CZ201992A3 - Process for producing a catalytically active layer on zeolite foam - Google Patents

Abstract

A method for producing a catalytically active layer on a zeolite foam is characterized by immersing an alkaline-activated zeolite foam, in particular in the form of pellets or grit, for 1 to 12 hours in a solution of at least one inorganic salt at a concentration of 0.05 to 1 mol / d at temperature. 25-100 ° C. It is allowed to react for 1 to 10 hours. Thereafter, the reacted zeolite foam is washed with demineralized water, dried at 80 to 250 ° C for 4 to 12 hours and then optionally calcined at 300 to 600 ° C for 4 to 10 hours. The inorganic salts are water-soluble nitrates, sulphates or chlorides containing at least some of the cations Ag, Cu, ZrO, Co, Ni, Zn, Mn, Ca, Mg, Al, Fe, Ga, In, Cr, Y, Sn, Cea lanthanide cations.

Description

Process for the production of a catalytically active layer on zeolite foam

Field of technology

The invention relates to a process for the production of a catalytically active layer on a zeolite foam, on the outer and inner surfaces of the pellets or crumbs of the alkali-activated zeolite foam.

Prior art

Of the prior art methods for producing catalytically active hydroxide and oxide layers on the surface of shaped supports based on aluminosilicates and other materials, impregnation is the most widely used. During impregnation, the support is allowed to soak in the entire volume with a solution containing compounds of the desired metal or metals in the form of a soluble precursor. Subsequent thermal decomposition of the precursor forms an oxide layer on the surface of the support. The disadvantage of this method of production is usually the possibility of producing only oxide layers, and only on the entire inner surface of the support.

By modifying this prior art production method, catalysts or sorbents with an oxide layer at a certain depth of the shaped support can be produced. These are the so-called egg-shell catalysts described, for example, in the Czech utility model CZ 27243 U1 (Hydrogenation catalyst N1 / AI2O3 egg-shell type). The disadvantage of this method of production is its complexity and the fact that it usually allows only the oxide layer to be produced.

Another prior art method of making a hydroxide layer on the outer and inner surfaces of a support involves homogeneous precipitation, in which the support is heated in a precursor solution containing a substance, the heating of which gradually decomposes (hydrolysis) to form a suitable precipitant. Urea is most often used for this current method of production, the resulting hydroxides being converted to oxides by annealing. A disadvantage of said production method, which is described, for example, in U.S. Pat. No. 4,113,658 A, is the possibility of producing hydroxide layers only on the entire surface of the support, both external and internal.

These disadvantages are at least partially eliminated by the process for the production of a catalytically active layer on a zeolite foam according to the invention.

The essence of the invention

The process for producing a catalytically active layer on a zeolite foam is characterized in that the alkali-activated zeolite foam is immersed for 1 to 12 hours in a solution of at least one inorganic salt having a concentration of 0.05 to 1 mol / dm ³ at a temperature of 25 to 100 ° C. in which it is allowed to react for 1 to 10 hours, then the reacted zeolite foam is washed with demineralized water and then at least dried at 80 to 250 ° C for 4 to 12 hours to form a hydroxide layer on the zeolite foam.

A preferred method of producing a catalytically active layer on a zeolite foam is characterized in that the alkali-activated zeolite foam is in at least one form selected from the group consisting of pellets and crumb.

Another preferred method of producing a catalytically active layer on a zeolite foam is characterized in that the at least one inorganic salt is at least one water-soluble salt containing cations selected from the group consisting of Ag ⁺ , Cu ²⁺ , ZrO ² cations. Co ²⁺ , Ni ²⁺ , Zn ²⁺ , Mn ²⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Fe ³⁺ , Ga ³⁺ , In ³⁺ , Cr ³⁺ , Y ³⁺ , Sn ^{4 +} , Ce ⁴⁺ and trivalent cations of lanthanides.

- 1 CZ 2019 - 92 A3

Another preferred method of producing a catalytically active layer on a zeolite foam is characterized in that the at least one inorganic salt is at least one water-soluble salt selected from the group consisting of nitrates, sulfates and chlorides.

Another preferred method of producing a catalytically active layer on a zeolite foam is characterized in that the reacted zeolite foam is calcined at 300 to 600 ° C for 4 to 10 hours after drying to form an oxide layer on the zeolite foam.

