WO2021031415A1 - Fenton fluidized bed catalyst and preparation method therefor - Google Patents

Abstract

Provided is a Fenton fluidized bed catalyst and a preparation method therefor. The preparation method of the catalyst comprises the following steps: S1. preparing an impregnation solution having an Fe²⁺ concentration of 0.8-1.5% and an Fe³⁺ concentration of 0.2-0.5% by using a divalent iron salt and a trivalent iron salt as raw materials; S2. immersing a matrix ball in the impregnation solution; S3. adding a 1 mol/L NaOH solution until pH <9 under stirring, and stirring same for 0.5 h; S4. aging same, wherein hydroxyl oxidized iron crystals are uniformly attached to the surface of the matrix ball; and S5. after the substrate ball with the hydroxyl oxidized iron crystals attached thereto is dried, sintering same at 100-350ºC for 4-5 h. The catalyst greatly reduces the usage amount of Fe²⁺ in a Fenton reagent, decreases the effect of Fe²⁺ on the COD of an effluent, greatly decreases the generated amount of iron sludge, and reduces the cost of solid waste treatments.

Description

Fenton fluidized bed catalyst and preparation method thereof Technical field

The invention relates to the technical field of water treatment, in particular to a Fenton fluidized bed catalyst and a preparation method thereof.

Background technique

Fenton is an advanced oxidation technology. In today's era of clean production, safety and environmental protection, sewage discharge standards in all walks of life are becoming stricter. Fenton oxidation, as a water treatment process, is getting more and more attention. The mechanism of the Fenton reaction is to use Fe ^{2+ to} catalyze the decomposition of H ₂ O _{2 to} produce OH·attack organic molecules to deprive hydrogen, degrade macromolecular organic matter into small molecular organic matter or mineralize it into _{inorganic matter such as CO 2} and H ₂ O, chemical reaction The equation is as follows:

Fe ²⁺ +H ₂ O ₂ →Fe ³⁺ +OH ^－ +OH· (1)

R—H+OH·→R·+H ₂ O (2)

R·+Fe ³⁺ →R ⁺ +Fe ²⁺ (3)

The main parameters that affect the Fenton reagent reaction include the pH of the solution, residence time, temperature, hydrogen peroxide and Fe ²⁺ concentration. Fenton oxidation is widely used because it can oxidize and destroy a variety of toxic and harmful organic substances, the reaction conditions are mild, the equipment is simple, and it can be processed alone or combined with other methods. However, the Fenton reagent uses a large amount of reagents, and excessive ferrous iron will increase the COD value of the treated wastewater, and produce a large amount of iron sludge, which increases the cost of solid waste treatment.

Summary of the invention

The purpose of the present invention is to provide a Fenton fluidized bed catalyst and a preparation method thereof in view of the disadvantages of the existing Fenton reagent.

In order to achieve one of the above-mentioned purposes of the invention, the present invention adopts the following solutions:

A preparation method of Fenton fluidized bed catalyst includes the following methods: S1 uses divalent iron salt and trivalent iron salt as raw materials, and prepares Fe ²⁺ concentration of 0.8% to 1.5%, and Fe ³⁺ concentration of 0.2% to 0.5 % Dipping solution; S2 immersed the matrix ball in the dipping solution, the matrix ball includes activated alumina balls or ceramsite; S3 under stirring, add 1mol/L lye to adjust 7＜pH＜9, and stir for 0.5h ; S4 aging, iron oxyhydroxide crystals are uniformly attached to the surface of the base ball; S5 after the base ball attached to the iron oxyhydroxide crystals is dried, sinter at 100℃～350℃ for 4h～5h.

A Fenton fluidized bed catalyst is prepared by the preparation method of Fenton fluidized bed catalyst described in any one of the above.

A Fenton fluidized bed catalyst includes a base ball, iron oxyhydroxide attached to the surface of the base ball, and the base ball includes activated alumina balls or ceramsite.

