Application of biomass porous carbon in tetracycline medicine wastewater treatment
By adsorbing tetracycline drug wastewater with biomass porous carbon adsorbent, the problem that existing water treatment processes are difficult to effectively remove antibiotics is solved, and the efficient and low-cost water treatment effect is achieved, which meets the requirements of green and environmental protection.
Patent Information
- Application Number
- CN202510521000.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2025-06-13
AI Technical Summary
The existing water treatment process is difficult to effectively remove antibiotics in tetracycline-based drug wastewater, and it is costly, has high equipment technical requirements and poor economicality.
By using biomass such as corn cobs and reed bamboo as raw materials, a high specific surface area biomass porous carbon adsorbent is prepared through steps such as phosphoric acid activation and muffle furnace calcination, which has excellent adsorption properties for tetracycline drugs.
The prepared biomass porous carbon adsorbent significantly improves the saturation adsorption capacity of tetracycline hydrochloride and oledrinone hydrochloride, which is cheap and simple in process, which meets the development concept of green and environmental protection, laying the foundation for large-scale industrial applications.
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Figure CN120132791A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the preparation of a biomass porous carbon and its application in the treatment of tetracycline pharmaceutical wastewater, belonging to the technical field of water treatment. Background Art
[0002] Antibiotics are used to treat bacterial infections and inhibit microorganisms, and are widely used in medical and agricultural production. The residual antibiotics in antibiotic pharmaceutical wastewater pose a threat to the water environment and human health, and even induce the generation of drug-resistant bacteria, ultimately leading to the transfer and spread of antibiotic-resistant genes, greatly damaging the natural bacterial ecosystem and posing a potentially serious threat to the ecological environment and human health. Unfortunately, the existing water treatment processes generally have high costs for completely removing antibiotics, high equipment technical requirements, and poor economy. The adsorption method uses porous materials to adsorb pollutants in wastewater and achieves the purpose of pollutant removal through separation. Compared with other separation methods, the adsorption method is simple, efficient, low-cost, highly applicable, and does not produce any by-products, and has broad application prospects in the field of water treatment. Biomass resources are renewable, contain various elements such as carbon, nitrogen, and phosphorus, have rich surface functional groups, low cost, and wide sources, and are good precursors for preparing porous carbon material adsorbents.
[0003] The present invention prepares a high specific surface area biomass porous carbon adsorbent using biomass such as corncobs and giant reed as raw materials through steps such as phosphoric acid activation, muffle furnace calcination, and alkali washing. The experimental results show that the specific surface area of corncob powder is 1.4 m 2 / g, and the specific surface areas of water-activated and phosphoric acid-activated corncob porous carbons are 64.3 m 2 / g and 1246.8 m 2 / g respectively. After phosphoric acid activation, the specific surface area of corncob porous carbon increases significantly, and the surface is rich in functional groups such as hydroxyl and carbonyl. The saturated adsorption capacities for tetracycline hydrochloride and oxytetracycline hydrochloride reach 356.12 mg / g and 397.58 mg / g respectively, which are much higher than those of corncob powder and water-activated corncob porous carbon. The saturated adsorption amounts of tetracycline hydrochloride and oxytetracycline hydrochloride using phosphoric acid-activated giant reed porous carbon reach 569.24 mg / g and 544.05 mg / g respectively, which are much higher than those of giant reed powder. The purpose of the present invention is to develop a low-cost biomass porous carbon adsorbent for the treatment of tetracycline pharmaceutical wastewater, which has the characteristics of low cost, simple process, and excellent adsorption performance, and can be used to effectively adsorb tetracycline pharmaceutical wastewater. Summary of the Invention
[0004] The present invention uses corncob and giant reed as biomass raw materials to prepare biomass porous carbon through phosphoric acid activation and muffle furnace calcination, and has excellent adsorption performance for tetracycline antibiotics such as tetracycline hydrochloride and oxytetracycline hydrochloride. The adsorbent of the present invention is prepared through the following steps:
[0005] (1) First, clean, dry, crush, and sieve the biomass raw material to obtain biomass powder;
[0006] (2) Add the phosphoric acid aqueous solution to the biomass powder, mix well, and activate it;
[0007] (3) Transfer the biomass powder activated by phosphoric acid to a crucible, cover it, and calcine it in a muffle furnace;
[0008] (4) Wash the calcined material until it is neutral, then dry and grind it to obtain the biomass porous carbon adsorbent;
[0009] (5) After mixing the biomass porous carbon adsorbent with the tetracycline hydrochloride solution or oxytetracycline hydrochloride solution until adsorption equilibrium is reached, use an ultraviolet-visible spectrophotometer to measure the concentration of the remaining substrate in the solution before and after adsorption, and calculate the equilibrium adsorption capacity.
