Intercalation coal gangue based surface molecular imprinting adsorption material and preparation method thereof

Abstract

The invention discloses an intercalated coal gangue based surface molecularly imprinted adsorption material and a preparation method thereof. The preparation method comprises the following steps: firstly, by taking intercalated coal gangue as a carrier, phenol as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linking agent and azodiisobutyronitrile as an initiator, preparing an intercalated coal gangue based surface molecularly imprinted adsorption material; and carrying out surface molecular imprinting reaction on the surface of the intercalated coal gangue to form a polymer layer. And the template molecules and the functional monomer assembly are fixed together by the layer. And eluting to remove phenol template molecules to finally obtain the intercalated coal gangue-based surface molecularly imprinted adsorption material with a specific adsorption aperture structure. The coal gangue is used as a raw material, treated and then mixed with an intercalator solution with a certain concentration to prepare the coal gangue intercalator. The intercalation process comprises direct intercalation of dimethyl sulfoxide, two-time intercalation of dimethyl sulfoxide and methanol and macromolecule intercalation of cetyltrimethylammonium bromide, the intercalation process and the imprinting effect are optimized, and the phenol adsorption performance and specific adsorption of phenol are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment adsorption materials, and relates to an intercalated gangue-based surface molecular imprinting adsorption material and a preparation method thereof. Background Art

[0002] Coal chemical wastewater has the characteristics of large water volume, complex composition and a large amount of organic matter. Among them, phenol, as a common organic substance, is highly toxic and irritating. Long-term exposure to wastewater containing phenol may cause damage to the nervous system, liver and respiratory system of organisms. China has listed phenol as one of the priority pollutants to be controlled, requiring the concentration of phenols in the treated water to be less than 1 mg / L. Therefore, the selective treatment and recovery of phenol in coal chemical wastewater is particularly important.

[0003] In the precise recovery of phenol-containing wastewater, molecular imprinting technology is widely used due to its highly selective adsorption capacity and good stability. Juncheng Zhang et al. used porous carbon gel as a carrier to prepare a three-dimensional monolithic surface molecular imprinting polymer adsorbent, and successfully applied it to alkaline wastewater with complex components, showing an adsorption capacity of 58.4 mg / g for phenol. On the other hand, Feifei Duan et al. used porous graphene oxide as a carrier to prepare a surface molecular imprinting polymer adsorbent, and successfully applied it to real river water, with an adsorption capacity of up to 60.6 mg / g for bisphenol A. In addition, patent CN 117599759 A describes a three-dimensional macroscopic block-shaped high adsorption activity imprinted adsorbent material formed by hydrothermal imprinting reaction using chitosan carbon aerogel as a matrix, which can adsorb 42.5 mg / g of phenol. These studies fully demonstrate the potential and application prospects of molecular imprinting materials in the treatment of phenol pollutants. As the main solid waste generated in the process of coal mineralization, coal gangue has an annual emission of about 15% to 25% of the total coal mining, becoming one of the largest solid wastes in the world. However, coal gangue has a rich pore structure and specific surface area, which is conducive to the formation of more imprinted pores, thereby improving the selectivity for target molecules. Therefore, how to achieve the effective utilization of coal gangue, especially using it as a carrier to prepare selective adsorption materials, has good research and development value and application potential. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art and to provide an intercalated coal gangue-based surface molecular imprinting adsorption material and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing an intercalated coal gangue-based surface molecular imprinting adsorption material, comprising: Using coal gangue as raw material, intercalation reaction occurs in a solution containing an intercalation agent, and intercalated coal gangue is formed through centrifugal separation and drying; Using intercalated coal gangue as a carrier, phenol and methacrylic acid are added to acetonitrile solvent under an inert atmosphere for a preliminary reaction, and then a cross-linking agent and an initiator are added for a surface imprinting reaction to obtain an imprinting reaction product; The imprinting reaction product is treated to obtain intercalated coal gangue-based surface molecular imprinting adsorption material.

[0006] Preferably, the intercalation reaction includes a direct intercalation reaction of dimethyl sulfoxide, a double intercalation reaction of methanol, and a macromolecular intercalation reaction of hexadecyltrimethylammonium bromide.

[0007] Preferably, the intercalated coal gangue is mixed with a dimethyl sulfoxide intercalation agent solution, magnetically stirred under heating conditions, and then centrifuged and dried to obtain the directly intercalated coal gangue; Directly intercalated coal gangue and methanol solution are subjected to magnetic stirring under heating conditions, centrifuged, and the upper layer solution is poured off to obtain methanol twice intercalated coal gangue; The coal gangue intercalated with methanol twice is mixed with the methanol solution of hexadecyltrimethylammonium bromide, the two are stirred evenly, and the product is repeatedly washed with an ethanol solution, and the hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue is obtained after suction filtration.