In many catalytic and sorption applications, it is advantageous, for example for reasons of diffusion, precursor cost or better heat dissipation, that the active metal or metal compounds are not homogeneously distributed on the support but form a layer at a certain depth of the support used. By the process for the production of the catalytically active layer on the zeolite foam according to the invention, it is possible to prepare hydroxide or after annealing the oxide layer in the required depth of pellets or crumb of alkali-activated zeolite foam, which can be formed eg in the production of pellets of alkali-activated zeolite foam as a so-called sub-sieve, or when crushing a large block of alkali-activated zeolite foam, which is the simplest and cheapest method for obtaining alkali-activated zeolite foam particles. The properties of these layers can be controlled using the appropriate concentration of inorganic salt, or a mixture of inorganic salts, the reaction temperature and the reaction time. The formation of the catalytically active layer on the zeolite foam according to the invention occurs due to the gradual diffusion of alkalis (hydroxides, carbonates and silicates of sodium and potassium) which are present in the support after alkaline activation. During the production of the catalytically active layer on the zeolite foam according to the invention, these alkalis reach the surface, where they react with the corresponding inorganic salt to form the corresponding hydroxide or oxide in the form of a catalytically active layer.

The process for producing the catalytically active layer on the zeolite foam according to the invention is variable; allows to prepare catalytically active layers with one or more elements. At the same time, it is possible to use all water-soluble cations which precipitate with alkaline (hydroxide) solutions for the process for the production of the catalytically active layer on the zeolite foam according to the invention. For the process for the production of the catalytically active layer on the zeolite foam according to the invention, it is possible to use, for example, solutions containing cations Ag ⁺ , Pb ²⁺ , Hg ²⁺ , Cu ²⁺ , Cd ²⁺ , ZrO ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ^{2 +} , Mn ²⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Fe ³⁺ , Ga ³⁺ , In ³⁺ , Cr ³⁺ , Y ³⁺ , Bi ³⁺ , Sn ⁴⁺ and a group of trivalent and tetravalent lanthanide cations, eg Ce, Pr, La, Eu, some of which are not used in catalysis or sorption. After completion of the reaction, the residual mother liquor is removed by washing with demineralized water and the product is dried or annealed according to the desired application.

Inorganic salts in the form of chlorides and sulphates, most preferably nitrates, can be used for the preparation of solutions, since after thermal decomposition they do not leave other impurities (chlorides or sulfur in the form of sulphates) in the prepared catalytically active layer, which are often undesirable.

Compared to prior art processes, the process for producing a catalytically active layer on a zeolite foam according to the invention has the advantage that (i) it is simple, inexpensive, technologically and energy-efficient, (ii) allows layers and mixed layers with a defined profile in the pellet. (iii) allows the use of conventional equipment for the preparation or production of catalysts and sorbents; and (iv) allows the use of commonly available raw materials and materials.

Examples of embodiments of the invention

Example 1

The process for producing a catalytically active layer on zeolite foam is carried out by immersing the pellets of alkali-activated zeolite foam in a solution of the corresponding inorganic salt or a mixture thereof with parameters according to the desired composition of the resulting hydroxide layer (see Table 1). During the reaction, the heated solution is kept in motion by a shaft stirrer above the layer of pellets in order to prevent their mechanical damage by abrasion, but at the same time to ensure sufficient

-2 EN 2019 - 92 A3 flow of solution around the pellets. At the end of the process, the pellets are washed on the nets with demineralized water and further dried in a thin layer (see Table 1).

Table 1 - Parameters of the method of production of catalytically active layer on zeolite foam

