Polyaniline graphene aerogel for catalytic degradation of new pollutants in water and preparation method thereof

Abstract

The application belongs to the technical field of carbon-based catalytic materials, and discloses a polyaniline graphene (PANI / RGO) aerogel for catalytic degradation of new pollutants in water and a preparation method T The original material of PANI / RGO is synthesized by using a freezing interfacial polymerization method; after washing, the PANI / RGO is uniformly dispersed in water through ultrasonic treatment; the dispersion liquid is subjected to hydrothermal synthesis of PANI / RGO aerogel and freeze-drying; and the target product PANI / RGO T The application has simple preparation operation, mild preparation conditions, and the prepared aerogel material has the hexagonal honeycomb crystal lattice layered structure of RGO and the high conductivity of PANI, enhances the effect of persulfate in generating active oxygen, can effectively degrade bisphenol A, realizes deep degradation of bisphenol A, can be recycled, is environmentally friendly, has no secondary pollution, does not need to consume extra energy, and has a wide practical application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of carbon-based catalytic materials, and in particular relates to a carbon-based catalytic material for catalytic degradation of new pollutants in water and a preparation method thereof. BACKGROUND

[0002] With the improvement of industrialization and urbanization, the types of pollutants in environmental water bodies become increasingly complex, and the new pollutants contained in various emerging pharmaceuticals and personal care products (PPCPs) are also increasing. However, the types of microorganisms capable of degrading such pollutants are few or have not yet been domesticated, so most of such pollutants are difficult to biodegrade. At the same time, the current conventional water treatment process has limited effect on the treatment of PPCPs, so there is an urgent need for a technology to effectively treat such pollutants.

[0003] The persulfate advanced oxidation technology is a technology that uses persulfate (such as potassium persulfate, sodium persulfate, etc.) as an oxidant to generate strong oxidizing free radicals (such as sulfate radicals, SO4 ·- ), thereby achieving efficient degradation and mineralization of organic pollutants. This technology is considered a good method for degrading PPCPs due to its high oxidation-reduction potential, long half-life, wider pH adaptation range, and better selectivity. Currently, the activation methods of persulfate advanced oxidation technology are mainly transition metal activation and external energy activation, which have the problems of high economic cost and easy secondary pollution. Graphene (GO) has good application prospects in the field of carbon-based catalysts due to its large specific surface area, high stability, and easy adjustment of surface chemical properties. However, pure graphene has catalytic inertness, which is not conducive to the catalysis of persulfate. Therefore, developing a modified catalyst with good PPCPs catalytic activity, environmental friendliness, and low cost is a current research hotspot. SUMMARY

[0004] The present application aims to solve the technical problems of secondary pollution and difficulty in secondary recycling of homogeneous catalysts in activating persulfate systems, and the problem of metal leakage of metal heterogeneous catalysts in activating persulfate systems, and proposes a metal-free immobilized heterogeneous carbon-based catalyst material and a preparation method thereof. The catalyst material has the advantages of large specific surface area, easy operation, and easy recycling.

[0005] In order to achieve the above technical purposes, the present application is realized by the following technical solutions:

[0006] According to one aspect of the present application, a polyaniline graphene aerogel for catalytic degradation of new pollutants in water is provided, which is obtained by the following preparation method:

[0007] (1) synthesizing PANI / RGO raw material by using a freeze interfacial polymerization method;

[0008] (2) after washing the PANI / RGO raw material obtained in step (1), uniformly dispersing it in water through ultrasonic treatment;

[0009] (3) synthesizing PANI / RGO aerogel through hydrothermal treatment of the dispersion obtained in step (2);

[0010] (4) freeze-drying the PANI / RGO aerogel obtained in step (3);

[0011] (5) modifying the PANI / RGO aerogel dried in step (4) at high temperature to obtain the target product PANI / RGO T .

[0012] According to another aspect of the present application, a preparation method of PANI / RGO aerogel for catalytic degradation of new pollutants in water is provided, characterized in that it comprises the following steps:

[0013] (1) synthesizing PANI / RGO raw material by using a freeze interfacial polymerization method;

[0014] (2) after washing the PANI / RGO raw material obtained in step (1), uniformly dispersing it in water through ultrasonic treatment;

[0015] (3) synthesizing PANI / RGO aerogel through hydrothermal treatment of the dispersion obtained in step (2);

[0016] (4) freeze-drying the PANI / RGO aerogel obtained in step (3);

[0017] (5) modifying the PANI / RGO aerogel dried in step (4) at high temperature to obtain the target product PANI / RGO T .

