CN105883847A - Preparation method of iron-containing Y-shaped zeolite - Google Patents

Abstract

The invention belongs to the field of preparation of heteroatom-modified microporous zeolite, and in particular relates to a preparation method of iron oxide-loaded modified Y-type zeolite. The method is specifically as follows: first, fully mix and age silicon source, aluminum source, sodium hydroxide, and water to prepare a directing agent solution; mix sodium metaaluminate, sodium hydroxide, water and the directing agent solution evenly to form an initial gel , adding ferric nitrate directly to it, and suction-filtering the iron-containing hydrogel to obtain a semi-dry solid, which is crystallized under hydrothermal conditions, and the solid is washed, filtered, dried, and roasted to obtain the product. Through the present invention, Fe ³⁺ is directly introduced into the initial gel synthesized by Y-type zeolite, which can avoid post-treatment steps such as impregnation and ion exchange, and is easy to operate; the method of first draining and recrystallizing can greatly reduce the amount of synthesis by traditional techniques. The water content in the hydrothermal treatment process of the zeolite material can increase the yield of single-pot molecular sieves. This process can improve energy efficiency, save production costs, and has industrial practical value.

Description

A kind of preparation method of iron-containing Y-type zeolite

technical field

The invention belongs to the field of preparation of heteroatom-modified microporous zeolite, and in particular relates to a preparation method of iron oxide-loaded modified Y-type zeolite.

Background technique

With the rapid development of petrochemical, metallurgy, printing and dyeing industries, a large amount of industrial wastewater containing refractory organic pollutants has been produced, which has become one of the main sources of water environmental pollution. For the removal of high-concentration refractory organic pollutants, understand a major problem in the current water treatment field.

Using homogeneous catalysts (such as Fenton's reagent, ferrous salt, etc. ₎ to catalyze the oxidation of H2O2 can degrade organic _pollutants to _CO2 and _H2O , so the deep oxidation of organic pollutants can be degraded and mineralized by hydroxyl radicals Technology gets a lot of attention. However, the homogeneous catalyst used in this method is difficult to separate from the reaction medium, which brings problems such as loss of active components and secondary pollution. The use of heterogeneous solid catalysts instead of homogeneous iron salts can overcome the shortcomings of the homogeneous method, and has become a current research hotspot.

Zeolite molecular sieves are a very important class of inorganic porous materials, with high thermal and hydrothermal stability, large specific surface area, good ion exchange performance, and pore structure with molecular size (usually 0.3-2.0nm). , are widely used in many industrial fields, such as shape-selective catalysts, adsorbents, ion exchangers, etc. Loading iron oxides in the zeolite structure to make iron-containing zeolite heterogeneous catalysts is used to catalyze the degradation of organic pollutants (such as phenol, dye wastewater), and has a good degradation effect. However, in the traditional zeolite synthesis process, the silicon source, the aluminum source and the alkali source solution are fully mixed to form an initial gel, and the initial gel is hydrothermally reacted and crystallized to obtain a solid. Iron doping methods include impregnation method, ion exchange method, co-precipitation method, etc., all of which use iron salt solution to post-treat zeolite raw materials, involving many operating steps, which are not conducive to industrial implementation and cost reduction. The introduction of iron species into the initial gel of zeolite synthesis, followed by crystallization, can simplify the synthesis steps.

In addition, in the hydrothermal reaction process of crystal growth, a large amount of water is used as a solvent, and most of the volume in the kettle is occupied by solvent water, which makes the output of a single kettle limited and consumes a lot of energy. If the water content in the hydrothermal reaction process can be reduced, the solid content in the single kettle can be increased, the yield of molecular sieve in the single kettle can be increased, energy consumption can be reduced, and cost can be saved. For industrial production, the reduction of production costs means the improvement of economic benefits. At the same time, low energy consumption is also a requirement for green environmental protection.