Solution number Inorganic salt Solution concentration [mol / dm ³ ] Solution temperature [= C] Reaction time [h] Drying temperature [° C] Drying time M Note 1 A1 (NOj) 3 9 H ₂ O 0.25 80 5 120 6 7 Co (NO ₃ ) ₂ 6 H ₂ O 0.25 80 5 120 6 3 Mg (NO j) δ H ₂ O 0.25 80 5 120 6 4 Mn (NO ₃ ) ₂ 4 H ₂ O 0.25 80 5 120 6 5 Mh (NO ₃ ) ₂ 4 H ₂ O 0.05 80 5 120 6 6 Mn (NO ₃ ) ₂ 4 H _: O 0.40 80 5 120 6 7 Mn (NOj) ₂ 4 H ₂ O 1.00 40 5 220 10 8 (Π (ΝΌ ₂ ) ₂ 4 H> O 0.25 80 1 80 6 9 Mn (NO ₃ ) ₂ '4 H ₂ O 0.25 90 10 80 6 10 Cu (NO ₂ ) ₂ 3 HjO 0.25 80 5 120 6 11 ZiOCl ₂ 8 H ₂ O 0.25 80 5 120 6 12 Ni (NO ₃ ) ₂ 6 H ₂ O 0.25 80 5 120 6 13 SnCL 5 H ₂ O 0.25 80 5 120 6 14 Fe (NO ₃ ) with 9 H ₂ O 0.25 80 5 120 6 15 CriNOA; 9 H ₂ O 0.25 80 5 120 6 16 CuSO ₄ · 5 H ₂ O 0.25 80 5 120 6 17 AgNO ₅ 0.25 80 5 120 6 18 Co (KO ₃ } ₂ 6 H ₂ O Mn (NO ₃ ) ₂ '9 H ₂ O 0.25 80 5 120 6 Mol. ratio Co / =η = 1: 1 19 Mg (NO ₃ ) ₂ 6 H ₂ O A1 (NO,> 4 H, O 0.05 80 5 120 6 Mol. ratio Mg / Al = 3: 1 20 Mg (NO ₃ ) ₂ 6 H ₂ O Al (NO, h 9 H _? O 0.25 80 5 120 6 Mol. ratio Mg / Al = 4: 1

CZ 2019 - 92 A3

Table 2 - Chemical composition of the obtained zeolite foams with a catalytically active layer

Number solution Chemical composition (% by weight) M _S O ,, oxide Note SiCb AbO? K? O Fe ₂ O ₃ CaO On? O MgO MA 0 68.7 9.7 8.4 1.3 3.1 4.0 4 _; 3 0.0 - Entrance zeoiite foam 1 73.0 13.7 5.3 1.4 2.5 0.6 3.1 0.0 - 2 68.9 9.8 5.3 1.4 2.7 0.8 4.3 6.5 CoO 3 70.5 10.0 5.2 1.4 2.7 0.6 9.2 0.0 - 4 69.0 9.9 $ '2 1.4 2.8 0.7 3.9 6.7 MnO 5 69.7 10.0 7.0 1.3 3.1 2.2 4.6 1.7 MnO 6 68.9 9.8 5.0 1.3 2.6 0.7 3.4 7.9 MnO 7 67.7 9.6 5.5 1.4 2.6 1.0 3.6 8.4 MnO 8 69.3 9.9 6.3 1.3 3.2 1.4 4.2 4.1 MnO 9 68.8 9.9 4.9 1.4 2.6 0.6 3.7 7.8 MnO 10 65.9 9.7 4.8 1.3 2.3 0.4 3.9 11.3 CuO 11 79.4 10.3 4.5 1.3 1.5 0.4 0.9 1.2 ZrO? 0.1% C1 12 69.0 9.9 5 _; 3 1.4 2.6 0.6 4.0 6.7 NO 13 84.4 8.3 3.2 1.1 0.8 0.4 0.4 1.0 SnO? 0.1% C1 14 73.9 10.1 4.4 7.9 1.5 0.4 1.3 0.0 Fe? O ₃ 15 73.2 10.3 5.4 1.4 2.6 0.5 2.9 3.2 Cr? Oj 16 65.2 9.5 5.6 1.2 2.6 0.8 4.2 8.9 CuO 1.7% SOj 17 64.5 9.1 4.2 1.2 2.2 0.4 3.9 14.2 Ag? O 18 68.0 9.6 4.5 1.4 2.3 0.5 2.9 6.8 CoO 3.6% MnO 19 71.1 10.9 6.2 1.4 3.1 1.0 6.0 - - 20 71.4 12.2 5.2 1.4 2.8 0.6 6.1 - -

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Table 3 - Character of catalytically active layers

