Catalyst for degrading ciprofloxacin by photo-synergistically activating PMS as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for degrading ciprofloxacin by activating PMS through light synergism as well as a preparation method and application of the catalyst, and solves the technical problems that in the prior art, when a powdery transition metal catalyst is used in an aqueous solution, the PMS activation efficiency is low, agglomeration and inactivation are easy to occur, and recycling is difficult. The preparation method comprises the following steps: (1) dispersing soluble ferric salt, soluble cobalt salt and trimesic acid in water to obtain a reaction solution; (2) carrying out hydrothermal treatment on the reaction liquid to generate a solid-liquid mixture; (3) collecting, washing and drying solids in the solid-liquid mixture to obtain an iron-cobalt composite material; (4) preparing a suspension containing the iron-cobalt composite material and chitosan; (5) adsorbing the suspension liquid by using melamine sponge to obtain a green body; and (6) carrying out heat treatment on the green body to obtain the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of degrading ciprofloxacin, and in particular, to a catalyst for photocatalytically synergistic activating PMS to degrade ciprofloxacin, a preparation method thereof, and an application thereof. Background Art

[0002] As a third-generation fluoroquinolone antibiotic, ciprofloxacin (CIP) cannot be effectively biodegradated due to its high chemical stability and ultimately endangers human health through the enrichment of the food chain. Therefore, there is an urgent need for an economical and effective technology to treat such organic pollutants in the water environment. Currently, the relatively effective methods for removing antibiotics in water mainly include membrane filtration, adsorption, and advanced oxidation processes. Among them, advanced oxidation technology (AOPS), as one of the treatment processes for efficiently treating refractory organic compounds, has attracted much attention due to its high reaction activity and oxidative degradation ability.

[0003] In advanced oxidation technology, the advanced oxidation process based on sulfate radical (SO4 ·- ) has experienced rapid development in recent years, which is attributed to the fact that sulfate radical has a higher redox potential, a wider pH adaptation range, a longer half-life, and stronger selective oxidation ability compared with hydroxyl radical (·OH). Activating PMS (peroxymonosulfate) to generate sulfate radical is currently the most widely used advanced oxidation method. The existing PMS activation methods mainly include heat, alkali, ultraviolet light, carbonaceous materials, transition metal catalysts, etc. Among them, activating PMS with transition metal catalysts under ultraviolet light synergy is one of the most effective methods currently. However, the existing powdered transition metal catalysts face problems such as low PMS activation efficiency, easy agglomeration and deactivation, and difficulty in recycling when used in aqueous solutions. Summary of the Invention

[0004] In order to solve the technical problems of low PMS activation efficiency, easy agglomeration and deactivation, and difficulty in recycling existing powdered transition metal catalysts when used in aqueous solutions, the present invention provides a catalyst for photocatalytically synergistic activating PMS to degrade ciprofloxacin, a preparation method thereof, and an application thereof. The technical solutions are as follows:

[0005] A preparation method of a catalyst for photocatalytically synergistic activating PMS to degrade ciprofloxacin, comprising the following steps:

[0006] (1) Disperse soluble iron salt, soluble cobalt salt, and trimesic acid in water to obtain a reaction solution;

[0007] (2) Perform hydrothermal treatment on the reaction solution to generate a solid-liquid mixture;

[0008] (3) Collect, wash, and dry the solid in the solid-liquid mixture to obtain an iron-cobalt composite material;

[0009] (4) Prepare a suspension containing the iron-cobalt composite material and chitosan;

[0010] (5) Adsorb the suspension with a melamine sponge to obtain a green body;

[0011] (6) Perform heat treatment on the green body to obtain the catalyst.

[0012] As a further improvement of the above preparation method: Step (1) is specifically:

[0013] Prepare a first solution, in which the molar ratio of Fe 3+ to Co 4+ is 100:(1-10), and the concentration of Fe 3+ is 0.4-0.8 mol / L;

[0014] Prepare a second solution, in which the concentration of trimesic acid in the second solution is 0.11-0.18 mol / L;

[0015] Mix the first solution and the second solution according to a volume ratio of 1:2, and then stir for 0.5-1 hour to obtain the reaction solution.

