Creatine monohydrate mother liquor treatment method and treatment system

Abstract

This invention belongs to the field of chemical technology, specifically relating to a method and system for treating creatine monohydrate mother liquor. First, the creatine monohydrate mother liquor undergoes a first resin adsorption process to adsorb sodium sarcosinate. Then, a second resin adsorption process is performed to adsorb cyanamide derivatives. Finally, sodium ions are separated using bipolar membrane electrodialysis. This "resin adsorption + bipolar membrane electrodialysis" technology significantly improves the absorption rate of sodium sarcosinate and cyanamide derivatives, while significantly reducing the wastewater discharge and the content of pollutants (COD, ammonia nitrogen) in the wastewater, making it environmentally friendly. The creatine monohydrate mother liquor treatment system disclosed in this application can efficiently recover and utilize organic matter and inorganic salts in the mother liquor, reducing wastewater discharge and possessing significant environmental value and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a method and system for treating creatine monohydrate mother liquor. Background Technology

[0002] Creatine monohydrate is a pharmaceutical raw material and health product additive. Currently, the mainstream production process for creatine monohydrate involves the condensation reaction of sodium sarcosinate and cyanamide. However, the resulting mother liquor contains unreacted sodium sarcosinate, cyanamide derivatives, sodium chloride, and trace byproducts. Traditional treatment methods rely on acid-base neutralization, which suffers from high pollution, low efficiency, and high cost. After neutralization, the mother liquor has a salt concentration as high as 15-20% (calculated as NaCl) and a COD ≥ 5000 mg / L. Direct discharge can easily lead to soil salinization and aquatic ecosystem toxicity. Furthermore, the recovery rate of the active ingredient is less than 60%, and waste liquor treatment costs account for more than 20% of the total production cost. Existing technologies also employ bipolar membrane electrodialysis to treat the mother liquor, but the waste liquor discharge volume is high, typically 1000 m³ / h. 3 The mother liquor will generate 500 m³ of waste liquid. With increasingly stringent environmental policies, the development of efficient and low-consumption mother liquor resource utilization technology has become an urgent need for the industry. Summary of the Invention

[0003] Based on this, this application provides a method and system for treating creatine monohydrate mother liquor, in order to solve the technical problems of large waste liquid discharge, easy soil salinization and water ecological toxicity caused by direct discharge, and insufficient recovery rate of effective components in the prior art.

[0004] The technical solution to the above-mentioned technical problems in this application is as follows: A method for treating creatine monohydrate mother liquor includes the following steps: S10. The creatine monohydrate mother liquor is subjected to a first resin adsorption process to adsorb sodium sarcosinate, resulting in a first mother liquor with a sodium sarcosinate content ≤0.6%. S20. The first mother liquor is subjected to a second resin adsorption to adsorb the monocyanamide derivative therein, so as to obtain a second mother liquor with the content of monocyanamide derivative in the second mother liquor being ≤1.3%; S30. The second mother liquor is separated and the sodium ions are removed by bipolar membrane electrodialysis to obtain HCl, NaOH and waste liquid; S40. The NaOH is recycled to the resin in step S20 for elution.

[0005] A creatine monohydrate mother liquor treatment system, employing the creatine monohydrate mother liquor treatment method described above, the creatine monohydrate mother liquor treatment system comprising: The first resin tower group is equipped with a first mother liquor discharge pipe; The second resin tower group is provided with a second mother liquor discharge pipe connected to the inlet of the second resin tower group. The bipolar membrane electrodialysis device has a second mother liquor outlet pipe connected to the inlet of the bipolar membrane electrodialysis device. The bipolar membrane electrodialysis device is equipped with a NaOH recovery pipe, an HCl outlet pipe, and a by-product outlet pipe. The NaOH recovery pipe is connected to the desorption inlet of the second resin tower group.