[0008] Preferably, the gangue and the methyl sulfoxide solution are stirred at 60°C to 70°C for 20h to 24h, with a stirring speed of 300r / min to 500r / min; the centrifugal speed is 4000r / min to 5000r / min, the centrifugal time is 3min to 5min, and finally dried at 60°C to 70°C for 20h to 24h to obtain directly intercalated gangue; wherein the addition ratio of the gangue to the methyl sulfoxide solution is 8g to 10g: 100ml to 200ml; Take directly intercalated coal gangue and methanol, stir them magnetically at 50℃~60℃ for 20h~24h, then centrifuge them at a centrifugal speed of 4000 r / min~5000r / min, and a centrifugal time of 3min~5min, and finally dry them at 60℃~70℃ for 20h~24h to obtain methanol twice intercalated coal gangue; wherein the dosage ratio of directly intercalated coal gangue to methanol is 3g~5g:80ml~100ml; The coal gangue intercalated with methanol twice is mixed with a methanol solution of hexadecyltrimethylammonium bromide, and magnetically stirred at 50°C to 60°C for 20h to 24h, and then centrifuged at a centrifugal speed of 4000 r / min to 5000r / min for 3min to 5min, and finally dried at 60°C to 70°C for 20h to 24h to obtain the coal gangue intercalated with hexadecyltrimethylammonium bromide macromolecules; Wherein, the usage ratio of methanol twice intercalated coal gangue and methanol solution of hexadecyltrimethylammonium bromide is 3g~5g:80~100ml.

[0009] Preferably, the gangue needs to be ground to 200-350 mesh and calcined at 700-800°C; the mass ratio of dimethyl sulfoxide solution to water is 9:1-9:2; and the concentration of the methanol solution of hexadecyltrimethylammonium bromide is 20 mg / L-30 mg / L.

[0010] Preferably, in the preliminary reaction process: the mass ratio of intercalated coal gangue, phenol and methacrylic acid is (1-3): (0.5-1): (2-9); the reaction temperature is controlled at 20°C to 30°C, and the reaction time is 1h to 2h.

[0011] Preferably, during the surface imprinting reaction: the crosslinking agent is ethylene glycol dimethacrylate, the initiator is azobisisobutyronitrile; the mass ratio of ethylene glycol dimethacrylate to azobisisobutyronitrile is (0.5~1.5):(0.1~0.45); the reaction temperature is controlled at 60°C~70°C, and the reaction time is 22h~24h.

[0012] Preferably, the imprinting reaction product is processed to obtain the intercalated gangue-based surface molecular imprinting adsorption material, specifically: The imprinted reaction product is washed with a mixture of methanol and acetic acid as an eluent to remove the phenol template molecules on the imprinted reaction product; the washed imprinted reaction product is dried to obtain an intercalated coal gangue-based surface molecular imprinting adsorption material.

[0013] Preferably, the volume ratio of methanol to acetic acid is 9:1 to 9:2, and the washed imprinting reaction product is dried for 12 h to 14 h.

[0014] The invention discloses an intercalated coal gangue-based surface molecular imprinting adsorption material, which is prepared by adopting a preparation method of the intercalated coal gangue-based surface molecular imprinting adsorption material.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention aims to provide a preparation method of an intercalated coal gangue-based surface molecular imprinting adsorption material, which utilizes the rich pore structure on the surface of coal gangue and forms a structure with a specific adsorption pore size through a surface modification method. This structure can significantly improve the adsorption capacity and specificity of the intercalated coal gangue material for phenol, so that it can achieve efficient and specific adsorption of phenol in complex coal chemical wastewater. The method first uses intercalated coal gangue as a carrier, uses phenol as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinking agent, and azobisisobutyronitrile as an initiator to perform a surface molecular imprinting reaction on the surface of the intercalated coal gangue to form a polymer layer. This layer fixes the template molecule and the functional monomer assembly together. Subsequently, the phenol template molecule is eluted to remove, and finally an intercalated coal gangue-based surface molecular imprinting adsorption material with a structure with a specific adsorption pore size is obtained. The intercalated coal gangue is prepared by mixing coal gangue as a raw material, grinding and calcining, and then mixing with an intercalation agent solution of a certain concentration. The intercalation process includes direct intercalation of dimethyl sulfoxide using dimethyl sulfoxide, two intercalations of methanol, and macromolecular intercalation of hexadecyltrimethylammonium bromide. The intercalated gangue-based surface molecular imprinting adsorption material of the present invention assembles and fixes phenol template molecules and functional monomers in a cross-linked polymer layer through a surface imprinting reaction. After eluting and removing the phenol template molecules with a mixed solution of methanol and acetic acid, a large number of pore structures that specifically recognize phenol molecules are formed on the surface of the material. This structure enables the intercalated gangue-based surface molecular imprinting adsorption material to efficiently and selectively adsorb phenol molecules. The present invention utilizes the rich pore size and active sites of intercalated gangue, and introduces active groups by covalently bonding or physically adsorbing methacrylic acid as a functional monomer to the gangue surface. At the same time, ethylene glycol dimethacrylate is used as a cross-linking agent to form a stable network structure and enhance the mechanical strength and chemical stability of the modified layer. This surface modification process improves the surface properties of the intercalated coal gangue, making it an efficient intercalated coal gangue-based surface molecular imprinting adsorption material, achieving specific recognition and efficient adsorption capacity for phenol. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 These are the scanning electron microscopic analysis of the coal gangue of Example 1 (a), the scanning electron microscopic analysis of the coal gangue intercalated with hexadecyltrimethylammonium bromide macromolecules (b), and the scanning electron microscopic analysis of the intercalated coal gangue-based surface molecular imprinting adsorption material (c).

