Marine biomass desulfurization catalyst and preparation method thereof

Abstract

The invention discloses a marine biomass desulfurization catalyst and a preparation method thereof, and belongs to the technical field of catalysis. The catalyst takes marine biomass as a carbon source carrier, a metal aqueous solution is slowly added into the carbon source carrier to prepare a uniformly dispersed carbon metal solution, the uniformly dispersed carbon metal solution and sodium hydroxide are mixed and subjected to a hydrothermal synthesis reaction to obtain a precursor of the catalyst, and the catalyst precursor is subjected to centrifugal washing and drying to obtain the catalyst. And carrying out heat treatment on the obtained filter cake to prepare the marine biomass desulfurization catalyst. The prepared catalyst mainly takes marine biomass as a porous carbon carrier, and compared with traditional porous carbon materials such as polyacrylonitrile and polyethylene glycol, the catalyst is cheap, easy to obtain and environmentally friendly. Meanwhile, the desulfurization catalyst is prepared into nanowire morphology through a hydrothermal synthesis method, the metal aggregation degree is small, the number of metal active centers in unit area is large, the metal dispersity is large, and good adsorption desulfurization performance is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a method for preparing a marine biomass desulfurization catalyst. Background Art

[0002] Automobile exhaust contains a large amount of sulfur oxides. The emission of such sulfur oxides will lead to ozone layer depletion, acid rain formation, reduced soil fertility, and harm to human health. Therefore, desulfurization from petroleum fuels and their intermediate products is crucial to protecting the environment and human life safety. Adsorption desulfurization is a current research hotspot due to its mild reaction conditions, low octane loss, and ability to achieve deep desulfurization. The core of adsorption desulfurization lies in the development of high-performance adsorbents. Currently, adsorbents mainly include metal oxides, zeolites, metal organic frameworks, carbon materials, etc. Among them, carbon materials are widely used as adsorbents due to their low cost, high specific surface area, and adjustable pores.

[0003] At present, carbon materials loaded with transition metals have been used for adsorption desulfurization. In addition to having a large surface area, this material can also desulfurize liquid fuels by forming metal-sulfur complexes. The adsorption of sulfur-containing compounds by carbon materials mainly depends on the distribution of metal active sites on their surfaces and the number of oxygen-containing functional groups. Therefore, the development of green, environmentally friendly, cheap and easily available porous carbon materials is of great significance for the preparation of high-performance desulfurization adsorbents.

[0004] With the rise of the marine economy, seeking advice from the ocean is one of the ways to solve the shortage of fossil resources. The ocean is vast and rich in biological resources, which is an excellent environment for the development of biomass energy. Biomass materials have the advantages of abundant sources and renewability, and have important application prospects in the field of sustainable energy material development. The abundant Enteromorpha, Zostera maria, and Kelp in the ocean are natural porous carbon materials in themselves, and are cheap and easy to obtain, with rich species, and can replace traditional porous carbon materials such as polyacrylonitrile, polyethylene glycol, etc. Using this biomass material as a porous carbon carrier for a desulfurization catalyst, the research and development of high-performance desulfurization catalysts has important ecological, economic and social benefits, and at present, there is no use of marine biomass such as Enteromorpha, Zostera maria, and Kelp for the preparation of desulfurization catalysts. Summary of the invention

[0005] The purpose of the present invention is to provide a marine biomass desulfurization catalyst and a preparation method thereof. The catalyst mainly uses marine biomass as a porous carbon carrier, is cheap, easy to obtain, and green and environmentally friendly. At the same time, the desulfurization catalyst is made into a nanowire morphology by a hydrothermal synthesis method, and has a small degree of metal aggregation, a large number of metal active centers per unit area, a large metal dispersion, and good adsorption desulfurization performance.

