Preparation method and device of nanoscale titanium oxide particle sol

Abstract

The invention provides a preparation method and device of nanoscale titanium oxide particle sol, the device adopts a whole membrane process to control the preparation process of the titanium oxide particle sol, and the specific content is as follows: dynamic microporous ceramic membrane feeding, dynamic rotation and microporous permeation, and high homogenization of a reaction system is realized; separating, concentrating and washing the intermediate product by the dynamic ceramic membrane, and purifying the intermediate product; the dynamic microporous ceramic reactor is used for carrying out online particle grading on a reaction product to realize homogenization of product particles; and the pervaporation membrane efficiently separates the alcohol and the water, so that the alcohol is recycled. According to the method, reactants are added by adopting a membrane reactor D1 (a dynamic rotating membrane reactor), so that the reactants are dispersed more uniformly in a system, and over-wide particle size distribution of a product caused by over-high or over-low local concentration is inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-sols, and in particular to a method and a device for preparing nano-scale titanium oxide particle sol. Background Art

[0002] The sol-gel process is one of the core technologies for preparing inorganic ceramic separation membranes, such as microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF). The process typically involves four key steps: synthesis of a gel precursor, uniform deposition of the sol on a support surface, drying of the gel network, and finally high-temperature sintering. The particle size distribution of the gel is a key factor in determining the final membrane performance, directly impacting its pore size distribution and separation efficiency. In theory, a narrower gel particle size distribution promotes the formation of a membrane structure with uniform pore size and high separation precision.

[0003] In the existing technology, the preparation of titanium dioxide sol generally adopts the hydrolysis reaction method. This method attempts to optimize the gel particle size distribution by regulating parameters such as the type of precursor (such as titanate), precursor concentration, hydrolysis ratio (water / precursor molar ratio), reaction temperature and time, type and amount of peptizer (such as nitric acid, acetic acid). However, this process has the following inherent defects: (1) Uneven dispersion of reactants: During the mixing and hydrolysis process, the precursor concentration may be too high or too low in local areas. Too high a concentration will cause the gel particles to grow abnormally and form large-sized agglomerates; too low a concentration will easily generate ultrafine particles. This bimodal distribution of particle size will be transferred to the sintered membrane layer, resulting in an excessively wide membrane pore size distribution and reduced separation selectivity. (2) High sensitivity of process control: The existing method is extremely sensitive to subtle changes in reaction conditions (such as temperature gradient, stirring efficiency), making it difficult to ensure batch-to-batch consistency in large-scale production.

[0004] Therefore, the uncontrollable "reactant dispersion effect" in existing sol-gel processes has become a bottleneck restricting the production of high-performance ceramic membranes. There is an urgent need to develop an improved process that can significantly improve the uniformity of sol dispersion and achieve gel synthesis with a narrow particle size distribution to meet the application requirements of high-precision separation membranes.

[0005] In view of this, it is necessary to improve the titanium oxide sol preparation method in the prior art to solve the above problems.

[0006] The first object of the present invention is to disclose a device for preparing nano-scale titanium oxide particle sol, which adopts a full-membrane process to control the preparation process of titanium oxide particle sol. The specific contents include: ① dynamic microporous ceramic membrane feeding, dynamic rotation + microporous infiltration, to achieve high homogenization of the reaction system; ② dynamic ceramic membrane separation, concentration and washing of intermediate products, and purification of intermediate products; ③ dynamic microporous ceramic reactor online particle classification of reaction products to achieve homogenization of product particles; ④ pervaporation membrane efficient separation of alcohol and water, to achieve alcohol reuse.

[0007] To achieve the above-mentioned objectives, the present invention provides a device for preparing nano-scale titanium oxide particle sol, comprising a membrane reactor D1, a membrane separator D2, a membrane separator D3, a membrane reactor D4 and a membrane separator D5 connected in sequence; the concentrated liquid side of the membrane reactor D1 is connected to the concentrated liquid side of the membrane separator D2, and the clear liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane separator D3; the concentrated liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane reactor D4, the clear liquid side of the membrane reactor D4 is connected to the concentrated liquid side of the membrane separator D5, and the clear liquid side of the membrane separator D5 is connected to the concentrated liquid side of the membrane reactor D4.

[0008] In some embodiments, the concentrate side of the membrane separator D2 is connected to a pure water source.