[0018] Figure 2 The figures are the Fourier transform infrared diffuse reflectance spectrometer analysis diagram of the intercalated gangue-based surface molecular imprinting adsorption material of Example 1 (a), the specific surface area analysis diagram of gangue and intercalated gangue-based surface molecular imprinting adsorption material (b), and the pore structure analysis diagram of gangue and intercalated gangue-based surface molecular imprinting adsorption material (c).

[0019] Figure 3 This is the selective adsorption performance of the intercalated coal gangue-based surface molecular imprinting adsorption material in Example 1.

[0020] Figure 4 This is a selective adsorption performance diagram of the intercalated gangue-based surface molecular imprinting adsorption material of Example 1, the acrylic acid intercalated gangue-based surface molecular imprinting adsorption material, and the methacrylamide intercalated gangue-based surface molecular imprinting adsorption material. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings: The present invention provides a method for preparing a suitable intercalated coal gangue-based surface molecularly imprinted adsorption material, the steps of which are as follows: 1) Using coal gangue as raw material, multiple intercalation reactions occur in an intercalation agent-containing solution, and intercalated coal gangue is formed through centrifugal separation and drying.

[0026] 2) The present invention uses intercalated coal gangue as a carrier, and adds phenol template molecules and methacrylic acid functional monomers to an acetonitrile solvent system under an inert atmosphere for a preliminary reaction. Subsequently, ethylene glycol dimethacrylate is added as a crosslinker and azobisisobutyronitrile is added as an initiator to perform a surface imprinting reaction. This process effectively fixes the template molecules and functional monomers on the pore structure of the intercalated coal gangue carrier, and finally obtains an imprinting reaction product.

[0027] 3) The phenol template molecules on the imprinted reaction product are eluted and removed to obtain a three-aperture intercalated coal gangue-based surface molecular imprinting adsorption material with rich specific recognition of phenol molecules.

[0028] The invention adopts multiple intercalation reactions of coal gangue, including direct intercalation of dimethyl sulfoxide using dimethyl sulfoxide, double intercalation of methanol, and macromolecular intercalation of hexadecyltrimethylammonium bromide.

[0029] Specifically, firstly, the direct intercalation gangue is obtained by mixing with a dimethyl sulfoxide intercalation agent solution of a certain concentration, magnetically stirring for several hours under heating conditions, and then centrifuging and drying; the direct intercalation gangue is mixed with a certain amount of methanol solution, magnetically stirred for several hours under heating conditions, centrifuged, and the upper solution is poured to obtain methanol twice intercalated gangue; the methanol twice intercalated gangue is mixed with a methanol solution of hexadecyltrimethylammonium bromide of a certain concentration, the two are placed in a beaker and stirred evenly, and the product is repeatedly washed with an ethanol solution, and the hexadecyltrimethylammonium bromide macromolecular intercalated gangue is obtained after filtration.

[0030] More specifically, 8-10 g of coal gangue and 100-200 ml of methyl sulfoxide solution are selected, stirred at 60-70 ° C for 20-24 h, and the stirring speed is 300-500 r / min; the centrifugal speed is 4000-5000 r / min, the centrifugal time is 3-5 min, and finally dried at 60-70 ° C for 20-24 h to obtain direct intercalation coal gangue; 3-5 g of direct intercalation coal gangue and 80-100 ml of methanol are taken, magnetically stirred at 50-60 ° C for 20-24 h, and the stirring speed is 400-500 r / min, then centrifugal separation, the centrifugal speed is 4000~5000r / min, the centrifugal time is 3~5min, and finally drying at 60~70℃ for 20~24h to obtain methanol twice intercalated coal gangue; 3~5g of methanol twice intercalated coal gangue is mixed with 80~100ml of methanol solution of hexadecyltrimethylammonium bromide, magnetically stirred at 50~60℃ for 20~24h, the stirring speed is 400~500 r / min, then centrifugal separation, the centrifugal speed is 4000~5000r / min, the centrifugal time is 3~5min, and finally drying at 60~70℃ for 20~24h to obtain hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue.

