Preparation method of biomass carbon supported cobalt-based catalyst

Abstract

The present invention discloses a preparation method of a biomass carbon-supported cobalt-based catalyst, comprising: S1, pretreating crab shells by grinding them into powder; S2, soaking the crab shell powder in a mixed solution containing phenolic resin, triblock copolymer and ethanol and then performing heat curing treatment; S3, calcining the heat-cured material at high temperature under N2 atmosphere, and washing and drying after calcination to obtain a biomass carbon material; S4, soaking the biomass carbon material in HNO3 solution for acidification treatment, impregnating the acidified biomass carbon material in a cobalt salt solution and then drying and calcining, and fully grinding to obtain CoO x @BC catalyst. According to the present invention, it can effectively activate persulfate to efficiently remove organic pollutants in water bodies, and the material has stable structure, high catalytic efficiency and high economic benefits, with obvious advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental pollution treatment, and particularly relates to a preparation method of a cobalt-based catalyst supported on biomass carbon. Background Art

[0002] In the past few decades, with the rapid development of modern industry, a large amount of toxic and harmful organic wastewater has been discharged into the water environment of our country, posing a serious threat to human health and ecological safety. So far, a variety of technologies for removing organic pollutants have been developed, such as adsorption, biological treatment, photocatalytic degradation, electrochemical oxidation technology, and advanced oxidation technology (AOPs).

[0003] Persulfate (PMS) itself has a certain oxidation ability, but its oxidation ability is limited. Therefore, recent research has mainly focused on exploring effective methods for activating PMS. Currently, methods for activating PMS to degrade organic matter include heating, alkali, ultraviolet light, ultrasonic waves, electrochemistry, transition metals, carbon materials, etc. Among them, transition metals are considered the most convenient way to activate PMS, which is more economical, efficient, and does not require external energy input. Various transition metal ions can effectively activate PMS, such as Fe 2+ , Mn 2+ , Ni 2+ , and Co 2+ etc. Among many transition metal catalysts, cobalt-based catalysts are considered to be the catalysts with the highest activity for activating PMS, but there are some drawbacks, such as the leaching problem of toxic metal ions and easy agglomeration. As a typical non-metallic catalyst, carbonaceous materials have a high specific surface area, rich oxygen-containing functional groups, and high electron transfer ability. Although they have a certain activation performance for PMS, their activation effect is poor. Summary of the Invention

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a preparation method of a cobalt-based catalyst supported on biomass carbon, which can effectively activate persulfate to efficiently remove organic pollutants in water, with stable material structure, high catalytic efficiency, and high economic benefits, and has obvious advantages. To achieve the above-mentioned purpose and other advantages according to the present invention, a preparation method of a cobalt-based catalyst supported on biomass carbon is provided, including:

[0005] S1. Pretreat the crab shell and grind it into powder;

[0006] S2. Immerse the crab shell powder in a mixed solution containing phenolic resin, triblock copolymer, and ethanol, and then perform thermal curing treatment;

[0007] S3. Calcinate the thermally cured material at high temperature in an N2 atmosphere, and after calcination, wash and dry it to obtain a biomass carbon material;

[0008] S4. Immerse the biomass carbon material in an HNO3 solution for acidification treatment. After acidification, impregnate the biomass carbon material in a cobalt salt solution and then dry and calcine it. Grind it thoroughly to obtain CoO. x @BC catalyst.

[0009] Preferably, in step S1, rinse the crab shell several times with deionized water, then soak it in acetone for ultrasonic cleaning. After ultrasonic treatment, place the crab shell in an oven and dry it overnight. After drying, place it in a muffle furnace and calcine it at a temperature of 350 - 500 °C for 2 - 4 h, and grind it thoroughly into powder.

[0010] Preferably, in step S2, take the ground crab shell powder and soak it in a mixed solution containing phenolic resin, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, and ethanol, and evaporate it at room temperature for 6 h - 12 h; place the material after evaporation at room temperature in an oven and thermally cure it at 100 - 150 °C for 12 - 24 h.

[0011] Preferably, in step S3, place the thermally cured material in a tubular furnace under an N2 atmosphere and calcine it at 350 - 900 °C for 2 - 4 h; wash the calcined material with concentrated HCl to remove CaCO3, then wash it with deionized water and ethanol, and then place it in an oven and dry it at 100 °C for 24 h to obtain the biomass carbon material.

[0012] Preferably, in step S4, acidify the biomass carbon material with concentrated HNO3 and react at 90 °C for 1 h; then impregnate the acidified biomass carbon material in a cobalt salt solution in a certain proportion, and the solvent is any one of water, n-propanol, and ethanol. Ultrasonically disperse it, then dry it overnight at 80 °C, and calcine the mixture in a tubular furnace under an N2 atmosphere at 500 - 800 °C for 2 - 4 h to obtain the cobalt-based catalyst supported on biomass carbon.

