A cyano-functionalized ultra-high crosslinked polystyrene resin, its preparation method and application

Abstract

The application provides a cyan-functionalized hypercrosslinked polystyrene resin and a preparation method and application thereof, and belongs to the technical field of adsorption resins for treating explosive wastewater. The application uses chloromethylated polystyrene resin as raw material, and successfully prepares a functionalized secondary crosslinked resin by taking twice Friedel-Crafts alkylation reaction as a core reaction, which comprises the following steps: the first step is to make the resin internally crosslinked and perform cyan-functionalized modification; and the second step is to perform crosslinking under the action of an external crosslinking agent and make the resin internally further crosslinked. The prepared secondary crosslinked resin not only realizes cyan-functionalization, but also maintains a high specific surface area and forms a hierarchical pore structure mainly composed of micropores. The cyan-functionalized hypercrosslinked polystyrene resin can selectively adsorb RDX in a solution through electrostatic interaction and hydrogen bond, exhibits high adsorption capacity and rapid adsorption removal effect, and has a wide application prospect for treating explosive wastewater containing RDX.

Description

Technical Field

[0001] This invention relates to the field of adsorption resin technology for treating explosive wastewater, and particularly to a cyano-functionalized ultra-high crosslinked polystyrene resin, its preparation method, and its application. Background Technology

[0002] RDX (Rexin) is a high-energy explosive used in a variety of military and other applications, such as nuclear devices, rocket propellants, plastic explosives, rocket fuel, detonators, construction, quarrying, and mining. The indiscriminate disposal of RDX waste from production sites, blasting sites, and unexploded ordnance has led to severe environmental pollution of soil and water bodies. Adsorption is a simple and effective method, and one of the most efficient technologies for RDX removal.

[0003] Ultra-highly cross-linked polymers have a high BET surface area (S BET With their good porosity and diverse functionalities, microporous organic polymers are considered excellent adsorbents for organic pollutants. In recent years, novel microporous organic polymers prepared using ultra-high crosslinking technology have demonstrated superior performance in gas capture and storage, removal of aromatic organic compounds, and recovery of heavy metals. For example, HPVE-04, HPVE-13, and HPVE-40 have been shown to effectively adsorb phenol, p-nitrophenol, and rhodamine B, respectively.

[0004] Macroporous, low-crosslinked chloromethylated polystyrene resin is a common raw material for the production of ultra-highly crosslinked polymers. It is obtained through the traditional Friedel-Crafts reaction. Under the catalysis of a Lewis acid, the side-chain -CH2Cl group acts as an electrophile, undergoing an electrophilic substitution reaction with adjacent phenyl groups. Numerous methylene groups act as crosslinking bridges connecting adjacent phenyl groups, resulting in S... BET The rapid increase and formation of microporous structures are significant factors. While general hypercrosslinked resins exhibit good adsorption effects on various organic compounds, the organic wastewater generated during RDX production typically contains ethyl acetate, acetone, and small amounts of RDX. Traditional hypercrosslinked resins tend to effectively adsorb organic compounds with high content of ethyl acetate and acetone, but their adsorption effect on relatively low-content RDX is poor, resulting in the need for large amounts of adsorbent to achieve the desired RDX removal effect. Therefore, developing a novel functionalized hypercrosslinked resin with selective adsorption of RDX is of significant practical importance. Summary of the Invention

[0005] The purpose of this invention is to provide a cyano-functionalized ultra-high crosslinked polystyrene resin, its preparation method, and its application, in order to solve the technical problem of poor adsorption effect of existing adsorbents on RDX.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing cyano-functionalized ultra-high crosslinked polystyrene resin, comprising the following steps:

[0008] 1) Chloromethylated polystyrene resin is added to an organic solvent containing aromatic nitrile for swelling, and then alkylation reaction is carried out under the action of a catalyst to obtain cyanofunctionalized polystyrene resin.

