A method for separating glyphosate and glyphosate by adsorption

Abstract

The invention discloses a method for separating glyphosate and glyphosate by adsorption. The method comprises the following steps: using a substrate loaded with an amino-functionalized imidazole-type ionic liquid as an adsorbent to adsorb and treat wastewater containing glyphosate and glyphosate; using an organic acid as an eluent to treat the adsorbent adsorbed with glyphosate and glyphosate, selectively eluting to obtain glyphosate; and then using an inorganic acid / base as an eluent to continue eluting to obtain glyphosate. The method adopts the substrate loaded with an amino-functionalized imidazole-type ionic liquid as an adsorbent to adsorb and treat the wastewater containing glyphosate and glyphosate. The adsorbent has a fast adsorption speed for high-concentration glyphosate or glyphosate solution, can be filled in an adsorption column, is reusable, and can be used in a wide acid-base range.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental engineering, and particularly relates to a method for separating glyphosate and glyphosate by adsorption. Background Art

[0002] Glyphosate is one of the most widely used herbicides on the market. Its non-selective, broad-spectrum properties are distinguished by its high efficiency and low toxicity. In the chemical pesticide industry, the production of glyphosate powder and aqueous glyphosate solutions generates high-concentration phosphine-containing wastewater, whose primary components include 1-2% glyphosate, 3-5% glyphosate-enhanced, and approximately 5% phosphorous acid. These phosphorus-containing compounds not only cause varying degrees of contamination of water sources, soil, air, and ecosystems, but can also damage the human liver and kidneys. Separating and recovering these phosphides could create significant economic value. For example, glyphosate sells for $60,000 per ton, while glyphosate-enhanced sells for $100,000 per ton. Therefore, efficient and sustainable methods for removing phosphides from glyphosate mother liquor are crucial for pollution remediation and resource recovery.

[0003] However, due to the similar properties of phosphides, most current reports on the market extract them together from the mother liquor, but fail to separate them. For example, patent CN102408441A uses an extraction method to add extractants such as methanol and acetone to the glyphosate mother liquor, then heat and distill to remove the solvent, thereby recovering the phosphides in the mother liquor. However, this method does not selectively separate glyphosate and glyphosate.

[0004] How to separate glyphosate and glyphosate while recycling them has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The present invention aims to provide a method for separating glyphosate and glyphosate by adsorption, which uses a specially prepared adsorbent and a targeted eluent to achieve the adsorption and separation of glyphosate and glyphosate.

[0006] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0007] A method for separating glyphosate and glyphosate by adsorption, comprising the following steps:

[0008] (1) Using a substrate loaded with amino-functionalized imidazole-type ionic liquid as an adsorbent to adsorb and treat wastewater containing glyphosate and glyphosate;

[0009] (2) using an organic acid as an eluent to treat the adsorbent adsorbed with glyphosate and glyphosate, and selectively eluting glyphosate;

[0010] (3) Using an inorganic acid / base as an eluent, the adsorbent obtained in step 2 is further treated to obtain glyphosate.

[0011] According to the above scheme, the wastewater containing glyphosate and glyphosate enhancer is the phosphine-containing wastewater generated during the production and use of glyphosate powder or glyphosate aqueous solution.

[0012] According to the above scheme, the amino-functionalized imidazole ionic liquid structure of step 1 is as follows:

[0013]

[0014] Wherein, n is an integer between 1 and 8, and X is Cl, Br, or NO3 - 、BF4、NTf2、PF6、[ZnCl4] 2- 、[FeCl4] - or [AlCl4] - .

[0015] According to the above scheme, the substrate in step 1 is fibers, particles or films of polymer materials.

[0016] According to the above solution, the polymer material is preferably one of microcrystalline cellulose and its derivatives, and polystyrene.

[0017] According to the above scheme, in step 1, the amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner:

[0018] An unsaturated monomer containing an epoxy group is introduced into the surface of the substrate by radiation grafting, and then the amino-functionalized imidazole-type ionic liquid is loaded onto the surface of the resin substrate through an epoxy ring-opening reaction.

[0019] According to the above scheme, in step 1, the amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner:

[0020] Benzyl chloride is introduced into the surface of the substrate, and then the amino-functionalized imidazole ionic liquid is loaded onto the surface of the resin substrate through a halogenation reaction.

[0021] According to the above scheme, in step 1, the amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner:

[0022] The amino-functionalized imidazolium ionic liquid containing double bonds is grafted onto the substrate surface through a grafting reaction.

[0023] According to the above scheme, the organic acid in step 2 is one of formic acid, acetic acid and propionic acid.

[0024] According to the above scheme, the inorganic acid / base in step 3 is one of hydrochloric acid, nitric acid, sodium hydroxide and potassium hydroxide.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention uses a substrate loaded with an amino-functionalized imidazole-type ionic liquid as an adsorbent to perform adsorption treatment on wastewater containing glyphosate and glyphosate. The adsorbent has a fast adsorption rate for high-concentration glyphosate or glyphosate solution, can be filled in an adsorption column, is reusable, and can be used in a wide range of acidity and alkalinity.

