A method for removing antibiotics using MoS2-activated permanganate by ball milling

Abstract

This invention discloses a method for removing antibiotics from permanganate by ball milling MoS2 activation, belonging to the field of water treatment technology and environmental functional materials. The method includes: co-precipitation synthesis of MgAl-layered bimetallic hydroxide, hydrothermal composite formation, and ball milling bonding to obtain a ball-milled modified composite material and its water treatment application. This invention addresses the technical problems of existing permanganate activation technologies, such as the easy deactivation of active species in homogeneous systems, low activation efficiency in heterogeneous systems, and high interfacial electron transfer barriers due to only physical contact between materials. It employs sodium thiosulfate-assisted ball milling to induce chemical bonding, constructing a continuous electron transfer network that creates an electron-rich state on the MoS2 surface. Antibiotics are synergistically oxidized through a dual pathway of high-valence manganese intermediates and free radicals, while heavy metals are adsorbed using multiple mechanisms including sulfur coordination, sulfur vacancy anchoring, and hydroxyl complexation. Under optimal conditions, this method achieves a SMX removal rate of 96.8% and a lead ion removal rate of 99.2%.

Description

Technical Field

[0001] This invention relates to the fields of water treatment technology and environmental functional materials, and in particular to a method for removing antibiotics from MoS2 activated permanganate by ball milling. Background Technology

[0002] The combined pollution of antibiotics and heavy metals is a key challenge for the reuse of reclaimed water in agriculture. Antibiotics such as sulfamethoxazole and tetracycline often coexist with lead ions in the environment, making simultaneous and efficient removal difficult with traditional biological treatment technologies. Advanced oxidation technologies based on permanganate (PM) have attracted widespread attention in the water treatment field due to their strong oxidation capacity, ease of operation, and low byproduct production. However, permanganate itself has limited oxidation capacity and low removal efficiency for recalcitrant organic pollutants. Activation technologies are needed to generate high-valent manganese intermediates (Mn(VI) / Mn(V)) and reactive oxygen species to improve oxidation efficiency.

[0003] Currently, permanganate activation mainly employs homogeneous transition metal ions (such as Co). 2+ Fe 2+ Heterogeneous catalysts are used for both homogeneous and non-homogeneous activation. While homogeneous activation systems offer fast reaction rates, they suffer from drawbacks such as easy hydrolysis and deactivation of metal ions, narrow applicable pH ranges, short lifetimes of active species, and the risk of secondary pollution from residual metal ions. Among heterogeneous catalysts, layered molybdenum disulfide (MoS2) exhibits excellent permanganate activation potential due to its unique two-dimensional structure, abundant edge active sites, and tunable electronic properties. Existing studies have modified MoS2 using methods such as liquid-phase exfoliation and hydrothermal composites, but its activation efficiency remains limited by bottlenecks such as low active site density and poor electron transfer efficiency. Furthermore, the single MoS2 system mainly relies on the free radical activation pathway, making it susceptible to interference from natural organic matter and inorganic anions in the water.

[0004] To address these issues, researchers have attempted to composite MoS2 with iron-based materials, enhancing the activation capacity of permanganate through the redox cycle of iron species while utilizing the sulfur coordination sites of MoS2 to adsorb heavy metals. However, existing composite strategies often employ physical mixing or simple loading, resulting in only physical contact between MoS2 and iron-based materials. This leads to high interfacial electron transfer barriers, hindering atomic-level synergy; iron species are easily lost, resulting in poor cycle stability; and the materials have limited functionality, making it difficult to simultaneously achieve the multiple objectives of efficient permanganate activation, deep antibiotic degradation, and rapid heavy metal adsorption. Therefore, developing a method for preparing composite materials capable of constructing a chemically bonded interface between MoS2 and iron-based materials, enabling continuous electron transfer, and possessing multiple synergistic functions has significant technological value and application prospects. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for removing antibiotics from MoS2-activated permanganate by ball milling.

[0006] The technical solutions provided by the embodiments of the present invention are as follows:

[0007] A method for removing antibiotics using MoS2-activated permanganate by ball milling includes the following steps:

[0008] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0009] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 2-4:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5, and the solution was crystallized at 60-80℃ for 12-24 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0010] The process of co-precipitation synthesis of MgAl-layered bimetallic hydroxides can be divided into four consecutive stages. Each stage works synergistically through specific chemical and physical mechanisms to ultimately form a regular layered crystal structure:

[0011] The first stage: hydrolysis of metal ions and initial precipitation. When a mixed solution of magnesium and aluminum salts is slowly added dropwise to an alkaline solution containing sodium hydroxide and sodium carbonate, the pH of the solution rapidly rises to 9.5-10.5. Magnesium and aluminum ions immediately react with hydroxide ions to form initial precipitate nuclei of magnesium hydroxide and aluminum hydroxide, respectively.

[0012] Mg 2+ +2OH - →Mg(OH)2↓

[0013] Al 3+ +3OH - →Al(OH)3↓

[0014] Because the solution is in a supersaturated state, these precipitate nuclei exist in amorphous or microcrystalline form. Metal ions continuously accumulate on the surface of the precipitate nuclei through diffusion, causing the precipitate particles to gradually grow. Inert atmosphere protection is crucial at this stage, as it can effectively avoid interference from carbon dioxide dissolution in the air, ensure the stability of carbonate ion concentration, and thus guarantee the uniformity of anions between layers.

[0015] The second stage: isomorphous substitution and lamination construction. As the precipitation reaction proceeds, aluminum ions, with their similar ionic radii to magnesium ions (Mg... 2+ It is 0.072nm, Al 3+ With a wavelength of 0.053 nm and similar coordination chemistry, it gradually replaces some magnesium ion sites in the magnesium hydroxide layer. This isomorphous substitution process follows the principle of "structural compatibility." 3+ After entering the lamination, it forms an octahedral coordination structure with six hydroxyl groups, and then interacts with Mg. 2+A two-dimensional infinite network with shared edges is formed, due to Al 3+ The charge is higher than that of the substituted Mg 2+ The laminate thus acquires a positive charge, and its charge density is directly related to the amount of aluminum substitution (x value). Typically, x is controlled between 0.2 and 0.33 to ensure the stability of the laminate structure. At this time, a large number of hydroxyl functional groups (-OH) are exposed on the surface of the laminate. These hydroxyl groups can serve as chemical bonding sites in subsequent reactions, providing a structural basis for the formation of Fe-O-Al(Mg) hydroxyl bonds with iron species in this invention.