[0009] 2) The cyano-functionalized polystyrene resin was swollen in an organic solvent, and then a catalyst was added to obtain a mixture;

[0010] 3) Once the temperature of the mixture reaches the target temperature, add an organic solvent containing an external crosslinking agent to the mixture to carry out a crosslinking reaction, thereby obtaining cyano-functionalized ultra-high crosslinked polystyrene resin.

[0011] Furthermore, the aromatic nitrile is an aromatic compound containing a cyano group;

[0012] In step 1), the mass ratio of the aromatic nitrile to the chloromethylated polystyrene resin is 1:10-20, the volume-to-mass ratio of the organic solvent to the chloromethylated polystyrene resin is 10-40 mL:1 g, and the mass ratio of the catalyst to the chloromethylated polystyrene resin is 1:3-4.

[0013] Furthermore, in step 1), the swelling time is 8–10 h, the alkylation reaction temperature is 45–85 °C, and the alkylation reaction time is 8–18 h.

[0014] Furthermore, the external crosslinking agent comprises one or more of dimethylformaldehyde, p-dichlorobenzyl, and biphenyl dichlorobenzyl.

[0015] Furthermore, in step 2), the volume-to-mass ratio of the organic solvent to the cyanofunctionalized polystyrene resin is 10-20 mL: 1 g; and the mass ratio of the catalyst to the cyanofunctionalized polystyrene resin is 1: 1-2.

[0016] Furthermore, in step 3), the target temperature is 45–85°C, and the crosslinking reaction time is 8–18 h.

[0017] Furthermore, the mass ratio of the external crosslinking agent to the cyanofunctionalized polystyrene resin is 0.3–1.5:1;

[0018] In step 3), the mass-volume ratio of the external crosslinking agent to the organic solvent is 0.3–1.5 g: 10–20 mL.

[0019] Furthermore, in steps 1) and 2), the catalyst independently comprises one or more of anhydrous ferric chloride, anhydrous aluminum chloride, anhydrous zinc chloride, and anhydrous titanium chloride.

[0020] In steps 1), 2), and 3), the organic solvent independently includes one or more of dichloromethane, 1,2-dichloroethane, nitromethane, nitrobenzene, and carbon disulfide.

[0021] This invention provides a cyano-functionalized ultra-high crosslinked polystyrene resin.

[0022] This invention also provides an application of cyano-functionalized ultra-high crosslinked polystyrene resin as an adsorbent in explosives wastewater.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention selects inexpensive and readily available chloromethylated polystyrene resin as raw material, and achieves the synthesis of ultra-high crosslinked polymers through the mature Friedel-Crafts alkylation reaction. The whole process is simple to operate, and the required reagents can be purchased directly, which has economic benefits and direct commercial application value.

[0025] 2. This invention utilizes the electrostatic interaction and weak hydrogen bonds formed between cyano groups and RDX to innovatively prepare cyano-functionalized ultra-high crosslinked polystyrene adsorption resin, thereby improving the adsorption effect of RDX in explosive wastewater.

[0026] 3. This invention introduces an external crosslinking agent through secondary crosslinking, and makes the internal crosslinking of the resin more thorough, further increasing the specific surface area of ​​the resin, compensating for the reduction in specific surface area caused by functionalization, and improving the adsorption effect. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the preparation process of the cyano-functionalized ultra-high crosslinked polystyrene adsorption resin in this invention.

[0028] Figure 2 The N2 adsorption-desorption isotherms and pore size distribution diagrams of the various resins involved in this invention are shown.

[0029] Figure 3 Fourier transform infrared spectra of various resins involved in this invention;

[0030] Figure 4 The curves showing the adsorption rate of RDX by the secondary crosslinking resin (biphenyl dichlorobenzyl) in this invention over time and the kinetic fitting curves are shown.

[0031] Figure 5 The curves showing the adsorption rate of RDX by the secondary crosslinking resin (benzyl dichlorobenzyl) in this invention over time and the kinetic fitting curves are shown.

