Homogeneous emulsion fluorine removal agent as well as preparation method and application thereof

Abstract

The invention relates to a method for preparing a fluorine removal agent by using eggshells and degreased bone meal, which comprises the following steps: step 1, pretreatment of waste animal bones: removing meat and fat on the animal bones, drying and crushing to obtain powder F1 for later use; step 2, pre-treating eggshells: drying the eggshells and then crushing the eggshells to obtain powder F2 for later use; step 3, preparing modified mixed powder: uniformly mixing the powder F1 and the powder F2 according to a ratio of 1: (2.5-3), then carrying out high-temperature calcination, adding a solvent into a solid mixture subjected to high-temperature calcination, carrying out hydrothermal treatment, and filtering, washing and drying a product subjected to hydrothermal treatment to obtain the modified mixed powder; and 4, preparing the homogeneous emulsion fluorine removal agent: dissolving the modified mixed powder in water to obtain the homogeneous emulsion fluorine removal agent. The homogeneous emulsion fluorine removal agent prepared by the invention is not added with any organic matter, and has excellent fluorine removal effect and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment material preparation, and specifically relates to a defluoridating agent prepared by utilizing eggshell and defatted bone powder, a preparation method and application thereof. Background Art

[0002] With the development of modern industry, the production and use of fluoride in various industries are increasing. At present, the wastewater generated by metal smelting, semiconductor manufacturing, fluorine-containing ore mining, coal chemical industry, electroplating and other industries contains a large amount of fluorine and fluoride. These fluoride-containing wastewaters not only corrode equipment, but also cause serious pollution to the environment and endanger human health.

[0003] At present, the main treatment methods for fluorine-containing industrial wastewater at home and abroad include chemical precipitation, coagulation sedimentation, adsorption, electrocoagulation, ion exchange resin, reverse osmosis, liquid membrane, electrodialysis, etc. Most of the technologies are mature and have engineering applications. However, for low-concentration fluorine-containing wastewater, the most widely used methods are coagulation sedimentation and adsorption.

[0004] The adsorption method mainly utilizes adsorption materials with high specific surface area and easy regeneration. Through physical and chemical reactions, the fluorine dissolved in the water is adsorbed or exchanged with other ions or groups in the adsorbent, so that the fluorine is adsorbed on the adsorbent to achieve the effect of fluorine removal; the coagulation and precipitation method mainly utilizes coagulants such as iron salts and aluminum salts to hydrolyze in water. The hydrolysis products have ion exchange, colloidal adsorption and other effects with fluoride ions, thereby achieving the effect of fluorine removal.

[0005] In the existing deep defluorination technology, the adsorption materials used in the adsorption method have the disadvantages of low adsorption capacity, complex process operation and management. The development of efficient chlorine-free defluorination agents is of great significance. Chlorine-free defluorination agents generally contain organic polymers, which make the stability of the defluorination agent poor, making the defluorination agent ineffective after a certain period of time, and the addition of organic polymers will increase the cost of the defluorination agent, so the price of chlorine-free defluorination agents is generally higher.

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

[0007] The first object of the present invention is to provide a method for preparing a homogeneous emulsion defluorinating agent.

[0008] The second object of the present invention is to provide a homogeneous emulsion defluorinating agent.

[0009] The third object of the present invention is to provide an application of a homogeneous emulsion defluorinating agent.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

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

[0012] Step 1: Pretreatment of waste animal bones: remove the meat and fat from the animal bones, dry and crush them to obtain powder F1 for later use;

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

[0014] Step 3: preparing modified mixed powder: mixing powder F1 and powder F2 at a ratio of 1: (2.5-3) and calcining at high temperature, adding solvent to the solid mixture after high temperature calcination for hydrothermal treatment, filtering the product after hydrothermal treatment, washing, and drying to obtain modified mixed powder;

[0015] Step 4: Prepare a 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 were not well dispersed in the wastewater and had poor defluorination effects. Liquid defluorinating agents on the market all had organic matter added to them, and had poor stability and were not environmentally friendly. Therefore, the inventor thought of developing a liquid phase homogeneous emulsion defluorinating agent with excellent stability and no organic matter added.

