Method for treating perchlorate-containing wastewater

Abstract

The invention belongs to the technical field of wastewater treatment, and provides a method for treating wastewater containing perchlorate, which comprises the following steps of: adding mixed quaternary ammonium salt into the wastewater, reacting the mixed quaternary ammonium salt with the perchlorate in the industrial wastewater to generate perchlorate quaternary ammonium salt precipitate, and filtering to remove the perchlorate quaternary ammonium salt in the wastewater to realize the enrichment of the perchlorate, the perchlorate in the industrial wastewater can be reduced to 0.02 mg / L or below. According to the process provided by the invention, the perchlorate in the wastewater is directly recycled in the form of the perchlorate quaternary ammonium salt precipitate, and the recycled perchlorate quaternary ammonium salt precipitate can be used as an oxidant for producing fireworks, so that the perchlorate quaternary ammonium salt is reused, and high-added-value recycling is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a method for treating wastewater containing perchlorate and recycling of quaternary ammonium perchlorate. BACKGROUND

[0002] Perchlorate is a stable inorganic compound that is ubiquitous in nature, mainly including potassium perchlorate, sodium perchlorate and lithium perchlorate. Perchlorate in the environment is mainly derived from artificial synthesis, and is widely used in the fields of fireworks manufacturing, solid propellants for producing rocket and missile engines, and military industry due to its strong oxidizing property. At the same time, perchlorate is often used as an important chemical reagent in analytical chemistry and in industries such as metal extraction, rubber manufacturing, leather processing, paint production, lubricating oil and feed additive, etc. Due to natural and artificial pollution, a large amount of perchlorate enters the natural environment, causing pollution. Perchlorate is one of the main inorganic pollutants in the environment. Most perchlorates exist in solid state and are relatively easy to dissolve in water, and belong to non-volatile inorganic salts. After dissolution, perchlorate is stable, and in perchlorate molecule (ClO4 - ), four oxygen atoms are directly connected to chlorine atom, and the tetrahedral structure makes it have high chemical stability and good mobility, so it is difficult to be degraded and can remain in surface or underground water environment for decades. As an endocrine disruptor, perchlorate can affect the function of human thyroid, competitively inhibit and hinder the absorption of iodine by thyroid, thereby causing the decrease and deficiency of thyroid hormone production and affecting the metabolic function, especially the normal development of newborn fetus.

[0003] Due to the physical properties of perchlorate (low volatility, strong stability and high solubility), conventional water treatment technologies (air washing and advanced oxidation) cannot effectively remove perchlorate in water, and the treatment effect is not ideal. At present, the treatment methods used for removal or pollution remediation include chemical precipitation, ion exchange resin method, microbial treatment method, membrane separation technology, activated carbon adsorption method and chemical reduction method, etc.

[0004] In the existing treatment technology, the chemical precipitation method can react perchlorate with metal atoms or ions to generate insoluble precipitates by adding appropriate chemical reagents (such as sodium chloride, barium hydroxide, calcium hydroxide, magnesium hydroxide, sodium sulfate, ammonium sulfate, calcium sulfate, copper sulfate, zinc sulfate, iron sulfate, etc.). Although the use of these precipitants can effectively improve water quality, reduce harmful substances in water, protect water environment, and improve water quality, the removal rate is not high, and it cannot meet the requirement of standard discharge. In addition, the precipitation process is easily affected by other ions. Ion exchange method has the advantages of simple operation, large adsorption capacity, short contact time and small occupied area, and is especially effective for removing low-concentration perchlorate. However, this method has the problem of difficult desorption, which limits its large-scale application, and cannot achieve harmless treatment of perchlorate from the root. The principle of microbial treatment method is that under anaerobic conditions and enzyme catalysis, perchlorate ions accept electrons from inorganic electron donors such as zero-valent iron and hydrogen to be reduced to chloride ions, achieving the purpose of biodegradation. The microbial treatment method is low in cost, but it takes a long time to take effect, and the microorganisms need to be enriched and cultured, which still has certain limitations. Membrane separation technology can separate perchlorate and water through the selective permeability of the membrane, and will not produce by-products. However, the membrane separation technology has high equipment cost, and the enriched perchlorate in the concentrated water needs further treatment, so it is restricted in practical application. The main disadvantage of activated carbon adsorption method is that the adsorption capacity of untreated activated carbon for perchlorate is limited, and the surface modification treatment must be carried out to improve the adsorption capacity for perchlorate. The adsorption effect of activated carbon for low-concentration perchlorate is not good, and the activated carbon adsorbed with perchlorate also faces the problem of treatment of enriched perchlorate. At present, the chemical reduction method uses Ti 3+ , Ru 2+ , Mo(III), Re-Pd, etc. as reducing agents to degrade perchlorate, but the degradation efficiency is not ideal, the reaction speed is slow, and the treatment time is long.

[0005] In addition, the wastewater produced by fireworks production and burning contains high content of perchlorate ions, and also contains sulfate ions, nitrate ions, chloride ions, potassium ions, sodium ions, lithium ions, strontium ions, copper ions, barium ions and other impurities, which interfere with the removal of perchlorate ions and affect the efficient removal of perchlorate ions.