[0031] Preferably, the coal gangue needs to be ground to 200-350 meshes; the mass ratio of dimethyl sulfoxide solution to water is 9:1-9:2; and 20 mg / L-30 mg / L of hexadecyltrimethylammonium bromide methanol solution.

[0032] The present invention introduces methacrylic acid functional monomer and phenol template for preliminary reaction when preparing intercalated coal gangue-based surface molecular imprinting adsorption material. Methacrylic acid is used to effectively modify the rich pore structure of intercalated coal gangue and form a moderate interaction with the phenol template molecule. After imprinting reaction and elution, the material can more easily form a matching pore structure with phenol.

[0033] Phenol, hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and methacrylic acid are dissolved in 25-35 mL acetonitrile solvent, nitrogen is introduced for 3-7 minutes and then sealed, and magnetic stirring is carried out at 20℃-30℃ for 1h-2h, with a stirring speed of 380-420r / min; then ethylene glycol dimethacrylate and azobisisobutyronitrile are added, nitrogen is introduced again for 3-5 minutes and then sealed, and magnetic stirring is carried out at 60℃-70℃ for 22h-24h, with a stirring speed of 380-420r / min. Phenol and methacrylic acid are modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0034] Among them, the mass ratio of intercalated coal gangue, phenol and methacrylic acid is (1~3): (0.5~1): (2~9); the mass ratio of ethylene glycol dimethacrylate and azobisisobutyronitrile is (0.5~1.5): (0.1~0.45).

[0035] Since phenol is easily soluble in a mixture of methanol and acetic acid, the present invention preferably uses a mixture of methanol and acetic acid (in a ratio of 9:1 to 9:2) as an eluent for eluting to remove the phenol template molecules on the imprinting reaction product. The washed imprinting reaction product is dried in a vacuum freeze dryer for 12 to 14 hours to obtain an intercalated coal gangue-based surface molecular imprinting adsorption material.

[0036] Example 1 Take 200 mesh coal gangue (see the attached scanning electron microscope analysis) Figure 1 a) 10g of the mixture is placed in a beaker, and dimethyl sulfoxide solution and water are prepared in a mass ratio of 9:1. Then 100ml of dimethyl sulfoxide solution is added, and the mixture is stirred at 60°C for 24h at a stirring speed of 300r / min. The mixture is centrifuged at a speed of 4000r / min for 3min. The precipitate is then placed in a drying oven and dried at 60°C for 24h to obtain directly intercalated coal gangue.

[0037] Take 5 g of directly intercalated coal gangue and 80 ml of methanol, magnetically stir at 60°C for 24 hours with a stirring speed of 400 r / min; centrifuge at a speed of 4000 r / min and a centrifugal time of 3 minutes; pour off the upper solution, and finally dry at 60°C for 20 hours to obtain methanol twice intercalated coal gangue.

[0038] Take 5g of methanol-intercalated coal gangue twice and mix it with 80ml of 20mg / L methanol solution of hexadecyltrimethylammonium bromide, place the two in a beaker and stir them magnetically at 50℃ for 24h, the stirring speed is 400r / min, centrifuge, the centrifugal speed is 5000r / min, and the centrifugal time is 5min; then wash the product repeatedly with ethanol solution, filter and dry it at 60℃ for 24h to obtain hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue (the scanning electron microscope analysis is shown in the attached figure). Figure 1 b) in the above.

[0039] Take 1g of phenol, 0.5g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and 4mL of methacrylic acid, dissolve them in 25mL of acetonitrile solvent, introduce nitrogen for 3min and then seal, and magnetically stir for 2h at 20℃ with a stirring speed of 380r / min; then add 1mL of ethylene glycol dimethacrylate and 0.15g of azobisisobutyronitrile, introduce nitrogen again for 3min and then seal, and magnetically stir for 22h at 70℃ with a stirring speed of 380r / min. Phenol and methacrylic acid are modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0040] A methanol / acetic acid mixture (ratio 9:1) was used as an eluent to remove the phenol template molecules on the imprinted reaction product. The washed imprinted reaction product was dried in a vacuum freeze dryer for 12 h to finally obtain the intercalated coal gangue-based surface molecular imprinted adsorption material (the scanning electron microscopy analysis of which is shown in the attached Figure 1 c) 0.2 g of intercalated coal gangue-based surface molecular imprinting adsorption material was taken and adsorbed with 20 mL of phenol solution with a mass concentration of 500 mg / L. The adsorbed solution samples were extracted at set times (5, 10, 15, 20, 30, 40, 60, 80, 100 and 120 min), and the phenol content was determined by ultraviolet spectroscopy to calculate the adsorption amount of intercalated coal gangue-based surface molecular imprinting adsorption material (the adsorption kinetics are shown in the attached figure). Figure 3 ).

