Preparation method and application of biochar composite material

Abstract

The present invention provides a preparation method and application of a biochar composite material, which relates to the field of water treatment technology, and comprises the following steps: S1, hydrothermal biochar preparation: mixing pine needle powder with distilled water, performing a hydrothermal reaction, and obtaining hydrothermal biochar; S2, porous biochar preparation: mixing the hydrothermal biochar and KHCO₃ in a weight ratio of 1:4, ball milling, and heating to obtain porous biochar; S3, Fe3Co@BC synthesis: immersing C800 in a Co / Fe nitrate ethanol solution, reacting to generate an Fe3Co alloy, and simultaneously loading the Fe3Co alloy on the C800, i.e., Fe3Co@BC; the present invention selects pine needles from agricultural and forestry waste to construct a carbon layer structure with a large number of pores, and loads the Fe3Co alloy to enhance the catalytic activity of PMS, thereby constructing for the first time a pine needle-derived biochar-loaded Fe3Co alloy catalyst with high catalytic performance, i.e., a biochar composite material (Fe3Co@BC).

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a preparation method and application of a biochar composite material. Background Art

[0002] With the advancement of industrialization, industrial wastewater discharge is increasing. The widespread demand and use of BPA (bisphenol A) leads to its continuous release into water bodies through various channels, including industrial wastewater discharge, landfill leachate leakage, and leaching from waste materials. As an endocrine disruptor, BPA release can harm human and other biological health even at low exposure levels. Research on the removal of BPA from aquatic environments is essential, but BPA's symmetrical double benzene ring structure dictates its high stability in aqueous solutions, placing higher demands on advanced water treatment processes.

[0003] Existing technologies for removing BPA from industrial wastewater primarily rely on traditional water treatment processes, such as coagulation-sedimentation and filtration. However, with increasingly stringent environmental protection requirements and the increasing complexity of industrial wastewater composition, these processes are no longer able to meet the demand for efficient and environmentally friendly treatment. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for preparing a biochar composite material, comprising the following steps:

[0005] S1. Hydrothermal biochar preparation: Pine needle powder was mixed with distilled water and subjected to hydrothermal reaction at 180°C for 12 hours to obtain hydrothermal biochar (HB);

[0006] S2. Preparation of porous biochar: Hydrothermal biochar (HB) and KHCO3 were mixed in a weight ratio of 1:3-5 (preferably 1:4), ball-milled for 30 minutes, and then heated to 800°C at a heating rate of 5°C / min under nitrogen atmosphere and held for 2 hours to obtain porous biochar (C800).

[0007] S3. Synthesis of Fe3Co@BC: C800 was immersed in a Co / Fe nitrate ethanol solution, dried, and then pyrolyzed for 2 hours to generate Fe3Co alloy which was simultaneously loaded on C800, namely Fe3Co@BC.

[0008] Furthermore, the Co / Fe nitrate ethanol solution is an ethanol solution containing Co(NO3)2·6H2O and Fe(NO3)3·9H2O in a ratio of 1:3 (molar ratio).

[0009] Furthermore, the mass ratio of the Fe3Co alloy to the porous biochar (C800) is 1:2.

[0010] Furthermore, in step S3, after drying, the mixture is heated to 700° C. at a heating rate of 5° C. / min in a nitrogen atmosphere and pyrolyzed for 2 hours.

[0011] Furthermore, the specific surface area of the Fe3Co@BC is 1218.08 m² / g, the average pore size is 7.34 nm, and the Fe3Co alloy particles are uniformly loaded on the porous biochar.

[0012] In another aspect, the present invention provides an application of a method for preparing a biochar composite material.

[0013] Furthermore, the application method is as follows:

[0014] Step 1: adding Fe3Co@BC and peroxymonosulfate to water containing organic pollutants, wherein the dosage of Fe3Co@BC is 0.2 g / L and the dosage of peroxymonosulfate is 0.2 g / L;

[0015] Step 2: react at 25°C for 5 minutes.

[0016] Furthermore, the organic pollutants include BPA (bisphenol A), basic blue, malachite green, tetracycline hydrochloride, and oxytetracycline hydrochloride.

[0017] Furthermore, the organic pollutant is BPA, and the degradation rate of BPA within 5 minutes is more than 99%. After 8 hours of dynamic circulation, the removal rate of bisphenol A (BPA) is still higher than 87%.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention uses advanced oxidation processes (AOPs) to treat organic pollutants. This method can completely mineralize or decompose most organic matter. Compared with hydroxyl radicals and superoxide radicals, sulfate radicals generated by activated peroxymonosulfate (PMS) have a stronger redox potential and can be applied to more complex organic pollutant degradation systems. FeCo alloys as AOP catalysts driving PMS still have broad research prospects. The large specific surface area and high porosity of biomass carbon are conducive to the adsorption of PMS and pollutants. At the same time, it can achieve uniform metal loading and high dispersion of active species.

