Porous carbon adsorbent derived from skin collagen as well as preparation method and application of porous carbon adsorbent

Abstract

The invention discloses a preparation method of a porous carbon adsorbent for treating antibiotics in water, and belongs to the technical field of environmental protection. Comprising the following steps: (1) adding a leather collagen fiber in the tanning field as a carbon source into deionized water to form a mixed solution, adding titanium sulfate under an acidic condition for tanning, obtaining a precipitate through a high-temperature water bath, washing with deionized water, and freeze-drying to obtain a porous carbon adsorbent precursor; (2) performing high-temperature carbonization on the precursor obtained in the step (1) in an inert atmosphere to obtain a compound of the titanium oxide and the carbon material; and (3) etching the compound in the step (2) with hydrofluoric acid, washing with deionized water, and drying to obtain the porous carbon adsorbent. The raw materials are wide in source, the preparation method is simple, and antibiotics in water can be efficiently adsorbed.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection technologies, and relates to a porous carbon adsorbent for treating antibiotics in water, a preparation method thereof, and an application thereof. Background Art

[0002] Antibiotics are synthetic broad-spectrum bactericidal drugs, which are widely used in the pharmaceutical, livestock, and aquaculture industries. Pharmaceutical industrial parks are important sources of antibiotic emissions. The residual concentration of antibiotics in the tail water after biochemical treatment of pharmaceutical wastewater is relatively high, and it is difficult to achieve complete removal through traditional methods such as adsorption, coagulation, and membrane separation. Antibiotics are difficult to decompose, and their biological properties can affect the growth and metabolism of aquatic organisms, and may also cause drug resistance in germs, posing a major threat to human health and the ecological system. Therefore, the development of water body antibiotic treatment technologies is of great significance for environmental protection and reducing the accumulation of antibiotics in water bodies.

[0003] Common antibiotic degradation methods include biological methods, chemical methods, and adsorption methods. The biological treatment method is a wastewater treatment method that uses microorganisms in the natural environment to oxidize and decompose organic matter and certain inorganic poisons (such as cyanide and sulfide) in wastewater and convert them into stable and harmless inorganic substances. However, the cost of strain screening and research in the biological method is relatively high. Special screening and research are required for degradation strains for different antibiotics, which takes a long time. The effect of antibiotic degradation by the biological method is affected by factors such as temperature, pH, and nutrients, and is not easy to control. The biological method for degrading antibiotics has certain limitations in the treatment scale and is difficult to cope with large-scale pollution. The chemical treatment method is a wastewater treatment method that separates and removes pollutants in the form of dissolved and colloidal states in wastewater or converts them into harmless substances through chemical reactions and mass transfer. Chemical methods may require the use of advanced equipment and reagents, resulting in an increase in treatment costs. Chemical methods may also produce toxic by-products, posing a potential threat to the environment and human health. Excessive use of chemical methods to degrade antibiotics may lead to the generation and spread of drug-resistant strains. As a simple and efficient method, the adsorption method can effectively remove antibiotics in wastewater, with good degradation effects, and the adsorption method is applicable to different types of wastewater and has no special requirements for the types of antibiotics. Compared with other degradation methods, the adsorption method has a lower cost and higher economic efficiency.

[0004] In summary, it is of great significance to develop an efficient and simple antibiotic adsorbent. Summary of the Invention

[0005] The purpose of the present invention is to provide a porous carbon adsorbent derived from skin collagen for efficiently adsorbing antibiotics in water and a preparation method thereof. A composite of titanium oxide and carbon materials is prepared by methods such as tanning and high-temperature carbonization, and a porous carbon adsorbent is prepared by etching titanium oxide with hydrofluoric acid for efficiently and rapidly adsorbing antibiotics to solve the problems of poor adsorption effect and long adsorption time existing in the existing adsorption method.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] (1) Add leather collagen fibers in the leather-making field as a carbon source to deionized water to form a mixed solution. Add titanium sulfate under acidic conditions for tanning, obtain a precipitate through a high-temperature water bath, wash with deionized water, and then perform freeze-drying to obtain a porous carbon adsorbent precursor;

[0008] (2) Subject the precursor obtained in (1) to high-temperature carbonization under an inert atmosphere to obtain a composite of titanium oxide and carbon material;

[0009] (3) Etch the composite in (2) with hydrofluoric acid and dry to obtain a porous carbon adsorbent.

