AU2021102789A4

AU2021102789A4 - Method for preparing mesoporous silica nanospheres with dual-template approach

Info

Publication number: AU2021102789A4
Application number: AU2021102789A
Authority: AU
Inventors: Xiaonan FAN; Xia GUO
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2021-04-13
Filing date: 2021-05-24
Publication date: 2021-07-08
Anticipated expiration: 2029-05-24
Also published as: CN112919483A; CN112919483B

Abstract

OF THE DISCLOSURE The present disclosure relates to the technical field of mesoporous silica and provides a method for preparing mesoporous silica nanospheres with a dual-template approach. A cationic surface active agent (cetyl trimethyl ammonium bromide (CTAB) and/or cetyl trimethyl ammonium chloride (CTAC)) and a p-sulfonatocalix[n]arene (SC[n], n=4 or 8) used as templates and tetraethoxysilane used as a silicon source are subjected to a one-pot reaction to obtain silica nanospheres. The templates are then removed by calcination so that mesoporous silica nanospheres are obtained. The particle size of silica nanospheres can be controlled conveniently by controlling a ratio of the used cationic surface active agent to the used p-sulfonatocalix[n]arene, and the product can have a particle size adjustable within a wide range. Besides, the preparation method is simple with a high yield. The results of examples show that the mesoporous silica nanospheres having a particle size ranging from 50 to 160 nm can be prepared by using the method provided in the present disclosure. FIG.1 12

Description

METHOD FOR PREPARING MESOPOROUS SILICA NANOSPHERES WITH DUAL TEMPLATE APPROACH TECHNICAL FIELD

[01] The present disclosure relates to the technical field of mesoporous silica, and in particular, to a method for preparing mesoporous silica nanospheres with a dual-template approach.

BACKGROUNDART

[02] Mesoporous silica nanospheres are a nanometer material having a porous structure formed with organic molecules as templates. They have the advantages of high specific surface area, easy surface functionalization, good biocompatibility, high thermal stability, etc. and thus have a great application value in catalysis, molecular adsorption, drug delivery, etc. The Kresge team successfully synthesized an ordered mesoporous silica molecular sieve MCM-41 in 1992 for the first time, which set off a new wave of research on mesoporous materials.

[03] In the field of drug delivery, it is quite necessary to control the particle size of a carrier according to a drug to be delivered. At present, most studies on mesoporous material drug carriers are focused on MCM-41. However, due to a narrow controllable particle size range of the MCM-41, it is only possible to prepare mesoporous silica nanospheres having a particle size of 100 to 200 nm, but nearly impossible to prepare mesoporous silica nanospheres having a particle size of less than 100 nm. Consequently, the requirements of loading of various drug molecules on carries cannot be met.

[04] Patent CN105236417A discloses a preparation method of a particle size controllable spherical mesoporous silica, where the mesoporous silica is prepared from an amphiphilic polymer modified SiO 2 (SiO 2-PBA-PDMAEMA), cetyl trimethyl ammonium bromide (CTAB) and tetraethoxysilane by a self-assembly reaction and calcinationare with hydrochloric acid and ammonium hydroxide to regulate the pH value of the reaction liquid. The particle size of the mesoporous silica can be controlled by regulating the addition amount of the CTAB. However, only the mesoporous silica nanospheres having a particle size ranging from 25 to 90 nm can be prepared in the mentioned patent, and the silica nanospheres having a particle size of greater than 100 nm cannot be obtained. The controllable range of particle sizes is still narrow.

SUMMARY

[05] In view of the mentioned problems, the present disclosure provides a method for preparing mesoporous silica nanospheres with a dual-template approach, and the prepared mesoporous silica nanospheres have a wide controllable range of particle sizes. The mesoporous silica nanospheres having a particle size ranging from 50 to 160 nm can be prepared by using the method provided in the present disclosure.

[06] To achieve the objective of the present disclosure, the present disclosure provides the following technical solution.

[07] A method for preparing mesoporous silica nanospheres with a dual-template approach includes the following steps:

[08] mixing a cationic surface active agent, a p-sulfonatocalix[n]arene, tetraethoxysilane and an alkaline substance with water to react, to obtain a product liquid;

[09] subjecting the product liquid to solid-liquid separation, washing and drying a resulting solid product, and then subjecting the solid product to calcination, to obtain mesoporous silica nanospheres;

[10] where the cationic surface active agent includes cetyltrimethyl ammonium bromide and/or cetyltrimethyl ammonium chloride; the p-sulfonatocalix[n]arene includes p-sulfonatocalix[4]arene and/or p-sulfonatocalix[8]arene; and

[11] a molar ratio of the tetraethoxysilane, the cationic surface active agent and the p sulfonatocalix[n]arene may be 1: (0.055 to 0.065):(0 to 0.0029).

