Defluorination agent for deep treatment and preparation method thereof

Abstract

The invention discloses an advanced treatment defluorination agent and a preparation method thereof, and the advanced treatment defluorination agent comprises the following components by mass: 5-8 parts of aluminum sulfate; 1-3 parts of polymeric ferric sulfate; 0.5-1 part of polyaluminum chloride; 1 to 3 parts of tetramethylammonium hydroxide; 1-3 parts of magnesium chloride; 0.1 part of hydrochloric acid; 0.1 part of a polyacrylamide cation; the deep treatment defluorination agent and the preparation method thereof have the advantages that the preparation is simple, the use is convenient, the operation cost is low, the concentration of fluorine ions in water can be quickly reduced through the adsorption precipitation effect, and meanwhile, the sludge yield is low, the adsorption is tight, and the sludge is not easy to float to the surface of a water body.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a deep treatment fluorine removal agent and a preparation method thereof. BACKGROUND

[0002] With the rise of fluorine chemical industry, fluorine-containing wastewater is inevitably produced in many industrial production processes. Once discharged into water bodies, fluorine-containing wastewater will affect plant photosynthesis and nutrient absorption, thereby causing the growth rate of plants to slow down, and even stop growing or die. High concentrations of fluorides can also cause damage to animal organs and tissues, interfere with their normal physiological metabolic activities, and cause abnormal behavior, growth retardation or death of animals. Long-term consumption of these organisms can cause chronic poisoning in the human body, causing damage to the nervous, digestive, cardiovascular and other systems. The "Integrated Wastewater Discharge Standard" (GB8978-1996) stipulates that the content of fluoride ions in industrial wastewater should be less than 10 mg / L, and some provinces have more stringent regulations on fluoride ions, stipulating that the content of fluoride ions in industrial wastewater should be less than 1.5 mg / L.

[0003] Fluorine-containing wastewater mainly contains hydrogen fluoride, fluorosilicic acid and other fluorides, as well as inorganic salts and organic matter, etc. This complexity greatly increases the difficulty of treating fluorine-containing wastewater. In engineering practice, the treatment technologies mainly used include precipitation method, adsorption method, membrane separation method, etc. In addition, in order to improve the defluorination effect, people often combine the above several processes to form a composite defluorination technology. The chemical precipitation method is mature and has good effect, but the amount of solid waste produced is large, and attention should be paid to the scale inhibition of the precipitating agent; the coagulation and sedimentation method has low cost, and the ratio and use of the reagent need to be selected and optimized; the adsorption method is suitable for treating low-concentration wastewater and is widely used and efficient; the membrane separation method is suitable for low-concentration and efficient defluorination, but also has the disadvantage of high treatment cost. At present, Zhang Dandan et al. have studied a high-efficiency defluorination material and its preparation method, and the obtained high-efficiency defluorination material has strong adsorption capacity and high adsorption capacity for fluoride ions, and can be recycled multiple times, which has great value for the treatment of fluorine-containing wastewater. (Zhang Dandan et al. A high-efficiency defluorination material and its preparation method [P]. China: CN119236905A, 2025.01.03) Shi Zhengfeng et al. have explored a high-efficiency defluorination agent suitable for photovoltaic wastewater and its preparation process, which optimizes the action time and effect of the agent, and avoids the problem of unstable efficiency caused by too fast release of traditional defluorination agents. (Shi Zhengfeng et al. A high-efficiency defluorination agent suitable for photovoltaic wastewater and its preparation process [P]. China: CN119390220A, 2025.02.07) Chen Zhaoliang et al. have studied a recyclable defluorination agent and its preparation method, and the prepared defluorination agent has excellent adsorption capacity, significantly improving the removal efficiency of fluoride ions in wastewater, and can also remove heavy metal ions in wastewater [P]. China: CN118929816A, 2024.11.12).

[0004] The prior art mainly has the following disadvantages:

[0005] I. The existing fluoride removal agent is mainly calcium salt, which mainly uses calcium fluoride precipitation. The solubility of calcium fluoride precipitation is high, and it is difficult to reduce the fluoride concentration to below 1.5 mg / L after treatment.

