Rock asphalt-based porous carbon spherical particles and preparation method thereof

Abstract

The invention provides rock asphalt-based porous carbon spherical particles and a preparation method thereof, and the method comprises the following steps: uniformly mixing rock asphalt-based porous carbon powder with an asphalt tetrahydrofuran solution, and volatilizing tetrahydrofuran to obtain mixed powder; uniformly mixing the mixed powder with sodium alginate hydrogel, and granulating to obtain spherical particles; drying and carbonizing the spherical particles to obtain carbonized spherical particles; soaking the carbonized spherical particles in a KOH aqueous solution, standing, drying, and performing high-temperature activation to obtain activated spherical particles; and performing acid pickling, water washing and drying on the activated spherical particles to obtain the rock asphalt-based porous carbon spherical particles. The preparation method is simple, the condition is mild, the process is easy to control, the operation is convenient, the cost is low, and the prepared rock asphalt-based porous carbon spherical particles have higher specific surface area and adsorption capacity, are easier to recover compared with a powder porous carbon adsorbent, and have a better industrial production prospect.

Description

Technical Field

[0001] The present invention relates to the field of high-value application materials of non-traditional non-metallic minerals. Specifically, it relates to a porous carbon spherical particle based on rock asphalt and a preparation method thereof. Background Art

[0002] Natural solid asphalt is a solid carbonaceous non-metallic mineral resource formed by a series of complex physical and chemical processes such as thermal alteration, deasphalting, and biodegradation of organic fluids rich in hydrocarbons and their non-metallic derivatives under geological actions. With the development of modern analysis techniques, especially in-situ mineralogical analysis techniques such as scanning electron microscopy and spectroscopy, and organic geochemistry, people's understanding of the characteristics of natural solid asphalt has been gradually revealed. However, the common problems in the development and utilization of natural solid asphalt at home and abroad currently are the lack of in-depth understanding of the genetic mechanism, evolution process, structure, and properties. Due to its complex structure and large development and utilization difficulties, etc., the application of natural solid asphalt in new materials, chemical engineering, and other fields outside road construction needs to be further explored.

[0003] In the late 1990s, Academician Zhao Pengda proposed and initially established the theoretical system of "non-traditional mineral resources". In 1998, six academicians including Zhao Pengda and Tu Guangchi issued an academician initiative letter titled "Strengthening the Research on Non-traditional Mineral Resources", believing that the cognition, discovery, development, and utilization of non-traditional mineral resources are forward-looking and strategic tasks. The hard natural solid asphalt in the Longmenshan area in the northwest of Sichuan (northwestern Sichuan) is of the origin of crude oil thermal cracking, with characteristics such as high oxidation degree, rich polar functional groups and active groups (carboxyl group, carbonyl group, aldehyde group, naphthalene, etc.) promoting crosslinking and polymerization, and a relatively high softening point of 230 - 300 °C. Therefore, it is difficult to be directly used as road asphalt and is mainly used as a modifier and additive for asphalt mixtures. The natural solid asphalt in northwestern Sichuan is the main distribution area of natural asphalt in China. Only the identified resource volume of three natural asphalt ore bodies in Guangyuan area is about 100 million tons (about 11 million tons of asphalt), but its overall exploration and development and utilization level is low. It belongs to a typical non-traditional (compared with petroleum and graphite minerals) non-metallic mineral resource, and there is an urgent need to strengthen the research on geological basic theories and methods to explore new ways for its high-value utilization. Therefore, under the background of the country's promotion of a new round of strategic actions for prospecting breakthroughs, it is of great significance to carry out research work on the key basic scientific issues related to the development and utilization of natural asphalt ore in northwestern Sichuan.

[0004] With the need for global green, low-carbon and sustainable development, porous carbon has attracted the interest of scientists due to its disordered-ordered carbonaceous network structure composed of interconnected or closed pores, large specific surface area, low density, high thermal conductivity, corrosion resistance and structural stability, and also combines the advantages of carbon materials. Nowadays, porous carbon has been widely used in emerging fields such as new energy and ecological environmental protection, demonstrating its huge application potential and value. There are a wide variety of raw materials for preparing porous carbon materials, mainly including biomass materials, polymer materials, tar, coal and asphalt, etc. Natural asphalt is rich in polycyclic aromatic hydrocarbons, and due to its high carbon content, high reactivity and rich resources, it is usually used as a precursor for preparing carbon materials and is suitable for preparing porous carbon. However, at present, most porous carbon materials are in powder form. When used as adsorbents, there are problems such as difficulty in separating from solvents after adsorption, large specific resistance during filtration separation, and incomplete filtration. To improve the above deficiencies, the present invention successfully prepares a spherical rock asphalt-based porous carbon particle with a high specific surface area and adsorption capacity. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies existing in the prior art. For example, one of the purposes of the present invention is to provide a preparation method of spherical rock asphalt-based porous carbon particles; the second purpose of the present invention is to provide spherical rock asphalt-based porous carbon particles.

