CN103638902A - Lanthanum-loaded magnetic carbon aerogel microsphere defluorination adsorbent and preparation method - Google Patents

Abstract

The invention provides a fluoride-removing adsorbent for lanthanum-loaded magnetic carbon airgel microspheres and a preparation method thereof, the method comprising: 1) adding carbon airgel microspheres prepared by inverse emulsion polymerization into a solution containing iron salt , the binary mixture of magnetically loaded Fe ₃ O ₄ was prepared by liquid-phase chemical precipitation; 2) The magnetically loaded mixture was added to the lanthanum salt solution and left to prepare a ternary mixture; 3) The ternary mixture was dried and calcined , to prepare microsphere adsorbent for defluorination. The microspheres prepared by the present invention have a maximum adsorption capacity of 113.5mg/g-- for fluoride ions, are easy to recycle, and can be easily separated by adding a magnet, which saves the tedious and energy-consuming suction filtration separation or centrifugal separation process. High, no broken after long-term use, small quality loss, no dissolution, no secondary pollution problems, safe and reliable, suitable for long-term use and in the case of large changes in water flow pressure.

Description

A kind of lanthanum-loaded magnetic carbon airgel microsphere defluoride adsorbent and preparation method

technical field

The invention belongs to the technical field of adsorption materials, in particular to a fluorine-removing adsorbent and a preparation method of lanthanum-loaded magnetic carbon airgel microspheres.

Background technique

Fluorine is one of the essential trace elements in the human body, and it is mainly distributed in bones and teeth in the human body. Appropriate amount of fluorine can enhance the firmness of bones, and has a certain effect on preventing dental caries. The daily intake of fluoride for adults is generally 1.0-1.5 mg, and the appropriate concentration of fluoride in drinking water is 0.5-1.0 mg/L. However, excessive intake of fluoride will damage human health, cause dental fluorosis and skeletal fluorosis, and in severe cases can cause waist and leg pain, joint stiffness, hunchback and even paraplegia, and can also cause thyroid dysfunction, kidney dysfunction, etc. .

High-fluorine water is widely distributed in my country, covering 27 provinces, municipalities and autonomous regions. According to the survey results of the Ministry of Health, about 77 million people in the country drink water with a fluoride content exceeding 1.0 mg/L, and nearly 5 million of them drink The fluorine content of water exceeds 5.0mg/L. A survey in my country's Inner Mongolia area found that the probability of suffering from mild dental fluorosis is close to 50% among people who drink well water with a fluoride ion concentration of about 10mg/L for a long time, and the fluoride content of drinking water is 5-6mg/L groundwater for 10 years Dental fluorosis is common. In addition, animal experiments have shown that high fluorine can promote the absorption and accumulation of a large amount of aluminum, which can easily cause Alzheimer's disease and human aging.

Therefore, the health problems caused by drinking high-fluorine water have attracted the attention of governments and people in various countries. The World Health Organization (WHO) sets the limit value of fluorine in drinking water as 0.6-1.5mg/L, and my country’s drinking water hygiene standard (GB5479-2006), which was officially implemented on July 1, 2007, stipulates the limit of fluorine in drinking water. The value is 1.0mg/L. The implementation of strict standards has put forward higher requirements for high-fluorine water treatment technology. At present, the methods for removing fluoride from drinking water mainly include chemical precipitation and adsorption filtration. In addition, there are ion exchange, electrodialysis, reverse osmosis, electrocoagulation, and electroadsorption. Among them, the adsorption method has high removal efficiency, The effect is stable and it has become a commonly used method for removing fluoride.

The key to the adsorption method lies in the performance of the adsorption material. However, the research and development and practical application of adsorption fluorine removal materials currently have the following problems:

(1) The adsorption capacity of the fluorine removal adsorbent is low, resulting in the consumption of a large amount of adsorbent during the adsorption process;

(2) Some nano-scale fluorine removal adsorbents are small in size, and it is not easy to separate solid and liquid after the adsorption is completed, and there are difficulties in the design of the adsorption process and equipment;

(3) After some nano-adsorbents are bonded and formed, the adsorption capacity drops sharply;

( 4) Some formed adsorbents have poor strength and are easily broken; when they are filled and used in the adsorption tower/tank/column, there are problems caused by the self-weight of the adsorption bed, hydrostatic pressure, water kinetic energy during the treatment process, and instantaneous high-speed water flow during the backwash process. The problem of broken adsorbent particles, on the one hand, will lead to the loss of adsorbent, and the system cannot operate effectively for a long time; on the other hand, the turbidity of the effluent water will increase in a short period of time, and the dissolution and release of chemical elements will cause potential safety hazards in drinking water;

( 5) Some molding processes and molding materials contain harmful substances, which cannot guarantee the safety of drinking water.

