CN107377008A - One kind carries palladium fiber base catalyst and its production and use - Google Patents

Abstract

The invention provides a palladium-loaded fiber-based catalyst, a preparation method and application thereof. In the palladium-loaded fiber-based catalyst of the present invention, the carrier of the catalyst is fiber, the active component is palladium loaded on the carrier, and the mass of the palladium is 0.05 to 2% based on the mass of the carrier as 100%. %. In the present invention, the fiber is used as a carrier, and the advantages of high porosity and high mass transfer efficiency of the fiber material are utilized, and the active precious metal palladium is loaded on the fiber material to prepare a palladium-loaded fiber-based catalyst for burning and purifying benzene, which can efficiently degrade the highly toxic volatile organic compound benzene. The catalyst has the advantages of high porosity, high mass transfer efficiency, easy molding, and low reaction temperature for benzene degradation. Purification treatment.

Description

A kind of palladium-loaded fiber-based catalyst and its preparation method and application

technical field

The invention belongs to the technical field of catalysts, and relates to a palladium-loaded fiber-based catalyst and its preparation method and application, in particular to a palladium-loaded fiber-based catalyst for catalytic combustion of volatile organic compounds and a preparation method thereof, in particular to a Palladium-loaded fiber-based catalyst for catalytic combustion of benzene and its preparation method.

Background technique

As the intensity of human industrial activities increases, a large amount of volatile organic compounds (Volatile Organic Compounds, VOCs for short) are discharged into the atmosphere, causing environmental pollution through a series of chemical reactions. For example, some highly active VOCs can react photochemically with another atmospheric pollutant, nitrogen oxides (NO _x ), causing an increase in the concentration of surface ozone and forming photochemical smog pollution; some VOCs with low vapor pressure can also nucleate through complex processes It grows up to form secondary organic aerosol, and secondary organic aerosol is an important part of fine particulate matter PM2.5. It can be seen that VOCs are important precursors for the formation of photochemical pollution and atmospheric haze. In addition, VOCs themselves can pose a huge threat to human health. For example, common VOCs such as formaldehyde, benzene, toluene, etc. have carcinogenic and teratogenic hazards. Therefore, to remove photochemical smog, reduce particle pollution, improve urban air quality, and protect people's health, it is imperative to control and remove VOCs emissions.

VOCs come from a wide range of sources, mainly including petroleum, chemical industry, medicine, packaging, printing, coating, etc. Taking the coating industry as an example, its VOCs emissions are nearly 7 million tons per year, accounting for about 1/3 of the total VOCs emissions . In the field of VOCs elimination and purification in the coating industry, major western developed countries and Japan started earlier. In 1955, the United States promulgated the "Air Pollution Control Act", which made detailed regulations on the types and total amount of air pollutant emissions. In 1966, special regulations were formulated specifically for VOCs emissions in the coating industry, namely "Regulation 66". Driven by legal constraints and corporate interests, different technologies for eliminating VOCs have been developed and used.

At present, my country attaches great importance to the pollution of VOCs, and requires that by 2020, the whole process of VOCs emission reduction from raw materials to products, from production to consumption will be basically realized. Therefore, VOCs emission reduction technologies have been extensively researched and explored.

Benzene is one of the most toxic volatile organic compounds. The "Code for Indoor Environmental Pollution Control of Civil Construction Engineering" GB50325-2001 strictly limits its concentration, requiring its concentration to be less than 0.09mg/m ³ . Therefore, it is very necessary to treat the tail gas containing benzene from the emission source. Catalytic combustion of benzene is a more efficient control technology at present, but the traditional powder catalysts have disadvantages such as difficult molding and large mass transfer resistance.

Contents of the invention

In view of the deficiencies in the prior art, one of the objectives of the present invention is to provide a palladium-loaded fiber-based catalyst with high catalytic activity, high porosity, high mass transfer efficiency, easy molding, and low reaction temperature for benzene degradation.

For reaching this purpose, the present invention adopts following technical scheme:

A palladium-loaded fiber-based catalyst, the carrier of the catalyst is fiber, the active component is palladium loaded on the carrier, and the mass of the palladium is 0.05-2% based on the mass of the carrier as 100% .

