A polymer-supported X-Al type layered double hydroxide adsorbent and its preparation method

Abstract

This invention provides a polymer-supported X-Al type layered double hydroxide adsorbent and its preparation method, belonging to the field of adsorption material technology. The preparation method of this invention uses ketone-based polymer materials as carriers and layered double hydroxides as loading substances, achieving in-situ synthesis of layered double hydroxides within the polymer material. Furthermore, this process integrates adsorption and granulation, avoiding environmental pollution problems caused by adhesives used in traditional adsorbent granulation processes, simplifying the process flow, and providing valuable reference for practical production.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a polymer-supported X-Al type layered double hydroxide adsorbent and its preparation method. Background Technology

[0002] Layered double hydroxides (LDHs) consist of exchangeable anions and metal hydroxide layers, and their chemical formula is [M]. 2 + 1-x M 3+ x (OH)2] x+ [A n- ] x / y ·yH2O], where M 2+ It is a divalent cation, M 3+ It is a trivalent cation, A n- It is an interlayer anion, x is M 3+ / (M 2+ +M 3+ The molar ratio of M, the layer charge depends on M 2+ / M 3+ The ratio of LDH to its interlayer structure is significant. LDH's layered structure features a large specific surface area, high porosity, interchangeable cations within the layers, and migratable anions between the layers. In aqueous solution, anions between LDH layers can exchange with other ions, and metal cations in the layers can be replaced by metal cations with the same structure or similar ionic radii. Therefore, LDH is often used as an adsorbent for heavy metal wastewater. However, LDH is prone to aggregation during the reaction process, affecting adsorption sites. Furthermore, directly applying powdered adsorbents to heavy metal wastewater results in poor stability and difficulty in recycling, leading to low industrial application rates. Therefore, granulation of powdered LDH adsorbents becomes highly meaningful.

[0003] Currently, commonly used LDH materials mainly include MgAl, MgFe, NiAl, FeAl, and LiAl, and their preparation methods are mainly hydrothermal and coprecipitation methods. The coprecipitation method involves simultaneously adding a metal solution and an alkaline solution, controlling the dropping rate of the alkaline solution to adjust the pH of the mixed solution. At a certain pH value, the metal salt undergoes a coprecipitation reaction and accumulates within the polymeric ketone material, forming a granular adsorbent. The hydrothermal method is mainly used to synthesize materials with high crystallinity and purity. A polymeric ketone material, a metal ion solution, and an alkaline solution are added to a high-pressure reactor, forming a supersaturated solution. Hydrothermal treatment is then performed to obtain a novel LDH-loaded adsorbent.

[0004] Compared with traditional LDH, LDH can be directly loaded into polymeric ketone materials through in-situ synthesis, resulting in uniform particles with stable mechanical properties and low solubility. It can be directly packed into columns to adsorb the feed solution to be treated, making it possible for large-scale industrial applications.

[0005] Therefore, it is of great significance to study a polymer material loaded with X-Al type layered double hydroxide adsorbent that has good stability, can be recycled, and avoids the need for re-granulation after adsorbent synthesis. Summary of the Invention

[0006] The purpose of this invention is to provide a polymer-supported X-Al type layered double hydroxide adsorbent and its preparation method, in order to solve the technical problems of poor stability, non-recyclability, and environmental pollution caused by the use of adhesives in the granulation process in the prior art.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a polymer-supported X-Al type layered double hydroxide adsorbent, wherein the layered double hydroxide adsorbent uses a ketone-based polymer as a carrier and a layered double hydroxide as a loading medium.

[0009] Furthermore, the mass ratio of the layered double hydroxide to the ketone polymer material is 0.2 to 0.8:1.

[0010] Furthermore, the ketone-based polymeric material includes one or more of polyetheretherketone, acetone, and acetophenone;

[0011] The layered double hydroxide includes one or more of lithium aluminum layered double hydroxide, magnesium aluminum layered double hydroxide, calcium aluminum layered double hydroxide, and iron aluminum layered double hydroxide.

