Preparation of activated carbon composite particles and method for degrading sulfamethoxazole in wastewater by using activated carbon composite particles

Abstract

The invention discloses a preparation method of activated carbon composite particles and a method for degrading sulfamethoxazole in wastewater by the activated carbon composite particles, and the preparation method comprises the following steps: step (1), dissolving soluble trivalent iron salt in ultrapure water and carrying out ultrasonic oscillation to obtain a trivalent iron solution; (2) soaking and cleaning the activated carbon particles with a hydrochloric acid solution, methanol and ultrapure water in sequence, and drying to obtain pretreated activated carbon particles; (3) adding the pretreated activated carbon particles into a ferric iron solution for oscillation treatment; taking out, washing with ultrapure water, and drying to obtain the activated carbon composite particles. The wastewater degradation method comprises the following steps: adding the prepared activated carbon composite particles and peroxymonosulfate into wastewater containing sulfamethoxazole together for degradation. The method solves the problems of low degradation efficiency, secondary pollution and the like when activated carbon and ferric iron are directly used for degrading sulfamethoxazole in wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of antibiotic degradation in wastewater. Specifically, it is a method for preparing activated carbon composite particles and degrading sulfamethoxazole in wastewater. Background Art

[0002] Antibiotics are chemical substances produced by microorganisms or higher animals and plants that can inhibit or kill other microorganisms, and have been widely used in preventing and treating human and animal diseases. China is a major producer and consumer of antibiotics. Sulfamethoxazole (SMX) has been used to prevent and treat bacterial infectious diseases due to its stable chemical properties, low price, broad antibacterial spectrum, convenient use, etc., and is widely used in fields such as animal husbandry, aquaculture, and the pharmaceutical industry. As one of the most produced and used types of antibiotics in the world, SMX is used in large quantities and widely, but it cannot be completely digested and absorbed by organisms. The residual part may be discharged into the environment in various ways such as sewage discharge, feces and urine, and surface infiltration, thereby destroying the ecological environment and causing serious harm to the human body. Traditional sewage treatment plants do not have dedicated treatment units to remove these sulfonamide compounds, and the removal effect is not good, resulting in antibiotics entering the natural environment without being completely degraded into small molecules, and being frequently detected in the water environment.

[0003] In the existing treatment methods, advanced oxidation technologies (AOPs) have been widely used due to their significant advantages such as high stability and high efficiency, and have also become one of the key research directions in recent years. At present, there have been many studies on the removal of antibiotics by activating persulfate with carbon materials. Among them, activated carbon (AC), as one of the most widely used non-metal catalysts for activating persulfate, has the advantages of low cost, developed porous structure, large specific surface area, and rich functional groups. In addition, iron-based materials have been widely used in the environmental pollution remediation of activating persulfate due to their low cost, environmental friendliness, and relative non-toxicity. However, the surface of activated carbon is prone to inactivation when activating persulfate, and the degradation rate of the method of using activated carbon alone to activate persulfate is not high, and iron-based materials will cause secondary pollution when exposed to the environment for a long time. Therefore, it is difficult for the existing technology to provide effective means for degrading antibiotics in water while ensuring ecological safety. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a method for preparing activated carbon composite particles with activity for activating peroxymonosulfate (PMS) to degrade sulfamethoxazole and a method for degrading sulfamethoxazole in wastewater.

[0005] To solve the above technical problems, the present invention provides the following technical solutions: A method for preparing activated carbon composite particles, comprising the following steps: Step (1), preparation of ferric iron solution: Dissolve soluble ferric iron salt in ultrapure water and ultrasonically vibrate to obtain ferric iron solution; Step (2), pretreatment of activated carbon particles: Soak and wash activated carbon particles successively with hydrochloric acid solution, methanol and ultrapure water, and perform drying treatment after the washing is completed. After the drying treatment is completed, pretreated activated carbon particles are obtained; Step (3), preparation of activated carbon composite particles: Add pretreated activated carbon particles into the ferric iron solution for vibration treatment; After the vibration treatment, take out and wash with ultrapure water, and perform drying treatment after the washing. After the drying treatment is completed, activated carbon composite particles are obtained.

