Indoxacarb wastewater pretreatment method

Abstract

The invention discloses an indoxacarb wastewater pretreatment method, belongs to the technical field of indoxacarb wastewater pretreatment, and mainly aims at an indoxacarb intermediate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The method comprises the following steps: firstly, adjusting the pH value to hydrolyze an indoxacarb intermediate into methanol and a 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative with carboxylate, collecting methanol, and then adjusting the waste liquid to be acidic; and adding the prepared emulsion, and carrying out liquid-liquid separation, so as to obtain waste liquid meeting the national lowest discharge standard on the basis of recovering the methanol and the 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative, and sending the waste liquid to a sewage treatment plant for further treatment. The indoxacarb wastewater pretreatment method provided by the invention has the characteristics of energy conservation, consumption reduction and capability of recovering useful components in liquid.

Description

Technical Field

[0001] The invention belongs to the technical field of indoxacarb wastewater pretreatment, and particularly relates to an indoxacarb wastewater pretreatment method. Background Art

[0002] Indoxacarb is a typical representative of the oxadiazine insecticides and the first commercialized sodium channel blocking insecticide. Its chemical name is S-7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[4-(trifluoromethoxy)-phenyl]amino]carbonyl]indeno[1,2-e][1,3,4]oxadiazine-4(3H)-carboxylic acid methyl ester, and its CAS number is 144171-61-9.

[0003] The current production process technology mainly synthesizes its important intermediate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone, and then synthesizes the final product indoxacarb on this basis. Among them, during the reaction with benzyl carbazate, 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone has a large residue. If it is not pretreated, it cannot be further degraded, which will directly affect the operation of the enterprise and become one of the technical problems that need to be solved in this field.

[0004] At present, there are few reports on the pretreatment method of indoxacarb wastewater. Among them, the main method for pretreatment of toxic wastewater is to react and precipitate high-concentration toxic wastewater or separate it by adsorption to reduce the high-concentration toxic wastewater to a treatable standard. However, the reaction precipitation method may not be effective for substances such as 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone that are difficult to precipitate. A large amount of reagents may be consumed during the reaction process, and the useful components in the wastewater may be difficult to recover. For the adsorption separation method, the adsorbent may reach adsorption saturation after a period of use and needs to be replaced or regenerated. The regeneration effect is not necessarily good, which further increases the cost. Therefore, it is urgent to provide a method for pretreatment of indoxacarb wastewater. Summary of the invention

[0005] The purpose of the present invention is to provide a method for pretreatment of indoxacarb wastewater to solve the problems described in the background technology that there are few reports on the current pretreatment methods of indoxacarb wastewater and that the commonly used reaction precipitation method and adsorption separation method have the problems that the treated substances are difficult to precipitate, the useful components are difficult to recover, and the energy and material consumption are large.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for pretreating indoxacarb wastewater comprises the following steps:

[0008] (1) In a sealed extraction and separation device, indoxacarb wastewater is added; the pH value is adjusted to 10, heated to 70-80° C., the reaction and hydrolysis are continued for 2 hours, and methanol is collected by distillation at 64-66° C. for 10 minutes; then the pH value is adjusted to 3-4, the emulsion is added, and stirred for 20-30 minutes at a stirring speed of 200 r / min to obtain a suspension a;

[0009] (2) transferring the suspension a into a phase separator and allowing it to stand for stratification to separate a first lower layer solution and a first upper layer solution, wherein the first lower layer solution is sent to a sewage treatment plant;

[0010] (3) After the first upper layer solution is heated to 20-50° C. for 9-23 minutes, it is transferred to a phase separator and allowed to stand for stratification to separate the second upper layer solution and the second lower layer solution. The second upper layer solution is a regenerated emulsion, and the second lower layer solution is a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper layer solution and the second lower layer solution are collected separately and recycled.

[0011] Wherein, the indoxacarb production wastewater contains 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone.

[0012] Wherein, the volume ratio of the indoxacarb wastewater and the emulsion is 5:1.

[0013] Wherein, the pH adjusting reagent is NaOH solid and 98wt% concentrated sulfuric acid.

