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CN-121988410-A - Rare earth-based organic contaminated soil thermal desorption catalyst and preparation method and application thereof

CN121988410ACN 121988410 ACN121988410 ACN 121988410ACN-121988410-A

Abstract

The invention discloses a rare earth-based organic contaminated soil thermal desorption catalyst and a preparation method and application thereof, wherein the catalyst takes a composite oxide of cerium dioxide and manganese dioxide as an active component, ferroferric oxide as a promoter, and the mass percentage of the promoter is 3-6% based on the mass of the active component. The catalyst synthesized by the method has the advantages of good soil compatibility, high catalytic efficiency and the like, and can achieve the aim of repairing organic pollutant soil with low energy consumption.

Inventors

  • XU HAITAO
  • ZHOU CHANGCHENG
  • LI MINGBO
  • ZHAN ZHIBO
  • JIN QIJIE
  • SHI XUETING
  • LU JUN
  • YAN WEI
  • ZHOU RANRAN
  • Xu Mutao
  • CHEN LIGUO
  • SONG JING

Assignees

  • 南京工业大学
  • 南京杰科丰环保技术装备研究院有限公司

Dates

Publication Date
20260508
Application Date
20260324

Claims (10)

  1. 1. A rare earth-based organic contaminated soil thermal desorption catalyst is characterized in that the catalyst is prepared by adopting a combined method of low-temperature spray drying, ion-assisted hydrothermal-chemical vapor deposition and microwave calcination activation by taking a composite oxide of cerium oxide and manganese dioxide as an active component and ferroferric oxide as a promoter, wherein the micro morphology is a nano spherical synaptic structure, the mass percentage of the promoter is 3-6% based on the mass of the active component, and the mass ratio of the cerium oxide to the manganese dioxide in the active component is 1 (0.5-2).
  2. 2. A process for preparing a catalyst according to claim 1, wherein the process comprises the steps of: (1) Precursor skeleton prepared by low-temperature spray drying Weighing cerium salt, manganese salt, polyether F127, deionized water and absolute ethyl alcohol, mixing to form a precursor mixed solution, then conveying the precursor mixed solution to a two-fluid nozzle of a spray dryer through a peristaltic pump, and performing low-temperature spray drying to form precursor skeleton powder; (2) Ion-assisted hydrothermally structured synapse structures Weighing the precursor skeleton powder prepared in the step (1), ferric salt, urea and 1-butyl-3-methylimidazole tetrafluoroborate, mixing to form mixed slurry, performing ultrasonic treatment, placing the mixed slurry in a hydrothermal reaction kettle for hydrothermal reaction, performing centrifugal separation after the reaction is finished, cleaning the mixed slurry with deionized water and absolute ethyl alcohol, and finally performing vacuum drying to obtain composite material powder; (3) Construction of nanosynapse structures by chemical vapor deposition Placing the composite material powder prepared in the step (2) into a quartz boat, then placing the quartz boat into a sample stage of a chemical vapor deposition device, weighing ferric salt and benzene, mixing to form a mixed solution, placing the mixed solution into an oil bath, taking a mixed gas of argon and oxygen as a carrier gas, introducing the carrier gas into a plasma spray head after passing through the mixed solution, and performing chemical vapor deposition to obtain a composite material sample after deposition is finished; (4) Preparation of catalyst by microwave calcination and activation And (3) placing the composite material sample obtained in the step (3) in a microwave muffle furnace, and heating and roasting in an air atmosphere to obtain the catalyst.
  3. 3. The preparation method of the aqueous solution of the cerium nitrate or the cerium chloride, which is characterized in that the cerium salt in the step (1) is cerium nitrate hexahydrate or cerium chloride, the manganese salt is manganese nitrate hexahydrate or manganese chloride, and the mass ratio of cerium salt, polyether F127, deionized water and absolute ethyl alcohol is 1 (0.3-0.6): 5-10): 1-3.
  4. 4. The method of claim 2, wherein the rate of delivery by a peristaltic pump in step (1) is 3-6 mL/min, the inlet temperature of the two-fluid nozzle in the low-temperature spray drying process is 200-240 ℃, the outlet temperature is 110-130 ℃, and the atomized nitrogen pressure is 0.3-0.5 MPa.
  5. 5. The preparation method of the iron salt according to claim 2, wherein the iron salt in the step (2) is ferric nitrate nonahydrate or ferric chloride hexahydrate, the mass ratio of the precursor skeleton powder to the urea to the 1-butyl-3-methylimidazole tetrafluoroborate is 1 (0.1-0.2): (10-15), and the molar ratio of the iron salt in the step (2) to the iron salt in the step (3) is 1 (0.5-2).
  6. 6. The preparation method of the vacuum drying agent according to claim 2, wherein the power of the ultrasonic treatment in the step (2) is 100-150W, the time of the ultrasonic treatment is 5-10 min, the temperature of the hydrothermal reaction is 140-160 ℃, the time of the hydrothermal reaction is 6-12 h, the temperature of the vacuum drying is 60-80 ℃, and the time of the vacuum drying is 12-24 h.
  7. 7. The preparation method of the high-purity iron oxide film according to claim 2, wherein the ferric salt in the step (3) is ferric acetylacetonate, the mass ratio of the ferric salt to benzene is 1 (80-120), the temperature of the oil bath is 70-90 ℃, the argon gas introducing rate is 1-2L/min, the oxygen gas introducing rate is 100-200 mL/min, the power of plasma in the chemical vapor deposition process is 150-200W, and the scanning rate of a plasma nozzle is 5-10 mm/s.
  8. 8. The method of claim 2, wherein the baking temperature in the step (4) is 450-550 ℃ and the baking time is 2-4 hours.
  9. 9. The use of the catalyst of claim 1 for the catalytic removal of organic pollutants in the field of soil remediation.
  10. 10. Use according to claim 9, characterized in that the organic contaminant is chlorobenzene.