Contents of the invention

The present invention aims to provide a preparation method of iron-containing Y-type zeolite, which directly introduces ^Fe into the initial gel of Y-type zeolite synthesis, avoids post-treatment steps such as impregnation and ion exchange, and adopts iron-containing The initial gel is drained and then crystallized at high temperature to reduce the water content in the hydrothermal reaction process and increase the single-pot yield of the iron-containing molecular sieve. This technology is simple in process, easy to operate, and convenient for industrial implementation. Concrete technical scheme of the present invention is:

1) Preparation of directing agent

Water glass, sodium metaaluminate, sodium hydroxide and water are thoroughly mixed to form a clear and transparent solution, which is aged at room temperature for 24 to 60 hours to obtain the directing agent solution. In the directing agent solution, the molar ratio of the added amount of each reaction raw material is: Na ₂ O/Al ₂ O ₃ /SiO ₂ /H ₂ O=12˜20/1/19/300˜400.

2) Preparation of initial gel

Mix a certain amount of sodium metaaluminate, sodium hydroxide and water, slowly add the above-mentioned directing agent dropwise, and stir thoroughly for 15-60 minutes to form an initial gel. The molar ratio of each component is: Na ₂ O/Al ₂ O ₃ /SiO ₂ /H ₂ O=3.2～4.5/1/3/120～180;

3) Incorporation of iron

Slowly add a certain amount of iron salt (Fe(NO ₃ ) ₃ 9H ₂ O) to the above initial gel, so that the molar ratio of Fe ₂ O ₃ to SiO ₂ in the initial gel is 0.1-1.0:3, and continue stirring for 30 ~60 minutes to obtain iron-containing hydrogel;

4) Drying and crystallization to synthesize iron-containing Y-type zeolite

Suction filter the above-mentioned iron-containing hydrogel until there is no liquid dripping, and the obtained semi-dry solid undergoes a hydrothermal reaction at 80-100°C, and stands to crystallize for 18-24 hours;

5) Filtration, washing, drying, roasting

After the crystallization is completed, the obtained product is washed, suction-filtered, and dried at 80° C. for more than 20 hours. After the drying is completed, the product is baked in a muffle furnace at 550°C for 5 hours

Beneficial effects: the synthesis method of iron-containing Y-type zeolite provided by the present invention, because Fe ³⁺ is directly introduced into the initial gel synthesized by Y-type zeolite, avoids the steps of impregnation, ion exchange and other post-treatments to introduce iron, and is easy to operate ;The method of draining the iron-containing initial gel and then carrying out high-temperature crystallization can greatly reduce the water content in the traditional hydrothermal treatment process, and increase the solid content of the iron-containing molecular sieve in the single kettle. This process can improve energy efficiency , saving production cost, has huge industrial practical value and application prospect.

detailed description

The following are specific embodiments of the present invention, which are further descriptions of the present invention. However, the specific embodiments do not limit the claims of the present invention.

The raw material used in the specific embodiment is as follows:

Water glass: produced by Tianjin Jinnan Juxing Soda Soda Factory, wherein the mass fraction of silicon oxide is 20.3%;

Sodium metaaluminate: produced by Tianjin Guangfu Fine Chemical Research Institute;

Sodium hydroxide: produced by Tianjin Beifang Tianyi Chemical Reagent Factory.

Example 1:

Preparation of guiding agent: Dissolve 0.7 g of sodium metaaluminate in 10.0 ml of water, add 3 g of sodium hydroxide, stir until clear, add 22.5 g of water glass dropwise, and stir mechanically for about 30 minutes to obtain a clear and transparent solution. Standing and aging at room temperature for 24 hours, the directing agent was obtained.

Preparation of iron-containing Y-type zeolite: Dissolve 3.5 grams of sodium metaaluminate in 38.5 milliliters of water, add 41.5 grams of water glass, stir evenly, slowly add 33.5 grams of directing agent solution to it, stir mechanically for about 30 minutes, and mix well To obtain the initial gel, add 1.2 g of ferric nitrate nonahydrate to it, and continue to stir for 60 minutes. The obtained gel is suction-filtered until there is no more liquid dripping. After standing for 24 hours to react, the obtained product was washed, suction filtered, and dried at 80°C for 20 hours. After drying, the product was roasted in a muffle furnace at 550°C for 5 hours to obtain the final product.

Example 2:

Preparation of guiding agent: Dissolve 0.7 g of sodium metaaluminate in 10.0 ml of water, add 3 g of sodium hydroxide, stir until clear, add 22.5 g of water glass dropwise, and stir mechanically for about 30 minutes to obtain a clear and transparent solution. Standing and aging at room temperature for 40 hours, the directing agent was obtained.

