Wetland plant biochar-derived dissolved organic matter coupled with δ-manganese dioxide water treatment agent

Abstract

The present application belongs to the field of water treatment and environmental management, and provides a wetland plant biochar derived dissolved organic matter coupled delta manganese dioxide water treatment agent, which is composed of the following raw materials in parts by weight: wetland plant biochar derived dissolved organic matter 5-8 parts, delta manganese dioxide 6-9 parts; wherein the preparation method of the wetland plant biochar derived dissolved organic matter comprises: preparing biochar from wetland plants, immersing the biochar in a solvent, extracting under mechanical vibration / stirring, and collecting the solvent to obtain the product. The present application efficiently removes sulfamethoxazole in water bodies through the dissolved organic matter (DOM) of biochar coupled with delta-MnO2, solving the problem of low removal efficiency of traditional water treatment agents.

Description

Technical Field

[0001] This invention belongs to the field of water treatment and environmental management, and relates to a wetland plant biochar-derived dissolved organic matter coupled with δ-manganese dioxide water treatment agent. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Sulfamethoxazole is a widely used sulfonamide antibiotic, extensively applied in medicine, animal husbandry, and aquaculture. However, its environmental residues are causing increasingly serious pollution problems, posing a multi-dimensional threat to water bodies, soil, and ecosystems. Therefore, removing sulfamethoxazole has become a very urgent task.

[0004] Extensive research has been conducted on the degradation of sulfamethoxazole in water, with common methods including adsorption and advanced oxidation processes. However, the cumbersome and expensive preparation of adsorbents means they cannot yet meet the demand for highly efficient removal of sulfamethoxazole from water. While traditional advanced oxidation processes are highly efficient at removing pollutants, the high cost of oxidants and the potential for secondary pollution are significant drawbacks.

[0005] One study disclosed a biochar-derived soluble organic compound and its application in treating p-nitrophenol. Another study disclosed that DOM has a promoting or inhibiting effect on the adsorption of antibiotics by biochar. However, the treatment of sulfamethoxazole in water by wetland plant biochar-derived soluble organic compound coupled with δ-MnO2 was not addressed.

[0006] Therefore, there is an urgent need to develop more efficient water treatment agents to meet the requirements for the removal of sulfamethoxazole from water. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a wetland plant biochar-derived dissolved organic matter coupled with δ-manganese dioxide water treatment agent, which efficiently removes sulfamethoxazole from water through the coupling of dissolved organic matter (DOM) from biochar with δ-MnO2.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a wetland plant biochar-derived dissolved organic matter coupled with δ-manganese dioxide water treatment agent, which is composed of the following raw materials in parts by weight: 5-8 parts of wetland plant biochar-derived dissolved organic matter and 6-9 parts of δ-manganese dioxide;

[0010] The method for preparing dissolved organic matter derived from wetland plant biochar includes: making wetland plants into biochar, impregnating the biochar in a solvent, extracting it under mechanical vibration / stirring, and collecting the solvent to obtain the final product.

[0011] This invention utilizes biochar-derived dissolved organic matter (DOM) combined with δ-MnO2 for the efficient removal of sulfamethoxazole from water. The dissolved organic matter (DOM) of biochar is rich in polyphenols, which act as electron shuttles, promoting electron transfer between δ-MnO2 and pollutants, accelerating the reaction rate, and promoting the removal of sulfamethoxazole from water. 4+ The oxidation of tetravalent manganese ions and the generation of ·OH (hydroxyl radicals) achieve highly efficient removal of sulfamethoxazole. Biochar DOM and δ-MnO2 synergistically enhance oxidation capacity. Combining the adsorption-catalysis-complexation function of biochar DOM, the dual goals of efficient pollutant degradation and heavy metal stabilization are achieved. Furthermore, biochar DOM can generate reactive oxygen species (such as... 3 DOM* (Triple-state dissolved organic matter) → 1 O2 (single-state oxygen) or ·OH promotes the generation of ROS (reactive oxygen species) and prolongs the lifetime of free radicals.

[0012] Biochar-derived dissolved organic matter bound to δ-MnO2 is applicable across a variety of pH ranges. Under acidic conditions (pH 3–5), the redox potential of δ-MnO2 and the desorption of divalent / trivalent manganese are favorable. 4+ Enhanced oxidizing capacity improves the removal efficiency of sulfamethoxazole; under alkaline conditions (pH 8-10), polyphenols in biochar can increase electron transfer efficiency and promote reactive oxygen species, such as: 1 O2 or ·OH is generated. Therefore, the combined use of biochar-derived dissolved organic matter and δ-MnO2 has different promoting effects at different pH ranges.