Compared with the prior art, the beneficial effects of the present invention are: the preparation method of the Fenton fluidized bed catalyst of the present application uses the base ball as the base, and the Fe ²⁺ and Fe ³⁺ in the immersion solution react with alkali to generate hydroxyl Iron oxide adheres to the micropores of the matrix ball; the formed Fenton fluidized bed catalyst greatly reduces the ^{amount of Fe 2+} in the Fenton reagent, reduces the influence of Fe ²⁺ on the COD of the effluent, and greatly reduces the iron The amount of mud produced reduces the cost of solid waste treatment.

detailed description

The application will be described in detail below in conjunction with specific implementations. However, these embodiments do not limit the application, and the structural, method, or functional changes made by those of ordinary skill in the art according to these embodiments are all included in the protection scope of the application.

This application provides a method for preparing a Fenton fluidized bed catalyst, including

S1 uses divalent iron salt and trivalent iron salt as raw materials to prepare ^{an impregnation solution with Fe 2+} concentration of 0.8% to 1.5% and Fe ³⁺ concentration of 0.2% to 0.5%;

S2 immerse the base ball in the dipping solution, the base ball including activated alumina ball or ceramsite;

S3 slowly add 1 mol/L lye under stirring to adjust 7<pH<9, and stir for 0.5h; the lye is selected from but not limited to NaOH solution, KOH solution, Na ₂ CO ₃ , (NH ₄ ) ₂ CO ₃ and the like.

S4 aging, the iron oxyhydroxide crystals are uniformly attached to the surface of the base ball; the uniformity here means that the distribution concentration of iron oxyhydroxide in each area is within a narrow range, which is not strictly uniform. distributed;

S5 After the base ball with iron oxyhydroxide crystals is dried, it is sintered at 100℃～350℃ for 4h～5h.

Wherein, in step S1, the divalent iron salt can be selected from but not limited to FeSO ₄ , and the trivalent iron salt can be selected from but not limited to Fe ₂ (NO ₃ ) ₃ . In step S2, the activated alumina balls are γ-Al ₂ O ₃ balls purchased from any manufacturer on the market, and the particle size of the activated alumina balls is 3 mm to 5 mm, or the ceramsite is yellow clay particles. The particle size of the yellow clay particles is 3mm-5mm, and the matrix sphere has a suitable specific surface area, and after adsorbing the catalyst, a catalyst suitable for a Fenton fluidized bed is formed.

In addition, the volume ratio of the base ball to the impregnation solution is 1:1 to 2:1, which ensures that a sufficient amount of catalyst can be formed on the surface of the activated alumina in step S3.

In step S3, the divalent iron and trivalent iron in the immersion solution react with alkali to form iron oxyhydroxide, which is attached to the micropores of the matrix ball, and the formed iron oxyhydroxide crystal phase is mainly α-FeOOH and γ-FeOOH mixture.

In step S4, the aging process includes stirring once every half an hour for the first 3 hours to 5 hours, each time for 5 minutes; and then aging for at least 24 hours in an environment of 20°C to 50°C.

In a specific preparation method, FeSO ₄ and Fe ₂ (NO ₃ ) _{3 are used} as raw materials to prepare ^{an immersion solution with Fe 2+} of 0.8% to 1.5% and Fe ³⁺ of 0.2% to 0.5%; the matrix ball is immersed in the In the dipping solution, slowly add 1mol/L NaOH solution to pH>9 under stirring conditions, stir for 0.5h, stir once every half an hour for the first 3h～5h, 5min each time; then age at 20℃-50℃ At least 24h; the iron oxyhydroxide crystals are uniformly attached to the surface layer of the base ball, and after drying, the Fenton fluidized bed catalyst is obtained by sintering at 100℃～350℃ for 4h～5h.

This application also provides a Fenton fluidized bed catalyst obtained by any of the above methods,

Of course, the Fenton fluidized bed catalyst of the present application can also be obtained by other methods, which includes matrix balls, iron oxyhydroxide attached to the surface of the matrix balls, and the matrix balls include activated alumina balls or ceramsites. The activated alumina ball base ball is a γ-Al ₂ O ₃ ball, and the base ball has a particle size of 3 mm to 5 mm; or the ceramsite is a yellow clay particle, and the yellow clay particle has a particle size of 3 mm to 3 mm. 5mm, the iron oxyhydroxide is a mixture of α-FeOOH and γ-FeOOH.

