A homogeneous emulsion type fluorine removing agent, a preparation method and application thereof

Abstract

The application relates to a preparation method of a defluorination agent prepared from eggshells and defatted bone powder, comprising the following steps: step one: waste animal bone pretreatment: removing meat and fat on the animal bone, drying and crushing to obtain powder F1, ready for use; step two: eggshell pretreatment: drying and crushing the eggshell to obtain powder F2, ready for use; step three: preparation of modified mixed powder: uniformly mixing the powder F1 and the powder F2 in a ratio of 1:(2.5-3), high-temperature calcining, adding a solvent to the high-temperature calcined solid mixture for hydrothermal treatment, filtering the hydrothermal treated product, washing, drying to obtain the modified mixed powder; and step four: preparation of a homogeneous emulsion type defluorination agent: dissolving the modified mixed powder in water to obtain the homogeneous emulsion type defluorination agent. The homogeneous emulsion defluorination agent prepared in the application does not add any organic matter, and has excellent defluorination effect and stability.

Description

Technical Field

[0001] This invention belongs to the field of water treatment material preparation technology, specifically relating to a method for preparing a defluorinating agent using eggshells and defatted bone meal, and its application. Background Technology

[0002] With the development of modern industry, the production and use of fluorides are increasing in various industries. Currently, wastewater from industries such as metal smelting, semiconductor manufacturing, fluoride ore mining, coal chemical industry, and electroplating contains large amounts of fluoride and fluorides. This fluoride-containing wastewater not only corrodes equipment but also causes serious environmental pollution and endangers human health.

[0003] Currently, the main methods for treating fluoride-containing industrial wastewater both domestically and internationally include chemical precipitation, coagulation sedimentation, adsorption, electrocoagulation, ion exchange resin, reverse osmosis, liquid membrane, and electrodialysis. Most of these technologies are mature and have been applied in engineering projects. However, for low-concentration fluoride-containing wastewater, coagulation sedimentation and adsorption are the most widely used methods.

[0004] The adsorption method mainly utilizes adsorbent materials with high specific surface area and easy regeneration. Through physical and chemical reactions, the fluoride dissolved in the water undergoes adsorption or exchange with other ions or groups in the adsorbent, thereby adsorbing the fluoride onto the adsorbent and achieving the effect of fluoride removal. The coagulation and sedimentation method mainly utilizes coagulants such as iron and aluminum salts to hydrolyze in water. The hydrolysis products have ion exchange and colloidal adsorption with fluoride ions, thereby achieving the effect of fluoride removal.

[0005] In existing deep defluorination technologies, the adsorption method uses adsorbents with drawbacks such as low adsorption capacity and complex process operation and management. Developing highly efficient chlorine-free defluorination agents is of great significance. However, chlorine-free defluorination agents typically contain added organic polymers. The addition of organic polymers reduces the stability of the defluorination agent, causing it to become ineffective after a certain period. Furthermore, the addition of organic polymers increases the cost of the defluorination agent, making chlorine-free defluorination agents generally more expensive.

[0006] Therefore, it is necessary to develop a low-cost, efficient, and stable chlorine-free defluorinating agent. Summary of the Invention

[0007] The primary objective of this invention is to provide a method for preparing a homogeneous emulsion-like defluorinating agent.

[0008] The second objective of this invention is to provide a homogeneous emulsion-like defluorinating agent.

[0009] A third objective of this invention is to provide an application of a homogeneous emulsion-like defluorinating agent.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A method for preparing a homogeneous emulsion-like defluorinating agent includes the following steps:

[0012] Step 1: Pre-treatment of waste animal bones: Remove meat and fat from animal bones, dry them, and then pulverize them to obtain powder F1 for later use;

[0013] Step 2: Eggshell pretreatment: Dry the eggshells and then crush them to obtain powder F2 for later use;

[0014] Step 3: Preparation of modified mixed powder: Powder F1 and powder F2 are mixed evenly at a ratio of 1:(2.5~3) and then calcined at high temperature. The solid mixture after high temperature calcination is added to a solvent for hydrothermal treatment. The product after hydrothermal treatment is filtered, washed, and dried to obtain modified mixed powder.