[0041] Take 0.2g of intercalated coal gangue-based surface molecular imprinting adsorption material, 0.2g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue, and 0.2g of coal gangue, and place them in 20mL of phenol, hydroquinone and p-nitrophenol mixed solution, where the mass concentration of the three in the mixed solution is 500 mg / L. Extract the adsorbed solution sample within the set time of 60min, and determine the content of phenol, hydroquinone and p-nitrophenol by ultraviolet spectroscopy to calculate the selectivity of the adsorption material (the adsorption selectivity is shown in the attached Figure 3 ).

[0042] The intercalated gangue-based surface molecular imprinting adsorption material and the cetyltrimethylammonium bromide macromolecular intercalated gangue were filled into a fixed bed adsorption device (see Appendix Figure 4 ), where the height of the adsorption column is 3 cm. Under the condition that the inlet flow rate of coal chemical wastewater is 2 ml / min, the operation time is set to 300 min. Subsequently, the removal effect of the adsorption material on phenolic substances in coal chemical wastewater is measured and evaluated.

[0043] Scanning electron microscopy (see Appendix Figure 1) observation, it can be clearly seen that compared with coal gangue, the surface pores of the coal gangue intercalated with hexadecyltrimethylammonium bromide macromolecules are significantly larger, the roughness increases, and multiple small layers are attached. In addition, compared with the coal gangue intercalated with hexadecyltrimethylammonium bromide macromolecules, the surface of the intercalated coal gangue-based surface molecular imprinting adsorption material shows an obvious coating imprinting layer, and a large number of micropores appear.

[0044] By infrared spectroscopy analysis (see Appendix Figure 2 In a), we can clearly observe the increase of HO, CO and C=O functional groups, indicating that the modification of functional monomers and other substances has been successfully completed. In addition, the specific surface area and pore structure analysis of molecular imprinting materials on the surface of coal gangue and intercalated coal gangue are compared (see Appendix Figure 2 (b and c) The results show that the number of micropores suitable for the size of phenol molecules on the surface of the modified intercalated coal gangue molecular imprinting material is significantly increased.

[0045] Adsorption selectivity analysis (see Appendix Figure 3 ) showed that compared with hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue and ordinary coal gangue, the intercalated coal gangue-based surface molecular imprinting adsorption material had a significant selectivity for phenol.

[0046] Example 2 Take 8g of 300-mesh coal gangue in a beaker, prepare dimethyl sulfoxide solution and water in a mass ratio of 9:1, add 200ml of dimethyl sulfoxide solution, stir at 70℃ for 20h, and the stirring speed is 500r / min; centrifuge at a speed of 4500r / min and a centrifugal time of 5min; then place the precipitate in a drying oven and dry it at 60℃ for 24h to obtain directly intercalated coal gangue.

[0047] Take 4 g of directly intercalated coal gangue and 100 ml of methanol, magnetically stir at 50°C for 24 hours with a stirring speed of 500 r / min; centrifuge at a speed of 5000 r / min for 5 minutes; pour off the upper solution, and finally dry at 70°C for 24 hours to obtain methanol twice intercalated coal gangue.

[0048] Take 4g of methanol-intercalated coal gangue and mix it with 100ml of methanol solution of hexadecyltrimethylammonium bromide with a mass concentration of 30mg / L. Place the two in a beaker and stir magnetically for 20h at 60℃ with a stirring speed of 500r / min. Centrifuge at a speed of 5000r / min and a centrifugal time of 5min. Wash the product repeatedly with ethanol solution, filter and dry at 70℃ for 24h to obtain hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue.

[0049] 1.6g of phenol, 0.8g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and 3.2mL of methacrylic acid were dissolved in 25mL of acetonitrile solvent, nitrogen was introduced for 3min and then sealed, and magnetic stirring was performed at 30°C for 1h with a stirring speed of 380r / min; then 0.64mL of ethylene glycol dimethacrylate and 0.16g of azobisisobutyronitrile were added, nitrogen was introduced again for 3min and then sealed, and magnetic stirring was performed at 60°C for 24h with a stirring speed of 380r / min. Phenol and methacrylic acid were modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0050] A methanol / acetic acid mixture (ratio 9:2) was used as an eluent to remove the phenol template molecules on the imprinted reaction product. The washed imprinted reaction product was dried in a vacuum freeze dryer for 14 h to finally obtain a methacrylic acid intercalated coal gangue-based surface molecular imprinting adsorption material.

[0051] The intercalated gangue-based surface molecular imprinting adsorption material and the hexadecyltrimethylammonium bromide macromolecular intercalated gangue were filled into a fixed bed adsorption device, in which the height of the adsorption column was 3 cm. Under the condition that the inlet flow rate of coal chemical wastewater was 2ml / min, the operation time was set to 300min. Subsequently, the removal effect of the adsorption material on phenolic substances in coal chemical wastewater was measured and evaluated.

