Preparation Method and Application of a Conductive Polymer-Cellulose Composite Material

Abstract

The present application relates to the technical field of soil remediation materials, and more specifically, to a method for preparing and applying a conductive polymer-cellulose composite material. The composite material uses activated carbon fiber as a raw material to prepare a modified cellulose material. A conductive polymer, namely phytic acid-doped polyaniline, is prepared by polymerization and composited with the modified cellulose material to prepare a conductive polymer-cellulose composite material. The conductive polymer-cellulose composite material is combined with electric remediation technology to remediate cadmium-contaminated soil. Applying the conductive polymer-cellulose composite material to electric remediation technology improves the remediation capacity of heavy metal-contaminated soil.

Description

Technical Field

[0001] The present application relates to the technical field of soil remediation materials, and more specifically, to a preparation method and application of a conductive polymer-cellulose composite material. Background Art

[0002] Among the soils identified as contaminated, metal and metalloid pollutants accounted for 82.4%, with the main heavy metal pollutants being cadmium (Cd), nickel (Ni), and copper (Cu).

[0003] Conductive polymers are a type of high molecular weight polymer with conjugated π bonds that can be transformed from insulators into conductors or semiconductors after being "doped". Conductive polymers and their composites can be used as adsorbents to absorb dyes and heavy metals.

[0004] Activated carbon fiber is a new generation of multifunctional adsorption materials. Its rich pore structure allows it to be formed into a variety of shapes depending on the environment in which it is used. Activated carbon fiber is primarily used in forms such as felt, cloth, paper, and honeycomb. It exhibits excellent adsorption and desorption properties and can be reused multiple times without causing secondary pollution. Due to its excellent adsorption properties, activated carbon fiber has gained widespread application in recent years, offering unique advantages in air pollution control, wastewater treatment, and soil remediation.

[0005] Electrodynamic remediation, as an in-situ remediation method, involves placing electrodes in the soil and applying a low, mild DC voltage. The voltage gradient created between the electrodes causes heavy metals and other contaminants to be desorbed from the soil and concentrated around the electrodes, thereby removing heavy metal contamination. This method is gaining increasing attention due to its minimal soil damage, suitability for low-permeability soils, and high pollutant removal efficiency.

[0006] Electric remediation has the advantages of minimal equipment, ease of operation, no soil disturbance, and in-situ remediation; however, it has the disadvantage of low efficiency. Adsorption, on the other hand, offers advantages such as ease of operation, high efficiency, and the ability to separate heavy metal ions from the soil. However, the addition of adsorbents to the soil reduces its electrical conductivity, thereby reducing remediation efficiency. Therefore, enhancing the conductivity of adsorbents is an urgent issue that needs to be addressed. Summary of the Invention

[0007] The present disclosure provides a preparation method and application of a conductive polymer-cellulose composite material, and applies the conductive polymer-cellulose composite material to electric remediation technology to improve the remediation ability of heavy metal-contaminated soil.

[0008] In a first aspect, the present disclosure provides a method for preparing a conductive polymer-cellulose composite material, wherein the composite material uses activated carbon fiber as raw material to prepare a modified cellulose material; a conductive polymer, namely phytic acid-doped polyaniline, is prepared by a polymerization method and compounded with the modified cellulose material to prepare a conductive polymer-cellulose composite material, and the conductive polymer-cellulose composite material is combined with electric remediation technology to be used for remediating cadmium-contaminated soil.

[0009] Through two-step composite modification of NaOH and high temperature, the modified activated carbon fiber ACF material was finally obtained, and a conductive polymer-cellulose composite material was prepared.

[0010] Preferably, the method comprises the following steps:

[0011] S1: Preparation of modified cellulose: small pieces of activated carbon fiber (ACF) were boiled and stirred in water, then immersed in a NaOH solution and placed in a tubular heating furnace and heated under N2 gas protection to obtain ACF-Na-HT;

[0012] S2: Preparation of a conductive polymer: Aniline and concentrated hydrochloric acid were added to deionized water, and the mixture was ultrasonicated for 10 to 30 minutes and then stirred. A phytic acid solution was then added and ultrasonicated for 10 to 30 minutes to prepare a mixed solution. The mixed solution was then placed in an ice water bath and stirred, and then an ammonium persulfate (APS) solution was slowly added dropwise to prepare a conductive polymer solution.