[0013] Beneficial effects of the present invention

[0014] (1) This invention utilizes wetland waste plant biomass to prepare water onion, which is easy to obtain and has low cost.

[0015] (2) The water treatment agent of the present invention has wide adaptability and can achieve efficient removal of sulfamethoxazole (>80%) in environments with pH of 3-9.

[0016] (3) The wetland plant biochar-derived dissolved organic matter of the present invention has multifunctional group characteristics, containing abundant carboxyl, phenolic hydroxyl, amino and other functional groups, which can combine with sulfamethoxazole through electrostatic interaction, hydrogen bonding or coordination bond to form a stable complex, thereby reducing its bioavailability.

[0017] (4) The dissolved organic matter produced by the hydrolysis of wetland plant water onion has more polyphenols, which can improve the efficiency of extracellular electron transfer, promote the generation of free radicals from dissolved organic matter and δ-MnO2, and promote the efficient removal and mineralization of antibiotics.

[0018] (5) The present invention combines DOM and δ-MnO2, which has strong oxidizing ability and has a good removal effect on various antibiotics or pollutants. Attached Figure Description

[0019] Figure 1 This is a SEM image of δ-MnO2 from the present invention;

[0020] Figure 2 The XRD pattern of δ-MnO2 of the present invention (JCPDS PDF# 80-1098);

[0021] Figure 3 The images shown are scanning electron microscope images of the biochar prepared in Example 1 of this invention. A: cage-like structure, B: tubular structure.

[0022] Figure 4 The three-dimensional fluorescence spectra of DOM prepared in Examples 1-3 of this invention are shown. A: microbial-derived humus, B: terrestrial humus, and C: tryptophan-like protein substances. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0025] This invention provides a wetland plant biochar-derived dissolved organic matter coupled with δ-manganese dioxide water treatment agent, which is composed of the following raw materials in parts by weight: 5-8 parts of wetland plant biochar-derived dissolved organic matter and 6-9 parts of δ-manganese dioxide;

[0026] The method for preparing dissolved organic matter derived from wetland plant biochar includes: making wetland plants into biochar, impregnating the biochar in a solvent, extracting it under mechanical vibration / stirring, and collecting the solvent to obtain the final product.

[0027] The composition of DOM (biochar substrate) is related to the type of biomass feedstock and the pyrolysis temperature. This invention performs three-dimensional fluorescence spectroscopy and parallel factor analysis on DOM prepared from different feedstocks (water onion, reed) and at different pyrolysis temperatures (160℃, 180℃, 200℃). Preferably, the wetland plant is water onion or reed. In winter, water onion usually withers and is discarded; this invention uses it as a raw material for biochar, which is inexpensive and readily available.

[0028] δ-MnO2 is generated in one step via a hydrothermal method. This simple preparation method can effectively improve the resource utilization rate of constructed wetlands and reduce the concentration of sulfonamides in the aquatic environment. The reagents used in this invention are environmentally friendly and will not have adverse effects on the ecosystem. It requires no other complex operations and is convenient and quick.

[0029] This invention does not impose any particular limitation on the preparation method of biochar. In some embodiments, the preparation method of biochar includes: subjecting wetland plants to a hydrothermal reaction to obtain the biochar. The entire process is carried out in a high-temperature water environment, without the need for complete drying of the raw materials, making it suitable for the treatment of wetland plants with high water content.

[0030] The temperature of the hydrothermal reaction affects the formation efficiency and yield of biochar. Therefore, this invention studies the temperature and time of the hydrothermal reaction. In some embodiments, the hydrothermal reaction is carried out at 160℃-200℃ for 12-16 hours to improve the yield of biochar.

[0031] In some embodiments, after the hydrothermal reaction, the product is collected and dried at 70°C-80°C for 10-12 hours to remove moisture from the biochar, facilitating the subsequent extraction of dissolved organic matter derived from the biochar.

[0032] The particle size of biochar affects the extraction efficiency of DOM (morphocyanate). Therefore, this invention studies the particle size of biochar. In some embodiments, the particle size of the biochar is <75 μm to utilize small-particle-size biochar.

[0033] Larger specific surface area and shorter diffusion path significantly improve DOM extractability.

[0034] The type of solvent affects the extraction efficiency and composition of DOM. Therefore, this invention has studied the types of solvents. In some embodiments, the solvent is water to extract water-soluble DOM more efficiently and obtain biochar-derived dissolved organic matter containing abundant functional groups such as carboxyl, phenolic hydroxyl, and amino groups.

