Gel resin-based nanophosphate composite material, preparation method and application

Abstract

The application discloses a gel resin-based nanophosphate composite material, a preparation method and application. The main structural components of the composite material include a gel-type strong alkaline anion resin and tetravalent metal phosphate nanoparticles embedded in the resin. In the preparation, the gel-type strong alkaline anion resin is first placed in an acid solution to react to obtain a pretreated resin, then a tetravalent metal salt is dissolved in an alcohol solution to stir uniformly to obtain a material liquid, then the resin is added to the material liquid, and finally the material liquid is placed in a phosphoric acid solution to stir and react. The composite material has Lewis and acidic sites at the same time, can realize efficient and selective removal of fluoride in water under neutral and alkaline conditions, and the adsorption capacity of fluoride ions can reach more than 4 mg / g. Moreover, the desorption efficiency is high, and the composite material can be recycled and regenerated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of phosphate composite materials, and particularly relates to a gel resin-based nanophosphate composite material, a preparation method and application. BACKGROUND

[0002] Fluorine is an essential element for human body, and appropriate intake can improve the strength of teeth, prevent dental caries, and is beneficial to the formation and strength improvement of bones; but excessive intake of fluorine will cause fluorine poisoning in human body, leading to fluorosis, fluorosis, and other diseases. Fluorine pollution in natural water is mainly in inorganic state, mainly from fluorine release of fluorine-containing minerals such as cryolite (Na3[AlF6]), fluorite (CaF2), fluorapatite (Ca 10 (CaF2), fluorapatite (Ca

[0003] Adsorption method has the advantages of low cost, easy operation, stable effect, and wide application prospect in the field of deep treatment of fluorides in water. Non-metallic adsorbents such as carbon-based materials such as activated carbon and biomass materials such as cellulose have large specific surface area and rich pore structure, and can realize the enrichment and separation of fluorides through non-specific adsorption such as van der Waals force or hydrogen bond, but are easily interfered by a large amount of coexisting anions such as chlorides and sulfates in water, and are also easily desorbed due to water quality fluctuations such as pH, temperature and ionic strength. Lewis acid type adsorption materials represented by Zr(IV), Ti(IV), Sn(IV) and other tetravalent metal (hydrogen) oxide nanoparticles can form stable inner coordination compounds with fluorine ions through Lewis hard acid-hard base interaction, so as to realize high selectivity adsorption of fluorides. However, since the radius of hydroxyl ions and fluoride ions is close, the charge number is the same, and the coordination property is similar, the deep defluorination performance of nanocomposites is significantly inhibited by hydroxyl ions, and the treatment effect is poor in alkaline conditions (Environ. Sci. Technol. 2013, 47, 16, 9347-9354).

[0004] Tetravalent metal phosphate has rich acid sites, which is expected to overcome the adverse effects of hydroxyl ions; but tetravalent metal phosphate has strong stability, and the Lewis acid sites on the surface of the material are easily covered by phosphate groups, thereby losing the selective purification ability of fluorides.

[0005] Therefore, there is an urgent need to develop a new type of environmental functional material suitable for neutral or alkaline conditions with high efficient defluorination performance. SUMMARY

[0006] Technical problems solved by the application: The technical problems solved by the application are to provide a composite material with high fluorine removal efficiency under neutral or alkaline conditions and a preparation process thereof.

[0007] Technical scheme: The gel resin-based nanophosphate composite material of the application mainly comprises a gel-type strong alkaline anion resin and tetravalent metal phosphate nanoparticles embedded in the resin, and the nanoparticle loading amount is >5wt%. The skeleton of the gel-type strong alkaline anion resin is polystyrene or polyacrylate, and the functional group is quaternary ammonium or pyridine.

[0008] The application is based on tetravalent metal phosphate with abundant acid sites, and the tetravalent metal phosphate is loaded on a gel-type strong alkaline anion resin. During the loading process, the zirconium phosphate has both phosphate groups and hydroxyl groups, so that the prepared composite material has both Lewis and acid sites. Under the condition that the phosphate group provides an acidic environment, the hydroxyl group and fluorine perform ligand exchange to realize selective adsorption of fluorides, and then realize high-efficiency selective removal of fluorides in water under neutral and alkaline conditions.

[0009] Further, the tetravalent metal phosphate nanoparticles used in the composite material can be zirconium phosphate, titanium phosphate or tin phosphate, and the average particle size is <5nm.