[0016] (1-x)Mg(OH)₂ + xAl(OH)₃ → [Mg 1-x Al x (OH)2] x+ +xOH -

[0017] The third stage: interlayer anion intercalation and charge balance. Positively charged layers have a strong tendency to adsorb anions, and carbonate ions (CO3-) in the solution... 2- Due to its high charge density and good geometric fit with the laminations, it preferentially inserts into the interlayer region. Carbonate ions bind to the laminations through electrostatic attraction and occupy the interlayer vacancies, balancing the excess positive charge of the laminations. At the same time, water molecules also enter the interlayer and form a hydrogen bond network with carbonate ions and hydroxyl groups of the laminations, thus forming a complete interlayer structure.

[0018] [Mg 1-x Al x (OH)2] x+ +x / 2CO3 2- →[Mg 1-x Al x (OH)2] x+ (CO3 2- ) x / 2

[0019] The intercalation of carbonate ions is a spontaneous thermodynamic process driven by the energy released by the neutralization of system charges. The type and number of interlayer anions directly affect the size of the interlayer spacing, which has a decisive influence on the ion exchange reaction in the subsequent heavy metal ion adsorption process.

[0020] The fourth stage: crystallization growth and structural regularization. At a crystallization temperature of 60-80℃, the system energy increases, the atomic diffusion rate accelerates, and the metal ions and hydroxyl groups within the layers rearrange, gradually reducing crystal defects and making the layer structure more complete. During crystallization, small grains grow continuously through a dissolution-recrystallization mechanism, forming layered double metal hydroxide (LDH) crystals with regular hexagonal crystal form and good crystallinity. The crystallization time (12-24h) is a key parameter for controlling crystal size and crystallinity. If the time is too short, the crystal will be incomplete and the active sites will not be exposed enough. If the time is too long, the grains may grow excessively and the specific surface area will decrease. After crystallization, the free ions and impurities are removed by centrifugation and washing, and then the physically adsorbed water is removed by vacuum drying. Finally, a MgAl-layered double metal hydroxide material with a clear layered structure, high specific surface area and abundant active sites is obtained, providing an ideal substrate and structural template for the subsequent in-situ growth of MoS2.

[0021] S2, Hydrothermal Composite:

[0022] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 5-20 g / L. A molybdenum source and a sulfur source were added at a molar ratio of 1:3-5, and the mass ratio of MgAl-layered bimetallic hydroxide to the molybdenum source was 5-10:1. The mixture was ultrasonically dispersed for 20-60 min, then transferred to a high-pressure reactor and hydrothermally reacted at 180-220℃ for 12-24 h. After centrifugation, washing, and drying, a MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0023] When the reaction system is heated to 180-220℃ in a closed high-pressure reactor, the hydrothermal conditions promote the thermal decomposition of thiourea or thioacetamide. Taking thiourea as an example, in the hydrothermal environment, the carbon-sulfur double bond in the thiourea molecule undergoes hydrolysis and breakage, generating carbon dioxide, ammonia and hydrogen sulfide gas. Since the reactor is under high pressure, hydrogen sulfide exists in the hydrothermal solution in a dissolved state rather than escaping from the system. This provides a sufficient sulfur source for the subsequent sulfidation reaction. The release rate of hydrogen sulfide is positively correlated with the reaction temperature. The higher the temperature, the faster the sulfur source decomposes and the higher the concentration of hydrogen sulfide, which is conducive to the rapid nucleation of MoS2.

[0024] CH4N2S + 2H2O → CO2 + NH3 + H2S

[0025] Ultrasonic dispersion pretreatment (20-60 min) ensured that LDH particles were uniformly suspended in the solution, creating conditions for the uniform deposition of MoS2 on the LDH surface and preventing LDH particles from agglomerating in the early stage of the reaction.

[0026] In a reducing hydrothermal environment, molybdate ions (MoO4) in the solution 2-The molybdate ions are gradually reduced by hydrogen sulfide and undergo a sulfidation reaction, a process that follows a "dissolution-reduction-precipitation" mechanism: First, the molybdate ions react with hydrogen sulfide to form the thiomolybdate intermediate (MoS4). 2- ), which eventually transforms into MoS2 with a layered structure;

[0027] MoO4 2- +4H2S+2H + →MoS2↓+4H2O+S2 2-

[0028] The driving force of this reaction comes from the strong reducing environment provided by hydrogen sulfide under hydrothermal conditions and the reaction kinetics promoted by high temperature and high pressure. The pH value of the reaction system plays a key regulatory role at this stage. The inherent alkaline microenvironment on the LDH surface can neutralize the acidic substances generated by the reaction and maintain a suitable pH range, thereby promoting the crystal growth of MoS2. The abundant hydroxyl functional groups on the magnesium aluminum LDH layer not only provide a local alkaline environment for the solution, but also serve as nucleation sites, reducing the energy barrier for heterogeneous nucleation of MoS2.

[0029] When the concentration of MoS2 in the solution reaches supersaturation, MoS2 molecules begin to nucleate. Since homogeneous nucleation requires overcoming a high surface energy barrier, while the LDH surface provides a large number of low surface energy nucleation sites, MoS2 preferentially undergoes heterogeneous nucleation on the LDH surface. There is a strong interfacial interaction between the magnesium and aluminum atoms exposed on the LDH plates and the sulfur atoms on the edges of MoS2. This force guides the MoS2 nuclei to oriented along the LDH surface. As the reaction time increases (12-24h), the MoS2 nuclei at the nucleation sites continuously absorb the molybdenum and sulfur sources in the solution and grow into nanosheet-like crystals in the horizontal direction.

[0030] MoS2+LDH→MoS2@LDH

[0031] Due to the structural guidance effect of the LDH layer, MoS2 nanosheets tend to spread and grow in a manner parallel to the LDH layer, forming a tightly bonded heterogeneous interface. In this process, MgAl-LDH not only serves as a growth substrate, but the hydroxyl groups on its layer surface can also form hydrogen bonds with the sulfur atoms at the edge of MoS2, further enhancing the interfacial bonding strength.