[0006] Compared with the prior art, this application has at least the following advantages: 1. The method for treating creatine monohydrate mother liquor disclosed in this application includes: S10. subjecting the creatine monohydrate mother liquor to a first resin adsorption to adsorb sodium sarcosinate, obtaining a first mother liquor with a sodium sarcosinate content ≤0.6%; S20. subjecting the first mother liquor to a second resin adsorption to adsorb cyanamide derivatives, obtaining a second mother liquor with a cyanamide derivative content ≤1.3%; S30. separating sodium ions from the second mother liquor using bipolar membrane electrodialysis to obtain HCl, NaOH, and waste liquid; S40. reusing the NaOH in step S20 to elute the resin. This "resin adsorption + bipolar membrane electrodialysis" technology significantly improves the absorption rate of sodium sarcosinate and cyanamide derivatives. Experiments show that the adsorption rate of sodium sarcosinate in the mother liquor can reach over 95%, and the average adsorption rate of cyanamide derivatives is 68%. In particular, when hydrogen peroxide is used to oxidize the first mother liquor, the adsorption rate of cyanamide derivatives is further improved, reaching 81%, demonstrating excellent adsorption performance.

[0007] 2. The method for treating creatine monohydrate mother liquor of this application can significantly reduce the discharge volume of waste liquid. Experiments show that it is significantly better than the existing technology (1000m³). 3 The mother liquor, which would otherwise generate 500 m³ of waste liquid, was reduced by 350 m³, resulting in a 70% reduction in waste liquid discharge. The COD content decreased from an average of 50 mg / g to 25 mg / g, a reduction rate of 50%. The ammonia nitrogen content decreased from an average of 10 mg / g to 4.15 mg / g, a reduction rate of 58.5%. Therefore, the technical solution presented in this application, in treating creatine monohydrate mother liquor, not only effectively adsorbs sodium sarcosinate and cyanamide derivatives but also significantly reduces waste liquid discharge and lowers the content of pollutants (COD and ammonia nitrogen) in the waste liquid, making it environmentally friendly.

[0008] 3. The creatine monohydrate mother liquor treatment system disclosed in this application employs a first resin tower group to adsorb sodium sarcosinate from the mother liquor, a second resin tower group to adsorb cyanamide derivatives from the mother liquor, and a bipolar membrane electrodialysis device to decompose NaCl in the mother liquor into NaOH and HCl. The regenerated NaOH can be reused for resin desorption, and the HCl can be reused in the production process. This synergistic closed-loop process of "resin adsorption-bipolar membrane electrodialysis" can efficiently recover and utilize organic matter and inorganic salts in the mother liquor, reduce wastewater discharge, and has significant environmental value and economic benefits. Attached Figure Description

[0009] Figure 1 This is a system diagram of the creatine monohydrate mother liquor treatment system of this application.

[0010] In the diagram: First resin tower group 100, first anion exchange resin tower 110, second anion exchange resin tower 120, mother liquor feed pipe 130, first mother liquor discharge pipe 140, mother liquor transfer pump 141, mother liquor transfer tank 142, first desorption liquid tank 150, first desorption liquid feed pipe 160, first desorption liquid transfer tank 161, first desorption liquid transfer pump 162, first desorption liquid replenishment pipe 170, first check valve 171, first desorption liquid discharge pipe 180, first desorption liquid recovery tank 181, second desorption liquid feed pipe 190, second resin tower group 200, first cation exchange... Sub-resin tower 210, second cation resin tower 220, third desorption liquid feed pipe 230, second desorption liquid transfer tank 231, second desorption liquid transfer pump 232, second desorption liquid discharge pipe 240, second desorption liquid recovery tank 241, fourth desorption liquid feed pipe 250, second desorption liquid tank 260, second desorption liquid replenishment pipe 270, second check valve 271, second mother liquor discharge pipe 280, bipolar membrane electrodialysis device 300, alkali outlet 310, NaOH recovery pipe 320, HCl discharge pipe 330, concentrated water discharge pipe 340, post-treatment device 400. Detailed Implementation

