Treatment and resource recycling method of pipemidic acid production wastewater

Abstract

The invention discloses a pipemidic acid production wastewater treatment and resource recycling method, and belongs to the technical field of wastewater treatment.The method comprises the following steps that S1, suspended solids in pipemidic acid production wastewater are removed through gravity precipitation; s2, alkali is added to adjust the PH value to 9; s3, removing pipemidic acid in the pipemidic acid production wastewater through resin adsorption; s4, desalination treatment: salt is recycled, and after desalination treatment, the wastewater enters a production washing procedure or is directly discharged; s5, resin desorption and regeneration treatment: the resin is recycled, and desorption liquid enters a recycling process; s6, acidification, salting-out and filtration treatment: directly entering a pipemidic acid production process to serve as a raw material or entering a next batch of desorption agent to be circularly applied, and recycling pipemidic acid; unification of wastewater treatment and resource recycling is achieved, and good environmental benefits, social benefits and economic benefits are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and specifically relates to a method for treating wastewater produced by pipemidic acid and recycling it as a resource. Background Art

[0002] Pipemidic acid is a chemically synthesized antibacterial drug that mainly fights Gram-negative bacteria. This type of drug is widely used in clinical practice because of its broad antibacterial spectrum, strong antibacterial activity, convenient oral administration, no cross-resistance, low price, good pharmacokinetic characteristics and reliable clinical efficacy.

[0003] At present, the production method of pipemidic acid generally uses urea as the starting material and 2,4-dichloropyrimidine-5-carboxylic acid methyl ester as the main component to synthesize pipemidic acid. This method will produce wastewater during the production process. The wastewater is an organic wastewater with high concentration, high salt content and high biological toxicity. If it is discharged directly, it may have an impact on the environment. However, there is currently no economically feasible method to achieve the standard discharge of pipemidic acid production wastewater.

[0004] In view of this, a method for treating pipemidic acid production wastewater and recycling it as a resource is designed to solve the above problems. Summary of the invention

[0005] To solve the problems raised in the above background technology. The present invention provides a method for treating wastewater produced by pipemidic acid and recycling it as a resource, which can not only effectively treat wastewater produced by pipemidic acid to achieve standard discharge, but also enrich and recover pipemidic acid and its intermediates therein, realize the unity of wastewater treatment and resource recycling, and has good environmental benefits, social benefits and economic benefits.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for treating and recycling wastewater from pipemidic acid production, comprising the following steps:

[0007] S1: The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop is subjected to gravity sedimentation to remove suspended solids in the wastewater to obtain pipemidic acid production wastewater without suspended solids, and the CODcr is reduced from 46000 mg / L to 30000 mg / L;

[0008] S2: adjusting the pH value of the pipemidic acid production wastewater without suspended matter to 9 by adding alkali to obtain light yellow pipemidic acid production wastewater;

[0009] S3: removing pipemidic acid from the above-mentioned light yellow pipemidic acid production wastewater through resin adsorption to obtain colorless, transparent and pipemidic acid-free production wastewater with a CODcr of less than 100 mg / L and a pipemidic acid concentration of less than 20 mg / L, which can be directly discharged in compliance with the discharge standards;

[0010] S4: desalting the colorless and transparent production wastewater, recycling the salt in the colorless and transparent production wastewater, and the desalted colorless and transparent production wastewater enters the production washing process or is directly discharged;

[0011] S5: performing a desorption and regeneration process on the macroporous adsorption resin to recycle the macroporous adsorption resin, and the desorption liquid after the desorption and regeneration process enters a recycling process;

[0012] S6: The desorption liquid whose concentration meets the requirements of the pipemidic acid production process is subjected to acidification, salting-out and filtration treatment to recycle the pipemidic acid, or directly enters the pipemidic acid production process to be recycled as a raw material; the desorption liquid whose concentration does not meet the requirements of the pipemidic acid production process is entered into the preparation of the next batch of desorbents for recycling.

[0013] Furthermore, in step S2, the alkaline substance added as alkali includes solid sodium hydroxide.

