A method for removing glyphosate from water

Abstract

The present invention discloses a method for removing glyphosate from water, belonging to the field of wastewater treatment technology. The method adds the adsorbent Zr-SA / Ce-UIO-66 to a dual-system aqueous solution containing phosphate and glyphosate. During the adsorption process, the OH groups in the adsorbent undergo a substitution reaction with phosphate ions, forming a complex between the adsorbent and the phosphoric acid. The complex and ionic glyphosate adsorb glyphosate ions through various mechanisms, such as electrostatic attraction, hydrogen bonding, complexation, and coprecipitation, achieving synergistic removal of phosphate and glyphosate.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for removing glyphosate from water. Background Art

[0002] Glyphosate (N-(phosphonomethyl)glycine) is one of the most widely used herbicides worldwide and a common organophosphorus pesticide (OPP) in agriculture. Due to its widespread and inappropriate use worldwide, glyphosate has seriously contaminated water and farmland soil. Excessive phosphate concentrations in aquatic environments have been identified as a key factor in eutrophication. However, some researchers have pointed out that degraded glyphosate can also contribute to eutrophication due to its bioavailability in water. Currently, strategies for removing glyphosate from water include adsorption, chemical precipitation, membrane separation, and biological treatment. However, among these removal methods, adsorption is the most attractive due to its simplicity, relatively low cost, and high removal efficiency. Furthermore, adsorption is applicable to wastewater treatment technologies with varying concentrations and types of pollutants. The adsorbent can be efficiently regenerated through gentle methods after use, making it a wastewater treatment technology suitable for large-scale deployment. However, since the mechanism of glyphosate-induced eutrophication of water bodies is still unclear and the removal technology of glyphosate is relatively limited, the present invention aims to explore a method based on Zr-SA / Ce-UIO-66 adsorbent that can simultaneously remove glyphosate and phosphate. Summary of the Invention

[0003] In view of the above shortcomings of the prior art, the present invention provides a method for removing glyphosate from water.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for removing glyphosate from water comprises the following steps: mixing a phosphate-containing aqueous solution and a glyphosate-containing aqueous solution to obtain a mixed solution, then adding a Zr-SA / Ce-UIO-66 adsorbent to the mixed solution, performing oscillation adsorption for 13-15 hours, and then performing solid-liquid separation to achieve removal of glyphosate from the water.

[0006] As a preferred embodiment of the present invention, the phosphate-containing aqueous solution is a phosphate solution or a phosphate-contaminated water body; the glyphosate-containing aqueous solution is a glyphosate solution or a glyphosate-contaminated water body.

[0007] As a preferred embodiment of the present invention, in the mixed solution, the mass concentration ratio of glyphosate to phosphate is 2:(1-4).

[0008] More preferably, the mass concentration ratio of glyphosate to phosphate is 1:2.

[0009] As a preferred embodiment of the present invention, the mass concentration ratio of the Zr-SA / Ce-UIO-66 adsorbent to phosphate is (5-10): (10-20).

[0010] As a preferred embodiment of the present invention, the pH of the contaminated liquid is 3-10.

[0011] More preferably, the pH of the contaminated liquid is 6.

[0012] As a preferred embodiment of the present invention, the Zr-SA / Ce-UIO-66 adsorbent is Zr 4+ Zr-SA / Ce-UIO-66 is formed by cross-linking with Ce-UIO-66 aerogel wrapped by sodium alginate.

[0013] As a preferred embodiment of the present invention, the preparation method of the Zr-SA / Ce-UIO-66 adsorbent comprises the following steps:

[0014] (1) Weigh ammonium cerium nitrate and dissolve it in water, dissolve terephthalic acid in DMF, pour the ammonium cerium nitrate solution into the terephthalic acid solution and stir to mix evenly; react at 90-110°C for 20-40 minutes, centrifuge, wash, remove the precipitate, and dry it to obtain Ce-UIO-66;

[0015] (2) dissolving sodium alginate and Ce-UIO-66 in water respectively and then mixing them evenly to obtain a suspension;

[0016] (3) Using a syringe, the suspension was dropped into a zirconium oxychloride octahydrate solution for cross-linking at room temperature to form hydrogel microbeads; after washing, freeze-drying was performed to obtain Zr-SA / Ce-UIO-66.

