Molybdenum disulfide loaded charcoal binary adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of adsorption materials. The invention provides a preparation method of a molybdenum disulfide loaded biochar binary adsorbent, which takes modified straw biochar (MBC) as a carrier, and successfully synthesizes a MoS2 nano-powder loaded biochar (MBC) binary adsorbent through an ultrasonic method and a one-step hydrothermal method. According to the technical scheme, the acting force between the prepared binary adsorbent and antibiotic molecules is higher, and the adsorbability to the antibiotic molecules is higher; wherein the introduction of MBC also effectively improves the disadvantage of easy hydrophobic agglomeration of MoS2, at the same time, the equilibrium adsorption time is shortened by nearly 3 times, the equilibrium adsorption capacity is improved by about 15%, and the quinolone antibiotics can be effectively removed under neutral and acidic conditions, so that the method has wide application prospects in the aspect of removing quinolone antibiotic pollutants.

Description

Technical Field

[0001] The invention relates to the technical field of adsorption materials, and in particular to a molybdenum disulfide-loaded biochar binary adsorbent and a preparation method and application thereof. Background Art

[0002] Antibiotics refer to chemical substances with anti-pathogen or other activities, with antibacterial or bactericidal effects, mainly including quinolones, β-lactams, tetracyclines and macrolides, and are currently one of the most effective drugs used in clinical treatment and the treatment of livestock infectious diseases. The use of these antibiotics has caused certain pollution to some rivers, lakes and local groundwater. According to statistics, the antibiotics in these water bodies mainly come from wastewater generated by sewage treatment plants, medical pharmaceuticals and aquaculture industries, among which quinolone antibiotics are one of the main sources of antibiotic pollution in water bodies.

[0003] Quinolone antibiotics are a class of antibacterial drugs that all have a common ketoacid skeleton structure and are artificially synthesized. They have not yet been found naturally in nature. This class of drugs has the advantages of wide antibacterial activity and good bactericidal properties. They are excellent in treating bacterial infections, making them have a wide range of applications and large usage, so they are frequently detected in water bodies. At present, quinolone antibiotics have developed to the fourth generation, among which the third generation of quinolone antibiotics are widely used in clinical and aquaculture industries due to their good medicinal properties and few side effects. Commonly used quinolone drugs include pefloxacin (PF), norfloxacin (NF), and levofloxacin (LF). Related studies have shown that this class of antibiotics is difficult to absorb and metabolize in animals and will be excreted from the body with metabolites. Due to its own stable properties and long half-life, it has a stronger accumulation capacity and persistence than other antibiotics. Therefore, the treatment of quinolone antibiotic wastewater is urgent.

[0004] At present, adsorbent materials that can remove antibiotics are divided into two major types: monoadsorbent materials and multi-adsorbent materials. Among them, monoadsorbent materials commonly used for adsorbing antibiotics include mineral materials, biomass materials, carbon-based materials and metal-based materials. However, monoadsorbent materials have the advantages of simple synthesis process and easy preparation, but have defects in adsorption performance such as adsorption time or adsorption amount. Compared with monoadsorbent materials, multi-adsorbent materials have more surface active sites and larger specific surface area. At the same time, synergistic effects may be formed between the multi-components of the constituent materials, which is beneficial to improve the adsorption performance of the materials. At present, the performance of existing multi-component adsorbent materials is uneven, and the effects between the components are not synergistic enough. Based on this, it is very necessary to improve the performance of the adsorbent and study to obtain a multi-component adsorbent material with stronger synergy between components and capable of achieving efficient removal of the target object. Summary of the invention

[0005] The purpose of the present invention is to provide a molybdenum disulfide-loaded biochar binary adsorbent and a preparation method thereof, using modified straw biochar (MBC) as a carrier, and successfully synthesizing MoS by ultrasonic method and one-step hydrothermal method. 2 Nanopowder-loaded biochar (MMBC) binary adsorbent has stronger interaction with antibiotic molecules and stronger adsorption capacity for antibiotic molecules, and has broad application prospects in removing quinolone antibiotic pollutants.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a molybdenum disulfide-loaded biochar binary adsorbent, comprising the following steps:

[0008] (1) mixing ammonium molybdate and thiourea and adding water to obtain a mixed solution A;

[0009] (2) mixing potassium hydroxide with biochar, soaking and drying, and then activating the biochar to obtain modified biochar;

[0010] (3) The modified biochar and ammonium molybdate are mixed and added to the mixed solution A in step (1), and ultrasonicated and reacted to obtain a binary adsorbent MMBC.

[0011] Preferably, in step (1), the molar mass ratio of ammonium molybdate to thiourea is 1:(4-6); and the volume ratio of the total mass of the mixture of ammonium molybdate and thiourea to water is 5g:(70-90)mL.

[0012] Preferably, the mass ratio of potassium hydroxide and biochar mixed in step (2) is (1-3):1.

[0013] Preferably, the soaking time in step (2) is 5-7 hours; the drying includes primary drying and secondary drying, the temperature of the primary drying is 70-90°C, and the temperature of the secondary drying is 100-110°C.

[0014] Preferably, the activation treatment is heating to 650-750°C and maintaining for 50-70 minutes, with a heating rate of 8-12°C / min.

[0015] Preferably, the pH value of the modified biochar in step (2) is neutral.

[0016] Preferably, the mass ratio of the modified biochar and ammonium molybdate mixed in step (3) is (0.5-20):1.

[0017] Preferably, the ultrasonic time in step (3) is 0.5-1.5 h; the reaction temperature is 180-200° C., and the reaction time is 8-12 h.

[0018] The present invention also provides a molybdenum disulfide-loaded biochar binary adsorbent MMBC prepared by the preparation method.

[0019] The present invention also provides a MoS 2 The nanomaterial is obtained by subjecting the mixed solution A to ultrasonic and hydrothermal reactions, followed by washing and drying.

[0020] Preferably, the ultrasonic time is 20-40 min; the temperature of the hydrothermal reaction is 180-200° C., and the hydrothermal reaction time is 6-12 h.

[0021] The present invention also provides the use of the molybdenum disulfide-loaded biochar binary adsorbent MMBC in removing quinolone antibiotics.

[0022] Preferably, the binary adsorbent MMBC is used at a concentration of 0.3-0.8 g / L, and the pH value during use is 5.0-6.0.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] 1. The technical solution of the present invention uses modified straw biochar (MBC) as a carrier and successfully synthesizes MoS by ultrasonic method and one-step hydrothermal method. 2 Nanopowder loaded biochar (MMBC) binary adsorption material. The order of binding force of MMBC10 binary material to three antibiotics PF, LF and NF is PF>NF>LF; adsorption kinetics studies show that the adsorption process conforms to the quasi-secondary kinetic adsorption process, mainly chemical adsorption; Langmuir model shows that the adsorption mode of this material is monolayer adsorption and easy to occur; thermodynamic studies show that the adsorption is an endothermic reaction and can proceed spontaneously at room temperature. Compared with monomaterials, the binary material MMBC10 has stronger adsorption of antibiotic molecules.