[0032] As the hydrothermal reaction proceeds, the MoS2 nanosheets gradually transform from their initial amorphous state into a well-crystallized 2H phase hexagonal crystal system with a (002) interplanar spacing of approximately 0.62 nm, forming a good geometric match with the LDH interlayer spacing. During this stage, the generated MoS2 nanosheets continue to grow, increasing in size, and gradually spreading on the LDH surface to form a continuous covering layer. The high temperature and high pressure conditions of the hydrothermal environment promote the repair of MoS2 lattice defects, improving the crystallinity and chemical stability of the material. After the reaction is completed, unreacted molybdenum and sulfur sources are removed by centrifugation, and free byproducts are removed by washing. Finally, the MoS2-MgAl-LDH heterojunction composite material is obtained by vacuum drying. In this heterojunction structure, a tight heterojunction interface is formed between MoS2 and LDH, which retains the sulfur vacancy active centers of MoS2 and the oxygen vacancy and ion exchange sites of LDH. Furthermore, the electronic structure coupling between the two phases is achieved through interfacial electronic interactions, providing an ideal chemical environment for the formation of Fe-S-Mo bonds and Fe-O-Al(Mg) hydroxyl bonds during the subsequent ball milling bonding process.

[0033] S3, ball mill bonding:

[0034] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.2-1, and sodium thiosulfate was added. The mass ratio of sodium thiosulfate to the mixed powder was 0.05-0.4:1. The mixture was placed in a ball mill jar and milled with zirconia grinding beads with a diameter of 3-10 mm at a ball-to-powder ratio of 10-30:1 at a speed of 200-500 rpm for 4-10 h under argon or nitrogen protection. The mixture was then washed with deoxygenated deionized water and anhydrous ethanol alternately 3-5 times and vacuum dried for 12-24 h to obtain the ball-milled modified composite material.

[0035] The ball milling-induced multi-electrode bonding process consists of four consecutive stages:

[0036] First stage: Mechanical activation: The high-frequency collisions generated by ball milling cause the MoS2 interlayers to peel off, exposing a large number of edge active sites. Lattice defects and unsaturated coordination sites are generated on the FeS surface, and the sodium thiosulfate crystal structure is destroyed. The inert atmosphere protects the fresh surface from oxidation and passivation. The ball milling intensity (200-500 rpm) and ball-to-material ratio (10-30:1) need to be properly controlled. If the intensity is too low, the activation will be insufficient, and if it is too high, it may damage the material structure.

[0037] Phase Two: Generation of Active Sulfur Species and Introduction of Sulfur Vacancies: Mechanical force decomposes sodium thiosulfate to generate active sulfur atoms (S) and sulfide ions (S₂). 2-These active species adsorb onto the surfaces of MoS2 and FeS. At the same time, sodium thiosulfate extracts some sulfur atoms from the MoS2 lattice, forming sulfur vacancies in the lattice. Sulfur vacancies serve as electron enrichment centers, providing key active sites for subsequent permanganate activation. The degree of decomposition of sodium thiosulfate is related to the ball milling time, and 4-10 hours is sufficient for complete decomposition.

[0038] The third stage: Simultaneous construction of double bonds: The active sulfur atoms react simultaneously with the molybdenum atoms at the edge of MoS2 and the iron atoms in FeS to form Fe-S-Mo covalent bonds, connecting FeS and MoS2 at the atomic scale and providing a continuous channel for electron transfer. At the same time, the iron atoms in FeS undergo coordination reactions with Al-OH / Mg-OH on the LDH surface to form Fe-O-Al(Mg) hydroxyl bonds, firmly anchoring the iron species to the LDH surface. The two types of bonding occur simultaneously and promote each other, jointly constructing a stable ternary bonding system.

[0039] Fourth stage: Formation and stabilization of continuous bonding network: The formed Fe-S-Mo bonds and Fe-O-Al(Mg) bonds are gradually connected through sulfur and oxygen atoms to form a continuous bonding network across the heterojunction interface from MoS2 through FeS to LDH. After ball milling for 6-8 hours, the bonding tends to be saturated. Soluble byproducts are removed by washing, deoxidation treatment is performed to prevent oxidation, and vacuum drying is used to stabilize the bonding structure. Finally, a ball-milled modified composite material with an interfacial resistance that is more than 50% lower than that of the physically mixed material is obtained.

[0040] The relevant reactions in the above process are as follows:

[0041] (1) Decomposition of sodium thiosulfate:

[0042] Na₂S₂O₃→Na₂SO₃+S

[0043] (2) Surface activation of MoS2 and formation of sulfur vacancies:

[0044] MoS2+S2O3 2- →MoS 2-x (sulfur vacancy) + SO3 2- +S 2-

[0045] (3) Formation of Fe-S-Mo covalent bonds:

[0046] MoS2 + FeS + S → Mo-S-Fe + S 2-

[0047] (4) Formation of Fe-O-Al(Mg) hydroxyl bonds:

[0048] FeS + Al-OH → Fe-O-Al + HS - +H +

[0049] S4. Water treatment applications:

[0050] The ball-milled modified composite material with a mass ratio of 0.5-2:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 3-9, and the reaction was carried out for 10-60 minutes under stirring conditions to remove pollutants.

[0051] In terms of permanganate activation, ball-milled MoS2 is the core active component for generating free radicals. Step S3 (ball-milling bonding) causes a key structural evolution in MoS2: sodium thiosulfate extracts some sulfur atoms from the MoS2 lattice, precisely introducing sulfur vacancies into the lattice, while continuously acquiring electrons from FeS through Fe-S-Mo covalent bonds, creating an electron-rich state on the MoS2 surface. When permanganate is added to the system, the sulfur vacancies act as electron enrichment centers, transferring the enriched single electrons to the adsorbed MnO4. - While generating high-valent manganese intermediates (Mn(VI), Mn(V)), sulfate free radicals are also produced:

[0052] e - (sulfur vacancy) + MnO4 - →Mn(VI)+SO4 - ·+O 2-

[0053] This reaction is the core step in free radical generation. The non-radical activation pathway dominated by the high-valent manganese intermediate (Mn(VI) / Mn(V)) has good resistance to interference from natural organic matter and inorganic anions in water, while the simultaneously generated sulfate radicals (SO4) - • It can further react with water molecules or hydroxide ions to transform into hydroxyl radicals (·OH), forming a free radical oxidation pathway. Simultaneously, FeS continuously replenishes electrons to the sulfur vacancies of MoS2 through Fe-S-Mo covalent bonds, maintaining the electron-rich state of the sulfur vacancies, and through Fe… 2+ / Fe 3+ The redox cycle participates in the activation of permanganate, further promoting the generation of free radicals. The relevant reaction equations are as follows:

