A method and application for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles
The preparation of lignin nanoparticle self-assembly precursors through hydrothermal treatment of straw, which are then directly added to polystyrene nanoplastic solutions, solves the problems of high cost and low biocompatibility of traditional adsorption materials. This achieves efficient removal of polystyrene nanoplastics and resource utilization of solid waste, and is suitable for water pollution control.
Patent Information
- Application Number
- CN202611283865.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-24
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies are insufficient for efficiently removing polystyrene nanoplastics from water. Traditional adsorption materials are costly, have low biocompatibility, and their pore structure is poorly matched with the size of the plastic.
The lignin nanoparticle self-assembly precursor obtained by hydrothermal treatment of straw is directly added to a polystyrene nanoplastic solution. Through self-assembly, lignin nanoparticles are formed, achieving in-situ adsorption and sedimentation of polystyrene nanoplastics, eliminating the need for purification and chemical modification steps.
It achieves efficient removal of polystyrene nanoplastics, reduces secondary pollution from smaller nanoparticles in water, and is suitable for advanced wastewater treatment and in-situ water remediation, realizing the dual effects of solid waste resource utilization and water pollution control.
Smart Images
Figure CN123026286A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of agricultural solid waste resource utilization and water pollution control technology, specifically relating to a method and application for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles. Background Technology
[0002] Polystyrene, a widely used plastic, is a novel environmental pollutant characterized by its persistence and resistance to biodegradation. Its difficult and low recycling rates exacerbate environmental pollution. Researchers have explored numerous methods to remove it from water bodies, including coagulation, oxidation, membrane separation, and adsorption. Adsorption technology has become a research hotspot in recent years due to its ease of operation and controllable cost. However, polystyrene is highly hydrophobic and chemically inert, making it difficult for traditional adsorbent materials to capture it. Some researchers have developed MOF-modified materials, bio-based hydrogels, and nanofibers to adsorb microplastics. While these materials exhibit good plastic adsorption efficiency, they still face challenges such as high synthesis costs, low biocompatibility, and poor matching between pore structure and plastic size. Therefore, the development and application of novel adsorbent technologies with practical value and high efficiency for removing nanoplastics still require further exploration.
[0003] Lignin is the most abundant renewable aromatic organic compound discovered to date. With the development of nanotechnology, the emergence of lignin nanoparticles (LNPs) has provided a new direction for the high-value conversion of lignin. Lignin can be converted into nanoparticles through self-assembly, a simple process that does not involve chemical treatment and represents a good in-situ conversion process for lignin. However, to date, very few studies have been reported on the use of LNPs to remove micro- and nano-plastics from water bodies. To alleviate plastic pollution in water bodies and improve the high-value conversion of lignin from natural solid waste, it is necessary to develop a novel synthetic technology for LNPs to achieve in-situ removal of nanoplastics during the self-assembly process of LNPs. This has significant implications for the remediation of plastic pollution in water bodies and the conversion of high-value lignin from solid waste. Summary of the Invention
[0004] To overcome the above-mentioned technical defects, the present invention provides a method and application for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles.
[0005] The technical solution of the present invention is as follows: One objective of this invention is to provide a method for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles, the method comprising the following steps: S1: The straw is placed in a mixed solution of ethanol, sulfuric acid and water and subjected to hydrothermal treatment at normal pressure, and then filtered to obtain the filtrate; S2: Add the filtrate to a solution containing polystyrene nanoplastics and let it stand in the dark to achieve co-settling of polystyrene and lignin nanoparticles.
[0006] Further specifying, the ratio of straw to mixed solution in S1 is 1 g: (15-25) mL.
[0007] Further specified, the volume ratio of ethanol to water in the mixed solution described in S1 is 1:1, and the amount of sulfuric acid added is 0.4-0.6% of the total volume of ethanol and water.
[0008] Further specified, the hydrothermal treatment temperature in S1 is 90-110℃.
[0009] Further specified, the hydrothermal treatment time in S1 is 0.5-1.5 h.
[0010] Further specify that the dosage of filtrate in S2 is 2.5-40 mL / L.
[0011] Further specifying, the initial concentration of polystyrene nanoplastics in S2 is 1-200 mg / L.
[0012] Further specified, the settling time in S2 is 10 min-2 h.
[0013] Furthermore, the reaction temperature in S2 is room temperature.