[0010] The method for preparing the composite material comprises the following steps:

[0011] (1) reacting the gel-type strong alkaline anion resin in an acid solution for 2-6h to obtain a pretreated resin;

[0012] (2) dissolving tetravalent metal salt in an alcohol solution and stirring uniformly to obtain a feed solution;

[0013] (3) adding the pretreated resin in step (1) to the feed solution in step (2), stirring and reacting for 4-12h, and then filtering out the resin;

[0014] (4) placing the resin filtered out in step (3) in a phosphoric acid solution, stirring and reacting for 10-24h, and then taking out, washing, drying and obtaining the composite material.

[0015] Further, in step (1) of the preparation method, the acid solution can be hydrochloric acid or sulfuric acid with a mass fraction of 2-5%.

[0016] Further, in step (1) of the preparation method, the solid-liquid ratio of the gel-type resin to the acid solution can be 10-500g / L.

[0017] Further, in step (2) of the preparation method, the alcohol solution can be a methanol or ethanol solution.

[0018] Further, in step (2) of the preparation method, the mass fraction of the tetravalent metal salt in the feed solution can be 5-60%, and the mass ratio of the resin to the tetravalent metal salt can be 1:(1-20).

[0019] Further, in step (3) of the preparation method, the mass fraction of the phosphoric acid solution can be 5-30%, and the solid-liquid ratio of the resin to the phosphoric acid solution can be 10-100 g / L.

[0020] The gel resin-based nanophosphate composite material of the present application is applied to the selective removal of water fluorides under neutral and alkaline conditions.

[0021] Advantages: Compared with the prior art, the significant advantages of the present application are that the composite material simultaneously has Lewis and acid sites, and can achieve efficient and selective removal of fluorides in water under neutral and alkaline conditions, and the adsorption capacity of fluorine ions can reach more than 4 mg / g; and the desorption efficiency is high, and the composite material can be recycled and reused. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 An optical photograph of the gel resin-based nanophosphate zirconium composite material prepared in Example 1 of the present application;

[0023] Figure 2 A transmission electron microscope (TEM) photograph of the gel resin-based nanophosphate zirconium composite material prepared in Example 1 of the present application;

[0024] Figure 3 A defluorination effect diagram of the gel resin-based nanophosphate zirconium composite material prepared in Example 1 of the present application under different pH conditions;

[0025] Figure 4 An adsorption-regeneration cycle effect diagram of the gel resin-based nanophosphate zirconium composite material prepared in Example 1 of the present application;

[0026] Figure 5 A column adsorption effect diagram of the gel resin-based nanophosphate zirconium composite material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be further described in detail below in combination with the drawings and examples.

[0028] It should be noted that the raw materials used in the present application can be purchased from the market.

[0029] Example 1

[0030] The gel resin-based nano-zirconium phosphate composite material structure of this embodiment is a gel type strong basic anion resin with polystyrene as the skeleton and quaternary ammonium group as the functional group, and zirconium phosphate loaded in the resin, with a loading amount of 8.5%.

[0031] The composite material of this embodiment is prepared by the following steps:

[0032] (1) 5 g of the gel type strong basic anion resin is washed and dried, and then put into a 2% hydrochloric acid solution, with a solid-liquid ratio of the gel type strong basic resin to the acid solution of 100 g / L. After stirring for 4 h, it is dried for standby use;

[0033] (2) 40 g of zirconium chloride is dissolved in methanol to prepare a zirconium alcohol solution with a mass fraction of 10%;

[0034] (3) The gel type strong basic resin pretreated in step (1) is added to the solution prepared in step (2), and stirred for 8 h, and then the resin is filtered out;

[0035] (4) The resin filtered out in step (3) is slowly added into a 5% phosphoric acid solution, with a solid-liquid ratio of the gel type strong basic resin to the phosphoric acid solution of 50 g / L. After stirring at room temperature for 12 h, it is fully reacted;

[0036] (5) The resin in step (4) is taken out, washed with pure water until neutral, and then dried to prepare the gel resin-based nano-zirconium phosphate composite material.

[0037] Performance detection-structure characterization

[0038] The optical photograph of the composite material prepared in this embodiment is as shown in Figure 1 , and the structure of the composite material is characterized, and the obtained results are as shown in Figure 2 . It can be known from Figure 1 and Figure 2 that the composite material is a gel wrapping type, and the nano-particle zirconium phosphate is embedded in the resin particles. The diameter of the gel resin-based nano-zirconium phosphate composite material is 0.45-0.60 mm, the nano-particle size is <5 nm, and the zirconium loading amount is 8.5% measured by an inductively coupled plasma emission spectrometer.

