An iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material, a preparation method thereof, and an application thereof
By converting sewage sludge ash into a load iron sodalite catalyst through melting and hydrothermal processing, the method addresses the limited utilization of SSA components, enabling efficient recovery and high-value applications in water treatment.
Patent Information
- Application Number
- CN202311232751.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-22
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2043-09-22
AI Technical Summary
In the prior art, the added value of the resource utilization of sludge incineration (SSA) produced by sludge incineration is limited, and it is difficult to effectively utilize its inorganic components, especially SiO2, Al2O3 and Fe2O3, and the proportion of traditional methods in building materials is low.
The iron-carried soda catalyst is prepared by melt-hydrothermal-impregnation method. Activated sludge incineration ash is used as raw material, and iron-carried soda catalyst is formed by loading ferrous on soda crystals, which is used to degrade organic pollutants in water environments like Fenton.
The efficient recycling and resource utilization of silicon, aluminum and iron in activated sludge incineration ash was achieved, the treatment methods of sludge incineration by-products were expanded, the added value of SSA products was increased, and the efficient and deep degradation of a variety of organic pollutants was achieved in Fenton-like reactions.
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Abstract
Description
Technical Field
[0001] The invention relates to an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material, a preparation method and application thereof, and belongs to the technical field of comprehensive utilization of solid waste and water treatment. Background Art
[0002] With the growth of population and the advancement of urbanization, the operating pressure of sewage treatment plants has increased, and the output of residual activated sludge has also increased year by year. It is reported that China's residual sludge production in 2020 has exceeded 60 million tons. The harmless and resource-based treatment of residual sludge has become an urgent problem to be solved in the field of environment. At present, incineration is one of the main methods of sludge treatment. Although it can achieve efficient reduction of sludge, about 30% of inorganic solid components still remain in the form of sludge ash (Sewage Sludge Ash, SSA). In view of the huge amount of SSA produced by sludge incineration each year, it is of scientific and practical significance to further develop the use of SSA and increase the added value of SSA-based products.
[0003] At present, the conventional way to recycle SSA is to use it as a raw material or additive for building materials. For example, SiO2 in SSA can be used as a raw material for the synthesis of cement, and SiO2, Al2O3 and Fe2O3 in SSA can be used to prepare building bricks. However, the added value of this method is limited, and due to the variable inorganic components and content in SSA, its application in building materials is relatively low. In recent years, the selective use of inherent elements in SSA to synthesize high value-added compounds has been a development trend in the resource utilization of SSA. Representative cases include the recovery of phosphorus in SSA to prepare phosphate fertilizers and the use of silicon and aluminum in SSA to prepare modified adsorbents.
[0004] Therefore, further promoting the preparation of functional materials using SSA as raw materials is of great significance to the resource treatment and value-added of sludge and SSA. Summary of the invention
[0005] In order to solve the above technical problems, the present invention provides an iron-loaded sodalite catalyst using activated sludge incineration ash as raw material, and a preparation method and application thereof.
[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0007] The present invention provides a method for preparing an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material, comprising the following steps: S1. Using activated sludge incineration ash as a raw material, obtaining sodalite crystals and iron sludge residues through melting-filtration-hydrothermal treatment; S2. Utilizing the iron sludge residues, obtaining a ferrous solution through dissolution-reduction treatment; S3. Placing the sodalite crystals in the ferrous solution, and loading ferrous onto the sodalite crystals through impregnation treatment to obtain an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material.
[0008] Preferably, step S1 is specifically as follows: Mixing activated sludge incineration ash with an alkali reagent, placing it in a muffle furnace for calcination and melting treatment to obtain a melt; Dissolving the melt in an alkali solution prepared with the same alkali reagent and stirring until fully dissolved, filtering to obtain the clarified solution and the iron sludge residues; Conducting hydrothermal treatment on the clarified solution and recovering the crystallization product, washing and drying the crystallization product to obtain the sodalite crystals.
