Carbon zeolite hierarchical pore materials with efficient adsorption, preparation methods and applications

Abstract

The present invention relates to the field of wastewater treatment functional materials, and provides a carbon zeolite hierarchical pore material with high adsorption efficiency, a preparation method and an application. The method includes: S1 Acid leaching treatment: grinding and screening coal-based carbon-containing solid waste, mixing it with an appropriate amount of acid solution and heating it in a water bath to carry out an acid dissolution reaction; separating solid and liquid, washing and drying to obtain an acid leaching product; S2 Alkali melting activation treatment: mixing the acid leaching product with alkali evenly, heating it to melting in an airtight manner, keeping it warm for a certain time, and cooling to obtain an activated product; S3 Hydrothermal crystallization treatment: adding an appropriate amount of deionized water to the activated product, and then carrying out hydrothermal crystallization in a reaction kettle; washing the product after hydrothermal crystallization to neutrality and drying it to obtain the carbon zeolite hierarchical pore material. The material of the present invention has good physical and chemical adsorption and ion exchange properties, the preparation process is simple, and the cost is low. It realizes the comprehensive utilization of all components of coal-based carbon-containing solid waste and can efficiently adsorb ammonia nitrogen in water pollutants.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment functional materials, and particularly relates to a carbon zeolite hierarchical pore material with high adsorption efficiency, a preparation method and an application thereof. Background Art

[0002] Coal is the main energy source in China, and coal-based solid wastes also cause certain environmental pollution. It is urgent to develop new and efficient utilization ways. Among them, carbon-containing coal-based solid wastes such as coal gasification slag and coal gangue contain some residual carbon, forming a porous structure, which are potential raw materials for preparing porous materials. At the same time, ammonia nitrogen in the wastewater generated by coal chemical industry, as a typical pollutant, needs to be treated urgently. In the treatment of ammonia nitrogen, the adsorption method is the most commonly used method for adsorbing ammonia nitrogen, and common adsorbents include porous carbon, zeolite, resin, etc. Synthesizing low-cost and high-performance adsorbents is the key to developing adsorption methods.

[0003] However, as synthetic materials for adsorbents, there are generally problems such as complex preparation processes and high preparation costs.

[0004] Science and technology are advancing by leaps and bounds, and various new materials are emerging in an endless stream. Hierarchical pore materials have excellent performance in adsorption compared with single pore channels. Carbon-containing coal-based solid wastes contain components such as carbon, Si, and Al, which are potential raw materials for synthesizing carbon zeolite porous materials, and can combine the respective characteristics of porous carbon and zeolite molecular sieves. Zeolite has an open crystal structure, with regular and uniform pore structures, a large cation exchange capacity and good metal ion adsorption performance, and its surface shows hydrophilicity. Porous carbon has a developed pore structure, is easy to prepare, has a low price, its surface shows hydrophobicity, and has a good adsorption effect on organic molecules. Summary of the Invention

[0005] The purpose of the present invention is to at least overcome one of the deficiencies of the prior art, and provide a carbon zeolite hierarchical pore material with high adsorption efficiency, a preparation method and an application thereof. Compared with traditional chemically synthesized carbon zeolite composites, the preparation process is simple, the cost is relatively low, and the adsorption effect is better.

[0006] The present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a preparation method of a carbon zeolite hierarchical pore material with high adsorption efficiency, including:

[0008] S1. Acid leaching treatment: Grinding and screening coal-based carbon-containing solid waste, mixing it with an acid solution and heating it in a water bath to carry out an acid dissolution reaction; separating the solid and liquid of the material after the acid dissolution reaction, washing and drying to obtain an acid leaching product;

[0009] S2. Alkali melting activation treatment: Mixing the acid leaching product obtained in step S1 with alkali evenly, heating it to melting in an airtight manner, keeping it warm for a certain time, and then cooling to obtain an activated product;

[0010] S3. Hydrothermal crystallization treatment: The activated product after the activation treatment in step S2 is added with deionized water, and then heated for a set time for hydrothermal crystallization; the product after hydrothermal crystallization is washed to neutral and dried to obtain the carbon zeolite hierarchical pore material.

[0011] In any of the possible implementation manners as described above, a further implementation manner is provided. In step S1, the coal-based carbon-containing solid waste is ground and screened to less than 200 meshes, and after solid-liquid separation, the acid-leaching product is dried, and the drying temperature is 90 - 105 °C.

[0012] In any of the possible implementation manners as described above, a further implementation manner is provided. In step S1, the acid solution is hydrochloric acid or nitric acid, the acid concentration is 5 - 20 wt%, and the acid dissolution reaction time is 5 - 9 h.

