Adsorbent for adsorbing V0Cs and preparation method thereof

Abstract

The invention discloses an adsorbent for adsorbing V0Cs and a preparation method of the adsorbent. The adsorbent is prepared from the following raw materials in parts by weight: 50-80 parts of activated carbon, 20-40 parts of titanium dioxide, 10-30 parts of graphene, 10-20 parts of zeolite and 5-15 parts of a metal organic framework material. The preparation method comprises the following steps: S1, mixing the raw materials, adding deionized water, and stirring to form a uniform dispersion liquid; s2, performing ultrasonic treatment on the dispersion liquid, and drying to obtain a precursor; s3, calcining the precursor in a nitrogen atmosphere, and cooling to obtain the adsorbent. The preparation method has the beneficial effects that titanium dioxide realizes adsorption-degradation coupling through photocatalysis, so that the regeneration efficiency is improved; regular pore channels of zeolite realize molecular sieving, and selectivity is improved; the adsorption capacity is further optimized through the ultrahigh specific surface area and the adjustable aperture of the MOFs, dispersion of the nano-particles is promoted through ultrasonic treatment, and agglomeration is avoided; a stable composite interface is formed through high-temperature calcination, and the acting force between materials is enhanced; impurities are removed through acid activation, and the effective pore diameter is enlarged.

Description

Technical Field

[0001] The present invention relates to the technical field of VOCs adsorbents, and specifically to an adsorbent for VOCs adsorption and a preparation method thereof. Background Art

[0002] Volatile organic compounds (VOCs), as one of the main pollutants of air pollution, their treatment technologies have always been a research hotspot. The adsorption method has become one of the mainstream technologies for industrial VOCs treatment due to its simple operation and controllable cost. However, traditional adsorbents such as activated carbon and zeolite have the following technical bottlenecks:

[0003] 1. The adsorption capacity of a single material is limited, and it is difficult to meet the deep treatment requirements of low-concentration and large-volume waste gas;

[0004] 2. The selectivity for polar / non-polar VOCs is insufficient, and it is easily affected by humidity and coexisting gases;

[0005] 3. The energy consumption during the regeneration process is high, and the adsorption cycle life of the adsorbent is short.

[0006] In the prior art, there are many studies on improving the adsorption performance through material compounding, but no mature solution with both high adsorption capacity, strong selectivity and long regeneration cycle has been formed. Therefore, developing a composite adsorbent with multi-component synergistic effect has important practical application value. Summary of the Invention

[0007] The purpose of the present invention is to provide an adsorbent for VOCs adsorption and a preparation method thereof, which can significantly improve the VOCs adsorption performance and regeneration ability through multi-component synergistic modification, so as to solve the problems of the deficiencies of traditional adsorbents in adsorption capacity, selectivity and regeneration performance mentioned in the above background art.

[0008] To achieve the above purpose, the present invention provides the following technical solution: An adsorbent for VOCs adsorption, comprising the following raw materials in parts by weight: 50 - 80 parts of activated carbon, 20 - 40 parts of titanium dioxide, 10 - 30 parts of graphene, 10 - 20 parts of zeolite, and 5 - 15 parts of metal-organic framework material.

[0009] Preferably, the metal-organic framework material is one or a mixture of more than one of ZIF-8, MOF-74, and HKUST-1.

[0010] Preferably, the zeolite is β-zeolite, Y-zeolite, or ZSM-5 zeolite.

[0011] A preparation method of an adsorbent for VOCs adsorption, comprising the following steps:

[0012] S1. Mix the raw materials and then add deionized water, and stir to form a uniformly dispersed liquid;

[0013] S2. Ultrasonically treat the dispersion liquid and then dry it to obtain a precursor;

[0014] S3. Calcinate the precursor in a nitrogen atmosphere and cool it to obtain the adsorbent.

[0015] Preferably, in S1, the solid-liquid ratio of deionized water to the raw material is 1:(5 - 10), the stirring rate is 300 - 500 rpm, and the stirring time is 30 - 60 minutes.

[0016] Preferably, in S2, the ultrasonic treatment temperature is 60 - 80 °C, the ultrasonic frequency is 40 - 60 kHz, the drying temperature is 80 - 100 °C, and the drying time is 12 - 24 hours.

[0017] Preferably, in S3, the calcination heating rate is 5 - 10 °C / minute, the calcination temperature is 500 - 600 °C, the heat preservation time is 2 - 3 hours, and the nitrogen flow rate is 50 - 100 mL / min.

