Biochar-loaded cobalt ferrite magnetic composite catalytic material and preparation method thereof

Abstract

The invention discloses a preparation method of a charcoal-loaded cobalt ferrite magnetic composite catalytic material, which is specifically implemented according to the following steps: step 1, selecting green tea as a biomass precursor, and carrying out carrier WT pretreatment; step 2, preparing a magnetic composite catalytic material of biochar loaded cobalt ferrite; step 2.1, preparing a suspension; step 2.2, preparing a solid product; step 2.3, preparing a dried precursor; and step 2.4, preparing the magnetic composite catalytic material of the biochar loaded cobalt ferrite. According to the method, the reaction rate is remarkably increased, the problem of magnetic agglomeration of active components is solved, non-free radical dominance is achieved, the anti-interference performance is high, and efficient magnetic recovery and waste utilization are achieved. The invention further discloses the magnetic composite catalytic material of the biochar loaded cobalt ferrite and application of the magnetic composite catalytic material.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of water treatment advanced oxidation technology, and relates to a magnetic composite catalytic material of biochar loaded cobalt ferrite, and further relates to a preparation method and application of the magnetic composite catalytic material of biochar loaded cobalt ferrite. BACKGROUND

[0002] Sulfamethoxazole (SMX) is a typical sulfonamide antibiotic. Due to its wide application in medicine and livestock breeding industry, its detection rate in various water environments is extremely high. SMX has strong biological toxicity and is difficult to be degraded by traditional biological treatment process. In recent years, the advanced oxidation technology (SR-AOPs) based on persulfate (PMS) has become a research hotspot for degrading persistent organic pollutants in water because the sulfate radicals generated by the advanced oxidation technology have high oxidation potential and are environmentally friendly. At present, transition metal oxides (such as spinel ferrite CoFe2O4) are generally used as heterogeneous catalysts to activate PMS in the academic and industrial fields. In order to improve the catalytic efficiency, researchers begin to introduce biochar as a carrier.

[0003] Yinghao Li et al. in “Highly efficient degradation of sulfamethoxazole (SMX) by activating peroxymonosulfate (PMS) with CoFe2O4 in a wide pH range” (published in 2021, journal name “Separation and Purification Technology”, article number 119403) confirmed that pure CoFe2O4 has a wide pH range in the process of activating PMS to degrade SMX and has magnetic recovery potential, which proves the catalytic core role of cobalt ferrite in the system. However, pure CoFe2O4 is prone to agglomeration due to strong magnetic dipole interaction, which leads to small specific surface area and insufficient exposure of active sites, thereby limiting the further breakthrough of catalytic efficiency.

[0004] In their paper "Tea waste-enhanced degradation of phenolic and pharmaceutical pollutants in the ferric ion / peroxymonosulfate system" (published in 2025 in the *Journal of Environmental Chemical Engineering*, Vol. 13, No. 2, Article No. 115336), Hanh Thi My Truong et al. demonstrated the unique biochemical value of tea waste in assisting the degradation of antibiotics by directly adding it to the system and utilizing its catechins to promote metal ion cycling. Although the tea waste precursor has an enhancing effect, the homogeneous reaction system formed by its direct addition faces challenges such as metal ion loss and difficulty in carrier separation, and the degradation time is too long (2 hours), making it difficult to meet the needs of continuous industrial processing.

[0005] In their paper "Efficient peroxymonosulfate activation by magnetic CoFe2O4 nanoparticle immobilized on biochar toward sulfamethoxazole degradation: Performance, mechanism and pathway" (published in 2023 in Applied Surface Science, Vol. 615, Article No. 156398), Minghui Xiong et al. prepared cobalt ferrite particles supported on rapeseed straw biochar and achieved the degradation of SMX by the magnetic composite material (93% degradation rate in 20 minutes), demonstrating the effectiveness of biochar as a carrier in improving the dispersibility of metal oxides. However, in the face of inorganic anions (such as chloride ions Cl-) in complex water quality... - Bicarbonate ions (HCO3-) - It is easily disturbed.

[0006] Therefore, the following shortcomings still exist in practical applications and technical performance: pure metal oxides are prone to agglomeration; homogeneous systems are difficult to recover; existing biochar composite materials mostly rely on free radical pathways for degradation, which is problematic when facing inorganic anions (such as Cl-) in complex water quality. - HCO3 - It is easily disturbed. Summary of the Invention

[0007] The purpose of this invention is to provide a magnetic composite catalytic material of cobalt ferrite supported on biochar, which solves the problems of easy catalyst aggregation, difficulty in recovery of homogeneous systems, long reaction cycle, slow degradation rate and poor anti-interference ability in complex water quality in the prior art.