[0009] In some embodiments, the clear liquid side of the membrane separator D2 is connected to a reverse osmosis system.

[0010] In some embodiments, the membrane reactor D1 is a dynamic rotating membrane reactor, the filter element of the membrane reactor D1 is a disc membrane, and the filtration accuracy of the membrane is 2-2000 nm.

[0011] In some embodiments, the membrane reactor D1 includes a shell (1), a hollow rotating shaft (2) passing through the bottom of the shell, a driver (3) connected to the bottom of the hollow rotating shaft (2), the upper part of the hollow rotating shaft (2) is located inside the shell (1) and is installed with a plurality of filter elements (5) and spacers (6), the upper part of the shell (1) is also provided with a first liquid inlet (10) and a liquid outlet (11), and the lower part of the hollow rotating shaft (2) is provided with a second liquid inlet (4).

[0012] In some embodiments, the membrane reactor D1 further comprises a stirring device (9) located above the hollow rotating shaft (2).

[0013] In some embodiments, the filter element (5) and the spacer (6) are arranged in sequence and spaced apart, and the filter element (5) is used as a distributor.

[0014] In some embodiments, the membrane separator D3 is a molecular sieve membrane separator, and the filtering element of the membrane separator D3 is any one of a disc membrane, a tube membrane or a hollow fiber membrane.

[0015] In some embodiments, the filtering element of the membrane separator D3 is made of one or more of A type, CHA type or MFI type.

[0016] The second object of the present application is to disclose a method for preparing a nano-sized titanium oxide particle sol, which adopts a whole membrane process of membrane dispersion, membrane separation, membrane concentration, membrane washing, membrane fractionation and membrane recovery, realizes continuous preparation of the nano-sized titanium oxide particle sol, and makes the particle size distribution of the target product more uniform, and the recovery rate of the alcohol solvent A reach above 95%.

[0017] To achieve the above object, the present application provides a method for preparing a nano-sized titanium oxide particle sol, comprising the following steps:

[0018] S1: uniformly mixing an alcohol solvent A and a titanium precursor B, controlling the concentration of the titanium precursor B, and obtaining a reactant AB;

[0019] S2: uniformly mixing the alcohol solvent A and deionized water, controlling the concentration of the deionized water, and obtaining a reactant AH;

[0020] S3: adding the reactant AB and the reactant AH into a membrane reactor D1 respectively for reaction, and controlling the feeding concentration of the reactant AH, and obtaining an intermediate product C;

[0021] S4: passing the intermediate product C into a membrane separator D2, separating and concentrating the solid-phase intermediate product C and the liquid-phase material, and then passing the liquid-phase material into a membrane separator D3 for post-treatment to obtain recycled alcohol solvent A;

[0022] S5: adding deionized water into the membrane separator D2 multiple times to wash the solid-phase intermediate product C multiple times, and then passing the intermediate product C into a membrane reactor D4 after washing;

[0023] S6: adding a peptizing agent D into the membrane reactor D4 for reaction, and controlling the concentration of the peptizing agent D, and obtaining a low-concentration target product E;

[0024] S7: concentrating the target product by a membrane separator D5 to obtain a high-concentration nano-sized titanium oxide particle sol.

[0025] In some embodiments, the alcohol solvent A is one or more of ethanol, n-propanol, isopropanol and n-butanol, and the titanium precursor B is one or more of tetraethyl titanate, n-propyl titanate, tetraisopropyl titanate and n-butyl titanate.

[0026] In some embodiments, the concentration of the titanium precursor B is C(Ti)=0.001-0.5 mol / L, and the concentration of the deionized water is C(H2O)=0.001-55.5 mol / L.

[0027] In some embodiments, the peptizing agent D is one or more of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, acetic acid, and perchloric acid.

[0028] In some embodiments, the reactant AH enters the membrane reactor D1 through a second inlet, the reactant AB enters the membrane reactor D1 through a first inlet, and the reactant AH is uniformly dispersed in the membrane reactor D1 through the membrane layer micropores of the filter element (5) to avoid local over-concentration, and the reactant AH and the reactant AB contact and hydrolyze on the outer surface of the filter element (5).

