CN115672280A - Preparation method of perfluorooctanoic acid adsorbent - Google Patents
Preparation method of perfluorooctanoic acid adsorbent Download PDFInfo
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- CN115672280A CN115672280A CN202211495305.5A CN202211495305A CN115672280A CN 115672280 A CN115672280 A CN 115672280A CN 202211495305 A CN202211495305 A CN 202211495305A CN 115672280 A CN115672280 A CN 115672280A
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- activated carbon
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- pyrrole
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- perfluorooctanoic acid
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- SNGREZUHAYWORS-UHFFFAOYSA-N perfluorooctanoic acid Chemical compound OC(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F SNGREZUHAYWORS-UHFFFAOYSA-N 0.000 title claims abstract description 43
- 239000003463 adsorbent Substances 0.000 title claims abstract description 15
- 238000002360 preparation method Methods 0.000 title claims abstract description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 271
- KAESVJOAVNADME-UHFFFAOYSA-N Pyrrole Chemical compound C=1C=CNC=1 KAESVJOAVNADME-UHFFFAOYSA-N 0.000 claims abstract description 70
- 239000007864 aqueous solution Substances 0.000 claims abstract description 11
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 34
- 239000008367 deionised water Substances 0.000 claims description 20
- 229910021641 deionized water Inorganic materials 0.000 claims description 20
- 238000005406 washing Methods 0.000 claims description 18
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 16
- 238000009832 plasma treatment Methods 0.000 claims description 15
- 238000004140 cleaning Methods 0.000 claims description 11
- 238000007605 air drying Methods 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 10
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- 239000007788 liquid Substances 0.000 claims description 9
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- ULUNQYODBKLBOE-UHFFFAOYSA-N 2-(1h-pyrrol-2-yl)-1h-pyrrole Chemical compound C1=CNC(C=2NC=CC=2)=C1 ULUNQYODBKLBOE-UHFFFAOYSA-N 0.000 description 3
- 241001411320 Eriogonum inflatum Species 0.000 description 3
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- LTVDFSLWFKLJDQ-UHFFFAOYSA-N α-tocopherolquinone Chemical compound CC(C)CCCC(C)CCCC(C)CCCC(C)(O)CCC1=C(C)C(=O)C(C)=C(C)C1=O LTVDFSLWFKLJDQ-UHFFFAOYSA-N 0.000 description 3
- YOALFLHFSFEMLP-UHFFFAOYSA-N azane;2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoic acid Chemical compound [NH4+].[O-]C(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F YOALFLHFSFEMLP-UHFFFAOYSA-N 0.000 description 2
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- 101001136034 Homo sapiens Phosphoribosylformylglycinamidine synthase Proteins 0.000 description 1
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Abstract
The invention discloses a preparation method of a perfluorooctanoic acid adsorbent, which is prepared by N 2 And carrying out in-situ grafting on the surface of the activated carbon treated by the plasma to generate polypyrrole. The invention couples the plasma modification technology with the monomer micromolecule polymerization technology, after the active carbon is treated by the plasma, the surface of the active carbon has a large number of free radicals, the capability of the active carbon for adsorbing and activating pyrrole is enhanced, and then FeCl is used for activating the active carbon at room temperature 3 The pyrrole is polymerized on the surface of the activated carbon to generate polypyrrole, so that the modified activated carbon has electropositivity in an aqueous solution, and the grafted polypyrrole is not easy to fall off from the surface of the activated carbon, thereby improving the adsorption rate and the adsorption capacity of the activated carbon on the perfluorooctanoic acid.
Description
Technical Field
The invention relates to the technical field of adsorption materials, and particularly relates to a preparation method of a perfluoro caprylic acid adsorbent.
Background
Perfluorooctanoic acid (PFOA) is commonly used as an oil-, water-and soil-repellent surfactant, dispersant and leveling agent because of its excellent stability, surface activity and hydrophobic-oleophobic properties. PFOA is an artificial chemical substance which is an organic substance formed by substituting fluorine atoms for hydrogen atoms in a perfluoroalkyl carbon chain. Because strong electronegativity of fluorine can form a layer of compact electron cloud on the periphery of a carbon chain, PFOA molecules are stable and difficult to degrade, and particularly in a system with slow water circulation exchange speed, such as underground water, PFOA is easy to accumulate to reach higher concentration, so that water body is polluted. Research team of Qinghua university surveys monitoring data of PFAS in drinking water of 66 cities in China, and finds that drinking water of multiple cities contains PFOA with higher concentration. It has been shown that PFOA can enter human body through respiratory tract, esophagus, etc., causing serious damage to human reproductive system, liver and kidney, and even possibly carcinogenesis. 2019. Annual PFOA is listed as persistent organic contaminant (POP) in appendix A of the St.Google convention. Therefore, the method for removing the PFOA with high speed, high efficiency and low cost is researched, and has important significance for ecological environment protection and human health.
