CN111992183A

CN111992183A - Amino and Fe (III) dual-functionalized spherical mesoporous silica adsorption material and preparation method and application thereof

Info

Publication number: CN111992183A
Application number: CN202010856378.7A
Authority: CN
Inventors: 张婷; 吕荣涛; 高志襄
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2020-11-27

Abstract

The invention discloses an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material and a preparation method and application thereof, the preparation method comprises the steps of preparing main spherical silica by hydrolyzing ethyl orthosilicate (TEOS) serving as a silicon source under an alkaline condition, then changing the main spherical silica into spherical mesoporous silica by pseudomorphic conversion reaction to increase the specific surface area of the spherical mesoporous silica, and finally grafting amino and Fe (III) on the surface of the spherical mesoporous silica to prepare the amino and Fe (III) dual-functionalized spherical mesoporous silica composite material, wherein the amino and Fe (III) dual-functionalized spherical mesoporous silica composite material can realize the adsorption of more than 99.24 percent of As (V) only in 1min in the process of adsorbing As (V) in water, and the adsorption speed is far higher than that of the silica adsorbing material in the prior art.

Description

Amino and Fe (III) dual-functionalized spherical mesoporous silica adsorption material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of adsorption material preparation, and particularly relates to an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorption material, and a preparation method and application thereof.

Background

Arsenic (As) is a toxic and harmful element widely distributed in water. Various degrees of arsenic contamination of drinking water have been encountered in many countries around the world, such as China, the United states, Japan, etc. (Bissen M, Frimel F H. exhibited-a review. part I: Occurrenew, toxity, speciality, Mobility [ J ]. Acta hydrochemica et hydrobiologica,2003,31(1): 9-18). Drinking water containing arsenic for a long time may adversely affect the nervous system, cardiovascular system, gastrointestinal tract and respiratory system of human, and even induce canceration. Therefore, the research on the efficient, rapid and economic arsenic removal technology has great practical significance. Compared with other methods, the adsorption method has the advantages of simple operation, low cost, easy waste treatment and the like, and is concerned. Fe (III) has high affinity to arsenic and is easy to complex with arsenic to form a complex, so that the iron-based adsorption material is widely used in the field of arsenic removal. However, iron-based adsorbents generally adsorb slowly, requiring several hours to achieve good removal. Therefore, the development of high-efficiency and rapid arsenic removal materials is a problem to be solved urgently.

The spherical silicon dioxide has stable property, adjustable particle size and more silicon hydroxyl groups on the surface, is convenient to modify and is a better adsorption material. The spherical silicon dioxide is changed into a porous material after pseudomorphic transformation, so that the specific surface area is increased, and the adsorption is facilitated. However, the adsorption capacity of silicon hydroxyl groups to arsenic is weak, and the silicon hydroxyl groups are generally modified to improve the adsorption performance. Common modification methods are to introduce new functional groups such as amino, thiol, etc. Khdary et al functionalize the surface of spherical silica with mercapto group, the modified adsorbent has better removal effect on As (III), and can reach adsorption equilibrium within 30 minutes (Khdary NH, Gassim AEH, Howard AG, Saktive TS, Seal S. Synthesis and modification of a catalyst-submicron scanner for real-time extraction and purification of As (III), Analytical Methods 2018,10, 245-. Although the adsorption equilibrium time in this report has been greatly shortened, the requirement for rapid adsorption has not yet been met for real industrial applications.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material, and a preparation method and application thereof.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention relates to a preparation method of an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material, which comprises the following steps:

step (1) preparation of spherical silica

Mixing absolute ethyl alcohol (EtOH), ammonia water and Tetraethoxysilane (TEOS), reacting, and carrying out solid-liquid separation to obtain spherical silicon dioxide;

step (2) preparation of spherical mesoporous silica

Adding anhydrous ethanol (EtOH), Cetyl Trimethyl Ammonium Bromide (CTAB) and H₂O, NaOH, mixing to obtain a mixed solution, adding the spherical silica obtained in the step (1) into the mixed solution, carrying out hydrothermal reaction, carrying out solid-liquid separation, and calcining the obtained solid phase to obtain the spherical mesoporous silica;

step (3) amino functionalization

Dispersing the spherical mesoporous silica obtained in the step (2) in an organic solvent, then adding Aminopropyltrimethoxysilane (APTES), uniformly mixing, and carrying out solvothermal reaction to obtain amino functionalized spherical mesoporous silica;

step (4) Fe (III) functionalization

Dispersing the amino functionalized spherical mesoporous silica obtained in the step (3) in FeCl₃Stirring the solution for reaction, and carrying out solid-liquid separation to obtain the amino and Fe (III) -bifunctional spherical mesoporous silica composite material.