[0006] The activated carbon composite particles prepared by the present invention using ferric iron modified spherical pretreated activated carbon particles have a significantly improved degradation effect on sulfamethoxazole, an antibiotic in wastewater, when combined with peroxymonosulfate compared with the pretreated activated carbon particles before modification; compared with Fe 2+ In comparison, the present invention uses Fe 3+ modified spherical pretreated activated carbon particles, which can effectively avoid the quenching reaction between a large amount of SO4 •- and •OH - with Fe 2+ and further improve its activation effect on peroxymonosulfate (PMS).

[0007] In the above preparation method of activated carbon composite particles, in step (1), the soluble ferric iron salt is one or a mixture of two or more of ferric nitrate, ferric nitrate hydrate, ferric chloride, ferric chloride hydrate, ferric sulfate or ferric sulfate hydrate. Compared with other soluble ferric iron salts, the activated carbon composite particles prepared using ferric nitrate have the least influence on the reaction system during the degradation of wastewater, and are more conducive to improving the degradation effect of PMS on sulfamethoxazole in wastewater.

[0008] In the above preparation method of activated carbon composite particles, in step (1), the conditions of ultrasonic vibration are: ultrasonic vibration at a frequency of 20 - 40 kHz for 5 - 10 min at room temperature. Under this ultrasonic vibration condition, the ferric iron salt can be uniformly dissolved in water, which is beneficial to better loading the ferric iron salt on the activated carbon later; the molar concentration of ferric iron in the ferric iron solution is 0.07 - 0.09 mol / L.

[0009] For the preparation method of the above-mentioned activated carbon composite particles, in step (2), the molar concentration of the hydrochloric acid solution is 0.1 - 0.2 mmol / L; the soaking time of the activated carbon particles in the hydrochloric acid solution is 18 - 24 h; the soaking time of the activated carbon particles in methanol is 0.5 - 1.5 h; the soaking time of the activated carbon particles in ultrapure water is 0.5 - 1.5 h. Soaking with a hydrochloric acid solution with a concentration of 0.1 - 0.2 mmol / L can effectively remove the dust and waste residues on the surface of the activated carbon particles and will not damage the structure of the activated carbon particles. Then, soaking with methanol is used to remove the residual hydrochloric acid solution on the activated carbon particles, and finally, soaking with ultrapure water is used to remove the residual methanol on the activated carbon particles. By performing the above cleaning pretreatment on the activated carbon particles, the dust and waste residues on the surface of the activated carbon particles can be effectively removed, which is beneficial for better loading of ferric salts in the subsequent steps.

[0010] For the preparation method of the above-mentioned activated carbon composite particles, in step (2), the diameter of the activated carbon particles is 8 - 10 mm (using activated carbon particles within this diameter range for the loading of ferric iron to prepare activated carbon composite particles has a better activation effect on PMS; if the diameter of the activated carbon particles exceeds this range, the activation effect of the finally prepared activated carbon composite particles on PMS will be significantly reduced); the drying treatment conditions are: 100 - 110 °C, 10 - 15 h. Under these drying treatment conditions, the moisture in the pretreated activated carbon particles can be effectively removed, and at the same time, the damage to its structure caused by overheating can be effectively avoided.

[0011] For the preparation method of the above-mentioned activated carbon composite particles, in step (1), the molar concentration of ferric iron in the ferric iron solution is 0.07 - 0.09 mol / L; in step (3), the mass-to-volume ratio of the pretreated activated carbon particles to the ferric iron solution is 1 g:(80 - 100) mL; when the mass-to-volume ratio of the pretreated activated carbon particles to the ferric iron solution with a concentration of 0.07 - 0.09 mol / L is within the above range, the activated carbon composite particles prepared have the best activation effect on PMS. If the mass-to-volume ratio of the two exceeds this range, the activation effect of the finally prepared activated carbon composite particles on PMS will be significantly reduced; this may be because when the mass-to-volume ratio of the two is within the above range, in the prepared activated carbon composite particles, the ratio between ferric iron and the pretreated activated carbon particles is more reasonable, which is conducive to the better cooperation between ferric iron and the pretreated activated carbon particles during the activation of PMS and the degradation of sulfamethoxazole, improving its activation ability for PMS, and thus improving the degradation efficiency of sulfamethoxazole.