[0014] Furthermore, in step S3, the resin adsorption adopts a double-column series adsorption and single-column desorption method, that is, three adsorption columns I, II and III with built-in macroporous adsorption resins are set, and columns I and II are first connected in series for downstream adsorption, wherein column I serves as a primary adsorption column and column II serves as a secondary adsorption column. When column I is saturated with adsorption, columns II and III are switched to downstream adsorption in series, wherein column II serves as a primary adsorption column and column III serves as a secondary adsorption column, and column I performs reverse desorption, and the operation is repeated in this way.

[0015] Furthermore, in step S3, the macroporous adsorption resin in the adsorption column is a styrene-divinylbenzene copolymer macroporous adsorption resin, including any one of XDA-200 resin, H-103 resin, LS-200 resin or Amberlite XAD-4 resin.

[0016] Furthermore, in step S3, the adsorption temperature of the adsorption column is 0-40°C, the flow rate is 0.5-5BV / h, and the processing volume is 10-15BV / batch.

[0017] Furthermore, in step S4, the desalination treatment includes any one of recycling salt obtained by reverse osmosis membrane, recycling salt obtained by anion and cation exchange system, recycling sodium chloride by multi-effect evaporation crystallization, and reusing distilled water or recycling salt obtained by electrodialysis.

[0018] Furthermore, in step S5, the desorbent for desorption regeneration treatment includes any one of NaOH+H2O, alkaline methanol solution or alkaline ethanol solution, wherein the NaOH+H2O desorbent is 1BV2mol / LNaOH+1BV1mol / LNaOH+3BVH2O, the desorption temperature is 0-5°C, and the desorption flow rate is 0.5-2BV / h, the alkaline methanol solution desorbent is 1BV1mol / LNaOH+1BV75% industrial methanol+3BVH2O, the desorption temperature is 30-50°C, and the desorption flow rate is 0.5~2BV / h, and the alkaline ethanol solution desorbent is 1BV1mol / LNaOH+1BV75% ethanol+3BVH2O, the desorption temperature is 30-70°C, and the desorption flow rate is 0.5~2BV / h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention can not only effectively treat pipemidic acid production wastewater to achieve standard discharge, but also can enrich and recover pipemidic acid and its intermediates therein, realize the unification of wastewater treatment and resource recovery and utilization, and has good environmental benefits, social benefits and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of the method for treating wastewater produced by pipemidic acid and recycling it as a resource. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 The present invention provides the following technical solution: a method for treating wastewater from pipemidic acid production and recycling it as a resource, comprising the following steps:

[0024] S1: The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop is subjected to gravity sedimentation to remove suspended solids in the wastewater to obtain pipemidic acid production wastewater without suspended solids, and the CODcr is reduced from 46000 mg / L to 30000 mg / L;

[0025] S2: adjusting the pH value of the pipemidic acid production wastewater without suspended matter to 9 by adding alkali to obtain light yellow pipemidic acid production wastewater;

[0026] S3: removing pipemidic acid from the above-mentioned light yellow pipemidic acid production wastewater through resin adsorption to obtain colorless, transparent and pipemidic acid-free production wastewater with a CODcr of less than 100 mg / L and a pipemidic acid concentration of less than 20 mg / L, which can be directly discharged in compliance with the discharge standards;

[0027] S4: desalting the colorless and transparent production wastewater, recycling the salt in the colorless and transparent production wastewater, and the desalted colorless and transparent production wastewater enters the production washing process or is directly discharged;

[0028] S5: performing a desorption and regeneration process on the macroporous adsorption resin to recycle the macroporous adsorption resin, and the desorption liquid after the desorption and regeneration process enters a recycling process;

[0029] S6: The desorption liquid whose concentration meets the requirements of the pipemidic acid production process is subjected to acidification, salting-out and filtration treatment to recycle the pipemidic acid, or directly enters the pipemidic acid production process to be recycled as a raw material; the desorption liquid whose concentration does not meet the requirements of the pipemidic acid production process is entered into the preparation of the next batch of desorbents for recycling.

[0030] Specifically, in step S2, the alkaline substance added includes solid sodium hydroxide.