[0020] 2. The present invention uses pine needles, a waste product of agricultural and forestry, to construct a carbon layer structure with a large number of pores and loads Fe3Co alloy to enhance the catalytic activity of PMS. This is the first time that a pine needle-derived biochar-loaded Fe3Co alloy catalyst with high catalytic performance, namely a biochar composite material (Fe3Co@BC), has been constructed. For the first time, the Fe3Co@BC catalyst has been used to activate PMS to achieve ultra-high BPA degradation efficiency in a short time.

[0021] 3. This invention is the first to construct a pine needle-derived biochar-loaded Fe3Co alloy catalyst (0.5Fe3Co@BC). The Fe3Co alloy loading optimizes charge distribution, resulting in highly efficient catalytic performance for 0.5Fe3Co@BC, ultimately achieving an ultra-high degradation rate of 99.36% in 5 minutes. EPR and electrochemical experiments confirmed that the Fe3Co alloy loading improved electron transfer efficiency, thereby enhancing the ability to activate PMS and the degradation efficiency of BPA. The BPA removal rate remained above 87% during 8 hours of dynamic cycling. Furthermore, 0.5Fe3Co@BC also exhibited good degradation performance for antibiotics and dyes. The catalytic degradation of BPA is a process involving the combined action of free radicals and non-free radicals. O2• − It plays a leading role in the degradation of bisphenol A.

[0022] 4. The present invention uses biomass waste pine needles as carbon source and constructs a loose porous carbon layer (C800) structure through KHCO3 activation, with a carbon content of 1616.9 m 2 g −1 The high specific surface area provides conditions for the high dispersion of Fe3Co alloy and the rapid adsorption and in-situ degradation of BPA. The present invention is of particular significance to the development and utilization of waste biomass resources and environmental governance, and is in line with the concept of green sustainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a summary of the experimental results of BPA degradation efficiency under different conditions; Figure 1 a is the BPA removal efficiency of different systems within 5 minutes; 1b is the initial concentration of BPA, 1c is the PMS dosage, 1d is the catalyst dosage, 1e is the pH value, and 1f is the effect of temperature on BPA degradation efficiency.

[0024] Figure 2 The pseudo-first-order kinetic equation for the degradation of BPA by PMS activated by different materials.

[0025] Figure 3 is the pseudo-first-order kinetic constant k for BPA degradation at different temperatures.

[0026] Figure 4 The key experimental data diagram for the adsorption and quantitative analysis of BPA; Figure 4 a is the standard curve of BPA solution; 4b is the adsorption isotherm of 0.5Fe3Co@BC.

[0027] Figure 5 Thermodynamic behavior of BPA adsorption on 0.5Fe3Co@BC; Figure 5 a shows the effect of temperature on the adsorption of BPA by 0.5Fe3Co@BC, and 5b shows the thermodynamic fitting curve of 0.5Fe3Co@BC.

[0028] Figure 6 is the micromorphology and structural characterization of 0.5Fe3Co@BC catalyst; 6a and 6b are SEM images of 0.5Fe3Co@BC; 6c is the TEM image of 0.5Fe3Co@BC; 6d is the HRTEM image of 0.5Fe3Co@BC; 6e is the SAED pattern of 0.5Fe3Co@BC; 6f is the EDS image of 0.5Fe3Co@BC.

[0029] Figure 7 A comprehensive representation diagram of the phase structure, chemical bond and pore characteristics of different samples; Figure 7 a is the XRD image of different samples, 7b is the Raman image of different samples, 7c is the N2 adsorption-desorption diagram and pore size distribution of HB, 7d is the N2 adsorption-desorption diagram and pore size distribution of C800; 7e is the N2 adsorption-desorption diagram and pore size distribution of 0.5Fe3Co@BC.

[0030] Figure 8 is the pseudo-first-order kinetic constant k for BPA degradation after adding different anions and HA.

[0031] Figure 9 To evaluate the comprehensive performance of 0.5Fe3Co@BC materials in practical environmental applications; Figure 9 a shows the effect of different inorganic ions and hyaluronic acid on BPA degradation; 9b shows the reusability of 0.5Fe3Co@BC; 9c shows the degradation efficiency of BPA in different environments; 9d shows the removal efficiency of 0.5Fe3Co@BC for antibiotics and dyes.