[0006] Therefore, in the existing technology, different methods for removing perchlorate ions have their own limitations, and it is difficult to achieve high efficiency, high removal rate, high selectivity, and to solve the problem of perchlorate ions from the root. Whether it is sludge produced by chemical precipitation or concentrated liquid produced by ion exchange, further treatment is required, which increases the overall treatment cost. In addition, these methods have not effectively converted and utilized the potential resource of perchlorate, resulting in resource waste. SUMMARY

[0007] In view of the problems in the prior art in treating perchlorate in wastewater, the application provides a method for treating wastewater containing perchlorate, which adds mixed quaternary ammonium salt to the wastewater, and the mixed quaternary ammonium salt and the perchlorate in the industrial wastewater react to generate quaternary ammonium perchlorate precipitate, so that the quaternary ammonium perchlorate in the wastewater can be removed by filtration, the perchlorate in the industrial wastewater is purified, the enrichment of the perchlorate is realized, and the perchlorate in the industrial wastewater can be reduced to below 0.02 mg / L. The mixed quaternary ammonium salt is used in the application, the selectivity of the mixed quaternary ammonium salt to the perchlorate ion in the wastewater is high, the anti-interference ability is strong, the removal rate is high, and the efficient removal of the perchlorate ion in the wastewater is realized. According to the process provided in the application, the perchlorate in the wastewater is directly recovered in the form of quaternary ammonium perchlorate precipitate, and the recovered quaternary ammonium perchlorate precipitate can be used as an oxidizing agent for producing fireworks, so that the quaternary ammonium perchlorate is reused, and the recycling and utilization with high added value are realized.

[0008] According to the first technical scheme of the application, a method for treating wastewater containing perchlorate is provided.

[0009] A method for treating wastewater containing perchlorate, which comprises the following steps:

[0010] S1, adding quaternary ammonium salt to the wastewater containing perchlorate to be treated, and stirring to react;

[0011] S2, after the reaction is completed, standing, solid-liquid separation, and obtaining quaternary ammonium perchlorate and filtrate;

[0012] The quaternary ammonium salt is a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride in a molar ratio of 1:0.3-0.7.

[0013] Preferably, the quaternary ammonium salt is a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride in a molar ratio of 1:0.4-0.6.

[0014] In the application, after the quaternary ammonium salt is added in step S1, the molar concentration of the quaternary ammonium salt to the perchlorate ion in the wastewater is 1.0-1.2:1.

[0015] Preferably, after the quaternary ammonium salt is added in step S1, the molar concentration of the quaternary ammonium salt to the perchlorate ion in the wastewater is 1.0-1.1:1.

[0016] As preferred, step S1 is specifically adjusting the pH of the high-chlorate-containing wastewater to be treated to 5.0-7.5, detecting the concentration of perchlorate ions in the wastewater, mixing and dissolving octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride to obtain a mixture solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, adding the mixture solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride to the wastewater in proportion, stirring to react, generating flocculent precipitate, and completing the reaction until no new precipitate is formed or the concentration of perchlorate ions in the wastewater meets the discharge requirements.

[0017] As preferred, step S2 is specifically after the reaction is completed, standing for 1-12 h, precipitating crystalline solid, filtering to obtain filter residue and filtrate, and the filter residue being the quaternary ammonium perchlorate.

[0018] As preferred, the method further comprises step S3, drying the quaternary ammonium perchlorate obtained in step S2 to obtain white crystalline quaternary ammonium perchlorate.

[0019] As preferred, the high-chlorate-containing wastewater is wastewater generated in the production process of fireworks, and the concentration of perchlorate ions in the wastewater is 300-2000 mg / L, the concentration of sulfate ions is 50-300 mg / L, the concentration of nitrate ions is 30-300 mg / L, the concentration of chloride ions is 20-300 mg / L, the concentration of potassium ions is 70-700 mg / L, the concentration of sodium ions is 50-200 mg / L, the concentration of lithium ions is 10-100 mg / L, the concentration of strontium ions is 20-180 mg / L, the concentration of copper ions is 10-200 mg / L, and the concentration of barium ions is 10-150 mg / L.

[0020] According to the second embodiment of the present application, a utilization method of quaternary ammonium perchlorate is provided.

[0021] The white crystalline quaternary ammonium perchlorate obtained in the first embodiment is used as an oxidizing agent.

[0022] As preferred, the white crystalline quaternary ammonium perchlorate is used as an oxidizing agent for producing fireworks products.

[0023] In the prior art, the treatment of high-chlorate-containing wastewater faces the problems of strong chemical stability, high solubility, and difficulty in degradation. The conventional methods including chemical precipitation, ion exchange, and microbial treatment have low removal efficiency, complex operation, weak resistance to other ion interference, or secondary pollution risk. For example, the chemical precipitation method relies on the generation of insoluble precipitate by metal salt, but it is difficult to completely remove perchlorate, and the anti-interference ability is weak; the ion exchange resin is easy to saturate and difficult to regenerate; the microbial degradation requires specific culture conditions and has a long cycle. None of these methods can achieve the dual goals of high selectivity removal and resource utilization.

[0024] To solve the above problems, researchers found that the combination ability of perchlorate and specific cations is significantly different. By analyzing the molecular structure characteristics of quaternary ammonium salt, it is found that quaternary ammonium salt with specific carbon chain length and substituent can form stable complex. Experiments found that single quaternary ammonium salt has the problems of incomplete precipitation, weak anti-interference ability and easy dissolution, while the combination of two different structures of quaternary ammonium salt can produce synergistic effect. After repeated test verification, it is finally determined that the combination of benzene ring structure and long chain alkyl can break through the limitations of traditional quaternary ammonium salt precipitator.