[0012] This invention provides a method for preparing an X-Al type layered double hydroxide adsorbent supported on a polymer material, comprising the following steps:

[0013] (1) The ketone polymer material is mixed with concentrated sulfuric acid and subjected to sulfonation reaction to obtain sulfonated ketone polymer;

[0014] (2) The sulfonated ketone polymer and the X-Al mixed solution were mixed and pretreated to obtain a sulfonated ketone polymer solution loaded with X-Al mixed solution;

[0015] (3) The sulfonated ketone polymer solution loaded with X-Al mixed solution was subjected to a co-precipitation reaction with concentrated ammonia to obtain a polymer material loaded with X-Al type layered double hydroxide adsorbent.

[0016] Furthermore, in step (1), the mass-to-volume ratio of the ketone polymer to concentrated sulfuric acid is 1g:5-10mL;

[0017] The sulfonation reaction is carried out at a temperature of 40–95°C for 1–12 hours.

[0018] The sulfonated ketone polymer has a pH of 6-7 and an electrical conductivity of 0-100 μS.

[0019] Furthermore, in step (2), the Al in the X-Al mixed solution 3+ The concentration is 0.1–5 mol / L, X n+ The concentration is 0.05–8 mol / L;

[0020] Among them, X n+ For Li + Mg 2+ Ca 2+ or Fe 3+ .

[0021] Furthermore, in step (2), the volume ratio of the sulfonated ketone polymer and the X-Al mixed solution is 1:2 to 10.

[0022] Furthermore, in step (2), the temperature of the mixing pretreatment is 25-60°C and the time is 1-10h.

[0023] Furthermore, in step (3), the volume ratio of the sulfonated ketone polymer solution loaded with X-Al mixed solution to concentrated ammonia is 1:5 to 10, and the concentration of concentrated ammonia is 1 to 10 mol / L.

[0024] Furthermore, in step (3), the temperature of the coprecipitation reaction is 70-85°C and the time is 2-12 hours.

[0025] The beneficial effects of this invention are:

[0026] (1) This invention uses ketone polymer materials as carriers to realize in-situ generation technology that integrates powder synthesis and granulation. The process is simple and conducive to industrial production.

[0027] (2) Unlike other polymer materials, the ketone polymer material used in this invention has extremely strong hydrophilicity. Using the ketone polymer material as a carrier, the synthesized adsorbent has extremely strong hydrophilicity, and the mass transfer problem of the adsorbent in brine is solved.

[0028] (3) Using ketone polymer materials as carriers, the surface of the spheres formed has a porous sponge-like structure. The adsorbent is in contact with the liquid, which can ensure sufficient adsorption sites, thereby improving the adsorption efficiency per unit time.

[0029] (4) Using ketone polymer materials as carriers, which have good mechanical properties and high strength, can ensure that the adsorbent loss rate is low during the adsorption process. Attached Figure Description

[0030] Figure 1 The image shows the XRD pattern of the polymer material supported on the Li-Al type layered double hydroxide adsorbent in Example 1.

[0031] Figure 2 This is a scanning electron microscope image of the polymer material supported on the Li-Al type layered double hydroxide adsorbent in Example 1.

[0032] Figure 3 This is a graph showing the adsorption capacity test data of the polymer material supported on the Li-Al type layered double hydroxide adsorbent prepared in Example 1 after different cycles. Detailed Implementation

[0033] This invention provides a polymer-supported X-Al type layered double hydroxide adsorbent, wherein the layered double hydroxide adsorbent uses a ketone-based polymer as a carrier and a layered double hydroxide as a loading medium.

[0034] In this invention, the mass ratio of the layered double hydroxide to the ketone polymer is 0.2 to 0.8:1, preferably 0.3 to 0.7:1, and more preferably 0.4 to 0.6:1.

[0035] In this invention, the ketone-based polymeric material includes one or more of polyether ether ketone, acetone and acetophenone, preferably polyether ether ketone and / or acetone, and more preferably polyether ether ketone.

[0036] In this invention, the layered double hydroxide includes one or more of lithium aluminum layered double hydroxide, magnesium aluminum layered double hydroxide, calcium aluminum layered double hydroxide, and iron aluminum layered double hydroxide, preferably one or more of lithium aluminum layered double hydroxide, magnesium aluminum layered double hydroxide, and iron aluminum layered double hydroxide, and more preferably lithium aluminum layered double hydroxide and / or magnesium aluminum layered double hydroxide.

