Bipolar membrane electrodialysis treatment method for glyphosate salt-containing wastewater

Abstract

The invention discloses a bipolar membrane electrodialysis treatment method for glyphosate salt-containing wastewater, which comprises the following steps: (1) aerating the glyphosate salt-containing wastewater and then filtering to obtain primarily treated glyphosate salt-containing wastewater; (2) softening and filtering the primarily treated glyphosate salt-containing wastewater to obtain softened and hardness-removed glyphosate salt-containing wastewater; (3) conveying the glyphosate salt-containing wastewater subjected to softening and hardness removal into a salt chamber of bipolar membrane electrodialysis equipment for desalting treatment, and enabling chloride ions to selectively penetrate through an anion exchange membrane to reach an acid chamber under the action of an electric field to be combined with hydrogen ions generated by a bipolar membrane to generate hydrochloric acid, sodium ions selectively penetrate through the cation exchange membrane to reach the alkali chamber under the action of an electric field and are combined with hydroxyl ions generated by the bipolar membrane to generate sodium hydroxide, and acid liquor, alkali liquor and a salt solution are recycled; and (4) filtering the salt solution by using a homogeneous membrane, recovering glyphosate, and carrying out evaporative crystallization on the residual solution to obtain a crystallized phosphate product.

Description

Technical Field

[0001] The invention relates to the technical field of saline wastewater treatment, and in particular to a bipolar membrane electrodialysis treatment method for glyphosate saline wastewater. Background Art

[0002] There are four main production processes for glyphosate, namely the chloroacetic acid method, the iminodiacetic acid method, the dialkyl phosphite method and the trialkyl phosphite method. Among them, the dialkyl phosphite method uses polyformaldehyde, glycine, and dialkyl phosphite as raw materials, triethylamine as a catalyst, and obtains glyphosate through addition, condensation, and acidolysis. This process is relatively simple, with relatively less wastewater, high yield, low cost, and good product quality. Therefore, this process method is mainly used in China. However, one of the biggest problems with this process method is the treatment of the mother liquor after acidolysis, crystallization, and filtration to obtain the glyphosate original drug. The mother liquor after glyphosate crystallization is a strongly acidic liquid containing a large amount of triethylamine, hydrochloric acid, and glyphosate. Triethylamine is an important catalyst, and it is expensive and needs to be recycled. The currently commonly used method for treating glyphosate mother liquor is to neutralize it with liquid alkali to a pH greater than 10, and triethylamine is separated from the solution as an oil phase, and glyphosate-containing saline wastewater is produced after separation. The glyphosate-containing saline wastewater also contains 1-3% glyphosate, about 1% triethylamine, and more than 10% sodium chloride. At present, the existing technology for treating glyphosate-containing saline wastewater is to concentrate it again, increase the concentration of glyphosate to about 5%, separate sodium chloride crystals, add glyphosate original drug to adjust the glyphosate concentration to 7% or 10%, and sell it as a 7% or 10% glyphosate aqueous solution. Since the 7% or 10% glyphosate aqueous solution contains almost saturated sodium chloride, long-term use will cause soil salinization and hardening, causing adverse effects on the environment. Furthermore, the neutralization treatment method of the mother liquor after glyphosate crystallization only recovers the triethylamine therein, while the raw hydrochloric acid used for acidic hydrolysis cannot be recycled but becomes sodium chloride or other chloride pollutants, which not only generates solid waste, but also causes the 7% or 10% glyphosate aqueous solution to contain a large amount of sodium chloride or other chlorides, which harms the environment. More importantly, neutralizing this part of hydrochloric acid also consumes additional liquid alkali, which increases the production cost. Moreover, when using liquid alkali for neutralization, the liquid alkali contains a large amount of water, which increases the total amount of wastewater, thereby increasing the energy consumption of concentration. Summary of the invention

[0003] In view of this, the present invention provides a bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater to solve the above-mentioned problems.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater comprises the following steps:

[0006] (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter to obtain preliminarily treated glyphosate-containing saline wastewater;

[0007] (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it with a second microporous filter to obtain softened and de-hardened glyphosate-containing saline wastewater;

