A defluorination flotation agent, preparation method thereof and application thereof

Abstract

The present invention relates to the technical field of wastewater treatment, and discloses a defluorination flotation agent, a preparation method and an application thereof. The raw materials of the flotation agent include activated alumina, fluoroalkylsilane coupling agent, aminosilane coupling agent and filler; the flotation agent can effectively remove fluoride ions in fluoride-containing wastewater. The fluoride ions can be adsorbed in the activated alumina, and the activated alumina adsorbed with fluoride ions is adsorbed on the water vapor interface generated by the flotation device to form foam and float to the liquid surface and be separated and collected, avoiding the problem of low activity in the chemical treatment after the fluoride-containing precipitate is mixed with sludge. The defluorination flotation agent can also be defluorinated and regenerated, significantly improving the recycling efficiency of fluoride ions.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a defluorination flotation agent, a preparation method thereof and an application thereof. Background Art

[0002] Fluoride-containing industrial wastewater is a common industrial waste, which contains a large amount of highly active fluoride ions. Fluoride 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 is likely to form a fluoride pollution source, which is harmful to the human body and animals. Therefore, fluoride-containing industrial wastewater needs to be treated before it can be discharged.

[0003] Industrial wastewater contains not only a large amount of fluoride ions but also a large amount of organic substances and inorganic salts. Therefore, the treatment of high-organic-matter fluoride-containing industrial wastewater usually requires the combination of multiple processes, such as the Fenton oxidation method and supercritical water oxidation technology for degrading organic substances, the calcium ion precipitation method and activated alumina adsorption method for defluorination, and the A / O process and MBR process for biochemical treatment. In the prior art, there are many treatment technologies for organic fluoride-containing industrial wastewater. For example, the iron-carbon microelectrolysis cell and the organic fluoride-containing wastewater treatment system containing the same with the publication number CN209957615U. In this technical solution, iron-carbon microelectrolysis treatment is combined with the Fenton reaction to oxidize organic fluorides into fluoride ions, and then the precipitation method and adsorption method are used to convert fluoride ions into precipitated sludge, and finally the sludge precipitation is subjected to biochemical treatment. The present application finds that when treating current organic fluoride-containing wastewater, fluoride ion precipitation is usually mixed into the sludge for subsequent biochemical treatment, and fluoride inhibits the activity of enzymes. Therefore, the activity of fluoride-containing precipitation will decrease during biochemical treatment. In addition, calcium fluoride in fluoride ion precipitation has high economic value. Directly mixing fluoride-containing precipitation in the sludge significantly reduces the recycling efficiency of fluoride.

[0004] The key to solving the above problems lies in separating fluoride ions during the fluoride ion precipitation stage so that the fluoride ion precipitation can be removed from the water and not mixed with the sludge, improving the recycling efficiency of fluoride ions and increasing the biological activity of the subsequent biochemical treatment at the same time. Therefore, after consulting relevant materials, those skilled in the art found that the flotation process can achieve the above technical effects. However, 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 highly efficient defluorination flotation agent. Summary of the Invention

[0005] In order to overcome the problems of low recovery and utilization rate of fluoride ions and low biochemical treatment efficiency in the treatment of organic fluorine-containing wastewater in the prior art, the present invention provides a defluorination flotation agent and a preparation method thereof. The defluorination flotation agent can remove fluoride ions in the fluorine-containing wastewater and separate them in the form of flotation foam, without remaining in the sludge, avoiding the inhibitory effect of fluoride precipitation on biochemical treatment, significantly improving the recovery and utilization efficiency of fluoride ions, and improving the activity of biochemical treatment.

[0006] The specific technical solution of the present invention is as follows:

[0007] A defluorination flotation agent, the raw materials of which include activated alumina, fluorine-based silane coupling agent, amino silane coupling agent and filler, and the filler is water.

[0008] Preferably, the concentration of the fluorine-based silane coupling agent is 0.16 - 0.83 mmol / L.

[0009] Preferably, the fluorine-based silane coupling agent is one or more of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane and nonafluorohexyltrimethoxysilane.

