CN116571206B

CN116571206B - Aluminum-containing silicon-based adsorbent, preparation method thereof and application of adsorbent in removing glyphosate in water

Info

Publication number: CN116571206B
Application number: CN202310472082.9A
Authority: CN
Inventors: 吕仁亮; 陈柳; 韩庆文; 朱君燕; 周若瑜
Original assignee: Hubei Three Gorges Laboratory
Current assignee: Hubei Three Gorges Laboratory
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2024-10-15
Anticipated expiration: 2043-04-27
Also published as: CN116571206A

Abstract

The invention relates to a preparation method of an aluminum-containing silicon-based adsorbent and application of the adsorbent in treating glyphosate wastewater, wherein the aluminum-containing silicon-based adsorbent takes amorphous mesoporous silica as a framework. The aluminum-containing silicon-based adsorbent provided by the invention is nontoxic, does not produce secondary pollution to water, has moderate specific surface area, pore volume and pore diameter, has large adsorption capacity of glyphosate, and has wide application prospect in the field of treating glyphosate wastewater.

Description

Aluminum-containing silicon-based adsorbent, preparation method thereof and application of adsorbent in removing glyphosate in water

Technical Field

The invention belongs to the technical field of adsorption treatment of water, wastewater or sewage, and particularly relates to an aluminum-silicon-based adsorbent, a preparation method thereof and application of the adsorbent in removing glyphosate in water.

Background

Glyphosate (Glyphosate) is a contaminant present in natural bodies of water. This organophosphorus herbicide is widely used in agricultural production, but is potentially carcinogenic in itself and in its metabolites. Because of excessive use and water solubility of glyphosate, the substances can permeate water along with soil and enter water bodies to destroy ecological environment. The European Union drinking water quality directive (European DRINKING WATER DIRECTIVE) prescribes that the content of glyphosate in safe surface waters should not exceed 0.1 mug/L. Therefore, the method for simply, conveniently and efficiently enriching and removing the glyphosate in the water body is an important measure for treating the water pollution.

At present, common treatment methods in the aspect of glyphosate pollution treatment include a biological method, a physical method, a chemical precipitation method, an adsorption method and the like. Adsorption has become a unique technology in the environmental treatment process, and has been widely applied to the treatment of wastewater and waste gas. Adsorption is one of the effective methods for treating industrial wastewater, and is a method for purifying wastewater by adsorbing one or more contaminants in wastewater with an adsorbent to recover or remove them. At present, the adsorption method is applied to the treatment of the wastewater from the production of the glyphosate, and a better effect is obtained.

The adsorbent used for treating the wastewater in the production of the glyphosate comprises mesoporous silica, active carbon, adsorption resin and the like. Although the activated carbon has the advantages of low cost and capability of adsorbing various pollutants, the activated carbon has poor adsorption selectivity and low adsorption capacity of glyphosate. The adsorption resin can effectively adsorb various compounds with different chemical properties, and has good selectivity to organic matters, excellent performance and stable physicochemical properties. However, resin adsorbents are generally not strong in rigidity and easy to break, and raw materials such as pore-forming agents or solvents used in the preparation process remain due to incomplete removal, so that secondary pollution is easily caused. The mesoporous silica material has the characteristics of an excellent adsorption material: the order of the pore canal structure; pore size distribution singleness and controllability, mesoporous shape diversity, so that the catalyst has extremely important functions in the fields of adsorption separation, environmental protection and the like. The pure silicon-based mesoporous material has low chemical activity and poor adsorption performance on glyphosate. The common method for solving the problem is to modify mesoporous silica to improve the surface activity, the adsorption performance and the selectivity and expand the application range.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an aluminum-containing silicon-based adsorbent, a preparation method thereof and application of the adsorbent in removing glyphosate in water, and the aluminum-containing silicon-based adsorbent has the advantages of large adsorption capacity for glyphosate, good selectivity and good application prospect in the aspect of glyphosate wastewater treatment.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

An aluminum-containing silicon-based adsorbent takes amorphous mesoporous silica as a framework, metal element aluminum is doped after the amorphous mesoporous silica is synthesized, and the metal element aluminum is uniformly distributed on the surface and inside the framework.

According to the scheme, the average pore diameter of the amorphous mesoporous silica is 6-20 nm, the pore volume is 0.7-1.3 cm ³/g, and the specific surface area is 350-500 m ²/g.

