阅读说明：本技术 选择性催化氧化挥发性有机胺的双功能催化剂及制备方法 (Bifunctional catalyst for selectively catalyzing and oxidizing volatile organic amine and preparation method thereof ) 是由 马宏卿 邱继彩 郝晓东 于 2020-06-05 设计创作，主要内容包括：本发明公开了一种选择性催化氧化挥发性有机胺的双功能催化剂及制备方法,属于大气污染控制技术领域。解决了现有催化剂催化效率低,成本高的问题,所述催化剂是由有序介孔的含Zr复合氧化物和位于介孔孔道内的过渡金属氧化物组成。其制备方法包括氧化硅模板以及Cu-硅模板或Cr-硅模板制备；根据所需的金属氧化物组分,将其硝酸溶液和ZrO(NO<Sub>3</Sub>)<Sub>2</Sub>溶解制备混合溶液；加入Cu-硅模板或Cr-硅模板搅拌,向其中滴加浓氨水直至pH为9.8-10.5,经离心和洗涤、烘干、焙烧得固体粉末样品；用NaOH溶液去除固体粉末样品中的含硅模板后即可。本发明可用于选择性催化氧化挥发性有机胺。(The invention discloses a bifunctional catalyst for selectively catalyzing and oxidizing volatile organic amine and a preparation method thereof, belonging to the field of catalystsThe technical field of air pollution control. The catalyst is composed of Zr-containing composite oxide with ordered mesopores and transition metal oxide positioned in mesopore pore channels. The preparation method comprises the steps of preparing a silicon oxide template and a Cu-silicon template or a Cr-silicon template; according to the required metal oxide component, nitric acid solution and ZrO (NO) are added 3 ) 2 Dissolving to prepare a mixed solution; adding a Cu-silicon template or a Cr-silicon template, stirring, dropwise adding concentrated ammonia water until the pH value is 9.8-10.5, centrifuging, washing, drying and roasting to obtain a solid powder sample; and removing the silicon-containing template in the solid powder sample by using NaOH solution. The invention can be used for selectively catalyzing and oxidizing volatile organic amine.)

1. A bifunctional catalyst for selectively catalyzing and oxidizing volatile organic amine is characterized in that: the catalyst consists of an ordered mesoporous Zr-containing composite oxide and a transition metal oxide positioned in a mesoporous pore channel.

2. Bifunctional catalyst for the selective catalytic oxidation of a volatile organic amine according to claim 1, characterized in that: the oxidation active component of the Zr-containing composite oxide, which forms the composite oxide with Zr, is at least one of Ce, La, Co and Mn.

3. Bifunctional catalyst for the selective catalytic oxidation of a volatile organic amine according to claim 2, characterized in that: the transition metal oxide is an oxide of Cu or Cr.

4. Bifunctional catalyst for the selective catalytic oxidation of a volatile organic amine according to claim 2, characterized in that: the oxidation active component forming the composite oxide with Zr accounts for 30-70% of the mass fraction of the catalyst.

5. Bifunctional catalyst for the selective catalytic oxidation of a volatile organic amine according to claim 3, characterized in that: the oxide of Cu or Cr accounts for 1-8% of the mass fraction of the catalyst.

6. A method for preparing a bifunctional catalyst for selective catalytic oxidation of a volatile organic amine according to claim 1, characterized in that:

(1) dissolving a template agent P123 in a hydrochloric acid solution, adding tetraethyl orthosilicate, performing crystallization treatment in a hydrothermal reaction kettle at the temperature of 80-100 ℃, and then washing, drying and roasting to obtain a silicon oxide template;

(2) placing a silicon oxide template in Cu (NO)₃)₂Or Cr (NO)₃)₃In the solution, carrying out ion exchange at 45-55 ℃, carrying out suction filtration, washing, drying in a water bath at 75-85 ℃ for 10-13h, roasting in a muffle furnace for 2-4h to obtain a Cu-silicon template or a Cr-silicon template, and then crushing for later use;

(3) depending on the desired metal oxide component, Ce (NO) is added₃)₃、Co(NO₃)₃、La(NO₃)₃And Mn (NO)₃)₂And ZrO (NO)₃)₂Dissolving and mixing at 45-55 deg.C to prepare mixed solution; after the mixture is cooled to room temperature, adding a Cu-silicon template or a Cr-silicon template into the mixture and stirring the mixture for 2.5 to 3.5 hours, keeping the mixture in a continuous stirring state, dropwise adding concentrated ammonia water into the mixture until the pH value is 9.8 to 10.5, centrifuging and washing the mixture, drying the mixture in a water bath at the temperature of between 75 and 85 ℃ for 10 to 13 hours, and roasting the dried mixture for 2 to 4 hours at the temperature of between 530 and 560 ℃ to obtain a solid powder sample;

(4) stirring 2mol/L NaOH solution at 75-85 ℃ in water bath for 11-13h to remove the silicon-containing template in the solid powder sample, thus obtaining the bifunctional catalyst for selectively catalyzing and oxidizing the volatile organic amine.