[0025] 2. The adsorption mechanism includes hydrogen bonding, electrostatic interaction, pore filling, complexation and π-π interaction. Compared with the mono-material, the interaction between the binary adsorption material MMBC prepared by the present invention and the antibiotic molecules is stronger.

[0026] 3. At room temperature 303K, with an addition amount of 0.01g of adsorbent material, a pH value of 6, and a 15mL PF antibiotic solution with a concentration of 100mg / L, the maximum adsorption capacity of the binary adsorbent material MMBC for the three antibiotic solutions PF, LF and NF were 198.58mg / g, 141.55mg / g and 197.36mg / g, respectively, indicating that MMBC10 has a high adsorption capacity for the three antibiotic solutions.

[0027] 4. The introduction of MBC in the technical solution of the present invention effectively improves the MoS 2 The disadvantage of easy hydrophobic agglomeration is overcome, and at the same time, the equilibrium adsorption time is shortened by nearly 3 times, the equilibrium adsorption amount is increased by about 15%, and the effective removal of quinolone antibiotics can be achieved under both neutral and acidic conditions. It has broad application prospects in the removal of quinolone antibiotic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 MoS synthesized at different reaction times 2 Adsorption performance test results diagram;

[0029] Figure 2 XRD patterns of BC and MBC;

[0030] Figure 3 XRD patterns of MBC and MMBC materials;

[0031] Figure 4 FESEM images of BC, MBC2 and MMBC10 ( Figure 4 (a) shows the FESEM spectrum of BC, (b) shows the FESEM spectrum of MBC2, (c) shows the FESEM spectrum of MMBC10 with a scale of 2 μm, and (d) shows the FESEM spectrum of MMBC10 with a scale of 1 μm);

[0032] Figure 5 is the EDS spectrum of MMBC10 ( Figure 5 (a) represents the element mapping selection, (b) represents the mapping of the C element in MMBC10, (c) represents the mapping of the Mo element in MMBC10, (d) represents the mapping of the S element in MMBC10, and (d) represents the EDS element total spectrum of MMBC10);

[0033] Figure 6 Transmission electron microscopy image of MMBC10 ( Figure 6 (a) represents TEM image, (b) represents HRTEM image);

[0034] Figure 7 is the XPS spectrum of MMBC10 ( Figure 7 (a) represents the XPS total spectrum, (b) represents the spectrum of C1s in MMBC10, (c) represents the spectrum of Mo 3d in MMBC10, and (d) represents the spectrum of S2p in MMBC10);

[0035] Figure 8 The BET test results of BC, MBC1, MBC2 and MBC3 are shown in Figure ( Figure 8(a) represents the adsorption isotherm, and (b) represents the pore size distribution diagram);

[0036] Fig. 9 The BET measurement results of MMBC10 are shown in Figure ( Fig. 9 (a) represents the adsorption isotherm, and (b) represents the pore size distribution diagram);

[0037] Fig.10 The adsorption performance test results of BC, MBC2 and MMBC materials are shown in the figure ( Fig.10 (a) represents the low adsorption amount curve, and (b) represents the high adsorption amount curve);

[0038] Fig.11 The effects of different time on the adsorption performance of MMBC10 for three antibiotics: PF, LF and NF;

[0039] Fig.12 The effect of different solid-liquid ratios on the adsorption performance of PF, LF and NF three antibiotics by MMBC10 material ( Fig.12 (a) represents PF, (b) represents LF, and (c) represents NF);

[0040] Fig.13 The effect of different pH values ​​on the adsorption performance of PF, LF and NF three antibiotics by MMBC10 material;

[0041] Fig.14 The effect of different ionic strengths on the adsorption performance of PF, LF and NF three antibiotics by MMBC10 material ( Fig.14 (a) represents PF, (b) represents LF, and (c) represents NF);

[0042] Fig.15 The adsorption kinetics fitting curve of MMBC10 adsorbing PF, LF and NF solutions ( Fig.15 (a) represents the pseudo-first-order kinetic equation diagram, (b) represents the pseudo-first-order kinetic linear equation diagram, (c) represents the pseudo-second-order kinetic equation diagram, (d) represents the pseudo-second-order kinetic linear equation diagram, (e) represents the liquid film diffusion equation diagram, and (f) represents the intra-particle diffusion equation diagram);

[0043] Fig.16 The isothermal adsorption fitting curve of MMBC10 adsorbing PF solution ( Fig.16 (a) represents the Langmuir equation, (b) represents the Freundlich equation, (c) represents the Temkin equation, and (d) represents the Dubinin-Radushkevich equation);

[0044] Fig.17The isothermal adsorption fitting curve of MMBC10 adsorbing LF solution ( Fig.17 (a) represents the Langmuir equation, (b) represents the Freundlich equation, (c) represents the Temkin equation, and (d) represents the Dubinin-Radushkevich equation);

[0045] Fig.18 The isothermal adsorption fitting curve of MMBC10 adsorbing NF solution ( Fig.17 (a) represents the Langmuir equation, (b) represents the Freundlich equation, (c) represents the Temkin equation, and (d) represents the Dubinin-Radushkevich equation);

[0046] Fig.19 Thermodynamic ΔG of MMBC10 θ Relationship diagram with T;

[0047] Fig. 20 FT-IR spectra of the adsorption material before and after adsorption of three antibiotics: PF, LF and NF;

[0048] Fig.21 The BET test results of the adsorption material before and after the adsorption of three antibiotics: PF, LF and NF ( Fig.21 (a) represents the isothermal adsorption curve, and (b) represents the pore size distribution diagram);

[0049] Fig. 22 The XPS spectra of MMBC10 before and after adsorption of three antibiotics: PF, LF and NF ( Fig. 22 (a) shows the XPS overall spectrum, (b) shows the spectrum of C1s in MMBC10, (c) shows the spectrum of Mo 3d in MMBC10, and (d) shows the spectrum of S2p in MMBC10). DETAILED DESCRIPTION

[0050] The present invention provides a method for preparing a molybdenum disulfide-loaded biochar binary adsorbent, comprising the following steps:

[0051] (1) mixing ammonium molybdate and thiourea and adding water to obtain a mixed solution A;

[0052] (2) mixing potassium hydroxide with biochar, soaking and drying, and then activating the biochar to obtain modified biochar;

[0053] (3) The modified biochar and ammonium molybdate are mixed and added to the mixed solution A in step (1), and ultrasonicated and reacted to obtain a binary adsorbent MMBC.

