A treatment process for p-nitrochlorobenzene wastewater

Abstract

The application discloses a treatment process of p-nitrochlorobenzene wastewater and belongs to the technical field of wastewater treatment. The treatment process comprises the following steps: in the first step, the p-nitrochlorobenzene wastewater is introduced into a composite oxidation tank, the pH of the p-nitrochlorobenzene wastewater is adjusted to 5-6, a functional additive and a persulfate salt are added into the composite oxidation tank, and stirring is carried out for 3-4 hours to obtain oxidation wastewater; and in the second step, the oxidation wastewater is filtered, the filtrate is discharged after detection, and the filtrate that does not reach the qualified standard is introduced into the composite oxidation tank for cyclic treatment. The functional additive is a (3-carboxylpropyl) triphenylphosphonium bromide modified zeolite loaded with Pd / Fe. In view of the problem that the p-nitrochlorobenzene is difficult to be directly oxidized and degraded, the p-nitrochlorobenzene is reduced into an amine intermediate product that is easy to be degraded by introducing the functional additive, and then the amine intermediate product is oxidized and degraded by using the persulfate salt, so that the content of the p-nitrochlorobenzene in the wastewater is effectively reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a treatment process for p-nitrochlorobenzene wastewater. BACKGROUND

[0002] P-nitrochlorobenzene is an important production raw material in the rubber, pharmaceutical, pesticide and photographic material industries, and is also an intermediate for producing azo dyes and vulcanization dyes. A large amount of wastewater is discharged in the production process of p-nitrochlorobenzene, and the organic matter content in the wastewater is very high, including p-nitrochlorobenzene, nitrochlorophenol, nitrophenol and the like. Among them, the amount of p-nitrochlorobenzene is the largest, and the toxicity is also relatively large, which is very harmful to the ecological environment and human health. Therefore, how to treat the wastewater containing p-nitrochlorobenzene is a current research hotspot.

[0003] At present, the treatment methods for p-nitrochlorobenzene wastewater include physical and chemical methods, advanced oxidation methods and biological methods. The physical and chemical adsorption method cannot completely remove p-nitrochlorobenzene, and is easy to cause secondary pollution. The biodegradability of p-nitrochlorobenzene is poor, which leads to low treatment effect of the biological method for p-nitrochlorobenzene wastewater. The molecule of p-nitrochlorobenzene has a non-planar structure characteristic. The nitro group and the chlorine atom on the benzene ring are both electron-withdrawing groups, which greatly reduces the electron cloud density on the benzene ring, and makes the benzene ring cracking more difficult. The direct oxidation method is difficult to open the benzene ring, resulting in poor treatment effect. Therefore, how to provide a treatment process for p-nitrochlorobenzene wastewater with good treatment effect is a technical problem to be solved at present. SUMMARY

[0004] The purpose of the present application is to provide a treatment process for p-nitrochlorobenzene wastewater, which solves the problem of poor effect of the direct oxidation method for treating p-nitrochlorobenzene wastewater.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A treatment process for p-nitrochlorobenzene wastewater, comprising the following steps:

[0007] In the first step, the p-nitrochlorobenzene wastewater is introduced into a composite oxidation tank, the pH of the p-nitrochlorobenzene wastewater is adjusted to 5-6, a functional additive and a persulfate salt are added to the composite oxidation tank, and stirring is carried out at a room temperature and a rotation speed of 100-200 r / min for 3-4 h to obtain oxidation wastewater.

[0008] In the second step, the oxidation wastewater is filtered, and the filtrate is discharged after being detected to be qualified. The filtrate that does not meet the qualified standard is introduced into the composite oxidation tank for cyclic treatment.

[0009] The functional additive is a (3-carboxylpropyl)triphenylphosphonium bromide modified zeolite loaded with Pd / Fe.

