A cobalt-zirconium bimetallic composite catalyst, its preparation method and application
By preparing a cobalt-zirconium bimetallic composite catalyst, the problems of short free radical lifetime and phosphate residue during the degradation of organophosphorus pollutants by activated persulfate in cobalt-based catalysts were solved, achieving efficient degradation and simultaneous removal, selective oxidation of organophosphorus pollutants and phosphate removal, and exhibiting good cycle stability and regeneration performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANSHENG CONSTR NEW TECH GUANGDONG
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-02
Smart Images
Figure CN122124798A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to a cobalt-zirconium bimetallic composite catalyst, its preparation method, and its application. Background Technology
[0002] Organophosphorus pollutants are widely used in flame retardants, pesticides, and other fields, and their migration, transformation, and fate in the aquatic environment have attracted much attention. Studies have shown that organophosphorus pollutants have certain toxicity, environmental persistence, and bioaccumulation, and can be transferred through the food chain, ultimately posing a potential threat to human health. Furthermore, organophosphorus pollutants easily release inorganic phosphates during degradation, leading to secondary environmental problems such as eutrophication. Therefore, developing efficient, green, and safe organophosphorus pollutant removal technologies has significant environmental application value.
[0003] Advanced oxidation processes (AOPs) based on persulfate monosulfate (PMS) activation are among the mainstream technologies for degrading organophosphate pollutants. This type of technology generates highly oxidizing free radicals by activating PMS, which can rapidly mineralize organic pollutants into carbon dioxide and water, showing promising applications in water treatment. Transition metal catalysts, especially cobalt-based catalysts, have been extensively studied due to their excellent activation performance on PMS. However, homogeneous cobalt ion catalysts suffer from difficulties in separation and recovery, and are prone to secondary metal pollution; heterogeneous cobalt-based catalysts (such as cobalt oxides and cobalt hydroxides) have become a current research hotspot due to their higher stability, recyclability, and catalytic activity. Compared to single-metal cobalt oxides, cobalt-based bimetallic or multimetallic catalysts typically exhibit superior catalytic activity and stability, mainly due to the synergistic effect between the metal components. Related studies have shown that, compared with cobalt oxides (such as... Compared to cobalt-based hydroxides (such as...), It exhibits superior PMS activation performance, which is attributed to its unique layered structure, abundant surface hydroxyl groups, and high [efficiency / reduction]. It is closely related to redox activity.
[0004] Although the cobalt-based / PMS system has a good degradation effect on organophosphorus pollutants, the sulfate free radicals generated in the traditional system ( ) and hydroxyl radicals ( Organophosphorus compounds mostly exist in a free state with a short lifespan. In actual water bodies, they are easily quenched by complex water components such as high salinity and natural organic matter, leading to a significant reduction in oxidation efficiency. Simultaneously, the degradation of organophosphorus compounds is usually accompanied by the formation of inorganic phosphates, and the residual soluble phosphates still pose a risk of eutrophication. How to regulate the existence form of free radicals to prolong the lifespan of active species, achieve selective oxidation of target pollutants, and simultaneously remove phosphates generated from organophosphorus degradation remains a key technical challenge.
[0005] Therefore, there is an urgent need to develop a composite material with surface-bound free radicals as the main active species and both adsorption and catalysis functions, so as to achieve efficient degradation of organophosphorus pollutants and simultaneous removal of their mineralization product phosphate. Summary of the Invention
[0006] In view of the above problems, the present invention is proposed to provide a cobalt-zirconium bimetallic composite catalyst, its preparation method and application, which overcomes or at least partially solves the above problems.