[0054] In the present invention, water is added after ammonium molybdate and thiourea are mixed to obtain a mixed solution A. The molar mass ratio of ammonium molybdate and thiourea in the present invention is preferably 1: (4-6), further preferably 1: (4.5-5.5), and further preferably 1: 5. The water added in the present invention is preferably deionized water, and the total mass of the mixture of ammonium molybdate and thiourea to the volume of water is preferably 5g: (70-90) mL, further preferably 5g: (75-85) mL, and further preferably 5g: 80 mL.

[0055] In the present invention, potassium hydroxide is mixed with biochar (BC), and the mass ratio of potassium hydroxide to biochar is preferably (1-3): 1, more preferably (1.5-2.5): 1, and more preferably 2: 1. Deionized water is added to allow BC to be immersed in potassium hydroxide, and then ultrasonic treatment is performed, and the ultrasonic treatment is preferably 0.3-0.8h, more preferably 0.4-0.7h, and more preferably 0.5h. After the ultrasonic treatment is completed, the BC is allowed to stand and soak at room temperature, and the soaking time is preferably 5-7h, more preferably 5.5-6.5h, and more preferably 6h.

[0056] In the present invention, the mixture obtained after soaking is dried, and the drying includes primary drying and secondary drying. The primary drying is preferably carried out in a water bath, and the temperature of the primary drying is preferably 70-90°C, more preferably 75-85°C, and more preferably 80°C; the primary drying is carried out until it is slightly dry, and the time of the primary drying is preferably 1-3h, more preferably 1.5-2.5h, and more preferably 2h. The secondary drying is preferably carried out in an oven, and the temperature of the secondary drying is preferably 100-110°C, more preferably 103-108°C, and more preferably 105°C; the preferred secondary drying is stopped until constant weight.

[0057] In the present invention, the material obtained by secondary drying is activated to obtain modified biochar (MBC). The activation treatment is preferably heated to 650-750°C and maintained for 50-70 minutes, more preferably heated to 680-720°C, and more preferably heated to 700°C; more preferably maintained for 55-65 minutes, and more preferably maintained for 60 minutes; the heating rate is preferably 8-12°C / min, more preferably 9-11°C / min, and more preferably 10°C / min.

[0058] In the present invention, the pH value of the modified biochar is neutral. Preferably, the material obtained after the activation treatment is washed with HCl solution and deionized water until the pH value is neutral, and then dried to constant weight to obtain the modified biochar with neutral pH value.

[0059] In the present invention, the modified biochar and ammonium molybdate are mixed, and the mass ratio of the modified biochar and ammonium molybdate is preferably (0.5-20):1, further preferably (5-15):1, and further preferably 10:1. The obtained mixture is added to the mixed solution A and stirred, and the stirring time is preferably 8-12 minutes, further preferably 9-11 minutes, and further preferably 10 minutes. After stirring, ultrasonic treatment is performed, and the ultrasonic time is preferably 0.5-1.5 hours, further preferably 0.8-1.2 hours, and further preferably 1 hour.

[0060] In the present invention, the mixture after ultrasonication is further reacted to obtain the binary adsorption material MMBC. The reaction temperature is preferably 180-200°C, more preferably 185-195°C, and more preferably 190°C; the reaction time is preferably 8-12h, more preferably 9-11h, and more preferably 10h. Further, after the reaction is completed, it can be washed with ethanol and deionized water to remove impurities, and dried at 80°C to constant weight, and sealed and stored for later use.

[0061] The present invention also provides a molybdenum disulfide-loaded biochar binary adsorption material MMBC prepared by the preparation method.

[0062] The present invention also provides a MoS 2 The nanomaterial is obtained by subjecting the mixed solution A to ultrasonic and hydrothermal reactions, and then washing and drying.

[0063] In the present invention, the mixed solution A obtained above is subjected to ultrasonic and hydrothermal reaction to obtain MoS 2 Nanomaterials. The ultrasonic time of the present invention is preferably 20-40min, further preferably 25-35min, further preferably 30min; the ultrasonic frequency is preferably 30-40kHz, further preferably 32-38kHz, further preferably 35kHz. The hydrothermal reaction of the present invention is preferably carried out in a high-pressure reactor, the temperature of the hydrothermal reaction is preferably 180-200℃, further preferably 185-195℃, further preferably 190℃; the hydrothermal reaction time is preferably 6-12h, further preferably 8-11h, further preferably 10h.

[0064] In the present invention, after the hydrothermal reaction, the product is cooled naturally, the black solid product is collected, and it is washed with deionized water and ethanol for multiple times until the impurities are completely removed, and then placed in a vacuum drying oven for 12 hours to obtain MoS 2 Nano powder.

[0065] The present invention also provides the use of the molybdenum disulfide-loaded biochar binary adsorbent MMBC in removing quinolone antibiotics.

[0066] In the present invention, the quinolone antibiotics include levofloxacin (LF), pefloxacin (PF) and norfloxacin (NF).

[0067] In the present invention, the use concentration of the binary adsorption material MMBC is preferably 0.3-0.8 g / L, and further preferably 0.5-0.7 g / L.

[0068] In the present invention, the pH value of the binary adsorption material MMBC when used is preferably 5.0-6.0, and more preferably 6.0.

[0069] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0070] Example 1

[0071] A method for preparing a molybdenum disulfide-loaded biochar binary adsorption material MMBC, the steps are as follows:

[0072] (1) ammonium molybdate and thiourea are mixed in a molar mass ratio of 1:5, and then deionized water is added to obtain a mixed solution A, wherein the total mass ratio of the mixture of ammonium molybdate and thiourea to the volume of water is 5 g:80 mL;

[0073] (2) Potassium hydroxide and biochar were mixed in a mass ratio of 2:1, deionized water was added to allow the biochar to be immersed in potassium hydroxide, ultrasonically cleaned for 0.5 h in an ultrasonic cleaner, and placed at room temperature for 6 h to allow the biochar to be completely impregnated. The impregnated mixture was heated in an 80°C water bath for preliminary drying until slightly dry, and finally dried at 105°C to constant weight; the obtained sample was placed in a crucible, activated in an atmosphere furnace, heated to 700°C at 10°C / min, and kept at a constant temperature for 60 min; the finished modified straw biochar was washed with 1 mol / L HCl solution and deionized water until the pH value was neutral, and then dried in a blast drying oven at 80°C to constant weight, and sealed for storage;

[0074] (3) The modified biochar and ammonium molybdate were mixed in a mass ratio of 10:1, added to the mixed solution A and stirred for 10 min, then ultrasonically treated for 1 h, transferred to a high-pressure reactor, reacted at 190 °C for 10 h to obtain the target product, and naturally cooled to room temperature; washed with ethanol and deionized water to remove impurities, dried at 80 °C to constant weight, and sealed for storage.