[0037] This invention provides a method for preparing an X-Al type layered double hydroxide adsorbent supported on a polymer material, comprising the following steps:

[0038] (1) The ketone polymer material is mixed with concentrated sulfuric acid and subjected to sulfonation reaction to obtain sulfonated ketone polymer;

[0039] (2) The sulfonated ketone polymer and the X-Al mixed solution were mixed and pretreated to obtain a sulfonated ketone polymer solution loaded with X-Al mixed solution;

[0040] (3) The sulfonated ketone polymer solution loaded with X-Al mixed solution was subjected to a co-precipitation reaction with concentrated ammonia to obtain a polymer material loaded with X-Al type layered double hydroxide adsorbent.

[0041] In this invention, in step (1), the mass-to-volume ratio of the ketone polymer to concentrated sulfuric acid is 1g:5-10mL, preferably 1g:6-9mL, and more preferably 1g:7-8mL;

[0042] The sulfonation reaction is carried out at a temperature of 40–95°C, preferably 45–90°C, and more preferably 50–85°C; the reaction time is 1–12 h, preferably 2–10 h, and more preferably 4–8 h.

[0043] The sulfonated ketone polymer has a pH value of 6-7, preferably 6.2-6.8, and more preferably 6.4-6.7; and an electrical conductivity of 0-100 μS, preferably 10-90 μS, and more preferably 20-80 μS.

[0044] In this invention, in step (2), the Al in the X-Al mixed solution 3+ The concentration is 0.1–5 mol / L, preferably 0.2–4.5 mol / L, and more preferably 1–4 mol / L; wherein X n+ The concentration is 0.05–8 mol / L, preferably 0.1–7.5 mol / L, and more preferably 0.5–7 mol / L;

[0045] Among them, X n+ For Li + Mg 2+ Ca 2+ or Fe 3+ Li is preferred + Mg 2+ or Ca 2+ Li is further preferred. + or Ca 2+ .

[0046] In this invention, in step (2), the volume ratio of the sulfonated ketone polymer and the X-Al mixed solution is 1:2 to 10, preferably 1:3 to 9, and more preferably 1:4 to 8.

[0047] In this invention, in step (2), the temperature of the mixing pretreatment is 25-60°C, preferably 30-55°C, and more preferably 35-50°C; the time is 1-10h, preferably 2-9h, and more preferably 3-8h.

[0048] In this invention, in step (3), the volume ratio of the sulfonated ketone polymer solution loaded with X-Al mixed solution to concentrated ammonia is 1:5 to 10, preferably 1:6 to 9, and more preferably 1:7 to 8; the concentration of the concentrated ammonia is 1 to 10 mol / L, preferably 2 to 9 mol / L, and more preferably 3 to 8 mol / L.

[0049] In this invention, in step (3), the temperature of the coprecipitation reaction is 70-85°C, preferably 73-82°C, and more preferably 75-80°C; the time is 2-12 hours, preferably 3-10 hours, and more preferably 4-8 hours.

[0050] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] (1) Wash the surface of 20g of polyether ether ketone powder with water and dry it at 60°C to obtain ketone polymer material. Then mix it with 100mL of 98% concentrated sulfuric acid and carry out sulfonation reaction at 80°C for 4 hours to obtain sulfonated ketone polymer. Clean the sulfonated ketone polymer until its conductivity is 50uS and its pH value is 6.86.

[0053] (2) Take 50 mL of sulfonated ketone polymer and 400 mL of Li-Al mixed solution (Al 3+ The concentration is 1.5 mol / L, Li + The solution was stirred for 8 hours at a concentration of 0.5 mol / L at a speed of 300 rpm and a temperature of 45℃, and then the solid and liquid were separated by filtration to obtain a sulfonated ketone polymer solution loaded with Li-Al mixed solution.

[0054] (3) The sulfonated ketone polymer solution with a volume ratio of 1:7 loaded Li-Al mixed solution was co-precipitated with concentrated ammonia at 75°C for 4 hours. The concentration of concentrated ammonia used was 5 mol / L. After the reaction, the solution was dried in an oven at 60°C for 4 hours to obtain the polymer material loaded Li-Al type layered double hydroxide adsorbent.

[0055] The XRD pattern of the polymer-supported Li-Al type layered double hydroxide adsorbent prepared in this embodiment is shown below. Figure 1 As shown, the peak comparison reveals that the main component of this layered double hydroxide adsorbent is Li-Al-LDH; the SEM image of this layered double hydroxide adsorbent is shown below. Figure 2 As shown, Li-Al-LDH has a layered structure.

