Adsorbent as well as preparation method and application thereof

Abstract

The invention discloses an adsorbent and a preparation method and application thereof, and the method comprises the following steps: (1) mixing a surfactant, n-butyl alcohol, deionized water, concentrated hydrochloric acid and tetraethoxysilane to obtain a first reaction solution; (2) carrying out hydrothermal reaction on the first reaction solution to obtain a second reaction solution; (3) after the second reaction liquid is cooled, carrying out solid-liquid separation, washing and drying to obtain a silicon dioxide precursor; and (4) mixing rare earth nitrate hydrate powder with the silicon dioxide precursor, grinding, and calcining to obtain the adsorbent. Therefore, the adsorbent has the advantages of being large in adsorption capacity, high in selectivity, simple in preparation method, easy to implement and the like.

Description

Technical Field

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

[0002] Environmental pollution caused by the conversion of sulfides in fuel into SOx is a major environmental problem. SOx emissions into the atmosphere will form acid rain, destroy forest ecosystems, and lead to the loss of biodiversity. Excessive SOx emissions will also lead to global warming, further exacerbating the problem of global climate change. Therefore, countries strictly control the sulfur content of fuel, and low sulfide or even zero sulfide will become a general trend. The main components of fuel are alkanes, olefins, aromatic hydrocarbons and sulfur-containing compounds, among which sulfur-containing compounds are aromatic sulfides such as thiophene (TP), benzothiophene (BT), dibenzothiophene (DBT) and non-aromatic sulfides such as hydrogen sulfide, mercaptan, and sulfide. Traditional hydrodesulfurization (HDS) can efficiently remove non-aromatic sulfides in fuel, but the elimination of aromatic sulfides requires a significant increase in hydrogen and energy input, but this cannot ensure the maintenance of the octane number of the fuel. The removal of aromatic sulfides requires more hydrogen and higher energy, and the octane number of the fuel cannot be guaranteed. Therefore, the existing technology needs to be improved. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. The present invention provides an adsorbent, which is a new adsorbent material suitable for the field of adsorption desulfurization, and has the advantages of large adsorption capacity, high selectivity, simple preparation method, and easy implementation.

[0004] In one aspect of the present invention, the present invention provides a method for preparing an adsorbent. According to an embodiment of the present invention, the method comprises:

[0005] (1) mixing a surfactant, n-butanol, deionized water, concentrated hydrochloric acid and tetraethyl orthosilicate to obtain a first reaction solution;

[0006] (2) subjecting the first reaction solution to a hydrothermal reaction to obtain a second reaction solution;

[0007] (3) after the second reaction liquid is cooled, solid-liquid separation, washing and drying are performed to obtain an ultra-microporous silica precursor;

[0008] (4) Mixing rare earth nitrate hydrate powder with the ultra-microporous silica precursor, grinding and calcining to obtain the adsorbent.

[0009] In some embodiments, in step (1), the surfactant includes at least one of PEO24-PPO36-PEO24, PEO5-PPO20-PEO5 and PEO7-PPO32-PEO7.

[0010] In some embodiments, in step (1), the molar ratio of the mixture of n-butanol, surfactant, deionized water, concentrated hydrochloric acid and tetraethyl orthosilicate is (0.70-1.20):(0.018-0.022):(140-155):(1.45-1.50):(0.70-0.90).

[0011] In some embodiments, in step (1), the concentration of the concentrated hydrochloric acid is 35-45 wt %.

[0012] In some embodiments, in step (1), the mixing comprises: stirring at 30-50° C. and 200-400 rpm for 18-36 hours.

[0013] In some embodiments, in step (2), the hydrothermal reaction conditions are: reacting at 80-120° C. for 12-36 hours.

[0014] In some embodiments, in step (4), the mass ratio of the rare earth nitrate hydrate powder to the ultra-microporous silica precursor is (0.02-0.16):1, preferably (0.06-0.10):1.

[0015] In some embodiments, in step (4), the rare earth nitrate hydrate includes at least one of lanthanum nitrate hexahydrate and cerium nitrate hexahydrate.

[0016] In some embodiments, in step (4), the calcination conditions are: calcination at 673-923K for 1-5h, preferably calcination at 773-873K for 2-4h.

[0017] In some embodiments, in step (4), the grinding time is 10 to 40 minutes.