Description

Rare earth-based organic contaminated soil thermal desorption catalyst and preparation method and application thereof Technical Field The invention relates to a rare earth-based organic contaminated soil thermal desorption catalyst and a preparation method and application thereof, belonging to the field of soil pollution remediation. Background The historic legacy sites of the industries of coking, chemical industry, petrochemical industry, pesticide, printing and dyeing and the like are overlapped with newly-added polluted plots, so that high-risk organic matters such as polycyclic aromatic hydrocarbon, chlorinated organic matters, petroleum hydrocarbon, persistent organic pollutants and the like are accumulated in soil for a long time, and the soil has high concentration, strong toxicity and stable molecular structure and can take effect only by depending on bioremediation for decades. Although the traditional thermal desorption can volatilize and separate pollutants from soil within a few hours, the traditional device mostly depends on high temperature of more than 800 ℃, and has high energy consumption and great difficulty in controlling secondary pollutants in tail gas. The catalyst-assisted low-temperature desorption technology has important significance in the field of organic matter polluted soil remediation by virtue of the advantage of being capable of realizing efficient pollutant cracking in the range of 250-550 ℃. The development of the catalyst is the key of the catalytic removal technology. In recent years, researchers have made remarkable progress in the synthesis, modification and application of soil remediation catalysts. Noble metal catalysts such as platinum, palladium, rhodium, etc. have been widely studied, and they exhibit excellent catalytic activity in oxidation and reduction reactions of organic pollutants. Although noble metal catalysts are highly active, they are costly and limit large-scale applications. The metal oxide catalysts such as titanium dioxide (TiO 2) and manganese dioxide (MnO 2) have good effects in photocatalytic degradation and oxidation reaction of soil organic pollutants, and particularly have strong photocatalytic activity under ultraviolet light irradiation. In addition, the nano material has great potential in soil pollution treatment due to the high specific surface area and unique catalytic performance. The nano catalyst not only improves the reaction efficiency, but also enhances the adsorption and degradation capability of pollutants. Therefore, the development of the nano soil remediation catalyst with low cost, no toxicity and high efficiency, especially when treating complex and various organic pollutants, has great significance in improving the selectivity and durability of the catalyst. Disclosure of Invention The invention aims at solving the current situation and problems of the catalytic removal of the existing soil organic pollutants, and provides a rare earth-based organic polluted soil thermal desorption catalyst, a preparation method and application thereof. A rare earth-based organic contaminated soil thermal desorption catalyst is characterized in that the catalyst is prepared by adopting a combined method of low-temperature spray drying, ion-assisted hydrothermal-chemical vapor deposition and microwave calcination activation by taking a composite oxide of cerium oxide and manganese dioxide as an active component and ferroferric oxide as a promoter, wherein the micro morphology is a nano spherical synaptic structure, the mass percentage of the promoter is 3-6% based on the mass of the active component, and the mass ratio of the cerium oxide to the manganese dioxide in the active component is 1 (0.5-2). The preparation method of the catalyst comprises the following steps: (1) Precursor skeleton prepared by low-temperature spray drying Weighing cerium salt, manganese salt, polyether F127, deionized water and absolute ethyl alcohol, mixing to form a precursor mixed solution, then conveying the precursor mixed solution to a two-fluid nozzle of a spray dryer through a peristaltic pump, and performing low-temperature spray drying to form precursor skeleton powder; (2) Ion-assisted hydrothermally structured synapse structures Weighing the precursor skeleton powder prepared in the step (1), ferric salt, urea and 1-butyl-3-methylimidazole tetrafluoroborate, mixing to form mixed slurry, performing ultrasonic treatment, placing the mixed slurry in a hydrothermal reaction kettle for hydrothermal reaction, performing centrifugal separation after the reaction is finished, cleaning the mixed slurry with deionized water and absolute ethyl alcohol, and finally performing vacuum drying to obtain composite material powder; (3) Construction of nanosynapse structures by chemical vapor deposition Placing the composite material powder prepared in the step (2) into a quartz boat, then placing the quartz boat into a sample stage of a chemical vapor deposition device