[0013] In any of the possible implementation manners as described above, a further implementation manner is provided. In step S2, after the acid-leaching product is mixed with alkali evenly, it is kept warm at 650 - 850 °C for 2 - 3 h in an inert atmosphere of a tubular furnace and then cooled to room temperature.

[0014] In any of the possible implementation manners as described above, a further implementation manner is provided. In step S3, the hydrothermal crystallization temperature in the reaction kettle is 80 - 200 °C, and the reaction time is > 10 h.

[0015] In any of the possible implementation manners as described above, a further implementation manner is provided. In step S3, the product after hydrothermal crystallization is washed with distilled water to neutral and dried at 80 °C.

[0016] On the other hand, the present invention also provides a carbon zeolite hierarchical pore material with high adsorption efficiency, and the carbon zeolite hierarchical pore material is prepared by the above method.

[0017] In any of the possible implementation manners as described above, a further implementation manner is provided. Carbon provides hierarchical pores, and zeolite is located on the surface and in the pores of the porous carbon to form a hierarchical pore structure; the total specific surface area of the carbon zeolite hierarchical pore material reaches 198.26 m2 / g.

[0018] On the other hand, the present invention also provides an application of the above carbon zeolite hierarchical pore material with high adsorption efficiency. The carbon zeolite hierarchical pore material is applied to the adsorption wastewater process, the equilibrium adsorption capacity for ammonia nitrogen reaches 49.26 mg / g; the adsorption rate for ammonia nitrogen reaches 98.56%.

[0019] The beneficial effects of the present invention are:

[0020] 1. The total specific surface area of the porous composite material of the present invention is 198.26 m2 / g. At the beginning of adsorption, the ammonia nitrogen concentration in the solution is high, the concentration difference between the solution and the material surface is large, the driving force is large, and at the beginning of adsorption, there are many adsorption sites and the adsorption rate is fast. Especially in the first 90 minutes, the adsorption amount increases significantly. As the adsorption time increases, the adsorption sites gradually decrease, the adsorption amount increases slowly, and basically remains unchanged after 3 hours. This is because after the ammonia nitrogen adsorption reaches saturation, an ion exchange equilibrium occurs between the material and the solution, thus reaching the adsorption equilibrium. The equilibrium adsorption amount of ammonia nitrogen is 49.26 mg / g; the adsorption rate of ammonia nitrogen reaches 98.56%.

[0021] 2. The present invention uses coal gasification slag as the main raw material, with low raw material cost, prepares a carbon zeolite porous composite material with high adsorption activity, realizes the comprehensive utilization of elements C, Si, Al, and Ca in coal gasification slag, is environmentally friendly, and has high added value.

[0022] 3. The preparation method of the carbon zeolite porous composite material of the present invention opens up a new way for the comprehensive utilization of coal gasification slag, and at the same time provides a new type of high-efficiency adsorbent for wastewater adsorption treatment. Brief Description of the Drawings

[0023] Figure 1 The following shows the preparation flow chart of the preparation method of a carbon zeolite multi-stage pore material with high adsorption efficiency according to an embodiment of the present invention.

[0024] Figure 2 The following shows the XRD pattern of the carbon zeolite multi-stage pore material prepared in the embodiment.

[0025] Figure 3 The following shows the SEM image of the carbon zeolite multi-stage pore material prepared in the embodiment.

[0026] Figure 4 The following shows the legend of the ammonia nitrogen adsorption performance analysis of the carbon zeolite multi-stage pore material prepared in the embodiment. Detailed Embodiments

[0027] The following will describe the specific embodiments of the present invention in detail with reference to the specific drawings. It should be noted that the technical features described in the following embodiments or the combinations of technical features should not be considered as isolated, and they can be combined with each other to achieve better technical effects.

[0028] As Figure 1 shown, the preparation method of a carbon zeolite multi-stage pore material with high adsorption efficiency according to an embodiment of the present invention includes:

[0029] S1. Acid leaching treatment: Grind and screen the coal-based carbon-containing solid waste, mix it with an appropriate amount of acid solution and heat it in a water bath to carry out an acid dissolution reaction; perform solid-liquid separation on the material after the acid dissolution reaction, wash and dry it to obtain an acid leaching product;

[0030] S2. Alkali fusion activation treatment: Mix the acid-leached product obtained in step S1 with alkali evenly, then heat it to melting in an airtight environment, keep it warm for a certain period of time, and cool it to obtain an activated product.

[0031] S3. Hydrothermal crystallization treatment: Add appropriate amount of deionized water to the activated product after the activation treatment in step S2, and then heat it for a set time for hydrothermal crystallization; Wash the product after hydrothermal crystallization to neutrality and dry it to obtain the carbon zeolite hierarchical porous material.