[0008] (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in an interval of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and an electrolyte solution of a certain concentration is injected into the electrode chamber. The cathode and anode of the bipolar membrane electrodialysis device are respectively connected to the direct current. The negative electrode and the positive electrode of the DC power source are connected, and the current density of the DC electric field is controlled to be 10-40 mA / cm2 and the temperature is 15-40° C. The bipolar membrane electrodialysis equipment is started, and the chloride ions selectively pass through the anion exchange membrane under the action of the electric field to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid, and the sodium ions selectively pass through the cation exchange membrane under the action of the electric field to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered;

[0009] (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

[0010] Furthermore, in step (1), the pore size of the first microporous filter is 1 to 50 μm.

[0011] Furthermore, in the step (2), the crystallization nuclei in the fluidized crystallization bed include at least one of silica sand, granular calcite and quartz sand, and the particle size of the crystallization nuclei is 0.2-0.5 mm.

[0012] Furthermore, in the step (2), the pore size of the second microporous filter is 0.2-1 μm.

[0013] Furthermore, in step (3), the thickness of the anion exchange membrane is 0.1 to 0.13 mm, and the surface resistance is 0.1 to 0.9 Ω / cm 2 , selective permeability is greater than 96%.

[0014] Furthermore, in step (3), the thickness of the cation exchange membrane is 0.08-0.1 mm, and the surface resistance is 0.5-3 Ω / cm 2 , selective permeability is greater than 98%.

[0015] Furthermore, in step (3), the bipolar membrane has a thickness of 0.2 to 0.25 mm and a surface resistance of 0.5 to 2 Ω / cm 2 .

[0016] Furthermore, the electrolyte solution circulating in the electrode chamber in step (3) is a sodium sulfate solution.

[0017] Furthermore, in the step (3), the separators between the inner membranes of the bipolar membrane electrodialysis device are made of elastic, insulating and corrosion-resistant materials.

[0018] Furthermore, the cathode and anode of the bipolar membrane electrodialysis device in step (3) are composed of a titanium-coated ruthenium anode and a stainless steel cathode.

[0019] The beneficial effects of the present invention are:

[0020] The present invention firstly uses a fluidized crystallization bed to soften and remove the hardness of glyphosate-containing saline wastewater, solid particles such as silica sand, granular calcite and quartz sand are added into the fluidized bed reactor, and calcium and magnesium ions are effectively removed by adsorption and coprecipitation. Then, the softened and de-hardened glyphosate-containing saline wastewater is subjected to electrodialysis using a bipolar membrane, and a potential difference is generated on both sides of the saline wastewater by the action of an electric field, and the potential difference is used as a driving force to make anions and cations in the saline wastewater pass through the ion exchange membrane for directional migration, and the salt ions in the saline wastewater are separated. At the same time, under the action of a direct current electric field, a water dissociation process occurs at the interface of the intermediate catalytic layer of the bipolar membrane, hydrogen ions and hydroxide ions are generated, and selectively enter the acid chamber and the alkali chamber under the action of the electric field; anions in the salt solution enter the adjacent acid chamber through the anion exchange membrane, and the hydrogen ions dissociated from the bipolar membrane generate acid; cations in the salt solution enter the alkali chamber through the cation exchange membrane, and the hydroxide ions dissociated from the bipolar membrane generate alkali. The water molecules consumed in the dissociation process of the bipolar membrane are replenished by permeating from the surrounding solution to the middle of the membrane. Under the action of the electric field, ions migrate continuously. After a period of reaction, the effluent from the salt chamber is an organic solution or inorganic solution with a low salt concentration, the effluent from the acid chamber is a high-concentration acid solution, and the effluent from the alkali chamber is a high-concentration alkali solution, completing the desalination process of the high-concentration salt solution and generating the corresponding acid and alkali, thereby effectively removing sodium chloride from the glyphosate-containing saline wastewater. The method for treating glyphosate-containing saline wastewater has the advantages of high desalination efficiency, sustainable production, and cost savings, and has the potential for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Figure 1 It is a schematic structural diagram of a bipolar membrane in a bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater according to the present invention;

[0023] Figure 2 The present invention is a working principle diagram of a bipolar membrane electrodialysis device in a bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater. DETAILED DESCRIPTION

[0024] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.

