Pretreatment system and method for strongly acidic chemical wastewater containing ferrocene derivatives

Abstract

The present invention discloses a pretreatment system for strongly acidic ferrocene-derivative chemical wastewater, and also discloses a pretreatment method for strongly acidic ferrocene-derivative chemical wastewater. Advantages of the system include: ClO2 primarily treats organic pollutants in wastewater through an oxidation reaction, degrading the oxidized organic matter into products primarily containing oxygen-containing groups (carboxylic acids), which are less likely to produce carcinogenic organic chlorinated compounds and thus avoid secondary pollution; and having a long-lasting oxidizing ability, requiring a small amount of use, and exhibiting a significant COD removal effect; H2O2 also has strong oxidizing properties, and the product after oxidation and decomposition is water, which is non-toxic and pollution-free, and has the characteristics of broad spectrum, high efficiency, and green environmental protection; and is inexpensive and low-cost, thereby reducing the wastewater treatment costs of enterprises; and the combined use of ClO2 and H2O2 can destroy the chromogenic groups of substances, thereby achieving a decolorization effect. ClO2 and H2O2 can oxidize organic and inorganic harmful substances in wastewater, while simultaneously achieving decolorization and deodorization, and significantly reducing COD and BOD values.

Description

Technical field:

[0001] The present invention relates to a pretreatment system and method for chemical wastewater, and in particular to a pretreatment system and method for strongly acidic chemical wastewater containing ferrocene derivatives. Background technology:

[0002] Chemical wastewater usually has the characteristics of high concentration of organic pollutants, unstable pH, high chroma, and difficulty in treatment. In particular, chemical wastewater generated in the production process of ferrocene derivative chemical products contains ferrocene derivatives, organic solvents, inorganic salts and other substances. The pH value is about 1, and the chroma is high. The concentration of pollutants (organic matter, inorganic salts, acidity) is high, and the COD content is as high as tens of thousands or even hundreds of thousands. It has poor biodegradability and high toxicity, which poses a great threat to the ecological environment and human health. It cannot be treated using conventional biochemical treatment systems. Therefore, the treatment of this type of chemical wastewater has become a technical difficulty in this field.

[0003] At present, the treatment of this type of chemical wastewater generally uses sodium hypochlorite as an oxidant, but since chlorine can react with certain organic matter in water to generate carcinogenic organic halides, it is easy to cause secondary pollution of water bodies; moreover, sodium hypochlorite will produce Na + , which will increase the content of inorganic salts; in addition, when the temperature is high in summer, the sodium hypochlorite solution is unstable and easily decomposed if not stored properly. The decomposed sodium hypochlorite has a poor effect on sewage treatment, resulting in substandard water quality indicators after treatment; therefore, using only sodium hypochlorite as an oxidant to treat this type of sewage has a poor treatment effect, and there are unstable factors and poor reliability, which cannot meet the treatment needs and seriously restricts the normal and stable operation of chemical companies. Summary of the invention:

[0004] The first object of the present invention is to provide a pretreatment system for strongly acidic chemical wastewater containing ferrocene derivatives;

[0005] The second object of the present invention is to provide a method for pre-treating strongly acidic chemical wastewater containing ferrocene derivatives.

[0006] The first object of the present invention is implemented by the following technical solutions:

[0007] The pretreatment system for strongly acidic chemical wastewater containing ferrocene derivatives includes 1# regulating tank, ClO2 storage tank, H2O2 storage tank, liquid alkali storage tank, 1# centrifuge, 2# regulating tank and 2# centrifuge;

[0008] The water outlet of the 1# regulating tank is communicated with the water inlet of the 1# centrifuge through a pipeline, the water outlet of the 1# centrifuge is communicated with the water inlet of the 2# regulating tank through a pipeline, and the water outlet of the 2# regulating tank is communicated with the water inlet of the 2# centrifuge through a pipeline;

[0009] The liquid outlets of the liquid caustic soda storage tank, the ClO2 storage tank and the H2O2 storage tank are all connected to the 1# regulating tank through pipelines, and the liquid outlets of the ClO2 storage tank and the H2O2 storage tank are also connected to the 2# regulating tank through pipelines;

[0010] A liquid alkali regulating valve is provided on the pipeline connecting the liquid alkali storage tank and the 1# regulating tank, a 1#ClO2 regulating valve is provided on the pipeline connecting the ClO2 storage tank and the 1# regulating tank, a 2#ClO2 regulating valve is provided on the pipeline connecting the ClO2 storage tank and the 2# regulating tank, a 1#H2O2 regulating valve is provided on the pipeline connecting the H2O2 storage tank and the 1# regulating tank, and a 2#H2O2 regulating valve is provided on the pipeline connecting the H2O2 storage tank and the 2# regulating tank.