[0010] Preferably, in step (1), the biomass raw material is one of corncobs and giant reed, the drying condition is to keep it in an oven at 50 - 70 °C for 12 - 48 h, and the mesh number of the sieve used is 60 - 100.
[0011] Preferably, in step (2), the mass of the biomass powder used is 1 - 6 g, the mass fraction of the phosphoric acid aqueous solution is 70 - 85%, the mass of the phosphoric acid aqueous solution is 2.5 - 15 g, the stirring method is stirring with a glass rod, the stirring time is 10 - 30 min, the activation temperature is 15 - 35 °C, and the activation time is 12 - 72 h.
[0012] Preferably, in step (3), the calcination temperature of the muffle furnace is 250 - 350 °C, the calcination time is 1 - 3 h, the heating rate is 5 - 10 °C / min, and the crucible lid is half-covered or fully covered.
[0013] Preferably, in step (4), the washing method is water washing or alkaline washing with a 0.01 - 0.2 mol / L sodium hydroxide aqueous solution, and the washing temperature is 20 - 70 °C.
[0014] Preferably, in step (5), the mass of the adsorbent powder is 0.005 - 0.02 g, the concentration of the tetracycline hydrochloride aqueous solution is 50 - 400 mg / L and the volume is 10 - 40 mL, the concentration of the oxytetracycline hydrochloride aqueous solution is 50 - 400 mg / L and the volume is 10 - 40 mL. The mixing method of the adsorbent and the tetracycline solution is stirring or shaking, the mixing temperature is 20 - 50 °C, and the mixing time is 24 - 48 h.
[0015] Compared with the prior art, the main innovation points of the present invention are as follows: Using waste biomass as the precursor of porous carbon, which has a wide source and low cost. The biomass porous carbon activated by medium-strong acid phosphoric acid has a high specific surface area, large porosity, rich functional groups, and good chemical stability. The equilibrium adsorption capacities of corn cob powder, water-activated corn cob porous carbon, and phosphoric acid-activated corn cob porous carbon for tetracycline hydrochloride with an initial concentration of 200 mg / L are 2.49 mg / g, 90.21 mg / g, and 356.12 mg / g, respectively. The equilibrium adsorption capacities of corn cob powder, water-activated corn cob porous carbon, and phosphoric acid-activated corn cob porous carbon for oxytetracycline hydrochloride with an initial concentration of 200 mg / L are 3.11 mg / g, 85.91 mg / g, and 397.58 mg / g, respectively. The results show that the adsorption performance of phosphoric acid-activated corn cob porous carbon is significantly better than that of corn cob powder and water-activated corn cob porous carbon. The saturated adsorption capacities of the corn cob porous carbon adsorbent for tetracycline hydrochloride and oxytetracycline hydrochloride, calculated according to the Langmuir model fitting, are as high as 559.88 mg / g and 520.81 mg / g, respectively. The saturated adsorption capacities of the Arundo donax porous carbon prepared by this method for tetracycline hydrochloride and oxytetracycline hydrochloride, obtained by Langmuir fitting, are 569.24 mg / g and 544.05 mg / g, respectively, which are much higher than those of Arundo donax powder. This method involves inexpensive and easily available raw materials, a simple preparation method, excellent adsorption performance, can greatly reduce the production cost of the adsorbent, and the preparation method meets the development concept of green environmental protection, laying a foundation for large-scale industrial application. Description of the Drawings
[0016] Figure 1 Scanning electron microscope photograph of corn cob powder CC in Comparative Example 1
[0017] Figure 2 Scanning electron microscope photograph of the phosphoric acid-activated corn cob porous carbon adsorbent CC-P prepared in Example 1