[0011] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0012] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0014] In one specific embodiment of this application, a method for treating creatine monohydrate mother liquor includes the following steps: S10. The creatine monohydrate mother liquor undergoes a first resin adsorption process to adsorb sodium sarcosinate, yielding a first mother liquor with a sodium sarcosinate content ≤0.6%. Further, the first resin adsorption process includes passing the creatine monohydrate mother liquor through at least two anion exchange resin towers connected in series for adsorption. The creatine monohydrate mother liquor originates from the production process of creatine monohydrate. The creatine monohydrate solution obtained from the production system is cooled, crystallized, and separated to obtain a solid creatine monohydrate product and mother liquor. The mother liquor contains unreacted sodium sarcosinate, cyanamide derivatives, sodium chloride, and trace byproducts. In this step, sodium sarcosinate in the mother liquor is first adsorbed through a first resin adsorption process. For the adsorption of sodium sarcosinate, a macroporous weakly basic anion exchange resin is selected. Selective adsorption is achieved through the electrostatic interaction between the basic groups and sodium sarcosinate. To enhance the adsorption effect and increase the adsorption rate, it is preferable to pass the creatine monohydrate mother liquor through at least two anion exchange resin towers connected in series for adsorption, yielding the first mother liquor. In some cases, in order to achieve a higher adsorption rate of cyanamide derivatives in subsequent steps, the first mother liquor can be oxidized, for example by introducing hydrogen peroxide into the first mother liquor at a rate of 0.5 wt%.

[0015] S20. The first mother liquor is subjected to a second resin adsorption to adsorb the monocyanamide derivative therein, resulting in a second mother liquor with a monocyanamide derivative content ≤1.3%. Further, the second resin adsorption includes passing the first mother liquor through at least two cation exchange resin towers connected in series for adsorption. After the adsorption of sodium sarcosinate in the mother liquor in the previous step, the first mother liquor still contains monocyanamide derivatives, sodium chloride, and trace byproducts. At this point, the monocyanamide derivative needs to be adsorbed. In the second resin adsorption, an acidic cation exchange resin containing acidic groups is selected, which can adsorb the monocyanamide derivative. Similarly, to enhance the adsorption effect and increase the adsorption rate, it is preferable to pass the first mother liquor through at least two cation exchange resin towers connected in series for adsorption to obtain the second mother liquor.

[0016] S30. The second mother liquor is separated from sodium ions using bipolar membrane electrodialysis to obtain HCl, NaOH, and byproducts. The second mother liquor also contains sodium chloride; in this step, the sodium chloride is separated by bipolar membrane electrodialysis to decompose the NaCl in the second mother liquor into HCl and NaOH. Bipolar membrane electrodialysis (BPED) is an electrochemical separation process that utilizes the migration of ions under a direct current electric field, widely used for separating charged and uncharged media. Under a direct current electric field, bipolar membrane electrodialysis utilizes the selective permeability of anion and cation exchange membranes to separate ionic solutes and solvents in a solution. It is a physicochemical process that can convert salts in aqueous solutions into corresponding acids and bases without introducing new components. The HCl separated by bipolar membrane electrodialysis can be reused in production processes; NaOH can be used as a desorption solution to elute and regenerate resins, extending their lifespan, while effectively reusing the mother liquor and saving raw materials.

[0017] S40. The NaOH is recycled to the resin in step S20 for elution.

[0018] In a preferred embodiment, the elution process further includes eluting the anion exchange resin column with a first desorption solution, wherein the first desorption solution is a 30% to 80% isopropanol solution and a 1% to 5% NaOH solution, the desorption temperature is 20 to 50°C, and the flow rate of the first desorption solution is 0.5 to 2 BV / h; and eluting the cation exchange resin column with a second desorption solution, wherein the second desorption solution is a 30% to 80% isopropanol solution and a 1% to 5% NaOH solution, the desorption temperature is 20 to 50°C, and the flow rate of the second desorption solution is 0.5 to 2 BV / h. In this application, both the anion exchange resin column and the cation exchange resin column are eluted using a gradient elution system, namely an "isopropanol-dilute NaOH" gradient elution system, combined with dynamic elution (flow rate 2 BV / h, temperature 40°C), which can achieve a desorption rate ≥95% and increase the resin cycle life to ≥60 cycles.