[0018] In the above-mentioned PANI / RGO aerogel for catalytic degradation of new pollutants in water and the preparation method thereof:

[0019] Further, the freeze interfacial polymerization method of step (1) comprises: placing an ammonium persulfate hydrochloride solution in a -25--18℃ ethanol temperature-controlled water bath, adding a GO dispersion solution dissolved through ultrasonic treatment after complete freezing, adding a pre-cooled aniline hydrochloride solution after complete freezing, and reacting for 9-12h at 0-2℃.

[0020] In step (1), preferably, the mass ratio of aniline to GO is 1:1-1:4.

[0021] In step (1), preferably, the molar ratio of aniline to ammonium persulfate is 1:0.5-1:2.

[0022] In step (1), preferably, the concentration of mixed hydrochloric acid is 0.5-2 mol·L -1 .

[0023] Further, the ultrasonic time in step (2) is 30-45 min.

[0024] Further, the hydrothermal synthesis in step (3) is to place the dispersion liquid obtained in step (2) in a hydrothermal kettle, and react at 170-190 DEG C for 9-12 h.

[0025] Further, the freeze-drying time in step (4) is 12-24 h.

[0026] Further, the high-temperature modification of step (5) includes: placing the PANI / RGO aerogel obtained in step (4) into a tube furnace, introducing nitrogen to remove oxygen, then heating to 900-1000 DEG C, and maintaining at the temperature for 1-2 h, then cooling to room temperature to obtain the target product PANI / RGO T .

[0027] The beneficial effects of the present application are:

[0028] The present application uses aniline, graphene and ammonium persulfate as raw materials, and sequentially uses freeze interface polymerization, hydrothermal synthesis and high-temperature thermal reduction to prepare a carbon-based catalyst, and the prepared catalytic material has high activity:

[0029] (1) The carbon-based catalyst PANI / RGO T aerogel prepared by the present application combines PANI and RGO prepared by the freeze interface polymerization method to generate aerogel, and has the hexagonal honeycomb lattice structure of RGO and the high conductivity of PANI, and the operation is simple and the preparation conditions are mild;

[0030] (2) The carbon-based catalyst PANI / RGO T aerogel prepared by the present application uses PANI with high conductivity to enhance the effect of generating active oxygen by persulfate;

[0031] (3) The carbon-based catalyst PANI / RGO T aerogel prepared by the present application can effectively degrade bisphenol A and realize deep degradation of bisphenol A;

[0032] (4) The carbon-based catalyst PANI / RGO T aerogel prepared by the present application can be recycled and is environmentally friendly without secondary pollution;

[0033] (V) The carbon-based catalyst PANI / RGO prepared in this invention T Aerogels do not require additional energy, such as ultrasound, light, or electricity, which reduces costs and has broad prospects for practical applications.

[0034] In summary, the carbon-based catalyst PANI / RGO of the present invention T Aerogel and its preparation method are presented. The preparation method is simple and reduces energy consumption. The prepared catalyst further improves the effect of persulfate in generating active oxygen, and the degradation rate of bisphenol A can reach 88% in 60 minutes. Attached Figure Description

[0035] Figure 1 PANI / RGO of the present invention T Flowchart of aerogel catalytic material preparation;

[0036] Figure 2 PANI / RGO prepared in Example 1 T Images of aerogel catalytic materials;

[0037] Figure 3 PANI / RGO prepared for different hydrochloric acid concentrations in Example 2 T Electrical conductivity diagram of aerogel catalytic materials;

[0038] Figure 4 PANI / RGO prepared for different hydrochloric acid concentrations in Example 2 T Fourier transform infrared (FTIR) images of aerogel catalytic materials;

[0039] Figure 5 PANI / RGO prepared at different mass ratios as in Example 3 T Graph showing the effect of aerogel catalytic material in degrading bisphenol A;

[0040] Figure 6 PANI / RGO prepared at different thermal reduction temperatures in Example 4 T Graph showing the effect of aerogel catalytic material in degrading bisphenol A;

[0041] Figure 7 PANI / RGO prepared in Example 4 T A graph showing the degradation effect of aerogel catalytic materials on tap water containing bisphenol A. Detailed Implementation

[0042] like Figure 1 As shown, this invention provides a polyaniline-graphene aerogel for catalytic degradation of new pollutants in water and its preparation method, which is prepared according to the following steps:

[0043] (1) PANI / RGO raw materials were synthesized by cryo-interface polymerization at a reaction temperature of 0-2℃.