The above-mentioned Fenton fluidized bed catalyst greatly reduces the ^{amount of Fe 2+} used in the Fenton reagent, reduces the influence of Fe ²⁺ on the COD of the effluent, and greatly reduces the amount of iron sludge produced and reduces the cost of solid waste treatment.

To sum up, the preparation method of the Fenton fluidized bed catalyst of the present application uses the matrix ball as the matrix, and the Fe ²⁺ and Fe ³⁺ in the immersion solution react with alkali to form iron oxyhydroxide attached to the matrix ball. The Fenton fluidized bed catalyst formed in the micropores greatly reduces the ^{amount of Fe 2+} used in the Fenton reagent, reduces the impact of Fe ²⁺ on the COD of the effluent, and greatly reduces the amount of iron sludge produced and reduces solid waste Processing costs.

It should be understood that although this specification is described in accordance with the implementation manners, not each implementation manner only includes an independent technical solution. This narration in the specification is only for clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions of feasible implementations of the present invention, and are not intended to limit the scope of protection of the present invention. Any equivalent implementations or changes made without departing from the technical spirit of the present invention All should be included in the protection scope of the present invention.

Claims (13)

1. A preparation method of Fenton fluidized bed catalyst includes the following methods:

   S1 uses divalent iron salt and trivalent iron salt as raw materials to prepare ^{an impregnation solution with Fe 2+} concentration of 0.8% to 1.5% and Fe ³⁺ concentration of 0.2% to 0.5%;

   S2 immerse the base ball in the dipping solution, the base ball is activated alumina ball or ceramsite;

   Under S3 stirring, add 1mol/L lye to adjust 7＜pH＜9, and stir for 0.5h;

   S4 aging, iron oxyhydroxide crystals are uniformly attached to the surface of the base ball;

   S5 After the base ball with iron oxyhydroxide crystals is dried, it is sintered at 100℃～350℃ for 4h～5h.
2. The method for preparing Fenton fluidized bed catalyst according to claim 1, characterized in that:

   The divalent iron salt is selected from FeSO ₄ , and/or the trivalent iron salt is selected from Fe ₂ (NO ₃ ) ₃ .
3. The method for preparing a Fenton fluidized bed catalyst according to claim 1, wherein the activated alumina balls are γ-Al ₂ O ₃ balls, and the particle size of the activated alumina balls is 3 mm to 5 mm.
4. The preparation method of the Fenton fluidized bed catalyst according to claim 1, wherein the ceramsite is yellow clay particles, and the particle size of the yellow clay particles is 3 mm-5 mm.
5. The method for preparing a Fenton fluidized bed catalyst according to claim 1, wherein in step S2, the volume ratio of the matrix ball to the impregnation solution is 1:1 to 2:1.
6. The preparation method of Fenton fluidized bed catalyst according to claim 1, characterized in that, in step S3, Fe ²⁺ and Fe ³⁺ in the immersion solution react with alkali to form iron oxyhydroxide, which is attached to the base ball Micropores.
7. The method for preparing Fenton fluidized bed catalyst according to claim 6, wherein the iron oxyhydroxide formed is a mixture of α-FeOOH and γ-FeOOH.
8. The method for preparing a Fenton fluidized bed catalyst according to claim 1, wherein the aging process includes: stirring once every half an hour for the first 3h to 5h, each time for 5 minutes; and then aging at 20°C to 50°C. For at least 24h.
9. A Fenton fluidized bed catalyst characterized in that it is prepared by the method for preparing the Fenton fluidized bed catalyst according to claim 1.
10. A Fenton fluidized bed catalyst is characterized by comprising matrix balls, iron oxyhydroxide attached to the surface of the matrix balls, and the matrix balls are activated alumina balls or ceramsites.
11. The Fenton fluidized bed catalyst according to claim 10, wherein the activated alumina balls are γ-Al ₂ O ₃ balls, and the particle size of the activated alumina balls is 3 mm to 5 mm.
12. The Fenton fluidized bed catalyst according to claim 10, wherein the ceramsite is yellow clay particles, and the particle size of the yellow clay particles is 3 mm to 5 mm.
13. The Fenton fluidized bed catalyst of claim 10, wherein the iron oxyhydroxide is a mixture of α-FeOOH and γ-FeOOH.