Activation method of inactivated palladium-carbon catalyst

Abstract

The invention discloses an activation method of an inactivated palladium-carbon catalyst, which specifically comprises the following steps: sintering the inactivated palladium-carbon catalyst, and purging with nitrogen to obtain a primarily sintered palladium-carbon catalyst; putting the primarily sintered palladium-carbon catalyst into an ethanol-water solution for ultrasonic treatment, filtering and then carrying out secondary sintering to obtain a secondarily sintered palladium-carbon catalyst; soaking the secondarily-burnt palladium-carbon catalyst in hydrogen peroxide, stirring, and carrying out light treatment to obtain a primarily-activated palladium-carbon catalyst; stirring the preliminarily activated palladium-carbon catalyst, filtering, soaking in a palladium acetate solution, stirring, standing, and drying to obtain a coated palladium-carbon catalyst; and sintering the coated palladium-carbon catalyst, soaking the coated palladium-carbon catalyst in a reducing agent solution for reaction, and filtering to obtain the activated palladium-carbon catalyst. According to the activation method, damage to the activated carbon in the deposited carbon removal process is reduced, the stability of an activated carbon carrier is improved, meanwhile, secondary loading is formed by deposition of palladium acetate with residual deposited carbon as a carrier, surface covering is formed on the palladium element, and the activity is recovered and improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst activation, and particularly relates to a method for activating a deactivated palladium-carbon catalyst. Background Art

[0002] A palladium-carbon catalyst is a supported catalyst formed by loading metallic palladium onto activated carbon. Palladium is its active component, and activated carbon serves as the carrier, providing a large specific surface area for palladium, enabling it to fully exert its catalytic effect; in a catalytic reaction, the palladium atoms of the palladium-carbon catalyst can interact with reactant molecules. By adsorbing the reactant molecules, the reactant molecules are activated and transformed on the palladium surface, reducing the activation energy of the reaction, thereby accelerating the progress of the reaction. For example, in a hydrogenation reaction, hydrogen molecules are adsorbed on the palladium surface, and these hydrogens undergo an addition reaction with unsaturated compounds adsorbed on the palladium surface to achieve the hydrogenation process.

[0003] Generally speaking, there are various reasons for the deactivation of palladium-carbon catalysts, including the loss of active components, poisoning, blockage, and sintering. Among them, blockage is a relatively common deactivation phenomenon, where by-products or deposits generated during the reaction block the pore structure of the catalyst carrier, forming carbon deposits in the pores, reducing the surface area and activity of the catalyst. Currently, palladium-carbon catalysts containing carbon deposits are usually calcined to remove surface impurities to restore their catalytic activity. However, the high-temperature treatment process of calcination not only has an effect on removing carbon deposits but also affects the activated carbon carrier, causing damage to the catalyst carrier, resulting in poor recovery of palladium-carbon catalysts. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for activating a deactivated palladium-carbon catalyst, which improves the catalytic activity of the catalyst.

[0005] The technical solution adopted by the present invention is that the method for activating a deactivated palladium-carbon catalyst is specifically implemented according to the following steps: Step 1: Sinter the deactivated palladium-carbon catalyst, and then purge it with nitrogen to obtain a preliminarily sintered palladium-carbon catalyst; Step 2: Put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment, filter it, and then perform secondary sintering. After cooling, a secondarily sintered palladium-carbon catalyst is obtained; Step 3: Immerse the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir it, and then perform light treatment to obtain a preliminarily activated palladium-carbon catalyst; Step 4: Stir the preliminarily activated palladium-carbon catalyst, filter it, immerse it in a palladium acetate solution and stir evenly, and then dry it after standing to obtain a coated palladium-carbon catalyst; Step 5: Sinter the coated palladium-carbon catalyst, and then immerse it in a reducing agent solution for reaction. After filtering, an activated palladium-carbon catalyst is obtained.

[0006] The features of the present invention also lie in that In Step 1, the sintering temperature is 200 - 250°C, the sintering time is 2 - 4 h, the temperature of nitrogen purging is 20 - 40°C; the time of nitrogen purging is 2 - 3 h.

[0007] In Step 2, the ultrasonic frequency is 80 - 100 kHz, the ultrasonic temperature is 20 - 40°C, and the ultrasonic time is 20 - 30 min. The concentration of the initially sintered palladium - carbon catalyst in the ethanol - aqueous solution is 500 - 800 g / L; the temperature of the secondary sintering is 100 - 120°C; the time of the secondary sintering is 2 - 4 h.