[0054] Mn(VI) + MnO4 - →Mn(V)+Mn(VII)

[0055] Mn(V) + H₂O → Mn(VI) + ·OH + H₂ +

[0056] e - +O2→·O2 -

[0057] 2·O2- +2H + →H₂O₂ + O₂

[0058] H2O2+e - →·OH+OH -

[0059] In antibiotic degradation, high-valent manganese intermediates (Mn(VI) / Mn(V)) selectively oxidize electron-rich groups in antibiotic molecules, such as the aniline and isoxazole rings of sulfamethoxazole and the phenolic hydroxyl and dimethylamino groups of tetracycline, through oxygen atom transfer reactions, achieving efficient degradation. Simultaneously, sulfate and hydroxyl radicals non-selectively oxidize antibiotic molecules and their degradation intermediates through electrophilic addition and hydrogen extraction, achieving deep mineralization. Taking sulfamethoxazole (SMX) as an example, liquid chromatography-mass spectrometry analysis showed that more than ten intermediates could be detected during the reaction process, and its degradation pathway mainly includes three routes. The SMX degradation pathway diagram is shown below. Figure 1 As shown: First, in degradation pathway I, SMX loses the amino group from the benzene ring side chain, forming PA=1 (m / z=238). In the presence of free radicals in the system, sulfonamide bond cleavage and isoxazole ring opening cleavage occur, generating PA=2 (m / z=162) and PA=4 (m / z=100). PA=2 further degrades to form PA=3 (m / z=89). Second, in pathway II, the aniline group is oxidized to generate nitroso or nitro derivatives, producing PB=1 (m / z=267) and PB=2 (m / z=283), followed by sulfonamide bond cleavage. The amide bond breaks, generating a sulfonic acid derivative PB=3 (m / z=187). The sulfonic acid group further hydrolyzes and breaks, generating PB=4 (m / z=139) and PB=5 (m / z=78). Thirdly, in pathway III, the sulfonamide bond in SMX breaks directly, generating two small amine molecules PC=1 (m / z=157) and PC=2 (m / z=98). PC=2 further undergoes hydroxylation and ring-opening reactions to generate PC=3 (m / z=114) and PC=4 (m / z=74), ultimately mineralizing into CO2, H2O, and NO3. - and SO4 2- Inorganic small molecules;

[0060] In terms of heavy metal adsorption, the composite material's multiple active sites synergistically adsorb heavy metals such as lead ions through multiple mechanisms. Sulfur atoms at the edge of MoS2 interact with Pb. 2+ Strong coordination bonds (Pb-S) are formed, enabling sulfur coordination complex adsorption; sulfur vacancies in the MoS2 lattice act as Pb... 2+ The anchoring point enhances adsorption stability through a coordination unsaturated environment; the hydroxyl groups on the LDH surface interact with Pb. 2+ Pb-O coordination bonds are formed to achieve oxygen coordination complex adsorption.

[0061] Preferably, the magnesium salt is MgCl2·6H2O or Mg(NO3)2·6H2O, the aluminum salt is AlCl3·6H2O or Al(NO3)3·9H2O, the alkali is NaOH or KOH, and the carbonate is Na2CO3 or K2CO3.

[0062] Preferably, the molybdenum source is sodium molybdate or ammonium molybdate, and the sulfur source is thiourea or thioacetamide.

[0063] Preferably, the antibiotic is one or more of sulfamethoxazole and tetracycline, with sulfamethoxazole being the primary antibiotic; the heavy metal ions are one or more of lead, copper, cadmium, and zinc, with lead ions being the primary heavy metal ions.

[0064] Preferably, the ball-milled modified composite material achieves continuous electron transfer from ferrous sulfide to the MoS2-MgAl-layered bimetallic hydroxide heterostructure through a continuous bonding network across the heterostructure interface composed of Fe-S-Mo bonds and Fe-O-Al(Mg) hydroxyl bonds.

[0065] Compared with the prior art, the beneficial effects of the present invention are:

[0066] 1. This invention employs a sodium thiosulfate-assisted ball milling-induced chemical bonding strategy to construct a continuous electron transport network across the heterojunction interface, synergistically combining Fe-S-Mo covalent bonds and Fe-O-Al(Mg) hydroxyl bonds. This solves the technical challenges of high interfacial electron transport barriers and isolated active sites in traditional physically composite materials. Through the synergistic effect of ball milling mechanical force and sodium thiosulfate chemical action, sulfur vacancies are precisely introduced into the MoS2 lattice as electron enrichment centers. Simultaneously, FeS acts as an electron supply station, continuously supplying electrons to the sulfur vacancies through Fe-S-Mo covalent bonds, resulting in an electron-rich state on the MoS2 surface. This continuous bonding network reduces the interfacial resistance by more than 50% compared to physically mixed materials, achieving efficient electron migration from FeS to MoS2, thereby significantly improving the activation efficiency of permanganate. Experiments show that the activation efficiency of permanganate is 3-5 times higher than that of single MoS2 or single FeS materials.

[0067] 2. This invention constructs a dual-synergistic oxidation system consisting of a non-radical pathway dominated by high-valent manganese intermediates and a radical pathway dominated by sulfate radicals / hydroxyl radicals, solving the problem of single activation pathways being easily interfered with by the water matrix or resulting in incomplete mineralization. Electrons enriched in sulfur vacancies reduce permanganate to high-valent manganese intermediates (Mn(VI) / Mn(V)). This non-radical pathway exhibits good resistance to interference from natural organic matter and inorganic anions in the water. Simultaneously generated sulfate radicals (SO4)... -• and hydroxyl radicals (·OH) achieve deep mineralization of antibiotics through non-selective oxidation. The synergistic effect of the dual pathways enables the removal rate of sulfamethoxazole and tetracycline to reach over 95%, and the total organic carbon removal rate to reach over 65%.