In the present invention, the fiber is used as a carrier, and the advantages of high porosity and high mass transfer efficiency of the fiber material are utilized, and the active precious metal palladium is loaded on the fiber material to prepare a palladium-loaded fiber-based catalyst for burning and purifying benzene, which can efficiently degrade the highly toxic volatile organic compound benzene. The catalyst has the advantages of high porosity, high mass transfer efficiency, easy molding, and low reaction temperature for benzene degradation, and has a good application prospect.

The fiber described in the present invention is one or a mixture of at least two of ceramic fibers, glass fibers, metal fibers, and activated carbon fibers; a typical but non-limiting mixture of the mixture is a mixture of two fibers, such as ceramic fibers, glass A mixture of fibers, a mixture of ceramic fibers and metal fibers, a mixture of ceramic fibers and activated carbon fibers, a mixture of glass fibers and metal fibers, a mixture of glass fibers and activated carbon fibers, a mixture of metal fibers and activated carbon fibers; the mixture can be three A mixture of fibers, such as a mixture of ceramic fibers, glass fibers, metal fibers, a mixture of ceramic fibers, glass fibers, activated carbon fibers, a mixture of glass fibers, metal fibers, activated carbon fibers; the mixture can be a mixture of four fibers, For example, a mixture of ceramic fibers, glass fibers, metal fibers, activated carbon fibers. Preferably, the fibers are a mixture of glass fibers and ceramic fibers, and the mass ratio of the glass fibers to the ceramic fibers is (7-9):(1-3), such as 7:3, 8:2, 9 :1, preferably 8:2.

In the present invention, based on the mass of the carrier as 100%, the mass of the palladium is 0.05-2%, for example, the mass of the palladium is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 1%. , 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, preferably, based on the mass of the carrier being 100%, the mass of the palladium 1%.

The second object of the present invention is to provide a method for preparing the palladium-supported fiber-based catalyst as described above. The preparation method of the catalyst is simple, the catalyst activity is excellent, and it has good application potential. The preparation method includes the following steps :

1) pickling the carrier fiber;

2) impregnating the carrier fiber after pickling in step 1) in a solution containing palladium, then evaporating and drying;

3) roasting the dried product in step 2);

4) The product after the roasting treatment in step 3) is subjected to high-temperature reduction and retreatment to obtain a palladium-supported fiber-based catalyst.

The surface of the carrier fiber is relatively smooth. The present invention makes the surface of the fiber form unsaturated sites and other surface defects after pickling by pickling the carrier fiber. These unsaturated sites will bind more precious metal palladium, so that the loaded palladium will As for the agglomeration together to form large particles, the palladium is more uniformly loaded on the support fibers, thereby improving the activity of the catalyst. In the step 1) of the present invention, the pickling process includes immersing the carrier fiber in acid, and suctioning and filtering the rinsing liquid drop by drop in a vacuum drip filter bottle.

Preferably, the mass percentage of the acid is 10-60%, such as 10%, 20%, 30%, 40%, 50%, 60%, preferably 50%.

Preferably, the acid is sulfuric acid or nitric acid, preferably sulfuric acid.

Preferably, the solid-to-liquid ratio of the carrier fiber to the acid is 1/100 to 1/10 g/mL, for example, the solid-to-liquid ratio of the carrier fiber to the acid is 1/100, 1/90, 1/10 80, 1/70, 1/60, 1/50, 1/40, 1/30, 1/20, 1/10, preferably 1/50 g/mL.

Preferably, the rinsing time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, preferably 30 min, and the rinsing times are 1-3 times.

In step 1), the acid-washed fiber is rinsed with deionized water, and the pH value of the rinsed deionized water is neutral.

Preferably, after the deionized water is rinsed, a drying step is also included;

Preferably, the drying is carried out in an oven, the drying temperature is 100-150°C, for example, the drying temperature is 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, preferably 120°C ℃.

Preferably, the drying time is 5-24 hours, such as 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, preferably 12 hours.

In step 2), the palladium-containing solution is one of palladium nitrate dihydrate solution, palladium chloride solution and palladium acetate solution.