[0012] When the activated carbon composite particles prepared by the present invention are combined with peroxymonosulfate to degrade sulfamethoxazole in wastewater, the mechanism of the synergistic effect of ferric iron and pretreated activated carbon particles is as follows: The activated carbon composite particles adsorb PMS onto their surface or into their micropores. Under the action of ferric iron Fe(III) loaded on the pretreated activated carbon particles, peroxymonosulfate can generate SO4 •- and •OH - and other reactive oxygen species (ROS); after the activation of peroxymonosulfate by ferric iron Fe(III), it is converted into ferrous iron Fe(II). The pretreated activated carbon particles, as an electron mediator, can accelerate the cycle between ferrous iron Fe(II) and ferric iron Fe(III), avoiding the inactivation of iron species (ensuring the stability of its ability to activate peroxymonosulfate), thereby accelerating the release of reactive oxygen species by peroxymonosulfate and further improving the degradation efficiency of sulfamethoxazole. At the same time, the combination of ferrous iron Fe(II) on the surface of the pretreated activated carbon particles can activate molecular oxygen to generate a superoxide anion ( 1 O2), which can accelerate the oxidation-reduction reaction of iron and further improve the activation effect of peroxymonosulfate.

[0013] In the preparation method of the above-mentioned activated carbon composite particles, in step (3), the conditions for the shaking treatment are: 20 - 30 °C, 150 - 200 rpm, 18 - 24 h; the conditions for the drying treatment are: 100 - 110 °C, 10 - 15 h.

[0014] In the preparation method of the above-mentioned activated carbon composite particles, in step (1), the soluble ferric salt is ferric nitrate nonahydrate, and the conditions for the ultrasonic shaking are: ultrasonic shaking at a frequency of 30 kHz for 5 min at room temperature; the molar concentration of ferric iron in the ferric iron solution is 0.074 mol / L; In step (2), the diameter of the activated carbon particles is 8 - 10 mm; the molar concentration of the hydrochloric acid solution is 0.1 mmol / L; the soaking time of the activated carbon particles in the hydrochloric acid solution is 24 h; the soaking time of the activated carbon particles in methanol is 1 h; the soaking time of the activated carbon particles in ultrapure water is 1 h; the conditions for the drying treatment are: 105 °C, 12 h; In step (3), the mass-to-volume ratio of the pretreated activated carbon particles to the ferric iron solution is 1 g: 100 mL; the conditions for the shaking treatment are: 25 °C, 180 rpm, 24 h; the conditions for the drying treatment are: 105 °C, 12 h.

[0015] A method for degrading sulfamethoxazole in wastewater, in which peroxymonosulfate and the activated carbon composite particles prepared by the preparation method of the above-mentioned activated carbon composite particles are added together to the wastewater containing sulfamethoxazole to degrade sulfamethoxazole in the wastewater.

[0016] In the above method for degrading sulfamethoxazole in wastewater, in the initial reaction system for degrading wastewater: the mass ratio of sulfamethoxazole to the activated carbon composite particles is 1:(700-900), and the molar ratio of sulfamethoxazole to peroxymonosulfate is 1:(7-10); the pH of the initial reaction system for degrading wastewater is less than or equal to 7.

[0017] The technical solution of the present invention has achieved the following beneficial technical effects: 1. The activated carbon composite particles prepared by using the preparation method of the activated carbon composite particles of the present invention have achieved good effects in degrading sulfamethoxazole through the combined action of ferric iron and spherical activated carbon particles, and have solved the problems of low degradation efficiency and secondary pollution caused by the direct addition of activated carbon and ferric iron. The materials used in the preparation of the activated carbon composite particles of the present invention are all natural products or biodegradable materials, which will not cause water pollution, and the prepared activated carbon composite particles are easy to recycle.

[0018] 2. When preparing the activated carbon composite particles of the present invention, soluble nitrate is selected as the ferric iron source, and spherical pretreated activated carbon particles with a diameter of 8-10 mm are used as the carrier of ferric iron. By controlling the concentration of ferric iron in the ferric iron solution, the mass-volume ratio of the pretreated activated carbon particles to the ferric iron solution, the oscillation treatment conditions (including oscillation temperature, oscillation rate and oscillation time), and the drying treatment temperature and drying treatment time, the ferric iron in the finally prepared activated carbon composite particles and the pretreated activated carbon particles can effectively play a synergistic activation effect on peroxymonosulfate, thereby improving the degradation efficiency of peroxymonosulfate on sulfamethoxazole in wastewater.