[0006] To achieve the above purpose, on the one hand, the present invention provides a preparation method of spherical rock asphalt-based porous carbon particles, and the method includes the following steps:

[0007] 1) Mix the spherical rock asphalt-based porous carbon powder evenly with the asphalt tetrahydrofuran solution, and obtain a mixed powder after the tetrahydrofuran volatilizes;

[0008] 2) Mix the mixed powder evenly with the sodium alginate hydrogel, granulate, and obtain spherical particles;

[0009] 3) Dry and carbonize the spherical particles to obtain carbonized spherical particles;

[0010] 4) Immerse the carbonized spherical particles in an aqueous KOH solution and let them stand, dry them and then carry out high-temperature activation to obtain activated spherical particles;

[0011] 5) After pickling, washing with water and drying the activated spherical particles, obtain spherical rock asphalt-based porous carbon particles.

[0012] Optionally, the spherical rock asphalt-based porous carbon powder is prepared from rock asphalt, and the rock asphalt includes purified rock asphalt; the specific surface area of the spherical rock asphalt-based porous carbon powder is greater than 2000m 2 / g.

[0013] Optionally, the mass ratio of the rock asphalt-based porous carbon powder to the asphalt in the asphalt tetrahydrofuran solution is (1-3):1; the ratio of the rock asphalt-based porous carbon powder to the sodium alginate hydrogel is 1 g: 6-10 ml.

[0014] Optionally, the asphalt tetrahydrofuran solution is prepared by adding purified rock asphalt to a tetrahydrofuran solution and stirring at 40-50 °C and a rotation speed of 200-400 rmp for 3-5 h; the concentration of the asphalt tetrahydrofuran solution is 100-150 g / L.

[0015] Optionally, the sodium alginate hydrogel is prepared by adding sodium alginate to water and stirring at 15-35 °C and a rotation speed of 200-600 rmp for 4-6 h;

[0016] The water includes ultrapure water; the concentration of the sodium alginate hydrogel is 50-80 g / L.

[0017] Optionally, the method for preparing the carbonized spherical particles is to place the spherical particles in a 2 constant temperature tubular furnace under N atmosphere and obtain them by calcination.

[0018] The temperature for drying is 80-105 °C, and the drying time is 10-12 h; the temperature for constant temperature is 300-500 °C, the heating rate is 5 °C / min, and the N 2 flow rate is 0.4 L / min; the calcination time is 0.5-2 h.

[0019] Optionally, the standing time in step 4) is 30-60 min; the drying temperature is 80-105 °C, and the drying time is 10-12 h;

[0020] The concentration of the KOH aqueous solution is 1 mol / L; the mass ratio of the carbonized spherical particles to KOH is (0.5-2):1.

[0021] Optionally, the high-temperature activation is to place the carbonized spherical particles mixed with KOH in a 2 constant temperature tubular furnace under N atmosphere and obtain them by calcination.

[0022] The temperature for constant temperature is 700-900 °C, the heating rate is 5 °C / min, and the N 2 flow rate is 0.4 L / min; the calcination time is 0.5-2 h.

[0023] Optionally, the pickling in step 5) is carried out by soaking in an HCl solution, the concentration of the HCl solution is 1 mol / L, and the soaking time is 2-4 h;

[0024] The water washing is carried out with ultrapure water until it is neutral; the drying temperature is 80 - 105 °C, and the drying time is 10 - 12 h.

[0025] On the other hand, the present invention provides a spherical rock asphalt-based porous carbon particle, which can be prepared by the above method.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0027] (1) The present invention uses rock asphalt-based porous carbon powder and sodium alginate hydrogel as raw materials, thus having a relatively high specific surface area and adsorption capacity, and can directly adsorb pollutants such as methylene blue and tetracycline in water.