According to the preparation method, main spherical silicon dioxide is prepared by hydrolyzing Tetraethoxysilane (TEOS) serving as a silicon source under an alkaline condition, then the spherical silicon dioxide is changed into spherical mesoporous silicon dioxide through pseudomorphic transformation reaction so as to increase the specific surface area of the spherical mesoporous silicon dioxide, and finally amino and Fe (III) are grafted on the surface of the spherical mesoporous silicon dioxide, so that the spherical mesoporous silicon dioxide composite material with double functions of amino and Fe (III) is prepared.

In the invention, double functionalization of amino and Fe (III) is adopted, although other multifunctional groups can also have certain adsorption effect on arsenic; however, in any combination, the adsorption rate of the present invention cannot be achieved in terms of the time required for adsorption.

The inventor finds that the spherical silica prepared by hydrolyzing Tetraethoxysilane (TEOS) serving as a silicon source under an alkaline condition has high surface silicon hydroxyl concentration, and excellent adsorption efficiency can be ensured after subsequent modification, while if the spherical silica prepared by other methods is adopted, the subsequent modification effect is poor and the adsorption efficiency is low due to the low surface silicon hydroxyl concentration of the spherical mesoporous silica.

In addition, only FeCl can be adopted in the process of Fe (III) functionalization₃Can be used as an iron source to realize high-efficiency and quick adsorption finally if Fe (NO) is selected₃)₃，NO^-May react with amino groups resulting in failure of modification; selection of Fe₂(SO₄)₃，SO₄ ^2-Competitive adsorption may occur, resulting in a decrease in the adsorption effect.

Preferably, in the step (1), the volume ratio of the ethyl orthosilicate to the absolute ethyl alcohol is 5-10: 160.

preferably, in the step (1), the volume ratio of the ammonia water to the absolute ethyl alcohol is 10-20: 160

Preferably, in the step (1), NH is dissolved in the ammonia water₃The mass fraction of (A) is 25-28%.

Preferably, in the step (1), the reaction is carried out at room temperature under stirring, the rotation speed of the stirring is 750-800 rpm, and the reaction time is 16-24 h.

Preferably, in the step (1), the solid-liquid separation mode is centrifugation, the solid phase obtained after centrifugation is washed by absolute ethyl alcohol, dried to constant weight at 70-80 ℃, and ground into powder to obtain the spherical silicon dioxide.

Preferably, in step (2), the molar ratio of spherical silica to CTAB is 1: 0.1-0.3. the molar ratio of the spherical silica to NaOH is 1: 0.3-0.6.

preferably, in step (2), the spherical silica is mixed with H₂The molar ratio of O is 1: 500-1000.

preferably, in the step (2), the molar ratio of the spherical silica to EtOH is 1: 50-100.

preferably, in the step (2), the spherical silica obtained in the step (1) is added to the mixed solution, stirred at room temperature for 20-30 min, and then transferred to a hydrothermal reaction kettle for hydrothermal reaction.

Further preferably, in the step (2), the temperature of the hydrothermal reaction is 80-120 ℃ and the time is 20-30 h.

Preferably, in the step (2), the solid-liquid separation is performed by centrifugation, the solid phase obtained after centrifugation is alternately washed with ultrapure water and absolute ethyl alcohol, dried at 70-80 ℃ to constant weight, ground into powder, and the obtained powder is calcined.

Preferably, in the step (2), the calcination is carried out in an air atmosphere, the calcination temperature is 500-600 ℃, the calcination time is 5-8 h, and the temperature rise rate is 1-20 ℃/min.

CTAB is removed by calcination, and after the calcination is finished, the CTAB is cooled and ground into powder to obtain the spherical mesoporous silica.

Preferably, in the step (3), the solid-liquid mass volume ratio of the spherical mesoporous silica to the organic solvent is 1 g: 80-120 mL.

Preferably, in step (3), the organic solvent is anhydrous toluene. The inventors have found that the use of dry toluene as solvent for the reaction system ensures successful amino-functional modification, while other systems, such as ethanol, may fail to provide modification.