[0008] A second objective of this invention is to provide a method for preparing the above-mentioned biochar-supported cobalt ferrite magnetic composite catalytic material.

[0009] A third objective of this invention is to provide the application of biochar-supported cobalt ferrite magnetic composite catalytic materials.

[0010] The technical solution adopted in this invention is a method for preparing a magnetic composite catalytic material of cobalt ferrite supported on biochar, which is implemented according to the following steps:

[0011] Step 1: Green tea is selected as the biomass precursor for pretreatment of tea residue biomass powder (WT). Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar; Step 2.1, prepare the suspension; Step 2.2, prepare the solid product; Step 2.3: Prepare the dried precursor; Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0012] The invention is further characterized by: In step 1, the green tea is unfermented tea with a polyphenol content of 15wt%~40wt% and a catechin content of 10wt%~25wt%.

[0013] In step 1, green tea is soaked in deionized water at 80-100℃ for 1.5-2.5 hours at a solid-liquid ratio of 1g:(40-60)mL, and then filtered to obtain tea residue. The tea dregs are dried at 100-110℃, then crushed and passed through a 100-mesh sieve to obtain WT.

[0014] In step 2.1, cobalt nitrate (Co(NO3)2·6H2O) and ferric nitrate (Fe(NO3)3·9H2O) are weighed according to a Co / Fe molar ratio of 1:(1.8-2.2), and Co(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed to form a metal salt; The metal salt and pretreated WT were dispersed in deionized water and subjected to ultrasonic treatment for 25-35 minutes to obtain a suspension; the mass of the metal salt accounted for 25%-35% of the mass of the pretreated WT. The solid mass of the metal salt and the pretreated WT was compared with the liquid-solid ratio of deionized water at a ratio of 1 g: (6-8) mL.

[0015] In step 2.2, the suspension is transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 150-170℃ for 8-12 hours to obtain a solid product.

[0016] In step 2.3, the solid product is washed with deionized water and dried at 55-65°C to obtain the dried precursor.

[0017] In step 2.4, the dried precursor is placed in a muffle furnace and heated to the target temperature at a rate of 3-7℃ / min, the target temperature being 450-750℃. The material was pyrolyzed and activated at the target temperature for 80-100 minutes, and then cooled to room temperature to obtain a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0018] The target temperature is any one of 500℃, 600℃, or 700℃.

[0019] The second technical solution adopted in this invention is a magnetic composite catalytic material of cobalt ferrite supported by biochar, which is obtained by the preparation method of magnetic composite catalytic material of cobalt ferrite supported by biochar.

[0020] The third technical solution adopted in this invention is the application of biochar-supported cobalt ferrite magnetic composite catalytic material in advanced oxidation technology for water treatment.

[0021] The beneficial effects of this invention are: (1) Significantly improved reaction rate: This invention can degrade SMX 100% in just 15 minutes, with a reaction kinetic constant k as high as 0.1967 min. -1 This improves processing efficiency several times over.

[0022] (2) Solving the problem of magnetic agglomeration of active components: This invention utilizes the porous structure of tea residue to achieve highly dispersed loading, increasing the specific surface area to 339.73 m². 2 / g, which greatly improves the utilization rate of active sites.

[0023] (3) Non-free radical dominant, strong anti-interference: Unlike the free radical pathway that relies on easily disturbed free radicals, this invention generates more active species through calcination at 600℃, and has higher stability under complex water quality and wide pH conditions.

[0024] (4) Achieving efficient magnetic recovery and waste utilization: The saturation magnetization of the material of this invention reaches 17.23 emu / g, which can quickly complete magnetic separation. At the same time, it turns waste into treasure, significantly reduces the cost of reagents, and has significant economic and environmental benefits. Attached Figure Description