[0009] Preferably, in step S1, the mass ratio of the alkali reagent to the activated sludge incineration ash is 0.8 to 1.2; the alkali reagent is one or more of KOH, NaOH, Na2CO3, and NaHCO3; the specific parameters of the calcination and melting treatment are a constant temperature of 400 to 600 °C and calcination for 90 min; the specific parameters for dissolving the melt in the alkali solution and stirring until fully dissolved are an alkali concentration of 1 to 3 M, a solid-liquid ratio of 0.1 to 0.4, and a stirring time of 3 h; the specific parameters of the hydrothermal treatment are 70 to 110 °C and 4 to 16 h.
[0010] Preferably, step S2 is specifically as follows: After acid-leaching the iron sludge residues with a hydrochloric acid solution, filtering to remove insoluble substances, and adding a reducing agent to obtain the ferrous solution.
[0011] Preferably, in step S2, the specific parameters of the acid-leaching treatment are that the concentration of the hydrochloric acid solution is 1 to 10 M and the impregnation time is 4 to 12 h; the reducing agent is one or more of sodium sulfite, hydroxylamine hydrochloride, and ascorbic acid.
[0012] Preferably, step S3 is specifically as follows: After impregnating the sodalite crystals in the ferrous solution, filtering and freeze-drying are sequentially performed to obtain the iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material.
[0013] Preferably, in step S3, the impregnation treatment time is 6 to 24 h.
[0014] The present invention also provides an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material, which is prepared by the method for preparing an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material as described above.
[0015] The present invention also provides the application of the iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material in the field of Fenton-like catalysis as described above.
[0016] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:
[0017] (1) The present invention realizes the efficient recovery and resource utilization of silicon, aluminum, and iron in activated sludge incineration ash, expands the treatment methods of sludge incineration by-products, and provides a basis for the development of inorganic functional materials.
[0018] (2) The product prepared by the present invention can be used to catalyze the Fenton-like reaction to achieve the efficient and deep degradation of various organic pollutants in the water environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] One or more embodiments are illustrated by way of example in the accompanying drawings, and these illustrative descriptions do not limit the embodiments. Unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limitation.
[0020] Figure 1 FIG. is a preparation flow chart of an iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material according to an embodiment of the present invention;
[0021] Figure 2 FIG. is an X-ray diffraction spectrogram of an iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material according to an embodiment of the present invention;
[0022] Figure 3 FIG. is a scanning electron micrograph of an iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material according to an embodiment of the present invention;
[0023] Figure 4 FIG. is a degradation effect diagram of methylene blue by an iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material in different reaction systems according to an embodiment of the present invention;
[0024] Figure 5 FIG. is a degradation effect diagram of sulfamethoxazole by an iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material in different reaction systems according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] The inventors found that the Fenton system is widely used in the treatment of refractory organic pollutants due to its high degradation efficiency. In this system, the oxidant is Fe 2+Catalytic decomposition generates strongly oxidizing free radicals, which non-selectively mineralize or decompose organic compounds, ultimately producing harmless products such as CO2, H2O, or inorganic salts. However, the classical Fenton system has limitations such as a narrow reaction pH range, particle aggregation, and high sludge production. To overcome these drawbacks, researchers have developed heterogeneous Fenton-like catalysts, such as the most common iron-based catalysts. Iron-based catalysts are composed of iron and porous materials. Sodalite is a porous material with a cage-like structure composed of tetrahedra [SiO4] 4- and [AlO4] 4- and is an excellent carrier for heterogeneous Fenton-like catalysts. Given the unique composition and surface properties of sodalite, the prepared iron-loaded sodalite catalyst can concentrate pollutants near the catalytic active centers through adsorption, and the high concentration of ferrous ions on its surface can significantly improve the catalytic-degradation efficiency while avoiding the generation of iron sludge, so it has received wide attention in practical water treatment.
[0026] Innovatively, this invention uses SSA as the raw material and prepares the iron-loaded sodalite catalyst by the melting-hydrothermal-impregnation method without adding extra silicon, aluminum, and iron sources, and applies it to the Fenton-like system to degrade organic pollutants in the water environment. This invention provides a new solution for developing a new method for the resource disposal of SSA and improving the added value of SSA products.