[0039] Performance detection-fluoride ion adsorption

[0040] 0.05 g of the composite material of the present application is added into 100 mL of a solution with a fluoride ion concentration of 10 mg / L and a chloride ion concentration of 1 g / L and with pH values of 7, 8, 9 and 10 respectively to perform a fluoride ion adsorption test, and the obtained results are as shown in Figure 3 . It can be known from the figure that the adsorption amount of the composite material of the present application to the fluoride ion can reach 5 mg / g, 4.8 mg / g, 4.4 mg / g and 4 mg / g respectively.

[0041] Performance Testing -- Adsorption and Regeneration Cycle

[0042] This invention conducted eight consecutive cycles of "adsorption-desorption-regeneration" experiments, and the results are as follows: Figure 4 As shown, the fluoride ions adsorbed by the composite material of the present invention can be effectively desorbed by a mixed solution of 1wt% NaOH and 2wt% NaCl, with a desorption rate of over 95% in each cycle. Furthermore, the adsorption capacity of the composite material of the present invention did not show a significant decrease after 8 cycles of "adsorption-desorption-regeneration", indicating that its fluoride removal capacity can be effectively restored by sequential treatment with NaOH-HCl solution.

[0043] Performance Testing -- Column Adsorption

[0044] This invention simulates actual wastewater through column adsorption experiments. For example... Figure 5 As shown, the water treatment capacity of the composite material of the present invention is ~280 BV, indicating that it has a good defluorination effect under neutral conditions.

[0045] Example 2

[0046] The structure of the gel resin-based nano-zirconium phosphate composite material in this embodiment is a polystyrene-based gel-type strong basic anion exchange resin with quaternary ammonium functional groups and zirconium phosphate loaded within the resin. The loading amount is 8.3%.

[0047] The preparation steps of the composite material in this embodiment are the same as those in Example 1, except that a 2% sulfuric acid solution is used in step (1).

[0048] Performance Testing -- Fluoride Ion Adsorption

[0049] Fluoride ion adsorption tests were conducted by adding 0.05g of the composite material of the present invention to 100mL of solutions with fluoride ion concentration of 10mg / L, chloride ion concentration of 1g / L, and pH values ​​of 7, 8, 9, and 10, respectively. The results showed that the composite material of the present invention could adsorb fluoride ions at concentrations of 5.1mg / g, 4.6mg / g, 4.2mg / g, and 4mg / g, respectively.

[0050] Example 3

[0051] The structure of the gel resin-based nano-zirconium phosphate composite material in this embodiment is a gel-type strong basic anion exchange resin with polystyrene as the backbone and pyridyl functional groups, and zirconium phosphate loaded in the resin, with a loading of 9.2%.

[0052] The composite material steps in this embodiment are the same as in Embodiment 1.

[0053] Performance Testing -- Fluoride Ion Adsorption

[0054] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the adsorption amount of fluorine ions of the composite material of the application can reach 5.5 mg / g, 4.9 mg / g, 4.7 mg / g and 4.4 mg / g respectively.

[0055] Example 4

[0056] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polyacrylate as a skeleton, a gel type strong alkaline anion resin with quaternary ammonium groups as a functional group and zirconium phosphate loaded in the resin, and the loading amount is 8%.

[0057] The composite material of this example has the same steps as those of Example 1.

[0058] Performance test-fluorine ion adsorption

[0059] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the adsorption amount of fluorine ions of the composite material of the application can reach 5.5 mg / g, 4.9 mg / g, 4.7 mg / g and 4.4 mg / g respectively.

[0060] Example 5

[0061] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polyacrylate as a skeleton, a gel type strong alkaline anion resin with pyridine groups as a functional group and zirconium phosphate loaded in the resin, and the loading amount is 8.2%.

[0062] The composite material of this example has the same steps as those of Example 1.

[0063] Performance test-fluorine ion adsorption

[0064] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the adsorption amount of fluorine ions of the composite material of the application can reach 5.5 mg / g, 4.9 mg / g, 4.7 mg / g and 4.4 mg / g respectively.