[0018] In the second aspect of the present invention, the present invention provides an adsorbent. According to an embodiment of the present invention, the adsorbent is prepared by the method described in the first aspect of the present invention, and the pore size of the adsorbent is 1.12-1.71 nm, and the pore volume is 0.40-0.49 cm 3 / g, specific surface area is 689~871m 2 / g.

[0019] In a third aspect of the present invention, the present invention provides an application of the adsorbent described in the second aspect of the present invention. According to an embodiment of the present invention, the application includes: the adsorbent adsorbs sulfides in oil products.

[0020] In some embodiments, the adsorption includes the following steps: contacting the oil product with the above-mentioned adsorbent, wherein the sulfide in the oil product includes one or more of oil thiophene, benzothiophene, and dibenzothiophene, the sulfide concentration in the oil product is 100-500 ppmw, the simulated oil flow rate is 0.01-0.05 mL / min, the adsorption temperature is 30-50°C, and the adsorption pressure is 1 bar.

[0021] In summary, this aspect has the following beneficial effects:

[0022] 1. The adsorbent of the present invention has a very small pore size and a large specific surface area. In addition, due to the presence of a microenvironment between the template and the pore wall in the silica precursor, the rare earth elements can be directly confined in the microenvironment, thereby enhancing the dispersion amount and degree of the rare earth elements, thereby improving the adsorption performance of the silica material.

[0023] 2. The adsorbent prepared by the present invention has high adsorption efficiency and large adsorption capacity, can be used to adsorb sulfides in oil products, and has good application prospects.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0026] Example 1

[0027] (1) 7.8 g of a triblock copolymer surfactant (PEO24-PPO36-PEO24, molecular weight Mw=4150) and 8.0 g of n-butanol and 260 g of deionized water were mixed at 35° C. and magnetically stirred at 250 rpm for 12 hours. Then, 12.5 mL of 37 wt% concentrated hydrochloric acid and 16.5 g of tetraethyl orthosilicate were added simultaneously. After stirring for 24 hours, the mixture was transferred to a reactor and subjected to hydrothermal reaction at 100° C. for 24 hours. After natural cooling, the mixture was filtered, washed with distilled water until neutral, and dried to obtain a silica precursor.

[0028] (2) 0.06 g of lanthanum nitrate hexahydrate powder and 1 g of silica precursor powder were mixed evenly to obtain powder mixture A, and the powder mixture A was ground in a mortar for 30 min to obtain powder mixture B. The powder mixture B was placed in a tubular furnace and calcined at 773 K for 4 h at a heating rate of 5 ° C / min in an air atmosphere, and then pressed into tablets at 20 MPa and ground into 40-60 mesh particles to obtain an adsorbent.

[0029] Example 2

[0030] In step (2), the amount of lanthanum nitrate hexahydrate powder is 0.02 g, and the rest is the same as in Example 1.

[0031] Example 3

[0032] In step (2), the amount of lanthanum nitrate hexahydrate powder is 0.10 g, and the rest is the same as in Example 1.

[0033] Example 4

[0034] In step (2), the amount of lanthanum nitrate hexahydrate powder is 0.16 g, and the rest is the same as in Example 1.

[0035] Example 5

[0036] The calcination conditions in step (2) are: calcination at 873K for 2h.

[0037] Example 6

[0038] The calcination conditions in step (2) are: calcination at 673K ​​for 5 hours.

[0039] Example 7

[0040] The calcination conditions in step (2) are: calcination at 923K for 1 h.

[0041] Comparative Example 1

[0042] In step (1), the amount of lanthanum nitrate hexahydrate powder is 0.01 g, and the rest is the same as in Example 1.

[0043] Comparative Example 2

[0044] The silica precursor in step (1) of Example 1 is further subjected to a template removal treatment: the silica precursor is ground and then heated to 550° C. in a muffle furnace at a rate of 1° C. / min and calcined for 6 hours to obtain an ultra-microporous silica adsorbent.

[0045] Comparative Example 3

[0046] 0.06 g of lanthanum nitrate hexahydrate powder and 1 g of the ultra-microporous silica adsorbent powder in Comparative Example 2 were evenly mixed to obtain powder mixture A, and the powder mixture A was ground in a mortar for 30 min to obtain powder mixture B. The powder mixture B was placed in a tubular furnace and calcined at 773 K for 2 h at a heating rate of 5 ° C / min in an air atmosphere, and then pressed into tablets at 20 MPa and ground into 40-60 mesh particles to obtain an adsorbent.

[0047] Comparative Example 4

[0048] The calcination conditions in step (2) are: calcination at 973K for 1 h.

