CN110354892A - The preparation method of oxide modifying MCM-48 molecular sieve and its application in denitration collaboration demercuration - Google Patents

Abstract

The invention discloses a preparation method of an oxide-modified MCM‑48 molecular sieve and its application in denitrification and mercury removal, and relates to the technical field of molecular sieves. It first pretreats the MCM-48 molecular sieve without template removal; then uses manganese oxide as active material and N oxide as auxiliary agent to synthesize MnN mixed solution; it is added to molecular sieve for impregnation treatment and dried; the dried The final molecular sieve is calcined in air; the oxide-modified MCM‑48 molecular sieve is finally obtained. The oxide-modified MCM-48 molecular sieve prepared by the present invention is subjected to a NOx and ^HgO removal experiment under simulated flue gas atmosphere, and a denitrification and mercury removal efficiency experiment is carried out at different molar ratios of manganese and lanthanum by using different molar ratios. Experiments have proved that it has good mercury removal performance in the low temperature range while removing NOx with high efficiency.

Description

Preparation method of oxide modified MCM-48 molecular sieve and its application in denitrification and mercury removal Applications

technical field

The invention relates to the technical field of molecular sieves, in particular to a method for preparing molecular sieves for denitrification and mercury removal.

Background technique

MCM-48 molecular sieve is a uniform pore size of about 2.6nm, two sets of independent three-dimensional helical surface channel structure, has good long-range periodicity and structural characteristics of stable skeleton, and has good hydrothermal stability and thermal stability. Therefore, it is especially suitable for high-temperature processes, and it is likely to be developed as an excellent industrial catalyst. It has very attractive application prospects in selective catalysis, macromolecular adsorption and separation, etc., and can be used as an adsorbent and catalytic material in industry. And because of its large pore size, it can well adsorb heavy metal ions from wastewater that have a large Hg plasma radius and are not easily adsorbed by microporous molecular sieves. Therefore, it is hopeful to load macromolecular metals to prepare new catalytic materials. MCM-48 molecular sieve has become one of the most important molecular sieve adsorption catalytic materials due to its many unique characteristics in terms of its chemical composition, crystal structure and physical and chemical properties.

NOx and heavy metal Hg, as two typical pollutants in coal combustion flue gas, will cause serious harm to the environment and human health. The discharge of NOx into the atmosphere will produce photochemical smog, acid rain and acid mist, destroy the ozone layer, and have toxic effects on humans and animals. Mercury released from coal combustion mainly exists in the form of elemental mercury (Hg ⁰ ), in addition to compound mercury (Hg ⁺ and Hg ²⁺ ) and particulate mercury. Among them, Hg ²⁺ has high water solubility, and particulate mercury can be captured by the dust collector, so it is easy to remove. However, the removal of Hg ⁰ in the flue gas is difficult to remove, highly polluting, and more harmful to the environment and human beings. Mercury is highly toxic, volatile, and bioaccumulative, and is the most harmful element in the human environment, thus threatening human health. Although the researches on separate denitrification and mercury removal units for coal-fired flue gas are relatively mature; however, in practical engineering applications, if each pollutant is equipped with independent removal facilities, not only the system is complicated, but also the investment and operation costs are greatly increased. Therefore, the existing denitrification facilities can be used to expand the mercury pollutant removal function, and realize the multi-pollutant coordinated control of the integration of denitrification and mercury removal.

Currently, selective catalytic reduction (SCR) is considered to be one of the most effective NOx reduction methods. Typical commercial SCR catalyst V ₂ O ₅ -WO ₃ /TiO ₂ has high denitration efficiency and certain influence on Hg ⁰ removal at high temperature (300-400°C). However, high temperatures not only result in high energy consumption, but also easily lead to the decomposition of the mercury compounds formed. In addition, air pollution control devices ( ^APCDs ) are only used individually in power plants to remove single pollutants such as NO or Hg0, resulting in large investment and high operating costs. Recently, studies have focused on the integration of high-temperature SCR denitrification and mercury removal, and mainly aimed at the synergistic removal efficiency of elemental Hg ⁰ for denitrification catalysts that have been commercially applied at present. Relatively small.

