Preparation method for polyethyleneimine functionalized phenolic aerogel-coated extraction fibers

Abstract

A method for preparing polyethyleneimine functionalized phenolic aerogel-coated extraction fibers on basalt fibers, in particular relating to using polyethyleneimine to perform chemical functionalization during preparation of a phenolic aerogel coating, and bonding to basalt fibers. The novel method is characterized in that basalt fibers are selected as a carrier, amination modification is first performed on the surfaces thereof, a phenolic aerogel coating is then prepared in situ, polyethyleneimine is added into a coating preparation reaction to perform chemical functionalization, and a polyethyleneimine functionalized phenolic aerogel coating is produced on the surfaces of the basalt fibers. The extraction fibers prepared by the method possess advantages such as having good coating stability and excellent extraction performance, and being suitable for solid phase microextraction tube filling. The extraction fibers can be used for enriching and analyzing trace estrogen in environmental, medicinal and biochemical samples etc., and have good application potential.

Description

Preparation method of polyethyleneimine functionalized phenolic aerogel coating extraction fiber Technical Field

[0001] The invention relates to a technology for preparing extraction fibers with polyethyleneimine functionalized phenolic aerogel coating on basalt fibers. Background Art

[0002] In-tube solid-phase microextraction (SPME) is a new sample pretreatment technology developed in recent years that integrates sampling, enrichment, purification, and analysis. It can be used online with liquid chromatography and has great applications in environmental analysis, biochemical testing, and other fields. Compared with conventional empty-tube SPME, fiber-filled SPME can effectively improve extraction efficiency and greatly improve analytical sensitivity. The extraction fiber in the tube determines the efficiency of fiber-filled SPME. Basalt fiber is drawn from molten basalt. Its main component is silicon dioxide. Its surface is rich in silanols and is easy to chemically modify. It is a new type of fiber material that is cheap, readily available, and green. Its surface can be chemically modified and then used in in-tube solid-phase microextraction.

[0003] Aerogel is a three-dimensional porous solid material with extremely high porosity, very low density, high specific surface area, and ultra-high pore volume ratio. Aerogels are typically prepared through a sol-gel process and drying. During the sol-gel process, by controlling the hydrolysis and polycondensation reaction conditions of the solution, nanoclusters of different structures are formed within the sol. These clusters adhere to each other to form a gel. Aerogels are then obtained through aging, drying, and solvent replacement. Aerogels are categorized into inorganic and organic aerogels based on their chemical composition. Phenolic aerogel is an organic aerogel prepared using resorcinol and formaldehyde as raw materials. Aerogels are excellent adsorbents, exhibiting good adsorption for a variety of substances and are potential coating materials for solid-phase microextraction.

[0004] Polyethyleneimine is a water-soluble polymer with the highest known charge density of cationic organic polymers. Its molecular structure contains primary, secondary, and tertiary amine groups, which are highly chemically reactive. For example, amine groups can react with carboxyl groups to form hydrogen bonds or ionic bonds. These excellent properties have broad applications in wastewater treatment, adhesives, coatings, and fiber processing. It can be used to chemically functionalize aerogels, yielding functionalized aerogel materials that combine the properties of both, and can be used to prepare high-performance extraction fiber coatings. Summary of the Invention

[0005] The present invention aims to provide a fiber extraction technology for preparing a polyethyleneimine-functionalized phenolic aerogel coating on basalt fiber. This technology utilizes polyethyleneimine in the aerogel preparation reaction during the phenolic aerogel formation process on the basalt fiber surface to obtain a functionalized aerogel coating. The method comprises the following steps:

[0006] (1) Preparation of amino-treated basalt fiber

[0007] After washing and drying the basalt fiber, the fiber is placed in a toluene solution containing 10-30% by weight of aminopropyltrimethoxysilane, the temperature is raised to 80-120° C., and the mixture is stirred and refluxed for 12-24 hours to obtain the amino-modified basalt fiber.

[0008] (2) Preparation of polyethyleneimine functionalized phenolic aerogel-coated extraction fibers

[0009] In a reactor, a resorcinol aqueous solution, a formaldehyde aqueous solution and a polyethyleneimine aqueous solution are added in sequence and mixed evenly to obtain a mixed solution, wherein the mass ratio of the resorcinol, formaldehyde and polyethyleneimine in the mixed solution is 1:0.5-1:0.5-1, the amino-treated basalt fiber is immersed in the mixed solution, and then sodium carbonate is added and its mass percentage is controlled to be 1-4%. The temperature is controlled between 20-40°C, and the fiber is allowed to stand for 4-8 hours to form a sol. The temperature is raised to 70-100°C for aging, and the aging time is 48-72 hours. The fiber is washed with water and then solvent replaced with ethanol. Finally, the fiber is freeze-dried to obtain the polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber.