[0044] In some preferred embodiments of the present invention, the hydrochloric acid solution of ammonium persulfate is placed in an ethanol temperature-controlled water bath at -25 to -18°C, and after complete freezing, a GO dispersion dissolved by ultrasound is added. After complete freezing, a hydrochloric acid solution containing aniline that has been pre-cooled is added, and the reaction time is 9-12 hours.

[0045] More preferably, the mass ratio of aniline to GO is 1:1-1:4; the molar ratio of aniline to ammonium persulfate is 1:0.5-1:2; and the concentration of the mixed hydrochloric acid is 0.5-2 mol·L⁻¹. -1 .

[0046] (2) After washing the PANI / RGO raw material obtained in step (1), it is ultrasonically dispersed evenly in water.

[0047] In some preferred embodiments of the present invention, the ultrasound duration is 30-45 minutes.

[0048] (3) The dispersion obtained in step (2) was hydrothermally synthesized into PANI / RGO aerogel at a reaction temperature of 170-190℃.

[0049] In some preferred embodiments of the present invention, hydrothermal synthesis involves placing the dispersion obtained in step (2) in a hydrothermal reactor and reacting it at 170-190°C for 9-12 hours.

[0050] (4) The PANI / RGO aerogel obtained in step (3) is freeze-dried.

[0051] In some preferred embodiments of the present invention, the freeze-drying time is 12-24 hours.

[0052] (5) The PANI / RGO aerogel dried in step (4) is subjected to high-temperature modification at 900-1000℃ to obtain the target product PANI / RGO. T .

[0053] In some preferred embodiments of the present invention, the PANI / RGO aerogel obtained in step (4) is placed in a tube furnace, nitrogen is introduced to remove oxygen, then heated to 900-1000°C and maintained at that temperature for 1-2 hours, and then cooled to room temperature to obtain the target product PANI / RGO. T Finally, remove the materials and store them in a desiccator.

[0054] In a preferred embodiment of the present invention, the catalytic performance of the material as a catalyst is demonstrated.

[0055] The present invention will be further described in detail below through specific embodiments. These embodiments will enable those skilled in the art to have a more comprehensive understanding of the present invention, but will not limit the present invention in any way.

[0056] Example 1

[0057] A method for preparing a polyaniline-graphene aerogel catalytic material, the specific steps of which are as follows:

[0058] To prepare highly conductive nitrogen-doped graphene, a cryo-interfacial polymerization method was used to generate PANI in situ on the surface of graphene oxide. First, a certain mass of aniline (AN) and ammonium persulfate were dissolved separately in 10 mL of hydrochloric acid (1 mol·L⁻¹). -1 The aniline solution was ultrasonically mixed to obtain solutions of a certain concentration, denoted as solution A and solution B, respectively. The aniline solution was then pre-cooled in a 4°C refrigerator. Simultaneously, ammonium persulfate solution was poured into a 100mL (40mm inner diameter) double-walled screw-top bottle and placed in an ethanol-controlled water bath at -18°C. After solution B was completely frozen, 20mL of a solution containing 0.2g of graphene oxide was added to solution B, and the mixture was kept in a -18°C water bath until completely frozen before adding the pre-cooled solution A. The water bath temperature was then adjusted to 2°C and the reaction continued for 12 hours. After the reaction, the solution was washed with ethanol and deionized water until the color no longer changed. The resulting solid was then ultrasonically dispersed in 20mL of ultrapure water and placed in a 20mL reaction vessel at 180°C for 12 hours. After cooling, the solution was washed with ultrapure water for 5-6 hours, pre-cooled, and then freeze-dried at -80°C for 24 hours.