[0010] The dosage of collagen fibers in step (1) is 15 g, the dosage of titanium sulfate is 15 g, and the dosage of deionized water is 400 ml.

[0011] In step (1), hydrochloric acid or sodium hydroxide is used to adjust the pH value of the mixed solution to 2.

[0012] The tanning time in step (1) is 4 h, the temperature of the high-temperature water bath is 90 °C, and the time is 12 h.

[0013] In step (1), a freeze dryer is used for freeze-drying, and the drying time is 48 h.

[0014] In step (2), the high-temperature carbonization step is to raise the temperature from room temperature to 100 °C at a heating rate of 3 °C / min, hold for 60 min, raise the temperature from 100 °C to 300 °C at a heating rate of 3 °C / min, hold for 120 min, raise the temperature from 300 °C to 1000 °C at a heating rate of 3 °C / min, and hold for 240 h.

[0015] In step (3), 50% hydrofluoric acid is used for etching, the etching time is 48 h, a drying oven is used for drying, the drying temperature is 60 °C, and the drying time is 8 h.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The porous adsorbent of the present invention has a large specific surface area, a developed pore structure, and involves both micropores and mesopores.

[0018] The reaction conditions of the present invention have low requirements for equipment, a high yield, and are suitable for industrial production.

[0019] The present invention has screened appropriate components and appropriate reaction parameters through a large number of experiments, and obtained a porous adsorbent with the best adsorption effect. Description of the Drawings

[0020] Figure 1 . Digital photo of the collagen-derived porous carbon adsorbent prepared in Example 1.

[0021] Figure 2 . XRD pattern of the collagen-derived porous carbon adsorbent prepared in Example 1.

[0022] Figure 3 . SEM image of the collagen-derived porous carbon adsorbent prepared in Example 1.

[0023] Figure 4 . Performance graph of the collagen-derived porous carbon adsorbent prepared in Example 1 for adsorbing sulfamethoxazole at 25 °C, 35 °C and 45 °C. Detailed implementation mode

[0024] The preparation method, material characterization and application of the collagen-derived porous carbon adsorbent will be further described below with reference to the accompanying drawings:

[0025] Preparation method:

[0026] Using leather collagen fibers in the leather-making field as the carbon source, weigh 15 g of leather collagen fibers and 6 g of NaCl and add them to 400 ml of deionized water to form a mixed solution. Use HCl to adjust the pH value of the mixed solution to 2, then add 15 g of Ti(SO4)2 for tanning, and the tanning time is 4 h. Then use NaHCO3 to slowly adjust the pH value of the mixed solution to 4 and continue stirring for 2 h. Then use an oil bath heater to heat up the mixed solution to 90 °C and keep it warm for 12 h. Then collect the precipitate after the reaction, wash it 3 times with deionized water and put it into a freeze dryer for freeze drying to obtain a porous carbon adsorbent precursor. Use a tube furnace to carry out high-temperature carbonization of the precursor under an inert atmosphere to obtain a composite of titanium oxide and carbon material. The high-temperature carbonization temperature is 1000 °C, the heating rate is 3 °C / min, and the holding time is 4 h. Use 50% hydrofluoric acid to etch the composite, and the etching time is 48 h. After etching, use a vacuum filter for filtration, and finally use a drying oven to dry at 60 °C for 8 h to obtain a porous carbon adsorbent.

[0027] Material characterization:

[0028] Figure 2 XRD diffraction pattern of the prepared porous carbon adsorbent. As can be seen from the figure, there are two broad peaks in the XRD diffraction pattern, corresponding to the (002) and (101) crystal planes of graphite (PDF#65-6212) respectively, indicating that the crystallinity of the porous carbon adsorbent is relatively low and it is mainly amorphous carbon.

