Method for preparing modified sludge biochar from boron carbide and application of modified sludge biochar in selective degradation of organic pollutants
By using the mixing and pyrolysis treatment of boron carbide and dry sludge, efficient boron carbide modified sludge biochar was prepared, which solved the problem of low catalytic performance of existing sludge biochar, and achieved efficient degradation of organic pollutants and reusable materials.
Patent Information
- Application Number
- CN202411803110.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2025-03-14
AI Technical Summary
The existing sludge biochar has low catalytic performance, insufficient anti-interference ability, and it is difficult to effectively degrade organic pollutants. The boron dopant used is boric acid, which is not conducive to transportation and recycling.
Boron carbide is used as the boron dopant, and through mixing and pyrolysis treatment with dry sludge, boron carbide modified sludge biochar is prepared as a persulfate activator for selective degradation of organic pollutants.
The catalytic activity and selective degradation ability of sludge biochar are improved, and efficient degradation of organic pollutants such as rhodamine B is achieved. The materials can be reused and are environmentally friendly.
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Figure CN119608198A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of solid waste treatment and water purification environmental protection, and relates to a method for preparing modified sludge biochar by utilizing boron carbide and an application thereof in selectively degrading organic pollutants. Background Art
[0002] In recent years, biological treatment technologies represented by activated sludge processes have been widely used in urban and industrial wastewater treatment. However, the operation of the activated sludge process will produce a large amount of residual sludge. How to treat and dispose of it in a green, efficient and harmless manner has become an important problem that needs to be solved urgently in my country. Reusing the residual sludge from sewage treatment plants to prepare water treatment catalysts provides a new solution for the resource utilization of sludge. Studies have shown that preparing sludge into biochar has a high catalytic activity for the activation of persulfate. For example, Wang H et al. used a pyrolysis method to prepare landfill sludge into biochar in Applied Catalysis B: Environmental, Vol. 279, 2020, p. 119361, and found that the prepared sludge biochar can efficiently activate persulfate to degrade bisphenol A. However, due to the low anti-interference ability and lack of catalytic sites of the original sludge biochar, its catalytic performance still needs to be further improved. Finding a green and efficient sludge biochar modification method has become a current research hotspot.
[0003] The catalytic activity of biochar can be effectively improved by changing its specific structural defects, pore structure and surface functional groups. It is worth mentioning that doping heteroatoms (such as N, B and S) into biochar can change the surface charge distribution of biochar materials, thereby increasing its active sites, defect level and electron transfer ability, thereby improving the catalytic activity of biochar. Compared with nitrogen atom doping and sulfur atom doping, boron atom doping is a more ideal doping method. Since the electronegativity of boron (χB=2.01) is lower than that of carbon (χC=2.55), and the atomic size is similar to that of carbon, the Fermi level of boron atoms is lower and it is easier to donate electrons. During the boron doping process, the polarization of carbon attracts electrons from boron to carbon, making the boron atoms positively charged. Therefore, boron dopants (such as C-Bσ bonds and BCO) can be used as active sites for adsorption and activation of negatively charged persulfates. Liu B et al., Chemical Engineering Journal, Vol. 396, p. 125119, 2020, Chen C et al., Chemosphere, Vol. 301, p. 134690, 2022, and Pan G et al., Journal of Hazardous Materials, Vol. 445, p. 130479, 2023, prepared boron-doped biochar using tea seed shells, garden waste, and wheat straw with boric acid under pyrolysis conditions. The above materials can efficiently activate persulfate to promote the oxidative degradation of pollutants. However, whether the wastewater plant residual sludge can be used as a biochar raw material to prepare an efficient boron-doped biochar catalyst needs further investigation. In addition, the boron doping agents used in previous studies were all boric acid, which is not conducive to transportation and recycling. As a green, reusable new material, boron carbide (B4C) has extremely high hardness and excellent thermoelectric / mechanical properties. Zhou P et al. confirmed in Green Energy & Environment, Vol. 5, pp. 414-422, 2020 that B4C can promote Fenton-like reactions by accelerating the conversion rate of Fe(III) / Fe(II). In view of this, it is worthwhile to further study the use of boron carbide instead of boric acid as a biochar modifier for the preparation of boron-doped sludge biochar and the activation of persulfate to catalyze the oxidative degradation of pollutants.