[0027] (2) The present invention uses a substrate loaded with amino-functionalized imidazole-type ionic liquid as an adsorbent and simultaneously introduces secondary / tertiary amino and imidazole groups, as well as hydroxyl groups formed by epoxy ring opening. The coexistence of these multifunctional groups can achieve highly selective adsorption and separation of glyphosate and glyphosate, in which the imidazole ring and -NH participate in the adsorption and separation.

[0028] (3) The present invention uses a substrate loaded with amino-functionalized imidazole-type ionic liquid as an adsorbent to adsorb glyphosate and glyphosate, and then uses organic acid and hydrochloric acid to elute glyphosate and glyphosate step by step, thereby achieving the separation of glyphosate and glyphosate.

[0029] (4) The present invention uses a substrate loaded with amino-functionalized imidazole-type ionic liquid as an adsorbent, which has a simple preparation method, easy control of conditions, low energy consumption, safety and environmental protection, and is more suitable for industrial production.

[0030] (5) The present invention uses a substrate loaded with amino-functionalized imidazole-type ionic liquid as an adsorbent raw material, which is easy to obtain, low-cost, and environmentally friendly, meets the needs of filling adsorption columns in industry, and has great industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : Effect of pH on the adsorption of glyphosate and glyphosate mixed solution by two adsorbents.

[0032] Figure 2 :Effects of various eluents on eluting glyphosate and glyphosate.

[0033] Figure 3 : Dynamic column experimental effect diagram of dynamic co-adsorption and step-by-step elution of glyphosate and glyphosate mixed solution by adsorbent.

[0034] Figure 4 : Reusability of resin loaded with amino-functionalized imidazolium ionic liquid for glyphosate and glyphosate. DETAILED DESCRIPTION

[0035] The following examples further illustrate the technical solutions of the present invention but are not intended to limit the scope of protection of the present invention.

[0036] The specific embodiment provides a resin adsorbent loaded with amino-functionalized imidazolium-type ionic liquid:

[0037] (1) 10 g of crystalline cellulose microspheres with a particle size of approximately 150 μm were vacuum-sealed and irradiated with an electron beam using an electron accelerator to generate active free radicals that can be used in the grafting reaction. Irradiation conditions: irradiation voltage 1 MeV, irradiation dose 30 kGy, and dose rate 10 kGy / pass.

[0038] (2) After irradiation, the crystalline cellulose microspheres were immediately placed into a deoxygenated emulsion reaction system consisting of glycidyl methacrylate (GMA): Tween 20: water = 30:3:67 wt% for graft polymerization. The graft polymerization reaction was carried out at 50°C and terminated after approximately 2 hours (when the grafting rate of the substrate reached approximately 250%). The microspheres were then rinsed with water to obtain an adsorbent precursor.

[0039] (3) The above-mentioned adsorbent precursor was mixed with 20 ml of a mixed solution of ethanol and water (ethanol:water 2:1) and 10 g of 1-aminoethyl-3-vinylimidazolium bromide to undergo an epoxy ring-opening reaction. The reaction was shaken at 80°C for 24 hours. The mixture was removed, washed with ethanol and water, and dried to obtain an amino-functionalized imidazole-type ionic liquid-supported resin ([AE]Br). The functional group density of the [AE]Br resin was 1.87 mmol / g-ad. The resulting resin was white spherical with a particle size of approximately 400 μm.

[0040] The specific embodiment also provides another resin adsorbent loaded with amino-functionalized imidazolium-type ionic liquid:

[0041] By replacing 1-aminoethyl-3-vinylimidazolium bromide with 1-aminopropyl-3-vinylimidazolium bromide as the reactive monomer, another amino-functionalized imidazolium-based ionic liquid-supported resin ([AP]Br) was obtained. The [AP]Br functional group density was 1.78 mmol / g-ad. The resulting resin was white, spherical, and had a particle size of approximately 400 μm.

[0042] Example 1

[0043] A static adsorption test was conducted by weighing 0.01 g of the prepared amino-functionalized imidazolium ionic liquid-supported resin into a 10 mL aqueous solution containing glyphosate and glyphosate-enhanced at room temperature. The pH was adjusted between 1 and 12 using dilute acid and base. The adsorption test was conducted under stirring at room temperature. After 24 hours of adsorption, the glyphosate concentration was measured using a UV spectrophotometer. The concentration was then used to calculate the resin adsorption capacity (Qe).

[0044] The adsorption of phosphide by amino-functionalized imidazole ionic liquid-supported resin is affected by pH. Figure 1As shown in the figure, it can be seen that these two aminoimidazole ionic liquid adsorbents show ultra-high adsorption affinity for glyphosate in the binary mixed adsorption of glyphosate and glyphosate. At the molar concentration of glyphosate and glyphosate, they can adsorb most of the glyphosate in the mixed solution. Figure 1 It can be seen that at a pH of 3 to 10, both ionic liquid adsorbents exhibit high adsorption activity, indicating that the adsorbents can be used in a wide range of acid and base.