[0052] Example 3 Take 9g of 350-mesh coal gangue in a beaker, prepare dimethyl sulfoxide solution and water in a mass ratio of 9:2, add 150ml of dimethyl sulfoxide solution, stir at 65℃ for 22h, and the stirring speed is 400r / min; centrifuge at a speed of 5000r / min and a centrifugal time of 5min; then place the precipitate in a drying oven and dry it at 65℃ for 22h to obtain directly intercalated coal gangue.

[0053] Take 4 g of directly intercalated coal gangue and 90 ml of methanol, magnetically stir at 55°C for 20 hours with a stirring speed of 400 r / min; centrifuge at a speed of 4800 r / min for 5 minutes; pour off the upper solution, and finally dry at 65°C for 22 hours to obtain methanol twice intercalated coal gangue.

[0054] Take 5g of methanol-intercalated coal gangue and mix it with 90ml of 25mg / L methanol solution of hexadecyltrimethylammonium bromide, place the two in a beaker and stir magnetically for 22h at 55℃, the stirring speed is 400r / min, and centrifuge at a centrifugal speed of 4000r / min and the centrifugal time is 4min; then wash the product repeatedly with ethanol solution, filter and dry it at 70℃ for 22h to obtain hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue.

[0055] Take 2g of phenol, 1g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and 3mL of methacrylic acid and dissolve them in 30mL of acetonitrile solvent. After nitrogen is introduced for 5 minutes, it is sealed. It is magnetically stirred for 1.5 hours at 25°C and the stirring speed is 400r / min. Then add 0.5mL of ethylene glycol dimethacrylate and 0.18g of azobisisobutyronitrile, and nitrogen is introduced again for 4 minutes and then sealed. It is magnetically stirred for 23 hours at 65°C and the stirring speed is 400r / min. Phenol and methacrylic acid are modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0056] A methanol / acetic acid mixture (ratio 9:1.5) was used as an eluent to remove the phenol template molecules on the imprinted reaction product. The washed imprinted reaction product was dried in a vacuum freeze dryer for 12 hours to finally obtain a methacrylic acid intercalated coal gangue-based surface molecular imprinting adsorption material.

[0057] The intercalated gangue-based surface molecular imprinting adsorption material and the hexadecyltrimethylammonium bromide macromolecular intercalated gangue were filled into a fixed bed adsorption device, in which the height of the adsorption column was 3 cm. Under the condition that the inlet flow rate of coal chemical wastewater was 2ml / min, the operation time was set to 300min. Subsequently, the removal effect of the adsorption material on phenolic substances in coal chemical wastewater was measured and evaluated.

[0058] Example 4 Take 10g of 250-mesh coal gangue in a beaker, prepare dimethyl sulfoxide solution and water in a mass ratio of 9:2, add 150ml of dimethyl sulfoxide solution, stir at 70℃ for 24h, and the stirring speed is 500r / min; centrifuge at a speed of 5000r / min and a centrifugal time of 4min; then place the precipitate in a drying oven and dry it at 60℃ for 24h to obtain directly intercalated coal gangue.

[0059] Take 3g of directly intercalated coal gangue and 100ml of methanol, magnetically stir at 55°C for 22h with a stirring speed of 400r / min; centrifuge at a speed of 4800r / min for 3min; pour off the upper solution, and finally dry at 70°C for 20h to obtain methanol twice intercalated coal gangue.

[0060] Take 3g of methanol-intercalated coal gangue and mix it with 100ml of methanol solution of hexadecyltrimethylammonium bromide with a mass concentration of 25mg / L. Place the two in a beaker and stir magnetically for 24h at 60℃ with a stirring speed of 480r / min. Centrifuge at a centrifugal speed of 4500r / min and a centrifugal time of 3min. Wash the product repeatedly with ethanol solution, filter and dry at 66℃ for 20h to obtain hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue.

[0061] Take 1g of phenol, 0.5g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and 2mL of acrylic acid, dissolve them in 35mL of acetonitrile solvent, introduce nitrogen for 7min and seal it, and stir it magnetically for 2h at 20℃ with a stirring speed of 420r / min; then add 0.6mL of ethylene glycol dimethacrylate and 0.1g of azobisisobutyronitrile, introduce nitrogen again for 5min and seal it, and stir it magnetically for 22h at 60℃ with a stirring speed of 420r / min. Phenol and acrylic acid are modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0062] A methanol / acetic acid mixture (ratio 9:2) was used as an eluent to remove the phenol template molecules on the imprinted reaction product. The washed imprinted reaction product was dried in a vacuum freeze dryer for 14 h to finally obtain an acrylic acid intercalated coal gangue-based surface molecular imprinting adsorption material.

