Defluorination flotation agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of wastewater treatment, and discloses a defluorination flotation agent as well as a preparation method and application thereof, the flotation agent comprises the following raw materials: activated aluminum oxide, a fluorine-based silane coupling agent, an amino silane coupling agent and a filling agent; the flotation agent can effectively remove fluorine ions in fluorine-containing wastewater, the flotation agent can adsorb the fluorine ions in activated aluminum oxide, the activated aluminum oxide adsorbing the fluorine ions is adsorbed on a water vapor interface generated by a flotation device to form foam, and the foam floats to the surface of liquid and is separated and collected. The problem of low chemical treatment activity after the fluorine-containing precipitate and the sludge are blended is avoided, the fluorine removal flotation agent can also be used for defluorination regeneration, and the fluorine ion recycling efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a fluorine removal flotation agent, a preparation method and application thereof. Background Art

[0002] Fluoride-containing industrial wastewater is a common industrial waste, which contains a large amount of highly active fluoride ions. Fluorine is one of the essential trace elements for the human body, but excessive intake of fluoride can cause skeletal fluorosis, dental fluorosis, etc. Direct discharge of fluoride-containing industrial wastewater can easily cause the formation of fluoride pollution sources, which is harmful to humans and animals. Therefore, fluoride-containing industrial wastewater needs to be treated before it can be discharged.

[0003] In addition to a large amount of fluoride ions, industrial wastewater also contains a large amount of organic matter and inorganic salts. Therefore, the treatment of high-organic fluoride industrial wastewater usually requires a combination of multiple processes, such as the Fenton oxidation method and supercritical water oxidation technology for degrading organic matter, the calcium ion precipitation method and activated alumina adsorption method for defluorination, and the A / O process and MBR process for biochemical treatment. There are many treatment technologies for organic fluoride-containing industrial wastewater in the prior art, such as the iron-carbon micro-electrolysis cell and the organic fluoride wastewater treatment system containing it, which is published in CN209957615U. This technical solution adopts The iron-carbon micro-electrolysis treatment is combined with the Fenton reaction to oxidize organic fluorides into fluoride ions, and then the fluoride ions are converted into precipitated sludge by precipitation and adsorption methods, and finally the sludge precipitate is subjected to biochemical treatment; the present application finds that in the current treatment of organic fluoride-containing wastewater, the fluoride ion precipitate is usually mixed into the sludge for subsequent biochemical treatment, and fluorine has an inhibitory effect on the activity of enzymes, so the activity of the fluoride-containing precipitate will be reduced during the biochemical treatment. In addition, the calcium fluoride in the fluoride ion precipitate has a high economic value. Directly mixing the fluoride-containing precipitate into the sludge significantly reduces the efficiency of fluorine recovery and utilization.

[0004] The key to solving the above problems is to separate the fluoride ions in the fluoride ion precipitation stage so that the fluoride ion precipitate can be removed from the water and not mixed with the sludge, thereby improving the recovery efficiency of fluoride ions and increasing the biological activity of the back-end biochemical treatment. Therefore, after consulting relevant information, technical personnel in this field found that the flotation process can achieve the above technical effects, but the core of the flotation process is the flotation agent, and the performance of the flotation agent can significantly improve the separation efficiency. Therefore, it is of great significance to provide a high-efficiency fluoride removal flotation agent. Summary of the invention

[0005] In order to overcome the problems of low fluoride ion recovery and utilization rate and low biochemical treatment efficiency in the prior art for treating organic fluoride-containing wastewater, the present invention provides a defluorination flotation agent and a preparation method thereof. The defluorination flotation agent can remove fluoride ions from fluoride-containing wastewater and separate them in the form of flotation foam, and will not remain in the sludge, thereby avoiding the inhibitory effect of fluoride precipitation on biochemical treatment, significantly improving the recovery and utilization efficiency of fluoride ions and improving the biochemical treatment activity.

[0006] The specific technical scheme of the present invention is: A fluorine removal flotation agent, the raw materials of which include activated alumina, a fluorine-based silane coupling agent, an aminosilane coupling agent and a filler, wherein the filler is water.