Preferably, the impregnation is ultrasonic-assisted impregnation, and the specific process of the ultrasonic-assisted impregnation is: placing the pickled carrier fiber in a palladium-containing solution to obtain a solid-liquid system, and placing the solid-liquid system in an ultrasonic pool Perform ultrasonic-assisted impregnation, the temperature of the ultrasonic-assisted impregnation is room temperature, preferably 23-27°C, such as 23°C, 24°C, 25°C, 26°C, 27°C; the ultrasonic frequency of the ultrasonic-assisted impregnation is 40-27°C. 50kHz, for example, the frequency of ultrasound is 40kHz, 41kHz, 42kHz, 43kHz, 44kHz, 45kHz, 46kHz, 47kHz, 48kHz, 49kHz, 50kHz, preferably 44kHz, and the time of ultrasonic-assisted impregnation is 10 to 60min, such as 10min, 20min, 30min, 40min, 50min, 60min, preferably 30min.

In step 2), the evaporation treatment is carried out in a rotary evaporating flask, and the rotation frequency of the rotary evaporation is 20 to 200r/min, for example, the rotation frequency is 20r/min, 30r/min, 40r/min, 50r/min. min, 60r/min, 70r/min, 80r/min, 90r/min, 100r/min, 110r/min, 120r/min, 130r/min, 140r/min, 150r/min, 160r/min, 170r/min, 180r/min, 190r/min, 200r/min, preferably 60r/min, the temperature of the rotary evaporation is 50-70°C, for example, the temperature of the rotary evaporation is 50°C, 51°C, 52°C, 53°C, 54°C , 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, preferably is 60°C.

Preferably, in step 2), the drying treatment is carried out in an oven, and the drying temperature is 80-120°C, for example, the drying temperature is 80°C, 90°C, 100°C, 110°C, 120°C, preferably 100°C, the drying time is 10-15h, for example, the drying time is 10h, 11h, 12h, 13h, 14h, 15h, preferably 12h.

In step 3), the temperature of the calcination treatment is 400-600°C, for example, the calcination temperature is 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, preferably 550 °C; the roasting time is 2 to 5 hours, For example, the roasting time is 2h, 3h, 4h, 5h, preferably 3h; the heating rate of the roasting is 2-10°C/min, for example, the heating rate is 2°C/min, 3°C/min, 4°C/min, 5°C. °C/min, 6°C/min, 7°C/min, 8°C/min, 9°C/min, 10°C/min.

In step 4), the high-temperature reduction retreatment process is: put the roasted product in step 3) into an atmosphere furnace for temperature-rising reduction treatment.

Preferably, the atmosphere in the atmosphere furnace is a reducing atmosphere, and nitrogen is used as a balance gas. Preferably, the reducing atmosphere is hydrogen, and the volume ratio of the hydrogen is 1 to 100%, for example, the volume ratio of hydrogen is 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, preferably 5%.

Preferably, the heating rate of the heating reduction is 2-10°C/min, for example, the heating rate is 2°C/min, 3°C/min, 4°C/min, 5°C/min, 6°C/min, 7°C/min min, 8°C/min, 9°C/min, 10°C/min, preferably 5°C/min; the temperature after the heating is 200-400°C, for example, the temperature after the heating is 200°C, 210°C, 220°C , 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C °C, 400 °C, preferably 300 °C; preferably, the time for the high-temperature reduction retreatment is 2-5 h, for example, the roasting time is 2 h, 3 h, 4 h, 5 h, preferably 2 h. The reduced catalyst can be directly used for the catalytic combustion of benzene, a volatile organic compound.

The third object of the present invention is to provide a use of a palladium-loaded fiber-based catalyst, which is used for catalytic combustion of volatile organic compound benzene.

The palladium-loaded fiber-based catalyst prepared in the present invention is stacked in filaments, easy to form and process, and is cotton-like after filling. Compared with powdery and granular catalysts, it has good air permeability, is easy to fill, and has no secondary pollution such as dust, and The catalyst has high efficiency and is widely used in the purification treatment of benzene contained in the waste gas emitted by stationary sources such as smelters, oil refineries, and chemical plants. After catalytic combustion, the highly toxic pollutant benzene can be completely decomposed into non-toxic and harmless carbon dioxide and water.

Compared with prior art, the beneficial effect of the present invention is:

(1) The palladium-loaded fiber-based catalyst of the present invention is stacked in a filamentary shape, has good air permeability, is easy to form and handle, and has no secondary pollution such as dust.

