Glyphosate adsorbing material as well as preparation method and application thereof

Abstract

The invention discloses a glyphosate adsorption material with salt tolerance and a wide pH application range, which is prepared by taking D202 macroporous strong base II type styrene anion exchange resin as a carrier and loading a metal oxide, the preparation method comprises the following steps: pre-treating D202 macroporous strong base II type styrene anion exchange resin with ethanol, distilled water, a sodium hydroxide solution and a sodium chloride solution respectively, and drying; preparing a metal salt solution, and loading metal salt into pores of the exchange resin by a dipping-evaporation drying method; dispersing into an alkaline solution, stirring and reacting, filtering, washing and drying to obtain the glyphosate adsorbing material. The prepared adsorbing material has ultrahigh salt tolerance and a wide pH application range, the adsorption rate of 60% is still kept when the NaCl concentration is 16 wt%, and the adsorbing material is almost not influenced by the salt concentration at all; the removal rate is kept at 60% or above when the pH value is 3-12, and the effect is kept in a full-pH range and under a high-salt condition; and the adsorbent still has a good adsorption effect when being directly used for adsorbing the glyphosate acid alkali amphoteric mother liquor.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a glyphosate adsorbent material and its preparation and application. Background Technology

[0002] Glyphosate is the most widely used herbicide globally due to its broad spectrum, high efficiency, and low toxicity. On one hand, glyphosate, after application, is highly water-soluble and enters the human body through water and the food chain, causing toxic effects on the nervous and endocrine systems. On the other hand, in the industrial production of glyphosate, to achieve the crystallization separation and purification of the target product, the process often involves acidification, alkalization, and multi-step salting-out / crystallization operations, ultimately producing two typical mother liquors characterized by "high salinity + extreme pH + high glyphosate concentration": acidic mother liquor and alkaline mother liquor. Existing mother liquor treatment technologies generally convert organophosphorus into inorganic phosphorus through deep oxidation technology for recovery. The selling price of organophosphorus in the waste liquor is far higher than that of inorganic phosphates, but there are few reports on the recovery of high-value organophosphorus from the mother liquor. Therefore, the resource utilization treatment of organophosphorus in acidic and alkaline glyphosate mother liquor has significant environmental and economic value.

[0003] Although various types of adsorbents are used for the separation of glyphosate, such as inorganic materials (activated carbon, graphene), natural polymers (nanocellulose), commercial resins (D201, D301), and novel materials such as MOF, the large amounts of acidic or alkaline mother liquor generated during glyphosate production are characterized by extreme pH, high salinity and ionic strength, and complex coexisting components. This easily leads to insufficient selectivity, adsorption capacity decay, or the need for strict pH conditions with conventional adsorbents. Existing engineering treatments often require neutralization, desalination, or multi-step pretreatment of the mother liquor before combining it with precipitation / membrane separation / oxidation units to reduce the load and achieve compliant discharge. However, these methods generally suffer from high reagent consumption, increased salt load and secondary wastewater, long process length, and high operating costs. Therefore, there is an urgent need for a material and method that can adapt to the complex conditions of glyphosate production mother liquor, can be directly added and used, and achieve efficient adsorption and recovery, in order to reduce treatment costs and improve resource utilization. Summary of the Invention

[0004] The large amounts of acidic or alkaline mother liquor generated during glyphosate production are characterized by extreme pH, high salinity and ionic strength, and complex coexisting components. This can easily lead to insufficient selectivity, adsorption capacity decay, or the need for strict pH conditions in conventional adsorbent materials. Existing engineering treatments often require neutralization, desalination, or multi-step pretreatment of the mother liquor before proceeding with precipitation / membrane separation / oxidation units to reduce load and achieve compliant discharge. However, these methods generally suffer from high reagent consumption, increased salt load and secondary wastewater, long process duration, and high operating costs. Addressing the lack of commercially available glyphosate adsorbents that can directly treat glyphosate mother liquor, this invention provides a glyphosate adsorbent material with salt tolerance and a wide effective pH range, along with its preparation method, capable of directly treating amphoteric glyphosate mother liquor.