[0075] Example 2

[0076] A MoS 2Nanomaterials, preparation steps are as follows:

[0077] The mixed solution A described in Example 1 was ultrasonically cleaned for 30 min at room temperature, then transferred to a high-pressure reactor, and subjected to hydrothermal reaction in an oven at 190°C for 10 h. After natural cooling, the black solid product was collected, rinsed with deionized water and ethanol for several times until the impurities were completely removed, and then dried in a vacuum drying oven for 12 h. The obtained MoS 2 The nano powder is stored in a desiccator for future use.

[0078] Test Example 1

[0079] 1. Detection of antibiotic concentration

[0080] The concentrations of levofloxacin (LF), pefloxacin (PF) and norfloxacin (NF) in the third generation of quinolone antibiotics were detected by 752N ultraviolet spectrophotometer, and the linear regression equations of the three antibiotics were determined by the following method:

[0081] Weigh three antibiotics separately and prepare a stock solution with a concentration of 20 mg / L with deionized water. Pipette a certain amount of stock solution into a 50 mL volumetric flask and dilute to obtain standard solutions of 0, 2, 4, 6, 8 and 10 mg / L. Take distilled water as the reference solution and measure the absorbance A at the maximum wavelength of the antibiotic (PF: λ = 280 nm; LF: λ = 290 nm; NF: λ = 278 nm). The linear regression equation of the antibiotic is obtained with the concentration c (mg / L) as the independent variable and the absorbance A as the dependent variable. The fitting results are shown in Table 1.

[0082] Table 1 Linear regression equations of antibiotics PF, LF and NF

[0083] (two)

[0085] Static adsorption experiment. A certain mass of adsorbent was placed in a conical flask containing antibiotic wastewater, and ultrasonicated for 1 minute to evenly mix the adsorbent and antibiotics. The adsorbent was placed in a constant temperature water bath oscillator and the experiment was carried out at a rate of 130 rpm at a certain temperature. The upper liquid was centrifuged at the corresponding time, and the absorbance value of the obtained clarified liquid was measured by ultraviolet spectrophotometer. Substituted into the linear equation corresponding to each antibiotic, the residual concentration of the antibiotic in the system was obtained.

[0086] Under the adsorption conditions of room temperature 303K, MoS 2 The amount of nanomaterial added was 0.01 g, the pH value was 6, and the MoS synthesized at 190 ° C for 6, 8, 10, 12, and 14 h in 15 mL of 100 mg / L PF antibiotic solution was tested. 2Adsorption performance of nanomaterials on PF solution.

[0087] Equilibrium adsorption capacity q e The calculation formula for (mg / g) is:

[0088] In formula (1), q e (mg / g) is the amount of pollutants adsorbed by the adsorbent when adsorption equilibrium is reached; c e (mg / L) is the concentration of the remaining pollutant in the solution when adsorption reaches equilibrium; c 0 (mg / L) represents the initial concentration of pollutants in the solution; V(L) is the volume of the pollutant solution; M(g) is the mass of the adsorbent.

[0089] The results are as follows Figure 1 As shown in Figure 2, as the reaction time increases, the corresponding equilibrium adsorption amount also increases; when the adsorption time reaches 10h, MoS 2 The equilibrium adsorption amount of the nanomaterials increased slowly, and the equilibrium adsorption amount of the MoS nanomaterials with reaction time of 6 and 8 h was lower than that of the MoS nanomaterials with reaction time of 10, 12, and 14 h. 2 The equilibrium adsorption amount of the nanomaterials was (115.94, 116.53, 116.73 mg / g). When the reaction time reached 10 h, the crystallization of the material slowed down and the time required for crystallization became longer. Therefore, the adsorption results of the reaction time of 12 and 14 h were not significantly different from those of 10 h. Therefore, the MoS synthesized with a reaction time of 10 h was selected. 2 Research on the adsorption properties of nanomaterials.

[0090] Test Example 2

[0091] Based on the modified biochar preparation process described in Example 1, biochar (BC) was modified using KOH as a modifier, and MBC materials were prepared at a mass ratio of KOH to BC of 1, 2, and 3, respectively, and were recorded as MBC1, MBC2, and MBC3.

[0092] (I) XRD analysis

[0093] XRD analysis was performed on the original BC and the prepared MBC1, MBC2 and MBC3. The results are as follows: Figure 2 shown.

[0094] It can be seen that the BC spectrum shows the characteristic peaks of C itself and some impurity peaks. It is speculated that these impurity peaks correspond to the ash produced by high-temperature calcination of corn stalks, which is difficult to remove. However, the impurities contained in the modified MBC material will decrease with the increase of KOH dosage. When the mass ratio of KOH to BC is 2, the 2θ of the MBC material is located at about 27° and 43°, and the mantou peak belonging to biochar is more dispersed, and the impurity peak is significantly weakened, indicating that the amount of KOH used at this time has achieved a good modification effect. Therefore, MBC is selected in this chapter. 2 Materials as MoS 2 carrier material.

[0095] Based on the MMBC preparation process described in Example 1, MBC was used as a carrier to synthesize MMBC materials. MMBC was prepared at a mass ratio of MBC2 to ammonium molybdate of 0.5, 1, 5, 10, 15 and 20, respectively, and recorded as MMBC0.5, MMBC1, MMBC5, MMBC10, MMBC15 and MMBC20. Then, XRD analysis was performed respectively, and the results were as follows: Figure 3 shown.

[0096] When MBC2 and MoS 2 When the mass ratio is 0.5 and 1, the characteristic peaks at 2θ values ​​of 14.13°, 32.91°, 35.97°, and 58.76° correspond to MoS 2 The (002), (100), (103) and (110) crystal planes of the crystal indicate that the MMBC series materials have been successfully synthesized. 2 The ratio of materials increases, MoS on MMBC 2 The characteristic peaks of the crystal weakened accordingly. When the ratios reached 5, 10, 15 and 20, MoS 2 The characteristic peaks of the material cannot be detected, which may be related to MoS 2 is related to the lower load.

[0097] (II) FESEM analysis

[0098] FESEM analysis was performed on BC, MBC2 and MMBC10.

[0099] The results are as follows Figure 4 As shown in Figure 2, compared with BC, MBC2 has more porous structures and a rough surface. Apart from this, there are no obvious structural features, but MBC2 has a larger specific surface area and can provide more active sites. For MMBC10, it can also be observed that MoS 2 Nanomaterials are widely loaded on the surface of MBC2 in spherical form, which solves the problem of MoS 2Nanomaterials are prone to large-scale hydrophobic aggregation during the self-assembly process. 2 The particles grow on the surface of biochar, which also provides a large number of active sites for the adsorption process. 2 The nanoparticles are composed of countless MoS 2 The nanosheets are formed after aggregation, with a diameter of about 200nm and a large specific surface area. In addition, the outer surface of the particles is relatively rough, which greatly increases the contact area between the antibiotic and the adsorbent, which is conducive to the occurrence of the adsorption reaction.