[0018] Figure 3 FTIR spectra of corn cob CC, water-activated corn cob porous carbon CC-W, and phosphoric acid-activated corn cob porous carbon CC-P
[0019] Figure 4 Specific surface area and pore size distribution diagram of water-activated corn cob porous carbon CC-W
[0020] Figure 5 Specific surface area and pore size distribution diagram of phosphoric acid-activated corn cob porous carbon CC-P
[0021] Figure 6Adsorption capacity comparison of corncob CC, water-activated corncob porous carbon CC-W, and phosphoric acid-activated corncob porous carbon CC-P for tetracycline hydrochloride aqueous solution with an initial concentration of 200 mg / L
[0022] Figure 7 Adsorption capacity comparison of corncob CC, water-activated corncob porous carbon CC-W, and phosphoric acid-activated corncob porous carbon CC-P for oxytetracycline hydrochloride aqueous solution with an initial concentration of 200 mg / L
[0023] Figure 8 Adsorption thermodynamic isotherm of phosphoric acid-activated corncob porous carbon CC-P prepared in Example 1 for tetracycline hydrochloride with different concentrations at 20 °C under stirring for 24 h
[0024] Figure 9 Adsorption thermodynamic isotherm of phosphoric acid-activated corncob porous carbon CC-P prepared in Example 1 for oxytetracycline hydrochloride with different concentrations at 20 °C under stirring for 24 h
[0025] Figure 10 Adsorption thermodynamic isotherm of phosphoric acid-activated Arundo donax porous carbon GA-P prepared in Example 2 for tetracycline hydrochloride with different concentrations at 20 °C under stirring for 24 h
[0026] Figure 11 Adsorption thermodynamic isotherm of phosphoric acid-activated Arundo donax porous carbon GA-P prepared in Example 2 for oxytetracycline hydrochloride with different concentrations at 20 °C under stirring for 24 h
[0027] Figure 12 Adsorption capacity comparison of Arundo donax powder GA, phosphoric acid-activated Arundo donax porous carbon GA-P for tetracycline hydrochloride and oxytetracycline hydrochloride aqueous solutions with an initial concentration of 200 mg / L Detailed implementation manners
[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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.
[0029] Comparative Example 1: Adsorption of tetracycline hydrochloride and oxytetracycline hydrochloride by corncob powder
[0030] (1) The corncob was washed, dried, crushed, and sieved to obtain a biomass powder, denoted as CC.
[0031] (2) In a 50 mL centrifuge tube, weigh 10 mg of CC by the difference method on an analytical balance into the centrifuge tube, and add 20 mL of the prepared 200 mg / L aqueous solution of tetracycline hydrochloride. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, discard the first three drops, then perform an absorbance test using a UV-visible spectrophotometer, substitute it into the standard working curve of tetracycline hydrochloride, and obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0032] (3) In a 50 mL centrifuge tube, weigh 10 mg of CC by the difference method on an analytical balance into the centrifuge tube, and add 20 mL of the prepared 200 mg / L aqueous solution of oxytetracycline hydrochloride. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, discard the first three drops, then perform an absorbance test using a UV-visible spectrophotometer, substitute it into the standard working curve of oxytetracycline hydrochloride, and obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0033] Comparative Example 2: Adsorption of Tetracycline Hydrochloride and Oxytetracycline Hydrochloride by Water-Activated Biomass Porous Carbon
[0034] (1) Wash the corn cob, dry it, crush it, and sieve it to obtain biomass powder, denoted as CC.