[0031] Specifically, in step S3, the resin adsorption adopts a double-column series adsorption and single-column desorption method, that is, three adsorption columns I, II and III with built-in macroporous adsorption resins are set, and columns I and II are first connected in series for downstream adsorption, wherein column I serves as a primary adsorption column and column II serves as a secondary adsorption column. When column I is saturated with adsorption, columns II and III are switched to downstream adsorption in series, wherein column II serves as a primary adsorption column and column III serves as a secondary adsorption column, and column I is reversely desorbed, and the operation is repeated in this way.

[0032] Specifically, in step S3, the macroporous adsorption resin in the adsorption column is a styrene-divinylbenzene copolymer macroporous adsorption resin, including any one of CHA-111, H-103, X-5, XDA-200, LS-200, AB-8, NDA-150, D-113, D-101, AmberliteXAD-4, XAD-7, XAD-16, Diaion HP or Sepabeads SP.

[0033] Preferred is XDA-200 resin, H-103 resin, LS-200 resin or Amberlite XAD-4 resin.

[0034] Specifically, in step S3, the adsorption temperature of the adsorption column is 0-40°C, the flow rate is 0.5-5BV / h, and the processing volume is 10-15BV / batch.

[0035] Specifically, in step S4, the desalination treatment includes any one of recovering salt by reverse osmosis membrane, recovering salt by anion and cation exchange system, recovering sodium chloride by multi-effect evaporation crystallization, and reusing distilled water or recovering salt by electrodialysis.

[0036] Specifically, in step S5, the desorbent for desorption regeneration treatment includes any one of NaOH+H2O, alkaline methanol solution or alkaline ethanol solution, wherein the concentration of NaOH solution is 0.5-4mol / L, the desorption temperature is 0-5°C, and the desorption flow rate is 0.5-2BV / h. The desorption temperature of the alkaline methanol solution is 30-50°C, and the desorption flow rate is 0.5~2BV / h. The desorption temperature of the alkaline ethanol solution is 30-70°C, and the desorption flow rate is 0.5~2BV / h.

[0037] The desorbent of NaOH+H2O is preferably 1BV2mol / LNaOH+1BV1mol / LNaOH+3BVH2O, and the desorbent of alkaline methanol solution or alkaline ethanol solution is preferably 1BV1mol / LNaOH+1BV75% ethanol (or industrial methanol)+3BVH2O. The high-concentration desorbent is distilled to recover methanol or ethanol, and the residue is acidified, neutralized and filtered to recover organic substances such as pipemidic acid. Specific embodiment 1

[0039] The yellow pipemidic acid production wastewater with a CODcr of 46000 mg / L and a pipemidic acid concentration of 5875 mg / L discharged from the pipemidic acid production workshop was filtered to remove suspended matter by gravity sedimentation at room temperature;

[0040] The pH value of the yellow pipemidic acid production wastewater from which the suspended matter has been removed is adjusted to 9, thereby converting the yellow pipemidic acid production wastewater into light yellow pipemidic acid production wastewater;

[0041] 10 ml of XDA-200 macroporous adsorption resin was loaded into a glass adsorption column with a diameter of 15×350 mm and a heat-insulating cover, wherein the XDA-200 macroporous adsorption resin was produced by Xi'an Lanxiao Technology Co., Ltd.;

[0042] At 10±5℃, the light yellow pipemidic acid production wastewater passed through the resin column at a flow rate of 10mL / h, and the wastewater treatment volume was 100mL / batch. The adsorbed wastewater was colorless and transparent, the CODcr concentration dropped to 62mg / L, and the pipemidic acid concentration dropped to 5mg / L. The removal rates of both were greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard;

[0043] At a temperature of 60±5°C, 10mL of 2mol / L NaOH solution, 10mL of 1mol / L NaOH solution and 30mL of distilled water were used in sequence at a flow rate of 5mL / h to desorb the adsorbed XDA-200 macroporous adsorption resin. The desorption rate of pipemidic acid was >98%, and the purity of the recovered pipemidic acid was >98.5%. The resin after desorption could be reused.