[12] Preferably, in the product liquid, a concentration of the cationic surface active agent may be 21 to 63 mmol/L and a concentration of the p-sulfonatocalix[n]arene may be 0.0525 to 2.1 mmol/L.

[13] Preferably, a ratio of positive charges of positive ions in the cationic surface active agent to negative charges of the p-sulfonatocalix[n]arene may be (5 to 200):1.

[14] Preferably, the alkaline substance includes one or more from the group consisting of triethanolamine, triethylamine and ammonium hydroxide.

[15] Preferably, a molar ratio of the tetraethoxysilane, the alkaline substance and the water may be 1:(0.020 to 0.030):(75 to 85); and when the alkaline substance is ammonium hydroxide, a molar weight of the ammonium hydroxide may be based on a molar weight of a solute.

[16] Preferably, the reaction may occur at 60 to 90°C for 1 to 3 hours.

[17] Preferably, the drying may be conducted at 70 to 90°C for 1 to 3 hours.

[18] Preferably, the calcination may be conducted at 400 to 700°C for 3 to 7 hours.

[19] Preferably, the mesoporous silica nanospheres may have a particle size of 50 to 160 nm.

[20] The present disclosure provides a method for preparing mesoporous silica nanospheres with a dual-template approach. According to this method, a cationic surface active agent (cetyl trimethyl ammonium bromide (CTAB) and/or cetyl trimethyl ammonium chloride (CTAC)) and a p sulfonatocalix[n]arene (SC[n], n=4 or 8) used as templates and tetraethoxysilane used as a silicon source are subjected to a one-pot reaction to obtain silica nanospheres; and the templates are then removed by calcination so that mesoporous silica nanospheres are obtained, where a molar ratio of the tetraethoxysilane, the cationic surface active agent and the p-sulfonatocalix[n]arene is 1: (0.055 to 0.065):(0 to 0.0029). According to the present disclosure, when the p-sulfonatocalix[n]arene is not used, i.e., when a cationic surface active agent is used as a single template to prepare mesoporous silica nanospheres, a silicate oligomer generated from the hydrolyzation of tetraethoxysilane is synergistically self-assembled with the cationic surface active agent (CTAB and/or CTAC) to form an aggregate. With the aggregate as a template, the silicate oligomer nucleates and slowly grows to form silica nanospheres. In this case, the obtained mesoporous silica nanospheres have a small particle size. When the p-sulfonatocalix[n]arene is used in a particular amount, the p sulfonatocalix[n]arene and the cationic surface active agent (CTAB and/or CTAC) form a supramolecular amphiphile which is self-assembled with a silicate oligomer to form an aggregate. A hydroxyl group exposed from the lower margin of the p-sulfonatocalix[n]arene may form a hydrogen bond with a silicon hydroxyl group. With the deposition of a silicate generated from induced hydrolyzation, the nucleation and growth rate of silica is increased and the particle size of the obtained mesoporous silica nanospheres is thus increased. Besides, as the addition amount of the p sulfonatocalix[n]arene is increased to gradually approach a stoichiometric ratio of the cationic surface active agent (CTAB and/or CTAC) and the p-sulfonatocalix[n]arene, the thus formed supramolecular amphiphile aggregate may have an increased volume and reduced apparent charge density, resulting in an increased pore size of the mesoporous silica nanospheres. Since SC[8] has a larger hydrophobic cavity than SC[4], the resulting mesoporous silica nanospheres may have a larger pore size.

[21] In the present disclosure, a ratio of positive charges of positive ions in the cationic surface active agent to negative charges of the p-sulfonatocalix[n]arene (denoted as CTA+/SC[n]n-) can be controlled by controlling the addition amounts of the cationic surface active agent and the p sulfonatocalix[n]arene. When the p-sulfonatocalix[n]arene is not used, the resulting mesoporous silica nanospheres may have the minimum particle size and the maximum specific surface area. When the p-sulfonatocalix[n]arene is used in a particular amount, as the ratio of the charges is gradually reduced (i.e., as the addition amount of the p-sulfonatocalix[n]arene is gradually increased), the resulting mesoporous silica nanospheres may have a gradually increased particle size, a gradually increased pore size and gradually enhanced surface roughness. According to the present disclosure, the particle size of the mesoporous silica nanospheres can be controlled conveniently by controlling the addition amount of the p-sulfonatocalix[n]arene.