[0005] A glyphosate adsorbent material with salt tolerance and a wide pH range was prepared by loading metal oxides onto a D202 macroporous strong base type II styrene-based anion exchange resin.

[0006] The present invention also provides a method for preparing the above-mentioned glyphosate adsorbent material, comprising the following steps: (1) The D202 macroporous strong base type II styrene anion exchange resin was pretreated with distilled water, sodium hydroxide solution and sodium chloride solution respectively, and then dried; (2) Prepare a metal salt solution and load the metal salt into the pores of the exchange resin by impregnation-evaporation method; (3) Disperse the glyphosate adsorbent into an alkaline solution and stir to react. After filtration, washing and drying, the glyphosate adsorbent is obtained.

[0007] According to the above scheme, the particle size of the D202 macroporous strong base type II styrene-based anion exchange resin in step (1) is 0.315-1.25 mm, the volume exchange capacity is above 1.0 mmol / mL, and the wet true density is 1.07-1.12 g / mL.

[0008] According to the above scheme, the pretreatment in step (1) includes soaking in distilled water, sodium hydroxide solution and sodium chloride solution at 20-40℃ for 10-30 minutes in sequence, wherein the concentration of sodium hydroxide solution is 3-5wt% and the concentration of sodium chloride solution is 7-10wt%.

[0009] According to the above scheme, the impregnation-evaporation method in step (2) includes immersing the exchange resin in the metal salt solution and heating and stirring until the solution is evaporated.

[0010] According to the above scheme, the metal salt in step (2) is a combination of one or more of iron salt, lanthanum salt, cerium salt, neodymium salt, and yttrium salt. Neodymium salt is preferred.

[0011] According to the above scheme, the metal salt solution in step (2) uses ethanol / water solution as solvent, the preparation temperature is 50-60℃, and the stirring speed is 300-400rpm to avoid local agglomeration.

[0012] According to the above scheme, the alkaline solution in step (3) is an aqueous solution of sodium hydroxide or potassium hydroxide with a concentration of 0.1-1M.

[0013] According to the above scheme, the stirring reaction temperature in step (3) is 20-50℃, and the reaction time is 24-48 hours.

[0014] The present invention also provides the application of the above-mentioned glyphosate adsorbent material in the glyphosate separation process, including separating and recovering glyphosate in acidic glyphosate mother liquor, alkaline glyphosate mother liquor or glyphosate-polluted wastewater using the glyphosate adsorbent material.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention selects D202 macroporous strong base type II styrene-based anion exchange resin as the loading material to load metals. The synthesis method is simple and the conditions are easy to control.

[0016] By optimizing the solvent, the dispersibility and stability of metal salts within the D202 macroporous strong base type II styrene anion exchange resin can be improved.

[0017] The adsorbent material prepared by this invention has extremely high salt tolerance and a wide pH range. It still maintains an adsorption rate of 60% when the NaCl concentration is 16wt%, and is almost completely unaffected by the salt concentration. It maintains a removal rate of more than 60% at pH (3-12) and maintains its effectiveness under high salt and full pH range. It still has a good adsorption effect when directly used to adsorb glyphosate acid-base amphoteric mother liquor.

[0018] The resin described in this invention can be used directly in the acidic or alkaline glyphosate production mother liquor without prior neutralization, dilution, or complex pretreatment. It maintains good adsorption capacity, adsorption rate, and selectivity even under conditions of high salt, high ionic strength, and complex coexisting impurities, thereby significantly reducing the amount of acid-base adjustment agents used, reducing the salt load increase and secondary wastewater generation caused by neutralization, simplifying the process and reducing operating costs. At the same time, after the resin is saturated, it can be efficiently desorbed and regenerated using conventional desorbents and recycled, facilitating the enrichment and recovery of target components and the reduction of mother liquor load. It has the advantages of strong adaptability, good stability, and ease of engineering scale-up and continuous operation. Attached Figure Description

[0019] Figure 1 The adsorbent prepared in Example 1 adsorbs glyphosate solutions at different pH values.