[0007] In a first aspect, embodiments of the present invention provide a method for preparing a cobalt-zirconium bimetallic composite catalyst, comprising the following steps:
[0008] S1. Dissolve soluble zirconium salt in deionized water and stir until completely dissolved to obtain a zirconium salt solution; stir the zirconium salt solution at a speed of 500-700 r / min and add alkaline precipitant dropwise to the zirconium salt solution to adjust the pH value of the system to 6.5-7.5 to obtain suspension A;
[0009] S2. The suspension A is transferred into a reaction vessel for hydrothermal treatment. After the reaction is completed, the resulting product is washed and dried to obtain an amorphous product. powder;
[0010] S3, the amorphous The powder was dispersed in ultrapure water by stirring at a speed of 500–700 r / min to obtain an amorphous product. Dispersion;
[0011] S4. Stir the amorphous material at a speed of 500-700 r / min. Dispersion, and towards the amorphous Adding a cobalt salt solution dropwise to the dispersion allows the cobalt ions in the system to react with the cobalt salt solution. The molar ratio of the components is (1-20):1. After mixing evenly, suspension B is obtained. Suspension B is stirred at a speed of 500-700 r / min, and an alkaline precipitant is added dropwise to suspension B to adjust the pH value of the system to 6.5-7.5, thus obtaining suspension C.
[0012] S5. Stir the suspension C at 500-700 r / min for 20-40 min, filter to obtain a precipitate; the precipitate is then washed and dried to obtain... load Cobalt-zirconium bimetallic composite catalyst.
[0013] In one embodiment, the soluble zirconium salt is one of zirconium oxychloride, zirconium nitrate, or zirconium acetate, and the concentration of the zirconium salt solution is 0.05–0.2 mol / L.
[0014] In one embodiment, in steps S2 and S4, the alkaline precipitant is one of ammonia, sodium hydroxide, or sodium carbonate.
[0015] In one embodiment, in step S2, the heating temperature of the hydrothermal treatment is 100-140°C, and the treatment time is 20-28 hours; the drying temperature is 50-70°C, and the drying time is 10-14 hours.
[0016] In one embodiment, the cobalt salt solution is one of cobalt nitrate solution, cobalt chloride solution, or cobalt acetate solution; the concentration of the cobalt salt solution is 8-12 g / L.
[0017] In one implementation, in step S4, the amorphous... The cobalt salt solution is added dropwise to the dispersion over a period of 10–20 min, and the alkaline precipitant is added dropwise to suspension B over a period of 10–20 min.
[0018] In one embodiment, in step S5, the drying temperature is 70–90°C and the drying time is 10–14 hours.
[0019] In one embodiment, cobalt ions in the system and The molar ratio is (5-20):1.
[0020] Secondly, embodiments of the present invention also provide a cobalt-zirconium bimetallic composite catalyst prepared by the above-described method for preparing cobalt-zirconium bimetallic composite catalysts.
[0021] Thirdly, embodiments of the present invention also provide the application of persulfate activated by the above-mentioned cobalt-zirconium bimetallic composite catalyst in the degradation of organophosphorus pollutants in water.
[0022] In one embodiment, the organophosphorus pollutant is at least one of phenylphosphonic acid (PPOA), fenitrothion (FNT), diazinon (DZ), and dimethoate (DT).
[0023] This invention uses a direct precipitation method to prepare load This invention relates to a cobalt-zirconium bimetallic composite catalyst. The direct precipitation method uses water and / or organic solvents as the reaction medium, under specific temperature and pressure conditions, to deposit metal ions as hydroxides onto the support surface. The direct precipitation method is mature and stable, and allows for precise control of the product loading, resulting in a uniform distribution of the active component in the prepared composite catalyst, thus improving the catalytic efficiency of the composite material to a certain extent. This invention eliminates the need for high-temperature calcination, offering advantages such as simple process, mild reaction conditions, and low energy consumption. By controlling parameters such as the cobalt-zirconium molar ratio, reaction pH, and reaction temperature, [the following can be achieved / achieved]. In amorphous Uniform loading on the support is beneficial to improving the catalytic activity and structural stability of the catalyst.
[0024] The cobalt-zirconium bimetallic composite catalyst prepared in this invention utilizes amorphous... The high specific surface area and abundant surface hydroxyl groups promote The high dispersion provides more adsorption sites for organophosphorus pollutants and PMS, significantly improving the catalyst's activation efficiency for PMS and thus enhancing the degradation effect of organophosphorus pollutants. Simultaneously, this composite catalyst can rapidly adsorb and remove phosphates generated during organophosphorus degradation through the specific adsorption between Zr sites and phosphorus-containing functional groups. This achieves efficient degradation of organophosphorus pollutants and simultaneous removal of their mineralization product, phosphate, effectively solving the technical problem of residual phosphates after organophosphorus degradation, which easily leads to eutrophication, in traditional technologies. The catalyst also exhibits good cycle stability and regeneration performance.