Activated carbon is the most common carbon adsorbent material. The PFOA has large molecular size, certain hydrophobic characteristics and exists in solution in the form of perfluorooctanoate anion. Therefore, the removal of PFOA in an aqueous solution by utilizing the hydrophobic effect and electrostatic adsorption of the adsorbent is the most effective method. However, the surface of the common activated carbon contains a large number of oxygen-containing functional groups, the functional groups enable the surface of the activated carbon to be electronegative in an aqueous solution, and perfluorooctanoate ions are also electronegative in the aqueous solution, so that the perfluorooctanoate ions and the perfluorooctanoate ions are easily repelled to cause the reduction of the adsorption performance of the activated carbon on the perfluorooctanoate ions. In the prior art, other compounds which enable the activated carbon to be positive are grafted or loaded on the surface of the activated carbon, such as loaded metal cations or grafted 3-chloro-2-hydroxypropyl trimethyl ammonium chloride, so as to achieve the purpose of improving the adsorption effect, but the loaded metal ions are easy to fall off from the surface of the activated carbon to cause secondary pollution, and the long carbon chain of the epoxy grafted quaternary ammonium salt can increase the steric hindrance (atomic electron cloud overlap, which is expressed as repulsion) of PFOA adsorption, so that the improvement of PFOA adsorption performance is influenced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a preparation method of a perfluoro caprylic acid adsorbent, so as to solve the problems that the activated carbon in the prior art has poor adsorption effect on perfluoro caprylic acid in a water body and a compound loaded on the surface of the activated carbon is easy to fall off.
In order to solve the technical problem, the invention adopts the following technical scheme:
a preparation method of a perfluoro caprylic acid adsorbent specifically comprises the following steps:
step 1: screening the activated carbon, washing the activated carbon with deionized water, and drying the washed activated carbon for later use;
step 2: putting the activated carbon obtained in the step 1 into a plasma cleaning machine, and starting vacuum plasma treatment;
and 3, step 3: when the glow of the plasma cleaning machine is sent out, N is introduced 2 The processing time is 200-300 s;
and 4, step 4: mixing the activated carbon treated in the step 3 with a pyrrole solution, and then putting the mixture into a closed container for oscillation for 12h to 24h; wherein the concentration of the pyrrole solution is 0.1 to 3mol/L, and the solid-to-liquid ratio of the active carbon to the pyrrole solution is 1g: (10 to 50) mL;
and 5: carrying out suction filtration on the suspension obtained in the step 4, and sequentially washing and carrying out suction filtration on the obtained solid for multiple times by using an ethanol aqueous solution and a deionized water solution;
step 6: putting the product washed in the step 5 into a container, and adding FeCl 3 Continuously oscillating the solution for 6 to 10 hours; wherein FeCl 3 The concentration of the solution is 0.1 to 5mol/L, feCl 3 The volume ratio of the solution to the pyrrole solution isV(FeCl 3 Solution): v (pyrrole solution) = (5 to 1): 1;
and 7: and (4) carrying out suction filtration on the turbid liquid obtained in the step (6), washing the turbid liquid for multiple times by using deionized water, and then air-drying the turbid liquid to constant weight to obtain the perfluorooctanoic acid adsorbent.
In the prior art, in order to improve the PFOA adsorption performance of activated carbon, metal ions are often directly loaded on the surface of the activated carbon or compounds such as 3-chloro-2-hydroxypropyl trimethylammonium chloride are grafted. However, metal ions are easy to fall off, and the long-chain structure of the 3-chloro-2-hydroxypropyl trimethylammonium chloride can increase the steric hindrance of pollutant adsorption and block micropores of the activated carbon, so that the improvement of the adsorption performance of the activated carbon is adversely affected. The method can increase the adsorption amount of the activated carbon to the perfluoro caprylate ions and improve the adsorption speed of the activated carbon to the perfluoro caprylate ions by in-situ grafting and polymerizing on the surface of the activated carbon to generate the polypyrrole with positive electricity, so that the adsorption effect of the activated carbon to the perfluoro caprylate ions is improved, and the grafted polypyrrole is not easy to fall off from the surface of the activated carbon to cause secondary pollution.