[0032] In a specific embodiment, in step S1, the coal-based carbon-containing solid waste is ground and screened to less than 200 mesh, and after solid-liquid separation, the acid-leached product is dried at a drying temperature of 90 - 105 °C.

[0033] In a specific embodiment, in step S1, the acid solution is hydrochloric acid or nitric acid, the acid concentration is 5 - 20 wt%, and the acid dissolution reaction time is 5 - 9 h.

[0034] In a specific embodiment, in step S2, after the acid-leached product is mixed with alkali evenly, it is kept warm at 650 - 850 °C for 2 - 3 h in an inert atmosphere in a tubular furnace and then cooled to room temperature.

[0035] Alkali fusion activation is the action of NaOH on the silicon-aluminum and carbon components in the raw material. The addition of strong alkali can, on the one hand, break the Si—O—Si and Si—O—Al bonds therein, and convert the silicon-aluminum components (such as kaolinite, mullite, quartz, etc.) existing in crystalline form in the raw material into amorphous aluminosilicates with higher reaction activity, promoting the subsequent hydrothermal reaction. On the other hand, it expands the original pores and transforms them into activated carbon. In the present invention, the silicon-aluminum-carbon components are treated simultaneously during alkali fusion activation, promoting the subsequent hydrothermal crystallization to generate hierarchical pores and improving the adsorption performance.

[0036] In a specific embodiment, in step S3, the hydrothermal crystallization temperature in the reaction kettle is 80 - 200 °C, and the reaction time is > 10 h.

[0037] In a specific embodiment, in step S3, the product after hydrothermal crystallization is washed with distilled water to neutrality and dried at 80 °C.

[0038] On the other hand, in an embodiment of the present invention, there is provided a carbon zeolite hierarchical porous material with high adsorption efficiency, and the carbon zeolite hierarchical porous material is prepared by the above method.

[0039] In a specific embodiment, carbon provides hierarchical pores, and zeolite is located on the surface and in the pores of the porous carbon to form a hierarchical pore structure; the total specific surface area of the carbon zeolite hierarchical porous material reaches 198.26 m2 / g.

[0040] On the other hand, an embodiment of the present invention provides an application of the above-mentioned carbon zeolite hierarchical pore material with high adsorption efficiency. The carbon zeolite hierarchical pore material is applied to the process of adsorbing wastewater, and the equilibrium adsorption capacity for ammonia nitrogen reaches 49.26 mg / g; the adsorption rate for ammonia nitrogen reaches 98.56%.

[0041] Example

[0042] This example provides a preparation method of a hierarchical pore material. The hierarchical pore material uses raw material coal gasification slag with a carbon content of 45.34%. The composition of the ash is as follows:

[0043] Chemical composition of coal gasification slag (%)

[0044]

[0045] The preparation method includes: acid leaching treatment of gasification slag, alkali melting and hydrothermal crystallization. The zeolite synthesis solution includes strong alkaline hydroxide or mixed alkali, aluminum source, water, etc. An appropriate amount of aluminum source (such as alumina) is added before alkali melting activation to adjust the silicon-aluminum molar ratio. After alkali melting activation, no seed crystal is needed, and no aging is required. Deionized water is directly added for hydrothermal reaction.

[0046] Dry the gasification fine slag at 100 °C for 12 h, grind it through a standard sieve with a pore diameter of 200 mesh, and take 10 g for standby.

[0047] First, put 5 g of slag into 15 wt% hydrochloric acid for pickling to remove impurity metal oxides in the gasification fine slag, wash it with deionized water until the filtrate is neutral, and place the sample in a drying oven at 105 °C to dry to obtain the acid-leached slag.

[0048] Secondly, mix the acid-leached slag and NaOH evenly at a ratio of 3:1, place them in a tube furnace, and under an Ar atmosphere, carry out alkali melting of the sample at 800 °C for 2 h. Then take out the product after alkali melting, and then mix the alkali melt with deionized water at a solid-liquid ratio of 1:5 evenly, and then transfer it to a reaction kettle. Place the reaction kettle in an oven at 100 °C for 10 h. Wash the obtained solid material with deionized water until it is neutral, and then dry it at 80 °C for 24 hours to obtain the carbon zeolite hierarchical pore material.

[0049] The crystallization conditions for hydrothermal crystallization are a temperature of 80 - 200 °C and a time of ≥10 h.

[0050] The crystallization temperature for hydrothermal crystallization can be 80 - 200 °C.

[0051] The crystallization time for hydrothermal crystallization is 10 h - 24 h.

