A biochar loaded molybdenite adsorbent, a preparation method and application thereof

Abstract

The present application relates to the technical field of adsorbent, in particular to a kind of biochar load molybdenite adsorbent, preparation method and application thereof, its preparation method includes the following steps: S1.the preparation of biochar;S2.molybdenite pretreatment;S3.the preparation of biochar load molybdenite;S4.the preparation of adsorbent.The key problem of active component easy to fall off in physical simple mixing is solved by the synergistic effect of modified cleaning solution and modified impregnation solution, the stability of adsorbent is improved, and an internal Mo-Ni synergistic catalytic system is constructed with molybdenite.The synergistic effect of modified cleaning solution, modified impregnation solution and adsorption modifier greatly improves the activation efficiency and pollutant degradation capacity, and enhances the electrostatic adsorption capacity for typical anionic pollutants (such as sulfamethoxazole) in water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adsorbents, in particular to a biochar loaded molybdenite adsorbent, a preparation method and application thereof. BACKGROUND

[0002] The ubiquitous presence of modern sulfonamide antibiotics in the water environment and their potential ecological risks have attracted widespread attention. As an important class of antibacterial drugs, they have a significant inhibitory effect on both gram-positive and gram-negative bacteria, and have been widely used in the medical and livestock industries for a long time. Sulfamethoxazole (SMX) belongs to sulfonamide antibiotics, which is one of the most widely used antibiotics in the world and has been identified as a persistent pollutant. Due to its extensive use, SMX has been frequently detected in the environment. The molecular formula of SMX is C 10 H 11 N3O3S, which is a white crystalline powder, belongs to organic compounds, and is mainly used for the treatment of various infections caused by sensitive bacteria, etc. The substance is odorless, slightly bitter, and difficult to dissolve in water, but easy to dissolve in dilute hydrochloric acid, sodium hydroxide reagent or ammonia test solution, and can also be dissolved in methanol and ethanol.

[0003] Natural mineral-biochar composite material is a composite material prepared by co-pyrolysis of biochar and natural minerals. Molybdenite (Molybdenite) is a molybdenum disulfide (MoS2), which is the main source of molybdenum ore and is produced in Henan, Shaanxi and Liaoning, etc. Molybdenite includes different types such as hexagonal and trigonal crystal system, has a typical layered structure, a hardness less than a fingernail, and usually presents a scaly or fine-grained morphology, a lead gray appearance, and a strong metallic luster. MoS2 is widely used in advanced oxidation technology (AOPs) and has good activation effect on peroxymonosulfate (PMS). SUMMARY

[0004] In view of the shortcomings of the prior art, the purpose of the present application is to provide a biochar loaded molybdenite adsorbent, a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A preparation method of a biochar loaded molybdenite adsorbent, comprising the following preparation steps:

[0007] S1. Preparation of biochar: corn straw is washed with deionized water for 3-4 times, crushed and passed through a 200 mesh sieve, pyrolyzed in a vacuum oven at 190-210℃ for 100-120min, and cooled to room temperature to obtain biochar;

[0008] S2. Molybdenite pretreatment: After the molybdenite is washed 3-4 times by the modified cleaning solution, the molybdenite is dried, ground and sieved through a 200 mesh screen to obtain the pretreated molybdenite;

[0009] S3. Preparation of biochar loaded molybdenite: The biochar and the pretreated molybdenite are mixed and added to the modified impregnation solution, ultrasonically dispersed at a frequency of 40-50 kHz for 8-10 min, stirred at a speed of 300-400 r / min for 4-4.5 h, dried at 75-85 °C for 10-12 h, sieved through a 200 mesh screen, and pyrolyzed at 700-710 °C to obtain the biochar loaded molybdenite;

[0010] S4. Preparation of adsorbent: 40-50 parts of the biochar loaded molybdenite, 4-5 parts of the adsorption modifier and 150-200 parts of deionized water are mixed, ultrasonically dispersed at a frequency of 40-50 kHz for 8-10 min, stirred at a speed of 300-400 r / min for 1-2 h, dried at 80-90 °C for 10-12 h, ground and sieved through a 200 mesh screen to obtain the biochar loaded molybdenite adsorbent;

[0011] The preparation of the adsorption modifier includes the following steps:

[0012] S41. 8-10 parts of potassium persulfate and 0.5-0.8 parts of ferric nitrate are dissolved in 40-50 parts of deionized water, stirred at a speed of 300-400 r / min for 15-20 min to obtain a preliminary mixture;

[0013] S42. 0.5-1 parts of aluminum chloride, 0.5-0.8 parts of sodium silicate and 0.3-0.5 parts of cetyltrimethylammonium bromide are added to the preliminary mixture, ultrasonically dispersed at a frequency of 40-50 kHz for 5-10 min to obtain the adsorption modifier.