Compared with the prior art, the invention has the following beneficial effects:
the method of the invention adopts the steps that firstly, the activated carbon is treated by plasma, firstly, the plasma treatment time and N are adjusted 2 The content of micropores of the activated carbon is increased by utilizing the etching effect of the plasma, so that the specific surface area of the activated carbon is increased, and the capability of adsorbing perfluorooctanoic acid radicals of the activated carbon is increased from the aspect of the hydrophobic effect of the activated carbon; secondly, the surface of the activated carbon is activated by plasma to generate a large amount of cation free radicals. These cationic radicals react with pyrrole to produce pyrrole cationic radicals, which are then reacted with FeCl 3 The pyrrole cation radicals generated under the oxidation of (2) collide to generate dicationic dipyrrole containing two cation radicals, and then the dipyrrole is subjected to disproportionation to generate a neutral dipyrrole. The charge neutral polypyrrole can be combined with the cationic free radical in the system to generate the cationic free radical of the polypyrrole, then the polypyrrole of the trimer is generated through disproportionation, and the polypyrrole is finally generated in cycles. Therefore, the generated polypyrrole is not easy to fall off from the surface of the activated carbon, and can show electropositivity in an aqueous solution, and the adsorption performance and the adsorption rate of the activated carbon on the perfluorooctanoic acid are improved from the aspect of electrostatic action.
Drawings
Fig. 1 is an SEM image of unmodified activated carbon.
FIG. 2 is an SEM photograph of polypyrrole-modified activated carbon obtained in example 2.
FIG. 3 is an SEM image of polypyrrole-modified activated carbon obtained in the comparative example.
FIG. 4 is a diagram for evaluating the performance of activated carbon adsorption of PFOA.
Detailed Description
The invention will be further explained with reference to the drawings and examples.
1. Examples of the embodiments
Example 1
(1) Sieving coconut shell activated carbon with a standard sieve, screening out activated carbon with the particle size of 20-60 meshes, washing with deionized water for 3-6 times, removing impurities and dust on the surface of the activated carbon, drying in a forced air drying oven at 110 ℃ to constant weight, cooling to room temperature, and packaging into a sample bag;
(2) Placing 2.5 g of coconut shell activated carbon obtained in the step (1) in the center of a plasma treatment cavity, closing a cavity door, starting a vacuum pump, vacuumizing the interior of the treatment cavity to enable the absolute pressure of the treatment cavity to be less than 5kPa, and starting a plasma cleaning machine after maintaining the pressure for 30 s. After glow of the plasma cleaning machine is emitted, adjusting N 2 The flow is 100 mL/min, after plasma treatment for 240 s, the vacuum pump is closed, when the reading of the vacuum meter is 0, pressure relief is completed, the hatch door is opened, and the active carbon is taken out.
(3) And (3) putting 2.5 g of the activated carbon treated by the plasma obtained in the step (2) into a dry and clean 50 mL conical flask with a ground opening, quickly adding 25 mL of pyrrole solution with the concentration of 1.0 mol/L into the conical flask, plugging a bottle stopper, putting the conical flask into a water bath constant-temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 12h to ensure that pyrrole can be uniformly adsorbed on the surface of the activated carbon.
(4) Washing the activated carbon obtained in step (3) with 50 vol.% ethanol aqueous solution and deionized water for 3-4 times, respectively, to remove free pyrrole on the surface of the activated carbon, and then transferring the activated carbon into a dry, clean 100 mL ground conical flask.
(5) Tapering to step (4)50 mL of 2 mol/L FeCl is added into a bottle 3 And putting the solution into a water bath constant-temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 8 h to ensure that pyrrole monomers are polymerized on the surface of the activated carbon to generate polypyrrole.
(6) And (4) carrying out suction filtration on the suspension obtained in the step (5), washing the polypyrrole-grafted activated carbon for 4-5 times by using deionized water, and then drying the polypyrrole-grafted activated carbon in a forced air drying oven at 110 ℃ to constant weight to obtain polypyrrole-modified activated carbon.