[0032] Figure 6The curves showing the adsorption rate of RDX by the secondary crosslinking resin (dimethylformaldehyde) in this invention over time and the kinetic fitting curves are shown. Detailed Implementation

[0033] This invention provides a method for preparing cyano-functionalized ultra-high crosslinked polystyrene resin, comprising the following steps:

[0034] 1) Chloromethylated polystyrene resin is added to an organic solvent containing aromatic nitrile for swelling, and then alkylation reaction is carried out under the action of a catalyst to obtain cyanofunctionalized polystyrene resin.

[0035] 2) The cyano-functionalized polystyrene resin was swollen in an organic solvent, and then a catalyst was added to obtain a mixture;

[0036] 3) Once the temperature of the mixture reaches the target temperature, add an organic solvent containing an external crosslinking agent to the mixture to carry out a crosslinking reaction, thereby obtaining cyano-functionalized ultra-high crosslinked polystyrene resin.

[0037] In this invention, the chloromethylated polystyrene resin is passed through a 20-40 mesh sieve, preferably a 30 mesh sieve, before swelling.

[0038] In this invention, the aromatic nitrile is an aromatic compound containing a cyano group, preferably one or more of benzonitrile, terephthalonitrile, o-phthalonitrile, isophthalonitrile and phenylacetonitrile, and more preferably one or more of benzonitrile, terephthalonitrile and o-phthalonitrile.

[0039] In this invention, in step 1), the mass ratio of the aromatic nitrile to the chloromethylated polystyrene resin is 1:10-20, preferably 1:12-18, and more preferably 1:15; the volume-mass ratio of the organic solvent to the chloromethylated polystyrene resin is 10-40 mL:1 g, preferably 15-35 mL:1 g, and more preferably 20-30 mL:1 g; the mass ratio of the catalyst to the chloromethylated polystyrene resin is 1:3-4, preferably 1:3.5.

[0040] In this invention, in step 1), the swelling time is 8-10 hours, preferably 9 hours; the alkylation reaction temperature is 45-85°C, preferably 50-80°C, and more preferably 60-70°C; the alkylation reaction time is 8-18 hours, preferably 10-15 hours, and more preferably 12-14 hours.

[0041] In this invention, the external crosslinking agent comprises one or more of dimethylformaldehyde, p-dichlorobenzyl, and biphenyl dichlorobenzyl, preferably biphenyl dichlorobenzyl.

[0042] In this invention, in step 2), the volume-to-mass ratio of the organic solvent to the cyanofunctionalized polystyrene resin is 10-20 mL:1 g, preferably 12-18 mL:1 g, and more preferably 15 mL:1 g; the mass ratio of the catalyst to the cyanofunctionalized polystyrene resin is 1:1-2, preferably 1:1.5.

[0043] In this invention, in step 3), the target temperature is 45-85°C, preferably 50-80°C, and more preferably 60-70°C; the crosslinking reaction time is 8-18h, preferably 10-15h, and more preferably 12-13h.

[0044] In this invention, the mass ratio of the external crosslinking agent to the cyanofunctionalized polystyrene resin is 0.3–1.5:1, preferably 0.5–1.2:1, and more preferably 0.8–1.0:1;

[0045] In step 3), the mass-volume ratio of the external crosslinking agent to the organic solvent is 0.3-1.5g:10-20mL, preferably 0.5-1.2g:12-18mL, and more preferably 0.8-1.0g:14-16mL.

[0046] In this invention, in steps 1) and 2), the catalyst independently comprises one or more of anhydrous ferric chloride, anhydrous aluminum chloride, anhydrous zinc chloride and anhydrous titanium chloride, preferably anhydrous ferric chloride.

[0047] In steps 1), 2), and 3), the organic solvent independently includes one or more of dichloromethane, 1,2-dichloroethane, nitromethane, nitrobenzene, and carbon disulfide, preferably 1,2-dichloroethane.

[0048] In this invention, in step 1), after the alkylation reaction, the obtained product is washed several times with anhydrous ethanol and 1% hydrochloric acid, and then the resin is extracted with a Soxhlet extractor at 80-120°C until it is completely clean. The resin is then vacuum dried at 60-80°C for 12-24 hours to obtain cyanofunctionalized polystyrene resin.

