Biochar material for repairing cadmium and tetracycline combined pollution in water body as well as preparation method and application of biochar material

Abstract

The invention relates to a biochar material for repairing cadmium and tetracycline combined pollution in a water body as well as preparation and application of the biochar material, and belongs to the technical field of water body pollution repairing. Comprising the following steps: (1) cleaning, drying and grinding plant tissues of solanum nigrum plants after the cadmium-polluted soil is repaired by fungi and solanum nigrum, so as to obtain solanum nigrum plant tissue powder; and (2) pyrolyzing the black nightshade plant tissue powder at 400-600 DEG C for 1-3 hours, cooling to 20-30 DEG C, and grinding to obtain the biochar material for repairing cadmium and tetracycline combined pollution in the water body. According to the invention, the plant tissue of the nightshade plant after the cadmium-polluted soil is repaired by the combination of fungi and nightshade is used as the raw material of the biochar material for the first time, so that the resource utilization of the polluted soil repairing plant is realized. The problem of plant treatment after polluted soil remediation is solved, consumption of extra resources is avoided, and the sewage treatment cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies, its preparation and application, belonging to the technical field of water pollution remediation. Background Art

[0002] Antibiotics are often used as growth promoters in animal husbandry, but most of them cannot be adsorbed and are eventually excreted into the environment. Heavy metals are released into the ecosystem through the use of fertilizers, sewage sludge and pesticides containing heavy metals, making the coexistence of tetracycline (TC) and cadmium (Cd) a common pollution phenomenon in natural water bodies.

[0003] Current research on biochar in the field of pollutant adsorption is mostly limited to single organic pollutants or heavy metals. Chinese patent document CN117046444A discloses a method for repairing arsenic and cadmium combined pollution with layered multi-metal oxide-based magnetic biochar. By mixing biomass raw materials with iron salt solution and pre-magnetic pyrolysis, layered multi-metal oxide-based magnetic biochar is prepared by hydrothermal method, thus significantly reducing the mobility and bioavailability of arsenic and cadmium. However, this patent only targets heavy metal-polluted water bodies. The physical and chemical properties of organic matter and heavy metals are quite different, and their repair mechanisms are different, so it cannot be directly applied to water bodies polluted by heavy metals and organic compounds. Therefore, there is an urgent need to develop a repair technology suitable for the combined pollution of heavy metals and antibiotics. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies, its preparation and application.

[0005] The technical solution of the present invention is as follows:

[0006] A preparation method of a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies, comprising the following steps:

[0007] (1) Take the plant tissue of Solanum nigrum plants after the combined remediation of cadmium-polluted soil by fungi and Solanum nigrum. After washing, drying and grinding, Solanum nigrum plant tissue powder is obtained;

[0008] (2) Pyrolyze the Solanum nigrum plant tissue powder at 400-600 °C for 1-3 h, cool it to 20-30 °C, and after grinding, obtain a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies.

[0009] Preferably according to the present invention, in step (1), the Solanum nigrum plants after the combined remediation of cadmium-polluted soil by fungi and Solanum nigrum refer to Solanum nigrum plants after the combined remediation of cadmium-polluted soil by Aspergillus tubingensis, Mucor circinelloides and Penicillium oxalicum for 3 months. During the remediation process, the three fungi invade the plant roots by producing a large number of hyphae and interact with the plants to form mycorrhizae.

[0010] Preferably according to the present invention, in step (1), the plant tissue is Solanum nigrum stem, Solanum nigrum leaf or Solanum nigrum mycorrhiza.

[0011] More preferably, the plant tissue is Solanum nigrum mycorrhiza.

[0012] Preferably according to the present invention, in step (2), the Solanum nigrum plant tissue powder is pyrolyzed at 450 - 550 °C for 1.5 - 2.5 h.

[0013] More preferably, the Solanum nigrum plant tissue powder is pyrolyzed at 550 °C for 2 h.

[0014] A biochar material for the remediation of cadmium and tetracycline co - polluted water bodies is prepared by the above - mentioned method.