The invention also comprises a preparation method of the aluminum-containing silicon-based adsorbent, which comprises the following specific steps:

1) Preparing hydroxyethyl cellulose solution and sodium metasilicate solution with a certain concentration ratio, adding the sodium metasilicate solution into the stirred hydroxyethyl cellulose solution at 88-92 ℃, and stirring at a constant temperature. The pH of the system is adjusted to be slightly acidic by an acid solution. After the reaction is fully carried out for 1 to 3 hours, the reaction is carried out for 16 to 24 hours at 25 ℃. Stopping stirring, and aging for 16-20 hr. Adding an aluminum-containing solution under stirring, regulating the pH of the solution to 4-6 by using a sodium hydroxide solution, and stirring for 0.5-2h to obtain a reaction solution;

2) And (3) placing the reaction liquid obtained in the step (1) into a hydrothermal reaction kettle, centrifuging, washing, drying, grinding and roasting a solid product after the hydrothermal crystallization reaction to obtain the solid adsorbent, wherein x represents the molar ratio of Al to Si, and the solid adsorbent is named as Al (x) -HECMS.

According to the scheme, the mass concentration ratio of the hydroxyethyl cellulose solution to the sodium metasilicate solution in the step 1) is 1:25-30.

According to the scheme, the dropping speed of the sodium metasilicate solution in the step 1) is 2.5-5mL/min.

According to the scheme, the heating and stirring temperature in the step 1) is 88-92 ℃.

According to the scheme, in the step 1), the aluminum source is one of AlCl ₃·8H₂O、Al₂(SO₄)₃、Al₂Na₂O₄, the concentration of the aluminum-containing solution is 0.01-0.2 mol/L, and the molar ratio of aluminum element in the aluminum source solution to silicon element in the sodium metasilicate aqueous solution is 0.1-1:1.

According to the scheme, the stirring time is 30-60min after the aluminum source solution is added in the step 1). Stirring to make the aluminum ion distributed more uniformly in the gel solution, and not easy to agglomerate.

According to the scheme, the acid solution in the step 1) is 6.4-7.5% hydrochloric acid solution.

Following the above protocol, the concentration of the sodium hydroxide solution in step 1) is 1-2 mol/L.

According to the scheme, the hydrothermal crystallization reaction temperature in the step 2) is 85-95 ℃, and the hydrothermal crystallization reaction time is 16-40h.

According to the scheme, the roasting process conditions in the step 2) are as follows: heating to 450-550 ℃ at the room temperature at the speed of 2-5 ℃/min, and preserving heat for 6-10h. And removing the surfactant hydroxyethyl cellulose by increasing the temperature in the roasting process, so as to form a mesoporous structure.

The invention also comprises application of the aluminum-containing silicon-based adsorbent in removing glyphosate in water.

The invention firstly adopts a sol-gel method to prepare mesoporous silica, and then utilizes a hydrothermal crystallization process to enable aluminum atoms to replace silicon atoms in a mesoporous silica framework in situ, thereby forming an Al-O-Si structure with uniform distribution. Since most aluminum compounds vary greatly in chemical behavior under acidic and basic conditions, attention must be paid to the ph of the synthesis system during aluminum doping. According to the invention, after the pH value is regulated in the first step, a mesoporous silica (HECMS) skeleton structure is formed by sol, after an aluminum source is added and fully and uniformly stirred, the pH value of a solution changes, the acidity of the solution is enhanced, metal aluminum exists in the form of Al ³⁺, the pH value of a system is regulated to 4-6 by alkali liquor in the second step, al ³⁺ is converted into the form of Al (OH) ₃, and the aluminum is combined with a silicon skeleton through the action of hydrothermal crystallization to form Al-O-Si bonds, so that the aluminum is effectively doped into the wall of the mesoporous silica hole and the surface of the hole wall. Due to the doping of the metal aluminum, the adsorption capacity of the mesoporous material to the glyphosate is improved by utilizing the coordination effect of the metal aluminum.

The invention has the beneficial effects that: 1. the aluminum-containing silicon-based adsorbent provided by the invention is nontoxic, does not produce secondary pollution to water, has moderate specific surface area, pore volume and pore diameter, and has large glyphosate adsorption capacity, and has wide application prospect in the field of pesticide-containing wastewater treatment. 2. The preparation method has simple steps, low-cost and easily-obtained raw materials, and is suitable for large-scale production.