[0013] S3: Preparation of conductive polymer-cellulose: ACF-NA-HT was added to the conductive polymer solution prepared in step S2, and the mixture was kept in an ice bath for 3 to 6 hours. The reaction solution was then filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate was neutral. The product was dried in an oven at 60 to 90°C for 12 to 24 hours to obtain a conductive polymer-cellulose, which was designated as P-PANI / ACF.

[0014] Preferably, the method for preparing the modified cellulose in S1 comprises the following steps:

[0015] (1) Cut the activated carbon fiber (ACF) into small pieces and boil and stir in water for 1-2 h. Then rinse the ACF surface with deionized water until the filtrate is neutral. Dry the ACF in an oven at 120-150°C for 6-24 h. Take out and seal the ACF for dry storage. This is recorded as ACF-0.

[0016] (2) Weigh 1g-5g of ACF-0 and soak it in 100ml-200ml of NaOH solution, shake it at a constant temperature of 60-90℃ for 1-3h, rinse it with deionized water until the filtrate is neutral, and dry it in an oven at 120-150℃ for 6-24h. This is recorded as ACF-Na.

[0017] (3) Place ACF-Na in a tubular heating furnace and heat to 600-900°C at 10°C / min under N2 protection. Keep warm for 1-2 hours, then air-cool. Remove and seal the sample for dry storage. This is referred to as ACF-Na-HT.

[0018] Preferably, in step S2, the mass ratio of aniline to phytic acid is 3:1; and the molar ratio of aniline to APS is 1:1.

[0019] Preferably, the mass ratio of aniline to ACF-Na-HT in step S2 and step S3 is 1:1-10.

[0020] Preferably, the concentration of the NaOH solution in step (2) is 1-8 mol / L.

[0021] In a second aspect, the present disclosure provides an application of a conductive polymer-cellulose composite material, and a specific application method is as follows:

[0022] A: The device consists of a cathode chamber, an anode chamber, a soil chamber, and a DC power supply. The device is circular and made of acrylic, 10 cm high and 20 cm in diameter. The cathode chamber in the middle consists of two cylindrical hollow structures, one inside and one outside. The cathode and the other outside are made of graphite and stainless steel, respectively. The electrodes are cylindrical, 1 cm in diameter, and arranged in a regular hexagonal pattern. The distance between the cathode and the anode is 8 cm. The entire device also requires a porous separator, non-woven filter cloth, a peristaltic pump, and copper wire.

[0023] B: After weighing 60 mg / kg cadmium-contaminated soil, distilled water was used as the soil saturation solution, stirred evenly, and after standing for 24 hours, the soil was saturated by the force and added to the soil sample chamber for compaction. To prevent the soil from entering the cathode chamber, non-woven cotton was arranged on the inner wall of the cathode chamber cylinder, and the ACF-0, ACF-Na-HT, and P-PANI / ACF were respectively filled in the cathode chamber cylinder to keep their height consistent with the height of the soil;

[0024] C: The electric field strength was set to 2 V / cm, the power was applied for 120 h, 0.1 mol / L citric acid was used as the electrolyte in the cathode chamber, and a peristaltic pump was used to circulate the electrolyte. The current changes were measured and recorded at intervals.

[0025] D: The electrokinetic remediation experiment without adding adsorbent was recorded as EKR-1, and the electrokinetic-adsorption combined remediation experiments with adding adsorbents ACF-0, ACF-Na-HT, and P-PANI / ACF were recorded as EKR-2, EKR-3, and EKR-4, respectively.

[0026] Using a hexagonal multi-anode electroremediation experimental setup, an adsorption zone was set up on the outer ring of the cathode and adsorbent was added. The uniform, narrow, and shallow micropores on the surface of the activated carbon fibers allow for rapid adsorption of heavy metal cadmium ions through a pore-filling mechanism. Cadmium cations strongly interact with oxygen-containing functional groups through a cation-ion-electron sharing mechanism. The modified activated carbon fibers contain abundant metal ion adsorption sites, effectively increasing the adsorption of cadmium cations.

