Silver phosphate catalysts and methods of use
The preparation of porous silver phosphate catalysts with porous structures through photocuring additive manufacturing technology solves the problems of low catalytic efficiency and difficulty in recovery in the prior art, and achieves efficient use of the catalyst and multiple activity recovery.
Patent Information
- Application Number
- CN202411404151.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-02-18
AI Technical Summary
The existing silver phosphate catalyst has low catalytic efficiency and cannot be used again after recycling, which has problems such as photocorrosion, poor cycle stability and high cost.
The silver skeleton with porous structures was prepared by photocuring additive manufacturing technology, and the silver phosphate catalyst was prepared by sonication and in situ synthesis in dilute HNO3 and NaH2PO4 solutions. This method does not require secondary negative loading and catalytic activity can be restored by simple immersion treatment.
The catalytic efficiency and cycle stability of the silver phosphate catalyst are improved, multiple uses and activity recovery of the catalyst are achieved, and the recovery cost is reduced.
Smart Images
Figure CN119455993A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of catalytic technology, and more specifically to a silver phosphate catalyst and a use method thereof. Background Art
[0002] The degradation and purification of industrial wastewater has always been a key issue for my country, the world's largest industrial printing and dyeing country. However, no matter whether physical, chemical or biological methods are used, there are problems of incomplete degradation, high cost and low efficiency. Silver phosphate (Ag3PO4) photocatalyst has a high quantum yield and extremely strong photocatalytic activity under visible light irradiation. It can be used as a new generation of visible light catalytic material to efficiently degrade industrial wastewater. However, in experiments, it was found that silver phosphate has the disadvantages of photocorrosion, poor cycle stability (usually less than 10 times) and high cost. And due to the limitations of loading technology, the catalyst is usually limited to strips and ribbons. This type of catalyst has a small specific surface area and low catalytic efficiency. It cannot be reactivated and put into use after recovery. Generally, the precious metals in it are recovered by electrochemical method or active wet method after failure. Summary of the invention
[0003] The embodiments of the present invention provide a silver phosphate catalyst and a method of using the same, which are used to solve the problems of low catalytic efficiency and inability to reuse the existing silver phosphate catalyst after recovery.
[0004] The embodiment of the present invention provides a silver phosphate catalyst, comprising:
[0005] Models with different porosities were selected to prepare a mixture green body containing silver and resin based on the light-curing additive manufacturing technology, and the mixture green body was degreased and sintered to obtain a pure silver skeleton;
[0006] The pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and subjected to ultrasonic treatment for a set time, and the pure silver skeleton after ultrasonic treatment is cleaned and dried to obtain an initial sample;
[0007] The initial sample was immersed in NaH2PO4 solutions of different concentrations and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% was added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst was cleaned and dried.
[0008] Preferably, the porosity of the pure silver skeleton is 80% to 90%.
[0009] Preferably, the pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and subjected to ultrasonic treatment for a set time, and the pure silver skeleton after ultrasonic treatment is cleaned and dried to obtain an initial sample, which specifically includes:
[0010] The pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and ultrasonically treated for 15 minutes. The pure silver skeleton after ultrasonic treatment is washed with pure water or anhydrous ethanol and dried to obtain the initial sample.
[0011] Preferably, the initial sample is immersed in NaH2PO4 solution of different concentrations for ultrasonic treatment for a set time, then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment, and after the ultrasonic treatment, the silver phosphate catalyst is obtained by washing and drying, which specifically includes:
[0012] The initial sample is immersed in a NaH2PO4 solution with a concentration of 5 mMol / L and subjected to ultrasonic treatment for a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment for 5 minutes. After the ultrasonic treatment, the sample is washed and dried to obtain a silver phosphate catalyst.
[0013] Preferably, the concentration of the NaH2PO4 solution is 1 mMol / L to 20 mMol / L;
[0014] The time for ultrasonic treatment by adding H2O2 solution with a volume fraction of 10% is 4 to 10 minutes.
