Method for preparing flower-shaped biochar balls and lignin-based carbon dots from waste distiller's grains in multiple scales and application thereof

Abstract

The application discloses a method for preparing flower-shaped biochar balls and lignin-based carbon dots from waste distiller's grains in multiple scales and application thereof. The application is based on the multiple-scale development and utilization of waste distiller's grains. Aluminum chloride hexahydrate and glycerol are used as a eutectic solvent to separate lignin from the distiller's grains, so that a mixed solution A of distiller's grains cellulose carbohydrates, lignin and the eutectic solvent is obtained. The mixed solution A is mixed with an acetone aqueous solution, and centrifugal separation is performed to obtain a mixed solution B of cellulose carbohydrates and lignin-eutectic solvent. After the acetone in the solution B is removed, a concentrated mixed solution B is obtained, and then a hydrothermal reaction is performed to obtain a lignin-based carbon dot solution. The distiller's grains cellulose carbohydrates are subjected to a hydrothermal reaction to obtain cellulose hydrothermal carbon balls. The cellulose hydrothermal carbon balls, melamine, cobalt acetate hexahydrate and potassium bicarbonate are uniformly mixed by co-grinding, and then pyrolysis is performed to obtain flower-shaped biochar ball catalysts. The waste distiller's grains are converted into the lignin-based carbon dot solution which can be applied to heavy metal ion sensing and the catalyst which can be applied to the remediation of organic pollutants in water bodies in multiple scales and high value, so that the comprehensive utilization rate of the waste distiller's grains is improved, and the application has remarkable resource and environmental values.

Description

Technical Field

[0001] This invention relates to the fields of biomass materials and water pollution control technology, and in particular to a method for preparing flower-shaped biochar balls and lignin-based carbon dots from waste distiller's grains at multiple scales and their applications. Background Technology

[0002] Baijiu (Chinese white liquor) is an alcoholic beverage made primarily from grains, using daqu (large koji), xiaoqu (small koji), bran koji, and yeast as saccharification and fermentation agents. The process involves cooking, saccharification, fermentation, and distillation. Distiller's grains (or lees) are the main waste product in baijiu production, with a ratio of approximately 1:3 between baijiu production and lees production. This vast quantity of lees is difficult to utilize, partly due to its high moisture and acidity, making it difficult to preserve, and partly due to its high rice husk content (approximately 75%), resulting in a high fiber content. Directly discarding lees not only severely pollutes the environment but also wastes a significant amount of resources. Research on the reuse of lees is of great importance, enabling not only the rational use of resources but also the green production of traditional baijiu, responding to the national call for sustainable development. Because lees contain abundant cellulose, lignin, and protein, and are widely available and inexpensive, they represent an ideal biomass resource for development. Effective development and utilization of lees, improving resource utilization rates, can not only reduce and prevent environmental pollution from waste lees but also bring significant economic benefits. In recent years, research on distillers' grains has mainly focused on their application in animal feed, anaerobic digestion technology, cellulose fermentation in distillers' grains to produce ethanol fuel, and extraction of high-value functional substances from distillers' grains. However, the amount of distillers' grains consumed in these applications accounts for only a small portion of the annual amount of distillers' grains waste. A large amount of distillers' grains waste still urgently needs to be treated. Therefore, it is still necessary to further develop new technologies for the utilization of distillers' grains, increase the utilization rate of distillers' grains waste, and alleviate the environmental pollution caused by distillers' grains.