[0028] (2) The present invention adds purified rock asphalt to the raw materials of the spherical rock asphalt-based porous carbon particle. Since the purified rock asphalt softens during the carbonization process and jointly constitutes the skeleton of the spherical rock asphalt-based porous carbon particle with sodium alginate, the compressive strength of the spherical rock asphalt-based porous carbon particle can be increased.

[0029] (3) The spherical rock asphalt-based porous carbon particle prepared by the present invention has a relatively high specific surface area (1000 - 2000 m 2 / g) and adsorption capacity.

[0030] (4) The preparation method of the present invention is simple, the conditions are mild, the process is simple and easy to control, the operation is convenient, the cost is low, and it is easier to recover than the powder porous carbon adsorbent, and has a good industrial production prospect, providing a method for the high-value utilization of natural solid asphalt. Description of the Drawings

[0031] Through the following description in conjunction with the drawings / tables, the above and other objects and / or features of the present invention will become clearer, wherein:

[0032] Figure 1 Shows the external shape diagram of the spherical rock asphalt-based porous carbon particle prepared by the present invention;

[0033] Figure 2 Shows the scanning electron microscope image of the spherical rock asphalt-based porous carbon particle prepared by the present invention;

[0034] Figure 3 Shows the scanning electron microscope image of the surface of the spherical rock asphalt-based porous carbon particle prepared by the present invention;

[0035] Figure 4 Shows another scanning electron microscope image of the surface of the spherical rock asphalt-based porous carbon particle prepared by the present invention;

[0036] Figure 5 Shows the XRD diagram of the spherical rock asphalt-based porous carbon particle prepared by the present invention;

[0037] Figure 6 The FTIR diagram of the spherical particles of rock asphalt-based porous carbon prepared by the present invention is shown;

[0038] Figure 7 The pore size distribution curve diagram of the spherical particles of rock asphalt-based porous carbon prepared by the present invention is shown;

[0039] Figure 8 The adsorption and desorption curve diagram of the spherical particles of rock asphalt-based porous carbon prepared by the present invention is shown;

[0040] Figure 9 The performance diagram of the spherical particles of rock asphalt-based porous carbon prepared by the present invention for adsorbing methylene blue is shown. Detailed implementation manners

[0041] In the following, a spherical particle of rock asphalt-based porous carbon and a preparation method thereof according to the present invention will be described in detail with reference to exemplary embodiments.

[0042] Exemplary embodiment 1

[0043] This exemplary embodiment provides a preparation method of spherical particles of rock asphalt-based porous carbon, and the method includes the following steps:

[0044] S1. Mix the rock asphalt-based porous carbon powder evenly with the asphalt tetrahydrofuran solution, and obtain a mixed powder after the tetrahydrofuran volatilizes.

[0045] In this embodiment, the rock asphalt-based porous carbon powder is prepared from rock asphalt, and the rock asphalt includes purified rock asphalt; the specific surface area of the rock asphalt-based porous carbon powder is greater than 2000m 2 / g.

[0046] Introducing purified rock asphalt into the raw material of the rock asphalt-based porous carbon powder, during the heating process, due to its softening and connection, the formed skeleton of the spherical particles of rock asphalt-based porous carbon can increase its compressive strength.

[0047] In this embodiment, the mass ratio of the rock asphalt-based porous carbon powder to the asphalt in the asphalt tetrahydrofuran solution is (1-3):1 (such as 1.1:1, 1.4:1, 1.7:1, 2:1, 2.5:1, and 2.9:1, etc.).

[0048] In this embodiment, the asphalt tetrahydrofuran solution is prepared by adding purified rock asphalt into the tetrahydrofuran solution and stirring for 3 - 5 h (such as 3.1 h, 3.5 h, 3.8 h, 4.5 h, and 4.9 h, etc.) at a temperature of 40 - 50 °C (such as 41 °C, 44 °C, 45 °C, and 49 °C, etc.) and a rotation speed of 200 - 400 rmp (such as 210 rmp, 250 rmp, 280 rmp, 300 rmp, 350 mp, and 390 rmp, etc.); the concentration of the asphalt tetrahydrofuran solution is 100 - 150 g / L (such as 101 g / L, 110 g / L, 125 g / L, 138 g / L, and 149 g / L, etc.).

