Resourceful treatment process for preparing high-concentration acetonitrile waste liquid in chromatography field and application of resourceful treatment process

Abstract

The invention discloses a resourceful treatment process for preparing high-concentration acetonitrile waste liquid in the chromatography field and application, and belongs to the technical field of wastewater treatment in the environmental protection industry. The treatment process comprises the following steps: the waste liquid enters a solvent recovery unit after being subjected to pH regulation and filtration, and more than 99% of acetonitrile in the waste liquid is recovered into distillate; the residual liquid after the acetonitrile is recovered is treated by the deep treatment unit, so that the residual liquid can reach the sewage nanotube discharge standard, and the acetonitrile content is less than 0.5 mg / L. The solvent recovery unit consists of two stages of distillation systems, and the deep treatment unit takes a catalytic oxidation technology as a core. The whole process system not only realizes recycling of acetonitrile in the high-concentration acetonitrile waste liquid, but also realizes up-to-standard treatment of the residual liquid, and has good economic benefits and environmental benefits.

Description

Technical Field

[0001] The present application relates to a resource treatment process and application of high-concentration acetonitrile waste liquid in the field of preparative chromatography, and belongs to the technical field of wastewater treatment in the environmental protection industry. Background Art

[0002] Acetonitrile, with the chemical formula CH3CN, is a colorless, transparent liquid with the characteristics of high transparency, good solubility, and low UV background absorption. It has excellent solvent properties and is widely used in organic synthesis, medicine, textiles, analysis, etc. Acetonitrile is often used as a solvent in the field of preparative chromatography to separate and purify high-purity drugs, but it also produces a large amount of acetonitrile waste liquid.

[0003] The high-concentration acetonitrile waste liquid produced by preparative chromatography has a high water content and also contains a small amount of impurities such as inorganic salts, organic acids and proteins. It is difficult to treat and has strong environmental hazards. For high-concentration acetonitrile waste liquid, companies in the industry generally entrust professional hazardous waste treatment agencies to dispose of it, which is not only costly but also wastes resources; some companies in the industry use distillation to recover acetonitrile, which has problems such as high energy consumption and the need for further treatment of acetonitrile residual liquid. Hazardous waste treatment companies generally use incineration to treat high-concentration waste liquid. Incineration treatment consumes a lot of energy and there is a risk of secondary pollution such as nitrogen oxides and dioxins. Therefore, it is of great significance to develop economical and effective resource utilization and treatment processes for the high-concentration acetonitrile waste liquid currently generated in the field of preparative chromatography. Summary of the invention

[0004] In order to solve the above technical problems, this application proposes a general process idea and technical solution of "acetonitrile reuse + standard discharge" for high-concentration acetonitrile waste liquid generated in the field of preparative chromatography, which realizes the recycling of acetonitrile in acetonitrile waste liquid through two-stage distillation in the solvent recovery unit, and realizes the treatment and standard discharge of acetonitrile residual liquid through the deep treatment unit, and the insoluble matter in the acetonitrile waste liquid is discharged in the form of solid. A resource treatment process for high-concentration acetonitrile waste liquid in the field of preparative chromatography is formed, which realizes the reuse of acetonitrile in high-concentration acetonitrile waste liquid and the deep treatment of residual liquid, with low treatment cost and good effect.

[0005] This application adopts the following technical solutions: According to the first aspect of the present application, a resource recovery process for preparing high-concentration acetonitrile waste liquid in the chromatography field is provided, and the resource recovery process is carried out in a treatment system; The treatment system comprises a water inlet preparation unit, a filtration unit, a solvent recovery unit, a deep treatment unit, and a drainage preparation unit which are connected in sequence; Wherein, the solvent recovery unit includes a primary distillation system for separating acetonitrile recovery liquid and a secondary distillation system for separating acetonitrile residual liquid; The resource recovery process comprises the following steps: S1, passing the acetonitrile waste liquid into an inlet water preparation unit, and adjusting the pH value of the acetonitrile waste liquid to be neutral in the inlet water preparation unit; S2, passing the acetonitrile waste liquid after adjusting the pH value into a filtration unit, and filtering out suspended particles in the filtration unit; S3, passing the acetonitrile waste liquid from which suspended particles are filtered out into a solvent recovery unit, and performing two-stage distillation in the solvent recovery unit to obtain acetonitrile recovery liquid and acetonitrile residual liquid, respectively, and the acetonitrile recovery liquid is reused for production; S4, passing the acetonitrile residual liquid into a deep processing unit, and subjecting the acetonitrile residual liquid to catalytic oxidation treatment in the deep processing unit to obtain; S5. The acetonitrile residual liquid after catalytic oxidation treatment is passed into a drainage adjustment unit, and the pH is adjusted in the drainage adjustment unit to meet the discharge standards before being discharged.