[0014] Preferably, the preparation of the modified cleaning solution includes the following steps:

[0015] S21. 1-2 parts of sodium dodecyl sulfate and 5-8 parts of isopropyl alcohol are added to 90-100 parts of deionized water, stirred at a speed of 300-400 r / min for 10-20 min to obtain a preliminary cleaning solution;

[0016] S22. 10-15 parts of 10% dilute hydrochloric acid is added to the preliminary mixture, stirred at a speed of 300-350 r / min for 10-15 min to obtain a secondary cleaning solution;

[0017] S23. 1-3 parts of citric acid and 0.3-0.6 parts of disodium ethylenediaminetetraacetate are added to the secondary cleaning solution, and the stirring is continued at a speed of 300-350 r / min for 15-20 min. After cooling to room temperature, the modified cleaning solution is obtained.

[0018] Preferably, the preparation of the modified impregnation solution comprises the following steps:

[0019] S31. 15-20 parts of anhydrous ethanol are mixed with 90-100 parts of deionized water, the pH is adjusted to 9-10 with ammonia water, 1.5-2.5 parts of gamma-aminopropyl triethoxysilane is added, and stirring is carried out at 40-50 DEG C in a water bath for 30-40 min to obtain a preliminary impregnation solution;

[0020] S32. 0.5-1 parts of nickel nitrate and 0.2-0.4 parts of cetyltrimethylammonium bromide are added to the preliminary impregnation solution, stirring is carried out at a speed of 300-350 r / min for 25-30 min, and the modified impregnation solution is obtained after standing for 1-2 h.

[0021] Preferably, the molybdenite contains 59.94% Mo and 40.06% S.

[0022] Preferably, the mass ratio of the biochar, the pretreated molybdenite and the modified impregnation solution in step S3 is 3:1:20-25.

[0023] Preferably, in step S3, the pyrolysis is that the sieved mixture is placed into a crucible, flattened and compacted, and placed in a muffle furnace, the muffle furnace is closed after reaching 700-710 DEG C, and the mixture is naturally cooled for 3-4 h.

[0024] Preferably, the mass concentration of the dilute hydrochloric acid in step S22 is 10%.

[0025] Preferably, the stirring speed in step S31 is 300-400 r / min.

[0026] A biochar-loaded molybdenite adsorbent prepared by the above preparation method.

[0027] Application of a biochar-loaded molybdenite adsorbent in degrading sulfamethoxazole in water.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The modified cleaning solution not only effectively removes the organic dirt and dust impurities on the surface of the molybdenite, but also chelates and removes the impurity metal ions on the edge of the molybdenite crystal lattice, avoiding the inhibition of these impurities on the subsequent catalytic reaction. At the same time, the mild acidic environment slightly etches the layered structure of the molybdenite, exposing more active sites, which provides an ideal interface for the subsequent reaction with the coupling agent in the modified impregnation solution.

[0030] 2、The modified cleaning solution and the modified impregnation solution synergistically solve the key problem that active components are prone to falling off in physical simple mixing, improve the stability of the adsorbent, and construct an internal Mo-Ni synergistic catalytic system with molybdenite.

[0031] 3、The modified cleaning solution, the modified impregnation solution and the adsorption modifier synergistically greatly improve the activation efficiency and the pollutant degradation capacity, and enhance the electrostatic adsorption capacity on typical anionic pollutants (such as sulfamethoxazole) in water. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A preparation process flow chart of the biochar loaded molybdenite adsorbent of the present application;

[0033] Figure 2 An SEM spectrum of the biochar prepared in Example 1 of the present application;

[0034] Figure 3 An SEM spectrum of the pretreated molybdenite prepared in Example 1 of the present application;

[0035] Figure 4 An SEM spectrum of the biochar loaded molybdenite adsorbent prepared in Example 1 of the present application;

[0036] Figure 5 Fourier infrared spectra of the biochar (BC), the pretreated molybdenite (Molybdenite), the biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and the used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)) obtained in Example 1 of the present application;

[0037] Figure 6 XRD spectra of the biochar (BC), the pretreated molybdenite (Molybdenite), the biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and the used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)) obtained in Example 1 of the present application;

[0038] Figure 7 XPS spectra of the biochar (BC), the pretreated molybdenite (Molybdenite), the biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and the used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)) obtained in Example 1 of the present application;

[0039] Figure 8A degradation rate fold line chart of SMX by different mass ratios of biochar and pretreated molybdenite of the present application;

[0040] Figure 9 A degradation rate fold line chart of SMX by biochar loaded molybdenite adsorbent obtained from example 1 of the present application at different pyrolysis temperatures;

[0041] Figure 10 A degradation rate fold line chart of SMX by different dosages of biochar loaded molybdenite adsorbent obtained from example 1 of the present application;

[0042] Figure 11 A degradation rate fold line chart of SMX by biochar loaded molybdenite adsorbent obtained from example 1 of the present application at different initial concentrations of SMX. DETAILED DESCRIPTION