[22] According to the present disclosure, the mesoporous silica nanospheres which are dispersed uniformly and are stable in structure and controllable in particle size and pore size can be obtained by combining the cationic surface active agent and the p-sulfonatocalix[n]arene in different ratios. Moreover, the preparation method provided in the present disclosure has the advantages of simple steps, and high yield and wide controllable particle size range of the resulting products. The results of examples show that the mesoporous silica nanospheres having a particle size ranging from 50 to 160 nm can be prepared by using the method provided in the present disclosure and the resulting mesoporous silica nanospheres have highly ordered internal pores.

BRIEF DESCRIPTION OF THE DRAWINGS

[23] FIG. 1 shows transmission electron microscope images of resulting mesoporous silica nanospheres according to examples 1 to 3 of the present disclosure.

[24] FIG. 2 is a diagram of particle size distribution of resulting mesoporous silica nanospheres according to example 1 of the present disclosure.

[25] FIG. 3 is a diagram of particle size distribution of resulting mesoporous silica nanospheres according to example 2 of the present disclosure.

[26] FIG. 4 is a diagram of particle size distribution of resulting mesoporous silica nanospheres according to example 3 of the present disclosure.

[27] FIG. 5 shows transmission electron microscope images of resulting mesoporous silica nanospheres according to examples 1, 4 and 5 of the present disclosure.

[28] FIG. 6 is a diagram of particle size distribution of resulting mesoporous silica nanospheres according to example 4 of the present disclosure.

[29] FIG. 7 is a diagram of particle size distribution of resulting mesoporous silica nanospheres according to example 5 of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[30] The present disclosure provides a method for preparing mesoporous silica nanospheres with a dual-template approach, including the following steps:

[31] mix a cationic surface active agent, a p-sulfonatocalix[n]arene, tetraethoxysilane and an alkaline substance with water to react, to obtain a product liquid;

[32] subject the product liquid to solid-liquid separation, wash and dry a resulting solid product, and then subject the solid product to calcination, to obtain mesoporous silica nanospheres.

[33] According to the present disclosure, a cationic surface active agent, a p sulfonatocalix[n]arene, tetraethoxysilane and an alkaline substance are mixed with water to react, to obtain a product liquid. In the present disclosure, the cationic surface active agent includes cetyltrimethyl ammonium bromide (CTAB) and/or cetyltrimethyl ammonium chloride (CTAC); the p-sulfonatocalix[n]arene includes p-sulfonatocalix[4]arene (SC[4]) and/or p-sulfonatocalix[8]arene (SC[8]); and a molar ratio of the tetraethoxysilane, the cationic surface active agent and the p sulfonatocalix[n]arene is 1: (0.055 to 0.065):(0 to 0.0029), preferably 1: (0.058 to 0.062):(0.0001 to 0.002), and further preferably 1: 0.06: (0.001 to 0.002). Specifically, when the p sulfonatocalix[n]arene is SC[8], the molar ratio of the tetraethoxysilane, the cationic surface active agent and SC[8] is further preferably 1: (0.055 to 0.065):(0 to 0.0011).

[34] In the present disclosure, in the product liquid, a concentration of the cationic surface active agent is preferably 21 to 63 mmol/L, more preferably 25 to 60 mmol/L, while a concentration of the p-sulfonatocalix[n]arene is preferably 0.0525 to 2.1 mmol/L, more preferably 0.06 to 1.5 mmol/L. In a specific embodiment of the present disclosure, the concentration of each of the cationic surface active agent and the p-sulfonatocalix[n]arene is calculated as a ratio of the molar weight of the cationic surface active agent (or the p-sulfonatocalix[n]arene) to the volume of the water in the product liquid, and the addition amounts of other substances are neglected. In the present disclosure, a ratio of positive charges of positive ions in the cationic surface active agent to negative charges of the p-sulfonatocalix[n]arene (denoted as CTA+/SC[n]"-) is preferably (5 to 200):1, more preferably (10 to 180):1, and further preferably (50 to 150):1. According to the present disclosure, CTA*/SC[n]" can be controlled by regulating the molar ratio of the cationic surface active agent and the p sulfonatocalix[n]arene, and then the particle size of the mesoporous silica nanospheres can be controlled. When a larger amount of p-sulfonatocalix[n]arene is used, the resulting mesoporous silica nanospheres may have a larger particle size, a larger specific surface area, a larger pore size and greater surface roughness.