[0017] As a preferred embodiment of the present invention, the mass ratio of the ammonium cerium nitrate to terephthalic acid is (1-1.4): (0.2-0.5).

[0018] As a preferred embodiment of the present invention, the mass ratio of sodium alginate to Ce-UIO-66 is (1.6-2.2): (0.3-0.5).

[0019] As a preferred embodiment of the present invention, the mass concentration of the zirconium oxychloride octahydrate solution is 2-5%, and the volume ratio of the suspension to the zirconium oxychloride octahydrate solution is 20:100.

[0020] As a preferred embodiment of the present invention, the room temperature cross-linking time is 24 hours.

[0021] As a preferred embodiment of the present invention, the freeze-drying temperature is -40 to -50°C.

[0022] Compared with existing technologies, the present invention has the following beneficial effects: After mixing glyphosate-containing water with phosphate water, the Zr-SA / Ce-UIO-66 adsorbent is added. The -OH groups in the Zr-SA / Ce-UIO-66 adsorbent undergo a substitution reaction with phosphate ions, forming a complex between the adsorbent and the phosphate. The complex and ionic glyphosate absorb glyphosate ions through various mechanisms, such as electrostatic attraction, hydrogen bonding, complexation, and coprecipitation, achieving synergistic removal of phosphate and glyphosate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The glyphosate removal rate and Zeta potential diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate single system and the Zeta potential diagram in a glyphosate system coexisting with phosphate; (a) The glyphosate removal rate of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate single system; (b) The Zeta potential diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate single system; (c) The Zeta potential diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate system coexisting with phosphate.

[0024] Figure 2 The figure shows the effect of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 on the removal of glyphosate at different initial phosphate concentrations or different initial pH conditions and the removal effect of phosphate; (a) The figure shows the removal effect of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 on glyphosate and phosphate at different initial phosphate concentrations; (b) The figure shows the removal effect of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 on the removal of glyphosate at different initial phosphate concentrations and different initial pH conditions.

[0025] Figure 3 This is the adsorption kinetics diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate system coexisting with phosphate.

[0026] Figure 4 This is the adsorption isotherm of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate system in the presence of phosphate.

[0027] Figure 5This is a cyclic stability diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 in a glyphosate system with coexistence of phosphate, and a diagram showing the overflow effect of Ce and Zr ions in the adsorbent; (a) is a cyclic stability diagram of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 for glyphosate removal in a glyphosate system with coexistence of phosphate prepared in UP water, and in simulated wastewater; (b) is a diagram showing the overflow effect of Ce and Zr ions in the adsorbent within 25 hours of adsorption time.

[0028] Figure 6 FT-IR graphs of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1, the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 after adsorbing glyphosate, the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 after adsorbing phosphate, and the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 after adsorbing glyphosate and phosphate.

[0029] Figure 7 XPS spectra of the Zr-SA / Ce-UIO-66 adsorbent prepared in Example 1 before and after adsorption of glyphosate and phosphate; (a) is the full spectrum; (b) is the XPS spectrum of P 2p; (c) is the XPS spectrum of Zr 3d; and (d) is the XPS spectrum of O1s.

[0030] Figure 8 This is the adsorption mechanism diagram of the Zr-SA / Ce-UIO-66 adsorbent for the adsorption of the binary system of glyphosate and phosphate. DETAILED DESCRIPTION

[0031] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0032] Example 1

[0033] A method for preparing a sodium alginate composite adsorbent comprises the following steps:

[0034] (1) Weigh 1.2 g of cerium ammonium nitrate and dissolve it in 30 mL of deionized water. Dissolve 0.4 g of terephthalic acid in 50 mL of DMF. Pour the cerium ammonium nitrate solution into the terephthalic acid solution and stir to mix. After reacting at 110°C for 30 min, centrifuge the precipitate, wash it three times with DMF and deionized water, and then dry it in vacuum at 100°C for 24 h to obtain Ce-UIO-66.

[0035] (2) 1.6 g of sodium alginate and 0.4 g of the cerium-based metal organic framework Ce-UIO-66 obtained in step (1) were dissolved in 70 mL and 30 mL of deionized water, respectively, to form respective aqueous solutions. The above solutions were then mixed and mechanically stirred at 400 rpm for 24 h to obtain a mixed suspension.