[0032] Figure 10 It is a dynamic circulation device.

[0033] Figure 11 0.5Fe3Co@BC+PMS degrades other organic pollutants; 11a is basic blue, 11b is malachite green, 11c is tetracycline hydrochloride, and 11d is oxytetracycline hydrochloride.

[0034] Figure 12 This is the SEM image of 0.5Fe3Co@BC after use.

[0035] Figure 13 XRD patterns of 0.5Fe3Co@BC before and after use.

[0036] Figure 14 To identify and study the mechanism of action of active free radicals in the degradation of BPA by 0.5Fe3Co@BC / PMS system; Figure 14a shows the effect of different free radical scavengers on the degradation efficiency of BPA; 14b is the EPR spectrum of •OH and SO4•⁻ captured by DMPO; 14c is the EPR spectrum of O2•⁻ captured by DMPO; 14d is the EPR spectrum of ¹O2 captured by TEMP.

[0037] Figure 15 The test results for the electrochemical performance and composition analysis of 0.5Fe3Co@BC composite materials; Figure 15 a is the CV diagram of the catalyst; 15b is the electrochemical impedance spectra of different materials; 15c is the XPS total spectrum of 0.5Fe3Co@BC before and after use; 15d is the high-resolution XPS spectrum of Co 2p and the change in valence state ratio before and after use; 15e is the high-resolution XPS spectrum of Fe 2p and the change in valence state ratio before and after use.

[0038] Figure 16 These are the possible degradation pathways and intermediates of BPA.

[0039] Figure 17 is the TOC removal rate. DETAILED DESCRIPTION

[0040] Example 1 Preparation of super-loose carbon material (C800)

[0041] 5.00 g of pine needle powder and 50 ml of distilled water were placed in a polytetrafluoroethylene reactor and reacted at 180 °C for 12 hours to obtain hydrothermal biochar (HB), which was then dried in an 80 °C oven to constant weight. HB and KHCO3 were mixed in a weight ratio of 1:4 and then ball-milled for 30 minutes. The mixture was heated in a tube furnace at 800 °C under nitrogen for 2 hours at a heating rate of 5 °C min -1 After grinding in an agate mortar, the sample was rinsed with 1 M KOH for 1 hour and then with 2 M HCl for 1 hour. Finally, it was filtered and dried in a vacuum oven at 80 °C for 24 hours to produce porous biochar, denoted as C800.

[0042] Example 2 Preparation of Fe3Co alloy catalyst supported on porous carbon layer (0.5Fe3Co@BC)

[0043] 0.058 g Co(NO3)2∙6H2O and 0.240 g Fe(NO3)3∙9H2O were dissolved in 10 mL of ethanol to form a metal nitrate mixture. C800 was added to 35 mL of ethanol and dispersed under ultrasonic conditions for 30 min to form a homogeneous solution. Next, the metal nitrate mixture was slowly added to the C800 suspension under magnetic stirring at 80 °C and heated for 1 hour to evaporate the ethanol. The obtained solid was dried in a vacuum oven at 80 °C for 4 hours. Subsequently, the obtained solid mixture was heated in a tube furnace at 5 °C min in a N2 atmosphere. -1 The pyrolysis was carried out at 700°C for 2 h at a heating rate of 1.5 ℃. The prepared material is designated as Fe3Co@BC. Using the same synthesis method, a series of materials with different loading ratios were prepared by adjusting the amount of added pine needle biochar. The mass ratios of the total mass of cobalt and iron to C800 were 2:1, 1:1, and 1:2, respectively, namely, 0.298 g of Co(NO3)2·6H2O, Fe(NO3)3·9H2O (molar ratio of 1:3) and 0.149 g of C800, 0.149 g of Co(NO3)2·6H2O, Fe(NO3)3·9H2O (molar ratio of 1:3) and 0.149 g of C800, 0.149 g of Co(NO3)2·6H2O and Fe(NO3)3·9H2O (molar ratio of 1:3) and 0.298 g of C800, and the corresponding catalysts 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC were prepared.

[0044] Example 3 Determination of the optimal composite ratio of carbon material / Fe3Co alloy

[0045] The degradation rates of 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC in 5 minutes were 92.80%, 95.66%, and 99.36%, respectively. The amount of pine needle biochar doped in the catalyst was directly proportional to the BPA degradation efficiency. The leaching amounts of cobalt (Co) and iron (Fe) ions are shown in Table 1. To balance ion leaching and BPA degradation efficiency, 0.5Fe3Co@BC was selected as the optimal catalyst.