[0019] It is worth noting that the process temperature and process time involved in the above embodiments are all temperatures or times used in the experiment. Any reasonable adjustments made by those skilled in the art based on the process temperature and process time provided by the present invention, within the error range, should be included within the protection scope of the present invention.

[0020] The following specific experimental examples further illustrate the technical solution and technical effects of the present invention.

[0021] It should be noted that in the embodiments of the present invention, all raw materials and reagents are commercially available and can be used without further purification.

[0022] Bipolar membrane electrodialysis device: Shandong Tianwei Membrane Technology Co., Ltd., TWEDBM-8-20S, acid-base conversion capacity 12mol / hr; COD meter: 10~5000mg / L COD, Dalian Xindongxing Instrument Co., Ltd.; Ammonia nitrogen meter: 0~500mg / L, Dalian Xindongxing Instrument Co., Ltd.; Anion exchange resin: NDA-99, Hebei Langfang Electric Power Resin Co., Ltd.; Cationic resin: XAD-4, Hebei Langfang Electric Power Resin Co., Ltd.; Mother liquor properties: sodium sarcosinate content 12%, cyanamide derivative content 4%, COD content 50mg / g, ammonia nitrogen content 10mg / g.

[0023] 1. Experimental Example 1 1000m 3 The mother liquor is first fed into two anion exchange resin towers connected in series for adsorption to obtain the first mother liquor, and the content of sodium sarcosinate in the first mother liquor is detected. Then, the first mother liquor is fed into two cation exchange resin towers connected in series for adsorption to obtain the second mother liquor, and the content of cyanamide derivatives in the second mother liquor is detected. The second mother liquor is then fed into a bipolar membrane electrodialysis device for treatment, and the resulting waste liquid is collected and the content of pollutants in the waste liquid is detected.

[0024] 2. Experimental Example 2 1000m 3 The mother liquor is first fed into two anion exchange resin towers connected in series for adsorption to obtain the first mother liquor, and the sodium sarcosinate content in the first mother liquor is measured. Then, hydrogen peroxide is passed through the first mother liquor for oxidation, with the amount of hydrogen peroxide introduced being 0.5 wt% of the first mother liquor. The oxidized first mother liquor is then fed into two cation exchange resin towers connected in series for adsorption to obtain the second mother liquor, and the cyanamide derivative content in the second mother liquor is measured. The second mother liquor is then sent to a bipolar membrane electrodialysis device for treatment, and the resulting waste liquid is collected and the pollutant content in the waste liquid is measured.

[0025] The pollutant content in the above-mentioned waste liquid was tested, and the results are as follows: Table 1. Detection results of pollutants in waste liquid

[0026] As can be seen from the table above, the "resin adsorption + bipolar membrane electrodialysis" technology of this application can achieve an adsorption rate of over 95% for sodium sarcosinate in the mother liquor and an average adsorption rate of 68% for cyanamide derivatives. Simultaneously, the waste liquid discharge is significantly reduced compared to existing technologies (1000m³ / day). 3 The mother liquor, which would otherwise produce 500 m³ of waste liquid, was reduced by 350 m³, resulting in a 70% reduction in waste liquid discharge. The COD content decreased from an average of 50 mg / g to 25 mg / g, a reduction rate of 50%. The ammonia nitrogen content decreased from an average of 10 mg / g to 4.15 mg / g, a reduction rate of 58.5%. Therefore, the technical solution of this application, in treating creatine monohydrate mother liquor, not only effectively adsorbs sodium sarcosinate and cyanamide derivatives but also significantly reduces waste liquid discharge and the content of pollutants (COD and ammonia nitrogen) in the waste liquid, making it environmentally friendly. In particular, in Experiment 2, the use of hydrogen peroxide to oxidize the first mother liquor further improved the adsorption rate of cyanamide derivatives, reaching 81%, demonstrating excellent adsorption performance.