[0010] Further, the functional additive is prepared by the following steps:

[0011] Step S1, the pretreated zeolite is added into (3-carboxylpropyl) triphenylphosphonium bromide aqueous solution, constant temperature oscillation at 40℃ for 48h, take out, vacuum drying at 60℃ to constant weight, to obtain modified zeolite;

[0012] Step S2, the modified zeolite is added into deionized water, under nitrogen protection, FeSO4·7H2O aqueous solution is added, stirring at 150r / min for 15-20min, KBH4 aqueous solution is added dropwise, after the end of dropwise addition, static 25-40min, potassium hexachloropalladate aqueous solution is added dropwise, after the end of dropwise addition, stirring under nitrogen protection for 15-25min, after the reaction is completed, filtration, the filter cake is washed with deionized water for 3-5 times, drying, to obtain functional additives.

[0013] With (3-carboxylpropyl) triphenylphosphonium bromide as modifier, (3-carboxylpropyl) triphenylphosphonium bromide is adsorbed on the surface of pretreated zeolite by cation exchange to form an adsorption layer, which improves the hydrophilic and lipophilic properties of the zeolite surface and improves the adsorption performance of the zeolite. Then, using the carboxyl group in (3-carboxylpropyl) triphenylphosphonium bromide and the oxygen-containing group in the pretreated zeolite as adsorption sites, KBH4 as a reducing agent, nano zero-valent iron is introduced on the surface of the modified zeolite, and finally a small amount of palladium is loaded on the surface of the nano zero-valent iron to form a nano bimetal, thereby obtaining the functional additives.

[0014] Further, the mass ratio of pretreated zeolite and (3-carboxylpropyl) triphenylphosphonium bromide in step S1 is 9-10:1.3-1.8, and the (3-carboxylpropyl) triphenylphosphonium bromide aqueous solution is composed of (3-carboxylpropyl) triphenylphosphonium bromide and deionized water according to 1g:100mL.

[0015] Further, the pretreated zeolite is prepared by the following steps:

[0016] The natural clinoptilolite is crushed and passed through a 10-20 mesh sieve, soaked in a nitric acid solution for 4-6h, taken out and washed with clean water to obtain the pretreated zeolite, and the concentration of the nitric acid solution is 1mol / L.

[0017] Further, the amount ratio of modified zeolite, deionized water, FeSO4·7H2O, KBH4 and potassium hexachloropalladate in step S2 is 10g:150-250mL:0.8-1.2g:0.46-0.52g:0.1-0.2, the FeSO4·7H2O aqueous solution is composed of FeSO4·7H2O and deionized water according to the amount ratio of 1g:5-10mL, the KBH4 aqueous solution is composed of KBH4 and deionized water according to the amount ratio of 1g:5-10mL, and the potassium hexachloropalladate aqueous solution is composed of potassium hexachloropalladate and deionized water according to the amount ratio of 1g:5-10mL.

[0018] Further, the persulfate salt is sodium peroxodisulfate and / or potassium hydrogen persulfate.

[0019] Further, in the first step, the pH adjustment uses dilute hydrochloric acid and sodium hydroxide.

[0020] Further, in the second step, the filtration uses a 0.2 mu m polytetrafluoroethylene (PTFE) filter membrane.

[0021] Further, the functional auxiliary agent is used in an amount of 0.03-0.13 Kg / L.

[0022] Further, the persulfate salt is used in an amount of 0.06-0.48 Kg / L.

[0023] Advantages of the present application:

[0024] The present application provides a treatment process for p-nitrochlorobenzene wastewater, which uses a functional auxiliary agent and a persulfate salt to treat wastewater containing p-nitrochlorobenzene, reduces the content of p-nitrochlorobenzene and phenolic organic matter in the wastewater by a high-level oxidation method, and effectively reduces the content of p-nitrochlorobenzene in the wastewater by reducing p-nitrochlorobenzene to an amine intermediate that is easy to degrade through the introduction of a functional auxiliary agent, and then oxidizing and degrading the amine intermediate using a persulfate salt.

[0025] The present application uses modified zeolite as a carrier, loads nanoscale zero-valent iron on the carrier, uses the chelation of the carboxyl group in 3-(carboxypropyl)triphenylphosphonium bromide to metal ions and the steric hindrance of the benzene ring to make the nanoparticles uniformly dispersed, makes the nanoscale zero-valent iron reduce and remove p-nitrochlorobenzene, and further improves the reduction effect by using the van der Waals force, electrostatic interaction, pi-pi interaction, hydrogen bonding, and ion exchange between the modified zeolite and organic pollutants.