[0025] This invention employs amorphous materials. As a carrier, its high specific surface area and abundant surface hydroxyl groups can co-enrich PMS and organophosphorus pollutants on the catalyst surface, promoting the activation of PMS to generate sulfate free radicals ( ), hydroxyl radicals ( Reactive oxygen species, such as phosphorus compounds, mainly exist in the form of surface-bound free radicals. Compared with free radicals in traditional systems, surface-bound free radicals are confined to the catalyst surface, resulting in a significantly longer lifetime. Furthermore, the probability of contact with target pollutants enriched on the catalyst surface is greatly increased, thereby achieving highly efficient and selective oxidation of organophosphorus pollutants. This significantly reduces the interference of coexisting components such as high salinity and natural organic matter in complex water bodies on the oxidation process, and improves the stability of practical applications. Attached Figure Description
[0026] The accompanying drawings, which form part of the specification, are used to provide a further understanding of the embodiments of this application and illustrate the implementation methods of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings:
[0027] Figure 1 Prepared as described in Example 3 of this invention load Cobalt-zirconium bimetallic composite catalyst, prepared in Comparative Example 1 and the preparation of Comparative Example 2 XRD diffraction pattern;
[0028] Figure 2 Prepared as described in Example 3 of this invention load Cobalt-zirconium bimetallic composite catalyst, prepared in Comparative Example 1 and the preparation of Comparative Example 2 Scanning electron microscope images;
[0029] Figure 3 Prepared in Examples 1-6 of this invention load Performance comparison curves of cobalt-zirconium bimetallic composite catalysts in the catalytic degradation of phenylphosphonic acid (PPOA);
[0030] Figure 4 Prepared as described in Example 3 of this invention load Cobalt-zirconium bimetallic composite catalyst, prepared in Comparative Example 1 and the preparation of Comparative Example 2 Performance comparison curves of catalytic degradation of phenylphosphonic acid (PPOA);
[0031] Figure 5 Prepared in Examples 1-6 of this invention load Performance comparison curves of cobalt-zirconium bimetallic composite catalysts for catalytic degradation of phenylphosphonic acid (PPOA) and simultaneous removal of phosphate;
[0032] Figure 6 Prepared as described in Example 3 of this invention load Cobalt-zirconium bimetallic composite catalyst, prepared in Comparative Example 1 and the preparation of Comparative Example 2 Performance comparison curves of degrading phenylphosphonic acid (PPOA) and simultaneously removing phosphate;
[0033] Figure 7 Prepared as described in Example 3 of this invention load Electron paramagnetic resonance (EPR) spectra of cobalt-zirconium bimetallic composite catalysts in PMS system;
[0034] Figure 8 Prepared as described in Example 3 of this invention load Cyclic stability test curves of cobalt-zirconium bimetallic composite catalyst for degradation of phenylphosphonic acid (PPOA);
[0035] Figure 9 Prepared as described in Example 3 of this invention load A comparison of the adsorption efficiencies of cobalt-zirconium bimetallic composite catalysts for different organophosphorus pollutants;
[0036] Figure 10Prepared as described in Example 3 of this invention load Comparison of first-order reaction kinetic rate constants for the degradation of different organophosphorus pollutants by cobalt-zirconium bimetallic composite catalysts. Detailed Implementation
[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0038] The following is combined with Figures 1-10 This invention describes a cobalt-zirconium bimetallic composite catalyst, its preparation method, and its application.
[0039] Unless otherwise specified in the embodiments of the present invention, the techniques or conditions described in the literature in this field or the product instructions shall be followed; if the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased through legitimate channels.
[0040] Example 1
[0041] A method for preparing a cobalt-zirconium bimetallic composite catalyst includes the following steps:
[0042] S1. Dissolve soluble zirconium oxychloride octahydrate in 100 mL of deionized water and stir until completely dissolved to obtain a zirconium oxychloride solution with a concentration of 0.1 mol / L. Stir the zirconium oxychloride solution at 600 r / min and add ammonia water dropwise to the zirconium salt solution to adjust the pH of the system to 7.0 to obtain suspension A.