[0035] (2) Weigh a certain amount of 2 g of corn cob powder CC in a 50 mL beaker, add 5 g of deionized water, stir with a glass rod for 30 min, then seal it with plastic wrap and place it in a fume hood for activation for 24 h.
[0036] (3) Transfer the activated corn cob powder to a crucible, place it in a muffle furnace, and heat it to 300 °C at a rate of 5 °C / min under the condition of full covering, keep it warm for 1 h and then take it out.
[0037] (4) Grind the calcined corn cob porous carbon and put it into a beaker, add a NaOH solution with a concentration of 0.1 mol / L, perform alkali washing with magnetic stirring at 60 °C, stir well for 1 h, then wash and filter by suction until neutral, place it in an oven at 70 °C for drying for 24 h, then take it out and grind it, weigh the mass of the product and put it into a sample tube, denoted as CC-W.
[0038] (5) In a 50 mL centrifuge tube, weigh 10 mg of CC-W by the difference method on an analytical balance into the centrifuge tube, and add 20 mL of the prepared 200 mg / L aqueous solution of tetracycline hydrochloride. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, perform an absorbance test, substitute it into the standard working curve of tetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0039] (6) In a 50 mL centrifuge tube, weigh 10 mg CC-W on an analytical balance using the differential method, add 20 mL of a prepared 200 mg / L oxytetracycline hydrochloride aqueous solution, mix, add a stirrer and stir at 20 °C for 24 h. After adsorption, quickly draw the liquid with a syringe, filter with a membrane to obtain a clear liquid, perform an absorbance test, and substitute it into the standard working curve of oxytetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption amount.
[0040] Example 1: Phosphoric acid activated corncob porous carbon adsorbs tetracycline hydrochloride and oxytetracycline hydrochloride
[0041] (1) Corn cobs are cleaned, dried, crushed, and sieved to obtain biomass powder, which is recorded as CC.
[0042] (2) Weigh 2 g corncob powder CC in a 50 mL beaker, add 5 g of 85% phosphoric acid aqueous solution, stir with a glass rod for 30 min, then seal with plastic wrap and place in a fume hood for activation for 24 h.
[0043] (3) The activated corncob powder was transferred to a crucible, placed in a muffle furnace, and heated to 300°C at a rate of 5°C / min under full cover conditions. The crucible was kept at this temperature for 1 hour and then taken out.
[0044] (4) Grind the corncob porous carbon after calcination and put it into a beaker, add a 0.1 mol / L NaOH solution at 60°C for alkaline washing, stir it for 1 hour, and then wash and filter it until it is neutral.
[0045] (5) The corn cob porous carbon was placed in an oven at 70°C and dried for 24 h. The product was then taken out and ground. The product was weighed and placed in a sample tube, which was recorded as CC-P.
[0046] (6) In five 50 mL centrifuge tubes, weigh 10 mg CC-P on an analytical balance using the differential method, and add 20 mL of prepared 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L tetracycline hydrochloride aqueous solutions in sequence. After mixing, add a stirrer and stir at 20 °C for 24 h. After the adsorption is completed, quickly draw the liquid with a syringe, filter it with a filter membrane to obtain the clear liquid, perform an absorbance test, and substitute it into the standard working curve of tetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption amount.
[0047] (7) In five 50 mL centrifuge tubes, weigh 10 mg of CC-P in each centrifuge tube by the difference method on an analytical balance. Then, successively add 20 mL of the prepared oxytetracycline hydrochloride aqueous solutions with concentrations of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, perform absorbance tests, substitute the values into the standard working curve of oxytetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0048] Example 2: Adsorption of tetracycline hydrochloride and oxytetracycline hydrochloride by phosphoric acid-activated Arundo donax porous carbon
[0049] (1) Wash the Arundo donax leaves, dry them, crush them, and sieve them to obtain Arundo donax-based powder, denoted as GA.