(2) The preparation method of the palladium-loaded fiber-based catalyst of the present invention is simple and easy, and the prepared palladium-loaded fiber-based catalyst is widely applicable to the purification treatment of benzene in exhaust gases discharged from stationary sources such as smelters, oil refineries, and chemical plants. Catalytic combustion of highly toxic pollutant benzene can be completely decomposed into non-toxic and harmless carbon dioxide and water.

(3) When the palladium-loaded fiber-based catalyst of the present invention is used for the catalytic combustion of volatile organic compound benzene, it has the advantages of high porosity, high mass transfer efficiency, easy molding, low reaction temperature for degrading benzene, and high catalyst efficiency. The space velocity is 90L/(g·h), the conversion rate of benzene can reach more than 95% when the reaction temperature is 250°C.

Description of drawings

1 is a schematic diagram of the benzene purification curve and the carbon dioxide yield curve when the catalyst prepared in Example 1 of the present invention is used for the catalytic combustion of volatile organic compound benzene;

2 is a schematic diagram of the benzene purification curve and the carbon dioxide yield curve when the catalyst prepared in Example 2 of the present invention is used for the catalytic combustion of volatile organic compound benzene;

3 is a schematic diagram of the benzene purification curve and the carbon dioxide yield curve when the catalyst prepared in Example 3 of the present invention is used for the catalytic combustion of volatile organic compound benzene;

4 is a schematic diagram of the benzene purification curve and the carbon dioxide yield curve when the catalyst prepared in Example 4 of the present invention is used for the catalytic combustion of volatile organic compound benzene;

Fig. 5 is the comparison chart of the conversion rate of benzene when the catalyst prepared by the embodiments of the present invention 1-6 is used for the catalytic combustion of volatile organic compound benzene;

Fig. 6 is the comparison chart of the conversion rate of benzene when the catalysts prepared by the embodiments of the present invention 3, 7, and 8 are used for the catalytic combustion of volatile organic compound benzene;

Fig. 7 is the SEM figure of the catalyst that the embodiment of the present invention 3 makes;

Fig. 8 is the SEM figure of the catalyst that the embodiment of the present invention 4 makes;

Fig. 9 is a N ₂ adsorption characterization diagram of the catalyst prepared in Example 8 of the present invention.

detailed description

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings 1-9 and through specific embodiments.

Example 1

A. Weigh 10g of ceramic fiber, (Fisher Chemical Triton Kaowool ceramic fiber.Code: T/3740/48) once with 500ml of deionized water, filter and rinse repeatedly through Buchner funnel, rinse for about 30 minutes once, and drain the sample Standby; weigh 0.25 g of palladium nitrate dihydrate, put it into 100 ml of deionized water, and stir to mix. The above ceramic fiber was added to 100ml of the solution. Then put it into the ultrasonic cleaning tank for ultrasonic assisted impregnation. Ultrasonic frequency 44KHz, impregnation 1h. The above solid-liquid system was transferred into a rotary evaporating flask, and the temperature was gradually raised from room temperature to 60°C to evaporate the solvent. Afterwards, put the impregnated product into an oven, and continue drying at 100° C. for 12 hours. Then take it out, lower it to room temperature, put it into a muffle furnace for roasting, and heat up at a rate of 5°C per minute to 500°C for 3 hours. Then cool down naturally and set aside.

B. The composition of the reaction mixture gas is: benzene [C ₆ H ₆ ]=1500ppm, [O ₂ ]=20%, N ₂ is used as the balance gas, the total gas flow rate is 300mL/min, and the space velocity is 90L/(g·h ), the reaction temperature is 150-400°C. The concentration of gases such as benzene, carbon dioxide, and oxygen was measured by gas chromatography (Agilent-7980B, FID and TCD);

C. The amount of the above-mentioned catalyst is 0.2g, and before the reaction evaluation, it needs to be treated with _H2 reduction. The conditions are: H ₂ =5%, N ₂ as the balance gas, the total gas flow rate is 400mL/min, the heating rate is 10°C per minute, the constant temperature is maintained at 300°C for 2 hours, and then the temperature rises to evaluate after cooling down to room temperature; the benzene purification curve and The carbon dioxide yield curve is shown in Fig. 1.