[0006] In order to achieve the above technical objectives, the present invention proposes a marine biomass desulfurization catalyst, characterized in that the catalyst comprises a carbon source carrier using marine biomass as raw material and a metal active component, the mass ratio of the metal active component to the carbon source carrier is 1:1-3; the mesopore specific surface area and mesopore volume of the catalyst are 85-100 m 2 / g, 0.150~0.170 cm 3 / g.

[0007] The present invention provides a method for preparing a marine biomass desulfurization catalyst, which uses marine biomass as a carbon source carrier, slowly adds a metal aqueous solution to the carbon source carrier to prepare a uniformly dispersed carbon-metal solution, and then subjecting the uniformly dispersed carbon-metal solution to a hydrothermal synthesis method to prepare the marine biomass desulfurization catalyst.

[0008] Generally, the preparation method of the catalyst of the present invention is as follows: the marine biomass is first pretreated, and the pretreated marine biomass is dried, ground, and sieved, and then mixed with a graphene derivative in a certain proportion to serve as a carbon source carrier. Water, oxygen-containing weak acid, reducing agent, and basic carbonate are fully mixed to prepare a metal aqueous solution, and the metal aqueous solution is slowly added to the carbon source carrier under the action of an ultrasonic cell crusher to prepare a uniformly dispersed carbon metal solution. The uniformly dispersed carbon metal solution is mixed with a certain concentration of sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor, the catalyst precursor after the hydrothermal reaction is centrifuged and washed, and then the obtained filter cake is heat-treated in a suspension oven to prepare a marine biomass desulfurization catalyst.

[0009] Generally, the marine biomass can be one or more of Enteromorpha, Zostera marina, Laminaria japonica, and Gramineae balsamifera. The pretreatment is to clean the mud and sand on the surface of the marine biomass with clean water, and then cut it into 5-10 cm small segments and put it into an ultrasonic washing machine for ultrasonic fine washing.

[0010] Generally, the mass ratio of the marine biomass to the graphene derivative is 1:0.1-0.3.

[0011] Generally, the oxygen-containing weak acid is one or more of formic acid, carbonic acid, hypochlorous acid and hydrofluoric acid, the reducing agent can be one or more of potassium borohydride, sodium borohydride and ethanol, the basic carbonate can be one of basic copper carbonate, basic zinc carbonate and basic nickel carbonate, and the basic carbonate serves as a metal source.

[0012] Generally, the mass ratio of water, oxygen-containing weak acid, reducing agent and basic carbonate in the metal aqueous solution is 1:1:0.1:1-5.

[0013] Generally, the power of the ultrasonic crusher is 100-300 W, and the time is 30-90 min.

[0014] Generally, the ratio of the metal aqueous solution to the carbon source carrier is 1:1-3.

[0015] Generally, the concentration of sodium hydroxide is 2 mol / L, and the ratio of carbon metal solution to sodium hydroxide is 1:2-5.

[0016] Generally, the temperature of the hydrothermal synthesis reactor is 150-250° C., and the time is 90-180 min.

[0017] Generally, the rotation speed of the centrifugal washing is 5000-10000 r / min, and the time is 10-15 min.

[0018] Generally, the heat treatment temperature is 200-500° C. and the time is 1-5 h. Beneficial Effects

[0019] (1) The catalyst prepared by the present invention mainly uses marine biomass as a porous carbon carrier, which is cheap, easy to obtain, and green and environmentally friendly compared to traditional porous carbon materials such as polyacrylonitrile and polyethylene glycol.