[0044] The first 200 mL of desorption liquid is yellow, which is a high-concentration desorption liquid. It is returned to the acid precipitation step of the pipemidic acid production process. It can also be directly acidified, alkalized and neutralized to obtain the pipemidic acid product.

[0045] The 300 mL flowing out later is low-concentration desorption liquid, which is used to prepare the next batch of desorption agent. Specific embodiment 2

[0047] The adsorption device and operation are the same as those in the first embodiment, except that the wastewater adsorbed is colorless and transparent when the flow rate is 20 mL / h through the resin column, the CODcr concentration is reduced to 75 mg / L, and the pipemidic acid concentration is reduced to 8.6 mg / L;

[0048] The desorption device and operation are the same as those in the first specific embodiment. The desorption rate of pipemidic acid is greater than 98%, the purity of the recovered pipemidic acid is greater than 98%, and the resin after desorption can be reused. Specific embodiment three

[0050] The adsorption device and operation are the same as those in the first embodiment, except that the wastewater adsorbed by the resin column at a temperature of 30±5°C is colorless and transparent, the CODcr concentration is reduced to 94 mg / L, and the pipemidic acid concentration is reduced to 14 mg / L;

[0051] The desorption device and operation are the same as those in the first specific embodiment. The desorption rate of pipemidic acid is higher than 97.5%, the purity of the recovered pipemidic acid is higher than 98%, and the resin after desorption can be reused. Specific embodiment 4

[0053] The adsorption device and operation are the same as those in the first embodiment. The adsorbed wastewater is colorless and transparent, the CODcr concentration is reduced to 62 mg / L, and the pipemidic acid concentration is reduced to 6.5 mg / L. The removal rates of both are greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard.

[0054] The desorption device and operation are the same as those in the first embodiment, except that alkaline ethanol is used as the desorbent, the desorption temperature is 60±5°C, the flow rate is 5 mL / h, the desorption rate of pipemidic acid is >99.5%, and the purity of the recovered pipemidic acid is >98.5%;

[0055] The ethanol desorption liquid is first subjected to vacuum distillation or rectification to recover the ethanol, and the residual liquid is filtered, acidified, alkalized and neutralized to recover the pipemidic acid;

[0056] The low-concentration desorption liquid flows out later and is used to prepare the next batch of desorption agent. Specific embodiment five

[0058] The adsorption device and operation are the same as those in the first embodiment. The adsorbed wastewater is colorless and transparent, the CODcr concentration is reduced to 62 mg / L, and the pipemidic acid concentration is reduced to 7.5 mg / L. The removal rates of both are greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard.

[0059] The desorption device and operation are the same as those in the first embodiment, except that the desorption temperature is 40±5°C, the flow rate is 5 mL / h, the desorption rate of pipemidic acid is >94%, and the purity of the recovered pipemidic acid is >98%;

[0060] The first 200 mL of desorption liquid is yellow, which is a high-concentration desorption liquid. It is returned to the acid precipitation step of the pipemidic acid production process. It can also be directly acidified, alkalized and neutralized to obtain the pipemidic acid product.

[0061] The 300 mL flowing out later is low-concentration desorption liquid, which is used to prepare the next batch of desorption agent. Specific embodiment six

[0063] The adsorption device and operation are the same as those in the first embodiment. The adsorbed wastewater is colorless and transparent, the CODcr concentration is reduced to 62 mg / L, and the pipemidic acid concentration is reduced to 10 mg / L. The removal rates of both are greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard.

[0064] The desorption device and operation are the same as those in the first embodiment, except that the flow rate is 10 mL / h, the desorption rate of pipemidic acid is > 95%, and the purity of the recovered pipemidic acid is > 98%;

[0065] The first 200 mL of desorption liquid is yellow, which is a high-concentration desorption liquid. It is returned to the acid precipitation step of the pipemidic acid production process. It can also be directly acidified, alkalized and neutralized to obtain the pipemidic acid product.

