A treatment process for p-nitrochlorobenzene production wastewater
By synergistically interacting humic/montmorillonite/zinc oxide composite material with persulfate under ultraviolet light, a strong oxidizing free radical is generated, which solves the problem of difficult degradation of p-nitrochlorobenzene production wastewater and achieves efficient and stable degradation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI DONGZHI GUANGXIN AGROCHEMICAL CO LTD
- Filing Date
- 2025-11-24
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies are insufficient for efficiently degrading wastewater from the production of p-nitrochlorobenzene, and physicochemical adsorption methods are incomplete and prone to causing secondary pollution.
A synergistic effect between a humic/montmorillonite/zinc oxide composite material and persulfate under ultraviolet light irradiation generates highly oxidizing free radicals, which achieve efficient degradation of p-nitrochlorobenzene through π-π conjugation effect and photogenerated electron conduction.
It significantly improves the degradation rate and overall treatment efficiency of p-nitrochlorobenzene, avoids the problem of easy deactivation of a single catalytic pathway, and ensures the long-term stability of the system.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment technology, and in particular to a treatment process for wastewater from the production of p-nitrochlorobenzene. Background Technology
[0002] p-Nitrochlorobenzene is a key organic chemical intermediate widely used in the preparation of various industrial products such as pesticides, rubber, and preservatives. However, this substance poses significant risks to human health and the ecological environment. Studies have shown that p-nitrochlorobenzene can cause methemoglobinemia and anemia; multiple studies have also indicated that it may be a genotoxin and a suspected carcinogen, thus it has been listed as a priority toxic pollutant for control by the U.S. Environmental Protection Agency (EPA), the European Union, and China, exhibiting clear carcinogenic, teratogenic, and mutagenic effects and genotoxicity.
[0003] From a molecular structure perspective, p-nitrochlorobenzene contains both a nitro group and a chlorine atom, both of which are strong electron-withdrawing groups. This significantly reduces the electron cloud density of the benzene ring, making the compound extremely chemically stable and difficult to degrade naturally in the environment, thus causing it to persist for a long time. Furthermore, p-nitrochlorobenzene strongly inhibits the enzyme systems and cell membranes of microorganisms, leading to a decrease in the activity of the electron transport system (ETS), severely hindering microbial growth and the metabolism of organic matter, making it difficult to effectively degrade using conventional biological methods.
[0004] Currently, the treatment of wastewater from p-nitrochlorobenzene production still faces technical challenges, lacking highly efficient treatment processes. For example, physicochemical adsorption methods not only fail to completely remove p-nitrochlorobenzene but also easily cause secondary pollution. Therefore, there is an urgent need for a highly efficient treatment process to degrade p-nitrochlorobenzene production wastewater. Summary of the Invention
[0005] The purpose of this invention is to provide a treatment process for wastewater from the production of p-nitrochlorobenzene, so as to efficiently degrade p-nitrochlorobenzene.
[0006] This invention provides a treatment process for wastewater from the production of p-nitrochlorobenzene, comprising the following steps: S1. Filter the wastewater from the production of p-nitrochlorobenzene to remove suspended solids and obtain a preliminary purified liquid; S2. Adjust the pH of the preliminary purified liquid to 5-6 in the equalization tank, then add humic / montmorillonite / zinc oxide composite material and persulfate, irradiate with ultraviolet light and stir for 1-2 hours to obtain oxidized wastewater; S3. The oxidation wastewater is subjected to solid-liquid separation, and the separated liquid is discharged after meeting the qualified standards.
[0007] By adopting the above technical solution, the wastewater containing p-nitrochlorobenzene is first filtered to remove suspended solid particles, creating favorable conditions for subsequent treatment; secondly, the pH is adjusted to a weakly acidic environment of 5-6 to provide optimal reaction conditions for the subsequent oxidation process; finally, the humic / montmorillonite / zinc oxide composite material is used in conjunction with persulfate to generate strong oxidizing free radicals under ultraviolet light irradiation, achieving efficient degradation of p-nitrochlorobenzene.
