Phosphorus and impurity removal system and process method for glyphosate waste salt

Abstract

The application discloses a phosphorus-removing and impurity-removing system and process method for glyphosate waste salt, which comprises a cleaning device, a catalytic oxidation device for catalytically oxidizing the preliminary purified salt obtained by the cleaning device, a membrane separation device in communication with the catalytic oxidation device, and a purified salt solution storage device, wherein the membrane separation device comprises an ultrafiltration device and a nanofiltration device in sequence; the phosphorus-removing and impurity-removing process comprises the following steps: adding a cleaning agent into the cleaning device, adding glyphosate waste salt into the cleaning device, cleaning for 0.5-1 h at 20-25 DEG C and drying, preparing a solution from the obtained preliminary purified salt, and stirring the solution with a modified carbon nanotube catalyst and an oxidant hydrogen peroxide in the catalytic oxidation device for 3-5 h to remove phosphorus and carbon, so as to obtain a purified salt solution; and the purified salt solution is subjected to ultrafiltration-nanofiltration reaction in sequence by the ultrafiltration device and the nanofiltration device, so as to obtain a refined salt solution which is stored in the purified salt storage device. The novel phosphorus-removing and impurity-removing system and process method for glyphosate waste salt can effectively solve the problem of high total carbon and total phosphorus in the glyphosate waste salt, and the system and process method are simple, low in cost and more suitable for industrial application.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of phosphorus removal and impurity removal process of glyphosate waste salt, and particularly relates to a phosphorus removal and impurity removal system and process method for glyphosate waste salt. BACKGROUND

[0002] Glyphosate is a highly efficient, non-selective herbicide. Currently, there are mainly two methods for industrial production of glyphosate, i.e., glycine method and imino diacetic acid method (IDA method). Taking the glycine method as an example, a large amount of NaCl is generated in the process of recovering solvent methanol and catalyst triethylamine.

[0003] Glyphosate waste salt contains organic material raw materials used in glyphosate production and by-products generated in the synthesis process, especially phosphorus-containing substances (inorganic phosphorus and organic phosphorus), which cannot be directly used in industrial production, thereby seriously restricting the development of the glyphosate industry. A large amount of by-product salt is generated in the glyphosate production process, about one ton of by-product salt is generated per ton of glyphosate. The recycling of glyphosate waste salt has become one of the key problems for reducing production costs.

[0004] The prior art discloses a variety of treatment processes for glyphosate waste salt. For example, the invention patent with the application number 202111183335.8 and the name "Glyphosate by-product high-salt waste salt phosphorus removal and impurity removal system and process" discloses a glyphosate by-product salt phosphorus removal and impurity removal system including oxidation calcination, ultrafiltration nanofiltration, chemical precipitation, and adsorption phosphorus removal, which can make the total phosphorus content of the purified brine below 0.25 mg / L, and the total phosphorus content in the purified salt below 0.6 mg / kg. However, the process flow is complicated, and the calcination cost is high. For example, the invention patent with the application number 201610476692.6 and the name "Multi-stage resource recycling process for glyphosate mother liquor" discloses an effective combination of membrane separation, twice oxidation, three times crystallization separation, and normal temperature oxidation, which is a recycling process for glyphosate alkali mother liquor after triethylamine recovery device, can realize standard discharge; the membrane treatment device is combined with the concentration and refining unit, and after refining (TOC≤200 ppm), it meets the requirements of caustic soda production, realizes multi-stage resource recycling and reuse, reduces the discharge of three wastes and energy consumption, and is conducive to cost control.

[0005] Therefore, the present application provides a novel glyphosate waste salt phosphorus removal and impurity removal process, which is simple in process, high in phosphorus removal and impurity removal rate, low in cost, and more suitable for industrialized implementation of the phosphorus removal and impurity removal system and process method. SUMMARY

[0006] The technical problem to be solved by the application is to provide a system and process method which can effectively improve the TOC and TP removal efficiency, and are simple in system and process method, low in cost, and more suitable for industrial application.

[0007] Technical solution: The system is used for removing phosphorus and impurities from glyphosate waste salt, and comprises a cleaning device, a catalytic oxidation device for catalytic oxidation of the preliminary purified salt obtained by the cleaning device, a membrane separation device connected with the catalytic oxidation device, and a purified salt solution storage device.

[0008] Further, the top end of the cleaning device of the system is respectively provided with a glyphosate waste salt feeding port and a cleaning agent feeding port, the bottom end of the cleaning device is provided with a preliminary purified salt discharging port, the top end of the catalytic oxidation device is provided with a preliminary purified salt solution feeding port, the top end of the catalytic oxidation device is also respectively provided with a catalyst feeding port and an oxidizing agent discharging port, the bottom end of the catalytic oxidation device is connected with the liquid inlet of the ultrafiltration device, the liquid outlet of the ultrafiltration device is connected with the liquid inlet of the nanofiltration device, and the liquid outlet of the nanofiltration device is connected with the purified salt solution storage device to obtain the final purified salt solution.