[0065] Example 6

[0066] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polyacrylate as a skeleton, a gel type strong alkaline anion resin with pyridine groups as a functional group and zirconium phosphate loaded in the resin, and the loading amount is 8%.

[0067] The composite material of this example has the same basic steps as example 1, except that in step (2), 40 g of zirconium chloride dissolved in methanol is added to prepare a zirconium alcohol solution with a mass fraction of 20%.

[0068] Performance test-fluoride ion adsorption

[0069] The fluoride ion adsorption test was carried out by adding 0.05 g of the composite material of the application to 100 mL of a solution with a fluoride ion concentration of 10 mg / L, a chloride ion concentration of 1 g / L, and a pH of 7, 8, 9, and 10, respectively. The results show that the adsorption capacity of the composite material of the application for fluoride ions can reach 5.5 mg / g, 5.1 mg / g, 4.7 mg / g, and 4.5 mg / g, respectively.

[0070] Example 7

[0071] The gel resin-based nano-zirconium phosphate composite material of this example has a structure of polystyrene as a skeleton, a gel-type strong alkaline anion resin with quaternary ammonium groups as a functional group, and zirconium phosphate loaded in the resin, with a loading amount of 9.1%.

[0072] The basic steps of the composite material of this example are the same as those of example 1, except that in step (2), 28 g of titanium chloride is dissolved in methanol, stirred uniformly, and a titanium alcohol solution with a mass fraction of 10% is prepared.

[0073] Performance test-fluoride ion adsorption

[0074] The fluoride ion adsorption test was carried out by adding 0.05 g of the composite material of the application to 100 mL of a solution with a fluoride ion concentration of 10 mg / L, a chloride ion concentration of 1 g / L, and a pH of 7, 8, 9, and 10, respectively. The results show that the adsorption capacity of the composite material of the application for fluoride ions can reach 5.6 mg / g, 5.3 mg / g, 5 mg / g, and 4.8 mg / g, respectively.

[0075] Example 8

[0076] The gel resin-based nano-zirconium phosphate composite material of this example has a structure of polystyrene as a skeleton, a gel-type strong alkaline anion resin with quaternary ammonium groups as a functional group, and zirconium phosphate loaded in the resin, with a loading amount of 9.1%.

[0077] The basic steps of the composite material of this example are the same as those of example 1, except that in step (2), 35 g of tin chloride is dissolved in methanol, stirred uniformly, and a tin alcohol solution with a mass fraction of 10% is prepared.

[0078] Performance test-fluoride ion adsorption

[0079] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the fluorine ion adsorption capacity of the composite material of the application can reach 5.3 mg / g, 5 mg / g, 4.9 mg / g and 4.4 mg / g respectively.

[0080] Example 9

[0081] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polystyrene as a skeleton, a gel type strong alkaline anion resin with quaternary ammonium groups as functional groups and zirconium phosphate loaded in the resin, and the loading amount is 8%.

[0082] The basic steps of the composite material of this example are the same as those of Example 1, except that in step (1), the concentration of the hydrochloric acid solution used is 5% and stirring is performed for 2 h.

[0083] Performance test-fluorine ion adsorption

[0084] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the fluorine ion adsorption capacity of the composite material of the application can reach 5 mg / g, 4.7 mg / g, 4.5 mg / g and 4.1 mg / g respectively.

[0085] Example 10

[0086] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polystyrene as a skeleton, a gel type strong alkaline anion resin with quaternary ammonium groups as functional groups and zirconium phosphate loaded in the resin, and the loading amount is 10%.

[0087] The basic steps of the composite material of this example are the same as those of Example 1, except that in step (2), 40 g of zirconium chloride is dissolved in methanol to prepare a zirconium alcohol solution with a mass fraction of 30%.

[0088] Performance test-fluorine ion adsorption

[0089] The fluorine ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluorine ion concentration of 10 mg / L, a chlorine ion concentration of 1 g / L and pH values of 7, 8, 9 and 10 respectively shows that the fluorine ion adsorption capacity of the composite material of the application can reach 5.5 mg / g, 5.3 mg / g, 4.9 mg / g and 4.4 mg / g respectively.

[0090] Example 11

[0091] The gel resin-based nano zirconium phosphate composite material structure of this embodiment is a gel type strong alkaline anion resin with polystyrene as the skeleton and quaternary ammonium group as the functional group, and zirconium phosphate loaded in the resin, with a loading amount of 11%.