[0020] Figure 2Example 1: Adsorption of glyphosate solutions with different salt concentrations by the adsorbent prepared.

[0021] Figure 3 Comparison of the adsorption performance of different resins on acidic mother liquor for glyphosate production.

[0022] Figure 4 Comparison of the adsorption performance of different resins on the alkaline mother liquor for glyphosate production.

[0023] Figure 5 : The recyclability of the adsorbent prepared in Example 1. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0025] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0026] The D202 macroporous strong base type II styrene-based anion exchange resin used in the specific embodiment was produced by Jiangsu Linhai Resin Technology Co., Ltd., and was sold in the form of Cl type. The particle size was 0.315-1.25 mm, the volume exchange capacity was 1.2 mmol / mL, and the wet true density was 1.07-1.12 g / mL.

[0027] A specific embodiment provides a pretreatment for D202 macroporous strong base type II styrene-based anion exchange resin: Ⅰ. Before loading the column, clean the equipment and pipes with water to prevent harmful substances from contaminating the resin, and at the same time drain the water from the equipment. II. Add ethanol to the adsorption column in an amount equivalent to 0.3 to 0.4 times the volume of the packed resin, then add fresh resin to the exchange column. Maintain the liquid level 100 to 200 mm above the resin layer, and then soak for 2 hours.

[0028] Ⅲ. Use 2 BV of ethanol to pass through the resin layer at a flow rate of 2 BV / h, and soak the resin in the last part of the ethanol solution for 2-4 hours.

[0029] IV. Pass ethanol through the resin bed at a flow rate of 2 BV / h until the effluent does not turn white and cloudy when water is added. Then wash the ethanol bed with pure water at a flow rate of 2 BV / h until no ethanol is present in the effluent.

[0030] V. Soak the resin layer for 1-2 hours with 2 BV of 3-5 wt% NaOH solution at a flow rate of 2 BV / h, then rinse with pure water at a flow rate of 1-2 BV / h until the pH of the effluent is neutral.

[0031] VI. Pass 2 BV of 7-10 wt% NaCl solution through the resin bed at a flow rate of 2 BV / h. Soak the resin in the last portion of sodium chloride solution for 2-4 hours. Rinse with pure water at a flow rate of 2-4 BV / h until the pH of the effluent is neutral.

[0032] VII. Dry the resin at 50~60℃ before use.

[0033] VIII. If the resin is running continuously, the above treatment is not necessary. However, if the resin is to be out of use for an extended period of time, the above treatment should be repeated.

[0034] Example 1 Preparation of metal-supported resin: Weigh D202 resin and pretreat it using distilled water, NaOH solution, and NaCl solution. Weigh 2.1 g of NdCl3 and dissolve it in 30 mL of ethanol / water solution (20% by volume). Add 1 g of D202 resin and stir at 60 °C until the solution evaporates to dryness. Redisperse the solution in 30 mL of NaOH solution (10% by mass) and stir at room temperature for 48 h. Wash with deionized water, then rinse with NaCl solution, and finally wash with ethanol. Dry at 60 °C to obtain the adsorbent HNdO@D202 resin.

[0035] Preparation of metal-supported resin: Weigh D2O2 resin and pretreat it using distilled water, NaOH solution, and NaCl solution. Weigh 1.5g LaCl3 and dissolve it in 30mL of ethanol / water solution (20% by volume). Add 1g of D2O2 resin and stir at 60℃ until the solution evaporates to dryness. Redisperse the solution in 30mL of NaOH solution (10% by mass) and stir at room temperature for 24h. Wash with deionized water, rinse with NaCl solution, and finally wash with ethanol. Dry at 60℃ to obtain the adsorbent La2O3@D2O2 resin.