[0019] 3. When the activated carbon composite particles prepared by the present invention are combined with peroxymonosulfate to degrade sulfamethoxazole in wastewater, the activated carbon composite particles adsorb PMS onto its surface or micropores. Under the action of ferric iron loaded on the pretreated activated carbon particles, peroxymonosulfate can generate reactive oxygen species (ROS) such as SO4 •- and •OH - ; after the ferric iron Fe(Ⅲ) completes the activation of peroxymonosulfate, it is transformed into ferrous iron Fe(Ⅱ), and the pretreated activated carbon particles, as an electron mediator, can accelerate the cycle between ferrous iron Fe(Ⅱ) and ferric iron Fe(Ⅲ), avoiding the inactivation of iron species (ensuring the stability of its activation ability for peroxymonosulfate), thereby accelerating the release of reactive oxygen species by peroxymonosulfate, and further improving the degradation efficiency of sulfamethoxazole. At the same time, the surface of the pretreated activated carbon particles combined with ferrous iron Fe(Ⅱ) can activate molecular oxygen to generate a superoxide anion ( 1O2), and this superoxide anion can accelerate the oxidation-reduction reaction of iron, further improving the activation effect of peroxymonosulfate. In addition, the activated carbon composite particles can effectively adsorb peroxymonosulfate and sulfamethoxazole on their surface or micropores in wastewater, which is conducive to increasing the local concentration of peroxymonosulfate and sulfamethoxazole, and then accelerating the activation rate of peroxymonosulfate and the degradation rate of sulfamethoxazole. Description of the Drawings

[0020] Figure 1 Actual photo of the activated carbon composite particles prepared in the embodiment of the present invention; Figure 2 The activated carbon composite particles, activated carbon particles and Fe prepared in the embodiment of the present invention 3+ Efficiency diagram of degrading sulfamethoxazole in water; Figure 3 Efficiency diagram of the activated carbon composite particles prepared in the embodiment of the present invention for degrading sulfamethoxazole at different PMS concentrations; Figure 4 Efficiency diagram of the activated carbon composite particles prepared in the embodiment of the present invention for degrading sulfamethoxazole at different dosages; Figure 5 Efficiency diagram of the activated carbon composite particles prepared in the embodiment of the present invention for degrading sulfamethoxazole at different initial pH values; Figure 6 Efficiency diagram of the activated carbon composite particles prepared in the embodiment of the present invention for degrading sulfamethoxazole in the presence of different inorganic anions; Figure 7 Efficiency diagram of the activated carbon composite particles prepared in the embodiment of the present invention for degrading sulfamethoxazole at different reuse times; Figure 8 Flow chart of preparing the activated carbon composite particles in the embodiment of the present invention. Detailed Description of the Invention

[0021] 1. Preparation of Activated Carbon Composite Particles As Figure 8 shown, the preparation method of the activated carbon composite particles in this embodiment includes the following steps: Step (1), preparing ferric iron solution: Weigh 3 g of ferric nitrate nonahydrate and place it in a conical flask with a volume of 200 mL, and add 100 mL of ultrapure water; then place the conical flask in an ultrasonic oscillator and ultrasonically vibrate it at a frequency of 30 kHz for 5 min at room temperature to obtain ferric iron solution; Step (2), pretreatment of activated carbon particles: Weigh 3 g of activated carbon particles (commercially available Carbonor spherical activated carbon with a diameter of 8 - 10 mm), add them to a 100 mL beaker, and successively add 0.1 mmol / L hydrochloric acid solution, methanol, and ultrapure water to wash the surface dust and waste residues. The soaking time of the activated carbon particles in the hydrochloric acid solution is 24 h; the soaking time in methanol is 1 h; the soaking time in ultrapure water is 1 h; then place the washed activated carbon particles in a dryer at 105 °C for 12 h to obtain pretreated activated carbon particles, named activated carbon, denoted as AC; Step (3), preparation of activated carbon composite particles: Add 1 g of pretreated activated carbon particles to the ferric iron solution prepared in step (1), place the conical flask in a constant temperature shaker, shake it at 25 °C and 180 rpm for 24 h, then take it out, wash it three times with ultrapure water, and place the washed carbon particles in a constant temperature drying oven at 105 °C for 12 h. After drying, activated carbon composite particles (as Figure 1 shown) are obtained, named iron-modified activated carbon, denoted as FAC.