[0007] Preferably, the concentration of the fluorine-based silane coupling agent is 0.16-0.83 mmol / L.

[0008] Preferably, the fluorine-based silane coupling agent is one or more of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane and nonafluorohexyltrimethoxysilane.

[0009] Preferably, the concentration of the aminosilane coupling agent is 4.2-20.8 mmol / L.

[0010] Preferably, the aminosilane coupling agent is one or more of 3-aminopropyltrimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

[0011] Preferably, the particle size of the activated alumina is 800-1000 mesh.

[0012] The invention provides a fluorine removal flotation agent. The flotation agent is made of activated alumina, fluorine-based silane coupling agent, aminosilane coupling agent and filler as raw materials. The flotation agent can effectively remove fluorine ions in fluorine-containing wastewater. The flotation agent can adsorb fluorine ions in the activated alumina. The activated alumina adsorbing fluorine ions is adsorbed on the water vapor interface generated by a flotation device to form foam that floats to the liquid surface and is separated and collected, thereby avoiding the problem of low activity of post-treatment of fluorine-containing precipitation and sludge. The fluorine removal flotation agent can also defluorinate and regenerate, thereby significantly improving the recovery and utilization efficiency of fluorine ions.

[0013] In addition, the present application found that the flotation agent obtained by directly modifying the activated alumina with a fluorine-based silane coupling agent and an aminosilane coupling agent has a poor adsorption effect on fluoride ions. After analysis, it was found that the reason for the above problem is that the activated alumina has a porous structure. Therefore, when the activated alumina is modified with a fluorine-based silane coupling agent and an aminosilane coupling agent, the silane coupling agent will modify the pores of the activated alumina, resulting in a significant decrease in its ability to adsorb fluoride ions. Therefore, in order to solve the above problem, the present invention adopts a filler to modify the activated alumina. Aluminum is used for filling. Activated alumina has strong hydrophilic properties, so water can be used as a filler to fill the pores of the activated alumina, and then the surface of the filled activated alumina is modified. Since the fluorine-based silane coupling agent and the aminosilane coupling agent have poor hydrophilicity, using water as a filler can prevent the organic silane coupling agent from entering the pores of the activated alumina, so that the organic silane coupling agent only modifies the surface of the activated alumina. The advantage of choosing water as a filler is that it is easy to remove and has no significant effect on the adsorption of fluoride ions by the activated alumina.

[0014] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: The activated alumina is dispersed in the filler and soaked, and after the soaking is completed, the modified activated alumina is obtained by suction filtration and drying; Step 2: dispersing the modified activated alumina in an organic solvent, and then adding a fluorinated silane coupling agent to react to prepare fluorinated activated alumina; Step 3: dispersing the fluorinated activated alumina in an organic solvent, and then adding an aminosilane coupling agent to react to prepare fluorinated activated alumina; Step 4: Dry and dehydrate the fluorinated activated alumina to prepare a fluoride removal flotation agent.

[0015] Preferably, the drying temperature in step 1 is 50-80°C.

[0016] Preferably, the drying and dehydration temperature in step 4 is 150-160°C.

[0017] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: adding the defluorination flotation agent to a flotation device for defluorination treatment, and the flotation device recovers and defluorinates the generated foam.

[0018] Compared with the prior art, this application has the following technical effects: The present invention provides a defluorination flotation agent, which can effectively remove fluoride ions in fluoride-containing wastewater. The flotation agent can adsorb fluoride ions in activated alumina. The activated alumina adsorbing fluoride ions is adsorbed on the water vapor interface generated by a flotation device to form foam that floats to the liquid surface and is separated and collected, thereby avoiding the problem of low activity of post-treatment of fluoride-containing precipitation and sludge mixed together. The defluorination flotation agent can also defluorinate and regenerate, thereby significantly improving the recovery and utilization efficiency of fluoride ions. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the embodiments.