[0036] Preparation of metal-supported resin: Weigh D202 resin and pretreat it using distilled water, NaOH solution, and NaCl solution. Weigh 1.7 g Ce(NH4)2(NO3)4 and dissolve it in 30 mL of ethanol / water solution (20% by volume). Add 1 g of D202 resin and stir at 60 °C until the solution evaporates to dryness. Redisperse the solution in 30 mL of NaOH solution (10% by mass) and stir at room temperature for 24 h. Wash with deionized water, then rinse with NaCl solution, and finally wash with ethanol. Dry at 60 °C to obtain the adsorbent CeO2@D202 resin.

[0037] Preparation of metal-supported resin: Weigh D202 resin and pretreat it using distilled water, NaOH solution, and NaCl solution. Weigh 1.4 g ZrCl3 and dissolve it in 30 mL of ethanol / water solution (20% by volume). Add 1 g of D202 resin and stir at 60 °C until the solution evaporates to dryness. Redisperse the solution in 30 mL of NaOH solution (10% by mass) and stir at room temperature for 24 h. Wash with deionized water, then rinse with NaCl solution, and finally wash with ethanol. Dry at 60 °C to obtain the adsorbent ZrO2@D202 resin.

[0038] Example 2 Adsorption of glyphosate solutions at different pH values ​​by the resin: 10 mg of the adsorbent obtained in Example 1 was added to a 10 mL adsorption glass bottle, followed by 10 mL of 50 mg / L glyphosate solution. The bottle was then placed in a constant temperature shaking bed and shaken at 160 rpm for 24 h at 30 °C. The concentration was measured using the total phosphorus method. All adsorption experiments were performed in parallel, and the average value was calculated. D202 resin was used as a control group.

[0039] The pH range was adjusted from 1 to 14 using dilute acids and alkalis to control the adsorption of glyphosate solution with a concentration of 150 mg / L at different pH values. The effect of pH on the adsorption of glyphosate by the adsorbent obtained in Example 1 is as follows: Figure 1 As shown in the figure, the adsorption efficiency of HNdO@D202 resin initially increases and then decreases with increasing pH, reaching a peak at pH=3. Compared to D202 resin, loading with HNdO significantly improves the adsorption efficiency of glyphosate under acidic conditions while maintaining a considerable adsorption efficiency under alkaline conditions, achieving an adsorption rate of 70% at pH=11. Overall, HNdO@D202 exhibits stable and efficient glyphosate adsorption performance over a wide pH range (3 to 12).

[0040] Example 3 Adsorption of glyphosate solutions by resins at different salt concentrations: Glyphosate solutions with NaCl concentrations ranging from 0% to 16% were prepared by adding different masses of NaCl. The adsorption performance of D2O2 and HNdO@D2O2 on glyphosate at different salt concentrations was as follows: Figure 2 As shown in the figure, the salt resistance of HNdO@D202 resin is significantly improved compared to D202 resin, and it still maintains a removal rate of 30% when the salt concentration is 16%.

[0041] Example 4 Adsorption and separation of glyphosate from actual glyphosate mother liquor wastewater by resin: 50 mg of the adsorbent obtained in Example 1 was added to acidic and alkaline glyphosate mother liquors (the concentrations of glyphosate in the acidic and alkaline mother liquors were 7520 mg / L and 13190 mg / L, respectively). The adsorption effect was as follows: Figure 3 , 4 As shown, the removal rates of glyphosate in the acidic and alkaline mother liquors were 11.397% and 6.5%, respectively. The HNdO@D202 resin still exhibited excellent adsorption performance for glyphosate in acidic and alkaline mother liquors under conditions of high salt and extreme pH.