[0010] Preferably, the concentration of the amino silane coupling agent is 4.2 - 20.8 mmol / L.

[0011] Preferably, the amino silane coupling agent is one or more of 3-aminopropyltrimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

[0012] Preferably, the particle size of the activated alumina is 800 - 1000 mesh.

[0013] The present invention provides a defluorination flotation agent, which is made of activated alumina, fluorine-based silane coupling agent, amino silane coupling agent and filler as raw materials. The flotation agent can effectively remove fluoride ions in the fluorine-containing wastewater. The fluoride ions can be adsorbed in the activated alumina, and the activated alumina adsorbed with fluoride ions is adsorbed on the water vapor interface generated by the flotation device to form foam and float to the liquid surface and be separated and collected, avoiding the problem of low activity of biochemical treatment after the fluoride precipitation is mixed with the sludge. The defluorination flotation agent can also be regenerated by defluorination, significantly improving the recovery and utilization efficiency of fluoride ions.

[0014] In addition, it is found in this application that the flotation agent obtained by directly modifying activated alumina with a fluoroalkylsilane coupling agent and an aminosilane coupling agent has a poor adsorption effect on fluoride ions. After analysis, it is found that the reason for the above problem is that activated alumina has a porous structure. Therefore, when using the fluoroalkylsilane coupling agent and the aminosilane coupling agent to modify activated alumina, the silane coupling agent will modify the pores of activated alumina, resulting in a significant reduction in its performance of adsorbing fluoride ions. Therefore, in view of the above problem, the present invention uses a filler to fill activated alumina. Activated alumina has strong hydrophilic properties, so water can be used as the filler to fill the pores of activated alumina, and then the filled activated alumina is surface-modified. Since the fluoroalkylsilane coupling agent and the aminosilane coupling agent have poor hydrophilicity, using water as the filler can prevent the organosilane coupling agent from entering the pores of activated alumina, enabling the organosilane coupling agent to only modify the surface of activated alumina. The advantage of choosing water as the filler is that it is easy to remove and has no significant impact on the fluoride-ion adsorption of activated alumina.

[0015] A preparation method of the above-mentioned defluorination flotation agent includes the following steps:

[0016] Step 1: Activated alumina is dispersed in a filler and soaked, and after soaking, it is filtered and dried by suction to obtain modified activated alumina;

[0017] Step 2: The modified activated alumina is dispersed in an organic solvent, and then a fluoroalkylsilane coupling agent is added for reaction to form fluorinated activated alumina;

[0018] Step 3: The fluorinated activated alumina is further dispersed in an organic solvent, and then an aminosilane coupling agent is added for reaction to form fluoroaminated activated alumina;

[0019] Step 4: The fluoroaminated activated alumina is placed for drying and dehydration to prepare the defluorination flotation agent.

[0020] Preferably, the drying temperature in Step 1 is 50 - 80°C.

[0021] Preferably, the drying and dehydration temperature in Step 4 is 150 - 160°C.

[0022] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater includes the following steps: The defluorination flotation agent is added to a flotation device for defluorination treatment, and the flotation device recovers and defluorinates and regenerates the generated foam.

[0023] Compared with the prior art, this application has the following technical effects:

[0024] The present invention provides a defluorination flotation agent, which can effectively remove fluoride ions from fluoride-containing wastewater. The flotation agent can adsorb fluoride ions in activated alumina, and the activated alumina adsorbed with fluoride ions adsorbs on the water-vapor interface generated by the flotation device to form foam, which floats to the liquid surface and is separated and collected, avoiding the problem of low activity in the chemical treatment after the mixture of fluoride-containing precipitate and sludge. The defluorination flotation agent can also be defluorinated and regenerated, significantly improving the recycling efficiency of fluoride ions. Detailed implementation mode

[0025] The present invention will be further described below in conjunction with embodiments.