[0003] Water bodies contain various organic pollutants and inorganic heavy metals from agriculture, industrial production, and other real-world environments. Water pollution caused by heavy metals and emerging organic pollutants has become one of the world's largest environmental challenges. In recent years, persulfate advanced oxidation technology has made significant progress in treating recalcitrant organic wastewater, offering advantages such as a wide pH range, strong oxidation capacity, and long half-life. While homogeneous persulfate systems using transition metal ions as catalysts have advantages such as high activation efficiency and low catalyst dosage, they also suffer from disadvantages such as difficult catalyst recovery, significant influence from solution pH, and the potential for secondary pollution. Therefore, there is a need to develop new heterogeneous catalytic systems based on catalyst activation. Rapid detection of heavy metal content in water bodies is of great importance. Conventional detection methods, such as flame atomic absorption spectrometry (FAAS) and inductively coupled plasma mass spectrometry (ICP-MS), suffer from cumbersome procedures, low sensitivity, or the need for expensive instruments. Carbon dot-based fluorescence analysis technology for detecting heavy metal ions has proven to be an effective method. Compared to traditional organic molecules as carbon sources for synthesizing carbon dots, biomass carbon sources have many advantages such as being environmentally friendly, low-cost, and biocompatible, attracting increasing attention. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a flower-shaped biochar ball catalyst with excellent persulfate activation effect and a lignin-based carbon quantum dot with high stability and good fluorescence sensing effect using waste distiller's grains at multiple scales.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows:

[0006] A method for preparing flower-shaped biochar balls and lignin-based carbon dots from waste distiller's grains at multiple scales includes the following steps:

[0007] (1) Aluminum chloride hexahydrate and glycerol were mixed, heated and stirred until homogeneous to obtain a pale yellow, transparent, viscous eutectic solvent;

[0008] (2) Add the lees powder to a eutectic solvent for lignin separation pretreatment. After the reaction is complete, a mixture A of lees cellulose carbohydrates, lignin and eutectic solvent is obtained.

[0009] (3) Pour the mixture A into an acetone aqueous solution, stir and then centrifuge. The remaining solution after centrifugation is evaporated and concentrated to remove the acetone, and a concentrated lignin-eutectic solvent mixture is obtained.

[0010] (4) Pour the concentrated lignin-eutectic solvent mixture obtained in step (3) into a polytetrafluoroethylene reactor for hydrothermal reaction. After the reaction is completed, filter to remove large particles, and after dialysis and filtration, obtain a light yellow transparent lignin-based carbon dot solution.

[0011] (5) The cellulose carbohydrates obtained in step (2) are subjected to hydrothermal reaction in a polytetrafluoroethylene reactor. After thorough washing and freeze-drying, cellulose hydrothermal carbon balls are obtained.

[0012] (6) The hydrothermal carbon balls obtained in step (5) are ground and mixed evenly with melamine, cobalt acetate hexahydrate and potassium bicarbonate to obtain a brown homogeneous mixture. Then, the mixture is pyrolyzed under nitrogen protection, ground, and acid-washed to neutral to obtain flower-shaped biochar ball catalyst.

[0013] According to the above scheme, in step (1), the molar ratio of aluminum chloride hexahydrate to glycerol is 1:(6-10); the heating temperature is 80℃, and the oil bath is used for constant temperature magnetic stirring for 1-2 hours.

[0014] According to the above scheme, in step (2), the solid-liquid mass ratio of the distiller's grains powder to the eutectic solvent is 1:(12-18); during the lignin separation pretreatment, a constant temperature oil bath with magnetic stirring at 80-130℃ is used for stirring for 1-9 hours.

[0015] According to the above scheme, in step (3), the solid-liquid mass ratio of the lees powder and the acetone aqueous solution is 1:100. Magnetic stirring is used, and after stirring for 3-5 hours, the solid and liquid are separated by centrifugation at 8000-10000 rpm. The acetone aqueous solution is made by mixing acetone and water in a volume ratio of (1-3):1. Vacuum rotary evaporation is used for concentration, and the evaporation temperature is 50℃.

[0016] According to the above scheme, in step (4), the hydrothermal reaction conditions are 160-200℃ for 6-8 hours; dialysis is performed using a 1000Da molecular weight dialysis membrane for 24-48 hours.

[0017] According to the above scheme, in step (5), the hydrothermal reaction conditions are 220-250℃ for 2-6 hours; the concentration of cellulose carbohydrates is 40g / L; and vacuum freeze drying is used for 24-36 hours.