[0049] The adsorbent prepared in Examples 1-7 and Comparative Examples 1-4 was loaded into a quartz tube, and the performance was tested using a fixed bed reactor, and the sulfur content was determined using a gas chromatograph. The sulfide content in the simulated oil was as follows: 500 ppmw of thiophene, balanced with n-octane. The specific operation is as follows: In a fixed bed reactor, an appropriate amount of quartz wool is filled in the bottom layer, and then the adsorbent and an appropriate amount of quartz sand are filled. The simulated oil passes through a fixed bed device and enters a fixed bed reactor for purification, and samples are taken at the end of the fixed bed reactor. The sulfide content in the purified simulated oil is detected by an Agilent gas chromatograph, and the penetration adsorption sulfur capacity and the saturated adsorption sulfur capacity are obtained. The test results are listed in Table 1. Among them, the thiophene content in the simulated oil is 500 ppm, the flow rate of the simulated oil is 0.04 mL / min, the adsorption temperature is 30°C, and the adsorption pressure is 1 bar.

[0050] Table 1 Test results of adsorbent performance corresponding to the examples and comparative examples

[0051]

[0052] It can be seen from the control data of the embodiments and comparative examples that the technical solution provided by the present invention solves the problems of poor dispersibility, low dispersion amount, low adsorption capacity, etc. of the current silica adsorbent, and achieves good technical effects. By utilizing the structural properties of the ultra-microporous silica material itself, especially the microenvironment between the template and the pore wall in the ultra-microporous silica precursor, the rare earth elements are directly confined in the microenvironment. The method is simple and efficient, and the dispersion amount and degree of the rare earth elements are enhanced, thereby improving the adsorption performance of the original adsorption material.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0054] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an adsorbent, characterized in that: The method comprises: (1) mixing a surfactant, n-butanol, deionized water, concentrated hydrochloric acid and tetraethyl orthosilicate to obtain a first reaction solution; (2) subjecting the first reaction liquid to a hydrothermal reaction to obtain a second reaction liquid; (3) after the second reaction liquid is cooled, solid-liquid separation, washing and drying are performed to obtain a silicon dioxide precursor; (4) After mixing rare earth nitrate hydrate powder with the silicon dioxide precursor, grinding and calcining to obtain the adsorbent.

2. The method according to claim 1, characterized in that In step (1), the surfactant includes at least one of PEO24-PPO36-PEO24, PEO5-PPO20-PEO5 and PEO7-PPO32-PEO7; and / or, The molar ratio of the n-butanol, surfactant, deionized water, concentrated hydrochloric acid and tetraethyl orthosilicate is (0.70-1.20): (0.018-0.022): (140-155): (1.45-1.50): (0.70-0.90).

3. The method according to claim 1, characterized in that The concentration of the concentrated hydrochloric acid is 35-45wt%; and / or, The mixing includes: stirring at 30-50° C. and 200-400 rpm for 18-36 hours.

4. The method according to claim 1, characterized in that: In step (2), the hydrothermal reaction conditions are: reaction at 80-120° C. for 12-36 hours.

5. The method according to claim 1, characterized in that In step (4), the mass ratio of the rare earth nitrate hydrate powder to the silicon dioxide precursor is (0.02-0.16):1, preferably (0.06-0.10):1; and / or, The rare earth nitrate hydrate includes at least one of lanthanum nitrate hexahydrate and cerium nitrate hexahydrate.

6. The method according to claim 1, characterized in that The calcination conditions are: calcination at 673-923K for 1-5h, preferably calcination at 773-873K for 2-4h; and / or, The grinding time is 10 to 40 minutes.

7. An adsorbent, characterized in that The adsorbent is prepared by the method according to any one of claims 1 to 6, and the pore diameter of the adsorbent is 1.12 to 1.71 nm, and the pore volume is 0.40 to 0.49 cm 3 / g, specific surface area is 689~871m 2 / g.

8. Use of the adsorbent according to claim 7, characterized in that: The application includes: the adsorbent adsorbs sulfides in oil products.

9. The use according to claim 8, characterized in that: The adsorption comprises the following steps: contacting the oil product with the adsorbent according to claim 8, wherein the sulfide in the oil product comprises one or more of oil thiophene, benzothiophene, and dibenzothiophene, the sulfide concentration in the oil product is 100-500 ppmw, the simulated oil flow rate is 0.01-0.05 mL / min, the adsorption temperature is 30-50°C, and the adsorption pressure is 1 bar.

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