[0046] Table 1 Leaching amount of cobalt (Co) and iron (Fe) ions in different catalysts

[0047]

[0048] Example 4: Ability of 0.5Fe3Co@BC to degrade BPA under different conditions

[0049] At 25°C, the catalyst (20 mg) was added to 100 mL of a 20 mg / LBPA solution under magnetic stirring, followed by the addition of PMS (20 mg). Next, 1.5 mL of the supernatant was taken and immediately filtered with a 0.22 µm nylon filter, then mixed with 0.15 mL of methanol to detect the BPA content. C800, 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC were added to the BPA-containing water with peroxymonosulfate (PMS) and reacted for 5 minutes. The BPA degradation efficiency was calculated using the formula: BPA degradation rate = (1-C / C0) × 100%, where C is the BPA content after degradation and C0 is the initial BPA content. The results are shown in Table 1. Figure 1 , Figure 1 a is the BPA removal efficiency of different systems within 5 minutes; the effects of BPA initial concentration 1b, PMS dosage 1c, catalyst dosage 1d, pH value 1e, and temperature f on BPA degradation efficiency.

[0050] from Figure 1 As shown in Figure 1, PMS alone achieved a BPA degradation efficiency of 5.15% in 5 minutes. When activated by C800, the degradation rate reached 61.68% in 5 minutes. The degradation rates of 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC were 92.80%, 95.66%, and 99.36%, respectively, in 5 minutes. The amount of pine needle biochar doped in the catalyst was directly proportional to the BPA degradation efficiency. The porous structure of 0.5Fe3Co@BC exposes more metal sites, expands the adsorption space, and promotes the exposure of active species to BPA molecules. Therefore, the unique porous biochar-encapsulated alloy structure triggers a rapid adsorption-degradation coupling process, resulting in efficient BPA removal.

[0051] Figure 1 b. Figure 1 c. and Figure 1 d shows the effects of initial BPA concentration, PMS dosage, and catalyst dosage on BPA degradation performance. Figure 1 In b, as the initial BPA concentration increased from 10 mg / L to 40 mg / L, the BPA degradation efficiency decreased. Figure 1 c. BPA degradation efficiency increases with increasing PMS dosage. In particular, complete BPA removal was achieved within 5 minutes for the 0.40 and 0.50 g / L systems. Increasing the amount of PMS increases the concentration of reactive free radicals in the reaction system, enabling efficient and rapid BPA degradation. Figure 1d. The amount of catalyst is positively correlated with the BPA degradation reaction rate. With the increase of catalyst dosage (10-50 mg), the BPA degradation rate accelerates.

[0052] This study also investigated the initial pH value ( Figure 1 e) Effect on BPA decomposition: During the degradation process of BPA, the solution pH remained the same as the initial value. The degradation rate of BPA continued to increase as the pH increased from 3.08 to 9.14. At pH 9.14, BPA was completely degraded within 5 minutes. In weakly acidic and weakly alkaline environments, self-annihilation and the reaction with H + The reactive oxygen species in the reaction are relatively small, while a large amount of reactive oxygen species participates in the degradation reaction of pollutants, thereby increasing the degradation rate of pollutants.

[0053] Figure 1 The degradation rate is positively correlated with the reaction temperature. For the degradation reaction at 45°C, the degradation rate of BPA reached 99.66% after 5 minutes. Furthermore, complete BPA degradation was achieved after 4 minutes at 55°C. Meanwhile, at 55°C, the autolysis rates of BPA and PMS were only 8.01% and 9.13% after 5 minutes. High temperatures can accelerate the collision frequency between PMS, pollutants, and the catalyst, thereby speeding up the reaction.

[0054] Figure 2 The kinetic curve related to the degradation of BPA is shown. It can be seen from the figure that the degradation of BPA conforms to the pseudo-first-order kinetic equation.

[0055] Figure 3 is the pseudo-first-order kinetic constant (k) for BPA degradation at different temperatures, given by Figure 3 It can be seen that the kinetic constant of BPA degradation increases from 0.80421 to 1.35343 min as the temperature increases from 25 ℃ to 55 ℃. -1 , with the increase of temperature, the k value gradually increases, indicating that the activation of PMS is an endothermic process.

[0056] Example 5 Adsorption efficiency of 0.5Fe3Co@BC for BPA

[0057] The adsorption isotherm of 0.5Fe3Co@BC for BPA is shown in Figure 2. Figure 4 The experimental results show that the maximum adsorption capacity of 0.5Fe3Co@BC is 255.15 mg / g.