[0018] According to the above scheme, in step (6), the mass ratio of hydrothermal carbon balls, melamine, cobalt acetate hexahydrate and potassium bicarbonate is 1:0.5:3:6; the pyrolysis temperature is 500-800℃, the pyrolysis time is 1-2h; and the temperature is increased to the pyrolysis temperature at a heating rate of 5℃ / min.

[0019] This invention also claims protection for the flower-shaped biochar ball catalyst and lignin-based carbon dot solution prepared by the above method using waste distiller's grains at multiple scales.

[0020] The above-described method describes the application of the flower-shaped biochar sphere catalyst in the removal of organic pollutants from water. The application method involves simultaneously adding the flower-shaped biochar sphere catalyst and persulfate to the polluted water, followed by a constant-temperature, oscillating reaction in a water bath for a period of time, thereby achieving the degradation and removal of organic pollutants from the water. This invention primarily utilizes the flower-shaped biochar sphere catalyst to activate persulfate, generating highly oxidizing reactive oxygen species (·OH, SO4·). - O2 - , 1 O2) can degrade organic pollutants. Through the synergistic effect of strong oxidizing active oxygen components and surface electron transfer, it can degrade most pollutants, including organic pollutants such as tetracycline, sulfadiazine, sulfamethoxazole, ciprofloxacin and enrofloxacin.

[0021] The lignin-based carbon dots prepared by the above method were used to monitor Fe in water. 3+ Applications related to concentration. The application method is as follows: based on the fluorescence intensity of carbon dots with increasing Fe... 3+ The concentration increases and decreases with a linear correlation, which can be used to monitor small amounts of Fe with a certain concentration. 3+ The Fe in the water was obtained by adding a lignin-based carbon dot solution to the water and measuring the change in fluorescence intensity detected by a fluorescence spectrophotometer. 3+ Concentration. Generally, the Fe concentration in the water body to be monitored... 3+ Within the concentration range of 10-150 μM, the fluorescence intensity of carbon dots increased with increasing Fe content. 3+ The concentration decreased with increasing concentration and showed a good linear correlation.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] First, this invention makes high-value use of waste distiller's grains, transforming them at multiple scales into flower-shaped biochar ball catalysts and carbon dot solutions for water pollution treatment. This not only alleviates the environmental pollution caused by distiller's grains but also increases the utilization rate of distiller's grains waste, while promoting the efficient treatment of complex water pollution, and has broad practical application prospects.

[0024] Secondly, the flower-shaped biochar sphere catalyst prepared in this invention has a high specific surface area and abundant catalytic active sites, enabling efficient activation and rapid degradation of organic pollutants in water by persulfate; the prepared lignin-based carbon dots exhibit good fluorescence stability and fluorescence sensing performance, enabling efficient and targeted detection of Fe in polluted water. 3+ The concentration.

[0025] Furthermore, the process technology of using the flower-shaped biochar sphere catalyst prepared in this invention in conjunction with persulfate solves many problems of traditional catalysts, such as poor stability, difficulty in recovery, high energy consumption, and high cost. At the same time, the flower-shaped biochar sphere catalyst, based on its richer active sites and accelerated metal ion redox cycle, further enhances its activation effect. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] Figure 1 This is a scanning electron microscope (SEM) image of the flower-shaped biochar ball catalyst prepared in Example 1.

[0028] Figure 2 This is an X-ray photoelectron spectroscopy (XPS) analysis of the flower-shaped biochar ball catalyst prepared in Example 1.

[0029] Figure 3 This is a time-degradation efficiency graph showing the degradation of tetracycline wastewater by the flower-shaped biochar ball catalyst prepared in Example 1 under different pH conditions.

[0030] Figure 4 This is a cyclic experiment diagram of the degradation of tetracycline wastewater by the flower-shaped biochar ball catalyst prepared in Example 1.

[0031] Figure 5 The fluorescence spectra of the lignin-based carbon dots prepared in Example 1 at different excitation wavelengths are shown.

[0032] Figure 6 The lignin-based carbon dots prepared in Example 1 are in different Fe... 3+ Fluorescence spectrum under high concentration conditions. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0034] All materials and instruments used in the following examples are commercially available. Unless otherwise specified, the data obtained in the following examples are the average values ​​of three or more repeated experiments.