[0027] Preferably, the pH of the soil saturated solution in step B is 6.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. In this application, a modified activated carbon fiber ACF material is finally obtained by a two-step composite modification of NaOH and high temperature, and a conductive polymer-cellulose composite material is prepared;

[0030] 2. This application applies conductive polymer-cellulose composite materials to electrokinetic remediation technology to improve the remediation capacity of heavy metal-contaminated soil;

[0031] 3. This application uses a regular hexagonal multi-anode electric remediation experimental device, with an adsorption zone set up on the outer ring of the cathode and an adsorbent added. The uniform, narrow, and shallow micropores on the surface of the activated carbon fiber can rapidly adsorb heavy metal cadmium ions through a pore-filling mechanism. Cadmium cations strongly interact with oxygen-containing functional groups through a cation-ion-electron sharing mechanism. The modified activated carbon fibers contain abundant metal ion adsorption sites, which can effectively adsorb more cadmium cations.

[0032] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the scope of protection of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 1 is a scanning electron microscope (SEM) image of the adsorbent prepared in Examples 1 to 3 of the present invention and Comparative Examples 2 to 3;

[0034] Figure 2 1 is the X-ray diffraction (XRD) pattern of the adsorbents prepared in Examples 1 to 3 of the present invention and Comparative Examples 2 to 3;

[0035] Figure 3 This is a diagram showing the adsorption effect of the composite materials prepared in Examples 1 to 3 of the present invention on cadmium;

[0036] Figure 4 This is a graph showing the removal rate of heavy metal cadmium at each sampling point using the adsorbent prepared in Comparative Examples 1 to 3 in the electrokinetic-adsorption combined remediation process;

[0037] Figure 5 Schematic diagram of the application device structure and sampling point distribution: (a) structural diagram, (b) sampling point distribution diagram. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0039] Example

[0040] Example 1

[0041] A method for preparing a conductive polymer-cellulose composite material comprises the following steps:

[0042] (1) Preparation of modified cellulose: In order to remove impurities from activated carbon fibers, small pieces of activated carbon fibers cut into 1.5 cm long were placed in water and boiled with stirring for 1 hour. The surface of the activated carbon fibers was then rinsed with deionized water until the filtrate was neutral. The fibers were placed in an oven and dried at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-0. 1 g of ACF-0 was weighed and soaked in 100 ml of 1 mol / L NaOH solution and oscillated at 60°C for 3 hours. The fibers were rinsed with deionized water until the filtrate was neutral, and dried in an oven at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na. The ACF-Na was then placed in a tubular heating furnace and heated to 600°C at 10°C / min under N2 protection. After keeping the temperature for 2 hours, the fibers were cooled to below 200°C and then air-cooled. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na-HT.

[0043] (2) Preparation of conductive polymer: Add 20 ml of deionized water to a 50 ml beaker, then add 1 ml of aniline and concentrated hydrochloric acid, ultrasonicate for 10 minutes and stir, then add phytic acid solution (the mass ratio of phytic acid to aniline is 1:3) and ultrasonicate for 20 minutes. Then place the beaker in an ice water bath and stir, then slowly add ammonium persulfate solution (the molar ratio of aniline to ammonium persulfate is 1:1). Recorded as P-PANI

[0044] (3) Preparation of composite materials: After all the ammonium persulfate solution was added, ACF-NA-HT was added to the mixture. The addition ratio of aniline monomer to activated carbon fiber ACF-NA-HT was 1:3, and the mixture was completely immersed in the mixture. The mixture was kept in an ice bath for 3 h. The reaction mixture was filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate was neutral. A dark green product, phytic acid-doped polyaniline / activated carbon fiber composite material, was obtained, which was denoted as P-PANI / ACF. The product was placed in a 60°C oven and dried for 24 h.