[0026] Embodiment 1:

[0027] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 900 mesh), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0028] A preparation method of the above-mentioned defluorination flotation agent includes the following steps:

[0029] Step 1: Add 5 parts of activated alumina to 20 parts of deionized water and soak for 3 h. After soaking, carry out suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 3 min to make modified activated alumina;

[0030] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (benzene) to a homogenizer and disperse evenly, then add 0.5 mmol / L of tridecafluorooctyltrimethoxysilane and stir at a rotation speed of 650 rpm at room temperature for 10 h. After stirring, centrifuge to precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluorinated activated alumina;

[0031] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (benzene) and disperse evenly, then add 12.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at a rotation speed of 650 rpm at room temperature for 16 h. After stirring, centrifuge to precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluoroaminated activated alumina;

[0032] Step 4: Dry the fluoroaminated activated alumina prepared above at 150 °C for 2 h to make a defluorination flotation agent.

[0033] An application of the above-mentioned defluorination flotation agent in organic fluoride-containing industrial wastewater includes the following steps:

[0034] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon microelectrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation tank, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped and recovered. After no more foam is generated in the flotation tank, the defluorinated wastewater is introduced into the subsequent flocculation tank. The sludge obtained in the flocculation tank is introduced into the biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. 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] Example 2:

[0036] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 800 mesh), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0037] A preparation method of the above-mentioned defluorination flotation agent, comprising the following steps:

[0038] Step 1: Add 5 parts of activated alumina to 10 parts of deionized water and soak for 2 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 2 min to prepare modified activated alumina;

[0039] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (cyclohexane) to a homogenizer and disperse evenly. Then add 0.4 mmol / L of tridecafluorooctyltrimethoxysilane and stir at a rotation speed of 700 rpm at room temperature for 10 h. After stirring, perform centrifugal precipitation, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluorinated activated alumina;

[0040] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (cyclohexane) and disperse evenly. Then add 10.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at a rotation speed of 700 rpm at room temperature for 16 h. After stirring, perform centrifugal precipitation, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluoroaminated activated alumina;

[0041] Step 4: Place the fluoroaminated activated alumina prepared above at 150 °C and dry for 2 h to prepare the defluorination flotation agent.

[0042] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, comprising the following steps:

[0043] The organic fluorine-containing industrial wastewater is fed into an oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is fed into a flotation pool, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped and recovered. After no more foam is generated in the flotation pool, the defluorinated wastewater is fed into the subsequent flocculation pool. The sludge obtained in the flocculation pool is fed into a biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used for the production of products such as calcium fluoride.

[0044] Example 3:

[0045] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 1000 mesh), tridecafluorooctyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0046] A preparation method of the above-mentioned defluorination flotation agent, comprising the following steps:

[0047] Step 1: Add 5 parts of activated alumina to 10 parts of deionized water and soak for 2 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 2 min to prepare modified activated alumina;

[0048] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (cyclohexane) to a homogenizer and disperse evenly. Then add 0.6 mmol / L of tridecafluorooctyltrimethoxysilane and stir at 800 rpm at room temperature for 10 h. After stirring, perform centrifugal precipitation, and then use anhydrous ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluorinated activated alumina;

[0049] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (cyclohexane) and disperse evenly. Then add 14 mmol / L of 3-aminopropyltrimethoxysilane and stir at 800 rpm at room temperature for 15 h. After stirring, perform centrifugal precipitation, and then use anhydrous ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluoroaminated activated alumina;

[0050] Step 4: Place the fluoroaminated activated alumina prepared above at 160 °C and dry for 1 h to prepare the defluorination flotation agent.

[0051] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, comprising the following steps:

[0052] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon microelectrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation pool, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped and recovered. After no more foam is generated in the flotation pool, the defluorinated wastewater is introduced into the subsequent flocculation pool. The sludge obtained in the flocculation pool is introduced into the biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0053] Example 4:

[0054] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 900 mesh), heptadecafluorodecyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane and water.