[0027] In another specific embodiment of this application, a creatine monohydrate mother liquor treatment system includes: a first resin tower group 100, the first resin tower group 100 being provided with a first mother liquor outlet pipe 140; a second resin tower group 200, the first mother liquor outlet pipe 140 being connected to the inlet of the second resin tower group 200, the second resin tower group 200 being provided with a second mother liquor outlet pipe 280; and a bipolar membrane electrodialysis device 300, the second mother liquor outlet pipe 280 being connected to the inlet of the bipolar membrane electrodialysis device 300, the bipolar membrane electrodialysis device 300 being provided with a NaOH recovery pipe 320, an HCl outlet pipe and a concentrated water outlet pipe 340, the NaOH recovery pipe 320 being connected to the inlet of a second desorption liquid tank 260.

[0028] The creatine monohydrate solution produced by the creatine monohydrate production system is cooled, crystallized, and separated to obtain solid creatine monohydrate product and mother liquor. The mother liquor contains unreacted sodium sarcosinate, cyanamide derivatives, sodium chloride, and trace byproducts. The mother liquor is conveyed to the first resin tower group 100, where sodium sarcosinate is adsorbed. At this point, the mother liquor still contains cyanamide derivatives, sodium chloride, and trace byproducts. This portion of the mother liquor is conveyed to the second resin tower group 200 through the first mother liquor outlet pipe 140. The second resin tower group 200 adsorbs cyanamide derivatives from the mother liquor. The mother liquor discharged through the second mother liquor outlet pipe 280, containing sodium chloride and trace byproducts, then passes through a bipolar membrane electrodialysis unit 300 to decompose the NaCl into NaOH and HCl. The HCl is then decomposed into NaOH and HCl by HCl exchange. The alkali solution is discharged through the outlet pipe and can be used in production. The NaOH recovery pipe 320 is connected to the alkali outlet 310 mentioned above, which is connected to the desorption inlet of the second resin tower group 200. That is, the alkali outlet 310 is connected to the second desorption liquid tank 260 through the NaOH recovery pipe 320. NaOH is transported to the second desorption liquid tank 260 through the NaOH recovery pipe 320 as a supplement to the desorption liquid for resin desorption. At this time, only a small amount of waste liquid is discharged through the concentrate outlet pipe 340, which greatly reduces the risk of environmental pollution. This "resin adsorption-bipolar membrane electrodialysis" synergistic closed-loop circulation process can efficiently recover and utilize organic matter and inorganic salts in the mother liquor, reduce wastewater discharge, and has significant environmental value and economic benefits.

[0029] Furthermore, the first resin tower group 100 includes a first anion resin tower 110 and a second anion resin tower 120 connected in series. The inlet of the first anion resin tower 110 is provided with a mother liquor feed pipe 130, the outlet of the first anion resin tower 110 is connected to the inlet of the second anion resin tower 120, and the outlet of the second anion resin tower 120 is provided with a first mother liquor discharge pipe 140.

[0030] Both the first anion exchange resin tower 110 and the second anion exchange resin tower 120 of this application use macroporous basic anion exchange resins containing basic groups, which can selectively adsorb sodium sarcosinate through electrostatic interaction. Examples include resins such as D301, NDA-99, NDA-88, NDA-900, and NDA-55 (produced by Jiangsu Nanda Gode Environmental Protection Technology Co., Ltd., Hebei Langfang Electric Power Resin Co., Ltd., etc.). Specific resin models are not limited here and can be selected according to actual conditions. After adsorption in the first anion exchange resin tower 110 via the mother liquor feed pipe 130, the mother liquor is sent to the second anion exchange resin tower 120 for secondary adsorption, which can enhance the adsorption effect and improve the adsorption rate.