[0052] The carbon zeolite hierarchical pore material prepared by the present invention is compared with other adsorption materials as follows:

[0053] Comparison of the Adsorption Effects of Different Adsorbents on Ammonia Nitrogen

[0054]

[0055]

[0056] The XRD pattern of the prepared carbon-zeolite hierarchical pore material is as Figure 2 shown. The diffraction peaks of the crystallized sample belong to the characteristic diffraction peaks of zeolite A, indicating that the carbon-zeolite A hierarchical pore material has been successfully prepared by hydrothermal crystallization; during the hydrothermal crystallization process, silicon and aluminum elements in the gasification slag form zeolite A.

[0057] The SEM image of the prepared carbon-zeolite hierarchical pore material is as Figure 3 shown. The diameter of the zeolite A crystals is approximately 1 μm, and the large number of pore structures present in the carbon skeleton provide suitable sites for the growth of zeolite crystals. This enables the zeolite crystals to be embedded in the pores of the carbon skeleton, jointly forming a hierarchical pore structure with interconnected micropores, mesopores, and macropores, thus significantly improving the adsorption efficiency.

[0058] The ammonia nitrogen adsorption performance of the prepared carbon-zeolite hierarchical pore material is as Figure 4 shown. The adsorption process of ammonia nitrogen by the carbon-zeolite hierarchical pore material can be divided into three stages: rapid adsorption, adsorption slowdown, and adsorption equilibrium. When adsorption reaches equilibrium, the adsorption capacity reaches 49.26 mg / g.

[0059] The material of the present invention has good physical, chemical adsorption, and ion exchange properties, a simple preparation process, and low cost. It realizes the comprehensive utilization of all components of coal-based carbon-containing solid waste and can efficiently adsorb ammonia nitrogen, a water pollutant.

[0060] Although several embodiments of the present invention have been given in this article, those skilled in the art should understand that the embodiments in this article can be changed without departing from the spirit of the present invention. The above embodiments are only exemplary and should not be used as a limitation of the scope of the rights of the present invention.

Claims

1. A method for preparing a high-efficiency adsorption carbon zeolite hierarchical porous material, characterized in that: The method comprises: S1. Acid leaching treatment: Grind and screen the coal-based carbonaceous solid waste, mix it with an acid solution and heat it in a water bath to carry out an acid dissolution reaction; separate the solid and liquid of the material after the acid dissolution reaction, wash it, and dry it to obtain an acid leaching product; S2, alkali melting activation treatment: adding alkali to the acid leaching product obtained in step S1, mixing evenly, isolating from air, heating until melting, keeping the temperature for a certain period of time, and cooling to obtain an activated product; S3, hydrothermal crystallization treatment: adding deionized water to the activated product after the activation treatment in step S2, stirring appropriately, and then heating for a set time for hydrothermal crystallization; washing the hydrothermal crystallized product to neutrality, and drying to obtain the carbon zeolite multi-level porous material with high efficiency adsorption; the equilibrium adsorption amount of ammonia nitrogen by the carbon zeolite multi-level porous material with high efficiency adsorption reaches 49.26 mg / g; and the adsorption rate of ammonia nitrogen reaches 98.56%; In step S1, the coal-based carbonaceous solid waste is ground and sieved to less than 200 meshes, and the acid leaching product is dried after solid-liquid separation, and the drying temperature is 90-105°C; In step S1, the acid solution is hydrochloric acid or nitric acid, the acid concentration is 5-20wt%, and the acid dissolution reaction time is 5-9h; In step S2, the acid leaching product is mixed with alkali and then kept at 650-850° C. for 2-3 hours in an inert atmosphere of a tube furnace, and then cooled to room temperature; In step S3, hydrothermal crystallization is carried out in a reactor, the hydrothermal crystallization temperature is 80-200° C., and the reaction time is greater than 10 h.

2. The method for preparing the high-efficiency adsorption carbon zeolite hierarchical porous material according to claim 1, characterized in that: In step S3, the product after hydrothermal crystallization is washed with distilled water until neutral and dried at 80°C.

3. A high-efficiency adsorption carbon zeolite hierarchical porous material, characterized in that: The carbon zeolite hierarchical porous material is prepared by the method according to any one of claims 1-2.

4. The high-efficiency adsorption carbon zeolite hierarchical porous material according to claim 3, characterized in that: The carbon provides multi-level pores, and the zeolite is located on the surface and in the pores of the porous carbon to form a multi-level pore structure; the total specific surface area of ​​the carbon zeolite multi-level pore material reaches 198.26m 2 / g.

5. The use of the carbon zeolite hierarchical porous material with high efficiency of adsorption as claimed in claim 3 or 4, characterized in that: The carbon zeolite multi-level porous material is used in the wastewater adsorption process.

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