[0059] The freeze-dried material was placed in a tube furnace for thermal reduction, initially at 1 L·min. -1 At a flow rate of [flow rate], nitrogen gas was introduced for 10 min to remove oxygen. Then, nitrogen gas was introduced from room temperature at a flow rate of 10 °C / min. -1 The temperature was heated to a certain temperature at a certain heating rate and maintained at that temperature for 1 hour, then increased at a rate of 5℃·min. -1 After annealing at 300℃, the material is allowed to cool naturally to room temperature. Once cooling is complete, the resulting material is PANI / RGO. T Aerogels should be stored in a desiccator away from light.

[0060] Figure 2 To obtain PANI / RGO T The image of the aerogel shows that the material is approximately cylindrical, with a diameter of about 2 cm and a height of about 3.5 cm.

[0061] Example 2

[0062] Following the method of Example 1, the hydrochloric acid concentration of both solution A and solution B was 0 mol·L⁻¹. -1 0.25 mol·L -10.5 mol·L -1 1 mol·L -1 1.5 mol·L -1 2 mol·L -1 PANI / RGO were prepared separately T Aerogel catalytic materials were used to prepare PANI / RGO with different hydrochloric acid concentrations. T The electrical conductivity of aerogel catalytic materials is as follows: Figure 3 As shown, PANI / RGO prepared with different hydrochloric acid concentrations T Fourier transform infrared spectral images of aerogel catalytic materials, such as Figure 4 As shown.

[0063] from Figure 3 It can be seen that under a pressure of 1 MPa, the concentration of hydrochloric acid is 0-2 mol·L⁻¹. -1 Within a certain range, the conductivity first increases and then decreases with increasing hydrochloric acid concentration, reaching a certain level at 1 mol·L⁻¹. -1 The conductivity is highest at that time. From Figure 4 It can be seen from this that 1590cm -1 The peak value at 1490 cm⁻¹ represents the absorption vibration of the quinone backbone N=Q=N of the polyaniline molecular chain. -1 The peak at 1290 cm⁻¹ corresponds to the absorption vibration of the benzene-structured NBN. -1 The peak at 1170 cm⁻¹ is caused by the stretching vibration of CN in aromatic amines. -1 and 810cm -1 The peak at 810 cm⁻¹ represents the in-plane and out-of-plane bending vibrations of the benzene ring. -1 The presence of only one peak indicates that aniline undergoes para-polymerization. (0.5-2 mol·L⁻¹) -1 The peak intensities of polyaniline prepared by the hydrochloric acid solution system were all higher than those of 0 mol·L⁻¹. -1 With 0.25 mol·L -1 It has improved over time, especially at 1590cm. -1 and 1490cm -1 The peak at this location indicates a significant enhancement of the polyaniline molecular chain, suggesting an increased degree of polymerization. It is evident that hydrochloric acid helps improve the conductivity of polyaniline, but excessively high hydrochloric acid concentrations can inhibit aniline polymerization. The concentration range is 0.5-2 mol·L⁻¹. -1 Polyaniline prepared under hydrochloric acid concentration showed better conductivity. Considering both the degree of polymerization and the amount of hydrochloric acid used, 0.5 mol·L⁻¹ was the optimal concentration. -1 Hydrochloric acid is the optimal choice for the preparation of polyaniline.

[0064] Example 3

[0065] Following the method of Example 1, while maintaining PANI / RGO TDuring the aerogel preparation process, while keeping the mass of graphene constant, the mass ratio of aniline to graphene was changed by altering the mass of aniline. PANI / RGO was prepared with aniline to graphene mass ratios of 1:1, 1:2, 1:4, and 1:8, respectively. T Aerogel catalytic materials.

[0066] Using bisphenol A as a typical new pollutant, the resulting PANI / RGO ratios with different aniline-to-graphene mass ratios were analyzed. T The effect of the mass ratio of aniline to graphene on the degradation effect was investigated by using aerogel catalytic materials to degrade bisphenol A under the same conditions.

