Preparation method and application of a fish scale biochar antibacterial adsorption material

Abstract

The present invention belongs to the technical field of the preparation and application of nanomaterials, and particularly relates to a preparation method and application of a fish scale biochar antibacterial and adsorption material. The fish scales collected in the present invention are soaked in an alkali solution, washed, dried, and carbonized to obtain fish scale biochar. Then, the fish scale biochar is soaked in a silver nitrate solution in the dark and stirred, and then trisodium citrate dihydrate is added and stirred to undergo a reduction reaction to obtain fish scale biochar loaded with silver nanoparticles. Finally, it is calcined at a low temperature to obtain the fish scale biochar antibacterial and adsorption material. The fish scale biochar antibacterial and adsorption material prepared in the present invention has remarkable effects in antibacterial and heavy metal adsorption. The preparation method is simple, has good cycle stability, and a long validity period, and can be used for antibacterial, adsorption and separation treatment of heavy metal wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material preparation and application, and particularly relates to a preparation method and application of a fish scale biochar antibacterial adsorption material. Background Art

[0002] Biochar is a carbon-rich product produced by high-temperature slow pyrolysis of biomass raw materials. It has well-developed internal voids, large specific surface area, strong adsorption capacity, acid and alkali resistance, heat resistance, and easy regeneration. It is an environmentally friendly adsorbent. It has a strong adsorption capacity for soluble heavy metal ions and can effectively remove the color of wastewater. The structure and composition of biochar itself have a very important influence on the physicochemical properties and adsorption properties of the biochar prepared from it. At present, a variety of biomass wastes have been used as biochar precursors, including agricultural waste, forestry waste, aquaculture waste and sludge (Journal of Cleaner Production, 2022, 377: 134391). However, some biochars are still limited by the characteristics of the raw materials themselves, with small specific surface area and pore volume, resulting in poor adsorption performance.

[0003] my country is a major freshwater fish farming country, with annual output ranking first in the world. The freshwater fish farming industry is developing rapidly, and output is increasing year by year. According to statistics, my country's aquatic product farming output in 2021 was 53.9441 million tons, of which the largest category of various aquatic products was fish, 7.3718 million tons. At present, most fish scales are discarded, which not only causes environmental pollution, but also seriously wastes this available resource. Fish scales have a highly ordered three-dimensional structure, mainly composed of substances such as collagen and hydroxyapatite. The former can provide a carbon source, and the latter can serve as a natural template for the formation of porous carbon during the carbonization process (Journal of Cleaner Production, 2022, 42: 377-385). Therefore, fish scales as a fishery by-product are expected to become an ideal biochar precursor.

[0004] In the process of wastewater treatment, biochar often encounters the problem of bacterial growth, causing the water to become black and smelly. As a broad-spectrum antibacterial agent, nanosilver has a strong killing effect on a variety of Gram-positive bacteria, Gram-negative bacteria and fungi. It is stronger than antibiotics and is not easy to develop drug resistance and is widely used in various fields (Int J Biol Macromol, 2022, 206: 730-739). In addition, the unique microstructure and pore characteristics of biochar can be used as an excellent carrier of nanosilver particles. Therefore, the development of a biochar material with dual-effect functions of adsorption and antibacterial is of great significance for the treatment of heavy metal wastewater. Summary of the invention

[0005] In response to the above technical problems, the present invention provides a method for preparing and applying a fish scale biochar antibacterial adsorption material, using fish scales as biochar raw materials to prepare antibacterial materials loaded with nanosilver, thereby realizing the resource utilization of fish scale waste. The developed fish scale biochar antibacterial adsorption material can have high antibacterial efficiency and adsorption properties in heavy metal wastewater.

[0006] The present invention achieves the above object through the following technical solutions:

[0007] A method for preparing a fish scale biochar antibacterial adsorption material comprises the following steps:

[0008] (1) After pretreatment, fresh fish scales are placed in a tubular furnace for carbonization, taken out and naturally cooled to room temperature, and then ground and sieved to obtain fish scale biochar.

[0009] Furthermore, the fish scale pretreatment method is: rinse the fish scale with clean water to remove the mud and mucus on the surface of the fish scale, then soak the fish scale with sodium hydroxide solution and stir it for 24 hours to remove the protein, fat and fishy smell on the fish scale; then rinse with clean water until the solution is neutral, and then drain the water for later use. The mass concentration of the sodium hydroxide solution is 0.5-2%.