[0008] Specifically, the humic material / montmorillonite / zinc oxide composite material possesses multiple functions. Montmorillonite provides a good carrier structure and adsorption performance; humic material promotes electron transfer and enhances catalytic activity; zinc oxide generates freely moving electron-hole pairs under UV excitation, synergistically producing sulfate and hydroxyl radicals with persulfate. Persulfate is activated under UV irradiation and material catalysis, generating highly oxidizing sulfate radicals that effectively attack the benzene ring in the p-nitrochlorobenzene molecule, achieving ring-opening degradation. Furthermore, persulfate can attack the unsaturated bonds in humic material to generate intermediates that can initiate the production of hydroxyl radicals, accelerating the removal rate of p-nitrochlorobenzene.
[0009] Preferably, the humus / montmorillonite / zinc oxide composite material is obtained by the following method: A1. Add glucose, glycine and catechol to deionized water, mix well, add pretreated montmorillonite, sonicate for 8-15 hours, filter, wash and dry to obtain humic / montmorillonite complex. A2. Disperse the humic substance / montmorillonite complex in deionized water, add dopamine while adding buffer solution, stir for 30-50 hours, centrifuge and dry to obtain dopamine / humic substance / montmorillonite complex. A3. Dissolve hexadecyltrimethylammonium bromide and zinc acetate dihydrate in ethanol, stir at 80-90°C for 1-2 hours, add potassium hydroxide and dopamine / humic acid / montmorillonite complex, stir for 6-8 hours, filter and dry to obtain the product.
[0010] By employing the above technical solution, humic substances are first generated in situ on montmorillonite. Glucose, glycine, and catechol undergo Maillard and polymerization reactions under hydrothermal conditions to form a humic-like structure rich in functional groups. Then, dopamine is polymerized under alkaline conditions to form polydopamine. Polydopamine not only anchors and encapsulates on the montmorillonite surface, forming a robust organic hybrid layer to prevent humic substances from being lost in subsequent steps or during use, but also, the abundant amino and phenolic hydroxyl groups in the polydopamine layer serve as excellent coordination and nucleation sites, effectively capturing and stabilizing zinc ions in solution, guiding the uniform and dense growth of zinc oxide nanoparticles, and preventing their aggregation. Furthermore, the benzene ring on the polydopamine molecule can generate a very strong π-π conjugation effect with the benzene ring on p-nitrochlorobenzene, enriching pollutants around the catalytically active site and improving the degradation efficiency of p-nitrochlorobenzene through the proximity effect. Finally, zinc acetate was hydrolyzed on the dopamine / humic material / montmorillonite complex under alkaline conditions to generate zinc oxide nanoparticles in situ, forming a humic material / montmorillonite / zinc oxide composite material.
[0011] Preferably, in step A1, the pretreated montmorillonite is prepared by the following method: Disperse dried montmorillonite in deionized water, sonicate for 30-60 minutes, add ferric chloride, stir, wash, and dry to obtain the final product.
[0012] Preferably, in step A1, the ratio of glucose, glycine, catechol, deionized water and pretreated montmorillonite is 0.01 mol: 0.01 mol: 0.01 mol: 200 mL: (3-5) g.
[0013] Preferably, in step A2, the ratio of humic substance / montmorillonite complex, deionized water, buffer solution and dopamine is (3-5) g: 100 mL: 200 mL: (1-2) g.
[0014] Preferably, in step A2, the buffer solution is Tris-HCl with a pH of 8.5.
[0015] Preferably, in step A3, the ratio of dopamine / humic acid / montmorillonite complex, hexadecyltrimethylammonium bromide, ethanol, zinc acetate dihydrate and potassium hydroxide is 1g: (5-6)g: 150mL: (3-4)g: (0.5-1)g.
[0016] Preferably, in step S2, the persulfate includes permonosulfate and / or perdisulfate.
[0017] Preferably, in step S2, the amount of humus / montmorillonite / zinc oxide composite material is 0.01 to 0.1 kg / L.
[0018] Preferably, in step S2, the amount of persulfate used is 0.02 to 0.3 kg / L.
[0019] Preferably, the wavelength of the ultraviolet light is 365nm and the irradiation time is 90-120min.