7. The method of claim 6, wherein the bifunctional catalyst for selective catalytic oxidation of a volatile organic amine comprises: the muffle furnace roasting temperature in the step (2) is 200-400 ℃.

8. The method for preparing a bifunctional catalyst for selective catalytic oxidation of a volatile organic amine according to claim 6 or 7, characterized in that: using Ce (NO)₃)₃、Co(NO₃)₃、La(NO₃)₃And Mn (NO)₃)₂In the case of two, the mass ratio of the metal components is 2:1 to 8: 1.

9. The method of claim 8, wherein the bifunctional catalyst for selective catalytic oxidation of a volatile organic amine comprises: and (4) in the mixed solution prepared in the step (3), the concentration of metal ions is 0.05 mol/L.

10. The method of claim 9, wherein the bifunctional catalyst for selective catalytic oxidation of a volatile organic amine comprises: cu (NO) used₃)₂Or Cr (NO)₃)₃The concentration of the solution is 0.02-0.3 mol/L.

Technical Field

The invention relates to a bifunctional catalyst for selectively catalyzing and oxidizing volatile organic amine and a preparation method thereof, belonging to the technical field of atmospheric pollution control.

Background

VOCs (volatile organic compounds) are PM2.5 and O which are composite air pollution representative pollutants in China at present₃The reactivity of the precursor is directly related to the contribution of the precursor to the precursor. Organic amine is an important part of high-activity nitrogen-containing VOCs in VOCs, is commonly discharged by waste gas in petrochemical industry, medicine and other industries, and currently CO using a large amount of organic amine₂Trapping technology is also an important input source, and currently, more than 160 types have been detected in the atmosphere. As strong irritant and virulent VOCs, most organic amines are easy to induce human body to generate pathological changes, and have carcinogenic and genotoxicity directly or indirectly; removing PM2.5 and O₃Besides pollution, organic amine also has important contribution to greenhouse effect, and can directly influence the climate by promoting the formation of brown carbon aerogel to cause light scattering or promoting cloud condensation nuclei and the like. Therefore, the organic amine is efficiently controlled and treated, and the PM is lightened in China_2.5And O₃Pollution, improvement of atmospheric environmental quality and maintenance of human health.

Catalytic oxidation technology is one of the most effective technologies of VOCs at present, and mainly utilizes a catalyst to convert pollutants into CO₂And H₂O, effecting its removal in the true sense, but when applied to volatile amines containing nitrogen atoms, NO is ubiquitous_xBy-product problems, especially noble metal catalysts. NO_xHas important contribution to important atmospheric pollution such as photochemical smog, global warming and secondary aerosol, and the like, and has long been in common recognition of direct/indirect toxic effect on human bodies. In addition, the high cost of the noble metal catalyst further restricts the practical application of the noble metal catalyst, and the transition metal oxide catalyst has relatively low cost. Therefore, there is an urgent need to develop a catalyst with high catalytic oxidation activity and volatilizationConversion of nitrogen in amine to N₂(instead of NO)_x) The bifunctional catalyst provided by the invention has relatively low cost, and comprises an oxidation catalyst and a nitrogen oxide reduction catalyst, so that the high-efficiency catalytic oxidation of volatile organic amine can be realized, and NO can be effectively avoided_xFormation of highly active while N₂High selectivity, and ensures the selective catalytic oxidation of the volatile amine in the true sense.

Disclosure of Invention

The invention aims to solve the technical problem of providing a bifunctional catalyst for selectively catalyzing and oxidizing volatile organic amine, which has the advantages of low cost, realization of efficient catalytic oxidation of volatile organic amine and effective prevention of NO_xIs performed.

The invention also provides a preparation method of the bifunctional catalyst for selectively catalyzing and oxidizing the volatile organic amine.

The bifunctional catalyst for selectively catalyzing and oxidizing the volatile organic amine is composed of an ordered mesoporous Zr-containing composite oxide and a transition metal oxide positioned in a mesoporous pore channel.

The oxidation active component of the Zr-containing composite oxide, which forms the composite oxide with Zr, is at least one of Ce, La, Co and Mn. Is an oxidation active component of volatile organic amine in the catalyst.

Further, the transition metal oxide is an oxide of Cu or Cr. Is an active component of the reduction catalyst of nitrogen in organic amine.

Further, the oxidation active component forming the composite oxide with Zr accounts for 30-70% of the mass fraction of the catalyst.

Further, the oxide of Cu or Cr accounts for 1-8% of the mass fraction of the catalyst.