Example 2
(1) Sieving coconut shell activated carbon with a standard sieve, screening out activated carbon with the particle size of 20-60 meshes, washing with deionized water for 3-6 times, removing impurities and dust on the surface of the activated carbon, drying in a forced air drying oven at 110 ℃ to constant weight, cooling to room temperature, and packaging into a sample bag;
(2) Placing 2.5 g of coconut shell activated carbon obtained in the step (1) in the center of a plasma treatment cavity, closing a cavity door, starting a vacuum pump, vacuumizing the interior of the treatment cavity to enable the absolute pressure of the treatment cavity to be less than 5kPa, and starting a plasma cleaning machine after maintaining the pressure for 30 s. After glow of the plasma cleaning machine is emitted, adjusting N 2 The flow is 80 mL/min, after plasma treatment for 240 s, the vacuum pump is closed, the pressure relief is completed when the reading of the vacuum meter is 0, the hatch door is opened, and the activated carbon is taken out.
(3) And (3) putting 2.5 g of the activated carbon treated by the plasma obtained in the step (2) into a dry and clean 50 mL conical flask with a ground opening, quickly adding 25 mL of pyrrole solution with the concentration of 1.0 mol/L into the conical flask, plugging a bottle stopper, putting the conical flask into a water bath constant-temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 12h to ensure that pyrrole can be uniformly adsorbed on the surface of the activated carbon.
(4) Washing the activated carbon obtained in step (3) with 50 vol.% ethanol aqueous solution and deionized water 3-4 times, respectively, to remove free pyrrole on the surface of the activated carbon, and then transferring the activated carbon into a dry, clean 100 mL ground conical flask.
(5) Adding 50 mL of 2 mol/L FeCl into the conical flask in the step (4) 3 Placing the solution into a water bath constant temperature oscillator, and oscillating at room temperature at 100 r/minAnd oscillating for 8 h to polymerize pyrrole monomers on the surface of the activated carbon to generate polypyrrole.
(6) And (4) carrying out suction filtration on the suspension obtained in the step (5), washing the polypyrrole-grafted activated carbon for 4-5 times by using deionized water, and then drying the polypyrrole-grafted activated carbon in a forced air drying oven at 110 ℃ to constant weight to obtain polypyrrole-modified activated carbon.
Example 3
(1) Screening coconut shell activated carbon by using a standard sieve, screening out the activated carbon with the particle size of 20-60 meshes, washing the activated carbon for 3-6 times by using deionized water, removing impurities and dust on the surface of the activated carbon, drying the activated carbon in a forced air drying oven at 110 ℃ to constant weight, cooling the dried activated carbon to room temperature, and then filling the dried activated carbon into a sample bag;
(2) Placing 2.5 g of coconut shell activated carbon obtained in the step (1) in the center of a plasma treatment cavity, closing a cavity door, starting a vacuum pump, vacuumizing the interior of the treatment cavity to enable the absolute pressure of the treatment cavity to be less than 5kPa, and starting a plasma cleaning machine after maintaining the pressure for 20 s. After glow of the plasma cleaning machine is emitted, the flow of N2 is adjusted to be 100 mL/min, after plasma treatment is carried out for 240 s, the vacuum pump is closed, pressure relief is completed when the reading of the vacuum meter is 0, the cabin door is opened, and the active carbon is taken out.
(3) And (3) putting 2.5 g of the activated carbon treated by the plasma obtained in the step (2) into a dry and clean 50 mL conical flask with a ground opening, quickly adding 25 mL of pyrrole solution with the concentration of 3.0 mol/L into the conical flask, plugging a bottle stopper, putting the conical flask into a water bath constant temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 12h to ensure that pyrrole can be uniformly adsorbed on the surface of the activated carbon.
(4) Washing the activated carbon obtained in step (3) with 50 vol.% ethanol aqueous solution and deionized water for 3-4 times, respectively, to remove free pyrrole on the surface of the activated carbon, and then transferring the activated carbon into a dry, clean 100 mL ground conical flask.
(5) Adding 2 mol/L FeCl with 50 mL into the conical flask in the step (4) 3 And putting the solution into a water bath constant temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 8 h to polymerize pyrrole monomers on the surface of the activated carbon to generate polypyrrole.
(6) And (4) carrying out suction filtration on the suspension obtained in the step (5), washing the polypyrrole-grafted activated carbon with deionized water for 4-5 times, and then drying in a forced air drying oven at 110 ℃ to constant weight to obtain polypyrrole-modified activated carbon.