[0020] The beneficial effects of this invention are: 1. This invention, through the use of a humic / montmorillonite / zinc oxide composite material, not only specifically adsorbs and enriches p-nitrochlorobenzene molecules through a strong π-π conjugation effect, but also greatly promotes the conduction of photogenerated electrons. It achieves an organic combination of targeted adsorption and in-situ catalysis, directly delivering pollutants to the catalytically active sites. This solves the core problem of low efficiency in free radical-pollutant interactions due to random collisions, significantly improving the degradation rate and overall treatment efficiency.
[0021] 2. This process cleverly couples photocatalysis, persulfate activation, and a heterogeneous Fenton-like reaction. Zinc oxide generates electron-hole pairs under ultraviolet light; pre-loaded iron centers form a catalytic cycle, continuously activating persulfate; simultaneously, persulfate can attack unsaturated bonds in humic substances, generating new free radical precursors, thus creating a stable and high-concentration free radical environment. This not only efficiently breaks the stable benzene ring of p-nitrochlorobenzene but also avoids the disadvantage of easy deactivation in single catalytic pathways, ensuring the long-term operational stability of the system. Detailed Implementation
[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.
[0023] A treatment process for wastewater from the production of p-nitrochlorobenzene includes the following steps: S1. Filter the wastewater from the production of p-nitrochlorobenzene to remove suspended solids and obtain a preliminary purified liquid; S2. Adjust the pH of the preliminary purified liquid to 5-6 in the equalization tank, then add humic / montmorillonite / zinc oxide composite material and persulfate, irradiate with ultraviolet light and stir for 1-2 hours to obtain oxidized wastewater; S3. The oxidation wastewater is subjected to solid-liquid separation, and the separated liquid is discharged after meeting the qualified standards.
[0024] By adopting the above technical solution, the wastewater containing p-nitrochlorobenzene is first filtered to remove suspended solid particles, creating favorable conditions for subsequent treatment; secondly, the pH is adjusted to a weakly acidic environment of 5-6 to provide optimal reaction conditions for the subsequent oxidation process; finally, the humic / montmorillonite / zinc oxide composite material is used in conjunction with persulfate to generate strong oxidizing free radicals under ultraviolet light irradiation, achieving efficient degradation of p-nitrochlorobenzene.
[0025] Specifically, the humic material / montmorillonite / zinc oxide composite material possesses multiple functions. Montmorillonite provides a good carrier structure and adsorption performance; humic material promotes electron transfer and enhances catalytic activity; zinc oxide generates photogenerated electron-hole pairs under ultraviolet light excitation, synergistically producing sulfate radicals and hydroxyl radicals with persulfate. Persulfate is activated under ultraviolet light irradiation and material catalysis, generating highly oxidizing sulfate radicals that can effectively attack the benzene ring in the p-nitrochlorobenzene molecule, achieving ring-opening degradation. In addition, persulfate can also attack the unsaturated bonds in humic material to generate intermediates that can initiate the production of hydroxyl radicals, accelerating the removal rate of p-nitrochlorobenzene.
[0026] In some embodiments, the humus / montmorillonite / zinc oxide composite material is obtained by the following method: A1. Add glucose, glycine and catechol to deionized water, mix well, add pretreated montmorillonite, sonicate for 8-15 hours, filter, wash and dry to obtain humic / montmorillonite complex. A2. Disperse the humic substance / montmorillonite complex in deionized water, add dopamine while adding buffer solution, stir for 30-50 hours, centrifuge and dry to obtain dopamine / humic substance / montmorillonite complex. A3. Dissolve hexadecyltrimethylammonium bromide and zinc acetate dihydrate in ethanol, stir at 80-90°C for 1-2 hours, add potassium hydroxide and dopamine / humic acid / montmorillonite complex, stir for 6-8 hours, filter and dry to obtain the product.