[0026] The nanoscale zero-valent iron in the functional auxiliary agent of the present application can also activate the persulfate salt to generate free radicals, which further rapidly degrade and remove organic matter. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0028] Embodiment 1

[0029] The embodiment provides a functional aid, which is prepared through the following steps:

[0030] Step S1, 9g of pretreated zeolite is added into a solution composed of 1.3g of (3-carboxylpropyl)triphenylphosphonium bromide and 130mL of deionized water, constant temperature oscillation is carried out at 40℃ for 48h, and then the pretreated zeolite is taken out and vacuum dried at 60℃ until the weight is constant, so that modified zeolite is obtained;

[0031] Step S2, 10g of the modified zeolite is added into 150mL of deionized water, a solution composed of 0.8g of FeSO4·7H2O and 4mL of deionized water is added under nitrogen protection, and stirring is carried out at a rotating speed of 150r / min for 15min; then a solution composed of 0.46g of KBH4 and 4.6g of deionized water is added dropwise, after the dropwise addition is completed, the solution is kept still for 25min; then a solution composed of 0.1g of potassium hexachloropalladate and 1mL of deionized water is added dropwise, after the dropwise addition is completed, stirring is carried out under nitrogen protection for 15min; after the reaction is completed, filtration is carried out, the filter cake is washed with deionized water for 3 times, and then drying is carried out, so that the functional aid is obtained.

[0032] The pretreated zeolite is prepared through the following steps:

[0033] The natural clinoptilolite is crushed, passed through a 10-mesh sieve, soaked and washed in a nitric acid solution for 4h, and then taken out and washed with clean water, so that the pretreated zeolite is obtained, and the concentration of the nitric acid solution is 1mol / L.

[0034] Embodiment 2

[0035] The embodiment provides a functional aid, which is prepared through the following steps:

[0036] Step S1, 10g of pretreated zeolite is added into a solution composed of 1.8g of (3-carboxylpropyl)triphenylphosphonium bromide and 180mL of deionized water, constant temperature oscillation is carried out at 40℃ for 48h, and then the pretreated zeolite is taken out and vacuum dried at 60℃ until the weight is constant, so that modified zeolite is obtained;

[0037] Step S2, 10g of the modified zeolite is added into 250mL of deionized water, a solution composed of 1.2g of FeSO4·7H2O and 12mL of deionized water is added under nitrogen protection, and stirring is carried out at a rotating speed of 150r / min for 20min; then a solution composed of 0.52g of KBH4 and 5.2g of deionized water is added dropwise, after the dropwise addition is completed, the solution is kept still for 40min; then a solution composed of 0.2g of potassium hexachloropalladate and 2mL of deionized water is added dropwise, after the dropwise addition is completed, stirring is carried out under nitrogen protection for 25min; after the reaction is completed, filtration is carried out, the filter cake is washed with deionized water for 5 times, and then drying is carried out, so that the functional aid is obtained.

[0038] The pretreated zeolite is prepared through the following steps:

[0039] The natural clinoptilolite is crushed to pass through a 20-mesh screen, and is soaked in a nitric acid solution for 6 hours, and then is washed with clean water to obtain a pretreated zeolite. The concentration of the nitric acid solution is 1 mol / L.

[0040] Comparative Example 1

[0041] This comparative example provides a functional aid, which is prepared by the following steps:

[0042] Comparative Example 2

[0043] This comparative example provides a functional aid, which is prepared by the following steps:

[0044] 10 g of the modified zeolite is added to 150 mL of deionized water, and a solution composed of 0.8 g of FeSO4·7H2O and 4 mL of deionized water is added under nitrogen protection, and the solution is stirred at a speed of 150 r / min for 15 min, and a solution composed of 0.46 g of KBH4 and 4.6 g of deionized water is added dropwise, and after the dropwise addition is completed, the solution is left still for 25 min, and then is filtered, and the filter cake is washed with deionized water for 3 times, and is dried to obtain the functional aid. The preparation process of the modified zeolite is the same as that of Example 1.