[0011] Furthermore, it also includes an evaporation treatment device, a mother liquor tank and a Fenton treatment device;

[0012] The water outlet of the 2# centrifuge is connected to the liquid inlet of the evaporation treatment device through a pipeline, the mother liquor outlet of the evaporation treatment device is connected to the inlet of the mother liquor pool through a pipeline, and the concentrated liquid outlet of the evaporation treatment device is connected to the water inlet of the Fenton treatment device through a pipeline.

[0013] The second object of the present invention is implemented by the following technical solutions:

[0014] The pretreatment method of strongly acidic chemical wastewater containing ferrocene derivatives comprises the following steps:

[0015] (1) Adjust pH: Add alkali solution to the chemical wastewater in the 1# regulating tank to adjust the pH to 3-10, so that the hydrochloric acid and Zn in the chemical wastewater 2+ The removal rate reaches 90%;

[0016] (2) Oxidative decomposition: adding ClO2 and H2O2 to the chemical wastewater in the No. 1 regulating tank after pH adjustment in step (1), and achieving a removal rate of ferrocene derivatives and organic solvents of 80% by oxidative decomposition;

[0017] (3) Filtration and impurity removal: Through centrifugal separation in the 1# centrifuge, most of the ferrocene organic matter is removed. 2+ Remove Fe 2+ The removal rate reaches 80%, and the clear liquid obtained after centrifugation is sent to the 2# regulating tank;

[0018] (4) Secondary oxidation: ClO2 and H2O2 are added to the wastewater in the No. 2 regulating tank for further oxidation and decomposition, so that the removal rate of ferrocene derivatives and organic solvents reaches about 90%, the decolorization rate reaches 95%, and the COD removal rate reaches more than 80%;

[0019] (5) Secondary impurity removal: Through the centrifugal separation of the 2# centrifuge, the Fe 2+ Removal of Fe 2+ The removal rate reaches 90%.

[0020] Furthermore, it also includes step (6) of removing COD: the clear liquid obtained after the secondary impurity removal in step (5) is sent to an evaporation treatment device for evaporation treatment, so that the remaining ferrocene derivatives and organic solvents in the wastewater are discharged with the mother liquor and enter the mother liquor pool for centralized treatment as waste liquid; the concentrated liquid obtained after evaporation is then sent to a Fenton treatment device for oxidation treatment to remove COD, so that the produced water meets the water inlet index of the biochemical treatment system.

[0021] Furthermore, in the oxidative decomposition of step (2), ClO2 and H2O2 are added in a mass ratio of chemical wastewater: ClO2:H2O2=200:2:1.

[0022] Furthermore, in the secondary oxidation of step (4), ClO2 and H2O2 are added according to the mass ratio of chemical wastewater: ClO2:H2O2=200:1:1.

[0023] Advantages of the present invention:

[0024] 1. ClO2 mainly treats organic pollutants in wastewater through oxidation reaction. The oxidized organic matter is degraded into products mainly composed of oxygen-containing groups (carboxylic acids). It is not easy to produce carcinogenic organic chlorinated compounds and will not cause secondary pollution. It has long-lasting oxidation ability, low dosage, and obvious COD removal effect. ClO2 preparation is simple and easy to operate, and is suitable for conditions with a pH of 3 to 10, with the advantage of a wide range of applications.

[0025] 2. H2O2 also has strong oxidizing properties. The product after oxidation and decomposition is water, which is non-toxic and pollution-free. It has the characteristics of broad spectrum, high efficiency, green and environmental protection, and is low in price and cost, which can reduce the wastewater treatment cost of enterprises;

[0026] 3. The combined use of ClO2 and H2O2 can destroy the chromogenic groups of the substance, thereby achieving the effect of decolorization. ClO2 and H2O2 can oxidize the organic and inorganic harmful substances in the wastewater, and at the same time can decolorize and deodorize, significantly reducing the COD and BOD values. Description of the drawings:

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic diagram of system connections in Example 1;