[0049] In this invention, in step 3), after the crosslinking reaction, the obtained product is washed several times with anhydrous ethanol and 1% hydrochloric acid, and then the resin is extracted with a Soxhlet extractor at 80-120°C until it is completely clean. The resin is then vacuum dried at 60-80°C for 12-24 hours to obtain cyano-functionalized ultra-high crosslinked polystyrene resin.

[0050] In this invention, the solvent in the Soxhlet extractor comprises one or more of methanol, ethanol, acetone and 1,2-dichloroethane, preferably methanol.

[0051] This invention provides a cyano-functionalized ultra-high crosslinked polystyrene resin.

[0052] This invention also provides an application of cyano-functionalized ultra-high crosslinked polystyrene resin as an adsorbent in explosives wastewater.

[0053] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] 1) Functionalization and internal cross-linking:

[0056] First, the chloromethylated polystyrene resin was passed through a 30-mesh sieve. Then, 0.75 g of benzonitrile was dissolved in 150 mL of 1,2-dichloroethane at room temperature, followed by the addition of 15 g of the chloromethylated polystyrene resin, allowing it to swell in the mixed solution for 10 h. Under mechanical stirring, 4.0 g of anhydrous FeCl3 was rapidly added to the reaction mixture, and the temperature of the reaction mixture was raised to 85 °C and maintained for 8 h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted using a Soxhlet extractor at 120 °C until completely clean. The resin was then vacuum dried at 60 °C for 24 h to obtain cyano-functionalized polystyrene resin, abbreviated as cyano resin.

[0057] 2) External crosslinking and further internal crosslinking;

[0058] The above-mentioned 2g of cyano resin was added to 20mL of 1,2-dichloroethane and swollen for 10h. 1.6g of anhydrous FeCl3 was added at room temperature and mechanically stirred until completely dissolved. Once the reaction mixture reached 85℃, 20mL of 1,2-dichloroethane solution containing 2.512g of biphenyl dichlorobenzyl was quickly poured into a three-necked flask containing the reactants, and the mixture was refluxed for 8h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted thoroughly using a Soxhlet extractor at 120℃. The resin was then vacuum dried at 60℃ for 24h to obtain a secondary crosslinked cyano-functionalized ultra-high crosslinked polystyrene resin (external crosslinking agent: biphenyl dichlorobenzyl), abbreviated as secondary crosslinked resin (biphenyl dichlorobenzyl).

[0059] The BET specific surface area S of this resin BET 970.23m 2 / g, microporosity S micro / S BET It is 92.51%, BJH pore volume V BJH 0.35m 3 / g, average pore size D avg It is 5.77nm.

[0060] Adsorption kinetics experiment:

[0061] A series of RDX solutions with a concentration of 20 mg / L and a pH of 7 were precisely prepared using volumetric flasks. The amount of secondary cross-linking resin (biphenyl dichlorobenzyl) was 2 g / L. The solutions were placed in a constant temperature shaker at 30 °C and a rotation speed of 180 r / min for 3 h for adsorption reaction. Afterward, the solutions were filtered through a syringe with a 0.22 μm filter. The concentration of RDX (mg / L) in the sample solution collected at different time points was determined using high performance liquid chromatography (HPLC). The measured peak height and peak area were substituted into the regression equation to obtain the concentration of RDX in the sample solution at that time point (mg / L).

[0062] like Figure 4 As shown, the pseudo-first-order kinetic constant k1 of this adsorption experiment is 0.1040 min. –1 The adsorption capacity q was calculated using a pseudo-first-order kinetic model. cal,1 The value was 7.96 mg / g, with a correlation coefficient R1. 2 The value is 0.88; the pseudo-second-order kinetic constant k2 is 0.0199 g / (mgmin), and the adsorption capacity q is calculated using the pseudo-second-order kinetic model. cal,2 The value was 8.60 mg / g, with a correlation coefficient R². 2 The value is 0.95. Clearly, the pseudo-second-order dynamic model has a better fit.