[0014] Wherein, the preparation steps of the emulsion are as follows:

[0015] The membrane phase reagent and the internal phase reagent were added into the emulsifier, and the emulsifier was placed in a high-speed disperser to intermittently emulsify for 15 minutes to obtain an emulsion.

[0016] Furthermore, the rotation speed of the high-speed disperser is 2500-2800 r / min.

[0017] Furthermore, the volume ratio of the membrane phase reagent to the internal phase reagent is 1 to 2:1.

[0018] Wherein, the internal phase reagent is a 10wt% NaOH aqueous solution.

[0019] The membrane phase reagent comprises the following raw materials in parts by weight: 85 to 95 parts of civilian kerosene, 2 to 4 parts of surfactant, and 5 to 11 parts of liquid paraffin.

[0020] Furthermore, the surfactant is at least one of Span-80 and Tween-80.

[0021] Beneficial effects of the present invention:

[0022] The invention provides an indoxacarb wastewater pretreatment method, which uses an emulsion liquid membrane method to separate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone in the indoxacarb wastewater, and generates a 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative after a hydrolysis reaction by adjusting the pH. Due to the presence of a surfactant in a membrane phase reagent, the 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative can be diffused into the inner phase of the emulsion, react with an inner phase reagent NaOH aqueous solution to generate a corresponding salt, and is retained in the inner phase of the emulsion, thereby achieving efficient separation.

[0023] The indoxacarb wastewater pretreatment method provided by the present invention can recover a large number of useful components. The present invention realizes liquid-liquid separation by an emulsion liquid membrane method, and can separate useful components without changing the properties of the substance. Moreover, by adjusting the pH and temperature for hydrolysis, a large amount of methanol in 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone is extracted.

[0024] The indoxacarb wastewater pretreatment method provided by the present invention has the characteristics of energy saving and consumption reduction. The present invention realizes liquid-liquid separation through an emulsion liquid membrane method, reduces the cumbersome steps of wastewater recovery and solid waste treatment steps in the existing process, and can complete effective separation in 20 to 30 minutes, thereby reducing energy consumption and material consumption. DETAILED DESCRIPTION

[0025] The following will be combined with 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.

[0026] The civilian kerosene used in the present invention was purchased from a civilian sales department; Span-80 was purchased from Tianjin Xiensi Biochemical Technology Co., Ltd.; and liquid paraffin, with a specification of 99%, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0027] Example 1

[0028] This embodiment provides an emulsion, which is prepared by the following steps:

[0029] 8.5g of civilian kerosene, 0.2g of Span-80 and 0.5g of liquid paraffin were mixed as a membrane phase reagent, and a 10wt% NaOH aqueous solution was used as an internal phase reagent, wherein 300ml of the membrane phase reagent and 300ml of the internal phase reagent were taken. The membrane phase reagent and the internal phase reagent were added to an emulsifier, and the emulsifier was placed in a high-speed disperser, and emulsified intermittently for 15min at an emulsification speed of 2500r / min to obtain an emulsion.

[0030] Example 2

[0031] This embodiment provides an emulsion, which is prepared by the following steps:

[0032] 9g of civilian kerosene, 0.3g of Span-80 and 0.8g of liquid paraffin were mixed as a membrane phase reagent, and a 10wt% NaOH aqueous solution was used as an internal phase reagent, wherein 450ml of the membrane phase reagent and 300ml of the internal phase reagent were taken. The membrane phase reagent and the internal phase reagent were added to an emulsifier, and the emulsifier was placed in a high-speed disperser, and emulsification was performed intermittently for 15min at an emulsification speed of 2650r / min to obtain an emulsion.

[0033] Example 3

[0034] This embodiment provides an emulsion, which is prepared by the following steps:

[0035] 9.5g of civilian kerosene, 0.4g of Span-80 and 1.1g of liquid paraffin were mixed as a membrane phase reagent, and a 10wt% NaOH aqueous solution was used as an internal phase reagent, wherein 600ml of the membrane phase reagent and 300ml of the internal phase reagent were taken. The membrane phase reagent and the internal phase reagent were added to an emulsifier, and the emulsifier was placed in a high-speed disperser, and emulsified intermittently for 15min at an emulsification speed of 2800r / min to obtain an emulsion.

