Biomass carbon material copper-loaded adsorbent with high specific surface area as well as preparation method and application of biomass carbon material copper-loaded adsorbent

Abstract

The invention discloses a biomass carbon material copper-loaded adsorbent with a high specific surface area as well as a preparation method and application of the biomass carbon material copper-loaded adsorbent. The biomass carbon-loaded copper adsorbent comprises a biomass carbon carrier and an active component CuCl loaded on the carrier, and the preparation method of the biomass carbon carrier comprises the following steps: (1) putting dry tea waste residues into a tubular furnace, and performing carbonization treatment in an inert atmosphere to obtain a precursor; (2) uniformly mixing the precursor with an activating agent, putting the mixture into a tubular furnace, calcining at the constant temperature of 700-800 DEG C in an inert atmosphere for activating treatment, and naturally cooling to room temperature after calcining to obtain a carbon sample; the activating agent is potassium hydroxide or sodium hydroxide; and (3) washing, filtering and drying the carbon sample to obtain the biomass carbon carrier. The invention discloses application of the biomass carbon-loaded copper adsorbent as a CO adsorbent, and solves the problems that metal particles in the existing copper-loaded adsorbent are easy to agglomerate, the effective utilization rate is low and the adsorption capacity is low.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass resource utilization, and specifically relates to a high specific surface area biocarbon-supported copper adsorbent and a preparation method and application thereof. Background Art

[0002] Since the Industrial Revolution, greenhouse gas emissions have continued to increase, leading to large-scale natural disasters such as land desertification, glacier melting and sea level rise. Among them, carbon dioxide accounts for more than 80% of total greenhouse gas emissions [Park JH, et al. Chemical Engineering Journal, 2022, 427: 130980.]. Therefore, in order to reduce the harm caused by the greenhouse effect, carbon capture, utilization and storage technology (CCUS) and the reduction of carbon dioxide emissions have been widely discussed and implemented [Kaur B, et al. Microporous and Mesoporous Materials, 2019, 282: 146-158.]. In addition to the carbon dioxide emitted when fossil fuels are used, the conventional incineration of biomass and other wastes will produce carbon-containing gases (such as CO2), dust and other gases (NO2, SO2), causing serious environmental pollution [Xu P, et al. Heliyon, 2023, 9 (5): e16311.]. In addition, landfilling of biomass and other wastes not only requires a long degradation time, but also easily causes pollution of land resources or groundwater [Yaashikaa PR, et al. Chemosphere, 2022, 309: 136627.]. On the other hand, most of these wastes are composed of carbon elements, and their recycling is also of great significance to the goals of carbon peak and carbon neutrality. Compared with the treatment methods of incineration and landfilling, converting organic waste into various carbon materials through simple methods is a cleaner and more valuable approach [Chen S, et al. Science of the Total Environment, 2020, 710: 136250.]. Unlike the preparation methods of carbon materials such as graphene, carbon nanotubes, and carbon nanofibers, activated carbon (AC) can be prepared by using biomass, coal, petroleum coke and other carbon-containing raw materials as precursors through a carbonization process, so this is one of the effective methods for recycling carbon resources from waste biomass (e.g., tea waste residues). Activated carbon (AC) is a conventional adsorbent, and its adsorption capacity mainly depends on the specific surface area and pore size distribution of the activated carbon [Seow YX, et al. Journal of Environmental Chemical Engineering, 2022, 10 (1): 107017.]. However, the carbon material obtained by carbonization has only low porosity and specific surface area, which limits its application. In addition, patent CN201410770801.6 discloses an adsorbent for recovering CO from tail gas, a preparation method and application thereof, which is prepared by loading active components and additives with activated carbon as a carrier, but its composition is complex and the CO adsorption capacity is low (the CO adsorption capacity is only 32.3 mL / g).Patent CN202311080061.9 uses the prepared MOF material as a precursor to coordinate the active component to obtain a highly dispersed adsorption center, but its preparation process is complicated and has low economic practicality. Therefore, the present invention reports a method for preparing a high specific surface area carbon-supported copper adsorption material based on waste biomass (tea waste residue) as a raw material and its application in the field of CO adsorption. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a biomass carbon-supported copper adsorbent with a high specific surface area and a preparation method and application thereof, which solves the problems of easy agglomeration of metal particles, low effective utilization rate and low adsorption capacity in the existing copper-supported adsorbents.

