阅读说明：本技术 一种低成本制备纳米钛硅分子筛的方法 (Method for preparing nano titanium silicalite molecular sieve at low cost ) 是由 宋万仓 臧甲忠 于海斌 洪鲁伟 刘冠锋 李晨 郭春磊 石芳 季超 费亚南 于 2020-12-31 设计创作，主要内容包括：本发明提供一种低成本制备纳米钛硅分子筛的方法,其特征在于将硅源、钛源和晶种混合均匀,加入无机酸将混合溶液pH值调节至1～6范围内,在一定温度下老化一定的时间,然后过滤、洗涤、干燥得到分子筛晶化前驱体；将钛硅混合前驱体与含有模板剂的碱性水溶液混合,置于密闭容器中,120～210℃晶化0.5～3d,过滤分离、干燥和焙烧,得到钛硅分子筛。本发明提供的钛硅分子筛合成方法对原料纯度要求低,同时分子筛模板剂水溶液可重复利用,降低钛硅分子筛合成成本同时减少废水排放。(The invention provides a method for preparing a nano titanium-silicon molecular sieve at low cost, which is characterized by uniformly mixing a silicon source, a titanium source and a seed crystal, adding inorganic acid to adjust the pH value of a mixed solution to be within a range of 1-6, aging for a certain time at a certain temperature, and then filtering, washing and drying to obtain a molecular sieve crystallization precursor; mixing the titanium-silicon mixed precursor with an alkaline aqueous solution containing a template agent, placing the mixture in a closed container, crystallizing the mixture for 0.5-3 d at the temperature of 120-210 ℃, filtering, separating, drying and roasting to obtain the titanium-silicon molecular sieve. The synthesis method of the titanium silicalite molecular sieve provided by the invention has low requirement on the purity of the raw material, and the molecular sieve template aqueous solution can be recycled, thereby reducing the synthesis cost of the titanium silicalite molecular sieve and reducing the discharge of wastewater.)

1. A method for preparing a nano titanium silicalite molecular sieve with low cost is characterized in that: the method comprises the following steps:

(1) dispersing S-1 or TS-1 into an aqueous solution containing inorganic base, and stirring for 0.5-6 h at 20-100 ℃ to obtain a material A; wherein the solution contains 10-50 wt% of molecular sieve and 0.05-3.0 mol/L of inorganic base; wherein the inorganic base is at least one of NaOH and KOH;

(2) mixing the material A and a silicon source, stirring for 0.5-6 h, adding 1-10 mol/L dilute acid to adjust the pH to 1-6, and continuously stirring for 0.5-6 h to obtain a glue solution B; slowly adding a titanium source dispersed in alcohol into the glue solution B under vigorous stirring, stirring for 0.5-3 h, then adding an aqueous solution containing a gel auxiliary agent, heating to 20-100 ℃, aging for 1-24 h, filtering, washing for 3-10 times by deionized water to obtain a product with the composition of SiO₂:TiO₂:Na₂O：H₂Colloid C with the molar ratio of O being 1: 0.01-0.1: 0-0.003: 0.5-10;

(3) mixing the colloid C with an alkaline aqueous solution containing a template agent according to a solid-to-liquid ratio of 1g: 1-10 mL, placing the mixture in a closed synthesis kettle, crystallizing the mixture for 0.5-7 days at 120-210 ℃, and filtering, washing, drying and roasting the crystallized mixture to obtain a nano titanium silicalite molecular sieve; the separated template agent-containing aqueous solution is recycled;

wherein the titanium source is one or more of tetrabutyl titanate, tetraisopropyl titanate, titanium sulfate, titanium tetrachloride or titanium trichloride;

the silicon source is at least one of water glass, silica gel and silica sol.

2. The method of claim 1, wherein the alcohol is at least one of ethylene glycol, propylene glycol, isopropanol or glycerol.

3. The method of claim 1, wherein the dilute acid is at least one of hydrochloric acid, nitric acid, sulfuric acid, and acetic acid.

