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CN-122006817-A - Nitrogen-containing organic waste gas treatment catalyst and preparation method thereof

CN122006817ACN 122006817 ACN122006817 ACN 122006817ACN-122006817-A

Abstract

The invention relates to the technical field of nitrogen-containing organic waste gas treatment, and discloses a nitrogen-containing organic waste gas treatment catalyst and a preparation method thereof, wherein the water-resistant catalyst suitable for normal-temperature high-humidity environment comprises a micron-sized silicon dioxide carrier; the organic-inorganic hybrid crosslinking network is coated on the surface of the carrier, the crosslinking network is formed by covalent crosslinking of aldehyde group-containing polyhedral oligomeric polysiloxane and amino group-containing polyhedral oligomeric polysiloxane, the crosslinking network contains free carbon-carbon double bonds, an active component anchored in the crosslinking network, the active component is Cu-Pd bimetallic oxide modified by mercapto, and a long-chain alkyl hydrophobic layer grafted on the crosslinking network and the outer layer of the active component, and the long-chain alkyl hydrophobic layer is formed by grafting long-chain alkane containing mercapto through photocatalytic click chemical reaction. The invention effectively solves the technical problem that the existing catalyst is rapidly deactivated due to the coverage of the active site by the water film in the high-humidity environment.

Inventors

  • XU XIAOHUI
  • ZHU QIUQING
  • GUO JUNLI
  • WEI HAIDI

Assignees

  • 江苏洋井环保服务有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. A water-resistant nitrogen-containing organic waste gas treatment catalyst suitable for use in a normal temperature and high humidity environment, comprising: A micron-sized silica support; an organic-inorganic hybrid crosslinked network coated on the surface of the carrier, wherein the crosslinked network is formed by covalent crosslinking of aldehyde group-containing polyhedral oligomeric siloxane and amino group-containing polyhedral oligomeric siloxane, and the crosslinked network contains free carbon-carbon double bonds; An active component anchored in the crosslinked network, the active component being a mercapto-modified cu—pd bimetallic oxide; And a long-chain alkyl hydrophobic layer grafted on the cross-linked network and the outer layer of the active component, wherein the long-chain alkyl hydrophobic layer is formed by grafting long-chain alkane containing sulfhydryl through photocatalysis click chemical reaction.
  2. 2. The nitrogen-containing organic exhaust gas treatment catalyst according to claim 1, wherein the organic-inorganic hybrid crosslinking network is composed of triethoxy aldehyde polyhedral oligomeric siloxane, amino polyhedral oligomeric siloxane, vinyl aldehyde polyhedral oligomeric siloxane, and vinyl trialkoxysilane crosslinked in situ.
  3. 3. The nitrogen-containing organic exhaust gas treatment catalyst according to claim 2, wherein the mass ratio of the silica carrier, the triethoxy aldehyde-based polyhedral oligomeric siloxane, the amino polyhedral oligomeric siloxane, and the vinyl aldehyde-based polyhedral oligomeric siloxane is 100 (2.4 to 3.2): 3.5 (2.6 to 3.8) in parts by mass.
  4. 4. The catalyst for treating nitrogen-containing organic waste gas according to claim 1, wherein the active component is a Cu-Pd composite metal oxide surface-modified with 3-mercaptopropyltriethoxysilane, and wherein the molar ratio of Cu to Pd is (10-15): 1.
  5. 5. The catalyst for treating nitrogen-containing organic exhaust gas according to claim 1, wherein the long-chain alkane containing mercapto group is one of 1-dodecyl mercaptan, 1-tetradecyl mercaptan, 1-hexadecyl mercaptan and 1-octadecyl mercaptan.
  6. 6. A method for preparing the water-tolerant nitrogen-containing organic exhaust gas treatment catalyst according to any one of claims 1 to 5, comprising the steps of: (1) The carrier pretreatment, namely dispersing micron-sized silicon dioxide in a solvent, adding polyhedral oligomeric siloxane containing aldehyde groups for reflux reaction, and preparing the aldehyde organic-inorganic hybrid silicon dioxide material; (2) The construction of a polymer network, namely, heating the material obtained in the step (1) and amino polyhedral oligomeric siloxane in a solvent for reaction, and then adding aldehyde polyhedral oligomeric siloxane containing carbon-carbon double bonds and a silane coupling agent containing carbon-carbon double bonds for continuous reaction to prepare a functional porous carrier; (3) Preparing and modifying active components, namely preparing Cu-Pd composite metal oxide, and carrying out surface modification on the Cu-Pd composite metal oxide by utilizing a mercapto silane coupling agent to prepare mercapto Cu-Pd composite metal oxide; (4) And (3) long-chain modification and loading, namely carrying out ultraviolet irradiation reaction on the functionalized porous carrier obtained in the step (2) and long-chain alkane containing sulfhydryl in the presence of a photoinitiator, then adding the sulfhydryl Cu-Pd composite metal oxide obtained in the step (3), continuously carrying out click chemistry coupling reaction under ultraviolet irradiation, and drying to obtain the catalyst.
  7. 7. The preparation method of claim 6, wherein in the step (2), the reaction solvent is dimethyl sulfoxide, the reaction temperature in the first stage is 50-70 ℃, the reaction time is 5-9h, the reaction temperature in the second stage after adding the aldehyde POSS containing carbon-carbon double bonds is 50-70 ℃, and the reaction time is 4-8h.
  8. 8. The method according to claim 6, wherein in the step (3), the Cu-Pd composite metal oxide is obtained by alkali precipitation of a mixed solution of palladium chloride and copper nitrate and then calcination at 350-450 ℃ for 2-6 hours.
  9. 9. The method of manufacturing according to claim 6, wherein: Vinyl aldehyde polyhedral oligomeric siloxane is prepared by Friedel-Crafts alkylation reaction of vinyl heptaphenyl polyhedral oligomeric siloxane and methacrolein under the catalysis of anhydrous aluminum chloride; The triethoxy aldehyde polyhedral oligomeric siloxane is prepared by hydrosilylation reaction of vinyl aldehyde polyhedral oligomeric siloxane and triethoxy silane under the action of chloroplatinic acid-isopropanol catalyst; amino polyhedral oligomeric siloxanes are prepared from 3-aminopropyl triethoxysilane by reacting with concentrated hydrochloric acid.
  10. 10. Use of the nitrogen-containing organic exhaust gas treatment catalyst according to any one of claims 1 to 5 for treating normal temperature and high humidity organic exhaust gas, characterized in that: The waste gas is mixed waste gas containing dimethylamine, N-dimethylformamide or butanone, the normal temperature and high humidity environment refers to working conditions with the temperature of 15-35 ℃ and the relative humidity of 80% or more, and the treatment mode is ozone synergistic catalytic oxidation.