[0025] Therefore, the present application proposes a method for treating wastewater containing perchlorate, comprising the following steps: adding a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride to the wastewater, stirring and then separating the precipitate from the filtrate.

[0026] Among them, octadecyl dimethyl benzyl ammonium chloride refers to a quaternary ammonium salt cation compound with benzene ring structure, and the benzene ring structure enhances the intermolecular binding force through π-π interaction. Octadecyl dimethyl benzyl ammonium chloride refers to a quaternary ammonium salt containing an octadecan long chain with a benzene ring structure, which promotes the formation of dense crystals of precipitate. Among them, the mixture refers to the combination of two quaternary ammonium salts in a specific ratio, which can be specifically used in a molar ratio of 1:0.3-0.7 to realize the balance of charge distribution optimization and molecular steric hindrance.

[0027] Specifically, the benzene ring and long chain alkyl of the two quaternary ammonium salts act on different sites of perchlorate. The benzene ring structure fixes the perchlorate ion through electron cloud interaction, and the long chain alkyl forms a three-dimensional network structure through hydrophobic association. During stirring, the cation and perchlorate ion undergo charge neutralization, and after the formation of crystal nucleus, it continues to grow into stable crystals through intermolecular force. During the standing stage, phase separation is realized by the self-weight of the crystals, and finally high-purity quaternary ammonium perchlorate crystals which can be resourcefully utilized are obtained.

[0028] Compared with the prior art, the traditional chemical precipitation method relies on the simple combination of metal ions and perchlorate, while the present scheme realizes molecular-level combination through directional assembly of organic cations. There is no implementation scheme in the prior art that uses double quaternary ammonium salt to form stable crystals through synergistic effect, especially the combination of benzene ring structure and long chain alkyl breaks through the steric hindrance limitation of single quaternary ammonium salt.

[0029] Through the above technical scheme, the present application realizes the directional capture and crystallization separation of perchlorate ions, and the concentration of perchlorate in the treated wastewater reaches the discharge standard, while obtaining high-purity crystalline product which can be directly used as oxidizing agent, solving the double problems of low removal rate and difficult utilization of by-products in traditional methods.

[0030] The hydrophobic force of octadecyl dimethyl benzyl ammonium chloride combined with perchlorate is moderate, which can form a stable complex structure, avoiding precipitation dissolution caused by too short chain length or steric hindrance caused by too long chain length. The long carbon chain structure of octadecyl trimethyl ammonium chloride promotes the further aggregation of the complex by stronger van der Waals force, forming a precipitate that is easy to separate. The charge neutralization ability and space matching characteristics of the two quaternary ammonium salts synergize to optimize the lattice arrangement of the precipitate, thereby improving the removal efficiency of perchlorate ions (including anti-interference effect, binding efficiency and separation efficiency).

[0031] The present application avoids precipitation dissolution and reduces the influence of steric hindrance on adsorption by combining different structures of quaternary ammonium salts, and synergistically enhances the stability of the precipitate through hydrophobic interaction and van der Waals force.

[0032] Through the above technical solutions, the present application solves the problems of insufficient removal rate, weak anti-interference ability and harsh reaction conditions of the existing chemical precipitation method, realizes the efficient and selective precipitation of perchlorate ions, and significantly improves the removal efficiency of perchlorate in wastewater.

[0033] The present application further proposes that the quaternary ammonium salt used is a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride in a molar ratio of 1:0.3-0.7 as a treatment agent.

[0034] The molar ratio of 1:0.3-0.7 refers to the dosage ratio range of the two quaternary ammonium salts, which can be realized by weighing equipment. This ratio range can balance the reaction activity and the stability of the precipitate.

[0035] Specifically, octadecyl dimethyl benzyl ammonium chloride quickly combines with perchlorate ions to form an initial precipitate, while the long carbon chain of octadecyl trimethyl ammonium chloride promotes the aggregation of precipitate particles through hydrophobic interaction. The two quaternary ammonium salts form a synergistic effect between molecules at a specific molar ratio, promoting the formation of a dense crystal of quaternary ammonium perchlorate. When the molar ratio is less than 0.3, the lack of long-chain fatty quaternary ammonium salt leads to loose precipitation; when the molar ratio is greater than 0.7, the excess long-chain fatty quaternary ammonium salt will wrap the reaction sites and hinder ion combination.

[0036] Compared with the prior art, the traditional chemical precipitation method uses a single quaternary ammonium salt or a mixture with an unoptimized ratio, which has the defect that the precipitation rate and structural stability cannot be balanced. For example, when octadecyl dimethyl benzyl ammonium chloride is used alone, the precipitate is easy to redissolve, and when octadecyl trimethyl ammonium chloride is used alone, the reaction rate is too low, affecting the selectivity of quaternary ammonium salt to perchlorate ions. The present application precisely controls the synergistic ratio of the two quaternary ammonium salts to achieve dynamic balance at the molecular level, maintaining high-speed ion combination, improving selectivity, and ensuring the mechanical strength of the precipitate.

[0037] By the technical scheme, the problem of low precipitation efficiency caused by improper proportioning of quaternary ammonium salt is solved, the formed quaternary ammonium perchlorate crystal has a regular shape and a compact packing structure, the residual ion concentration in the filtrate is effectively reduced in the solid-liquid separation process, the water content of the precipitate is reduced, and the subsequent resource utilization can be directly carried out.