[0035] The solid-liquid ratio directly affects the contact area between the solvent and the solid raw material and the extraction efficiency. Therefore, this invention studies the mass ratio of biochar to solvent. In some embodiments, the mass ratio of biochar to solvent is 1:50-80 to better improve the extraction efficiency.

[0036] Mechanical vibration can promote the contact and mixing of biochar and solvent, thereby improving extraction efficiency. Therefore, this invention has studied the rotation speed and duration of mechanical vibration. In some embodiments, the mechanical vibration conditions are: shaking at 200-300 rpm for 1-2 hours to better extract biochar-derived dissolved organic matter.

[0037] The extracted wetland plant biochar-derived dissolved organic matter inevitably contains some impurities, which can affect the subsequent water treatment effect. Therefore, in some embodiments, the preparation method of wetland plant biochar-derived dissolved organic matter also includes: filtration using a 0.45μm filter membrane to remove impurities and improve water treatment efficiency.

[0038] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0039] In the following examples, the preparation method of δ-MnO2 is as follows: 1.896 g of KMnO4 (potassium permanganate) was dissolved in 70 ml of deionized water, and then 0.338 g of MnSO4·H2O (manganese titanium dioxide sulfate) was added to the mixture, followed by swirl for 30 min. Subsequently, the mixture was transferred to a high-temperature, high-pressure reactor lined with polytetrafluoroethylene and heated at 160°C for 12 h. After the reaction was complete, the mixture was filtered and dried in an oven at 70°C for 12 h. The obtained MnO2 (manganese dioxide) was scanned using a scanning electron microscope to observe its shape. MnO2 conforming to this crystal form, such as… Figure 1 , Figure 2 As shown.

[0040] Sulfamethoxazole was detected by high-performance liquid chromatography (HPLC). The chromatographic column was an octadecyl-bonded phase (C18) reversed-phase column with a length of 250 mm and an inner diameter of 4.6 mm. The mobile phase consisted of 0.1 wt% acetic acid in water and acetonitrile. The flow rate was 1 mL / min, the injection volume was 10 μL, the column temperature was 35°C, and the isocratic gradient was 60% acetic acid in water and 40% acetonitrile.

[0041] Example 1

[0042] Remove the roots from the water onions with tap water, wash them thoroughly, and air-dry them naturally for 3 days. Dry them at 70℃ for 48 hours to remove moisture, then pulverize them using a pulverizer and pass them through a 10-mesh sieve. Take 10g of water onion stalks and mix them evenly with tap water at a mass ratio of 1:10. Place the above sample into a polytetrafluoroethylene-lined reactor, install the hydrothermal synthesis reactor, and place it in a forced-air drying oven. Perform a hydrothermal reaction at 200℃ for 12 hours, then close the oven and wait for the reactor to cool to the desired temperature before removing it. Filter the mixture, dry it in a 70℃ oven for 6 hours, and pass it through a 200-mesh sieve to ensure the biochar particle size is <75 μm, thus obtaining water onion biochar. Figure 3 As shown in Figures A and B, these are for later use. Biochar and water are mixed at a mass ratio of 1:50 and treated on a shaker at 200 rpm for 2 hours. After reaction, the mixture is filtered to obtain the dissolved organic matter derived from the biochar of water onion. The above sample is mixed with δ-MnO2 at a mass ratio of 5:6, and sulfamethoxazole standard is added to a concentration of 2500 ppb. The mixture is placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples are taken at 240 min, filtered through a 0.22 μm membrane, and stored at 4°C. Sulfamethoxazole is detected using high-performance liquid chromatography (HPLC).

[0043] In this embodiment, the surface characteristics of biochar were determined using a Micron ASAP2020 HD88 fully automated specific surface area and micropore analyzer. The specific surface area of ​​the water onion biochar was 9.197 m². 2 / g, pore volume is 0.026976 cm³ 3 / g. Elemental analysis of the obtained biochar was performed using an EA organic elemental analyzer from Elementar GmbH, Germany. The C / H ratio of the biochar was 25:3. The C / H ratio increased with increasing reaction temperature, indicating a higher degree of carbonization.