Carbon Aerogels is a new type of lightweight nano-porous amorphous carbon material. It is a solid material with ultra-low density and porosity. The porosity can reach 80% - 99.8%. The pore size is generally 1 - 100nm, the specific surface area is between 500 - 1200 m ² /g, and the density can vary from 0.001 - 0.5g/cm ³ . Carbon airgel can prepare microspheres with different particle sizes. Chinese patent (publication number: CN 1011041430 A) patent discloses a preparation method of spherical carbon airgel: phenol-melamine-formaldehyde is used as raw material and pre-polymerized to form The sol is added to the dispersed phase containing the surfactant, and is stirred to form a suspension system. The sol-gel transforms into a spherical hydrogel at 60-85°C, and then the hydrogel undergoes organic solvent conversion and supercritical drying. Spherical organic airgel is prepared, and then subjected to high-temperature pyrolysis to obtain spherical carbon aerogel. Carbon airgel microspheres with a diameter of 0.01-3 mm can be obtained by controlling the stirring speed in the sol-gel process. Carbon airgel has many excellent mechanical, electrical and chemical properties, and can be widely used in adsorption materials, battery materials, electrode materials, chemical sensors and other fields.

Lanthanum is a rare earth element. Studies have shown that oxides of rare earth elements have high adsorption selectivity for fluorine ions, and loading it on carbon airgel materials can improve the adsorption capacity and selectivity of the material for fluorine. For example, Chinese patent (publication number: CN 101234792 A) reported a method for removing fluoride ions in water by alumina loaded with lanthanum. The specific method is: mix alumina and lanthanum salt at a mass ratio of 1-4:1 and roast at 170-400°C. The prepared aluminum oxide loaded with lanthanum oxide is obviously better than traditional adsorption materials in removing fluoride ions in water, and the maximum adsorption capacity reaches 80.8 mg/g. Chinese patent (publication number: CN 101780397 A) has reported a kind of preparation method of the zeolite that is used for removing fluorine load lanthanum: add lanthanum chloride solution in raw material zeolite, adjust solution pH with 28 wt% concentrated ammonia water, impregnate and stir Finally remove the filtrate, dry, and burn at high temperature. After cooling, the remaining lanthanum ions are cleaned and dried to obtain lanthanum oxide-loaded zeolite. The lanthanum oxide-loaded zeolite prepared by this method has a good removal effect on fluoride ions, and the maximum adsorption capacity reaches 7.69 mg/g, and is suitable for water quality with different concentrations and different hardnesses. However, the above-mentioned methods are relatively cumbersome, and the adsorption capacity for fluoride ions needs to be improved.

In the environmental field, magnetic microsphere materials are used as adsorbents, which have the advantages of high mass transfer rate, good solid-liquid contact, pressure drop, and easy separation under the action of an external magnetic field. Magnetic adsorbents can be used to adsorb pollution in aqueous solutions and industrial waste gases. things. After adsorption is complete, the adsorbent can be separated by a simple magnetic process.