[0017] The inventor creatively used high temperature calcination treatment + hydrothermal treatment to modify the eggshell powder and bone powder in a mixing ratio of 1: (2.5-3). The bulk density of the modified mixed powder was 0.7-0.8g / cm 3 The modified mixed powder is dissolved in a solvent to obtain a uniform and stable homogeneous emulsion defluorinating agent, which improves the defluorinating effect while ensuring the stability of the defluorinating agent.

[0018] The modified mixed powder appears as dispersed suspended fine particles in water and has a porous structure, which uses its porous structure to adsorb fluoride ions in wastewater; the added modified mixed powder also plays a role in fixing fluoride. For low-concentration fluoride-containing wastewater, the concentration of CaF2 precipitate generated 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. Using it in combination with calcium salt is more conducive to the removal of fluoride ions.

[0019] Furthermore, the crushed powders F1 and F2 are sieved, and the powders F1 and F2 with 100-200 meshes are selected to proceed to step three.

[0020] Preferably, in step 4, one or more of aluminum salt, iron salt, magnesium salt and a pH adjuster are further added; the pH adjuster is used to adjust the pH of the homogeneous emulsion defluorinating agent to 3-4.

[0021] Aluminum salts contain part of the aluminum in the form of polyhydric cations [Al13 O4(OH) 24 ] 7+ The morphology exists with high charge density and medium polymerization degree. Since the ionic radius and charge of F- and OH- are very close,

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

[0023] Magnesium salt / iron salt forms colloidal particles in water, which have a large specific surface area, carry positive charge, and have a high Zeta potential, while fluoride ions have a small radius and strong electronegativity. The flocs have a strong adsorption effect on fluoride ions, which reduces the Zeta potential, making the flocs unstable and precipitating.

[0024] The uniformly dispersed mixture of modified eggshell powder and defatted bone powder in the homogeneous emulsion-like defluoridator facilitates charge adsorption and can achieve 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, water: 20-30 parts.

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

[0027] Furthermore, the eggshell in step 2 is one or more of 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 calcination at a high temperature of 450 to 550° C. for 4 to 6 hours.

[0030] Furthermore, the hydrothermal reaction is carried out at 200°C to 300°C for 1h to 3h.

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

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

[0033] Compared with the prior art, the present invention has the following advantages and effects:

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

[0035] 2. Homogeneous emulsion defluoridation agent can be directly pumped into the treatment system, which is convenient for automatic control of dosage, reduces manual operation and dust problems, and is suitable for large-scale continuous treatment systems;

[0036] 3. The defluorinating agent formula is all inorganic, and no organic polymers are added (most chlorine-containing defluorinating agents will add organic matter to improve the defluorination effect). The defluorinating agent with added organic matter has poor stability. The defluorinating agent is prone to decomposition after being left for a period of time, and the defluorination effect becomes worse. The homogeneous emulsion defluorinating agent prepared in this application is more stable than the liquid phase defluorinating agent with added organic matter on the market, and it makes full use of discarded eggshells and discarded animal bones to achieve waste utilization. Compared with the chlorine-free defluorinating agent on the market, this formula has lower cost and is more environmentally friendly.

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

[0038] The preparation method of the photothermal effect hydrogel of the present invention is further described below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0039] Example 1

[0040] Step 1: Pretreatment of discarded 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: Pretreatment of egg shells: dry the egg shells, crush and sieve to obtain 100-200 mesh powder F2 for later use;

[0042] Step 3: Preparation of modified mixed powder: Powder F1 and powder F2 were mixed in a ratio of 1:3 and then calcined at high temperature. After calcination at 450°C for 5 hours, the solid mixture was added with deionized water and hydrothermally treated at 250°C for 2 hours. The product after hydrothermal treatment was filtered, washed, and dried to obtain a mixture of modified eggshell powder and defatted bone powder. The bulk density of the modified mixed powder was 0.72 g / cm 3 . ;

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

[0044] Example 2

[0045] Step 1: Pretreatment of discarded 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: Pretreatment of egg shells: dry the egg shells, crush and sieve to obtain 100-200 mesh powder F2 for later use;

[0047] Step 3: Prepare 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°C for 5 hours, deionized water is added to the solid mixture and hydrothermally treated at 250°C 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 / cm 3 . ;

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

[0049] Example 3

[0050] Step 1: Pretreatment of discarded 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: Pretreatment of egg shells: dry the egg shells, crush and sieve to obtain 100-200 mesh powder F2 for later use;

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

[0053] Step 4: Prepare a homogeneous emulsion defluorinator A3: Dissolve 55 parts of aluminum sulfate, 25 parts of iron sulfate, 15 parts of magnesium sulfate, and 8 parts of citric acid in 25 parts of 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 defluorinator with a pH of 4.