[0016] As a further improvement of the above preparation method: In step (2), the hydrothermal reaction temperature is 130-170 °C, and the hydrothermal reaction duration is 20-30 hours.

[0017] As a further improvement of the above preparation method: In step (4), the binder is chitosan; prepare the suspension according to the ratio of adding 2-10 g of the iron-cobalt composite material and 0.5 mL of 0.5-1.5 wt% chitosan ethanol solution per 1 mL of water.

[0018] As a further improvement of the above preparation method: In step (5), inject 0.5-1 mL of the suspension into each 1 cm 3 of the melamine sponge.

[0019] As a further improvement of the above preparation method: In step (6), the heat treatment temperature is 80-100 °C, and the heat treatment duration is 2-4 hours.

[0020] The catalyst for photocatalytic synergistic activation of PMS to degrade ciprofloxacin is prepared by the above preparation method.

[0021] The reactor for photocatalytic synergistic activation of PMS to degrade ciprofloxacin includes an inner tube and an outer tube nestedly arranged. An ultraviolet lamp is installed in the inner tube. An inlet and an outlet are opened on the outer tube. A light-shielding layer is sleeved outside the outer tube. The gap between the inner tube and the outer tube is filled with the catalyst; the inlet is connected to the liquid to be treated containing PMS and ciprofloxacin; the catalyst is prepared by the above preparation method.

[0022] A purification method for ciprofloxacin in water bodies, wherein the catalyst prepared by the above preparation method is used to activate PMS under light to degrade ciprofloxacin in water bodies.

[0023] First, the present invention successfully prepares an iron-cobalt composite material capable of efficiently activating PMS by a simple process. This iron-cobalt composite material can utilize the synergistic effect of iron and cobalt elements to accelerate the redox cycle between metal valence states and enhance the catalytic activity of the material, effectively solving the technical problem of the low activation efficiency of existing transition metal catalysts for PMS. Secondly, the present invention uses melamine sponge as a carrier and successfully immobilizes the iron-cobalt composite material on the melamine sponge by a simple process, which can not only effectively avoid the inactivation caused by the aggregation of metal catalysts, but also facilitate the convenient and efficient recycling of the catalyst. In addition, in order to better achieve the successful and stable anchoring of the iron-cobalt composite material on the melamine sponge, the present invention uses a chitosan polymer with rich amino groups as a bridge connecting the carrier and the metal catalyst. The rich amino groups can produce mucosal adhesiveness, making the iron-cobalt composite material not easy to fall off.

[0024] The following further describes the present invention in conjunction with the drawings and specific embodiments. The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0025] The drawings constituting a part of the present invention are used to assist in the understanding of the present invention. The content provided in the drawings and the related descriptions in the present invention can be used to explain the present invention, but do not constitute an improper limitation to the present invention. In the drawings:

[0026] Figure 1 It is the degradation effect diagram of iron-cobalt composite materials with different cobalt contents on CIP (ciprofloxacin).

[0027] Figure 2 It is the degradation kinetics diagram of iron-cobalt composite materials with different cobalt contents on CIP.

[0028] Figure 3 It is the degradation effect diagram of Fe / Co-5% with different dosages on CIP.

[0029] Figure 4 It is the degradation kinetics diagram of Fe / Co-5% with different dosages on CIP.

[0030] Figure 5 It is the degradation effect diagram of Fe / Co-5% on CIP under different PMS dosages.

[0031] Figure 6Degradation kinetics diagrams of CIP by Fe / Co-5% at different PMS dosages.

[0032] Figure 7 Degradation effect diagrams of CIP by Fe / Co-5% at different pH values.

[0033] Figure 8 Degradation kinetics diagrams of CIP by Fe / Co-5% at different pH values.