[0020] (2) The desulfurization catalyst is made into a nanowire morphology through a hydrothermal synthesis method. It has a small degree of metal aggregation, a large number of metal active centers per unit area, a large metal dispersion, and good adsorption desulfurization performance. Implementation

[0021] The following examples are used to further illustrate the content of the present invention. The following examples are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention. Example 1

[0022] Enteromorpha and Zostera marina were pretreated by washing with water and ultrasonic fine washing. The pretreated Enteromorpha and Zostera marina were dried, ground and sieved. A mixture of 10 g of the treated Enteromorpha and Zostera marina was mixed with 1 g of graphene derivatives to serve as a carbon source carrier. 5 g of formic acid, 0.5 g of potassium borohydride and 5 g of basic copper carbonate were slowly added to 5 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 300 W ultrasonic cell crusher, 10 g of the metal aqueous solution was slowly added to 10 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution. The ultrasonic crushing time was 30 min. 15 g of the uniformly dispersed carbon metal solution was mixed with 30 g of 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 150 ° C and the time was 90 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed at a speed of 5000 r / min for 10 min, and then the obtained filter cake was placed in a suspension oven and heat treated at 200°C for 1 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S1.

[0023] Example 2 Enteromorpha and Laminaria japonica were pretreated by washing with water and ultrasonic fine washing. The pretreated Enteromorpha and Laminaria japonica were dried, ground and sieved. A mixture of 20 g of the treated Enteromorpha and Laminaria japonica was mixed with 4 g of graphene derivatives to serve as a carbon source carrier. 5 g of carbonic acid, 0.5 g of sodium borohydride and 10 g of basic zinc carbonate were slowly added to 5 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 100 W ultrasonic cell crusher, 10 g of the metal aqueous solution was slowly added to 20 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution. The ultrasonic crushing time was 60 min. 10 g of the uniformly dispersed carbon metal solution was mixed with 30 g of 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 150 ° C and the time was 90 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed at a speed of 8000 r / min for 10 min, and then the obtained filter cake was placed in a suspension oven and heat treated at 300°C for 2 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S2.

[0024] Example 3 The two marine biomasses, kelp and sedge, were rinsed with clean water and pretreated with ultrasonic fine washing. The pretreated kelp and sedge were dried, ground and sieved. A mixture of 15 g of the treated kelp and sedge was mixed with 1.5 g of graphene derivatives to serve as a carbon source carrier. 5 g of a mixture of carbonic acid and hypochlorous acid, 0.5 g of ethanol, and 15 g of basic zinc carbonate were slowly added to 5 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 200 W ultrasonic cell crusher, 10 g of the metal aqueous solution was slowly added to 20 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution, and the ultrasonic crushing time was 60 min. 10 g of the uniformly dispersed carbon metal solution was mixed with 40 g, 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 200℃ and the time was 90 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed for 15 min at a speed of 10000 r / min, and then the obtained filter cake was placed in a suspension oven and heat treated at 400 °C for 5 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S3.

[0025] Example 4 Enteromorpha, a marine biomass, was rinsed with clean water and pretreated with ultrasonic fine washing. The pretreated Enteromorpha was dried, ground and sieved. A mixture of 20 g of treated kelp and dragon's beard grass was mixed with 6 g of graphene derivatives to serve as a carbon source carrier. 15 g of hydrofluoric acid, 1.5 g of ethanol and 60 g of basic nickel carbonate were slowly added to 15 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 300 W ultrasonic cell crusher, 5 g of the metal aqueous solution was slowly added to 15 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution. The ultrasonic crushing time was 90 min. 10 g of the uniformly dispersed carbon metal solution was mixed with 50 g of 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 250°C and the time was 150 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed for 15 min at a speed of 10000 r / min, and then the obtained filter cake was placed in a suspension oven and heat treated at 500°C for 4 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S4.

[0026] Example 5 The marine biomass, kelp, was rinsed with clean water and pretreated with ultrasonic fine washing. The pretreated kelp was dried, ground and sieved. 20 g of the treated kelp was mixed with 4 g of graphene derivatives to serve as a carbon source carrier. 15 g of a mixture of formic acid and hydrofluoric acid, 1.5 g of a mixture of potassium borohydride and sodium borohydride, and 30 g of basic nickel carbonate were slowly added to 15 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 300 W ultrasonic cell crusher, 10 g of the metal aqueous solution was slowly added to 20 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution. The ultrasonic crushing time was 90 min. 10 g of the uniformly dispersed carbon metal solution was mixed with 50 g, 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 200 ° C and the time was 180 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed at a speed of 8000 r / min for 15 min, and then the obtained filter cake was placed in a suspension oven and heat treated at 500°C for 2 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S5.