The research on low-temperature denitrification and mercury removal catalysts in the prior art mainly includes:

Application No. 201210221067.9 discloses a composite catalyst for simultaneous denitrification and mercury removal and its preparation method. The catalyst includes an active component and a carrier. The active component is CeO ₂ and ZrO ₂ , wherein the molar ratio of Ce and Zr is 1:0.1～ 1. The carrier is one or more of honeycomb ceramics, molecular sieves, ceramic plates, activated carbon fibers, silica gel carriers, diatomaceous earth, metal alloys, and filter bags. Based on the mass of the carrier, the content of the catalyst active component is 5%-30%. It also includes an auxiliary agent, which is one or any combination of two or more oxides of W, Cu, Fe, Ti, Ni; based on the mass of the carrier, the content of the auxiliary agent is 0% ~15%. The results of flue gas testing show that when the reaction temperature is 300°C, the denitrification rate is 95.6%, and the oxidation rate of gaseous elemental mercury is 92.1%.

Yet also there is following defective in above-mentioned prior art:

Based on the serious impact of dust and SO ₂ on catalyst activity and selectivity in the high-temperature denitrification process, some scholars have proposed a low-temperature SCR denitrification arrangement that places the denitrification reactor behind the dust collector or even the desulfurization unit. The concentration of SO ₂ in the flue gas after the desulfurization tower is lower than 50mg/Nm ³ , and the concentration of dust after dust removal is lower than 20mg/Nm ³ , which weakens the poisoning effect on the catalyst and reduces the deposition and abrasion of the catalyst. However, "Environmental Protection Product Certification Technical Requirements for Small and Medium-sized Oil and Gas Boilers"

(HBC31-2004) stipulates that the exhaust gas temperature of hot water boilers should be less than 180°C, and that of steam boilers and domestic boilers should be less than 200°C. However, the catalyst of the present invention needs to have a denitrification and mercury removal efficiency of over 90% when the reaction temperature is 300°C. At this time, an additional heating device is required, and the required investment and operation costs are large.

Application No. 201610857931.2 discloses a preparation method of a low-temperature, high-efficiency, sulfur-resistant, water-resistant, synergistic denitrification and demercury catalyst. This method uses the directional modification of the surface of the catalyst carrier, optimizes the loading of various metal salts by an equal-volume impregnation method, and then undergoes calcination and pyrolysis to obtain High-efficiency low-temperature denitrification and mercury removal catalyst; the preparation steps are: firstly, the surface groups of the commercial γ-Al ₂ O ₃ carrier are directional modified and modified to obtain the carrier of the catalytic sample; then the carrier is immersed in a metal salt solution of a certain mass concentration , after impregnating for a certain period of time and then drying at low temperature; finally, the dried sample was calcined and pyrolyzed at high temperature to obtain the catalyst. When the carrier was placed in 0.5M hydrochloric acid and sodium hydroxide solution successively, the conversion rates of NOx and Hg ⁰ were respectively 98% and 92% at 240°C, but when SO ₂ was fed alone, the catalyst poisoning could not be recovered.

The existing defective of above-mentioned prior art is:

The catalyst alone has poor resistance to SO ₂ poisoning, and cannot recover after SO ₂ poisoning; strong acid and strong alkali are required in the preparation, and the pH must be adjusted during filtration and washing, and the operation is more complicated.

Due to the different reaction temperature windows of low-temperature denitrification and high-temperature denitrification, and the flue gas composition is also quite different, there is a lack of systematic and in-depth understanding of the catalytic reaction mechanism of low-temperature (100-280°C) denitrification and mercury removal. Further research is needed in the development of new catalysts with high efficiency, good low-temperature activity, and resistance to SO ₂ poisoning, as well as in exploring the influence rules and reasons of impurity gases and dust composition in flue gas on the denitrification and mercury removal performance of catalysts.

Contents of the invention

The object of the present invention is to provide a preparation method of oxide-modified MCM-48 molecular sieve and its application in ^{denitrification} and mercury removal. In addition, the MnN/MCM-48 molecular sieve can convert NOx into N ₂ well in the low temperature range (100-280°C), achieving better denitrification efficiency.