[0031] After adsorption in the first resin tower group 100, the mother liquor is then transported to the second resin tower group 200 via the first mother liquor discharge pipe 140. Preferably, the first mother liquor discharge pipe 140 is equipped with a mother liquor transfer pump 141 and a mother liquor transfer tank 142 sequentially along the discharge direction. The mother liquor transfer pump 141 is used to transport the mother liquor after adsorption in the first resin tower group 100 to the second resin tower group 200, and the mother liquor transfer tank 142 is used to temporarily store and transfer this portion of the mother liquor to adapt to intermittent or continuous production.

[0032] After the first resin tower group 100 adsorbs sodium sarcosinate from the mother liquor, it needs to be eluted with desorption liquid for further processing and recovery of sodium sarcosinate, and to regenerate the resin for reuse. Therefore, in a preferred embodiment, the above-mentioned creatine monohydrate mother liquor treatment system further includes a first desorption liquid tank 150. The first anion exchange resin tower 110 is provided with a first desorption liquid inlet pipe 160 and a first desorption liquid outlet pipe 180. The second anion exchange resin tower 120 is provided with a second desorption liquid inlet pipe 190. The first desorption liquid outlet pipe 180 is connected to a first desorption liquid recovery tank 181. The first desorption liquid inlet pipe 160 is connected to the desorption outlet at the bottom of the second anion exchange resin tower 120. The second desorption liquid inlet pipe 190 is connected to the first desorption liquid tank 150. The first desorption liquid tank 150 is used to hold the desorption liquid. The composition of the desorption liquid is selected according to the actual situation. The desorption liquid enters the second anion exchange resin tower 120 through the second desorption liquid feed pipe 190 to wash the resin in the second anion exchange resin tower 120. Then, it enters the first anion exchange resin tower 110 through the first desorption liquid feed pipe 160 to wash the resin in the first anion exchange resin tower 110. The washed liquid is discharged to the first desorption liquid recovery tank 181 through the first desorption liquid discharge pipe 180.

[0033] Furthermore, a first desorption liquid transfer tank 161 and a first desorption liquid transfer pump 162 are sequentially arranged on the first desorption liquid feed pipe 160 along the feed direction. A first desorption liquid replenishment pipe 170 is provided at the outlet of the first desorption liquid tank 150. The other end of the first desorption liquid replenishment pipe 170 is connected to the first desorption liquid transfer tank 161. A first check valve 171 is provided on the first desorption liquid replenishment pipe 170.

[0034] After elution in the second anion exchange resin tower 120, the desorption solution is transported to the first desorption solution transfer tank 161. The first desorption solution transfer tank 161 primarily serves as a temporary storage and transfer tank. The first desorption solution transfer pump 162 then transports the liquid from the first desorption solution transfer tank 161 to the first anion exchange resin tower 110 for resin elution. Since some desorption solution is consumed after elution in the second anion exchange resin tower 120, a first desorption solution replenishment pipe 170 is provided between the first desorption solution tank 150 and the first desorption solution transfer tank 161. This allows for direct replenishment of desorption solution from the first desorption solution tank 150 to the first desorption solution transfer tank 161, ensuring sufficient desorption in the first anion exchange resin tower 110. Simultaneously, a first check valve 171 installed on the first desorption solution replenishment pipe 170 prevents backflow of the desorption solution within the pipe.

[0035] In another specific embodiment of this application, the second resin tower group 200 includes a first cation resin tower 210 and a second cation resin tower 220 connected in series. The inlet of the first cation resin tower 210 is connected to the first mother liquor outlet pipe 140, the outlet of the first cation resin tower 210 is connected to the bottom desorption outlet of the second cation resin tower 220, and the outlet of the second cation resin tower 220 is provided with a second mother liquor outlet pipe 280.