Example 2

The weighing matrix is: glass fiber 10g, (ACROS Organic Glass wool, Code: 386062500), and other operating parameters are as in Example 1 above. The obtained benzene purification curve and carbon dioxide yield curve are shown in Fig. 2 .

Example 3

Weigh 10g of ceramic fiber, configure 50(wet)% H ₂ SO ₄ solution, use 500ml of deionized water once, filter and wash repeatedly through Buchner funnel, rinse for about 30 minutes once, and wash with deionized water until neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1, and the benzene purification curve and carbon dioxide yield curve were obtained as shown in Figure 3. The morphology of the catalyst prepared in this example was scanned by an electron microscope, and the SEM image is shown in FIG. 7 .

Example 4

Weigh 10g of glass fiber, configure 50(wet)% H ₂ SO ₄ solution, use 500ml of deionized water once, filter through Buchner funnel repeatedly, rinse for about 30 minutes once, and wash with deionized water until neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1. The obtained benzene purification curve and carbon dioxide yield curve are shown in Figure 4. The morphology of the catalyst prepared in this example was scanned by an electron microscope, and the SEM image is shown in FIG. 8 .

Example 5

Weigh 10g of glass fiber, configure 50(wet)% HNO ₃ solution, use 500ml of deionized water once, filter and rinse repeatedly through Buchner funnel, rinse for about 30 minutes once, and wash with deionized water until neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1, and the evaluation results were shown in Figure 5.

Example 6

Weigh 10g of ceramic fiber, configure 50(wet)% HNO ₃ solution, use 500ml deionized water once, filter and rinse repeatedly through Buchner funnel, rinse once for about 30 minutes, and wash with deionized water until neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1, and the evaluation results were shown in Figure 6.

Example 7

Weigh 7g of ceramic fiber and 3g of glass fiber, configure 50(wet)% H ₂ SO ₄ solution, use 500ml of deionized water at a time, filter and rinse repeatedly through a Buchner funnel, rinse for about 30 minutes once, and rinse with deionized water until neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1, and the evaluation results were shown in Figure 6.

Example 8

Weigh ceramic fiber 8g plus glass fiber 2g, configure 50(wet)% H ₂ SO ₄ solution (source of product), once use 500ml deionized water, and repeatedly rinse by Buchner funnel suction filtration, once rinse for about 30 minutes, use Deionized wash to neutral. The sample was drained for later use; other preparation and evaluation methods were the same as in Example 1, and the evaluation results were shown in Figure 6. The specific surface area of the catalyst prepared in this example was tested, and the experimental results were shown in Figure 9.

In summary, as shown in Figure 5, compared with the deionized water rinsing in Example 1, the pickling in Example 3 and Example 4 has greatly improved the activity of the catalyst made of ceramic fibers or glass fibers . Compared with the nitric acid leaching in Example 5 and Example 6, and the sulfuric acid rinsing in Example 3 and Example 4, it can be seen that sulfuric acid rinsing has the best activity improvement for catalysts made of ceramic fibers or glass fibers. Compared with the glass fiber of Example 4, the activity of the ceramic fiber of Example 3 is better than that of glass fiber, but the activity of the catalyst prepared by mixing the two fibers of Example 7 and Example 8 is the best, as shown in Figure 6 .

It can be seen from Figures 7 and 8 that the carrier fibers are arranged in a rod shape, and the noble metal palladium is evenly loaded on the surface of the carrier fibers.

It can be seen from Figure 9 that the specific surface area of the catalyst prepared in Example 8 has been greatly improved, which is 87.57 m ² /g, compared to the specific surface area of ceramic fibers or glass fibers of 2-3 m ² /g , the increase of the specific surface area is beneficial to the activity of the catalyst.