[0068] 3. This invention achieves efficient adsorption of heavy metals through the multi-faceted synergy of sulfur coordination sites and sulfur vacancy anchoring sites in MoS2 and hydroxyl complexation sites on the LDH surface. The sulfur atoms at the edge of MoS2 interact with Pb... 2+ A strong coordination bond (Pb-S) is formed, with sulfur vacancies acting as Pb sites. 2+ The anchoring point provides a coordination unsaturated environment, and the hydroxyl groups on the LDH surface interact with Pb. 2+ The formation of Pb-O coordination bonds, with three mechanisms working synergistically, enables Pb to form Pb-O coordination bonds. 2+ The removal rate reaches over 98%, and iron species are firmly anchored through Fe-S-Mo covalent bonds, with metal ion leaching rate below 0.01 mg / L. After six cycles, the removal rate remains above 85%, demonstrating good cycle stability and environmental friendliness. Attached Figure Description

[0069] Figure 1 This is a diagram of the SMX degradation pathway in this invention;

[0070] Figure 2 The graphs show the changes in SMX removal rate for the examples and comparative examples.

[0071] Figure 3 The graphs show the changes in Pb(II) removal rates for the examples and comparative examples. Detailed Implementation

[0072] The technical solutions of this invention are described below. It should also be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; those skilled in the art can also use other alternative methods to implement some well-known technologies.

[0073] In the following examples and comparative examples, the magnesium salt used in the synthesis step of MgAl-layered bimetallic hydroxide is MgCl2·6H2O, the aluminum salt is AlCl3·6H2O, the base is NaOH, and the carbonate is Na2CO3.

[0074] The molybdenum source used in the hydrothermal composite process is sodium molybdate, and the sulfur source is thiourea.

[0075] Example 1: A method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0076] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0077] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0078] S2, Hydrothermal Composite:

[0079] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0080] S3, ball mill bonding:

[0081] MoS2-MgAl-layered bimetallic hydroxide heterostructure was mixed with ferrous sulfide at a mass ratio of 1:0.2, and sodium thiosulfate was added at a mass ratio of 0.2:1. The mixture was placed in a ball mill jar and milled for 6 hours at 350 rpm under argon or nitrogen protection using 5 mm diameter zirconia grinding beads at a ball-to-powder ratio of 20:1. The mixture was then washed four times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0082] S4. Water treatment applications:

[0083] The ball-milled modified composite material with a mass ratio of 1:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0084] Example 2: Method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0085] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0086] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0087] S2, Hydrothermal Composite:

[0088] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0089] S3, ball mill bonding:

[0090] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.6, and sodium thiosulfate was added at a mass ratio of 0.2:1 to the mixed powder. The mixture was placed in a ball mill jar and milled at 350 rpm for 4 hours under argon or nitrogen protection using 5 mm diameter zirconia grinding beads at a ball-to-powder ratio of 20:1. The mixture was then washed four times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0091] S4. Water treatment applications:

[0092] The ball-milled modified composite material with a mass ratio of 1:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0093] Example 3: Method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0094] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0095] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0096] S2, Hydrothermal Composite:

[0097] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0098] S3, ball mill bonding:

[0099] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.6, and sodium thiosulfate was added. The mass ratio of sodium thiosulfate to the mixed powder was 0.05:1. The mixture was placed in a ball mill jar and milled for 6 hours at 350 rpm under argon or nitrogen protection using 5 mm diameter zirconia grinding beads at a ball-to-powder ratio of 20:1. The mixture was then washed 4 times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0100] S4. Water treatment applications:

[0101] The ball-milled modified composite material with a mass ratio of 1:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0102] Example 4: Method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0103] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0104] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0105] S2, Hydrothermal Composite:

[0106] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0107] S3, ball mill bonding:

[0108] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.6, and sodium thiosulfate was added at a mass ratio of 0.2:1 to the mixed powder. The mixture was placed in a ball mill jar and milled for 6 hours at 350 rpm under argon or nitrogen protection using zirconia ball milling beads with a diameter of 5 mm and a ball-to-powder ratio of 20:1. The mixture was then washed 4 times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0109] S4. Water treatment applications:

[0110] The ball-milled modified composite material with a mass ratio of 0.5:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0111] Example 5: A method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0112] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0113] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0114] S2, Hydrothermal Composite:

[0115] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0116] S3, ball mill bonding:

[0117] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.6, and sodium thiosulfate was added at a mass ratio of 0.2:1 to the mixed powder. The mixture was placed in a ball mill jar and milled for 6 hours at 350 rpm under argon or nitrogen protection using zirconia ball milling beads with a diameter of 5 mm and a ball-to-powder ratio of 20:1. The mixture was then washed 4 times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0118] S4. Water treatment applications:

[0119] The ball-milled modified composite material with a mass ratio of 2:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0120] Example 6: A method for removing antibiotics from MoS2-activated permanganate by ball milling:

[0121] Synthesis of S1, MgAl-layered bimetallic hydroxide:

[0122] Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 3:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. The pH was controlled at 9.5-10.5. The solution was crystallized at 70°C for 18 hours. After centrifugation, washing, and drying, MgAl-layered bimetallic hydroxide was obtained.

[0123] S2, Hydrothermal Composite:

[0124] MgAl-layered bimetallic hydroxide was dispersed in water at a concentration of 10 g / L. A molar ratio of molybdenum source and sulfur source was added at 1:4, and the mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 7.5:1. The mixture was ultrasonically dispersed for 40 min, transferred to a high-pressure reactor, and hydrothermally reacted at 200℃ for 18 h. After centrifugation, washing, and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained.

[0125] S3, ball mill bonding:

[0126] MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.6, and sodium thiosulfate was added at a mass ratio of 0.2:1 to the mixed powder. The mixture was placed in a ball mill jar and milled for 6 hours at 350 rpm under argon or nitrogen protection using zirconia ball milling beads with a diameter of 5 mm and a ball-to-powder ratio of 20:1. The mixture was then washed 4 times with deoxygenated deionized water and anhydrous ethanol, and vacuum dried for 24 hours to obtain the ball-milled modified composite material.

[0127] S4. Water treatment applications:

[0128] The ball-milled modified composite material with a mass ratio of 1:1 was added together with sodium permanganate to the water to be treated containing antibiotics and heavy metals. The reaction pH was 6, and the reaction was carried out for 30 minutes under stirring conditions to remove pollutants.

[0129] Comparative Example 1:

[0130] Compared with Example 6, Comparative Example 1 used raw MoS2 without the S1-S3 treatment, and other conditions remained unchanged.