[0025] Figure 1This is a graph showing the degradation performance analysis of SMX by different systems in Example 1 of the present invention; Figure 2 These are kinetic analysis diagrams of different systems for SMX in Embodiment 1 of the present invention; Figure 3 This is a graph showing the effect of calcination temperature on degradation performance in Example 1 of the present invention; Figure 4 This is a graph showing the effect of CoFe2O4 loading on degradation performance in Example 1 of the present invention; Figure 5 This is a graph showing the effect of the Co / Fe molar ratio on degradation performance in Example 1 of this invention; Figure 6 This is an analysis diagram of metal ion leaching under different Co / Fe molar ratios in Example 1 of the present invention; Figure 7 This is a SEM image of WT-600 in Embodiment 1 of the present invention; Figure 8 This is a SEM image of CoFe2O4-600 in Example 1 of this invention; Figure 9 This is a SEM image of 30wt% CoFe2O4@WT-600 in Example 1 of this invention; Figure 10 This is an EDS elemental carbon (C) scan of 30wt% CoFe2O4@WT-600 in Example 1 of the present invention; Figure 11 This is an EDS scan of the surface oxygen (O) of 30wt% CoFe2O4@WT-600 in Example 1 of the present invention; Figure 12 This is an EDS elemental scan of cobalt (Co) in 30wt%CoFe2O4@WT-600 in Example 1 of this invention; Figure 13 This is an EDS elemental scan of iron (Fe) in 30wt%CoFe2O4@WT-600 in Example 1 of this invention; Figure 14 This is the XRD pattern of the material in Example 1 of this invention; Figure 15 This is the FT-IR spectrum of the material in Example 1 of this invention; Figure 16 This is the N2 adsorption-desorption isotherm of the material in Example 1 of this invention (illustration: pore size distribution curve); Figure 17 This is a hysteresis loop diagram of the material in Embodiment 1 of the present invention; Figure 18This is a graph showing the degradation trend of SMX in simulated aquaculture wastewater by the 30wt%CoFe2O4@WT-600 / PMS system in Example 1 of this invention. Figure 19 This is a graph showing the trend of COD change in simulated aquaculture wastewater in the 30wt%CoFe2O4@WT-600 / PMS system of Example 1 of this invention; Figure 20 The 30wt% CoFe2O4@WT-600 / PMS system in Example 1 of this invention is used to treat NH4 in simulated aquaculture wastewater. + -N trend chart; Figure 21 The 30wt% CoFe2O4@WT-600 / PMS system in Example 1 of this invention is used to treat PO4 in simulated aquaculture wastewater. 3- -P trend chart; Figure 22 This is a graph showing the trend of TN changes in simulated aquaculture wastewater in the 30wt%CoFe2O4@WT-600 / PMS system of Example 1 of this invention; Figure 23 This is a graph showing the trend of TP changes in simulated aquaculture wastewater in the 30wt%CoFe2O4@WT-600 / PMS system of Example 1 of this invention; Figure 24 It is Cl in Embodiment 1 of the present invention - Effect of 30wt% CoFe2O4@WT-600 / PMS system on the degradation of SMX; Figure 25 It is NO3 in Embodiment 1 of the present invention - Effect of 30wt% CoFe2O4@WT-600 / PMS system on the degradation of SMX; Figure 26 The HCO3 in Embodiment 1 of this invention - Effect of 30wt% CoFe2O4@WT-600 / PMS system on the degradation of SMX; Figure 27 This describes the effect of humic acid (HA) on the degradation of SMX in the 30wt%CoFe2O4@WT-600 / PMS system in Example 1 of this invention. Detailed Implementation

[0026] The following detailed description is provided in conjunction with specific implementation methods.

[0027] The preparation method of biochar-supported cobalt ferrite magnetic composite catalytic material is carried out according to the following steps: Step 1: Green tea was selected as the biomass precursor and the carrier was pretreated by WT.

[0028] Green tea is an unfermented tea, with a polyphenol content of 15wt%~40wt% and a catechin content of 10wt%~25wt%. A polyphenol content of 20wt%-35wt% can be selected.

[0029] Green tea was soaked in deionized water at 80-100℃ for 1.5-2.5 hours at a solid-liquid ratio of 1g:(40-60)mL to simulate daily use. After filtration, tea residue was obtained. The tea residue was dried at 100-110℃, then pulverized and passed through a 100-mesh sieve to obtain WT.

[0030] Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0031] Step 2.1, prepare the suspension.

[0032] Weigh out Co(NO3)2·6H2O and Fe(NO3)3·9H2O according to a Co / Fe molar ratio of 1:(1.8-2.2), and mix Co(NO3)2·6H2O and Fe(NO3)3·9H2O to form a metal salt; The metal salt and pretreated WT were dispersed in deionized water and subjected to ultrasonic treatment for 25-35 minutes to obtain a suspension. The metal salt accounted for 25%-35% of the mass of the pretreated WT.