[0004] The technical solutions adopted to solve the above-mentioned technical problems are described below.

[0005] In a first aspect, the present invention provides a biomass carbon-supported copper adsorbent, the biomass carbon-supported copper adsorbent comprising a biomass carbon carrier and an active component CuCl supported on the carrier, and a method for preparing the biomass carbon carrier comprising the following steps:

[0006] (1) placing the dried tea waste residue in a tubular furnace under an inert atmosphere at 500-700° C. for carbonization treatment to obtain a precursor;

[0007] (2) mixing the precursor and the activator in a mass ratio of 1:3-5, placing the mixture in a tube furnace under an inert atmosphere at a constant temperature of 700-800° C. for activation treatment, and naturally cooling the temperature to room temperature after the calcination to obtain a carbon sample; the activator is potassium hydroxide or sodium hydroxide;

[0008] (3) Washing, filtering and drying the carbon sample to obtain a biomass carbon carrier.

[0009] Preferably, the specific surface area of ​​the biomass carbon carrier is 2500m 2 ·g -1 Up to 3000m 2 ·g -1 ; pore volume is 1.5cm 3 ·g -1 Up to 2.0cm 3 ·g -1 ; The pore diameter is 0.6nm to 2.5nm.

[0010] Preferably, in step (1), the carbonization treatment temperature is 600°C; the carbonization constant temperature time is 2h; and the heating rate is 5°C / min.

[0011] Preferably, in step (2), the activator is potassium hydroxide. Further preferably, the mass ratio of the precursor to potassium hydroxide is 1:4.

[0012] Preferably, in step (2), the precursor and the activator are mixed by grinding and mixing or by dissolving and soaking, and grinding and mixing is more preferred.

[0013] Preferably, in step (2), the activation treatment temperature is 800°C; the heating rate is 5°C / min; and the activation treatment time is 2h.

[0014] Preferably, in step (3), the washing step is to wash with deionized water, add 0.8-1.2 (preferably 1) mol / L HNO3 solution, stir for 0.5-1.5h (preferably 1h), filter, and then wash the carbon material with deionized water until the pH value of the filtrate is neutral.

[0015] Preferably, in step (3), the drying temperature is 80-110° C., more preferably 100° C.; the drying time is 10-15 h, more preferably 12 h.

[0016] Preferably, the mass ratio of the biomass carbon carrier to CuCl is 0.6-1.0:1.

[0017] In a second aspect, the present invention provides a method for preparing the biomass carbon-supported copper adsorbent according to the first aspect, comprising the following steps:

[0018] (1) placing the dried tea waste residue in a tubular furnace under an inert atmosphere at 500-700° C. for carbonization treatment to obtain a precursor;

[0019] (2) mixing the precursor and the activator in a mass ratio of 1:3-5, placing the mixture in a tube furnace under an inert atmosphere at a constant temperature of 700-800° C. for activation treatment, and naturally cooling the temperature to room temperature after the calcination to obtain a carbon sample; the activator is potassium hydroxide or sodium hydroxide;

[0020] (3) washing, filtering, and drying the carbon sample to obtain a biomass carbon carrier;

[0021] (4) The biomass carbon carrier and CuCl are mixed evenly and placed in a tube furnace. The mixture is heated to 300-400° C. and calcined for 3-5 h under an inert atmosphere to obtain a biomass carbon-supported copper adsorbent.

[0022] The technical details of the above steps (1)-(3) are the same as those of the first aspect and will not be repeated here.

[0023] Preferably, in step (4), the mass ratio of biomass carbon material to CuCl is 0.6:1-1.0:1.

[0024] Preferably, in step (4), the calcination temperature is 350°C; the calcination time is 4 hours; and the heating rate is 5°C / min.

[0025] In a third aspect, the present invention provides the use of the biomass carbon-supported copper adsorbent described in the first aspect as a CO adsorbent.