Drawings

Fig. 1 is a graph showing the nitrogen adsorption/desorption isotherm and pore size distribution of the adsorbent (aluminum-silicon molar ratio=0.3:1) prepared in example 1 of the present invention.

Fig. 2 is a nitrogen adsorption/desorption isotherm and pore size distribution plot of the adsorbent prepared in example 2 (aluminum silicon molar ratio=0.2:1).

Fig. 3 is a nitrogen adsorption/desorption isotherm and pore size distribution plot of the adsorbent prepared in example 3 (aluminum silicon molar ratio=0.1:1).

FIG. 4 is a graph of the equilibrium adsorption performance of the adsorbent prepared in example 1 at 30℃for glyphosate solutions of different pH values.

FIG. 5 is a graph of equilibrium adsorption performance of the aluminum-doped adsorbent prepared in example 1 at 30℃for glyphosate solutions of different initial concentrations.

FIG. 6 is a wide-angle X-ray diffraction pattern of the adsorbent prepared in example 1.

FIG. 7 is a graph showing the adsorption/desorption isotherm and pore size distribution of HECMS of comparative example 1.

FIG. 8 is a graph showing the adsorption/desorption isotherm and pore size distribution of nitrogen of Zr-HECMS prepared in comparative example 2.

FIG. 9 is a graph of equilibrium adsorption performance of Fe-HECMS prepared in comparative example 3 at 30deg.C for glyphosate solutions of different pH values.

Detailed Description

The present invention will be described in further detail below with reference to the accompanying drawings, so that those skilled in the art can better understand the technical scheme of the present invention.

Example 1

An aluminum-containing silicon-based adsorbent (aluminum-silicon molar ratio=0.3:1) is prepared by the following steps:

1) Adding 3g of hydroxyethyl cellulose into 300mL of water, heating to 90 ℃ and stirring for dissolution to obtain a hydroxyethyl cellulose solution, dissolving 14.21g of Na ₂SiO₃·9H₂ O into 50mL of water to obtain a sodium metasilicate solution, then dropwise adding the sodium metasilicate solution into the hydroxyethyl cellulose solution, keeping the temperature unchanged during the dropwise adding process, stirring for 30min, regulating the pH value of the system to 5-6 by using 2mol/L of hydrochloric acid solution, stirring for 2h, cooling to 25 ℃, continuing stirring for 24h, stopping stirring, standing for ageing for 20 h, adding 10 mL of 1.5 mol/L of aluminum source solution (AlCl ₃·6H₂ O is dissolved in water to obtain a solution), stirring for 30min, and regulating the pH value of the system to 5 by using 2mol/L of NaOH solution to obtain a reaction solution;

2) And (3) placing the reaction solution in a hydrothermal reaction kettle, performing hydrothermal crystallization reaction at 100 ℃ for 24 h, performing centrifugal washing for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min each time, then drying at 100 ℃ for 24: 24 h, grinding the obtained solid, finally roasting the solid, and heating to 550 ℃ from room temperature at a speed of 2 ℃/min to calcine for 6h to obtain the aluminum-containing silicon-based adsorbent Al (0.3) -HECMS.

Fig. 1 shows the nitrogen adsorption and desorption isotherm and the pore size distribution diagram of the aluminum-containing silicon-based adsorbent Al (0.3) -HECMS prepared in example 1, and the nitrogen adsorption and desorption curve of the aluminum-doped HECMS material prepared in example 1 is an IV-type isotherm, which is an adsorption characteristic curve of a mesoporous material, and illustrates that the material has a mesoporous structure. And the nitrogen adsorption and desorption curve shows an H2-type hysteresis loop, indicating that the pore structure is similar to an ink bottle. According to the physical adsorption and desorption data of nitrogen, the specific surface area of the material is 428.57m ²/g, the pore volume is 0.44cm ³/g, the average pore diameter is 4.17 nm, and the material has good mesoporous material characteristics.