[0044] Example 2

[0045] Remove the roots from the water onions with tap water, wash them thoroughly, and air-dry them naturally for 3 days. Dry them at 70℃ for 48 hours to remove moisture, then pulverize them using a pulverizer and pass them through a 10-mesh sieve. Take 10g of water onion stalks and mix them evenly with tap water at a mass ratio of 1:10. Place the sample in a polytetrafluoroethylene-lined container, install a hydrothermal synthesis reactor, and place it in a forced-air drying oven. Perform a hydrothermal reaction at 180℃ for 12 hours, then close the oven and wait for the reactor to cool to the desired temperature before removing it. Filter the mixture, dry it in a 70℃ oven for 6 hours, and pass it through a 200-mesh sieve to ensure the biochar particle size is <75 μm, thus obtaining water onion biochar for later use. Mix the biochar with water at a mass ratio of 1:50, treat the mixture on a shaker at 200 rpm for 2 hours, and filter after the reaction to obtain the water onion biochar-derived dissolved organic matter. The above sample was mixed thoroughly with δ-MnO2 at a mass ratio of 5:6, and sulfamethoxazole standard was added to achieve a concentration of 2500 ppb. The mixture was placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples were taken at 240 min, filtered through a 0.22 μm filter membrane, and stored at 4°C. Sulfamethoxazole was detected using high-performance liquid chromatography (HPLC).

[0046] Example 3

[0047] Remove the roots from the water onions with tap water, wash them thoroughly, and air-dry them naturally for 3 days. Dry them at 70℃ for 48 hours to remove moisture, then pulverize them using a pulverizer and pass them through a 10-mesh sieve. Take 10g of water onion stalks and mix them evenly with tap water at a mass ratio of 1:10. Place the sample in a polytetrafluoroethylene-lined container, install a hydrothermal synthesis reactor, and place it in a forced-air oven. Perform a hydrothermal reaction at 160℃ for 12 hours, then close the oven and wait for the reactor to cool to the desired temperature before removing it. Filter the mixture, dry it in a 70℃ oven for 6 hours, and pass it through a 200-mesh sieve to ensure the biochar particle size is <75 μm, thus obtaining water onion biochar. Mix the biochar with water at a mass ratio of 1:50, treat the mixture on a shaker at 200 rpm for 2 hours, and filter after the reaction to obtain the water onion biochar-derived dissolved organic matter. The above sample was mixed thoroughly with δ-MnO2 at a mass ratio of 5:6, and sulfamethoxazole standard was added to achieve a concentration of 2500 ppb. The mixture was placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples were taken at 240 min, filtered through a 0.22 μm filter membrane, and stored at 4°C. Sulfamethoxazole was detected using high-performance liquid chromatography (HPLC).

[0048] Comparative Example 1:

[0049] Remove the roots from the water onions with tap water, wash them thoroughly, and air-dry them naturally for 3 days. Dry them at 70℃ for 48 hours to remove moisture, then pulverize them using a pulverizer and pass them through a 10-mesh sieve. Take 10g of water onion straw and mix it evenly with tap water at a mass ratio of 1:10. Place the sample in a polytetrafluoroethylene-lined container, install a hydrothermal synthesis reactor, and place it in a forced-air drying oven. Perform a hydrothermal reaction at 200℃ for 12 hours, then close the oven and wait for the reactor to cool to the desired temperature before removing it. Filter the mixture, dry it in a 70℃ oven for 6 hours, and pass it through a 200-mesh sieve to ensure the biochar particle size is <75 μm, thus obtaining water onion biochar for later use. Mix the biochar with water at a mass ratio of 1:50, treat it on a shaker at 200 rpm for 2 hours, and filter it after the reaction to obtain the water onion biochar-derived dissolved organic matter. The above samples were mixed with sulfamethoxazole standard to a concentration of 2500 ppb and placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples were taken at 240 min, filtered through a 0.22 μm filter membrane, and stored at 4°C. Sulfamethoxazole was detected using high-performance liquid chromatography (HPLC).

[0050] Comparative Example 2

[0051] 1.74 g of δ-MnO2 was dispersed in 40 ml of pure water, and sulfamethoxazole standard was added to achieve a concentration of 2500 ppb. The mixture was placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples were taken at 240 min, filtered through a 0.22 μm filter membrane, and stored at 4°C. Sulfamethoxazole was detected using high-performance liquid chromatography (HPLC).