Preferably, in the step (3), the addition amount of the Aminopropyltrimethoxysilane (APTES) is 5-10: 4. the amount of APTES used as an amino-functional agent is controlled within the preferred range, and the optimum adsorption effect can be obtained.

Preferably, in the step (3), Aminopropyltrimethoxysilane (APTES) is added, stirred for 20-30 min to be uniformly mixed, and then transferred to a reaction kettle to be subjected to solvothermal reaction.

Preferably, in the step (3), the temperature of the solvothermal reaction is 100-130 ℃, and the time of the solvothermal reaction is 5-10 h.

Preferably, in the step (3), the product obtained by solvothermal reaction is cooled to room temperature, washed with EtOH for 3 times, dried in vacuum at 50-80 ℃ to constant weight, and ground into powder to obtain the amino functionalized spherical mesoporous silica.

Preferably, in the step (4), the amino-functionalized spherical mesoporous silica and FeCl are used₃The solid-liquid mass volume ratio of the solution is 0.1 g: 7-12 mL; the FeCl₃The concentration of the solution is 0.05-0.2M. FeCl is added₃When the amount of the solution added is controlled within the preferable range, the optimum adsorption effect can be obtained, and if the amount is too small, the adsorption effect is affected.

Preferably, in the step (4), the rotation speed of the stirring reaction is 750-800 rpm, and the time is 1-3 h. .

Preferably, in the step (4), the solid-liquid separation mode is centrifugation, the solid phase obtained after centrifugation is washed by absolute ethyl alcohol, and is dried in vacuum at 50-80 ℃ to constant weight, and is ground into powder to obtain the amino and Fe (III) dual-functionalized spherical mesoporous silica submicron composite material.

The invention also provides an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material prepared by the preparation method.

The particle size of the amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material is submicron.

The invention also provides an application of the amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material prepared by the preparation method, and the amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material is applied to adsorbing As (V) in water.

The application method comprises the following steps: adding the amino and Fe (III) dual-functionalized spherical mesoporous silica submicron composite material into water containing As (V), adjusting the pH value to 5-10, stirring the solution for more than or equal to 1min, and filtering.

Advantageous effects

The method comprises the steps of preparing main spherical silicon dioxide by hydrolyzing Tetraethoxysilane (TEOS) serving as a silicon source under an alkaline condition, changing the main spherical silicon dioxide into spherical mesoporous silicon dioxide by pseudomorphic transformation reaction to increase the specific surface area of the spherical mesoporous silicon dioxide, and grafting amino and Fe (III) on the surface of the spherical mesoporous silicon dioxide to prepare the spherical mesoporous silicon dioxide composite material with dual functions of the amino and the Fe (III).

When the amino and Fe (III) difunctional spherical mesoporous silica composite material obtained by the invention is applied to adsorbing As (V) in water, the balance can be achieved within 1min, and when the initial concentration of As (V) is less than 1mg/L, the removal rate of As (V) can reach 99.24%, and the standard of drinking water can be achieved (less than 10 mug/L); when the initial concentration of As (V) is less than 10mg/L, the removal rate can reach 92.48 percent; the removal rate continues to decrease as the initial concentration of as (v) continues to increase, and can be solved by increasing the amount of the adsorbent added. The maximum adsorption amount of As (V) by the adsorbent was calculated to be 43.33mg/g by isothermal adsorption and by using a Langmuir fitting curve.

Therefore, the adsorption material provided by the invention has the characteristics of extremely high adsorption speed, balance reaching only over 1min and good removal effect, particularly has excellent removal effect on low-concentration As (V), and can reach the drinking water standard for water with As (V) concentration lower than 1 mg/L.

Drawings

FIG. 1 is a scanning electron microscope image of the functionalized spherical mesoporous silica prepared in example 1.

Fig. 2 is a distribution diagram of the particle size of the functionalized spherical mesoporous silica prepared in example 1.

FIG. 3 is an infrared spectrum of the functionalized spherical mesoporous silica prepared in example 1.

FIG. 4 is a kinetic curve of the adsorption of As (V) on the functionalized spherical mesoporous silica prepared in example 1.

FIG. 5 is an adsorption isotherm of As (V) adsorbed by the functionalized spherical mesoporous silica prepared in example 1.