[0056] The layered double hydroxide adsorbent prepared in this embodiment was applied to the brine of a salt lake in Qinghai (Li in the salt lake brine) + The adsorption was performed at a concentration of 0.7 g / L, and the adsorption capacity remained consistently above 4.5 mg for 10 cycles. Figure 3 ).

[0057] Example 2

[0058] (1) Wash the surface of 20g of polyether ether ketone powder with water and dry it at 60°C to obtain ketone polymer material. Then mix it with 120mL of 98% concentrated sulfuric acid and carry out sulfonation reaction at 80°C for 5 hours to obtain sulfonated ketone polymer. Clean the sulfonated ketone polymer until its conductivity is 60uS and its pH value is 6.85.

[0059] (2) Take 50 mL of sulfonated ketone polymer and 450 mL of Mg-Al mixed solution (Al 3+ The concentration is 1.5 mol / L, Mg 2+ The solution was stirred for 8 hours at a concentration of 4.5 mol / L and a speed of 300 rpm and a temperature of 30℃. Then, the solid and liquid were separated by filtration to obtain a sulfonated ketone polymer solution loaded with Mg-Al mixed solution.

[0060] (3) The sulfonated ketone polymer solution with a volume ratio of 1:7 loaded with Mg-Al mixed solution was co-precipitated with concentrated ammonia at 80°C for 6 hours. The concentration of concentrated ammonia used was 8 mol / L. After the reaction, the solution was dried in an oven at 60°C for 8 hours to obtain the polymer material loaded with Mg-Al type layered double hydroxide adsorbent.

[0061] The polymer material-supported Mg-Al type layered double hydroxide adsorbent prepared in this embodiment was applied to phosphate adsorption, and its adsorption capacity was 22 mg / g.

[0062] Example 3

[0063] (1) Wash the surface of 20g of polyether ether ketone powder with water and dry it at 60°C to obtain ketone-based polymer material. Then mix it with 150mL of 98% concentrated sulfuric acid and carry out sulfonation reaction at 75°C for 3.5 hours to obtain sulfonated ketone-based polymer. Clean the sulfonated ketone-based polymer until its conductivity is 75uS and its pH value is 6.75.

[0064] (2) Take 40 mL of sulfonated ketone polymer and 350 mL of Fe-Al mixed solution (Al 3+ The concentration is 1.5 mol / L, Fe 3+The solution was stirred for 6 hours at a concentration of 3 mol / L at a speed of 300 rpm and a temperature of 55℃, and then the solid and liquid were separated by filtration to obtain a sulfonated ketone polymer solution loaded with Fe-Al mixed solution.

[0065] (3) The sulfonated ketone polymer solution with a volume ratio of 1:6 loaded Fe-Al mixed solution was co-precipitated with concentrated ammonia at 80°C for 5 hours. The concentration of concentrated ammonia used was 5 mol / L. After the reaction, the solution was dried in an oven at 60°C for 6 hours to obtain the polymer material loaded Fe-Al type layered double hydroxide adsorbent.

[0066] The polymer-supported Fe-Al type layered double hydroxide adsorbent prepared in this embodiment was applied to the removal of hexavalent chromium ions in water, and its adsorption capacity was 20 mg / g.

[0067] Example 4

[0068] (1) Wash the surface of 20g of polyether ether ketone powder with water and dry it at 60°C to obtain ketone polymer material. Then mix it with 160mL of 98% concentrated sulfuric acid and carry out sulfonation reaction at 75°C for 5 hours to obtain sulfonated ketone polymer. Clean the sulfonated ketone polymer until its conductivity is 75uS and its pH value is 6.78.

[0069] (2) Take 50 mL of sulfonated ketone polymer and 450 mL of Ca-Al mixed solution (Al 3+ The concentration is 1.5 mol / L, Ca 2+ The solution was stirred for 6 hours at a concentration of 5 mol / L at a speed of 300 rpm and a temperature of 50℃. Then, the solid and liquid were separated by filtration to obtain a sulfonated ketone polymer solution loaded with Ca-Al mixed solution.