[0033] The solid mass of the metal salt and the pretreated WT was compared with the liquid-solid ratio of deionized water at a ratio of 1 g: (6-8) mL.

[0034] Step 2.2, prepare solid product.

[0035] The suspension was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 150-170℃ for 8-12 hours to obtain a solid product.

[0036] Step 2.3: Prepare the dried precursor.

[0037] The solid product was washed with deionized water and dried at 55-65℃ to obtain the dried precursor.

[0038] Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0039] The dried precursor was placed in a muffle furnace and heated to the target temperature (450-750℃) at a rate of 3-7℃ / min. Pyrolysis activation was performed at the target temperature for 80-100 min, followed by cooling to room temperature to obtain a biochar-supported cobalt ferrite magnetic composite catalytic material.

[0040] The target temperature is 500℃, 600℃ or 700℃.

[0041] Example 1 The preparation method of biochar-supported cobalt ferrite magnetic composite catalytic material is carried out according to the following steps: Step 1: Green tea is selected as the biomass precursor for pretreatment of tea residue biomass powder (WT).

[0042] Green tea was selected as the biomass precursor. The content of tea polyphenols was 25 wt%, and the content of catechins was 15 wt%.

[0043] Green tea was soaked in deionized water at 80℃ for 2 hours at a solid-liquid ratio of 1g:50mL to simulate daily use. After filtration, tea residue was obtained. The tea residue was dried at 105℃, then pulverized and passed through a 100-mesh sieve to obtain WT.

[0044] Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0045] Step 2.1, prepare the suspension.

[0046] Weigh 1.86g of Co(NO3)2·6H2O, 5.16g of Fe(NO3)3·9H2O and 5g of WT and disperse them in 35mL of deionized water. Sonicate for 30min to obtain a suspension.

[0047] Step 2.2, prepare solid product.

[0048] The suspension was transferred to a 100 mL polytetrafluoroethylene-lined reactor and reacted at 160 °C for 10 h to obtain a solid product.

[0049] Step 2.3: Prepare the dried precursor.

[0050] The solid product was washed with deionized water and dried at 60°C to obtain the dried precursor.

[0051] Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0052] The dried precursor was placed in a muffle furnace and heated to 600°C at a rate of 5°C / min, and held for 90 min for pyrolysis activation. After cooling to room temperature, a magnetic composite catalytic material of cobalt ferrite supported on biochar, namely CoFe2O4@WT-600 catalytic material, was obtained.

[0053] Under the premise of a fixed pyrolysis temperature (600℃) and metal loading, and controlling the Co / Fe molar ratio to 1:4, the obtained Co sample 0.60 Fe 2.40 O4@WT-600; controlling the Co / Fe molar ratio at 1:3, the resulting sample contains Co. 0.75 Fe 2.25O4@WT-600; controlling the Co / Fe molar ratio at 1:2, the resulting sample is CoFe2O4@WT-600; controlling the Co / Fe molar ratio at 1:1, the resulting sample is Co 1.50 Fe 1.50 O4@WT-600.

[0054] Based on CoFe2O4@WT-600, the effect of CoFe2O4 loading on catalytic performance was further investigated. By controlling the mass ratio of CoFe2O4 to WT, composite materials with loadings of 10wt%, 20wt%, 30wt%, and 40wt% were prepared.

[0055] In addition, to elucidate the synergistic effect between the bimetals and the contribution of the support, pure biochar (WT-600), single iron-supported biochar (Fe@WT-600), and single cobalt-supported biochar (Co@WT-600) were prepared under the same conditions as control groups.

[0056] The degradation effects of different systems on SMX were compared under the conditions of PMS concentration of 1.0 mM, SMX concentration of 10 mg / L, catalyst dosage of 0.05 g / L, and initial pH of 7.0. Figure 1 As shown, the adsorption removal rates of SMX by WT-600 and 30wt%CoFe2O4@WT-600 were both below 6%, indicating that the adsorption capacity of the materials was weak. PMS alone showed a removal rate of 27%, which was mainly attributed to the direct oxidation of PMS and the singlet oxygen generated by its self-decomposition. 1 O2). In contrast, the 30wt%CoFe2O4@WT-600 / PMS system exhibited higher catalytic activity, achieving complete degradation (100%) of SMX within 15 min.