[0020] Embodiment 1: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 900 meshes), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0021] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 20 parts of deionized water and soak for 3 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 3 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of organic solvent (benzene) into a homogenizer and disperse them evenly, then add 0.5mmol / L of tridecafluorooctyltrimethoxysilane and stir at room temperature for 10h at a speed of 650rpm. After stirring, centrifuge and precipitate. Then use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (benzene) and disperse evenly, then add 12.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at room temperature for 16 hours at a speed of 650 rpm. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0022] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0023] Embodiment 2: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 800 meshes), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0024] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 10 parts of deionized water and soak for 2 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 2 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of an organic solvent (cyclohexane) into a homogenizer and disperse evenly, then add 0.4mmol / L of tridecafluorooctyltrimethoxysilane and stir at room temperature at a speed of 700rpm for 10h, centrifuge and precipitate after stirring, then use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina; Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (cyclohexane) and disperse evenly, then add 10.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at room temperature for 16 hours at a speed of 700 rpm. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0025] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0026] Embodiment 3: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 1000 meshes), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0027] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 10 parts of deionized water and soak for 2 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 2 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of an organic solvent (cyclohexane) into a homogenizer and disperse evenly, then add 0.6mmol / L of tridecafluorooctyltrimethoxysilane and stir at room temperature at a speed of 800rpm for 10h, centrifuge and precipitate after stirring, then use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina; Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (cyclohexane) and disperse evenly, then add 14 mmol / L of 3-aminopropyltrimethoxysilane and stir at room temperature at a speed of 800 rpm for 15 h. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60° C. to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 160° C. for 1 hour to prepare a defluorination flotation agent.

[0028] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0029] Embodiment 4: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 900 meshes), heptadecafluorodecyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane and water.

[0030] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 20 parts of deionized water and soak for 3 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 3 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of an organic solvent (toluene) into a homogenizer and disperse them evenly, then add 0.16mmol / L of heptadecafluorodecyltrimethoxysilane and stir at room temperature at a speed of 650rpm for 10h. After stirring, centrifuge and precipitate. Then use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (toluene) and disperse evenly, then add 4.2 mmol / L of 3-(2-aminoethylamino)propyltrimethoxysilane and stir at room temperature for 16 hours at a speed of 650 rpm. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0031] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0032] Embodiment 5: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 900 meshes), nonafluorohexyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0033] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 20 parts of deionized water and soak for 3 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 3 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of an organic solvent (xylene) into a homogenizer and disperse them evenly, then add 0.83mmol / L of nonafluorohexyltrimethoxysilane and stir at room temperature for 10h at a speed of 650rpm. After stirring, centrifuge and precipitate. Then use anhydrous ethanol to disperse, wash and centrifuge the precipitate. Repeat three times. The obtained precipitate is dried at 60°C to obtain fluorinated activated alumina. Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (xylene) and disperse evenly, then add 20.8 mmol / L of 3-aminopropyltrimethoxysilane and stir at room temperature for 16 hours at a speed of 650 rpm. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0034] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0035] Embodiment 6: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 900 meshes), heptadecafluorodecyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0036] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 20 parts of deionized water and soak for 3 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 3 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of an organic solvent (cyclohexanone) into a homogenizer and disperse them evenly, then add 0.23mmol / L of heptadecafluorodecyltrimethoxysilane and stir at room temperature at a speed of 650rpm for 10h. Centrifuge and precipitate after stirring. Use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the precipitate at 60°C to obtain fluorinated activated alumina. Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (cyclohexanone) and disperse evenly, then add 12.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at room temperature for 16 hours at a speed of 650 rpm. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0037] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0038] Embodiment 7: A fluorine removal flotation agent, the raw materials of which include activated alumina (with a particle size of 900 meshes), nonafluorohexyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane and water.