[0131] Comparative Example 2:

[0132] Compared with Example 6, FeS was not added in Step 3 of Comparative Example 2, while other conditions remained unchanged.

[0133] Comparative Example 3:

[0134] Compared with Example 6, in Comparative Example 3, MoS2-MgAl-layered bimetallic hydroxide heterojunctions were not synthesized; instead, MoS2 and Na2S2O3 were directly ball-milled, with other conditions remaining unchanged.

[0135] Comparative Example 4:

[0136] Compared with Example 6, in Comparative Example 4, the MoS2-MgAl-layered bimetallic hydroxide heterojunction was physically mixed with FeS without the ball milling bonding in step S3, and other conditions remained unchanged.

[0137] Comparative Example 5:

[0138] Compared with Example 6, Comparative Example 5 did not add permanganate, while other conditions remained unchanged.

[0139] Comparative Example 6:

[0140] Compared with Example 6, Comparative Example 6 did not include ball milling modified composite material, while other conditions remained unchanged.

[0141] Performance testing:

[0142] National standard testing: The concentration of antibiotics in the treated water body should be determined according to the "Determination of Sulfonamide Antibiotics in Water - High Performance Liquid Chromatography" (HJ 1024-2019) to determine the sulfamethoxazole content before and after the reaction, and according to the "Determination of Tetracycline Antibiotics in Water - High Performance Liquid Chromatography" (HJ 1268-2022) to determine the tetracycline content before and after the reaction; the concentration of lead, copper, cadmium, and zinc heavy metal ions in the water before and after the reaction should be tested according to the "Determination of Copper, Zinc, Lead, and Cadmium in Water - Atomic Absorption Spectrophotometry" (GB / T 7475-1987). To verify the mineralization effect of pollutants, chemical oxygen demand (COD) needs to be determined according to the "Determination of Chemical Oxygen Demand in Water - Dichromate Method" (HJ 828-2017), and total organic carbon (TOC) needs to be determined according to the "Determination of Total Organic Carbon in Water - Combustion Oxidation - Non-dispersive Infrared Absorption Method" (HJ 501-2009). The leaching concentrations of molybdenum, iron, aluminum, and magnesium in the post-reaction water sample need to be determined according to the "Determination of Metal Elements in Water - Inductively Coupled Plasma Mass Spectrometry" (HJ 700-2014) to assess the chemical stability and secondary pollution risk of the ball-milled modified composite material. The treated effluent needs to meet the requirements of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002). If reclaimed water reuse is involved, it also needs to meet the relevant limit requirements of the "Environmental Quality Standard for Surface Water" (GB3838-2002) and the "Groundwater Quality Standard" (GB / T 14848-2017).

[0143] Required tests include: determining the residual permanganate in water using redox titration, with titration using sodium oxalate standard solution and back titration using potassium permanganate to complete the detection and concentration calculation; calculating the antibiotic removal rate and heavy metal removal rate using the formula: Removal rate (%) = (Initial concentration - Post-treatment concentration) / Initial concentration × 100%; and testing the material's stability through six cycles of centrifugation, washing, and reuse to verify the pollutant removal effect after continuous use (expressed as the stability of sulfamethoxazole and lead ion removal rates).

[0144] The test results of the above embodiments and comparative examples are shown in Tables 1, 2, 3 and 4 below.

[0145] Table 1. Antibiotic and heavy metal removal data from different embodiments and comparative examples.

[0146] Data Analysis:

[0147] Example 1: This example uses a MoS2-LDH to FeS mass ratio of 1:0.2 and ball milling for 6 hours. Compared with Example 6, due to the lower FeS ratio, the electron supply capacity of sulfur vacancies is limited, resulting in moderate antibiotic degradation efficiency and mineralization degree. Regarding heavy metal adsorption, because the adsorption sites of MoS2 and LDH are still fully exposed, the removal effect of lead ions is similar to that of Example 6. In the above examples, the Zn(II) removal rate is lower than that of Pb(II), which is related to its weaker sulfur affinity (soft and hard acid-base theory) and smaller ionic radius, which is unfavorable for sulfur vacancy anchoring.

[0148] Example 2: In this example, the ball milling time was shortened to 4 hours. Compared to the example with 6 hours of ball milling, the shorter milling time resulted in insufficient exfoliation of the MoS2 layers, a lower degree of Fe-S-Mo chemical bonding, and suboptimal interfacial electron transfer efficiency. Consequently, both antibiotic removal rate and mineralization index decreased. Heavy metal adsorption performance was also affected, but the decrease was less than that of antibiotic degradation, indicating that the adsorption function is less sensitive to ball milling time than the catalytic activation function.

[0149] Example 3: In this example, the sodium thiosulfate addition was reduced to 0.05:1. Insufficient sodium thiosulfate resulted in inadequate introduction of sulfur vacancies into the MoS2 lattice, a decrease in the number of electron enrichment centers, and a reduction in permanganate activation efficiency. The antibiotic degradation and mineralization effects were the lowest among the six examples. Heavy metal adsorption performance was also somewhat affected, but the removal of lead ions remained relatively high, indicating that the contribution of sulfur vacancies to heavy metal adsorption was less than their contribution to antibiotic degradation.

[0150] Example 4: In this example, the mass ratio of the composite material to potassium permanganate was adjusted to 0.5:1. With a relative excess of permanganate, the antibiotic degradation reaction was more complete, but due to the relatively insufficient active sites on the catalyst, the overall removal efficiency was slightly lower than the optimal ratio. Notably, heavy metal adsorption was almost unaffected, indicating that the adsorption process mainly depends on the material's own structure rather than the oxidant.

[0151] Example 5: In this example, the mass ratio of the composite material to potassium permanganate was adjusted to 2:1. With a relative excess of catalyst, the antibiotic degradation efficiency was further improved, but the relative deficiency of permanganate limited the full generation of free radicals, and the overall effect was still slightly inferior to the optimal ratio. Heavy metal adsorption was among the best in the six examples, with the excess catalyst providing more adsorption sites.