[0006] Optionally, in step S3, the two-stage distillation process includes: the operating temperature of the primary distillation system is 50.0°C~99.5°C, more than 98% of the acetonitrile in the acetonitrile waste liquid is recovered into the distillate to obtain acetonitrile recovery liquid, and the kettle residue enters the secondary distillation system; the operating temperature of the secondary distillation system is 99.5°C~103°C, and the kettle residue obtained from the primary distillation system is further distilled to obtain acetonitrile residue. The above operating temperatures are the actual operating temperature range. During the distillation process, the distillate temperature will change as the fraction composition changes.

[0007] Optionally, in step S4, the volume of the acetonitrile recovery liquid is 39% to 44% of the acetonitrile waste liquid, and the volume of the acetonitrile residual liquid is 56% to 61% of the acetonitrile waste liquid.

[0008] Optionally, in step S4, the catalytic oxidation treatment method is selected from at least one of a catalytic hydrogen peroxide oxidation process, a catalytic ozone oxidation process and an electrocatalytic oxidation process.

[0009] Optionally, the conditions of the catalytic hydrogen peroxide oxidation process are: H2O2 dosage is mH2O2:mTOC=1~18, temperature is 40℃~120℃, pressure is 0~1.0MPa, and the volume space velocity of wastewater is 0.5h -1 ~6h -1 , the inlet water pH is 2~7.

[0010] Optionally, the conditions of the catalytic ozone oxidation process are: O3 dosage is mO3:mTOC=2.6~7.8, temperature is 30℃~50℃, volumetric space velocity of wastewater is 0.5h -1 ~6h -1 , the inlet water pH is 2~7.

[0011] Optionally, the conditions of the electrocatalytic oxidation process are: the amount of sodium chloride added is 0~2wt.%, the constant current is 1A~3A, the current density is 20mA / cm²~60mA / cm², the reaction is 2h~6h, the positive and negative electrodes are ruthenium titanium coated electrodes or sub-titanium oxide coated electrodes, and the inlet water pH is 2~7.

[0012] Optionally, in step S1, the TOC of the acetonitrile waste liquid is 70,000 mg / L to 160,000 mg / L; The acetonitrile concentration in the acetonitrile waste liquid is 120g / L~280g / L.

[0013] Optionally, in step S3, the TOC of the acetonitrile recovery liquid is 200,000 mg / L to 350,000 mg / L, and the acetonitrile concentration in the acetonitrile recovery liquid is 350 g / L to 600 g / L.

[0014] According to another aspect of the present application, a resource treatment process for high-concentration acetonitrile waste liquid in the field of preparative chromatography is provided for use in industrial recycling of high-concentration acetonitrile waste liquid, comprising the following process: conducting experiments on target high-concentration acetonitrile waste liquid through the resource treatment process to obtain and determine the required parameters of the treatment process; The industrial equipment is selected and customized according to the said parameters.

[0015] The beneficial effects of this application include: The resource processing process for high-concentration acetonitrile waste liquid in the field of preparative chromatography provided in the present application realizes the recovery of more than 99% of acetonitrile in high-concentration acetonitrile waste liquid through two-stage distillation; through deep treatment, the acetonitrile content in the residual liquid is reduced to less than 0.5 mg / L, and other indicators meet the emission requirements; the entire processing process realizes both the recovery and utilization of acetonitrile in high-concentration acetonitrile waste liquid and the standard treatment of the residual liquid, has good economic and environmental benefits, and no secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the process flow chart for resource treatment of high-concentration acetonitrile waste liquid for this application. DETAILED DESCRIPTION

[0017] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0018] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0019] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.

[0020] TOC (total organic carbon) uses TOC-V produced by Shimadzu Corporation of Japan CPH / CPN The analyzer is used for determination; pH was measured using a Lei-Magnetic PHS-3C precision pH meter; The acetonitrile content was determined by GC-2100 gas chromatograph equipped with FID detector and FFAP column (30 m×0.32 mm×0.25 μm) for detection, with injection port temperature of 200°C, carrier gas flow rate of 2.0 mL / min, injection volume of 1.0 μL, split ratio of 10:1, FID250°C, column temperature of 60°C maintained for 1 min, heating rate of 8°C / min, air flow rate of 450 mL / min, and air flow rate of 45 mL / min.