[0045] Example 2

[0046] A method for preparing a conductive polymer-cellulose composite material comprises the following steps:

[0047] (1) Preparation of modified cellulose: In order to remove impurities from activated carbon fibers, small pieces of activated carbon fibers cut into 1.5 cm long were placed in water and boiled with stirring for 1 hour. The surface of the activated carbon fibers was then rinsed with deionized water until the filtrate was neutral. The fibers were placed in an oven and dried at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-0. 1 g of ACF-0 was weighed and soaked in 100 ml of 1 mol / L NaOH solution and oscillated at 60°C for 3 hours. The fibers were rinsed with deionized water until the filtrate was neutral, and dried in an oven at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na. The ACF-Na was then placed in a tubular heating furnace and heated to 600°C at 10°C / min under N2 protection. After keeping the temperature for 2 hours, the fibers were cooled to below 200°C and then air-cooled. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na-HT.

[0048] (2) Preparation of conductive polymer: Add 20 ml of deionized water to a 50 ml beaker, then add 1 ml of aniline and concentrated hydrochloric acid, ultrasonicate for 10 minutes and stir, then add phytic acid solution (the mass ratio of phytic acid to aniline is 1:3) and ultrasonicate for 20 minutes. Then place the beaker in an ice water bath and stir, then slowly add ammonium persulfate solution (the molar ratio of aniline to ammonium persulfate is 1:1). Recorded as P-PANI

[0049] (3) Preparation of composite materials: After all the ammonium persulfate solution was added, ACF-NA-HT was added to the mixture. The addition ratio of aniline monomer to activated carbon fiber ACF-NA-HT was 1:5, and the mixture was completely immersed in the mixture. The mixture was kept in an ice bath for 3 h. The reaction mixture was filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate was neutral. A dark green product, phytic acid-doped polyaniline / activated carbon fiber composite material, was obtained, which was recorded as P-PANI / ACF. The product was placed in a 60°C oven and dried for 24 h.

[0050] Example 3

[0051] A method for preparing a conductive polymer-cellulose composite material comprises the following steps:

[0052] (1) Preparation of modified cellulose: In order to remove impurities from activated carbon fibers, small pieces of activated carbon fibers cut into 1.5 cm long were placed in water and boiled with stirring for 1 hour. The surface of the activated carbon fibers was then rinsed with deionized water until the filtrate was neutral. The fibers were placed in an oven and dried at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-0. 1 g of ACF-0 was weighed and soaked in 100 ml of 1 mol / L NaOH solution and oscillated at 60°C for 3 hours. The fibers were rinsed with deionized water until the filtrate was neutral, and dried in an oven at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na. The ACF-Na was then placed in a tubular heating furnace and heated to 600°C at 10°C / min under N2 protection. After keeping the temperature for 2 hours, the fibers were cooled to below 200°C and then air-cooled. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na-HT.

[0053] (2) Preparation of conductive polymer: Add 20 ml of deionized water to a 50 ml beaker, then add 1 ml of aniline and concentrated hydrochloric acid, ultrasonicate for 10 minutes and stir, then add phytic acid solution (the mass ratio of phytic acid to aniline is 1:3) and ultrasonicate for 20 minutes. Then place the beaker in an ice water bath and stir, then slowly add ammonium persulfate solution (the molar ratio of aniline to ammonium persulfate is 1:1). Recorded as P-PANI

[0054] (3) Preparation of composite materials: After all the ammonium persulfate solution was added, ACF-NA-HT was added to the mixture. The addition ratio of aniline monomer to activated carbon fiber ACF-NA-HT was 1:10, and the mixture was completely immersed in the mixture. The mixture was kept in an ice bath for 3 h. The reaction mixture was filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate was neutral. A dark green product, phytic acid-doped polyaniline / activated carbon fiber composite material, was obtained, which was recorded as P-PANI / ACF. The product was placed in a 60°C oven and dried for 24 h.

[0055] Performance determination of composite materials:

[0056] The surface morphology of ACF and PANI before and after composite was analyzed using a JEM-2100 high-resolution transmission electron microscope (manufactured by JEOL Ltd.). The surface functional groups of ACF and PANI before and after composite were tested using a Nicoleti S50 Fourier transform infrared spectrometer (Thermofisher, USA). The ACF and PANI before and after composite were characterized using a D / MAX2500 X-ray powder diffractometer (manufactured by Rigaku Corporation, Japan). The X-ray diffraction patterns are shown in Figure 2. Figure 2As shown, typical polyaniline reflections are shown at 2θ = 14.6°, 20.1° and 25.5°, corresponding to the (011), (020) and (200) crystal planes of PANI, respectively. The diffraction peaks appearing at 2θ = 20.1° and 25.5° indicate that the long polyaniline chains maintain parallel and perpendicular periodicity. Compared with the spectrum of ACF-NA-HT, the diffraction peak near 2θ = 25.6° of P-PANI / ACF is significantly increased, which means that P-PANI has the characteristics of changing the crystal morphology of ACF-Na-HT. In addition, no diffraction peaks are observed near 2θ = 20.1° and 25.5°, which means that the characteristic peaks of the graphitized structure may be covered by P-PANI, but the functional modification process of P-PANI / ACF does not affect the structure of the substrate, and P-PANI / ACF has the structural characteristics and skeleton of polyaniline and activated carbon fiber.

[0057] Comparative Example

[0058] Comparative Example 1

[0059] A composite material was prepared according to the method of Example 2, except that to remove impurities from the activated carbon fibers, small pieces of activated carbon fibers (ACF) cut into 1.5 cm squares were placed in boiling water with stirring for 1 hour. The ACF surface was then rinsed with deionized water until the filtrate was neutral. The resulting mixture was then dried in an oven at 120°C for 12 hours. The mixture was then sealed and stored dry, designated ACF-0.

[0060] Comparative Example 2

[0061] The composite material was prepared according to the method of Example 2, except that the modified cellulose was prepared as follows: In order to remove impurities from the activated carbon fiber, small pieces of activated carbon fiber cut into 1.5 cm long were placed in water and boiled with stirring throughout the process for 1 hour. The surface of the activated carbon fiber was then rinsed with deionized water until the filtrate was neutral. The mixture was placed in an oven at 120°C and dried for 12 hours. The mixture was removed, sealed, and dried for storage, and was designated as ACF-0. 1 g of ACF-0 was weighed and soaked in 100 ml of 1 mol / L NaOH solution and shaken at a constant temperature of 60°C for 3 hours. The mixture was rinsed with deionized water until the filtrate was neutral, and dried in an oven at 120°C for 12 hours. The mixture was removed, sealed, and dried for storage, and was designated as ACF-Na. The ACF-Na was then placed in a tubular heating furnace and heated to 600°C at 10°C / min under N2 protection. After keeping the temperature for 2 hours, the mixture was cooled to below 200°C and air-cooled. The mixture was removed, sealed, and dried for storage, and was designated as ACF-Na-HT.

[0062] Comparative Example 3

[0063] The composite material was prepared according to the method of Example 2, except that the preparation steps included:

[0064] (1) Preparation of modified cellulose: In order to remove impurities from activated carbon fibers, small pieces of activated carbon fibers cut into 1.5 cm long were placed in water and boiled with stirring for 1 hour. The surface of the activated carbon fibers was then rinsed with deionized water until the filtrate was neutral. The fibers were placed in an oven and dried at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-0. 1 g of ACF-0 was weighed and soaked in 100 ml of 1 mol / L NaOH solution and oscillated at 60°C for 3 hours. The fibers were rinsed with deionized water until the filtrate was neutral, and dried in an oven at 120°C for 12 hours. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na. The ACF-Na was then placed in a tubular heating furnace and heated to 600°C at 10°C / min under N2 protection. After keeping the temperature for 2 hours, the fibers were cooled to below 200°C and then air-cooled. The fibers were taken out, sealed, and dried for storage, and recorded as ACF-Na-HT.

[0065] (2) Preparation of conductive polymer: Add 20 ml of deionized water to a 50 ml beaker, then add 1 ml of aniline and concentrated hydrochloric acid, ultrasonicate for 10 minutes and stir, then add phytic acid solution (the mass ratio of phytic acid to aniline is 1:3) and ultrasonicate for 20 minutes. Then place the beaker in an ice water bath and stir, then slowly add ammonium persulfate solution (the molar ratio of aniline to ammonium persulfate is 1:1). Recorded as P-PANI

[0066] (3) Preparation of composite materials: After all the ammonium persulfate solution was added, ACF-NA-HT was added to the mixture. The addition ratio of aniline monomer to activated carbon fiber ACF-NA-HT was 1:1, and the mixture was completely absorbed into the mixture. The mixture was kept in an ice bath for 3 h. The reaction mixture was filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate was neutral. A dark green product, phytic acid-doped polyaniline / activated carbon fiber composite material, was obtained, which was recorded as P-PANI / ACF. The product was placed in a 60°C oven and dried for 24 h.