[0043] The present application will be described in detail below with reference to the embodiments thereof, it is apparent that the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0044] Please refer to Figures 1-11 The present application provides a technical solution:

[0045] Example 1

[0046] A preparation method of a biochar loaded molybdenite adsorbent:

[0047] Before preparing the biochar loaded molybdenite adsorbent, the preparation of a modified cleaning solution, a modified impregnation solution and an adsorption modifier is performed:

[0048] The preparation of the modified cleaning solution comprises the following steps:

[0049] S21. 1g of sodium dodecyl sulfate and 5g of isopropyl alcohol are added to 90ml of deionized water, and stirred at a speed of 300r / min for 10min to obtain a preliminary cleaning solution;

[0050] S22. 10ml of dilute hydrochloric acid with a mass concentration of 10% is added to the preliminary mixed solution, and stirred at a speed of 300r / min for 10min to obtain a secondary cleaning solution;

[0051] S23. 1g of citric acid and 0.3g of ethylenediaminetetraacetic acid disodium are added to the secondary cleaning solution, and continue to be stirred at a speed of 300r / min for 15min, and the modified cleaning solution is obtained after cooling to room temperature;

[0052] The preparation of the modified impregnation solution comprises the following steps:

[0053] S31. Mix 15 ml of anhydrous ethanol with 90 ml of deionized water, adjust the pH to 9 with ammonia water, and then add 1.5 g of γ-aminopropyl triethoxysilane. Stir at a speed of 300 r / min in a water bath at 40℃ for 30 min to obtain a preliminary impregnation solution;

[0054] S32. Add 0.5 g of nickel nitrate and 0.2 g of cetyltrimethylammonium bromide to the preliminary impregnation solution, and stir at a speed of 300 r / min for 25 min. After standing for 1 h to mature, a modified impregnation solution is obtained;

[0055] The preparation of the adsorption modifier comprises the following steps:

[0056] S41. Dissolve 8 g of potassium peroxymonosulfate and 0.5 g of ferric nitrate in 40 ml of deionized water, and stir at a speed of 300 r / min for 15 min to obtain a preliminary mixture;

[0057] S42. Add 0.5 g of aluminum chloride, 0.5 g of sodium silicate, and 0.3 g of cetyltrimethylammonium bromide to the preliminary mixture, and ultrasonically disperse at a frequency of 40 kHz for 5 min to obtain an adsorption modifier;

[0058] S1. Preparation of biochar: Wash the corn straw with deionized water for 3 times, crush and pass through a 200-mesh sieve, pyrolyze in a vacuum oven at 190℃ for 100 min, and cool to room temperature to obtain biochar;

[0059] S2. Molybdenite pretreatment: After washing the molybdenite (Mo content of 59.94%, S content of 40.06%) with the modified washing solution for 3 times, dry, grind and pass through a 200-mesh sieve to obtain pretreated molybdenite;

[0060] S3. Preparation of biochar loaded molybdenite: Mix 60 g of biochar and 20 g of pretreated molybdenite into 400 ml of modified impregnation solution, ultrasonically disperse at a frequency of 40 kHz for 8 min, then stir at a speed of 300 r / min for 4 h, dry at 75℃ for 10 h, pass through a 200-mesh sieve, place in a crucible, flatten and compact, and place in a muffle furnace. After reaching 700℃, turn off the muffle furnace and let it cool naturally for 3 h to obtain biochar loaded molybdenite;

[0061] S4. Preparation of adsorbent: Mix 40 g of biochar loaded molybdenite, 4 g of adsorption modifier, and 150 ml of deionized water, ultrasonically disperse at a frequency of 40 kHz for 8 min, then stir at a speed of 300 r / min for 1 h, dry at 80℃ for 10 h, and grind to pass through a 200-mesh sieve to obtain biochar loaded molybdenite adsorbent.

[0062] Example 2

[0063] A method for preparing biochar-supported molybdenite adsorbent:

[0064] Before preparing the biochar-supported molybdenite adsorbent, the following steps are taken: Preparation of the modified cleaning solution, modified impregnation solution, and adsorption modifier.

[0065] The preparation of the modified cleaning solution includes the following steps:

[0066] S21. Add 2g sodium dodecyl sulfate and 8g isopropanol to 100ml deionized water and stir at 400r / min for 20min to obtain a preliminary cleaning solution;

[0067] S22. Add 15 ml of 10% dilute hydrochloric acid to the initial mixture and stir at 350 r / min for 15 min to obtain the second cleaning solution;

[0068] S23. Add 3g of citric acid and 0.6g of disodium ethylenediaminetetraacetate to the cleaning solution of the next step, and continue to stir at 350r / min for 20min. After cooling to room temperature, the modified cleaning solution is obtained.