[0034] Figure 9 Reusability result diagrams of Fe / Co-5%.

[0035] Figure 10 SEM photos of Fe100% (a-c) and Fe / Co-5% (d-f).

[0036] Figure 11 UV-Vis diffuse reflectance spectra of Fe100% and Fe / Co-5%.

[0037] Figure 12 Steady-state photoluminescence spectra of Fe100% and Fe / Co-5%.

[0038] Figure 13 Degradation effect diagrams of CIP by the catalyst at different Fe / Co-5% loadings.

[0039] Figure 14 Degradation kinetics diagrams of CIP by the catalyst at different Fe / Co-5% loadings.

[0040] Figure 15 Degradation effect diagrams of CIP under different reaction conditions.

[0041] Figure 16 Degradation kinetics diagrams of CIP under different reaction conditions.

[0042] Figure 17 Reusability result diagrams of Fe / Co / CMS-5%-2.

[0043] Figure 18 Degradation effect diagrams of Fe / Co / CMS-5%-2 on aquaculture wastewater.

[0044] Figure 19 SEM photos of MS (a-c), CMS (d-f), and Fe / Co / CMS-5%-2 (g-i).

[0045] Figure 20 UV-Vis diffuse reflectance spectra of MS, CMS, and Fe / Co / CMS-5%-2.

[0046] Figure 21Steady-state photoluminescence spectra of MS, CMS, and Fe / Co / CMS-5%-2.

[0047] Figure 22 Structural schematic diagram of an embodiment of the reactor for photocatalytic activation of PMS to degrade ciprofloxacin according to the present invention.

[0048] Figure 22 The relevant markings in [Figure] are: 100 - outer tube, 110 - water inlet, 120 - water outlet, 200 - inner tube, 300 - ultraviolet lamp, 400 - catalyst or iron-cobalt composite material, 500 - sealing plug. Detailed implementation manners

[0049] The present invention will be described clearly and completely below with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that:

[0050] The technical solutions and technical features provided in each part including the following description of the present invention can be combined with each other without conflict.

[0051] In addition, the embodiments of the present invention involved in the following description are usually only a part of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Regarding the terms and units in the present invention. The terms "including", "having" and any variations thereof in the specification, claims and relevant parts of the present invention are intended to cover non-exclusive inclusion.

[0053] Example A1

[0054] The preparation method of the catalyst for photocatalytic activation of PMS to degrade ciprofloxacin in this example includes the following steps:

[0055] (1) Disperse FeCl3·6H2O, Co(NO3)2·6H2O, and trimesic acid in water to obtain a reaction solution; specifically:

[0056] Prepare a first solution, in which the molar ratio of Fe 3+ to Co 4+ is 100:1, and the concentration of Fe 3+ is 0.6 mol / L;

[0057] Prepare a second solution, in which the concentration of trimesic acid is 0.164 mol / L;

[0058] Mix the first solution and the second solution according to a volume ratio of 1:2, and then stir for 0.5 hours to obtain a reaction solution.

[0059] (2) Perform hydrothermal treatment on the reaction solution. The hydrothermal reaction temperature is 150 °C, and the hydrothermal reaction duration is 24 hours to generate a solid-liquid mixture.

[0060] (3) Collect, wash, and dry the solid in the solid-liquid mixture to obtain an iron-cobalt composite material named Fe / Co-1%.

[0061] (4) Prepare a suspension containing the iron-cobalt composite material and chitosan according to the ratio of adding 2 g of the iron-cobalt composite material and 0.5 mL of 1 wt% chitosan ethanol solution to every 1 mL of water.

[0062] (5) Immerse the melamine sponge (MS) in acetone and sonicate for 10 min, then repeatedly wash it ultrasonically with ultrapure water and absolute ethanol more than 2 times, dry it at 80 °C for 3 h, and then cut it into a 1×1×2 cm cuboid; inject 1.5 mL of the suspension into each melamine sponge block to obtain a green body.