[0014] The second objective of this invention is to provide an application of the above-mentioned method in the field of water treatment.
[0015] The advantages of this invention compared to existing technologies are: This invention uses lignin-containing filtrate separated from straw via hydrothermal extraction as a precursor for adsorbing polystyrene nanoplastics. When added to the nanoplastic solution, this precursor self-assembles into lignin nanoparticles, achieving in-situ adsorption and sedimentation of the nanoplastics. This process removes nanoplastics from the water and facilitates the materialization and application of lignin in the filtrate, thus achieving the dual objectives of water pollution control and solid waste resource utilization. Specific advantages are as follows: (1) This invention directly uses straw hydrothermal filtrate as a precursor to self-assemble lignin nanoparticle adsorbents, eliminating the purification and chemical modification steps of lignin in the preparation of traditional lignin-based adsorbents. The filtrate after straw hydrothermal treatment can self-assemble into nanoparticle adsorbents in situ in a solution with water as the antisolvent, and directly adsorb the target pollutants. There is no need to separate and purify the lignin in the filtrate, and the processes of lignin nanoparticle preparation, high-speed separation, and drying are eliminated. Straw raw materials are inexpensive and readily available, the overall process is green, and the additional addition of chemical modification reagents is avoided.
[0016] (2) After being adsorbed in situ, the nanoplastics settle together with the lignin nanoparticles, eliminating the need for external force to achieve solid-liquid separation and reducing secondary pollution from smaller nanoparticles in the water. The nanoparticles generated in situ by lignin combine with polystyrene nanoplastics to aggregate into settleable flocs, which can achieve solid-liquid separation by their own sedimentation alone, without the need for other filtration and separation processes. This avoids secondary pollution from the breakage of nanoplastics and other degradation of smaller plastics, making it suitable for advanced wastewater treatment and in-situ remediation of water bodies. Attached Figure Description
[0017] Figure 1 The fluorescence spectrum of the initial PS-NPs in Example 1; Figure 2a The three-dimensional fluorescence spectrum of the remaining concentration of PS-NPs after reacting with 120EtOH for 2 hours; Figure 2b The three-dimensional fluorescence spectrum of the remaining concentration of PS-NPs after reacting for 2 hours with 100EtOH added; Figure 2c The three-dimensional fluorescence spectrum of the remaining concentration of PS-NPs after reacting with 80EtOH for 2 hours; Figure 3 The two-dimensional fluorescence spectra of the remaining PS-NPs under different dosages of 100EtOH in Example 2 are shown. Figure 4 The removal efficiency of PS-NPs under different dosages of 100EtOH in Example 2; Figure 5 The removal rates of different initial concentrations of PS-NPs under a dosage of 5 mL / L of 100EtOH in Example 3; Figure 6 The adsorption rate of 100EtOH on PS-NPs solution after 30 min of adsorption in Example 4; Figure 7 SEM images of the initial PS-NPs and the adsorption and precipitation products after adding 100 EtOH; (a) initial PS-NPs, (b) after adding 100 EtOH; Figure 8 TEM image of 5 mL / L 100EtOH added to aqueous solution; Figure 9 FTIR spectra of the products after adsorption and precipitation of PS-NPs, 100EtOH in aqueous solution and 100EtOH added to PS-NPs solution. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.
[0020] Example 1: This example demonstrates a method for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles, which is carried out according to the following steps: S1: Add 5g of corn stalks (60 mesh) to a mixed solution of 100mL of ethanol, sulfuric acid and water (ethanol to water volume ratio 1:1, sulfuric acid is 0.5 vol% of the total amount of ethanol and water), heat in a constant temperature oil bath at 100℃ under normal pressure for 1 h, filter through a sieve to obtain the filtrate, and denot it as 100EtOH, which is the precursor for the self-assembly of lignin nanoparticles. S2: Add the filtrate at a concentration of 10 mL / L to a solution containing 50 mg / L polystyrene nanoplastics (PS-NPs), mix well, and let stand in the dark for 2 h. Take the supernatant to test the remaining concentration of PS-NPs.
[0021] Comparative Example 1: The difference between this comparative example and Example 1 is that the treatment temperature in S1 is 120°C, and the filtrate is the precursor for the self-assembly of lignin nanoparticles, denoted as 120EtOH. Other steps and parameters are the same as in Example 1.