[0010] Further, the specific conditions of carbonization are: heating to 200-400°C at a heating rate of 8-12°C / min under an inert atmosphere for 1-3 hours, preferably, heating to 300°C for 2 hours.

[0011] (2) Immerse the fish scale biochar in a silver nitrate solution in the dark, stir for 1-2 hours, preferably 2 hours, then add trisodium citrate dihydrate, and continue stirring for 12-36 hours, preferably 24 hours, to allow Ag to + Reduced to nano-silver, fish scale biochar loaded with nano-silver was obtained.

[0012] Further, the concentration of the silver nitrate solution is 0.1-8.0 g / L; the mass volume ratio of fish scale biochar to silver nitrate solution is 1:4-40; and the amount of trisodium citrate dihydrate is 0.1-0.8 g. Preferably, the concentration of the silver nitrate solution is 0.5 g / L; the mass volume ratio of fish scale biochar to silver nitrate solution is 1:20; the amount of trisodium citrate dihydrate is 0.2 g; and the mass ratio of silver nitrate solution to sodium citrate dihydrate is 1:4.

[0013] (3) filtering and drying the fish scale biochar loaded with nanosilver obtained in step (2) and then placing it in a tube furnace for low-temperature calcination to remove the unreduced Ag. + The fish scale biochar is further heated to be reduced to nano-silver, and the nano-silver is better attached to the surface of the fish scale biochar. The biochar is then taken out and naturally cooled to room temperature. The fish scale biochar antibacterial adsorption material is obtained after grinding and sieving.

[0014] Further, the specific conditions of low-temperature calcination are: in an inert atmosphere, heating to 150-400°C at a heating rate of 8-12°C / min, and calcination time of 1-3 hours. Preferably, heating to 250°C, and calcination time of 2 hours.

[0015] The fish scale biochar antibacterial adsorption material prepared by the above method is used for inhibiting bacteria and / or adsorbing heavy metal ions in heavy metal wastewater.

[0016] The specific method of antibacterial application is as follows: Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa colonies were picked and placed in LB liquid culture medium (yeast powder 5g / L, sodium chloride 10g / L, beef peptone 10g / L), and cultured at 37°C. When the viable bacterial concentration of the culture medium reached 1.0×10 8 cfu / mL, 0.1 mL of the above colonies were respectively transferred and coated on LB solid medium (yeast powder 5 g / L, sodium chloride 10 g / L, beef peptone 10 g / L, agar 20 g / L). Then, a sterilized stainless steel puncher was used to punch a 9.0 mm diameter circular hole on the plate, and then 0.05-0.2 g of the above prepared fish scale biochar antibacterial adsorption material was poured into the hole, and finally placed in a 37 ° C incubator for 18 h, and the diameter of the antibacterial zone was measured with a ruler.

[0017] The test method of antibacterial rate is as follows: Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa colonies were selected and placed in LB liquid culture medium (yeast powder 5g / L, sodium chloride 10g / L, beef peptone 10g / L), and cultured at 37°C. When the viable bacterial concentration of the culture medium reached 1.0×10 8 cfu / mL, add 0.2-1.0g / L of the fish scale biochar antibacterial adsorption material prepared above, continue shaking culture for 1-9h, and obtain a bacterial suspension. Then take 0.05-0.2mL of the bacterial suspension and dilute it with 0.9% sterile saline for gradient dilution, count it by plate counting method, and calculate the antibacterial rate of the fish scale biochar antibacterial adsorption material in water.

[0018] The specific method for heavy metal ion adsorption is as follows: use ultrapure water to prepare lead nitrate mother liquor (1000 mg / L), mercury nitrate mother liquor (1000 mg / L), chromium nitrate mother liquor (600 mg / L), cadmium nitrate mother liquor (600 mg / L) and copper nitrate mother liquor (600 mg / L), and dilute the above mother liquors by 10 times in subsequent experiments, that is, Pb 2+ , Hg 2+ Cr 3+ 、Cd 2+ and Cu 2+The initial mass concentrations of the solutions were 100 mg / L, 100 mg / L, 60 mg / L, 60 mg / L and 60 mg / L, respectively. 20 mL of the above heavy metal ion solutions were measured and added to 50 mL centrifuge tubes, and 10 mg of fish scale biochar antibacterial adsorption material was added to the centrifuge tubes. After mixing evenly, the centrifuge tubes were placed in a constant temperature shaking table (25 ° C, 200 r / min) for 1-11 hours. After adsorption equilibrium, samples were taken and filtered to determine the residual Pb in the water samples. 2+ , Hg 2+ Cr 3+ 、Cd 2+ and Cu 2+ The mass concentration was calculated to obtain the corresponding adsorption rate.