[0004] The present invention uses boron carbide as a boron doping agent to prepare boron-doped sludge biochar, which is simple, clean, low-cost and environmentally friendly. The synthesized boron carbide sludge biochar can be used as a persulfate activator to achieve selective degradation of organic pollutants such as rhodamine B. Summary of the invention
[0005] The present invention provides a method for preparing boron carbide modified sludge biochar by utilizing boron carbide doped residual sludge, aiming at preparing a low-cost and environmentally friendly novel high-efficiency persulfate advanced oxidation catalyst for selectively degrading organic pollutants in wastewater and realizing resource utilization of sludge.
[0006] The technical solution of the present invention:
[0007] A method for preparing modified sludge biochar using boron carbide, the steps are as follows:
[0008] Step 1: Sludge pretreatment: Collect the residual sludge after compression in the secondary sedimentation tank of the sewage treatment plant, wash it with deionized water 2-3 times and filter it, dry the filtered sludge at 100-110℃ for more than 24h, then crush it with a crusher and pass it through a 200-mesh sieve, and collect the sieved dry sludge;
[0009] Step 2: Mixing boron carbide and dry sludge: Mix the dry sludge obtained in step 1 with boron carbide in a mass ratio of 1:1 to 5:1, and stir at room temperature for more than 24 hours to obtain a mixture of boron carbide and dry sludge; filter the mixture of boron carbide and dry sludge through a 5 μm microporous filter membrane, and dry it again at a temperature of 100-110° C. for more than 24 hours to constant weight, and then pass the mixture of boron carbide and dry sludge through a 200-mesh sieve for standby use;
[0010] Step 3: Preparation of modified sludge biochar prepared by boron carbide: The boron carbide and dry sludge mixture prepared in step 2 is pyrolyzed at 300-600°C for 2 h at a heating rate of 10°C / min under vacuum and N2 atmosphere. After cooling to room temperature, it is ground and sieved through 200 and 500 mesh sieves in turn to obtain boron carbide modified sludge biochar.
[0011] Boron carbide modified sludge biochar was used as a catalyst in the persulfate advanced oxidation reaction to degrade organic pollutants. The steps are as follows:
[0012] Step 1: adding boron carbide modified sludge biochar to ultrapure water to obtain a boron-doped sludge biochar suspension; ultrasonically treating the boron-doped sludge biochar suspension (8 g / L) for more than 20 minutes;
[0013] Step 2: prepare persulfate stock solution (160 mM);
[0014] Step 3: Prepare 50 μM solutions of organic pollutants such as rhodamine B, methylene blue, phenol, sulfonamide, bisphenol A and benzoic acid.
[0015] Step 4: Add the boron-doped sludge biochar suspension obtained in step 1 and the persulfate mother liquor obtained in step 2 to the organic pollutant solution obtained in step 3, so that the boron-doped sludge biochar concentration is 0.4 g / L and the persulfate concentration is 0.8 mM; place the reaction system on a magnetic stirrer (400 rpm) to react (under normal temperature conditions), take samples at regular intervals, and measure the residual concentration of organic pollutants in the system. The concentrations of rhodamine B and methylene blue are detected by UV-visible spectrophotometer, and phenol, sulfonamide, bisphenol A and benzoic acid are detected by high performance liquid chromatography.
[0016] Beneficial effects of the present invention: The modified sludge biochar of the present invention is prepared by pyrolysis of boron carbide and dry sludge at an initial mass ratio of 1:1 to 5:1 at 300-600°C for 2 hours after the special treatment in step 2. The preparation process is simple and the reaction conditions are mild. The synthesized material can be used to catalyze the advanced oxidation reaction of persulfate, has high catalytic efficiency and good reuse rate, can achieve selective degradation of organic pollutants, and can also provide a new solution for the resource utilization of sludge. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a scanning electron microscope image of boron carbide-modified sludge biochar prepared at an initial mass ratio of boron carbide to sludge of 2:1 and a pyrolysis temperature of 600°C.
[0018] Figure 2 Boron carbide modified sludge biochar (xSBC) is prepared by changing the initial mass ratio of boron carbide to sludge and the pyrolysis temperature. T , x is the initial mass ratio of boron carbide to sludge; T is the pyrolysis temperature), where a is SBC 600 ; b is 1B-SBC 600 ; c is 3B-SBC 600 ; d is 2B-SBC 300 ; e is 2B-SBC 450 .