4. The method of claim 1, wherein the template is at least one of tetrapropylammonium bromide, tetrapropylammonium chloride or tetrapropylammonium hydroxide; the alkaline aqueous solution is at least one aqueous solution of NaOH, KOH, ammonia water, ethylamine, triethanolamine and n-butylamine; wherein the composition of the alkaline aqueous solution containing the template agent is that the concentration of the template agent is 0.03-0.15 mol/L, and the concentration of alkali is 0-0.2 mol/L and is not 0.

5. The method of claim 1, wherein the gelling agent is at least one of urea, ammonium bicarbonate, ammonium carbonate, ammonium phosphate, ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium fluoride, or ammonium fluoroborate.

6. The method for preparing the nano titanium silicalite molecular sieve according to claim 1, wherein the concentration of the aqueous solution of the gel assistant is 5-50 wt%, and the gel assistant and SiO are₂The molar ratio of (A) to (B) is 0.03 to 0.25.

7. The method of claim 1, wherein the template-containing aqueous alkaline solution separated after crystallization is recycled one or more times.

Technical Field

The invention belongs to the field of preparation of catalytic materials, and relates to a synthesis method of a titanium silicalite molecular sieve, in particular to a method for preparing a nano titanium silicalite molecular sieve at low cost.

Background

The titanium-silicon molecular sieve (TS-1) is a novel heteroatom molecular sieve developed in the early 80 s of the 20 th century, and the transition metal element titanium is introduced into an MFI type molecular sieve structure to endow the MFI type molecular sieve with excellent catalytic selective oxidation performance. The TS-1 molecular sieve can adopt pollution-free hydrogen peroxide as an oxidant, catalyzes a plurality of organic matters to be selectively oxidized (such as olefin epoxidation, alkane partial oxidation, alcohol oxidation, phenol hydroxylation, ketone ammoxidation and the like), and has the advantages of energy conservation, environmental protection and the like which cannot be achieved by a traditional oxidation system.

In 1983, Taramasso reported a method for synthesizing a titanium silicalite molecular sieve in a patent US4410501 for the first time by a hydrothermal crystallization method. The method is a classical method for synthesizing the titanium-silicon molecular sieve, and the synthesis process is as follows: no CO under the protection of nitrogen₂Slowly dripping a template agent tetrapropylammonium hydroxide (TPAOH (25 wt.%, without inorganic alkali)) aqueous solution into Tetraethoxysilane (TEOS) under the atmosphere, then slowly adding tetraethyl titanate (TEOT), stirring for 1h, then heating, removing alcohol and supplementing water to obtain a synthetic glue solution, crystallizing for 10d under the autogenous pressure of 175 ℃, separating, washing, drying and roasting to obtain the titanium-silicon molecular sieve product. Thangaraj et al propose a TS-1 improved synthesis method (Zeolite, 1992, Vol.12, p934-950) on the basis of the classical synthesis method, the method selects tetrabutyl titanate (TBOT) with weak hydrolytic activity as a titanium source, disperses the titanium source into isopropanol, and then mixes the titanium source with a hydrolyzed silicon source to match the hydrolysis rate of the titanium source and the silicon source, thereby increasing the framework titanium content in the molecular sieve. The classical method andthe hydrolysis and nucleation conditions of the titanium-silicon molecular sieve synthesized by the classical improved method are not easy to control, so that the synthesized molecular sieve has low catalytic activity and poor repeatability; the patented method has high requirements on the purity of raw materials, particularly organic template agent TPAOH, and large dosage, so that the cost of the molecular sieve is high, and the reduction of the cost of the titanium-silicon molecular sieve is always a hotspot in the field.

EP appl.0543247 discloses a titanium-silicon molecular sieve with the grain size of 10 μm prepared by hydrothermal synthesis by using tetrapropylammonium bromide as a template agent, ammonia water as an alkali source, colloidal silicon dioxide as a silicon source and tetrabutyl titanate as a titanium source after complexing with hydrogen peroxide.