[0019] The beneficial effects of the present invention are:

[0020] 1. The fish scale biochar antibacterial adsorption material prepared by the present invention has a large number of nano-silver particles, carbon pores and hydroxyapatite gathered on its surface, and has many types and sites of adsorbed heavy metals and a large adsorption capacity; moreover, a small amount of nano-silver can exert a good antibacterial effect, and can exert efficient antibacterial properties in heavy metal wastewater.

[0021] 2. The preparation method adopted by the present invention is simple and environmentally friendly, avoiding the problems of small specific surface area and pore volume of traditional biochar and agglomeration and leaching of nanosilver, and effectively increasing the antibacterial and adsorption properties of biochar.

[0022] 3. Fish scales are waste generated by the fish processing industry. Carbonizing them into biochar and loading them with nanosilver is an economical and efficient way to achieve resource utilization of waste. The preparation method of the fish scale biochar antibacterial adsorption material of the present invention is simple, with low production cost and energy consumption, and is easy to carry out industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The SEM images of the fish scale biochar (a) and the fish scale biochar antibacterial adsorption material (b) of Example 1;

[0024] Figure 2 This is the XPS graph of the fish scale biochar antibacterial adsorption material of Example 1;

[0025] Figure 3 Comparison of the reuse of the fish scale biochar antibacterial adsorption materials prepared in Example 1 (a), Comparative Example 1 (b), Comparative Example 2 (c) and Comparative Example 3 (d) in water bodies;

[0026] Figure 4 The fish scale biochar antibacterial adsorption material of Example 1 for Pb under different adsorption time conditions 2+ , Hg 2+ Cr 3+ 、Cd 2+ and Cu 2+ Comparison of adsorption rates;

[0027] Figure 5 Effect of low-temperature calcination temperature on the antibacterial effect of fish scale biochar antibacterial adsorption material: (A) Escherichia coli, (B) Staphylococcus aureus and (C) Pseudomonas aeruginosa. DETAILED DESCRIPTION

[0028] In order to further illustrate the preparation process and antibacterial effect of the present invention, the following examples are listed for illustration, but the present invention is not limited to the following examples.

[0029] Example 1

[0030] Rinse the mud and mucus on the surface of fresh fish scales with clean water, then soak the fish scales in 1% sodium hydroxide solution and stir for 24 hours, and then rinse with clean water until the clear solution is neutral as measured by pH test paper. After fully rinsing, pick up the fish scales and drain for 15-20 minutes. Place the pretreated fish scales in a tube furnace, heat to 300℃ at a heating rate of 10℃ / min in an inert atmosphere for carbonization for 2 hours, cool naturally to room temperature, grind and sieve to obtain fish scale biochar.

[0031] 5 g of fish scale biochar was immersed in 100 mL of silver nitrate solution (0.5 g / L) in the dark and stirred for 2 h. Then 0.2 g of trisodium citrate dihydrate was added and stirred for 24 h for reduction to obtain fish scale biochar loaded with nanosilver.

[0032] The fish scale biochar loaded with nanosilver was filtered and dried, then placed in a tubular furnace, heated to 250°C at a heating rate of 10°C / min under an inert atmosphere and calcined for 2h, naturally cooled to room temperature, and ground and sieved to obtain the fish scale biochar antibacterial adsorption material.

[0033] The SEM images of the fish scale biochar and the fish scale biochar antibacterial adsorption material prepared in this example are as follows: Figure 1 As shown, it can be seen that the fish scale biochar prepared in this embodiment presents a rough and porous structure, and a large number of nanosilver particles are gathered on the surface of the fish scale biochar antibacterial adsorption material.

[0034] The XPS image of the fish scale biochar antibacterial adsorption material prepared in this example is as follows: Figure 2 As shown, it can be seen that the proportion of silver element is much greater than that of silver ions, indicating that a large amount of silver element is loaded on the surface of fish scale biochar.