One of tasks of the present invention is to provide a kind of preparation method of oxide modified MCM-48 molecular sieve, and it has adopted following technical scheme:

A kind of preparation method of oxide modified MCM-48 molecular sieve, comprises the following steps successively:

A, the step that the MCM-48 molecular sieve that does not remove template is carried out pretreatment;

b. The step of synthesizing MnN mixed solution with manganese oxide as active material and N oxide as auxiliary agent; said N is La, Co or Ce;

c. Fully mix the MCM-48 molecular sieve pretreated in step a with the MnN mixed solution described in step b, and configure it into a mixed solution with a molar ratio of 2:1, expressed as Mn ₂ N/MCM-48 solution;

d. Stir the Mn ₂ N/MCM-48 solution, and then place it in an oven at 60-80°C for drying;

e. The solid obtained after drying in step d is sequentially roasted, naturally cooled to room temperature, and then transferred to a vacuum drying oven to obtain the final product.

As a preferred version of the present invention, the pretreatment step of step a comprises:

a _1. Dissolve MCM-48 molecular sieves in ethanol, reflux at 60-80°C for 10-14 hours, wash and dry and repeat twice;

a ₂ , dissolving the MCM-48 molecular sieve treated in step a ₁ in n-hexane for ultrasonic treatment;

a _3. Add a certain amount of 3-aminopropyltriethoxysilane drop by drop and then ultrasonicate for a period of time;

a _4. Move the MCM-48 molecular sieve after ultrasonic treatment in step a ₃ into a water bath for condensation and reflux;

a _5. Finally, filter, wash and dry.

As another preferred solution of the present invention, in step b, the specific steps for synthesizing the MnN mixed solution are:

b _1. Weigh a certain amount of manganese-based material and prepare it into 150mL 0.2mol/L Mn(NO ₃ ) ₂ solution;

b _2. Weigh a certain amount of lanthanum-based material and prepare it into 50mL 0.1mol/L La(NO ₃ ) ₂ solution;

b _3. Weigh a certain amount of cobalt-based material and prepare it into 50mL 0.1mol/L Co(NO ₃ ) ₂ solution;

b _4. Weigh a certain amount of cerium-based material and prepare it into 50mL 0.1mol/L Ce(NO ₃ ) ₂ solution;

Mix the Mn(NO ₃ ) ₂ solution with La(NO ₃ ) ₂ solution, Co(NO ₃ ) ₂ solution or Ce(NO ₃ ) ₂ solution to obtain the product.

Further, in step d, stirring for 10-14h and drying for 22-26h.

Further, in step e, the solid obtained after drying in step d is placed in a muffle furnace and calcined at 450-500° C. for 1-4 hours.

Further, the aforementioned N is La. When the MCM-48 molecular sieve is pretreated with template removal followed by amine group, the impregnation method to support manganese and lanthanum (when the molar ratio is 2:1) has good denitrification and mercury removal efficiency.

Further, in step a1, the mass volume ratio of MCM _- 48 molecular sieve and ethanol is ₁ :20g/mL, in step a2, ultrasonic treatment is 10-20min, and in step _a3 , ultrasonic treatment is 20-40min.

Further, in step a4, the temperature of the water bath is 60-80°C, and the condensing and reflux time is _10-14h .

Another task of the present invention is to provide the application of the MCM-48 molecular sieve prepared by the above-mentioned preparation method of the oxide-modified MCM-48 molecular sieve in denitrification and mercury removal.

In the above application, the denitrification and mercury removal temperature is set at 100-240°C, and when the temperature is 100°C-240°C, the denitrification and mercury removal rate of MCM-48 molecular sieve is above 90%.

The main reaction principle of the preparation method of oxide modified MCM-48 molecular sieve of the present invention is:

First, in the pretreatment step of the MCM-48 molecular sieve without the template agent removed, the MCM-48 molecular sieve without the template agent removed was refluxed in an ethanol water bath at 60-80°C for about 12 hours, repeated twice and washed and dried to Remove the template agent of the molecular sieve without destroying the hydroxyl groups on the surface of the molecular sieve, and then activate and modify the inner and outer surfaces of the molecular sieve to introduce amino groups; after that, the active material is evenly dispersed on the MCM-48 molecular sieve, specifically manganese, lanthanum, cobalt, and cerium Evenly disperse to MCM-48 molecular sieve, the specific steps are: first mix the solution containing manganese and lanthanum (cobalt, cerium) according to the molar ratio Mn:La(Co, Ce)=2:1, then add molecular sieve and stir at room temperature For about 12 hours, the purpose is to prevent the active substance from clustering on the molecular sieve, and directly put the mixed solution into an oven at about 80°C for drying to ensure that the active substance is dispersed on the molecular sieve without waste; finally, load it on the molecular sieve The active material of the active material turns into an oxide. The specific steps are to put the dried solid in step d into a muffle furnace at about 450-500 ° C for about 2 h to make manganese, lanthanum, cobalt, and cerium into their corresponding oxides. thing.