Patent CN1060411C discloses a method for synthesizing a titanium-silicon molecular sieve, which uses silica gel and tetrabutyl titanate as a silicon source and a titanium source, and a mixture of tetraethyl ammonium hydroxide and tetrabutyl ammonium hydroxide as a template agent to synthesize the titanium-silicon molecular sieve.

Patent CN100344375C discloses a method for synthesizing a titanium silicalite molecular sieve by using silica sol as a silicon source, organic titanate as a titanium source, and hexamethyleneimine and piperidine as templating agents.

Patent CN01145256.0 proposes a method for synthesizing small-grained titanium silicalite molecular sieves in an inexpensive system, using titanium tetrachloride (TiCl)₄) Is a titanium source, silica sol is used as a silicon source, and is in TPABr-NH₄In an OH system, a nano-scale titanium silicalite molecular sieve is taken as a seed crystal to synthesize the titanium silicalite molecular sieve by hydrothermal synthesis, and the addition of the seed crystal can obviously accelerate the crystallization rate of TS-1 and shorten the crystallization time. The grain size obtained by this method is about 0.85. mu. m.times.0.4. mu. m.times.0.15. mu.m.

Patent CN101913620A proposes a method for preparing a small-grain titanium silicalite molecular sieve by changing the mode of adding seed crystals in a cheap synthesis system. The method takes silica sol as a silicon source, titanium tetrachloride or tetrabutyl titanate as a titanium source, tetrapropylammonium bromide (TPABr) as a template agent, organic amine as an alkali source, nano TS-1 mother liquor directly used as seed crystals without separation, and the titanium silicalite molecular sieve is obtained by hydrothermal synthesis. The molecular sieve has a particle size of less than 1 μm.

Patent CN104418342A provides a method for synthesizing a titanium silicalite molecular sieve by using piperidine quaternary ammonium hydroxide as a template.

Patent CN101767036A discloses a preparation method of a titanium silicalite TS-1 catalyst. Cheap inorganic silicon-titanium raw material is adopted, a small amount of tetrapropyl ammonium hydroxide or tetrapropyl ammonium bromide is used as template agent, and inorganic alkali such as ammonia water is used as alkali source to synthesize the titanium-silicon molecular sieve. The method adopts cheap raw materials, so that the production cost is greatly reduced.

Patent CN103818921A proposes a method for preparing a TS-1 molecular sieve by using a composite template, which is characterized in that one or more auxiliary templates are introduced, the dosage of the TAPOH template is reduced, and the size of the molecular sieve is regulated and controlled. The auxiliary template agent is one of fiber material or organic alkali compound or the mixture of the fiber material and the organic alkali compound.

Patent CN102627293A discloses a method for preparing titanium silicalite TS-1 by two or more hydrolysis processes, which significantly reduces the amount of organic base used in the synthesis, thereby reducing the production cost.

Patent CN1939651A discloses a new method for synthesizing TS-1 by a dry glue method, which adopts inorganic silicon as a silicon source, omits the alcohol removal process, reduces the dosage of a template agent and reduces the synthesis cost.

Patent CN99107790.3 discloses a new method for synthesizing TS-1 by a microwave method, which has the advantages of less environmental pollution, small grain size of the prepared molecular sieve, high yield and the like.

The patent uses cheap compounds to replace expensive tetrapropylammonium hydroxide as a template agent, and the amount of tetrapropylammonium hydroxide (TPAOH) is reduced by optimizing a synthesis process to prepare the cheap titanium-silicon molecular sieve, but the titanium-silicon molecular sieve prepared by the patent has the problems of larger crystal grains, low catalytic oxidation activity and the like, and a large amount of waste water containing COD is generated in the synthesis process of the titanium-silicon molecular sieve.

Disclosure of Invention

The invention aims to provide a method for preparing a nano titanium silicalite molecular sieve at low cost, which adopts cheap raw materials, reduces the dosage of a template agent, optimizes a synthesis process, reduces the discharge of high COD wastewater and prepares the nano titanium silicalite molecular sieve at low cost under the condition of reducing environmental influence.