[0043] S2. The suspension A is transferred to a reaction vessel for hydrothermal treatment at 120°C for 24 hours. After the reaction, the product is washed with ethanol and distilled water until the washing solution is neutral. It is then transferred to an oven and dried at 60°C for 12 hours to obtain an amorphous product. powder;
[0044] S3, Take 0.1g of the amorphous material... The powder was dispersed in 160 mL of ultrapure water at a stirring speed of 600 r / min for 30 min to obtain an amorphous product. Dispersion;
[0045] S4. Stir the amorphous material at 600 r / min. The dispersion was applied to the amorphous material within 15 minutes. A 10 g / L cobalt nitrate solution was added dropwise to the dispersion to allow cobalt ions in the system to react with... The molar ratio of the components was 20:1, and the mixture was thoroughly mixed to obtain suspension B. Suspension B was stirred at 600 r / min, and 1.0 mL of ammonia was added dropwise to suspension B over 15 min to adjust the pH of the system to 7.0, thus obtaining suspension C.
[0046] S5. Stir the suspension C at 600 r / min for 30 min, so that... by Form fully deposited in The carrier surface; after the reaction, the precipitate was obtained by filtration; the precipitate was washed with ultrapure water until the washing solution was neutral, and then dried in an oven at 80°C for 12 hours to obtain the desired product. load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-20.
[0047] Example 2
[0048] A method for preparing a cobalt-zirconium bimetallic composite catalyst, the steps of which are basically the same as those in Example 1, except that in step S4, cobalt ions and... The molar ratio was replaced with 10:1. The resulting... load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-10.
[0049] Example 3
[0050] A method for preparing a cobalt-zirconium bimetallic composite catalyst, the steps of which are basically the same as those in Example 1, except that in step S4, cobalt ions and... The molar ratio was replaced with 5:1. The resulting product... load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-5.
[0051] The sample prepared in Example 3 was analyzed using an X-ray diffractometer. load The phase characterization of the cobalt-zirconium bimetallic composite catalyst (i.e., ZCH-5) was performed, and the results are as follows: Figure 1 As shown.
[0052] The sample prepared in Example 3 was examined using scanning electron microscopy. load The microstructure of the cobalt-zirconium bimetallic composite catalyst (ZCH-5) was analyzed, and the results are as follows: Figure 2 As shown.
[0053] Example 4
[0054] A method for preparing a cobalt-zirconium bimetallic composite catalyst is basically the same as that in Example 1, except that: in step S2, the hydrothermal treatment heating temperature is replaced with 100℃; in step S4, cobalt ions and... The molar ratio was replaced with 2.5:1. The resulting... load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-2.5.
[0055] Example 5
[0056] A method for preparing a cobalt-zirconium bimetallic composite catalyst is basically the same as that in Example 1, except that: in step S2, the hydrothermal treatment heating temperature is replaced with 100℃; in step S4, cobalt ions and... The molar ratio was replaced with 1.67:1. The resulting product... load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-1.67.
[0057] Example 6
[0058] A method for preparing a cobalt-zirconium bimetallic composite catalyst is basically the same as that in Example 1, except that: in step S2, the hydrothermal treatment heating temperature is replaced with 100℃; in step S4, cobalt ions and... The molar ratio was replaced with 1.25:1. The resulting product... load The cobalt-zirconium bimetallic composite catalyst is designated ZCH-1.25.
[0059] Comparative Example 1
[0060] an amorphous The method for preparing the powder includes the following steps:
[0061] S1. Dissolve soluble zirconium oxychloride octahydrate in 100 mL of deionized water and stir until completely dissolved to obtain a zirconium oxychloride solution with a concentration of 0.1 mol / L; stir the zirconium oxychloride solution at 600 r / min and add ammonia water dropwise to the zirconium oxychloride solution to adjust the pH value of the system to 7.0 to obtain a suspension;
[0062] S2. The suspension is transferred to a reaction vessel for hydrothermal treatment at 100°C for 24 hours. After the reaction, the product is washed with ethanol and distilled water until the washing solution is neutral. It is then transferred to an oven and dried at 60°C for 12 hours to obtain an amorphous product. powder.