[0038] The application further provides a technical scheme in which the molar concentration ratio of quaternary ammonium salt to perchlorate ions in the wastewater is controlled to be 1.0-1.2:1 (preferably 1.0-1.1:1) in step S1.

[0039] The molar concentration ratio refers to the ratio of the total amount of substance of quaternary ammonium salt cations to the amount of substance of perchlorate ions in the wastewater, which can be achieved by detecting the concentration of perchlorate ions in the wastewater and calculating the required dosage of quaternary ammonium salt. This parameter control can ensure that the stoichiometric relationship of reactants is optimally matched.

[0040] Specifically, in the wastewater treatment process, the actual concentration of perchlorate ions is first determined, and the theoretical dosage of mixed quaternary ammonium salt is calculated based on the detection value. The dosage is controlled in the range of 1.0-1.2 based on the benchmark ratio of 1.0, while considering the detection errors and reaction kinetics factors that may exist in actual industrial operation. The lower limit of the ratio ensures the theoretical requirement for complete conversion of reactants, and the upper limit ensures that the actual reaction proceeds sufficiently while avoiding excessive reagent residues that cause subsequent treatment burden. Through this precise control method, the combination reaction of quaternary ammonium salt cations and perchlorate ions is always in the best stoichiometric state.

[0041] Through the above technical scheme, the application effectively solves the problem of low precipitation efficiency caused by inaccurate proportioning of reactants in the chemical precipitation method for treating perchlorate wastewater, while ensuring the removal rate of perchlorate ions, significantly reducing the residual amount of unreacted quaternary ammonium salt, and achieving the dual optimization of economy and environmental protection in the wastewater treatment process.

[0042] The application further provides a technical scheme in which the pH of the wastewater containing perchlorate salt to be treated is adjusted to 5.0-7.5, the concentration of perchlorate ions in the wastewater is detected, octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride are mixed and dissolved (for example, they can be dissolved in tap water or distilled water, or dissolved in an appropriate amount of wastewater), to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride; the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is added to the wastewater in proportion, stirred and reacted to produce flocculent precipitate, and the reaction is completed when no new precipitate is formed or the concentration of perchlorate ions in the wastewater meets the discharge requirements.

[0043] The pH adjustment refers to controlling the acid-base degree of the wastewater in a weakly acidic or neutral range, and specifically, 0.1-0.5M sodium hydroxide or 0.05-0.25M hydrochloric acid solution can be used for adjustment, which can avoid the decomposition of quaternary ammonium salt or the dissolution of precipitate. The mixed dissolution refers to dissolving two quaternary ammonium salts in water or an organic solvent (preferably water) in advance to form a homogeneous solution, and specifically, mechanical stirring or ultrasonic dispersion can be used to achieve this, which can enhance the dispersibility and reactivity of the quaternary ammonium salt. The flocculent precipitate refers to a complex formed by the electrostatic interaction between the quaternary ammonium salt cation and the perchlorate anion, and the generation rate of the precipitate can be adjusted by controlling the stirring speed and reaction time, which indicates that the pollutants are being effectively fixed. The reaction endpoint judgment refers to observing the generation state of the precipitate by visual observation or detecting the concentration of the pollutants by an instrument, and specifically, ion chromatography or spectrophotometry can be used for real-time monitoring, which can ensure that the treatment process meets the preset standard.

[0044] Specifically, after the pH of the wastewater is adjusted to 5.0-7.5, the binding ability of the quaternary ammonium salt cation and the perchlorate is optimized, avoiding the decrease of the complexation reaction efficiency caused by the strong acid and strong base environment. After the two quaternary ammonium salts are mixed and dissolved into a homogeneous solution, their synergistic effect can cover perchlorates of different molecular sizes, increasing the amount of precipitate generated. During stirring, the reactants are in full contact to form a dense flocculent precipitate, and the reaction is stopped when the precipitate generation is terminated or the concentration of the pollutants meets the standard, thereby realizing dynamic control of the treatment process.

[0045] Through the above technical solutions, the present application realizes efficient removal of perchlorate ions, and the reaction conditions are clear and controllable, and the treatment endpoint can be quickly determined by the generation state of the precipitate or instrument detection. After wastewater treatment, the discharge standard can be directly reached, and waste of reagents and the risk of secondary pollution are avoided.

[0046] The present application further proposes that after the reaction is completed in step S2, the crystalline solid is precipitated after standing for 1-12 hours, and the filter residue and filtrate are obtained by filtration, and the filter residue is quaternary ammonium perchlorate.

[0047] The standing time refers to the time range during which the reaction system remains in a stationary state after stopping stirring, and can be achieved by natural sedimentation or assisted cooling. The time range can balance the crystallization efficiency and the processing period, avoiding insufficient crystal growth due to too short time or equipment utilization rate reduction due to too long time. The crystalline solid refers to a compound with a regular lattice structure formed by the combination of quaternary ammonium salt and perchlorate ions. The product can be precipitated from the solution in the form of a crystal by controlling the reaction conditions, which is different from amorphous flocculent precipitate. The regular shape is beneficial to improve the efficiency of subsequent solid-liquid separation. The filtration operation refers to the separation of solid and liquid phases by using a filter device, filter press, vacuum filtration device or centrifugal separation device. The step can effectively trap the crystalline solid and reduce liquid entrainment.