[0057] Depend on Figure 2 The first-order kinetic fitting results show that the reaction rate constant of the 30wt%CoFe2O4@WT-600 / PMS system is ( k =0.1967 min 1 The concentration was higher than Co@WT-600 / PMS (0.1253 min). 1 ) and Fe@WT-600 / PMS (0.0081 min) 1This demonstrates a significant synergistic catalytic effect between the active sites of Co and Fe. Furthermore, compared to the CoFe₂O₄-600 / PMS system, the 30wt% CoFe₂O₄@WT-600 / PMS system increased the removal rate of SMX by 47.8%, and the reaction rate constant also increased to 9.1 times. This is because the abundant functional groups on the biochar surface not only provide more active sites but also act as electron donors to accelerate the removal of Co. 3+ / Co 2+ and Fe 3+ / Fe 2+ The redox cycle significantly improves the activation efficiency and degradation rate of PMS.

[0058] like Figures 3-6 As shown, the effects of calcination temperature, CoFe2O4 loading, and Co / Fe molar ratio on catalytic performance were systematically investigated. Figure 3 As shown, the effect of calcination temperature on the degradation rate of SMX exhibits a trend of first increasing and then decreasing, with 600℃ being the optimal calcination temperature. This is attributed to the fact that a suitable calcination temperature is conducive to the formation of a well-developed porous structure in WT, while excessively high temperatures (>600℃) may lead to the collapse of the porous structure. The effect of CoFe2O4 loading is as follows: Figure 4 As shown, the degradation rate increases with increasing loading, peaking at 30 wt%. When the loading exceeds 30 wt%, the degradation rate decreases, possibly due to excessive loading causing CoFe2O4 aggregation and exposing fewer active sites. Figure 5 As shown, by adjusting the Co / Fe molar ratio, 30wt% CoFe2O4@WT-600 with a standard spinel ratio exhibited the strongest activation ability. The degradation rate of SMX reached 100% within 15 minutes, significantly better than other ratio samples. Furthermore, to evaluate the material's stability and environmental safety, the metal leaching of different Co / Fe molar ratio systems after the reaction was tested, such as... Figure 6 As shown, the results indicate that the Co ion leaching concentration of each sample ranged from 0.42 to 0.77 mg / L (specifically, 30wt% Co leaching concentration was 0.42–0.77 mg / L). 1.50 Fe 1.50 O4@WT-600<30wt%Co 0.75 Fe 2.25 O4@WT-600<30wt%Co 0.60 Fe 2.40 The concentrations of O4@WT-600 and 30wt%CoFe2O4@WT-600 were both below the surface water environmental quality standard limit (1 mg / L). Fe ion leaching was between 0.10 and 0.18 mg / L. In conclusion, 30wt%CoFe2O4@WT-600 exhibited the best catalytic effect and can be considered the optimal catalyst for subsequent mechanism studies.

[0059] The microstructure of the material was observed using SEM, such as... Figure 7 As shown, WT-600 has a honeycomb porous structure. (As indicated...) Figure 8 As shown, CoFe2O4-600 particles aggregate due to magnetic attraction, forming clusters. (As...) Figure 9 As shown, in the 30wt% CoFe2O4@WT-600 composite material, CoFe2O4 was successfully anchored on the surface and in the pores of biochar. Compared with CoFe2O4-600, its aggregation degree was significantly reduced, and the active sites were effectively exposed. Figures 10-13 As shown, EDS mapping reveals that C, O, Co, and Fe elements are uniformly distributed within the selected region, confirming the successful loading of CoFe2O4 onto the WT support.

[0060] like Figure 14 As shown, WT-600 exhibits a broad amorphous carbon peak at 23.04°, while the diffraction peak at 29.38° corresponds to CaCO3 (PDF No. 97-019-1859), which may originate from the pyrolysis residues of minerals in the biomass precursor. The diffraction peaks of 30wt% CoFe2O4@WT-600 in the 30.09°~62.59° region correspond to spinel-type CoFe2O4 (JCPDS No. 22-1086), indicating the successful loading of CoFe2O4.

[0061] like Figure 15 As shown, in the FT-IR spectrum, at 564 cm⁻¹ -1 The nearby absorption peaks are attributed to vibrational absorption peaks of metal oxides, which are characteristic peaks of CoFe2O4. Additionally, at 1145 cm⁻¹... -1 1585 cm -1 and 3422 cm -1 The absorption peaks at these locations correspond to CO, C=C, and OH, respectively. The main characteristic peaks of CoFe2O4-600 and WT-600 can be observed on 30wt% CoFe2O4@WT-600, further indicating that CoFe2O4 was successfully loaded onto WT.