Comparative example A: the polypyrrole is directly grafted with the activated carbon without plasma pretreatment
(1) Screening coconut shell activated carbon by using a standard sieve, screening out the activated carbon with the particle size of 20-60 meshes, washing the activated carbon for 3-6 times by using deionized water, removing impurities and dust on the surface of the activated carbon, drying the activated carbon in a forced air drying oven at 110 ℃ to constant weight, cooling the dried activated carbon to room temperature, and then filling the dried activated carbon into a sample bag;
(2) Putting 2.5 g of the activated carbon obtained in the step (1) into a dry and clean 50 mL conical flask with a ground opening, quickly adding 25 mL of pyrrole solution with the concentration of 1.0 mol/L into the conical flask, plugging the conical flask with a bottle plug, putting the conical flask into a water bath constant temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 12h to ensure that pyrrole can be uniformly adsorbed on the surface of the activated carbon.
(3) Washing the activated carbon obtained in step (2) with 50 vol.% ethanol aqueous solution and deionized water for 3-4 times, respectively, to remove free pyrrole on the surface of the activated carbon, and then transferring the activated carbon into a dry, clean 100 mL ground conical flask.
(4) Adding 2 mol/L FeCl with 50 mL into the conical flask in the step (3) 3 And putting the solution into a water bath constant temperature oscillator, and oscillating at the room temperature at the speed of 100 r/min for 8 h to polymerize pyrrole monomers on the surface of the activated carbon to generate polypyrrole.
(5) And (4) carrying out suction filtration on the suspension obtained in the step (4), washing the polypyrrole-grafted activated carbon for 4-5 times by using deionized water, and then drying the polypyrrole-grafted activated carbon in a forced air drying oven at 110 ℃ to constant weight to obtain polypyrrole-modified activated carbon.
2. Study of Properties
The unmodified activated carbon, the polypyrrole-modified activated carbon obtained in example 1, example 3 and the control example were subjected to SEM characterization, and the obtained SEM characterization maps are shown in fig. 1, fig. 2 and fig. 3, respectively.
As can be seen from fig. 1, the unmodified activated carbon has a loose surface and a large number of macro pores. As can be seen from FIG. 2, many fluffy particles are attached to the surface of the activated carbon modified by the plasma treatment and the grafted polypyrrole, and the fluffy particles are the grafted polypyrrole. It can also be seen from fig. 2 that these synthesized substances are not peeled off from the surface of the activated carbon even after being washed with absolute ethanol and deionized water for many times, and polypyrrole and the surface of the activated carbon have strong bonding force, and are not easy to be peeled off from the surface of the activated carbon to cause secondary pollution.
As can also be seen from fig. 3, in the comparative example, polypyrrole grafted on activated carbon without plasma treatment mainly remained in pores (gaps) of activated carbon, and the surface was very small, indicating that polypyrrole grafted on activated carbon surface without plasma treatment easily fell off from the activated carbon surface when washed with absolute ethanol, deionized water, resulting in secondary pollution.
The performance evaluation of PFOA adsorption of the activated carbon modified by polypyrrole is carried out by adopting an adsorption kinetics experiment, and the activated carbon modified by the activated carbon, the example 1, the example 2, the example 3 and the comparative example. The method comprises the following specific steps:
(1) Preparing a perfluorooctanoic acid solution with a volume of 50 mg/L by using a volumetric flask, and filling the perfluorooctanoic acid solution into a plastic bottle for later use;
(2) Accurately weighing 50 mg of active carbon under different modification conditions in a 100 mL ground conical flask by using an analytical balance, and accurately sucking 50 mL of perfluorooctanoic acid solution in the conical flask by using a pipette to seal;
(3) Putting the conical flask into a water bath constant temperature oscillator, and reacting at room temperature; taking 1 mL of the supernatant into a 15 mL plastic tube every 12 hours, and adding excessive ammonia water to ensure that the perfluorooctanoic acid is completely reacted into ammonium perfluorooctanoate;
(4) And measuring the concentration of the ammonium perfluorooctanoate by an ultraviolet spectrophotometry method to further obtain the concentration of the PFOA.
As can be seen from fig. 3, when activated carbon is first plasma-treated and then modified with grafted polypyrrole, as in example 1, example 2 and example 3, the adsorption amount and adsorption rate of PFOA adsorption are higher than those of the original activated carbon.