[0063] (6) Perform heat treatment on the green body. The heat treatment temperature is 90 °C, and the heat treatment duration is 3 hours to obtain a catalyst named Fe / Co / CMS-1%-2.

[0064] Example A2

[0065] Compared with Example A1, the difference in the preparation method of the catalyst for photocatalytically synergistically activating PMS to degrade ciprofloxacin in this example is that the molar ratio of Fe 3+ to Co 4+ in the first solution is 100:3, and the obtained iron-cobalt composite material is named Fe / Co-3%.

[0066] Example A3

[0067] Compared with Example A1, the difference in the preparation method of the catalyst for photocatalytically synergistically activating PMS to degrade ciprofloxacin in this example is that the molar ratio of Fe 3+ to Co 4+ in the first solution is 100:5, and the obtained iron-cobalt composite material is named Fe / Co-5%.

[0068] Example A4

[0069] Compared with Example A1, the difference in the preparation method of the catalyst for photocatalytically synergistically activating PMS to degrade ciprofloxacin in this example is that the molar ratio of Fe 3+ to Co 4+ in the first solution is 100:10, and the obtained iron-cobalt composite material is named Fe / Co-10%.

[0070] Control Example A1

[0071] Compared with Example A1, the difference in the preparation method of the catalyst for photocatalytically synergistic activating PMS to degrade ciprofloxacin in this control example is that: Co is not contained in the first solution 4+ , and the obtained iron-cobalt composite material is named Fe100%.

[0072] Control Example A2

[0073] Compared with Example A1, the difference in the preparation method of the catalyst for photocatalytically synergistic activating PMS to degrade ciprofloxacin in this control example is that: the molar ratio of Fe 3+ to Co 4+ in the first solution is 100:25, and the obtained iron-cobalt composite material is named Fe / Co-25%.

[0074] Figure 1 are the degradation effect diagrams of iron-cobalt composite materials with different cobalt contents on CIP (ciprofloxacin). Figure 2 are the degradation kinetic diagrams of iron-cobalt composite materials with different cobalt contents on CIP. As Figure 1 shown, when the CIP concentration is 10 mg / L, the dosage of the iron-cobalt composite material is 50 mg / L, the PMS concentration is 0.15 g / L, and the pH is 4.2, during the degradation process of the photocatalytically synergistic activating PMS system, Fe / Co-5% of Example A3 shows a more excellent CIP degradation efficiency of 87.8%, with a 12.5% improvement in the catalytic degradation effect compared to Fe100% of Control Example A1. As Figure 2 shown, the pseudo-first-order reaction rate constants of the cobalt-containing iron-cobalt composite materials all exceed that of Fe100% (0.0209 min -1 ), among which, the degradation rate of Fe / Co-5% is the highest at 0.0352 min -1 . It can be seen that the iron-cobalt composite material shows more excellent catalytic activity, which benefits from the redox cycle between the iron and cobalt active sites in the material under photocatalytically synergistic conditions, promoting the synergistic activation of PMS.

[0075] Figure 3 are the degradation effect diagrams of different dosages of Fe / Co-5% on CIP. Figure 4 are the degradation kinetic diagrams of different dosages of Fe / Co-5% on CIP. As Figure 3 ​As shown, when the CIP concentration is 10 mg / L, the PMS concentration is 0.15 g / L, and the pH is 4.2, as the dosage of Fe / Co-5% increases from 5 mg / L to 50 mg / L, the CIP degradation efficiency increases from 63.5% to 88.2%. This is attributed to the increase in the reactive sites of the catalyst participating in the reaction and the enhancement of the photocatalytic effect. However, when the catalyst dosage is further increased, the degradation effect does not improve significantly. This may be because the higher concentration of the catalyst increases the turbidity of the solution, thereby reducing the light irradiation intensity required for the reaction. As Figure 4 shown, the pseudo-first-order reaction rate constant of CIP degradation reaches the highest value of 0.0326 min -1 .