Number solution Layer depth (mm) Metal oxide content in pellet (% by weight.) Theoretical content of metal oxide in the layer (% by weight.) Layer description 1 - 4.0 * - Higher AI content throughout the profile. 2 0.25 6.5 34.2 Sharp maximum at a depth of 0.15 to 0.25 mm. 3 0.75 4.9 ’ 9.6 Blurred maximum, higher Mg content in the whole profile. 4 0.60 6.7 15.9 Sharp maximum at a depth of 0.45 to 0.6 mm. 5 0.10 AT 21.7 Sharp maximum at a depth of 0.1 mm. 6 2.50 7.9 - Mn in the whole profile, blurred maximum at a depth of 0.3 to 1 mm. 7 2.50 8.4 - Mu in the entire profile, blurred maximum at a depth of 0.1 to 0.7 mm. 8 0.65 4.1 9.1 Blurred maximum around 0.3 mm, Mu content then gradually decreases. 9 2.50 7.8 - Mu in the whole profile, maximum at a depth of 0 to 0.5 mm, the Mn content then gradually decreases. 10 0.70 11-3 23.5 Blurred maximum at a depth of 0.1 to 0.4 mm, the Cu content then gradually decreases. if 1.40 1.-2 1.5 Blurred maximum at a depth of 0.2 to 0.6 mm, the Zr content then gradually decreases. 12 0.75 6.7 13.1 Maximum, at a depth of 0.15 to 0.3 mm, the Ni content then gradually decreases. 13 2.50 1.0 - Blurred maximum at a depth of 0 to 0.3 am, the Sn content then gradually decreases. 14 0.50 6.6 ’ 18.3 Blurred maximum at a depth of 0 to 0.3 mm, the Fe content then gradually decreases. 15 0.90 3 2 7.3 An insulated layer inside the material at a depth of 0.2 to 0.9 mm. 16 0.40 8.9 30.2 Sharp maximum at a depth of 0.2 to 0.4 mm. 17 2.50 14 ,? - Ag in the whole profile, maximum at a depth of 0.2 to 0.6 mm, then the Ag content gradually decreases. 18 0.30 6.8 / 3.6 * 30.1 / 16.0 Maximum. at a depth of 0 to 0.3 mm, Mn sharp maximum at a depth of 0.2 to 0.3 mm. 19 0.90 1.2 / L7 ~ * 2.0 / 2.9 Blurred maximum at a depth of 0.6 to 0.9 mm, higher content of Mg and Al in the entire profile. 20 0.80 2,571.8 *** 4,773.3 Blurred maximum at a depth of 0.2 to 0.8 mm, higher content of Mg and AI in the whole profile.

* difference in content (sample with layer - input zeolite foam) * * CoO / MnO *** MgO / AhCh ίο Example 2

The process for producing the catalytically active layer on the zeolite foam was carried out in the same manner as in Example 1, except that the obtained material was calcined at 350 ° C for 4 hours.

CZ 2019 - 92 A3

Example 3

The process for producing the catalytically active layer on the zeolite foam was carried out in the same manner as in Example 1, except that the obtained material was calcined at 550 ° C for 10 hours.

Example 4

The process for producing the catalytically active layer on the zeolite foam is carried out in the same manner as in Example 1, except that particles or crumb of alkali-activated zeolite foam are used instead of pellets.

Industrial applicability

The process for the production of a catalytically active layer on zeolite foam is industrially applicable in the production of heterogeneous catalysts, catalyst supports and sorption materials for gases and liquids.

Claims (5)

PATENT CLAIMS A process for producing a catalytically active layer on a zeolite foam, characterized in that the alkali-activated zeolite foam is immersed for 1 to 12 hours in a solution of at least one inorganic salt with a concentration of 0.05 to 1 mol / dm ³ at a temperature of 25 to 100 ° C, in which it is allowed to react for 1 to 10 hours, then the reacted zeolite foam is washed with demineralized water and then at least dried at 80 to 250 ° C for 4 to 12 hours to form a hydroxide layer on the zeolite foam. The production method according to claim 1, characterized in that the alkali-activated zeolite foam is in at least one form selected from the group consisting of pellets and crumb. Process for the preparation of any one of claims 1 and 2, characterized in that the at least one inorganic salt is at least one water-soluble salt containing cations selected from the group consisting of Ag ⁺ , Cu ²⁺ , ZrO ²⁺ , Co ²⁺ , Ni cations ²⁺ , Zn ²⁺ , Mn ²⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Fe ³⁺ , Ga ³⁺ , In ³⁺ , Cr ³ +, Y 'Sn ⁴ . Ce ⁴⁺ and trivalent cations of lanthanides. Process according to any one of claims 1 to 3, characterized in that the at least one inorganic salt is at least one water-soluble salt selected from the group consisting of nitrates, sulfates and chlorides. The production method according to any one of claims 1 to 4, characterized in that the reacted zeolite foam is annealed at 300 to 600 ° C for 4 to 10 hours after drying to form an oxide layer on the zeolite foam.