[0015] The embodiment of the present invention provides a method for using a silver phosphate catalyst, comprising:
[0016] Adding simulated sewage and the first-time silver phosphate catalyst into a container in sequence, irradiating the container with a xenon lamp, taking out a test solution from the container at a set interval, and obtaining a degradation rate of the test solution based on a spectrophotometer;
[0017] When the degradation rate is less than a first set value, the silver phosphate catalyst is determined to be ineffective, the ineffective silver phosphate catalyst is cleaned and dried, connected to an anode of an electrolytic power source, the cathode of the electrolytic power source is connected to a titanium sheet, and the electrolytic power source is set in a nitric acid solution for electrolysis;
[0018] After electrolysis, the silver phosphate catalyst is immersed in NaH2PO4 solutions of different concentrations and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst is cleaned and dried to obtain the silver phosphate catalyst with restored catalytic activity.
[0019] Preferably, the cathode of the electrolytic power supply is connected to the titanium sheet, and the electrolytic power supply is arranged in a nitric acid solution for electrolysis, specifically comprising:
[0020] The electrolysis power source was set in a nitric acid solution with a concentration of 30 Mol / L for 10 seconds, wherein the voltage of the electrolysis power source was 1.5 V and the electrolysis temperature was 30°C.
[0021] Preferably, the voltage of the electrolysis power supply is 1V to 3V; the electrolysis temperature is 20 to 50°C, and the electrolysis time is 5s to 30s.
[0022] Preferably, when the degradation rate is less than 60%, it is determined that the silver phosphate catalyst is ineffective;
[0023] The simulated sewage is any one of a 30 mg / L Rhodamine B solution, a 20 mg / L MO solution, a 20 mg / L MB solution, and a 20 mg / L RhB solution.
[0024] Preferably, after the ultrasonic treatment is followed by washing and drying to obtain the silver phosphate catalyst with restored catalytic activity, the method further comprises:
[0025] Simulated sewage and the silver phosphate catalyst with restored catalytic activity are added into a container in sequence, the container is irradiated with a xenon lamp, the test solution is taken out from the container for the first time at a set interval and the degradation rate is obtained. If the degradation rate is less than 80%, it is determined that the silver phosphate catalyst with restored catalytic activity is invalid.
[0026] The silver phosphate catalyst provided in the embodiment of the present invention uses models with different porosities, and prepares a mixture green body containing silver and resin based on the light-curing additive manufacturing technology. The mixture green body is degreased and sintered to obtain a pure silver skeleton; the pure silver skeleton is immersed in a dilute HNO3 solution with a concentration of 5% and ultrasonically treated for a set time, and the pure silver skeleton after ultrasonic treatment is cleaned and dried to obtain an initial sample; the initial sample is immersed in a NaH2PO4 solution with different concentrations and ultrasonically treated for a set time, and a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment, and the silver phosphate catalyst is cleaned and dried after ultrasonic treatment. Based on the light-curing additive manufacturing technology and the in-situ synthesis technology, it has a convenient preparation process and does not require secondary negative loading; furthermore, the carrier of the silver phosphate catalyst is a porous structure, and the proportion of effective active sites that can carry out catalytic reactions is large, which can provide a reaction speed and high-speed explanation of industrial wastewater; further, when the silver phosphate catalyst fails, the catalytic activity can be restored by simple immersion treatment, avoiding the problem of high cost recovery of the failed silver phosphate catalyst in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0028] Figure 1A schematic diagram of a process for preparing a silver phosphate catalyst provided in an embodiment of the present invention;
[0029] Figure 2 A schematic diagram of a scanning electron microscope showing the initial state of a silver phosphate catalyst provided in an embodiment of the present invention;
[0030] Figure 3 A schematic diagram of a scanning electron microscope showing the silver phosphate catalyst provided in an embodiment of the present invention after being recycled 20 times;
[0031] Figure 4 A schematic diagram of a scanning electron microscope showing the silver phosphate catalyst provided in an embodiment of the present invention after being recycled 50 times;
[0032] Figure 5 A schematic front view of a silver phosphate catalyst provided in an embodiment of the present invention;
[0033] Figure 6 A schematic top view of a silver phosphate catalyst provided in an embodiment of the present invention;
[0034] Figure 7 A schematic flow chart of a method for using a silver phosphate catalyst provided in an embodiment of the present invention; DETAILED DESCRIPTION
[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0036] The embodiment of the present invention provides a silver phosphate catalyst, and the preparation method thereof comprises the following steps:
[0037] Step 101, selecting models with different porosities, and preparing a mixture green body containing silver and resin based on a light-curing additive manufacturing technology, wherein the mixture green body is degreased and sintered to obtain a pure silver skeleton;
[0038] Step 102, immersing the pure silver skeleton in a diluted HNO3 solution with a concentration of 5% and performing ultrasonic treatment for a set time, and washing and drying the pure silver skeleton after the ultrasonic treatment to obtain an initial sample;
[0039] Step 103, immersing the initial sample in NaH2PO4 solutions of different concentrations for ultrasonic treatment for a set time, adding H2O2 solution with a volume fraction of 10% for ultrasonic treatment, and washing and drying after ultrasonic treatment to obtain a silver phosphate catalyst.