[0069] The preparation of the modified impregnation solution includes the following steps:

[0070] S31. Mix 20 ml of anhydrous ethanol with 100 ml of deionized water, adjust the pH to 10 with ammonia, add 2.5 g of γ-aminopropyltriethoxysilane, and stir at 400 r / min for 40 min in a water bath at 50 °C to obtain the preliminary impregnation solution.

[0071] S32. Add 1g of nickel nitrate and 0.4g of cetyltrimethylammonium bromide to the initial impregnation solution, stir at 350r / min for 30min, and let stand for 2h to mature to obtain the modified impregnation solution;

[0072] The preparation of the adsorption modifier includes the following steps:

[0073] S41. Dissolve 10g of potassium persulfate and 0.8g of ferric nitrate in 50ml of deionized water and stir at 400r / min for 20min to obtain a preliminary mixture;

[0074] S42. Add 1g of aluminum chloride, 0.8g of sodium silicate, and 0.5g of cetyltrimethylammonium bromide to the preliminary mixture, and ultrasonically disperse at a frequency of 50kHz for 10min to obtain the adsorption modifier;

[0075] S1. Preparation of biochar: Corn stalks were washed four times with deionized water, crushed and passed through a 200-mesh sieve, pyrolyzed in a vacuum oven at 210℃ for 120 min, and then cooled to room temperature to obtain biochar.

[0076] S2. Molybdenite pretreatment: The molybdenite (Mo content of 59.94%, S content of 40.06%) was washed 4 times by the modified cleaning solution, dried, ground and passed through a 200 mesh sieve to obtain the pretreated molybdenite;

[0077] S3. Preparation of biochar loaded molybdenite: 60g of biochar and 20g of pretreated molybdenite were mixed into 500ml of modified impregnation solution, ultrasonically dispersed at a frequency of 50kHz for 10min, then stirred at a speed of 400r / min for 4.5h, dried at 85℃ for 12h, passed through a 200 mesh sieve, placed in a crucible, flattened and compacted, and placed in a muffle furnace. After reaching 710℃, the muffle furnace was turned off and allowed to cool naturally for 4h to obtain the biochar loaded molybdenite;

[0078] S4. Preparation of adsorbent: 50g of biochar loaded molybdenite, 5g of adsorption modifier and 200ml of deionized water were mixed, ultrasonically dispersed at a frequency of 50kHz for 10min, then stirred at a speed of 400r / min for 2h, dried at 90℃ for 12h, ground and passed through a 200 mesh sieve to obtain the biochar loaded molybdenite adsorbent.

[0079] Example 3

[0080] A method for preparing a biochar loaded molybdenite adsorbent:

[0081] Before preparing the biochar loaded molybdenite adsorbent, the modified cleaning solution, the modified impregnation solution and the adsorption modifier were prepared:

[0082] The preparation of the modified cleaning solution includes the following steps:

[0083] S21. 1.2g of sodium dodecyl sulfate and 6g of isopropyl alcohol were added to 92ml of deionized water, stirred at a speed of 320r / min for 12min to obtain a preliminary cleaning solution;

[0084] S22. 11ml of 10% mass concentration dilute hydrochloric acid was added to the preliminary mixed solution, stirred at a speed of 320r / min for 11min to obtain a secondary cleaning solution;

[0085] S23. 1.5g of citric acid and 0.4g of ethylenediaminetetraacetic acid disodium were added to the secondary cleaning solution, and stirring was continued at a speed of 320r / min for 16min. After cooling to room temperature, the modified cleaning solution was obtained;

[0086] The preparation of the modified impregnation solution includes the following steps:

[0087] S31. Mix 16 ml of anhydrous ethanol with 92 ml of deionized water, adjust the pH to 9.2 with ammonia water, and then add 1.7 g of γ-aminopropyl triethoxysilane. Stir at a speed of 320 r / min in a water bath at 42 °C for 32 min to obtain a preliminary impregnation solution;

[0088] S32. Add 0.6 g of nickel nitrate and 0.25 g of cetyltrimethylammonium bromide to the preliminary impregnation solution, and stir at a speed of 320 r / min for 26 min. After standing for 1.2 h to allow maturation, a modified impregnation solution is obtained;

[0089] The preparation of the adsorption modifier comprises the following steps:

[0090] S41. Dissolve 8.5 g of potassium peroxymonosulfate and 0.6 g of ferric nitrate in 42 ml of deionized water, and stir at a speed of 320 r / min for 16 min to obtain a preliminary mixture;

[0091] S42. Add 0.6 g of aluminum chloride, 0.6 g of sodium silicate, and 0.35 g of cetyltrimethylammonium bromide to the preliminary mixture, and ultrasonically disperse at a frequency of 45 kHz for 6 min to obtain an adsorption modifier;

[0092] S1. Preparation of biochar: Corn stalks are washed with deionized water for 3 times, crushed and passed through a 200-mesh sieve, pyrolyzed in a vacuum oven at 195 °C for 105 min, and cooled to room temperature to obtain biochar;