[0035] Example 2

[0036] Optimization of fish scale carbonization temperature and calcination temperature of fish scale biochar loaded with nanosilver:

[0037] According to the experimental steps of Example 1, the carbonization temperature of the fish scale and the calcination temperature of the fish scale biochar loaded with nanosilver were adjusted to prepare the fish scale biochar antibacterial adsorption material, and then the antibacterial experiment was carried out. The results are shown in Table 1. When the carbonization temperature of the fish scale was 300°C, the calcination temperature of the fish scale biochar loaded with nanosilver was changed to prepare the fish scale biochar antibacterial adsorption material. The effect of calcination temperature on the antibacterial effect is shown in Tables 2 and Figure 5 shown.

[0038] Table 1 Effect of carbonization temperature of fish scales and calcination temperature of fish scale biochar loaded with nanosilver on antibacterial effect

[0039]

[0040] Table 2 Effect of calcination temperature of fish scale biochar loaded with nanosilver on antibacterial effect

[0041]

[0042]

[0043] Example 3

[0044] Optimum concentration of silver nitrate solution:

[0045] According to the experimental steps of Example 1, the concentration of the silver nitrate solution was changed to 0.05 g / L, 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 4 g / L and 8 g / L, respectively, to prepare the fish scale biochar antibacterial adsorption material, and then the antibacterial test was carried out, and the results are shown in Table 3. The antibacterial test results show that when the silver nitrate concentration is less than 0.5 g / L, as the concentration of the silver nitrate solution increases, the antibacterial circle of the antibacterial adsorption material will become larger, but when the silver nitrate concentration is greater than 0.5 g / L, the antibacterial effect will gradually decrease and tend to equilibrium.

[0046] Table 3 Effect of silver nitrate solution concentration on antibacterial effect

[0047]

[0048] Example 4

[0049] The preferred dosage of trisodium citrate dihydrate is:

[0050] According to the experimental steps of Example 1, the dosage of trisodium citrate dihydrate was changed to 0.05g, 0.1g, 0.2g, 0.4g, 0.6g and 0.8g, respectively, to prepare fish scale biochar antibacterial adsorption material, and then the antibacterial test was carried out, and the results are shown in Table 4. The antibacterial test results show that when the dosage of trisodium citrate dihydrate is less than 0.2g, the antibacterial effect is enhanced with the increase of the dosage of trisodium citrate dihydrate, and there is no obvious difference in the antibacterial effect when the dosage exceeds 0.2g.

[0051] Table 4 Effect of trisodium citrate dihydrate dosage on antibacterial effect

[0052]

[0053] Example 5

[0054] Optimization of reduction reaction stirring time:

[0055] According to the experimental steps of Example 1, the stirring time of the reduction reaction was changed to 6 h, 12 h, 18 h, 24 h, 30 h and 36 h, respectively, to prepare the fish scale biochar antibacterial adsorption material, and then the antibacterial test was carried out, and the results are shown in Table 5. The results of the antibacterial test show that when the stirring time of the reduction reaction is less than 24 h, the antibacterial effect gradually increases with the increase of the stirring time; when the stirring time exceeds 24 h, there is no obvious difference in the antibacterial effect.

[0056] Table 5 Effect of reduction reaction stirring time on antibacterial effect

[0057]

[0058]

[0059] Example 6

[0060] Optimization of low temperature calcination time:

[0061] According to the experimental steps of Example 1, the low-temperature calcination time was changed to 0.5h, 1h, 1.5h, 2h, 2.5h and 3h, respectively, to prepare the fish scale biochar antibacterial adsorption material, and then the antibacterial test was carried out, and the results are shown in Table 6. The antibacterial test results show that the antibacterial effect is best when the low-temperature calcination time is 2h.

[0062] Table 6 Effect of low temperature calcination time on antibacterial effect

[0063]

[0064] Comparative Example 1

[0065] Rinse the mud and mucus on the surface of fresh fish scales with clean water, then soak the fish scales in 1% sodium hydroxide solution and stir for 24 hours, and then rinse with clean water until the clear solution is neutral as measured by pH test paper. After fully rinsing the fish scales, pick them up and drain for 15-20 minutes. Place the pretreated fish scales in a tube furnace and heat them to 300℃ at a heating rate of 10℃ / min in an inert atmosphere for carbonization for 2 hours, cool them naturally to room temperature, grind and sieve to obtain fish scale biochar.

[0066] 5 g of fish scale biochar was immersed in 100 mL of silver nitrate solution (0.5 g / L) in the dark and stirred for 2 h. Then 0.2 g of trisodium citrate dihydrate was added and stirred for 24 h for reduction to obtain fish scale biochar loaded with nanosilver.