[0076] Figure 5 Figure shows the degradation effect of Fe / Co-5% on CIP at different PMS dosages. Figure 6 Figure shows the degradation kinetics of Fe / Co-5% on CIP at different PMS dosages. As Figure 5 shown, when the CIP concentration is 10 mg / L, the dosage of Fe / Co-5% is 50 mg / L, and the pH is 4.2, the CIP degradation efficiency increases with the increase of PMS concentration and finally reaches stability. When the PMS dosage increases from 0.05 g / L to 0.15 g / L, the CIP degradation efficiency also increases from 78.2% to 87.5%, indicating that an appropriate amount of PMS can be efficiently activated by the catalyst, which is beneficial to the generation of active substances and the inhibition of carrier recombination. However, further increasing the PMS dosage has little effect on the improvement of the CIP degradation efficiency. This may be limited by the active sites of the catalyst and the free radical self-quenching reaction. As Figure 6 shown, the change rule of the pseudo-first-order degradation rate constant at different PMS dosages is consistent with the change rule of the above CIP degradation effect.

[0077] Figure 7 Figure shows the degradation effect of Fe / Co-5% on CIP at different pH values. Figure 8 Figure shows the degradation kinetics of Fe / Co-5% on CIP at different pH values. As Figure 7 shown, when the CIP concentration is 10 mg / L, the dosage of Fe / Co-5% is 50 mg / L, and the PMS concentration is 0.15 g / L, the degradation effects at pH values of 4.2 (original), 3, 5, 7, 9, and 11 are 87.9%, 85.0%, 86.8%, 85.9%, 85.9%, and 87.4% respectively, indicating that the Fe / Co-5% + PMS system can effectively degrade CIP in the range of the initial solution pH = 3 - 11. As Figure 8As shown, the value of the pseudo-first-order reaction rate constant gradually decreases with the increase of pH in the range of pH = 3 - 9, but suddenly increases to the maximum value of 0.0356 min at pH = 11 -1 , which may be related to the base activation of PMS.

[0078] Figure 9 Figure shows the reuse results of Fe / Co-5%. Five reuse experiments were carried out under optimized reaction conditions to evaluate the reusability of Fe / Co-5%. As Figure 9 shown, the catalytic activity of Fe / Co-5% has high stability during five reuse cycles, and the degradation efficiency of CIP still remains at 77.8% in the fifth degradation experiment. It can be seen that the good catalytic activity and reusability of Fe / Co-5% further prove its application potential in the photo-synergistic activation of PMS for CIP degradation.

[0079] Figure 10 Figure shows the SEM images of Fe100% (a - c) and Fe / Co-5% (d - f). As Figure 10 shown, both Fe100% and Fe / Co-5% have nanoparticle sizes and present irregular morphologies. The average diameter of Fe100% is 300 - 500 nm, and the average diameter of Fe / Co-5% is 500 - 1000 nm.

[0080] The contents of C element, O element, Fe element and Co element in Fe / Co-5% are obtained by energy spectrum analysis as 65.49%, 25.26%, 8.61% and 0.64% respectively.

[0081] Figure 11 Figure shows the UV-Vis diffuse reflectance spectra of Fe100% and Fe / Co-5%. As Figure 11 shown, both Fe100% and Fe / Co-5% show light responses in the range of 200 - 700 nm.

[0082] Figure 12 Figure shows the steady-state photoluminescence spectra of Fe100% and Fe / Co-5%. As Figure 12 shown, at the excitation wavelength of 370 nm, the peak intensity of Fe / Co-5% is weaker than that of Fe100%, indicating that the separation efficiency of photo-generated electrons and holes in Fe / Co-5% is more excellent.

[0083] Example B1

[0084] Compared with Example A3, the difference in the preparation method of the catalyst for photocatalytic synergistic activation of PMS to degrade ciprofloxacin in this example is as follows: A suspension was prepared according to the ratio of adding 4 g of iron-cobalt composite material and 0.5 mL of 1 wt% chitosan ethanol solution to every 1 mL of water, and the catalyst was named Fe / Co / CMS-5%-4.