[0100] According to the element mapping area of ​​MMBC10 and the EDS element spectrum, the presence of Si and Mg indicates the presence of magnesium silicate substances on the biochar, which is consistent with the conclusion of XRD. The three elements C, Mo, and S are evenly distributed on the surface of the biochar, which indicates that MoS 2 Successfully loaded onto MBC2 (such as Figure 5 shown).

[0101] (III) TEM analysis

[0102] The MMBC10 material was further observed by transmission electron microscopy.

[0103] The results are as follows Figure 6 As shown in the figure, it can be clearly seen that the flake-like material is evenly distributed on the MBC2 matrix material; after local magnification, regular lattice fringes can be observed, and the measured interplanar spacing is 0.62nm, corresponding to MoS 2 The crystal (002) plane proves that it is MoS 2 This further demonstrates that the MMBC10 binary composite material was successfully synthesized.

[0104] (IV) XPS analysis

[0105] XPS analysis was performed on MMBC10 material.

[0106] The results are as follows Figure 7 As shown in the full XPS spectrum, the presence of Mo, S, C and other elements indicates that the MMBC10 material has been successfully synthesized. In addition, the presence of Mg and Si elements once again proves the presence of magnesium silicate substances in biochar. According to the high-resolution spectrum of C1s, the binding energies at 284.80, 286.40 and 288.58 eV are derived from CC / C=C, CO and C=O respectively; according to the high-resolution spectrum of Mo 3d, the two strong characteristic peaks at 232.77 eV and 235.92 eV are attributed to Mo respectively. 4+ Mo 3d 5 / 2 and Mo 3d 3 / 2 , indicating that the Mo element is Mo 4+According to the high-resolution spectrum of S2p, the characteristic peaks at 164.88eV and 169.26eV belong to S2p 3 / 2 and S2p 1 / 2 , indicating that the S element is S 2- XPS analysis shows that MoS 2 The elements in the carbon have been loaded on the biochar.

[0107] (V) BET analysis

[0108] Determination of N of BC, MBC1, MBC2, MBC3, MMBC10 materials 2 Adsorption isotherms and pore size distribution.

[0109] The test results of the four materials BC, MBC1, MBC2 and MBC3 are as follows Figure 8 As shown in the figure, the BC graph is not closed, which may be due to the fact that the material itself is mostly macroporous and contains too many impurities, which makes it impossible to reach equilibrium during adsorption and desorption; MBC1, MBC2 and MBC3 all belong to type IV isotherms and H4 hysteresis loops, indicating that the adsorbent is a mixture of microporous and mesoporous structures, and contains narrow crack pores inside. Fig. 9 The pore size distribution diagram in the figure shows that the pore sizes are mostly distributed in the range of 2 to 30 nm, which verifies that most of the four materials are composed of mesoporous structures, and there are also a small number of microporous structures. Therefore, the material has a large specific surface area, which is conducive to the occurrence of adsorption reactions.

[0110] The results of MMBC10 are shown in Fig. 9 As shown, from N 2 Judging from the characteristics of the gas adsorption isotherm curve, this hysteresis loop also belongs to the IV type isotherm, H4 hysteresis loop. The pore size distribution diagram shows that the material has a mesoporous structure, and the pore size is mostly concentrated in 2 to 15 nm. Compared with the MBC material, it has more microporous structure.

[0111] Table 2 Average pore size, pore volume and specific surface area of ​​different materials

[0112]

[0113] Table 2 shows the specific surface area, pore volume and average pore size of materials such as BC, MBC1, MBC2, MBC3 and MMBC10 calculated by BJH theory based on the BET test results.

[0114] As shown in Table 2, the specific surface areas of BC, MBC1, MBC2 and MBC3 are 0.514, 26.611, 52.895 and 62.706 m 2 / g, and the average pore sizes are 30.403, 3.841, 3.832 and 3.809 nm, respectively. It can be seen that the specific surface area of ​​MBC material is much higher than that of BC, indicating that the modification greatly increases the specific surface area of ​​the material. The modification effects of MBC3 material and MBC2 are not much different. Considering the economic cost, MBC2 material is selected as the matrix to synthesize the binary adsorbent, which is consistent with the conclusion of XRD.

[0115] It can also be obtained that the specific surface area of ​​MMBC10 is 99.78m 2 / g, the average pore diameter is 3.812nm, and the pore volume is 0.245cm 3 / g, indicating that MMBC10 material has a larger specific surface area, a slightly smaller average pore size and a larger pore volume than MBC2, indicating that MoS 2 The introduction of gives the binary material a better specific surface area and pore structure, which is conducive to full contact with the reactants and improves the adsorption efficiency.

[0116] Test Example 3

[0117] (I) Adsorbent

[0118] At room temperature 303K, the amount of adsorbent material added is 0.01g, the pH value is 6, and the concentration of PF antibiotic solution is 100mg / L in 15mL. The adsorbent materials include BC, MBC2 and MMBC. The adsorption performance of BC, MBC2 and MMBC materials are tested respectively, and the adsorbent material with the best adsorption performance is selected.

[0119] The results are as follows Fig.10 As shown. According to the results of the low adsorption curve, it can be seen that the material BC has the lowest adsorption amount on the PF solution, the adsorption amount of MBC2 on the PF solution is higher than that of BC and MMBC0.5 materials, and the adsorption amount of MMBC1 and MBC2 materials on the PF solution is similar, indicating that the modified material is conducive to the adsorption reaction. According to the results of the high adsorption curve, it can be seen that the greater the proportion of MBC2 added in MMBC, the better the adsorption effect. When the ratio of MBC2 to ammonium molybdate reaches 10 and the adsorption time reaches 330min, the adsorption amount almost reaches the maximum equilibrium adsorption amount of 200mg / g. At this time, increasing the MBC2 content has almost no effect on the adsorption results, which may be due to the fact that MoS 2 This is because the content is too low and cannot effectively combine with antibiotic molecules. Therefore, MMBC10 material was selected as the research object.

[0120] (ii) Adsorption time

[0121] At room temperature 303K, the addition amount of MMBC10 material was 0.01g, the pH value was 6, and the concentration of PF, LF and NF in 15mL of three antibiotic solutions with a concentration of 100mg / L was investigated.

[0122] The calculation formula for the removal rate is:

[0123] Depend on Fig.11 It can be seen that when the adsorption time is 180 min, the removal rate of the three antibiotics by MMBC10 material reaches about 99%, and it can be considered that the adsorption equilibrium time has been reached. 2 Compared with nanomaterials, the time for MMBC10 to reach equilibrium adsorption was shortened by 540 min, and the removal rates of PF, LF and NF antibiotic solutions were increased by 17.2%, 25.98% and 13.96%, respectively, which was related to the large specific surface area and rich functional groups of biochar.

[0124] (III) Solid-liquid ratio

[0125] Under the conditions of room temperature 303K, pH value 6, adsorption time 180min, and the volume of the three antibiotics PF, LF and NF being 15mL, the amount of adsorption material added was changed (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8g / L) to study the effect of the concentration of MMBC10 binary adsorption material on the adsorption performance of the three antibiotics.