The invention provides a bifunctional transition metal oxide catalyst for selective catalytic oxidation of volatile organic amine, which consists of an ordered mesoporous Zr-containing composite oxide and a Cu oxide positioned in a mesoporous pore channel. Wherein, ZrO_xAs a catalyst carrier, a composite oxide with ZrIs at least one of Ce, Co, La and Mn, the oxides are used as the oxidation component of volatile organic amine, and Cu or Cr oxides in the pore channels are used as the reduction conversion component of nitrogen in the organic amine. Catalyst for effective conversion of volatile organic amine into CO₂And H₂O, with good NO control_xCapability, i.e. high N₂And (4) selectivity.

The preparation method of the bifunctional catalyst for selectively catalyzing and oxidizing the volatile organic amine comprises the following steps:

(1) dissolving a template agent P123 in a hydrochloric acid solution, adding tetraethyl orthosilicate, performing crystallization treatment in a hydrothermal reaction kettle at the temperature of 80-100 ℃, and then washing, drying and roasting to obtain a silicon oxide template;

(2) placing a silicon oxide template in Cu (NO)₃)₂Or Cr (NO)₃)₃In the solution, carrying out ion exchange at 45-55 ℃, carrying out suction filtration, washing, drying in a water bath at 75-85 ℃ for 10-13h, roasting in a muffle furnace for 2-4h to obtain a Cu-silicon template or a Cr-silicon template, and then crushing for later use;

(3) depending on the desired metal oxide component, Ce (NO) is added₃)₃、Co(NO₃)₃、La(NO₃)₃And Mn (NO)₃)₂And ZrO (NO)₃)₂Dissolving and mixing at 45-55 deg.C to prepare mixed solution; after the mixture is cooled to room temperature, adding a Cu-silicon template or a Cr-silicon template into the mixture and stirring the mixture for 2.5 to 3.5 hours, keeping the mixture in a continuous stirring state, dropwise adding concentrated ammonia water into the mixture until the pH value is 9.8 to 10.5, centrifuging and washing the mixture, drying the mixture in a water bath at the temperature of between 75 and 85 ℃ for 10 to 13 hours, and roasting the dried mixture for 2 to 4 hours at the temperature of between 530 and 560 ℃ to obtain a solid powder sample;

(4) stirring 2mol/L NaOH solution at 75-85 ℃ in water bath for 11-13h to remove the silicon-containing template in the solid powder sample, thus obtaining the bifunctional catalyst for selectively catalyzing and oxidizing the volatile organic amine.

The method loads Cu oxide by an ion exchange method by means of a silicon template; further impregnating the Cu-containing silicon template with ZrO (NO)₃)₂And nitrate solutions of Ce, Co, La, Mn and the like by an ammonia precipitation methodAnd drying and calcining the composite precipitate, and removing a template by using NaOH subsequently to obtain the final catalyst. The catalyst provided by the invention has ordered mesoporous channels, wherein Ce, Co, La and Mn related metal oxides are used as oxidation centers, Cu oxide used as a nitrogen selective conversion center accounts for 1-8% of the mass fraction of the catalyst, and double-activity centers in the catalyst jointly ensure that volatile organic amine can obtain higher conversion rate and effectively inhibit by-product NO_xAnd finally, the selective catalytic oxidation is effectively realized.

Further, the muffle furnace roasting temperature in the step (2) is 200-400 ℃.

Further, Ce (NO) is used₃)₃、Co(NO₃)₃、La(NO₃)₃And Mn (NO)₃)₂In the case of two, the mass ratio of the metal components is 2:1 to 8: 1.

Further, in the mixed solution prepared in the step (3), the concentration of the metal ions is 0.05 mol/L.

Further, Cu (NO) used₃)₂Or Cr (NO)₃)₃The concentration of the solution is 0.02-0.3 mol/L.

Compared with the prior art, the invention has the beneficial effects that:

the Zr-containing composite material carrier in the catalyst has the advantages of large specific surface area and porous structure which is beneficial to the rapid diffusion of reactants and products, and organic amine is subjected to catalytic oxidation through the active component of rare earth metal oxide in the composite carrier; the transition metal oxide (Cu or Cr oxide) is loaded in the pore channel to provide a nitrogen reducing component, and the unreacted organic amine on the oxidation site can be utilized to convert the byproduct NO_xIs N₂Thereby ensuring that nitrogen in the volatile amine is efficiently converted into N₂. Thus, the catalyst enhances the catalytic oxidation of N by organic amines₂Selectivity; at the same time, NO_xThe reducing agent which is effectively consumed is unreacted organic amine, so that the overall reaction balance is promoted to move to the right, the catalytic conversion rate of the organic amine is efficiently improved, finally, harmless and efficient removal of the volatile organic amine is realized in the true sense, and the application value is high.

Detailed Description

The present invention is further illustrated by the following specific examples.