[0063] Take 0.2g acrylic acid intercalated coal gangue-based surface molecular imprinting adsorption material and 0.2g acrylic acid intercalated coal gangue-based surface molecular imprinting adsorption material, respectively, and place them in 20mL of phenol solution with a mass concentration of 500 mg / L for adsorption. Extract the adsorbed solution sample within the set time of 60min, and determine the phenol content by ultraviolet spectroscopy to calculate the selectivity of the adsorption material (its adsorption selectivity is shown in the attached Figure 4 ).

[0064] Example 5 Take 8g of 300-mesh coal gangue in a beaker, prepare dimethyl sulfoxide solution and water in a mass ratio of 9:1, add 120ml of dimethyl sulfoxide solution, stir at 60℃ for 24h, and the stirring speed is 400r / min; centrifuge at a speed of 5000r / min and a centrifugal time of 5min; then place the precipitate in a drying oven and dry it at 70℃ for 20h to obtain directly intercalated coal gangue.

[0065] Take 4 g of directly intercalated coal gangue and 100 ml of methanol, stir magnetically at 60°C for 20 hours at a stirring speed of 450 r / min; centrifuge at a speed of 5000 r / min for 4 minutes; pour off the upper solution, and finally dry at 60°C for 24 hours to obtain methanol twice intercalated coal gangue.

[0066] Take 5g of methanol-intercalated coal gangue and mix it with 90ml of methanol solution of hexadecyltrimethylammonium bromide with a mass concentration of 24mg / L. Place the two in a beaker and stir magnetically for 20h at 50℃ with a stirring speed of 450r / min. Centrifuge at a centrifugal speed of 4500r / min and a centrifugal time of 3min. Wash the product repeatedly with ethanol solution, filter and dry at 65℃ for 20h to obtain hexadecyltrimethylammonium bromide macromolecule intercalated coal gangue.

[0067] Take 3g of phenol, 1g of hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue and 9mL of methacrylamide, dissolve them in 35mL of acetonitrile solvent, introduce nitrogen for 7min and seal it, and stir magnetically for 1h at 25℃ with a stirring speed of 420r / min; then add 1.5mL of ethylene glycol dimethacrylate and 0.45g of azobisisobutyronitrile, introduce nitrogen again for 5min and seal it, and stir magnetically for 22h at 70℃ with a stirring speed of 420r / min. Phenol and methacrylamide are modified near the pores of the intercalated coal gangue to obtain an imprinted product.

[0068] A methanol / acetic acid mixture (ratio 9:1) was used as an eluent to remove the phenol template molecules on the imprinted reaction product. The washed imprinted reaction product was dried in a vacuum freeze dryer for 12 h to finally obtain a methacrylamide intercalated coal gangue-based surface molecular imprinting adsorption material.

[0069] Take 0.2g of methacrylamide intercalated coal gangue-based surface molecular imprinting adsorption material and 0.2g of methacrylamide intercalated coal gangue-based surface molecular imprinting adsorption material, respectively, and place them in 20mL of phenol solution with a mass concentration of 500 mg / L for adsorption. Extract the adsorbed solution sample within the set time of 60min, and determine the phenol content by ultraviolet spectroscopy to calculate the selectivity of the adsorption material (the adsorption selectivity is shown in the attached Figure 4 ).

[0070] Table 1 Adsorption effect of gangue-based surface molecularly imprinted adsorption materials prepared in Examples 1-5 on phenols

[0071] It can be seen from Table 1 above that the gangue-based surface molecular imprinting adsorption material prepared in Example 1 has the best selective adsorption effect on phenols, wherein the adsorption capacities of p-phenol, hydroquinone and p-nitrophenol are 73.55 mg / g, 41.32 mg / g and 36.18 mg / g respectively.

[0072] Advantages of the present invention: (1) Optimized intercalation process and imprinting effect: The interlayer spacing of the material was significantly increased through a three-step intercalation process, significantly improving its adsorption capacity. Using this enhanced structure as a carrier for molecular imprinting, the adsorption efficiency of phenol pollutants was greatly improved, showing excellent removal effect.

[0073] (2) Superior selective adsorption performance: The intercalated coal gangue after molecular imprinting treatment showed excellent selective adsorption ability in mixed solutions of various phenols such as phenol, hydroquinone and p-nitrophenol, showing higher application value and broad application prospects.

[0074] (3) High-efficiency separation capability in complex environments: The intercalated gangue-based molecular imprinting adsorption material can still achieve specific adsorption of phenol in complex coal chemical wastewater systems, ensuring accurate separation and efficient recovery of phenol. This technology provides an efficient and environmentally friendly solution for treating complex wastewater systems, and helps promote the development of green chemical processes.