FIG. 6 is a graph showing the effect of pH on the adsorption efficiency of the functionalized spherical mesoporous silica As (V) prepared in example 1.

FIG. 7 shows the interference of coexisting ions on the adsorption of the functionalized spherical mesoporous silica prepared in example 1.

Detailed Description

The invention will be further elucidated with reference to the drawings and the embodiments without being limited thereto;

example 1

Preparation of amino and Fe (III) difunctional spherical mesoporous silica submicron composite material

(1) Preparation of spherical silica: 160mL of absolute ethanol (EtOH), 16mL of concentrated ammonia water and 7g of ethyl orthosilicate were mixed and stirred at 750-. After the reaction is finished, recovering and purifying the silicon spheres by multiple times of centrifugation and absolute ethyl alcohol washing, drying for 12h at 70-80 ℃ to constant weight, and grinding into powder.

(2) Preparation of spherical mesoporous silica: the silica spheres (0.352g) obtained in (1) were dispersed in EtOH (20.24mL), CTAB (0.4g), H₂O (80mL) and NaOH (0.104g) at room temperature for 30min, the molar ratio of each component being 1SiO₂:0.18CTAB:0.44NaOH:750H₂O:75 EtOH. And then transferring the mixture into a polytetrafluoroethylene lining hydrothermal reaction kettle for hydrothermal reaction, and keeping the temperature at 100 ℃ for 24 hours. After the reaction was completed, the product was collected by centrifugation and washed alternately 6 times with ultrapure water and EtOH. Drying the product at 70 ℃ for 12h, grinding the product into powder, calcining the powder in air at 550 ℃ for 6h (the heating rate is 20 ℃/min), removing CTAB from the silica spheres, and grinding the powder to obtain the spherical mesoporous silica.

(3) Amino functionalization: dispersing 0.4g of the spherical mesoporous silica obtained in the step (2) in 40mL of anhydrous toluene, adding 0.7g of Aminopropyltrimethoxysilane (APTES), stirring for 30min to uniformly mix, uniformly mixing, and then putting into a reaction kettle to react for 8h at 120 ℃. After cooling to room temperature, washing with absolute ethyl alcohol for 3 times, and vacuum drying at 60 ℃ for 8 h. Grinding into powder to obtain the amino functionalized spherical mesoporous silica.

(4) Fe (iii) functionalization: dispersing 0.4g of the amino functionalized spherical mesoporous silica obtained in (3) in 40mL of 0.1M FeCl₃The solution was stirred at 750rpm for 3h, the product was centrifuged, washed 3 times with absolute ethanol and dried under vacuum at 60 ℃ for 8 h. Grinding into powder to obtain the submicron composite material of the amino group and Fe (III) dual-functionalized spherical mesoporous silica.

As can be seen from the scanning electron microscope image, the prepared material is gathered together in a spherical shape, and a large number of pore channels are formed on the surface. As can be seen from the particle size distribution diagram of the adsorbing material, the particle size distribution of more than 70 percent of the spheres is between 340 nm and 400nm, and the average size is about 379 +/-30 nm. This proves that the spherical mesoporous material is successfully synthesized.

Infrared spectroscopic analysis

And analyzing the functional groups on the surface of the adsorbing material by using a Fourier infrared spectrometer. 473. 800, 1080 and 1220cm^-1Is a characteristic peak of Si-O-Si, and forms silicon spheres through crosslinking. 940cm^-1The peak at (A) is a characteristic peak of Si-OH. 690cm^-1A bending vibration peak at N-H of 2940cm^-1The characteristic peak of the carbon chain C-H proves that the amino group is grafted on the surface of the silicon sphere. 1509cm^-1Is NH₃ ⁺Characteristic peak of (D), indicating NH₂Is protonated by Fe (III) and combined with Fe (III). This demonstrates the successful functionalization of fe (iii).

