An iron-modified algal-based biochar-microalgae hybrid system, its preparation method, and its application.

Abstract

This invention discloses an iron-modified algal-based biochar-microalgae hybrid system, its preparation method, and its application, belonging to the field of water pollution control and treatment technology. The hybrid system comprises iron-modified algal-based biochar and microalgae culture. The preparation method of the iron-modified algal-based biochar includes the following steps: mixing and grinding microalgae powder and an iron source to obtain a precursor mixture, followed by pyrolysis and cooling to obtain the iron-modified algal-based biochar. This hybrid system can simultaneously and efficiently remove antibiotics (sulfamethoxazole) and heavy metals (Cr(VI)) from wastewater, with removal rates reaching 100% and 99.88%, respectively. It possesses multiple synergistic mechanisms including adsorption, reduction, biodegradation, and accumulation, making it suitable for the efficient and sustainable remediation of water bodies polluted by antibiotics and heavy metals.

Description

Technical Field

[0001] This invention belongs to the field of water pollution control and treatment technology, and particularly relates to an iron-modified algal-based biochar-microalgae hybrid system, its preparation method, and its application. Background Technology

[0002] With the continuous development of pharmaceutical, aquaculture, and industrial activities, the combined pollution caused by antibiotics and heavy metals has become an increasingly serious water environment problem. Antibiotics such as sulfamethoxazole (SMX) are difficult to degrade naturally in the environment and easily induce drug resistance in microorganisms; while heavy metal ions such as Cr(VI) are highly toxic, easily migrate, and bioaccumulate, posing a serious threat to ecosystems and human health. In actual water bodies, antibiotics and heavy metals often coexist, and their combined effects often make it difficult for single treatment technologies to achieve efficient simultaneous removal.

[0003] Currently, the main treatment methods for this type of complex pollution include physical adsorption, chemical reduction, and biodegradation. Traditional adsorption materials such as activated carbon and clay minerals can adsorb some organic matter or metal ions, but they suffer from limited capacity, poor selectivity, and difficulty in regeneration, and are not effective at removing low concentrations of antibiotics. Chemical reduction methods are relatively efficient at treating Cr(VI), but may introduce secondary chemical pollution and have limited ability to degrade antibiotics. Biological methods such as microalgae have certain advantages in treating low concentrations of pollutants, as they can transform some antibiotics and heavy metals through biodegradation and accumulation; however, their treatment efficiency is low, the cycle is long, and they are easily inhibited under high concentrations of pollutants, making it difficult to meet practical engineering needs.

[0004] Therefore, developing a highly efficient, economical, and environmentally friendly composite pollution control technology to achieve the synergistic removal of antibiotics and heavy metals from water bodies has become an urgent need in the field of water pollution control. Combining the strong adsorption and catalytic properties of modified biochar with the biotransformation capabilities of microalgae to construct a hybrid purification system with complementary functions holds promise for providing a new technological path to solving the aforementioned challenges. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes an iron-modified algal-based biochar-microalgae hybrid system, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing an iron-modified algal-based biochar-microalgae hybrid system includes the following steps:

[0008] Iron-modified algal-based biochar was mixed with microalgae culture and cultured to form an iron-modified algal-based biochar-microalgae hybrid system.

[0009] The concentration of the iron-modified algae-based biochar is 0.5~5 g / L; preferably 0.5 g / L, 1 g / L, or 5 g / L.

[0010] The preparation method of the iron-modified algal-based biochar includes the following steps:

[0011] Microalgae powder and iron source are mixed and ground to obtain a precursor mixture, which is then pyrolyzed and cooled to obtain the iron-modified algae-based biochar.

[0012] Optionally, the microalgae powder is Chlorella powder, which needs to be dried before use;

[0013] The iron source is ferric chloride hexahydrate (FeCl3·6H2O).

[0014] Furthermore, the drying conditions are as follows: drying at 60-70℃ for 10-24 hours.

[0015] Optionally, the mass ratio of the microalgae powder to the iron source is (1:2) to (2:1).

[0016] Furthermore, the mass ratio of the microalgae powder to the iron source is 1:1.

[0017] Optionally, the pyrolysis conditions are as follows: under inert conditions, heating to 300-750°C at a heating rate of 5-15°C / min, and maintaining at this temperature for 90-180 minutes.