[0048] Specifically, after completing the complexation reaction of quaternary ammonium salt and perchlorate ions, the precipitate generated by the reaction is allowed to complete the crystal nucleus growth and crystal development process by controlling the standing time in the range of 1-12 hours. In this process, the quaternary ammonium salt cation and the perchlorate anion form a stable ion pair compound through electrostatic interaction, and the crystallization behavior is jointly regulated by the solution supersaturation, temperature and ionic strength. The formed crystalline solid has a certain crystal face orientation and a large particle size, and is not easy to penetrate the filter material and has a high bulk density during filtration, which significantly reduces the moisture content of the filter cake. After the solid and liquid phases are completely separated by physical separation means, the filter residue of quaternary ammonium perchlorate obtained can be directly used as an industrial raw material for subsequent processing.

[0049] Compared with the prior art, the flocculent precipitate produced by the traditional chemical precipitation method has a small particle size and a slow settling speed, and needs to add a coagulant and is easy to block the filter material during filtration. The present scheme forms a crystalline solid to make the precipitate have a regular shape and high mechanical strength, so that rapid settling and efficient filtration can be achieved without adding an auxiliary agent. The by-products in the prior art are usually mixed precipitates with complex components, which are difficult to realize resource utilization. The present scheme selects a specific mixed quaternary ammonium salt to make the product form a single component crystal, which creates conditions for the purification and reuse of by-products.

[0050] Through the above technical scheme, the present application effectively solves the problem of difficult solid-liquid separation caused by insufficient crystal growth during the precipitation of quaternary ammonium perchlorate. By optimizing the crystallization conditions, the precipitate forms a regular crystal structure, which significantly improves the filtration efficiency and product recovery rate. At the same time, the chemical composition of the crystalline product is clear, which can be directly used as an industrial oxidant raw material, realizing the dual goals of pollutant removal and resource recovery.

[0051] By the technical scheme, the application solves the problem of incomplete purification caused by residual trace quaternary ammonium perchlorate in filtrate, so that the concentration of organic salt in the final effluent reaches the surface water environmental quality standard, and the risk of secondary pollution caused by fluctuation of the efficiency of the precipitation process is avoided.

[0052] The application further provides that the quaternary ammonium perchlorate obtained after the reaction is dried to obtain white crystalline quaternary ammonium perchlorate.

[0053] Specifically, after the quaternary ammonium perchlorate in a wet state is subjected to dehydration treatment, the crystal structure tends to be complete, and the water adsorbed on the surface is effectively removed. The formation of the crystalline form makes the substance have definite chemical composition and physical properties, thereby meeting the application requirements as an oxidizing agent. The solid product after drying treatment can be directly packaged and stored, avoiding the problem of deliquescence or microbial growth that may occur in a wet state, thereby providing a basic condition for subsequent resource utilization.

[0054] By the technical scheme, the application effectively solves the problem of disposal of solid by-products in the wastewater treatment process, avoids the pollution caused by the accumulation of hazardous waste, and the high-purity crystalline material generated can be directly used as an oxidizing agent in the fireworks manufacturing field, thereby achieving the dual goals of pollution control and resource recycling.

[0055] The application further provides that the white crystalline quaternary ammonium perchlorate is used as an oxidizing agent.

[0056] The white crystalline quaternary ammonium perchlorate refers to a solid product generated by the reaction of quaternary ammonium salt and perchlorate ion, and specifically, a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride can be used to realize the precipitation reaction with perchlorate in wastewater. The product has the strong oxidation characteristics of perchlorate and the organic structure of quaternary ammonium salt. The oxidizing agent refers to a substance that can provide oxygen elements or promote oxidation reactions, and specifically, the release of active oxygen from the perchlorate ion in the quaternary ammonium perchlorate under high temperature or specific reaction conditions can be used to realize this, and the quaternary ammonium cation in the molecular structure can enhance the stability of the oxidation system.

[0057] Specifically, in the wastewater treatment process, quaternary ammonium salt and perchlorate ion form quaternary ammonium perchlorate solid through chemical precipitation reaction, and the solid forms white crystals after drying. When the crystalline material is directly used as an oxidizing agent, the perchlorate decomposes to produce oxygen under heating or catalytic conditions, thereby providing an oxygen source for combustion or oxidation reactions. For example, in the manufacture of fireworks, quaternary ammonium perchlorate not only participates in the combustion reaction as an oxidizing agent, but also improves the combustion stability of the fireworks formula through the quaternary ammonium salt component, thereby realizing the resource utilization of by-products.

[0058] In some embodiments, the white crystalline quaternary ammonium perchlorate is used in the production of fireworks products, which, after being mixed with metal powder and combustible material, forms a pyrotechnic composition; in another embodiment, the crystalline substance is used as an industrial oxidizing agent in organic synthesis reactions, replacing traditional potassium perchlorate or ammonium perchlorate.

[0059] Through the above technical solution, the present application realizes the direct resource utilization of wastewater treatment by-products, reduces the disposal steps of quaternary ammonium perchlorate solid waste, and provides a low-cost oxidizing agent source for industrial applications, solving the problem of double burden of pollutant disposal and resource consumption in traditional technology.

[0060] The present application further proposes the use of white crystalline quaternary ammonium perchlorate as an oxidizing agent for the production of fireworks products.