[35] In the present disclosure, the alkaline substance includes one or more from the group consisting of triethanolamine, triethylamine and ammonium hydroxide. A molar ratio of the tetraethoxysilane, the alkaline substance and the water is preferably 1:(0.020 to 0.030):(75 to 85), and more preferably 1:(0.022 to 0.025):(78 to 82). When the alkaline substance is ammonium hydroxide, a molar weight of the ammonium hydroxide is based on a molar weight of a solute. According to the present disclosure, the pH value of the reaction liquid is regulated to a range of 7.5 to 10 by using the alkaline substance, thus promoting hydrolyzation of the tetraethoxysilane.

[36] In the present disclosure, the reaction preferably occurs at 60 to 90°C, more preferably 80°C, preferably for 1 to 3 hours, more preferably 2 hours. The reaction preferably occurs while stirring, and a rate of stirring is preferably 500 to 1500 rpm, more preferably 1200 rpm. In a specific embodiment of the present disclosure, it is preferred that a cationic surface active agent, a p sulfonatocalix[n]arene, an alkaline substance and deionized water are mixed first and stirred under the conditions of 60 to 90°C and 500 to 1500 rpm for 1 h to obtain a pre-mixed liquid, followed by rapidly adding tetraethoxysilane to the pre-mixed liquid to react.

[37] According to the present disclosure, after the reaction is finished, the obtained product liquid is subjected to solid-liquid separation, and the resulting solid product is washed and dried and then subjected to calcination, to obtain mesoporous silica nanospheres (MSNs). In the present disclosure, the solid-liquid separation is preferably centrifugal separation which is preferably conducted at a revolving speed of 10000 rpm; the washing is preferably conducted by using ethanol, preferably for three times; and the drying is preferably conducted at 70 to 90°C, more preferably 80°C, preferably for 1 to 3 hours, more preferably 2 hours.

[38] In the present disclosure, the calcination is preferably conducted at 400 to 700°C, more preferably 550 to 600°C, preferably for 3 to 7 hours, more preferably 5 to 6 hours. A rate of rise of the temperature to the temperature of the calcination is preferably 2°C/min. The calcination is preferably conducted in a muffle furnace. According to the present disclosure, the templates in the solid product are removed by the calcination, thereby forming mesopores in the silica nanospheres and obtaining the mesoporous silica nanospheres.

[39] In the present disclosure, the mesoporous silica nanospheres preferably have a particle size of 50 to 160 nm, more preferably 60 to 150 nm. The mesoporous silica nanospheres have a pore size of mesopores (according to the IUPAC classification standards, pores having a pore size ranging from 2.0 to 50 nm are called mesopores). In a specific embodiment of the present disclosure, when the molar ratio of the tetraethoxysilane, the cationic surface active agent and SC[4] is 1:(0.055 to 0.065):(0 to 0.0029), the resulting mesoporous silica nanospheres have a preferred particle size of 52 to 160 nm, a preferred specific surface area of 286 to 85 m 2/g, and a preferred pore size of 2.9 to 3.3 nm. When the tetraethoxysilane, the cationic surface active agent and SC[4] is 1:(0.055 to 0.065):(0 to 0.0011), the resulting mesoporous silica nanospheres have a preferred particle size of52 to 155nm, a preferred specific surface area of 286 to 109 m2 /g, and a preferred pore size of 2.9 to 3.5 nm. When only CTAB is used as the template, the resulting mesoporous silica nanospheres have a particle size of 52+5 nm, a specific surface area of 286 m 2/g, and a pore size of 2.9 nm.

[40] The technical solution in the present disclosure will be clearly and completely described below with reference to examples of the present disclosure.

[41] Example 1

[42] (1) 0.38 g of CTAB and 0.068 g of triethanolamine were mixed with 25 mL of deionized water and stirred at 1200 rpm for 1 h at 80°C to obtain a pre-mixed liquid. 4 mL of tetraethoxysilane was then rapidly added to the pre-mixed liquid and stirred at 1200 rpm for 2 h at 80°C to obtain a product liquid. In the product liquid of all the components, the concentration of CTAB was 42 mmol/L.

[43] (2) The obtained product liquid was subjected to centrifugal separation at 10000 rpm, and the resulting solid product was washed by using ethanol for 3 times. A white product obtained from the washing was dried in a drying oven at 80°C for 2 h. The dried product was then put into a muffle furnace for calcination at 550°C (the temperature was increased to 550°C at a rate of 2°C) for 5 h. After being cooled naturally, the mesoporous silica nanospheres were obtained, with a yield of 1.01

g.