[0022] Comparative Example 2 The difference between this comparative example and Example 1 is that the treatment temperature in S1 is 80°C, and the filtrate is the precursor for the self-assembly of lignin nanoparticles, denoted as 80EtOH. Other steps and parameters are the same as in Example 1.
[0023] The initial fluorescence spectra of PS-NPs are as follows: Figure 1 As shown in Figure 2, the fluorescence spectra of the remaining concentrations of PS-NPs after the reactions were completed with the addition of 120EtOH, 100EtOH, and 80EtOH, respectively. Figure 1 Significant PS-NP fluorescence signals were observed at excitation / emission wavelengths of 445 / 487 nm. Fluorescence signals of PS-NPs were also observed after adding 10 mL / L of 120 EtOH, 100 EtOH, and 80 EtOH. Figure 2a , Figure 2b , Figure 2c )Discover, Figure 2bAs shown, when 100EtOH was added, the signal of PS-NPs was not detected, indicating that PS-NPs were completely removed after the addition of 100EtOH, proving the feasibility and effectiveness of the present invention.
[0024] Example 2: Based on Example 1, 100EtOH was selected as the precursor to conduct an experiment on the in-situ removal of polystyrene nanoparticles (PS-NPs) during its self-assembly to form lignin nanoparticles. The dosage of 100EtOH was successively 1 mL / L, 2.5 mL / L, 5 mL / L, 10 mL / L, 20 mL / L, and 40 mL / L. After standing at room temperature for 2 h, the supernatant was taken to test the remaining concentration of PS-NPs. The results are as follows. Figure 3 and Figure 4 As shown. The two-dimensional fluorescence signal intensity of PS-NPs was observed after adding 1 mL / L, 2.5 mL / L, 5 mL / L, 10 mL / L, 20 mL / L, and 40 mL / L of 100EtOH in Example 2. Figure 3 ) and adsorption removal rate ( Figure 4 The results showed that the fluorescence signal intensity of PS-NPs gradually decreased with increasing 100EtOH dosage. The removal rates of PS-NPs by 1 mL / L and 2.5 mL / L 100EtOH were 73% and 94%, respectively. When the dosage was increased to 5 mL / L, the intensity of PS-NPs was 0, indicating that they had been 100% removed. This demonstrates the excellent adsorption properties of the self-assembled lignin nanoparticle precursor of this invention.
[0025] Example 3: Based on Example 2, a dosage of 5 mL / L of 100EtOH was selected to adsorb and remove PS-NPs of different concentrations. The initial concentrations of PS-NPs were 1 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, and 200 mg / L, respectively. The adsorption settling time was 30 min. After the reaction, the supernatant was taken to test the remaining concentration of PS-NPs, and the removal rate was calculated. The results are as follows: Figure 5 As shown in the figure, the data indicates that although the adsorption efficiency decreases with increasing PS-NP concentration, 100% of PS-NPs at concentrations of 1 mg / L, 10 mg / L, and 25 mg / L can still be removed. Furthermore, the removal rates for PS-NPs at concentrations of 50 mg / L and 100 mg / L still exceed 90%, which sufficiently demonstrates the adsorption capacity of this precursor for PS-NPs after forming nanoparticles.
[0026] Example 4: Based on Example 3, 100EtOH was selected as the precursor, with an addition amount of 5 mL / L and an initial concentration of PS-NPs of 10 mg / L. The removal efficiency of PS-NPs at different reaction times was investigated, and the results are as follows: Figure 6 As shown in the figure. The results show that the removal rate of PS-NPs increases with time. When the adsorption time is 10 min, the removal rate can reach 90%, which indicates the rapid adsorption effect of the material on PS-NPs. At 30 min, the adsorption removal efficiency reaches 100%, and then stabilizes at 100%, which reflects the stability of the adsorption effect.
[0027] To demonstrate that 100EtOH is the adsorption effect on PS-NPs during the formation of lignin nanoparticles, SEM tests were performed on PS-NPs before and after the addition of 100EtOH. Figure 7 a shows the initial PS-NPs, which are dispersed, regular spherical particles with uniform size. After the addition of EtOH, a clear aggregation of the PS-NPs can be observed. Figure 7 (b) indicates that the addition of 100EtOH can promote the aggregation of PS-NPs, which is very beneficial for the sedimentation and removal of PS-NPs. Figure 8 The TEM image shows the addition of 5 mL / L of 100EtOH to an aqueous solution, demonstrating that the 100EtOH precursor can generate nanoparticles when added to the PS-NPs solution.