[0018] Preferably, after calcination in S3, it further includes acid activation treatment, and the specific steps are as follows:

[0019] S31. Immerse the calcined product in a 0.1 - 0.5 mol / L hydrochloric acid solution and stir at 50 - 70 °C for 2 - 4 hours;

[0020] S32. After acid activation, filter out the product, wash it with deionized water until neutral, and then dry it at 80 °C for 6 hours.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] Multi-component synergistic enhancement of adsorption performance:

[0023] Activated carbon provides a basic pore structure and adsorption sites; titanium dioxide realizes the coupling of adsorption - degradation through photocatalysis to improve the regeneration efficiency; graphene constructs an electron transport network to promote interfacial charge transfer; the regular pores of zeolite achieve molecular sieving to improve selectivity; the ultra-high specific surface area and adjustable pore size of MOFs further optimize the adsorption capacity.

[0024] Optimization of the preparation process:

[0025] Ultrasonic treatment promotes the dispersion of nanoparticles and avoids agglomeration; high-temperature calcination forms a stable composite interface to enhance the interaction between materials; acid activation removes impurities and enlarges the effective pore size.

[0026] Performance advantages:

[0027] Compared with traditional activated carbon, the adsorption capacity is increased by 30%-50%, the selectivity for typical VOCs such as p-xylene is increased by 20%, and the number of regeneration times can reach more than 7 times. Detailed implementation mode

[0028] The present invention provides a technical solution: an adsorbent for VOCs adsorption, comprising the following raw materials in parts by weight: 50-80 parts of activated carbon, 20-40 parts of titanium dioxide, 10-30 parts of graphene, 10-20 parts of zeolite, and 5-15 parts of metal-organic framework material.

[0029] A preparation method of an adsorbent for VOCs adsorption, comprising the following steps:

[0030] S1. Mix activated carbon, titanium dioxide, graphene, zeolite, and metal-organic framework material in proportion, add deionized water to a solid-liquid ratio of 1:(5-10), and stir at 300-500 rpm for 30-60 minutes to form a uniformly dispersed liquid;

[0031] S2. Ultrasonically treat the dispersed liquid at 60-80°C for 30-60 minutes, with an ultrasonic frequency of 40-60 kHz, and then vacuum dry at 80-100°C for 12-24 hours to obtain a precursor;

[0032] S3. Place the precursor in a tube furnace, heat it to 500-600°C at a heating rate of 5-10°C / minute under a nitrogen atmosphere (flow rate 50-100 mL / min), calcine for 2-3 hours, and naturally cool to room temperature to obtain the adsorbent.

[0033] Among them, after calcination in S3, an acid activation treatment is further included:

[0034] S31. Immerse the calcined product in a 0.1-0.5 mol / L hydrochloric acid solution and stir at 50-70°C for 2-4 hours;

[0035] S32. After acid activation, filter out the product, wash it with deionized water until neutral, and then dry it at 80°C for 6 hours.

[0036] Example 1:

[0037] Basic formula ratio:

[0038] Raw materials: 50 parts of activated carbon, 20 parts of titanium dioxide, 10 parts of graphene, 10 parts of β-zeolite, and 5 parts of ZIF-8.

[0039] Preparation:

[0040] Mix activated carbon, titanium dioxide, graphene, β zeolite, and metal-organic framework materials in proportion, add deionized water until the solid-liquid ratio is 1:5, and stir at 300 rpm for 40 minutes to form a homogeneous dispersion;

[0041] S2. Ultrasonically treat the dispersion at 60 °C for 30 minutes with an ultrasonic frequency of 40 kHz, and then vacuum dry it at 80 °C for 18 hours to obtain a precursor;

[0042] S3. Place the precursor in a tube furnace, heat it to 500 °C at a heating rate of 6 °C per minute under a nitrogen atmosphere (flow rate 60 mL / min), calcine for 2 hours, and naturally cool to room temperature to obtain the adsorbent.

[0043] Example 2

[0044] Optimize the MOFs ratio:

[0045] Raw materials: 60 parts of activated carbon, 30 parts of titanium dioxide, 20 parts of graphene, 15 parts of ZSM-5 zeolite, 10 parts of MOF-74.