[0019] Figure 3 is the X-ray diffraction pattern of boron carbide modified sludge biochar, where a is 1B-SBC 600 、2B-SBC 600 and 3B-SBC 600 X-ray diffraction pattern of b; b is 2B-SBC 300 、2B-SBC 450 and 2B-SBC 600 X-ray diffraction pattern of .
[0020] Figure 4 The catalytic activity of boron carbide modified sludge biochar materials in the degradation of rhodamine B by activated persulfate.
[0021] Figure 5 The degradation of Rhodamine B by activating persulfate catalysis by using sludge biochar materials modified with different boron carbides was carried out, wherein a is the effect of sludge biochar materials prepared with different initial mass ratios of boron carbide to sludge on the degradation of Rhodamine B, and b is the effect of the pyrolysis temperature of the modified sludge biochar materials on the degradation of Rhodamine B.
[0022] Figure 6 Is to use 2B-SBC 600 Activated persulfate degrades methylene blue, phenol, sulfonamide, bisphenol A and benzoic acid.
[0023] Figure 7 Is a comparison of SBC 600 and 2B-SBC 600 Recyclability of activated persulfate-degraded rhodamine B. DETAILED DESCRIPTION
[0024] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.
[0025] Example 1
[0026] Preparation of Boron Carbide Modified Sewage Sludge Biochar:
[0027] (1) Preparation method of modified sludge biochar with different boron carbide contents:
[0028] Step 1: Sludge pretreatment: Collect the residual sludge after compression in the secondary sedimentation tank of the sewage treatment plant, wash it with deionized water three times and filter it, put the filtered sludge into a tray and dry it in an electric blast drying oven (105°C) for 24 hours, then crush it with a grinder and pass it through a 200-mesh sieve, collect the sieved dry sludge for later use.
[0029] Step 2: Mixing of boron carbide and sludge: Weigh 10g of the dry sludge ground in step 1, mix it with boron carbide in a 50mL conical flask, the mass ratio of boron carbide to sludge is 1:1, 2:1 and 3:1 respectively, and stir magnetically at 25°C for 24h. After completion, the mixture of boron carbide and sludge is filtered through a 5μm microporous filter membrane, and then placed in an electric heated blast drying oven (105°C) for drying for 24h, and then the mixture of boron carbide and sludge is sieved through a 200-mesh sieve for standby use.
[0030] Step 3: Preparation of boron carbide modified sludge biochar: The mixture of boron carbide and sludge obtained in step 2 was placed in a quartz boat in a vacuum tube furnace, and pyrolyzed at 600°C for 2 hours at a heating rate of 10°C / min under a N2 atmosphere. After cooling to room temperature, it was ground with a mortar and passed through 200 and 500 mesh sieves in turn to obtain boron carbide modified sludge biochar.
[0031] (2) Preparation of boron carbide modified sludge biochar at different pyrolysis temperatures:
[0032] Step 1: The sludge pretreatment step is the same as step 1 in Example 1 (1).
[0033] Step 2: Weigh 10 g of the dry sludge ground in step 1, mix it with boron carbide in a 50 mL conical flask, the mass ratio of boron carbide to sludge is 2:1, and stir magnetically at 25°C for 24 hours. After completion, filter the mixture of boron carbide and sludge through a 5 μm microporous filter membrane, put it into an electric blast drying oven (105°C) for drying for 24 hours, and then pass the mixture of boron carbide and sludge through a 200 mesh sieve for standby use.
[0034] Step 3: Preparation of boron carbide modified sludge biochar: The mixture of boron carbide and sludge obtained in step 2 was placed in a quartz boat, placed in a vacuum tube furnace, and pyrolyzed at 300, 450 and 600 °C for 2 h at a heating rate of 10 °C / min under N2 atmosphere. After cooling to room temperature, it was ground with a mortar and passed through 200 and 500 mesh sieves in turn to obtain boron carbide modified sludge biochar.
[0035] Figure 1 This is a scanning electron microscope image of boron carbide-modified sludge biochar prepared at an initial mass ratio of boron carbide to sludge of 2:1 and a pyrolysis temperature of 600°C. Figure 2 Boron carbide modified sludge biochar (xSBC) is prepared by changing the initial mass ratio of boron carbide to sludge and the pyrolysis temperature. T , x is the initial mass ratio of boron carbide to sludge; T is the pyrolysis temperature), where (a) is SBC 600 ; (b) is 1B-SBC 600 ; (c) 3B-SBC 600 ; (d) is 2B-SBC 300 ; (e) is 2B-SBC 450 The results show that the boron carbide modified biochar has a relatively smooth irregular structure. With the increase of the boron carbide doping ratio, the layered structure on its surface gradually becomes less and smoother. With the increase of the pyrolysis temperature, the biochar gradually becomes loose and an irregular pore structure gradually appears.