[0036] (3) Using a syringe, 10 mL of the suspension was dropped into a 4% zirconium oxychloride octahydrate solution and cross-linked at room temperature for 24 h. The suspension was then washed three times with deionized water and placed in a freeze dryer at -49.2°C for 24 h to obtain a Zr-SA / Ce-UIO-66 adsorbent.

[0037] Example 2

[0038] A method for preparing a sodium alginate composite adsorbent comprises the following steps:

[0039] (1) Weigh 1.0 g of cerium ammonium nitrate and dissolve it in 50 mL of deionized water. Dissolve 0.6 g of terephthalic acid in 70 mL of DMF. Pour the cerium ammonium nitrate solution into the terephthalic acid solution and stir to mix. After reacting at 90°C for 40 min, centrifuge the precipitate, wash it three times with DMF and deionized water, and then dry it in vacuum at 110°C for 24 h to obtain Ce-UIO-66.

[0040] (2) 1.2 g of sodium alginate and 0.2 g of the cerium-based metal organic framework Ce-UIO-66 obtained in step (1) were dissolved in 50 mL and 50 mL of deionized water, respectively, to form respective aqueous solutions. The above solutions were then mixed and mechanically stirred at 400 rpm for 24 h to obtain a mixed suspension.

[0041] (3) Using a syringe, 30 mL of the suspension was dropped into a 2% zirconium oxychloride octahydrate solution and cross-linked at room temperature for 24 h. The suspension was then washed with deionized water five times and placed in a freeze dryer at -40°C for 24 h to obtain a Zr-SA / Ce-UIO-66 adsorbent.

[0042] Example 3

[0043] A method for preparing a sodium alginate composite adsorbent comprises the following steps:

[0044] (1) Weigh 1.4 g of cerium ammonium nitrate and dissolve it in 30 mL of deionized water. Dissolve 0.2 g of terephthalic acid in 30 mL of DMF. Pour the cerium ammonium nitrate solution into the terephthalic acid solution and stir to mix. After reacting at 110°C for 20 min, centrifuge the precipitate, wash it three times with DMF and deionized water, and then dry it in vacuum at 90°C for 24 h to obtain Ce-UIO-66.

[0045] (2) 2 g of sodium alginate and 0.6 g of the cerium-based metal organic framework Ce-UIO-66 obtained in step (1) were dissolved in 90 mL and 30 mL of deionized water, respectively, to form respective aqueous solutions. The above solutions were then mixed and mechanically stirred at 400 rpm for 24 h to obtain a mixed suspension.

[0046] (3) Using a syringe, 50 mL of the suspension was dropped into a 5% zirconium oxychloride octahydrate solution and cross-linked at room temperature for 24 h. The suspension was then washed with deionized water five times and placed in a freeze dryer at -50°C for 24 h to obtain a Zr-SA / Ce-UIO-66 adsorbent.

[0047] Comparative Example 1

[0048] A method for preparing a Ce-UIO-66 adsorbent comprises the following steps:

[0049] Weigh 1.2g of cerium ammonium nitrate and dissolve it in 30mL of deionized water. Dissolve 0.4g of terephthalic acid in 50mL of DMF. Pour the cerium ammonium nitrate solution into the terephthalic acid solution and stir to mix thoroughly. After reacting at 110°C for 30 minutes, centrifuge the precipitate, wash it three times with DMF and deionized water, and then vacuum dry it at 100°C for 24 hours to obtain Ce-UIO-66 adsorbent.

[0050] Comparative Example 2

[0051] A method for preparing a sodium alginate composite adsorbent comprises the following steps:

[0052] (1) Weigh 1.2 g of cerium ammonium nitrate and dissolve it in 30 mL of deionized water. Dissolve 0.4 g of terephthalic acid in 50 mL of DMF. Pour the cerium ammonium nitrate solution into the terephthalic acid solution and stir to mix. After reacting at 110°C for 30 min, centrifuge the precipitate, wash it three times with DMF and deionized water, and then dry it in vacuum at 100°C for 24 h to obtain Ce-UIO-66.

[0053] (2) 1.6 g of sodium alginate and 0.4 g of the cerium-based metal organic framework Ce-UIO-66 obtained in step (1) were dissolved in 70 mL and 30 mL of deionized water, respectively, to form respective aqueous solutions. The above solutions were then mixed and mechanically stirred at 400 rpm for 24 h to obtain a mixed suspension, which was placed in a freeze dryer at -49.2°C and dried for 24 h to obtain a SA / Ce-UIO-66 adsorbent.