[0061] Among them, the oxidizing agent for the production of fireworks products refers to the application of solid products as energetic materials to pyrotechnic formulations, which can be realized by adjusting the formulation ratio, and this application mode takes advantage of the oxidation characteristics of quaternary ammonium perchlorate.

[0062] Through the above technical solution, the present application realizes the resource utilization of wastewater treatment by-products, effectively blocks the diffusion path of perchlorate in the environment, and provides a sustainable source of oxidizing agent for the fireworks manufacturing industry, establishing a material circulation channel between pollution control and industrial application.

[0063] Compared with the prior art, the technical solution provided by the present application has the following beneficial technical effects:

[0064] 1. The method for treating wastewater containing perchlorate and the recycling of quaternary ammonium perchlorate provided by the present application can form stable precipitates through the synergistic effect of specific quaternary ammonium salt mixtures, effectively remove perchlorate, and realize resource utilization of the product, which has the advantages of high treatment efficiency, good resource utilization, simple operation, and no secondary pollution.

[0065] 2. The present application is simpler to operate and more environmentally friendly. The perchlorate in industrial wastewater is reduced to below 0.02 mg / L, the dissolved oxygen of the wastewater is improved, the wastewater is prevented from becoming smelly during recycling, the COD content of the wastewater is reduced, and the treated effluent can be used as workshop cleaning water.

[0066] 3. The selective mixed quaternary ammonium salt of perchlorate in the present application can specifically adsorb and remove perchlorate in water under complex water quality conditions, and its selectivity for perchlorate is much higher than that for nitrate, chloride, and high-valence sulfate and phosphate, reducing the interference of other coexisting ions in the water body. DETAILED DESCRIPTION

[0067] The technical solutions of the present application are illustrated below, and the scope of protection of the present application includes but is not limited to the following embodiments.

[0068] The sources of substances used in the embodiments of the present application are as follows:

[0069] Perchlorate-containing wastewater: wastewater in the reaction sedimentation tank of a flower and firecracker enterprise, perchlorate concentration 583.2 mg / L.

[0070] The contents of the main component substances in the wastewater are as shown in the following table:

[0071]

[0072] Benzalkonium chloride (mixture): Tianjin Kewei Zhonghong Environmental Protection Technology Co., Ltd., 85409-22-9, average molecular weight 404. Ingredient content: C8-benzalkonium chloride (benzyl dimethyl octyl ammonium chloride): 0.8%, C10-benzalkonium chloride (N-coco-N,N-dimethyl benzyl ammonium chloride): 8.0%, C12-benzalkonium chloride (dodecyl dimethyl benzyl ammonium chloride): 53.0%, C14-benzalkonium chloride (tetradecyl dimethyl benzyl ammonium chloride): 30.0%, C16-benzalkonium chloride (hexadecyl dimethyl benzyl ammonium chloride): 7.0%, C18-benzalkonium chloride (octadecyl dimethyl benzyl ammonium chloride): 1.2%.

[0073] Benzyl dimethyl octyl ammonium chloride: CAS No. 959-55-7, Shanghai Yuanye Biological Technology Co., Ltd., molecular weight: 283.88

[0074] N-coco-N,N-dimethyl benzyl ammonium chloride: CAS: 965-32-2, Sigma-Aldrich (Shanghai) Trading Co., Ltd., molecular weight: 311.93.

[0075] Dodecyl dimethyl benzyl ammonium chloride: CAS No. 139-07-1, Shanghai McLean Biochemical Science and Technology Co., Ltd., molecular weight: 339.99.

[0076] Tetradecyl dimethyl benzyl ammonium chloride: CAS No. 139-08-2, Shanghai McLean Biochemical Science and Technology Co., Ltd., molecular weight: 368.04.

[0077] Hexadecyl dimethyl benzyl ammonium chloride: CAS No. 122-18-9, Hunan Yunbang Biological Technology Co., Ltd., molecular weight: 396.09.

[0078] Octadecyl dimethyl benzyl ammonium chloride: CAS No. 122-19-0, Shanghai McLean Biochemical Science and Technology Co., Ltd., molecular weight: 424.15.

[0079] Octadecyltrimethylammonium chloride: CAS No. 112-03-8, Shanghai Aladdin Biochem Technology Co., Ltd., molecular weight 348.05.

[0080] Dodecyltrimethylammonium chloride: CAS No. 112-00-5, Shandong Anmi Chemical Technology Co., Ltd., molecular weight 263.89.

[0081] Tetradecyltrimethylammonium chloride: CAS No. 4574-04-3, Shanghai Kanglang Biological Technology Co., Ltd., molecular weight 291.94.

[0082] Standard for detecting the concentration of perchlorate ions in wastewater or filtrate: Discharge Standard of Industrial Wastewater Perchlorate Pollutants (DB43 / 3001-2024).

[0083] Example 1

[0084] A method for treating wastewater containing perchlorate, the method comprising the following steps:

[0085] S1, 1 t of wastewater containing perchlorate is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.69 kg (3.99 mol) of octadecyldimethylbenzylammonium chloride and 0.69 kg (1.99 mol) of octadecyltrimethylammonium chloride are mixed and dissolved with the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride, and the mixed solution of octadecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is carried out until no new precipitate is formed, and the reaction is completed.

[0086] S2, stop stirring, and stand for 4 hours, precipitate crystalline solid, filter with a filter bag filter, drain water through filter cloth, and obtain wet filter residue and filtrate;

[0087] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate.

