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CN-122010141-A - Composite ERI molecular sieve and synthetic method and application thereof

CN122010141ACN 122010141 ACN122010141 ACN 122010141ACN-122010141-A

Abstract

The application discloses a composite ERI molecular sieve, and a synthesis method and application thereof, and belongs to the field of molecular sieves. The composite ERI molecular sieve not only has ERI topological structure and uniform submicron faggot-like crystal morphology, but also has silicon aluminum and SAPO regions, and combines the characteristics and advantages of the SAPO-17 and silicon aluminum ERI molecular sieves. The molecular sieve can be used as a denitration catalyst (NH 3 -SCR) after loading Cu 2+ ions, and shows excellent activity and catalyst stability.

Inventors

  • YANG MIAO
  • ZHOU SITONG
  • LI BING
  • TIAN PENG
  • LIU ZHONGMIN

Assignees

  • 中国科学院大连化学物理研究所
  • 榆林中科洁净能源创新研究院

Dates

Publication Date
20260512
Application Date
20241030

Claims (10)

  1. 1. A composite ERI molecular sieve is characterized in that an XRD diffraction pattern of the composite ERI molecular sieve comprises at least X-ray diffraction peaks at the positions listed in the following table No. 2θ 1 7.69±0.1 2 9.73±0.1 3 11.81±0.1 4 13.32±0.1 5 15.70±0.1 6 16.66±0.1 7 19.05±0.1 8 19.53±0.1 9 20.71±0.1 10 21.48±0.1 11 23.81±0.1 12 24.68±0.1 。
  2. 2. The composite ERI molecular sieve according to claim 1, wherein the composite ERI molecular sieve has two phases of SAPO-17 molecular sieve and ERI molecular sieve; wherein the weight of the ERI molecular sieve is 10-300 wt% of the total weight of the SAPO-17 molecular sieve; preferably, the weight of the ERI molecular sieve is 20-100 wt% of the total weight of the SAPO-17 molecular sieve.
  3. 3. The composite ERI molecular sieve according to claim 1, wherein the anhydrous chemical composition of the composite ERI molecular sieve is expressed as: nK·(SixAlyPz)O 72 K represents K + cations in the ERI molecular sieve, n is the mole number of potassium ions in each mole (SixAlyPz) O 72 , and n=0.3-2; x, y and z represent mole fractions of Si, al and P, respectively, and the ranges thereof are x=7 to 31, y=5 to 18, z=3 to 11, and x+y+z=36.
  4. 4. The composite ERI molecular sieve according to claim 1, wherein the composite ERI molecular sieve has a silicon to aluminum ratio of 0.75-3 and a phosphorus to aluminum ratio of 0.38-1.0.
  5. 5. The composite ERI molecular sieve according to claim 1, wherein the composite ERI molecular sieve has uniform crystal morphology, is assembled into a firewood bundle by 10 x 200nm rod-shaped primary particles, and has a secondary particle size of 300-500nm.
  6. 6. The method for synthesizing the composite ERI molecular sieve according to any one of claims 1 to 5, which is characterized by comprising the following steps: S1, obtaining a silicon-aluminum ERI molecular sieve; s2, obtaining a SAPO molecular sieve, roasting to remove a template agent, dissolving in water, ball milling, and drying to obtain a precursor Q; S3, preparing an aqueous solution of N, N, N ', N' -tetramethyl-1, 6-hexamethylenediamine, adding an aluminum source, a phosphorus source, ammonium chloride, a precursor Q and a silicon aluminum type ERI molecular sieve into the aqueous solution, uniformly mixing the aqueous solution to obtain gel, and crystallizing the gel to obtain the composite ERI molecular sieve.
  7. 7. The method of synthesis according to claim 6, wherein in step S2, the high silicon SAPO molecular sieve is selected from at least one of SAPO-34 molecular sieve, SAPO-56 molecular sieve and DNL-6 molecular sieve.
  8. 8. The synthesis method according to claim 6, wherein in the step S3, the mass ratio of the silicon-aluminum ERI molecular sieve to the precursor Q is 0.1-3:1; the mass ratio of the precursor Q to the total amount of the aluminum source and the phosphorus source is 0.5-20:1; the mass ratio of the N, N, N ', N' -tetramethyl-1, 6-hexamethylenediamine aqueous solution to the precursor Q is 1-50:1; the mass percentage of the N, N, N ', N' -tetramethyl-1, 6-hexamethylenediamine aqueous solution is 2% -50%; Preferably, the molar ratio of the phosphorus source to the aluminum source is 0.5-1.5:1; Wherein the mole number of the phosphorus source is calculated by P 2 O 5 , and the mole number of the aluminum source is calculated by Al 2 O 3 ; Preferably, the phosphorus source is selected from at least one of phosphoric acid, ammonium hydrogen phosphate, diamine hydrogen phosphate, monoammonium phosphate; the aluminum source is at least one selected from aluminum oxide, pseudo-boehmite and aluminum hydroxide.
  9. 9. The method according to claim 6, wherein the crystallization condition is that the crystallization temperature is 150-220 ℃ and the crystallization time is 2-72 h; Preferably, after crystallization, the method further comprises the steps of drying and roasting.
  10. 10. The use of the composite ERI molecular sieve according to any one of claims 1 to 5 in ammonia selective reduction denitration reaction after copper ion exchange.