The most reported magnetic nanoparticles are mainly nanoparticles of zero-valent iron, Fe ₃ O ₄ and γ-Fe ₂ O ₃ . The methods for loading metals or metal oxides on carbon materials mainly include synchronous loading method, liquid phase chemical deposition method, impregnation method, sol-gel method, hydrothermal synthesis method and vapor phase chemical deposition method. For example, Chinese patent (publication number: CN 101503579 A) reports a method for preparing a composite material of magnetic alloy particles loaded on the surface of carbon nanotubes: the carbon nanotubes are uniformly dispersed into iron, cobalt, and nickel after being purified and activated. In the chloride salt solution, alkaline solution is slowly added dropwise to the solution during vigorous stirring, and the pH value of the solution is adjusted so that iron, cobalt, and nickel ions co-precipitate on the surface of carbon nanotubes in the form of hydroxide according to the alloy ratio when preparing the solution. Remove the precipitate by centrifugation or filtration. After the precipitate is dried, it is heat-treated under a reducing atmosphere to obtain a carbon nanotube composite material loaded with magnetic alloy nanoparticles. Chinese patent (publication number: CN 101823777 A) reports a preparation method of mesoporous carbon CMK-3 loaded with magnetic Fe ₃ O ₄ particles: using mesoporous carbon material CMK-3 as a carrier, a magnetically active metal oxide Iron tetroxide (Fe ₃ O ₄ ) was used as the loading object, ethylene glycol was used as the reducing agent, and the Fe ₃ O ₄ particles were loaded into the mesoporous carbon CMK-3 by equal volume impregnation method and roasting in inert gas. inside the mesoporous pores.

Contents of the invention

The object of the present invention is to provide a kind of lanthanum-loaded magnetic carbon airgel microsphere defluorination adsorbent and preparation method for the problems existing in the above-mentioned prior art. The lanthanum-loaded magnetic carbon airgel microspheres prepared by the method of the present invention have strong fluoride removal and adsorption capacity, are easy to separate, have small mass loss, no dissolution, no secondary pollution problems, are safe and reliable, and are suitable for long-term use and in places where the water flow pressure changes greatly. case use.

In order to achieve the purpose of the present invention, the present invention provides a kind of lanthanum-loaded magnetic carbon airgel microsphere defluorination adsorbent and preparation method on the one hand, comprise the steps that carry out in following order:

1) Carbon airgel microspheres were prepared by inverse emulsion polymerization;

2) Add the carbon airgel microspheres prepared in step 1) into the iron salt-containing solution, stir, heat up to 80°C, add lye, and react for a certain period of time. Preparation of binary mixture carbon aerogels loaded with magnetic Fe ₃ O ₄ by liquid-phase chemical precipitation;

3) Add the magnetic loading mixture prepared in step 2) into the aqueous lanthanum salt solution and let it stand to prepare a ternary mixture;

4) The ternary mixture prepared in step 3) is dried and calcined.

The preparation process of the carbon airgel microspheres described in step 1) is as follows: add resorcinol, formaldehyde, and anhydrous sodium carbonate in proportion to an appropriate amount of distilled water to dissolve, and transfer to a certain volume of dispersed phase containing surfactant , stirring at 80° C. for a period of time at a controlled rotational speed to obtain dispersed organic wet gel microspheres. The organic wet gel microspheres were separated by filtration and washed 3-5 times with distilled water. The obtained organic wet gel microspheres are placed in acetone for solvent replacement, then dried in a fume hood at normal temperature and pressure, and finally carbonized at high temperature under the protection of an inert gas to obtain the carbon airgel microspheres.

In particular, the particle size and morphology of the carbon airgel microspheres is shown in the scanning electron microscope (SEM) image of Figure 1, the particle size is about 10-80 μm, the porosity is 80%-98%, and the typical pore size is less than 50nm. The specific surface area is as high as 600-1000m ² /g, and the density is 0.05-0.80g/cm ³ .

Wherein, the weight ratio of carbon airgel microspheres and magnetic material Fe ₃ O ₄ in step 2) is 5-45:55-95.

Wherein, the concentration of the aqueous lanthanum salt solution described in step 3) is 0.1-1.5 mol/L, and the lanthanum salt is preferably lanthanum nitrate.

In particular, the rest time is 24-72 hours.

In particular, it also includes drying the ternary mixture, wherein the temperature of the drying treatment is 60-120° C. and the time is 10-24 hours.

In particular, the calcination treatment is to put the dried fluorine-removing ternary mixture into a muffle furnace, heat it to 450-600° C., and heat it for 3-10 hours.

Another aspect of the present invention provides a fluorine-removing lanthanum-loaded magnetic carbon airgel microsphere adsorbent prepared according to the above method.