[0008] In Step 3, the mass ratio of the secondarily sintered palladium - carbon catalyst to hydrogen peroxide is 1:15 - 20, and the stirring speed is 1000 - 2000 r / min; during the light - irradiation treatment, a photocatalytic xenon - lamp light source is used for irradiation, the light intensity is 200 - 220 W / cm 2 , the temperature is 40 - 60°C, and the light - irradiation treatment time is 3 - 5 h.

[0009] In Step 4, the speed of the first stirring is 2000 - 3000 r / min; the speed of the second stirring is 400 - 600 r / min; the standing time is 20 - 30 min, the standing temperature is 10 - 20°C, and the drying temperature is 80 - 100°C; the concentration of the preliminarily activated palladium - carbon catalyst in the palladium acetate solution is 40 - 80 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 100 - 200 g / L.

[0010] In Step 5, the sintering time is 1 - 2 h, and the sintering temperature is 285 - 290°C; the reducing agent solution is a hydrazine hydrate aqueous solution with a mass fraction of 15 - 20%; the reaction temperature is 20 - 40°C, and the reaction time is 2 - 3 h.

[0011] The beneficial effects of the present invention are as follows: The activation method of the present invention reduces the damage of activated carbon during the carbon deposition removal process, effectively improves the stability of the activated - carbon carrier. At the same time, the deposition of palladium acetate forms a secondary loading with the remaining carbon deposition as the carrier, covering the palladium element on the surface, achieving the restoration and improvement of activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an electron - microscope photograph of the deactivated palladium - carbon catalyst; Figure 2 It is an electron - microscope photograph of the palladium - carbon catalyst activated by the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below in combination with the specific embodiments and the drawings.

[0014] Activation method for deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1: Sinter the deactivated palladium-carbon catalyst for 2 - 4 h, and then purge with nitrogen for 2 - 3 h to obtain a preliminarily sintered palladium-carbon catalyst; The temperature for sintering treatment is 200 - 250 °C, and the temperature for nitrogen purging is 20 - 40 °C; Step 2: Put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment for 20 - 30 min, filter, and then perform secondary sintering for 2 - 4 h. After cooling, a secondarily sintered palladium-carbon catalyst is obtained; The volume ratio of ethanol in the ethanol-aqueous solution is 30 - 40%; The concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 500 - 800 g / L; The ultrasonic frequency for ultrasonic treatment is 80 - 100 kHz, and the temperature is 20 - 40 °C; The temperature for secondary sintering is 100 - 120 °C; natural cooling is used for cooling; The carbon deposition on the palladium-carbon catalyst belongs to the deposition during the reaction process. The pores are relatively small and in a wrapped form. The purpose of preliminary sintering is to burn in a relatively low-temperature environment, preferentially remove the easily removable carbon deposition on the surface, and the air permeability is relatively high, which can preferentially consume the carbon deposition between the activated carbon and the carbon deposition. Ultrasonic uses the method of high-frequency vibration to penetrate the liquid into the voids, and at the same time physically peel off the loosened carbon deposition after sintering. Further sintering after high-frequency vibration is to reduce the unstable carbon deposition and impurities on the surface; the activated carbon and the carbon deposition are extremely close, and the carbon deposition is coated on the outside of the activated carbon. Therefore, the method of multiple sintering can effectively control the sintering rate of the carbon deposition and reduce the influence on the activated carbon. Simply put, the first sintering is mainly to remove the carbon deposition. During this process, the whole palladium-carbon catalyst is wrapped by the carbon deposition and will not affect the activated carbon (sintering from the outside to the inside). The purpose of ultrasonic and secondary sintering is physical peeling and separation of unstable carbon deposition, tending to physical peeling. After secondary sintering, most of the carbon deposition is removed, and there will be a small amount of carbon deposition adhering, and this carbon deposition mainly directly contacts the activated carbon.