[0028] Further analysis using FTIR results ( Figure 9 This confirms the presence of lignin nanoparticles generated by 100EtOH, and FTIR can reveal the chemical functional groups of the substance. Clearly, the product formed after adding 100EtOH to an aqueous solution contains the characteristic functional group peak of lignin: 3421 cm⁻¹. -1 The OH stretching vibration peak of alcoholic and phenolic hydroxyl groups associated with intermolecular or intramolecular hydrogen bonds at 2926 cm⁻¹ -1 The peak originates from the asymmetric stretching vibration of CH on the methoxy group (OCH3) and aliphatic side chains in the lignin structure, at 1633 cm⁻¹. -1 Absorption peak of a small amount of conjugated carbonyl group on the lignin side chain, 1512 cm⁻¹ -1 The C=C skeleton vibration peak of the aromatic ring, 1238 cm⁻¹ -1 The respiratory vibration peaks and stretching vibration peaks of phenolic CO, belonging to the guaiacyl (G-type unit) aromatic ring, and the peak at 1165 cm⁻¹. -1 and 1122cm -1 The asymmetric stretching vibration peak of the aliphatic ether bond (COC) and 1122 cm⁻¹ -1 The typical characteristic peaks of syringyl (S-type unit) are present. The appearance of these structural peaks and Figure 8The results collectively demonstrate that 100EtOH can form lignin nanoparticles in PS-NPs solution, and these particles contain abundant hydroxyl, methoxy, aryl ether bonds, and aromatic ring units with different substitution types.
[0029] In addition, the precipitate product obtained by mixing 100EtOH with PS-NPs not only contains oxygen-containing functional groups on lignin such as OH, aryl ether bonds (COC), and hydroxyl groups (CO), but also possesses 3000 cm⁻¹ functional groups on the benzene ring of PS-NPs. -1 Nearby unsaturated CH stretching vibration peak. Additionally, at 2924 cm⁻¹... -1 and 2852cm -1 The aliphatic CH stretching vibrations at 758 cm⁻¹ were enhanced, resulting from the superposition of methoxy groups in lignin onto -CH₂-CH⁻ on PS-NPs. -1 and 698cm -1 The extremely sharp double peaks exhibited indicate that the product contains a large amount of polystyrene.
[0030] Comprehensive analysis revealed that when 100EtOH was added to PS-NPs, the 100EtOH not only self-assembled to form lignin nanoparticles, but the PS-NPs also aggregated due to the influence of hydrophobic lignin, thereby promoting the co-precipitation of lignin nanoparticles and PS-NPs. No new chemical covalent bonds were observed in the FTIR spectrum, indicating that physical adsorption occurred between the lignin nanoparticles and PS-NPs.
[0031] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and 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. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for in-situ removal of polystyrene nanoplastics using lignin self-assembled nanoparticles, characterized in that, The method described: S1: Place the straw in a mixed solution of ethanol, sulfuric acid and water and perform hydrothermal treatment at normal pressure, then filter to obtain the filtrate; S2: Add the filtrate to a solution containing polystyrene nanoplastics and let it stand in the dark to achieve co-settling of polystyrene and lignin nanoparticles.
2. The method according to claim 1, characterized in that, The ratio of straw to mixed solution in S1 is 1 g: (15-25) mL.
3. The method according to claim 1, characterized in that, In the mixed solution described in S1, the volume ratio of ethanol to water is 1:1, and the amount of sulfuric acid added is 0.4-0.6% of the total volume of ethanol and water.
4. The method according to claim 1, characterized in that, The hydrothermal treatment temperature in S1 is 90-110℃.
5. The method according to claim 1, characterized in that, The hydrothermal treatment time in S1 is 0.5-1.5 h.
6. The method according to claim 1, characterized in that, The dosage of filtrate in S2 is 2.5-40 mL / L.
7. The method according to claim 1, characterized in that, The initial concentration of polystyrene nanoplastics in S2 is 1-200 mg / L.
8. The method according to claim 1, characterized in that, The settling time in S2 is 10 min-2 h.
9. The method according to claim 1, characterized in that, The reaction temperature in S2 is room temperature.
10. The application of the method according to any one of claims 1-9 in the field of water treatment.