[0036] Figure 3(a) is the X-ray diffraction pattern of the modified sludge biochar with different boron carbide contents in Example 1, and (b) is the X-ray diffraction pattern of the modified sludge biochar at different pyrolysis temperatures in Example 1. The results show that the formed boron carbide modified sludge biochar has diffraction peaks representing boron carbide at 2θ=19.7°, 22.0°, 23.5°, 31.9°, 35.0°, 37.8° and 66.8°, and a characteristic diffraction peak representing graphite carbon at 2θ=26.5°, confirming that boron carbide is successfully doped into the biochar structure.
[0037] Example 2
[0038] Comparison of catalytic performance of persulfate degradation of Rhodamine B by boron carbide modified sludge biochar:
[0039] Step 1: Add 20 mg of boron carbide and raw sludge biochar SBC to 2.5 mL of ultrapure water 600 (pyrolysis temperature is 600℃) or boron carbide modified sludge biochar 2B-SBC 600 (The initial mass ratio of boron carbide to sludge is 2:1; the pyrolysis temperature is 600°C) to obtain a boron carbide or sludge biochar suspension. The suspension is placed in an ultrasonic cleaner (100W) for more than 20 minutes to improve its dispersibility.
[0040] Step 2: Add 20 mg of boron carbide and 20 mg of original sludge biochar SBC to 2.5 mL of ultrapure water. 600 A suspension of a mixture of boron carbide and sludge biochar was obtained. The suspension was placed in an ultrasonic cleaner (100 W) for more than 20 minutes to improve its dispersibility.
[0041] Step 3: Weigh 9.84 g of potassium persulfate into a 100 mL volumetric flask and fully dissolve to obtain a potassium persulfate mother solution with a concentration of 160 mM.
[0042] Step 4: Weigh 24.0 mg of Rhodamine B and dilute it to a 1 L volumetric flask to obtain a Rhodamine B solution with a concentration of 50 μM.
[0043] Step 5: Take 47.25 mL of the pollutant solution in step 3, add the suspension obtained in step 1 or step 2 and 0.25 mL of the potassium persulfate mother solution obtained in step 2. Place the reaction system on a magnetic stirrer (400 rpm) for reaction.
[0044] Step 5: Regularly draw about 1 mL of sample with a syringe, dilute it to 2 mL with ultrapure water, pass it through a 0.22 μm water film, and measure the residual concentration of Rhodamine B in the system with a UV-visible spectrophotometer.
[0045] The experimental results are as follows Figure 4As shown in the figure, the boron carbide modified sludge biochar can achieve complete degradation of rhodamine B within 60 minutes, which is much higher than other control systems. 600 The degradation rates of rhodamine B in the catalytic system were higher than those of persulfate and SBC alone. 600 , B4C and SBC 600 The +B4C system was 51.1%, 56.8%, 64.1% and 69.8% higher. The above results show that boron carbide modified sludge biochar can promote the degradation of rhodamine B in a persulfate activated advanced oxidation system and can be used to treat organic pollutants such as rhodamine B in wastewater.
[0046] Example 3
[0047] Degradation of Rhodamine B by persulfate activated by boron carbide modified sludge biochar prepared under different conditions:
[0048] Step 1: Add 20 mg of boron carbide modified sludge biochar (xSBC) to 2.5 mL of ultrapure water. T , x is the initial mass ratio of boron carbide to sludge; T is the pyrolysis temperature), and a sludge biochar suspension is obtained. The suspension is placed in an ultrasonic cleaner (100W) for more than 20 minutes to improve its dispersibility.
[0049] Step 2: Weigh 9.84 g of potassium persulfate into a 100 mL volumetric flask and fully dissolve to obtain a potassium persulfate mother solution with a concentration of 160 mM.
[0050] Step 3: Weigh 24.0 mg of Rhodamine B and dilute it to a 1 L volumetric flask to obtain a Rhodamine B solution with a concentration of 50 μM.