[0029] Figure 3SEM images of the prepared porous carbon adsorbent. (a), (b), (c), and (d) are the morphology images magnified 5000 times, 10000 times, 50000 times, and 150000 times in sequence. From Figures (a) and (b), it can be seen that the prepared porous carbon adsorbent retains the structure of collagen fibers, but the length becomes shorter, with a diameter of 2 - 4 micrometers. And from Figures (c) and (d), it can be observed that there are many micropores on the surface of the adsorbent, indicating that voids are left on the surface of the carbon material after titanium oxide etching, increasing the specific surface area of the carbon material and being beneficial to the adsorption of antibiotics.

[0030] Application:

[0031] Figure 4 Performance graph of the porous carbon adsorbent for adsorbing the antibiotic sulfamethoxazole. The adsorption experiment was carried out in a 50 mL centrifuge tube. The volume of the pollutant solution was 50 mL, the concentration was 30 mg / L, the pH of the adsorption reaction was 7, the dosage of the porous carbon adsorbent was 5 mg, and a magnetic stirrer was used for stirring and heating, with a stirring rate of 600 r / min. Its adsorption performance was measured at 25 °C, 35 °C, and 45 °C respectively. After the experiment started, samples were taken at 0 min, 2 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 70 min, and 90 min respectively. After filtration, the concentration of sulfamethoxazole was measured using an ultraviolet spectrophotometer. From Figure 4 it can be seen that at the three temperatures, the porous adsorbent can reach the maximum adsorption within 50 minutes, and the adsorption performance increases with the increase in temperature. The equilibrium adsorption capacity at 45 °C can reach 206 mg / g. It shows that the porous adsorbent has good adsorption effects on sulfamethoxazole at different temperatures.

Claims

1. A porous carbon adsorbent derived from skin collagen, its preparation method and application, characterized in that, It includes the following parts: (1) Add leather collagen fibers in the leather-making field as a carbon source to deionized water to form a mixed solution. Add titanium sulfate under acidic conditions for tanning, obtain a precipitate through a high-temperature water bath, wash with deionized water, and then perform freeze-drying to obtain a porous carbon adsorbent precursor; (2) Carry out high-temperature carbonization of the precursor obtained in (1) under an inert atmosphere to obtain a composite of titanium oxide and carbon material; (3) Etch the composite in (2) with hydrofluoric acid, wash with deionized water, and dry to obtain a porous carbon adsorbent.

2. The preparation method according to claim 1, characterized in that, The dosage of collagen fibers in step (1) is 15 g, the dosage of titanium sulfate is 15 g, and the dosage of deionized water is 400 ml.

3. The preparation method according to claim 1, characterized in that, In step (1), hydrochloric acid or sodium hydroxide is used to adjust the pH value of the mixed solution to 2.

4. The preparation method according to claim 1, characterized in that, The tanning time in step (1) is 4 h, the temperature of the high-temperature water bath is 90 °C, and the time is 12 h.

5. The preparation method according to claim 1, characterized in that, In step (1), a freeze dryer is used for freeze-drying, and the drying time is 48 h.

6. The preparation method according to claim 1, characterized in that, In step (2), the high-temperature carbonization step is to heat from room temperature to 100 °C at a heating rate of 3 °C / min, hold for 60 min, heat from 100 °C to 300 °C at a heating rate of 3 °C / min, hold for 120 min, heat from 300 °C to 1000 °C at a heating rate of 3 °C / min, and hold for 240 h.

7. The preparation method according to claim 1, characterized in that, In step (3), 50% hydrofluoric acid is used for etching, the etching time is 48 h, a freeze-drying oven is used for drying, the drying temperature is 60 °C, and the drying time is 8 h.

8. A porous carbon adsorbent derived from skin collagen, its preparation method according to any one of claims 1 to 7, characterized in that, The pollutants targeted by the porous carbon adsorbent are antibiotics in water.

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