The method for preparing the nano titanium silicalite molecular sieve at low cost adopts cheap silicon sources and titanium sources to reduce the synthesis cost; preparing proper silicon-titanium mixed gel by hydrolysis-gel under acidic condition, and reducing the dosage of the template agent by adopting aqueous solution with lower template agent concentration for hydrothermal crystallization; the aqueous solution containing the template agent separated after crystallization is recycled, so that the cost is reduced, and the pollution problem caused by wastewater discharge is avoided.

More specifically, the invention is realized by the following technical scheme: a method for preparing a nano titanium silicalite molecular sieve at low cost comprises the following steps:

(1) dispersing S-1 or TS-1 into an aqueous solution containing inorganic base, and stirring for 0.5-6 h at 20-100 ℃ to obtain a material A; wherein the content of the molecular sieve in the solution is 10-50 wt%, the concentration of the inorganic alkaline aqueous solution is 0.05-3.0 mol/L, and the preferred concentration of the inorganic alkaline aqueous solution is 0.2-3 mol/L; wherein the inorganic base is at least one of NaOH and KOH;

(2) mixing the material A and a silicon source, stirring for 0.5-6 h, adding 1-10 mol/L dilute acid to adjust the pH to 1-6, and continuously stirring for 0.5-6 h to obtain a glue solution B; slowly adding a titanium source dispersed in alcohol into the glue solution B under vigorous stirring, stirring for 0.5-6 h, then adding an aqueous solution containing a gel auxiliary agent, heating to 20-100 ℃, aging for 1-24 h, filtering, washing for 3-10 times by deionized water to obtain a product with the composition of SiO₂:TiO₂:Na₂O：H₂Colloid C having O in a molar ratio of 1:0.01 to 0.1:0 to 0.003:0.5 to 10;

(3) mixing the colloid C with an alkaline aqueous solution containing a template agent according to a solid-to-liquid ratio of 1g: 1-10 ml, placing the mixture in a closed synthesis kettle, crystallizing the mixture for 0.5-3 d at 120-210 ℃, and filtering, washing, drying and roasting the crystallized mixture to obtain a nano titanium silicalite molecular sieve; the separated template agent-containing aqueous solution is recycled;

wherein the titanium source is tetrabutyl titanate, tetraisopropyl titanate, titanium sulfate (Ti (SiO)₄)₂) Titanium tetrachloride (TiCl)₄) Or titanium trichloride (TiCl)₃) One or more of the above;

the silicon source is at least one of water glass, silica gel and silica sol.

In the above embodiment, the polyol is preferably at least one of isopropyl alcohol, ethylene glycol, propylene glycol, and glycerin.

The diluted acid is at least one of hydrochloric acid, nitric acid, sulfuric acid and acetic acid water solution, and the preferable concentration is 2-6 mol/L.

The template agent is at least one of tetrapropylammonium bromide, tetrapropylammonium chloride or tetrapropylammonium hydroxide; the alkaline aqueous solution is at least one aqueous solution of NaOH, KOH, ammonia water, ethylamine, triethanolamine and n-butylamine; wherein the composition of the alkaline aqueous solution containing the template agent is that the concentration of the template agent is 0.03-0.15 mol/L, preferably 0.05-0.15 mol/L; the alkali concentration is 0 to 0.2mol/L and is not 0.

The gel auxiliary agent is at least one of urea, ammonium bicarbonate, ammonium carbonate, ammonium phosphate, ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium fluoride or ammonium fluoroborate, the concentration of the aqueous solution of the gel auxiliary agent is 5-50 wt%, and the gel auxiliary agent and SiO are mixed₂The molar ratio of (A) to (B) is 0.03 to 0.25.

The composition of the mixed solution of the titanium source and the polyhydric alcohol is 1: 5-20 (molar ratio).