[0013] Preferably, the cobalt salt is any one of chloride salts, nitrate salts, sulfate salts, and carbonate salts; the solvent is any one of water, n-propanol, and ethanol, and the molar ratio of the cobalt salt to the biomass carbon is 1:15 - 1:30.

[0014] The cobalt-based catalyst supported on biomass carbon prepared by a method for preparing a cobalt-based catalyst supported on biomass carbon is used for removing organic wastewater.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: Carbon materials have a high specific surface area, good chemical stability and electrical conductivity, and can also activate PMS to degrade organic pollutants through a non-free radical pathway. Introducing a carbon carrier into the Co-based catalyst can effectively disperse the active centers through the interaction with the surface functional groups of the carrier, increase the active sites of the catalyst, and effectively inhibit the leaching of toxic cobalt ions. A mutual force will form between the Co compound and the carrier, enabling it to stably exist on the carrier material, which is conducive to reducing ion leaching and improving the stability of the catalyst. It is easy to recycle and can be reused, with high economic benefits. The catalyst uses less amount to degrade organic pollutants, the method is simple, without additional energy input, and can efficiently activate persulfate at room temperature and without light, generating a large number of active species to efficiently degrade organic pollutants, saving energy and protecting the environment. Description of the Drawings

[0016] Figure 1 XRD pattern of the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0017] Figure 2 TEM image of the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0018] Figure 3 Effect diagram of the biomass carbon-supported cobalt-based catalyst prepared at different calcination temperatures activating persulfate to degrade Rhodamine B by the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0019] Figure 4 Effect diagram of adding different dosages of the catalyst to activate persulfate to degrade Rhodamine B by the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0020] Figure 5 Effect diagram of adding different dosages of persulfate to degrade Rhodamine B by the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0021] Figure 6 Effect diagram of the catalyst activating persulfate to degrade Rhodamine B at different operating temperatures by the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention;

[0022] Figure 7 Effect diagram of activating persulfate to degrade different dye organic pollutants by the preparation method of the biomass carbon-supported cobalt-based catalyst according to the present invention. Detailed Embodiments

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Referring to Figure 1-7 , a preparation method of a biomass carbon-supported cobalt-based catalyst includes: S1. Pretreat the crab shell and grind it into powder;

[0025] S2. Immerse the crab shell powder in a mixed solution containing phenolic resin, triblock copolymer and ethanol, and then perform thermal curing treatment;

[0026] S3. Calcinate the thermally cured material at high temperature in an N2 atmosphere, and perform washing and drying after calcination to obtain a biomass carbon material;

[0027] S4. Immerse the biomass carbon material in an HNO3 solution for acidification treatment, impregnate the acidified biomass carbon material in a cobalt salt solution after acidification, and then perform drying and calcination, and fully grind to obtain CoO x @BC catalyst.

[0028] The biomass carbon-supported cobalt-based catalyst is used for removing organic wastewater. When applied, it includes the following steps: Add 500 mL of organic pollutants with a concentration of 50 mg / L into a reaction vessel. Under magnetic stirring, add 0.005 - 0.03 g / L of CoOx@BC catalyst. After adsorption for 30 min to reach the adsorption-desorption equilibrium, add 0.02 - 0.06 g / L of PMS to start the reaction. Start timing after adding PMS, take a sample every 1 min, and add the filtrate into a centrifuge tube containing 1 mL of methanol until the organic pollutants are completely degraded.

[0029] During application, use magnetic stirring to uniformly disperse CoO x @BC and PMS in the organic pollutant solution in sequence for catalytic degradation. The principle is that CoO x @BC activates PMS, and O2, SO4 ·– , ·OH active species are generated in the system. The free radical and non-free radical pathways are combined to efficiently degrade organic pollutants.

[0030] Example 1

[0031] (1) The crab shells were rinsed several times with deionized water and then soaked in acetone for ultrasonic cleaning for 30 min. The ultrasonicated crab shells were placed in an oven and dried overnight. After drying, they were placed in a muffle furnace and calcined at 350 °C for 4 h, and then ground into powder. Subsequently, the ground crab shell powder was soaked in a mixed solution containing 1 g of phenolic resin, 0.5 g of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer and 16 g of ethanol, and evaporated at room temperature for 6 h; the material after evaporation at room temperature was placed in an oven and thermally cured at 100 °C for 24 h. Subsequently, the thermally cured material was placed in a tubular furnace under N2 atmosphere and calcined at 350 °C for 2 h, and then heated to 900 °C and calcined for 4 h. The calcined material was washed with 6 M HCl to remove CaCO3, then washed with deionized water and ethanol, and then placed in an oven and dried at 100 °C for 24 h to obtain a biomass carbon material;

[0032] (2) 1.15 g of the biomass carbon material was acidified with concentrated HNO3 at 90 °C for 1 h. The acidified biomass carbon material was impregnated in a mixed solution containing 1.052 g of Co(NO3)2·6H2O and 10 mL of n-propanol, ultrasonicated for 2 h, and then dried at 80 °C overnight. The mixture was placed in a tubular furnace under N2 atmosphere and calcined at 600 °C for 4 h at a heating rate of 5 °C / min to obtain a CoOx@BC catalyst.