[0067] Add 100 mL of serum containing 5 mmol·L⁻¹ to a brown serum bottle. -1 10 mg / L of phosphate-buffered saline (PBS) at pH 7 -1 The bisphenol A solution was placed in a constant temperature shaker, with the temperature controlled at 25-30℃ and the shaking speed at 250 rpm·min. -1 Take 0.8 mL of the initial sample, filter it through a 0.22 μm PTFE syringe filter, and place it in a 1.5 mL chromatographic vial for instrument analysis; then add 0.01 g of catalyst ([PANI / RGO)). T ] = 0.1 g·L -1 Start the pollutant adsorption experiment, taking a sample every five minutes, 0.8 mL each time, for four times. After each sample, filter it through a 0.22 μm PTFE syringe filter and place it in a 1.5 mL chromatographic vial for instrument analysis. After adsorption equilibrium is reached, add 1.96 mL of 50 mmol·L⁻¹ solution. -1 PDS ([PDS] = 1 mmol·L) -1 To initiate the catalytic reaction, samples were taken at 1, 2.5, 5, 10, 15, 20, 30, and 60 minutes, with 0.8 mL taken each time. After sampling, the samples were filtered through a 0.22 μm PTFE needle filter and placed into a 1.5 mL chromatographic vial for instrument analysis.

[0068] Figure 5 Showing PANI / RGO at different mass ratios T The effectiveness of aerogel in catalytic degradation of bisphenol A increases with the increase of the mass ratio of aniline to graphene, resulting in a higher PANI / RGO ratio. T The adsorption and removal rate of bisphenol A by aerogels did not vary significantly, but the highest adsorption and removal rate (8.83%) was observed at a mass ratio of 1:2. The degradation efficiency generally showed a trend of first increasing and then decreasing, with better performance at mass ratios of 1:1 to 1:4, and the highest efficiency at 1:2, reaching 61.46% after 60 minutes.

[0069] Example 4

[0070] Following the method in Example 1, PANI / RGO was prepared at thermal reduction temperatures of 600℃, 700℃, 800℃, 900℃, and 1000℃, respectively. T Aerogel catalytic materials. Using bisphenol A as a typical novel pollutant, PANI / RGO was prepared at different thermal reduction temperatures. T The effect of thermal reduction temperature on the degradation efficiency was investigated by using aerogel catalytic materials to degrade bisphenol A under the same conditions.

[0071] Add 100 mL of serum containing 5 mmol·L⁻¹ to a brown serum bottle. -1 10 mg / L of PBS -1 The bisphenol A solution was placed in a constant temperature shaker, with the temperature controlled at 25-30℃ and the shaking speed at 250 rpm·min. -1 Take 0.8 mL of the initial sample, filter it through a 0.22 μm PTFE syringe filter, and place it in a 1.5 mL chromatographic vial for instrument analysis; then add 0.01 g of catalyst ([PANI / RGO)). T ] = 0.1 g·L -1 Start the pollutant adsorption experiment, taking a sample every five minutes, 0.8 mL each time, for four times. After each sample, filter it through a 0.22 μm PTFE syringe filter and place it in a 1.5 mL chromatographic vial for instrument analysis. After adsorption equilibrium is reached, add 1.96 mL of 50 mmol·L⁻¹ solution. -1 PDS ([PDS] = 1 mmol·L) -1 To initiate the catalytic reaction, samples were taken at 1, 2.5, 5, 10, 15, 20, 30, and 60 minutes, with 0.8 mL taken each time. After sampling, the samples were filtered through a 0.22 μm PTFE needle filter and placed into a 1.5 mL chromatographic vial for instrument analysis.

[0072] Figure 6 This shows that as the thermal reduction temperature increases, PANI / RGO... T The adsorption and removal rate and degradation efficiency of aerogels for bisphenol A generally showed an increasing trend, with better degradation effects at 900℃ and 1000℃. Specifically, the adsorption and removal rate was 11.23% at 900℃, and the degradation efficiency reached 76.27% after 60 minutes.

[0073] The PANI / RGO prepared at 900°C in Example 4 T An experiment using an aerogel catalyst to degrade tap water containing bisphenol A was conducted, with the addition of 1 mmol·L⁻¹. -1 Using potassium persulfate (PDS) as an oxidant, and bisphenol A (BPA) as a typical novel pollutant, dissolved in tap water, the PANI / RGO ratio was investigated. T / The degradation effect of PDS catalytic system on bisphenol A in tap water.