[0067] The fish scale biochar loaded with nanosilver is filtered, dried, ground and sieved to obtain the fish scale biochar antibacterial adsorption material.

[0068] Comparative Example 2

[0069] Rinse the mud and mucus on the surface of fresh fish scales with clean water, then soak the fish scales in 1% sodium hydroxide solution and stir for 24 hours, and then rinse with clean water until the clear solution is neutral as measured by pH test paper. After fully rinsing the fish scales, pick them up and drain for 15-20 minutes. Place the pretreated fish scales in a tube furnace and heat them to 300℃ at a heating rate of 10℃ / min in an inert atmosphere for carbonization for 2 hours, cool them naturally to room temperature, grind and sieve to obtain fish scale biochar.

[0070] 5 g of fish scale biochar was soaked in 100 mL of silver nitrate solution (0.5 g / L) in the dark and stirred for 2 h. The soaked fish scale biochar was filtered, dried, and placed in a tube furnace, heated to 250 ° C at a heating rate of 10 ° C / min under an inert atmosphere and calcined for 2 h, cooled naturally to room temperature, and ground and sieved to obtain the fish scale biochar antibacterial adsorption material.

[0071] Comparative Example 3

[0072] Rinse the mud and mucus on the surface of fresh fish scales with clean water, then soak the fish scales in 1% sodium hydroxide solution and stir for 24 hours, and then rinse with clean water until the clear solution is neutral as measured by pH test paper. After fully rinsing the fish scales, pick them up and drain for 15-20 minutes. Place the pretreated fish scales in a tube furnace and heat them to 300℃ at a heating rate of 10℃ / min in an inert atmosphere for carbonization for 2 hours, cool them naturally to room temperature, grind and sieve to obtain fish scale biochar.

[0073] 5 g of fish scale biochar was immersed in 100 mL of silver nitrate solution (0.5 g / L) in the dark and stirred for 2 h. The fish scale biochar after being immersed in silver nitrate was filtered, dried, ground and sieved to obtain the fish scale biochar antibacterial adsorption material.

[0074] The antibacterial test was conducted on the fish scale biochar antibacterial adsorption materials of Example 1 and Comparative Examples 1-3, and the results are shown in Table 7. As can be seen from Table 7, the antibacterial effect of the fish scale biochar antibacterial adsorption material prepared by the method provided in Example 1 is significantly better than that of Comparative Examples 1-3.

[0075] Table 7 Comparison of the antibacterial zone size of fish scale biochar antibacterial adsorption materials prepared in Example 1 and Comparative Examples 1-3

[0076]

[0077] Application Examples

[0078] Antibacterial application test: Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa colonies were selected and placed in LB liquid culture medium (yeast powder 5g / L, sodium chloride 10g / L, beef peptone 10g / L), and cultured at 37°C. When the viable bacterial concentration of the culture medium reached 1.0×10 8 cfu / mL, 0.1 mL of the above colonies were respectively transferred and coated on LB solid medium (yeast powder 5 g / L, sodium chloride 10 g / L, beef peptone 10 g / L, agar 20 g / L). Then a sterilized stainless steel puncher was used to punch a 9.0 mm diameter circular hole on the plate, and then 0.1 g of the fish scale biochar antibacterial adsorption material prepared in Example 1 was poured into the hole, and finally placed in a 37 ° C incubator for 18 h. The diameters of the inhibition zones of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were measured with a ruler to be 27 mm, 25 mm and 38 mm, respectively.

[0079] Antibacterial rate application test: Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa colonies were selected and placed in LB liquid culture medium (yeast powder 5g / L, sodium chloride 10g / L, beef peptone 10g / L), and cultured at 37°C. When the viable bacterial concentration of the culture medium reached 1.0×10 8 cfu / mL, 0.2 g / L of the fish scale biochar antibacterial adsorption material prepared in Example 1 was added, and the shaking culture was continued for 9 hours to obtain a bacterial suspension. Subsequently, 0.1 mL of the bacterial suspension was gradiently diluted with 0.9% sterile saline, and the number was counted by the plate count method, and the antibacterial rate of the fish scale biochar antibacterial adsorption material in the water was calculated to be above 99.9%.