[0015] The application of the above biochar material in the remediation of cadmium and tetracycline co - polluted water bodies.

[0016] Preferably according to the present invention, the application method is as follows:

[0017] The biochar material is added to the cadmium and tetracycline co - polluted water body at a ratio of 0.8 - 1.6 g / L, mechanically stirred and oscillated for 20 - 30 h to make the biochar evenly dispersed in the co - polluted water body and fully react with the pollutants.

[0018] Those not detailed in the present invention can be carried out according to the existing technology.

[0019] The technical features and beneficial effects of the present invention:

[0020] 1. The present invention first uses the plant tissue of Solanum nigrum plants after the combined remediation of cadmium - polluted soil by fungi and Solanum nigrum as the raw material of the biochar material, realizing the resource utilization of the plants for contaminated soil remediation. It not only solves the problem of the disposal of plants after contaminated soil remediation but also avoids the consumption of additional resources, greatly reducing the cost of sewage treatment.

[0021] 2. The biochar material provided by the present invention, especially the Solanum nigrum - based mycorrhizal biochar material, shows good adsorption performance in cadmium and tetracycline co - polluted water bodies, has strong anti - interference ability and co - adsorption ability for composite pollutants. In the laboratory adsorption test, the adsorption capacity for Cd reached 1.55 mg / g, and the adsorption capacity for TC reached 20.41 mg / g. In the actual water sample adsorption test, the adsorption capacity for Cd reached 1.49 mg / g, and the adsorption capacity for TC reached 17.28 mg / g.

[0022] 3. The application method of the present invention is relatively simple. It only needs to add biochar to the water body contaminated by cadmium and tetracycline in a certain proportion, carry out an oscillation reaction, and finally separate the biochar and the treated water body by centrifugation and filtration. In addition, as the raw material, Solanum nigrum is widely sourced and inexpensive, further reducing the preparation cost of biochar, making this remediation method have good economic efficiency and practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the adsorption capacity of the biochar material for pollutants in Example 1 of the present invention.

[0024] Figure 2 It is the scanning electron microscope image and energy spectrum analysis diagram (EDX) of the biochar material before and after adsorption in Example 1 of the present invention;

[0025] In the figure, (a) is the scanning electron microscope image of the biochar material before adsorption in Example 1; (b) is the scanning electron microscope image of the biochar material after adsorption in Example 1; (1) is the energy spectrum analysis diagram of the biochar material before adsorption in Example 1; (2) is the energy spectrum analysis diagram of the biochar material after adsorption in Example 1.

[0026] Figure 3 It is the remediation effect of the biochar material on actual sewage in Example 1 of the present invention;

[0027] In the figure, (a) is the result of Cd adsorption capacity; (b) is the result of TC adsorption capacity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following further illustrates the solution of the present invention through specific examples and drawings, but it does not limit the scope of protection required by the present invention. The raw material components used in the examples are all conventional raw materials, and the equipment used is all conventional equipment, which can be purchased from the market.

[0029] The Solanum nigrum plants after the combined remediation of cadmium-contaminated soil using fungi and Solanum nigrum in the examples come from the plant greenhouse cultivation of the School of Municipal and Environmental Engineering, Shandong Jianzhu University. The plants are Solanum nigrum plants after 3 months of combined remediation of cadmium-contaminated soil by Aspergillus tubingensis, Mucor circinelloides, Penicillium oxalicum and Solanum nigrum. During the remediation process, the three fungi produce a large number of hyphae, invade the plant roots, and interact with the plants to form mycorrhizae.