[0027] By employing the above technical solution, humic substances are first generated in situ on montmorillonite. Glucose, glycine, and catechol undergo Maillard and polymerization reactions under hydrothermal conditions to form a humic-like structure rich in functional groups. Then, dopamine is polymerized under alkaline conditions to form polydopamine. Polydopamine not only anchors and encapsulates on the montmorillonite surface, forming a robust organic hybrid layer to prevent humic substances from being lost in subsequent steps or during use, but also, the abundant amino and phenolic hydroxyl groups in the polydopamine layer serve as excellent coordination and nucleation sites, effectively capturing and stabilizing zinc ions in solution, guiding the uniform and dense growth of zinc oxide nanoparticles, and preventing their aggregation. Furthermore, the benzene ring on the polydopamine molecule can generate a very strong π-π conjugation effect with the benzene ring on p-nitrochlorobenzene, enriching pollutants around the catalytically active site and improving the degradation efficiency of p-nitrochlorobenzene through the proximity effect. Finally, zinc acetate was hydrolyzed on the dopamine / humic material / montmorillonite complex under alkaline conditions to generate zinc oxide nanoparticles in situ, forming a humic material / montmorillonite / zinc oxide composite material.
[0028] In some embodiments, in step A1, the pretreated montmorillonite is prepared by the following method: Disperse dried montmorillonite in deionized water, sonicate for 30-60 minutes, add ferric chloride, stir, wash, and dry to obtain the final product.
[0029] By adopting the above technical solutions, introducing more ferric ions into the interlayer of montmorillonite can improve the efficiency of the subsequent polyphenol-Maillard reaction between glucose, glycine, and catechol, causing it to condense in situ on the surface and interlayer of montmorillonite, generating a humic layer rich in quinone groups and phenolic hydroxyl groups. In addition, the introduction of more ferric ions can also be reduced to ferrous iron by subsequent persulfate, and the ferrous iron can then undergo a redox reaction with persulfate to generate sulfate radicals and ferric iron, thereby achieving efficient degradation of p-nitrochlorobenzene.
[0030] In some embodiments, in step A1, the ratio of glucose, glycine, catechol, deionized water, and pretreated montmorillonite is 0.01 mol: 0.01 mol: 0.01 mol: 200 mL: (3-5) g; humic substances can be generated by utilizing glucose, glycine, and catechol, wherein glucose provides a carbon source, glycine provides a nitrogen source, and catechol provides phenolic hydroxyl groups; the above-mentioned ratio can generate humic substances on the surface and between layers of montmorillonite, ensuring sufficient active sites.
[0031] In some embodiments, in step A2, the ratio of humic / montmorillonite complex, deionized water, buffer solution and dopamine is (3-5) g: 100 mL: 200 mL: (1-2) g; this ratio ensures that dopamine can form a complete and uniform polydopamine coating layer on the surface of the humic / montmorillonite complex, while avoiding pore blockage caused by excessive polymerization of dopamine.
[0032] In some embodiments, in step A2, the buffer solution is Tris-HCl with a pH of 8.5; this buffer solution facilitates the oxidative self-polymerization of dopamine to form a stable polydopamine layer without damaging the structure of the humic / montmorillonite complex.
[0033] In some embodiments, in step A3, the ratio of dopamine / humic acid / montmorillonite complex, hexadecyltrimethylammonium bromide, ethanol, zinc acetate dihydrate, and potassium hydroxide is 1g:(5-6)g:150mL:(3-4)g:(0.5-1)g; zinc acetate dihydrate is hydrolyzed in an alkaline environment to generate zinc oxide nanoparticles. This ratio ensures that zinc oxide is uniformly distributed on the material surface in the form of nanoscale particles, which not only ensures sufficient photocatalytic activity but also avoids the decrease in activity caused by excessively large particles.
[0034] In some embodiments, in step S2, the persulfate includes monosulfate and / or perdisulfate; the persulfate can not only generate highly oxidizing sulfate radicals to degrade p-chlorophenol under ultraviolet light and material catalysis, but also attack the unsaturated bonds in humic substances to generate intermediate products that can initiate the generation of hydroxyl radicals, thereby accelerating the removal rate of p-nitrochlorobenzene.
[0035] In some embodiments, in step S2, the amount of humus / montmorillonite / zinc oxide composite material is 0.01 to 0.1 kg / L; this dosage range can control material costs while ensuring treatment effectiveness.
[0036] In some embodiments, in step S2, the amount of persulfate used is 0.02 to 0.3 kg / L; this range of amounts can provide a sufficient concentration of oxidant to ensure the complete degradation of p-nitrochlorobenzene, while avoiding waste of oxidant and secondary pollution.