[0009] The process method for removing phosphorus and impurities based on the above-mentioned system comprises the following steps: after adding a cleaning agent into the cleaning device, glyphosate waste salt is cleaned at 20-25 DEG C for 0.5-1 h and dried, the obtained preliminary purified salt is prepared into a solution and then enters the catalytic oxidation device, and is stirred with modified carbon nanotube catalyst and oxidizing agent hydrogen peroxide for 3-5 h to remove phosphorus and carbon, so as to obtain a purified salt solution; the purified salt solution is subjected to ultrafiltration-nanofiltration reaction in sequence through the ultrafiltration device and the nanofiltration device, so as to obtain a refined salt solution which is stored in the purified salt solution storage device.

[0010] Further, the cleaning agent used in the process method is ethylene glycol or acetone, and the mass ratio of glyphosate waste salt to cleaning agent is 1:1-3.

[0011] Further, the modified carbon nanotube used in the process method is prepared by the following steps: carbon nanotubes and modified materials are mixed at a mass ratio of 1:3-5, ultrasonic reaction is carried out at an ultrasonic frequency of 30-50 Hz for 20-40 min, the pH is adjusted to 6-8, and oil bath reaction is carried out at 70-90 DEG C for 6-12 h.

[0012] Further, the modified material used in the modified carbon nanotube is cerium chloride hexahydrate and iron chloride at a molar ratio of 1:0.5-2.

[0013] Further, the ultrafiltration membrane used in the process method has a molecular weight cut-off of 1000-2000 Da, and the nanofiltration membrane has a molecular weight cut-off of 300-600 Da.

[0014] Beneficial effects: Compared with the prior art, the significant advantages of the present invention are: the novel glyphosate waste salt phosphorus and impurity removal system and process can effectively solve the problems of high total carbon and total phosphorus in existing glyphosate waste salt and difficulty in treatment, and the system and process are simple, low in cost, and more suitable for industrial applications. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the phosphorus and impurity removal system of the present invention. Detailed Implementation

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0017] The phosphorus removal and impurity removal system of the present invention, such as Figure 1 As shown, the invention includes a cleaning device 1 with a glyphosate waste salt inlet and a cleaning agent inlet at its top, and a preliminary purified salt outlet at its bottom; a catalytic oxidation device 2 with a preliminary purified salt solution inlet, a catalyst inlet, and a cleaning agent inlet at its top, and a purified salt solution outlet at its bottom; an ultrafiltration device 4 connected to the purified salt solution outlet of the catalytic oxidation device 2 via an inlet, and an outlet on the other side of the ultrafiltration device 4; and a nanofiltration device 5 connected to the outlet of the ultrafiltration device 4 via an inlet, and an outlet on the other side of the nanofiltration device 5 connected to a purified salt solution storage device 3. The cleaning device 1 and the catalytic oxidation device 2 of this invention can be tanks commonly known in the art, with corresponding inlets at their top and bottom.

[0018] Based on the above phosphorus removal and impurity removal system, the process method for phosphorus removal and impurity removal of the present invention includes the following steps;

[0019] (1) After adding ethylene glycol or acetone cleaning agent into the cleaning device 1, glyphosate waste salt is added at a mass ratio of 1:1-3 to the cleaning agent. After cleaning at 20-25℃ for 0.5-1h, the glyphosate waste salt is dried to obtain preliminary purified salt.

[0020] (2) After preparing the preliminary purified salt into a preliminary purified salt solution with a concentration of 200-250 g / L, adjust the pH to 3.2, add it into the catalytic oxidation device 2, and stir and react with excess catalyst-modified carbon nanotubes and oxidant hydrogen peroxide for 3-5 hours to remove phosphorus and carbon, and obtain a purified salt solution.

[0021] (3) Adjust the pH of the purified salt solution to 7, and then pass it through an ultrafiltration device 4 with a molecular weight cutoff of 1000-2000 Da and a nanofiltration device 5 with a molecular weight cutoff of 300-600 Da in sequence to carry out an ultrafiltration-nanofiltration reaction to obtain a refined salt solution, which is then stored in a purified salt solution storage device 3.