[0066] The 300 mL flowing out later is low-concentration desorption liquid, which is used to prepare the next batch of desorption agent. Specific embodiment seven

[0068] The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop with a CODcr of 45870 mg / L and a pipemidic acid concentration of 5632 mg / L was filtered to remove suspended matter by gravity sedimentation at room temperature;

[0069] The pH value of the yellow pipemidic acid production wastewater from which the suspended matter has been removed is adjusted to 9, thereby converting the yellow pipemidic acid production wastewater into light yellow pipemidic acid production wastewater;

[0070] 100 ml of XDA-200 macroporous adsorption resin was loaded into a glass adsorption column with a diameter of 25×600 mm and a heat-insulating cover, wherein the XDA-200 macroporous adsorption resin was produced by Xi'an Lanxiao Technology Co., Ltd.;

[0071] At 10±5℃, the light yellow pipemidic acid production wastewater passed through the resin column at a flow rate of 100mL / h, and the wastewater treatment capacity was 1000mL / batch. The adsorbed wastewater was colorless and transparent, the CODcr concentration dropped to 54mg / L, and the pipemidic acid concentration dropped to 6mg / L, which can meet the national pharmaceutical industry wastewater discharge first-level standard;

[0072] At a temperature of 60±5°C, 100mL of 2mol / L NaOH solution, 100mL of 1mol / L NaOH solution and 300mL of distilled water were used in sequence at a flow rate of 50mL / h to desorb the adsorbed XDA-200 macroporous adsorption resin. The desorption rate of pipemidic acid was >98%, and the purity of the recovered pipemidic acid was >98.5%. The resin after desorption could be reused.

[0073] The first 200 mL of desorption liquid is yellow, which is a high-concentration desorption liquid. It is returned to the acid precipitation step of the pipemidic acid production process. It can also be directly acidified, alkalized and neutralized to obtain the pipemidic acid product.

[0074] The 300 mL flowing out later is low-concentration desorption liquid, which is used to prepare the next batch of desorption agent. Specific embodiment eight

[0076] The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop with a CODcr of 46280 mg / L and a pipemidic acid concentration of 6132 mg / L was filtered to remove suspended matter by gravity sedimentation at room temperature;

[0077] The pH value of the yellow pipemidic acid production wastewater from which the suspended matter has been removed is adjusted to 9, thereby converting the yellow pipemidic acid production wastewater into light yellow pipemidic acid production wastewater;

[0078] 100 ml of XDA-200 macroporous adsorption resin was loaded into a glass adsorption column with a diameter of 25×600 mm and a heat-insulating cover, wherein the XDA-200 macroporous adsorption resin was produced by Xi'an Lanxiao Technology Co., Ltd.;

[0079] At 30±5℃, the light yellow pipemidic acid production wastewater passed through the resin column at a flow rate of 200mL / h, and the wastewater treatment capacity was 1000mL / batch. The adsorbed wastewater was colorless and transparent, the CODcr concentration dropped to 87mg / L, and the pipemidic acid concentration dropped to 16mg / L. The removal rates of both were greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard.

[0080] At a temperature of 60±5°C, 100mL of 2mol / L NaOH solution, 100mL of 1mol / L NaOH solution and 300mL of distilled water were used in sequence at a flow rate of 50mL / h to desorb the adsorbed XDA-200 macroporous adsorption resin. The desorption rate of pipemidic acid was >98.5%, and the purity of the recovered pipemidic acid was >98.5%. The resin after desorption could be reused.

[0081] The first 200 mL of desorption liquid is yellow, which is a high-concentration desorption liquid. It is returned to the acid precipitation step of the pipemidic acid production process. It can also be directly acidified, alkalized and neutralized to obtain the pipemidic acid product.

[0082] The 300 mL flowing out later is low-concentration desorption liquid, which is used to prepare the next batch of desorption agent. Specific embodiment nine

[0084] The adsorption device and operation are the same as those in specific embodiment 6. The adsorbed wastewater is colorless and transparent, the CODcr concentration is reduced to 62 mg / L, and the pipemidic acid concentration is reduced to 10 mg / L. The removal rates of both are greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard.