[0015] Step 3: Immerse the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then perform light treatment for 3 - 5 h to obtain a preliminarily activated palladium-carbon catalyst; The mass ratio of the secondarily sintered palladium-carbon catalyst to hydrogen peroxide is 1:15 - 20, and the hydrogen peroxide is saturated hydrogen peroxide; the stirring speed is 1000 - 2000 r / min; During light treatment, a photocatalytic xenon lamp source is used for irradiation, and the light intensity is 200 - 220 W / cm 2 and the temperature is 40 - 60 °C; Hydrogen peroxide contains peroxides that can decompose to form oxygen and water, and the peroxides have good oxidation activity and can oxidize palladium elements. At the same time, palladium elements themselves are highly dispersed materials, generally in the form of nanoscale particles, and the oxidation belongs to an in-situ oxidation system, which will bring nanoscale palladium oxide particles. Palladium oxide particles themselves are highly active photocatalytic materials that can promote the overall oxidation reaction. At the same time, the change in the particles of palladium oxide will drive the loosening of some unstable carbon deposits and their detachment (the change in the molecular structure of palladium oxide and palladium will affect the deposition of carbon deposits).

[0016] Step 4: Stir the preliminarily activated palladium-carbon catalyst for 20 - 30 minutes, filter it, soak it in a palladium acetate solution, stir evenly, let it stand for 20 - 30 minutes, and then dry it to obtain a coated palladium-carbon catalyst; The stirring speed for the first time is 2000 - 3000 r / min; the stirring speed for the second time is 400 - 600 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 40 - 80 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 100 - 200 g / L; The temperature for standing is 10 - 20 °C, and the temperature for drying is 80 - 100 °C; The activated carbon structure in the palladium-carbon catalyst remains basically unchanged. The secondary addition of palladium acetate is to supplement the palladium lost during the previous use process to ensure the activity of the activated catalyst.

[0017] Step 5: Subject the coated palladium-carbon catalyst to high-temperature sintering for 1 - 2 hours, then soak it in a reducing agent solution and react for 2 - 3 hours, and filter to obtain an activated palladium-carbon catalyst; The temperature for high-temperature sintering is 285 - 290 °C; the reducing agent solution uses a hydrazine hydrate aqueous solution with a mass fraction of 15 - 20%; the reaction temperature is 20 - 40 °C.

[0018] Example 1 The activation method of the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1: Subject the deactivated palladium-carbon catalyst to sintering treatment for 2 hours, and then purge it with nitrogen for 2 hours to obtain a preliminarily sintered palladium-carbon catalyst; The temperature for sintering treatment is 200 °C, and the temperature for purging with nitrogen is 20 °C; Step 2: Put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment for 20 minutes, filter it, and then perform secondary sintering for 2 hours. After cooling, obtain a secondarily sintered palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 30%; the concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 500 g / L; the ultrasonic frequency for ultrasonic treatment is 80 kHz, and the temperature is 20 °C; the temperature for secondary sintering is 100 °C; Step 3: Immerse the secondary calcined palladium-carbon catalyst in hydrogen peroxide and stir, then perform light treatment for 3 h to obtain a preliminarily activated palladium-carbon catalyst; The mass ratio of the secondary calcined palladium-carbon catalyst to hydrogen peroxide is 1:15, and the hydrogen peroxide is saturated hydrogen peroxide; the stirring speed is 1000 r / min; During the light treatment, it is irradiated with a photocatalytic xenon lamp light source, and the light intensity is 200 W / cm 2 , and the temperature is 40 °C; Step 4: Stir the preliminarily activated palladium-carbon catalyst for 20 min, filter it, then immerse it in the palladium acetate solution and stir evenly, let it stand for 20 min and then dry it to obtain a coated palladium-carbon catalyst; The speed of the first stirring is 2000 r / min; the speed of the second stirring is 400 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 40 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 100 g / L; The temperature for standing is 10 °C, and the temperature for drying is 80 °C; Step 5: Subject the coated palladium-carbon catalyst to high-temperature sintering for 1 h, then immerse it in the reducing agent solution and react for 2 h, and filter to obtain an activated palladium-carbon catalyst; The temperature for high-temperature sintering is 285 °C; the reducing agent solution uses a hydrazine hydrate aqueous solution with a mass fraction of 15%; the reaction temperature is 20 °C.