[0029] In the figure: 1# regulating tank 1, ClO2 storage tank 2, H2O2 storage tank 3, liquid alkali storage tank 4, 1# centrifuge 5, 2# regulating tank 6, 2# centrifuge 7, evaporation treatment device 8, mother liquor tank 9, Fenton treatment device 10, liquid alkali regulating valve 11, 1# ClO2 regulating valve 12, 2# ClO2 regulating valve 13, 1# H2O2 regulating valve 14, 2# H2O2 regulating valve 15. Specific implementation method:

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0031] Example 1:

[0032] like Figure 1 The pretreatment system for strongly acidic ferrocene-derivative chemical wastewater shown includes a 1# regulating tank 1, a ClO2 storage tank 2, a H2O2 storage tank 3, a liquid alkali storage tank 4, a 1# centrifuge 5, a 2# regulating tank 6, a 2# centrifuge 7, an evaporation treatment device 8, a mother liquor tank 9, and a Fenton treatment device 10;

[0033] The water outlet of the 1# regulating tank 1 is connected to the water inlet of the 1# centrifuge 5 through a pipeline, the water outlet of the 1# centrifuge 5 is connected to the water inlet of the 2# regulating tank 6 through a pipeline, and the water outlet of the 2# regulating tank 6 is connected to the water inlet of the 2# centrifuge 7 through a pipeline;

[0034] The liquid outlets of the liquid alkali storage tank 4, the ClO2 storage tank 2 and the H2O2 storage tank 3 are all connected to the 1# regulating tank 1 through pipelines, and the liquid outlets of the ClO2 storage tank 2 and the H2O2 storage tank 3 are also connected to the 2# regulating tank 6 through pipelines;

[0035] A liquid alkali regulating valve 11 is provided on the pipeline connecting the liquid alkali storage tank 4 and the 1# regulating tank 1, a 1#ClO2 regulating valve 12 is provided on the pipeline connecting the ClO2 storage tank 2 and the 1# regulating tank 1, a 2#ClO2 regulating valve 13 is provided on the pipeline connecting the ClO2 storage tank 2 and the 2# regulating tank 6, a 1#H2O2 regulating valve 14 is provided on the pipeline connecting the H2O2 storage tank 3 and the 1# regulating tank 1, and a 2#H2O2 regulating valve 15 is provided on the pipeline connecting the H2O2 storage tank 3 and the 2# regulating tank 6.

[0036] The water outlet of the 2# centrifuge 7 is connected to the liquid inlet of the evaporation treatment device 8 through a pipeline, the mother liquor outlet of the evaporation treatment device 8 is connected to the inlet of the mother liquor pool 9 through a pipeline, and the concentrated liquid outlet of the evaporation treatment device 8 is connected to the water inlet of the Fenton treatment device 10 through a pipeline.

[0037] In this embodiment, the evaporation treatment device 8 adopts a three-effect circulation evaporator produced by Wuxi Nuomei Machinery Co., Ltd., and the Fenton treatment device 10 adopts a Fenton treatment device produced by Yixing Ruikang Environmental Protection Technology Co., Ltd.

[0038] Example 2:

[0039] The method for treating wastewater using the pretreatment system for strongly acidic ferrocene-containing chemical wastewater provided in Example 1 comprises the following steps:

[0040] (1) pH adjustment: add alkali solution to the chemical wastewater in No. 1 regulating tank 1 (mainly containing a small amount of ferrocene derivatives, a small amount of organic solvents, 20% hydrochloric acid, zinc chloride salt solution, etc.) to adjust the pH to 3-10, so that the hydrochloric acid and Zn in the chemical wastewater are 2+ The removal rate reaches 90%;

[0041] In step (1), the purpose of adjusting the pH is: first, since the oxidation treatment needs to be carried out under certain pH conditions, otherwise the oxidation effect is poor, so adjusting the pH can improve the effect of the oxidation treatment in (2) oxidative decomposition; second, the subsequent biochemical treatment needs to be carried out within a certain pH range, and too high or too low pH will cause bacterial death and make the effluent substandard; third, neutral or alkaline pH can remove most metal ions in the form of precipitation. Since the wastewater contains zinc ions, adjusting the pH, Zn 2+ It can form Zn(OH)2 precipitation, remove impurities by filtration, and remove Zn 2+ .