The above examples are only used to illustrate the detailed methods of the present invention, and the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention can only be implemented depending on the above detailed methods. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. a palladium-loaded fiber-based catalyst is characterized in that the carrier of the catalyst is a fiber, and the active component is palladium loaded on the carrier, and the mass of the carrier is 100% in terms of the palladium. The mass is 0.05 to 2%. 2. palladium-loaded fiber-based catalyst according to claim 1, is characterized in that, described fiber is the mixture of one or at least two in ceramic fiber, glass fiber, metal fiber, active carbon fiber; Preferably, the fibers are a mixture of glass fibers and ceramic fibers, and the mass ratio of the glass fibers to the ceramic fibers is (7-9):(1-3), preferably 8:2; Preferably, the mass of the palladium is 1% based on 100% of the mass of the carrier. 3. a preparation method of palladium-loaded fiber-based catalyst as claimed in claim 1 or 2, is characterized in that, described preparation method comprises the steps: 1) pickling the carrier fiber; 2) impregnating the carrier fiber after pickling in step 1) in a solution containing palladium, then evaporating and drying; 3) roasting the dried product in step 2); 4) The product after the roasting treatment in step 3) is subjected to high-temperature reduction and retreatment to obtain a palladium-supported fiber-based catalyst. 4. preparation method according to claim 3, is characterized in that, in step 1), the process of described pickling is, the carrier fiber is soaked in the acid, in the vacuum trickling filter bottle, suck and filter the rinsing liquid drop by drop ; Preferably, the mass percentage of the acid is 10-60%, preferably 50%; Preferably, the acid is sulfuric acid or nitric acid, preferably sulfuric acid; Preferably, the solid-to-liquid ratio of the carrier fiber to the acid is 1/100-1/10 g/mL, preferably 1/50 g/mL; Preferably, the rinsing time is 20-40 min, preferably 30 min, and the rinsing times are 1-3 times. 5. according to the described preparation method of claim 3 or 4, it is characterized in that, in step 1), the fiber after described pickling is carried out deionized water rinse, and the pH value after described deionized water rinse is neutral ; Preferably, after the deionized water is rinsed, a drying step is also included; Preferably, the drying is carried out in an oven, and the drying temperature is 100-150°C, preferably 120°C; Preferably, the drying time is 5-24 hours, preferably 12 hours. 6. according to the described preparation method of one of claim 3-5, it is characterized in that, in step 2), described palladium-containing solution is the one in dihydrate palladium nitrate solution, palladium chloride solution, palladium acetate solution; Preferably, the impregnation is ultrasonic-assisted impregnation, and the specific process of the ultrasonic-assisted impregnation is: placing the pickled carrier fiber in a palladium-containing solution to obtain a solid-liquid system, and placing the solid-liquid system in an ultrasonic pool Carry out ultrasonic assisted impregnation, the temperature of described ultrasonic assisted impregnation is 23～27 ℃; The ultrasonic frequency of described ultrasonic assisted impregnation is 40～50kHz, preferably 44kHz; The time of described ultrasonic assisted impregnation is 10～60min, preferably 30min. 7. The preparation method according to any one of claims 3-6, characterized in that, in step 2), the evaporation treatment is carried out in a rotary evaporation flask, and the rotation frequency of the rotary evaporation is 20-200r/ min, preferably 60r/min; the temperature of the rotary evaporation is 50-70°C, preferably 60°C; Preferably, in step 2), the drying process is carried out in an oven, the drying temperature is 80-120°C, preferably 100°C; the drying time is 10-15h, preferably 12h. 8. The preparation method according to any one of claims 3-7, characterized in that, in step 3), the temperature of the roasting treatment is 400-600° C., preferably 550° C.; the roasting time is 2-600° C. 5h, preferably 3h; the heating rate of the calcination is 2-10°C/min. 9. The preparation method according to any one of claims 3-8, characterized in that, in step 4), the process of the high-temperature reduction retreatment is: putting the product roasted in step 3) into an atmosphere furnace Heating reduction treatment; Preferably, the atmosphere in the atmosphere furnace is hydrogen, and the volume ratio of the hydrogen is 1-100%, preferably 5%; Preferably, the heating rate of the heating reduction is 2-10°C/min, preferably 5°C/min, and the temperature after the heating is 200-400°C, preferably 300°C; preferably, the high-temperature reduction is The treatment time is 2 to 5 hours, preferably 2 hours. 10. A use of the palladium-loaded fiber-based catalyst as claimed in claim 1 or 2, characterized in that, the palladium-loaded fiber-based catalyst is used for catalytic combustion of volatile organic compound benzene.