[0006] II. The calcium fluoride precipitation is easy to wrap lime, resulting in an increase in the dosage, a high pH of the effluent, and the need to add reagents to adjust the pH again before drainage.

[0007] III. Some use expensive adsorbents, and the backwash water needs to be treated additionally, which has high operation cost and needs to be replaced regularly.

[0008] IV. Some composite reagents may contain irritating chemical components, which need to be strictly protected during storage and use. If not handled properly, it may cause secondary pollution and needs to be used in combination with other technologies, which increases the operation complexity. SUMMARY

[0009] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title. Such simplifications or omissions cannot be used to limit the scope of the present application.

[0010] 1. Technical problems to be solved:

[0011] In order to solve the problems of the prior art, such as the difficulty in reducing the fluoride concentration to below 1.5 mg / L after treatment, the easy wrapping of lime by calcium fluoride precipitation, high operation cost, and the risk of secondary pollution, the present application is proposed.

[0012] Therefore, the purpose of the present application is to provide a deep treatment fluoride removal agent and a preparation method thereof, which is simple to prepare, convenient to use, and has low operation cost. It can quickly reduce the concentration of fluoride ions in water through adsorption and precipitation, and has less sludge production, tight adsorption, and is not easy to float to the surface of the water body.

[0013] 2. Technical solutions:

[0014] In order to solve the above technical problems, according to one aspect of the present application, the present application provides the following technical solutions:

[0015] A deep treatment fluoride removal agent, comprising the following components in parts by mass:

[0016] Aluminum sulfate: 5-8 parts;

[0017] Polyferric sulfate: 1-3 parts;

[0018] Polyaluminum chloride 0.5-1 part;

[0019] Tetramethylammonium hydroxide: 1-3 parts;

[0020] Magnesium chloride: 1-3 parts;

[0021] Hydrochloric acid: 0.1 parts;

[0022] Polyacrylamide cation: 0.1 parts;

[0023] Polyacrylamide anion: 0.1 parts.

[0024] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0025] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0026] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0027] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0028] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0029] As a preferred embodiment of the preparation method of the deep treatment fluorine removal agent of the application, the steps include the following: under normal temperature, the to-be-dissolved substances are respectively placed in water according to the required mass fraction, and continuously stirred until completely dissolved.

[0030] 3. Beneficial effects:

[0031] Compared with the prior art, the application has the beneficial effects that:

[0032] The deep treatment fluorine removal agent and the preparation method thereof can further reduce the fluorine ions in the fluorine-containing wastewater to less than 1.5 mg / L, meeting the current water discharge requirements.

[0033] The deep treatment fluorine removal agent and the preparation method thereof have the advantages of less dosage, low cost, no change of pH in water, and no need to adjust the pH in water.

[0034] The deep treatment fluorine removal agent and the preparation method thereof have the advantages of simple configuration, and the composite raw materials can be directly configured on site or uniformly configured in a factory and then transported to the site for use. DETAILED DESCRIPTION

[0035] To make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application are described in detail below.

[0036] The orientation or position relationship indicated in the terms is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0037] The connection mode in the terms should be understood broadly, for example, "connection" can be fixed connection, detachable connection, or integral connection; can be mechanical connection, electrical connection; can be direct connection, indirect connection through an intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] The embodiments of the present application are further described in detail below.

[0039] The present application provides a deep treatment fluorine removal agent and a preparation method thereof.

[0040] The deep treatment fluorine removal agent of the present embodiment comprises the following steps:

[0041] The components include the following components by mass fraction:

[0042] Aluminum sulfate: 5-8 parts;

[0043] Polyferric sulfate: 1-3 parts;

[0044] Polyaluminum chloride: 0.5-1 part;

[0045] Tetramethylammonium hydroxide: 1-3 parts;

[0046] Magnesium chloride: 1-3 parts;

[0047] Hydrochloric acid: 0.1 part;

[0048] Polyacrylamide cation: 0.1 part;

[0049] Polyacrylamide anion: 0.1 part.

[0050] It is worth mentioning that, including the following steps, normal temperature state, respectively, the to be dissolved material according to the required mass fraction of each into the water, stirring until dissolved completely.

[0051] Then, according to the required mass fraction of the dissolved solution is mixed and stirred to obtain a mixed solution, adding a certain mass fraction of the agent, fully stirring and uniformity can be prepared depth fluoride removal compound agent.