[0085] Example B2

[0086] Compared with Example A3, the difference in the preparation method of the catalyst for photocatalytic synergistic activation of PMS to degrade ciprofloxacin in this example is as follows: A suspension was prepared according to the ratio of adding 10 g of iron-cobalt composite material and 0.5 mL of 1 wt% chitosan ethanol solution to every 1 mL of water, and the catalyst was named Fe / Co / CMS-5%-10.

[0087] Control Example B1

[0088] Compared with Example A3, the difference in the preparation method of the catalyst for photocatalytic synergistic activation of PMS to degrade ciprofloxacin in this example is as follows: The suspension did not contain iron-cobalt composite material, and the catalyst was named CMS.

[0089] Control Example B2

[0090] Compared with Example A3, the difference in the preparation method of the catalyst for photocatalytic synergistic activation of PMS to degrade ciprofloxacin in this example is as follows: A suspension was prepared according to the ratio of adding 1 g of iron-cobalt composite material and 0.5 mL of 1 wt% chitosan ethanol solution to every 1 mL of water, and the catalyst was named Fe / Co / CMS-5%-1.

[0091] Figure 13 It is the degradation effect diagram of CIP by the catalyst under different Fe / Co-5% loadings. Figure 14 It is the degradation kinetic diagram of CIP by the catalyst under different Fe / Co-5% loadings. As Figure 13 shown, under the optimized reaction conditions, the degradation efficiency of the catalyst for CIP increases with the increase of the Fe / Co-5% loading, and there is no significant change in the degradation effect after the 2 mg loading. Among them, the CIP degradation efficiency of Fe / Co / CMS-5%-2 is 86.7%, which is 26.6% higher than that of CMS. As Figure 14 shown, the pseudo-first-order reaction rate constants of all catalysts exceed that of CMS (0.0094 min -1 ).

[0092] Figure 15 It is the degradation effect diagram of CIP under different reaction conditions. Figure 16 It is the degradation kinetic diagram of CIP under different reaction conditions. As Figure 15As shown, only 12.1% of CIP was degraded in the presence of only PMS. In the Fe / Co / CMS-5%-2 + PMS system, the degradation efficiency of CIP was significantly increased to 35.5%, indicating that Fe / Co / CMS-5%-2 has a heterogeneous activation effect on the presence of PMS. In the Fe / Co / CMS-5%-2 + Photo (ultraviolet light irradiation) system, the degradation efficiency of CIP was 30.4%, indicating that Fe / Co / CMS-5%-2 can be used as a photocatalyst, which can generate electron-hole pairs under light irradiation to promote the degradation of CIP. In the Photo + PMS system, the degradation efficiency of CIP reached 62.7%, indicating that ultraviolet light can also effectively activate PMS to generate the active substances required for the reaction. The degradation efficiency of CIP in the Fe / Co / CMS-5%-2 + PMS + Photo system reached as high as 86.6%. It can be seen that there is a synergistic effect between light irradiation and Fe / Co / CMS-5%-2 in activating PMS to degrade CIP. As Figure 16 shown, the pseudo-first-order degradation rate constant of the Fe / Co / CMS-5%-2 + PMS + Photo system was 0.0202 min -1 , which was 2.1 times that of the Photo + PMS system, 5.5 times that of the Fe / Co / CMS-5%-2 + PMS system, and 6.1 times that of the Fe / Co / CMS-5%-2 + Photo system.

[0093] Figure 17 Figure for the reuse results of Fe / Co / CMS-5%-2. As Figure 17 shown, Fe / Co / CMS-5%-2 maintained a high catalytic activity during the five reuse cycles, and the degradation efficiency of CIP was still 80.6% in the fifth degradation experiment, showing excellent reusability and broad application prospects in the photocatalytic synergistic activation of PMS to degrade CIP.