[0063] Example 2

[0064] 1) Functionalization and internal cross-linking:

[0065] First, the chloromethylated polystyrene resin was passed through a 30-mesh sieve. Then, 1.5 g of benzonitrile was dissolved in 150 mL of 1,2-dichloroethane at room temperature, followed by the addition of 15 g of the chloromethylated polystyrene resin, allowing it to swell in the mixed solution for 10 h. Under mechanical stirring, 4.0 g of anhydrous FeCl3 was rapidly added to the reaction mixture, and the temperature of the reaction mixture was raised to 85 °C and maintained for 8 h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted using a Soxhlet extractor at 120 °C until completely clean. The resin was then vacuum dried at 60 °C for 24 h to obtain cyano-functionalized polystyrene resin, abbreviated as cyano resin.

[0066] 2) External crosslinking and further internal crosslinking:

[0067] The above-mentioned 2g of cyano resin was added to 20mL of 1,2-dichloroethane and swollen for 10h. 1.6g of anhydrous FeCl3 was added at room temperature and mechanically stirred until completely dissolved. Once the reaction mixture reached 85℃, 20mL of 1,2-dichloroethane solution containing 1.75g ​​of p-dichlorobenzyl was quickly poured into a three-necked flask containing the reactants, and the mixture was refluxed for 8h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted thoroughly using a Soxhlet extractor at 120℃. The resin was then vacuum dried at 60℃ for 24h to obtain a secondary crosslinked cyano-functionalized ultra-high crosslinked polystyrene resin (external crosslinking agent: p-dichlorobenzyl), abbreviated as secondary crosslinked resin (p-dichlorobenzyl).

[0068] The BET specific surface area S of this resin BET It is 850.09m 2 / g, microporosity S micro / S BET It is 92.81%, BJH pore volume V BJH It is 0.27m 3 / g, average pore size D avg It is 4.97nm.

[0069] Adsorption kinetics experiment:

[0070] A series of RDX solutions with a concentration of 20 mg / L and a pH of 7 were precisely prepared using volumetric flasks. The amount of secondary crosslinking resin (benzyl dichloroisocyanurate) was 2 g / L. The solutions were placed in a constant temperature shaker at 30 °C and a rotation speed of 180 r / min for 3 h for adsorption reaction. Afterward, the solutions were filtered through a syringe with a 0.22 μm filter. The concentration of RDX in the sample solution collected at different time points was determined by high performance liquid chromatography (HPLC). The measured peak height and peak area were substituted into the regression equation to obtain the concentration of RDX in the sample solution at that time point (mg / L).

[0071] like Figure 5 As shown, the pseudo-first-order kinetic constant k1 of this adsorption experiment is 0.0898 min. –1 The adsorption capacity q was calculated using a pseudo-first-order kinetic model. cal,1 The value was 7.52 mg / g, with a correlation coefficient R1. 2 The value is 0.85; the pseudo-second-order kinetic constant k2 is 0.0183 g / (mgmin), and the adsorption capacity q is calculated using the pseudo-second-order kinetic model. cal,2 The value was 8.13 mg / g, with a correlation coefficient R². 2 The value is 0.93. Clearly, the pseudo-second-order dynamic model has a better fit.

[0072] Example 3

[0073] 1) Functionalization and internal cross-linking:

[0074] First, the chloromethylated polystyrene resin was passed through a 30-mesh sieve. Then, 2.25 g of benzonitrile was dissolved in 150 mL of 1,2-dichloroethane at room temperature, followed by the addition of 15 g of the chloromethylated polystyrene resin, allowing it to swell in the mixed solution for 10 h. Under mechanical stirring, 4.0 g of anhydrous FeCl3 was rapidly added to the reaction mixture, and the temperature of the reaction mixture was raised to 85 °C and maintained for 8 h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted using a Soxhlet extractor at 120 °C until completely clean. The resin was then vacuum dried at 60 °C for 24 h to obtain cyano-functionalized polystyrene resin, abbreviated as cyano resin.