[0027] Example 6 Two marine biomasses, Zostera marina and Dracaena gracilis, were pretreated by water washing and ultrasonic fine washing. The Zostera marina and Dracaena gracilis were dried, ground and sieved after pretreatment. 20 g of the treated Zostera marina and Dracaena gracilis were mixed with 2 g of graphene derivatives to serve as carbon source carriers. 10 g of carbonic acid, 1 g of potassium borohydride and sodium borohydride mixture, and 50 g of basic copper carbonate were slowly added to 10 g of deionized water and mixed thoroughly to prepare a metal aqueous solution. Under the action of a 150 W ultrasonic cell crusher, 10 g of the metal aqueous solution was slowly added to 20 g of the carbon source carrier to prepare a uniformly dispersed carbon metal solution, and the ultrasonic crushing time was 90 min. 10 g of the uniformly dispersed carbon metal solution was mixed with 30 g, 2 mol / L sodium hydroxide and placed in a hydrothermal synthesis reactor to react to obtain a catalyst precursor. The hydrothermal synthesis reaction temperature was 200℃ and the time was 120 min. The catalyst precursor after the hydrothermal reaction was centrifugally washed at a speed of 8000 r / min for 10 min, and then the obtained filter cake was placed in a suspension oven and heat treated at 300°C for 3 h to prepare a marine biomass desulfurization catalyst. The obtained catalyst was recorded as S6. Comparative Example 1

[0028] Accurately weigh 10 g of polyethylene glycol and 10 g of nickel acetate tetrahydrate, grind for about half an hour until there are no obvious large particles, and then heat treat the obtained sample in a tube furnace, heat to 400°C under a nitrogen atmosphere and keep it for 4 hours. After cooling, the obtained catalyst is recorded as R1. Comparative Example 2

[0029] Accurately weigh 10 g of polyacrylonitrile and 15 g of nickel acetate tetrahydrate, grind for about half an hour until there are no obvious large particles, and then heat treat the obtained sample in a tube furnace, heat to 300°C under a nitrogen atmosphere and maintain for 4 hours. After cooling, the obtained catalyst is recorded as R2. Sample testing

[0030] The present invention prepares the model oil by dissolving thiophene in n-octane, with a sulfur concentration of 50 ppm. The reaction is carried out in a fixed bed, and 1 g of the catalyst is placed in the optimal temperature region of a stainless steel tube, with both the upper and lower parts filled with quartz sand. Before the adsorption experiment, the adsorbent is treated with reducing gas H 2 The reduction was carried out at 400 °C at a flow rate of 30 mL / min for 4 h. After the adsorbent was reduced, n-octane containing simulated sulfur flowed into the adsorber for adsorption desulfurization reaction. Test samples were collected from the outlet flow at fixed time intervals. When the sulfur content in the test sample was greater than 1 ppm, the total test time was the breakthrough time of the catalyst; when the sulfur content in the test sample reached 50 ppm, the total desulfurization amount of the catalyst was the saturated adsorption capacity of the catalyst.

[0031] The test results of the samples are shown in Table 1, wherein samples S1-S6 are prepared by the method of the present invention, and samples R1 and R2 are reference samples.