The lanthanum-loaded magnetic carbon airgel microsphere adsorbent prepared by the present invention has the following advantages:

1. The lanthanum-loaded magnetic carbon airgel microsphere adsorbent of the present invention has good ion selectivity, and has high selectivity for removing ions (fluoride ions) for its target. Other common anions in water have no obvious ions in the range of drinking water. Influence;

2. The present invention removes fluorine-loaded lanthanum magnetic carbon airgel through covalent bond chemical adsorption, electrostatic adsorption, ion exchange adsorption, etc., to adsorb and fix fluorine compounds in drinking water, and has a high adsorption capacity for fluorine. Under neutral conditions, the saturated adsorption capacity of the magnetic carbon airgel microsphere adsorbent is 113.5 mg/g;

3. The magnetism of the lanthanum-loaded magnetic carbon airgel microsphere adsorbent of the present invention is high, and its saturation magnetization value is greater than 77emu/g---, and it is easy to separate after adsorption;

4. The lanthanum-loaded magnetic carbon airgel microsphere adsorbent of the present invention has high cohesive strength, high crushing strength, and a dry compressive strength of more than 45N. Use in case;

5. The lanthanum-loaded magnetic carbon airgel microsphere adsorbent of the present invention has small mass loss during use, no dissolution, no swelling, no toxicity, no secondary pollution, and safe and reliable water quality after treatment.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

The lanthanum-loaded magnetic carbon airgel microsphere fluorine-removing adsorbent and the preparation method comprise the following steps:

1. Preparation of carbon airgel microspheres

Dissolve resorcinol, formaldehyde, and anhydrous sodium carbonate in an appropriate amount of distilled water at a molar ratio of 1:2:0.01, and stir to dissolve to obtain a hydrosol. Transfer the dissolved solution to the dispersed phase cyclohexane solution containing SPAN-80 with a volume ratio of 1:100, and stir at 120r/min at 80°C until dispersed organic wet gel particles are formed. The organic wet gel particles separated by filtration were soaked in acetone for 3 days, then placed in a fume hood and dried naturally to constant weight to obtain xerogel microspheres, which were carbonized and cracked at 850°C for 5 hours under the protection of _N2 to obtain carbon gas gel microspheres. The carbon airgel microspheres have a particle size of 40-60 μm and a specific surface area of 605 m ² /g;

2. Carbon airgel microspheres loaded with magnetic nano Fe ₃ O ₄ particles

Add FeCl ₂ .4H ₂ O and FeCl ₃ .6H ₂ O to an appropriate amount of distilled water at a molar ratio of 1:2 to dissolve, add 2 g of carbon airgel microspheres prepared in step 1, stir, and add 5 ml when the temperature rises to 80 °C Ammonia water, continue to react for 1 hour to obtain magnetically loaded carbon airgel microspheres, use a magnet to separate the magnetic carbon airgel microspheres, wash with distilled water until neutral, dry at 60°C, and set aside;

3. Magnetic carbon airgel microspheres loaded with lanthanum

Soak the magnetic carbon airgel microspheres prepared in step 2 in an appropriate volume of 0.5mol/L _-- lanthanum nitrate solution, place for 24 hours, separate with a magnet, dry at 60°C, and activate at 450°C for 10 hours, The lanthanum-loaded magnetic carbon airgel microspheres, which can be used for the removal of fluoride ions in water, have been obtained. The saturation magnetization value has reached 79.2 emu/g _--- , and the dry compressive strength is >45N;

Application of lanthanum-loaded magnetic carbon airgel microspheres adsorbent:

Take 0.1 g of the prepared lanthanum-loaded magnetic carbon airgel microsphere adsorbent and place it in 100 ml of a solution with a fluoride ion concentration of 1-200 mg/L. After oscillating and adsorbing at room temperature for 24 hours, use a magnet to separate and measure the fluoride ion concentration of the solution. The adsorption capacity was calculated, and the maximum adsorption capacity of the new magnetic carbon airgel microsphere adsorbent for fluorine was calculated to be 92mg/g according to the Langmuir equation fitting.