[0075] 2) External crosslinking and further internal crosslinking:

[0076] The above 2g of cyano resin was added to 20mL of 1,2-dichloroethane and swollen for 10h. 1.6g of anhydrous FeCl3 was added at room temperature and mechanically stirred until completely dissolved. Once the reaction mixture reached 85℃, 20mL of 1,2-dichloroethane solution containing 0.762g of dimethyl formaldehyde was quickly poured into a three-necked flask containing the reactants, and the mixture was refluxed for 8h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted thoroughly using a Soxhlet extractor at 120℃. The resin was then vacuum dried at 60℃ for 24h to obtain a secondary crosslinked cyano-functionalized ultra-high crosslinked polystyrene resin (external crosslinking agent: dimethyl formaldehyde), abbreviated as secondary crosslinked resin (dimethyl formaldehyde).

[0077] The BET specific surface area S of this resin BET It is 891.06m 2 / g, microporosity S micro / S BET It is 93.13%, BJH pore volume V BJH It is 0.31m 3 / g, average pore size D avg It is 5.73nm.

[0078] Adsorption kinetics experiment:

[0079] A series of RDX solutions with a concentration of 20 mg / L and a pH of 7 were precisely prepared using volumetric flasks. The amount of secondary cross-linking resin (dimethylformaldehyde) was 2 g / L. The solutions were placed in a constant temperature shaker at 30 °C and a rotation speed of 180 r / min for 3 h for adsorption reaction. Afterward, the solutions were filtered through a syringe with a 0.22 μm filter. The concentration of RDX (mg / L) in the sample solution collected at different time points was determined using high performance liquid chromatography (HPLC). The measured peak height and peak area were substituted into the regression equation to obtain the concentration of RDX in the sample solution at that time point (mg / L).

[0080] like Figure 6As shown, the pseudo-first-order kinetic constant k1 of this adsorption experiment is 0.1284 min. –1 The adsorption capacity q was calculated using a pseudo-first-order kinetic model. cal,1 The value was 8.61 mg / g, with a correlation coefficient R1. 2 The value is 0.96; the pseudo-second-order kinetic constant k2 is 0.0211 g / (mgmin), and the adsorption capacity q is calculated using the pseudo-second-order kinetic model. cal,2 The value was 9.34 mg / g, with a correlation coefficient R². 2 The value is 0.99. Clearly, the pseudo-second-order dynamic model has a better fit.

[0081] Comparative Example 1

[0082] First, the chloromethylated polystyrene resin was passed through a 30-mesh sieve. Then, 15g of the chloromethylated polystyrene resin was swollen in 150mL of 1,2-dichloroethane for 10h. Under mechanical stirring, 4.0g of anhydrous FeCl3 was rapidly added to the mixture, and the reaction temperature was raised to 85℃ and maintained for 8h. The resulting resin particles were filtered, washed several times with anhydrous ethanol and 1% hydrochloric acid, and then extracted with a Soxhlet extractor at 120℃ until completely clean. The resin was then vacuum dried at 60℃ for 24h to obtain non-functionalized ultra-high crosslinked polystyrene resin.

[0083] Validation of the structure of cyano-functionalized ultra-highly crosslinked polystyrene adsorption resin

[0084] The present invention describes the physical and chemical structures of the six resins involved using two characterization methods:

[0085] 1. BET specific surface area and BJH pore size distribution

[0086] like Figure 2 As shown, the S of the raw material chloromethylated polystyrene resin BET It is 31.55m 2 / g( Figure 2 a) The S of the ultra-highly crosslinked resin obtained by direct crosslinking without the addition of any modifier (Comparative Example 1) BET It is 1084.11m 2 / g( Figure 2 b) This demonstrates that the use of ultra-high crosslinking technology can indeed greatly increase the S content of the resin. BET S of cyano resin BET It is 803.59m 2 / g( Figure 2 c) The S value is lower than that of ultra-high crosslinked resins, but still remains relatively high. This is because the introduction of benzonitrile reacts with some -CH2Cl, leading to a decrease in the crosslinking rate. The S values ​​of three secondary crosslinked resins obtained using different external crosslinking agents are shown in the figures. BETThere has been a rebound, especially in secondary crosslinking resins (biphenyl dichlorobenzyl), S BET The increase of 20.7% compared to cyano resin indicates that the external crosslinking agent can enhance the S content of the resin. BET This process further increases the cross-linking capacity and makes the internal cross-linking more thorough. Furthermore, compared to chloromethylated polystyrene resin, the resin exhibits a significant increase in pore volume and a decrease in pore size during the hyper-cross-linking process, and the introduction of modifiers does not alter this trend.