Example 2

An aluminum-containing silicon-based adsorbent (aluminum-silicon molar ratio=0.2:1) is prepared by the following steps:

1) Adding 3g of hydroxyethyl cellulose into 300mL of water, heating to 90 ℃ and stirring for dissolution to obtain a hydroxyethyl cellulose solution, dissolving 14.21g of Na ₂SiO₃·9H₂ O into 50 mL of water to obtain a sodium metasilicate solution, then dropwise adding the sodium metasilicate solution into the hydroxyethyl cellulose solution, keeping the temperature unchanged during the dropwise adding process, stirring for 30 min, regulating the pH value of the system to 5-6 by using 2mol/L hydrochloric acid solution, stirring for 2h, cooling to 25 ℃, continuing stirring for 24 h, stopping stirring, standing for ageing for 20 h, adding 10mL of 1mol/L aluminum source solution (AlCl ₃·6H₂ O is dissolved in water), stirring for 30 min, and regulating the pH value of the system to 5 by using 2mol/L NaOH solution to obtain a reaction solution;

2) And (3) placing the reaction solution in a hydrothermal reaction kettle, performing hydrothermal crystallization reaction at 100 ℃ for 24 h, performing centrifugal washing for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min each time, then drying at 100 ℃ for 24: 24 h, grinding the obtained solid, finally roasting the solid, and heating to 550 ℃ from room temperature at a speed of 2 ℃/min to calcine for 6h to obtain the aluminum-containing silicon-based adsorbent Al (0.2) -HECMS.

FIG. 2 is a graph showing the adsorption/desorption isotherms and pore size distribution of nitrogen containing silica-based adsorbent Al (0.2) -HECMS prepared in example 2. According to the data of physical adsorption and desorption of nitrogen, the specific surface area of the aluminum-containing silicon-based adsorbent prepared in the embodiment is 456.96m ²/g, the pore volume is 0.59cm ³/g, and the average pore diameter is 4.97 nm.

Example 3

An aluminum-containing silicon-based adsorbent (aluminum-silicon molar ratio=0.1:1), which is prepared by the following steps:

1) Adding 3g of hydroxyethyl cellulose into 300mL of water, heating to 90 ℃ and stirring for dissolution to obtain a hydroxyethyl cellulose solution, dissolving 14.21g of Na ₂SiO₃·9H₂ O into 50mL of water to obtain a sodium metasilicate solution, then dropwise adding the sodium metasilicate solution into the hydroxyethyl cellulose solution, keeping the temperature unchanged during the dropwise adding process, stirring for 30min, regulating the pH value of the system to 5-6 by using 2mol/L hydrochloric acid solution, stirring for 2h, cooling to 25 ℃, continuing stirring for 24 h, stopping stirring, standing for ageing for 20 h, adding 10mL of 0.5mol/L aluminum source solution (AlCl ₃·6H₂ O is dissolved in water), stirring for 30min, and regulating the pH value of the system to 5 by using 2mol/L NaOH solution to obtain a reaction solution;

2) And (3) placing the reaction solution in a hydrothermal reaction kettle, performing hydrothermal crystallization reaction at 100 ℃ for 24 h, performing centrifugal washing for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min each time, then drying at 100 ℃ for 24: 24 h, grinding the obtained solid, finally roasting the solid, and heating to 550 ℃ from room temperature at a speed of 2 ℃/min, and calcining for 6h to obtain the aluminum-containing silicon-based adsorbent Al (0.1) -HECMS.

FIG. 3 is a graph showing the adsorption/desorption isotherms and pore size distribution of nitrogen containing silica-based adsorbent Al (0.1) -HECMS prepared in example 3. According to the data of physical adsorption and desorption of nitrogen, the specific surface area of the aluminum-containing silicon-based adsorbent prepared in the embodiment is 530.12m ²/g, the pore volume is 0.81cm ³/g, and the average pore diameter is 6.12nm.

FIG. 4 is a graph of equilibrium adsorption of Al (0.3) -HECMS, an aluminum-containing silicon-based adsorbent prepared in example 1, to glyphosate solutions of different pH values at 30deg.C. Taking a plurality of parts of glyphosate solution with the concentration of 100 mg/L, adjusting the pH value to 2, 3,4, 5, 6,7, 8, 9, 10 and 11 respectively for each part of 50mL, adding 0.05 g of Al (0.3) -HECMS adsorbent prepared in example 1 into each part of glyphosate solution, adsorbing for 24 hours at the temperature of 30 ℃, and testing the adsorption effect of the aluminum-containing silicon-based adsorbent on glyphosate (each sample is repeated three times and averaged). The result shows that when the pH value of the solution is 3.0, the adsorption amount of the adsorbent to the glyphosate is maximum, and can reach 83.16mg/g. At a pH of 3-11, the adsorption capacity rapidly decreases with increasing pH of the solution.