Condition exploration in adsorption applications

Optimization of adsorption pH

A series of As (V) -containing solutions with pH of 1-12 are prepared by dilute NaOH and dilute hydrochloric acid, and the influence of pH on the adsorption effect is optimized. As a result, the optimum pH of the adsorbent was 7, and the adsorption effect was good in the range of pH 5 to 10. When the pH value is 7-10, the pH value is increased, and the adsorption effect is basically kept unchanged; when the pH value is more than 10, the adsorption effect is reduced greatly, and the adsorption material has almost no effect on As (V)Has adsorption effect. This is mainly due to OH under strongly alkaline conditions^–Produces a strong competitive effect on As (V) and preferentially binds with Fe on the surface of the adsorbing material. When the pH is 3-6, the pH is reduced, and the adsorption effect is slightly reduced; when the pH is 2, the adsorption effect is reduced by half; at a pH of 1, the adsorption effect of the adsorbent on As (V) is completely lost, and a part of Fe is detected in the solution. This indicates that the Fe on the surface of the adsorbent falls off under strong acid conditions, resulting in a drastic decrease in the adsorption effect. The optimum adsorption pH is therefore 7.

Adsorption of As (V) in water by adsorbent material

The effect on adsorbed As (V) was investigated by varying the adsorption time and initial adsorption concentration. The As (V) -containing solution was adjusted to pH 7, adsorbent material (0.4g/L) was added and the kinetics studied by shaking at 250rpm for various times at 25 ℃. As a result, the adsorption speed of the material is very high, and the adsorption balance can be achieved in only 1 minute. Initial as (v) concentrations were varied and adsorption isotherms were studied and fitted using Langmuir and Freundlich models. As a result, when the initial concentration of As (V) is less than 1mg/L, the removal rate of As (V) can reach 99.24%, and the standard of drinking water (<10 mug/L) can be reached; when the initial concentration of As (V) is less than 10mg/L, the removal rate can reach 92.48 percent; the maximum adsorption amount of the material to As (V) is 43.33mg/g, and the adsorption isotherm is more consistent with the Langmuir model. It is presumed that the adsorption process is monolayer adsorption. The material has removal effect on As (V) -containing water with concentration lower than 1mg/L, which can reach the drinking water standard (<10 mug/L).

Coexisting ion interference

Ca²⁺、Ma²⁺、SO₄ ^2–、SO₃ ^2–、NO^3–、HPO₃ ^2–、CO₃ ^2–Plasmas are widely present in natural or industrial waters and can interfere with the adsorption of as (v) by adsorbents by either occupying binding sites on the adsorbent surface by competition or by altering the surface charge of the adsorbent. Ca when the coexisting ion concentration was 0.1mmol²⁺、Ma²⁺、NO^3–、CO₃ ^2–Has no obvious influence on the adsorption effect, SO₄ ^2–、SO₃ ^2–、HPO₃ ^2–The adsorption effect is slightly reduced. This is mainly due to SO₄ ^2–、SO₃ ^2–、HPO₃ ^2–The structure is similar to that of As (V), and competitive adsorption is generated with As (V), so that the adsorption effect is slightly reduced. However, the decrease of the adsorption effect is within 10%, and the problem can be solved by increasing the addition amount of the adsorbent. Therefore, the anti-interference capacity of the adsorbing material is strong.

Comparative example 1

Preparation of spherical mesoporous silica by etching

And (2) preparing the amino and Fe (III) bifunctional spherical mesoporous silica adsorbing material, namely preparing mesoporous silica by etching instead of pseudomorphic transformation, wherein the rest steps are the same. The etching steps are as follows: 0.9g of spherical silica was mixed with 30mL of 0.15M NaOH solution uniformly and reacted at 750rpm for 24 hours. After the reaction is finished, centrifuging at 10000rpm for 10min, collecting the product, washing with ultrapure water for three times, and drying in an oven at 70 ℃ for 24 h.

The amino and Fe (III) dual-functional spherical mesoporous silica adsorbing material prepared by the method adsorbs 5mg/L of As (V) wastewater, and the removal rate is only 57.32 percent, which is far lower than that of the adsorbing material prepared by adopting pseudomorphic transformation. The reason is that the spherical mesoporous silica prepared by pseudomorphic transformation has more silicon hydroxyl on the surface, and is more beneficial to subsequent modification.

Comparative example 2

The other conditions are the same as the example 1, only 0.4g of APTES is added in the process of amino functionalization, and the amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material prepared by the method adsorbs 10mg/L of As (V) wastewater, so that the removal rate is only 75.55 percent and is far lower than that of the adsorbing material prepared by the example 1.

Comparative example 3

Under the same conditions as in example 1, when only the amino group was functionalized and the fe (iii) was not functionalized, the obtained amino group-functionalized spherical mesoporous silica adsorbed 10mg/L of as (v) wastewater, and the removal rate was almost 0, failing the experiment. A single amino functionalization is not sufficient for As (V) removal.