[0035] Example 1

[0036] A method for preparing flower-shaped biochar balls and lignin-based carbon dots at multiple scales using waste distiller's grains specifically includes the following steps:

[0037] (1) Aluminum chloride hexahydrate and glycerol were mixed at a molar ratio of 1:8 and stirred magnetically in an oil bath at 80°C for 1 hour to obtain a light yellow, transparent, viscous eutectic solvent.

[0038] (2) Soak, wash, dry and crush the waste lees to obtain lees powder;

[0039] (3) Mix the lees powder in step (2) and the eutectic solvent prepared in step (1) at a solid-liquid ratio of 1:8, stir at a constant temperature of 110°C in an oil bath for 5 hours to obtain a brownish-black mixture A.

[0040] (4) Pour the mixture A into an acetone aqueous solution (the volume ratio of acetone to water is 7:3), the solid-liquid mass ratio of the distiller's grains powder and the acetone aqueous solution is 1:100, stir magnetically for 3 hours, and centrifuge at 10,000 rpm to obtain a mixture B of cellulose residue and lignin-eutectic solvent.

[0041] (5) Pour the mixture B into a round-bottom flask and use a rotary evaporator to evaporate the acetone completely to obtain a concentrated lignin-eutectic solvent mixture. Then pour it into a polytetrafluoroethylene reactor and react at 180°C for 6 hours to obtain a brown liquid.

[0042] (6) Remove large particles by filtration of the brown liquid in step (5), place the filtrate in a 1000 Da dialysis bag, dialyze in ultrapure water for 48 h, and then filter with a 0.22 μm filter to obtain lignin-based carbon dot solution.

[0043] (7) The cellulose residue in step (4) is washed with deionized water and then freeze-dried to obtain cellulose solid residue;

[0044] (8) Pour the cellulose solid residue from step (7) into deionized water at a concentration of 40 g / L, and then hydrothermally react at 220 °C for 4 h in a polytetrafluoroethylene reactor. After thorough washing and freeze-drying for 24 h, cellulose hydrothermal carbon balls are obtained.

[0045] (9) The hydrothermal carbon balls obtained in step (8) are ground and mixed with melamine, cobalt acetate hexahydrate and potassium bicarbonate in a mass ratio of 1:0.5:3:6 to obtain a brown homogeneous solid mixture.

[0046] (10) The solid mixture obtained in step (9) is transferred to a tube furnace and heated to 800°C at a heating rate of 5°C / min under nitrogen atmosphere protection. After holding at 800°C for 1 hour, it is naturally cooled to room temperature. It is then washed with 1M hydrochloric acid until neutral and dried to obtain flower-shaped biochar ball catalyst.

[0047] Figure 1 This is a scanning electron microscope (SEM) image of the flower-shaped biochar sphere catalyst prepared in Example 1. (The image is from...) Figure 1It can be seen that the prepared biochar exhibits a uniformly dispersed flower-shaped morphology.

[0048] Figure 2 This is an X-ray photoelectron spectroscopy (XPS) analysis of the flower-like biochar sphere catalyst prepared in Example 1. Figure 2 It can be seen that the metallic Co and the non-metallic N elements were successfully incorporated into the biochar matrix.

[0049] Figure 5 These are fluorescence spectra of the lignin-based carbon dots prepared in Example 1 at different excitation wavelengths. Figure 5 It can be seen that the lignin-based carbon dots prepared by this invention have significant fluorescence characteristics under ultraviolet excitation wavelengths of 340-490 nm; and emit relatively stable green fluorescence at 445 nm under excitation wavelength of 360 nm.

[0050] Example 2

[0051] The removal performance of the flower-shaped biochar sphere catalyst prepared in this invention on tetracycline in water was investigated. The specific process is as follows: 1 mM potassium persulfate and 75 mg / L of the catalyst prepared in this example were added to 30 mg / L tetracycline wastewater. The solution was kept at a constant temperature and shaken in a water bath at room temperature. 2.5 ml of tetracycline solution was taken at 1, 3, 5, 8, and 10 min, and the characteristic peak value of tetracycline in the solution was measured using a UV-Vis spectrophotometer to calculate the degradation efficiency. Simultaneously, the flower-shaped biochar sphere catalyst was subjected to four cycles using the same application method to investigate its stability.