[0019] Example 2 The activation method of the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1: Subject the deactivated palladium-carbon catalyst to sintering treatment for 2.5 h, and then purge with nitrogen for 3 h to obtain a primary calcined palladium-carbon catalyst; The temperature for sintering treatment is 205 °C, and the temperature for purging with nitrogen is 22 °C; Step 2: Put the primary calcined palladium-carbon catalyst into an ethanol-aqueous solution and perform ultrasonic treatment for 20 min, filter it, and then perform secondary sintering for 2.5 h, and cool down to obtain a secondary calcined palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 32%; the concentration of the primary calcined palladium-carbon catalyst in the ethanol-aqueous solution is 580 g / L; The ultrasonic frequency for ultrasonic treatment is 80 kHz, and the temperature is 30 °C; the temperature for secondary sintering is 110 °C; Step 3: Immerse the secondary calcined palladium-carbon catalyst in hydrogen peroxide and stir, then perform light treatment for 4 h to obtain a preliminarily activated palladium-carbon catalyst; The mass ratio of the secondary calcined palladium-carbon catalyst to hydrogen peroxide is 1:18; the stirring speed is 1200 r / min; During the light treatment, it is irradiated with a photocatalytic xenon lamp light source, and the light intensity is 200 W / cm2 , the temperature is 50 °C; Step 4, stir the preliminarily activated palladium-carbon catalyst for 20 min, filter it and soak it in the palladium acetate solution, stir evenly, let it stand for 20 min and then dry it to obtain the coated palladium-carbon catalyst; The stirring speed for the first time is 2100 r / min; the stirring speed for the second time is 500 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 60 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 120 g / L; The temperature for standing is 15 °C, and the temperature for drying is 90 °C; Step 5, sinter the coated palladium-carbon catalyst at a high temperature for 2 h, then soak it in the reducing agent solution and react for 3 h, and filter to obtain the activated palladium-carbon catalyst; The temperature for high-temperature sintering is 285 °C; the reducing agent solution uses a hydrazine hydrate aqueous solution with a mass fraction of 15%; the reaction temperature is 40 °C.

[0020] Example 3 The activation method of the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1, sinter the deactivated palladium-carbon catalyst for 3.5 h, and then purge it with nitrogen for 3 h to obtain the initially sintered palladium-carbon catalyst; The temperature for sintering treatment is 240 °C, and the temperature for nitrogen purging is 30 °C; Step 2, put the initially sintered palladium-carbon catalyst into an ethanol-aqueous solution and perform ultrasonic treatment for 30 min, filter it and then perform secondary sintering for 4 h, and cool it to obtain the secondarily sintered palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 40%; the concentration of the initially sintered palladium-carbon catalyst in the ethanol-aqueous solution is 700 g / L; The ultrasonic frequency for ultrasonic treatment is 80 kHz, and the temperature is 25 °C; the temperature for secondary sintering is 100 °C; Step 3, soak the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then perform light treatment for 3 - 5 h to obtain the preliminarily activated palladium-carbon catalyst; The mass ratio of the secondarily sintered palladium-carbon catalyst to hydrogen peroxide is 1:20; the stirring speed is 1500 r / min; During the light treatment, it is irradiated with a photocatalytic xenon lamp light source, and the light intensity is 210 W / cm 2 , the temperature is 40 °C; Step 4, stir the preliminarily activated palladium-carbon catalyst for 30 min, filter it and soak it in the palladium acetate solution, stir evenly, let it stand for 30 min and then dry it to obtain the coated palladium-carbon catalyst; The stirring speed for the first time is 2800 r / min; the stirring speed for the second time is 450 r / min; The concentration of palladium acetate solution for the preliminarily activated palladium-carbon catalyst is 60 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 140 g / L; The temperature for standing is 20 °C, and the temperature for drying is 100 °C; Step 5, subject the coated palladium-carbon catalyst to high-temperature sintering for 2 h, then immerse it in a reducing agent solution for reaction for 3 h, and filter to obtain the activated palladium-carbon catalyst; The temperature for high-temperature sintering is 290 °C; the reducing agent solution is an aqueous hydrazine hydrate solution with a mass fraction of 15%; the reaction temperature is 20 °C.