[0054] Comparative Example 1

[0055] Step 1: Pretreatment of discarded 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 powder: calcining powder F1 at high temperature, adding deionized water to the solid mixture after calcination at 500℃ for 5h and hydrothermally treating at 250℃ for 2h, filtering, washing and drying the product after hydrothermal treatment to obtain modified defatted bone powder, the bulk density of which is 0.93g / cm 3 ;

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

[0058] Comparative Example 2

[0059] Step 1: Pretreatment of egg shells: dry the egg shells, crush and sieve to obtain 100-200 mesh powder F2 for later use;

[0060] Step 2: Preparation of modified eggshell powder: Powder A was calcined at high temperature, and the solid mixture after calcination at 500°C for 5h was added with deionized water for hydrothermal treatment at 250°C for 2h. The product after hydrothermal treatment was filtered, washed, and dried to obtain modified eggshell powder. The bulk density of the modified eggshell powder was 0.41g / cm 3 ;

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

[0062] Test example

[0063] Fluoride removal effect test

[0064] The defluorination effects of the homemade homogeneous emulsion defluorinating agents A1-A3 of Examples 1-3, the homemade liquid defluorinating agents D1-D2 of Comparative Example 1-2, the purchased defluorinating agent B (containing organic polymers, 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 of each of the first-level fluorine-containing wastewater from Yibin Yingfa Deyao Technology Co., Ltd. (fluorine content is about 10ppm) and divide them into beakers. Add 2.5g of homemade homogeneous emulsion defluorinator A1 (diluted 10 times) to beaker 1, add 2.5g of homemade emulsion defluorinator A2 (diluted 10 times) to beaker 2, add 2.5g of homemade emulsion defluorinator A3 (diluted 10 times) to beaker 3, add 2.5g of homemade emulsion defluorinator D1 (diluted 10 times) to beaker 4, add 2.5g of homemade emulsion defluorinator D2 (diluted 10 times) to beaker 5, add 2.5g of defluorinator B (diluted 10 times) to beaker 6, and add 2.5g of defluorinator C to beaker 7.

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

[0067] Table 1 Defluorination effect comparison experimental data of defluorination agent

[0068]

[0069] Table 1 is the experimental data for comparing the effects of defluorination agents. It can be seen from Table 1 that the defluorination effects of the homemade defluorination agents A1-A3 are close to the defluorination effects of the purchased defluorination agent B containing organic polymers, with better defluorination effects, shorter defluorination time and faster reaction rate.

[0070] Compared with the homemade homogeneous emulsion defluorinators A1-A3 and the purchased defluorinator B, the purchased solid defluorinator C has a longer reaction time and a slower reaction rate. The defluorination effect of the defluorinator is worse than that of the homogeneous emulsion defluorinators A1-A3 and the purchased defluorinator B.

[0071] Comparative Examples 1 and 2 respectively use only one of the modified eggshell powder and defatted bone meal dissolved in water to form liquid phase defluoridation agents D1 and D2 for defluorination, and the defluorination effect is inferior to that of the emulsion defluoridation agent A2 formed by dissolving the modified mixed powder in water in Example 2. This is because the bulk density of the modified eggshell powder and the modified defatted bone meal is different. The bulk density of the modified eggshell powder is small, it is easy to float, and the dispersion effect in water is not good and cannot form a homogeneous emulsion, which affects the defluorination effect and stability; the bulk density of the modified defatted bone meal is large, it is easy to sink, and the dispersion effect in the solvent is not good and cannot form a homogeneous emulsion, which affects the defluorination effect and stability. Therefore, it is impossible to obtain a homogeneous emulsion by only using one of the modified eggshell powder and defatted bone meal dissolved in a solvent. The modified mixed powder can be obtained by mixing the two substances in an appropriate proportion for modification. The modified mixed powder can obtain a stable homogeneous emulsion and achieve an excellent defluorination effect.