[0087] 2. Fourier Transform Infrared Spectroscopy (FT-IR)

[0088] like Figure 3 As shown, at 1267cm –1 The absorption peak at 2920 cm⁻¹ corresponds to the -CH₂Cl stretching vibration, and its intensity gradually decreases with increasing crosslinking number, indicating an increased degree of crosslinking. –1 The absorption peak at 2335 cm⁻¹ is related to the methylene bridge (-CH₂-) formed between the linked aromatic rings in the Friedel-Crafts alkylation reaction. Notably, the peak at 2335 cm⁻¹ is also significant. –1 The characteristic absorption peak at 3018 cm⁻¹ is related to the C≡N stretching vibration, indicating successful resin modification. Additionally, the peak at 3018 cm⁻¹... –1 The absorption peak at this point is the stretching vibration peak of the CH bond in the benzene ring, and the secondary crosslinked resin (biphenyl dichlorobenzyl) exhibits the highest strength, proving the successful introduction of the external crosslinking agent.

[0089] Through the above embodiments, a series of cyano-functionalized ultra-high crosslinked polystyrene adsorption resins with high specific surface area and adsorption capacity were prepared. Table 1 shows the comparison of specific surface area, actual adsorption capacity and calculated adsorption capacity of each embodiment.

[0090] Table 1 Comparison of specific surface area, actual adsorption capacity, and calculated adsorption capacity for each embodiment.

[0091]

[0092]

[0093] Experimental Example

[0094] Applications of cyano-functionalized ultra-high crosslinked polystyrene adsorption resins

[0095] The adsorption performance of the cyano-functionalized ultra-high crosslinked polystyrene adsorbent resin for RDX obtained in the examples was experimentally tested, and the specific steps are as follows:

[0096] 1) Preparation of RDX standard solution: Accurately weigh a certain amount of RDX (analytical grade), dissolve it in a small amount of acetone to form a saturated solution, quantitatively transfer it to a volumetric flask with deionized water, and dilute to volume. This solution is the RDX standard stock solution. Before use, dilute with deionized water to a 60 mg / L RDX standard solution.

[0097] 2) Construction of RDX standard curve: Take 5–7 volumetric flasks and dilute the RDX standard solution with deionized water to prepare a series of RDX standard solutions with concentrations ranging from 0.0 mg / L to 60.0 mg / L. Adjust the high-performance liquid chromatograph to the optimal measurement state and set the instrument parameters (measurement wavelength: 210 nm; chromatographic column: 250 mm × 4.6 mm × 5 μm, CL). 18 Column temperature: 25℃; Mobile phase: methanol:water = 60:40 (V / V); Mobile phase flow rate: 1.0 mL / min; Inject 10 μL of sample and determine the peak height or peak area of ​​each concentration of the standard solution series. Plot a standard curve against the corresponding RDX concentration (mg / L) using the measured peak height or peak area and calculate the regression equation. The correlation coefficient should be ≥0.999.

[0098] 3) Adsorption kinetics experiment: A series of RDX solutions with concentrations of 10–60 mg / L and pH values ​​of 2–11 were precisely prepared using volumetric flasks. The amount of secondary crosslinking resin used was 2–4 g / L. The solutions were placed in a constant-temperature shaker at 20–40℃ and a rotation speed of 120–220 r / min for 3–6 h for adsorption. Afterward, the solutions were filtered through a syringe with a 0.20–0.24 μm filter. High-performance liquid chromatography (HPLC) was used to determine the concentration of RDX (mg / L) in the sample solution at different time points. The measured peak height and peak area were substituted into the regression equation to obtain the concentration of RDX in the sample solution at that time point. The experimental results are as follows: Figures 4 to 6 .