[0018] Furthermore, the pyrolysis conditions are as follows: under inert conditions, the temperature is increased to 700°C at a heating rate of 10°C / min, and held at this temperature for 120 minutes.

[0019] Furthermore, the inert condition is a nitrogen atmosphere with an air flow rate of 1-1.5 L / min.

[0020] Optionally, the microalgae culture preparation process is as follows: Chlorella is inoculated into BG11 medium, and the initial concentration is adjusted to OD. 680 ≈ 0.2, to obtain a uniform microalgae suspension, which is the microalgae culture.

[0021] Optionally, the cultivation conditions are: temperature 25±1℃, light intensity 60 μmol / m². 2 / s, light-dark cycle is 12h:12h, shaker speed is 150 rpm.

[0022] This invention discloses an iron-modified algal-based biochar-microalgae hybrid system, which is prepared by the above-described preparation method.

[0023] This invention also discloses the application of the above-mentioned iron-modified algal-based biochar-microalgae hybrid system in purifying antibiotic-heavy metal complex pollution in water bodies.

[0024] Optionally, the antibiotic is sulfamethoxazole; the heavy metal is chromium.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] (1) The present invention achieves efficient and simultaneous removal of antibiotic SMX and hexavalent chromium Cr(VI) through a synergistic purification system constructed by iron-modified algal-based biochar and microalgae, with removal rates of 100% and 99.88% respectively. The overall treatment performance is significantly better than that of single biological or adsorption methods.

[0027] (2) The iron-modified algal-based biochar-microalgae hybrid system constructed in this invention has multiple complementary pollutant removal mechanisms: iron-modified algal-based biochar removes pollutants through adsorption, π-π interactions, electrostatic attraction, and Fe... 2+ The reduction process effectively enriches and transforms pollutants; microalgae, through biodegradation, bioaccumulation and biotransformation, decompose antibiotics into low-toxicity intermediates and promote the stabilization and solidification of heavy metals. The synergistic effect of the two significantly improves the purification efficiency and stability of the system.

[0028] (3) The iron-modified algae-based biochar-microalgae hybrid system constructed in this invention uses algae biomass as raw material to prepare biochar, realizing the recycling of resources; at the same time, microalgae biomass can be further converted into high value-added products, which is in line with the concept of green circular economy and has both environmental and economic benefits.

[0029] (4) The preparation method of the present invention is simple to operate and has low operating cost. It is suitable for in-situ remediation and deep end-of-pipe treatment of various water bodies and has good prospects for promotion and application. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a flowchart illustrating the preparation process of iron-modified algal-based biochar in Example 1 of the present invention.

[0032] Figure 2 The adsorption-desorption isotherm curve of the iron-modified algal-based biochar prepared in Example 1 of this invention;

[0033] Figure 3 The pore size distribution curve of the iron-modified algal-based biochar prepared in Example 1 of this invention;

[0034] Figure 4 To simulate the concentration change curve of the antibiotic sulfamethoxazole (SMX) in wastewater over time, (a) is a comparison chart of the sulfamethoxazole (SMX) content changes within 60 minutes after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid systems; (b) is a comparison chart of the sulfamethoxazole (SMX) content changes within 60 minutes after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems; (c) is a comparison chart of the sulfamethoxazole (SMX) content changes within 48 hours after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid systems; and (d) is a comparison chart of the sulfamethoxazole (SMX) content changes within 48 hours after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems.

[0035] Figure 5 The following are bar charts illustrating the heavy metal removal rates in simulated wastewater: (a) is a comparison of Cr(VI) removal rates after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and the M-0.5BC hybrid system over 48 hours; (b) is a comparison of Cr(VI) removal rates after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems over 48 hours; (c) is a comparison of Cr(VI) content changes after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and the M-0.5BC hybrid system over 48 hours; and (d) is an enlarged view of the 0-2.5 μg / L Cr(VI) content in (c).