[44] Example 2

[45] As in example 1, with the difference that 0.0097 g of SC[4] was added in step (1). In the product liquid, the concentration of CTAB was 42 mmol/L, while the concentration of SC[4] was 0.52 mmol/L. The yield of the resulting mesoporous silica nanospheres was 1.03 g.

[46] Example 3

[47] As in example 2, with the difference that the addition amount of SC[4] was changed to 0.0391 g. In the product liquid, the concentration of CTAB was 42 mmol/L, while the concentration of SC[4] was 2.1 mmol/L. The yield of the resulting mesoporous silica nanospheres was 0.58 g.

[48] The prepared mesoporous silica nanospheres in examples 1to 3 were tested by using a transmission electron microscope, with the results as shown in FIG. 1, with (a) and (b) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 1, (c) and (d) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 2, (e) and (f) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 3. The scale for (a), (c) and (e) was 200 nm, while the scale for (b), (d) and (f) was 100 nm. As can be seen from FIG. 1, the resulting mesoporous silica nanospheres in examples 1 to 3 were uniformly spherical, and the resulting mesoporous silica nanospheres in example 1 had the minimum particle size. In examples 2 and 3, as the addition amount of SC[4] was gradually increased, the particle size of the resulting mesoporous silica nanospheres was gradually increased. In addition, an ordered mesoporous lattice structure can be observed in FIG. 1 (a) to FIG. 1 (f), indicating that the pores of the resulting mesoporous silica nanospheres were mesopores.

[49] The particle sizes of the mesoporous silica nanospheres prepared in examples 1 to 3 were tested, with the results as shown in FIG. 2 to FIG. 4, which are diagrams of particle size distributions of the resulting mesoporous silica nanospheres in examples 1to 3. The test results in FIG. 2 to FIG. 4 show that the resulting mesoporous silica nanospheres in example 1 had a particle size of 525 nm, while the resulting mesoporous silica nanospheres in example 2 had a particle size of 72+5 nm and the resulting mesoporous silica nanospheres in example 3 had a particle size of 16010 nm.

[50] In addition, the specific surface areas and pore sizes of the resulting mesoporous silica nanospheres in examples 1 and 3 were tested, with the results showing that: the resulting mesoporous silica nanospheres in example 1 had a specific surface area of 286 m 2/g and a pore size of 2.9 nm, while the resulting mesoporous silica nanospheres in example 3 had a specific surface area of 85 m2/g and a pore size of 3.3 nm.

[51] Example 4

[52] As in example 2, with the difference that SC[4] was replaced by SC[8] and 0.0098 g of SC[8] was added. In the product liquid, the concentration of CTAB was 42 mmol/L, while the concentration of SC[8] was 0.2625 mmol/L. The yield of the resulting mesoporous silica nanospheres was 0.98 g.

[53] Example 5

[54] As in example 4, with the difference that the addition amount of the SC[8] was changed to 0.028 g. In the product liquid, the concentration of CTAB was 42 mmol/L, while the concentration of SC[8] was 0.75 mmol/L. The yield of the resulting mesoporous silica nanospheres was 0.78 g.

[55] The prepared mesoporous silica nanospheres in examples 4 and 5 were tested by using a transmission electron microscope, with the transmission electron microscope images as shown in FIG. 5 together with that of the resulting mesoporous silica nanospheres in example 1, with (a) and (b) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 1, (c) and (d) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 4, (e) and (f) showing the transmission electron microscope images of the resulting mesoporous silica nanospheres in example 5. The scale for (a), (c) and (e) was 200 nm, while the scale for (b), (d) and (f) was 100 nm. As can be seen from FIG. 5, after SC[8] was added, as the addition amount of SC[8] was gradually increased, the particle size of the resulting mesoporous silica nanospheres was gradually increased. In addition, an ordered mesoporous lattice structure can be observed in FIG. 5 (a) to FIG. 5 (f), indicating that the pores of the resulting mesoporous silica nanospheres were mesopores.

[56] The particle size distributions of the mesoporous silica nanospheres prepared in examples 4 and 5 were tested, with the results as shown in FIG 6 and FIG 7, which are diagrams of particle size distributions of the resulting mesoporous silica nanospheres in examples 4 and 5. The test results in FIG. 4 and FIG. 5 show that the resulting mesoporous silica nanospheres in example 4 had a particle size of 80+5 nm, while the resulting mesoporous silica nanospheres in example 5 had a particle size of 155+10 nm.