And the alkaline aqueous solution containing the template agent separated after crystallization is recycled for one time or multiple times.

The method adopts cheap raw materials, obtains gel through hydrolysis under acidic conditions, and washes the gel to obtain a molecular sieve crystallization precursor suitable for crystallization, thereby reducing the raw material cost for synthesizing the titanium silicalite molecular sieve; the crystallization process is different from the polymerization-crystallization conversion process of silicon-titanium species in the conventional hydrothermal crystallization process, the titanium-silicon species is directly crystallized and converted, the dosage of the template agent is small, the purity requirement of the template agent is reduced, the separated liquid after crystallization is recycled, the cost is reduced, and the generation of waste water is reduced.

Compared with the prior art, the technology of the invention has the following remarkable advantages: 1) the invention prepares the molecular sieve crystallization precursor with uniformly dispersed titanium species under the acidic condition, can effectively avoid the generation of non-framework titanium species in the molecular sieve, and improves the catalytic performance of the synthesized titanium-silicon molecular sieve. 2) The method for preparing the titanium-silicon molecular sieve crystallization precursor does not need alcohol removal operation in the preparation process of the titanium-silicon molecular sieve crystallization precursor, is simple to operate, and is beneficial to industrial production. 3) The titanium-silicon molecular sieve prepared by the method selects cheap silica sol or water glass as a silicon source, the amount of the template agent TPAOH with high cost is less, and the preparation cost of the titanium-silicon molecular sieve is effectively reduced. 4) The invention adopts the technology that the alkaline aqueous solution containing the template agent can be repeatedly utilized in the process of preparing the titanium-silicon molecular sieve, has less high COD wastewater output which seriously affects the environment and meets the requirements of environmental protection.

Drawings

FIG. 1 is an X-ray diffraction (XRD) pattern of a molecular sieve sample prepared in comparative example and example;

FIG. 2 is a graph of the ultraviolet-visible absorption (UV-Vis) spectra of samples of molecular sieves prepared in comparative examples and examples;

FIG. 3 is a scanning electron micrograph of a sample of the molecular sieve prepared in the example.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

Comparative example 1

The titanium silicalite TS-1 is prepared according to a synthesis method of a document (Zeolite, 1992, Vol.12, P943-950). Adding 50g of ethyl orthosilicate into a three-neck flask, adding 58.6g of TPAOH aqueous solution (20 wt.%) and 64g of deionized water at 25 ℃ under stirring, hydrolyzing for 1.5h to obtain a hydrolyzed solution of the ethyl orthosilicate, slowly adding a solution consisting of 2g of tetrabutyl titanate and 15g of anhydrous isopropanol under vigorous stirring, heating to 85 ℃, and continuously reacting to remove alcohol for 6h to obtain clear silicon-titanium colloid. And (3) putting the obtained colloid into a stainless steel sealed synthesis kettle with a polytetrafluoroethylene lining, crystallizing for 3d at the autogenous pressure of 170 ℃, washing and drying a crystallized product, and roasting for 5h at 540 ℃ to obtain a TS-1 sample, which is marked as a comparative sample 1.

The X-ray diffraction (XRD) and ultraviolet-visible absorption (UV-Vis) spectra of the sample are shown in fig. 1 and fig. 2, respectively.

Comparative example 2

According to the method described in example 1 of patent CN101913620A, 1.4mL of titanium tetrachloride was dropped into 12mL of isopropanol, and the mixture was stirred until HCl was completely volatilized, to obtain an isopropanol solution of titanium tetrachloride. Adding 81mL of deionized water into 100mL of 30% silica sol, stirring for 10min, mixing with an alcoholic solution of titanium tetrachloride, stirring for 30min, sequentially adding 24g of tetrapropylammonium bromide, 50mL of 65 wt% ethylamine aqueous solution, 12mL of nano-scale titanium silicalite molecular sieve mother solution and 78mL of deionized water, stirring for 30min, adding a glue solution into a stainless steel crystallization kettle with a polytetrafluoroethylene lining, crystallizing at 170 ℃ for 2d, washing and drying a crystallized product, and roasting at 540 ℃ for 6h to obtain the titanium silicalite TS-1, which is recorded as a comparative sample 2.