[0036] Figure 6 A bar chart simulating nitrogen and phosphorus removal rates in wastewater; (a) NO3 treated by the microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid system within 48 hours. - (a) Comparison of NO3 removal rates; (b) NO3 removal rates after treatment by the hybrid systems of Chlorella (M), M-0.5BC, M-1.0BC and M-5.0BC within 48 hours. - -N removal rate comparison chart; (c) shows PO4 treated by the microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid system within 48 hours. 3- -P removal rate comparison chart; (d) shows PO4 removed within 48 hours by the hybrid systems of Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC. 3- -P removal rate comparison chart;

[0037] Figure 7To simulate the toxicity heatmap of the antibiotic sulfamethoxazole (SMX) in wastewater and the intermediates obtained during the treatment process;

[0038] Figure 8 The bar chart shows the SMX removal rate of the modified biochar-microalgae hybrid systems prepared using Comparative Examples 1-5. Detailed Implementation

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0042] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0043] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0044] The purpose of this invention is to provide a purification scheme for an iron-modified algal-based biochar-microalgae hybrid system targeting antibiotic-heavy metal complex pollution in water bodies. By constructing a highly efficient microalgae-biochar synergistic system, this invention solves the problems of low removal efficiency, high cost, and high risk of secondary pollution in existing technologies for complex pollutants, achieving simultaneous and efficient removal of antibiotics and heavy metals from water bodies, while promoting resource recycling and sustainable environmental development.

[0045] This invention discloses a method for preparing iron-modified algal-based biochar through modification with ferric chloride hexahydrate (FeCl3·6H2O) and high-temperature pyrolysis. The preparation steps are as follows:

[0046] Chlorella powder and ferric chloride hexahydrate (FeCl3·6H2O) were mixed and then ground to obtain a precursor mixture;

[0047] Iron-modified algae-based biochar was obtained by pyrolyzing the precursor mixture under low-oxygen conditions.

[0048] In some alternative embodiments, the Chlorella powder is dried before mixing.

[0049] Furthermore, the drying process involves treating the product at 60°C for 24 hours.

[0050] In some alternative embodiments, the content of ferric chloride hexahydrate (FeCl3·6H2O) is 50% of the dry weight of the precursor mixture.

[0051] In some alternative embodiments, grinding is done manually for 15 minutes; wherein the mortar and pestle used for grinding are made of ceramic.

[0052] In some alternative embodiments, the low-oxygen condition is an inert atmosphere or a vacuum condition.

[0053] Furthermore, the inert atmosphere is a nitrogen atmosphere.

[0054] In some alternative embodiments, the pyrolysis temperature is 700°C, the heating rate is 10°C / min, and the time is 120 min.

[0055] This invention provides an iron-modified algal-based biochar prepared by the above method.

[0056] This invention also provides a method for preparing an iron-modified algal-based biochar-microalgae hybrid system, the steps of which are as follows:

[0057] The above-mentioned iron-modified algal-based biochar was mixed with microalgae culture to form an iron-modified algal-based biochar-microalgae hybrid system.

[0058] In some optional embodiments, the concentration of iron-modified algal-based biochar is 0.5~5 g / L, that is, the amount of iron-modified algal-based biochar added in 1 liter of iron-modified algal-based biochar-microalgae hybrid system is 0.5-5 g.

[0059] In some alternative embodiments, the microalgae culture is a suspension of Chlorella vulgaris in BG11 medium, with the initial inoculum concentration controlled at OD. 680 ≈ 0.2.

[0060] In some optional embodiments, the preparation method of the iron-modified algal-based biochar-microalgae hybrid system specifically includes the following steps:

[0061] Iron-modified algal-based biochar was added to the microalgae culture and manually mixed for 30 seconds to form a mixture.

[0062] The mixture was cultured under fixed conditions on a light-controlled, temperature-controlled shaker.

[0063] In some optional embodiments, the fixed conditions are a temperature of 25±1℃ and a light intensity of 60 μmol / m². 2 / s, light-dark cycle is 12h:12h, shaker speed is 150 rpm.

[0064] This invention discloses an iron-modified algal-based biochar-microalgae hybrid system prepared by the above-described method.

[0065] This invention also discloses the application of the above-mentioned iron-modified algal-based biochar-microalgae hybrid system in purifying antibiotic-heavy metal complex pollution in water bodies.

[0066] In some alternative embodiments, the antibiotic is sulfamethoxazole (SMX) at an initial concentration of 0.2 mg / L; the heavy metal is hexavalent chromium (Cr(VI)) at an initial concentration of 0.5 mg / L.

[0067] Furthermore, this invention utilizes ECOSAR software to assess the environmental toxicity of antibiotic degradation products.