[0093] S2. Molybdenite pretreatment: The molybdenite (Mo content of 59.94%, S content of 40.06%) is washed with the modified washing solution for 3 times, dried, ground and passed through a 200-mesh sieve to obtain pretreated molybdenite;

[0094] S3. Preparation of biochar loaded molybdenite: Mix 60 g of biochar with 20 g of pretreated molybdenite and add to 420 ml of modified impregnation solution, ultrasonically disperse at a frequency of 45 kHz for 9 min, and then stir at a speed of 320 r / min for 4.2 h. Dry at 76 °C for 10.5 h, pass through a 200-mesh sieve, place in a crucible, flatten and compact, and place in a muffle furnace. After reaching 702 °C, turn off the muffle furnace and allow it to cool naturally for 3.2 h to obtain biochar loaded molybdenite;

[0095] S4. Preparation of adsorbent: Mix 42 g of biochar loaded molybdenite, 4.2 g of adsorption modifier, and 160 ml of deionized water, ultrasonically disperse at a frequency of 45 kHz for 9 min, and then stir at a speed of 320 r / min for 1.2 h. Dry at 82 °C for 10.5 h, grind and pass through a 200-mesh sieve to obtain biochar loaded molybdenite adsorbent.

[0096] Example 4

[0097] A preparation method of a biochar loaded molybdenite adsorbent

[0098] Before preparing the biochar loaded molybdenite adsorbent, a modified cleaning solution, a modified impregnation solution and an adsorption modifier are prepared:

[0099] The preparation of the modified cleaning solution comprises the following steps:

[0100] S21. 1.8g of sodium dodecyl sulfate, 7g of isopropyl alcohol are added to 95ml of deionized water, and stirred at a speed of 380r / min for 17min to obtain a preliminary cleaning solution;

[0101] S22. 14ml of 10% mass concentration dilute hydrochloric acid is added to the preliminary mixed solution, and stirred at a speed of 340r / min for 14min to obtain a secondary cleaning solution;

[0102] S23. 2.5g of citric acid and 0.5g of disodium ethylenediaminetetraacetate are added to the secondary cleaning solution, and continue to stir at a speed of 340r / min for 17min, and after cooling to room temperature, a modified cleaning solution is obtained;

[0103] The preparation of the modified impregnation solution comprises the following steps:

[0104] S31. 18ml of anhydrous ethanol and 97ml of deionized water are mixed, the pH is adjusted to 9.6 with ammonia water, and then 2.2g of gamma-aminopropyl triethoxysilane is added, and stirred at a speed of 370r / min for 38min under the condition of a water bath at 48℃ to obtain a preliminary impregnation solution;

[0105] S32. 0.8g of nickel nitrate and 0.35g of cetyltrimethylammonium bromide are added to the preliminary impregnation solution, and stirred at a speed of 340r / min for 28min, and after standing for 1.6h, a modified impregnation solution is obtained;

[0106] The preparation of the adsorption modifier comprises the following steps:

[0107] S41. 9.5g of potassium peroxymonosulfate and 0.7g of ferric nitrate are dissolved in 48ml of deionized water, and stirred at a speed of 380r / min for 18min to obtain a preliminary mixed solution;

[0108] S42. 0.8g of aluminum chloride, 0.7g of sodium silicate and 0.45g of cetyltrimethylammonium bromide are added to the preliminary mixed solution, and ultrasonically dispersed at a frequency of 45kHz for 8min to obtain an adsorption modifier;

[0109] S1. Preparation of biochar: corn straw is cleaned with deionized water for 4 times, crushed and passed through a 200 mesh sieve, pyrolyzed in a vacuum oven at 205℃ for 115min, and cooled to room temperature to obtain biochar;

[0110] S2. Molybdenite pretreatment: The molybdenite (Mo content of 59.94%, S content of 40.06%) was washed 4 times by the modified cleaning solution, dried, ground and sieved through a 200 mesh screen to obtain the pretreated molybdenite;

[0111] S3. Preparation of biochar loaded molybdenite: 60 g of biochar and 20 g of pretreated molybdenite were mixed into 480 ml of modified impregnation solution, ultrasonically dispersed at a frequency of 45 kHz for 9 min, then stirred at a speed of 380 r / min for 4.4 h, dried at 82°C for 11.5 h, sieved through a 200 mesh screen, placed in a crucible and flattened and compacted, and then placed in a muffle furnace. After reaching 708°C, the muffle furnace was turned off and allowed to cool naturally for 3.6 h to obtain the biochar loaded molybdenite.

[0112] S4. Preparation of adsorbent: 48 g of biochar loaded molybdenite, 4.8 g of adsorption modifier and 180 ml of deionized water were mixed, ultrasonically dispersed at a frequency of 45 kHz for 9 min, then stirred at a speed of 380 r / min for 1.6 h, dried at 88°C for 11.5 h, ground and sieved through a 200 mesh screen to obtain the biochar loaded molybdenite adsorbent.