[0152] Example 6: This example represents the optimal preparation and application conditions, namely, a FeS ratio of 1:0.6, ball milling for 6 hours, a sodium thiosulfate ratio of 0.2:1, and a composite material to potassium permanganate mass ratio of 1:1. Under these conditions, the continuous electron transport network across the heterojunction interface formed by the Fe-S-Mo covalent bonds and Fe-O-Al hydroxyl bonds is most complete, the sulfur vacancy density and electron enrichment capacity are optimal, and the permanganate activation efficiency is the highest. Therefore, the antibiotic degradation rate, mineralization degree, and heavy metal adsorption effect are all superior to all other examples.

[0153] Comparative Example 1: This comparative example uses unmodified raw MoS2. Due to the lack of ball milling exfoliation, sulfur vacancy introduction, and LDH composite, the material has a small specific surface area, few active sites, and no chemical bonding network to provide electron transfer channels. Antibiotic degradation relies solely on the limited adsorption capacity of raw MoS2, and the heavy metal removal effect is far lower than that of the modified composite material.

[0154] Comparative Example 2: FeS was not added during the ball milling process in this comparative example. Without FeS, Fe-S-Mo covalent bonds could not form, the continuous supply of electrons from iron species to sulfur vacancies was interrupted, and the sulfur vacancies struggled to maintain an electron-rich state. This resulted in a significant decrease in permanganate activation efficiency and a lower antibiotic degradation effect compared to the iron-containing example. Heavy metal adsorption performance was also weakened because the absence of sulfur sites on the FeS surface reduced the sulfur coordination adsorption capacity.

[0155] Comparative Example 3: This comparative example only involved direct ball milling of MoS2 with sodium thiosulfate. Without LDH, the material lost the oxygen vacancies, hydroxyl bonding sites, and interlayer ion exchange capacity provided by LDH. MoS2 was prone to excessive stacking during ball milling, resulting in poor dispersion of active sites. The antibiotic degradation and heavy metal adsorption effects were significantly lower than in the LDH-containing example, demonstrating that LDH is indispensable as a structural building block.

[0156] Comparative Example 4: This comparative example physically mixes MoS2-LDH and FeS without ball milling for bonding. In physical mixing, FeS and MoS2-LDH only form physical contact, lacking a continuous electron transport channel built by Fe-S-Mo covalent bonds. This results in high interfacial resistance and poor electron transport efficiency. Furthermore, the iron species are not chemically anchored and are easily lost during the reaction. Therefore, the antibiotic degradation effect is far lower than in the ball-milled bonding example, demonstrating that chemical bonding is superior to physical mixing.

[0157] Comparative Example 5: This comparative example did not add permanganate and only used ball-milled modified composite materials. Therefore, antibiotic removal mainly relied on the adsorption of the material and free radical oxidation driven by multiple electron sources. Specifically, Fe in FeS 2+ Electrons are continuously supplied to the sulfur vacancies in MoS2 through Fe-S-Mo covalent bonds. Simultaneously, MoS2, as a narrow-bandgap semiconductor, is excited to generate photogenerated electron-hole pairs. These photogenerated electrons react with dissolved oxygen to produce superoxide radicals (·O2). - Photogenerated holes react with surface hydroxyl groups to generate hydroxyl radicals (·OH), contributing to the oxidative degradation capacity. Therefore, the antibiotic removal rate is higher than that of pure physical adsorption. Heavy metal ions are efficiently adsorbed through multiple mechanisms such as sulfur coordination, sulfur vacancy anchoring, and LDH hydroxyl complexation, with removal effects close to those in Example 6, demonstrating that the composite material itself has excellent heavy metal adsorption capacity.

[0158] Comparative Example 6: This comparative example did not add the composite material and only used permanganate. The direct oxidation capacity of permanganate in its unactivated state was limited, resulting in the lowest antibiotic removal effect among all groups. Simultaneously, permanganate showed almost no removal capacity for heavy metal ions, leading to extremely high heavy metal residue rates, and the antibiotic removal rate was even lower than in Comparative Example 5. This indicates that the adsorption and self-driven oxidation contribution of the composite material is superior to the direct oxidation of unactivated permanganate, and that using permanganate alone cannot achieve the treatment of combined antibiotic and heavy metal pollution.

[0159] Table 2 Cyclic stability of different embodiments and comparative examples (SMX removal rate, in %)

[0160] Table 3 Cyclic stability (Pb(II) removal rate, in %) of different embodiments and comparative examples

[0161] Note: Since the first Pb(II) removal rate in Comparative Example 6 was only 8.6%, no subsequent stability test was conducted on it.

[0162] Data Analysis:

[0163] From the data in Tables 2 and 3, and Figure 2 , Figure 3 It can be seen that the removal rates of SMX and Pb(II) in all examples and comparative examples showed a gradual decreasing trend during six cycles, but the magnitude of the decrease differed significantly. Example 6 achieved the best performance among all groups, with SMX and Pb(II) removal rates of 88.3% and 93.2% respectively after six cycles. This is attributed to the effective anchoring of the active components by the continuous bonding network across the heterojunction interface constructed by Fe-S-Mo covalent bonds and Fe-O-Al hydroxyl bonds, preventing the loss of iron species and the degradation of active sites. Comparing Examples 1 and 2, it can be seen that extending the ball milling time from 4 h to 6 h significantly improved cycle stability, while the insufficient sodium thiosulfate dosage in Example 3 led to a significant decrease in retention rate, indicating that sufficient sulfur vacancy introduction is crucial for maintaining long-term catalytic activity.

[0164] All groups showed higher Pb(II) retention rates than SMX retention rates. For example, the Pb(II) retention rate (93.2%) in Example 6 was about 5% higher than the SMX retention rate (88.3%), and Comparative Example 5 also showed a higher Pb(II) retention rate (80.5%) than the SMX retention rate (49.2%). This indicates that heavy metal adsorption mainly relies on the structural characteristics of the material itself, such as sulfur coordination sites, sulfur vacancies, and LDH hydroxyl groups. These adsorption sites are relatively stable during recycling. In contrast, antibiotic degradation relies on active species generated by permanganate activation, and the catalytically active sites are more susceptible to degradation due to factors such as intermediate product accumulation and surface contamination.