[0068] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0069] All raw materials used in this invention were purchased commercially. The Chlorella used in the following examples was provided by the Wuhan Institute of Hydrobiology, and the algae powder used was provided by Waterworld Biotechnology (Zhenjiang) Co., Ltd.

[0070] The technical solution of the present invention will be further illustrated by the following embodiments.

[0071] Example 1

[0072] like Figure 1 As shown, a method for preparing iron-modified algal-based biochar includes the following steps:

[0073] S1. Dry the algal biomass (Chlorella vulgaris algal powder) at 60℃ for 24 hours and set aside for later use.

[0074] S2. The dried algal biomass and the modifier ferric chloride hexahydrate (FeCl3·6H2O) are mixed at a mass ratio of 1:1, and then manually ground for 15 minutes to make it fully and evenly mixed to obtain the precursor mixture.

[0075] S3. Place the precursor mixture in a horizontal tube furnace and pyrolyze it under a nitrogen atmosphere (flow rate of 1 L / min). The pyrolysis program is set as follows: heat to 700°C at a heating rate of 10°C / min and hold at that temperature for 120 minutes.

[0076] S4. After pyrolysis, allow the product to cool naturally to room temperature in the furnace, remove it, pass it through a 200-mesh sieve, seal and store it. The final product obtained is iron-modified algae-based biochar, denoted as BC.

[0077] Figure 2 The figure shows the adsorption-desorption isotherm of the iron-modified algae-based biochar prepared in Example 1 of this invention. As can be seen from the figure, the adsorption-desorption isotherm of the iron-modified algae-based biochar belongs to the type IV isotherm, and there is a significant hysteresis loop between the adsorption curve and the desorption curve, which is a typical characteristic of mesoporous materials. At the same time, when the relative pressure (P / P0) approaches 1.0, the adsorption amount increases sharply, indicating that the material also has a certain macroporous structure.

[0078] Figure 3 The figure shows the pore size distribution curve of the iron-modified algal-based biochar prepared in Example 1 of the present invention. As can be seen from the figure, the pore size distribution of the iron-modified algal-based biochar is relatively concentrated. The peak value of its pore volume corresponds to the pore size in the mesoporous range (2~50nm), indicating that the pore size of the iron-modified algal-based biochar is mainly mesoporous and has a relatively concentrated pore size distribution.

[0079] Example 2

[0080] A method for preparing iron-modified algal-based biochar includes the following steps:

[0081] S1, the same as S1 in Example 1;

[0082] S2. The dried algal biomass and the modifier ferric chloride hexahydrate (FeCl3·6H2O) were mixed at a mass ratio of 1:1.5, and then manually ground for 20 minutes to make it fully and evenly mixed to obtain the precursor mixture.

[0083] S3. The precursor mixture was placed in a horizontal tube furnace and pyrolyzed under a nitrogen atmosphere (flow rate of 1.2 L / min). The pyrolysis program was set as follows: heating to 500°C at a heating rate of 5°C / min and holding at that temperature for 90 minutes;

[0084] S4, the same as S4 in Example 1.

[0085] Example 3

[0086] A method for preparing iron-modified algal-based biochar includes the following steps:

[0087] S1, the same as S1 in Example 1;

[0088] S2. The dried algal biomass and the modifier ferric chloride hexahydrate (FeCl3·6H2O) were mixed at a mass ratio of 1.5:1, and then manually ground for 30 minutes to make it fully and evenly mixed to obtain the precursor mixture.

[0089] S3. The precursor mixture is placed in a horizontal tube furnace and pyrolyzed under a nitrogen atmosphere (flow rate of 1 L / min). The pyrolysis program is set as follows: heat to 300°C at a heating rate of 8°C / min and hold at that temperature for 150 minutes;

[0090] S4, the same as S4 in Example 1.

[0091] Example 4

[0092] A method for preparing iron-modified algal-based biochar includes the following steps:

[0093] S1. Dry the algal biomass (Spirulina algal powder) at 70℃ for 10 hours and set aside for later use;

[0094] S2, the same as S2 in Example 1;

[0095] S3. The precursor mixture is placed in a horizontal tube furnace and pyrolyzed under a nitrogen atmosphere (flow rate of 1.5 L / min). The pyrolysis program is set as follows: heat to 750°C at a heating rate of 15°C / min and hold at that temperature for 100 minutes;

[0096] S4, the same as S4 in Example 1.