[0027] It should be specifically noted that the following examples are only used to help explain this invention and do not constitute a limitation to this invention. Those skilled in the art can make modifications, changes, and substitutions in the following examples. Any other corresponding changes and deformations made by the technical concept of this invention should be included within the protection scope of the claims of this invention.
[0028] The preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material provided by the embodiments of this invention will be described in detail below.
[0029] Figure 1 is a flowchart of the preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material according to an embodiment of this invention.
[0030] As Figure 1 shown, the preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as the raw material provided by the embodiments of this invention includes the following steps
[0031] S1. Using activated sludge incineration ash as the raw material, obtain sodalite crystals and iron sludge residues by melting-hydrothermal treatment;
[0032] Specific steps of step S1: Mix the incineration ash after sludge incineration treatment with an alkali, and place it in a muffle furnace for melting treatment; dissolve the obtained melt in an alkali solution and stir, filter to obtain iron mud residue and solution, perform hydrothermal treatment on the solution and recover the crystallization product. Wash and dry the crystallization product to obtain sodalite crystals. The incineration ash is mixed with an alkali, and the mass ratio of the alkali to the incineration ash is 0.8 - 1.2; the alkali reagent is one or more of KOH, NaOH, Na2CO3, and NaHCO3; it is placed in a muffle furnace for calcination, and calcined at a constant temperature of 400 - 600 °C for 90 min; the melt is dissolved in an alkali solution and stirred, the alkali concentration is 1 - 3 M, the solid-liquid ratio is 0.1 - 0.4, and the stirring time is 3 h; the solution is subjected to hydrothermal treatment, and the hydrothermal treatment conditions are 70 - 110 °C for 4 - 16 h.
[0033] S2. Acid leaching - reduction treatment of iron mud residue to obtain ferrous solution;
[0034] Specific steps of step S2: After acid leaching treatment of iron mud residue, filter to obtain a solution, and add a reducing agent to the solution to obtain a ferrous solution. The acid leaching conditions are that the hydrochloric acid concentration is 10 M for 12 h; the reducing agent is one or more of sodium sulfite, sodium persulfate, and hydroxylamine hydrochloride.
[0035] S3. Load ferrous ions on sodalite crystals through impregnation treatment to obtain an iron - loaded sodalite catalyst using activated sludge incineration ash as raw material.
[0036] Specific steps of step S3: Place the prepared sodalite crystals in the ferrous solution for impregnation. After a period of time, filter and freeze - dry in sequence to obtain an iron - loaded sodalite catalyst using activated sludge incineration ash as raw material.
[0037] The iron - loaded sodalite catalyst prepared by the above - mentioned preparation method using activated sludge incineration ash as raw material is applied to the field of Fenton - like catalysis.
[0038] The catalytic performance of the iron - loaded sodalite catalyst using activated sludge incineration ash as raw material is described below by taking methylene blue and sulfamethoxazole as target pollutants as examples, and the same can be obtained for other target pollutants.
[0039] Example 1
[0040] 1) Preparation of sodalite crystals
[0041] Mix the sludge incineration ash with NaOH reagent, and place it in a muffle furnace for calcination at 550 °C to obtain a molten mixture. Dissolve the molten mixture in 2 M NaOH solution at room temperature, stir magnetically for 3 h, filter to obtain iron mud residue and supernatant. Hydrothermally crystallize the obtained supernatant at 90 °C for 12 h, wash the crystallization product with water, and dry it in an oven overnight to obtain sodalite crystals.
[0042] 2) Preparation of Iron-Loaded Sodalite Catalyst
[0043] The recycled iron sludge was fully dissolved in dilute hydrochloric acid solution and filtered to remove insoluble substances. Hydroxylamine hydrochloride reagent was added to the solution, and the prepared sodalite crystals were immersed in the solution for 12 h. The iron-loaded sodalite catalyst (Fe@Sodalite) was obtained after freeze-drying the impregnated sodalite. An Fe 2+ solution with the same concentration was prepared using ferrous sulfate reagent, and the impregnation and freeze-drying processes were repeated to obtain the iron-loaded sodalite catalyst (Reagent Fe@Sodalite) prepared from the reagent as the control group.