FIG. 5 is a graph of equilibrium adsorption of Al (0.3) -HECMS prepared in example 1 to glyphosate solutions of varying initial concentrations at 30 ℃. Taking a plurality of glyphosate solutions with different concentrations (the concentration is 25-300 mg/L), adjusting the pH value to 3 by 50mL, adding 0.05g of the adsorbent prepared in the example 1 into each glyphosate solution, adsorbing for 24 hours at the temperature of 30 ℃, and testing the adsorption effect of Al (0.3) -HECMS on the glyphosate solutions with different concentrations. It can be seen that as the initial concentration of glyphosate solution increases, the equilibrium adsorption of Al (0.3) -HECMS to glyphosate increases. When the initial concentration of glyphosate is greater than 250 mg/L, the equilibrium adsorption amount does not change much as the concentration increases, because the adsorption active site is gradually filled with glyphosate and adsorption reaches a saturated state when the initial concentration of glyphosate is greater than 250 mg/L. The adsorption amount was highest at C ₀ =300 mg/L, reaching 182.90 mg/g.

FIG. 6 is an XRD pattern of HECMS adsorbent prepared in comparative example 1 and of Al (0.3) -HECMS, which is an aluminum-containing silicon-based adsorbent prepared in example 1. Both samples showed a silica characteristic diffraction peak around 2θ=23°. The XRD pattern after Al doping is unchanged, which shows that Al ions are highly dispersed in the mesoporous silica.

Comparative example 1

An aluminum-free mesoporous silica adsorbent (HECMS) is prepared by the following steps:

1) Adding 3g of hydroxyethyl cellulose into 300mL of water, heating to 90 ℃ and stirring for dissolution to obtain a hydroxyethyl cellulose solution, dissolving 14.21g of Na ₂SiO₃·9H₂ O into 50 mL of water to obtain a sodium metasilicate solution, then dropwise adding the sodium metasilicate solution into the hydroxyethyl cellulose solution, keeping the temperature unchanged during the dropwise adding process, stirring for 30 min, then regulating the pH value of the system to 5-6 by using 2 mol/L of hydrochloric acid solution, stirring for 2h, cooling to 25 ℃, continuing stirring for 24 h, stopping stirring, and standing for 20 h to obtain a reaction solution;

2) And (3) centrifugally washing the reaction solution for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min, then drying at 100 ℃ for 12h, grinding the obtained solid, finally roasting the solid, and heating to 550 ℃ from room temperature at a speed of 2 ℃/min for 6h, thus obtaining the solid adsorbent HECMS.

FIG. 7 is a graph showing the adsorption/desorption isotherm and pore size distribution of HECMS of the comparative example 1. From the graph, the nitrogen adsorption and desorption curve of HECMS materials is an IV type isotherm, the nitrogen adsorption and desorption curve shows an H2 type hysteresis loop, and the Al (0.3) -HECMS has a mesoporous structure similar to HECMS. The adsorbent prepared in this comparative example was tested to have a specific surface area of 525.44 m ²/g, a pore volume of 0.47 cm ³/g and an average pore size of 3.59 nm.

2 Parts of glyphosate solution with the concentration of 100 mg/L is taken, each part of glyphosate solution is 50 mL, the pH value is adjusted to 3, HECMS prepared in the comparative example 1 is added into each part of glyphosate solution, the glyphosate solution is adsorbed for 24 hours at the temperature of 30 ℃, and the adsorption effect of HECMS on glyphosate is tested. The average value of the test results was taken, and the adsorption amount of HECMS to glyphosate was measured to be 2.65mg/g. Under the same conditions, the adsorption quantity of Al (0.3) -HECMS on glyphosate reaches 83.16mg/g. The aluminum doping modification HECMS of this example 1 is illustrated to greatly improve the adsorption performance of the adsorbent to glyphosate.