[0097] Example 5

[0098] A method for preparing iron-modified algal-based biochar includes the following steps:

[0099] S1, the same as S1 in Example 1;

[0100] S2. The dried algal biomass and the modifier ferric chloride hexahydrate (FeCl3·6H2O) were mixed at a mass ratio of 1:2, and then manually ground for 15 minutes to make it fully and evenly mixed to obtain the precursor mixture.

[0101] S3. The precursor mixture is placed in a horizontal tube furnace and pyrolyzed under a nitrogen atmosphere (flow rate of 1 L / min). The pyrolysis program is set as follows: heat to 650°C at a heating rate of 10°C / min and hold at that temperature for 180 minutes;

[0102] S4, the same as S4 in Example 1.

[0103] Example 6

[0104] A method for preparing iron-modified algal-based biochar includes the following steps:

[0105] S1, the same as S1 in Example 1;

[0106] S2. The dried algal biomass and the modifier ferric chloride hexahydrate (FeCl3·6H2O) were mixed at a mass ratio of 2:1, and then manually ground for 20 minutes to make it fully and evenly mixed to obtain the precursor mixture.

[0107] S3. The precursor mixture is placed in a horizontal tube furnace and pyrolyzed under a nitrogen atmosphere (flow rate of 1 L / min). The pyrolysis program is set as follows: heat to 550°C at a heating rate of 12°C / min and hold at that temperature for 120 minutes;

[0108] S4, the same as S4 in Example 1.

[0109] Comparative Example 1

[0110] The only difference from Example 1 is that the pyrolysis temperature in step S3 is replaced with 500°C, while the other preparation conditions are the same as in Example 1, denoted as BCFe-500.

[0111] Comparative Example 2

[0112] The only difference from Example 1 is that the pyrolysis temperature in step S3 is replaced with 300°C, while the other preparation conditions are the same as in Example 1, denoted as BCFe-300.

[0113] Comparative Example 3

[0114] The only difference from Example 1 is that the modifier ferric chloride hexahydrate was replaced with KOH, and the pyrolysis temperatures were 300, 500, and 700°C, respectively. All other preparation conditions were the same as in Example 1. The final products were designated BCK-300, BCK-500, and BCK-700, respectively.

[0115] Comparative Example 4

[0116] The only difference from Example 1 is that the modifier ferric chloride hexahydrate was replaced with NaH2PO4, and the pyrolysis temperatures were 300, 500, and 700°C, respectively. All other preparation conditions were the same as in Example 1. The final products were designated BCP-300, BCP-500, and BCP-700, respectively.

[0117] Comparative Example 5

[0118] The only difference from Example 1 is that the modifier ferric chloride hexahydrate was replaced with CaCl2, and the pyrolysis temperatures were 300, 500, and 700°C, respectively. All other preparation conditions were the same as in Example 1. The final products were designated BCCa-300, BCCa-500, and BCCa-700, respectively.

[0119] Application Example 1

[0120] The iron-modified algal biochar (BC) prepared in Example 1 was used to construct an iron-modified algal biochar-microalgae hybrid system with different iron-modified algal biochar addition concentrations. The specific preparation process is as follows:

[0121] (1) Preparation of microalgae culture: Chlorella was inoculated into 300 ml of BG11 medium and the initial concentration was adjusted to OD. 680 ≈ 0.2, to obtain a uniform microalgae suspension;

[0122] (2) Adding iron-modified algal biochar: Adding iron-modified algal biochar to the above microalgae culture at different concentrations;

[0123] (3) Mix thoroughly by hand for 30 seconds to form a uniform BC-microalgae mixture system;

[0124] (4) Incubation: The mixed system was placed in a light-controlled, temperature-controlled shaker and incubated under the following conditions: temperature 25±1℃, light intensity 60 μmol / m 2 / s, light-dark cycle is 12h:12h, shaker speed is 150 rpm.

[0125] In this process, by changing the amount of iron-modified algal biochar added in step (2), iron-modified algal biochar-microalgae hybrid systems with different iron-modified algal biochar contents were prepared. The specific amounts added were 0.5 g / L, 1 g / L, and 5 g / L (representing the number of grams of iron-modified algal biochar contained in 1 liter of iron-modified algal biochar-microalgae hybrid system). The corresponding iron-modified algal biochar-microalgae hybrid systems were M-0.5BC, M-1.0BC, and M-5.0BC, respectively.