[0042] (2) Oxidative decomposition: After pH adjustment in step (1), ClO2 and H2O2 are added to the chemical wastewater in the 1# regulating tank 1 according to the mass ratio of chemical wastewater: ClO2: H2O2 = 200:2:1. Through oxidative decomposition, the cyclopentadiene ring of the ferrocene derivative is first opened, so that Fe2+ Fall off; under the action of oxidants, Fe 2+ Then oxidized to Fe 3+ , Fe 3+ With OH - It can form Fe(OH)3, which has a flocculating and precipitating effect, and can quickly adsorb and flocculate suspended matter in the wastewater into giant alum flocs, forming insoluble salt precipitation. A small amount of organic solvent is also oxidized into small molecular carboxylic acid substances (the carboxylic acid substances are ultimately removed by the evaporation treatment device 8 and Fenton treatment device 10 in step (6) to remove COD), making the removal rate of ferrocene derivatives and organic solvents reach 80%;

[0043] (3) Filtration and impurity removal: The Fe(OH)3 colloid formed in the oxidative decomposition of step (2) is removed by filtration and impurity removal through centrifugal separation in the 1# centrifuge 5, thereby achieving the removal of most of the Fe 2+ The removal effect makes Fe 2+ The removal rate reaches 80%, and the clear liquid obtained after centrifugation is sent to the 2# regulating tank 6;

[0044] (4) Secondary oxidation: ClO2 and H2O2 are added to the wastewater in the No. 2 regulating tank 6 according to the mass ratio of chemical wastewater: ClO2:H2O2=200:1:1, and the remaining ferrocene derivatives and organic solvents are oxidized and decomposed again, so that the removal rate of ferrocene derivatives and organic solvents reaches about 90%, the decolorization rate reaches 95%, and the COD removal rate reaches more than 80%;

[0045] (5) Secondary impurity removal: Through the centrifugal separation of 2# centrifuge 7, the Fe 2+ Removal of Fe 2+ The removal rate reaches 90%.

[0046] (6) Removal of COD: The clear liquid obtained after the secondary impurity removal in step (5) is sent to the evaporation treatment device 8 for evaporation treatment, so that the remaining ferrocene derivatives and organic solvents in the wastewater are discharged with the mother liquor and enter the mother liquor pool 9 for centralized treatment as waste liquid; the concentrated liquid obtained after evaporation is then sent to the Fenton treatment device 10 for removal of COD through oxidation treatment, so that the COD value content reaches below 1000 mg / L, thereby making the water produced by the Fenton treatment device 10 meet the water inlet index of the biochemical treatment system.

[0047] The COD value of the treated wastewater is significantly reduced to below 1000 mg / L, the color and suspended solids of the wastewater are significantly reduced, and the content of petroleum substances is significantly reduced, which improves the biodegradability of subsequent chemical wastewater. The treated wastewater also contains petroleum substances, inorganic salts, small molecular carboxylic acid organic substances and other substances.

[0048] Since ClO2 contains 52.6% chlorine, 4+ →Cl - There are five electron transfers in the oxidation process, so its effective chlorine content is 263%, which makes ClO2 have strong reaction activation and oxidation ability. Whether under acidic or alkaline conditions, organic matter contained in wastewater (such as ferrocene aromatic ring, organic solvents, organic reducing substances) can be oxidized and removed. Some reduced inorganic metal ions in wastewater, such as Fe 2+ 、Mn 2+ etc. can also be oxidized and removed. Fe 2+ 、Mn 2+ Oxidation, specifically, Fe 2+ Oxidized to Fe 3+ , forming iron hydroxide precipitate, Mn 2+ Oxidized to Mn 4+ , forming water-insoluble manganese dioxide, which is eventually removed by filtration. The effect of H2O2 is similar to that of ClO2. Both have strong oxidizing properties, and the product of H2O2's oxidation and decomposition is water, which is non-toxic and non-polluting. Because both ClO2 and H2O2 have strong oxidizing properties, they can destroy the chromophores of substances, thereby achieving the effect of decolorization. ClO2 and H2O2 can oxidize organic and inorganic harmful substances in wastewater, while also being able to decolorize and deodorize, significantly reducing COD and BOD values.