[0070] (3) The sulfonated ketone polymer solution with a volume ratio of 1:6.4 loaded with Ca-Al mixed solution was co-precipitated with concentrated ammonia at 80°C for 4 hours. The concentration of concentrated ammonia used was 6 mol / L. After the reaction, the solution was dried in an oven at 60°C for 6 hours to obtain the polymer material loaded with Ca-Al type layered double hydroxide adsorbent.

[0071] The polymer-supported Ca-Al type layered double hydroxide adsorbent prepared in this embodiment was applied to the removal of hexavalent chromium ions in water, and its adsorption capacity was 15 mg / g.

[0072] As can be seen from the above embodiments, the present invention provides a polymer-supported X-Al type layered double hydroxide adsorbent and its preparation method. The preparation method of the present invention uses polymer materials as carriers and layered double hydroxides as loading materials, realizing an in-situ synthesis technology that integrates powder synthesis and granulation. The process is simple, and the adsorption capacity of the prepared layered double hydroxide adsorbent is 4-30 mg / g. The adsorption performance is stable and it has great potential for industrial production.

[0073] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polymer-supported X-Al type layered double hydroxide adsorbent, characterized in that, Layered double hydroxide adsorbents use ketone-based polymers as carriers and layered double hydroxides as loading materials; The preparation method of the polymer material-supported X-Al type layered double hydroxide adsorbent includes the following steps: (1) The ketone polymer material is mixed with concentrated sulfuric acid and subjected to sulfonation reaction to obtain sulfonated ketone polymer; (2) The sulfonated ketone polymer and the X-Al mixed solution were mixed and pretreated to obtain a sulfonated ketone polymer solution loaded with X-Al mixed solution; (3) The sulfonated ketone polymer solution loaded with X-Al mixed solution was co-precipitated with concentrated ammonia to obtain a polymer material loaded with X-Al type layered double hydroxide adsorbent. In step (1), the mass-to-volume ratio of the ketone polymer to concentrated sulfuric acid is 1g:5~10mL; The sulfonation reaction is carried out at a temperature of 40~95℃ for 1~12h. The sulfonated ketone polymer has a pH of 6-7 and an electrical conductivity of 0-100 μS. The mass ratio of the layered double hydroxide to the ketone polymer is 0.2~0.8:1; The ketone-based polymer material is polyetheretherketone; The layered double hydroxide includes one or more of lithium aluminum layered double hydroxide, magnesium aluminum layered double hydroxide, calcium aluminum layered double hydroxide, and iron aluminum layered double hydroxide.

2. A method for preparing the polymer material-supported X-Al type layered double hydroxide adsorbent according to claim 1, characterized in that, Includes the following steps: (1) The ketone polymer material is mixed with concentrated sulfuric acid and subjected to sulfonation reaction to obtain sulfonated ketone polymer; (2) The sulfonated ketone polymer and the X-Al mixed solution were mixed and pretreated to obtain a sulfonated ketone polymer solution loaded with X-Al mixed solution; (3) The sulfonated ketone polymer solution loaded with X-Al mixed solution was co-precipitated with concentrated ammonia to obtain a polymer material loaded with X-Al type layered double hydroxide adsorbent. In step (1), the mass-to-volume ratio of the ketone polymer to concentrated sulfuric acid is 1g:5~10mL; The sulfonation reaction is carried out at a temperature of 40~95℃ for 1~12h. The sulfonated ketone polymer has a pH of 6-7 and an electrical conductivity of 0-100 μS.

3. The preparation method according to claim 2, characterized in that, In step (2), the Al in the X-Al mixed solution 3+ The concentration is 0.1~5 mol / L, X n+ The concentration is 0.05~8 mol / L; Among them, X n+ For Li + Mg 2+ Ca 2+ or Fe 3+ .

4. The preparation method according to claim 3, characterized in that, In step (2), the volume ratio of the sulfonated ketone polymer and the X-Al mixed solution is 1:2~10.

5. The preparation method according to claim 4, characterized in that, In step (2), the temperature of the mixing pretreatment is 25~60℃ and the time is 1~10h.

6. The preparation method according to claim 5, characterized in that, In step (3), the volume ratio of the sulfonated ketone polymer solution loaded with X-Al mixed solution to concentrated ammonia is 1:5~10, and the concentration of concentrated ammonia is 1~10 mol / L.

7. The preparation method according to claim 6, characterized in that, In step (3), the temperature of the coprecipitation reaction is 70~85℃ and the time is 2~12h.

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