[0049] S2. Mix the mixed powder and the sodium alginate hydrogel evenly and granulate to obtain spherical particles.

[0050] In this embodiment, the ratio of the rock asphalt-based porous carbon powder to the sodium alginate hydrogel is 1 g : 6 - 10 ml (such as 1 g : 6.1 ml, 1 g : 7 ml, 1 g : 8.5 ml, and 1 g : 9.8 ml, etc.).

[0051] In this embodiment, the sodium alginate hydrogel is prepared by adding sodium alginate into water and stirring for 4 - 6 h (such as 4.1 h, 4.3 h, 4.8 h, 5.5 h, and 5.9 h, etc.) at a temperature of 15 - 35 °C (such as 16 °C, 20 °C, 27 °C, and 34 °C, etc.) and a rotation speed of 200 - 600 rmp (such as 210 rmp, 350 rmp, 410 rmp, 480 rmp, 550 mp, and 590 rmp, etc.).

[0052] In this embodiment, the water includes ultrapure water; the concentration of the sodium alginate hydrogel is 50 - 80 g / L (such as 51 g / L, 55 g / L, 64 g / L, 72 g / L, and 79 g / L, etc.).

[0053] S3. Dry and carbonize the spherical particles to obtain carbonized spherical particles.

[0054] In this embodiment, the preparation method of the carbonized spherical particles is to place the dried spherical particles in a nitrogen 2 atmosphere tube furnace and obtain them by constant temperature calcination.

[0055] In this embodiment, the drying temperature is 80 - 105 °C (such as 81 °C, 95 °C, 100 °C, and 105 °C, etc.), and the drying time is 10 - 12 h (such as 10.1 h, 10.4 h, 10.7 h, 11 h, and 11.9 h, etc.); the constant temperature is 300 - 500 °C (such as 310 °C, 355 °C, 400 °C, and 490 °C, etc.), the heating rate is 5 °C / min, and nitrogen 2The flow rate is 0.4 L / min; the calcination time is 0.5 - 2 h (such as 0.5 h, 0.6 h, 1.2 h, 1.7 h, and 1.9 h, etc.).

[0056] S4. Immerse the carbonized spherical particles in an aqueous KOH solution and let them stand still. After drying, conduct high-temperature activation to obtain activated spherical particles.

[0057] In this embodiment, the purpose of immersing the carbonized spherical particles in the aqueous KOH solution is to uniformly fill the pores of the particles with KOH. In addition to using KOH, various activators such as K 2 CO 3 can also be used.

[0058] In this embodiment, the standing time is 30 - 60 min (such as 31 min, 35 min, 46 min, 51 min, and 59 min, etc.); the drying temperature is 80 - 105 °C (such as 81 °C, 92 °C, 100 °C, and 105 °C, etc.), and the drying time is 10 - 12 h (such as 10.1 h, 10.2 h, 10.6 h, 11 h, and 11.9 h, etc.).

[0059] Among them, in order to avoid damaging the particle morphology, the method of standing still is adopted to uniformly fill the pores of the particles with KOH.

[0060] In this embodiment, the concentration of the aqueous KOH solution is 1 mol / L; the mass ratio of the carbonized spherical particles to KOH is (0.5 - 2):1 (such as 0.6:1, 0.8:1, 1.2:1, 1.5:1, and 1.9:1, etc.).

[0061] In this embodiment, the high-temperature activation is obtained by placing the carbonized spherical particles mixed with KOH in a N 2 atmosphere tube furnace and conducting isothermal calcination.

[0062] In this embodiment, the isothermal temperature is 700 - 900 °C (such as 710 °C, 792 °C, 800 °C, 820 °C, and 890 °C, etc.), the heating rate is 5 °C / min, and the N 2 flow rate is 0.4 L / min; the calcination time is 0.5 - 2 h (such as 0.6 h, 0.8 h, 1.2 h, 1.7 h, and 1.9 h, etc.).

[0063] S5. After pickling, washing with water, and drying the activated spherical particles, rock asphalt-based porous carbon spherical particles are obtained.

[0064] In this embodiment, the pickling is carried out by soaking in an HCl solution. The concentration of the HCl solution is 1 mol / L, and the soaking time is 2 - 4 h (such as 2.1 h, 2.5 h, 3.3 h, 3.6 h, and 3.9 h, etc.).