[0042] Comparative Example 1 Consistent with the method in Example 4, the metal-supported resin was replaced with D202 resin, and it was found that the recovery rate of glyphosate in acidic and alkaline glyphosate mother liquor by D202 resin was 0.

[0043] Comparative Example 2 Consistent with the method in Example 4, the metal-supported resin was replaced with D301 resin, and it was found that the recovery rate of glyphosate in acidic and alkaline glyphosate mother liquor by D301 resin was 0.

[0044] Comparative Example 3 Consistent with the method in Example 4, the metal-supported resin was replaced with HNdO@D301 resin, and it was found that the glyphosate recovery rate of HNdO@D301 resin in acidic and alkaline glyphosate mother liquor was 0.

[0045] Comparative Example 4 Consistent with the method in Example 4, the metal-supported resin was replaced with 330 resin, and it was found that the 330 resin had a glyphosate recovery rate of 0 in the acidic and alkaline glyphosate mother liquor.

[0046] Comparative Example 5 Consistent with the method in Example 4, the metal-supported resin was replaced with HNdO@330 resin, and it was found that the glyphosate recovery rate of HNdO@330 resin in acidic and alkaline glyphosate mother liquor was 0.

[0047] Example 5 Resin recyclability: Multiple sets of 50 mg / L glyphosate solutions were prepared and added to the solution from Example 1 for repeated adsorption tests (without replacement). The adsorption data after multiple cycles are shown below. Figure 5 As shown in the figure, HNdO@D202 resin still exhibits extremely high stability and a long service life after 50 cycles.

Claims

1. A glyphosate adsorbent material with salt tolerance and a wide pH range, characterized in that... The metal oxide was loaded onto D202 macroporous strong base type II styrene-based anion exchange resin as a carrier.

2. The method for preparing the glyphosate adsorbent material according to claim 1, characterized in that... Includes the following steps: (1) The D202 macroporous strong base type II styrene anion exchange resin was pretreated with ethanol, distilled water, sodium hydroxide solution and sodium chloride solution respectively, and then dried; (2) Prepare a metal salt solution and load the metal salt into the pores of the exchange resin by impregnation-evaporation method; (3) Disperse the glyphosate adsorbent into an alkaline solution and stir to react. After filtration, washing and drying, the glyphosate adsorbent is obtained.

3. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... The D202 macroporous strong base type II styrene-based anion exchange resin in step (1) has a particle size of 0.315-1.25 mm, a volume exchange capacity of more than 1.0 mmol / mL, and a wet true density of 1.07-1.12 g / mL.

4. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... Step (1) pretreatment includes soaking in distilled water, sodium hydroxide solution and sodium chloride solution at 20-40℃ for 10-30 minutes in sequence. The concentration of sodium hydroxide solution is 3-5 wt% and the concentration of sodium chloride solution is 7-10 wt%.

5. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... Step (2) The impregnation-evaporation method includes immersing the ion exchange resin in the metal salt solution and heating and stirring until the solution evaporates to dryness.

6. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... The metal salt in step (2) is one or more of the following: iron salt, lanthanum salt, cerium salt, neodymium salt, and yttrium salt.

7. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... The metal salt solution in step (2) uses ethanol / water solution as solvent, is prepared at a temperature of 50-60℃, and is stirred at a speed of 300-400rpm.

8. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... The alkaline solution in step (3) is an aqueous solution of sodium hydroxide or potassium hydroxide with a concentration of 0.1-1M.

9. The method for preparing the glyphosate adsorbent material as described in claim 2, characterized in that... Step (3) The stirring reaction temperature is 20-50℃ and the reaction time is 24-48 hours.

10. The application of the glyphosate adsorbent material according to claim 1 in the glyphosate separation process includes directly separating and recovering glyphosate from acidic glyphosate mother liquor, alkaline glyphosate mother liquor, or glyphosate-polluted wastewater using the glyphosate adsorbent material.

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