Method for removing fluorine ions in water body

Abstract

The invention relates to the technical field of water treatment, in particular to a method for removing fluorine ions in a water body, which comprises the following steps: adding iron ions, aluminum ions and fluorine ions to form a stable complex, so as to change the chemical properties and behaviors of the fluorine ions, thereby influencing the migration behavior of the fluorine ions in chemical reaction and environment; in the removal of the fluorine ions, metal complexing agents including iron ions, aluminum ions and the like are added to form hexafluoroferrite ions or hexafluoroaluminate ion complexes, so that the chemical properties and behaviors of the fluorine ions are changed; the hexafluoroferrate ions or hexafluoroaluminate ions in the water body are adsorbed by the functionalized nanofibers, so that the fluorine ions in the fluorine-containing water body can be removed; and then the functional nanofiber can be recycled through desorption and regeneration.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a method for removing fluoride ions in water. Background Art

[0002] Water treatment technology is an important branch of environmental engineering and chemical engineering, covering a variety of methods and technical systems aimed at improving water quality and removing harmful substances.

[0003] Fluoride ion is a common pollutant in drinking water and industrial water, and its excessive intake can have adverse effects on human health; therefore, the development of effective fluoride ion removal technology is crucial to ensuring water quality safety and public health. Summary of the invention

[0004] The purpose of the present invention is to provide a method for removing fluoride ions in water, so as to solve the problem that fluoride ions are a common pollutant in drinking water and industrial water in the prior art, and excessive intake of fluoride ions can have adverse effects on human health; therefore, the development of effective fluoride ion removal technology is crucial to ensure water quality safety and human health.

[0005] To achieve the above object, the present invention provides a method for removing fluoride ions in water, the method for removing fluoride ions in water comprising the following steps:

[0006] S1: adding alkaline solution or acid solution to adjust the pH value of the fluoride ion-containing water body;

[0007] S2: adding iron ions and aluminum ions;

[0008] S3: adding functionalized nanofibers to remove fluoride ions indirectly from fluoridated water;

[0009] S4: soaking the functionalized nanofibers after adsorption saturation in a 1-4 mol / L sulfuric acid aqueous solution for desorption;

[0010] S5: Soaking in a 0.5-2 mol / L sodium hydroxide aqueous solution to achieve regeneration of the functionalized nanofibers.

[0011] Wherein, in step S1, the pH value is in the range of 1.0 to 7.0.

[0012] Wherein, in step S2, the iron ion source is one or a mixture of ferric sulfate, ferric chloride or ferric nitrate.

[0013] Wherein, in step S2, the aluminum ion source is one or a mixture of aluminum chloride hexahydrate, aluminum sulfate or aluminum nitrate.

[0014] Wherein, in step S2, the fluoride ions interact with the iron ions to form a hexafluoroferrate ion complex.

[0015] Wherein, in step S2, the fluoride ions interact with the aluminum ions to form a hexafluoroaluminate ion complex.

[0016] Wherein, in step S3, the functionalized nanofibers adsorb the hexafluoroferrate ions or the hexafluoroaluminate ions to indirectly remove fluoride ions from the fluoride-containing water body.

[0017] The present invention discloses a method for removing fluoride ions from water. The method comprises adding the iron ions and the aluminum ions to form a stable complex with the fluoride ions to change the chemical properties and behaviors of the fluoride ions, thereby affecting the migration behaviors of the fluoride ions in chemical reactions and the environment. In the removal of the fluoride ions, a metal complexing agent including the iron ions and the aluminum ions is added to form a complex of the hexafluoroferrate ions or the hexafluoroaluminate ions to change the chemical properties and behaviors of the fluoride ions. The functionalized nanofibers adsorb the hexafluoroferrate ions or the hexafluoroaluminate ions in the water to remove the fluoride ions in the fluoride-containing water. The functionalized nanofibers can be recycled by desorption and regeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a flow chart of the steps of the present invention.

[0020] Figure 2 This is a graph showing the effect of pH value on fluoride ion adsorption performance in the present invention.

[0021] Figure 3 It is the adsorption isotherm diagram of the functionalized nanofibers of the present invention to fluoride-containing water.