The X-ray diffraction (XRD) and ultraviolet-visible absorption (UV-Vis) spectra of the sample are shown in fig. 1 and fig. 2, respectively.

Example 1

Dispersing a 1.5g S-1 molecular sieve into 9mL of 0.5mol/L NaOH aqueous solution, and stirring at room temperature for 12h to obtain a material A;

the above material A was added to 153.8g of water glass (SiO)₂Content 20 wt%, mole number 3.2), adding 76.4g deionized water, stirring at room temperature for 3h, slowly adding 43.3mL dilute sulfuric acid aqueous solution (6mol/L), adjusting pH value of the solution to 2.2, and continuing stirring for 30min to obtain glue solution B; slowly adding a mixed solution of 4.3g of tetrabutyl titanate and 31.4g of isopropanol under stirring, stirring for 30min, adding 52.6g of ammonium carbonate aqueous solution (15 wt%), heating to 60 ℃, aging for 12h, filtering, and washing for 3 times to obtain a required molecular sieve crystallization precursor C;

dispersing the prepared crystallization precursor into 153.8mL of TPAOH aqueous solution (0.1mol/L), crystallizing for 1.5d at 170 ℃ in a crystallization kettle, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as sample 1. And (4) recycling the filtered template-containing aqueous solution after crystallization.

The X-ray diffraction (XRD) and ultraviolet visible absorption (UV-Vis) spectra of the sample are shown in FIG. 1 and FIG. 2, respectively, and the electron micrograph of the sample is shown in FIG. 3.

Example 2

Dispersing 1.5g of TS-1 molecular sieve into 9mL of 0.5mol/L NaOH aqueous solution, and stirring at room temperature for 12h to obtain a material A;

the above material A was added to 102.5g of silica Sol (SiO)₂30 wt.%), 127.7g of deionized water were addedStirring for 3h with water at room temperature, slowly adding 34.2mL of dilute hydrochloric acid aqueous solution (3mol/L), adjusting the pH value of the solution to 3.5, and continuously stirring for 30min to obtain a glue solution B; slowly adding a mixed solution of 2.4g of titanium tetrachloride and 39.8g of propylene glycol while stirring, stirring for 30min, adding 30.8g of urea aqueous solution (20 wt%), heating to 80 ℃, aging for 9h, filtering, and washing for 2 times to obtain a required f molecular sieve crystallization precursor C;

dispersing the prepared molecular sieve crystallization precursor C into 92.5mL of mixed aqueous solution of TPABr (0.05mol/L) and ethylamine (0.1mol/L), crystallizing at 170 ℃ in a crystallization kettle for 2d, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the titanium-silicon molecular sieve sample as a sample 2. And (4) recycling the filtered template-containing aqueous solution after crystallization.

The X-ray diffraction (XRD) and ultraviolet visible absorption (UV-Vis) spectra of the sample are shown in FIG. 1 and FIG. 2, respectively, and the electron micrograph of the sample is shown in FIG. 3.

Example 3

Dispersing a 1.5g S-1 molecular sieve into 11mL of 0.3mol/L KOH aqueous solution, and stirring at room temperature for 12h to obtain a material A;

the above material A was added to 153.8g of water glass (SiO)₂Content 20 wt%, mole number 3.2), adding 96.4g deionized water, stirring at room temperature for 3h, slowly adding 23.1mL dilute sulfuric acid aqueous solution (9mol/L), adjusting pH value of the solution to 1.8, and continuing stirring for 30min to obtain glue solution B; slowly adding a mixed solution of 4.9g of titanium tetrachloride and 29.4g of isopropanol under stirring, stirring for 30min, adding 15.8g of ammonium fluoride aqueous solution (30 wt%), heating to 75 ℃, aging for 6h, filtering, and washing for 5 times to obtain a required crystallization precursor C;

dispersing the prepared crystallization precursor C into 123.0mL of TPABr (0.05mol/L) and n-butylamine (0.06mol/L) aqueous solution, crystallizing at 170 ℃ for 3d in a crystallization kettle, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as 3. And (4) recycling the filtered template-containing alkaline aqueous solution after crystallization.