[0037] In some embodiments, the wavelength of the ultraviolet light is 365 nm, and the irradiation time is 90–120 min; this wavelength matches the band gap width of zinc oxide, which can effectively excite photogenerated electron-hole pairs, and this irradiation time can ensure the full degradation of p-nitrochlorobenzene.
[0038] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0039] Preparation Example
[0040] Preparation Example 1: A humus / montmorillonite / zinc oxide composite material was obtained by the following method: A1. Disperse 1g of dried montmorillonite in deionized water, sonicate for 60 minutes, add 0.3g of ferric chloride, stir, wash, and dry to obtain the final product. A2. Add 0.01 mol glucose, 0.01 mol glycine and 0.01 mol catechol to 200 mL of deionized water, mix well, add 4 g of pretreated montmorillonite, sonicate for 15 h, filter, wash and dry to obtain humic / montmorillonite complex. A3. Disperse 4g of humic substance / montmorillonite complex into 100mL of deionized water, add 200mL of Tris-HCl buffer with pH 8.5, and add 1.2g of dopamine. Stir for 50h, centrifuge and dry to obtain dopamine / humic substance / montmorillonite complex. A4. Dissolve 5.5g of cetyltrimethylammonium bromide and 4g of zinc acetate dihydrate in 150mL of ethanol. Stir at 90°C for 1h, then add 0.7g of potassium hydroxide and 1g of dopamine / humic acid / montmorillonite composite. Stir for 8h, filter and dry to obtain a humic acid / montmorillonite / zinc oxide composite material.
[0041] Preparation Example 2 is a humus / montmorillonite / zinc oxide composite material, which differs from Preparation Example 1 only in that the montmorillonite is not pretreated with ferric chloride.
[0042] Preparation Example 3: A humus / montmorillonite / zinc oxide composite material was obtained by the following method: A1. Disperse 1g of dried montmorillonite in deionized water, sonicate for 60 minutes, add 0.3g of ferric chloride, stir, wash, and dry to obtain the final product. A2. Disperse 4g of pretreated montmorillonite in 100mL of deionized water, add 200mL of Tris-HCl buffer solution with pH 8.5, and add 1.2g of dopamine. Stir for 50h, centrifuge and dry to obtain dopamine / humic substance / montmorillonite complex. A3. Dissolve 5.5g of cetyltrimethylammonium bromide and 4g of zinc acetate dihydrate in 150mL of ethanol. Stir at 90°C for 1h, then add 0.7g of potassium hydroxide and 1g of dopamine / humic acid / montmorillonite composite. Stir for 8h, filter and dry to obtain a humic acid / montmorillonite / zinc oxide composite material.
[0043] Preparation Example 4: A humus / montmorillonite / zinc oxide composite material was obtained by the following method: A1. Disperse 1g of dried montmorillonite in deionized water, sonicate for 60 minutes, add 0.3g of ferric chloride, stir, wash, and dry to obtain the final product. A2. Add 0.01 mol glucose, 0.01 mol glycine and 0.01 mol catechol to 200 mL of deionized water, mix well, add 4 g of pretreated montmorillonite, sonicate for 15 h, filter, wash and dry to obtain humic / montmorillonite complex. A3. Dissolve 5.5g of cetyltrimethylammonium bromide and 4g of zinc acetate dihydrate in 150mL of ethanol. Stir at 90°C for 1h, then add 0.7g of potassium hydroxide and 1g of humic / montmorillonite composite. Stir for 8h, filter and dry to obtain a humic / montmorillonite / zinc oxide composite material.
[0044] Preparation Example 5: A humus / montmorillonite / zinc oxide composite material was obtained by the following method: A1. Disperse 1g of dried montmorillonite in deionized water, sonicate for 60 minutes, add 0.3g of ferric chloride, stir, wash, and dry to obtain the final product. A2. Add 0.01 mol glucose, 0.01 mol glycine and 0.01 mol catechol to 200 mL of deionized water, mix well, add 4 g of pretreated montmorillonite, sonicate for 15 h, filter, wash and dry to obtain humic / montmorillonite complex. A3. Disperse 4g of humic / montmorillonite complex into 100mL of deionized water, add 200mL of Tris-HCl buffer with pH 8.5, and add 1.2g of dopamine. Stir for 50h, centrifuge and dry to obtain dopamine / humic / montmorillonite complex.