[0092] The basic steps of the composite material of this embodiment are the same as those of embodiment 1, except that in step (4), the resin filtered in step (3) is slowly added into a 15% phosphoric acid solution, the solid-liquid ratio of the gel type strong alkaline resin to the phosphoric acid solution is 80 g / L, and the reaction is fully stirred at room temperature for 24 h.

[0093] Performance detection-fluoride ion adsorption

[0094] It can be known from the fluoride ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluoride ion concentration of 10 mg / L, a chloride ion concentration of 1 g / L and a pH of 7, 8, 9 and 10 respectively that the adsorption amount of the composite material of the application to fluoride ions can reach 5.6 mg / g, 5.3 mg / g, 5 mg / g and 4.7 mg / g respectively.

[0095] Comparative example 1

[0096] The basic steps are the same as those of embodiment 1, except that the resin is a sulfonic acid group strong acid cation resin.

[0097] Performance detection-fluoride ion adsorption

[0098] It can be known from the fluoride ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluoride ion concentration of 10 mg / L, a chloride ion concentration of 1 g / L and a pH of 7, 8, 9 and 10 respectively that the adsorption amount of the composite material of the application to fluoride ions can reach 0.1 mg / g, 0.08 mg / g, 0.05 mg / g and 0.03 mg / g respectively.

[0099] Comparative example 2

[0100] The basic steps are the same as those of embodiment 1, except that the resin is a quaternary ammonium group macroporous strong alkaline anion resin.

[0101] Performance detection-fluoride ion adsorption

[0102] It can be known from the fluoride ion adsorption test of 0.05 g of the composite material of the application in 100 mL of a solution with a fluoride ion concentration of 10 mg / L, a chloride ion concentration of 1 g / L and a pH of 7, 8, 9 and 10 respectively that the adsorption amount of the composite material of the application to fluoride ions can reach 2 mg / g, 1.7 mg / g, 1 mg / g and 0.4 mg / g respectively.

[0103] It can be known from comparative example 1 and comparative example 2 that the composite material of the application can be loaded with a large amount of zirconium phosphate by loading zirconium phosphate on a strong acid cation resin or a strong alkaline anion resin, and the composite material of the application has a large specific surface area and a large number of active sites, so that the composite material of the application has a large adsorption capacity for fluoride ions. The tetravalent metal phosphate of acid site is loaded on the gel type strong basic anion resin, and the tetravalent metal phosphate without hydroxyl group is endowed with both phosphoric acid group and hydroxyl group through the gel type strong basic anion resin, so that the prepared composite material has both Lewis and acid sites. Under the condition that the phosphoric acid group provides an acidic environment, the hydroxyl group and fluorine are promoted to exchange ligands to realize selective adsorption of fluoride, and then realize high-efficiency selective removal of fluoride in water under neutral and alkaline conditions.

[0104] Example 12

[0105] The gel resin-based nano zirconium phosphate composite material of this example has a structure of polystyrene as a skeleton, a functional group of quaternary ammonium group of the gel type strong basic anion resin, and zirconium phosphate loaded in the resin, and the loading amount is 6.2%.

[0106] The composite material of this example is prepared by the following steps:

[0107] (1) 5 g of the gel type strong basic anion resin is washed and dried, and then is put into a 2% hydrochloric acid solution, the solid-liquid ratio of the gel type strong basic resin to the acid solution is 10 g / L, after stirring for 6 h, it is dried for standby;

[0108] (2) 5 g of zirconium chloride is dissolved in methanol to prepare a zirconium alcohol solution with a mass fraction of 60%;

[0109] (3) The gel type strong basic resin pretreated in step (1) is added to the solution prepared in step (2), and after stirring for 4 h, the resin is filtered out;

[0110] (4) The resin filtered out in step (3) is slowly added into a 5% phosphoric acid solution, the solid-liquid ratio of the gel type strong basic resin to the phosphoric acid solution is 10 g / L, and after stirring at room temperature for 20 h, the reaction is completed;

[0111] (5) The resin in step (4) is taken out, washed with pure water until neutral, and then dried to prepare the gel resin-based nano zirconium phosphate composite material.

[0112] The adsorption test of fluoride ions is carried out by adding 0.05 g of the composite material of the application to 100 mL of a solution with a fluoride ion concentration of 10 mg / L and a chloride ion concentration of 1 g / L and a pH of 7, 8, 9 and 10 respectively, and it is found that the adsorption amount of fluoride ions of the composite material of the application can reach 4.9 mg / g, 4.7 mg / g, 4.2 mg / g and 4 mg / g respectively.