Example 2

The lanthanum-loaded magnetic carbon airgel microsphere fluorine-removing adsorbent and the preparation method comprise the following steps:

1. Preparation of carbon airgel microspheres

Dissolve resorcinol, formaldehyde, and anhydrous sodium carbonate in an appropriate amount of distilled water at a molar ratio of 1:2:0.02, and stir to dissolve to obtain a hydrosol. Transfer the dissolved solution to the dispersed phase cyclohexane solution containing SPAN-80 at a volume ratio of 2:100, and stir at 240 r/min at 70°C until dispersed organic wet gel particles are formed. The organic wet gel particles separated by filtration were soaked in acetone for 2 days, then placed in a fume hood and dried naturally to constant weight to obtain xerogel microspheres, which were carbonized and cracked at 950°C for 4 hours under the protection of _N2 to obtain carbon gas gel microspheres. The carbon airgel microspheres have a particle size of 30-45 μm and a specific surface area of 550 m ² /g;

2. Carbon airgel microspheres loaded with magnetic nano Fe ₃ O ₄ particles

Add FeSO ₄ .7H ₂ O and Fe ₂ (SO ₄ ) ₃ to an appropriate amount of distilled water at a molar ratio of 1:1 to dissolve, add 3 g of carbon airgel microspheres prepared in step 1, stir, and add when the temperature rises to 80°C Appropriate amount of 0.5mol/L NaOH solution, continue to react for 1 hour to obtain magnetically loaded carbon airgel microspheres, use a magnet to separate the magnetic carbon airgel microspheres, wash with distilled water until neutral, dry at 60°C, and set aside;

3. Magnetic carbon airgel microspheres loaded with lanthanum

Soak the magnetic carbon airgel microspheres prepared in step 2 in an appropriate volume of 0.5mol/L lanthanum sulfate solution, place for 48 hours, separate with a magnet, dry at 80°C, and activate at 550°C for 8 hours to obtain usable Magnetic carbon airgel microspheres loaded with lanthanum for removal of fluoride ions in water, the saturation magnetization value reached 77.4emu/g _--- , and the dry compressive strength>45N;

Application of lanthanum-loaded magnetic carbon airgel microspheres adsorbent:

Take 0.1 g of the prepared lanthanum-loaded magnetic carbon airgel microsphere adsorbent and place it in 100 ml of a solution with a fluoride ion concentration of 1-200 mg/L. After oscillating and adsorbing at room temperature for 24 hours, use a magnet to separate and measure the fluoride ion concentration of the solution. And calculate the adsorption capacity, according to the Langmuir equation fitting calculation, the maximum adsorption capacity of the novel magnetic carbon airgel microsphere adsorbent for fluorine is 95 mg/g.

Example 3

The lanthanum-loaded magnetic carbon airgel microsphere fluorine-removing adsorbent and the preparation method comprise the following steps:

1. Preparation of carbon airgel microspheres

Dissolve resorcinol, formaldehyde, and anhydrous sodium carbonate in an appropriate amount of distilled water at a molar ratio of 1:2:0.01, and stir to dissolve to obtain a hydrosol. Transfer the dissolved solution to the dispersed phase cyclohexane solution containing SPAN-80 at a volume ratio of 5:100, and stir at 480 r/min at 80°C until dispersed organic wet gel particles are formed. The organic wet gel particles separated by filtration were soaked in acetone for 3 days, then placed in a fume hood to dry naturally to constant weight to obtain xerogel microspheres, and the xerogel microspheres were carbonized and cracked at 1050°C for 3 hours under the protection of _N2 to obtain carbon gas gel microspheres. The carbon airgel microspheres have a particle size of 20-32 μm and a specific surface area of 500 m ² /g;

2. Carbon airgel microspheres loaded with magnetic nano Fe ₃ O ₄ particles

Add FeSO ₄ .7H ₂ O and Fe ₂ (SO ₄ ) ₃ to an appropriate amount of distilled water at a molar ratio of 1:1 to dissolve, add 4 g of carbon airgel microspheres prepared in step 1, stir, and add when the temperature rises to 80°C 30ml of ammonia water, continue to react for 1.5 hours to obtain magnetically loaded carbon airgel microspheres, use a magnet to separate the magnetic carbon airgel microspheres, wash with distilled water until neutral, dry at 60°C, and set aside;

3. Magnetic carbon airgel microspheres loaded with lanthanum

Soak the magnetic carbon airgel microspheres prepared in step 2 in an appropriate volume of 1 mol/L lanthanum nitrate solution, place for 72 hours, separate with a magnet, dry at 80°C, and activate at 600°C for 6 hours to obtain usable Magnetic carbon airgel microspheres loaded with lanthanum for removal of fluoride ions in water, the saturation magnetization value reached 79emu/g _--- , and the dry compressive strength>46N;