[0052] The degradation reaction ended in 10 minutes, and the flower-shaped biochar ball catalyst could achieve a tetracycline removal rate of 93.00%. Figure 4 This is a cyclic experiment diagram of the degradation of tetracycline wastewater by the flower-shaped biochar ball catalyst prepared in this invention. Figure 4 It can be seen that the flower-shaped biochar ball catalyst has a good degradation effect on tetracycline after being recycled four times.

[0053] Example 3

[0054] The removal performance of the flower-shaped biochar ball catalyst prepared in this invention on tetracycline in water under different pH conditions was investigated. The specific process is as follows: The pH value of 30 mg / L tetracycline wastewater was adjusted to 3, 5, 7, 9, and 11 using 1M hydrochloric acid or sodium hydroxide. Then, 1 mM potassium persulfate and 75 mg / L flower-shaped biochar ball catalyst were added. The mixture was kept at a constant temperature and shaken in a water bath at room temperature. 2.5 ml of tetracycline solution was taken at 1, 3, 5, 8, and 10 min. The characteristic peak value of tetracycline in the solution was measured using a UV-Vis spectrophotometer, and the degradation efficiency was calculated.

[0055] The time-degradation efficiency relationship of the flower-shaped biochar ball catalyst for degrading tetracycline wastewater under different pH conditions was obtained according to Example 3. (See...) Figure 3 Within 10 minutes of reaction, the catalyst prepared in this invention exhibits high removal efficiency of tetracycline over a wide pH range.

[0056] Example 4

[0057] The application of the flower-shaped biochar ball catalyst prepared in this invention in the degradation of other antibiotic wastewater was investigated. The specific process is as follows: 1 mM potassium persulfate and 75 mg / L of the catalyst prepared in this example were added to a 10 mg / L solution of sulfadiazine, sulfamethoxazole, enrofloxacin, and ciprofloxacin. The solution was kept at a constant temperature in a water bath at room temperature and shaken. 1 ml of antibiotic reaction solution was taken at 1, 3, 5, 8, and 10 min. The characteristic peak area of ​​the antibiotic pollutants in the solution was measured by high performance liquid chromatography, and the degradation efficiency was calculated.

[0058] After a 10-minute degradation reaction, 92.96% of sulfadiazine, 93.80% of sulfamethoxazole, 97.61% of enrofloxacin, and 100% of ciprofloxacin were removed.

[0059] Example 5

[0060] This invention examines the preparation of lignin-based carbon dot solutions for the detection of Fe in aqueous solutions. 3+ The concentration of Fe was determined through the following process: 2 mL of lignin-based carbon dot solution was mixed with 3 mL of ferric chloride solution and shaken well to obtain a mixed solution; the Fe concentration in this mixed solution was... 3+ The concentration of the mixture was 10-1200 μM. After the mixed solution was allowed to stand for 10 min, the fluorescence emission spectra were measured sequentially at an excitation wavelength of 360 nm, and the characteristic peaks were recorded.