Comparing example 1 with example 2, N when plasma treatment was performed 2 The flow rate is 80 mL/min, which is less than 100 mL/min of the example 1, the gas velocity is too low, the discharge is strongThe degree of the radical generated on the surface of the activated carbon was too weak, and the polypyrrole was grafted under the same synthesis conditions as in example 1, but the cationic radical on the surface of the activated carbon was less than that of example 1, and the polypyrrole was washed off more than that of example 1, and the polypyrrole was less grafted on the surface of the activated carbon, and the electrostatic adsorption force was small, and therefore the adsorption performance was lower than that of example 1.
Comparing example 1 with example 3, when polypyrrole modification is performed in example 3, the concentration of pyrrole added is 3.0 mol/L, which is greater than 1.0 mol/L of example 1, that is, more polypyrrole is grafted on the surface of activated carbon than in example 1, although more polypyrrole is grafted on the surface of activated carbon, the generated electrostatic adsorption force is greater, which is beneficial to adsorbing PFOA molecules. However, polypyrrole occupies some micropores or mesopores in the activated carbon, and the PFOA molecules are large, the length is about 1.19 nm, the width is about 0.38 nm, and the height is about 0.39 nm, so that excessive polypyrrole occupies PFOA adsorption sites and generates large adsorption steric hindrance for PFOA, and thus the activated carbon obtained in example 2 has lower PFOA adsorption performance than the activated carbon obtained in example 1. In contrast, in the comparative example, since the activated carbon is not subjected to the plasma treatment, the binding force between polypyrrole and the surface of the activated carbon is intermolecular force, and the binding force is weak, and when the activated carbon is washed with ethanol and water, the polypyrrole is easily detached from the surface of the activated carbon and is only grafted in micropores or mesopores.
It should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that the technical solutions of the present invention can be modified or substituted with equivalent solutions without departing from the spirit and scope of the technical solutions, and all should be covered in the claims of the present invention.
Claims (6)
1. The preparation method of the perfluorooctanoic acid adsorbent is characterized by comprising the following steps:
step 1: screening the activated carbon, washing the activated carbon with deionized water, and drying the washed activated carbon for later use;
and 2, step: putting the activated carbon obtained in the step 1 into a plasma cleaning machine, and starting vacuum plasma treatment;
and step 3: when the glow of the plasma cleaning machine is sent out, N is introduced 2 The processing time is 200-300 s;
and 4, step 4: mixing the activated carbon treated in the step 3 with a pyrrole solution, and then putting the mixture into a closed container for oscillation for 12h to 24h; wherein the concentration of the pyrrole solution is 0.1 to 3mol/L, and the solid-to-liquid ratio of the active carbon to the pyrrole solution is 1g: (10 to 50) mL;
and 5: carrying out suction filtration on the suspension obtained in the step 4, and sequentially washing and carrying out suction filtration on the obtained solid for multiple times by using an ethanol aqueous solution and a deionized water solution;
step 6: putting the product washed in the step 5 into a container, and adding FeCl 3 Continuously oscillating the solution for 6 to 10 hours; wherein FeCl 3 The concentration of the solution is 0.1 to 5mol/L, feCl 3 The volume ratio of the solution to the pyrrole solution isV(FeCl 3 Solution):V(pyrrole solution) = (5 to 1): 1;
and 7: and (4) carrying out suction filtration on the turbid liquid obtained in the step (6), washing the turbid liquid for multiple times by using deionized water, and then air-drying the turbid liquid to constant weight to obtain the perfluorooctanoic acid adsorbent.
2. The method for producing a perfluorooctanoic acid adsorbent according to claim 1, wherein in step 1, an activated carbon having a particle size of 20 to 60 mesh is screened.
3. The method of claim 1, wherein in step 2, after the absolute pressure inside the chamber of the plasma cleaning apparatus is less than 5kPa, the plasma treatment is started after waiting 30s to 60 s.
4. The method for producing a perfluorooctanoic acid adsorbent according to claim 1, wherein in step 3, N is 2 The flow rate is 80 mL/min to 120 mL/min.
5. The method for preparing a perfluorooctanoic acid adsorbent according to claim 1, wherein in the step 4, the concentration of the pyrrole solution is 0.5 to 3 mol/L; the solid-liquid ratio of the activated carbon to the pyrrole solution is 1g: (10 to 30) mL.
6. The method for preparing a perfluorooctanoic acid adsorbent according to claim 1, wherein in step 6, feCl is added in step 6 3 The concentration of the solution is 0.1-2 mol/L; feCl 3 The volume ratio of the solution to the pyrrole solution isV(FeCl 3 Solution):V(pyrrole solution) = (3 to 1): 1.
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