[0021] SS (suspended solids) is determined using the "GB 11901-89 Gravimetric method for determination of suspended solids in water quality".

[0022] The small-scale test equipment built in the laboratory was used to conduct experiments on the units of preparation, filtration, solvent recovery, and deep treatment. The small-scale test equipment involved can be built or commercially purchased or customized by technicians in the field according to the existing technology as needed, so as to achieve the following process conditions: the solvent recovery unit is composed of a two-stage distillation system, the operating temperature of the first-stage distillation system is 50.0℃~99.5℃, more than 98% of the acetonitrile in the acetonitrile waste liquid is recovered into the distillate to obtain acetonitrile recovery liquid, and the kettle residue enters the secondary distillation system; the operating temperature of the secondary distillation system is 99.5℃~103.0℃, and the kettle residue obtained from the first-stage distillation system is further distilled to obtain acetonitrile residue. The volume of acetonitrile recovery liquid is 39%~44% of the acetonitrile waste liquid, and the volume of acetonitrile residue is 56%~61% of the acetonitrile waste liquid. The deep treatment unit adopts catalytic oxidation process. The catalytic hydrogen peroxide oxidation conditions are H2O2 dosage of mH2O2:mTOC= 1~18, temperature 40℃~150℃, pressure 0~1.0MPa, and volume space velocity of wastewater: 0.5h -1 ~6h -1 The catalytic ozone oxidation conditions are: O3 dosage is m O3: m TOC = 2.6-7.8, temperature is 30-50°C, volumetric space velocity of wastewater is 0.5h -1 ~6h -1 The electrocatalytic conditions are as follows: the amount of sodium chloride added is 0-2wt.%, the constant current is 1A-3A, the current density is 20mA / cm²-60mA / cm², the reaction time is 2h-6h, and the positive and negative electrodes are ruthenium titanium coated electrodes or sub-titanium oxide coated electrodes.

[0023] The acetonitrile waste liquid used in the examples of this application was taken from the actual waste liquid produced by a preparative chromatography company. According to the difference in water quality, the samples were marked as sample 1, sample 2 and sample 3. The specific water quality is shown in Table 1: Table 1 Acetonitrile waste liquid

[0024] Example 1 System and process for recycling high-concentration acetonitrile waste liquid in the field of preparative chromatography High-concentration acetonitrile wastewater resource treatment system in the field of preparative chromatography Figure 1 As shown, the system includes a water inlet preparation unit, a filtration unit, a solvent recovery unit, a deep treatment unit, and a drainage preparation unit which are connected in sequence; The water inlet preparation unit is used to adjust the pH value of the acetonitrile waste liquid; The filtration unit is used to filter out the total suspended particles in the acetonitrile waste liquid, producing a small amount of solid residue; The solvent recovery and treatment unit is used to separate the acetonitrile waste liquid, and is specifically composed of a two-stage distillation system: the first-stage distillation system is used to recover more than 98% of the acetonitrile in the acetonitrile waste liquid into the distillate to obtain acetonitrile recovery liquid; the second-stage distillation system is used to continue to distill the kettle residual liquid obtained from the first-stage distillation system to obtain acetonitrile residual liquid. A small amount of solid residue is produced during the second-stage distillation process.

[0025] The deep treatment unit is used to treat acetonitrile waste liquid by using catalytic oxidation technology, and the catalytic oxidation technology adopts at least one of catalytic hydrogen peroxide oxidation process, catalytic ozone oxidation process and electrocatalytic oxidation process.

[0026] The drainage blending unit is used to adjust the pH value of the residual liquid after treatment in the deep treatment unit to meet the discharge standards.

[0027] The above system is used to realize the resource treatment process of high-concentration acetonitrile waste liquid in the field of preparative chromatography, such as Figure 1 As shown, the specific processing steps are as follows: (1) The acetonitrile waste liquid enters the water preparation unit, and the pH is adjusted to neutral with alkaline solution; (2) The pH-adjusted acetonitrile waste liquid enters the filtration unit, and the suspended particles are removed; (3) The filtered acetonitrile waste liquid enters the solvent recovery unit and is processed by a two-stage distillation system to obtain acetonitrile recovery liquid and acetonitrile residual liquid respectively; (4) The acetonitrile recovery liquid is reused in production, and the acetonitrile residual liquid enters the deep treatment unit to treat pollutants to below the emission limit value; (5) The acetonitrile recovery liquid after deep treatment enters the drainage preparation unit, and uses acid or alkali solution to adjust the pH to neutral to meet the direct discharge standard.