[0021] Example 4 The activation method of the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1, subject the deactivated palladium-carbon catalyst to sintering treatment for 2 h, and then purge with nitrogen for 3 h to obtain the preliminarily sintered palladium-carbon catalyst; The temperature for sintering treatment is 225 °C, and the temperature for purging with nitrogen is 34 °C; Step 2, put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment for 20 min, filter and then conduct secondary sintering for 3.5 h, and cool down to obtain the secondarily sintered palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 30%; the concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 680 g / L; The ultrasonic frequency for ultrasonic treatment is 80 kHz, and the temperature is 20 °C; the temperature for secondary sintering is 118 °C; Step 3, immerse the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then conduct light treatment for 3 h to obtain the preliminarily activated palladium-carbon catalyst; The mass ratio of the secondarily sintered palladium-carbon catalyst to hydrogen peroxide is 1:15, and the hydrogen peroxide is saturated hydrogen peroxide; the stirring speed is 1800 r / min; During the light treatment, it is irradiated with a photocatalytic xenon lamp light source, and the light intensity is 200 W / cm 2 , and the temperature is 40 °C; Step 4, stir the preliminarily activated palladium-carbon catalyst for 30 min, filter and then immerse it in the palladium acetate solution and stir evenly, stand for 30 min and then dry to obtain the coated palladium-carbon catalyst; The speed of the first stirring is 2600 r / min; the speed of the second stirring is 570 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 56 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 150 g / L; The temperature for standing is 10 °C, and the temperature for drying is 80 °C; Step 5, subject the palladium-carbon catalyst with coating to high-temperature sintering for 1 h, then immerse it in a reducing agent solution for reaction for 2 h, and filter to obtain an activated palladium-carbon catalyst; The temperature of high-temperature sintering is 290 °C; the reducing agent solution is an aqueous hydrazine hydrate solution with a mass fraction of 20%; the reaction temperature is 40 °C.

[0022] Example 5 The method for activating the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1, subject the deactivated palladium-carbon catalyst to sintering treatment for 2 h, and then purge with nitrogen for 2 h to obtain a preliminarily sintered palladium-carbon catalyst; The temperature of sintering treatment is 215 °C, and the temperature of nitrogen purging is 20 °C; Step 2, put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment for 20 min, filter and then perform secondary sintering for 2 h, and cool down to obtain a secondarily sintered palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 30%; The concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 700 g / L; The ultrasonic frequency of ultrasonic treatment is 90 kHz, and the temperature is 30 °C; The temperature of secondary sintering is 120 °C; natural cooling is used for cooling down; Step 3, immerse the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then perform light treatment for 3 h to obtain a preliminarily activated palladium-carbon catalyst; The mass ratio of the secondarily sintered palladium-carbon catalyst to hydrogen peroxide is 1:15, and the hydrogen peroxide is saturated hydrogen peroxide; the stirring speed is 1600 r / min; During light treatment, a photocatalytic xenon lamp light source is used for irradiation, and the light intensity is 200 W / cm 2 , and the temperature is 40 °C; Step 4, stir the preliminarily activated palladium-carbon catalyst for 30 min, filter and then immerse it in a palladium acetate solution and stir evenly, let it stand for 20 min and then dry to obtain a palladium-carbon catalyst with coating; The speed of the first stirring is 2700 r / min; the speed of the second stirring is 500 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 70 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 125 g / L; The temperature of standing is 10 °C, and the temperature of drying is 80 °C; Step 5, subject the palladium-carbon catalyst with coating to high-temperature sintering for 1 - 2 h, then immerse it in a reducing agent solution for reaction for 2 - 3 h, and filter to obtain an activated palladium-carbon catalyst; The temperature of the high-temperature sintering is 285 °C; the reducing agent solution is an aqueous hydrazine hydrate solution with a mass fraction of 15%; the reaction temperature is 40 °C.

[0023] Example 6 The activation method of the deactivated palladium-carbon catalyst of the present invention is specifically implemented according to the following steps: Step 1, sinter the deactivated palladium-carbon catalyst for 4 h, and then purge with nitrogen for 3 h to obtain a preliminarily sintered palladium-carbon catalyst; The temperature of the sintering treatment is 250 °C, and the temperature of the nitrogen purge is 40 °C; Step 2, put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment for 30 min, filter and then perform secondary sintering for 4 h, and cool down to obtain a secondarily sintered palladium-carbon catalyst; The volume ratio of ethanol in the ethanol-aqueous solution is 40%; The concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 800 g / L; The ultrasonic frequency of the ultrasonic treatment is 100 kHz, and the temperature is 40 °C; The temperature of the secondary sintering is 120 °C; natural cooling is used for cooling; Step 3, soak the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then perform light treatment for 5 h to obtain a preliminarily activated palladium-carbon catalyst; The mass ratio of the secondarily sintered palladium-carbon catalyst to hydrogen peroxide is 1:20, and the hydrogen peroxide is saturated hydrogen peroxide; the stirring speed is 2000 r / min; During the light treatment, a photocatalytic xenon lamp light source is used for irradiation, and the light intensity is 220 W / cm 2 , and the temperature is 60 °C; Step 4, stir the preliminarily activated palladium-carbon catalyst for 30 min, filter and then soak it in a palladium acetate solution and stir evenly, let it stand for 30 min and then dry it to obtain a coated palladium-carbon catalyst; The speed of the first stirring is 3000 r / min; the speed of the second stirring is 600 r / min; The concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 80 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 200 g / L; The temperature of standing is 20 °C, and the temperature of drying is 100 °C; Step 5, perform high-temperature sintering on the coated palladium-carbon catalyst for 2 h, then soak it in a reducing agent solution and react for 3 h, filter to obtain an activated palladium-carbon catalyst; The temperature of the high-temperature sintering is 290 °C; the reducing agent solution is an aqueous hydrazine hydrate solution with a mass fraction of 20%; the reaction temperature is 40 °C.