[0025] The present invention provides a bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater, comprising the following steps:

[0026] (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter with a pore size of 1 to 50 μm to obtain preliminarily treated glyphosate-containing saline wastewater;

[0027] (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it using a second microporous filter with a pore size of 0.2 to 1 μm to obtain softened and de-hardened glyphosate-containing saline wastewater;

[0028] (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in an interval of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and an electrolyte solution of a certain concentration is injected into the electrode chamber. The cathode and anode of the bipolar membrane electrodialysis device are respectively connected to the direct current. The negative electrode and the positive electrode of the DC power source are connected, and the current density of the DC electric field is controlled to be 10-40 mA / cm2 and the temperature is 15-40° C. The bipolar membrane electrodialysis equipment is started, and the chloride ions selectively pass through the anion exchange membrane under the action of the electric field to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid, and the sodium ions selectively pass through the cation exchange membrane under the action of the electric field to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered;

[0029] (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

[0030] The crystal nuclei in the fluidized crystallization bed include at least one of silica sand, granular calcite and quartz sand, and the particle size of the crystal nuclei is 0.2-0.5 mm; the thickness of the anion exchange membrane in the bipolar membrane electrodialysis device is 0.1-0.13 mm, and the surface resistance is 0.1-0.9 Ω / cm 2 , the permselectivity is greater than 96%, the thickness of the cation exchange membrane is 0.08-0.1mm, and the surface resistance is 0.5-3Ω / cm 2 , the permeability is greater than 98%, the thickness of the bipolar membrane is 0.2-0.25mm, and the surface resistance is 0.5-2Ω / cm 2 The electrolyte solution circulating in the electrode chamber is sodium sulfate solution, the separator between the membranes is made of elastic insulating and corrosion-resistant material, and the electrodes are composed of titanium-coated ruthenium anode and stainless steel cathode.

[0031] Example 1

[0032] In this embodiment, the thickness of the anion exchange membrane in the bipolar membrane electrodialysis device is 0.1 mm and the surface resistance is 0.1 Ω / cm 2 The thickness of the cation exchange membrane is 0.08 mm and the surface resistance is 0.5 Ω / cm 2 The thickness of the bipolar membrane is 0.2 mm and the surface resistance is 0.5 Ω / cm 2 . .

[0033] A bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater in this embodiment comprises the following steps:

[0034] (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter with a pore size of 1 μm to obtain preliminarily treated glyphosate-containing saline wastewater;

[0035] (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it using a second microporous filter with a pore size of 0.2 μm to obtain softened and de-hardened glyphosate-containing saline wastewater;

[0036] (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in intervals of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and a certain concentration of electrolyte solution is injected into the electrode chamber to separate the cathode and anode of the bipolar membrane electrodialysis device. The two chambers are connected to the negative electrode and the positive electrode of the DC power supply respectively, and the current density of the DC electric field is controlled to be 10 mA / cm2 and the temperature to be 15°C. The bipolar membrane electrodialysis equipment is started. Under the action of the electric field, the chloride ions selectively pass through the anion exchange membrane to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid. Under the action of the electric field, the sodium ions selectively pass through the cation exchange membrane to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered;

[0037] (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

[0038] The NaCl removal rate in this example is 98.9%.

[0039] Example 2

[0040] In this embodiment, the thickness of the anion exchange membrane in the bipolar membrane electrodialysis device is 0.11 mm and the surface resistance is 0.5 Ω / cm 2 The thickness of the cation exchange membrane is 0.09 mm and the surface resistance is 1.5 Ω / cm 2 The thickness of the bipolar membrane is 0.23 mm and the surface resistance is 1 Ω / cm 2 .