Preparation of iron-containing Y-type zeolite: Dissolve 2.4 grams of sodium metaaluminate in 26 milliliters of water, add 30 grams of water glass, mix well, slowly add 16 grams of directing agent solution to it, stir mechanically for about 30 minutes, and mix well To obtain the initial gel, add 2.5 grams of ferric nitrate nonahydrate to it, continue to stir for 60 minutes, filter the obtained gel with suction, until no more liquid drips, put the semi-dry solid into the reaction kettle, and heat it at 100°C After standing for 24 hours to react, the obtained product was washed, suction filtered, and dried at 80°C for 20 hours. After drying, the product was roasted in a muffle furnace at 550°C for 5 hours to obtain the final product.

Example 3:

Preparation of guiding agent: Dissolve 0.7 g of sodium metaaluminate in 10.0 ml of water, add 3 g of sodium hydroxide, stir until clear, add 22.5 g of water glass dropwise, and stir mechanically for about 30 minutes to obtain a clear and transparent solution. Standing and aging at room temperature for 24 hours, the directing agent was obtained.

Preparation of iron-containing Y-type zeolite: Dissolve 3.2 grams of sodium metaaluminate in 37 milliliters of water, add 1.6 grams of sodium hydroxide and 47.2 grams of water glass, mix well, slowly add 4 grams of directing agent solution dropwise, and mechanically stir for about After 30 minutes, mix evenly to obtain the initial gel, add 3.6 grams of ferric nitrate nonahydrate to it, continue to stir for 60 minutes, filter the obtained gel until there is no more liquid dripping, put the semi-dry solid into the reaction In the kettle, stand at 100°C for 24 hours, the obtained product is washed, filtered, and dried at 80°C for 20 hours. After drying, the product is baked in a muffle furnace at 550°C for 5 hours to obtain the final product .

The above are only several implementation examples of the present invention, and are not intended to limit the present invention in any form. Any skilled person who is familiar with the profession can use the structure disclosed above and Equivalent implementation cases with minor changes or modifications to equivalent changes in technical content. However, any simple modifications, equivalent changes and modifications made to the above implementation cases according to the technical essence of the present invention are still within the scope of the technical solutions of the present invention.

Claims (7)

1. a preparation method of iron-containing Y type zeolite, is characterized in that, specifically comprises the following steps: 1) Preparation of directing agent First, fully mix the silicon source, aluminum source, alkali source and water according to a certain ratio, and leave to age at room temperature for 24 to 60 hours to obtain the required directing agent; 2) Preparation of initial gel Mix a certain amount of silicon source, aluminum source, alkali source and water, slowly add the above-mentioned directing agent dropwise, and stir thoroughly for 15-60 minutes to obtain the initial gel; 3) Incorporation of iron Slowly add a certain amount of iron salt to the above initial gel, and continue stirring for 30 to 60 minutes to obtain an iron-containing hydrogel; 4) Synthesis of iron-containing Y-type zeolite by draining and crystallization The above-mentioned iron-containing hydrogel is suction-filtered until no liquid drops, and the semi-dry solid obtained by suction filtration is subjected to a hydrothermal reaction at 80-100°C, and left to stand for crystallization for 18-24 hours; 5) Filtration, washing, drying, roasting After the crystallization is completed, the obtained product is washed, suction-filtered, and dried at 80°C for more than 20 hours. After drying, the product is baked in a muffle furnace at 550°C for 5 hours. 2. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the silicon source used in the synthesis is water glass. 3. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the aluminum source used in the synthesis is sodium metaaluminate. 4. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the alkali source used in the synthesis is sodium hydroxide. 5. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the water used in the synthesis is deionized water. 6. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the addition amount of each reaction raw material should make the molar ratio of each composition in the directing agent be: in Na ₂ O/Al ₂ O ₃ /SiO ₂ /H ₂ O=12-20/1/19/300-400. 7. the preparation method of iron-containing Y-type zeolite according to claim 1 is characterized in that, the addition amount of each reaction raw material should make the molar ratio of each composition in the initial gel be: Fe ₂ O ₃ /Na ₂ O/Al ₂ O ₃ /SiO ₂ /H ₂ O=0.1-1.0/3.2-4.5/1/3/120-180.