[0126] Application Comparative Examples 1-5

[0127] Eleven types of modified biochar from Comparative Examples 1-5 were used to construct biochar-microalgae hybrid systems with Chlorella vulgaris at a modified biochar dosage of 0.5 g / L. The specific preparation process was the same as in Application Example 1.

[0128] 300 ml of modified biochar-microalgae hybrid systems (BCFe-500, BCFe-300, BCK-300, BCK-500, BCK-700, BCP-300, BCP-500, BCP-700, BCCa-300, BCCa-500, BCCa-700) prepared using Comparative Examples 1-5 were respectively added to sulfamethoxazole (SMX) at an initial concentration of 0.2 mg / L. The specific SMX removal effects are as follows: Figure 8 As shown.

[0129] Figure 8 The bar chart shows the SMX removal rate of the modified biochar-microalgae hybrid systems prepared in Comparative Examples 1-5. It can be seen from the figure that the highest SMX removal rate is 58.61% under the BCFe-500 addition condition, which is much lower than that of the iron-modified algae-based biochar-microalgae hybrid system in Application Example 1. This proves that the hybrid system prepared in Application Example 1 of this invention has an excellent removal effect on antibiotics (sulfamethoxazole).

[0130] Effect verification

[0131] Example 1

[0132] The removal efficacy of sulfamethoxazole and heavy metal Cr was verified in the following five systems, with each system having a volume of 300 ml, as detailed below:

[0133] Sulfamethoxazole (SMX) and Cr were added to 300 ml of the iron-modified algal-based biochar-microalgae hybrid systems (M-0.5BC, M-1.0BC, and M-5.0BC) prepared in Example 1, respectively, so that the concentration of sulfamethoxazole (SMX) in each system was 0.2 mg / L and Cr(VI) was 0.5 mg / L. After reacting for 48 hours under room temperature and natural light conditions, the concentrations of residual SMX and Cr(VI) in the water were measured.

[0134] Sulfamethoxazole (SMX) and Cr were added to 300 ml of a single microalga, Chlorella (M) (Chlorella was inoculated into BG11 medium at an initial optical density (OD680) of 0.2), so that the concentration of sulfamethoxazole (SMX) in each system was 0.2 mg / L and Cr(VI) was 0.5 mg / L. After reacting for 48 hours under room temperature and natural light conditions, the residual concentrations of SMX and Cr(VI) in the water were measured.

[0135] Sulfamethoxazole (SMX) and Cr were added to 300 ml of iron-modified algal biochar (BC) system prepared in Example 1 (the amount of iron-modified algal biochar added in BG11 medium was 0.5 g / L) so that the concentration of sulfamethoxazole (SMX) in each system was 0.2 mg / L and Cr(VI) was 0.5 mg / L. After reacting for 48 hours under room temperature and natural light conditions, the concentrations of residual SMX and Cr(VI) in the water were measured.

[0136] Figure 4 To simulate the concentration change curve of the antibiotic sulfamethoxazole (SMX) in wastewater over time, (a) is a comparison chart of the sulfamethoxazole (SMX) content changes within 60 minutes after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid systems; (b) is a comparison chart of the sulfamethoxazole (SMX) content changes within 60 minutes after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems; (c) is a comparison chart of the sulfamethoxazole (SMX) content changes within 48 hours after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid systems; and (d) is a comparison chart of the sulfamethoxazole (SMX) content changes within 48 hours after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems.

[0137] Figure 5 The following are bar charts illustrating the heavy metal removal rates in simulated wastewater: (a) is a comparison of Cr(VI) removal rates after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and the M-0.5BC hybrid system over 48 hours; (b) is a comparison of Cr(VI) removal rates after treatment with microalgae Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC hybrid systems over 48 hours; (c) is a comparison of Cr(VI) content changes after treatment with microalgae Chlorella (M), iron-modified algal biochar (BC), and the M-0.5BC hybrid system over 48 hours; and (d) is an enlarged view of the 0-2.5 μg / L Cr(VI) content in (c).

[0138] from Figures 4-5 As can be seen, under the action of this hybrid system, the removal rates of SMX and Cr(VI) reached 100% and 99.48%, respectively.