[0052] At the same time, according to the actual concentration of fluoride wastewater, the appropriate content of the above defluorination agent is added, and the stirring speed is 600-800 r / min.

[0053] Further, the addition of polyacrylamide cation slow stirring 15-20 minutes, stirring speed 100-200 r / min, and standing for 3-5 minutes to complete the defluorination precipitation reaction.

[0054] Then, continue to add polyacrylamide anion to meet the effluent discharge requirements.

[0055] Further, the to be dissolved material is aluminum sulfate, polymeric ferric sulfate, polyaluminum chloride, magnesium chloride and polyacrylamide.

[0056] Example 1:

[0057] According to the mass fraction, aluminum sulfate 5 parts, polyaluminum chloride 5 parts, polyacrylamide cation 0.1 part.

[0058] Example 2:

[0059] According to the mass fraction, aluminum sulfate 9 parts, polyaluminum chloride 1 part, polyacrylamide cation 0.1 part.

[0060] Example 4:

[0061] According to the mass fraction, aluminum sulfate 8 parts, polymeric ferric sulfate 1 part, polyaluminum chloride 1 part, polyacrylamide cation 0.1 part.

[0062] Example 5:

[0063] According to the mass fraction, aluminum sulfate 7 parts, polymeric ferric sulfate 1 part, magnesium chloride 1 part, polyaluminum chloride 0.5 part, tetramethylammonium hydroxide 1 part, hydrochloric acid 0.1 part, polyacrylamide cation 0.1 part, polyacrylamide anion 0.1 part:

[0064] The fluorine-containing wastewater of actual project is used as experimental water, and A solution and B solution are two photovoltaic fluorine-containing wastewaters which are preliminarily treated by calcium oxide chemical precipitation. The fluorine ion concentration of A solution after chemical precipitation is 3.8 mg / L, and the fluorine ion concentration of B solution after chemical precipitation is 5.2 mg / L. The composition of B solution is more complex, and the impurities of other ions are more. Due to the limitation of calcium fluoride solubility product, it is difficult to further reduce the concentration of fluorine ions in water by chemical precipitation alone. At the beginning of the experiment, 1 L of A solution and B solution is placed in a beaker, and the above examples are added according to the required mass fraction

[0065] The mass fraction of each is 10 g, which is dissolved in 100 ml of water. Aluminum sulfate, polymeric ferric sulfate, polyaluminum chloride, magnesium chloride, and polyacrylamide are respectively added to the water according to the required mass fraction, and stirred until completely dissolved. The dissolved solutions are mixed according to the required mass fraction to obtain a mixed solution. A certain mass fraction of tetramethylammonium hydroxide, hydrochloric acid, and other reagents are added, and the mixture is stirred uniformly to obtain a deep fluorine removal compound reagent. 1 ml of each compound reagent is taken from A solution, and the actual effective content is 0.1 g / L. 2 ml of each compound reagent is taken from B solution, and the actual effective content is 0.2 g / L. The mixture is stirred at a speed of 600-800 r / min for 15 minutes, and then polyacrylamide cation is added and stirred at a speed of 100-200 r / min for 15 minutes. The fluorine removal precipitation reaction is completed after standing for 5 minutes. The fluorine ion concentration and wet sludge weight of A and B solutions are then measured.

[0066] Table 1 shows the fluorine removal effect of the compound fluorine removal reagent.

[0067]

[0068] As can be seen from Table 1, the aluminum salt has good adsorption effect on fluorine ions in water, but the precipitation effect is poor, the sludge production is large, and the sludge is difficult to gather. By adding iron salt to water sample B, it can be seen that insoluble iron fluoride precipitate is formed, and the combination of iron salt and aluminum salt promotes the precipitation effect, but the sludge gathering effect is general. By adding functional cations and tetramethylammonium hydroxide to the compound reagent, the amino group enhances the adsorption capacity of fluorine ions, and the functional cations promote the formation of precipitate by complexation, so the precipitation effect is more obvious. However, the complex water quality characteristics of water sample B still make it difficult to gather the sludge. As can be seen from Example 5, the addition of polyacrylamide anion to the water can further gather the sludge tightly due to the adsorption of ionic bonds, which is convenient for subsequent sludge treatment. As can be seen, the proportioning formula of Example 4 can treat most of the secondary treatment of fluorine-containing wastewater, and the fluorine ion concentration can be reduced to below 1.5 mg / L. For complex ion-containing fluorine-containing wastewater, Example 5 can further improve the gathering degree of sludge, which is convenient for subsequent sludge treatment.