[0028] Using the above-mentioned high-concentration acetonitrile waste liquid resource treatment process in the field of preparative chromatography, the acetonitrile waste liquid samples in Table 1 were subjected to resource treatment processes respectively. The specific process steps and process conditions in each treatment unit and the effluent water quality results are as follows: (1) Dispensing unit The pH of the acetonitrile wastewater was adjusted to about 7.0 using liquid caustic soda and then transported to the filtration unit. The effluent quality is shown in Table 2.

[0029] Table 2

[0030] (2) Filtration unit The SS in the conditioned acetonitrile wastewater is removed by the filtration unit and then transported to the solvent recovery unit. The effluent quality is shown in Table 3.

[0031] Table 3

[0032] (3) Solvent recovery unit The solvent recovery unit adopts a two-stage distillation system. The operating temperature of the first-stage distillation system is 50.0℃~99.5℃. More than 98% of the acetonitrile in the acetonitrile waste liquid is recovered into the distillate to obtain acetonitrile recovery liquid, and the kettle residue enters the secondary distillation system; the operating temperature of the secondary distillation system is 99.5℃~103.0℃, and the kettle residue obtained from the first-stage distillation system is further distilled to obtain the distillate of acetonitrile residue. After testing, after samples 1~3 were treated by the solvent recovery unit, the volume of acetonitrile recovery liquid was 39%~44% of the acetonitrile waste liquid, and the volume of acetonitrile residue was 56%~61% of the acetonitrile waste liquid. The effluent quality is shown in Table 4 and Table 5.

[0033] Table 4 Acetonitrile recovery solution

[0034] Table 5 Acetonitrile Residue

[0035] (4) Depth processing unit ① When the deep treatment adopts the catalytic hydrogen peroxide oxidation process, the reaction conditions are: H2O2 dosage is m H2O2: mTOC = 6, temperature is 50℃, pressure is normal pressure, and the volumetric space velocity of wastewater is 1.0 h -1 The effluent quality is shown in Table 6.

[0036] Table 6

[0037] ② When the deep treatment adopts catalytic ozone oxidation process, the reaction conditions are: O3 dosage is m O3:m TOC =4.0, temperature is 40℃, volume space velocity of wastewater is 1.0 h -1 The effluent quality is shown in Table 7.

[0038] Table 7

[0039] ③ When the electrocatalytic oxidation process is used for deep treatment, the reaction conditions are: sodium chloride addition amount is 0.3wt.%, constant current is 2A, current density is 40mA / cm², reaction time is 3h, and the positive and negative electrodes are ruthenium titanium coated electrodes. The effluent water quality is shown in Table 8.

[0040] Table 8

[0041] ④ When the deep treatment adopts the combined process of catalytic hydrogen peroxide oxidation and catalytic ozone oxidation, the reaction conditions are: H2O2 dosage is m H2O2: m TOC = 3, O3 dosage is m O3: m TOC = 2.0, temperature is 40℃, volumetric space velocity of wastewater is 1.0 h -1 The effluent quality is shown in Table 9.

[0042] Table 9

[0043] ⑤ When the deep treatment adopts the combined process of catalytic hydrogen peroxide oxidation and electrocatalytic oxidation, the reaction conditions are: H2O2 dosage is m H2O2: m TOC = 3; sodium chloride addition is 0.3wt.%, constant current is 1A, current density is 20mA / cm², positive and negative electrodes are ruthenium titanium coated electrodes, temperature is 40℃, volume space velocity of wastewater is 1.0 h -1 The effluent quality is shown in Table 10.

[0044] Table 10

[0045] The resource recovery treatment process proposed in this application was used to conduct experiments on three actual acetonitrile waste liquids, sample 1, sample 2 and sample 3. The results showed that the process route developed in this application can not only realize the recovery of acetonitrile in acetonitrile waste liquid, but also the acetonitrile residual liquid can meet the discharge requirements after deep treatment. The treatment process is determined through the above experiments, and then the industrial equipment for the resource recovery treatment process of high-concentration acetonitrile waste liquid is selected and customized according to the process parameters.