[0088] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0089] Example 2

[0090] A method for treating wastewater containing perchlorate, the method comprising the following steps:

[0091] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.95 kg (4.6 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.48 kg (1.38 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0092] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0093] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0094] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0095] Example 3

[0096] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0097] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.95 kg (4.6 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.48 kg (1.38 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0098] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0099] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0100] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0101] Example 4

[0102] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0103] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.59 kg (3.74 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.78 kg (2.24 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0104] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and the water is drained through the filter cloth to obtain wet filter residue and filtrate;

[0105] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0106] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0107] Example 5

[0108] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0109] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.59 kg (3.74 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.78 kg (2.24 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0110] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and the water is drained through the filter cloth to obtain wet filter residue and filtrate;

[0111] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0112] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0113] Comparative Example 1

[0114] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0115] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 2.54 kg (5.98 mol) of octadecyl dimethyl benzyl ammonium chloride is dissolved to obtain an octadecyl dimethyl benzyl ammonium chloride solution, and the octadecyl dimethyl benzyl ammonium chloride solution is gradually added to the wastewater; stirring is started, and the reaction is carried out until no new precipitate is formed, and the reaction is completed;

[0116] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with a filter bag filter, drain water through filter cloth, obtain wet filter residue and filtrate;

[0117] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0118] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0119] Comparative Example 2

[0120] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0121] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 2.08 kg (5.98 mol) of octadecyl trimethyl ammonium chloride is dissolved in the wastewater in the reaction precipitation tank to obtain an octadecyl trimethyl ammonium chloride solution, and the octadecyl trimethyl ammonium chloride solution is gradually added to the wastewater; stirring is started, and the reaction is carried out until no new precipitate is formed, and the reaction is completed;

[0122] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with a filter bag filter, drain water through filter cloth, obtain wet filter residue and filtrate;

[0123] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0124] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0125] Comparative Example 3

[0126] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0127] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.61 kg (3.99 mol) of benzalkonium chloride and 0.69 kg (1.99 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of benzalkonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of benzalkonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0128] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0129] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0130] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0131] Comparative Example 4

[0132] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0133] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.61 kg (3.99 mol) of benzalkonium chloride and 0.69 kg (1.99 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of benzalkonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of benzalkonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0134] S2, stop stirring, and stand for 4 hours, and crystalline solids are precipitated, which are filtered with a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0135] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0136] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0137] Comparative Example 5

[0138] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0139] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.24 kg (3.99 mol) of N-cetyl-N,N-dimethyl benzyl ammonium chloride and 0.69 kg (1.99 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of N-cetyl-N,N-dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of N-cetyl-N,N-dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0140] S2, stop stirring, and stand for 4 hours, and crystalline solid is precipitated, which is filtered by a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0141] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0142] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0143] Comparative Example 6

[0144] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0145] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.24 kg (3.99 mol) of N-cetyl-N,N-dimethyl benzyl ammonium chloride and 0.69 kg (1.99 mol) of octadecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of N-cetyl-N,N-dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of N-cetyl-N,N-dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0146] S2, stop stirring, and stand for 4 hours, and crystalline solid is precipitated, which is filtered by a filter bag filter, and water is drained through filter cloth to obtain wet filter residue and filtrate;

[0147] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0148] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0149] Comparative Example 7

[0150] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0151] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.47 kg (3.99 mol) of tetradecyldimethylbenzylammonium chloride and 0.69 kg (1.99 mol) of octadecyltrimethylammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of tetradecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride, and the mixed solution of tetradecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0152] S2, stop stirring, and stand for 4 hours, and then the crystalline solid is separated out and filtered with a filter bag filter, and the water is drained through the filter cloth to obtain wet filter residue and filtrate;

[0153] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8 h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0154] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0155] Comparative Example 8

[0156] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0157] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.47 kg (3.99 mol) of tetradecyldimethylbenzylammonium chloride and 0.69 kg (1.99 mol) of octadecyltrimethylammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of tetradecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride, and the mixed solution of tetradecyldimethylbenzylammonium chloride and octadecyltrimethylammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is continued until no new precipitate is formed, and the reaction is completed;

[0158] S2, stop stirring, and stand for 4 hours, and then the crystalline solid is separated out and filtered with a filter bag filter, and the water is drained through the filter cloth to obtain wet filter residue and filtrate;

[0159] S3, the wet filter residue is dried in a blast drying oven at 60°C for 8 h to obtain white waxy solid quaternary ammonium perchlorate salt.

[0160] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0161] Comparative Example 9

[0162] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0163] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.69 kg (3.99 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.53 kg (1.99 mol) of dodecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and dodecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and dodecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is carried out until no new precipitate is formed, and the reaction is completed;

[0164] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with a filter bag filter, drain through filter cloth, obtain wet filter residue and filtrate;

[0165] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0166] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0167] Comparative Example 10

[0168] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0169] S1, 1 t of wastewater containing perchlorate salt is pumped into a reaction precipitation tank, and the pH of the wastewater is adjusted to 7.0; 1.69 kg (3.99 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.53 kg (1.99 mol) of dodecyl trimethyl ammonium chloride are mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and dodecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and dodecyl trimethyl ammonium chloride is gradually added to the wastewater; stirring is started, and the reaction is carried out until no new precipitate is formed, and the reaction is completed;