[0036] The first cation exchange resin tower 210 and the second cation exchange resin tower 220 of this application use acidic cation exchange resins containing acidic groups, which can adsorb monocyanamide derivatives, such as XAD-4, NDA-150, JX-101, and NDA-110 resins (produced by Jiangsu Nanda Gode Environmental Protection Technology Co., Ltd., Hebei Langfang Electric Power Resin Co., Ltd., etc.). Specific resin models are not limited here and can be selected according to actual conditions. The mother liquor after adsorption in the first resin tower group 100 is sent through the first mother liquor outlet pipe 140 to the first cation exchange resin tower for adsorption of the monocyanamide derivatives therein, and then sent to the second anion exchange resin tower 120 for secondary adsorption, which can enhance the adsorption effect and improve the adsorption rate.

[0037] After the second resin tower group 200 adsorbs the monocyanamide derivative in the mother liquor, it needs to be eluted with a desorption liquid. Therefore, in a preferred embodiment, the above-mentioned creatine monohydrate mother liquor treatment system further includes a second desorption liquid tank 260. The first cation resin tower 210 is provided with a third desorption liquid inlet pipe 230 and a second desorption liquid outlet pipe. The second cation resin tower 220 is provided with a fourth desorption liquid inlet pipe 250. The second desorption liquid outlet pipe is connected to a second desorption liquid recovery tank. The third desorption liquid inlet pipe 230 is connected to the second cation resin tower 220, and the fourth desorption liquid inlet pipe 250 is connected to the second desorption liquid tank 260. The second desorption liquid tank 260 is used to hold the desorption liquid. The composition of the desorption liquid is selected according to the actual situation. The desorption liquid enters the second cation resin tower 220 through the fourth desorption liquid feed pipe 250 to wash the resin in the second cation resin tower 220. Then, it enters the first cation resin tower 210 through the third desorption liquid feed pipe 230 to wash the resin in the first cation resin tower 210. The washed liquid is discharged to the second desorption liquid recovery tank through the second desorption liquid discharge pipe.

[0038] Furthermore, the third desorption liquid feed pipe 230 is provided with a second desorption liquid transfer tank 231 and a second desorption liquid transfer pump in sequence along the feeding direction. The outlet of the second desorption liquid tank 260 is provided with a second desorption liquid replenishment pipe 270. The other end of the second desorption liquid replenishment pipe 270 is connected to the second desorption liquid transfer tank 231. The second desorption liquid replenishment pipe 270 is provided with a second check valve 271.

[0039] After elution in the second cation exchange resin tower 220, the desorption solution is transported to the second desorption solution transfer tank 231. The second desorption solution transfer tank 231 primarily serves as a temporary storage and transfer tank. A second desorption solution transfer pump then transports the liquid from the second desorption solution transfer tank 231 to the first cation exchange resin tower 210 for resin elution. Since some desorption solution is consumed after elution in the second cation exchange resin tower 220, a second desorption solution replenishment pipe 270 is installed between the second desorption solution tank 260 and the second desorption solution transfer tank 231. This allows for direct replenishment of desorption solution from the second desorption solution tank 260 to the second desorption solution transfer tank 231, ensuring sufficient desorption from the first cation exchange resin tower 210. Simultaneously, a second check valve 271 installed on the second desorption solution replenishment pipe 270 prevents backflow of the desorption solution within the pipe.

[0040] In another specific embodiment of this application, the second desorption liquid recovery tank is connected to a post-processing device 400. The post-processing device 400 is used to process the mixture in the second desorption liquid recovery tank, such as separation, purification and crystallization, resource recycling and environmental protection treatment. Similarly, the first desorption liquid recovery tank 181 can also be connected to the post-processing device 400 for processing the mixture in the first desorption liquid recovery tank 181.

[0041] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for treating creatine monohydrate mother liquor, characterized in that, Includes the following steps: S10. The creatine monohydrate mother liquor is subjected to a first resin adsorption process to adsorb sodium sarcosinate, resulting in a first mother liquor with a sodium sarcosinate content ≤0.6%. S20. The first mother liquor is subjected to a second resin adsorption to adsorb the monocyanamide derivative therein, so as to obtain a second mother liquor with a monocyanamide derivative content ≤1.3%; S30. The second mother liquor is separated from sodium ions by bipolar membrane electrodialysis technology to obtain HCl, NaOH and waste liquid; S40. The NaOH is recycled to the resin in step S20 for elution.