Compared with the prior art, the present invention has brought beneficial technical effects:

The oxide-modified MCM-48 molecular sieve prepared by the present invention has shown unique characteristics in physics and chemistry, and can remove NOx with high efficiency (75-100%) in the low temperature range (100-300°C) , has good mercury removal performance.

Mesoporous materials not only have the characteristics of large pore size, specific surface area and large pore volume, but also are rich in silanol, which exists on the inner and outer surfaces of the pores, and the presence of silanol provides good activity for the surface modification of mesoporous materials. Point; metal oxides are active components, metals are widely sourced, cheap, and the method of converting them into oxides is simple. The method of the invention is simple, does not require high equipment, and can be industrialized.

Beneficial technical effect of the present invention also can further embody from the following examples, and the embodiment has studied the impact of different metal loads on MCM-48 molecular sieves on NOx and mercury removal efficiency, research shows, when modified MCM-48 molecular sieves are manganese And lanthanum oxide, when the molar ratio of manganese and lanthanum is 2:1, the denitrification and mercury removal rate of oxide modified MCM-48 molecular sieve is above 95%.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is the XRD diffractogram of the raw material MnO of Example ₁ of the present invention and the final prepared MnLa _0.5 /MCM-48 catalyst;

Fig. 2 is a diagram of the denitrification and mercury removal efficiencies of the MnLa _0.5 /MCM-48 catalyst of Example 1 of the present invention at different temperatures.

Detailed ways

The present invention proposes a preparation method of an oxide-modified MCM-48 molecular sieve and its application in synergistic denitrification and mercury removal. In order to make the advantages and technical solutions of the present invention clearer and clearer, the present invention will be described in conjunction with specific examples below. Detailed description.

The raw materials required by the present invention can be purchased through commercial channels.

The evaluation method of catalyst activity of the present invention is as follows:

Detection method: The detection system of fixed bed reactor, flue gas analyzer and mercury detector is adopted.

Sorbent activity detection steps:

The prepared oxide modified MCM-48 molecular sieve 4cm ³ catalyst is placed in the tube furnace of the fixed bed reactor, and a mass flow meter is used to control the flow of N ₂ , NO, NH ₃ , O ₂ at the gas inlet, adjust For SCR equipment, use a flue gas analyzer to measure the concentration of NO in the flue gas; the temperature of the mercury generator water bath is controlled at 30°C, and use a mercury detector to measure the concentration of mercury vapor.

Evaluation method: The denitrification efficiency can be obtained by the change of NO concentration in the flue gas before and after. The calculation method is as formula (1):

The denitrification efficiency is obtained by the change of NO concentration in flue gas before and after. The calculation method is as formula (2):

Example 1:

The first step, first dissolve the MCM-48 molecular sieve in ethanol and reflux, wash and dry and repeat twice, then dissolve it in n-hexane and ultrasonically disperse, and add 3-aminopropyltriethoxysilane (APTES) drop by drop ) to continue ultrasonication for 30 minutes; finally, move the treated MCM-48 molecular sieve into a water bath to reflux for 12 hours, filter, wash and dry, for use in subsequent experiments.

The second step, pretreatment of manganese-based and lanthanum-based materials: weigh 2.5g of 50% Mn(NO ₃ ) ₂ solution, and configure 50mL solution in a beaker; weigh 1.02g La(NO ₃ ) ₂ ·6H ₂ O , configure a 50mL solution in a beaker; mix the two solutions thoroughly, which means MnLa _0.5 solution;

Step 3: Weigh 5g of the treated MCM-48 molecular sieve, add it into the beaker of Mn ₂ La solution, and mix well;

Step 4: Put the mixed solution in a magnetic stirrer, stir at a constant speed at room temperature for 12 hours, and then put the mixed solution in an oven at 80°C to dry for 24 hours;

Step 5: Put the dried solid in a muffle furnace at 450°C for 5 hours and then cool it down to room temperature in the muffle furnace, grind it to about 80-100 mesh and transfer it to a vacuum drying oven In the process, the Mn ₂ La/MCM-48 catalyst is obtained.