[0033] (3) At room temperature (25 °C), 500 mL of a 50 mg / L rhodamine B solution was prepared in a wide-mouth bottle, 10 mg of the above material was added, and stirred thoroughly for 30 min to reach the adsorption and desorption equilibrium.

[0034] (4) 20 mg of persulfate was added to the reaction system. Samples were taken at intervals, quenched with methanol, and the concentration of the residual organic matter solution was measured using a UV-visible spectrophotometer.

[0035] Example 2

[0036] In the material synthesis, the types of solvents were changed to deionized water and methanol respectively, and the rest remained unchanged. Steps 1, 3 and 4 in Example 1 were repeated.

[0037] Example 3:

[0038] In the material synthesis, the final calcination temperatures of the materials were changed to 500 °C, 700 °C and 800 °C respectively, and the rest remained unchanged. Steps 1, 3 and 4 in Example 1 were repeated. The experimental results are shown in Figure 3 .

[0039] Example 4:

[0040] The catalyst dosages were changed to 2.5 mg, 5 mg and 15 mg respectively, and the rest remained unchanged. Steps 1, 2 and 4 in Example 1 were repeated. The experimental results are shown in Figure 4 .

[0041] Example 5:

[0042] The dosages of persulfate were changed to 10 mg, 15 mg, and 30 mg respectively, and the rest remained unchanged. Steps 1, 2, and 3 in the examples were repeated. The experimental results are shown in Figure 5 .

[0043] Example 6:

[0044] The initial temperatures of the reaction were changed to 20 °C and 30 °C, and the rest remained unchanged. Steps 1, 2, and 4 in the examples were repeated. The experimental results are shown in Figure 6 .

[0045] Example 7:

[0046] The types of target pollutants were changed to methylene blue (MB) and methyl orange (MO), and the rest remained unchanged. Steps 1, 2, and 4 in the examples were repeated. The experimental results are shown in Figure 7 .

[0047] The number of devices and the treatment scale described here are used to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be apparent to those skilled in the art. Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the illustrated and described examples here.

Claims

1. A preparation method of a cobalt-based catalyst supported on biomass carbon, characterized in that, It includes the following steps: S1. Pretreat the crab shells by grinding them into powder. In step S1, rinse the crab shells several times with deionized water, then soak them in acetone for ultrasonic cleaning. After ultrasonic treatment, place the crab shells in an oven and dry them overnight. After drying, place them in a muffle furnace and calcine them at a temperature of 350 - 500 °C for 2 - 4 h, and then grind them into powder thoroughly; S2. Immerse the crab shell powder in a mixed solution containing phenolic resin, triblock copolymer and ethanol, and then carry out heat curing treatment; S3. Calcinate the heat-cured material at high temperature under N2 atmosphere, and after calcination, wash and dry it to obtain the biomass carbon material. Place the heat-cured material in a tubular furnace under N2 atmosphere, calcine it at 350 °C for 2 h, and then raise the temperature to 900 °C and calcine it for 4 h. Wash the calcined material with concentrated HCl to remove CaCO3, then wash it with deionized water and ethanol, and then place it in an oven and dry it at 100 °C for 24 h to obtain the biomass carbon material; S4. Immerse the biomass carbon material in an HNO3 solution for acidification treatment. After acidification, impregnate the biomass carbon material in a cobalt salt solution and then dry and calcine it. Grind it thoroughly to obtain CoO. x @BC catalyst; Acidify the biomass carbon material with concentrated HNO3 and react at 90 °C for 1 h. Subsequently, impregnate the acidified biomass carbon material in a cobalt salt solution in a certain proportion. The solvent is any one of water, n-propanol, and ethanol. Ultrasonically disperse it, then dry it at 80 °C overnight, and calcine the mixture in a tubular furnace at 600-800 °C in an N2 atmosphere for 2-4 h to obtain the cobalt-based catalyst supported on biomass carbon.

2. The preparation method of a biomass carbon-supported cobalt-based catalyst according to claim 1, characterized in that, In step S2, take the ground crab shell powder and soak it in a mixed solution containing phenolic resin, polyethylene oxide - polypropylene oxide - polyethylene oxide triblock copolymer and ethanol, and evaporate it at room temperature for 6 - 12 h. Place the material after evaporation at room temperature in an oven and heat cure it at 100 - 150 °C for 12 - 24 h.

3. The preparation method of a cobalt-based catalyst supported on biomass carbon according to claim 2, wherein, The cobalt salt is any one of chloride salts, nitrate salts, sulfate salts, and carbonate salts; the solvent is any one of water, n-propanol and ethanol, and the molar ratio of the cobalt salt to the biomass carbon is 1:15 - 1:

30.

4. The cobalt-based catalyst supported on biomass carbon prepared by the method according to claim 1 is applied to the removal of organic wastewater.

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