[0039] A method for preparing the above-mentioned defluorination flotation agent comprises the following steps: Step 1: Add 5 parts of activated alumina into 20 parts of deionized water and soak for 3 hours. After soaking, collect the activated alumina by filtration, and dry the collected activated alumina at 50° C. for 3 minutes to prepare modified activated alumina. Step 2: Add 5g of the modified activated alumina and 40ml of organic solvent (benzene) into a homogenizer and disperse them evenly, then add 0.85mmol / L of nonafluorohexyltrimethoxysilane and stir at room temperature for 10h at a speed of 650rpm. After stirring, centrifuge and precipitate. Then use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina into 50 ml of an organic solvent (benzene) and disperse evenly, then add 5.5 mmol / L of 3-(2-aminoethylamino)propyltrimethoxysilane and stir at room temperature and speed of 650 rpm for 16 hours. After stirring, centrifuge and precipitate. Then, use anhydrous ethanol to disperse, wash and centrifuge the precipitate, repeat three times, and dry the obtained precipitate at 60°C to obtain fluorinated activated alumina. Step 4: Dry the fluorinated activated alumina prepared above at 150° C. for 2 hours to prepare a defluorination flotation agent.

[0040] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater comprises the following steps: The organic fluorine-containing industrial wastewater is passed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater, which is then passed into a flotation tank, and the above-mentioned defluorination flotation agent is added to scrape off and recover the generated foam. After no more foam is generated in the flotation tank, the defluorination wastewater is passed into a subsequent flocculation tank, and the sludge obtained in the flocculation tank is passed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated using aluminum sulfate, and the regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0041] Comparative Example 1: Compared with Example 1, step 1 and step 4 were not performed in Comparative Example 1, and the other conditions were the same as those in Example 1.

[0042] Comparative Example 2: Compared with Example 1, the drying temperature in step 1 in Comparative Example 2 is 150° C., and the other conditions are the same as those in Example 1.

[0043] Comparative Example 3: Compared with Example 1, step 4 was not performed in Comparative Example 3, and the other conditions were the same as those in Example 1.

[0044] Comparative Example 4: Compared with Example 1, the drying temperature in step 4 in Comparative Example 4 is 80° C., and the other conditions are the same as those in Example 1.

[0045] Test example 1: The adsorption capacity and regeneration performance of the defluorination flotation agents prepared in Examples 1 to 7 and Comparative Examples 1 and 4 were tested; Adsorption capacity test steps: 1g of defluorination flotation agent is placed in 60ml of sodium fluoride aqueous solution (initial concentration of sodium fluoride is 5-95mg / L) and oscillated for adsorption at 20°C for 10h. After the adsorption is completed, the fluoride ion content in the sodium fluoride solution after adsorption is tested using an ion chromatograph, and the difference between the initial fluoride ion concentration and the fluoride ion concentration after adsorption is calculated to obtain the adsorption capacity of the defluorination flotation agent; Regeneration performance test steps: 1g of defluorination flotation agent is placed in 60ml of sodium fluoride aqueous solution (the initial concentration of sodium fluoride is 10mg / L) and oscillated adsorbed at 20°C for 10h. After the defluorination flotation agent is saturated with adsorption, the saturated defluorination flotation agent is placed in a 10wt% aluminum sulfate solution, desorbed and regenerated at 20°C for 30min, and washed with deionized water. Then, the agent is placed in a sodium fluoride aqueous solution with an initial concentration of 10mg / L for adsorption again. The fluoride ion content in the sodium fluoride solution after adsorption is tested using an ion chromatograph, and the adsorption capacity of the test material before and after regeneration is tested; The test results are shown in Table 1; Table 1 Antibacterial properties of mildew inhibitors As shown in Table 1, the adsorption capacity of fluoride ions of the defluoridation flotation agents prepared in Examples 1 to 7 is 2.31-2.81 mg / g, and there is no significant difference in the adsorption capacity of fluoride ions of the defluoridation flotation agents regenerated once, and there is no significant difference in the adsorption capacity of fluoride ions of the defluoridation flotation agents regenerated five times. The above results show that the defluoridation flotation agent prepared by the present invention has excellent fluoride ion adsorption performance, and the defluoridation flotation agent has excellent regeneration performance and can be reused many times.