The denitrification and mercury removal experiments were carried out on the Mn ₂ La/MCM-48 catalyst prepared in this example. The experimental results showed that the denitrification efficiency was about 99% and the mercury removal efficiency was about 96% at 140-240°C, as shown in FIG. 2 . The diffraction patterns of the MCM-48 molecular sieve and the finally prepared Mn ₂ La/MCM-48 catalyst are shown in FIG. 1 . By comparing the two curves, it is found that the small diffraction peaks appearing on Mn ₂ La/MCM-48 are the diffraction peaks of manganese oxide and lanthanum oxide.

Example 2:

The difference from Example 1 is that

The mixed solution in the second step is Mn ₂ Co solution.

Select simulated flue gas with NO content of 0.1%, NH content of 0.12%, O content of _{5 %} , and the rest of N as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ₀ steam is obtained in the mercury permeation tube ^. The flow rate of the Hg ⁰ carrier gas is 90mL/min, the total gas flow rate is 667mL/min, the space velocity is 10000h ^-1 , and the denitrification and mercury removal experiments are carried out in the temperature range of 100-260°C. Experimental results The denitrification efficiency is about 95% at 160-240°C, and the mercury removal efficiency is about 94%.

Example 3:

The difference from Example 1 is that

The mixed solution in the second step is a Mn ₂ Ce solution.

Select simulated flue gas with NO content of 0.1%, NH content of 0.12%, O content of _{5 %} , and the rest of N as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ₀ steam is obtained in the mercury permeation tube ^. The flow rate of the Hg ⁰ carrier gas is 90mL/min, the total gas flow rate is 667mL/min, the space velocity is 10000h ^-1 , and the denitrification and mercury removal experiments are carried out in the temperature range of 100-260°C. Experimental results The denitrification efficiency is about 95% at 160-240°C, and the mercury removal efficiency is about 92%.

From the above examples 1 to 3, it can be seen that the denitrification and mercury removal temperature range of the present invention should be controlled at 160-240 °C, and the manganese-lanthanum oxide modified MCM-48 catalyst has the best denitrification and mercury removal efficiency, and the temperature window is wider.

The difference in space velocity also affects the denitrification and mercury removal efficiency.

The invention studies the influence of preparing manganese-lanthanum oxide modified MCM-48 catalyst on denitrification and mercury removal performance.

Example 4:

The difference from Example 1 is that the molar ratio of loaded manganese to lanthanum is 2:1.

Select simulated flue gas with NO content of 0.1%, NH content of 0.12%, O content of _{5 %} , and the rest of N as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ₀ steam is obtained in the mercury permeation tube ^. The flow rate of Hg ⁰ carrier gas is 150mL/min, the total gas flow rate is 1000mL/min, and the space velocity is 30000h ^-1 . The denitrification and mercury removal experiments are carried out. The experimental results show that the denitrification efficiency is about 100% at 120-240℃ The efficiency is about 98%.

Example 5:

The difference from Example 1 is that the molar ratio of loaded manganese to lanthanum is 2:1.

Select simulated flue gas with NO content of 0.1%, NH content of 0.12%, O content of _{5 %} , and the rest of N as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ₀ steam is obtained in the mercury permeation tube ^. The flow rate of the Hg ⁰ carrier gas is 225mL/min, the total gas flow rate is 1500mL/min, the space velocity is 45000h ^-1 , and the denitrification and mercury removal experiments are carried out in the temperature range of 100-260°C. The experimental results show that the denitrification efficiency is about 100% at 140-240°C, and the mercury removal efficiency is about 99%.

It can be seen from the above examples 1, 4 and 5 that the catalyst of the present invention will also have a certain influence on denitrification and mercury removal due to different space velocities, and the higher the space velocity, the better the efficiency.

The addition of sulfur dioxide also has an impact on denitrification and demercury removal.