Description

Composite ERI molecular sieve and synthetic method and application thereof Technical Field The application relates to a composite ERI molecular sieve, a synthesis method and application thereof, and belongs to the field of molecular sieves. Background The nitrogen oxide discharged by the tail gas of the diesel vehicle is used as one of urban atmospheric pollutants, so that the problems of environmental pollution such as acid rain, photochemical smog and the like are caused, and the human health is threatened. The selective catalytic reduction technology proposed by Engelhard corporation sprays NH 3 through urea and then uses a catalyst to selectively catalyze and reduce NO X(NH3 -SCR), the reaction efficiency is high, the stability is good, and the technology is the main stream development direction of denitration technology. Because Cu-SSZ-13 has the characteristics of wide temperature window and high hydrothermal stability, NO X which is commercially used for diesel exhaust is removed, but expensive and toxic N, N, N-trimethyl adamantane ammonium hydroxide (TMAdaOH) is required to be used as an organic template for synthesizing the molecular sieve, so that the synthesis cost is high, the energy consumption is high, the environment is polluted, and meanwhile, the low-temperature activity and the stability of the molecular sieve are still to be further improved to meet the increasingly-improved exhaust emission standard. The development of more small pore cage molecular sieves is an important way to promote the low temperature activity of the catalyst NH 3 -SCR. The ERI type (Erionite) molecular sieve consisting of ERI and CAN-D6R cage (generating isolated copper ions) has been favored by researchers. The literature reports a rapidly synthesized ERI-type molecular sieve (Zhu J, liu Z, xu L, et al journal of Catalysis,2020, 391:346-356.) which shortens crystallization time but has poor hydrothermal stability of rapidly synthesized ERI. The silicon content and silicon distribution of the SAPO-17 molecular sieve are difficult to promote and optimize, and the acidity is weak, so that the NH 3 -SCR catalytic effect is limited. Disclosure of Invention In view of the above, the invention provides a composite ERI molecular sieve, a synthesis method and application thereof, and the main purpose is to synthesize a molecular sieve catalytic material with good high and low temperature hydrothermal stability in NH 3 -SCR and wide temperature window. According to a first aspect of the present application, there is provided a composite ERI molecular sieve. A composite ERI molecular sieve comprising an X-ray diffraction peak in an XRD diffractogram of the composite ERI molecular sieve at least at the positions listed in the table below No.2θ17.69±0.129.73±0.1311.81±0.1413.32±0.1515.70±0.1616.66±0.1719.05±0.1819.53±0.1920.71±0.11021.48±0.11123.81±0.11224.68±0.1 Optionally, the composite ERI molecular sieve is provided with two phases of an SAPO-17 molecular sieve and an ERI molecular sieve; Wherein the weight of the ERI molecular sieve is 10-300 wt% of the total weight of the SAPO-17 molecular sieve. Optionally, the weight of the ERI molecular sieve is 20-100 wt% of the total weight of the SAPO-17 molecular sieve. Alternatively, the weight of the ERI molecular sieve is the total weight of the SAPO-17 molecular sieve and the value is independently selected from any of 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 80wt%, 100wt%, 120wt%, 150wt%, 170wt%, 200wt%, 220wt%, 250wt%, 270wt% and 300wt%, or a range of values between any two. Alternatively, the anhydrous chemical composition of the composite ERI molecular sieve is expressed as: nK(SixAlyPz)O72 K represents K + cations in the ERI molecular sieve, n is the mole number of potassium ions in each mole (SixAlyPz) O 72, and n=0.3-2; x, y and z represent mole fractions of Si, al and P, respectively, and the ranges thereof are x=7 to 31, y=5 to 18, z=3 to 11, and x+y+z=36. Optionally, the silicon-aluminum ratio of the composite ERI molecular sieve is 0.75-3, and the phosphorus-aluminum ratio is 0.38-1.0. In the application, the composite ERI molecular sieve contains silicon-aluminum and SAPO regions, the composition is flexible and adjustable, the silicon-aluminum ratio is adjustable between 0.75 and 3, and the phosphorus/aluminum ratio is adjustable between 0.38 and 1.0. Optionally, the composite ERI molecular sieve has uniform crystal morphology, is assembled into a firewood bundle shape by rod-shaped primary particles with the diameter of 10 multiplied by 200nm, and has the secondary granularity of 300-500nm. According to a second aspect of the present application, there is provided a method for synthesizing the composite ERI molecular sieve described above. The synthesis method of the composite ERI molecular sieve comprises the following steps: S1, obtaining a silicon-aluminum ERI molecular sieve; s2, obtaining a SAPO molecular sieve, roasting to remove a template agent, dissolving in