[0054] Effect Example 1

[0055] Test samples: materials prepared in Examples 1-3 and Comparative Examples 1-2.

[0056] A method for removing glyphosate from water comprises the following steps: adding 0 mg / L, 5 mg / L, 10 mg / L or 20 mg / L phosphate solution to a 10 mg / L glyphosate solution to obtain a mixed solution; adjusting the pH to 3, 4, 5, 6, 7, 8, 9 or 10, respectively; adding 20 mg / L of an adsorbent to the mixed solution; shaking the solution at a speed of 180 rpm for 15 hours in a constant temperature shaking incubator; performing solid-liquid separation to remove glyphosate from the water; and testing the concentrations of glyphosate and phosphate in the separated solution to obtain glyphosate and phosphate removal rates.

[0057] like Figure 1 As shown in (a), when the phosphate concentration in the mixed solution is 0 mg / L, the Zr-SA / Ce-UIO-66 adsorbent has a certain affinity for glyphosate, and the removal rate remains above 40%. The removal efficiency of glyphosate is highest at pH 6, reaching about 46%. In aqueous solutions with different pH values, the amino groups (NH-R) and phosphates (PO4 3- -R) and carboxyl (-COOH) groups undergo protonation and deprotonation reactions, presenting different forms and relative contents in aqueous solutions, where their relative amounts mainly depend on the pH value of the solution. When the pH of the solution is greater than 5.6, glyphosate exists mainly in the form of anions in the solution. Combined with the Zeta potential diagram before and after adsorption ( Figure 1 (b) Before adsorption, the adsorbent surface was positively charged at a pH below 6.8. However, glyphosate exists as an anionic ion in solution at a pH of 6, so electrostatic attraction is the primary adsorption mechanism at this pH. After the adsorption reaction, the isoelectric point of the adsorbent shifted to 3, indicating that significant ion exchange occurred during the adsorption process.

[0058] like Figure 2 (b) It can be seen that when the phosphate concentration in the mixed solution is 5 mg / L, the effect of Zr-SA / Ce-UIO-66 in adsorbing and removing glyphosate is improved. In a wider pH range (3-10), the glyphosate removal rate of the adsorbent is increased to more than 50%, and the glyphosate removal rate reaches the highest at pH 6, reaching 58%. When the phosphate concentration is 10 mg / L, the glyphosate removal effect of the adsorbent increases to more than 60%, and the adsorption removal rate reaches a peak at pH 6. When the phosphate concentration in the mixed solution is 20 mg / L, Zr-SA / Ce-UIO-66 has the best affinity for glyphosate, and the adsorption removal effect of glyphosate reaches a peak. In a wider pH range (3-10), the glyphosate removal rate is maintained above 70%, and the adsorbent has the highest glyphosate removal rate at pH 6, reaching 75%. As Figure 2(a) It can be seen that in the glyphosate-phosphate coexistence water environment experiment, Zr-SA / Ce-UIO-66 not only enhances the specific adsorption of glyphosate, but also still efficiently removes phosphate from the solution. In the phosphate-glyphosate coexistence water environment, the pH dependence of Zr-SA / Ce-UIO-66 in the adsorption and removal of glyphosate is higher than that of phosphate adsorption experiments. In addition, due to the presence of phosphate in the solution, the adsorption behavior of Zr-SA / Ce-UIO-66 in removing glyphosate is synergistically promoted. Moreover, the presence of glyphosate does not have a negative effect on the removal of phosphate, and the removal of phosphate is as high as more than 90%. Combined with the Zeta potential diagram analysis before and after adsorption of the adsorbent ( Figure 1 (c) During the adsorption of glyphosate by Zr-SA / Ce-UIO-66, an ion exchange reaction occurs, resulting in a significant loss of positive charge on the adsorbent surface. Therefore, electrostatic attraction is one of the adsorption mechanisms. In a single phosphate aqueous solution system, the adsorbent prepared in Example 1 achieved a phosphate removal efficiency exceeding 90%.