[0126] According to the adsorption effect diagram of MMBC10 material on three antibiotics, PF, LF and NF, it can be seen that ( Fig.12 ), with the increase of dosage, the residual concentration of adsorbate decreases continuously, and the corresponding removal rate increases continuously. When the adsorbent addition amount is 0.1g / L, the removal rates of PF, LF and NF in the solution are 46.91%, 19.74% and 29.34% respectively; when the dosage increases to 0.5g / L, 0.7g / L and 0.5g / L respectively, the removal rates of PF, LF and NF in the solution are 98.99%, 99.48% and 98.68% respectively. When the three adsorbates reach dynamic adsorption equilibrium, the removal rates are all about 99%. It can be considered that the addition amount at this time reaches the optimal solid-liquid ratio.

[0127] Under the premise of the same dosage, the removal rate of the binary material MMBC10 for the three antibiotics is in the order of PF>NF>LF from high to low, which may be attributed to the binding force between the material and the molecules. In addition, when the dosage increases to 0.3g / L, 0.5g / L, and 0.3g / L, the removal rate of the MMBC adsorbent for the adsorbate reaches that of MoS 2The removal effects of nanomaterials (79.94%, 70.58%, and 60.06%) can be attributed to the fact that the addition of MBC2 changes the 2 While MMBC10 has the disadvantage of being prone to hydrophobic aggregation, it has a richer pore structure and active sites.

[0128] (IV) Solution pH

[0129] At room temperature 303K, the solid-liquid ratios of MMBC10 material and three antibiotics, PF, LF and NF, were 0.5g / L, 0.7g / L and 0.5g / L respectively, the adsorption time was 180min, and the antibiotic concentration was 100mg / L. The effect of pH value on the adsorption effect of the material was studied.

[0130] Depend on Fig.13 It can be seen that when the pH value of MMBC10 for the adsorption of PF, LF and NF is between 2 and 6, the adsorption effect shows a slowly increasing trend. When the pH value is greater than 6, the adsorption amount shows a decreasing trend with the increase of the pH value. The stronger the alkalinity, the more obvious the decrease in the adsorption amount. The adsorption amount reaches the best at pH = 6, which are 198.70, 142.46 and 197.41 mg / g respectively. Therefore, subsequent experiments were carried out under the condition of pH = 6.

[0131] (V) Ionic strength

[0132] The effect of ion concentration on the adsorption effect was studied under the conditions of room temperature 303K, pH value 6, adsorption time 180min, solid-liquid ratios of 0.5, 0.7 and 0.5g / L respectively, and adsorbent concentration of 100mg / L.

[0133] The adsorption effect of MMBC10 on three antibiotics, PF, LF and NF, is shown in Figure 2. Fig.14 As shown in the figure, the addition of strong electrolyte NaCl has almost no effect on the adsorption of the adsorbent, which may be due to the + The competitive adsorption between ions and antibiotic molecules is weak; adding strong electrolyte CaCl with high-valent cations 2 , which will reduce the adsorption capacity of the adsorbent. The maximum inhibition of the adsorption capacity of PF, LF and NF is 104.29 mg / g, 58.48 mg / g and 122.89 mg / g respectively. This may be due to the large amount of Ca generated in the system. 2+ ions, while quinolone antibiotics can form stable complexes with high-valent metal cations through the carboxyl group, forming Ca 2+ -PF, Ca 2+ -LF、Ca 2+ -NF, etc., thereby inhibiting the carboxyl group of the antibiotic molecule from binding to the Mo in the adsorbent 4+The maximum inhibition of MMBC10 material on PF, LF and NF solutions was 104.29, 58.48 and 122.89 mg / g, respectively, which was higher than that of MoS 2 The maximum inhibition amounts of the nanomaterials (83.10, 43.99, and 87.05 mg / g) indicate that the ion resistance of MMBC10 is weaker than that of MoS 2 Nanomaterials.

[0134] Test Example 4

[0135] (I) Adsorption kinetics

[0136] The pseudo-first-order kinetic model and pseudo-second-order kinetic model were used to fit the experimental data obtained by MMBC10 adsorption of antibiotics. The fitting curves are shown in Fig.15 The fitting parameters are shown in Table 3.

[0137] Table 3 Fitting parameters of adsorption kinetic model of antibiotics adsorbed by MMBC10

[0138]

[0139] from Fig.15 The curve characteristics show that this process is more consistent with the pseudo-second-order kinetic model. 2 It can be seen that the fitting coefficients of the pseudo-second-order kinetic equations of the three antibiotic solutions are all above 0.99, which is consistent with Fig.15 In addition, the theoretical equilibrium amounts of PF, LF and NF fitted by the pseudo-second-order kinetic model are 197.35, 142.21 and 197.45 mg / g, respectively, which are closer to the experimentally achieved equilibrium adsorption amounts of 198.85, 141.55 and 197.36 mg / g. This indicates that the adsorption process of MMBC10 is similar to that of MoS 2 The materials are the same, and both are mainly based on chemical adsorption.

[0140] The linear fitting curve of the pseudo-second-order kinetic model shows that the intercepts of the fitting lines are all positive, which is consistent with the 2 The results of the materials are similar, so the same model (liquid film diffusion and intraparticle diffusion) is used to explore the diffusion mechanism of MMBC10 binary material during the adsorption process and the way to limit the adsorption rate. 2 It can be seen that the experiment is more consistent with the liquid film diffusion model, which is also consistent with MoS 2 The fitting results of the monolithic materials are consistent. Therefore, the step of controlling the adsorption rate of MMBC10 is similar to that of MoS 2The materials are similar, and both are mainly based on the liquid film diffusion and surface adsorption on the adsorbent surface. In addition, since MBC2 has a certain microporous structure, the antibiotic molecules will also have further intrapore diffusion. Therefore, the process of controlling the adsorption of antibiotics by MMBC10 is completed under the dominant control of the liquid film surface adsorption. There is a certain intraparticle diffusion, but the degree of fit is not high. This may be because MBC2 has a large specific surface area, resulting in the liquid film surface adsorption, which can make the antibiotic molecules in the solution completely adsorbed, so the intraparticle diffusion is not obvious.

[0141] (II) Adsorption isotherm

[0142] The adsorption performance of MMBC10 material on three antibiotic solutions with initial concentrations of 80-180 mg / L, including PF, LF and NF, was investigated at certain temperatures (303, 313 and 323 K). Four isothermal adsorption models, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich, were used to fit the experimental results. In addition, since MBC2 has a rich pore structure, it was also added to further explore the adsorption mechanism from an energy perspective.