[0052] Comparative Example 3

[0053] Remove the roots from the water onions with tap water, wash them thoroughly, and air-dry them naturally for 3 days. Dry them at 70℃ for 48 hours to remove moisture, then pulverize them using a pulverizer and pass them through a 10-mesh sieve. Take 10g of water onion stalks and mix them evenly with tap water at a mass ratio of 1:10. Place the sample in a polytetrafluoroethylene-lined container, install a hydrothermal synthesis reactor, and place it in a forced-air drying oven. Perform a hydrothermal reaction at 180℃ for 12 hours, then close the oven and wait for the reactor to cool to the desired temperature before removing it. Filter the mixture, dry it in a 70℃ oven for 6 hours, and pass it through a 200-mesh sieve to ensure the biochar particle size is <75 μm, thus obtaining water onion biochar. Mix the biochar with water at a mass ratio of 1:50, treat the mixture on a shaker at 200 rpm for 2 hours, and filter after the reaction to obtain the water onion biochar-derived dissolved organic matter. The above sample was mixed thoroughly with zero-valent iron (ZVI) at a mass ratio of 5:1, and sulfamethoxazole standard was added to achieve a concentration of 2500 ppb. The mixture was placed in a constant-temperature shaker at 25°C and 200 rpm to simulate the natural degradation process in water. Samples were taken at 240 min, filtered through a 0.22 μm filter membrane, and stored at 4°C. Sulfamethoxazole was detected using high-performance liquid chromatography (HPLC).

[0054] Characterization data of the water onion activated carbon prepared in Examples 1-3 are shown in Table 1.

[0055] Table 1: Biochar Characterization Data

[0056]

[0057] The degradation rate data of sulfamethoxazole in Examples 1-3 and Comparative Examples 1-3 are shown in Table 2.

[0058] Table 2: Degradation rate of sulfamethoxazole

[0059]

[0060] Three-dimensional fluorescence spectroscopy and parallel factor analysis were performed on the DOM prepared in Examples 1-3 at different temperatures (160℃, 180℃, 200℃), yielding three different components (e.g. Figure 4 (As shown in A, B, and C). In Examples 1-3, the biochar prepared by the present invention at 160℃, 180℃, and 200℃ respectively using a hydrothermal method, the biochar-derived dissolved organic matter obtained subsequently, when combined with δ-MnO2, all exhibited superior degradation rates of sulfamethoxazole.

[0061] As can be seen from the comparison of Example 1 and Comparative Examples 1 and 2, compared with the treatment of biochar-derived dissolved organic matter / δ-MnO2 alone, the degradation rate of sulfamethoxazole was significantly improved after the combination of biochar-derived dissolved organic matter and δ-MnO2, proving that the two have a synergistic effect in the removal of sulfamethoxazole in water.

[0062] As can be seen from the comparison between Example 1 and Comparative Example 3, biochar-derived soluble organic matter has a better compounding effect with δ-MnO2 compared with zero-valent iron (ZVI).

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The use of a wetland plant biochar derived dissolved organic matter coupled with delta manganese dioxide water treatment agent to remove sulfamethoxazole from a water body, characterized in that, The water treatment agent is composed of raw materials in the following weight parts: wetland plant biochar derived dissolved organic matter 5-8 parts, delta manganese dioxide 6-9 parts; The preparation method of the wetland plant biochar derived dissolved organic matter comprises the following steps: preparing biochar from wetland plants, immersing the biochar in a solvent, extracting under mechanical vibration / stirring, and collecting the solvent to obtain the wetland plant biochar derived dissolved organic matter. The wetland plants are cattail or reed. The preparation method of the biochar comprises the following step: performing hydrothermal reaction on the wetland plants to obtain the biochar. The hydrothermal reaction is performed at 180-200 ℃ for 12-16 h. The particle size of the biochar is less than 75 μm.

2. The use of wetland plant biochar derived dissolved organic matter coupled δ manganese dioxide water treatment agent to remove sulfamethoxazole from a water body according to claim 1, wherein, After the hydrothermal reaction, the product is collected and dried at 70-80 ℃ for 10-12 h.

3. The use of wetland plant biochar derived dissolved organic matter coupled δ manganese dioxide water treatment agent to remove sulfamethoxazole from a water body as claimed in claim 1, wherein, The solvent is water.

4. The use of wetland plant biochar derived dissolved organic matter coupled δ manganese dioxide water treatment agent to remove sulfamethoxazole from a water body as claimed in claim 1, wherein, The mass ratio of the biochar to the solvent is 1:50-80.

5. The use of wetland plant biochar derived dissolved organic matter coupled δ manganese dioxide water treatment agent to remove sulfamethoxazole from a water body as claimed in claim 1, wherein, The mechanical vibration is performed at 200-300 rpm for 1-2 h.

6. The use of wetland plant biochar derived dissolved organic matter coupled δ manganese dioxide water treatment agent to remove sulfamethoxazole from a water body as claimed in claim 1, wherein, The preparation method of the wetland plant biochar derived dissolved organic matter further comprises filtering with a 0.45 μm filter membrane.

Images