[0065] Among them, the purpose of pickling is to remove the excess KOH.

[0066] In this embodiment, the water washing is carried out with ultrapure water until neutral; the drying temperature is 80-105 °C, and the drying time is 10-12 h (such as 10.1 h, 10.3 h, 10.6 h, 11.2 h, and 11.9 h, etc.).

[0067] Among them, using rock asphalt-based porous carbon powder and sodium alginate hydrogel as raw materials to prepare rock asphalt-based porous carbon spherical particles can have a relatively high specific surface area and adsorption capacity.

[0068] Exemplary Embodiment 2

[0069] This exemplary embodiment provides a rock asphalt-based porous carbon spherical particle, and the rock asphalt-based porous carbon spherical particle can be prepared by the method described in Exemplary Embodiment 1.

[0070] To better understand the above exemplary embodiments, further description will be given below in conjunction with specific examples.

[0071] Example 1

[0072] (I) Preparation of rock asphalt-based porous carbon spherical particles

[0073] (1) Preparation of rock asphalt-based porous carbon powder: Grind 3 g of purified rock asphalt, 18 g of Mg(OH) 2 and 18 g of KOH evenly and place them in a crucible boat. In a tube furnace, calcine at 370 °C for 1 h and then at 800 °C for 2 h (heating rate 5 °C / min, N 2 flow rate is 0.4 L / min). After cooling to room temperature, take it out, soak it in 2 mol / L dilute hydrochloric acid for 4 h, and then wash it with ultrapure water until neutral to obtain about 0.6 g of powdery rock asphalt-based porous carbon powder. The specific surface area of this activated carbon powder is greater than 2000 m 2 / g.

[0074] (2) Preparation of rock asphalt tetrahydrofuran solution: Add 3 g of purified rock asphalt to 20 ml of tetrahydrofuran solution, and stir at 50 °C and 400 rmp for 5 h to obtain a rock asphalt tetrahydrofuran solution with a concentration of 150 g / L.

[0075] (3) Preparation of sodium alginate hydrogel: Add 7.5 g of sodium alginate to 100 ml of ultrapure water, and stir at 25 °C and 200-600 rmp for 6 h to obtain a sodium alginate hydrogel with a concentration of 75 g / L.

[0076] (4) Preparation of rock asphalt-based porous carbon spherical particles:

[0077] Weigh 1.5 g of rock asphalt-based porous carbon powder and place it in a 25 mL beaker. Add 10 mL of rock asphalt tetrahydrofuran solution in the fume hood, mix evenly. After the tetrahydrofuran volatilizes, a mixed powder is obtained. Then add 10 mL of sodium alginate hydrogel, stir evenly, and use a pill-making machine to make spherical particles about 3 mm in diameter;

[0078] Place the spherical particles in an oven at 100 °C for 10 h to dry, and then place them in a 2 atmospheric tube furnace and calcine at a constant temperature of 370 °C for 1 h, with a heating rate of 5 °C / min and a 2 flow rate of 0.4 L / min to obtain carbonized spherical particles;

[0079] Immerse the carbonized spherical particles in a 1 mol / L KOH aqueous solution, with a mass ratio of carbonized spherical particles to KOH of 2:1. After standing for 30 min, place them in an oven at 100 °C for 4 h to dry. After drying, place them in a 2 atmospheric tube furnace and calcine at a constant temperature of 800 °C for 2 h for activation to obtain activated spherical particles, with a heating rate of 5 °C / min and a 2 flow rate of 0.4 L / min.

[0080] Immerse the activated spherical particles in a 1 mol / L HCl solution for 4 h, then wash them with ultrapure water until neutral. Then place the activated spherical particles in an oven at 100 °C for 10 h to dry to obtain the rock asphalt-based porous carbon spherical particles HC 1-2 .

[0081] (2) Result discussion

[0082] (1) Measure the external dimensions of the prepared HC 1-2 . The external view is as shown in Figure 1 . It can be seen from the figure that the spherical particles HC 1-2 have a relatively uniform appearance, and the particle size is about 3 mm.