[0113] Example 13

[0114] The gel resin-based nano-zirconium phosphate composite material structure of this embodiment is a gel type strong alkaline anion resin with polystyrene as a skeleton and quaternary ammonium groups as functional groups, and zirconium phosphate loaded in the resin, with a loading amount of 10.1%.

[0115] The composite material of this embodiment is prepared by the following steps:

[0116] (1) 5 g of the gel type strong alkaline anion resin is washed and dried, and then is put into a 2% hydrochloric acid solution, with a solid-liquid ratio of the gel type strong alkaline resin to the acid solution being 500 g / L. After stirring for 6 h, the gel type strong alkaline resin is dried for standby use;

[0117] (2) 100 g of zirconium chloride is dissolved in ethanol to prepare a zirconium alcohol solution with a mass fraction of 5%;

[0118] (3) The gel type strong alkaline resin pretreated in step (1) is added to the solution prepared in step (2), and the resin is filtered out after stirring for 12 h;

[0119] (4) The resin filtered out in step (3) is slowly added to a 30% phosphoric acid solution, with a solid-liquid ratio of the gel type strong alkaline resin to the phosphoric acid solution being 100 g / L. After stirring at room temperature for 10 h, the resin is washed with pure water until neutral, and then is dried to prepare the gel resin-based nano-zirconium phosphate composite material.

[0120] (5) The resin in step (4) is taken out, washed with pure water until neutral, and then dried to prepare the gel resin-based nano-zirconium phosphate composite material.

[0121] The fluorine ion adsorption test is carried out by adding 0.05 g of the composite material of the present application to 100 mL of a solution with a fluorine ion concentration of 10 mg / L and a chloride ion concentration of 1 g / L and with pH values of 7, 8, 9 and 10, respectively. The results show that the adsorption amount of the composite material of the present application to fluorine ions can reach 5.6 mg / g, 5.2 mg / g, 5 mg / g and 4.7 mg / g, respectively.

Claims

1. A gel resin based nanophosphate composite material characterized by: The main structural components of the composite material include a gel type strong alkaline anion resin and embedded tetra-valent metal phosphate nanoparticles in the resin, the nanoparticle loading is >5wt%, the skeleton of the gel type strong alkaline anion resin is polystyrene or polyacrylate, and the functional group is quaternary ammonium group or pyridine group; the tetra-valent metal phosphate nanoparticles are zirconium phosphate, titanium phosphate or tin phosphate, and the average size of the particles is <5nm; The gel resin based nanoparticle phosphate composite material is prepared by the following steps: (1) reacting the gel type strong alkaline anion resin in an acid solution for 2-6h to obtain a pretreated resin; (2) dissolving the tetra-valent metal salt in an alcohol solution and stirring to obtain a feed solution; (3) adding the pretreated resin of step (1) to the feed solution of step (2) and stirring for 4-12h, then filtering out the resin; (4) placing the filtered resin of step (3) in a phosphoric acid solution, stirring for 10-24h, and then taking out, washing, drying to obtain the composite material.

2. The gel resin based nanophosphate composite material according to claim 1, characterized by: In step (1), the acid solution is 2-5% hydrochloric acid or sulfuric acid by mass fraction.

3. The gel resin based nanophosphate composite material according to claim 1, wherein: In step (1), the solid-liquid ratio of the gel type strong alkaline anion resin to the acid solution is 10-500g / L.

4. The gel resin based nanophosphate composite material of claim 1, wherein: In step (2), the alcohol solution is a methanol or ethanol solution.

5. The gel resin based nanophosphate composite material according to claim 1, wherein: In step (2), the mass fraction of the tetra-valent metal salt in the feed solution is 5-60%, and the mass ratio of the gel type strong alkaline anion resin to the tetra-valent metal salt is 1:(1-20).

6. The gel resin based nanophosphate composite material according to claim 1, wherein: In step (3), the mass fraction of the phosphoric acid solution is 5-30%, and the solid-liquid ratio of the gel type strong alkaline anion resin to the phosphoric acid solution is 10-100g / L.

7. The gel resin based nanoparticle phosphate composite material of claim 1 is applied to the selective removal of fluoride in water under neutral or alkaline conditions.

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