[0058] At different BPA concentrations, 20 mg of the catalyst was added to 100 ml of BPA solution (acetonitrile / water, 1 / 4, v / v) and shaken at a constant temperature of 150 rpm. After reaching adsorption equilibrium, the mixture was filtered through a 0.22 μm filter and the BPA concentration was detected by high performance liquid chromatography at 278 nm. Figure 5 As shown in Figure 3, the adsorption amount of the catalyst increases with increasing temperature. The temperature at which 0.5Fe3Co@BC reaches adsorption equilibrium is 55℃.

[0059] Example 6 Characterization of 0.5Fe3Co@BC Catalyst

[0060] The microstructure of the prepared materials was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Figure 6 .

[0061] like Figure 6 As shown in a, numerous micropores are observed on the surface of 0.5Fe3Co@BC. This is due to the porous structure of C800, which is convenient for the subsequent loading of metal elements. In the high magnification SEM image ( Figure 6 As can be seen in b), 0.5Fe3Co@BC maintains the advantage of a highly porous structure of the precursor, and the surface of the material presents an irregular pore morphology. TEM was introduced to observe the fine structure of 0.5Fe3Co@BC. The Fe3Co nanoparticles are spherical and relatively evenly anchored on the biochar. Figure 6 As shown in c. Figure 6 In the HRTEM image of 0.5Fe3Co@BC shown in d, lattice fringes of 0.2030 and 0.1438 nm corresponding to the (111) and (220) crystal planes of Fe3Co were observed, which further demonstrated that the Fe3Co alloy was successfully loaded onto the pine needle biochar. It was also observed that the radius of the polycrystalline diffraction ring corresponds to the interplanar spacing of the (111) and (220) crystal planes of Fe3Co, as shown in Figure 6 EDS mapping was used to detect surface elements to further determine the composition of the sample. The results showed that C, N, O, Fe and Co elements in 0.5Fe3Co@BC were uniformly and continuously distributed in the prepared catalyst, as shown in Figure 5. Figure 6 As shown in f.

[0062] The crystal structure and morphology of the prepared samples were characterized by X-ray diffraction (XRD), as shown in Figure 7a, All diffraction peaks of the obtained samples with different loading ratios, 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC, completely match those of Fe3Co (JCPDS card number 97-015-5843). This indicates that Fe3Co is successfully attached to the carbon material and that the high crystallinity of Fe3Co is not affected by the amount of pine needle biochar added.

[0063] In order to further verify the XRD results, Raman spectroscopy was performed on the materials. Figure 7 b, ID / IG of C800, 2Fe3Co@BC, 1Fe3Co@BC and 0.5Fe3Co@BC are 0.98, 0.93, 0.96 and 0.97 respectively. The ID / IG value of C800 is the largest, indicating that the carbon atoms are in a chaotic and disordered state. The pore structure and pore size distribution characteristics of the catalysts were studied. Figure 7 As shown in c, according to the International Union of Pure and Applied Chemistry (IUPAC) classification, the N2 adsorption-desorption curve of HB conforms to the type IV isotherm with an H3 type hysteresis loop (at P / P0 = 0.56-0.99). C800 shows a significantly increased specific surface area (1616.9 m 2 g −1 ), KHCO3 activation increased the specific surface area by about 185 times. After activation, the average pore size decreased from 14.75 nm to 4.18 nm, as shown in Figure 7 d, further confirming the extremely high micropore content of C800. Figure 7 d-7e show that the N2 adsorption / desorption isotherms of C800 and 0.5Fe3Co@BC are both type IV, and the H4 hysteresis loops are in the range of 0.5-0.99, which means that they have a porous structure with abundant micropores and mesopores. Table 2 shows the specific surface area and pore volume pore size distribution of Fe3Co@BC catalysts with different composite ratios. All materials have a good mesoporous structure (the average pore size of the mesopores is 2-50nm). Compared with C800, the specific surface area of 0.5Fe3Co@BC is reduced to 1218.08 m 2 g −1 The average pore size of 0.5Fe3Co@BC increases to 7.34 nm.