[0083] (2) Observe the microstructure of the prepared HC 1-2 by SEM. As shown in Figures 2 - 4 , among them, Figure 2 Figure b in is the enlarged view of Figure 2 Figure a in, Figure 3 Figure b in is the enlarged view of Figure 3 Figure a in, Figure 4 Figure b in is the enlarged view of Figure 4 Figure a in. It can be seen from the figure that the spherical particles HC 1-2 have well-developed pores. Under the action of porous carbon powder, purified rock asphalt and sodium alginate in the raw materials, cross-linking occurs to form a stable spherical particle shape; at the same time, the hierarchical porous structure of the porous carbon powder is maintained, realizing a multi-level pore structure - this structure can be verified by Table 1 and Figure 7 .

[0084] (3) The prepared HC 1-2 was subjected to XRD testing, and the test results are as Figure 5 shown. It can be seen from the figure that the spherical particle HC 1-2 constitutes a broad peak near 2θ = 20.82° and 2θ = 26° together, and also constitutes a broad peak near 2θ = 43°. 2θ = 20.82° and 2θ = 26° are respectively related to the broad peaks of the 101 crystal plane of graphene and the (0 0 2) crystal plane of the graphite structure, and the broad peak near 43° is related to the (1 0 0) of the graphite structure and the 103 crystal plane of graphene. This indicates that HC 1-2 is mainly composed of amorphous carbon and has a disordered non-graphite structure and a partial graphene structure.

[0085] (4) The prepared HC 1-2 was subjected to FT-IR testing, and the test results are as Figure 6 shown. It can be seen from the figure that the spherical particle HC 1-2 shows characteristic peaks at 3434 cm -1 , 1350 cm -1 and 758 cm -1 , corresponding to the stretching vibration, single vibration of -OH and; 2923 cm -1 corresponds to the stretching vibration of methylene; 1632 cm -1 is the C=C bond in phenols, proving that the porous carbon is rich in phenolic substances; 1050 cm -1 corresponds to the stretching vibration of C-O in fatty ethers, alcohols / phenols. Therefore, in the porous carbon material, the content of C=C bonds is very rich, and it contains rich hydroxyl groups, providing rich active sites for adsorption.

[0086] (5) The prepared HC 1-2 was subjected to specific surface area and pore size distribution testing, and the test results are shown in Table 1 and Figure 7 shown. It can be seen from Table 1 that the BET specific surface area of the spherical particle HC 1-2 is 1686 m 2 ·g -1 , of which the micropore specific surface area is 725.5 m 2 ·g -1 , accounting for 43%; the total pore volume is 0.8564 cm 3 ·g -1 , and the micropore volume is 0.3005 cm 3 ·g -1 ; the average pore diameter is 3.0010 nm. It can be seen from Figure 7 that the spherical particle HC 1-2 has a hierarchical porous structure of macropores - mesopores - micropores, and the mesopores and micropores below 4 nm have well-developed pores. Therefore, the spherical particle HC1-2 has a high specific surface area and a hierarchical porous structure, as well as Figure 6 the abundant active sites on its surface endow it with good adsorption potential.

[0087] (6) Perform adsorption-desorption tests on the prepared HC 1-2 The test results are as Figure 8 shown. It can be seen from the figure that the adsorption-desorption of spherical particle HC 1-2 conforms to type IV, that is, mesoporous capillary condensation type. When the relative pressure (P / P0) is between 0.4 - 1.0, there is a hysteresis loop, indicating the existence of mesopores. The reason for the generation of the hysteresis loop is that the capillary condensation effect causes the N 2 molecules to condense and fill the mesoporous channels at a pressure lower than atmospheric pressure. Since the capillary condensation starts on the liquid surface of the annular adsorption film on the pore wall, and the desorption starts from the spherical meniscus at the pore mouth, the adsorption and desorption isotherms do not coincide, often forming a hysteresis loop. The rapid adsorption within P / P0 less than 0.01 indicates the existence of a large number of micropores. According to the latest classification of the International Union of Pure and Applied Chemistry (IUPAC), spherical particle HC 1-2 conforms to type H4. The H4-type hysteresis loop is relative to the combination of type I and type II adsorption isotherms. The H4-type appears on adsorbents with a mixture of micropores and mesopores and in solids containing narrow slit pores. Its hysteresis loop isotherm has no obvious saturated adsorption plateau, indicating that the pore structure is very irregular. When the relative pressure is 0.99481, the adsorption capacity can reach 558 cm 3 / g, demonstrating excellent adsorption capacity.