[0055] A preparation method of the above-mentioned defluorination flotation agent, comprising the following steps:

[0056] Step 1: Add 5 parts of activated alumina to 20 parts of deionized water and soak for 3 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 3 min to prepare modified activated alumina;

[0057] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (toluene) to a homogenizer and disperse evenly. Then add 0.16 mmol / L of heptadecafluorodecyltrimethoxysilane and stir at 650 rpm at room temperature for 10 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluorinated activated alumina;

[0058] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (toluene) and disperse evenly. Then add 4.2 mmol / L of 3-(2-aminoethylamino)propyltrimethoxysilane and stir at 650 rpm at room temperature for 16 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluoroaminated activated alumina;

[0059] Step 4: Place the above-prepared fluoroaminated activated alumina at 150 °C and dry for 2 h to prepare the defluorination flotation agent.

[0060] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, comprising the following steps:

[0061] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon microelectrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation tank, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped and recovered. After no more foam is generated in the flotation tank, the defluorinated wastewater is introduced into the subsequent flocculation tank. The sludge obtained in the flocculation tank is introduced into the biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used for the production of products such as calcium fluoride.

[0062] Example 5:

[0063] A defluorination flotation agent, the raw materials include activated alumina (particle size of 900 mesh), nonafluorohexyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0064] A preparation method of the above-mentioned defluorination flotation agent, including the following steps:

[0065] Step 1: Add 5 parts of activated alumina to 20 parts of deionized water and soak for 3 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 3 min to prepare modified activated alumina;

[0066] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of organic solvent (xylene) to a homogenizer and disperse evenly. Then add 0.83 mmol / L of nonafluorohexyltrimethoxysilane and stir at 650 rpm at room temperature for 10 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluorinated activated alumina;

[0067] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of organic solvent (xylene) and disperse evenly. Then add 20.8 mmol / L of 3-aminopropyltrimethoxysilane and stir at 650 rpm at room temperature for 16 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluoroaminated activated alumina;

[0068] Step 4: Place the above-mentioned prepared fluoroaminated activated alumina at 150 °C and dry for 2 h to prepare the defluorination flotation agent.

[0069] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, including the following steps:

[0070] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon microelectrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation tank, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped off and recovered. After no more foam is generated in the flotation tank, the defluorinated wastewater is introduced into the subsequent flocculation tank. The sludge obtained in the flocculation tank is introduced into the biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0071] Example 6:

[0072] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 900 mesh), heptadecafluorodecyltrimethoxysilane, 3-aminopropyltrimethoxysilane and water.

[0073] A preparation method of the above-mentioned defluorination flotation agent, comprising the following steps:

[0074] Step 1: Add 5 parts of activated alumina to 20 parts of deionized water and soak for 3 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 3 min to prepare modified activated alumina;

[0075] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (cyclohexanone) to a homogenizer and disperse evenly. Then add 0.23 mmol / L of heptadecafluorodecyltrimethoxysilane and stir at 650 rpm at room temperature for 10 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluorinated activated alumina;

[0076] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (cyclohexanone) and disperse evenly. Then add 12.5 mmol / L of 3-aminopropyltrimethoxysilane and stir at 650 rpm at room temperature for 16 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to prepare fluoroaminated activated alumina;

[0077] Step 4: Place the above-prepared fluoroaminated activated alumina at 150 °C and dry for 2 h to prepare the defluorination flotation agent.

[0078] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, comprising the following steps:

[0079] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon microelectrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation tank, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped off and recycled. After no more foam is generated in the flotation tank, the defluorinated wastewater is introduced into the subsequent flocculation tank. The sludge obtained in the flocculation tank is introduced into the biochemical unit for deep decomposition. The recycled foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0080] Example 7:

[0081] A defluorination flotation agent, the raw materials of which include activated alumina (particle size of 900 mesh), nonafluorohexyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane and water.