[0165] The difference in stability between chemical bonding and physical mixing is particularly evident in the comparison between Comparative Example 4 and Example 6. Comparative Example 4, using physical mixing, showed an SMX retention rate of only 61.1% after six cycles, while Example 6 achieved a retention rate as high as 88.3%, a difference of nearly 27%. This demonstrates that ball milling-induced chemical bonding plays a decisive role in improving the cycling stability of the material. Comparative Example 2, lacking FeS, achieved an SMX retention rate of 61.6%, similar to the 61.1% of Comparative Example 4, indicating that the absence of FeS, like physical mixing, leads to a significant decrease in stability. Comparative Example 3, without synthesized heterojunction, achieved a retention rate of 63.8%, slightly higher than the previous two but still far lower than the examples, indicating that the structural support and oxygen vacancies provided by LDH also contribute to maintaining stability.

[0166] It is noteworthy that Comparative Example 5, using only the composite material without permanganate, achieved a Pb(II) retention rate as high as 80.5%, demonstrating superior heavy metal adsorption stability compared to Comparative Examples 2, 3, and 4, and even approaching the levels of some examples. This further confirms the excellent stability of the composite material's adsorption structure itself. However, its SMX retention rate was only 49.2%, decreasing from 35.6% to 17.5% after six cycles. This is because, lacking permanganate activation, it primarily relies on adsorption and a small amount of self-driven oxidation; once the active sites are occupied, regeneration is difficult. Comparative Example 6, using only permanganate without the composite material, exhibited the lowest retention rates for both SMX and Pb(II), indicating that the system has almost no recycling value without a catalyst.

[0167] Table 4. Metal ion leaching concentration data of different embodiments and comparative examples

[0168] Note: "—" indicates that the metal element is not present in the sample and does not need to be detected.

[0169] The data in Table 4 above show that, under optimal preparation conditions, Example 6, through a continuous bonding network across the heterojunction interface constructed by Fe-S-Mo covalent bonds and Fe-O-Al hydroxyl bonds, firmly anchored iron species in the composite material, while maintaining the integrity of the LDH layer structure. Therefore, the leaching concentrations of Fe, Al, and Mg were all below the detection limit (<0.01 mg / L), significantly better than Comparative Example 4, which used physical mixing (Fe leaching 0.25 mg / L, Al leaching 0.08 mg / L, Mg leaching 0.05 mg / L), demonstrating that chemical bonding effectively prevented the loss of active components. In Examples 1-3, the Fe leaching concentration (0.08-0.15 mg / L) increased with decreasing sodium thiosulfate dosage and shortened ball milling time, indicating that insufficient sulfur vacancy introduction and inadequate bonding weaken the anchoring effect of iron species. Although Comparative Example 5 did not add permanganate, the composite material itself had an intact structure, and the metal leaching was also extremely low, further confirming that chemical bonding is key to reducing metal loss. Mo leaching in all groups was below the detection limit, indicating that the MoS2 lattice structure remained stable during ball milling modification. Comparative Example 6 used only permanganate, and no molybdenum, iron, aluminum, or magnesium elements were leached, so no detection was required.

[0170] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for removing antibiotics from MoS2-activated permanganate by ball milling, characterized in that, Includes the following steps: Synthesis of S1, MgAl-layered bimetallic hydroxide: Magnesium salt and aluminum salt were dissolved in water at a molar ratio of 2-4:1 and added dropwise to a solution containing alkali and carbonate under an inert atmosphere. After crystallization for 12-24 hours, the solution was centrifuged, washed, and dried to obtain MgAl-layered bimetallic hydroxide. S2, Hydrothermal Composite: MgAl-layered bimetallic hydroxide was dispersed in water, and a molar ratio of molybdenum source and sulfur source was added. The mass ratio of MgAl-layered bimetallic hydroxide to molybdenum source was 5-10:

1. The mixture was ultrasonically dispersed and transferred to a high-pressure reactor for hydrothermal reaction. After centrifugation, washing and drying, MoS2-MgAl-layered bimetallic hydroxide heterojunction was obtained. S3, ball mill bonding: MoS2-MgAl-layered bimetallic hydroxide heterojunction was mixed with ferrous sulfide at a mass ratio of 1:0.2-1 to obtain a mixed powder. Sodium thiosulfate was added and ball-milled together. The mass ratio of sodium thiosulfate to the mixed powder was 0.05-0.4:

1. The relevant process parameters for ball milling were as follows: using zirconia ball milling beads with a diameter of 3-10 mm, the ball-to-material ratio was 10-30:1, and the process was carried out under argon or nitrogen protection at a speed of 200-500 rpm. The mixture was washed alternately with deoxygenated deionized water and anhydrous ethanol, and then vacuum dried to obtain the ball-milled modified composite material. The ball-milled modified composite material achieves continuous electron transfer from ferrous sulfide to the MoS2-MgAl-layered bimetallic hydroxide heterostructure through a continuous bonding network across the heterostructure interface composed of Fe-S-Mo bonds and Fe-O-Al(Mg) hydroxyl bonds. S4. Water treatment applications: The ball-milled modified composite material and permanganate were added together to the water to be treated containing antibiotics and heavy metals, and the reaction was carried out under stirring conditions to remove pollutants.

2. The method for removing antibiotics from MoS2-activated permanganate by ball milling according to claim 1, characterized in that, The magnesium salt in S1 is MgCl2·6H2O or Mg(NO3)2·6H2O, the aluminum salt is AlCl3·6H2O or Al(NO3)3·9H2O, the alkali is NaOH or KOH, and the carbonate is Na2CO3 or K2CO3; the crystallization temperature is 60-80℃, and the pH is 9.5-10.

5.

3. The method for removing antibiotics from MoS2-activated permanganate by ball milling according to claim 1, characterized in that, The concentration of the MgAl-layered bimetallic hydroxide dispersed in water in S2 is 5-20 g / L, and the ultrasonic dispersion time is 20-60 min; the molybdenum source is sodium molybdate or ammonium molybdate, and the sulfur source is thiourea or thioacetamide.

4. The method for removing antibiotics from MoS2-activated permanganate by ball milling according to claim 1, characterized in that, The antibiotics mentioned in S4 are one or more of sulfamethoxazole and tetracycline; the heavy metal ions in the water to be treated are one or more of lead, copper, cadmium, and zinc.

5. The method for removing antibiotics from MoS2-activated permanganate by ball milling according to claim 1, characterized in that, The permanganate mentioned in S4 is potassium permanganate or sodium permanganate. The mass ratio of the ball-milled modified composite material to the permanganate is 0.5-2:1, the reaction time is 10-60 min, and the reaction pH is 3-9.

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