[0045] Example
[0046] Example 1: A treatment process for wastewater from the production of p-nitrochlorobenzene, comprising the following steps: S1. Filter the wastewater from the production of p-nitrochlorobenzene to remove suspended solids and obtain a preliminary purified liquid; S2. The pH of the preliminary purified liquid was adjusted to 5 in the equalization tank with 1M hydrochloric acid solution. Then, the humic / montmorillonite / zinc oxide composite material prepared in Preparation Example 1 and persulfate were added to it. The mixture was irradiated with ultraviolet light at a wavelength of 365nm for 2 hours and stirred for 2 hours to obtain oxidized wastewater. S3. The oxidation wastewater is subjected to solid-liquid separation. The separated liquid is discharged after meeting the qualified standards, and the filtrate that does not meet the qualified standards is re-entered into the equalization tank for treatment. The amount of humus / montmorillonite / zinc oxide composite material used was 0.02 kg / L; the amount of persulfate used was 0.04 kg / L.
[0047] Example 2, a treatment process for wastewater from the production of p-nitrochlorobenzene, differs from Example 1 only in that the amount of humic / montmorillonite / zinc oxide composite material used is 0.05 kg / L.
[0048] Comparative Example
[0049] Comparative Example 1, a treatment process for wastewater from the production of p-nitrochlorobenzene, differs from Example 1 only in that the humic / montmorillonite / zinc oxide composite material prepared in Preparation Example 2 of the same mass is used to replace the humic / montmorillonite / zinc oxide composite material in Example 1.
[0050] Comparative Example 2, a treatment process for wastewater from the production of p-nitrochlorobenzene, differs from Example 1 only in that the humic / montmorillonite / zinc oxide composite material prepared in Preparation Example 3 of the same mass is used to replace the humic / montmorillonite / zinc oxide composite material in Example 1.
[0051] Comparative Example 3, a treatment process for wastewater from the production of p-nitrochlorobenzene, differs from Example 1 only in that the humic / montmorillonite / zinc oxide composite material prepared in Preparation Example 4 is used instead of the humic / montmorillonite / zinc oxide composite material in Example 1.
[0052] Comparative Example 4, a treatment process for wastewater from the production of p-nitrochlorobenzene, differs from Example 1 only in that the humic / montmorillonite / zinc oxide composite material prepared in Preparation Example 5 is used to replace the humic / montmorillonite / zinc oxide composite material in Example 1 with the same mass.
[0053] Performance testing
[0054] The treatment processes described in Examples 1-2 and Comparative Examples 1-4 were used to treat nitrochlorobenzene wastewater from a chemical plant in Dongzhi County, Anhui Province. The original nitrochlorobenzene wastewater had a pH of 11.6 and a nitrochlorobenzene content of 783 mg / L. After treatment, the nitrochlorobenzene content in the filtrate was measured, and the results are shown in Table 1. Table 1 Performance test results
[0055] According to Table 1, and considering both Example 1 and Comparative Example 1, it can be seen that the p-nitrochlorobenzene content in Comparative Example 1 is higher than that in Example 1. This is because Comparative Example 1 did not pretreat the montmorillonite with ferric chloride, resulting in insufficient iron active sites in the humic / montmorillonite / zinc oxide composite material. This not only reduces the catalytic efficiency of the material for the polyphenol-Maillard reaction between glucose, glycine, and catechol, affecting the quality of humic layer formation, but more importantly, it prevents the subsequent photocatalytic process from utilizing Fe... 3+ / Fe 2+ The continuous activation of persulfate in the cycle leads to insufficient generation of sulfate free radicals, thereby reducing the degradation efficiency of p-nitrochlorobenzene.
[0056] Combining Example 1 and Comparative Example 2, it can be seen that the p-nitrochlorobenzene content in Comparative Example 2 is higher than that in Example 1. This is because Comparative Example 2 did not generate humic substances in situ on montmorillonite, resulting in the material lacking the abundant functional groups and quinone structures provided by humic substances. This is detrimental to the material's ability to promote electron transfer, affecting the effective utilization of photogenerated electrons, and also reducing the sites for persulfate to attack unsaturated bonds and generate hydroxyl radical precursors, leading to poor degradation performance.