[0036] Example 4

[0037] This embodiment provides a method for pretreating indoxacarb wastewater, comprising the following steps:

[0038] In a sealed extraction and separation device, 1L of indoxacarb wastewater with a content of 1000mg / L was added, solid NaOH was added, the pH value was adjusted to 10, heated to 70°C, and the reaction and hydrolysis were continued for 2h, and then methanol was distilled and collected at 64°C for 10min. Subsequently, 98wt% concentrated sulfuric acid was added, the pH was adjusted to 3, 200ml of the emulsion prepared in Example 1 was added, and stirred for 20min at a stirring speed of 200r / min to obtain a suspension a.

[0039] The suspension a is transferred to a phase separator and allowed to stand for stratification to separate the first lower solution and the first upper solution, and the first lower solution is sent to a sewage treatment plant; the first upper solution is heated to 20°C for 23 minutes, and then transferred to a phase separator and allowed to stand for stratification to separate the second upper solution and the second lower solution, the second upper solution is a regenerated emulsion, and the second lower solution is a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper solution and the second lower solution are collected separately and recycled.

[0040] Example 5

[0041] This embodiment provides a method for pretreating indoxacarb wastewater, comprising the following steps:

[0042] In a sealed extraction and separation device, 1.5 L of indoxacarb wastewater with a content of 1000 mg / L was added, solid NaOH was added, the pH value was adjusted to 10, and the mixture was heated to 75° C. The reaction and hydrolysis were continued for 2 h, and then methanol was collected by distillation at 65° C. for 10 min. Subsequently, 98 wt % concentrated sulfuric acid was added to adjust the pH to 4, and 300 ml of the emulsion prepared in Example 2 was added, and the mixture was stirred for 25 min at a stirring speed of 200 r / min to obtain a suspension a.

[0043] The suspension a is transferred to a phase separator and allowed to stand for stratification to separate the first lower solution and the first upper solution, and the first lower solution is sent to a sewage treatment plant; the first upper solution is heated to 35°C for 16 minutes, and then transferred to a phase separator and allowed to stand for stratification to separate the second upper solution and the second lower solution, the second upper solution is a regenerated emulsion, and the second lower solution is a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper solution and the second lower solution are collected separately and recycled.

[0044] Example 6

[0045] This embodiment provides a method for pretreating indoxacarb wastewater, comprising the following steps:

[0046] In a sealed extraction and separation device, 2L of indoxacarb wastewater was added, solid NaOH was added, the pH value was adjusted to 10, and the mixture was heated to 80°C, and the reaction and hydrolysis were continued for 2h. Subsequently, methanol was collected by distillation at 66°C for 10min. Subsequently, 98wt% concentrated sulfuric acid was added, the pH was adjusted to 4, 400ml of the emulsion prepared in Example 3 was added, and the mixture was stirred for 30min at a stirring speed of 200r / min to obtain a suspension a.

[0047] The suspension a is transferred to a phase separator and allowed to stand for stratification to separate the first lower solution and the first upper solution, and the first lower solution is sent to a sewage treatment plant; the first upper solution is heated to 50°C for 9 minutes, and then transferred to a phase separator and allowed to stand for stratification to separate the second upper solution and the second lower solution, the second upper solution is a regenerated emulsion, and the second lower solution is a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper solution and the second lower solution are collected separately and recycled.

[0048] Comparative Example 1

[0049] This embodiment provides a method for pretreating indoxacarb wastewater, comprising the following steps:

[0050] Compared with Example 4, the emulsion prepared in Example 1 in Example 4 was replaced with 10-24 mesh activated carbon purchased from Aladdin Reagent (Shanghai) Co., Ltd., and the remaining raw materials and preparation process were the same as in Example 4.

[0051] Comparative Example 2

[0052] This embodiment provides a method for pretreating indoxacarb wastewater, comprising the following steps:

[0053] Compared with Example 4, the preparation process of suspension a is as follows: in a sealed extraction and separation device, 1L of indoxacarb wastewater with a content of 1000mg / L is added, then, 98wt% concentrated sulfuric acid is added, the pH is adjusted to 3, 200ml of the emulsion prepared in Example 1 is added, and stirring is carried out for 20min at a stirring speed of 200r / min to obtain suspension a. The remaining raw materials and preparation process are the same as in Example 4.