[0015] Step 4: Preparation of homogeneous emulsion defluorinating agent: Dissolve the modified mixed powder in water to obtain a homogeneous emulsion defluorinating agent.

[0016] When the inventor used solid defluorinating agents to defluorinate wastewater, he found that the solid defluorinating agents did not disperse well in the wastewater and had poor defluorination effect. Meanwhile, the liquid defluorinating agents on the market all contain organic matter, which has poor stability and is not environmentally friendly. Therefore, the inventor thought of developing a homogeneous emulsion defluorinating agent with excellent stability that does not contain any added organic matter.

[0017] The inventors creatively utilized a combination of high-temperature calcination and hydrothermal treatment to modify eggshell powder and bone meal in a 1:(2.5-3) ratio. The bulk density of the modified mixed powder was 0.7-0.8 g / cm³. 3 The modified mixed powder dissolves in a solvent to obtain a uniform and stable homogeneous emulsion defluorinating agent, which improves the defluorination effect while ensuring the stability of the defluorinating agent.

[0018] The modified mixed powder appears as dispersed suspended fine particles in water with a porous structure, which is used to adsorb fluoride ions in wastewater. The added modified mixed powder also plays a role in fluoride fixation. For low-concentration fluoride-containing wastewater, the concentration of CaF2 precipitate formed by the added calcium salt and fluoride ions is low. After adding the modified mixed powder, it will play a solidification role, increasing the local concentration of CaF2. When used in combination with calcium salt, it is more conducive to the removal of fluoride ions.

[0019] Further, the pulverized powders F1 and F2 are sieved, and powders F1 and F2 with a mesh size of 100-200 are selected for step three.

[0020] Preferably, step four further includes the addition of one or more of aluminum salts, iron salts, and magnesium salts, as well as a pH adjuster; the pH adjuster is used to adjust the pH of the homogeneous emulsion defluorinating agent to 3-4.

[0021] In aluminum salts, some aluminum exists as polyhydroxycations [Al13 O4(OH) 24 ] 7+ It exists in a form with high charge density and moderate degree of polymerization. Because the ionic radii and charges of F- and OH- are very similar,

[0022] [Al 13 O4(OH) 24 ] 7+ Some of the OH- ions can undergo ion exchange with F- ions to obtain Al. 13 F n (OH) m Precipitation. Therefore, aluminum salts can achieve deep defluorination through strong adsorption and ion exchange.

[0023] Magnesium / iron salts form colloidal particles in water, possessing a large specific surface area, carrying a positive charge, and exhibiting a high zeta potential. In contrast, fluoride ions have a small radius and strong electronegativity. The flocs strongly adsorb fluoride ions, causing a decrease in the zeta potential, resulting in floc instability and sedimentation.

[0024] The uniformly dispersed mixture of modified eggshell powder and defatted bone meal in the homogeneous emulsion defluorinator facilitates charge adsorption and enables rapid flocculation.

[0025] Preferably, by weight, aluminum salt: 40-55 parts, magnesium salt: 10-20 parts, iron salt: 20-30 parts, modified mixed powder: 10-15 parts, and water: 20-30 parts.

[0026] Furthermore, the animal bones mentioned in step one are one or more of the following: pig bones, cow bones, fish bones, sheep bones, dog bones, and chicken bones.

[0027] Furthermore, the eggshell mentioned in step two is one or more of the following: chicken eggshell, duck eggshell, goose eggshell, and quail eggshell.

[0028] Furthermore, the pH adjuster is one or more of citric acid, sodium citrate, acetic acid, and sodium acetate.

[0029] Furthermore, the high-temperature calcination is performed at a high temperature of 450–550°C for 4–6 hours.

[0030] Furthermore, the hydrothermal reaction conditions are 200℃~300℃ for 1h~3h.

[0031] The present invention also provides a homogeneous emulsion-like defluorinating agent, which is prepared by the above preparation method.

[0032] The present invention also provides the application of a homogeneous emulsion-like defluorinating agent prepared by the above preparation method.