[0045] Comparative Example 3

[0046] This comparative example provides a functional aid, which is prepared by the following steps:

[0047] 10 g of the pretreated zeolite is added to 250 mL of deionized water, and a solution composed of 1.2 g of FeSO4·7H2O and 12 mL of deionized water is added under nitrogen protection, and the solution is stirred at a speed of 150 r / min for 20 min, and a solution composed of 0.52 g of KBH4 and 5.2 g of deionized water is added dropwise, and after the dropwise addition is completed, the solution is left still for 40 min, and a solution composed of 0.2 g of potassium hexachloropalladate and 2 mL of deionized water is added dropwise, and after the dropwise addition is completed, the solution is stirred under nitrogen protection for 25 min, and then is filtered, and the filter cake is washed with deionized water for 5 times, and is dried to obtain the functional aid. The preparation process of the pretreated zeolite is the same as that of Example 1.

[0048] Example 3

[0049] A treatment process for p-nitrochlorobenzene wastewater, which comprises the following steps:

[0050] The first step, the p-nitrochlorobenzene wastewater is introduced into a composite oxidation tank, the pH of the p-nitrochlorobenzene wastewater is adjusted to 5 by using a 1 mol / L hydrochloric acid solution, the functional additive of example 1 and persulfate are added into the composite oxidation tank, the dosage of the functional additive is 0.03 Kg / L, the dosage of the persulfate is 0.06 Kg / L, under the condition of room temperature, the stirring speed is 100 r / min, and the stirring time is 3 h, and the oxidation wastewater is obtained;

[0051] The second step, the oxidation wastewater is filtered by using a 0.2 μm polytetrafluoroethylene filter membrane, the filtrate is discharged after being detected to be qualified, and the filtrate that does not reach the qualified standard is introduced into the composite oxidation tank for cyclic treatment.

[0052] The persulfate is sodium peroxodisulfate.

[0053] Example 4

[0054] A treatment process of p-nitrochlorobenzene wastewater, including the following steps:

[0055] The first step, the p-nitrochlorobenzene wastewater is introduced into a composite oxidation tank, the pH of the p-nitrochlorobenzene wastewater is adjusted to 5 by using a 1 mol / L hydrochloric acid solution, the functional additive of example 2 and persulfate are added into the composite oxidation tank, the dosage of the functional additive is 0.08 Kg / L, the dosage of the persulfate is 0.28 Kg / L, under the condition of room temperature, the stirring speed is 150 r / min, and the stirring time is 3.5 h, and the oxidation wastewater is obtained;

[0056] The second step, the oxidation wastewater is filtered by using a 0.2 μm polytetrafluoroethylene filter membrane, the filtrate is discharged after being detected to be qualified, and the filtrate that does not reach the qualified standard is introduced into the composite oxidation tank for cyclic treatment.

[0057] The persulfate is potassium hydrogen persulfate.

[0058] Example 5

[0059] A treatment process of p-nitrochlorobenzene wastewater, including the following steps:

[0060] The first step, the p-nitrochlorobenzene wastewater is introduced into a composite oxidation tank, the pH of the p-nitrochlorobenzene wastewater is adjusted to 5 by using a 1 mol / L hydrochloric acid solution, the functional additive of example 1 and persulfate are added into the composite oxidation tank, the dosage of the functional additive is 0.13 Kg / L, the dosage of the persulfate is 0.48 Kg / L, under the condition of room temperature, the stirring speed is 200 r / min, and the stirring time is 4 h, and the oxidation wastewater is obtained;

[0061] The second step, the oxidation wastewater is filtered by using a 0.2 μm polytetrafluoroethylene filter membrane, the filtrate is discharged after being detected to be qualified, and the filtrate that does not reach the qualified standard is introduced into the composite oxidation tank for cyclic treatment.

[0062] The persulfate salt is composed of sodium peroxodisulfate and potassium hydrogen persulfate in a mass ratio of 1:1.

[0063] Comparative Example 4

[0064] A treatment process for p-nitrochlorobenzene wastewater, compared with Example 3, the functional adjuvant in Example 3 is replaced by the product prepared in Comparative Example 1, and the remaining raw materials and preparation process are the same as in Example 3.