[0069] In summary, this invention effectively overcomes the drawbacks of traditional technologies and improves sedimentation efficiency through the synergistic effects of aluminum salts, iron salts, flocculants, amino groups, and functional cations. Aluminum salts hydrolyze in water to form positively charged colloids, which undergo complexation, ligand exchange, and physical adsorption with fluoride ions. The hydrolysis intermediates and the final aluminum hydroxide colloids capture fluoride ions through electrostatic adsorption, while aluminum and fluoride ions form aluminum fluoride precipitates, achieving fluoride removal. Iron salts hydrolyze to generate positively charged colloidal particles, which combine with fluoride ions to form insoluble iron fluoride precipitates. This process relies on the chemical complexation between iron and fluoride ions, while the iron salt hydrolysis products exhibit physical adsorption and sweeping sedimentation effects on fluoride ions. The combined use of aluminum and iron salts reduces pH dependence and broadens the applicable pH range. Amino groups form stable complexes with fluoride ions through coordination bonds; their mechanisms include electrostatic attraction, hydrogen bonding, and chemical chelation, thereby achieving selective capture of fluoride ions. Amino groups enhance the adsorption capacity of fluoride ions, while functional cations promote precipitation through complexation, reducing the solubility of calcium fluoride. The synergistic effect of amino groups and functional cations weakens the impact of anions such as sulfate and chloride on fluoride removal. The flocculant optimizes the sediment structure, improves sludge dewatering performance, and reduces sludge treatment costs. Operation is simple; the reagent can be added directly without complex pretreatment or subsequent neutralization, adapting to the treatment needs of wastewater with different concentrations of fluoride. Furthermore, the reagent ratio can be optimized and adjusted according to the actual water quality conditions on site to achieve the desired fluoride removal effect.

[0070] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A deep-treatment defluorination agent, characterized in that, By mass parts, it includes the following components: Aluminum sulfate: 5-8 parts; Polyferric sulfate: 1-3 parts; Polyaluminum chloride 0.5-1 part; Tetramethylammonium hydroxide: 1-3 parts; Magnesium chloride: 1-3 parts; Hydrochloric acid: 0.1 parts; Cationic polyacrylamide: 0.1 parts; Anionic polyacrylamide: 0.1 parts.

2. A method for preparing a deep-treatment defluorination agent as described in claim 1, characterized in that, The process includes the following steps: at room temperature, dissolve each of the substances to be dissolved in water according to the required mass fractions, stirring continuously until completely dissolved.

3. The method for preparing the deep-treatment defluorination agent according to claim 2, characterized in that, The dissolved solution is mixed and stirred according to the required mass proportions to obtain a mixed solution. A certain mass proportion of the reagent is added, and the mixture is stirred thoroughly to obtain a deep defluorination compound reagent.

4. The method for preparing the deep-treatment defluorination agent according to claim 3, characterized in that, Add an appropriate amount of the above-mentioned defluorinating agent according to the actual concentration of the fluoride-containing wastewater, and stir rapidly for 15 to 25 minutes at a stirring speed of 600 to 800 r / min.

5. The method for preparing the deep-treatment defluorination agent according to claim 4, characterized in that, Add cationic polyacrylamide and stir slowly for 15 to 20 minutes at a stirring speed of 100 to 200 r / min. Let it stand for 3 to 5 minutes to complete the defluorination precipitation reaction.

6. The method for preparing the deep-treatment defluorination agent according to claim 5, characterized in that, Continue adding anionic polyacrylamide to meet effluent discharge requirements.

7. The method for preparing the deep-treatment defluorination agent according to claim 6, characterized in that, The substances to be dissolved are aluminum sulfate, polyferric sulfate, polyaluminum chloride, magnesium chloride, and polyacrylamide.

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