[0051] Step 4: Take 47.25 mL of the pollutant solution in step 3, add the boron-doped sludge biochar suspension obtained in step 1 and 0.25 mL of potassium persulfate mother solution obtained in step 2. Place the reaction system on a magnetic stirrer (400 rpm) for reaction.
[0052] Step 5: Regularly draw about 1 mL of sample with a syringe, dilute it to 2 mL with ultrapure water, pass it through a 0.22 μm water film, and measure the residual concentration of Rhodamine B in the system with a UV-visible spectrophotometer.
[0053] The experimental results are as follows Figure 5 As shown in a, the modified sludge biochar with different boron carbide contents can degrade more than 90% of rhodamine B within 90 min, which is much higher than the degradation rate of rhodamine B in the advanced oxidation system of monopersulfate (51.1%). 600 The most favorable oxidative degradation of rhodamine B, after 90 min of reaction, 2B-SBC 600The catalytic system can achieve complete degradation of Rhodamine B, and its degradation rate is higher than that of 1B-SBC 600 and 3B-SBC 600 The catalytic system was 0.5% and 6.3% higher. Figure 5 As shown in (b), the pyrolysis temperature of the modified sludge biochar directly affects its catalytic activity. When the pyrolysis temperature was reduced from 600°C to 300 and 450°C, the degradation rate of Rhodamine B decreased from 100% to 71.4% and 75.8% after 90 min of reaction.
[0054] The above results show that the doping amount of boron carbide and the pyrolysis temperature of modified sludge biochar can affect its catalytic activity in the degradation of rhodamine B by activated persulfate. The boron carbide modified sludge biochar prepared under the conditions of an initial mass ratio of boron carbide to sludge of 2:1 and a pyrolysis temperature of 600℃ has the highest catalytic activity.
[0055] Example 4
[0056] Selective degradation of organic pollutants by persulfate activated by boron carbide modified sludge biochar:
[0057] Step 1: Add 20 mg of boron carbide-modified sludge biochar to 2.5 mL of ultrapure water to obtain a sludge biochar suspension. The initial mass ratio of boron carbide to sludge during biochar preparation was 2:1, and the pyrolysis temperature was 600 ° C. The suspension was placed in an ultrasonic cleaner (100 W) for 20 min to improve its dispersibility.
[0058] Step 2: Weigh 9.84 g of potassium persulfate into a 100 mL volumetric flask and fully dissolve to obtain a potassium persulfate mother solution with a concentration of 160 mM.
[0059] Step 3: Prepare stock solutions of organic pollutants such as methylene blue, phenol, sulfonamide, bisphenol A and benzoic acid at a concentration of 50 μM.
[0060] Step 4: Take 47.25 mL of the different pollutant solutions in step 3 respectively, add the boron-doped sludge biochar suspension obtained in step 1 and 0.25 mL of potassium persulfate mother solution obtained in step 2. Place the reaction system on a magnetic stirrer (400 rpm) for reaction.
[0061] Step 5: Regularly draw about 1 mL of sample with a syringe and dilute it to 2 mL with ultrapure water. After passing through a 0.22 μm water film, measure the residual concentration of organic pollutants in the system. The concentration of methylene blue is detected by UV-visible spectrophotometer, and phenol, sulfonamide, bisphenol A and benzoic acid are detected by high performance liquid chromatography.
[0062] The experimental results are as follows Figure 6As shown in the figure, after 90 minutes of reaction, the degradation rates of methylene blue, phenol, sulfonamide, bisphenol A and benzoic acid in the system catalyzed by boron carbide modified sludge biochar were 100%, 88.4%, 100%, 96.1% and 14.4%, respectively. The results show that boron carbide modified sludge biochar has the ability to selectively degrade organic pollutants, has less interference with water bodies, and is more conducive to treating wastewater with complex components.
[0063] Example 5
[0064] Recyclability of boron carbide modified sewage sludge biochar for degradation of rhodamine B
[0065] Step 1: Add 20 mg of boron carbide-modified sludge biochar to 2.5 mL of ultrapure water. The initial mass ratio of boron carbide to sludge during biochar preparation is 2:1, and the pyrolysis temperature is 600 ° C to obtain a boron-doped sludge biochar suspension. The suspension is placed in an ultrasonic cleaner (100 W) for 20 min to improve its dispersibility.
[0066] Step 2: Weigh 9.84 g of potassium persulfate into a 100 mL volumetric flask and fully dissolve to obtain a potassium persulfate mother solution with a concentration of 160 mM.