[0010] In the step (2) of the present invention, the mass percentage of resorcinol in the mixed solution is 10-20%.

[0011] In the step (2) of the present invention, the solid-liquid ratio of the amino basalt fiber to the mixed solution is 1 g: 80-100 mL.

[0012] In the present invention, the solvent is replaced 3-6 times in step (2), each time for 2-4 hours.

[0013] Another object of the present invention is to provide a polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber, which is loaded into a polyetheretherketone (PEEK) tube to prepare a solid-phase microextraction tube, which is coupled online with a liquid chromatography and applied to the analysis and detection of estrogen pollutants in environmental water samples.

[0014] The polyethyleneimine functionalized phenolic aerogel coating extraction fiber prepared by the present invention has the following advantages:

[0015] (1) Basalt fiber as a carrier can effectively improve the chemical bonding between the aerogel coating and the carrier, thereby increasing the stability of the extraction coating.

[0016] (2) The polyethyleneimine functionalized phenolic aerogel coating extraction fiber filled extraction tube was combined with chromatography to develop an online analysis method, reduce the system error, and adapt to the development trend of analytical chemistry.

[0017] (3) The use of polyethyleneimine functionalized phenolic aerogel coated extraction fiber filled extraction tube in conjunction with chromatography greatly improved the analysis speed, shortened the sample analysis time to 20 min, and increased the sensitivity of existing chromatographic instruments by three orders of magnitude. DETAILED DESCRIPTION

[0018] In order to better understand the present invention, the following examples are provided:

[0019] Example 1:

[0020] (1) Preparation of amino-treated basalt fiber

[0021] After washing and drying the basalt fiber, the fiber was placed in a toluene solution containing 10% by weight of aminopropyltrimethoxysilane, the temperature was raised to 110°C, and the mixture was stirred and refluxed for 24 hours to obtain amino-treated basalt fiber.

[0022] (2) Preparation of polyethyleneimine functionalized phenolic aerogel-coated extraction fibers

[0023] In the reactor, resorcinol aqueous solution, formaldehyde aqueous solution and polyethyleneimine aqueous solution were added in sequence and mixed evenly to obtain a mixed solution. The mass ratio of resorcinol, formaldehyde and polyethyleneimine in the mixed solution was 1:1:1, and the mass percentage of resorcinol in the mixed solution was 10%. Aminated basalt fiber was immersed in the mixed solution, and the solid-liquid ratio of amino basalt fiber to the mixed solution was 1 g:80 mL. Sodium carbonate was added and its mass percentage was controlled to 1%. The temperature was controlled at 40°C and the fiber was allowed to stand for 4 hours to form a sol. The temperature was raised to 100°C for aging for 48 hours. After washing with water, the fiber was solvent-displaced with ethanol for 5 times, each time for 2 hours. Finally, the fiber was freeze-dried to obtain polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber.

[0024] Example 2:

[0025] (1) Preparation of amino-treated basalt fiber

[0026] After washing and drying the basalt fiber, the fiber was placed in a toluene solution containing 20% ​​by weight of aminopropyltrimethoxysilane, the temperature was raised to 100°C, and the solution was stirred and refluxed for 18 hours to obtain amino-modified basalt fiber.

[0027] (2) Preparation of polyethyleneimine functionalized phenolic aerogel-coated extraction fibers

[0028] In the reactor, resorcinol aqueous solution, formaldehyde aqueous solution and polyethyleneimine aqueous solution were added in sequence and mixed evenly to obtain a mixed solution. The mass ratio of resorcinol, formaldehyde and polyethyleneimine in the mixed solution was 1:0.5:0.5, and the mass percentage of resorcinol in the mixed solution was 20%. Aminated basalt fiber was immersed in the mixed solution. The solid-liquid ratio of amino basalt fiber to the mixed solution was 1 g:90 mL. Sodium carbonate was added and its mass percentage was controlled to 4%. The temperature was controlled at 20°C and the solution was allowed to stand for 8 hours to form a sol. The temperature was raised to 70°C for aging. The aging time was 72 hours. After washing with water, the solvent was replaced with ethanol three times for 4 hours each time. Finally, it was freeze-dried to obtain polyethyleneimine functionalized phenolic aerogel coating extraction fiber.