[0075] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an intercalated coal gangue-based surface molecularly imprinted adsorption material, characterized in that: include: Using coal gangue as raw material, intercalation reaction occurs in a solution containing an intercalation agent, and intercalated coal gangue is formed through centrifugal separation and drying; Using intercalated coal gangue as a carrier, phenol and methacrylic acid are added to acetonitrile solvent under an inert atmosphere for a preliminary reaction, and then a cross-linking agent and an initiator are added for a surface imprinting reaction to obtain an imprinting reaction product; The imprinting reaction product is treated to obtain intercalated coal gangue-based surface molecular imprinting adsorption material.

2. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 1, characterized in that: The intercalation reactions include direct intercalation of dimethyl sulfoxide, double intercalation of methanol and macromolecular intercalation of hexadecyltrimethylammonium bromide.

3. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 2, characterized in that: The intercalated coal gangue is mixed with a dimethyl sulfoxide intercalation agent solution, magnetically stirred under heating conditions, and then centrifuged and dried to obtain the directly intercalated coal gangue; Directly intercalated coal gangue and methanol solution are subjected to magnetic stirring under heating conditions, centrifuged, and the upper layer solution is poured off to obtain methanol twice intercalated coal gangue; The coal gangue intercalated with methanol twice is mixed with the methanol solution of hexadecyltrimethylammonium bromide, the two are stirred evenly, and the product is repeatedly washed with an ethanol solution, and the hexadecyltrimethylammonium bromide macromolecular intercalated coal gangue is obtained after suction filtration.

4. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 3, characterized in that: The gangue and methyl sulfoxide solution are stirred at 60°C to 70°C for 20h to 24h, with a stirring speed of 300r / min-500r / min; the centrifugal speed is 4000r / min to 5000r / min, and the centrifugal time is 3min to 5min. Finally, the mixture is dried at 60°C to 70°C for 20h to 24h to obtain directly intercalated gangue; wherein the addition ratio of gangue to methyl sulfoxide solution is 8g to 10g: 100ml to 200ml; Direct intercalation coal gangue and methanol are magnetically stirred at 50°C to 60°C for 20h to 24h, then centrifuged at a centrifugal speed of 4000r / min to 5000r / min for 3min to 5min, and finally dried at 60°C to 70°C for 20h to 24h to obtain methanol twice intercalated coal gangue; wherein the amount ratio of direct intercalation coal gangue to methanol is 3g to 5g: 80ml to 100ml; The coal gangue intercalated with methanol twice is mixed with a methanol solution of hexadecyltrimethylammonium bromide, and magnetically stirred at 50°C to 60°C for 20h to 24h, and then centrifuged at a centrifugal speed of 4000r / min to 5000r / min for 3min to 5min, and finally dried at 60°C to 70°C for 20h to 24h to obtain the coal gangue intercalated with hexadecyltrimethylammonium bromide macromolecules; The usage ratio of the methanol twice intercalated coal gangue to the methanol solution of hexadecyltrimethylammonium bromide is 3g-5g:80-100ml.

5. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 3, characterized in that: The coal gangue needs to be ground to 200-350 meshes and calcined at 700-800°C; the mass ratio of dimethyl sulfoxide solution to water is 9:1-9:2; the concentration of the methanol solution of hexadecyltrimethylammonium bromide is 20 mg / L-30 mg / L.

6. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 1, characterized in that: In the preliminary reaction process: the mass ratio of intercalated coal gangue, phenol and methacrylic acid is (1-3): (0.5-1): (2-9); the reaction temperature is controlled at 20°C-30°C, and the reaction time is 1h-2h.

7. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 1, characterized in that: During the surface imprinting reaction process: the crosslinking agent is ethylene glycol dimethacrylate, the initiator is azobisisobutyronitrile; the mass ratio of ethylene glycol dimethacrylate and azobisisobutyronitrile is (0.5-1.5): (0.1-0.45); the reaction temperature is controlled at 60°C-70°C, and the reaction time is 22h-24h.

8. The method for preparing the intercalated coal gangue-based surface molecularly imprinted adsorption material according to claim 1, characterized in that: The imprinting reaction product is processed to obtain the intercalated coal gangue-based surface molecular imprinting adsorption material, specifically: The imprinted reaction product is washed with a mixture of methanol and acetic acid as an eluent to remove the phenol template molecules on the imprinted reaction product; the washed imprinted reaction product is dried to obtain an intercalated coal gangue-based surface molecular imprinting adsorption material.

9. The method for preparing the intercalated gangue-based surface molecularly imprinted adsorption material according to claim 8, characterized in that: The volume ratio of methanol to acetic acid is 9:1 to 9:2, and the washed imprinting reaction product is dried for 12 h to 14 h.

10. An intercalated coal gangue-based surface molecular imprinting adsorption material, characterized in that: The method is prepared by any one of claims 1 to 9.

Images