Application of lanthanum-loaded magnetic carbon airgel microspheres adsorbent:

Take 0.1 g of the prepared lanthanum-loaded magnetic carbon airgel microsphere adsorbent and place it in 100 ml of a solution with a fluoride ion concentration of 1-200 mg/L. After oscillating and adsorbing at room temperature for 24 hours, use a magnet to separate and measure the fluoride ion concentration of the solution. And calculate the adsorption capacity, according to the Langmuir equation fitting calculation, the maximum adsorption capacity of the novel magnetic carbon airgel microsphere adsorbent for fluorine is 97mg/g.

Example 4

The lanthanum-loaded magnetic carbon airgel microsphere fluorine-removing adsorbent and the preparation method comprise the following steps:

1. Preparation of carbon airgel microspheres

Dissolve resorcinol, formaldehyde, and anhydrous sodium carbonate in an appropriate amount of distilled water at a molar ratio of 1:2:0.01, and stir to dissolve to obtain a hydrosol. Transfer the dissolved solution to the dispersed phase cyclohexane solution containing SPAN-80 at a volume ratio of 2:100, and stir at 480 r/min at 80°C until dispersed organic wet gel particles are formed. The organic wet gel particles separated by filtration were soaked in acetone for 3 days, then placed in a fume hood and dried naturally to constant weight to obtain xerogel microspheres, which were carbonized and cracked at 950°C for 5 hours under the protection of _N2 to obtain carbon gas gel microspheres. The carbon airgel microspheres have a particle size of 20-25 μm and a specific surface area of 550 m ² /g;

2. Carbon airgel microspheres loaded with magnetic nano Fe ₃ O ₄ particles

Add FeCl ₂ .4H ₂ O and FeCl ₃ .6H ₂ O to an appropriate amount of distilled water at a molar ratio of 1:2 to dissolve, add 2 g of carbon airgel microspheres prepared in step 1, stir, and add 10 ml when the temperature rises to 80°C Ammonia water, continue to react for 2 hours to obtain magnetically loaded carbon airgel microspheres, use a magnet to separate the magnetic carbon airgel microspheres, wash with distilled water until neutral, dry at 60°C, and set aside;

3. Magnetic carbon airgel microspheres loaded with lanthanum

Soak the magnetic carbon airgel microspheres prepared in step 2 in an appropriate volume of 1mol/L lanthanum sulfate solution, place for 72 hours, separate with a magnet, dry at 120°C, and activate for 4 hours at 650°C to obtain The lanthanum-loaded magnetic carbon airgel microspheres removed by fluoride ions in water have a saturation magnetization value of 79.2emu/g _--- , and a dry compressive strength of >48N;

Application of lanthanum-loaded magnetic carbon airgel microspheres adsorbent:

Take 0.1 g of the prepared lanthanum-loaded magnetic carbon airgel microsphere adsorbent and place it in 100 ml of a solution with a fluoride ion concentration of 1-200 mg/L. After oscillating and adsorbing at room temperature for 24 hours, use a magnet to separate and measure the fluoride ion concentration of the solution. According to the Langmuir equation fitting calculation, the maximum adsorption capacity of the novel magnetic carbon airgel microsphere adsorbent for fluorine is 113.5 mg/g.

Example 5

The lanthanum-loaded magnetic carbon airgel microsphere fluorine-removing adsorbent and the preparation method comprise the following steps:

1. Preparation of carbon airgel microspheres

Dissolve resorcinol, formaldehyde, and anhydrous sodium carbonate in an appropriate amount of distilled water at a molar ratio of 1:2:0.01, and stir to dissolve to obtain a hydrosol. Transfer the dissolved solution to the dispersed phase cyclohexane solution containing SPAN-80 at a volume ratio of 10:100, and stir at 480 r/min at 80°C until dispersed organic wet gel particles are formed. The organic wet gel particles separated by filtration were soaked in acetone for 3 days, then placed in a fume hood and dried naturally to constant weight to obtain xerogel microspheres, which were carbonized and cracked at 1050°C for 2 hours under the protection of _N2 to obtain carbon gas gel microspheres. The carbon airgel microspheres have a particle size of 16-25 μm and a specific surface area of 660 m ² /g;