[0026] The biomass carbon-supported copper adsorbent contains Cu + The active components are evenly dispersed, the CO adsorption performance is excellent, and the adsorbent can be regenerated and recycled.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention uses tea waste as raw material and makes reasonable use of it, thereby reducing environmental pollution and production costs, and the preparation method is simple. The preparation method reported in the present invention can effectively convert tea waste into a high specific surface area (2500m 2 ·g -1 Up to 3000m 2 ·g -1 )Biomass carbon materials.

[0029] (2) Compared with the existing CO adsorbent preparation technology, the biomass carbon material prepared in the present invention as a carrier effectively improves the utilization rate of the active components, thereby enabling it to have a high CO adsorption capacity and good regeneration ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the XRD spectrum of the copper-loaded adsorbent prepared in Example 2. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0032] Embodiment 1:

[0033] Take the dried tea waste and place it in a tubular furnace, calcine it at a constant temperature of 600°C in a nitrogen atmosphere for two hours, with a heating rate of 5°C / min, and take it out after cooling to room temperature to obtain a precursor. Take 1.0g of the precursor and 4.0g of KOH solid (mass ratio is 1:4) and place them in a mortar for grinding and mixing for 5 minutes. Then place the sample in a tubular furnace and calcine it at a constant temperature of 800°C in a nitrogen atmosphere for two hours to obtain a carbon sample. The heating rate is 5°C / min. After washing the obtained sample once with deionized water, add 100mL of 1mol / LHNO3 solution, stir for 1h, and then filter. Then wash the carbon material 3 times with 100mL of deionized water until the pH value of the filtrate is neutral, and then place it in a 100°C oven to dry for 12h to obtain a high specific surface area biomass carbon material A (BET=2955.1m 2 ·g -1 , V t =1.63cm 3 ·g-1 , D DA =1.7nm, the texture properties of the biomass carbon material prepared in Example 1 were analyzed using a low-temperature N2 physical adsorption-desorption instrument (Micromeritics 3Flex). First, ~0.1g of the sample was pre-treated and degassed at 200°C for 6h to remove impurity gases and water on the sample surface. The treated sample was placed in liquid nitrogen for a low-temperature N2 physical adsorption-desorption experiment. The specific surface area of ​​the sample was calculated using the BET equation, and the pore size was calculated using the Dubinin-Astakhov equation).

[0034] Example 2

[0035] 2.6 g of the biomass carbon material A prepared in Example 1 and 2.6 g of CuCl powder were weighed in a beaker at a mass ratio of 1:1, and stirred quickly with a glass rod within two minutes to make them evenly mixed. Then, they were placed in a tube furnace and heated to 350°C under a 99.999% high-purity nitrogen atmosphere at a flow rate of 100 mL / min and a heating rate of 5°C / min. Then, they were calcined at this temperature for 4 hours to obtain a copper-loaded adsorbent named Cu-A. Figure 1 The XRD spectrum of the Cu-A adsorbent prepared in Example 2 shows a weaker diffraction peak of CuCl, indicating that Cu + The active components are highly dispersed on the surface of biomass carbon materials, and no other Cu-containing 0 Cu 2+ Crystalline phase of the species.

[0036] Example 3

[0037] A fixed bed reaction apparatus was used to carry out a CO adsorption performance evaluation test experiment on the Cu-A adsorbent prepared in Example 2. The sample was loaded into a stainless steel reaction tube in the order of gauze-quartz wool-adsorbent-quartz wool-gauze. The reaction tube was 25 cm long, 2 cm in inner diameter, and the adsorbent loading mass was 4-5 g. The adsorption temperature was room temperature, the pressure was 1 MPa, CO / (Ar+CO) in the raw gas was 20%, and the adsorption amount was calculated by the following formula.