[0030] Example 1

[0031] A preparation method of a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies, comprising the following steps:

[0032] (1) Select the Solanum nigrum plants after the combined remediation of cadmium - contaminated soil by fungi and Solanum nigrum, collect the mycorrhizal parts of the Solanum nigrum plants to ensure the integrity of the samples; after collection, carefully wash the mycorrhizae of Solanum nigrum with water, air - dry naturally, and then put them into an electro - thermal blast drying oven at 110 °C for drying to constant weight;

[0033] Then use a high - speed universal grinder to grind the dried mycorrhizae of Solanum nigrum to obtain mycorrhizal powder of Solanum nigrum; this mycorrhizal powder of Solanum nigrum has a large specific surface area, which is beneficial to the heat transfer and reaction during the subsequent pyrolysis process. Moreover, the powdered raw material can also make the properties of the prepared biochar more uniform, improving its adsorption performance for Cd and tetracycline;

[0034] (2) Place the mycorrhizal powder of Solanum nigrum in a 20 - mL quartz crucible, cover the lid and wrap it tightly with tin foil, and put it into a box - type resistance furnace for pyrolysis treatment; set the pyrolysis temperature at 550 °C and the pyrolysis time at 2 h; under these temperature and time conditions, the organic substances in the mycorrhizae of Solanum nigrum will gradually be converted into biochar; after pyrolysis, turn off the power of the resistance furnace, wait for the temperature in the furnace to naturally drop to room temperature (25 °C), then take out the crucible and take out the carbonized mycorrhizae of Solanum nigrum; use a mortar to grind the carbonized mycorrhizae of Solanum nigrum again to obtain a mycorrhizal biochar material of Solanum nigrum (RCF); re - grinding can make the biochar particles more delicate and uniform, further improving its specific surface area and adsorption performance.

[0035] Example 2

[0036] A preparation method of a biochar material for the remediation of cadmium and tetracycline compound pollution in water bodies, the specific steps are the same as those in Example 1, except that the plant tissue used in this example is the stem of Solanum nigrum, and the pyrolysis temperature in step (2) is set at 500 °C, and the product obtained is a stem biochar material of Solanum nigrum (SCF).

[0037] Example 3

[0038] A preparation method of a biochar material for the remediation of cadmium and tetracycline compound pollution in water bodies, the specific steps are the same as those in Example 1, except that the plant tissue used in this example is the leaf of Solanum nigrum, the pyrolysis temperature in step (2) is set at 450 °C, and the pyrolysis time is shortened to 1 h, and the product obtained is a leaf biochar material of Solanum nigrum (LCF).

[0039] Comparative example

[0040] A preparation method of a Solanum nigrum root biochar, the specific preparation method is the same as that in Example 1, except that in step (1), only the mycorrhizal parts of the Solanum nigrum plants after the remediation of cadmium - contaminated soil by Solanum nigrum are selected to prepare biochar, and the Solanum nigrum root biochar (CF) after single - Solanum - treatment is obtained.

[0041] Test example 1

[0042] Through the simulated TC-Cd composite adsorption experiment of the composite polluted water body, the adsorption amounts of TC and Cd by the Solanum nigrum mycorrhizal biochar material (RCF), Solanum nigrum stem biochar material (SCF), Solanum nigrum leaf biochar material (LCF) prepared in Examples 1 to 3, and the Solanum nigrum root biochar (CF) after single Solanum nigrum treatment were measured. The method is as follows:

[0043] 1. Prepare a Cd solution with a concentration of 300 mg / L and a TC solution with a concentration of 1000 mg / L. Then transfer 5 mL of the Cd solution and 15 mL of the TC solution into a 500 mL volumetric flask, and add deionized water for dilution to obtain a simulated composite polluted water body (500 mL) with a Cd concentration of 3 mg / L and a TC concentration of 30 mg / L.

[0044] Take 0, 0.5, 1, 2, 3, 4 mL of the TC stock solution, and make the volume up to 100 mL respectively to obtain TC solutions with gradient concentrations of 0, 5, 10, 20, 30, 40 mg / L. Measure the absorbance of the samples of the gradient concentration TC solutions at 356 nm, and draw a standard curve based on the absorbance values.