[0064] Table 2 Specific surface area and pore size of HB, C800, 2Fe3Co@BC, 1Fe3Co@BC, and 0.5Fe3Co@BC

[0065]

[0066] By adding several common anions and organic compounds in real life (including Cl - 、SO42- 、HCO3 - 、H2PO4 - 、CO3 2- 、NO3 - and HA), verifying the applicability of 0.5Fe3Co@BC catalyst. Figure 8 For Cl - 、SO4 2- 、HCO3 - 、H2PO4 - 、CO3 2- 、NO3 - Pseudo-first-order kinetic constants for BPA degradation in the presence of HA and BPA.

[0067] The experimental process was the same as in Example 4, and different anions were added to evaluate their effects on BPA degradation. Figure 9 As shown in a, SO4 2- and NO3 - Only slightly reduces the degradation efficiency; CO3 2− The presence of Cl and HA significantly reduces the overall degradation efficiency. - The presence of H2PO4 accelerates the degradation rate, and chloride ions have a significant positive effect. - It also showed a positive effect on the degradation of BPA.

[0068] Reusability is also an important consideration for the catalyst. BPA and PMS solutions were injected simultaneously through a circulating water multi-purpose vacuum pump, and the column was filled with 0.5Fe3Co@BC material. The column was run continuously for 8 hours, and the instantaneous effluent was taken to measure the BPA concentration to verify the stability of the material. Figure 10 .like Figure 9 As shown in Figure b, although the degradation rate decreased during the 8-hour dynamic cycle, the BPA removal rate was always higher than 87%, proving that the 0.5Fe3Co@BC catalyst has ideal cycling performance.

[0069] To evaluate the application of the catalyst in real water samples, water from the Xiaohei River in Hohhot, Inner Mongolia, and water from Manduhai Park were used to prepare a 20 mg / L BPA solution for degradation. 83.64% and 93.65% of the BPA in the Manduhai Lake and Xiaohei River water, respectively, were degraded. Figure 9 (c) The organic matter and ions present in the Xiaohei River water hindered the catalyst's degradation of BPA. The more pronounced decrease in BPA removal in lake water may be due to the presence of natural organic matter in the water sample, which competes with BPA for adsorption sites, thereby inhibiting BPA degradation by 0.5Fe3Co@BC.

[0070] Depend on Figure 9d It can be seen that the removal rates of 0.5Fe3Co@BC for basic blue 1, malachite green, oxytetracycline hydrochloride and tetracycline hydrochloride are 92.92% (24 min), 88.90% (24 min), 83.26% (14 min) and 90.10% (10 min), respectively. It can be seen that 0.5Fe3Co@BC can effectively degrade a variety of dyes and antibiotics by catalytic activation of PMS. Based on PMS activation, the catalytic degradation ability of the material for basic blue 1, malachite green, tetracycline hydrochloride and oxytetracycline hydrochloride was tested ( Figure 11 The results showed that 0.5Fe3Co@BC had the same good catalytic activity towards basic blue, malachite green, tetracycline hydrochloride and oxytetracycline hydrochloride.

[0071] Example 7 Stability of 0.5Fe3Co@BC

[0072] Furthermore, the surface morphology of 0.5Fe3Co@BC after use was tested, and the material structure did not change significantly after use ( Figure 12 ). Figure 13 Figure 3 is the XRD spectrum of catalyst 0.5Fe3Co@BC before and after degradation of BPA. There is no obvious change in the diffraction peak before and after the reaction, indicating that the crystal structure of the prepared material is relatively stable.

[0073] Example 8 Identification of active oxygen in 0.5Fe3Co@BC+PMS system

[0074] The experimental process was the same as that of Example 4, and different free radical scavengers were added to evaluate their effects on BPA degradation. Figure 14 As shown in a, the order of inhibition performance on BPA degradation is: p-BQ>>L-histidine>KI>MeOH>DMSO>TBA. When p-BQ was added to the system, the BPA removal rate dropped to 95.40% after 5 min. Since p-BQ has the strongest inhibitory effect on BPA degradation, it indicates that O2• − It dominated the reaction system. In the presence of L-histidine, the overall trend of BPA degradation reaction was observed to decrease. The final degradation rate of BPA was reduced to 97.57%. This indicates that 1 O2 also acts on the degradation of BPA. The addition of KI confirms the generation of free radicals on the catalyst surface, indicating that the degradation of BPA by 0.5Fe3Co@BC+PMS is a heterogeneous catalytic process. The addition of MeOH indicates that 0.5Fe3Co@BC can activate PMS to generate OH· and SO4· − The addition of TBA has a very weak effect on the degradation process of BPA, which indicates that OH• plays a small role in the reaction system. The addition of MeOH and TBA together indicate that OH• and SO4• −plays a role in BPA degradation, and SO4• − These results show that in the 0.5Fe3Co@BC+PMS+BPA system, including 1O2, SO4• − and OH• are the active species that degrade BPA, while O2• − It plays a major role in the degradation of BPA.