[0065] Comparative Example 5

[0066] A treatment process for p-nitrochlorobenzene wastewater, compared with Example 3, the functional adjuvant in Example 3 is replaced by the product prepared in Comparative Example 2, and the remaining raw materials and preparation process are the same as in Example 3.

[0067] Comparative Example 6

[0068] A treatment process for p-nitrochlorobenzene wastewater, compared with Example 3, the functional adjuvant in Example 3 is replaced by the product prepared in Comparative Example 3, and the remaining raw materials and preparation process are the same as in Example 3.

[0069] The treatment process described in Examples 3-5 and Comparative Examples 4-6 is used to treat p-nitrochlorobenzene wastewater from a chemical plant in Dongzhi County, Anhui Province. The pH of the raw p-nitrochlorobenzene wastewater is 12.8, the content of p-nitrochlorobenzene is 759 mg / L, the content of nitrochlorobenzene phenol is 354 mg / L, and the content of nitrophenol is 158 mg / L. After treatment, the contents of p-nitrochlorobenzene, nitrochlorobenzene phenol and nitrophenol in the filtrate were detected, and the results are shown in Table 1:

[0070] Table 1

[0071]

[0072]

[0073] As can be seen from the data recorded in Table 1, the treatment process described in Examples 3-5 has better treatment effect on p-nitrochlorobenzene wastewater than Comparative Examples 4-6.

[0074] It should be noted that in this document, relational terms such as first and second and the like can only be used to distinguish one entity or action from another entity or action, without necessarily requiring or implying that there is any such actual relationship or order between these entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof are intended to cover non-exclusive inclusions, so that a process, method, article, or apparatus that includes a list of elements does not only include those elements, but also includes other elements not explicitly listed, or other elements inherent to such a process, method, article, or apparatus.

[0075] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A treatment process for p-nitrochlorobenzene wastewater, characterized in that, Includes the following steps: Step 1: Pass the p-nitrochlorobenzene wastewater into the composite oxidation tank, adjust the pH of the p-nitrochlorobenzene wastewater to 5-6, add functional additives and persulfate to the composite oxidation tank, stir for 3-4 hours to obtain oxidized wastewater; The second step is to filter the oxidation wastewater. The filtrate is discharged after passing the test, while the filtrate that does not meet the standard is introduced into the composite oxidation tank for recycling. The functional additive is a Pd / Fe-loaded (3-carboxypropyl)triphenylphosphine bromide modified zeolite; Functional additives are prepared through the following steps: Step S1: Add the pretreated zeolite to an aqueous solution of (3-carboxypropyl)triphenylphosphine bromide, shake at 40°C for 48 hours, remove and vacuum dry at 60°C to constant weight to obtain modified zeolite; Step S2: Add the modified zeolite to deionized water. Under nitrogen protection, add FeSO4·7H2O aqueous solution and stir for 15-20 min. Add KBH4 aqueous solution dropwise. After the addition is complete, let stand for 25-40 min. Add potassium hexachloropalladium aqueous solution dropwise. After the addition is complete, stir for 15-25 min under nitrogen protection. After the reaction is complete, filter. Wash the filter cake with deionized water 3-5 times and dry to obtain the functional additive.

2. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, In step S1, the mass ratio of pretreated zeolite to (3-carboxypropyl)triphenylphosphine bromide is 9-10:1.3-1.

8.

3. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, Pretreated zeolite is prepared through the following steps: Natural clinoptilolite was crushed and passed through a 10-20 mesh sieve. It was then soaked and washed in nitric acid solution for 4-6 hours, and rinsed with clean water to obtain pretreated zeolite. The concentration of the nitric acid solution was 1 mol / L.

4. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, In step S2, the ratio of modified zeolite, deionized water, FeSO4·7H2O, KBH4 and potassium hexachloropalladate is 10g: 150-250mL: 0.8-1.2g: 0.46-0.52g: 0.1-0.

2.

5. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, The persulfate is sodium persulfate and / or potassium peroxymonosulfate.

6. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, The dosage of functional additives is 0.03-0.13 kg / L.

7. The treatment process for p-nitrochlorobenzene wastewater according to claim 1, characterized in that, The dosage of persulfate is 0.06-0.48 kg / L.

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