[0041] A bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater in this embodiment comprises the following steps:

[0042] (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter with a pore size of 25 μm to obtain preliminarily treated glyphosate-containing saline wastewater;

[0043] (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it using a second microporous filter with a pore size of 0.6 μm to obtain softened and de-hardened glyphosate-containing saline wastewater;

[0044] (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in intervals of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and a certain concentration of electrolyte solution is injected into the electrode chamber to separate the cathode and anode of the bipolar membrane electrodialysis device. The two chambers are connected to the negative electrode and the positive electrode of the DC power supply, respectively, and the current density of the DC electric field is controlled to be 25 mA / cm2 and the temperature to be 25°C. The bipolar membrane electrodialysis equipment is started. Under the action of the electric field, the chloride ions selectively pass through the anion exchange membrane to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid. Under the action of the electric field, the sodium ions selectively pass through the cation exchange membrane to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered;

[0045] (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

[0046] The NaCl removal rate in this example is 99.7%.

[0047] Example 3

[0048] In this embodiment, the thickness of the anion exchange membrane in the bipolar membrane electrodialysis device is 0.13 mm and the surface resistance is 0.9 Ω / cm 2 The thickness of the cation exchange membrane is ~0.1mm and the surface resistance is 3Ω / cm 2 The thickness of the bipolar membrane is 0.25 mm and the surface resistance is 2 Ω / cm 2 .

[0049] A bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater in this embodiment comprises the following steps:

[0050] (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter with a pore size of 50 μm to obtain preliminarily treated glyphosate-containing saline wastewater;

[0051] (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it using a second microporous filter with a pore size of 1 μm to obtain softened and de-hardened glyphosate-containing saline wastewater;

[0052] (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in intervals of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and a certain concentration of electrolyte solution is injected into the electrode chamber to separate the cathode and anode of the bipolar membrane electrodialysis device. The two chambers are connected to the negative electrode and the positive electrode of the DC power supply respectively, and the current density of the DC electric field is controlled to be 40 mA / cm2 and the temperature to be 40°C. The bipolar membrane electrodialysis equipment is started. Under the action of the electric field, the chloride ions selectively pass through the anion exchange membrane to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid. Under the action of the electric field, the sodium ions selectively pass through the cation exchange membrane to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered;

[0053] (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

[0054] The NaCl removal rate in this example is 99.2%.

[0055] It can be seen from Examples 1 to 3 that the removal rate of sodium chloride in glyphosate-containing saline wastewater by the method of the present invention is more than 98%. The present invention first uses a fluidized crystallization bed to soften and remove the hardness of glyphosate-containing saline wastewater, and solid particles such as silica sand, granular calcite and quartz sand are added to the fluidized bed reactor to effectively remove calcium and magnesium ions by adsorption and coprecipitation. The softened and de-hardened glyphosate-containing saline wastewater is then subjected to electrodialysis using a bipolar membrane. The electric field is used to generate a potential difference on both sides of the saline wastewater. With the potential difference as the driving force, the anions and cations in the saline wastewater are directed to migrate through the ion exchange membrane, and the salt ions in the saline wastewater are separated. At the same time, under the action of the DC electric field, a water dissociation process occurs at the interface of the intermediate catalytic layer of the bipolar membrane, generating hydrogen ions and hydroxide ions, which selectively enter the acid chamber and the alkaline chamber under the action of the electric field; the anions in the salt solution enter the adjacent acid chamber through the anion exchange membrane, and generate acid with the hydrogen ions dissociated from the bipolar membrane; the cations in the salt solution enter the alkaline chamber through the cation exchange membrane, and generate base with the hydroxide ions dissociated from the bipolar membrane. The water molecules consumed in the dissociation process of the bipolar membrane are replenished by permeating from the surrounding solution to the middle of the membrane. Under the action of the electric field, ions migrate continuously. After a period of reaction, the effluent from the salt chamber is an organic solution or inorganic solution with a low salt concentration, the effluent from the acid chamber is an acid solution with a high concentration, and the effluent from the alkali chamber is an alkali solution with a high concentration, completing the desalination process of the high-concentration salt solution and generating corresponding acids and alkalis, thereby effectively removing sodium chloride from the glyphosate-containing saline wastewater. The method for treating glyphosate-containing saline wastewater has the advantages of high desalination efficiency, sustainable production, and cost savings, and has the potential for industrial application.