[0029] Example 3:

[0030] (1) Preparation of amino-treated basalt fiber

[0031] After washing and drying the basalt fiber, the fiber was placed in a toluene solution containing 30% by weight of aminopropyltrimethoxysilane, the temperature was raised to 80°C, and the mixture was stirred and refluxed for 24 hours to obtain amino-modified basalt fiber.

[0032] (2) Preparation of polyethyleneimine functionalized phenolic aerogel-coated extraction fibers

[0033] In the reactor, resorcinol aqueous solution, formaldehyde aqueous solution and polyethyleneimine aqueous solution were added in sequence and mixed evenly to obtain a mixed solution. The mass ratio of resorcinol, formaldehyde and polyethyleneimine in the mixed solution was 1:0.75:0.75, and the mass percentage of resorcinol in the mixed solution was 15%. Aminated basalt fiber was immersed in the mixed solution. The solid-liquid ratio of amino basalt fiber to the mixed solution was 1 g:100 mL. Sodium carbonate was added and its mass percentage was controlled to 2.5%. The temperature was controlled at 30°C and the fiber was allowed to stand for 6 hours to form a sol. The temperature was raised to 90°C for aging for 60 hours. After washing with water, the solvent was replaced with ethanol 4 times for 3 hours each time. Finally, the fiber was freeze-dried to obtain polyethyleneimine functionalized phenolic aerogel coating extraction fiber.

[0034] Example 4:

[0035] A 40-cm-long bundle of 150 mg polyethyleneimine-functionalized phenolic aerogel-coated extraction fibers was packed into a 40-cm-long PEEK tube with an inner diameter of 0.75 mm to create a solid-phase microextraction (SPME) tube. This SPME-filled tube, instead of a sample loop, was connected to a six-port liquid chromatography injection valve and an external sample delivery pump. Extraction was performed at a sample flow rate of 2 mL / min for 15 minutes, followed by a 1-minute rotary elution. This enabled the online extraction and analysis of four estrogens—estrone, diethylstilbestrol, hexestrol, and 17α-ethinylestradiol—in environmental water samples within 20 minutes. The linear range reached 0.05-20 μg / L, the detection limit was as low as 0.01 μg / L, and the enrichment factor was over 1000-fold, improving the sensitivity of existing direct injection instruments by three orders of magnitude.

Claims

1. A preparation method of a polyethyleneimine-functionalized phenolic aerogel coating extraction fiber, characterized in that, The method has the following process steps: (1) Preparation of amino-functionalized basalt fibers After cleaning and drying the basalt fibers, they are placed in a toluene solution of 3-aminopropyltrimethoxysilane with a mass percentage content of 10-30%. The temperature is raised to between 80-120°C, and the reaction is carried out under constant temperature, stirring, and reflux for 12-24 hours to obtain amino-functionalized basalt fibers; (2) Preparation of polyethyleneimine-functionalized phenolic aerogel-coated extraction fibers In a reactor, aqueous resorcinol solution, aqueous formaldehyde solution, and aqueous polyethyleneimine solution are added in sequence, and after mixing evenly, a mixed solution is obtained. The mass ratio of resorcinol, formaldehyde, and polyethyleneimine in the mixed solution is 1:0.5-1:0.5-1. The amino-functionalized basalt fibers are immersed in the mixed solution, and then sodium carbonate is added and its mass percentage content is controlled to be 1-4%. The temperature is controlled between 20-40°C, and it is left standing for 4-8 hours to form a sol. The temperature is raised to between 70-100°C for aging, and the aging time is 48-72 hours. After washing with water, solvent replacement is carried out with ethanol, and finally freeze-drying is carried out to obtain polyethyleneimine-functionalized phenolic aerogel-coated extraction fibers.

2. The preparation method of a polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber according to claim 1, characterized in that In step (2), the mass percentage content of resorcinol in the mixed solution is 10-20%.

3. The preparation method of a polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber according to claim 1, characterized in that, In step (2), the solid-liquid ratio of the amino-functionalized basalt fibers to the mixed solution is 1 g:80-100 mL.

4. The preparation method of a polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber according to claim 1, characterized in that, In step (2), the solvent replacement is carried out 3-6 times, each time for 2-4 hours.

5. Polyethyleneimine-functionalized phenolic aerogel-coated extraction fibers prepared by the preparation method of a polyethyleneimine-functionalized phenolic aerogel-coated extraction fiber according to claim 1.