Comparative example 2

A preparation method of the zirconium-containing silicon-based adsorbent comprises the following steps:

1) Adding 3g of hydroxyethyl cellulose (with the viscosity of 250-450 mpa.s, 25 ℃) into 300mL of water, heating to 90 ℃ and stirring for dissolution to obtain a hydroxyethyl cellulose solution, dissolving 14.21g of Na ₂SiO₃·9H₂ O into 50 mL of water to obtain a sodium metasilicate solution, then dropwise adding the sodium metasilicate solution into the hydroxyethyl cellulose solution, keeping the temperature unchanged during the dropwise adding process, stirring for 30 min, regulating the pH value of the system to 5-6 by using 2mol/L of hydrochloric acid solution, stirring for 2h, cooling to 25 ℃, continuing stirring for 24h, stopping stirring, standing and aging for 20 h, adding 15 mL of 1.67 mol/L of zirconium salt solution (ZrOCl ₂·8H₂ O is obtained by dissolving in water), stirring for 30 min, and regulating the pH value of the system to 5 by using 2mol/L of NaOH solution to obtain a reaction solution A;

2) And (3) placing the reaction liquid A in a hydrothermal reaction kettle, performing hydrothermal crystallization reaction at 100 ℃ for 24 h, performing centrifugal washing for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min each time, then drying at 100 ℃ for 24: 24 h, grinding the obtained solid, finally roasting the solid, heating to 550 ℃ at the speed of 2 ℃/min from room temperature, preserving heat for 6h, and collecting the solid adsorbent Zr-HECMS.

FIG. 8 is a graph showing the adsorption/desorption isotherm and pore size distribution of nitrogen gas of Zr-HECMS prepared in comparative example 2. The adsorbent prepared in this comparative example 2 was tested to have a specific surface area of 258.62m ²/g, a pore volume of 0.71cm ³/g and an average pore diameter of 10.92nm. 2 parts of glyphosate solution with the concentration of 100 mg/L is taken, each part of glyphosate solution is 50 mL, the pH value is adjusted to be 3, 0.05 g part of Zr-HMS prepared in the comparative example 1 is added into each part of glyphosate solution, the adsorption is carried out for 24 hours at the temperature of 30 ℃, and the adsorption effect of the Zr-HMS on glyphosate is tested. The average value of the test results was taken, and the adsorption amount of glyphosate was measured to be 30.36mg/g.

Comparative example 3

A preparation method of the iron-containing silicon-based adsorbent comprises the following steps:

2) And (3) centrifugally washing the reaction solution for a plurality of times, wherein the centrifugal speed is 9000rpm, the centrifugal time is 10min, then drying at 100 ℃ for 12h, grinding the obtained solid, finally roasting the solid, and heating to 550 ℃ from room temperature at a speed of 2 ℃/min for 6h, thus obtaining the solid adsorbent HECMS. 0.84 g ferric chloride hexahydrate (FeCl ₃·6H₂ O) is weighed and dissolved in 50mL water, HECMS of 1.0 g is added into the solution, the solution is fully mixed and stirred for 24 hours, the water is evaporated at 80 ℃, and the solution is placed in a muffle furnace for roasting at 550 ℃ for 4 h (heating rate of 2 ℃/min), so that the mesoporous silica modified by the metallic iron is obtained and is named as Fe-HECMS.

The adsorbent prepared in this comparative example 3 was tested to have a specific surface area of 203.98m ²/g, a pore volume of 0.57cm ³/g and an average pore diameter of 10.68nm.

FIG. 9 is a graph of equilibrium adsorption of Fe-HECMS, a silicon-based adsorbent containing iron, prepared in comparative example 3, to glyphosate solutions of different pH values at 30deg.C. Taking a plurality of parts of glyphosate solution with the concentration of 100 mg/L, adjusting the pH value to 2, 3,4, 5, 6, 7, 8 and 9 respectively by 50 mL parts, adding 0.05 g of the Fe-HECMS adsorbent prepared in the example 1 into each part of glyphosate solution, adsorbing for 24 hours at the temperature of 30 ℃, and testing the adsorption effect of the silicon-containing adsorbent on the glyphosate (each sample is repeated three times and averaged). The result shows that when the pH value of the solution is 3.0, the adsorption quantity of the Fe-HECMS adsorbent to the glyphosate is maximum, and can reach 11.62mg/g.