[0038] CO dynamic adsorption amount = (adsorption breakthrough time × CO actual gas flow rate) / adsorbent mass

[0039] The results of the adsorption test show that under the conditions of room temperature, 1MPa, and CO / (Ar+CO)=20%, the CO adsorption capacity of the Cu-A adsorbent is 55.2mL / g. The above experimental results show that the CO adsorption capacity of the copper-supported adsorbent (Cu-A) prepared with high specific surface area biomass carbon material as the carrier is much higher than that of the adsorbent prepared by patent CN201410770801.6 (32.3mL / g).

[0040] Furthermore, the temperature was raised to 700°C under 99.999% high-purity nitrogen atmosphere at a gas flow rate of 100 mL / min and a heating rate of 5°C / min, and the adsorbed Cu-A adsorbent was desorbed under high temperature conditions for 1 hour, and the adsorption reaction of the desorbed Cu-A adsorbent was evaluated again. The above operation was repeated twice, and the adsorption amounts were 50.2 mL / g and 47.6 mL / g, respectively. This proves that after the temperature desorption treatment, the CO adsorption amount of the Cu-A adsorbent did not change significantly, and the adsorbent has good regeneration performance.

Claims

1. A biomass carbon-supported copper adsorbent, characterized in that: The biomass carbon-supported copper adsorbent comprises a biomass carbon carrier and an active component CuCl supported on the carrier. The preparation method of the biomass carbon carrier comprises the following steps: (1) placing the dried tea waste residue in a tubular furnace under an inert atmosphere at 500-700° C. for carbonization treatment to obtain a precursor; (2) mixing the precursor and the activator in a mass ratio of 1:3-5, placing the mixture in a tube furnace under an inert atmosphere at a constant temperature of 700-800° C. for activation treatment, and naturally cooling the temperature to room temperature after the calcination to obtain a carbon sample; the activator is potassium hydroxide or sodium hydroxide; (3) Washing, filtering and drying the carbon sample to obtain a biomass carbon carrier.

2. The biomass carbon-supported copper adsorbent according to claim 1, characterized in that: The specific surface area of ​​the biomass carbon carrier is 2500m 2 ·g -1 Up to 3000m 2 ·g -1 ; The pore volume is 1.5 cm 3 ·g -1 Up to 2.0cm 3 ·g -1 ; The pore diameter is 0.6nm to 2.5nm.

3. The biomass carbon-supported copper adsorbent according to claim 1, characterized in that: In step (1), the carbonization treatment temperature is 600°C; the carbonization constant temperature time is 2h; and the heating rate is 5°C / min.

4. The biomass carbon-supported copper adsorbent according to claim 1, characterized in that: In step (2), the activator is potassium hydroxide.

5. The biomass carbon-supported copper adsorbent according to claim 1, characterized in that: In step (2), the activation treatment temperature is 800°C; the heating rate is 5°C / min; and the activation treatment time is 2h.

6. The biomass carbon-supported copper adsorbent according to claim 1, characterized in that: The mass ratio of the biomass carbon carrier to CuCl is 0.6-1.0:

1.

7. A method for preparing a biomass carbon-supported copper adsorbent according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) placing the dried tea waste residue in a tubular furnace under an inert atmosphere at 500-700° C. for carbonization treatment to obtain a precursor; (2) mixing the precursor and the activator in a mass ratio of 1:3-5, placing the mixture in a tube furnace under an inert atmosphere at a constant temperature of 700-800° C. for activation treatment, and naturally cooling the temperature to room temperature after the calcination to obtain a carbon sample; the activator is potassium hydroxide or sodium hydroxide; (3) washing, filtering, and drying the carbon sample to obtain a biomass carbon carrier; (4) The biomass carbon carrier and CuCl are mixed evenly and placed in a tube furnace. The mixture is heated to 300-400° C. and calcined for 3-5 h under an inert atmosphere to obtain a biomass carbon-supported copper adsorbent.

8. The preparation method according to claim 7, characterized in that: In step (4), the mass ratio of biomass carbon material to CuCl is 0.6:1-1.0:

1.

9. The preparation method according to claim 7, characterized in that: In step (4), the calcination temperature is 350°C; the calcination time is 4 hours; and the heating rate is 5°C / min.

10. Use of the biomass carbon-supported copper adsorbent as claimed in claim 1 as a CO adsorbent.

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