2. Carbon airgel microspheres loaded with magnetic nano Fe ₃ O ₄ particles

Add FeCl ₂ .4H ₂ O and FeCl ₃ .6H ₂ O to an appropriate amount of distilled water at a molar ratio of 1:2 to dissolve, add 6g of carbon airgel microspheres prepared in step 1, stir, and add 20ml when the temperature rises to 80°C Ammonia water, continue to react for 4 hours to obtain magnetically loaded carbon airgel microspheres, use a magnet to separate the magnetic carbon airgel microspheres, wash with distilled water until neutral, dry at 60°C, and set aside;

3. Magnetic carbon airgel microspheres loaded with lanthanum

Soak the magnetic carbon airgel microspheres prepared in step 2 in an appropriate volume of 1mol/L lanthanum nitrate solution, place for 24 hours, separate with a magnet, dry at 80°C, and activate for 6 hours at 500°C to obtain Lanthanum-loaded magnetic carbon airgel microspheres for fluoride ion removal from water. Its saturation magnetization value reached 78.5emu/g _--- , and its dry compressive strength was >48N;

Application of lanthanum-loaded magnetic carbon airgel microspheres adsorbent:

Take 0.1 g of the prepared lanthanum-loaded magnetic carbon airgel microsphere adsorbent and place it in 100 ml of a solution with a fluoride ion concentration of 1-200 mg/L. After oscillating and adsorbing at room temperature for 24 hours, use a magnet to separate and measure the fluoride ion concentration of the solution. The adsorption capacity was calculated, and the maximum adsorption capacity of the new magnetic carbon airgel microsphere adsorbent for fluorine was calculated to be 106 mg/g according to the Langmuir equation fitting.

Claims (9)

1. a preparation method for carrying lanthanum magnetic carbon airgel microspheres to remove fluorine adsorbent, comprising the steps carried out in the following order: 1) Add the carbon airgel microspheres prepared by the inverse emulsion polymerization method into the solution containing iron salt, stir, raise the temperature to 80°C, add alkali solution, react for a certain period of time, and prepare magnetically loaded Fe ₃ by liquid phase chemical precipitation A binary mixture of O ₄ ; 2) Add the magnetic loading mixture prepared in step 1) to the aqueous lanthanum salt solution and let it stand to prepare a ternary mixture; 3) The ternary mixture prepared in step 2) is dried and calcined. 2. The preparation method according to claim 1, characterized in that the carbon airgel microspheres described in step 1) can be completed through the following process: adding resorcinol, formaldehyde, and anhydrous sodium carbonate to the Dissolve in an appropriate amount of distilled water, transfer to a certain volume of dispersed phase containing surfactant, and stir at 80°C for a period of time at a controlled speed to obtain dispersed organic wet gel microspheres; filter and separate the above organic wet gel microspheres, and use distilled water Wash 3 to 5 times; put the obtained organic wet gel microspheres into acetone for solvent replacement, then dry them at normal temperature and pressure in a fume hood, and finally carbonize at high temperature under the protection of an inert gas to obtain carbon airgel microspheres. ball. 3. The preparation method according to claim 1 or 2, characterized in that the weight ratio of carbon airgel microspheres to magnetic material _Fe3O4 in step ₂ ) is 5-45:55-95. 4. The preparation method according to claim 1 or 2, characterized in that the reaction time of the carbon airgel microspheres loaded with magnetic Fe ₃ O ₄ in step 2) is 1-4 hours. 5. The preparation method according to claim 1 or 2, characterized in that the concentration of the lanthanum salt solution described in step 3) is 0.5-1.5 mol/L. 6. The preparation method according to claim 1 or 2, characterized in that the binary mixture in step 3) is placed in the lanthanum salt solution for 24-72 hours. 7. The preparation method according to claim 1 or 2, characterized in that the drying temperature in step 4) is 60-120°C, and the drying time is 10-24 hours. 8. The preparation method according to claim 1 or 2, characterized in that the calcination temperature in step 4) is 450-600°C, and the calcination time is 3-10 hours. 9. A lanthanum-loaded magnetic carbon airgel microsphere adsorbent for fluoride ion removal, characterized in that it is prepared according to any one of claims 1 to 8.

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