[0059] from Figure 3 As can be seen, the adsorption equilibrium time for glyphosate in its single system is approximately 13 hours. In the initial stage of the adsorption process, due to a lack of adsorption sites, glyphosate loading onto the adsorbent is relatively slow, reaching saturation after 13 hours. The adsorption equilibrium time for glyphosate in its dual system is approximately 15 hours. In the initial stage of the adsorption process, glyphosate adsorption onto the adsorbent proceeds rapidly, with rapid adsorption reaching equilibrium after approximately 6 hours. The adsorption rate remains relatively slow throughout the entire adsorption phase from 6 to 15 hours, reaching saturation at 15 hours. Compared to the glyphosate single system, the presence of 20 mg / L phosphate significantly enhances the adsorbent's glyphosate removal efficiency. Furthermore, the presence of phosphate significantly enhances the adsorption rate of glyphosate removal in the initial stage of adsorption and significantly increases the adsorption capacity of the adsorbent, reaching 11.2 mg / g at saturation. Therefore, in the dual system with phosphate, Zr-SA / Ce-UIO-66 is capable of achieving rapid and efficient glyphosate removal.

[0060] In the presence of 20 mg / L phosphate at a pH of 6, the glyphosate removal efficiency of Examples 2-3 reached over 70%, and the phosphate removal efficiency was over 90%. Furthermore, the phosphate and glyphosate removal performance of the materials prepared in Examples 2-3 was also relatively weakly dependent on pH in the presence of both phosphate and glyphosate. In a single phosphate aqueous solution system, the adsorbent prepared in Examples 2-3 achieved a phosphate removal efficiency exceeding 90%.

[0061] In the material prepared in Comparative Example 1, the adsorbent had limited affinity for glyphosate in a single aqueous solution of glyphosate, resulting in poor removal efficiency and difficulty in recycling. Adding phosphate to the glyphosate solution did not effectively promote glyphosate removal. In a single aqueous phosphate solution, the adsorbent achieved a phosphate removal rate exceeding 80%, but the adsorbent was difficult to recycle.

[0062] The adsorbent prepared in Comparative Example 2 has a low molding effect and lacks the effect of cross-linking ions, making it difficult to prepare into a composite material. In a single aqueous solution system of glyphosate, the adsorbent has a poor removal effect on glyphosate, and adding phosphate to the glyphosate solution has not been found to effectively promote the removal of glyphosate.

[0063] according to Figure 6-7 , it can be seen from FT-IR that after glyphosate is adsorbed in the phosphate-glyphosate binary system, there is an intermolecular hydrogen bond force in the Zr-SA / Ce-UIO-66 adsorbent. Different from the adsorption of single glyphosate, the hydrogen bond at 515 cm -1 and 603cm -1 A new characteristic peak appears at 1225cm, which is due to the enhanced tensile strength of Ce-O / OPO bond, indicating that Ce and P are well combined. -1 A new characteristic peak appears at the Zr-SA / Ce-UIO-66 adsorbent, resulting from asymmetric bending vibrations of the C-O bond. This difference is primarily dependent on the presence of phosphate in the solution. When phosphate is present, the intermolecular hydrogen bonding of the Zr-SA / Ce-UIO-66 adsorbent is enhanced, and the complex formed between the adsorbent and phosphate enhances its specific adsorption performance for glyphosate. XPS results, comparing the full XPS spectra of the Zr-SA / Ce-UIO-66 adsorbent before and after glyphosate adsorption, reveal a new P 2p characteristic peak in the XPS spectrum after glyphosate adsorption, effectively demonstrating that P is successfully captured by the adsorbent. Furthermore, the carbon atom content in the glyphosate-loaded adsorbent decreases, indicating the effective participation of carbon-based functional groups in the adsorption process. Conversely, the oxygen and nitrogen atom contents increase, demonstrating the successful loading of phosphate oxyanions and various forms of oxygenated glyphosate ions onto the adsorbent, indicating that intermolecular hydrogen bonding is a primary adsorption mechanism. Figure 7 (b) It can be seen that no P 2p peak was found on the Zr-SA / Ce-UIO-66 adsorbent before adsorption, but the P 2p peak was clearly found in the adsorption after the adsorption experiment and a certain degree of shift occurred, indicating that the P element was effectively captured by the Zr-SA / Ce-UIO-66 adsorbent. Figure 7(c) It can be seen that the Zr 3d fine spectrum shows double peaks centered at 182.7eV and 185.1eV, which belong to the Zr 3d of the unused adsorbent, 5 / 2 and Zr 3d 3 / 2 The binding energy of Zr shifts before and after adsorption, indicating that Zr is involved in the adsorption behavior. Figure 7 (d) indicates that oxygen-containing functional groups participate in glyphosate adsorption. The peak area at 531.6 eV decreases significantly after adsorption. This is due to a substitution reaction between the -OH groups in the adsorbent and the phosphate ions, forming a complex between the adsorbent and the phosphate. This complex, combined with ionic glyphosate, adsorbs the glyphosate ions through various mechanisms (such as electrostatic attraction and complexation), achieving synergistic removal of phosphate and glyphosate.