[0040] In step 101, models with different porosities are selected, and a mixture of silver and resin is prepared based on the light-curing additive manufacturing technology. A pure silver skeleton is obtained after degreasing and sintering, and the porosity of the pure silver skeleton is 80%-90%.
[0041] It should be noted that, in practical applications, the photocurable materials used in photocurable additive manufacturing technology include photosensitive resin, silver powder, dispersant and other organic solvents.
[0042] In step 102, the pure silver skeleton obtained in step 101 is immersed in a 5% dilute HNO3 solution and ultrasonically treated for 15 minutes, then the pure silver skeleton is taken out and cleaned with pure water or anhydrous ethanol, and dried to obtain an initial sample.
[0043] In step 103, the initial sample is immersed in a NaH2PO4 solution with a concentration of 1mMol / L to 20mMol / L and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% is added to react for 4 to 10 minutes under ultrasonic conditions. After the reaction is completed, the reacted sample is removed, cleaned and dried to obtain a silver phosphate catalyst.
[0044] It should be noted that, in practical applications, the concentration of the NaH2PO4 solution may be 5 mMol / L; and the ultrasonic treatment time for adding a 10% volume fraction H2O2 solution is 5 min.
[0045] The whiskers of silver phosphate catalyst obtained for the first time are as follows Figure 2 As shown, the silver phosphate catalyst provided in the embodiment of the present invention is based on photocuring additive manufacturing technology and in-situ synthesis technology, and has a convenient preparation process without the need for secondary negative loading; furthermore, the carrier of the silver phosphate catalyst is a porous structure, and the proportion of effective active sites that can carry out catalytic reactions is large, which can increase the reaction speed and perform high-speed decomposition of industrial wastewater; further, when the silver phosphate catalyst fails, the catalytic activity can be restored by a simple immersion treatment, avoiding the problem of high-cost recovery of the failed silver phosphate catalyst in the prior art.
[0046] Based on the silver phosphate catalyst provided in the above embodiment, the present invention also provides a method for using the silver phosphate catalyst, specifically, Figure 7 As shown, the method of use includes the following steps:
[0047] Step 201, adding simulated sewage and a first-time silver phosphate catalyst into a container in sequence, irradiating the container with a xenon lamp, taking out a test solution from the container at a set interval, and obtaining a degradation rate of the test solution based on a spectrophotometer detection;
[0048] Step 202, when the degradation rate is less than the first set value, it is determined that the silver phosphate catalyst is invalid, the invalid silver phosphate catalyst is cleaned and dried, connected to the anode of the electrolytic power supply, the cathode of the electrolytic power supply is connected to the titanium sheet, and the electrolytic power supply is set in a nitric acid solution for electrolysis;
[0049] Step 203, immersing the electrolyzed silver phosphate catalyst in NaH2PO4 solutions of different concentrations for ultrasonic treatment for a set time, adding a 10% volume fraction H2O2 solution for ultrasonic treatment, and washing and drying after ultrasonic treatment to obtain the silver phosphate catalyst with restored catalytic activity.
[0050] In step 201, the provided simulated sewage is added to a container, and then the silver phosphate catalyst prepared in the above steps is added to the container, the container is irradiated with a xenon lamp, and the test solution is taken out from the container at a set time for spectrophotometric detection. The degradation rate corresponding to each test solution taken out can be determined according to the spectrophotometric detection.
[0051] In the embodiment of the present invention, if the silver phosphate catalyst is used for the first time, the degradation rate of the test solution taken out for the first time according to the set time will not be less than 90%, and the degradation rate of the test solution taken out for the twentieth time according to the set time will not be less than 80%. The whiskers of the silver phosphate catalyst used for 20 times are as follows: Figure 3 As shown; the degradation rate of the test solution taken out for the fiftieth time according to the set time will not be less than 55%, and the whiskers of the silver phosphate catalyst used for 50 times are as shown Figure 4 shown.