[0085] The desorption device and operation are the same as those in the sixth specific embodiment, except that alkaline ethanol is used as the desorbent, the desorption temperature is 60±5°C, the flow rate is 50mL / h, the desorption rate of pipemidic acid is>99.5%, and the purity of the recovered pipemidic acid is>99%;

[0086] The ethanol desorption liquid is first subjected to vacuum distillation or rectification to recover the ethanol, and the residual liquid is filtered, acidified, alkalized and neutralized to recover the pipemidic acid. Specific embodiment ten

[0088] The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop with a CODcr of 38000 mg / L and a pipemidic acid concentration of 6875 mg / L was filtered to remove suspended matter by gravity sedimentation at room temperature;

[0089] The pH value of the yellow pipemidic acid production wastewater from which the suspended matter has been removed is adjusted to 9, thereby converting the yellow pipemidic acid production wastewater into light yellow pipemidic acid production wastewater;

[0090] Three glass adsorption columns with a diameter of 320×3000mm and thermal insulation sets were selected, and three 1L XDA-200 macroporous adsorption resins were respectively loaded into three glass adsorption columns with a diameter of 320×3000mm and thermal insulation sets. Among them, the XDA-200 macroporous adsorption resin was produced by Xi'an Lanxiao Technology Co., Ltd.;

[0091] The light yellow pipemidic acid production wastewater was treated with 0.1m 3 / h flow rate pumped into the adsorption column, columns I and II are connected in series for downstream adsorption, column I is used as the primary adsorption column, column II is used as the secondary adsorption column. When column I is saturated with adsorption, column II and III are connected in series for downstream adsorption, column II is used as the primary adsorption column, column III is used as the secondary adsorption column, and column I is reversely desorbed. This cycle is repeated and the wastewater treatment capacity is 1m 3 / batch, the adsorbed wastewater is colorless and transparent, CODcr concentration is reduced to 80mg / L, and pipemidic acid concentration is reduced to 25mg / L, both removal rates are greater than 99%, and the effluent can meet the national pharmaceutical industry wastewater discharge first-level standard;

[0092] The I column was desorbed with NaOH solution in reverse order. The residual night in the I column was first drained out, and then hot water was injected into the jacket to raise the temperature of the adsorption column to 85°C. 3 The concentration is 2mol / LNaOH solution, 0.1m 3 The concentration of 1.0 mol / L NaOH solution and 0.2 M 3 Distilled water at 0.05m 3 / h flow rate resin for reverse desorption, pipemidic acid desorption rate> 99%, the recovered pipemidic acid purity> 98%, the resin after desorption can be reused;

[0093] 0.15m of the initial outflow 3 The desorption liquid is a high-concentration desorption liquid, which is returned to the acid precipitation step of the pipemidic acid production process;

[0094] 0.25m after outflow 3 It is a low concentration desorption liquid, used to prepare the next batch of desorption agent;

[0095] After desorption, column I will be used as the secondary adsorption column for the third batch of wastewater adsorption operation. When treating the second batch of wastewater, column II will be used as the primary adsorption column and column III will be used as the secondary adsorption column. Specific embodiment eleven

[0097] The adsorption resins in the specific embodiments 1 to 8 were replaced with domestic H-103, LS-200, D-113 and AmberliteXAD-4. Except for the change in the treatment amount of each batch of wastewater, the other results remained basically unchanged. The adsorbed wastewater was colorless and transparent, the CODcr concentration dropped to below 100 mg / L, and the pipemidic acid concentration dropped to below 20 mg / L. The removal rates of both were greater than 99%, which can meet the national pharmaceutical industry wastewater discharge first-level standard;

[0098] The desorption rate of pipemidic acid was >98%, and the purity of the recovered pipemidic acid was >98.5%.

[0099] The above specific embodiments all show that the present application can not only effectively treat the wastewater produced by pipemidic acid to achieve standard discharge, but also enrich and recover the pipemidic acid and its intermediates therein, realize the unity of wastewater treatment and resource recycling, and has good environmental, social and economic benefits.