[0057] Combining Example 1 and Comparative Example 3, it can be seen that the p-nitrochlorobenzene content in Comparative Example 3 is higher than that in Example 1. The reason is that the montmorillonite in Comparative Example 3 is not loaded with dopamine, thus lacking the strong adsorption sites and efficient electron shuttle channels provided by polydopamine, which weakens the pollutant enrichment effect, hinders the transmission of photogenerated electrons, and affects the performance of the adsorption-catalysis synergistic effect.
[0058] Combining Example 1 and Comparative Example 4, it can be seen that the p-nitrochlorobenzene content in Comparative Example 4 is higher than that in Example 1. This is because zinc oxide was not formed on the montmorillonite in Comparative Example 4, thus preventing the generation of photogenerated electron-hole pairs under ultraviolet light irradiation. This not only leads to the failure of the photocatalytic radical generation pathway but also reduces the Fe content in the entire system. 3+ / Fe 2+ The insufficient driving force of the cycle due to photogenerated electrons leads to low activation efficiency of persulfate, insufficient number of free radicals, and difficulty in effectively degrading p-nitrochlorobenzene.
[0059] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A treatment process for wastewater from the production of p-nitrochlorobenzene, characterized in that, Includes the following steps: S1. Filter the wastewater from the production of p-nitrochlorobenzene to remove suspended solids and obtain a preliminary purified liquid; S2. Adjust the pH of the preliminary purified liquid to 5-6 in the equalization tank, then add humic / montmorillonite / zinc oxide composite material and persulfate, irradiate with ultraviolet light and stir for 1-2 hours to obtain oxidized wastewater; S3. The oxidation wastewater is subjected to solid-liquid separation, and the separated liquid is discharged after meeting the qualified standards. The humus / montmorillonite / zinc oxide composite material was obtained by the following method: A1. Add glucose, glycine and catechol to deionized water, mix well, add pretreated montmorillonite, sonicate for 8-15 hours, filter, wash and dry to obtain humic / montmorillonite complex. A2. Disperse the humic substance / montmorillonite complex in deionized water, add dopamine while adding buffer solution, stir for 30-50 hours, centrifuge and dry to obtain dopamine / humic substance / montmorillonite complex. A3. Dissolve hexadecyltrimethylammonium bromide and zinc acetate dihydrate in ethanol, stir at 80-90°C for 1-2 hours, add potassium hydroxide and dopamine / humic acid / montmorillonite complex, stir for 6-8 hours, filter and dry to obtain the product; In step A1, the pretreated montmorillonite is prepared by the following method: Disperse dried montmorillonite in deionized water, ultrasonically disperse for 30-60 minutes, add ferric chloride, stir, wash, and dry to obtain the final product. In step A2, the buffer solution is Tris-HCl with a pH of 8.
5.
2. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step A1, the ratio of glucose, glycine, catechol, deionized water and pretreated montmorillonite is 0.01 mol: 0.01 mol: 0.01 mol: 200 mL: (3-5) g.
3. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step A2, the ratio of the amount of humic substance / montmorillonite complex, deionized water, buffer solution and dopamine is (3-5) g: 100 mL: 200 mL: (1-2) g.
4. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step A3, the ratio of the dopamine / humic substance / montmorillonite complex, hexadecyltrimethylammonium bromide, ethanol, zinc acetate dihydrate and potassium hydroxide is 1g: (5-6)g: 150mL: (3-4)g: (0.5-1)g.
5. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step S2, the persulfate includes permonosulfate and / or perdisulfate.
6. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step S2, the amount of the humus / montmorillonite / zinc oxide composite material is 0.01 to 0.1 kg / L.
7. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step S2, the amount of persulfate used is 0.02 to 0.3 kg / L.
8. The treatment process for wastewater from the production of p-nitrochlorobenzene according to claim 1, characterized in that, In step S2, the wavelength of the ultraviolet light is 365nm, and the irradiation time is 90-120min.