[0074] Add 100 mL of serum containing 5 mmol·L⁻¹ to a brown serum bottle. -1 10 mg / L of PBS -1 A bisphenol A aqueous solution was placed in a constant-temperature shaker, with the temperature controlled at 25-30℃ and the shaking speed at 250 rpm·min. -1 Take 0.8 mL of the initial sample, filter it through a 0.22 μm PTFE syringe filter, and place it in a 1.5 mL chromatographic vial for instrument analysis; then add 0.01 g of catalyst ([PANI / RGO)). T ] = 0.1 g·L -1 Start the pollutant adsorption experiment, taking a sample every five minutes, 0.8 mL each time, for four times. After each sample, filter it through a 0.22 μm PTFE syringe filter and place it in a 1.5 mL chromatographic vial for instrument analysis. After adsorption equilibrium is reached, add 1.96 mL of 50 mmol·L⁻¹ solution. -1 PDS ([PDS] = 1 mmol·L) -1 The catalytic reaction was initiated, and samples were taken at 1, 2.5, 5, 10, 15, 20, 30, and 60 minutes, with 0.8 mL taken each time. After collection, the samples were filtered through a 0.22 μm PTFE syringe filter and then placed into 1.5 mL chromatographic vials for instrument analysis. The results are attached. Figure 7 As shown, PANI / RGO T The aerogel achieved an adsorption removal rate of 14.34% for bisphenol A and a degradation efficiency of 88% within 60 minutes, effectively removing bisphenol A from tap water.

[0075] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A polyaniline-graphene aerogel for catalytic degradation of new pollutants in water, characterized in that, It is obtained by the following preparation method: (1) PANI / RGO raw materials were synthesized by cryo-interfacial polymerization. The cryo-interfacial polymerization method included: placing an ammonium persulfate hydrochloric acid solution in an ethanol-controlled water bath at -25 to -18 ℃, and after complete freezing, adding an ultrasonically dissolved GO dispersion, and after complete freezing, adding a pre-cooled aniline-containing hydrochloric acid solution, and reacting at 0 to 2 ℃ for 9 to 12 h; wherein the mass ratio of aniline to GO was 1:1 to 1:4; the molar ratio of aniline to ammonium persulfate was 1:0.5 to 1:2; and the concentration of the hydrochloric acid after mixing was 0.5 to 2 mol·L⁻¹. −1 ; (2) After washing the PANI / RGO raw material obtained in step (1), it is ultrasonically dispersed evenly in water; (3) The dispersion obtained in step (2) is used to synthesize PANI / RGO aerogel by hydrothermal reaction; the hydrothermal reaction is to place the dispersion obtained in step (2) in a hydrothermal reactor and react at 170-190℃ for 9-12 h. (4) Freeze-dry the PANI / RGO aerogel obtained in step (3); (5) The PANI / RGO aerogel dried in step (4) is subjected to high-temperature modification to obtain the target product PANI / RGO. T The high-temperature modification includes: placing the PANI / RGO aerogel obtained in step (4) into a tube furnace, introducing nitrogen to remove oxygen, then heating to 900-1000 ℃ and maintaining at that temperature for 1-2 h, and then cooling to room temperature.

2. The polyaniline-graphene aerogel for catalytic degradation of new pollutants in water according to claim 1, characterized in that, The ultrasound time in step (2) is 30-45 min.

3. The polyaniline-graphene aerogel for catalytic degradation of new pollutants in water according to claim 1, characterized in that, The freeze-drying time in step (4) is 12-24 h.

4. A method for preparing a polyaniline graphene aerogel for catalytic degradation of new pollutants in water as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) PANI / RGO raw materials were synthesized by cryo-interfacial polymerization; (2) After washing the PANI / RGO raw material obtained in step (1), it is ultrasonically dispersed evenly in water; (3) The dispersion obtained in step (2) was hydrothermally synthesized into PANI / RGO aerogel; (4) Freeze-dry the PANI / RGO aerogel obtained in step (3); (5) The PANI / RGO aerogel dried in step (4) is subjected to high-temperature modification to obtain the target product PANI / RGO. T .

Images