2. The method for treating creatine monohydrate mother liquor as described in claim 1, characterized in that, In step S10, the first resin adsorption includes adsorbing the creatine monohydrate mother liquor through at least two anion exchange resin towers connected in series.

3. The method for treating creatine monohydrate mother liquor as described in claim 2, characterized in that, It also includes eluting the anion exchange resin tower with a first desorption solution comprising: 30% to 80% isopropanol solution and 1% to 5% NaOH solution, the desorption temperature being 20 to 50°C, and the flow rate of the first desorption solution being 0.5 to 2 BV / h.

4. The method for treating creatine monohydrate mother liquor as described in claim 1, characterized in that, In step S20, the second resin adsorption includes adsorbing the first mother liquor through at least two cation exchange resin towers connected in series.

5. The method for treating creatine monohydrate mother liquor as described in claim 4, characterized in that, It also includes eluting the cation exchange resin column with a second desorption solution comprising: 30% to 80% isopropanol solution and 1% to 5% NaOH solution, the desorption temperature being 20 to 50°C, and the flow rate of the second desorption solution being 0.5 to 2 BV / h.

6. A creatine monohydrate mother liquor treatment system, employing the creatine monohydrate mother liquor treatment method as described in any one of claims 1 to 5, wherein the creatine monohydrate mother liquor treatment system comprises: The first resin tower group is equipped with a first mother liquor discharge pipe; The second resin tower group is provided with a second mother liquor discharge pipe connected to the inlet of the second resin tower group. The bipolar membrane electrodialysis device has a second mother liquor outlet pipe connected to the inlet of the bipolar membrane electrodialysis device. The bipolar membrane electrodialysis device is equipped with a NaOH recovery pipe, an HCl outlet pipe, and a by-product outlet pipe. The NaOH recovery pipe is connected to the desorption inlet of the second resin tower group.

7. The creatine monohydrate mother liquor treatment system as described in claim 6, characterized in that, The first resin tower group includes a first anion exchange resin tower and a second anion exchange resin tower connected in series. The inlet of the first anion exchange resin tower is provided with a mother liquor feed pipe, the outlet of the first anion exchange resin tower is connected to the inlet of the second anion exchange resin tower, and the outlet of the second anion exchange resin tower is provided with a first mother liquor discharge pipe.

8. The creatine monohydrate mother liquor treatment system as described in claim 7, characterized in that, It also includes a first desorption liquid tank, and the first anion exchange resin tower is equipped with a first desorption liquid inlet pipe and a first desorption liquid outlet pipe. The second anion exchange resin tower is provided with a second desorption liquid feed pipe, the first desorption liquid discharge pipe is connected to a first desorption liquid recovery tank, the first desorption liquid feed pipe is connected to the desorption outlet at the bottom of the second anion exchange resin tower, and the second desorption liquid feed pipe is connected to the first desorption liquid tank.

9. The creatine monohydrate mother liquor treatment system as described in claim 6, characterized in that, The second resin tower group includes a first cation resin tower and a second cation resin tower connected in series. The inlet of the first cation resin tower is connected to the first mother liquor outlet pipe, the outlet of the first cation resin tower is connected to the inlet of the second cation resin tower, and the outlet of the second cation resin tower is provided with a second mother liquor outlet pipe.

10. The creatine monohydrate mother liquor treatment system as described in claim 9, characterized in that, It also includes a second desorption liquid tank. The first cation exchange resin tower is provided with a third desorption liquid feed pipe and a second desorption liquid discharge pipe. The second cation exchange resin tower is provided with a fourth desorption liquid feed pipe. The second desorption liquid discharge pipe is connected to a second desorption liquid recovery tank. The third desorption liquid feed pipe is connected to the desorption outlet at the bottom of the second cation exchange resin tower. The fourth desorption liquid feed pipe is connected to the second desorption liquid tank.

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