Claims

1. The aluminum-containing silicon-based adsorbent is characterized in that amorphous mesoporous silica is taken as a framework of the adsorbent, metal element aluminum is doped after the amorphous mesoporous silica is synthesized, and the metal element aluminum is uniformly distributed on the surface of the framework and inside the framework, and the specific steps are as follows:

1) Preparing a hydroxyethyl cellulose solution and a sodium metasilicate solution with a certain concentration ratio, adding the sodium metasilicate solution into the stirred hydroxyethyl cellulose solution at 88-92 ℃, keeping the temperature, stirring, adjusting the pH of the system to 5-6 by using an acid solution, fully reacting for 16-24 hours at 25 ℃, stopping stirring, aging for 16-20 hours, adding an aluminum-containing solution under stirring, adjusting the pH of the solution to 4-6 by using a sodium hydroxide solution, and stirring for 0.5-2 hours to obtain a reaction solution, wherein the molar ratio of aluminum element in the aluminum salt solution to silicon element in the sodium metasilicate aqueous solution is 0.1-1:1;

2) And (2) placing the reaction liquid obtained in the step (1) into a hydrothermal reaction kettle, centrifuging, washing, drying, grinding and roasting the solid product after the hydrothermal crystallization reaction, wherein the hydrothermal crystallization reaction temperature is 85-95 ℃, and the hydrothermal crystallization reaction time is 16-40h.

2. The aluminum-containing silicon-based adsorbent according to claim 1, wherein the amorphous mesoporous silica has an average pore diameter of 6 to 20nm, a pore volume of 0.7 to 1.3cm ³/g, and a specific surface area of 350 to 500m ²/g.

3. A method for preparing the aluminum-containing silicon-based adsorbent according to claim 1 or 2, which comprises the following specific steps:

1) Preparing a hydroxyethyl cellulose solution and a sodium metasilicate solution with a certain concentration ratio, adding the sodium metasilicate solution into the stirred hydroxyethyl cellulose solution at 88-92 ℃, keeping the temperature, stirring, regulating the pH of the system to 5-6 by using an acid solution, fully reacting for 16-24 hours at 25 ℃, stopping stirring, aging for 16-20 hours, adding an aluminum-containing solution under stirring, regulating the pH of the solution to 4-6 by using a sodium hydroxide solution, and stirring for 0.5-2 hours to obtain a reaction solution;

2) And (3) placing the reaction liquid obtained in the step (1) into a hydrothermal reaction kettle, centrifuging, washing, drying, grinding and roasting a solid product after the hydrothermal crystallization reaction to obtain the solid adsorbent.

4. The method for producing an aluminum-containing silicon-based adsorbent according to claim 3, wherein the mass concentration ratio of the hydroxyethylcellulose solution and the sodium metasilicate solution in step 1) is 1:25-30, and the dropping speed of the sodium metasilicate solution is 2.5-5mL/min.

5. The method for producing an aluminum-containing silicon-based adsorbent according to claim 3, wherein the stirring temperature in step 1) is 88 to 92 ℃.

6. The method for preparing an aluminum-containing silicon-based adsorbent according to claim 3, wherein in the step 1), the aluminum source is one of AlCl ₃·8H₂O、Al₂(SO₄)₃、Al₂Na₂O₄, the concentration of the aluminum-containing solution is 0.01-0.2 mol/L, and the molar ratio of aluminum element in the aluminum salt solution to silicon element in the sodium metasilicate aqueous solution is 0.1-1:1; stirring time is 30-60min after adding the aluminum source solution.

7. The method of preparing an aluminum-containing silicon-based adsorbent according to claim 3, wherein the acid solution in step 1) is a 6.4 to 7.5% hydrochloric acid solution; the concentration of the sodium hydroxide solution is 1-2mol/L.

8. The method of preparing aluminum-containing silicon-based adsorbent according to claim 3, wherein the hydrothermal crystallization reaction temperature in step 2) is 85-95 ℃ and the hydrothermal crystallization reaction time is 16-40h.

9. The method of preparing aluminum-containing silicon-based adsorbent according to claim 3, wherein the roasting process conditions in step 2) are: heating to 450-550 ℃ at room temperature at a heating rate of 2-5 ℃/min, and preserving heat for 6-10h.

10. Use of the aluminum-containing silicon-based adsorbent of claim 1 or 2 for removing glyphosate from water.