[0044] 2) Catalyst Characterization
[0045] The X-ray diffraction spectra of sodalite, Fe@Sodalite, and Reagent Fe@Sodalite are shown as Figure 2 follows. It can be seen that the diffraction peaks of the prepared sodalite correspond to 2θ = 13.9°, 24.2°, 31.4°, 34.6°, 37.4°, 40.0°, 52.3°, 56.5°, 58.5°, 62.4°, 64.4°, 69.9°, 75.3°, 77.9°, which are consistent with the sodalite card PDF#82-0517. Some diffraction peaks of Reagent Fe@Sodalite and Fe@Sodalite disappeared, and the intensity of the remaining diffraction peaks decreased, indicating that Fe 2+ was successfully loaded on the surface of sodalite and the crystal structure of sodalite was damaged. Field emission scanning electron microscopy was used to analyze the surface morphology of the samples. As Figure 3 shown in (a) and (b) therein, the prepared sodalite was spherical with a smooth surface. After modification with Fe 2+ solution, the morphology changed significantly. As Figure 3 shown in (c) and (d) therein, the surface was uneven and there were obvious loaded particles.
[0046] 4) Fenton-Like Catalytic Degradation of Methylene Blue
[0047] All experiments were carried out in a 100 ml beaker equipped with a magnetic stirrer at room temperature. Specifically, in each experiment, 0.015 mmol of peracetic acid was added to 50 ml of methylene blue (40 mg / L) solution, and then HCl (0.1 M) and NaOH solution (0.1 M) were added to adjust to the required initial pH value. Finally, 0.015 g of sodalite or Fe@Sodalite or Reagent Fe@Sodalite was added. 0.5 ml of the reaction solution was extracted with a syringe containing a 0.22 μm filter membrane at the selected reaction time, and immediately 0.5 ml of methanol was added to the reaction solution. All experiments were repeated and the average value was taken.
[0048] 5) Degradation of methylene blue in different systems
[0049] The degradation performance of methylene blue by individual oxidants, catalysts and different catalytic-oxidation systems within 20 min was investigated. As Figure 4 shown, although peracetic acid oxidant has a relatively high oxidation potential, the individual peracetic acid system could only remove 14.3% of methylene blue at 20 min, indicating that methylene blue is difficult to be directly oxidized and removed by peracetic acid. The ReagentFe@Sodalite system and Fe@Sodalite system could not achieve the oxidation and removal of methylene blue, and the limited methylene blue removal rate within this system was contributed by the adsorption performance of the material itself. The Reagent Fe@Sodalite / peracetic acid system and Fe@Sodalite / peracetic acid system achieved complete removal of methylene blue, indicating that iron-loaded sodalite could catalyze peracetic acid to exert a stronger oxidation effect and achieve efficient removal of methylene blue.
[0050] Example 2
[0051] All experiments on Fenton-like catalytic degradation of dexamethasone were carried out at room temperature in a 100 ml beaker equipped with a magnetic stirrer. Specifically, in each experiment, 0.035 mmol of peracetic acid was added to 50 ml of dexamethasone (10 mg / L) solution, and then HCl (0.1 M) and NaOH solution (0.1 M) were added to adjust to the desired initial pH value. Finally, 0.035 g of sodalite or Fe@Sodalite or Reagent Fe@Sodalite was added. 0.5 ml of the reaction solution was extracted with a syringe containing a 0.22 μm filter membrane at the selected reaction time, and immediately 0.5 ml of methanol was added to the reaction solution. All experiments were repeated and the average value was taken.
[0052] Degradation of dexamethasone in different systems
[0053] The degradation performance of dexamethasone by individual oxidants, catalysts and different catalytic-oxidation systems within 20 min was explored. As Figure 5As shown, the individual peracetic acid system can only remove 4.7% of dexamethasone at 20 min, indicating that it is difficult for peracetic acid to directly oxidize and remove dexamethasone. Reagent Fe@Sodalite and the Fe@Sodalite system also remove some dexamethasone due to their own adsorption characteristics. The Reagent Fe@Sodalite / peracetic acid system can only achieve a 19.6% removal of dexamethasone, while Fe@Sodalite / peracetic acid can achieve a 99.5% removal of dexamethasone, indicating that the iron-loaded sodalite prepared from the recovered iron element in sludge incineration ash has better peracetic acid activity performance than the iron-loaded sodalite prepared from reagent iron and can achieve efficient removal of dexamethasone.