[0050] (2) Weigh 2 g of Arundo donax powder in a 50 mL beaker, add 5 g of 85% phosphoric acid aqueous solution, stir with a glass rod for 30 min, then seal it with plastic wrap and place it in a fume hood for activation for 24 h.
[0051] (3) Transfer the activated Arundo donax powder to a crucible, place it in a muffle furnace, and heat it to 300 °C at a rate of 5 °C / min under a semi-covered condition, and calcine for 1 h.
[0052] (4) Grind all the Arundo donax porous carbon after calcination and put it into a 250 mL round-bottomed flask, add a magnetic stir bar and 100 mL of 0.1
[0053] mol / L NaOH solution, wash it with alkali at 60 °C on a magnetic stirrer, stir well for 1 h, then take out the magnetic stir bar, wash and filter by suction until neutral.
[0054] (5) Put the washed Arundo donax porous carbon into an oven at 70 °C and dry it for 12 h. Then take it out, grind it, weigh the product, and put it into a sample tube for storage, denoted as GA-P.
[0055] (6) In five 50 mL centrifuge tubes, weigh 10 mg of GA-P in each centrifuge tube by the difference method on an analytical balance. Then, successively add 20 mL of the prepared tetracycline hydrochloride aqueous solutions with concentrations of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, and 400 mg / L. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, perform absorbance tests, substitute the values into the standard working curve of tetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0056] (7) In five 50 mL centrifuge tubes, weigh 10 mg of GA-P in each centrifuge tube by the difference method on an analytical balance. Then, successively add 20 mL of the prepared oxytetracycline hydrochloride aqueous solutions with concentrations of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, and 400 mg / L. After mixing, add a magnetic stir bar and stir at 20 °C for 24 h. After the adsorption is completed, quickly suck the liquid with a syringe, filter it through a filter membrane to obtain a clear liquid, measure the absorbance, substitute it into the standard working curve of oxytetracycline hydrochloride to obtain the concentration after adsorption, and calculate the equilibrium adsorption capacity.
[0057] Performance Characterization of Materials
[0058] (1) Morphology Characterization (SEM and TEM)
[0059] Figure 1 It shows that the overall microstructure of the corncob powder CC in Comparative Example 1 exists in a banded form, is loose and porous, and its surface is generally smooth and dense. Figure 2 It shows that the porous corncob carbon CC-P prepared in Example 1 retains the porous structure of CC, the banded structure disappears, presenting an aggregated granular shape, with a rough surface and a large number of small pores, and a higher porosity.
[0060] (2) Fourier Transform Infrared Spectroscopy Analysis (FTIR)
[0061] Perform FTIR characterization on the obtained adsorbent samples to analyze their functional groups. The results are as Figure 3 shown. According to the FTIR spectrum, CC-P has peak bands at 3422 cm -1 , 2924 cm -1 , 2840 cm -1 , 1704 cm -1 , 1619 cm -1 , which correspond to -OH, -CH 3 , -CH 2 -, -C=O, and benzene ring. The peak band at 1398 cm -1 and the stretching vibrations of -CH 3 , -CH 2 - are related. The peak bands at 604 cm -1 and 536 cm -1 are related to the asymmetric vibration of P=O. Compared with CC-P, the peak bands of -OH and -CH 3 in CC still exist, and there is also C-O at 1032 cm -1 . This indicates that the functional groups of CC-P have changed compared with those of CC.
[0062] (3) Specific Surface Area and Pore Size Analysis (BET)
[0063] The specific surface area of the obtained adsorbent sample was measured. Comparative Example 2 (CC-W) was used as a control. Compared with CC-P, it can be clearly seen that phosphoric acid plays a key role in the activation of corn cob porous carbon. The multi-point BET specific surface area of the untreated corn cob powder is 1.4 m 2 / g. After changing the activation from water to phosphoric acid, the multi-point BET specific surface area of the corn cob porous carbon increased from 64.3 m 2 / g to 1246.8 m 2 / g, an increase of 18.4 times. The cumulative mesopore and macropore internal surface area of BJH adsorption increased by 449.32%, and the cumulative mesopore and macropore internal surface area of BJH desorption increased by 362.12%. The total adsorption pore volume increased from 0.092 cm 3 / g to 0.966 cm 3 / g. The total micropore volume increased from 0.0265 cm 3 / g to 0.4938 cm 3 / g. It can be seen that phosphoric acid activation greatly increases the specific surface area and pore structure of corn cob porous carbon, which is helpful for the adsorption process.