[0099] As can be seen from the above embodiments, the present invention provides a cyano-functionalized ultra-highly cross-linked polystyrene resin, its preparation method, and its applications. The secondary cross-linked resin prepared by the present invention not only achieves cyano functionalization but also maintains a high specific surface area and forms a hierarchical pore structure dominated by micropores. The cyano-functionalized ultra-highly cross-linked polystyrene resin can selectively adsorb RDX from solution through electrostatic interactions and hydrogen bonding, exhibiting high adsorption capacity and rapid adsorption and removal effects, and has broad application prospects for treating explosive wastewater containing RDX.

[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of a cyano-functionalized hypercrosslinked polystyrene resin, characterized in that, The method comprises the following steps: 1) chloromethylated polystyrene resin is added into an organic solvent containing aromatic nitrile for swelling, and then an alkylating reaction is carried out under the action of a catalyst to obtain cyano-functionalized polystyrene resin; 2) the cyano-functionalized polystyrene resin is swelled in an organic solvent, and then a catalyst is added to obtain a mixture; 3) after the temperature of the mixture is raised to a target temperature, an organic solvent containing an external crosslinking agent is added into the mixture for crosslinking reaction to obtain cyano-functionalized hypercrosslinked polystyrene resin; The external crosslinking agent comprises one or more of dimethyl glycol formaldehyde, p-dichlorobenzyl and biphenyl dichlorobenzyl.

2. The method for preparing cyano-functionalized ultra-high crosslinked polystyrene resin according to claim 1, characterized in that, The aromatic nitrile is a cyano-containing aromatic compound; In step 1), the mass ratio of the aromatic nitrile to the chloromethylated polystyrene resin is 1:10-20, the volume-mass ratio of the organic solvent to the chloromethylated polystyrene resin is 10-40 mL:1 g, and the mass ratio of the catalyst to the chloromethylated polystyrene resin is 1:3-4.

3. The method of preparing a cyano-functionalized hypercrosslinked polystyrene resin according to claim 1 or 2, characterized in that, In step 1), the swelling time is 8-10 h, the temperature of the alkylating reaction is 45-85℃, and the time of the alkylating reaction is 8-18 h.

4. The method of preparing a cyano-functionalized hypercrosslinked polystyrene resin according to claim 1 or 2, characterized in that, In step 2), the volume-mass ratio of the organic solvent to the cyano-functionalized polystyrene resin is 10-20 mL:1 g, and the mass ratio of the catalyst to the cyano-functionalized polystyrene resin is 1:1-2.

5. The method for preparing cyano-functionalized ultra-high crosslinked polystyrene resin according to claim 4, characterized in that, In step 3), the target temperature is 45-85℃, and the time of the crosslinking reaction is 8-18 h.

6. The method of preparing a cyano-functionalized hypercrosslinked polystyrene resin according to claim 2 or 5, characterized in that, The mass ratio of the external crosslinking agent to the cyano-functionalized polystyrene resin is 0.3-1.5:1; In step 3), the mass-volume ratio of the external crosslinking agent to the organic solvent is 0.3-1.5 g:10-20 mL.

7. The method for preparing cyano-functionalized ultra-high crosslinked polystyrene resin according to claim 6, characterized in that, In steps 1) and 2), the catalyst independently comprises one or more of anhydrous ferric chloride, anhydrous aluminum chloride, anhydrous zinc chloride and anhydrous titanium chloride; In steps 1), 2) and 3), the organic solvent independently comprises one or more of dichloromethane, 1,2-dichloroethane, nitromethane, nitrobenzene and carbon disulfide.

8. The cyano-functionalized hypercrosslinked polystyrene resin prepared by the preparation method in any one of claims 1-7.

9. The cyano-functionalized hypercrosslinked polystyrene resin in claim 8 as an adsorbent for explosives wastewater.

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