[0045] 2. Add 0.02 g of Solanum nigrum mycorrhizal biochar material (RCF), 0.02 g of Solanum nigrum stem biochar material (SCF), 0.02 g of Solanum nigrum leaf biochar material (LCF), and 0.02 g of Solanum nigrum root biochar (CF) after single Solanum nigrum treatment into centrifuge tubes containing 20 mL of the simulated composite polluted water body, a total of 4 groups. Then place the centrifuge tubes in a shaker and oscillate at 25 °C and 160 r / min for 24 h to allow the biochar to fully contact the pollutants in the water body and undergo an adsorption reaction; after the reaction, centrifuge at a speed of 4000 r / min for 30 min, filter the supernatant with a filter membrane with a pore size of 0.45 μm, measure the Cd ion concentration in the filtrate by atomic absorption spectrophotometry, calculate the adsorption amount of Cd according to the detected concentration; measure the absorbance of the filtrate at 356 nm with a UV-visible spectrophotometer, calculate the corresponding TC concentration based on the standard curve, and calculate the adsorption amount of TC. The results are shown in Table 1, and the adsorption amount results of the Solanum nigrum mycorrhizal biochar material (RCF) for the pollutants are as Figure 1 shown.

[0046] Table 1. Adsorption of Cd-TC composite pollutants by the biochars in Examples 1 to 3

[0047]

[0048] From Table 1 and Figure 1It can be seen that compared with the Solanum nigrum root biochar (CF) treated with single Solanum nigrum, the Solanum nigrum mycorrhizal biochar material (RCF), Solanum nigrum stem biochar material (SCF) and Solanum nigrum leaf biochar material (LCF) have significantly better adsorption effects on Cd and TC, realizing the resource utilization of plants for polluted soil remediation. It not only solves the problem of the disposal of plants after polluted soil remediation, but also avoids the consumption of additional resources, greatly reducing the cost of sewage treatment.

[0049] Among them, in the simulated composite polluted water body with a Cd concentration of 3 mg / L and a TC concentration of 30 mg / L, the adsorption capacity of the Solanum nigrum mycorrhizal biochar material (RCF) for Cd reached 1.55 mg / g, and the adsorption capacity for TC reached 20.41 mg / g, which was significantly better than the adsorption effects of the Solanum nigrum stem biochar material (SCF) and Solanum nigrum leaf biochar material (LCF) on Cd, which were 1.28 mg / L and 1.41 mg / L, and the adsorption effects on TC, which were 18.01 mg / g and 17.77 mg / g. This is because during the mycorrhizal formation process, the three fungi invaded the plant roots by producing a large number of hyphae and shuttled through the plant root tissues. After pyrolysis into biochar materials, a large number of pores were formed at the original hypha positions, making the mycorrhizal biochar material have a larger porosity and thus better adsorption effect.

[0050] 3. Scanning electron microscopy observation and energy spectrum analysis were carried out on the Solanum nigrum mycorrhizal biochar material (RCF) before and after adsorption, and the results are as Figure 2 shown.

[0051] It can be Figure 2 seen that before adsorption, the surface of the Solanum nigrum mycorrhizal biochar material (RCF) presented a honeycomb-like porous structure with a pore size distribution of 1 - 5 μm. The inner wall of the pores was rough and rich in oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH). The main elements were C (75.3%), O (18.2%), K (3.1%), and Ca (2.4%), and there were no Cd and Cl signals. After adsorbing TC-Cd, Cd particles and TC flocs coexisted in the pores of the Solanum nigrum mycorrhizal biochar material (RCF), forming a multi-layer adsorption structure. Cracks with a depth of 5 - 10 μm appeared on the surface, which might be due to the complexation of cadmium ions with functional groups leading to structural expansion. The contents of Cd (6.2%) and Cl (2.3%) increased significantly, indicating that TC molecules (containing Cl and N) were successfully adsorbed by the Solanum nigrum mycorrhizal biochar material (RCF).

[0052] Experimental Example 2

[0053] For the TC-Cd composite adsorption experiment in actual sewage, the adsorption capacities of the Solanum nigrum mycorrhizal biochar material (RCF) prepared in Example 1 for TC and Cd were measured as follows:

[0054] 1. Prepare a Cd solution with a concentration of 300 mg / L and a TC solution with a concentration of 1000 mg / L.