[0063] The amorphous material prepared in Comparative Example 1 was analyzed using X-ray diffraction. The powder was characterized by phase composition, and the results are as follows: Figure 1 As shown.
[0064] The amorphous material prepared in Comparative Example 1 was examined using scanning electron microscopy. The microstructure of the powder was analyzed, and the results are as follows: Figure 2 As shown.
[0065] Comparative Example 2
[0066] A sort of The preparation method includes the following steps:
[0067] S1. Take 160 mL of ultrapure water, add 1.56 mL of cobalt nitrate solution with a concentration of 10 g / L, stir at 600 r / min, and add ammonia water dropwise to adjust the pH of the system to 9.0. After complete precipitation, a suspension is obtained.
[0068] S2. Stir the suspension at 600 r / min for 30 min. After the reaction is complete, filter to obtain the precipitate. Wash the precipitate with ultrapure water until the washing solution is neutral, and then dry it in an oven at 80°C for 12 h to obtain... powder.
[0069] The sample prepared in Comparative Example 2 was analyzed using X-ray diffraction. The powder was characterized by phase composition, and the results are as follows: Figure 1 As shown.
[0070] The sample prepared by comparative example 2 was examined using scanning electron microscopy. The microstructure of the powder was analyzed, and the results are as follows: Figure 2 As shown.
[0071] X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterization analysis
[0072] Now through Figures 1 to 2 The cobalt-zirconium bimetallic composite catalyst ZCH-5 sample prepared in Example 3 and the sample prepared in Comparative Example 1 were compared. Powder sample, prepared in Comparative Example 2 The samples were characterized and analyzed.
[0073] from Figure 1 As can be seen from the XRD pattern, the sample prepared in Comparative Example 1... Powder samples in The presence of a broad diffuse peak in the range of 20–35° indicates that the sample prepared in Comparative Example 1... It has an amorphous structure. The sample prepared in Comparative Example 2... Sample in Characteristic diffraction peaks appeared at 11.0°, 19.1°, 32.5°, 38.0°, 51.4°, and 61.6°. Meanwhile, the XRD pattern of the cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3 also showed amorphous peaks. diffusion peaks and The characteristic peaks indicate that load A cobalt-zirconium bimetallic composite catalyst was successfully synthesized.
[0074] exist Figure 2 In the figure, Figure a shows the sample prepared in Comparative Example 2. SEM images of the powder samples, Figure b shows the amorphous powder prepared in Comparative Example 1. SEM images of powder samples, Figure c is an SEM image of the cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3.
[0075] As can be seen from Figure a, the material prepared in Comparative Example 2... It consists of regular thin sheets with smooth surfaces; Figure b shows the amorphous material prepared in Comparative Example 1. The particles are irregular and have rough surfaces; as shown in Figure c, the cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3 contains... and They are tightly bound together, exhibiting a relatively loose structure formed by the stacking of two types of particles, which effectively suppresses the self-aggregation of nanoparticles.
[0076] Performance testing and analysis of catalytic degradation of PPOA and simultaneous phosphate removal.
[0077] Prepared using Examples 1-6 load Cobalt-zirconium bimetallic composite catalyst, and amorphous catalyst prepared in Comparative Example 1 Powder samples and those prepared in Comparative Example 2 The powder samples were tested for their catalytic degradation performance of PPOA and their ability to remove phosphate while degrading PPOA.
[0078] Test method: At 25°C, 30 mg of samples (i.e., those prepared in Examples 1-6) were tested. load Cobalt-zirconium bimetallic composite catalyst, and amorphous catalyst prepared in Comparative Example 1 Powder samples and those prepared in Comparative Example 2 The powder sample was dispersed in 100 mL of 5 mg / L phenylphosphonic acid (PPOA), and 0.2 mmol / L permonosulfate (PMS) was added. The mixture was stirred to allow the reaction to proceed. Samples were taken at regular intervals, filtered, and the concentrations of phenylphosphonic acid (PPOA) and phosphate in the solution were measured. The test results are shown below. Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown.