[0022] 2. Method for degrading sulfamethoxazole Take three 100 mL sulfamethoxazole solutions with a mass concentration of 30 mg / L and add them to three 250 mL conical flasks respectively. Weigh 2.4 g of activated carbon composite particles (FAC), 2.4 g of pretreated activated carbon particles (AC), and 1 mL of 100 mmol / L ferric nitrate solution and add them to the above two conical flasks respectively. Then add 1 mL of 100 mmol / L peroxymonosulfate (PMS) solution respectively, mix evenly, and adjust the initial pH to 7. Then place them in a constant temperature shaker with a rotation speed of 180 r / min, control the temperature at 25 °C during the reaction, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Each time, take 100 μL of the sample with a pipette, simultaneously add 100 μL of equal amount of methanol to quench the reaction, then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22 μm filter membrane into an injection vial, and finally measure the sample with an ultraviolet spectrophotometer.

[0023] Figure 2 is the efficiency comparison chart of activated carbon composite particles, activated carbon particles and Fe 3+ for degrading sulfamethoxazole in water. Figure 2 The results show that compared with using only pretreated activated carbon particles or only using Fe 3+The combined use of PMS for sulfamethoxazole degradation shows that the activated carbon composite particles prepared by the method of this example have significantly better degradation effects when combined with PMS for sulfamethoxazole degradation. Moreover, compared with activated carbon particles, the activated carbon composite particles modified with ferric ions have a significantly improved activation effect on PMS, and the removal rate of sulfamethoxazole is increased by about 30%.

[0024] 3. Degradation of sulfamethoxazole by activated carbon composite particles activating PMS with different concentrations Take 100 mL of 6 portions of sulfamethoxazole solution with a mass concentration of 30 mg / L and add them into 6 250-mL conical flasks respectively. Weigh 2.4 g of FAC and add it into the conical flasks, then add PMS, and set its concentration gradient in the system to be 0.5 mmol / L, 0.7 mmol / L, 0.9 mmol / L, 1 mmol / L, 1.1 mmol / L, 1.3 mmol / L. Adjust the initial pH to 7, then place it in a constant-temperature shaker with a rotation speed of 180 r / min. Control the temperature at 25 °C during the reaction process, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Take 100 μL of sample each time with a pipette, add 100 μL of equal-volume methanol to quench the reaction simultaneously, then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22-μm filter membrane into the injection vial, and finally measure the sample with an ultraviolet spectrophotometer.

[0025] Figure 3 It is the efficiency diagram of the activated carbon composite particles for sulfamethoxazole degradation at different PMS concentrations. Figure 3 The results show that as the PMS concentration increases from 0.5 mmol / L to 1 mmol / L, the degradation efficiency of sulfamethoxazole gradually increases and can reach 90%. This is because at low PMS concentrations, the number of sulfate radicals and hydroxyl radicals generated by activation is limited, so a relatively low degradation rate is shown. As the PMS concentration increases, the generated reactive radicals increase, so the degradation rate of sulfamethoxazole increases significantly. However, when the PMS concentration continues to increase to 1.3 mmol / L, the degradation efficiency of sulfamethoxazole gradually decreases. This is mainly due to the reaction between the generated sulfate radicals, resulting in the consumption of sulfate radicals with high oxidation activity.

[0026] 4. Degradation of sulfamethoxazole by activated carbon composite particles at different dosages Take 4 portions of 100 mL sulfamethoxazole solutions with a mass concentration of 30 mg / L and add them into 4 250 mL conical flasks respectively. Then weigh 0.8 g, 1.6 g, 2.4 g, and 3.2 g of FAC and add them into the conical flasks respectively. Then add 1 mL of 100 mmol / L PMS solution, adjust its initial pH to 7, and then place it in a constant temperature shaker with a rotation speed of 180 r / min. During the reaction process, control the temperature at 25 °C, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Each time, sample 100 μL with a pipette, simultaneously add 100 μL of equal amount of methanol to quench the reaction, then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22 μm filter membrane into the injection bottle, and finally use an ultraviolet spectrophotometer to measure the sample.

[0027] Figure 4 It is the efficiency graph of the degradation of sulfamethoxazole by activated carbon composite particles at different dosages. Figure 4 The results show that as the dosage increases from 8 g / L to 24 g / L, the degradation efficiency of sulfamethoxazole gradually increases and can reach 90%. However, when the dosage continues to increase to 32 g / L, the degradation efficiency of sulfamethoxazole decreases, indicating that the dosage of FAC reaches the saturation state at 24 g / L.