[0024] Figure 1 is the electron microscope photograph of the deactivated palladium-carbon catalyst,Figure 2 The electron microscope photograph of the palladium-carbon catalyst after being activated by the method of the present invention. It can be seen from the figure that the deactivated palladium-carbon catalyst has relatively serious agglomeration phenomenon, which affects the use activity of the catalyst; after activation, the palladium-carbon catalyst particles are dispersed, the dispersion degree of the active component is high, and the boundary is clear.

Claims

1. A method for activating a deactivated palladium-carbon catalyst, characterized in that, The implementation is specifically carried out according to the following steps: Step 1: Sinter the deactivated palladium-carbon catalyst, and then purge it with nitrogen to obtain the preliminarily sintered palladium-carbon catalyst; Step 2: Put the preliminarily sintered palladium-carbon catalyst into an ethanol-aqueous solution for ultrasonic treatment, filter it, and then conduct secondary sintering. After cooling, obtain the secondarily sintered palladium-carbon catalyst; Step 3: Immerse the secondarily sintered palladium-carbon catalyst in hydrogen peroxide and stir, and then conduct light treatment to obtain the preliminarily activated palladium-carbon catalyst; Step 4: Stir the preliminarily activated palladium-carbon catalyst, filter it, immerse it in a palladium acetate solution and stir evenly, let it stand, and then dry it to obtain the coated palladium-carbon catalyst; Step 5: Sinter the coated palladium-carbon catalyst, then immerse it in a reducing agent solution for reaction, filter it to obtain the activated palladium-carbon catalyst.

2. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 1, the sintering treatment temperature is 200 - 250 °C, the sintering treatment time is 2 - 4 h, the nitrogen purging temperature is 20 - 40 °C; the nitrogen purging time is 2 - 3 h.

3. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 2, the ultrasonic frequency is 80 - 100 kHz, the ultrasonic temperature is 20 - 40 °C, and the ultrasonic time is 20 - 30 min.

4. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 2, the concentration of the preliminarily sintered palladium-carbon catalyst in the ethanol-aqueous solution is 500 - 800 g / L; the secondary sintering temperature is 100 - 120 °C; the secondary sintering time is 2 - 4 h.

5. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said step 3, the mass ratio of the second-burned palladium-carbon catalyst to hydrogen peroxide is 1:15 - 20, and the stirring speed is 1000 - 2000 r / min; during the light treatment, a photocatalytic xenon lamp light source is used for irradiation, the light intensity is 200 - 220 W / cm 2 , the temperature is 40 - 60 °C, and the light treatment time is 3 - 5 h.

6. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 4, the speed of the first stirring is 2000 - 3000 r / min; the speed of the second stirring is 400 - 600 r / min; the standing time is 20 - 30 min, the standing temperature is 10 - 20 °C, and the drying temperature is 80 - 100 °C.

7. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that In the said Step 4, the concentration of the preliminarily activated palladium-carbon catalyst in the palladium acetate solution is 40 - 80 g / L, and the palladium acetate solution is a palladium acetate ethanol solution with a concentration of 100 - 200 g / L.

8. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 5, the sintering time is 1 - 2 h, and the sintering temperature is 285 - 290 °C.

9. The activation method of the deactivated palladium-carbon catalyst according to claim 1, characterized in that, In the said Step 5, the reducing agent solution uses an aqueous hydrazine hydrate solution with a mass fraction of 15 - 20%; the reaction temperature is 20 - 40 °C, and the reaction time is 2 - 3 h.

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