[0082] A preparation method of the above-mentioned defluorination flotation agent, comprising the following steps:

[0083] Step 1: Add 5 parts of activated alumina to 20 parts of deionized water and soak for 3 h. After soaking, perform suction filtration to collect the activated alumina, and dry the collected activated alumina at 50 °C for 3 min to prepare modified activated alumina;

[0084] Step 2: Add 5 g of the above-mentioned modified activated alumina and 40 ml of an organic solvent (benzene) to a homogenizer and disperse evenly. Then add 0.85 mmol / L of nonafluorohexyltrimethoxysilane and stir at a rotation speed of 650 rpm at room temperature for 10 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluorinated activated alumina;

[0085] Step 3: Add 0.5 g of the above-mentioned fluorinated activated alumina to 50 ml of an organic solvent (benzene) and disperse evenly. Then add 5.5 mmol / L of 3-(2-aminoethylamino)propyltrimethoxysilane and stir at a rotation speed of 650 rpm at room temperature for 16 h. After stirring, centrifuge and precipitate, and then use absolute ethanol to disperse, wash and centrifuge the precipitate three times. The obtained precipitate is dried at 60 °C to obtain fluoroaminated activated alumina;

[0086] Step 4: Dry the fluoroaminated activated alumina prepared above at 150 °C for 2 h to prepare the defluorination flotation agent.

[0087] An application of the above-mentioned defluorination flotation agent in organic fluorine-containing industrial wastewater, comprising the following steps:

[0088] The organic fluorine-containing industrial wastewater is introduced into the oxidation unit (iron-carbon micro-electrolysis reaction and Fenton reaction unit) for treatment to obtain fluoride ion wastewater. The fluoride ion wastewater is introduced into the flotation tank, and the above-mentioned defluorination flotation agent is added. The generated foam is scraped and recovered. After no more foam is generated in the flotation tank, the defluorinated wastewater is introduced into the subsequent flocculation tank. The sludge obtained in the flocculation tank is introduced into the biochemical unit for deep decomposition. The recovered foam is defluorinated and regenerated with aluminum sulfate. The regenerated defluorination flotation agent can be used again, and the removed fluoride ions can be used to produce products such as calcium fluoride.

[0089] Comparative Example 1:

[0090] Compared with Example 1, in Comparative Example 1, Steps 1 and 4 were not carried out, and the other conditions were the same as those in Example 1.

[0091] Comparative Example 2:

[0092] Compared with Example 1, in Comparative Example 2, the drying temperature in Step 1 was 150 °C, and the other conditions were the same as those in Example 1.

[0093] Comparative Example 3:

[0094] Compared with Example 1, in Comparative Example 3, Step 4 was not carried out, and the other conditions were the same as those in Example 1.

[0095] Comparative Example 4:

[0096] Compared with Example 1, in Comparative Example 4, the drying temperature in Step 4 was 80 °C, and the other conditions were the same as those in Example 1.

[0097] Detection Example 1:

[0098] 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;

[0099] Steps for testing the adsorption capacity: Place 1 g of the defluorination flotation agent in 60 ml of an aqueous sodium fluoride solution (the initial concentration of sodium fluoride is 5 - 95 mg / L), oscillate and adsorb at 20 °C for 10 h. After the adsorption ends, use an ion chromatograph to test the fluoride ion content in the adsorbed sodium fluoride solution, and calculate the difference between the initial fluoride ion concentration and the adsorbed fluoride ion concentration to obtain the adsorption capacity of the defluorination flotation agent;

[0100] Regeneration performance test steps: Place 1 g of defluorination flotation agent in 60 ml of sodium fluoride aqueous solution (the initial concentration of sodium fluoride is 10 mg / L), oscillate and adsorb for 10 h at 20 °C. After the defluorination flotation agent is saturated with adsorption, place the saturated defluorination flotation agent in a 10 wt% aluminum sulfate solution, desorb and regenerate at 20 °C for 30 min, wash it clean with deionized water, and then put it into the sodium fluoride aqueous solution with an initial concentration of 10 mg / L again for adsorption. Use an ion chromatograph to test the fluoride ion content in the sodium fluoride solution after adsorption, and test the adsorption capacity of the material before and after regeneration;

[0101] The test results are shown in Table 1;