[0139] Example 2

[0140] Furthermore, to evaluate the anti-interference ability of the hybrid system in complex water bodies, 1500 mg / L of nitrate nitrogen and 40 mg / L of orthophosphate were introduced into the simulated wastewater as background interference.

[0141] Figure 6 A bar chart simulating nitrogen and phosphorus removal rates in wastewater; (a) NO3 treated by the microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid system within 48 hours. - (a) Comparison of NO3 removal rates; (b) NO3 removal rates after treatment by the hybrid systems of Chlorella (M), M-0.5BC, M-1.0BC and M-5.0BC within 48 hours. - -N removal rate comparison chart; (c) shows PO4 treated by the microalgae Chlorella (M), iron-modified algal biochar (BC), and M-0.5BC hybrid system within 48 hours. 3- -P removal rate comparison chart; (d) shows PO4 removed within 48 hours by the hybrid systems of Chlorella (M), M-0.5BC, M-1.0BC, and M-5.0BC. 3- -P removal rate comparison chart.

[0142] from Figure 6 As can be seen, the nitrogen and phosphorus removal rates of the hybrid system prepared in Application Example 1 are 86.56%-88.04% and 99.17%-99.65%, respectively, proving that the hybrid system prepared in Application Example 1 has excellent purification effect on complex polluted water bodies with multiple pollutants coexisting.

[0143] Example 3

[0144] Furthermore, to assess the environmental friendliness of this hybrid system, the toxicity of antibiotic degradation products was analyzed using ECOSAR software.

[0145] Figure 7 To simulate the toxicity heatmap of the antibiotic sulfamethoxazole (SMX) in wastewater and the intermediates obtained during the treatment process.

[0146] from Figure 7 As can be seen, SMX is degraded into low molecular weight organic acids, aldehydes, and finally inorganic ions. Its acute and chronic toxicity is significantly reduced compared to the parent SMX, proving that the hybrid system prepared in Example 1 of this invention can effectively achieve the detoxification goal while efficiently removing pollutants, and has excellent ecological safety.

[0147] In summary, the iron-modified algae-based biochar-microalgae hybrid system provided in Example 1 of this invention not only demonstrates highly efficient simultaneous removal capabilities for typical antibiotic and heavy metal composite pollution, but also maintains stable performance in complex water bodies containing natural organic matter. It is suitable for various practical scenarios such as deep purification of wastewater treatment plant effluent, treatment of polluted surface water and industrial wastewater, and provides a reliable technical option for the remediation of composite water pollution.

[0148] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of an iron-modified algal-based biochar-microalgae hybrid system in purifying antibiotic-heavy metal complex pollution in water bodies, characterized in that, The preparation method of the iron-modified algal-based biochar-microalgae hybrid system includes the following steps: Iron-modified algal-based biochar was mixed with microalgae culture and cultured to form an iron-modified algal-based biochar-microalgae hybrid system. The concentration of the iron-modified algae-based biochar is 0.5~5 g / L; The preparation method of the iron-modified algal-based biochar includes the following steps: Microalgae powder and iron source are mixed and ground to obtain a precursor mixture, which is then pyrolyzed and cooled to obtain the iron-modified algae-based biochar. The microalgae powder is Chlorella powder, which needs to be dried before use; The iron source is ferric chloride hexahydrate; The pyrolysis conditions are as follows: under inert conditions, heating to 700°C at a heating rate of 10°C / min, and maintaining at this temperature for 120 minutes; The antibiotic is sulfamethoxazole; the heavy metal is chromium.

2. The application of the iron-modified algal-based biochar-microalgae hybrid system according to claim 1 in purifying antibiotic-heavy metal complex pollution in water bodies, characterized in that, The mass ratio of the microalgae powder to the iron source is (1:2) to (2:1).

3. The application of the iron-modified algal-based biochar-microalgae hybrid system according to claim 1 in purifying antibiotic-heavy metal complex pollution in water bodies, characterized in that, The inert conditions are a nitrogen atmosphere with an air flow rate of 1-1.5 L / min.

4. The application of the iron-modified algal-based biochar-microalgae hybrid system according to claim 1 in purifying antibiotic-heavy metal complex pollution in water bodies, characterized in that, The culture conditions are: temperature 25±1℃, light intensity 60 μmol / m 2 2s, light-dark cycle 12h:12h, shaking speed 150 rpm.

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