ppb. The result was basically the same as that using the method provided by the present invention, indicating that the method of the present invention can obtain accurate results when used for the detection of actual water bodies.

[0176] Application Comparative Example 2

[0177] Using ethyl acetate as the extractant, 1000 mL of the same wastewater as in Application Example 2 was extracted by liquid-liquid extraction, extracted 3 times, each time with 5 mL, and the combined extracts were used as the test liquid, then the test liquid was purged with nitrogen and concentrated to 3 mL, and detected by high performance liquid chromatography-fluorescence detection (HPLC-FL), and the wastewater was found to contain anthracene with a concentration of 6.5 ppb. This method takes about 60 minutes, of which HPLC-FL detection takes 30 minutes.

[0178] From the above results, it can be seen that the concentration obtained by the traditional liquid-liquid extraction method is much lower than the calibration concentration and the result of the test method provided by the present invention.

[0179] Application Example 3

[0180] Take water from a certain lake as a water sample, filter it through a 0.45μm filter membrane to remove suspended particles, and obtain a pretreated water sample.

[0181] 75 mL of the pretreated water sample was passed through the cyclodextrin-modified nylon membrane material obtained in Example 1 at a rate of 15 mL / min to obtain an enriched membrane material.

[0182] The filtrate was subjected to HPLC test, and the results showed that the filtrate did not contain polycyclic aromatic hydrocarbons, indicating that the polycyclic aromatic hydrocarbons in the filtrate were completely adsorbed by the cyclodextrin-modified nylon membrane material.

[0183] The filter surface of the enriched membrane material was subjected to UV-visible spectroscopy and fluorescence spectroscopy, wherein the measurement wavelength of the UV-visible spectroscopy was 200-400nm, and the absorption peak in the range of 250-350nm was recorded; the excitation wavelength of the fluorescence spectroscopy was 280nm, the scanning range was 300-500nm, and the emission peak in the range of 350-450nm was recorded. The absorption peak position of the UV-visible spectroscopy was 252nm, and it can be determined that the polycyclic aromatic hydrocarbons in the water body are benzo[a]pyrene. According to the emission peak intensity of the fluorescence spectroscopy and the standard curve, the concentration of benzo[a]pyrene can be obtained to be 1ppb.

[0184] The enriched membrane material was eluted with acetonitrile to elute the adsorbed benzopyrene. The resulting eluate was detected using a high performance liquid chromatography-fluorescence detector, and the measured concentration was 0.9 ppb. The result was basically the same as that using the method provided by the present invention, indicating that the method of the present invention can obtain more accurate results when used for the detection of actual water bodies.

[0185] Application Example 4

[0186] Groundwater from a polluted area was taken as a water sample and filtered through a 0.45 μm filter membrane to remove suspended particles to obtain a pretreated water sample.

[0187] 250 mL of the pretreated water sample was passed through the cyclodextrin-modified nylon membrane material obtained in Example 1 at a rate of 10 mL / min to obtain an enriched membrane material.

[0188] The filtrate was subjected to HPLC test, and the results showed that the filtrate did not contain polycyclic aromatic hydrocarbons, indicating that the polycyclic aromatic hydrocarbons in the filtrate were completely adsorbed by the cyclodextrin-modified nylon membrane material.

[0189] The filter surface of the enriched membrane material was subjected to UV-visible spectroscopy and fluorescence spectroscopy, wherein the UV-visible spectroscopy was measured at 200-400nm, and the absorption peak in the range of 250-350nm was recorded; the excitation wavelength of the fluorescence spectroscopy was 300nm, the scanning range was 300-500nm, and the emission peak in the range of 350-450nm was recorded. The absorption peak position of the UV-visible spectroscopy was 320nm, and it can be determined that the polycyclic aromatic hydrocarbons in the water body are fluoranthene. In the fluorescence spectroscopy test results, a strong emission characteristic peak appeared at 433nm. Combined with the emission characteristic peak positions of each substance determined previously, it can be determined that the groundwater contains fluoranthene. Combined with the aforementioned standard curve, the concentration of fluoranthene can be obtained to be 5ppb.

[0190] The enriched membrane material was eluted with acetonitrile to elute the adsorbed fluoranthene, and the obtained eluate was detected using a high performance liquid chromatography-fluorescence detector, and the measured concentration was 5.3 ppb. The result was basically the same as that using the method provided by the present invention, indicating that the method of the present invention can obtain accurate results when used for the detection of actual water bodies.

[0191] While preferred embodiments of the present invention have been shown and described, it is contemplated that those skilled in the art may devise various modifications of the present invention within the spirit and scope of the appended claims.

Claims

1. A cyclodextrin-modified nylon membrane material, comprising a nylon membrane and β-cyclodextrin grafted onto the nylon membrane.

2. The cyclodextrin modified nylon membrane material according to claim 1, characterized in that: The grafting amount of β-cyclodextrin is 1.0-1.4 mg / cm 2 .

3. The cyclodextrin modified nylon membrane material according to claim 1 or 2, characterized in that: The thickness of the nylon membrane is 50-150 μm, and the pore size is 0.1-0.45 μm.

4. A method for preparing the cyclodextrin-modified nylon membrane material according to any one of claims 1 to 3, comprising the following steps: The nylon membrane is immersed in a beta-cyclodextrin solution to carry out a grafting modification reaction to obtain a cyclodextrin-modified nylon membrane material.

5. The preparation method according to claim 4, characterized in that: The concentration of the β-cyclodextrin solution is 1-10 g / L, and the pH of the β-cyclodextrin solution is 4.5-6.

0.

6. The preparation method according to claim 4 or 5, characterized in that: The temperature of the grafting modification reaction is 25-60° C., and the reaction time is 2-6 hours.

7. The preparation method according to claim 4, characterized in that: The preparation method further comprises activating the nylon membrane before immersing the nylon membrane in the β-cyclodextrin solution. Wherein, the activation treatment includes at least one of oxidant treatment and plasma treatment.

8. Use of the cyclodextrin-modified nylon membrane material according to any one of claims 1 to 3 or the cyclodextrin-modified nylon membrane material obtained by the preparation method according to any one of claims 4 to 7 in the removal or detection of polycyclic aromatic hydrocarbons.

9. A method for detecting polycyclic aromatic hydrocarbons in water, comprising the following steps: Using the cyclodextrin-modified nylon membrane material according to any one of claims 1 to 3 or the cyclodextrin-modified nylon membrane material obtained by the preparation method according to any one of claims 4 to 7 to filter the water body to be tested containing polycyclic aromatic hydrocarbons to obtain the membrane material to be tested, The filter surface of the membrane material to be tested is subjected to spectral detection to obtain the characteristic peak intensity. The content of the polycyclic aromatic hydrocarbons is obtained according to the characteristic peak intensity and the standard curve of the polycyclic aromatic hydrocarbons.

10. The detection method according to claim 9, characterized in that: The flow rate of the filtration is 0.01-1.20 mL / (min·cm 2 ); the spectral detection is ultraviolet-visible spectral detection or fluorescence spectral detection, the wavelength range of the ultraviolet-visible spectral detection is 200-400nm, the excitation light wavelength of the fluorescence spectral detection is 280-395nm, and the spectral scanning range is 300-500nm.

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