[0143] The adsorption isotherm model fitting diagram of MMBC10 material adsorbing PF solution is shown in Fig.16 The fitting parameters are shown in Table 4. The overall fit of the binary materials to the four models is Langmuir>Temkin>Freundlich>Dubinin-Radushkevich. The Langmuir model has a higher degree of fit than the other three models, indicating that the active sites on the surface of the MMBC10 material are evenly distributed and can only adsorb a monolayer. At the same time, the R values ​​of the Langmuir and Freundlich equations for MMBC10 are L The value and 1 / n value are both below 0.01 and 0.20, which are much lower than MoS 2 Material R L The values ​​of K and 1 / n indicate that MMBC10 can adsorb PF solution more efficiently, which is consistent with the experimental results. F The values ​​are all above 190, much higher than MoS 2 Material K FThe value shows that the interaction between MMBC10 and PF is stronger, the adsorption effect is better, and the adsorption mode of MMBC10 is mainly chemical adsorption. The Temkin isotherm adsorption model is second only to the Langmuir model, indicating that there is a stronger interaction between MMBC10 and antibiotic molecules than that of monolayer materials. This chapter uses the Dubinin-Radushkevich model to verify the type of adsorption from an energy perspective. The adsorption free energy E values ​​are 73.9442, 141.6823 and 152.9797 kJ / mol, respectively, all higher than 18 kJ / mol, indicating that the adsorption process is chemical adsorption, which is consistent with the previous conclusion and increases with increasing temperature, indicating that the adsorption process is an endothermic reaction.

[0144] Table 4 Isothermal adsorption model fitting parameters of MMBC10 adsorption of PF solution

[0145]

[0146] The adsorption isotherm model fitting diagram of MMBC10 material adsorbing LF solution is shown in Fig.17 The fitting parameters are shown in Table 5. 2 The values ​​show that the fit of the binary materials to the four models is Langmuir>Dubinin-Radushkevich>Temkin>Freundlich. The adsorption process is more consistent with the Langmuir isotherm adsorption model, indicating that the adsorption is mainly based on chemical adsorption of the monolayer. It is also observed that the R L The 1 / n value is similar to that of the adsorption of PF solution, indicating that MMBC10 is also easy to adsorb LF solution and is better than nano-MoS 2 Monomaterial. The KF values ​​in the Freundlich isotherm adsorption model are all below 190, indicating that the interaction between MMBC10 and LF is weaker than that between MMBC10 and PF, which is consistent with the size relationship of the kinetic equilibrium adsorption amount. In addition, the Dubinin-Radushkevich model has a higher fitting degree than the Temkin model, indicating that the adsorption type can be effectively verified from an energy perspective. The adsorption free energy E values ​​are 64.7475, 80.6052, and 109.0587 kJ / mol, respectively, all higher than 18 kJ / mol, indicating that the adsorption process also belongs to chemical adsorption. The R fitted in the Temkin isotherm adsorption model of MMBC10 adsorbing LF solution 2 The value is lower than that of MMBC10 adsorbed on PF solution, which indicates that the interaction force between MMBC10 and LF molecules is lower than that between MMBC10 and PF molecules, which may be one of the reasons for the lower maximum equilibrium adsorption amount.

[0147] Table 5 Isothermal adsorption model fitting parameters of MMBC10 adsorption of LF solution

[0148]

[0149]

[0150] The adsorption isotherm model fitting diagram of MMBC10 material adsorbing NF solution is shown in Fig.18 The fitting parameters are shown in Table 6. The overall fit of the binary material MMBC10 to the four models is Langmuir>Temkin>Freundlich>Dubinin-Radushkevich. The conclusions obtained by the Langmuir, Freundlich and Temkin equations are similar to those of the first two, indicating that MMBC10 is easy to adsorb NF solution and there is a strong electrostatic force between the two. The fitting degree of the Temkin model is second only to the Langmuir model. In the process of MMBC10 adsorbing NF solution, electrostatic interaction is the main force, which is consistent with the conclusion that MMBC10 adsorbs PF solution. In addition, from the energy perspective of the Dubinin-Radushkevich fitting model to verify the adsorption type, the adsorption free energy E values ​​are 61.7500, 73.8636 and 102.8259 kJ / mol, respectively, all higher than 18 kJ / mol, indicating that the adsorption process also belongs to chemical adsorption.

[0151] Table 6 Isothermal adsorption model fitting parameters of MMBC10 adsorption of NF solution

[0152]

[0153] (III) Adsorption thermodynamics

[0154] The adsorption thermodynamics of MMBC10 nanomaterials on three antibiotic solutions, PF, LF and NF, were determined.

[0155] MMBC10 Thermodynamic ΔG θ The relationship with T is as follows Fig.19 As shown in Table 7, the fitting parameters of the adsorption thermodynamic model of antibiotics adsorbed by MMBC10 are shown in Table 7. When the three antibiotic molecules were adsorbed on MMBC10, the ΔGθ values ​​under the experimental temperature conditions were all negative and lower than those of the monolayer materials, indicating that the adsorption reaction can be carried out spontaneously and is faster than that of MoS 2 The adsorption process of the material is easier to occur; the ΔS of MMBC10 θ The values ​​are all positive and within 0.07 KJ·mol -1 ·K -1The above indicates that compared with monolithic materials, binary materials have a stronger affinity for the adsorption of antibiotic molecules such as PF, LF and NF, and the possibility of reversible reaction in the adsorption process is lower; ΔH θ The values ​​of are all greater than 0, indicating that the adsorption process is an endothermic reaction and heating is conducive to the adsorption, which is consistent with the previous conclusion.

[0156] Table 7 Fitting parameters of the adsorption thermodynamic model of antibiotics by MMBC10

[0157]

[0158]

[0159] Test Example 5

[0160] FT-IR spectral analysis, BET analysis and XPS analysis were carried out on MBC2 and MMBC10 materials before and after adsorption of antibiotics to observe the changes in the functional groups of MBC2 and MMBC10 materials, the specific surface area and pore size distribution of the materials, and the changes in the surface ion potential of the materials. (one)

[0162] The three antibiotics PF, LF and NF and the MMBC10 material after adsorption of the three antibiotics are denoted as A(A 1 )、B(B 1 ) and C(C 1 ), infrared spectra of various substances are as follows Fig. 20 shown.