[0067] Application Examples

[0068] Application Example 1

[0069] An application of a conductive polymer-cellulose composite material, and a specific application method is as follows:

[0070] Step 1: Prepare a cadmium solution with a concentration of 60 mg / L;

[0071] Step 2: Weigh 0.05 g of the polyaniline / activated carbon fiber composite material prepared in Example 1 and add it to a beaker containing 30 mL of a cadmium solution with an initial concentration of 60 mg / L, and adjust the pH value to about 6.0;

[0072] Step 3: Use a constant temperature magnetic stirrer to oscillate at a constant temperature of 25°C and a rotation speed of 120 r / min for 4 h;

[0073] Step 4: Sample the solution periodically using a syringe, then filter the extracted solution using a 0.45 μm filter membrane, and determine the concentration of residual cadmium in the water sample and the cadmium content in the water sample at adsorption equilibrium using a flame atomic spectrophotometer;

[0074] Step 5: Use the formula To calculate the degradation rate of cadmium by the sample, Q and Q e are cadmium ion removal rate and adsorption amount at time t, respectively.

[0075] The adsorption effect of the polyaniline / activated carbon fiber composite material prepared in Example 1 is as follows Figure 3 As shown, the adsorption rate of cadmium by the polyaniline / activated carbon fiber composite material prepared in Example 1 is 90.7%. The composite material has a very high adsorption performance.

[0076] Application Example 2

[0077] An application of a conductive polymer-cellulose composite material, and a specific application method is as follows:

[0078] Step 1: Prepare a cadmium solution with a concentration of 60 mg / L;

[0079] Step 2: Weigh 0.05 g of the polyaniline / activated carbon fiber composite material prepared in Example 2 and add it to a beaker containing 30 mL of a cadmium solution with an initial concentration of 60 mg / L, and adjust the pH value to about 6.0;

[0080] Step 3: Use a constant temperature magnetic stirrer to oscillate at a constant temperature of 25°C and a rotation speed of 120 r / min for 4 h;

[0081] Step 4: Sample the solution periodically using a syringe, then filter the extracted solution using a 0.45 μm filter membrane, and determine the concentration of residual cadmium in the water sample and the cadmium content in the water sample at adsorption equilibrium using a flame atomic spectrophotometer;

[0082] Step 5: Use the formula To calculate the degradation rate of cadmium by the sample, Q and Q e are cadmium ion removal rate and adsorption amount at time t, respectively.

[0083] The adsorption effect of the polyaniline / activated carbon fiber composite material prepared in Example 2 is as follows Figure 3 As shown in the figure, the adsorption rate of cadmium by the polyaniline / activated carbon fiber composite material prepared in Example 2 is Cd 2+ The removal rate reaches 98.31%. The composite material has high adsorption performance.

[0084] Application Example 3

[0085] An application of a conductive polymer-cellulose composite material, and a specific application method is as follows:

[0086] Application of composite materials in soil:

[0087] Step 1: Prepare a 60 mg / L cadmium solution and add the prepared CdCl2 solution to the soil in a 1:1 solution to soil ratio.

[0088] Step 2: Weigh 60 mg / kg of cadmium-contaminated soil, add distilled water as the soil saturation solution, stir evenly, and let it stand for 24 hours until the soil reaches saturation due to the force. Then add it to the soil sample chamber and compact it;

[0089] Step 3: The electrokinetic remediation experiment without adding adsorbent is recorded as EKR-1, and the electrokinetic-adsorption combined remediation experiment using the adsorbent P-PANI / ACF prepared in Example 2 is recorded as EKR-4;

[0090] Step 4: The sampling points from anode to cathode are recorded as Q1, Q2, Q3, Q4, and Q5 respectively.

[0091] Step 5: Set the electric field strength to 2 V / cm and the power-on time to 120 h. Use 0.1 mol / L citric acid as the electrolyte in the cathode chamber. Use a peristaltic pump to complete the cyclic addition of the electrolyte. Measure and record the current changes at intervals.