[0094] Figure 18 Figure for the degradation effect of Fe / Co / CMS-5%-2 on aquaculture wastewater. As Figure 18 shown, under the optimized reaction conditions, the degradation efficiency of CIP in aquaculture wastewater by Fe / Co / CMS-5%-2 decreased but still remained at about 83%, and there was no obvious change in its degradation efficiency with the extension of the reaction time. Aquaculture wastewater is one of the water bodies with relatively common quinolone antibiotic pollution. It can be seen that the catalyst of the present invention has great potential for the actual purification and application of this actual water body.

[0095] Figure 19 SEM photographs of MS (a-c), CMS (d-f) and Fe / Co / CMS-5%-2 (g-i). From Figure 19It can be seen that the original MS exhibits a smooth surface and a porous 3D network structure, which can provide abundant voids for the subsequent loading of iron-cobalt composite materials. The image of the CMS material indicates that chitosan can form a viscous film between the pores of MS, which will contribute to the loading of the catalyst. There are many nanoparticles on the surface of the viscous film formed by chitosan in Fe / Co / CMS-5%-2, which confirms the successful anchoring of Fe / Co-5% on the MS support. At the same time, it can be found that Fe / Co-5%, which is relatively easy to agglomerate itself, is dispersed and anchored in the viscous film formed by chitosan through loading, inhibiting the agglomeration of the nanomaterials and exposing more active sites to enhance its catalytic activity.

[0096] Figure 20 are the UV-visible diffuse reflectance spectra of MS, CMS and Fe / Co / CMS-5%-2. As can be seen from Figure 20 it, MS has a narrow absorption band less than 350 nm, and the light response range of CMS is broadened due to the loading of the conductive polymer material chitosan. Relatively speaking, Fe / Co / CMS-5%-2 has a broad absorption band of 200-600 nm, which can be attributed to the successful loading of Fe / Co-5% in the catalyst.

[0097] Figure 21 are the steady-state photoluminescence spectra of MS, CMS and Fe / Co / CMS-5%-2. As can be seen from Figure 21 it, at the excitation wavelength of 370 nm, the PL peak of Fe / Co / CMS-5%-2 is weaker than that of MS and CMS, indicating that with the loading of Fe / Co-5%, the separation efficiency of photogenerated electrons and holes in the catalyst will be more prominent.

[0098] The above degradation test was carried out using the following reactor.

[0099] Figure 22 is a schematic structural diagram of an embodiment of the reactor for photocatalytically synergistically activating PMS to degrade ciprofloxacin according to the present invention. As shown in Figure 22As shown in the figure, the reactor includes an inner tube 200 and an outer tube 100 which are nested. An ultraviolet lamp 300 (model: GPH287T5L / 4P 12W, LightSources, USA) is installed in the inner tube 200. The inner tube 200 and the ultraviolet lamp 300 are fixed on a sealing plug 500 and are hermetically connected to the outer tube 100 through the sealing plug 500. An inlet 110 and an outlet 120 are provided on the outer tube 100. A light-shielding layer is sleeved outside the outer tube 100. A catalyst or iron-cobalt composite material 400 is filled in the gap between the inner tube 200 and the outer tube 100. The inlet 110 is connected to the liquid to be treated containing PMS (with or without) and CIP. The liquid to be treated is continuously pumped from the inlet 110 into the gap between the inner tube 200 and the outer tube 100 through a peristaltic pump driver (model: BT100-3J, Longer Precision Pump Co., Ltd.).

[0100] During specific tests, a CIP solution is first introduced under dark stirring conditions to enable the catalyst or iron-cobalt composite material 400 to reach an adsorption-desorption equilibrium. Then, an appropriate amount of PMS is added and the light source is turned on for the next reaction. In all experiments, at preset time intervals, 1 mL of the reaction solution is drawn from the outlet 120 with a syringe equipped with a 0.22 μm polyethersulfone syringe filter, and ultraviolet-visible spectral analysis is performed at 277 nm using a USB 4000 ultraviolet-visible spectrophotometer to determine the CIP concentration.