[0033] The present invention has the following advantages and effects compared with the prior art:

[0034] 1. This application innovatively uses eggshell powder and defatted bone powder as raw materials, and modifies the mixture of eggshell powder and defatted bone powder using a high-temperature calcination + hydrothermal method. The modified eggshell powder and defatted bone powder mixture has porous adsorption properties, and the modified eggshell powder and defatted bone powder mixture is uniformly dispersed in the solvent, forming a homogeneous emulsion. When mixed evenly with the wastewater to be defluorinated, the reaction rate is faster and the defluorination effect is excellent.

[0035] 2. Homogeneous emulsion defluorinating agents can be directly pumped into the treatment system, facilitating automatic control of the dosage, reducing manual operation and dust problems, and are suitable for large-scale continuous treatment systems;

[0036] 3. This defluorinating agent formula is entirely composed of inorganic substances and does not contain any organic polymers (most chlorine-containing defluorinating agents add organic substances to improve the defluorination effect). Defluorinating agents with added organic substances have poor stability and are prone to decomposition after being left for a period of time, resulting in a decrease in defluorination effect. The homogeneous emulsion defluorinating agent prepared in this application has better stability than liquid-phase defluorinating agents with added organic substances on the market, and makes full use of waste eggshells and waste animal bones, realizing waste utilization. This formula is lower in cost and more environmentally friendly than chlorine-free defluorinating agents on the market.

[0037] 4. This formula, due to the addition of eggshell powder and defatted bone meal, can not only treat low-fluoride wastewater, but also has a certain effect on low-temperature and low-turbidity wastewater. Detailed Implementation

[0038] The preparation method of the photothermal hydrogel of the present invention will be further described below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0039] Example 1

[0040] Step 1: Pre-treatment of waste pig bones: Remove the meat and fat from the pig bones, dry them, crush and sieve them to obtain 100-200 mesh powder F1, for later use;

[0041] Step 2: Pre-treatment of eggshells: Dry the eggshells, crush them, and sieve them to obtain 100-200 mesh powder F2, which is ready for use.

[0042] Step 3: Preparation of modified mixed powder: Powder F1 and powder F2 are mixed evenly in a 1:3 ratio and then calcined at high temperature. After calcination at 450℃ for 5 hours, the solid mixture is added to deionized water and subjected to hydrothermal treatment at 250℃ for 2 hours. The product after hydrothermal treatment is filtered, washed, and dried to obtain a mixture of modified eggshell powder and defatted bone powder. The bulk density of the modified mixed powder is 0.72 g / cm³. 3 。;

[0043] Step 4: Preparation of homogeneous emulsion defluorinating agent A1: Dissolve 10 parts by weight of 100-200 mesh modified mixed powder in 20 parts of pure water to obtain a homogeneous emulsion defluorinating agent.

[0044] Example 2

[0045] Step 1: Pre-treatment of waste pig bones: Remove the meat and fat from the pig bones, dry them, crush and sieve them to obtain 100-200 mesh powder F1, for later use;

[0046] Step 2: Pre-treatment of eggshells: Dry the eggshells, crush them, and sieve them to obtain 100-200 mesh powder F2, which is ready for use.

[0047] Step 3: Preparation of modified mixed powder: Powder F1 and powder F2 are mixed evenly in a ratio of 1:2.8 and then calcined at high temperature. After calcination at 500℃ for 5 hours, the solid mixture is added to deionized water and subjected to hydrothermal treatment at 250℃ for 2 hours. The product after hydrothermal treatment is filtered, washed, and dried to obtain a mixture of modified eggshell powder and defatted bone powder. The bulk density of the modified mixed powder is 0.74 g / cm³. 3 。;

[0048] Step 4: Preparation of homogeneous emulsion defluorinating agent A2: Dissolve 40 parts aluminum sulfate, 20 parts ferric sulfate, 10 parts magnesium sulfate, and 5 parts citric acid in 20 parts pure water by weight, and then add 10 parts of 100-200 mesh modified mixed powder to obtain a homogeneous emulsion defluorinating agent with pH 3.

[0049] Example 3

[0050] Step 1: Pre-treatment of waste pig bones: Remove the meat and fat from the pig bones, dry them, crush and sieve them to obtain 100-200 mesh powder F1, for later use;

[0051] Step 2: Pre-treatment of eggshells: Dry the eggshells, crush them, and sieve them to obtain 100-200 mesh powder F2, which is ready for use.