[0032] Table 1 Catalyst specific surface area and pore volume data

[0033] Table 2 Catalyst adsorption desulfurization performance

[0034] As can be seen from Table 1, compared with the catalyst prepared by solid grinding method using polymer as porous carbon material, the morphology of the catalyst made into nanowires by hydrothermal synthesis method using marine biomass as porous carbon material has larger mesoporous specific surface area and mesoporous pore volume. And according to the literature, metal is the active center of adsorption desulfurization, larger mesoporous specific surface area and larger mesoporous pore volume will make it difficult for metal to gather, the metal has high dispersion, and has more metal active centers. At the same time, it can be seen from Table 2 that the marine biomass desulfurization catalyst prepared by the method of the present invention has a breakthrough time and saturated adsorption capacity higher than the reference catalyst. This is mainly due to the small degree of metal aggregation, many active centers and large dispersion of the catalyst sample prepared by the present invention. At the same time, marine biomass such as Enteromorpha is a natural porous carbon material, which is cheap and easy to obtain, rich in species, and has higher economic benefits than polymer carbon materials.

[0035] It should be noted that the above is only a preferred embodiment of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A marine biomass desulfurization catalyst, characterized in that The catalyst contains a carbon source carrier made of marine biomass and a metal active component, and the mass ratio of the metal active component to the carbon source carrier is 1:1-3; the mesopore specific surface area and mesopore volume of the catalyst are 85-100 m 2 / g, 0.150~0.170 cm 3 / g.

2. The method for preparing the marine biomass desulfurization catalyst according to claim 1, characterized in that The desulfurization catalyst uses marine biomass as a carbon source carrier, slowly adds a metal aqueous solution into the carbon source carrier to prepare a uniformly dispersed carbon metal solution, and then uses a hydrothermal synthesis method to prepare the marine biomass desulfurization catalyst.

3. The method for preparing the marine biomass desulfurization catalyst according to claim 2, characterized in that The marine biomass is first pretreated, and the pretreated marine biomass is dried, ground, sieved, and then mixed with a graphene derivative to obtain a carbon source carrier; water, oxygen-containing weak acid, reducing agent, and basic carbonate are fully mixed to prepare a metal aqueous solution, and the metal aqueous solution is added to the carbon source carrier under the action of an ultrasonic cell crusher to prepare a uniformly dispersed carbon metal solution; the uniformly dispersed carbon metal solution is mixed with sodium hydroxide, and a catalyst precursor is obtained through a hydrothermal synthesis reaction, the catalyst precursor is centrifuged and washed, and then the obtained filter cake is heat-treated to prepare a marine biomass desulfurization catalyst.

4. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The marine biomass is one or more of Enteromorpha, Zostera marina, Laminaria japonica, and Gramineae chinensis. The pretreatment is to clean the mud and sand on the surface of the marine biomass with clean water, and then cut it into small sections of 5 to 10 cm and put it into an ultrasonic washing machine for ultrasonic fine washing.

5. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The mass ratio of marine biomass to graphene derivatives is 1:0.1~0.

3.

6. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The oxygen-containing weak acid is one or more of formic acid, carbonic acid, hypochlorous acid and hydrofluoric acid; the reducing agent is one or more of potassium borohydride, sodium borohydride and ethanol; the basic carbonate is one of basic copper carbonate, basic zinc carbonate and basic nickel carbonate; and the basic carbonate is a metal source.

7. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The mass ratio of water, oxygen-containing weak acid, reducing agent and basic carbonate in the metal aqueous solution is 1:1:0.1:1~5.

8. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The power of the ultrasonic crusher is 100~300 W, and the time is 30~90 min.

9. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The mass ratio of the metal aqueous solution to the carbon source carrier is 1:1~3.

10. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The concentration of sodium hydroxide is 2 mol / L, and the mass ratio of carbon metal solution to sodium hydroxide is 1:2~5.

11. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The temperature of the hydrothermal synthesis reaction is 150~250℃, and the time is 90~180 min.

12. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The speed of centrifugal washing is 5000~10000 r / min, and the time is 10~15 min.

13. The method for preparing the marine biomass desulfurization catalyst according to claim 3, characterized in that The heat treatment temperature is 200~500℃ and the time is 1~5 h.

Images