[0092] Step 6: Use microwave digestion to digest the soil sample. Take 0.25g of air-dried, ground and sieved soil sample and place it in a polytetrafluoroethylene (PTFE) digestion tank. Add 6mlHNO3, 3mlHCl and 2mlHF in sequence. Place it in an acid remover and heat it at 120°C for 30 minutes. After cooling it to room temperature, place it in a microwave digester. After the reaction is completed, remove the digestion tank and cool it to room temperature. Transfer it to a volumetric flask and make up the volume with 1% dilute nitric acid. After standing in the volumetric flask for a period of time, filter it with a microporous filter membrane and measure the Cd content using AAS. Use the formula Calculate the Cd content in the soil sample W (mg / kg)

[0093] In the experiment, the electric field strength of electrokinetic remediation was 2V / cm, 0.1mol / L citric acid solution was added to the cathode by electrolyte circulation, and the remediation reaction time was 120h. Figure 4 As shown in the figure, the average removal rate reaches 76.94%, and the composite material has high adsorption performance.

[0094] Application Example 4

[0095] An application of a conductive polymer-cellulose composite material, and a specific application method is as follows:

[0096] Step 1: Prepare a cadmium solution with a concentration of 60 mg / L;

[0097] Step 2: Weigh 0.05 g of the polyaniline / activated carbon fiber composite material prepared in Example 3 and add it to a beaker containing 30 mL of a cadmium solution with an initial concentration of 60 mg / L, and adjust the pH value to about 6.0;

[0098] Step 3: Use a constant temperature magnetic stirrer to oscillate at a constant temperature of 25°C and a rotation speed of 120 r / min for 4 h;

[0099] Step 4: Sample the solution periodically using a syringe, then filter the extracted solution using a 0.45 μm filter membrane, and determine the concentration of residual cadmium in the water sample and the cadmium content in the water sample at adsorption equilibrium using a flame atomic spectrophotometer;

[0100] Step 5: Use the formula To calculate the degradation rate of cadmium by the sample, Q and Q e are cadmium ion removal rate and adsorption amount at time t, respectively.

[0101] The adsorption effect of the polyaniline / activated carbon fiber composite material prepared in Example 3 is as follows: Figure 3 As shown, the polyaniline / activated carbon fiber composite material prepared in Example 3 has an adsorption rate of cadmium and a Cd2+ removal rate of 94.45%. The composite material has a very high adsorption performance.

[0102] Comparative Application Example 1

[0103] The application method of Application Example 1 is followed, except that the electrokinetic-adsorption combined remediation experiment performed in step 3 without using activated carbon fiber is recorded as EKR-1.

[0104] Comparative application example 1 shows the adsorption effect. Figure 4 As shown, the average removal rate reached 53.54%.

[0105] Comparative Application Example 2

[0106] The application method of Application Example 1 was followed, except that in step 3, the activated carbon fiber ACF-0 prepared in Comparative Example 1 was weighed and subjected to an electrokinetic-adsorption combined repair experiment, which was recorded as EKR-2.

[0107] The adsorption effect of the activated carbon fiber prepared in Comparative Example 1 is as follows: Figure 4 As shown, the average removal rate reached 61.35%.

[0108] Comparative Application Example 3

[0109] The application method of Application Example 1 is followed, except that in step 3, the activated carbon fiber ACF-Na-HT prepared in Comparative Example 2 is weighed and the electrokinetic-adsorption combined repair experiment is recorded as EKR-3.

[0110] The adsorption effect of the activated carbon fiber ACF-Na-HT prepared in Comparative Example 2 is as follows: Figure 4 As shown, the average removal rate reaches 71.45%, which is lower than the cadmium adsorption rate of 76.94% of the polyaniline / activated carbon fiber composite material prepared in Example 3 with the same mass ratio, further highlighting the superiority of the preparation method of the present invention.