[0028] 5. Degradation of sulfamethoxazole by activated carbon composite particles at different initial pH values Take 6 portions of 100 mL sulfamethoxazole solutions with a mass concentration of 30 mg / L and add them into 6 250 mL conical flasks respectively. Weigh 6 portions of 2.4 g of FAC and add them into the conical flasks respectively. Then add 1 mL of 100 mmol / L PMS solution respectively, and adjust the initial pH to 3, 5, 7, 9, 10, and 11 respectively. Then place it in a constant temperature shaker with a rotation speed of 180 r / min. During the reaction process, control the temperature at 25 °C, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Each time, sample 100 μL with a pipette, simultaneously add 100 μL of equal amount of methanol to quench the reaction, then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22 μm filter membrane into the injection bottle, and finally use an ultraviolet spectrophotometer to measure the sample.

[0029] Figure 5 It is the efficiency graph of the degradation of sulfamethoxazole by activated carbon composite particles at different pH values. Figure 5The results showed that when pH = 3 and pH = 5, there was no obvious impact on the degradation of sulfamethoxazole compared to pH = 7, and there was only a slight increase. However, as the pH increased from 7 to 11, the degradation efficiency of sulfamethoxazole gradually decreased to 60%. This indicates that acidic and neutral conditions are suitable for the degradation of sulfamethoxazole, while alkaline conditions will inhibit its degradation.

[0030] 6. Degradation of sulfamethoxazole by activated carbon composite particles under different inorganic anions Take 5 portions of 100 mL sulfamethoxazole solutions with a mass concentration of 30 mg / L and add them to 5 250 mL conical flasks respectively. Weigh 5 portions of 2.4 g of FAC and add them to the conical flasks respectively, and then add 1 mL of 100 mmol / L PMS solution respectively. Then add 10 mmol / L of Cl - , CO3 2- , NO3 - , SO4 2- , and a control group; adjust the initial pH to 7, then place it in a constant temperature shaker with a rotation speed of 180 r / min. During the reaction, control the temperature at 25 °C, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Each time, sample 100 μL with a pipette, and at the same time add 100 μL of equal volume of methanol to quench the reaction. Then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22 μm filter membrane into the injection bottle, and finally measure the sample using an ultraviolet spectrophotometer.

[0031] Figure 6 It is the efficacy diagram of the degradation of sulfamethoxazole by activated carbon composite particles under different inorganic anions. Figure 6 The results showed that when Cl - , NO3 - , SO4 2- were present in the system, the degradation rate of sulfamethoxazole could reach over 70%. Therefore, the FAC composite catalyst can adapt to complex water quality changes and overcome the shortcoming of traditional catalysts that the catalytic efficiency decreases due to the influence of water quality.

[0032] 7. Degradation of sulfamethoxazole by activated carbon composite particles with different recovery times Take 100 mL of sulfamethoxazole solution with a mass concentration of 30 mg / L and add it to a 250 mL conical flask. Weigh 2.4 g of FAC and add it to the conical flask respectively, and then add 1 mL of 100 mmol / L PMS solution. Adjust the initial pH to 7, then place it in a constant temperature shaker with a rotation speed of 180 r / min. Control the temperature at 25 °C during the reaction, and the sampling time intervals are: 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min. Each time, sample 100 μL with a pipette, and at the same time add 100 μL of equal amount of methanol to quench the reaction. Then add 800 μL of methanol aqueous solution with a volume concentration of 50% to dilute the sample solution, filter it through a 0.22 μm filter membrane into the injection vial, and finally use an ultraviolet spectrophotometer to measure the sample. After washing the activated carbon composite particles repeatedly with ultrapure water and methanol, place them in an oven at 105 °C to dry. After taking them out, repeat the above reaction. The reaction process is repeated 5 times.

[0033] Figure 7 It is the efficacy diagram of the degradation of sulfamethoxazole by the activated carbon composite particles at different repetition times. Figure 7 The results show that in the second and third reactions of the recycled activated carbon composite particles, the degradation of sulfamethoxazole decreased by less than 5%. The degradation rates of sulfamethoxazole in the fourth and fifth reactions only decreased by 7% and 10% respectively. It shows that the activated carbon composite particles prepared by the present invention have good recyclability and are an economical, efficient and green environmental engineering material.

[0034] Obviously, the above embodiments are only examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the claims of this patent application.