[0022] The phosphorus and impurity removal process of the present application comprises the following steps:

[0023] Example 1

[0024] The phosphorus and impurity removal process of the present application comprises the following steps:

[0025] (1) Washing: 400 g of glyphosate waste salt was taken and added into a washing tank containing 800 g of acetone aqueous solution, stirred for 0.5 h, and centrifuged for 20 min by a centrifuge to obtain preliminary purified salt;

[0026] (2) Catalytic oxidation: carbon nanotubes and modified materials (molar ratio of 1:1 of cerium chloride hexahydrate and iron chloride) were mixed at a mass ratio of 1:4, ultrasonic reaction was carried out at an ultrasonic frequency of 40 Hz for 30 min, the pH was adjusted to 6-8, and oil bath reaction was carried out at 80°C for 10 h to prepare modified carbon nanotubes; the preliminary purified salt was prepared into a preliminary purified salt solution with a concentration of 220 g / L, the pH was adjusted to 3.2, excess modified carbon nanotubes and hydrogen peroxide were added and stirred for 4 h, the pH was adjusted to 7, and the purified salt solution was obtained by filtration.

[0027] (3) Membrane separation: the purified salt was subjected to membrane filtration treatment by using an ultrafiltration membrane with a membrane flux of 1000 Da and a nanofiltration membrane with a membrane flux of 300 Da.

[0028] The TP and TOC removal effects of this example are shown in Table 1.

[0029] Table 1 TP and TOC removal effects after washing-catalytic oxidation-membrane separation of Example 1

[0030]

[0031] As shown in Table 1, when the washing agent is acetone washing agent, after washing-catalytic oxidation-membrane separation, the TOC is 2.07 mg / L and the final TP is 0.095 mg / L.

[0032] Example 2

[0033] The phosphorus and impurity removal process of the present application comprises the following steps:

[0034] (1) Washing: 400 g of glyphosate waste salt was taken and added into a washing tank containing 800 g of acetone aqueous solution, stirred for 0.5 h, and centrifuged for 20 min by a centrifuge to obtain preliminary purified salt;

[0035] (2) Catalytic oxidation: the carbon nanotubes were mixed with modified materials (molar ratio of 1:1.5 of cerium chloride hexahydrate and iron chloride) at a mass ratio of 1:3.5, then ultrasonic reaction was carried out at an ultrasonic frequency of 35 Hz for 35 min, then the pH was adjusted to 6-8, and oil bath reaction was carried out at 75°C for 11 h to obtain modified carbon nanotubes; the preliminary purified salt solution was prepared to 230 g / L, the pH was adjusted to 3.2, then excess modified carbon nanotubes and hydrogen peroxide were added and stirred for 3.5 h, then the pH was adjusted to 7, and the purified salt solution was obtained by filtration.

[0036] (3) Membrane separation: the purified salt was subjected to membrane filtration treatment by using an ultrafiltration membrane with a membrane flux of 1000 Da and a nanofiltration membrane with a membrane flux of 600 Da.

[0037] The TP and TOC removal effects of Example 2 are shown in Table 2.

[0038] Table 2 TP and TOC removal effects after cleaning-catalytic oxidation-membrane separation of Example 2

[0039]

[0040] As shown in Table 2, when the cleaning agent is ethylene glycol cleaning agent, after cleaning-catalytic oxidation-membrane separation, the TOC is 1.52 mg / L, and the final TP is 1.66 mg / L.

[0041] Example 3

[0042] The phosphorus removal and impurity removal process of this example 3 includes the following steps:

[0043] (1) Cleaning: 300 g of glyphosate waste salt was taken into a cleaning tank, 600 g of acetone aqueous solution was added, stirred for 0.5 h, and then centrifuged for 10 min by a centrifuge to obtain preliminary purified salt.

[0044] (2) Catalytic oxidation: the carbon nanotubes were mixed with modified materials (molar ratio of 1:0.5 of cerium chloride hexahydrate and iron chloride) at a mass ratio of 1:3, then ultrasonic reaction was carried out at an ultrasonic frequency of 30 Hz for 40 min, then the pH was adjusted to 6-8, and oil bath reaction was carried out at 70°C for 12 h to obtain modified carbon nanotubes; the preliminary purified salt solution was prepared to 200 g / L, the pH was adjusted to 3.2, then excess modified carbon nanotubes and hydrogen peroxide were added and stirred for 3 h, then the pH was adjusted to 7, and the purified salt solution was obtained by filtration.

[0045] (3) Membrane separation: the purified salt was subjected to membrane filtration treatment by using an ultrafiltration membrane with a membrane flux of 1000 Da and a nanofiltration membrane with a membrane flux of 600 Da.

[0046] The TP and TOC removal effects of Example 3 are shown in Table 3.

[0047] Table 3 TP, TOC removal effect after cleaning-catalytic oxidation-membrane separation of Example 3

[0048]

[0049]

[0050] As shown in Table 3, when the cleaning agent is acetone cleaning agent, after cleaning-catalytic oxidation-membrane separation, TOC is 2.997 mg / L, and final TP is 0.113 mg / L.