[0079] from Figure 3 , Figure 4 The results show that the products prepared in Examples 1-6 of this invention load The cobalt-zirconium bimetallic composite catalyst showed significantly higher degradation rates of PPOA within 10 minutes compared to the single-component amorphous catalyst. Powder sample (Comparative Example 1) Degradation performance of p-phenylphosphonic acid (PPOA) in powdered samples (Comparative Example 2).
[0080] Among them, the cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3 showed the best degradation performance, with a degradation rate of 99.92% for PPOA within 10 minutes. In contrast, the amorphous catalyst in Comparative Example 1... The degradation rate of PPOA by the powder sample within 10 minutes was 62.82%, compared to Comparative Example 2. The degradation rate of PPOA by the powder sample within 10 minutes was 18.31%.
[0081] The above experiments were all repeated 3 times, and the results were averaged. The error bars represent the standard deviation.
[0082] This invention is achieved through and The composite structure can form a highly efficient and synergistic catalytic system, and by adjusting the Zr / Co molar ratio, a series of composite catalysts with excellent catalytic degradation activity can be prepared. It can be seen that the present invention has universality, stability and superiority.
[0083] from Figure 5 , Figure 6 The results show that the phosphate concentration in the PPOA solution was 0 mg / L before the reaction, and the phosphate concentration first increased and then decreased during the reaction. The solutions prepared in Examples 1-6 of this invention... load Both cobalt-zirconium bimetallic composite catalysts exhibit excellent simultaneous phosphate removal capabilities, with phosphate removal rates significantly higher than those of single-component amorphous catalysts. Powder sample (Comparative Example 1) Phosphate removal rate of powder sample (Comparative Example 2).
[0084] The cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3 achieved a phosphate removal rate of 98.52% within 60 min. Comparative Example 1 used an amorphous catalyst... The powder sample achieved a phosphate removal rate of 83.66% within 60 minutes, compared to Comparative Example 2. The phosphate removal rate of the powder sample was only 16.34% within 60 min. After PPOA degradation in the ZCH-5 / PMS system, the phosphate concentration decreased to 0.015 mg / L, and the total phosphorus concentration (as P) in the system was 0.005 mg / L, which is lower than the total phosphorus limit (as P) of Class I water specified in the "Surface Water Environmental Quality Standard" (GB 3838—2002) of ≤0.02 mg / L.
[0085] In this invention load The cobalt-zirconium bimetallic composite catalyst exhibits excellent simultaneous phosphate removal performance while catalyzing the degradation of PPOA.
[0086] This invention will... and The method of constructing a bifunctional "adsorption-catalysis" system is universal. By adjusting the cobalt-zirconium molar ratio, a series of composite catalysts with both high-efficiency degradation and simultaneous phosphorus removal performance can be prepared.
[0087] Identification of active species
[0088] Electron paramagnetic resonance (EPR) technology was used to analyze the materials prepared in this invention. load The reactive oxygen species generated in the cobalt-zirconium bimetallic composite catalyst activated in the persulfate (ZCH / PMS) system were identified, and the results are attached. Figure 7 As shown.
[0089] When DMPO is used as a spin trapping agent, it is detected that and The characteristic signals initially confirmed the generation of [something] in the system. and To further distinguish between diffuse free radicals in solution and catalyst surface-bound free radicals, fluoride ions were introduced into the system. ).like Figure 7 As shown, add back, and The signal strength was significantly enhanced, indicating that the system generated and It mainly exists in the form of surface-bound free radicals. Furthermore, when DMPO is used as a scavenger, [other substances] were also detected. The characteristic signal was detected when TEMP was used as the capture agent. The characteristic triplet signal confirmed the simultaneous generation of non-radical active species in the system. Combined with the EPR analysis results, it can be seen that the ZCH / PMS system mainly contains surface-bound species. and ,as well as and The aforementioned active species collectively participate in the catalytic degradation process of PPOA.
[0090] Cyclic stability test
[0091] Test method: The cobalt-zirconium bimetallic composite catalyst ZCH-5, after the above-mentioned catalytic degradation performance test of PPOA, was recovered, washed, dried, and the above-mentioned catalytic degradation performance test of PPOA was repeated. The test results are as follows: Figure 8 As shown.