The invention studies the influence of preparing manganese-lanthanum oxide modified MCM-48 catalyst on denitrification and mercury removal performance.

Embodiment 6:

The difference from Example 1 is that the molar ratio of loaded manganese to lanthanum is 2:1.

Select simulated flue gas with NO content of 0.1%, NH content of 0.12%, O content of _{5 %} , and the rest of N as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ₀ steam is obtained in the mercury permeation tube ^. The flow rate of Hg ⁰ carrier gas is 90mL/min, the total gas flow rate is 667mL/min, and the space velocity is 10000h ^-1 . After the experiment is carried out for a period of time, 500ppm SO ₂ is introduced. After about 30 hours, the SO ₂ is stopped. The denitrification and demercuration experiments were carried out in the temperature range of 140°C. The experimental results show that the denitrification efficiency is about 89% and the mercury removal efficiency is about 88% after SO ₂ is fed; the denitrification efficiency is 95% and the mercury removal efficiency is 93% after the SO ₂ is stopped for 1 hour.

It can be known from Example 1 and Example 6 that the MnLa _0.5 /MCM-48 catalyst prepared by the present invention has good sulfur resistance when the molar ratio of loaded manganese to lanthanum is 2:1 and the temperature is controlled at 140°C.

Comparative example 1:

The difference from Example 1 is:

The specific steps of the second step are: pretreatment of manganese-based and lanthanum-based materials: weigh 2.5g of 50% Mn(NO ₃ ) ₂ solution, and configure 50mL solution in a beaker; weigh 2.04g of La(NO ₃ ) ₂ · 6H ₂ O, configure 50mL solution in a beaker; mix the two solutions well, which means MnLa solution;

Finally, the MnLa/MCM-48 catalyst with a manganese-lanthanum molar ratio of 1:1 was prepared.

The MnLa/MCM-48 catalyst prepared in this comparative example with a manganese-lanthanum molar ratio of 1:1 was used for denitrification and mercury removal experiments, and the NO content of the simulated flue gas was selected to be 0.1%, the NH content was 0.12%, and the O content was _{5 %} . , and the rest is N ₂ as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ⁰ vapor is obtained in the mercury permeation tube. The flow rate of Hg ⁰ carrier gas is 90mL/min, the total gas flow is 667mL/min, and the space velocity It is 10000h ^-1 , and the denitrification and mercury removal experiment is carried out in the temperature range of 100-260°C. Experimental results The denitrification efficiency is about 95% at 140-240°C, and the mercury removal efficiency is about 92%.

Comparative example 2:

The difference from Example 1 is:

The specific steps of the second step are: pretreatment of manganese-based and lanthanum-based materials: weigh 2.5g of 50% Mn(NO ₃ ) ₂ solution, and configure 50mL solution in a beaker; weigh 2.04g of La(NO ₃ ) ₂ · 6H ₂ O, configure 50mL solution in a beaker; mix the two solutions well, it means Mn _0.5 La solution;

Finally, the Mn _0.5 La/MCM-48 catalyst with a molar ratio of manganese to lanthanum of 1:2 was prepared.

The MnLa ₂ /MCM-48 catalyst prepared in this comparative example with a molar ratio of manganese to lanthanum of 1:2 was used for denitrification and mercury removal experiments. The simulated flue gas NO content was 0.1%, NH ₃ content was 0.12%, and O ₂ content was 5 %, and the rest is _N2 as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ⁰ vapor is obtained in the mercury permeation tube. The flow rate of Hg ⁰ carrier gas is 90mL/min, and the total gas flow is 667mL/min. The speed is 10000h ^-1 , and the denitrification and mercury removal experiment is carried out in the temperature range of 100-260°C. Experimental results The denitrification efficiency is about 95% at 140-240°C, and the mercury removal efficiency is about 91%.

Comparative example 3:

The difference from Example 1 is:

The specific steps of the second step are: pretreatment of manganese-based and lanthanum-based materials: weigh 2.5g of 50% Mn(NO ₃ ) ₂ solution, and configure 50mL solution in a beaker; weigh 2.04g of La(NO ₃ ) ₂ · 6H ₂ O, configure 50mL solution in a beaker; mix the two solutions well, it means Mn _0.5 La solution;

Finally, the MnLa ₃ /MCM-48 catalyst with a manganese-lanthanum molar ratio of 1:3 was prepared.