[0064] Effect Example 2

[0065] Test sample: the material prepared in Example 1.

[0066] A method for removing glyphosate from water comprises the following steps: adding a 20 mg / L phosphate solution to a 5-100 mg / L glyphosate solution to obtain a mixed solution, adjusting the pH to 6, then adding 20 mg / L of an adsorbent to the mixed solution, shaking the solution at a speed of 180 rpm for 15 hours in a constant temperature shaking incubator, then performing solid-liquid separation to remove the glyphosate from the water, and testing a glyphosate adsorption isotherm.

[0067] like Figure 4 As shown, the glyphosate adsorption capacity increases with increasing initial concentration. Under experimental conditions with the presence of phosphate, the adsorption capacity of the Zr-SA / Ce-UIO-66 adsorbent for glyphosate is significantly enhanced. Across the full range of glyphosate concentrations, the presence of phosphate promotes glyphosate removal by the adsorbent, with the maximum adsorption capacity reaching 38 mg / g, approximately 50% higher than the maximum adsorption capacity of 21 mg / g under experimental conditions without phosphate addition. The presence of phosphate in the dual system enhances the affinity of the Zr-SA / Ce-UIO-66 adsorbent for glyphosate, synergistically promoting its adsorption behavior.

[0068] Effect Example 3

[0069] Test samples: materials prepared in Examples 1-3 and Comparative Examples 1-2.

[0070] A method for removing glyphosate from water comprises the following steps: adding 0 mg / L, 5 mg / L, 10 mg / L or 20 mg / L of phosphate to 10 mg / L of simulated wastewater containing glyphosate to obtain a mixed solution, wherein the simulated wastewater also contains 10 mg / L of Na + , 5mg / LK + 、10mg / L Ca2+ 、5mg / L Mg 2+ 、10mg / L Cl - , 5mg / LSO4 2- , adjust the pH of the mixed solution to 6, then add 20 mg / L of adsorbent to the mixed solution, oscillate at 180 rpm in a constant temperature shaking incubator for 15 hours, and then perform solid-liquid separation to achieve the removal of glyphosate in the water body, and test the glyphosate adsorption isotherm.

[0071] A method for removing glyphosate from water comprises the following steps: adding 0 mg / L, 5 mg / L, 10 mg / L or 20 mg / L of phosphate to a 10 mg / L glyphosate UP aqueous solution to obtain a mixed solution, adjusting the pH to 6, then adding 20 mg / L of an adsorbent to the mixed solution, shaking the solution at a speed of 180 rpm for 15 hours in a constant temperature shaking incubator, then performing solid-liquid separation to remove the glyphosate from the water, and testing a glyphosate adsorption isotherm.

[0072] Figure 5 (a) It was found that in the absence of phosphate, the removal effect in the simulated wastewater was slightly lower than that in the glyphosate UP aqueous solution. After three simulated wastewater cycle experiments, the removal rate of glyphosate by Zr-SA / Ce-UIO-66 adsorbent was reduced to 30%, indicating that the simulated wastewater had a certain effect on the removal of glyphosate by Zr-SA / Ce-UIO-66 adsorbent. Moreover, after multiple cycle experiments, the active sites in the adsorbent were relatively reduced, resulting in a significant decrease in the removal effect after multiple cycles. In addition, the presence of multiple components in the simulated wastewater (such as Na + , K + , Ca 2+ , Mg 2+ , Cl - , SO4 2- ,HPO4 2-Interference from phosphate and other organic components reduced the glyphosate removal efficiency of the Zr-SA / Ce-UIO-66 adsorbent. However, in the dual system with phosphate and glyphosate, the Zr-SA / Ce-UIO-66 adsorbent exhibited a stronger enhancement on glyphosate removal in the simulated wastewater than in the single system. This also demonstrates that the phosphate-enhancing effect on glyphosate did not negatively impact the simulated wastewater. Three cycles of simulated wastewater testing revealed minimal impact of the adsorbent on glyphosate removal, maintaining good adsorption capacity for both glyphosate and phosphate. This demonstrates the stability and reproducibility of the prepared Zr-SA / Ce-UIO-66 adsorbent in simulated wastewater. Furthermore, the adsorption performance of phosphate in the simulated wastewater was relatively stable, with no significant change in the phosphate removal efficiency of the Zr-SA / Ce-UIO-66 adsorbent. The adsorbent maintained high phosphate removal efficiency, and the presence of glyphosate did not significantly affect the adsorption. Figure 5 (b) It is known that in the dual system of phosphate and glyphosate coexistence, the amount of metal Ce and Zr overflowing from the Zr-SA / Ce-UIO-66 adsorbent within the experimental period of 25 h is low and can be ignored.