[0051] Example 4

[0052] The phosphorus and impurity removal process of this example 4 includes the following steps:

[0053] (1) Cleaning: Take 500 g of glyphosate waste salt, add 1000 g of ethylene glycol aqueous solution into the cleaning tank, stir for 1 h, centrifuge for 30 min with a centrifuge, and obtain the preliminary purified salt;

[0054] (2) Catalytic oxidation: mix carbon nanotubes and modified material (molar ratio of cerium chloride hexahydrate to iron chloride is 1:2) according to a mass ratio of 1:5, ultrasonic reaction for 20 min under the condition of ultrasonic frequency of 50 Hz, adjust the pH to 6-8, oil bath reaction for 6 h at 90℃, and prepare modified carbon nanotubes; prepare a 250 g / L preliminary purified salt solution, adjust the pH to 3.2, add excess modified carbon nanotubes and hydrogen peroxide, stir for 5 h, adjust the pH to 7, and filter to obtain the purified salt solution.

[0055] (3) Membrane separation: use ultrafiltration membrane with a membrane flux of 1000 Da and nanofiltration membrane with a membrane flux of 600 Da to perform membrane filtration treatment on the purified salt.

[0056] The TP and TOC removal effect of this example 4 is shown in Table 3.

[0057] Table 4 TP, TOC removal effect after cleaning-catalytic oxidation-membrane separation of Example 4

[0058]

[0059] As shown in Table 4, when the cleaning agent is ethylene glycol cleaning agent, after cleaning-catalytic oxidation-membrane separation, TOC is 2.14 mg / L, and final TP is 1.94 mg / L.

[0060] As shown in the above examples, by using the system of the present application combined with the process of the present application, the TOC in the glyphosate waste salt can be reduced to about 2 mg / L, and the TP can be reduced to about 1 mg / L, which can effectively improve the TOC and TP removal efficiency.

Claims

1. A process for removing phosphorus and impurities from glyphosate waste salt, characterized in that, The process includes the following steps: after adding cleaning agent to the cleaning device (1), glyphosate waste salt is added and cleaned at 20-25 ℃ for 0.5-1 h and dried. The obtained preliminary purified salt is then prepared into a solution and enters the catalytic oxidation device (2), where it is stirred and reacted with catalyst-modified carbon nanotubes and oxidant hydrogen peroxide for 3-5 h to remove phosphorus and carbon, thereby obtaining a purified salt solution. The purified salt solution is then subjected to an ultrafiltration device (4) and a nanofiltration device (5) for ultrafiltration-nanofiltration reaction to obtain a refined salt solution, which is then stored in the purified salt solution storage device (3). The modified carbon nanotubes are prepared by the following steps: carbon nanotubes and modifying materials are mixed at a mass ratio of 1:3-5, and then ultrasonically reacted at an ultrasonic frequency of 30-50 Hz for 20-40 min. After adjusting the pH to 6-8, the mixture is reacted in an oil bath at 70-90 ℃ for 6-12 h. The modifying materials are cerium chloride hexahydrate and ferric chloride in a molar ratio of 1:0.5-2.

2. The phosphorus and impurity removal process for glyphosate waste salt according to claim 1, characterized in that, The cleaning agent is ethylene glycol or acetone, and the mass ratio of glyphosate waste salt to the cleaning agent is 1:1-3.

3. The phosphorus and impurity removal process for glyphosate waste salt according to claim 1, characterized in that, Ultrafiltration membranes have a molecular weight cutoff of 1000-2000 Da, while nanofiltration membranes have a molecular weight cutoff of 300-600 Da.

4. A phosphorus and impurity removal system, characterized in that, The system is applied to the phosphorus and impurity removal process for glyphosate waste salt as described in any one of claims 1 to 3, comprising: a cleaning device (1), a catalytic oxidation device (2) for catalytic oxidation of the preliminary purified salt obtained by the cleaning device (1), a membrane separation device connected to the catalytic oxidation device (2), and a purified salt solution storage device (3), wherein the membrane separation device comprises an ultrafiltration device (4) and a nanofiltration device (5) connected in sequence.

5. The phosphorus removal and impurity removal system according to claim 4, characterized in that, The top of the cleaning device (1) is provided with a glyphosate waste salt inlet and a cleaning agent inlet, and the bottom of the cleaning device (1) is provided with a preliminary purified salt outlet. The top of the catalytic oxidation device (2) is provided with a preliminary purified salt solution inlet, and the top of the catalytic oxidation device (2) is also provided with a catalyst inlet and an oxidant outlet. The bottom of the catalytic oxidation device (2) is connected to the inlet of the ultrafiltration device (4), the outlet of the ultrafiltration device (4) is connected to the inlet of the nanofiltration device (5), and the outlet of the nanofiltration device (5) is connected to the purified salt solution storage device (3) to obtain the final purified salt solution.

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