[0061] According to Example 3, lignin-based carbon dots were obtained in different Fe... 3+ Fluorescence spectra at various concentrations (10-1200 μM). For example... Figure 6 As shown, Fe 3+ The lignin-based carbon dots prepared in this invention exhibit good fluorescence quenching effects, and the fluorescence intensity of the lignin-based carbon dots increases with the amount of Fe. 3+ The concentration decreased with increasing concentration, and the correlation was linear (R0). 2 =0.96). Given the influence of Fe... 3+ With its excellent fluorescence sensing performance, the lignin-based carbon dots prepared in this invention have promising applications in environmental monitoring and sensing analysis.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing flower-shaped biochar balls and lignin-based carbon dots from waste distiller's grains at multiple scales, characterized in that, It comprises the following steps: (1) uniformly mix and heat aluminum chloride hexahydrate and glycerol to prepare a eutectic solvent; the molar ratio of aluminum chloride hexahydrate to glycerol is 1:6-10; (2) add distiller's grains powder to the eutectic solvent to separate and pretreat lignin, to obtain a mixed solution A of distiller's grains cellulose carbohydrate, lignin and eutectic solvent; the solid-liquid mass ratio of the distiller's grains powder to the eutectic solvent is 1:12-18; (3) pour the mixed solution A of distiller's grains cellulose carbohydrate, lignin and eutectic solvent obtained in step (2) into an aqueous acetone solution, stir and then centrifuge, evaporate and concentrate the remaining solution after centrifugation to obtain a concentrated lignin-eutectic solvent mixed solution; (4) perform hydrothermal reaction on the concentrated lignin-eutectic solvent mixed solution obtained in step (3), and perform dialysis and filtration to obtain lignin-based carbon dots; the hydrothermal reaction is performed at 160-200℃ for 6-8h; (5) perform hydrothermal reaction on the cellulose carbohydrate obtained in step (3), and perform washing and drying to obtain cellulose hydrothermal carbon spheres; the hydrothermal reaction is performed at 220-250℃ for 2-6h; (6) uniformly mix and grind the cellulose hydrothermal carbon spheres obtained in step (5), melamine, cobalt acetate hexahydrate and potassium bicarbonate, and pyrolyze them under a nitrogen atmosphere to obtain flower-shaped biochar spheres; the mass ratio of the cellulose hydrothermal carbon spheres, melamine, cobalt acetate hexahydrate and potassium bicarbonate is 1:0.5:3:6; the pyrolysis temperature is 500-800℃, and the pyrolysis time is 1-2h.

2. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (1), the heating temperature is 80℃, oil bath constant temperature magnetic stirring is adopted, and stirring is performed for 1-2h.

3. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (2), when separating and pretreating lignin, 80-130℃ constant temperature oil bath magnetic stirring is adopted, and stirring is performed for 1-9h.

4. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (3), the solid-liquid mass ratio of the distiller's grains powder to the aqueous acetone solution is 1:100, magnetic stirring is adopted, stirring is performed for 3-5h, and then 8000-10000rpm centrifugal separation is performed; the aqueous acetone solution is prepared by mixing acetone and water at a volume ratio of (1-3):1; vacuum rotary evaporation is adopted, and the evaporation temperature is 50℃.

5. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (4), dialysis is performed for 24-48h using a 1000Da molecular weight dialysis membrane.

6. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (5), the concentration of the cellulose carbohydrate is 40g / L; vacuum freeze drying is adopted, and the drying time is 24-36h.

7. The method of claim 1, wherein the method of preparing flower-like biochar spheres and lignin-based carbon dots from spent grain comprises: In step (6), the temperature is raised to the pyrolysis temperature at a rate of 5℃ / min.

8. Flower-shaped biochar spheres and lignin-based carbon dots prepared by the method of any one of claims 1-7.

9. Use of the flower-like biochar spheres according to claim 8 for the removal of organic pollutants from water bodies, characterized in that, The application method is as follows: the flower-shaped biochar spheres and persulfate are simultaneously added to an organic pollutant water body to achieve degradation and removal of organic pollutants in the water body; the dosing concentrations of the flower-shaped biochar spheres and persulfate in the organic pollutant water body are 0.075-0.15g / L and 0.5-2mM respectively; the mass ratio of the flower-shaped biochar spheres to persulfate is (1-1.2):

1.

10. The lignin-based carbon dots of claim 8 for use in monitoring Fe 3+ concentration in water bodies, characterized in that, The application method is: according to the fact that the fluorescence intensity of the lignin-based carbon dots decreases with the increase of the Fe 3+ Concentration and shows linear correlation, the water body to be monitored Fe 3+ Concentration is added to the solution of the lignin-based carbon dots, according to the change of the fluorescence intensity, the Fe 3+ Concentration in the water body is obtained.

Images