[0052] Step 3: Preparation of modified mixed powder: Powder F1 and powder F2 are mixed evenly in a ratio of 1:2.5 and then calcined at high temperature. After calcination at 500℃ for 5 hours, the solid mixture is added to deionized water and subjected to hydrothermal treatment at 250℃ for 2 hours. The product after hydrothermal treatment is filtered, washed, and dried to obtain a mixture of modified eggshell powder and defatted bone powder. The bulk density of the modified mixed powder is 0.80 g / cm³. 3 。;

[0053] Step 4: Preparation of homogeneous emulsion defluorinating agent A3: Dissolve 55 parts aluminum sulfate, 25 parts ferric sulfate, 15 parts magnesium sulfate, and 8 parts citric acid in 25 parts pure water by weight, and then add 12 parts of a mixture of 100-200 mesh modified eggshell powder and defatted bone powder to obtain a homogeneous emulsion defluorinating agent with a pH of 4.

[0054] Comparative Example 1

[0055] Step 1: Pre-treatment of waste pig bones: Remove the meat and fat from the pig bones, dry them, crush and sieve them to obtain 100-200 mesh powder F1, for later use;

[0056] Step 2: Preparation of modified defatted bone meal: Powder F1 was calcined at 500℃ for 5 hours. The resulting solid mixture was then added to deionized water and hydrothermally treated at 250℃ for 2 hours. The hydrothermally treated product was filtered, washed, and dried to obtain modified defatted bone meal with a bulk density of 0.93 g / cm³. 3 ;

[0057] Step 3: Preparation of homogeneous emulsion defluorinating agent D1: Dissolve 40 parts aluminum sulfate, 20 parts ferric sulfate, 10 parts magnesium sulfate, and 5 parts citric acid in 20 parts pure water by weight, and then add 10 parts 100-200 mesh modified defatted bone powder to obtain an emulsion defluorinating agent with a pH of 3.

[0058] Comparative Example 2

[0059] Step 1: Pre-treatment of eggshells: Dry the eggshells, crush them, and sieve them to obtain 100-200 mesh powder F2, which is ready for use.

[0060] Step 2: Preparation of modified eggshell powder: Powder A was calcined at high temperature (500℃ for 5 hours). The resulting solid mixture was then added to deionized water and hydrothermally treated at 250℃ for 2 hours. The hydrothermally treated product was filtered, washed, and dried to obtain modified eggshell powder with a bulk density of 0.41 g / cm³. 3 ;

[0061] Step 3: Preparation of homogeneous emulsion defluorinating agent D2: Dissolve 40 parts aluminum sulfate, 20 parts ferric sulfate, 10 parts magnesium sulfate, and 5 parts citric acid in 20 parts pure water by weight, and then add 10 parts 100-200 mesh modified eggshell powder to obtain an emulsion defluorinating agent with a pH of 3.

[0062] Test case

[0063] Defluoridator effectiveness test

[0064] The defluorination effects of the self-made homogeneous emulsion defluorinating agents A1-A3 in Examples 1-3, the self-made liquid phase defluorinating agents D1-D2 in Comparative Examples 1-2, the purchased defluorinating agent B (containing organic polymer, liquid, Shandong Huanrui Ecological Technology Co., Ltd., model: GMS-F6), and the purchased defluorinating agent C (solid, Anhui Rundao Ecological Environment Engineering Technology Co., Ltd., model: RD-DeF-1) were tested respectively.

[0065] Take 250g each of the first-grade fluoride-containing wastewater (fluoride content approximately 10ppm) from Yibin Yingfa Deyao Technology Co., Ltd., and dispense them into beakers. Add 2.5g of self-made homogeneous emulsion defluorinating agent A1 (diluted 10 times) to beaker 1, 2.5g of self-made emulsion defluorinating agent A2 (diluted 10 times) to beaker 2, 2.5g of self-made emulsion defluorinating agent A3 (diluted 10 times) to beaker 3, 2.5g of self-made emulsion defluorinating agent D1 (diluted 10 times) to beaker 4, 2.5g of self-made emulsion defluorinating agent D2 (diluted 10 times) to beaker 5, 2.5g of defluorinating agent B (diluted 10 times) to beaker 6, and 2.5g of defluorinating agent C to beaker 7.