Claims

1. A preparation method of activated carbon composite particles, characterized in that It includes the following steps: Step (1), preparing a ferric iron solution: Dissolve a soluble ferric iron salt in ultrapure water and perform ultrasonic oscillation to obtain a ferric iron solution; Step (2), pretreatment of activated carbon particles: Soak and clean the activated carbon particles successively with a hydrochloric acid solution, methanol, and ultrapure water. After the cleaning is completed, perform a drying treatment. After the drying treatment is completed, obtain pretreated activated carbon particles; Step (3), preparing activated carbon composite particles: Add the pretreated activated carbon particles to the ferric iron solution for oscillation treatment; After the oscillation treatment, take them out and wash with ultrapure water. After the washing, perform a drying treatment. After the drying treatment is completed, obtain activated carbon composite particles.

2. The preparation method of the activated carbon composite particles according to claim 1, characterized in that, In step (1), the soluble ferric iron salt is one or a mixture of two or more of ferric nitrate, ferric nitrate hydrate, ferric chloride, ferric chloride hydrate, ferric sulfate, or ferric sulfate hydrate.

3. The preparation method of the activated carbon composite particles according to claim 1, characterized in that, In step (1), the conditions of ultrasonic oscillation are: ultrasonic oscillation at a frequency of 20 - 40 kHz for 5 - 10 min at room temperature; the molar concentration of ferric iron in the ferric iron solution is 0.07 - 0.09 mol / L.

4. The preparation method of the activated carbon composite particles according to claim 1, wherein, In step (2), the molar concentration of the hydrochloric acid solution is 0.1 - 0.2 mmol / L; the soaking time of the hydrochloric acid solution on the activated carbon particles is 18 - 24 h; the soaking time of methanol on the activated carbon particles is 0.5 - 1.5 h; the soaking time of ultrapure water on the activated carbon particles is 0.5 - 1.5 h.

5. The preparation method of the activated carbon composite particles according to claim 1, characterized in that, In step (2), the diameter of the activated carbon particles is 8 - 10 mm; the drying treatment conditions are: 100 - 110 °C, 10 - 15 h.

6. The preparation method of the activated carbon composite particles according to claim 1, characterized in that In step (1), the molar concentration of ferric iron in the ferric iron solution is 0.07 - 0.09 mol / L; in step (3), the mass - to - volume ratio of the pretreated activated carbon particles to the ferric iron solution is 1 g:(80 - 100) mL.

7. The preparation method of the activated carbon composite particles according to claim 1, wherein, In step (3), the oscillation treatment conditions are: 20 - 30 °C, 150 - 200 rpm, 18 - 24 h; the drying treatment conditions are: 100 - 110 °C, 10 - 15 h.

8. The preparation method of the activated carbon composite particles according to claim 1, characterized in that, In step (1), the soluble ferric iron salt is ferric nitrate nonahydrate, and the ultrasonic oscillation conditions are: ultrasonic oscillation at a frequency of 30 kHz for 5 min at room temperature; the molar concentration of ferric iron in the ferric iron solution is 0.074 mol / L; In step (2), the diameter of the activated carbon particles is 8 - 10 mm; the molar concentration of the hydrochloric acid solution is 0.1 mmol / L; the soaking time of the hydrochloric acid solution on the activated carbon particles is 24 h; the soaking time of methanol on the activated carbon particles is 1 h; the soaking time of ultrapure water on the activated carbon particles is 1 h; the drying treatment conditions are: 105 °C, 12 h; In step (3), the mass - to - volume ratio of the pretreated activated carbon particles to the ferric iron solution is 1 g:100 mL; the oscillation treatment conditions are: 25 °C, 180 rpm, 24 h; the drying treatment conditions are: 105 °C, 12 h.

9. A method for degrading sulfamethoxazole in wastewater, characterized in that, Add peroxymonosulfate and the activated carbon composite particles prepared by the preparation method of the activated carbon composite particles as described in any one of claims 1 - 8 to the wastewater containing sulfamethoxazole to degrade sulfamethoxazole in the wastewater.

10. The method for degrading sulfamethoxazole in wastewater according to claim 9, wherein In the initial reaction system for degrading wastewater: the mass ratio of sulfamethoxazole to the activated carbon composite particles is 1:(700 - 900), and the molar ratio of sulfamethoxazole to peroxymonosulfate is 1:(7 - 10); the pH of the initial reaction system for degrading wastewater is less than or equal to 7.

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