[0046] In Comparative Example 1, no filler was used to treat the activated alumina, and its adsorption capacity for fluoride ions was only 0.43 mg / g. Compared with Example 1, when the filler was not used to fill the internal pore structure of the activated alumina, the adsorption effect of the defluorination flotation agent on fluoride ions was poor. The reason is that the surface and pore structure of the activated alumina that has not been treated with the filler will be modified by the silane coupling agent, which significantly reduces the hydrophilicity of the modified part, resulting in the internal pore structure of the activated alumina in the fluoride ion aqueous solution unable to contact the aqueous solution and exchange with the fluoride ions in the aqueous solution, so that it adsorbs fluoride ions. The capacity of the activated alumina is significantly reduced, while the activated alumina filled with fillers in the embodiment of the present invention can prevent the silane coupling agent from modifying the internal pore structure of the activated alumina during the modification with the silane coupling agent, so that the activated alumina can only achieve surface modification. The surface-modified activated alumina also has a girder property and can have flotation performance. In addition, since the interior of the activated alumina is not modified by the silane coupling agent, its internal hydrophilicity is relatively strong. Therefore, during flotation, the aqueous solution containing fluoride ions can be adsorbed into the voids of the activated alumina for fluoride ion exchange, thereby significantly improving the adsorption capacity of the defluorination flotation agent for fluoride ions.

[0047] In Comparative Example 2, 150°C was used to dry the modified activated alumina in step 1. The results showed that too high a drying temperature would cause the internal filler of the activated alumina to escape, resulting in incomplete filling of the filler and reducing the adsorption capacity of the defluorination flotation agent for fluoride ions.

[0048] In Comparative Example 3, the filler was not removed from the fluorinated activated alumina, and in Comparative Example 4, the removal temperature of the fluorinated activated alumina was too low, both of which resulted in the filler being unable to be removed from the interior of the fluorinated activated alumina, resulting in the inability of the prepared defluorination flotation agent to effectively adsorb fluoride ions.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A fluorine removal flotation agent, characterized in that: The raw materials include activated alumina, fluorine-based silane coupling agent, aminosilane coupling agent and filler. The filler is filled into the activated alumina to prepare modified activated alumina. The fluorine-based silane coupling agent and aminosilane coupling agent are hydrophobically grafted to the surface of the modified activated alumina to prepare fluorinated activated alumina. The fluorinated activated alumina is dried to remove the filler to prepare a defluorination flotation agent. The filler is water.

2. The defluorination flotation agent according to claim 1, characterized in that: The concentration of the fluorine-based silane coupling agent is 0.16-0.83 mmol / L.

3. The defluorination flotation agent according to claim 1 or 2, characterized in that: The fluorine-based silane coupling agent is one or more of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane and nonafluorohexyltrimethoxysilane.

4. The defluorination flotation agent according to claim 1, characterized in that: The concentration of the aminosilane coupling agent is 4.2-20.8 mmol / L.

5. The defluorination flotation agent according to claim 1 or 4, characterized in that: The aminosilane coupling agent is an aminosilane selected from 3-aminopropyltrimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

6. The defluorination flotation agent according to claim 1, characterized in that: The particle size of the activated alumina is 800-1000 mesh.

7. A method for preparing a defluorination flotation agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: The activated alumina is dispersed in the filler and soaked, and after the soaking is completed, the modified activated alumina is obtained by suction filtration and drying; Step 2: dispersing the modified activated alumina in an organic solvent, and then adding a fluorinated silane coupling agent to react to prepare fluorinated activated alumina; Step 3: dispersing the fluorinated activated alumina in an organic solvent, and then adding an aminosilane coupling agent to react to prepare fluorinated activated alumina; Step 4: Dry and dehydrate the fluorinated activated alumina to prepare a fluoride removal flotation agent.

8. The preparation method according to claim 7, characterized in that: The drying temperature in step 1 is 50-80°C.

9. The preparation method according to claim 7, characterized in that: The drying and dehydration temperature in step 4 is 150-160°C.

10. An application of the defluorination flotation agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: The defluorination flotation agent is added to the flotation device for defluorination treatment, and the flotation device recovers the generated foam for defluorination regeneration.

Images