[0113] Performance test:

[0114] 1. SEM characterization analysis

[0115] The structure and morphology of the biochar, pretreated molybdenite and biochar loaded molybdenite adsorbent prepared in Example 1 were analyzed by TESCAN MIRA LMS scanning electron microscope (Quattro S, Brno, CZE). The SEM images of the biochar, pretreated molybdenite and biochar loaded molybdenite adsorbent prepared in Example 1 are shown in Figures 1, 2 and 3, respectively. Figures 2-4 As can be seen from the figures, the biochar has a porous structure, which is conducive to the loading of the pretreated molybdenite and the adsorption of heavy metal ions. The pretreated molybdenite is mainly composed of Mo, S and other elements, and has an irregular flaky structure. The biochar loaded molybdenite adsorbent is a compact composite formed by the pretreated molybdenite particles distributed on the surface or in the pores of the biochar, and shows local metal grain aggregation. Molybdenum-based oxide particles of different sizes can be observed embedded in the pores of the biochar, which may be produced during the high-temperature pyrolysis process. A large number of metal particles are uniformly dispersed on the surface and in the pores of the biochar, and this structural feature is conducive to electron transfer during the catalytic process.

[0116] 2. Fourier infrared spectrum analysis

[0117] To better conduct performance testing, the biochar obtained in Example 1, the pretreated molybdenite, the biochar-supported molybdenite adsorbent, and the used biochar-supported molybdenite adsorbent were named BC, Molybdenite, Molybdenite@BC (new), and Molybdenite@BC (used), respectively. At 4500-4000 cm⁻¹ -1 Fourier transform infrared spectroscopy was used to analyze the characteristic regions, and... Figure 5 Fourier transform infrared (FTIR) spectra of the biochar (BC) obtained in Example 1 of this invention, pretreated molybdenite, biochar-supported molybdenite adsorbent (Molybdenite@BC (new)), and used biochar-supported molybdenite adsorbent (Molybdenite@BC (used)). The four different materials are compared at 1053.425 cm⁻¹. -1 1609.306cm -1 and 3434.118cm -1 The characteristic absorption peaks at these locations belong to the stretching undulations of CH, C=C, and -OH, respectively. Furthermore, Molybdenite and Molybdenite@BC (new) show peaks at 580.476 cm⁻¹. -1 A new Mo=O stretching vibration peak was observed, indicating that Molybdenite@BC(new) contains molybdenite oxide. The presence of the Mo=O group demonstrates the successful introduction of molybdenite into the composite material.

[0118] 3. BET Characterization Analysis

[0119] Using a Micromeritics ASAP2460 fully automated surface area and porosity analyzer (ASAP2460, Norcross, Georgia, USA), BET tests were conducted on four materials: BC, Molybdenite, Molybdenite@BC (new), and Molybdenite@BC (used). The BET specific surface area, average pore size, and total pore volume parameters for each material are shown in Table 1 below.

[0120] Table 1

[0121]

[0122] As shown in Table 1, the specific surface areas of BC, Molybdenite, and Molybdenite@BC (new) are 72.3758 m². 2 / g, 2.9189m 2 / g and 71.1043m 2 / g. The specific surface area of Molybdenite@BC (new) was lower than that of BC, which was due to the fact that part of Molybdenite filled into the pores of BC during the preparation of the biochar loaded molybdenite adsorbent, resulting in a decrease in the specific surface area. The specific surface area of Molybdenite@BC (used) was 195.8082 m 2 / g, which was much higher than that of the other three materials, which might be because Molybdenite had a chemical reaction during the reaction, producing new oxides and thus increasing its specific surface area.

[0123] 4. XRD characterization analysis

[0124] Figure 1 shows the XRD patterns of biochar (BC), pretreated molybdenite (Molybdenite), biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)). Figure 6 From the figure, it can be seen that after the introduction of Molybdenite, the XRD patterns of Molybdenite@BC (new) and Molybdenite@BC (used) both showed characteristic peaks of MoO2 at about 39.65° and 51.87° in 2θ; the characteristic peak of MoS2 consistent with Molybdenite was observed at about 14.29° in 2θ. The intensity of the characteristic peak corresponding to MoS2 in Molybdenite@BC (new) was weakened to some extent, which was because Molybdenite@BC (new) was prepared by compounding BC and Molybdenite, so its MoS2 content was slightly lower than that of Molybdenite.