[0052] Specifically, the simulated sewage in this embodiment can be a 30 mg / L Rhodamine B solution.
[0053] In step 202, after obtaining the corresponding degradation rate according to the test solution each time, if it is determined that the degradation rate corresponding to the current test solution is less than the first set value, it can be determined that the silver phosphate catalyst is ineffective.
[0054] The first set value here is 60%, that is, when the degradation rate of the test solution taken out according to the set time is less than 60%, it is determined that the silver phosphate catalyst is ineffective.
[0055] The silver phosphate catalyst provided in the embodiment of the present invention has the most important feature of being reusable, which solves the problem in the prior art that the silver phosphate catalyst cannot be reactivated for use. When it is determined that the silver phosphate catalyst has failed, the failed silver phosphate catalyst is cleaned and dried, and connected to the anode of the electrolytic power supply. In this embodiment, the cathode of the electrolytic power supply is connected to the titanium sheet; then the electrolytic power supply is placed in a nitric acid solution for electrolysis, and the electrolysis process will dissolve the failed silver phosphate catalyst connected to the anode.
[0056] Specifically, the concentration of the nitric acid solution is 10 to 100 ml / L, the voltage of the electrolysis power supply is 1 V to 3 V, the electrolysis temperature is 20 to 50° C., and the electrolysis time is 5 s to 30 s.
[0057] In the above embodiment, the concentration of the nitric acid solution is 30 Mol / L, the electrolytic power supply is placed in the nitric acid solution for electrolysis for 10 seconds, the voltage of the electrolytic power supply is 1.5V, and the electrolysis temperature is 30°C.
[0058] In step 203, after the failed silver phosphate catalyst is electrolyzed, the operation in the above step 103 can be repeated, that is, the electrolyzed silver phosphate catalyst is immersed in NaH2PO4 solutions of different concentrations and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst is cleaned and dried to obtain a silver phosphate catalyst with restored catalytic activity.
[0059] The specific content of this step can refer to the above embodiment.
[0060] In the embodiment of the present invention, the silver phosphate catalyst with restored catalytic activity can be obtained through step 203. In practical applications, since the failed silver phosphate catalyst can restore its catalytic activity through the above steps 202-203, but the number of times the failed silver phosphate catalyst can restore its catalytic activity is limited, when the silver phosphate catalyst with restored catalytic activity is used again, if the degradation rate of the test solution taken out for the first time according to the set time is less than 80%, it can be determined that the silver phosphate catalyst with restored catalytic activity is invalid.
[0061] It should be noted that the silver phosphate catalyst provided in the embodiment of the present invention has a degradation rate of not less than 92%, 90% and 95% for 20 mg / L MO, 20 mg / L MB, or 20 mg / L RhB when used for the first time; after the silver phosphate catalyst is circulated 20 times, its degradation rate is not less than 85%, 81% and 91% respectively; after the silver phosphate catalyst is circulated 50 times, its degradation rate is not less than 60%, 55% and 72% respectively; further, after the silver phosphate catalyst fails and the silver phosphate catalyst with restored catalytic activity is obtained through the above steps, when degrading 20 mg / L MO, 20 mg / L MB, or 20 mg / L RhB, its first degradation rate is not less than 85%; after 20 cycles, the degradation rate is not less than 75%; and after the silver phosphate catalyst fails for the first time, it can be effectively activated at least 10 times through the above steps, that is, the silver phosphate catalyst can be recycled at least 10 times.
[0062] In summary, the silver phosphate catalyst provided in the embodiment of the present invention is based on photocuring additive manufacturing technology and in-situ synthesis technology, and has a convenient preparation process without the need for secondary negative loading; furthermore, the carrier of the silver phosphate catalyst has a porous structure, and a large proportion of effective active sites that can carry out catalytic reactions, which can increase the reaction speed and allow high-speed decomposition of industrial wastewater; further, when the silver phosphate catalyst fails, the catalytic activity can be restored by a simple immersion treatment, thereby avoiding the problem of high-cost recovery of failed silver phosphate catalysts in the prior art.