[0062] The specific surface area and pore size distribution of the catalyst material were analyzed using N2 adsorption-desorption isotherms, and the results are as follows: Figure 16 As shown in Table 1, 30wt%CoFe2O4@WT-600 exhibits a type IV isotherm and an H3 hysteresis loop, indicating the presence of abundant mesopores and some micropores in the system. The pore structure parameters of the material are shown in Table 1. The specific surface area of ​​30wt%CoFe2O4@WT-600 is 339.73 m² / s. 2 / g) and pore volume (0.634cm) 3The specific surface area ( / g) is 7.08 and 9.6 times that of WT-600, respectively. The increase in specific surface area indicates that the loading of CoFe2O4 altered the pore structure of WT, resulting in a sharp increase in specific surface area. The magnetic properties of the material are evaluated as follows: Figure 17 As shown, the 30wt%CoFe2O4@WT-600 and CoFe2O4-600 samples exhibit S-shaped magnetization curves, indicating that both samples are ferromagnetic materials. The saturation magnetization (M) of 30wt%CoFe2O4@WT-600 is shown in the figure. s The concentration was 17.23 emu / g. After the degradation experiment, it can be quickly separated and recovered from the aqueous solution using magnetic recovery technology to avoid secondary pollution.

[0063] Table 1 Pore structure parameters of the material

[0064] In natural aquatic environments, coexisting inorganic anions (such as Cl-) NO3 HCO3 Natural organic compounds (such as humic acid) typically interfere with advanced oxidation processes by quenching active species or competing for active sites. This study evaluated the impact of introducing different concentrations of interfering substances on SMX removal performance. Figure 24 As shown, low concentration (1 mM) Cl It has a slight inhibitory effect on SMX degradation. However, with Cl... Increasing the concentration to 10 mM and 50 mM actually increased the degradation rate. This is attributed to Cl... Can be with SO4 • It reacts with •OH to form chlorine free radicals (HOCl). • and Cl • These free radicals, although having lower oxidation potentials, exhibit stronger selectivity, thereby accelerating the conversion of SMX. For example... Figure 25 As shown, NO3 It exhibits a slight negative impact on the system; even at high concentrations, SMX can still be completely degraded within 15 minutes. For example... Figure 26 As shown, in contrast, HCO3 It exhibits a certain inhibitory effect on the reaction rate. When HCO3... When the concentration increased from 0 to 50 mM, the SMX removal efficiency decreased from 100% to 80.49%. This is due to HCO3... Able to quench SO4 • The HCO3- formed by the reaction with •OH has relatively weak oxidizing power. • In addition, such as Figure 27Although HA exerted some inhibitory effect due to competition for active sites, the system still maintained high degradation activity.

[0065] To evaluate the practical application potential of the 30wt%CoFe2O4@WT-600 / PMS system under complex water quality conditions, this example uses actual livestock wastewater from a pig farm as the background. Due to the low concentration of SMX in the raw water, to accurately determine the degradation kinetics, an SMX standard solution was added to the raw water to adjust its initial concentration to 10 mg / L, thus preparing the simulated livestock wastewater to be treated. The water quality characteristics of the raw water (before the addition of the drug) are shown in Table 2.

[0066] Table 2. Water quality characteristics of actual pig farming wastewater

[0067] like Figures 18-23 As shown, the experimental results indicate that under the conditions of catalyst dosage of 0.1 g / L and PMS concentration of 1 mM, the system achieved a 70% SMX removal rate within 30 minutes. Simultaneously, monitoring revealed increases in COD and ammonia nitrogen (NH4+) in the raw water. + -N), total phosphorus (TP), phosphate (PO4) 3- The levels of phosphorus (P) and total nitrogen (TN) also showed varying degrees of decline. This phenomenon indicates that while the system degrades the target antibiotic SMX, it also has a certain removal effect on other pollutants in the actual wastewater.

[0068] Example 2 The preparation method of biochar-supported cobalt ferrite magnetic composite catalytic material is carried out according to the following steps: Step 1: Green tea was selected as the biomass precursor and the carrier was pretreated by WT.

[0069] Green tea is an unfermented tea, with a polyphenol content of 15 wt% and a catechin content of 10 wt%.