[0080] Figure 3The repeated use of the fish scale biochar antibacterial adsorption materials prepared in Example 1 (a), Comparative Example 1 (b), Comparative Example 2 (c), and Comparative Example 3 (d) in water bodies is compared. It can be seen that the fish scale biochar antibacterial adsorption material prepared in Example 1 still maintains an antibacterial rate of more than 99.9% for Pseudomonas aeruginosa when it is reused 20 times; the antibacterial rate for Escherichia coli decreases significantly when it is reused 16 times, and when it is reused 20 times, its antibacterial rate remains at 94.5%; the antibacterial rate for Staphylococcus aureus decreases significantly when it is reused 9 times, and when it is reused 20 times, its antibacterial rate remains at 86.2%, which is significantly better than Comparative Examples 1-3. Among them, the antibacterial rate of the fish scale biochar antibacterial adsorption material prepared in Comparative Example 1 for Escherichia coli decreases significantly after the 10th repetition, the 5th for Staphylococcus aureus, and the 12th for Pseudomonas aeruginosa. This shows that the fish scale biochar antibacterial adsorption material of the present invention has good cyclic stability and long-term effectiveness.

[0081] Heavy metal ion adsorption application test: Use ultrapure water to prepare lead nitrate mother liquor (1000 mg / L), mercury nitrate mother liquor (1000 mg / L), chromium nitrate mother liquor (600 mg / L), cadmium nitrate mother liquor (600 mg / L) and copper nitrate mother liquor (600 mg / L). In subsequent experiments, the above mother liquors were diluted 10 times, that is, Pb 2+ , Hg 2+ Cr 3+ 、Cd 2+ and Cu 2+ The initial mass concentrations of the solutions were 100 mg / L, 100 mg / L, 60 mg / L, 60 mg / L and 60 mg / L, respectively. 20 mL of the above heavy metal ion solutions were respectively measured and added to 50 mL centrifuge tubes, and then 10 mg of the fish scale biochar antibacterial adsorption material of Example 1 was added to the centrifuge tubes. After mixing evenly, the centrifuge tubes were placed in a constant temperature shaking table (25°C, 200 r / min) for 1-11 hours. Figure 4 It can be seen that the adsorption basically reached equilibrium after 9 hours of oscillation, and the remaining Pb in the water sample was determined. 2+ , Hg 2+ Cr 3+ 、Cd 2+ and Cu 2+ The mass concentrations of the biochar were 12 mg / L, 10 mg / L, 14 mg / L, 13 mg / L and 15 mg / L, respectively, and the calculated adsorption rates were 88%, 90%, 77%, 79% and 75%, respectively. The results show that the fish scale biochar antibacterial adsorption material of the present invention has good adsorption properties for various ions, and the adsorption rates are all above 75%. The adsorption efficiencies of the biochar antibacterial adsorption materials of comparative examples 1-3 are basically the same, among which Pb in comparative example 1 is 2+ , Hg 2+ Cr3+ 、Cd 2+ and Cu 2+ The residual mass concentrations are 11 mg / L, 9 mg / L, 14 mg / L, 14 mg / L and 13 mg / L respectively. It can be seen that the adsorption performance of Comparative Examples 1-3 is not much different from that of Example 1. The possible reason is that the adsorption of heavy metal ions is mainly completed by the porous structure of fish scale biochar.

Claims

1. Application of a fish scale biochar antibacterial adsorption material, characterized in that, application of the fish scale biochar antibacterial adsorption material in antibacterial treatment of heavy metal wastewater; The preparation method of the fish scale biochar antibacterial adsorption material comprises the following steps: Wash the surface mud and mucus of fresh fish scales with clean water, then soak the fish scales in a sodium hydroxide solution with a mass concentration of 1% and stir for 24 h, then rinse with clean water until the supernatant is neutral as measured by a pH test paper. After sufficient rinsing, lift the fish scales out of the water and drain for 15 - 20 min. Place the pretreated fish scales in a tube furnace, heat to 300 °C at a heating rate of 10 °C / min under an inert atmosphere for carbonization for 2 h, naturally cool to room temperature, grind and sieve to obtain fish scale biochar; Soak 5 g of fish scale biochar in 100 mL of a silver nitrate solution with a concentration of 0.5 g / L in the dark and stir for 2 h, then add 0.2 g of trisodium citrate dihydrate and continuously stir for 24 h for reduction to obtain fish scale biochar loaded with nano - silver; Filter and dry the fish scale biochar loaded with nano - silver, then place it in a tube furnace, heat to 250 °C at a heating rate of 10 °C / min under an inert atmosphere for calcination for 2 h, naturally cool to room temperature, grind and sieve to obtain the fish scale biochar antibacterial adsorption material.

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