[0046] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A resource treatment process for high-concentration acetonitrile waste liquid in the field of preparative chromatography, characterized in that: The resource recovery process is carried out in a processing system; The treatment system comprises a water inlet preparation unit, a filtration unit, a solvent recovery unit, a deep treatment unit, and a drainage preparation unit which are connected in sequence; Wherein, the solvent recovery unit includes a primary distillation system for separating acetonitrile recovery liquid and a secondary distillation system for separating acetonitrile residual liquid; The resource recovery process comprises the following steps: S1, passing the acetonitrile waste liquid into an inlet water preparation unit, and adjusting the pH value of the acetonitrile waste liquid to be neutral in the inlet water preparation unit; S2, passing the acetonitrile waste liquid after adjusting the pH value into a filtration unit, and filtering out suspended particles in the filtration unit; S3, passing the acetonitrile waste liquid from which suspended particles are filtered out into a solvent recovery unit, and performing two-stage distillation in the solvent recovery unit to obtain acetonitrile recovery liquid and acetonitrile residual liquid, respectively, and the acetonitrile recovery liquid is reused for production; S4, passing the acetonitrile residual liquid into a deep processing unit, and subjecting the acetonitrile residual liquid to catalytic oxidation treatment in the deep processing unit to obtain; S5. The acetonitrile residual liquid after catalytic oxidation treatment is passed into a drainage preparation unit, and the pH is adjusted in the drainage preparation unit to meet the discharge standards before being discharged.

2. The resource processing process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 1, characterized in that, In step S3, the two-stage distillation process includes: the operating temperature of the primary distillation system is 50.0°C~99.5°C, more than 98% of the acetonitrile in the acetonitrile waste liquid is recovered into the distillate to obtain acetonitrile recovery liquid, and the kettle residue enters the secondary distillation system; the operating temperature of the secondary distillation system is 99.5°C~103°C, and the kettle residue obtained from the primary distillation system is further distilled to obtain acetonitrile residue.

3. The resource processing process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 1, characterized in that, In step S4, the volume of the acetonitrile recovery liquid is 39% to 44% of the acetonitrile waste liquid, and the volume of the acetonitrile residual liquid is 56% to 61% of the acetonitrile waste liquid.

4. The resource treatment process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 1, characterized in that, In step S4, the catalytic oxidation treatment method is selected from at least one of a catalytic hydrogen peroxide oxidation process, a catalytic ozone oxidation process and an electrocatalytic oxidation process.

5. The resource processing process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 4, characterized in that, The conditions of the catalytic hydrogen peroxide oxidation process are: H2O2 dosage is mH2O2:mTOC=1~18, temperature is 40℃~120℃, pressure is 0~1.0MPa, and the volume space velocity of wastewater is 0.5h -1 ~6h -1 , the inlet water pH is 2~7.

6. The resource treatment process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 4, characterized in that: The conditions of the catalytic ozone oxidation process are: O3 dosage is mO3:mTOC=2.6~7.8, temperature is 30℃~50℃, volume space velocity of wastewater is 0.5h -1 ~6h -1 , the inlet water pH is 2~7.

7. The resource treatment process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 4, characterized in that: The conditions of the electrocatalytic oxidation process are as follows: the amount of sodium chloride added is 0~2wt.%, the constant current is 1~3A, the current density is 20mA / cm²~60mA / cm², the reaction time is 2h~6h, the positive and negative electrodes are ruthenium titanium coated electrodes or sub-titanium oxide coated electrodes, and the inlet water pH is 2~7.

8. The resource treatment process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 1, characterized in that: In step S1, the TOC of the acetonitrile waste liquid is 70,000 mg / L to 160,000 mg / L; The acetonitrile concentration in the acetonitrile waste liquid is 120g / L~280g / L.

9. The resource treatment process for high-concentration acetonitrile waste liquid in the preparative chromatography field according to claim 1, characterized in that: In step S3, the TOC of the acetonitrile recovery liquid is 200,000 mg / L to 350,000 mg / L, and the acetonitrile concentration in the acetonitrile recovery liquid is 350 g / L to 600 g / L.

10. The resource treatment process for high-concentration acetonitrile waste liquid in the field of preparative chromatography according to any one of claims 1 to 9 is applied in industrial recycling of high-concentration acetonitrile waste liquid, characterized in that: The method comprises the following steps: conducting experiments on target high-concentration acetonitrile waste liquid through the resource recovery treatment process to obtain and determine the required parameters of the treatment process; The industrial equipment is selected and customized according to the said parameters.

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