[0070] Green tea was soaked in deionized water at 80℃ for 1.5 hours at a solid-liquid ratio of 1g:40mL to simulate daily use. After filtration, tea residue was obtained. The tea residue was dried at 100℃, then pulverized and passed through a 100-mesh sieve to obtain WT.

[0071] Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0072] Step 2.1, prepare the suspension.

[0073] Weigh out Co(NO3)2·6H2O and Fe(NO3)3·9H2O according to a Co / Fe molar ratio of 1:2, and mix Co(NO3)2·6H2O and Fe(NO3)3·9H2O to form a metal salt; The metal salt was dispersed with pretreated WT in deionized water and subjected to ultrasonic treatment for 25 minutes to obtain a suspension. The metal salt accounted for 25% of the mass of the pretreated WT.

[0074] The solid mass of the metal salt and the pretreated WT was 1 g:6 mL in liquid-solid ratio with the deionized water.

[0075] Step 2.2, prepare solid product.

[0076] The suspension was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 150°C for 8 hours to obtain a solid product.

[0077] Step 2.3: Prepare the dried precursor.

[0078] The solid product was washed with deionized water and dried at 55°C to obtain the dried precursor.

[0079] Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0080] The dried precursor was placed in a muffle furnace and heated to the target temperature of 450℃ at a rate of 3℃ / min. Pyrolysis activation was performed at the target temperature for 80 min, followed by cooling to room temperature to obtain a biochar-supported cobalt ferrite magnetic composite catalytic material, namely CoFe2O4@WT-450 catalytic material.

[0081] Example 3 The preparation method of biochar-supported cobalt ferrite magnetic composite catalytic material is carried out according to the following steps: Step 1: Green tea was selected as the biomass precursor and the carrier was pretreated by WT.

[0082] Green tea is an unfermented tea with a polyphenol content of 40 wt% and a catechin content of 25 wt%.

[0083] Green tea was soaked in deionized water at 100℃ for 2.5 hours at a solid-liquid ratio of 1g:60mL to simulate daily use. After filtration, tea residue was obtained. The tea residue was dried at 110℃, then pulverized and passed through a 100-mesh sieve to obtain WT.

[0084] Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0085] Step 2.1, prepare the suspension.

[0086] Weigh out Co(NO3)2·6H2O and Fe(NO3)3·9H2O according to a Co / Fe molar ratio of 1:2, and mix Co(NO3)2·6H2O and Fe(NO3)3·9H2O to form a metal salt; The metal salt was dispersed with pretreated WT in deionized water and subjected to ultrasonic treatment for 35 minutes to obtain a suspension. The metal salt accounted for 35% of the mass of the pretreated WT.

[0087] The solid mass of the metal salt and the pretreated WT was 1 g: 8 mL in liquid-solid ratio with deionized water.

[0088] Step 2.2, prepare solid product.

[0089] The suspension was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 170°C for 12 hours to obtain a solid product.

[0090] Step 2.3: Prepare the dried precursor.

[0091] The solid product was washed with deionized water and dried at 65°C to obtain the dried precursor.

[0092] Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0093] The dried precursor was placed in a muffle furnace and heated to the target temperature of 750℃ at a rate of 7℃ / min. Pyrolysis activation was performed at the target temperature for 100 min, followed by cooling to room temperature to obtain a biochar-supported cobalt ferrite magnetic composite catalytic material, namely CoFe2O4@WT-750 catalytic material.

[0094] Example 4 The preparation method of biochar-supported cobalt ferrite magnetic composite catalytic material is carried out according to the following steps: Step 1: Green tea was selected as the biomass precursor and the carrier was pretreated by WT.

[0095] Green tea is an unfermented tea, with a polyphenol content of 30 wt% and a catechin content of 20 wt%.

[0096] Green tea was soaked in deionized water at 90℃ for 2 hours at a solid-liquid ratio of 1g:50mL to simulate daily use. After filtration, tea residue was obtained. The tea residue was dried at 100℃, then pulverized and passed through a 100-mesh sieve to obtain WT.

[0097] Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0098] Step 2.1, prepare the suspension.

[0099] Weigh out Co(NO3)2·6H2O and Fe(NO3)3·9H2O at a Co / Fe molar ratio of 1:2, and mix them to form a metal salt; the mass of the metal salt accounts for 30% of the pretreated WT mass.

[0100] The metal salt and pretreated WT were dispersed in deionized water and subjected to ultrasonic treatment within 30 minutes to obtain a suspension.