[0100] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating and recycling wastewater from pipemidic acid production, characterized in that: The following steps are involved: S1: The yellow pipemidic acid production wastewater discharged from the pipemidic acid production workshop is subjected to gravity sedimentation to remove suspended solids in the wastewater to obtain pipemidic acid production wastewater without suspended solids, and the CODcr is reduced from 46000 mg / L to 30000 mg / L; S2: adjusting the pH value of the pipemidic acid production wastewater without suspended matter to 9 by adding alkali to obtain light yellow pipemidic acid production wastewater; S3: removing pipemidic acid from the above-mentioned light yellow pipemidic acid production wastewater through resin adsorption to obtain colorless, transparent and pipemidic acid-free production wastewater with a CODcr of less than 100 mg / L and a pipemidic acid concentration of less than 20 mg / L, which can be directly discharged in compliance with the discharge standards; S4: desalting the colorless and transparent production wastewater, recycling the salt in the colorless and transparent production wastewater, and the desalted colorless and transparent production wastewater enters the production washing process or is directly discharged; S5: performing a desorption and regeneration process on the macroporous adsorption resin to recycle the macroporous adsorption resin, and the desorption liquid after the desorption and regeneration process enters a recycling process; S6: The desorption liquid whose concentration meets the requirements of the pipemidic acid production process is subjected to acidification, salting-out and filtration treatment to recycle the pipemidic acid, or directly enters the pipemidic acid production process to be recycled as a raw material; the desorption liquid whose concentration does not meet the requirements of the pipemidic acid production process is entered into the preparation of the next batch of desorbents for recycling.

2. The method for treating and recycling wastewater from pipemidic acid production according to claim 1, characterized in that: In the step S2, the alkaline substance added includes solid sodium hydroxide.

3. The method for treating and recycling wastewater from pipemidic acid production according to claim 1, characterized in that: In the step S3, the resin adsorption adopts the method of double-column series adsorption and single-column desorption, that is, three adsorption columns I, II and III with built-in macroporous adsorption resin are set, and columns I and II are first connected in series for downstream adsorption, wherein column I is used as the primary adsorption column and column II is used as the secondary adsorption column. When column I is saturated with adsorption, columns II and III are switched to downstream adsorption in series, wherein column II is used as the primary adsorption column and column III is used as the secondary adsorption column, and column I is reversely desorbed at the same time, and the operation is repeated in this way.

4. The method for treating and recycling wastewater from pipemidic acid production according to claim 3, characterized in that: In step S3, the macroporous adsorption resin in the adsorption column is a styrene-divinylbenzene copolymer macroporous adsorption resin, including any one of XDA-200 resin, H-103 resin, LS-200 resin or Amberlite XAD-4 resin.

5. The method for treating and recycling wastewater from pipemidic acid production according to claim 3, characterized in that: In step S3, the adsorption temperature of the adsorption column is 0-40°C, the flow rate is 0.5-5BV / h, and the processing volume is 10-15BV / batch.

6. The method for treating and recycling wastewater from pipemidic acid production according to claim 1, characterized in that: In step S4, the desalination treatment includes any one of recycling salt obtained through a reverse osmosis membrane, recycling salt obtained through an anion and cation exchange system, recycling sodium chloride by multi-effect evaporation crystallization, and reusing distilled water or recycling salt obtained through electrodialysis.

7. The method for treating and recycling wastewater from pipemidic acid production according to claim 1, characterized in that: In the step S5, the desorbent for desorption regeneration treatment includes any one of NaOH+H2O, alkaline methanol solution or alkaline ethanol solution, wherein the NaOH+H2O desorbent is 1BV2mol / LNaOH+1BV1mol / LNaOH+3BVH2O, the desorption temperature is 0-5°C, and the desorption flow rate is 0.5-2BV / h, the alkaline methanol solution desorbent is 1BV1mol / LNaOH+1BV75% industrial methanol+3BVH2O, the desorption temperature is 30-50°C, and the desorption flow rate is 0.5-2BV / h, and the alkaline ethanol solution desorbent is 1BV1mol / LNaOH+1BV75% ethanol+3BVH2O, the desorption temperature is 30-70°C, and the desorption flow rate is 0.5-2BV / h.

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