[0045] Example 2

[0046] In order to study how to separate the adsorbed glyphosate and glyphosate, different eluents were used to elute the resin adsorbed with glyphosate and glyphosate. In the elution experiment, 10 mg of amino-functionalized imidazole-type ionic liquid loaded resin was used to adsorb 10 mL of glyphosate and glyphosate at a concentration of 200 mg / L and at the optimal adsorption pH. The adsorption time was 24 hours. After the adsorption was completed, 10 mL of various commonly used eluents at a concentration of 1 mol / L were added, placed in a constant temperature oscillator, taken out after 24 hours, and the concentrations of glyphosate and glyphosate in the solution were measured. The elution experiment results are shown in Figure 2. Figure 2 As shown, it can be seen that the organic acid (acetic acid) has different elution effects on glyphosate and glyphosate, and can selectively elute glyphosate.

[0047] Example 3

[0048] Based on the phenomenon that organic acid acetic acid can selectively elute glyphosate, a binary dynamic column experiment was conducted to separate the adsorbed glyphosate and glyphosate by step-by-step elution. First, the adsorbent was loaded into the column, and a binary mixed solution of glyphosate and glyphosate was passed through at a uniform speed. After a certain period of adsorption, the adsorbent now contained glyphosate and glyphosate. At this time, acetic acid was first passed through at a uniform speed to selectively elute glyphosate until no more glyphosate was eluted; then the elution was continued with inorganic acid to elute the glyphosate in the adsorbent. Thus, the effect of separating glyphosate and glyphosate was achieved. The results of the dynamic column experiment are shown in the figure. Figure 3 shown.

[0049] Example 4

[0050] In order to study the reusability of amino-functionalized imidazole ionic liquid-loaded resin, 5 adsorption-desorption-adsorption cycles were performed. In each adsorption experiment, 10 mg of amino-functionalized imidazole ionic liquid-loaded resin was used to adsorb 10 mL of glyphosate and glyphosate at a concentration of 200 mg / L and at the optimal adsorption pH. The adsorption time was 24 hours. After the adsorption was completed, 10 mL of HCl at a concentration of 1 mol / L was added, and the solution was placed in a constant temperature oscillator. After 24 hours, it was taken out and the concentrations of glyphosate and glyphosate in the solution were measured. The adsorbent was then washed with deionized water 5 times to remove the HCl adsorbed on the surface, and the next adsorption experiment was carried out. The adsorption experiment results are shown in Figure 2. Figure 4 As shown in the figure, after 5 cycles of adsorption-desorption, the adsorption capacity of the amino-functionalized imidazole ionic liquid-loaded resin for glyphosate and glyphosate still remained above 90%, indicating that they have good reusability.

Claims

1. A method for separating glyphosate and glyphosate by adsorption, characterized in that The following steps are involved: (1) Using a substrate loaded with amino-functionalized imidazole ionic liquid as an adsorbent to treat wastewater containing glyphosate and glyphosate-enhanced; (2) Using organic acid as eluent to treat the adsorbent adsorbed with glyphosate and glyphosate-enhanced, and selectively elute glyphosate; (3) Using an inorganic acid / base as an eluent, the adsorbent obtained in step (2) is further treated to obtain glyphosate.

2. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein The wastewater containing glyphosate and glyphosate enhancer is phosphine-containing wastewater generated during the production and use of glyphosate powder or glyphosate aqueous solution.

3. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein The amino-functionalized imidazole ionic liquid in step 1 has the following structural formula: Wherein, n is an integer between 1 and 8, and X is Cl, Br, NO3, BF4, NTf2, PF6, ZnCl4, FeCl4 or AlCl4.

4. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein The substrate in step (1) is a fiber, particle or film of a polymer material.

5. The method for separation of glyphosate and glyphosate by adsorption according to claim 4, characterized in that The polymer material is one of microcrystalline cellulose and its derivatives and polystyrene.

6. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein Step (1) The amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner: An unsaturated monomer containing an epoxy group is introduced into the surface of the substrate by radiation grafting, and then the amino-functionalized imidazole-type ionic liquid is loaded onto the surface of the resin substrate through an epoxy ring-opening reaction.

7. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein Step (1) The amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner: Benzyl chloride is introduced into the surface of the substrate, and then the amino-functionalized imidazole ionic liquid is loaded onto the surface of the resin substrate through a halogenation reaction.

8. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein Step (1) The amino-functionalized imidazole ionic liquid is loaded onto the substrate surface in the following manner: The amino-functionalized imidazolium ionic liquid containing double bonds is grafted onto the substrate surface through a grafting reaction.

9. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein The organic acid in step (2) is one of formic acid, acetic acid and propionic acid.

10. The method for separation of glyphosate and glyphosate by adsorption according to claim 1, wherein The inorganic acid / base in step (3) is one of hydrochloric acid, nitric acid, sodium hydroxide and potassium hydroxide.

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