Claims

1. A preparation method of an amino and Fe (III) dual-functionalized spherical mesoporous silica adsorbing material is characterized by comprising the following steps: the method comprises the following steps:

step (1) preparation of spherical silica

Mixing absolute ethyl alcohol, ammonia water and tetraethoxysilane, reacting, and carrying out solid-liquid separation to obtain spherical silicon dioxide;

step (2) preparation of spherical mesoporous silica

Adding anhydrous ethanol, cetyl trimethyl ammonium bromide and H₂O, NaOH, mixing to obtain a mixed solution, adding the spherical silica obtained in the step (1) into the mixed solution, carrying out hydrothermal reaction, carrying out solid-liquid separation, and calcining the obtained solid phase to obtain the spherical mesoporous silica;

step (3) amino functionalization

Dispersing the spherical mesoporous silica obtained in the step (2) in an organic solvent, then adding aminopropyl trimethoxy silane, uniformly mixing, and carrying out solvothermal reaction to obtain amino functionalized spherical mesoporous silica;

step (4) Fe (III) functionalization

2. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (1), the volume ratio of the ethyl orthosilicate to the absolute ethyl alcohol is 5-10: 160;

in the step (1), the volume ratio of ammonia water to absolute ethyl alcohol is 10-20: 160;

in the step (1), NH is dissolved in the ammonia water₃The mass fraction of (A) is 25-28%.

In the step (1), the reaction is carried out at room temperature under stirring, the stirring rotation speed is 750-800 rpm, and the reaction time is 16-24 h;

in the step (1), the solid-liquid separation mode is centrifugation, the solid phase obtained after centrifugation is washed by absolute ethyl alcohol, dried to constant weight at 70-80 ℃, and ground into powder to obtain the spherical silicon dioxide.

3. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (2), the molar ratio of the spherical silica to CTAB is 1: 0.1-0.3; the molar ratio of the spherical silica to NaOH is 1: 0.3-0.6; spherical silica and H₂The molar ratio of O is 1: 500-1000.

in the step (2), the molar ratio of the spherical silica to the EtOH is 1: 50-100.

4. the preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (2), adding the spherical silicon dioxide obtained in the step (1) into the mixed solution, stirring for 20-30 min at room temperature, and then transferring to a hydrothermal reaction kettle for hydrothermal reaction;

in the step (2), the temperature of the hydrothermal reaction is 80-120 ℃, and the time is 20-30 h;

in the step (2), the calcination is carried out in an air atmosphere, the calcination temperature is 500-600 ℃, the time is 5-8 h, and the heating rate is 1-20 ℃/min.

5. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (3), the solid-liquid mass volume ratio of the spherical mesoporous silica to the organic solvent is 1 g: 80-120 mL;

in the step (3), the organic solvent is anhydrous toluene.

6. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (3), the addition amount of the aminopropyltrimethoxysilane is that the ratio of the aminopropyltrimethoxysilane to the spherical mesoporous silica is 5-10: 4;

in the step (3), the temperature of the solvothermal reaction is 100-130 ℃, and the time of the solvothermal reaction is 5-10 h.

7. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (4), the amino functionalized spherical mesoporous silica and FeCl₃The solid-liquid mass volume ratio of the solution is 0.1 g: 7-12 mL; the FeCl₃The concentration of the solution is 0.05-0.2M.

8. The preparation method of the amino group and Fe (III) -bifunctional spherical mesoporous silica adsorbent material according to claim 1, wherein:

in the step (4), the rotation speed of the stirring reaction is 750-800 rpm, and the time is 1-3 h;

in the step (4), the solid-liquid separation mode is centrifugation, the solid phase obtained after centrifugation is washed by absolute ethyl alcohol, and is dried in vacuum at 50-80 ℃ to constant weight, and is ground into powder to obtain the amino and Fe (III) dual-functionalized spherical mesoporous silica submicron composite material.

9. An amino and Fe (III) bifunctional spherical mesoporous silica adsorbent material prepared according to the preparation method of any one of claims 1 to 8.

10. Use of the amino group and Fe (III) bifunctional spherical mesoporous silica adsorbent material prepared according to any one of claims 1 to 8 for adsorbing As (V) in water.