[0125] 5. XPS characterization analysis

[0126] Figure 2 shows the XPS patterns of biochar (BC), pretreated molybdenite (Molybdenite), biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)). Figure 7XPS spectra of the biochar (BC) obtained in Example 1, the pretreated molybdenite, the biochar loaded molybdenite adsorbent (Molybdenite@BC (new)) and the used biochar loaded molybdenite adsorbent (Molybdenite@BC (used)). As can be seen from the figure, the BC sample is mainly composed of C and O elements, and the binding energies of C1s and O1s are 284.08 eV and 516.63 eV respectively, indicating that there are a large number of oxygen-containing functional groups such as carboxyl, hydroxyl and ester groups in the BC. The Molybdenite sample contains Mo element in addition to C and O elements, and the binding energy of Mo3d is 233.08 eV. The element composition of the Molybdenite@BC (new) sample is similar to that of the Molybdenite sample, but the binding energy of Mo3d is slightly lower, indicating that a certain interaction has occurred between Molybdenite and biochar.

[0127] 6. Explore the effect of the mass ratio of biochar and pretreated molybdenite on the degradation of SMX in water

[0128] On the basis of Example 1, the mass ratio of biochar and pretreated molybdenite was controlled to be 1:1.5, 2:1, 1:2, 1:1 and 1:3, respectively. Figure 8 The degradation rate of SMX for different mass ratios of biochar and pretreated molybdenite in the present application is shown in the line graph. The degradation rates for mass ratios of 1:1.5, 2:1, 1:2, 1:1 and 1:3 are 88.96%, 94.49%, 95.85%, 97.24% and 98.69%, respectively. The activation material with a mass ratio of 1:3 has the best degradation effect on SMX, which is due to the high molybdenum content of the activation material, thereby providing more active molybdenum sites.

[0129] 7. Explore the effect of different pyrolysis temperatures on the degradation of SMX in water

[0130] On the basis of Example 1, the pyrolysis temperature in step S3 was controlled to be 400℃, 500℃, 600℃, 700℃ and 800℃, respectively. Figure 9 The degradation rate of SMX for the biochar loaded molybdenite adsorbent obtained in Example 1 at different pyrolysis temperatures in the present application is shown in the line graph. The SMX degradation rates corresponding to pyrolysis temperatures of 400℃, 500℃, 600℃, 700℃ and 800℃ are 78.89%, 89.23%, 98.45%, 98.64% and 98.08%, respectively. The experimental results show that the total amount of pollutants degraded by the biochar loaded molybdenite adsorbent prepared at temperatures of 600℃, 700℃ and 800℃ is almost the same, but the biochar loaded molybdenite adsorbent prepared at a temperature of 700℃ has the fastest degradation rate of SMX within the first 30 minutes of the reaction.

[0131] 8. Investigate the effect of biochar-supported molybdenite adsorbent dosage on the degradation of SMX in water.

[0132] Appendix Figure 10 This is a line graph showing the degradation rate of SMX by different dosages of the biochar-supported molybdenum ore adsorbent obtained in Example 1 of the present invention. When the dosages are 60 mg / L, 80 mg / L, and 100 mg / L, the degradation rates of SMX are 93.92%, 97.16%, and 99.06%, respectively, showing a gradually increasing trend. However, as the dosage of the biochar-supported molybdenum ore adsorbent gradually increases, i.e., when the dosages are 120 mg / L and 140 mg / L, the degradation rates of SMX are 98.68% and 98.89%, respectively, showing a slight decreasing trend. The above experimental phenomena indicate that the best degradation effect is achieved when the dosage of the biochar-supported molybdenum ore adsorbent is 100 mg / L, and excessive addition of biochar-supported molybdenum ore adsorbent is of no practical significance. This phenomenon is caused by the fact that if the amount of biochar-loaded molybdenite adsorbent added is too large, some of the material will agglomerate in the solution and will not be completely diffused into the solution before the reaction, thus resulting in a slight decrease in degradation efficiency.

[0133] 9. Investigate the effect of initial SMX concentration on its degradation efficiency.

[0134] Appendix Figure 11 This is a line graph showing the degradation rate of SMX by the biochar-supported molybdenite adsorbent obtained in Example 1 of this invention at different initial SMX concentrations. The graph shows a negative correlation between the initial SMX concentration and the SMX degradation rate. After 60 min, the degradation rates corresponding to SMX concentrations of 2 mg / L, 4 mg / L, 6 mg / L, 8 mg / L, and 10 mg / L were 97.21%, 97.75%, 97.29%, 92.18%, and 90.04%, respectively. When the SMX concentration is low, the generated SO4... •- While effective at degrading pollutants, SMX concentrations can lead to two inhibitory effects: First, SMX and its intermediates are adsorbed onto the surface of the biochar-supported molybdenite adsorbent, occupying adsorption sites and inhibiting effective contact between PMS and the catalyst, resulting in insufficient free radical generation. Second, under the same degradation conditions, higher SMX concentrations require more free and non-free radicals to participate in the reaction, while the number of free and non-free radicals generated in the system remains relatively constant, ultimately leading to a decrease in pollutant degradation efficiency. Therefore, in the degradation reaction, when the pollutant concentration in the system is high, the amount of active substances capable of degrading pollutants is limited, resulting in low degradation efficiency; conversely, when the pollutant concentration in the reaction system is low, sufficient free radicals can be generated, leading to efficient pollutant degradation and higher degradation efficiency compared to high-concentration pollutants.