[0055] Add 0.1 mL of the Cd solution and the TC solution to a centrifuge tube, and then make up the volume to 20 mL with lake water, reclaimed water, river water, and tap water respectively to obtain 4 kinds of composite polluted water bodies (20 mL).

[0056] 2. Add 0.02 g of Solanum nigrum mycorrhizal biochar material (RCF) to the centrifuge tube containing 20 mL of the composite polluted water body, then place the centrifuge tube in a shaker, and oscillate at 25 °C and 160 r / min for 24 h to allow the biochar to fully contact the pollutants in the water body and undergo an adsorption reaction; after the reaction, centrifuge at a speed of 4000 r / min for 30 min, filter the supernatant with a filter membrane with a pore size of 0.45 μm, measure the Cd ion concentration in the filtrate by atomic absorption spectrophotometry, calculate the adsorption amount of Cd according to the detected concentration; measure the absorbance of the filtrate at 356 nm with a UV-visible spectrophotometer, calculate the corresponding TC concentration based on the standard curve, and calculate the adsorption amount of TC. The results are as Figure 3 shown.

[0057] As Figure 3 can be seen, among the 4 different water bodies polluted by cadmium and tetracycline, the adsorption effect of the Solanum nigrum mycorrhizal biochar material on Cd is the best in lake water, with an adsorption amount reaching 1.49 mg / g, and the worst adsorption effect is in the reclaimed water sample, with an adsorption amount of only 1.30 mg / g. At the same time, the adsorption effect of the Solanum nigrum mycorrhizal biochar material on TC is the best in lake water, and the adsorption effect of the sewage simulated by tap water is the second, with adsorption amounts of 17.28 mg / g and 16.99 mg / g respectively. It shows that the Solanum nigrum mycorrhizal biochar material (RCF) also exhibits good adsorption performance in the actual water body polluted by cadmium and tetracycline, with strong anti-interference ability and co-adsorption ability for composite pollutants.

[0058] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A preparation method of a biochar material for the remediation of cadmium and tetracycline combined pollution in water bodies, characterized in that, It includes the following steps: (1) Take the plant tissues of Solanum nigrum plants after the combined remediation of cadmium - contaminated soil by fungi and Solanum nigrum. After washing, drying and grinding, obtain Solanum nigrum plant tissue powder; (2) Pyrolyze the Solanum nigrum plant tissue powder at 400 - 600 °C for 1 - 3 h, cool down to 20 - 30 °C, and after grinding, obtain a biochar material for the remediation of cadmium and tetracycline co - contaminated water bodies.

2. The preparation method according to claim 1, characterized in that, In step (1), the Solanum nigrum plants after the combined remediation of cadmium - contaminated soil by fungi and Solanum nigrum refer to: Solanum nigrum plants after 3 months of combined remediation of cadmium - contaminated soil by Aspergillus tubingensis, Mucor circinelloides, Penicillium oxalicum and Solanum nigrum.

3. The preparation method according to claim 1, characterized in that, In step (1), the plant tissues are Solanum nigrum stems, Solanum nigrum leaves or Solanum nigrum mycorrhizae.

4. The preparation method according to claim 3, characterized in that, The plant tissue is Solanum nigrum mycorrhizae.

5. The preparation method according to claim 1, characterized in that, In step (2), the Solanum nigrum plant tissue powder is pyrolyzed at 450 - 550 °C for 1.5 - 2.5 h.

6. The preparation method according to claim 5, characterized in that, The Solanum nigrum plant tissue powder is pyrolyzed at 550 °C for 2 h.

7. A biochar material for the remediation of combined cadmium and tetracycline pollution in water bodies, characterized in that, Prepared according to any one of claims 1 - 6.

8. Use of the biochar material according to claim 7 in the remediation of cadmium and tetracycline co - contaminated water bodies.

9. The application according to claim 8, characterized in that The application method is as follows: Add the biochar material to the cadmium and tetracycline co - contaminated water body at a ratio of 0.8 - 1.6 g / L, mechanically stir and oscillate for 20 - 30 h to make the biochar evenly dispersed in the co - contaminated water body and fully react with the pollutants.

Images