Description

Nitrogen-containing organic waste gas treatment catalyst and preparation method thereof Technical Field The invention relates to the technical field of nitrogen-containing organic waste gas treatment, in particular to a water-resistant nitrogen-containing organic waste gas treatment catalyst suitable for a normal-temperature high-humidity environment and a preparation method thereof. Background PU (polyurethane) leather is an artificial leather material widely applied to the fields of bags, clothes, automobiles and the like, and waste gas generated in the production process mainly comprises N, N-Dimethylformamide (DMF), butanone and toluene. In industry, a wet process such as a water washing absorption tower is generally adopted to primarily intercept the volatilized nitrogen-containing organic waste gas. However, the treated tail gas still contains nitrogen-containing organic waste gas such as dimethylamine, DMF droplets and the like with low concentration. Such exhaust gases have strong malodors and high toxicity, and the exhaust gases tend to be in a high humidity and even moisture saturated state. For the high-humidity low-concentration nitrogen-containing organic waste gas, if a traditional high-temperature catalytic combustion method is adopted, the additional heat consumption is extremely high, and nitrogen-containing organic matters are extremely easy to be converted into secondary pollutant nitrogen oxides (NOx) at high temperature. Therefore, the normal temperature/low temperature catalytic oxidation technology (such as the room temperature ozone synergistic catalytic oxidation) becomes the technology with the most application prospect for treating the waste gas. The catalyst used in the existing normal temperature catalysis is mainly noble metal or transition metal oxide. However, the conventional inorganic catalyst has the fatal defect that water vapor is very easy to condense in capillary in micropores of the catalyst to form a water film to cover active sites, so that exhaust gas molecules are prevented from contacting the catalyst, and the catalyst is rapidly deactivated by 'water poisoning'. Therefore, there is a need to develop a novel nitrogen-containing organic exhaust gas treatment catalyst which can maintain high activity in a normal temperature and high humidity environment and can effectively resist moisture interference. Disclosure of Invention Aiming at the technical problems that the existing catalyst for treating nitrogen-containing organic waste gas (such as dimethylamine and the like) is easy to generate capillary water condensation phenomenon due to the hydrophilia of carriers and active components under the working condition of normal temperature and high humidity (such as more than 85 percent RH), so that a water film masks active sites and blocks gas-solid mass transfer, thereby causing rapid deactivation (water poisoning) of the catalyst, incomplete oxidation products (CO) and toxic byproducts (NO x、NH3) to be rapidly increased, the invention provides a water-resistant nitrogen-containing organic waste gas treatment catalyst suitable for normal temperature and high humidity environments and a preparation method thereof. In order to achieve the above purpose, the invention adopts the following technical scheme: A water-resistant nitrogen-containing organic waste gas treatment catalyst suitable for use in a normal temperature and high humidity environment, comprising: A micron-sized silica support; an organic-inorganic hybrid crosslinked network coated on the surface of the carrier, wherein the crosslinked network is formed by covalent crosslinking of aldehyde group-containing polyhedral oligomeric siloxane and amino group-containing polyhedral oligomeric siloxane, and the crosslinked network contains free carbon-carbon double bonds; An active component anchored in the crosslinked network, the active component being a mercapto-modified cu—pd bimetallic oxide; And a long-chain alkyl hydrophobic layer grafted on the cross-linked network and the outer layer of the active component, wherein the long-chain alkyl hydrophobic layer is formed by grafting long-chain alkane containing sulfhydryl through photocatalysis click chemical reaction. Preferably, the organic-inorganic hybrid crosslinking network is formed by in-situ crosslinking of triethoxy aldehyde polyhedral oligomeric siloxane, amino polyhedral oligomeric siloxane, vinyl aldehyde-based polyhedral oligomeric siloxane and vinyl trialkoxysilane. Preferably, the mass ratio of the silica carrier, the triethoxy aldehyde polyhedral oligomeric siloxane, the amino polyhedral oligomeric siloxane and the vinyl aldehyde polyhedral oligomeric siloxane is 100 (2.4-3.2): 3.5 (2.6-3.8) in parts by mass. Preferably, the active component is Cu-Pd composite metal oxide surface-modified by 3-mercaptopropyl triethoxy silane, wherein the mol ratio of Cu to Pd is (10-15): 1. Preferably, the long-chain alkane containing the mercapto group is one o