[0066] Set the program for the experimental mixer and conduct a flocculation and settling test. After the first stage of the flocculation and settling test is completed, use sodium bicarbonate to adjust the pH of the solution to around 7, turn on the coagulation experimental mixer, and conduct a second stage of flocculation and settling test. After the solution has been settling for a period of time, take the supernatant and determine the fluoride ion content F in the filtrate.

[0067] Table 1. Comparison of defluorination effects of defluorinating agents - experimental data

[0068]

[0069] Table 1 shows the experimental data comparing the effects of defluorinating agents. As can be seen from Table 1, the defluorination effect of the self-made defluorinating agents A1-A3 is close to that of the purchased defluorinating agent B containing organic polymers. The defluorination effect is better, the defluorination time is shorter, and the reaction rate is faster.

[0070] Compared to the self-made homogeneous emulsion defluorinating agents A1-A3 and the purchased defluorinating agent B, the purchased solid defluorinating agent C has a longer reaction time and a slower reaction rate, and its defluorination effect is somewhat worse than that of the homogeneous emulsion defluorinating agents A1-A3 and the purchased defluorinating agent B.

[0071] Comparative Examples 1 and 2 used only one of the modified eggshell powder and defatted bone powder dissolved in water to form liquid-phase defluorinating agents D1 and D2, respectively. The defluorination effect was inferior to that of Example 2, which used a modified mixed powder dissolved in water to form an emulsion-like defluorinating agent A2. This is because the bulk densities of the modified eggshell powder and modified defatted bone powder are different. The modified eggshell powder has a lower bulk density, making it prone to floating and resulting in poor dispersion in water, failing to form a homogeneous emulsion and affecting the defluorination effect and stability. The modified defatted bone powder has a higher bulk density, making it prone to sinking and resulting in poor dispersion in solvent, failing to form a homogeneous emulsion and affecting the defluorination effect and stability. Therefore, using only one of the modified eggshell powder and defatted bone powder dissolved in a solvent is insufficient to obtain a homogeneous emulsion. Modification by mixing the two substances in an appropriate ratio can obtain a modified mixed powder, which can then produce a stable homogeneous emulsion and achieve excellent defluorination results.

[0072] Stability comparison experiment of defluorinating agents

[0073] The stability of the self-prepared homogeneous emulsion defluorinating agents A1-A3 in Examples 1-3, the self-prepared liquid defluorinating agents D1 and D2 in Comparative Examples 1-2, and the purchased defluorinating agent B were tested respectively.

[0074] The homogeneous emulsion defluorinating agents A1-A3 prepared in Examples 1-3, the liquid defluorinating agents D1 and D2 prepared in Comparative Examples 1-2, and the purchased defluorinating agent B (containing organic polymers) were placed for 7 days, 15 days, and 30 days, respectively, and defluorination tests were conducted. After 7 days, 15 days, and 30 days, defluorination experiments were performed on fluoride-containing wastewater, and the fluoride ion content F in the filtrate was measured to compare the stability of the defluorinating agents. The test results are as follows:

[0075] Table 2. Comparison of stability data of defluorinating agents

[0076]

[0077]

[0078] As shown in Table 2, the defluorination effect of the self-prepared homogeneous emulsion defluorinating agents A1-A3 in Examples 1-3 did not change significantly after 30 days of storage; the defluorination effect of the purchased defluorinating agent B weakened after 7 days of storage and was poor after 30 days of storage.

[0079] Comparative Examples 1 and 2, which used only one of the modified eggshell powder and defatted bone powder dissolved in water to form a liquid-phase defluorinating agent, showed a slightly weakened defluorination effect after 7 days. Although their stability was better than that of the purchased defluorinating agent B, it was not as good as the emulsion-like defluorinating agent formed by dissolving the modified mixed powder in water used in Example 2.