[0075] EPR experiments were performed using 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO) as a spin trapping agent ( Figure 14 b, 14c). The characteristic signals of DMPO-OH• (1:2:2:1, quartet) and DMPO-SO4•− (sextet) were detected in 0.5Fe3Co@BC+PMS, C800+PMS systems and PMS alone. These results indicate that OH• and SO4• − When only PMS was added (0 min), no DMPO-O2• − This indicates that PMS self-decomposition does not produce O2• − O2• was detected in 0.5Fe3Co@BC+PMS and C800+PMS systems. − characteristic signals, proving that 0.5Fe3Co@BC and C800 can activate PMS to produce O2• − The above results show that the O2• − , OH• and SO4• − Higher concentration. Figure 14 d using 2,2,6,6-tetramethyl-4-piperidone (TEMP) as 1 The EPR experiment was conducted using O2 spin trapping agents. 2.5 min after adding PMS and 0.5Fe3Co@BC or C800, both 0.5Fe3Co@BC+PMS and C800+PMS systems were observed. 1 The typical characteristic peak of O2 (1:1:1). This shows that Fe3Co@BC and C800 can activate PMS to produce 1 O2. Generated by Fe3Co@BC activating PMS 1 The stronger O2 characteristic peak signal intensity confirms that the Fe3Co@BC composite material produces a higher concentration of free radicals than the C800 carbon material. As mentioned above, both the activated pine needle biochar and the loaded Fe3Co can effectively activate PMS.

[0076] Example 9 Contribution of each component of 0.5Fe3Co@BC to the activation of PMS

[0077] Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the charge transfer between the catalyst, PMS and BPA. 0.5Fe3Co@BC showed a larger redox potential ( Figure 15 a), which corresponds to the electron-accepting behavior of PMS. The stronger current response means that 0.5Fe3Co@BC has a faster kinetic reaction rate and stronger catalytic ability than C800. Cyclic voltammetry confirmed the cyclic stability of the electron transport of the catalytic material. Similarly, 0.5Fe3Co@BC has a smaller circle diameter in the EIS graph (15b), showing a higher electron transfer rate. 0.5Fe3Co@BC has a stronger ability to activate PMS than C800. The above results show that after C800 is composited with Fe3Co, the electron transfer ability of the catalyst is enhanced, which is conducive to the activation of PMS. The electrochemical test results show that the prepared catalyst has good electron transfer performance and redox behavior.

[0078] The element changes in 0.5Fe3Co@BC before and after the degradation reaction were analyzed by XPS. Figure 15 The full-range spectrum in c shows the characteristic peaks of Fe, Co, C, N, and O elements, confirming that there is no significant change in the elemental composition of the catalyst before and after use. 0 The peaks of Co(Ⅱ) and Co(Ⅲ) are located at 777.60 eV, 781.93 eV and 796.89 eV, and 779.71 eV and 794.64 eV, respectively. The peaks at 785.17 eV and 800.12 eV are their satellite peaks. 0 The content of Fe(Ⅱ) decreased from 8.64% to 3.00%, the content of Co(Ⅱ) decreased from 35.87% to 25.86%, and the proportion of Co(Ⅲ) increased from 22.76% to 25.28% (Figure 15d). 0 The peaks of Fe(Ⅱ) and Fe(Ⅲ) are located at 707.03 eV, 714.17 eV and 726.62 eV, and 710.85 eV and 723.24 eV, respectively. The peaks at 728.39 eV and 730.20 eV are their satellite peaks. 0 The content of Fe (Ⅱ) decreased from 8.30% to 1.66%, while the content of Fe (Ⅱ) increased from 29.16% to 31.27%, and the proportion of Fe (Ⅲ) increased from 38.07% to 46.00% ( Figure 15 e). The contents of metallic Fe and metallic Co decreased significantly after the reaction, indicating that the Fe3Co alloy participated in the PMS activation reaction and played an important role in the degradation of BPA.

[0079] The relative contents of C, N, O, Fe and Co before and after the reaction are shown in Table 3.