[0101] In the figure, "C0" is the initial concentration of the CIP solution, "C" is the detected concentration of the reaction solution drawn by the syringe, and the degradation efficiency = [1 - (C / C0)] * 100%. The degradation rate constant is calculated through a pseudo-first-order kinetic model.

[0102] An embodiment of the method for purifying ciprofloxacin in water of the present invention is to use the catalyst prepared by the above preparation method to activate PMS under light coaction to degrade ciprofloxacin in water. The water mentioned can be but is not limited to river water, lake water, and aquaculture wastewater.

[0103] SEM photos and EDS spectra were taken using a JSM 7800F field emission scanning electron microscope of JEOL Ltd., Japan. The ultraviolet-visible diffuse reflectance spectra were recorded by a UH-4150 ultraviolet-visible near-infrared spectrophotometer of Hitachi Ltd., Japan. The steady-state photoluminescence spectra were recorded by an FLS1000 steady-state / transient fluorescence spectrometer of Edinburgh Instruments Ltd., UK.

[0104] The above describes the relevant content of the present invention. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Based on the above content of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for photosynthetic activation of PMS for degradation of ciprofloxacin, characterized in that: The following steps are involved: (1) dispersing a soluble iron salt, a soluble cobalt salt, and trimesic acid in water to obtain a reaction solution; (2) subjecting the reaction solution to hydrothermal treatment to generate a solid-liquid mixture; (3) collecting, washing and drying the solid in the solid-liquid mixture to obtain an iron-cobalt composite material; (4) preparing a suspension containing an iron-cobalt composite material and chitosan; (5) using a melamine sponge to absorb the suspension to obtain a green body; (6) The green body is heat treated to obtain a catalyst.

2. The preparation method according to claim 1, characterized in that: Step (1) is specifically as follows: Prepare the first solution, Fe 3+ With Co 4+ The molar ratio of Fe is 100:(1~10), 3+ The concentration is 0.4-0.8 mol / L; preparing a second solution, wherein the concentration of trimesic acid in the second solution is 0.11-0.18 mol / L; The first solution and the second solution are mixed in a volume ratio of 1:2, and then stirred for 0.5 to 1 hour to obtain a reaction solution.

3. The preparation method according to claim 1, characterized in that: In step (2), the hydrothermal reaction temperature is 130 to 170° C., and the hydrothermal reaction time is 20 to 30 hours.

4. The preparation method according to claim 1, characterized in that: In step (4), a suspension is prepared by adding 2 to 10 g of the iron-cobalt composite material and 0.5 mL of 0.5 to 1.5 wt % chitosan ethanol solution to every 1 mL of water.

5. The preparation method according to claim 1, characterized in that: In step (5), every 1 cm 3 Inject 0.5-1 mL of the suspension into the melamine sponge.

6. The preparation method according to claim 1, characterized in that: In step (6), the heat treatment temperature is 80 to 100° C., and the heat treatment time is 2 to 4 hours.

7. A catalyst for photosynthetically activated PMS for degradation of ciprofloxacin, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 6.

8. A reactor for degradation of ciprofloxacin by light-synergistic activation of PMS, characterized in that: It comprises an inner tube and an outer tube which are nested, an ultraviolet lamp is installed in the inner tube, a water inlet and a water outlet are opened on the outer tube, a light shielding layer is sheathed on the outer side of the outer tube, and a catalyst is filled in the gap between the inner tube and the outer tube; The water inlet is connected to the liquid to be treated containing PMS and ciprofloxacin; The catalyst is prepared by the preparation method according to any one of claims 1 to 6.

9. A method for purifying ciprofloxacin in water, characterized in that: The catalyst prepared by the preparation method according to any one of claims 1 to 6 activates PMS under light synergy to degrade ciprofloxacin in water.

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