[0080] The excellent stability of the self-prepared homogeneous emulsion defluorinating agents A1-A3 in Examples 1-3 is due to the physical and chemical reactions that accompany the modification process. By mixing eggshell powder and defatted bone powder and then modifying them, a more uniform and stable modified mixed powder can be obtained through physicochemical reactions. The modified mixed powder is dissolved in a solvent to obtain a homogeneous emulsion defluorinating agent with higher stability.

[0081] The effect of defluoridating agents on the treatment of low-temperature, low-turbidity wastewater

[0082] Take 250g of low-temperature, low-turbidity river water with a turbidity of 8.94 NTU; dispense it into beakers. Add 2.53g of the homogeneous emulsion defluorinating agent A2 (diluted 10 times) prepared in Example 2 to beaker 1, add 2.58g of defluorinating agent B (diluted 10 times) to beaker 2, and add 2.50g of defluorinating agent C to beaker 3. Set the experimental mixer program and conduct a flocculation test. After the flocculation test is completed, let it stand for 10 minutes, observe the settling effect of the flocs, and test the turbidity of the river water.

[0083] Table 3. Treatment effect of defluoridating agents on low-temperature, low-turbidity wastewater

[0084]

[0085]

[0086] As shown in Table 3, the self-made homogeneous emulsion defluorinating agent in Example 2 has a better flocculation effect on low-temperature and low-turbidity wastewater compared with solid defluorinating agent C and liquid defluorinating agent B, and can significantly reduce the turbidity of the wastewater.

[0087] In summary, the homogeneous emulsion defluorinating agent prepared in this application has excellent defluorination effect and stability.

Claims

1. A method for preparing a homogeneous emulsion-like defluorinating agent, characterized in that: Includes the following steps: Step 1: Pre-treatment of waste animal bones: Remove meat and fat from animal bones, dry them, and then pulverize them to obtain powder F1 for later use; Step 2: Eggshell pretreatment: Dry the eggshells and then crush them to obtain powder F2 for later use; Step 3: Preparation of modified mixed powder: Mix powder F1 and powder F2 in a ratio of 1:(2.5~3). After thorough mixing, the mixture is calcined at high temperature. The resulting solid mixture is then subjected to hydrothermal treatment with a solvent. The hydrothermally treated product is filtered, washed, and dried to obtain a modified mixed powder. The high-temperature calcination is performed at 450–550 °C for 4–6 h; the hydrothermal reaction is conducted at 200–300 °C for 1–3 h; and the bulk density of the modified mixed powder is 0.7–0.8 g / cm³. 3 ; Step 4: Preparation of homogeneous emulsion defluorinating agent: Dissolve the modified mixed powder in water to obtain a homogeneous emulsion defluorinating agent. Step 4 also involves adding one or more of aluminum salts, iron salts, and magnesium salts, as well as a pH adjuster. The pH adjuster is used to adjust the pH of the homogeneous emulsion defluorinating agent to between 3 and 4.

2. The method for preparing a homogeneous emulsion-like defluorinating agent according to claim 1, characterized in that: Sift the powder F1 after step one and the powder F2 after step two, and select powder F1 and powder F2 with a mesh size of 100~200 for step three.

3. The method for preparing a homogeneous emulsion-like defluorinating agent according to claim 2, characterized in that: By weight, aluminum salt: 40-55 parts, magnesium salt: 10-20 parts, iron salt: 20-30 parts, modified mixed powder: 10-15 parts, water: 20-30 parts.

4. A method for preparing a homogeneous emulsion-like defluorinating agent according to any one of claims 1 to 3, characterized in that: The animal bones mentioned in step one are at least one of the following: pig bones, cow bones, fish bones, sheep bones, dog bones, and chicken bones.

5. A method for preparing a homogeneous emulsion-like defluorinating agent according to any one of claims 1 to 3, characterized in that: The eggshell mentioned in step two is at least one of chicken eggshells, duck eggshells, goose eggshells, and quail eggshells.

6. A homogeneous emulsion defluorinating agent prepared by the preparation method of a homogeneous emulsion defluorinating agent according to any one of claims 1 to 5.

7. The application of the homogeneous emulsion defluorinator prepared by the preparation method of the homogeneous emulsion defluorinator according to any one of claims 1 to 5.

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