[0088] (7) Apply the prepared HC 1-2 to the adsorption of methylene blue. The results are as Figure 9 shown. It can be seen from the figure that spherical particle HC 1-2 has excellent adsorption capacity for methylene blue. The greater the initial concentration, the greater the equilibrium adsorption capacity. When the initial concentrations are 25, 50, 100, 200, and 300 mg / L respectively, the equilibrium adsorption capacities are 62.81, 124.60, 242.98, 477.55, and 551.99 mg / g respectively; when the initial concentration is less than or equal to 200 mg / L, the adsorption efficiencies at equilibrium adsorption are 95.5% respectively. When the initial concentration is 300 mg / L, the adsorption efficiency at equilibrium adsorption is 73.6%, indicating that spherical particle HC 1-2 is suitable for treating methylene blue with a concentration less than 300 mg / L.

[0089] Although the present invention has been described above in conjunction with exemplary embodiments and the accompanying drawings, those of ordinary skill in the art should clearly understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

[0090] Table 1 Specific surface area and pore size distribution data of rock asphalt-based porous carbon spherical particles HC1-2

[0091]

Claims

1. A method for preparing rock asphalt-based porous carbon spherical particles, characterized in that: The method comprises: 1) mixing the rock asphalt-based porous carbon powder and the asphalt tetrahydrofuran solution uniformly, and obtaining a mixed powder after the tetrahydrofuran is volatilized; 2) mixing the mixed powder and sodium alginate hydrogel uniformly, and granulating to obtain spherical particles; 3) drying and carbonizing the spherical particles to obtain carbonized spherical particles; 4) Soaking the carbonized spherical particles in a KOH aqueous solution and allowing them to stand, drying them, and then performing high-temperature activation to obtain activated spherical particles; 5) The activated spherical particles are acid-washed, water-washed and dried to obtain rock asphalt-based porous carbon spherical particles.

2. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The rock asphalt-based porous carbon powder is prepared from rock asphalt, which includes purified rock asphalt; the specific surface area of ​​the rock asphalt-based porous carbon powder is greater than 2000m 2 / g.

3. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The mass ratio of the rock asphalt-based porous carbon powder to the asphalt in the asphalt tetrahydrofuran solution is (1-3):1; the ratio of the rock asphalt-based porous carbon powder to the sodium alginate hydrogel is 1g:6-10ml.

4. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The asphalt tetrahydrofuran solution is prepared by adding purified rock asphalt into a tetrahydrofuran solution and stirring at 40-50° C. and 200-400 rpm for 3-5 hours; The concentration of the asphalt tetrahydrofuran solution is 100-150 g / L.

5. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The sodium alginate hydrogel is prepared by adding sodium alginate into water and stirring at 15-35° C. and 200-600 rpm for 4-6 hours; The water includes ultrapure water; the concentration of the sodium alginate hydrogel is 50-80 g / L.

6. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The carbonized spherical particles are prepared by drying the spherical particles and then calcining them at a constant temperature in a N2 atmosphere tubular furnace; The drying temperature is 80-105°C, and the drying time is 10-12h; the constant temperature is 300-500°C, the heating rate is 5°C / min, and the N2 flow rate is 0.4L / min; the calcination time is 0.5-2h.

7. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The standing time in step 4) is 30 to 60 minutes; the drying temperature is 80-105°C, and the drying time is 10 to 12 hours; The concentration of the KOH aqueous solution is 1 mol / L; the mass ratio of the carbonized spherical particles to KOH is (0.5-2):

1.

8. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The high temperature activation is achieved by placing carbonized spherical particles mixed with KOH in a N2 atmosphere tube furnace and calcining at a constant temperature; The constant temperature is 700-900°C, the heating rate is 5°C / min, and the N2 flow rate is 0.4L / min; the calcination time is 0.5-2h.

9. The method for preparing rock asphalt-based porous carbon spherical particles according to claim 1, characterized in that: The pickling in step 5) is performed by soaking in HCl solution, the concentration of the HCl solution is 1 mol / L, and the soaking time is 2 to 4 hours; The water washing is performed by using ultrapure water to be washed to neutrality; the drying temperature is 80 to 105° C., and the drying time is 10 to 12 hours.

10. A rock asphalt-based porous carbon spherical particle, characterized in that: The rock asphalt-based porous carbon spherical particles are prepared by the method described in any one of claims 1-9.

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