[0092] from Figure 8 As can be seen, after three cycles, the removal rate of PPOA by ZCH-5 remained above 79.08%. After regeneration treatment with NaOH solution, the degradation rate of PPOA by ZCH-5 rebounded to 92.35% in the sixth cycle, indicating that the catalyst has good cycle stability and regeneration performance.
[0093] Adsorption efficiency test for different organophosphorus pollutants
[0094] To further evaluate the removal performance of the cobalt-zirconium bimetallic composite catalyst of the present invention for different organophosphorus pollutants, phenylphosphonic acid (PPOA), fenitrothion (FNT), diazinon (DZ), and dimethoate (DT) were selected as target pollutants, and adsorption and degradation experiments were carried out.
[0095] Test method: The cobalt-zirconium bimetallic composite catalyst ZCH-5 prepared in Example 3 was used as the test catalyst. In the test system, the catalyst dosage was 300 mg / L, the persulfate (PMS) dosage was 0.2 mmol / L, the target pollutant concentration was 5 mg / L, and the initial pH of the system was 6.8. The test results are as follows: Figure 9 As stated above.
[0096] from Figure 9It can be seen that the adsorption efficiency of the four organophosphorus pollutants on the surface of the cobalt-zirconium bimetallic composite catalyst ZCH-5 is in the following order: PPOA (60.2%) > DZ (39.5%) > FNT (28.5%) > DT (19.5%). The cobalt-zirconium bimetallic composite catalyst ZCH-5 exhibits the best adsorption capacity for PPOA, mainly due to the formation of strongly coordinated PO-Zr bonds between the phosphonic acid groups in PPOA and the Zr-OH sites on the catalyst surface. In contrast, the phosphorus-containing groups of DZ, FNT, and DT do not contain deprotonated oxygen atoms, and therefore cannot form strong coordinated bonds with the Zr sites on the catalyst surface, resulting in lower adsorption efficiency of these pollutants by the cobalt-zirconium bimetallic composite catalyst ZCH-5.
[0097] Figure 10 The first-order kinetic fitting curves of the degradation reactions of four organophosphorus pollutants in the ZCH / PMS system are shown. The figure shows that the order of reaction rate constants (kobs) is: PPOA > DZ > FNT > DT, which is basically consistent with the order of adsorption efficiency of the four organophosphorus pollutants by the cobalt-zirconium bimetallic composite catalyst ZCH-5. Notably, the kobs value of PPOA is significantly higher than that of the other three pollutants, indicating that the ZCH / PMS system has a significant selective degradation advantage for PPOA, further confirming that the specific adsorption between pollutant molecules and the catalyst surface is the key factor determining its degradation efficiency.
[0098] The above results indicate that the ZCH / PMS system exhibits selectivity in the degradation of organophosphorus pollutants. This selectivity is dominated by the specific coordination between pollutant molecules and Zr sites on the catalyst surface, rather than solely relying on hydrophobic interactions.
[0099] This invention uses a direct precipitation method to prepare load This invention relates to a cobalt-zirconium bimetallic composite catalyst. The direct precipitation method uses water and / or organic solvents as the reaction medium, under specific temperature and pressure conditions, to deposit metal ions as hydroxides onto the support surface. The direct precipitation method is mature and stable, and allows for precise control of the product loading, resulting in a uniform distribution of the active component in the prepared composite catalyst, thus improving the catalytic efficiency of the composite material to a certain extent. This invention eliminates the need for high-temperature calcination, offering advantages such as simple process, mild reaction conditions, and low energy consumption. By controlling parameters such as the cobalt-zirconium molar ratio, reaction pH, and reaction temperature, [the following can be achieved / achieved]. In amorphous Uniform loading on the support is beneficial to improving the catalytic activity and structural stability of the catalyst.
[0100] The cobalt-zirconium bimetallic composite catalyst prepared in this invention utilizes amorphous... The high specific surface area and abundant surface hydroxyl groups promote The high dispersion provides more adsorption sites for organophosphorus pollutants and PMS, significantly improving the catalyst's activation efficiency for PMS and thus enhancing the degradation effect of organophosphorus pollutants. Simultaneously, this composite catalyst can rapidly adsorb and remove phosphates generated during organophosphorus degradation through the specific adsorption between Zr sites and phosphorus-containing functional groups. This achieves efficient degradation of organophosphorus pollutants and simultaneous removal of their mineralization product, phosphate, effectively solving the technical problem of residual phosphates after organophosphorus degradation, which easily leads to eutrophication, in traditional technologies. The catalyst also exhibits good cycle stability and regeneration performance.