[0056] With the above-mentioned ideal embodiment of the present invention as inspiration, through the above-mentioned description content, relevant staff can make various changes and modifications without departing from the scope of the present invention. The technical scope of this invention is not limited to the contents in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater, characterized in that: The following steps are involved: (1) transporting the glyphosate-containing saline wastewater to an aeration tank for aeration, and then filtering the wastewater using a first microporous filter to obtain preliminarily treated glyphosate-containing saline wastewater; (2) conveying the glyphosate-containing saline wastewater preliminarily treated in step (1) to a fluidized crystallization bed for softening treatment, and then filtering it with a second microporous filter to obtain softened and de-hardened glyphosate-containing saline wastewater; (3) The glyphosate-containing saline wastewater softened and de-hardened in step (2) is transported to the salt chamber of a bipolar membrane electrodialysis device for desalination treatment. The bipolar membrane electrodialysis device is composed of two electrode chambers and an electrodialysis compartment sandwiched between the two electrode chambers. The electrodialysis compartment is composed of an acid chamber, an alkali chamber, and a salt chamber arranged in an interval of an anion exchange membrane, a bipolar membrane, and a cation exchange membrane. The electrode chamber is divided into an anode chamber and a cathode chamber. The glyphosate-containing saline wastewater softened and de-hardened is introduced into the salt chamber of the bipolar membrane electrodialysis device, and an electrolyte solution of a certain concentration is injected into the electrode chamber. The cathode and anode of the bipolar membrane electrodialysis device are respectively connected to the direct current. The negative electrode and the positive electrode of the DC power source are connected, and the current density of the DC electric field is controlled to be 10-40 mA / cm2 and the temperature is 15-40° C. The bipolar membrane electrodialysis equipment is started, and the chloride ions selectively pass through the anion exchange membrane under the action of the electric field to reach the acid chamber and combine with the hydrogen ions generated by the bipolar membrane to generate hydrochloric acid, and the sodium ions selectively pass through the cation exchange membrane under the action of the electric field to reach the alkali chamber and combine with the hydroxide ions generated by the bipolar membrane to generate sodium hydroxide. When the conductivity of the salt chamber is reduced to 10 ms / cm, the treatment of NaCl in the glyphosate-containing saline wastewater is completed, and the acid solution, alkali solution and salt solution are recovered; (4) The salt solution in step (3) is filtered through a homogeneous membrane to recover glyphosate, and the remaining solution is evaporated and crystallized to obtain a crystalline phosphate product.

2. The bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater according to claim 1, characterized in that: The pore size of the first microporous filter in step (1) is 1 to 50 μm.

3. The bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater according to claim 1, characterized in that: In the step (2), the crystallization nuclei in the fluidized crystallization bed include at least one of silica sand, granular calcite and quartz sand, and the particle size of the crystallization nuclei is 0.2-0.5 mm.

4. The bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater according to claim 1, characterized in that: The pore size of the second microporous filter in step (2) is 0.2-1 μm.

5. The bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater according to claim 1, characterized in that: The thickness of the anion exchange membrane in step (3) is 0.1 to 0.13 mm, and the surface resistance is 0.1 to 0.9 Ω / cm 2 , selective permeability is greater than 96%.

6. The bipolar membrane electrodialysis treatment method for glyphosate-containing saline wastewater according to claim 1, characterized in that: The thickness of the cation exchange membrane in step (3) is 0.08-0.1 mm, and the surface resistance is 0.5-3 Ω / cm 2 , selective permeability is greater than 98%.

7. The bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater according to claim 1, characterized in that: The bipolar membrane in step (3) has a thickness of 0.2 to 0.25 mm and a surface resistance of 0.5 to 2 Ω / cm 2 .

8. The bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater according to claim 1, characterized in that: In step (3), the electrolyte solution circulating in the electrode chamber is a sodium sulfate solution.

9. The bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater according to claim 1, characterized in that: In the step (3), the separators between the inner membranes of the bipolar membrane electrodialysis equipment are made of elastic, insulating and corrosion-resistant materials.

10. The bipolar membrane electrodialysis method for treating glyphosate-containing saline wastewater according to claim 1, characterized in that: The cathode and anode of the bipolar membrane electrodialysis device in step (3) are composed of a titanium-coated ruthenium anode and a stainless steel cathode.

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