[0170] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with a filter bag filter, drain through filter cloth, obtain wet filter residue and filtrate;

[0171] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0172] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0173] Comparative Example 11

[0174] A method for treating wastewater containing perchlorate salt, comprising the following steps:

[0175] S1, 1 t of wastewater containing perchlorate salt was pumped into a reaction precipitation tank, and the pH of the wastewater was adjusted to 7.0; 2.11 kg (4.98 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.35 kg (1.00 mol) of octadecyl trimethyl ammonium chloride were mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride was gradually added to the wastewater; stirring was started, and the reaction was continued until no new precipitate was formed, and the reaction was completed;

[0176] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with filter bag filter, drain through filter cloth, obtain wet filter residue and filtrate;

[0177] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0178] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0179] Comparative Example 12

[0180] A method for treating wastewater containing perchlorate salt, the method comprising the following steps:

[0181] S1, 1 t of wastewater containing perchlorate salt was pumped into a reaction precipitation tank, and the pH of the wastewater was adjusted to 7.0; 2.11 kg (4.98 mol) of octadecyl dimethyl benzyl ammonium chloride and 0.35 kg (1.00 mol) of octadecyl trimethyl ammonium chloride were mixed and dissolved in the wastewater in the reaction precipitation tank to obtain a mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride, and the mixed solution of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride was gradually added to the wastewater; stirring was started, and the reaction was continued until no new precipitate was formed, and the reaction was completed;

[0182] S2, stop stirring, stand for 4 hours, precipitate crystalline solid, filter with filter bag filter, drain through filter cloth, obtain wet filter residue and filtrate;

[0183] S3, dry the wet filter residue in a blast drying oven at 60°C for 8h, obtain white waxy solid quaternary ammonium perchlorate salt.

[0184] The concentration of perchlorate ions in the filtrate obtained in step S2 is detected.

[0185] The concentration of perchlorate ions in the filtrate obtained in Examples 1-5 and Comparative Examples 1-12 is detected, and the results are as follows:

[0186]

[0187] The above merely provides an example of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for treating wastewater containing perchlorate, characterized in that: The method includes the following steps: S1. Add quaternary ammonium salt to the perchlorate-containing wastewater to be treated and stir to carry out the reaction; S2. After the reaction is complete, let it stand, separate the solid and liquid, and obtain quaternary ammonium perchlorate and filtrate. The quaternary ammonium salt is a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride in a molar ratio of 1:0.3-0.

7.

2. The method for treating perchlorate-containing wastewater according to claim 1, characterized in that: The quaternary ammonium salt is a mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride in a molar ratio of 1:0.4-0.

6.

3. The method for treating perchlorate-containing wastewater according to claim 1, characterized in that: After the addition of quaternary ammonium salt in step S1, the molar concentration of quaternary ammonium salt to perchlorate ions in the wastewater is 1.0-1.2:

1.

4. The method for treating perchlorate-containing wastewater according to claim 1, characterized in that: After the addition of quaternary ammonium salt in step S1, the molar concentration of quaternary ammonium salt to perchlorate ions in wastewater is 1.0-1.1:

1.

5. The method for treating perchlorate-containing wastewater according to any one of claims 1-4, characterized in that: Step S1 specifically involves: adjusting the pH of the perchlorate-containing wastewater to be treated to 5.0-7.5, and detecting the concentration of perchlorate ions in the wastewater; mixing and dissolving octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride; adding the mixture of octadecyl dimethyl benzyl ammonium chloride and octadecyl trimethyl ammonium chloride to the wastewater in a certain proportion, stirring to carry out the reaction, producing flocculent precipitate, and reacting until no new precipitate is formed or the concentration of perchlorate ions in the wastewater meets the discharge requirements, at which point the reaction is complete.

6. The method for treating perchlorate-containing wastewater according to any one of claims 1-4, characterized in that: Step S2 is as follows: After the reaction is completed, let it stand for 1-12 hours to precipitate a crystalline solid. Filter the solid to obtain a filter residue and a filtrate. The filter residue is a quaternary ammonium perchlorate salt.

7. The method for treating perchlorate-containing wastewater according to any one of claims 1-4, characterized in that: The perchlorate-containing wastewater is wastewater generated during the fireworks production process. The wastewater contains perchlorate ions at concentrations of 300-2000 mg / L, sulfate ions at concentrations of 50-300 mg / L, nitrate ions at concentrations of 30-300 mg / L, chloride ions at concentrations of 20-300 mg / L, potassium ions at concentrations of 70-700 mg / L, sodium ions at concentrations of 50-200 mg / L, lithium ions at concentrations of 10-100 mg / L, strontium ions at concentrations of 20-180 mg / L, copper ions at concentrations of 10-200 mg / L, and barium ions at concentrations of 10-150 mg / L.

8. The method for treating perchlorate-containing wastewater according to claim 6, characterized in that: The method also includes step S3, drying the perchlorate quaternary ammonium salt obtained in step S2 to obtain white crystalline perchlorate quaternary ammonium salt.

9. The method for treating perchlorate-containing wastewater according to claim 8, characterized in that: The white crystalline perchloric acid quaternary ammonium salt was used as an oxidizing agent.

10. The method for treating perchlorate-containing wastewater according to claim 9, characterized in that: The white crystalline perchloric acid quaternary ammonium salt is used as an oxidant in the production of fireworks products.

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