[0073] In Example 2-3, in the simulated wastewater with a pH of 6 and the presence of 20 mg / L phosphate, the glyphosate removal rate did not change much compared to the glyphosate UP aqueous solution, and the phosphate removal rate did not change.

[0074] The material prepared in Comparative Example 1 has a poor removal effect on glyphosate in simulated wastewater, and the promotion effect is even less obvious. In addition, the effect decreases significantly in the recycling experiment. This is mainly because the prepared adsorbent has poor recycling performance and is not conducive to recycling and reuse.

[0075] The material prepared in Comparative Example 2 is difficult to synthesize into an uncomposite material, and it is also difficult to demonstrate the affinity of the adsorbent to glyphosate in application.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for removing glyphosate from water, characterized in that: The method comprises the following steps: mixing a phosphate-containing aqueous solution and a glyphosate-containing aqueous solution to obtain a mixed solution, then adding a Zr-SA / Ce-UIO-66 adsorbent to the mixed solution, oscillating and adsorbing for 13-15 hours, and then performing solid-liquid separation to remove glyphosate from the water body; the Zr-SA / Ce-UIO-66 adsorbent is Zr 4+ Zr-SA / Ce-UIO-66 is formed by cross-linking with Ce-UIO-66 aerogel wrapped by sodium alginate.

2. The method for removing glyphosate from water according to claim 1, wherein: In the mixed solution, the mass concentration ratio of glyphosate to phosphate is 2:(1-4).

3. The method for removing glyphosate from water according to claim 1, wherein: The mass concentration ratio of the Zr-SA / Ce-UIO-66 adsorbent to phosphate is (5-10): (10-20).

4. The method for removing glyphosate from water according to claim 1, wherein: The pH of the mixed solution is 3-10.

5. The method for removing glyphosate from water according to any one of claims 1 to 4, characterized in that: The preparation method of the Zr-SA / Ce-UIO-66 adsorbent comprises the following steps: (1) Weigh ammonium cerium nitrate and dissolve it in water, dissolve terephthalic acid in DMF, pour the ammonium cerium nitrate solution into the terephthalic acid solution and stir to mix evenly; react at 90-110°C for 20-40 minutes, centrifuge, wash, remove the precipitate, and dry it to obtain Ce-UIO-66; (2) Sodium alginate and Ce-UIO-66 were dissolved in water respectively, and then mixed evenly to obtain a suspension; (3) Use a syringe to drop the suspension into zirconium oxychloride octahydrate solution for room temperature cross-linking to form hydrogel microbeads; after washing, freeze-drying is performed to obtain Zr-SA / Ce-UIO-66.

6. The method for removing glyphosate from water according to claim 5, wherein: The mass ratio of the ammonium cerium nitrate to terephthalic acid is (1-1.4): (0.2-0.5).

7. The method for removing glyphosate from water according to claim 5, wherein: The mass ratio of the sodium alginate to Ce-UIO-66 is (1.6-2.2): (0.3-0.5).

8. The method for removing glyphosate from water according to claim 5, wherein: The mass concentration of the zirconium oxychloride octahydrate solution is 2-5%, and the volume ratio of the suspension to the zirconium oxychloride octahydrate solution is 20:

100.

9. The method for removing glyphosate from water according to claim 5, wherein: The cross-linking time at room temperature is 24 hours.

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