[0101] Most importantly, this invention employs an amorphous process. As a carrier, its high specific surface area and abundant surface hydroxyl groups can co-enrich PMS and organophosphorus pollutants on the catalyst surface, promoting the activation of PMS to generate sulfate free radicals ( ), hydroxyl radicals ( Reactive oxygen species, such as phosphorus compounds, mainly exist in the form of surface-bound free radicals. Compared with free radicals in traditional systems, surface-bound free radicals are confined to the catalyst surface, resulting in a significantly longer lifetime. Furthermore, the probability of contact with target pollutants enriched on the catalyst surface is greatly increased, thereby achieving highly efficient and selective oxidation of organophosphorus pollutants. This significantly reduces the interference of coexisting components such as high salinity and natural organic matter in complex water bodies on the oxidation process, and improves the stability of practical applications.
[0102] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A method for preparing a cobalt-zirconium bimetallic composite catalyst, characterized in that, Includes the following steps: S1. Dissolve soluble zirconium salt in deionized water and stir until completely dissolved to obtain a zirconium salt solution; stir the zirconium salt solution at a speed of 500-700 r / min and add alkaline precipitant dropwise to the zirconium salt solution to adjust the pH value of the system to 6.5-7.5 to obtain suspension A; S2. The suspension A is transferred into a reaction vessel for hydrothermal treatment. After the reaction is completed, the resulting product is washed and dried to obtain an amorphous product. powder; S3, the amorphous The powder was dispersed in ultrapure water by stirring at a speed of 500–700 r / min to obtain an amorphous product. Dispersion; S4. Stir the amorphous material at a speed of 500-700 r / min. Dispersion, and towards the amorphous Adding a cobalt salt solution dropwise to the dispersion allows the cobalt ions in the system to react with the cobalt salt solution. The molar ratio of the components is (1-20):
1. After mixing evenly, suspension B is obtained. Suspension B is stirred at a speed of 500-700 r / min, and an alkaline precipitant is added dropwise to suspension B to adjust the pH value of the system to 6.5-7.5, thus obtaining suspension C. S5. Stir the suspension C at 500-700 r / min for 20-40 min, then filter to obtain the precipitate; The precipitate was washed and dried to obtain load Cobalt-zirconium bimetallic composite catalyst.
2. The preparation method of the cobalt-zirconium bimetallic composite catalyst according to claim 1, characterized in that: The soluble zirconium salt is one of zirconium oxychloride, zirconium nitrate, or zirconium acetate, and the concentration of the zirconium salt solution is 0.05–0.2 mol / L.
3. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 1 or 2, characterized in that: In steps S2 and S4, the alkaline precipitant is one of ammonia, sodium hydroxide, or sodium carbonate.
4. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 3, characterized in that: In step S2, the heating temperature of the hydrothermal treatment is 100-140℃, and the treatment time is 20-28h; the drying temperature is 50-70℃, and the drying time is 10-14h.
5. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 1, 2, or 4, characterized in that: The cobalt salt solution is one of cobalt nitrate solution, cobalt chloride solution, or cobalt acetate solution; the concentration of the cobalt salt solution is 8-12 g / L.
6. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 5, characterized in that: In step S4, the amorphous material is... The cobalt salt solution is added dropwise to the dispersion over a period of 10–20 min, and the alkaline precipitant is added dropwise to suspension B over a period of 10–20 min.
7. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 6, characterized in that: In step S5, the drying temperature is 70-90°C and the drying time is 10-14 hours.
8. The method for preparing the cobalt-zirconium bimetallic composite catalyst according to claim 1, characterized in that: Cobalt ions in the system The molar ratio is (5-20):
1.
9. A cobalt-zirconium bimetallic composite catalyst, characterized in that, It is prepared by the method of any one of claims 1 to 8.
10. The application of the cobalt-zirconium bimetallic composite catalyst as described in claim 9 in the activation of persulfate for the degradation of organophosphorus pollutants in water.