[0064] (4) Adsorption performance experiment
[0065] In three 50 mL centrifuge tubes, 20 mL of 200 mg / L tetracycline hydrochloride solution was added respectively. Then 10 mg of corn cob powder CC, water-activated corn cob porous carbon CC-W, and phosphoric acid-activated corn cob porous carbon CC-P were added in sequence. The adsorption amounts at adsorption equilibrium were measured as shown in Figure 6 . Through the control experiment, the adsorption amounts of CC, CC-W, and CC-P for tetracycline hydrochloride were 2.49 mg / g, 90.21 mg / g, and 356.12 mg / g respectively. In three 50 mL centrifuge tubes, 20 mL of 200 mg / L oxytetracycline hydrochloride solution was added respectively. Then 10 mg of corn cob powder CC, water-activated corn cob porous carbon CC-W, and phosphoric acid-activated corn cob porous carbon CC-P were added in sequence. The adsorption amounts at adsorption equilibrium were measured as shown in Figure 7 . The adsorption amounts of CC, CC-W, and CC-P for oxytetracycline hydrochloride were 3.11 mg / g, 85.91 mg / g, and 397.58 mg / g respectively. Phosphoric acid activation has a key influence on the adsorption performance of biomass porous carbon, and the adsorption capacity is significantly higher than that of CC-W and CC.
[0066] Take 5 portions of 10 mg of the corncob porous carbon CC-P prepared in Example 1 in 5 centrifuge tubes of 50 mL. Respectively add tetracycline hydrochloride solutions of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L. After stirring at 20 °C for 24 h, suck the liquid with a syringe, and then use a filter head to filter to obtain a clear liquid. Test to obtain the ultraviolet-visible absorption spectrum, calculate the adsorption capacity at the adsorption equilibrium, and perform Langmuir model fitting on the obtained data. As Figure 8 shown, the saturated adsorption capacity q m = 559.88 mg / g, and the fitting correlation coefficient R 2 = 0.97782.
[0067] Take 5 portions of 10 mg of the corncob porous carbon CC-P prepared in Example 1 in 5 centrifuge tubes of 50 mL. Respectively add oxytetracycline hydrochloride solutions of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L. After stirring at 20 °C for 24 h, suck the liquid with a syringe, and then use a filter head to filter to obtain a clear liquid. Test to obtain the ultraviolet-visible absorption spectrum, calculate the adsorption capacity at the adsorption equilibrium, and perform Langmuir model fitting on the obtained data. As Figure 9 shown, the saturated adsorption capacity qm = 520.81 mg / g, and the fitting correlation coefficient R 2 = 0.97317.
[0068] Take 5 portions of 10 mg of the giant reed porous carbon GA-P prepared in Example 2 and place them in 5 centrifuge tubes of 50 mL respectively. Sequentially add tetracycline hydrochloride solutions of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, and 400 mg / L. After stirring at 20 °C for 24 h, suck the liquid with a syringe, and then use a filter head to filter to obtain a clear liquid. Test to obtain the ultraviolet-visible absorption spectrum, calculate the adsorption capacity at the adsorption equilibrium, and perform Langmuir model fitting on the obtained data. As Figure 10 shown, the saturated adsorption capacity qm = 569.25 mg / g, and the fitting correlation coefficient R 2 = 0.92436.