[57] In addition, the specific surface area and pore size of the resulting mesoporous silica nanospheres in example 5 were tested, with the results showing that: the resulting mesoporous silica nanospheres in example 5 had a specific surface area of 109 m2/g and a pore size of 3.5 nm.

[58] The yields of the resulting mesoporous silica nanospheres in examples 1 to 5 were calculated, with the results summarized in table 1. 4 mL of tetraethoxysilane was added in examples 1 to 5, and a theoretical yield of the mesoporous silica nanospheres can be calculated according to a hydrolyzation equation of the tetraethoxysilane to be 1.07, and a production rate was equal to an actual yield/1.07*100%.

[59] Table 1 Yields of Resulting Mesoporous Silica Nanospheres in Examples 1 to 5 Serial No. Concentration of Template MSNs Yield (g) MSNs Production Rate(%)

Example 1 [CTAB] = 42 mM 1.01 94.39

Example 2 [CTAB] = 42 mM, SC[4] = 0.52 mM 1.03 96.26

Example 3 [CTAB] = 42 mM, SC[4] = 2.1 mM 0.58 54.2

Example 4 [CTAB] = 42 mM, SC[8] = 0.2625 mM 0.98 91.59

Example 5 [CTAB] = 42 mM, SC[8] = 0.75 mM 0.78 72.90

[60] As can be seen from data in table 1, the production rate of the mesoporous silica nanospheres prepared by using the method provided in the present disclosure can be up to 96.26%. The production rate in example 3 was relatively low (which could be 54.2%) because it may decrease due to enhanced electronegativity of the system as the addition amount of the p-sulfonatocalix[n]arene was increased to approach a stoichiometric ratio.

[61] As can be seen from the results of the examples, the cationic surface active agent (CTAB and/or CTAC) and SC[n] were used as dual templates in the present disclosure, and the particle size of the resulting mesoporous silica nanospheres can be controlled conveniently by controlling the ratio of the two templates. The product can have a particle size adjustable within a wide range. Besides, the preparation method is simple with a high yield.

[62] The above descriptions are merely preferred embodiments of the present disclosure. It should be noted that a person of ordinary skill in the art may make several improvements and modifications without departing from the principle of the present disclosure, and such improvements and modifications should be deemed as falling within the protection scope of the present disclosure.

Claims

WHAT IS CLAIMED IS:

1. A method for preparing mesoporous silica nanospheres with a dual-template approach, comprising the following steps:

mixing a cationic surface active agent, a p-sulfonatocalix[n]arene, tetraethoxysilane and an alkaline substance with water to react, to obtain a product liquid;

subjecting the product liquid to solid-liquid separation, washing and drying a resulting solid product, and then subjecting the solid product to calcination, to obtain mesoporous silica nanospheres;

wherein the cationic surface active agent comprises cetyltrimethyl ammonium bromide and/or cetyltrimethyl ammonium chloride; the p-sulfonatocalix[n]arene comprises p sulfonatocalix[4]arene and/or p-sulfonatocalix[8]arene; and

a molar ratio of the tetraethoxysilane, the cationic surface active agent and the p sulfonatocalix[n]arene is 1: (0.055 to 0.065):(0 to 0.0029).

2. The method according to claim 1, wherein in the product liquid, a concentration of the cationic surface active agent is 21 to 63 mmol/L and a concentration of the p sulfonatocalix[n]arene is 0.0525 to 2.1 mmol/L;

wherein a ratio of positive charges of positive ions in the cationic surface active agent to negative charges of the p-sulfonatocalix[n]arene is (5 to 200):1.

3. The method according to claim 1, wherein the alkaline substance comprises one or more from the group consisting of triethanolamine, triethylamine and ammonium hydroxide;

wherein a molar ratio of the tetraethoxysilane, the alkaline substance and the water is 1:(0.020 to 0.030):(75 to 85); and when the alkaline substance is ammonium hydroxide, a molar weight of the ammonium hydroxide is based on a molar weight of a solute.

4. The method according to claim 1, wherein the reaction is conducted at 60 to 90°C for 1 to 3 hours; wherein the drying is conducted at 70 to 90°C for 1 to 3 hours; wherein the calcination is conducted at 400 to 700 °C for 3 to 7 hours.

5. The method according to claim 1, wherein the mesoporous silica nanospheres have a particle size of 50 to 160 nm.

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FIG. 7