[0080] Table 3 XPS element contents of different samples

[0081]

[0082] Example 10 Degradation pathway of BPA

[0083] The degradation intermediates of BPA were determined by HPLC-MS, the degradation pathway of BPA was inferred based on the intermediates, and the structural formula was deduced based on the m / z values of the fragment ions. 13 intermediates were generated by BPA, such as Figure 16 As shown. BPA is converted to 3-hexen-1-ol via two pathways. The first involves the cleavage of the C-H bond connecting the two benzene rings in the BPA molecule, forming 1-(4-hydroxyphenyl)ethanol (N4). The hydroxyl group is then oxidized to a carbonyl group, forming p-hydroxyacetophenone (N5). Finally, N5 loses its hydroxyl group to form acetophenone (N6). The second involves the loss of two phenolic hydroxyl groups in the BPA molecule, forming 2,2-diphenylpropane (N2). N2 then loses two methyl groups, forming benzhydrol (N3). N3 opens the right ring and undergoes electronic rearrangement, producing a monocyclic aromatic hydrocarbon (N7). Finally, a ring-opening reaction further converts it to aliphatic compounds (N8 and N9). After conversion to 3-hexen-1-ol (N10) via these two pathways, it is subsequently converted to 2-hexanone (N11), 2-pentanol (N12), sec-butanol (N13), and finally butane (N14), which is ultimately mineralized into carbon dioxide and water. Table 4 describes the mass spectra of BPA and 13 intermediates.

[0084] Table 4 Mass spectra of BPA and 13 intermediates

[0085]

[0086] The total organic carbon (TOC) removal rate reflects the degree of BPA mineralization in the 0.5Fe3Co@BC+PMS system. Figure 17 It can be seen that the TOC removal rate is positively correlated with the C800 doping level. The TOC removal rates of 2Fe3Co@BC and 1Fe3Co@BC are 48.36% and 53.73%, respectively. The TOC removal rate of 0.5Fe3Co@BC reaches 61.05%.

[0087] In summary, this invention is the first to construct a pine needle-derived biochar-loaded Fe3Co alloy catalyst (0.5Fe3Co@BC). The loading of the Fe3Co alloy optimizes the charge distribution, giving 0.5Fe3Co@BC highly efficient catalytic performance, ultimately achieving an ultra-high degradation rate of 99.36% in 5 minutes. EPR and electrochemical experiments confirmed that the loading of the Fe3Co alloy improved electron transfer efficiency, thereby enhancing the ability to activate PMS and the degradation efficiency of BPA. The BPA removal rate remained above 87% during the 8-hour dynamic cycle. In addition, 0.5Fe3Co@BC also exhibited good degradation performance for antibiotics and dyes. The catalytic degradation of BPA is a process involving the combined action of free radicals and non-free radicals. O2• − The study systematically proposes possible pathways and intermediates for BPA degradation. Finally, a mechanism for BPA degradation by 0.5Fe3Co@BC activated by PMS is proposed. This research provides new insights into the design of Fe3Co alloy catalysts for the efficient and rapid degradation of organic pollutants by peroxymonosulfate.

Claims

1. Application of a method for preparing a biochar composite material, characterized in that: The application method is as follows: Step 1: adding a biochar composite material Fe3Co@BC and peroxymonosulfate to water containing bisphenol A, wherein the dosage of Fe3Co@BC is 0.2 g / L and the dosage of peroxymonosulfate is 0.2 g / L; Step 2: react at 25°C for 5 minutes; The preparation method of the biochar composite material Fe3Co@BC comprises the following steps: S1. Hydrothermal biochar preparation: Pine needle powder was mixed with distilled water and subjected to hydrothermal reaction at 180°C for 12 hours to obtain hydrothermal biochar; S2. Preparation of porous biochar: Hydrothermal biochar and KHCO3 were mixed in a weight ratio of 1:3-5, ball-milled for 30 minutes, and then heated to 800°C at a heating rate of 5°C / min under nitrogen atmosphere and held for 2 hours to obtain porous biochar; S3. Synthesis of Fe3Co@BC: The porous biochar was immersed in a Co / Fe nitrate ethanol solution, dried and pyrolyzed for 2 hours to generate Fe3Co alloy which was simultaneously loaded on the porous biochar, i.e., Fe3Co@BC. The Co / Fe nitrate ethanol solution is an ethanol solution in which the molar ratio of Co(NO3)2·6H2O to Fe(NO3)3·9H2O is 1:

3.

2. The use of the method for preparing a biochar composite material according to claim 1, characterized in that: The mass ratio of the Fe3Co alloy to the porous biochar is 1:

2.

3. The use of the method for preparing a biochar composite material according to claim 1, characterized in that: In the step S3, after drying, the mixture is heated to 700° C. at a heating rate of 5° C. / min in a nitrogen atmosphere and pyrolyzed for 2 hours.

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