[0163] By comparing the infrared spectra of MBC2 and MMBC10, we can see that 3380cm -1 and 1560cm -1 They are the OH stretching vibration peak and the benzene ring skeleton vibration peak, 1033cm -1 are CO stretching vibration peaks. These peaks are significantly enhanced in the infrared spectrum of MMBC10, indicating that MoS 2 The addition of 2-hydroxy-1-nitropropene makes these three groups activated in large quantities. -1 A more obvious Mo-S stretching vibration peak was found at 2 The Mo in MBC2 successfully combines with the S in MBC2. -1 The characteristic peaks at are the C=O stretching vibration peaks of the carboxylic acid molecules in the three antibiotics. Compared with the infrared spectra of the three antibiotics PF (A), LF (B) and NF (C), the infrared spectra of MMBC10 after adsorbing PF, LF and NF (A) 1 , B 1 and C 1) can be seen that the peak intensities of the three characteristic absorption peaks are significantly weakened, which may be due to the interaction between the C=O on the antibiotic molecule and the MoS on the surface of MMBC10. 2 A ligand complex was formed. At 1622 cm -1 and 1485cm -1 The change of the aromatic ring absorption peak at 3380 cm indicates that there may be π-π interaction in its binding mode, which is consistent with the conclusion of pH value. -1 The peak at 40° is significantly weakened, indicating that hydrogen bonding occurs between the phenolic hydroxyl functional groups of the binary material and the antibiotic molecules. In summary, the results of infrared spectroscopy analysis show that the adsorption mechanism of MMBC10 material includes complexation, π-π interaction and hydrogen bonding.

[0164] The adsorption isotherms and pore size distribution of the adsorbent MMBC10 before and after the adsorption of three antibiotics are shown in Figure 2. Fig.21 As shown, the MMBC10 materials after adsorbing three antibiotics, namely PF, LF and NF, are marked as A, B and C respectively. From the adsorption isotherm diagram, it can be seen that the adsorption isotherms of A, B and C are not closed, which is related to the fact that the adsorbent cannot reach equilibrium during adsorption and desorption.

[0165] Table 8 Average pore size, pore volume and specific surface area of ​​material MMBC10 before and after adsorption of antibiotics

[0166]

[0167] The specific surface area, pore volume and average pore size of the material MMBC10 before and after adsorption of antibiotics calculated according to the BJH theory are shown in Table 8. The specific surface areas of A, B and C are 58.269, 54.107 and 43.393 m 2 / g, much smaller than MMBC1099.788m 2 / g specific surface area. In addition, the pore volume decreased from 0.245nm to 0.094, 0.093 and 0.080nm, respectively, indicating that pore filling is one of the mechanisms for the adsorption of antibiotic molecules by MMBC10. (two)

[0169] The three antibiotics PF, LF and NF and the MMBC10 material after adsorption of the three antibiotics are denoted as A, B and C respectively. The XPS spectra of various substances are shown in Fig. 22 shown.

[0170] According to the XPS total spectrum, the peaks of three elements, Mo, S, and C, appear in the spectrum, indicating that these three elements are involved in the adsorption reaction. According to the C1s spectrum, after the adsorption of the three antibiotics, the characteristic peaks at 284.80eV belonging to CC and C=C are significantly reduced. This group may participate in the adsorption of antibiotics in the form of π-π bonds. The characteristic peaks at 286.40 and 288.58eV belonging to C=O and CO have increased to a certain extent, which may be caused by these oxygen-containing functional groups as π electron donors. The changes in the characteristic peaks of the functional groups indicate that the functional groups are involved in the adsorption process. According to the Mo 3d and S2p spectra, after the adsorption of the three antibiotics, the binding energies of the two characteristic peaks shifted from low potential to high potential to varying degrees. This shift is also called blue shift. Related studies have shown that this shift indicates that similar electrostatic and hydrogen bonding effects occur between the adsorbent and the adsorbate.

[0171] In summary, the adsorption mechanism of MMBC10 for the three antibiotic molecules is better than that of MoS 2 The material is more complex. The effect of ionic strength on adsorption performance and infrared spectrum analysis show that π-π interaction and complexation are one of its adsorption mechanisms. The adsorption process is mainly chemical adsorption, and the adsorption rate is mainly controlled by liquid film diffusion, which is stronger than the intra-particle diffusion of mono-materials. The adsorption process is more consistent with the Langmuir model and is mainly monolayer adsorption. The binding force between the antibiotic molecules is stronger than that of mono-materials, and electrostatic interaction is one of its mechanisms for adsorbing antibiotic molecules. The adsorption process is an endothermic reaction, which is consistent with the thermodynamic fitting results.

[0172] In summary, it can be seen that the interaction between the binary adsorption material prepared by the technical solution of the present invention and the antibiotic molecules is stronger, and the adsorption of antibiotic molecules is stronger; the introduction of MBC also effectively improves the MoS 2 The disadvantage of easy hydrophobic agglomeration is overcome, and at the same time the equilibrium adsorption time is shortened by nearly 3 times, the equilibrium adsorption amount is increased by about 15%, and the effective removal of quinolone antibiotics can be achieved under both neutral and acidic conditions.

[0173] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a molybdenum disulfide-loaded biochar binary adsorbent, characterized in that: The steps include: (1) mixing ammonium molybdate and thiourea and adding water to obtain a mixed solution A; (2) mixing potassium hydroxide with biochar, soaking and drying, and then activating the biochar to obtain modified biochar; (3) The modified biochar and ammonium molybdate are mixed and added to the mixed solution A in step (1), and ultrasonicated and reacted to obtain a binary adsorbent MMBC.

2. The preparation method according to claim 1, characterized in that: The molar mass ratio of ammonium molybdate to thiourea in step (1) is 1:(4-6); The volume ratio of the total mass of the mixture of ammonium molybdate and thiourea to water is 5g: (70-90)mL.

3. The preparation method according to claim 1, characterized in that: The mass ratio of potassium hydroxide and biochar mixed in step (2) is (1-3):

1.

4. The preparation method according to claim 1, characterized in that: The soaking time in step (2) is 5-7 hours; The drying includes primary drying and secondary drying, the temperature of the primary drying is 70-90°C, and the temperature of the secondary drying is 100-110°C; The activation treatment is to heat to 650-750° C. and maintain for 50-70 min, with a heating rate of 8-12° C. / min.

5. The preparation method according to claim 1, characterized in that: The pH value of the modified biochar in step (2) is neutral.

6. The preparation method according to claim 1, characterized in that: The mass ratio of the modified biochar and ammonium molybdate mixed in step (3) is (0.5-20): 1; The ultrasonic time in step (3) is 0.5-1.5h; The reaction temperature is 180-200° C., and the reaction time is 8-12 hours.

7. Molybdenum disulfide loaded biochar binary adsorbent MMBC prepared by the preparation method according to any one of claims 1 to 6.

8. A MoS2 nanomaterial, characterized in that: The mixed solution A according to claim 1 is subjected to ultrasonic and hydrothermal reaction, and then washed and dried to obtain; The ultrasound time is 20-40 minutes; The temperature of the hydrothermal reaction is 180-200° C., and the time of the hydrothermal reaction is 6-12 hours.

9. Use of the molybdenum disulfide loaded biochar binary adsorbent MMBC according to claim 7 in removing quinolone antibiotics.

10. The use according to claim 9, characterized in that: The binary adsorbent MMBC is used at a concentration of 0.3-0.8 g / L and a pH value of 5.0-6.0 during use.

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