[0067] Step 3: Weigh 24.0 mg of Rhodamine B and dilute it to a 1 L volumetric flask to obtain a Rhodamine B solution with a concentration of 50 μM.
[0068] Step 4: Take 50 mL of the rhodamine B solution in step 3, add the boron-doped sludge biochar suspension obtained in step 1 and 0.25 mL of the potassium persulfate mother solution obtained in step 2. Place the reaction system on a magnetic stirrer (400 rpm) for reaction.
[0069] Step 5: Regularly draw about 1 mL of sample with a syringe, dilute it to 2 mL with ultrapure water, pass it through a 0.22 μm water film, and measure the residual concentration of Rhodamine B in the system with a UV-visible spectrophotometer.
[0070] Step 6: A system catalyzed by 20 mg of original biochar (biochar pyrolysis temperature of 600°C) without boron carbide was used as a control group, and other experimental conditions were the same as above.
[0071] Step 7: After the reaction was carried out for 90 min, the concentrations of rhodamine B and potassium persulfate in the system were supplemented to 25 mg / L and 0.8 mM, respectively, on a magnetic stirrer (400 rpm), and step 5 was repeated to continue the next round of degradation experiment, which was repeated for a total of 4 cycles.
[0072] The experimental results are as follows Figure 7As shown in the figure, in the system catalyzed by the original biochar, the degradation rate of rhodamine B decreased to 81.9% after four cycles. In the system catalyzed by the boron carbide-modified sludge biochar, the degradation efficiency of sulfonamide after the first, second, third and fourth cycles was 100%, 100%, 99.6% and 95.3%, respectively. This shows that the effect of boron carbide-modified sludge biochar catalyzing the degradation of rhodamine B is stable and can be repeatedly used in the treatment of organic pollutants in wastewater.
Claims
1. A method for preparing modified sludge biochar using boron carbide, characterized in that: Here are the steps: Step 1: Sludge pretreatment: Collect the residual sludge after compression in the secondary sedimentation tank of the sewage treatment plant, wash it with deionized water 2-3 times and filter it, dry the filtered sludge at 100-110℃ for more than 24h, then crush it with a crusher and pass it through a 200-mesh sieve, and collect the sieved dry sludge; Step 2: Mixing boron carbide and dry sludge: Mix the dry sludge obtained in step 1 with boron carbide in a mass ratio of 1:1 to 5:1, and stir at room temperature for more than 24 hours to obtain a mixture of boron carbide and dry sludge; filter the mixture of boron carbide and dry sludge through a 5 μm microporous filter membrane, and dry it again at a temperature of 100-110° C. for more than 24 hours to constant weight, and then pass the mixture of boron carbide and dry sludge through a 200-mesh sieve for standby use; Step 3: Preparation of modified sludge biochar prepared by boron carbide: The boron carbide and dry sludge mixture prepared in step 2 is pyrolyzed at 300-600°C for 2 h at a heating rate of 10°C / min under vacuum and N2 atmosphere. After cooling to room temperature, it is ground and sieved through 200 and 500 mesh sieves in turn to obtain boron carbide modified sludge biochar.
2. The use of boron carbide modified sludge biochar obtained by the method according to claim 1 as a catalyst in the degradation of organic pollutants by persulfate advanced oxidation reaction, characterized in that: Here are the steps: Step 1: adding boron carbide modified sludge biochar into ultrapure water to obtain a boron-doped sludge biochar suspension; ultrasonically treating the boron-doped sludge biochar suspension for more than 20 minutes; Step 2: preparing persulfate mother liquor; Step 3: Prepare a 50 μM organic pollutant solution; Step 4: Add the boron-doped sludge biochar suspension obtained in step 1 and the persulfate mother liquor obtained in step 2 to the organic pollutant solution obtained in step 3, so that the concentration of boron-doped sludge biochar is 0.4 g / L and the concentration of persulfate is 0.8 mM; place the reaction system on a magnetic stirrer to react at room temperature, take samples at regular intervals, and measure the residual concentration of organic pollutants in the system.
3. The use according to claim 2, characterized in that: The concentration of the boron-doped sludge biochar suspension is 8 g / L.
4. The use according to claim 2, characterized in that: The concentration of the persulfate mother solution is 160 mM.
5. The use according to claim 2, characterized in that: The organic pollutants are rhodamine B, methylene blue, phenol, sulfonamide, bisphenol A and benzoic acid.