[0101] The solid mass of the metal salt and the pretreated WT was 1 g:7 mL in liquid-solid ratio with deionized water.

[0102] Step 2.2, prepare solid product.

[0103] The suspension was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 160°C for 10 hours to obtain a solid product.

[0104] Step 2.3: Prepare the dried precursor.

[0105] The solid product was washed with deionized water and dried at 60°C to obtain the dried precursor.

[0106] Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

[0107] The dried precursor was placed in a muffle furnace and heated to the target temperature of 500℃ at a rate of 6℃ / min. Pyrolysis activation was performed at the target temperature for 90 min, followed by cooling to room temperature to obtain a biochar-supported cobalt ferrite magnetic composite catalytic material, namely CoFe2O4@WT-500 catalytic material.

[0108] Example 5 A magnetic composite catalytic material for cobalt ferrite supported on biochar was obtained using the same preparation method as that for cobalt ferrite supported on biochar.

[0109] Example 6 Application of biochar-supported cobalt ferrite magnetic composite catalytic materials in advanced oxidation technologies for water treatment.

Claims

1. A method for preparing a magnetic composite catalytic material of cobalt ferrite supported on biochar, characterized in that, The specific steps are as follows: Step 1: Green tea was selected as a biomass precursor and subjected to carrier WT pretreatment. Step 2: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar; Step 2.1, prepare the suspension; Step 2.2, prepare the solid product; Step 2.3: Prepare the dried precursor; Step 2.4: Prepare a magnetic composite catalytic material of cobalt ferrite supported on biochar.

2. The method for preparing the magnetic composite catalytic material of biochar supported cobalt ferrite according to claim 1, characterized in that, In step 1, the green tea is unfermented tea with a polyphenol content of 15wt%~40wt% and a catechin content of 10wt%~25wt%.

3. The method for preparing the magnetic composite catalytic material of biochar-supported cobalt ferrite according to claim 1, characterized in that, In step 1, green tea is soaked in deionized water at 80-100℃ for 1.5-2.5 hours at a solid-liquid ratio of 1g:(40-60)mL, and then filtered to obtain tea residue. The tea dregs are dried at 100-110℃, then crushed and passed through a 100-mesh sieve to obtain WT.

4. The method for preparing the magnetic composite catalytic material of biochar supported on cobalt ferrite according to claim 1, characterized in that, In step 2.1, Co(NO3)2·6H2O and Fe(NO3)3·9H2O are weighed according to a Co / Fe molar ratio of 1:(1.8-2.2), and Co(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed to form a metal salt; The metal salt and pretreated WT were dispersed in deionized water and subjected to ultrasonic treatment for 25-35 minutes to obtain a suspension; the mass of the metal salt accounted for 25%-35% of the mass of the pretreated WT. The solid mass of the metal salt and the pretreated WT was compared with the liquid-solid ratio of deionized water at a ratio of 1 g: (6-8) mL.

5. The method for preparing the magnetic composite catalytic material of biochar supported on cobalt ferrite according to claim 1, characterized in that, In step 2.2, the suspension is transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 150-170°C for 8-12 hours to obtain a solid product.

6. The method for preparing the magnetic composite catalytic material of biochar supported on cobalt ferrite according to claim 1, characterized in that, In step 2.3, the solid product is washed with deionized water and dried at 55-65°C to obtain the dried precursor.

7. The method for preparing the magnetic composite catalytic material of biochar supported on cobalt ferrite according to claim 1, characterized in that, In step 2.4, the dried precursor is placed in a muffle furnace and heated to the target temperature at a rate of 3-7℃ / min, the target temperature being 450-750℃. The material was pyrolyzed and activated at the target temperature for 80-100 minutes, and then cooled to room temperature to obtain a magnetic composite catalytic material of cobalt ferrite supported on biochar.

8. The method for preparing the magnetic composite catalytic material of biochar-supported cobalt ferrite according to claim 7, characterized in that, The target temperature is any one of 500℃, 600℃, and 700℃.

9. A magnetic composite catalytic material with biochar supported on cobalt ferrite, characterized in that, The magnetic composite catalytic material is obtained by any of the preparation methods of biochar-supported cobalt ferrite as described in any of claims 1-8.

10. The application of a magnetic composite catalytic material with biochar-supported cobalt ferrite, characterized in that, Application of biochar-supported cobalt ferrite magnetic composite catalytic materials in advanced oxidation technologies for water treatment.

Images