[0135] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since numerous changes, modifications, substitutions and variations can be made thereto without departing from the spirit and scope of the application as defined by the appended claims and their equivalents.

Claims

1. A method for preparing a biochar-supported molybdenite adsorbent, characterized in that, The preparation steps include the following: S1. Preparation of biochar: Wash corn stalks with deionized water 3-4 times, crush and pass through a 200-mesh sieve, pyrolyze in a vacuum oven at 190-210℃ for 100-120 min, and obtain biochar after cooling to room temperature; S2. Pretreatment of molybdenite: After washing molybdenite 3-4 times with modified cleaning solution, it is dried, ground and passed through a 200-mesh sieve to obtain pretreated molybdenite; S3. Preparation of biochar-supported molybdenite: Biochar and pretreated molybdenite were mixed and added to a modified impregnation solution. The mixture was ultrasonically dispersed at a frequency of 40-50 kHz for 8-10 min, stirred at a speed of 300-400 r / min for 4-4.5 h, dried at 75-85 ℃ for 10-12 h, passed through a 200-mesh sieve, and then pyrolyzed at 700-710 ℃ to obtain biochar-supported molybdenite. S4. Preparation of adsorbent: By mass, 40-50 parts of biochar-supported molybdenite, 4-5 parts of adsorption modifier and 150-200 parts of deionized water are mixed and ultrasonically dispersed at a frequency of 40-50kHz for 8-10 minutes, then stirred at a speed of 300-400r / min for 1-2 hours, dried at 80-90℃ for 10-12 hours, and ground through a 200-mesh sieve to obtain biochar-supported molybdenite adsorbent; The preparation of the adsorption modifier includes the following steps: S41. By mass, dissolve 8-10 parts of potassium persulfate and 0.5-0.8 parts of ferric nitrate in 40-50 parts of deionized water, and stir at 300-400 r / min for 15-20 min to obtain a preliminary mixture; S42. Add 0.5-1 parts aluminum chloride, 0.5-0.8 parts sodium silicate, and 0.3-0.5 parts hexadecyltrimethylammonium bromide to the preliminary mixture, and ultrasonically disperse at a frequency of 40-50 kHz for 5-10 min to obtain the adsorption modifier; The preparation of the modified cleaning solution includes the following steps: S21. By weight, add 1-2 parts sodium dodecyl sulfate and 5-8 parts isopropanol to 90-100 parts deionized water, and stir at 300-400 r / min for 10-20 min to obtain a preliminary cleaning solution; S22. Add 10-15 parts of 10% dilute hydrochloric acid to the initial cleaning solution and stir at 300-350 r / min for 10-15 min to obtain the secondary cleaning solution; S23. Add 1-3 parts of citric acid and 0.3-0.6 parts of disodium ethylenediaminetetraacetate to the cleaning solution in the next step, and continue stirring at a speed of 300-350 r / min for 15-20 min. After cooling to room temperature, the modified cleaning solution is obtained. The preparation of the modified impregnation solution includes the following steps: S31. By mass, mix 15-20 parts of anhydrous ethanol with 90-100 parts of deionized water, adjust the pH to 9-10 with ammonia, add 1.5-2.5 parts of γ-aminopropyltriethoxysilane, and stir for 30-40 minutes in a water bath at 40-50°C to obtain a preliminary impregnation solution. S32. Add 0.5-1 parts of nickel nitrate and 0.2-0.4 parts of hexadecyltrimethylammonium bromide to the preliminary impregnation solution, stir at 300-350 r / min for 25-30 min, and let stand for 1-2 h to obtain the modified impregnation solution.

2. The method for preparing a biochar-supported molybdenite adsorbent according to claim 1, characterized in that, The molybdenite contained 59.94% Mo and 40.06% S.

3. The method for preparing a biochar-supported molybdenite adsorbent according to claim 1, characterized in that, In step S3, the mass ratio of biochar, pretreated molybdenite, and modified impregnation solution is 3:1:20-25.

4. The method for preparing a biochar-supported molybdenite adsorbent according to claim 1, characterized in that, In step S3, the pyrolysis involves placing the sieved mixture into a crucible, spreading and compacting it, and then placing it in a muffle furnace. Once the temperature reaches 700-710℃, the muffle furnace is turned off, and the mixture is allowed to cool naturally for 3-4 hours.

5. The method for preparing a biochar-supported molybdenite adsorbent according to claim 1, characterized in that, The stirring speed in step S31 is 300-400 r / min.

6. A biochar-supported molybdenite adsorbent, characterized in that, It is prepared by the preparation method described in any one of claims 1-5.

7. The application of the biochar-supported molybdenite adsorbent according to claim 6 in the degradation of sulfamethoxazole in water.

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