[0102] Table 1 Antimildew agent antibacterial performance

[0103]

[0104]

[0105] As shown in Table 1, the adsorption capacity of the defluorination flotation agents prepared in Examples 1 to 7 for fluoride ions is 2.31 - 2.81 mg / g. There is no significant difference in the adsorption capacity of the defluorination flotation agent regenerated once for fluoride ions, and there is also no significant difference in the adsorption capacity of the defluorination flotation agent regenerated 5 times for fluoride ions. The above results show that the defluorination flotation agent prepared by the present invention has excellent fluoride ion adsorption performance, and the regeneration performance of this defluorination flotation agent is excellent and can be reused multiple times.

[0106] In Comparative Example 1, activated alumina was not treated with a filler, and its adsorption capacity for fluoride ions was only 0.43 mg / g. Compared with Example 1, when the internal pore structure of activated alumina was not filled with a filler, the adsorption effect of the obtained defluorination flotation agent on fluoride ions was poor. The reason is that the surface and pore structure of the activated alumina untreated 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 being unable to contact the aqueous solution and exchange with the fluoride ions in the aqueous solution in the fluoride ion aqueous solution, thus significantly reducing its fluoride ion adsorption capacity. However, in the examples of the present invention, for the activated alumina filled with a filler, when the silane coupling agent is used for modification, the filler can prevent the silane coupling agent from modifying the internal pore structure of the activated alumina, enabling only surface modification of the activated alumina. The surface-modified activated alumina also has certain performance and can have flotation performance. In addition, since the inside of the activated alumina is not modified by the silane coupling agent, its internal hydrophilicity is relatively strong. Therefore, when flotation is carried out, the aqueous solution containing fluoride ions can be adsorbed into the voids inside the activated alumina for fluoride ion exchange, thus significantly increasing the adsorption capacity of the defluorination flotation agent for fluoride ions.

[0107] In Comparative Example 2, the modified activated alumina in Step 1 was dried at 150°C. 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.

[0108] In Comparative Example 3, the filler was not removed from the fluorinated and ammoniated activated alumina, and in Comparative Example 4, the removal temperature of the fluorinated and ammoniated activated alumina was too low, both of which would cause the filler to be unable to be removed from the inside of the fluorinated and ammoniated activated alumina, resulting in the prepared defluorination flotation agent being unable to effectively adsorb fluoride ions.

[0109] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a defluorination flotation agent, characterized in that It includes the following steps: Step 1: Activated alumina is dispersed and soaked in a filler, and after the soaking is completed, it is filtered by suction and dried to obtain modified activated alumina. The drying temperature is 50 - 80 °C, and the filler is water; Step 2: The modified activated alumina is dispersed in an organic solvent, and then a fluoroalkylsilane coupling agent is added for reaction to prepare fluorinated activated alumina; Step 3: Then the fluorinated activated alumina is dispersed in an organic solvent, and then an aminosilane coupling agent is added for reaction to prepare fluoroaminated activated alumina; Step 4: The fluoroaminated activated alumina is placed for drying and dehydration to prepare a defluorination flotation agent, and the temperature of drying and dehydration is 150 - 160 °C.

2. The preparation method according to claim 1, characterized in that, The concentration of the fluoroalkylsilane coupling agent is 0.16 - 0.83 mmol / L.

3. The preparation method according to claim 1 or 2, characterized in that, The fluoroalkylsilane coupling agent is one or several of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, and nonafluorohexyltrimethoxysilane.

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

5. The preparation method according to claim 1 or 4, characterized in that, The aminosilane coupling agent is one of 3-aminopropyltrimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

6. The preparation method according to claim 1, characterized in that, The particle size of the activated alumina is 800 - 1000 mesh.

7. Application of a defluorination flotation agent, characterized in that It includes the following steps: The defluorination flotation agent is added to a flotation device for defluorination treatment, and the flotation device recovers and regenerates the defluorinated foam. The defluorination flotation agent is prepared by the preparation method of the defluorination flotation agent according to any one of claims 1 to 6.

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