The X-ray diffraction (XRD) and ultraviolet-visible absorption (UV-Vis) spectra of the sample are shown in fig. 1 and fig. 2, respectively.

Example 4

Dispersing 1.8g of TS-1 molecular sieve into 11mL of 0.6mol/L NaOH aqueous solution, and stirring at room temperature for 9 hours to obtain a material A;

the above material A was added to 153.8g of water glass (SiO)₂Content 20 wt%, mole number 3.2), adding 96.4g deionized water, stirring at room temperature for 3h, slowly adding 69.3mL dilute sulfuric acid aqueous solution (2.5mol/L) to adjust pH to 3.2, and continuing stirring for 30min to obtain glue solution B; slowly adding 4.1g of titanium sulfate while stirring, stirring for 30min, adding 44.3g of ammonium carbonate aqueous solution (20 wt%), heating to 50 ℃, aging for 6h, filtering and washing for 5 times to obtain a required crystallization precursor C;

dispersing the prepared crystallization precursor C into 123.0mL of TPABr (0.05mol/L) and triethanolamine (0.08mol/L) aqueous solution, crystallizing at 170 ℃ for 2d in a crystallization kettle, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as 4. And (4) recycling the filtered template-containing alkaline aqueous solution after crystallization.

The X-ray diffraction (XRD) and ultraviolet-visible absorption (UV-Vis) spectra of the sample are shown in fig. 1 and fig. 2, respectively.

Example 5

Molecular sieve crystallization precursor C preparation example 1 was repeated;

dispersing the prepared crystallization precursor C into 92.8mL of solution consisting of the filtrate obtained after crystallization and recovered in example 1 and 60mL of TPAOH (0.15mol/L), placing the solution in a crystallization kettle for crystallization at 175 ℃ for 2d, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as 5;

the X-ray diffraction (XRD) and ultraviolet visible absorption (UV-Vis) spectra of the sample are shown in FIG. 1 and FIG. 2, respectively, and the electron micrograph of the sample is shown in FIG. 3.

Example 6

Molecular sieve crystallization precursor C preparation example 1 was repeated;

dispersing the prepared crystallization precursor C into 92.8mL of solution consisting of the filtrate obtained after crystallization and recovered in example 1 and 90mL of TPAOH (0.10mol/L), placing the solution in a crystallization kettle for crystallization at 175 ℃ for 2d, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as 6;

the X-ray diffraction (XRD) and ultraviolet-visible absorption (UV-Vis) spectra of the sample are shown in fig. 1 and fig. 2, respectively.

Example 7

Preparation of molecular sieve crystallization precursor C example 2 was repeated;

dispersing the prepared crystallization precursor C into 60mL of solution prepared by recovering the crystallized filtrate in the embodiment 2 and 32.5mL of mixed aqueous solution of TPABr (0.05mol/L) and ethylamine (0.1mol/L), placing the solution in a crystallization kettle for crystallization at 170 ℃ for 2d, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the sample as 7;

the X-ray diffraction (XRD) and ultraviolet visible absorption (UV-Vis) spectra of the sample are shown in FIG. 1 and FIG. 2, respectively, and the electron micrograph of the sample is shown in FIG. 3.

Example 8

Preparation of molecular sieve crystallization precursor C example 2 was repeated;

and dispersing the prepared crystallization precursor C into 92.5mL of the crystallized filtrate recovered in the embodiment 2, crystallizing the filtrate in a crystallization kettle at 170 ℃ for 3d, filtering, drying and roasting to obtain a titanium-silicon molecular sieve sample, and recording the titanium-silicon molecular sieve sample as a sample 8.