[0054] The above embodiments use sludge incineration ash as raw material and prepare a series of iron-loaded sodalite catalysts with different iron contents through the melting-hydrothermal-impregnation method, and can achieve the following technical effects:
[0055] 1. Prepare sodalite crystals using sludge incineration ash as raw material and prepare iron-loaded sodalite catalysts with different ferrous ion contents by regulating the ferrous ion concentration.
[0056] 2. The prepared iron-loaded sodalite has good catalytic activity and can achieve efficient degradation of methylene blue and dexamethasone pollutants.
[0057] The above are only the embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A preparation method of an iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material, characterized in that, It includes the following steps: S1. Using the incinerated ash of activated sludge as raw material, obtain sodalite crystals and iron mud residues through melting - filtration - hydrothermal treatment. The specific steps of S1 are as follows: Mix the incinerated ash of activated sludge with an alkali reagent, place it in a muffle furnace for calcination and melting treatment to obtain a melt; dissolve the melt in an alkali solution prepared with the same alkali reagent and stir until fully dissolved, filter to obtain a clear solution and the iron mud residues; perform hydrothermal treatment on the clear solution and recover the crystalline product, wash and dry the crystalline product to obtain the sodalite crystals. S2. Using the iron mud residues, obtain a ferrous solution through dissolution - reduction treatment. The dissolution specifically refers to performing acid leaching treatment on the iron mud residues. S3. Place the sodalite crystals in the ferrous solution, and load ferrous ions onto the sodalite crystals through impregnation treatment to obtain an iron - loaded sodalite catalyst using the incinerated ash of activated sludge as raw material. The specific steps of S3 are as follows: After placing the sodalite crystals in the ferrous solution for impregnation treatment, filter and then perform freeze - drying treatment in sequence to obtain the iron - loaded sodalite catalyst using the incinerated ash of activated sludge as raw material.
2. The preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material according to claim 1, characterized in that, In the step S1, the mass ratio of the alkali reagent to the incinerated ash of activated sludge is 0.8 - 1.
2. The alkali reagent is one or more of KOH, NaOH, Na2CO3, and NaHCO3. The specific parameters of the calcination and melting treatment are a constant temperature of 400 - 600 °C and calcination for 90 min. The specific parameters for dissolving the melt in the alkali solution and stirring until fully dissolved are an alkali concentration of 1 - 3 M, a solid - liquid ratio of 0.1 - 0.4, and a stirring time of 3 h. The specific parameters of the hydrothermal treatment are 70 - 110 °C and 4 - 16 h.
3. The preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material according to claim 1, characterized in that, The specific steps of S2 are as follows: After performing acid leaching treatment on the iron mud residues with a hydrochloric acid solution, filter to remove insoluble substances, and add a reducing agent to obtain the ferrous solution.
4. The preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as raw material according to claim 3, characterized in that, In the step S2, the specific parameters of the acid leaching treatment are that the concentration of the hydrochloric acid solution is 1 - 10 M and the impregnation time is 4 - 12 h. The reducing agent is one or more of sodium sulfite, hydroxylamine hydrochloride, and ascorbic acid.
5. The preparation method of the iron-loaded sodalite catalyst using activated sludge incineration ash as a raw material according to claim 3, characterized in that, In the step S3, the impregnation time is 6 - 24 h.
6. An iron - loaded sodalite catalyst using the incinerated ash of activated sludge as raw material, prepared by the method for preparing an iron - loaded sodalite catalyst using the incinerated ash of activated sludge as raw material according to any one of claims 1 to 5.
7. Application of the iron - loaded sodalite catalyst using the incinerated ash of activated sludge as raw material according to claim 6 in the field of Fenton - like catalysis.