[0022] Figure 4 This is a diagram of the adsorption kinetics of fluoride-containing water by the functionalized nanofibers of the present invention.

[0023] Figure 5 This is a graph showing the cyclic regeneration performance of the functionalized nanofibers in the present invention in removing fluoride ions.

[0024] Figure 6 It is a schematic diagram of the adsorption process of the functionalized nanofibers in the present invention.

[0025] Figure 7 These are the SEM and mapping images of the functionalized nanofibers before adsorption in the present invention.

[0026] Figure 8 These are the SEM and mapping images of the functionalized nanofibers after adsorption in the present invention. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0028] See also Figures 1 to 8 The present invention provides a method for removing fluoride ions from water, the method for removing fluoride ions from water comprising the following steps:

[0029] S1: adding alkaline solution or acid solution to adjust the pH value of the fluoride ion-containing water body;

[0030] S2: adding iron ions and aluminum ions;

[0031] S3: adding functionalized nanofibers to remove fluoride ions indirectly from fluoridated water;

[0032] S4: soaking the functionalized nanofibers after adsorption saturation in a 1-4 mol / L sulfuric acid aqueous solution for desorption;

[0033] S5: Soaking in a 0.5-2 mol / L sodium hydroxide aqueous solution to achieve regeneration of the functionalized nanofibers.

[0034] In this embodiment, the iron ions and the aluminum ions are added to form a stable complex with the fluoride ions to change the chemical properties and behavior of the fluoride ions, thereby affecting their migration behavior in chemical reactions and the environment; the functionalized nanofibers adsorb the fluoride-containing metal ion complexes in the water body, thereby achieving the removal of fluoride ions in the fluoride-containing water body; and the functionalized nanofibers can be recycled through desorption and regeneration.

[0035] Wherein, in step S1, the pH value is in the range of 1.0 to 7.0. Specifically, when an acid or alkaline solution is added to adjust the pH value of the water body, the reduction in the concentration of fluoride ions under acidic conditions will affect their migration behavior in the electric field; because in the electric field, the migration speed and direction of fluoride ions are affected by their concentration and charge; if the concentration of fluoride ions decreases, its migration speed may slow down. Under alkaline conditions, the increased fluoride ion concentration may accelerate its migration speed, but it may also increase the interference of other ions, such as OH- competing with fluoride ions for migration.

[0036] Wherein, in step S2, the iron ion source is one or a mixture of ferric sulfate, ferric chloride or ferric nitrate.

[0037] Wherein, in step S2, the aluminum ion source is one or a mixture of aluminum chloride hexahydrate, aluminum sulfate or aluminum nitrate.

[0038] Wherein, in step S2, the fluoride ions interact with the iron ions to form a hexafluoroferrate ion complex, and the hexafluoroferrate ion complex can be adsorbed by the functionalized nanofibers.

[0039] Wherein, in step S2, the fluoride ions interact with the aluminum ions to form a hexafluoroaluminate ion complex, and the hexafluoroaluminate ion complex can be adsorbed by the functionalized nanofibers.

[0040] Wherein, in step S3, the functionalized nanofibers adsorb the hexafluoroferrate ions or the hexafluoroaluminate ions to indirectly remove fluoride ions from the fluoride-containing water body.

[0041] Embodiment 1:

[0042] Effect of pH value in water on fluoride ion adsorption performance: Prepare some 500 mg / L fluoride ion solution, add quantitative fluoride ions and iron ions to the water, where the molar ratio of fluoride ions to iron ions is 6:1, ultrasonicate for 20 minutes, control the pH value in the water to change between 0 and 7, measure 20 mL of fluorine-containing complex water at different pH values, weigh 20 mg of functionalized nanofibers, statically adsorb for 24 hours at room temperature, design 3 groups of parallel experiments, and determine the maximum adsorption capacity of functionalized nanofibers for fluoride ion adsorption equilibrium at different pH values. Figure 2 .