[0069] Take 5 portions of 10 mg of the giant reed porous carbon GA-P prepared in Example 2 and place them in 5 centrifuge tubes of 50 mL respectively. Sequentially add oxytetracycline hydrochloride solutions of 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, and 400 mg / L. After stirring at 20 °C for 24 h, suck the liquid with a syringe, and then use a filter head to filter to obtain a clear liquid. Test to obtain the ultraviolet-visible absorption spectrum, calculate the adsorption capacity at the adsorption equilibrium, and perform Langmuir model fitting on the obtained data. As Figure 11As shown, the saturated adsorption capacity q m = 544.05 mg / g, and the fitting correlation coefficient R 2 = 0.89417.
[0070] In two 50 mL centrifuge tubes, 20 mL of 200 mg / L tetracycline hydrochloride solution was added respectively. Then 10 mg of Arundo donax powder GA and 10 mg of phosphoric acid-activated Arundo donax porous carbon GA-P were added successively. The results of the adsorption amount at the adsorption equilibrium are as Figure 12 shown. Through the control experiment, the adsorption amounts of GA and GA-P for tetracycline hydrochloride were 8.8 mg / g and 305.32 mg / g respectively. In two 50 mL centrifuge tubes, 20 mL of 200 mg / L oxytetracycline hydrochloride solution was added respectively. Then 10 mg of Arundo donax powder GA and phosphoric acid-activated Arundo donax porous carbon GA-P were added successively. The results of the adsorption amount at the adsorption equilibrium are as Figure 12 shown. The adsorption amounts of GA and GA-P for oxytetracycline hydrochloride were 53 mg / g and 435.72 mg / g respectively. The adsorption capacity of the phosphoric acid-activated Arundo donax porous carbon GA-P was significantly higher than that of the Arundo donax powder GA.
Claims
1. The application of biomass porous carbon in the treatment of tetracycline drug wastewater includes the following steps: (1) First, the biomass raw material is cleaned, dried, crushed, and sieved to obtain biomass powder; (2) stirring and mixing the biomass powder and the phosphoric acid solution in a beaker for activation; (3) transferring the biomass powder activated by phosphoric acid into a crucible, covering it, and placing it in a muffle furnace for calcination; (4) washing the calcined material to neutrality, drying it, and grinding it to obtain a biomass porous carbon adsorbent; (5) After the biomass porous carbon adsorbent and the tetracycline hydrochloride aqueous solution or the oxytetracycline hydrochloride aqueous solution are mixed to reach adsorption equilibrium, the concentrations before and after adsorption are quantified using an ultraviolet-visible spectrophotometer to calculate the equilibrium adsorption amount.
2. The preparation method according to claim 1, characterized in that: The biomass raw material is one of corn cobs and reed bamboo, and the drying condition is to keep it in an oven at 50-70° C. for 12-48 hours, and the mesh number of the used sieve is 60-100.
3. The preparation method according to claim 1, characterized in that: The mass of biomass powder is 1-6g, the mass fraction of phosphoric acid aqueous solution is 70-85%, the mass of phosphoric acid aqueous solution is 2.5-15g, the stirring method is glass rod stirring, the stirring time is 10-40min, the activation temperature is 15-35℃, and the activation time is 12-72h.
4. The preparation method according to claim 1, characterized in that: The calcination temperature of the muffle furnace is 250-350°C, the heating rate is 5-10°C / min, and the crucible cover is half-covered or fully covered.
5. The preparation method according to claim 1, characterized in that: The washing method is water washing at 60°C or room temperature, and alkaline washing with 0.01-0.2 mol / L sodium hydroxide solution at 60°C or room temperature.
6. The preparation method according to claim 1, characterized in that: The mass ratio of the adsorbent powder is 0.005-0.02g, the concentration of the tetracycline hydrochloride aqueous solution is 50-400mg / L, the volume is 10-30mL, and the concentration of the oxytetracycline hydrochloride aqueous solution is 50-400mg / L, the volume is 10-30mL. The adsorbent and the tetracycline solution are mixed by stirring or shaking, the mixing temperature is 20-50°C, and the mixing time is 24-48h.