[0049] In this embodiment, in step (2) oxidative decomposition and step (4) secondary oxidation, the order of adding ClO2 and H2O2 is ClO2 first and then H2O2. Since ClO2 needs to react for a period of time after addition, H2O2 is added 4 to 6 hours after adding ClO2. In this way, the oxidation effect can be enhanced and the reducing substances in the wastewater can react more completely.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for pretreating strongly acidic ferrocene-derivative-containing chemical wastewater, wherein the method comprises treating the strongly acidic ferrocene-derivative-containing chemical wastewater with a pretreatment system for the strongly acidic ferrocene-derivative-containing chemical wastewater, wherein the method comprises: The following steps are involved: (1) Adjust pH: Add alkali solution to the chemical wastewater in the 1# regulating tank to adjust the pH to 3-10, so that the hydrochloric acid and Zn in the chemical wastewater 2+ The removal rate reaches 90%; (2) Oxidative decomposition: adding ClO2 and H2O2 to the chemical wastewater in the No. 1 regulating tank after pH adjustment in step (1), and achieving a removal rate of ferrocene derivatives and organic solvents of 80% by oxidative decomposition; (3) Filtration and impurity removal: Through centrifugal separation in the 1# centrifuge, most of the ferrocene organic matter is removed. 2+ Remove Fe 2+ The removal rate reaches 80%, and the clear liquid obtained after centrifugation is sent to the 2# regulating tank; (4) Secondary oxidation: ClO2 and H2O2 are added to the wastewater in the No. 2 regulating tank for further oxidation and decomposition, so that the removal rate of ferrocene derivatives and organic solvents reaches about 90%, the decolorization rate reaches 95%, and the COD removal rate reaches more than 80%; (5) Secondary impurity removal: Through the centrifugal separation of the 2# centrifuge, the Fe 2+ Removal of Fe 2+ The removal rate is 90%; In step (2) oxidative decomposition and step (4) secondary oxidation, the order of adding ClO2 and H2O2 is ClO2 first and then H2O2. H2O2 is added 4 to 6 hours after adding ClO2.

2. The pretreatment method for strongly acidic ferrocene-containing chemical wastewater according to claim 1, characterized in that: The method further comprises the step (6) of removing COD: the clear liquid obtained after the secondary impurity removal in step (5) is sent to an evaporation treatment device for evaporation treatment, so that the remaining ferrocene derivatives and organic solvents in the wastewater are discharged with the mother liquor and enter a mother liquor pool for centralized treatment as waste liquid; the concentrated liquid obtained after evaporation is then sent to a Fenton treatment device for removing COD through oxidation treatment, so that the produced water meets the water inlet index of the biochemical treatment system.

3. The pretreatment method for strongly acidic ferrocene-containing chemical wastewater according to claim 1, characterized in that: In the oxidative decomposition of step (2), ClO2 and H2O2 are added in a mass ratio of chemical wastewater: ClO2: H2O2 = 200:2:

1.

4. The pretreatment method for strongly acidic ferrocene-containing chemical wastewater according to claim 1, characterized in that: In the secondary oxidation of step (4), ClO2 and H2O2 are added according to the mass ratio of chemical wastewater: ClO2:H2O2=200:1:

1.

5. The pretreatment method for strongly acidic ferrocene-containing chemical wastewater according to claim 1, characterized in that: The pretreatment system of the strongly acidic ferrocene-containing chemical wastewater comprises a 1# regulating tank, a ClO2 storage tank, a H2O2 storage tank, a liquid alkali storage tank, a 1# centrifuge, a 2# regulating tank and a 2# centrifuge; The water outlet of the 1# regulating tank is communicated with the water inlet of the 1# centrifuge through a pipeline, the water outlet of the 1# centrifuge is communicated with the water inlet of the 2# regulating tank through a pipeline, and the water outlet of the 2# regulating tank is communicated with the water inlet of the 2# centrifuge through a pipeline; The liquid outlets of the liquid caustic soda storage tank, the ClO2 storage tank and the H2O2 storage tank are all connected to the 1# regulating tank through pipelines, and the liquid outlets of the ClO2 storage tank and the H2O2 storage tank are also connected to the 2# regulating tank through pipelines; A liquid caustic soda regulating valve is provided on the pipeline connecting the liquid caustic soda storage tank and the 1# regulating tank, a 1#ClO2 regulating valve is provided on the pipeline connecting the ClO2 storage tank and the 1# regulating tank, a 2#ClO2 regulating valve is provided on the pipeline connecting the ClO2 storage tank and the 2# regulating tank, a 1#H2O2 regulating valve is provided on the pipeline connecting the H2O2 storage tank and the 1# regulating tank, and a 2#H2O2 regulating valve is provided on the pipeline connecting the H2O2 storage tank and the 2# regulating tank; It also includes an evaporation treatment device, a mother liquor tank and a Fenton treatment device; The water outlet of the 2# centrifuge is connected to the liquid inlet of the evaporation treatment device through a pipeline, the mother liquor outlet of the evaporation treatment device is connected to the inlet of the mother liquor pool through a pipeline, and the concentrated liquid outlet of the evaporation treatment device is connected to the water inlet of the Fenton treatment device through a pipeline.

Images