[0043] Embodiment 2:

[0044] Adsorption isotherms of functionalized nanofibers for fluoride-containing water: prepare fluoride ion solutions of different concentrations, add quantitative fluoride ions and iron ions to water, where the molar ratio of fluoride ions to iron ions is 6:1, ultrasonicate for 20 minutes, and control the pH value of the water to be 5.0; measure 20 mL of fluorine-containing complex water at different pH values, weigh 20 mg of functionalized nanofibers, and statically adsorb for 24 hours at room temperature. Design 3 sets of parallel experiments, and determine the maximum adsorption capacity of functionalized nanofibers for fluoride ions at different fluoride ion concentrations. Figure 3 .

[0045] Embodiment three:

[0046] Functionalized nanofibers adsorb fluoride ion water kinetics: Prepare 200mL of 500mg / L fluoride ion solution, add quantitative fluoride ions and iron ions to the water, where the molar ratio of fluoride ions to iron ions is 6:1, ultrasonicate for 20 minutes, and control the pH value of the water to be 5.0; weigh 200mg of functionalized nanofibers, measure 200mL of fluoride-containing water, and perform static adsorption at room temperature. Design 3 parallel experiments. Determine the adsorption capacity of functionalized nanofibers for fluoride ions at different adsorption times. The kinetics of fluoride ion adsorption by functionalized nanofibers is shown in Figure 4 .

[0047] Embodiment 4:

[0048] The fluoride ion adsorption and regeneration performance of functionalized nanofibers: Prepare a 500 mg / L fluoride ion solution, add a certain amount of fluoride ions and iron ions to the water, where the molar ratio of fluoride ions to iron ions is 6:1, perform ultrasonic treatment for 20 minutes, and control the pH value in the water to be 5.0; measure 20 mL of the 500 mg / L fluoride ion solution, weigh 20 mg of functionalized nanofibers, and perform static adsorption for 5 hours at room temperature to determine the maximum adsorption capacity; filter out the functionalized nanofibers, and desorb them by soaking them in a 3 mol / L sulfuric acid aqueous solution for 1 hour. After filtering, soak them in a 1 mol / L sodium hydroxide aqueous solution for 30 minutes to fully activate them, and then wash them to neutrality; repeat the above operation cycle of adsorption / desorption / activation to determine the maximum adsorption capacity of the functionalized nanofibers for fluoride ions at each cycle number. Figure 5 .

[0049] Embodiment five:

[0050] The adsorption process of hexafluoroferrate ions on functionalized nanofibers is shown in Figure 6 The fluoride ions and iron ions form a regular octahedral complex, and the functionalized nanofiber adsorption sites interact with the hexafluoroferrate ions to achieve the removal of fluoride ions in fluoride-containing water. The SEM and Mapping of the functionalized nanofibers before and after the adsorption of hexafluoroferrate ions are shown in Figure 2. Figure 7 and Figure 8By comparing the SEM images before and after adsorption, it can be observed that the surface of the functionalized nanofibers is rougher after adsorption than before adsorption, and the mapping image after adsorption shows that the signals of Fe and F are evenly distributed on the surface of the functionalized nanofibers.

[0051] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for removing fluoride ions from water, characterized in that: The steps include: S1: adding alkaline solution or acid solution to adjust the pH value of the fluoride ion-containing water body; S2: adding iron ions and aluminum ions; S3: adding functionalized nanofibers to indirectly remove fluoride ions from fluoridated water; S4: soaking the functionalized nanofibers after adsorption saturation in a 1-4 mol / L sulfuric acid aqueous solution for desorption; S5: Soaking in a 0.5-2 mol / L sodium hydroxide aqueous solution to achieve regeneration of the functionalized nanofibers.

2. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S1, the pH value is in the range of 1.0 to 7.

0.

3. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S2, the iron ion source is one or a mixture of ferric sulfate, ferric chloride or ferric nitrate.

4. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S2, the aluminum ion source is one or a mixture of aluminum chloride hexahydrate, aluminum sulfate or aluminum nitrate.

5. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S2, the fluoride ions interact with the iron ions to form a hexafluoroferrate ion complex.

6. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S2, the fluoride ions interact with the aluminum ions to form a hexafluoroaluminate ion complex.

7. The method for removing fluoride ions from water according to claim 1, characterized in that: In step S3, the functionalized nanofibers adsorb the hexafluoroferrate ions or the hexafluoroaluminate ions to indirectly remove fluoride ions from the fluoride-containing water.

Images