[0111] The above description is merely an exemplary embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A method for preparing a conductive polymer-cellulose composite material, characterized in that: The following steps are involved: S1: Preparation of modified cellulose: small pieces of activated carbon fiber (ACF) were boiled and stirred in water, then immersed in a NaOH solution and placed in a tubular heating furnace and heated under N2 gas protection to obtain ACF-Na-HT; S2: Preparation of a conductive polymer: Aniline and concentrated hydrochloric acid were added to deionized water, and the mixture was ultrasonicated for 10 to 30 minutes and then stirred. A phytic acid solution was then added and ultrasonicated for 10 to 30 minutes to prepare a mixed solution. The mixed solution was then placed in an ice water bath and stirred, and then an ammonium persulfate (APS) solution was slowly added dropwise to prepare a conductive polymer solution. S3: Preparation of a conductive polymer-cellulose composite material: ACF-Na-HT is added to the conductive polymer solution prepared in step S2, and the mixture is kept in an ice bath for 3 to 6 hours. The reaction solution is then filtered and repeatedly washed with deionized water and anhydrous ethanol until the filtrate is neutral. The product is dried in an oven at 60 to 90° C. for 12 to 24 hours to obtain a conductive polymer-cellulose composite material, designated as P-PANI / ACF. The conductive polymer-cellulose composite material is used in conjunction with electrokinetic remediation technology to remediate cadmium-contaminated soil. In step S2, the mass ratio of aniline to phytic acid is 3:1; the molar ratio of aniline to APS is 1:1; The mass ratio of aniline to ACF-Na-HT in step S2 and step S3 is 1:1-10.

2. The method for preparing a conductive polymer-cellulose composite material according to claim 1, characterized in that: The method for preparing the modified cellulose in S1 comprises the following steps: (1) Cut the activated carbon fiber (ACF) into small pieces and boil and stir in water for 1-2 h. Then rinse the ACF surface with deionized water until the filtrate is neutral. Dry the ACF in an oven at 120-150°C for 6-24 h. Take out and seal the ACF for dry storage. This is recorded as ACF-0. (2) Weigh 1g-5g of ACF-0 and soak it in 100ml-200ml of NaOH solution, shake it at a constant temperature of 60-90℃ for 1-3h, rinse it with deionized water until the filtrate is neutral, and dry it in an oven at 120-150℃ for 6-24h. This is recorded as ACF-Na. (3) Place ACF-Na in a tubular heating furnace and heat it to 600-900°C at 10°C / min under N2 gas protection. Keep it warm for 1-2 hours, then air-cool it, take it out, seal it, and store it in a dry place. It is recorded as ACF-Na-HT.

3. The method for preparing a conductive polymer-cellulose composite material according to claim 2, characterized in that: The concentration of the NaOH solution in step (2) is 1-8 mol / L.

4. An application of the conductive polymer-cellulose composite material prepared according to claims 1-3, characterized in that: The specific application method is: A: The device consists of a cathode chamber, an anode chamber, a soil chamber, and a DC power supply. The device is circular and made of acrylic, 10 cm high and 20 cm in diameter. The cathode chamber in the middle consists of two cylindrical hollow structures, one inside and one outside. The cathode and the other outside are made of graphite and stainless steel, respectively. The electrodes are cylindrical, 1 cm in diameter, and arranged in a regular hexagonal pattern. The distance between the cathode and the anode is 8 cm. The entire device also requires a porous separator, non-woven filter cloth, a peristaltic pump, and copper wire. B: After weighing 60 mg / kg cadmium-contaminated soil, distilled water was used as the soil saturation solution, stirred evenly, and allowed to stand for 24 hours. The soil was saturated by force and added to the soil sample chamber for compaction. To prevent the soil from entering the cathode chamber, non-woven cotton was arranged on the inner wall of the cathode chamber cylinder, and the P-PANI / ACF was filled in the cathode chamber cylinder so that its height remained consistent with the height of the soil. C: The electric field strength was set to 2 V / cm, the power was applied for 120 h, 0.1 mol / L citric acid was used as the electrolyte in the cathode chamber, and a peristaltic pump was used to circulate the electrolyte. The current changes were measured and recorded at intervals. D: The electrokinetic-adsorption combined repair with the addition of adsorbent P-PANI / ACF is recorded as EKR-4.

5. The use of a conductive polymer-cellulose composite material according to claim 4, characterized in that: The soil saturated solution in step B has a pH of 6.

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