[0072] Comparative experiment on stability of defluorination agent

[0073] The stabilities of the self-prepared homogeneous emulsion defluorinating agents A1-A3 of Examples 1-3, the self-prepared liquid defluorinating agents D1 and D2 of 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 polymer) were placed for 7 days, 15 days, and 30 days, respectively, and then defluorination tests were carried out. After the test was placed for 7 days, 15 days, and 30 days, the defluorination experiment was carried out on the fluoride-containing wastewater, and the fluoride ion content F in the filtrate was tested. The stability of the defluorinating agents was compared, and the test results are as follows:

[0075] Table 2 Defluorination agent stability comparison experimental data

[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 being placed for 30 days; the defluorination effect of the purchased defluorinating agent B weakened after being placed for 7 days, and the defluorination effect was poor after being placed for 30 days;

[0079] Comparative Examples 1 and 2 respectively use only one of the modified eggshell powder and defatted bone powder dissolved in water to form a liquid defluoridation agent. After being placed for 7 days, the defluoridation effect is slightly weakened. Although the stability is worse than the purchased defluoridation agent B, it is not as good as the emulsion defluoridation agent formed by dissolving the modified mixed powder in water 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. The eggshell powder and defatted bone powder are mixed and then modified to obtain a more uniform and stable modified mixed powder through a physical and chemical reaction. The modified mixed powder is dissolved in a solvent to obtain a more stable homogeneous emulsion defluorinating agent.

[0081] Treatment effect of defluorinating agent on low-temperature and low-turbidity wastewater

[0082] Take 250g of low-temperature and low-turbidity river water with a turbidity of 8.94NTU; divide it into beakers. Add 2.53g of the self-made homogeneous emulsion defluorinating agent A2 (diluted 10 times) 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 program of the test mixer to carry out the flocculation test. After the flocculation test is completed, let it stand for 10 minutes, observe the sedimentation effect of the flocs and test the turbidity of the river water.

[0083] Table 3 Treatment effect of defluorination agent on low temperature and low turbidity wastewater

[0084]

[0085]

[0086] It can be seen from Table 3 that the self-made homogeneous emulsion defluorinating agent of Example 2 has a better flocculation effect on low-temperature and low-turbidity wastewater than the solid defluorinating agent C and the liquid defluorinating agent B, and can significantly reduce the turbidity of the wastewater.

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

Claims

1. A method for preparing a homogeneous emulsion defluorinating agent, characterized in that: The following steps are involved: Step 1: Pretreatment of waste animal bones: remove the meat and fat from the animal bones, dry and crush them to obtain powder F1 for later use; Step 2: Pretreatment of eggshells: Dry the eggshells and crush them to obtain powder F2 for later use; Step 3: preparing a modified mixed powder: mixing powder F1 and powder F2 in a ratio of 1:(2.5-3) and then calcining at high temperature, adding a solvent to the solid mixture after high temperature calcination for hydrothermal treatment, filtering the product after hydrothermal treatment, washing, and drying to obtain a modified mixed powder; Step 4: Prepare a homogeneous emulsion defluorinating agent: dissolve the modified mixed powder in water to obtain a homogeneous emulsion defluorinating agent.

2. The method for preparing a homogeneous emulsion defluorinating agent according to claim 1, characterized in that: The powder F1 crushed in step 1 and the powder F2 crushed in step 2 are sieved, and the powder F1 and powder F2 with a mesh size of 100 to 200 are selected for step 3.

3. The method for preparing a homogeneous emulsion defluorinating agent according to claim 2, characterized in that: In step 4, one or more of aluminum salt, iron salt, magnesium salt and a pH adjuster are added; the pH adjuster is used to adjust the pH of the homogeneous emulsion defluorinating agent to between 3 and 4.

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

5. A method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 4, characterized in that: The animal bone in step 1 is at least one of pig bone, cattle bone, fish bone, sheep bone, dog bone and chicken bone.

6. A method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 4, characterized in that: The eggshell in step 2 is at least one of chicken eggshell, duck eggshell, goose eggshell and quail eggshell.

7. A method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 4, characterized in that: The high temperature calcination is carried out at a high temperature of 450 to 550° C. for 4 to 6 hours; the hydrothermal reaction is carried out at a temperature of 200 to 300° C. for 1 to 3 hours.

8. A method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 4, characterized in that: The bulk density of the modified mixed powder is 0.7-0.8 g / cm 3 .

9. A homogeneous emulsion defluorinating agent prepared by the method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 8.

10. Use of a homogeneous emulsion defluorinating agent prepared by the method for preparing a homogeneous emulsion defluorinating agent according to any one of claims 1 to 8.

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