[0046] Preparation: Mix activated carbon, titanium dioxide, graphene, β zeolite, and metal-organic framework materials in proportion, add deionized water until the solid-liquid ratio is 1:7, and stir at 400 rpm for 50 minutes to form a homogeneous dispersion;

[0047] S2. Ultrasonically treat the dispersion at 70 °C for 40 minutes with an ultrasonic frequency of 50 kHz, and then vacuum dry it at 90 °C for 18 hours to obtain a precursor;

[0048] S3. Place the precursor in a tube furnace, heat it to 500 °C at a heating rate of 7 °C per minute under a nitrogen atmosphere (flow rate 60 mL / min), calcine for 2 hours, and naturally cool to room temperature to obtain the adsorbent.

[0049] Example 3

[0050] Composite MOFs + acid activation ratio:

[0051] Raw materials: 80 parts of activated carbon, 40 parts of titanium dioxide, 30 parts of graphene, 20 parts of Y zeolite, 15 parts of ZIF-8:MOF-74 (2:1).

[0052] Preparation: Mix activated carbon, titanium dioxide, graphene, zeolite, and metal-organic framework materials in proportion, add deionized water until the solid-liquid ratio is 1:8, add 1% polyethylene glycol, and stir at 500 rpm for 60 minutes to form a homogeneous dispersion;

[0053] S2. Ultrasonically treat the dispersion for 60 minutes at 80 °C with an ultrasonic frequency of 60 kHz, and then vacuum dry it at 100 °C for 24 hours to obtain a precursor;

[0054] S3. Place the precursor in a tubular furnace, heat it to 600 °C at a heating rate of 10 °C / min under a nitrogen atmosphere (flow rate 100 mL / min), calcine for 3 hours, naturally cool to room temperature, immerse the calcined product in a 0.3 mol / L hydrochloric acid solution, stir at 50 - 70 °C for 2 - 4 hours, filter out the product after acid activation, wash it with deionized water until neutral, and then dry it at 80 °C for 6 hours to obtain the adsorbent.

[0055] Performance testing

[0056] Comparison setting

[0057]

[0058] Comparison of experimental parameters:

[0059] Testing conditions:

[0060] VOCs gas: A mixed gas of toluene (1000 ppm) and ethyl acetate (800 ppm);

[0061] Adsorption temperature: 25 °C, adsorption time: 60 min, gas flow rate: 50 mL / min

[0062] Regeneration conditions: Purge with hot nitrogen at 120 °C (flow rate 100 mL / min), regeneration time 30 min;

[0063] Test results

[0064]

[0065] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An adsorbent for VOCs adsorption, characterized in that: The invention comprises the following raw materials in parts by weight: 50-80 parts of activated carbon, 20-40 parts of titanium dioxide, 10-30 parts of graphene, 10-20 parts of zeolite and 5-15 parts of metal organic framework material.

2. The adsorbent for VOCs adsorption according to claim 1, characterized in that: The metal organic framework material is a mixture of one or more of ZIF-8, MOF-74 and HKUST-1.

3. The adsorbent for VOCs adsorption according to claim 1, characterized in that: The zeolite is β zeolite, Y zeolite or ZSM-5 zeolite.

4. A method for preparing an adsorbent for VOCs adsorption, characterized in that: The following steps are involved: S1. After mixing the raw materials, add deionized water and stir to form a uniform dispersion; S2, subjecting the dispersion to ultrasonic treatment and drying to obtain a precursor; S3, calcining the precursor under a nitrogen atmosphere, and obtaining the adsorbent after cooling.

5. The method for preparing an adsorbent for VOCs adsorption according to claim 4, characterized in that: The solid-liquid ratio of deionized water to raw materials in S1 is 1:(5-10), the stirring rate is 300-500 rpm, and the stirring time is 30-60 minutes.

6. The method for preparing an adsorbent for VOCs adsorption according to claim 4, characterized in that: In the S2, the ultrasonic treatment temperature is 60-80°C, the ultrasonic frequency is 40-60kHz, the drying temperature is 80-100°C, and the drying time is 12-24 hours.

7. The method for preparing an adsorbent for VOCs adsorption according to claim 4, characterized in that: In the S3, the calcination heating rate is 5-10°C / min, the calcination temperature is 500-600°C, the insulation time is 2-3 hours, and the nitrogen flow rate is 50-100 mL / min.

8. The method for preparing an adsorbent for VOCs adsorption according to claim 4, characterized in that: The S3 further includes an acid activation treatment after calcination, and the specific steps are as follows: S31, immersing the calcined product in a 0.1-0.5 mol / L hydrochloric acid solution, and stirring at 50-70° C. for 2-4 hours; S32. After the acid activation is completed, the product is filtered out, washed with deionized water until neutral, and then dried at 80° C. for 6 hours.

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