The MnLa ₃ /MCM-48 catalyst prepared in this comparative example with a molar ratio of manganese to lanthanum of 1:3 was used for denitrification and mercury removal experiments. The NO content of the simulated flue gas was selected to be 0.1%, the NH content was 0.12 _% , and the O content was ₅ %, and the rest is _N2 as balance gas. At the same time, by changing the temperature of the water bath, a certain concentration of Hg ⁰ vapor is obtained in the mercury permeation tube. The flow rate of Hg ⁰ carrier gas is 90mL/min, and the total gas flow is 667mL/min. The speed is 10000h ^-1 , and the denitrification and mercury removal experiment is carried out in the temperature range of 100-260°C. Experimental results The denitrification efficiency is about 94% at 140-240°C, and the mercury removal efficiency is about 91%.

The parts not mentioned in the present invention can be realized by referring to the prior art.

It should be noted that any equivalent or obvious modification made by those skilled in the art under the teaching of this specification shall fall within the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of oxide modifying MCM-48 molecular sieve, which is characterized in that successively the following steps are included:

A, pretreated step is carried out to the MCM-48 molecular sieve of non-removed template method；

B, using Mn oxide as active material, N oxide is as auxiliary agent, the step of synthesizing MnN mixed solution；The N is La, Co or Ce；

C, MnN mixed solution described in the pretreated MCM-48 molecular sieve of step a and step b is sufficiently mixed uniformly, configuration The mixed solution for being 2:1 at molar ratio, is expressed as Mn₂N/MCM-48 solution；

D, to the Mn₂N/MCM-48 solution is stirred, and is then placed it in 60-80 DEG C of baking oven and is dried；

E, obtained solid after step d drying is successively fired, after cooled to room temperature, is transferred in vacuum oven, i.e., ?.

2. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 1, which is characterized in that step The pre-treatment step of a includes:

a₁, MCM-48 molecular sieve is dissolved in ethyl alcohol, 60-80 DEG C of reflux 10-14h of temperature, be repeated twice after washing is dry；

a₂, by step a₁MCM-48 molecular sieve that treated, which is dissolved in n-hexane, to be ultrasonically treated；

a₃, dropwise be added dropwise a certain amount of 3- aminopropyl triethoxysilane be then sonicated a period of time；

a₄, by step a₃MCM-48 molecular sieve after sonicated moves into water-bath and is condensed back；

a₅, last filtration washing it is dry.

3. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 2, it is characterised in that: step In b, the specific steps of MnN mixed solution are synthesized are as follows:

b₁, weigh a certain amount of Mn-based material, and be configured to the Mn (NO of 150mL0.2mol/L₃)₂Solution；

b₂, weigh a certain amount of lanthanum sill, and be configured to the La (NO of 50mL0.1mol/L₃)₂Solution；

b₃, weigh a certain amount of cobalt-based material, and be configured to the Co (NO of 50mL0.1mol/L₃)₂Solution；

b₄, weigh a certain amount of cerium sill, and be configured to the Ce (NO of 50mL0.1mol/L₃)₂Solution；

By the Mn (NO₃)₂Solution and La (NO₃)₂Solution, Co (NO₃)₂Solution or Ce (NO₃)₂Solution mixing to get.

4. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 3, it is characterised in that: step In d, 10-14h, dry 22-26h are stirred.

5. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 4, it is characterised in that: step In e, obtained solid is placed in Muffle furnace in 450-500 DEG C of roasting 1-4h after step d is dry.

6. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 5, it is characterised in that: described N be La.

7. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 2, which is characterized in that step a₁In, the quality volume proportion of MCM-48 molecular sieve and ethyl alcohol is 1:20g/mL, step a₂Middle ultrasonic treatment 10-20min, step a₃Middle ultrasonic treatment 20-40min.

8. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 2, it is characterised in that: step a₄In, the temperature of water-bath is 60-80 DEG C, and the condensing reflux time is 10-14h.

9. a kind of preparation method of oxide modifying MCM-48 molecular sieve according to claim 1-5 is prepared MCM-48 molecular sieve denitration collaboration demercuration in application.

10. application according to claim 9, it is characterised in that: denitration demercuration temperature is set as 100-260 DEG C.