[0063] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0064] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A silver phosphate catalyst, characterized in that include: Models with different porosities were selected to prepare a mixture green body containing silver and resin based on the light-curing additive manufacturing technology, and the mixture green body was degreased and sintered to obtain a pure silver skeleton; The pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and subjected to ultrasonic treatment for a set time, and the pure silver skeleton after ultrasonic treatment is cleaned and dried to obtain an initial sample; The initial sample was immersed in NaH2PO4 solutions of different concentrations and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% was added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst was cleaned and dried.
2. The silver phosphate catalyst according to claim 1, characterized in that The porosity of the pure silver skeleton is 80% to 90%.
3. The silver phosphate catalyst according to claim 1, characterized in that The pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and subjected to ultrasonic treatment for a set time, and the pure silver skeleton after ultrasonic treatment is cleaned and dried to obtain an initial sample, which specifically includes: The pure silver skeleton is immersed in a diluted HNO3 solution with a concentration of 5% and ultrasonically treated for 15 minutes. The pure silver skeleton after ultrasonic treatment is washed with pure water or anhydrous ethanol and dried to obtain the initial sample.
4. The silver phosphate catalyst according to claim 1, characterized in that The initial sample is immersed in NaH2PO4 solution of different concentrations for ultrasonic treatment according to a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst is cleaned and dried to obtain the silver phosphate catalyst, which specifically includes: The initial sample is immersed in a NaH2PO4 solution with a concentration of 5 mMol / L and subjected to ultrasonic treatment for a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment for 5 minutes. After the ultrasonic treatment, the sample is cleaned and dried to obtain a silver phosphate catalyst.
5. The silver phosphate catalyst according to claim 1, characterized in that The concentration of the NaH2PO4 solution is 1 mMol / L to 20 mMol / L; The time for ultrasonic treatment by adding H2O2 solution with a volume fraction of 10% is 4 to 10 minutes.
6. A method for using a silver phosphate catalyst, characterized in that: include: Adding simulated sewage and the first-time silver phosphate catalyst into a container in sequence, irradiating the container with a xenon lamp, taking out a test solution from the container at a set interval, and obtaining a degradation rate of the test solution based on a spectrophotometer; When the degradation rate is less than a first set value, the silver phosphate catalyst is determined to be ineffective, the ineffective silver phosphate catalyst is cleaned and dried, connected to an anode of an electrolytic power source, the cathode of the electrolytic power source is connected to a titanium sheet, and the electrolytic power source is set in a nitric acid solution for electrolysis; After electrolysis, the silver phosphate catalyst is immersed in NaH2PO4 solutions of different concentrations and ultrasonically treated for a set time, and then a H2O2 solution with a volume fraction of 10% is added for ultrasonic treatment. After the ultrasonic treatment, the silver phosphate catalyst is cleaned and dried to obtain the silver phosphate catalyst with restored catalytic activity.
7. The method of use according to claim 6, characterized in that: The cathode of the electrolytic power supply is connected to the titanium sheet, and the electrolytic power supply is arranged in a nitric acid solution for electrolysis, specifically comprising: The electrolysis power source was set in a nitric acid solution with a concentration of 30 Mol / L for 10 seconds, wherein the voltage of the electrolysis power source was 1.5 V and the electrolysis temperature was 30°C.
8. The method of use according to claim 6, characterized in that: The voltage of the electrolysis power supply is 1V to 3V; the electrolysis temperature is 20 to 50°C, and the electrolysis time is 5s to 30s.
9. The method of use according to claim 6, characterized in that: When the degradation rate is less than 60%, it is determined that the silver phosphate catalyst is ineffective; The simulated sewage is any one of a 30 mg / L Rhodamine B solution, a 20 mg / L MO solution, a 20 mg / L MB solution, and a 20 mg / L RhB solution.
10. The method of use according to claim 6, characterized in that: After the ultrasonic treatment, cleaning and drying to obtain the silver phosphate catalyst with restored catalytic activity, the method further comprises: Simulated sewage and the silver phosphate catalyst with restored catalytic activity are added into a container in sequence, the container is irradiated with a xenon lamp, the test solution is taken out from the container for the first time at a set interval and the degradation rate is obtained. If the degradation rate is less than 80%, it is determined that the silver phosphate catalyst with restored catalytic activity is invalid.