[0054] The indoxacarb wastewater pretreatment methods provided in Examples 4 to 6, Comparative Examples 1 and 2 were evaluated. The GB8978-1996 comprehensive sewage discharge standard was adopted to evaluate the wastewater to be further treated, and specifically, the content of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in the lower aqueous phase was detected by high performance liquid chromatography.

[0055] HPLC conditions: Chricel OD-H column (90.46cm×25cm), column temperature 25℃, flow rate 1mL / min, mobile phase V (n-hexane): V (isopropanol) = 90:10, detection wavelength 254nm; injection volume 20μL. Take an appropriate amount of the wastewater solution to be tested, dissolve it completely with the mobile phase, and prepare a test solution with a concentration of about 0.1mg / mL. Take 20μL of the test solution, inject it into the chromatograph, record the chromatogram, and calculate by area normalization method to obtain the residual amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in the wastewater. The results are shown in Table 1:

[0056] Table 1

[0057]

[0058] As can be seen from Table 1, the residual amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in Examples 4 to 6 is less than 0.38%, which meets the minimum standard of the National Integrated Wastewater Discharge Standard GB8978-1996. Compared with Comparative Example 1, on the basis of meeting the standard, regeneration is also more convenient; compared with Comparative Example 2, not only can methanol be recovered, but also the separation amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives can be greatly increased. This is because when 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone enters the inner phase of the emulsion, only part of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone reacts with the inner phase solvent, and a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone escapes from the inner phase.

[0059] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0060] 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 pretreating indoxacarb wastewater, characterized in that: The following steps are involved: (1) In a sealed extraction and separation device, indoxacarb wastewater is added; the pH value is adjusted to 10, heated to 70-80° C., the reaction and hydrolysis are continued for 2 hours, and methanol is collected by distillation at 64-66° C. for 10 minutes; then the pH value is adjusted to 3-4, the emulsion is added, and stirred for 20-30 minutes at a stirring speed of 200 r / min to obtain a suspension a; (2) transferring the suspension a into a phase separator and allowing it to stand for stratification to separate a first lower layer solution and a first upper layer solution, wherein the first lower layer solution is sent to a sewage treatment plant; (3) After heating the first upper layer solution to 20-50° C. for 9-23 min, the first upper layer solution is transferred to a phase separator for standing and stratification to separate the second upper layer solution and the second lower layer solution. The second upper layer solution and the second lower layer solution are collected and recycled.

2. The indoxacarb wastewater pretreatment method according to claim 1, characterized in that: The indoxacarb production wastewater contains 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone.

3. The indoxacarb wastewater pretreatment method according to claim 1, characterized in that: The volume ratio of the indoxacarb wastewater to the emulsion is 5:

1.

4. The indoxacarb wastewater pretreatment method according to claim 1, characterized in that: The reagents for adjusting pH are solid NaOH and 98 wt % concentrated sulfuric acid.

5. The indoxacarb wastewater pretreatment method according to claim 1, characterized in that: The preparation steps of the emulsion are as follows: The membrane phase reagent and the internal phase reagent were added into the emulsifier, and the emulsifier was placed in a high-speed disperser to intermittently emulsify for 15 minutes to obtain an emulsion.

6. The indoxacarb wastewater pretreatment method according to claim 5, characterized in that: The rotation speed of the high-speed disperser is 2500-2800 r / min.

7. The indoxacarb wastewater pretreatment method according to claim 5, characterized in that: The volume ratio of the membrane phase reagent to the internal phase reagent is 1 to 2:

1.

8. The indoxacarb wastewater pretreatment method according to claim 5, characterized in that: The internal phase reagent is a 10 wt % NaOH aqueous solution.

9. The indoxacarb wastewater pretreatment method according to claim 5, characterized in that: The membrane phase reagent comprises the following raw materials in parts by weight: 85 to 95 parts of civilian kerosene, 2 to 4 parts of surfactant, and 5 to 11 parts of liquid paraffin.

10. The indoxacarb wastewater pretreatment method according to claim 9, characterized in that: The surfactant is at least one of Span-80 and Tween-80.

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