[0029] In some embodiments, the molar ratio of the reactant AH to the reactant AB in S1 is n(Ti):n(H2O)=0.01-1, the reaction temperature of the membrane reactor D1 is 5-80°C, the reaction time is 5-120 min, the transmembrane pressure difference of the membrane reactor D1 is 0-300 kPa, and the rotation speed of the filter element of the membrane reactor D1 is 0-1000 r / min.

[0030] In some embodiments, the molar ratio of the peptizing agent D to the intermediate product C in S6 is n(H+):n(Ti)=0.01-10, the reaction temperature of the membrane reactor D4 is 5-100°C, and the reaction time is 0.5-24 h.

[0031] In some embodiments, the membrane reactor D4 is a dynamic rotating membrane reactor, the rotation speed of the filter element of the membrane reactor D4 is 0-1000 r / min, and the transmembrane pressure difference of the membrane reactor D4 is 0-500 kPa.

[0032] In some embodiments, the filter precision of the membrane separator D2 is 50-1000 nm.

[0033] In some embodiments, the filter precision of the membrane reactor D4 is 2-500 nm.

[0034] In some embodiments, the filter precision of the membrane separator D5 is 2-200 nm.

[0035] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts a full membrane process of membrane dispersion, membrane separation, membrane concentration, membrane washing, membrane grading and membrane recovery to realize the continuous preparation of nano-scale titanium oxide particle sol; adopts membrane reactor D1 (dynamic rotating membrane reactor) to add reactants, so that the reactants are dispersed more evenly in the system, and the wide distribution of product particle size caused by local excessively high or low concentration is suppressed; adopts membrane separator D2 to separate, concentrate and wash the intermediate product, and reduce the alcohol content of the intermediate product; adopts membrane separator D3 (molecular sieve membrane) to realize efficient separation of alcohol and water, and the recycling rate of alcohol reaches more than 95%; adopts membrane reactor D4 to prepare target product, and then combines membrane separator D5 to perform online particle grading of target product; reactants in the entire reaction system are hydrolyzed and polymerized under relatively low concentration conditions, which is conducive to controlling the uniformity of distribution of product particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the preparation structure of the nano-sized titanium oxide particle sol shown in the present invention;

[0037] Figure 2 Schematic diagram of the structure of the membrane reactor D1 shown in the present invention;

[0038] Figure 3 A schematic diagram of a process for preparing nano-sized titanium oxide particle sol using the apparatus of the present invention;

[0039] Figure 4 This is a schematic diagram of the classification effect of the membrane reactor D4 shown in the present invention. DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent replacements or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0041] Example 1

[0042] like Figures 1-2 As shown, a device for preparing nano-scale titanium oxide particle sol includes a membrane reactor D1, a membrane separator D2, a membrane separator D3, a membrane reactor D4 and a membrane separator D5 connected in sequence; the concentrated liquid side of the membrane reactor D1 is connected to the concentrated liquid side of the membrane separator D2, and the clear liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane separator D3; the concentrated liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane reactor D4, the clear liquid side of the membrane reactor D4 is connected to the concentrated liquid side of the membrane separator D5, and the clear liquid side of the membrane separator D5 is connected to the concentrated liquid side of the membrane reactor D4.

[0043] The concentrated liquid side of the membrane separator D2 is connected with a pure water source, which can be used to wash the intermediate product C in the membrane separator D2, and reduce the alcohol content of the intermediate product C. The clear liquid side of the membrane separator D2 is connected with a reverse osmosis system, and the washing wastewater of the membrane separator D2 enters the reverse osmosis system for concentration. The concentrated liquid after concentration enters the membrane separator D3 for separation again, so as to realize efficient separation of the alcohol solvent A and water, reuse the alcohol solvent A, and the recovery rate is as high as 95% or more.

[0044] The membrane reactor D1 is a dynamic rotary membrane reactor, the filtering element of the membrane reactor D1 is a disc type membrane, and the filtering precision of the membrane is 2-2000nm. The filtering element material is one or a combination of alumina, zirconia, titania, silica, yttria, ceria, lanthana and silicon carbide.

[0045] The membrane reactor D1 comprises a shell 1, a hollow rotating shaft 2 penetrating through the bottom of the shell, a driver 3 connected below the hollow rotating shaft 2, and a plurality of filtering elements 5 and a spacer ring 6 installed on the upper part of the hollow rotating shaft 2 inside the shell 1. The upper part of the shell 1 is further provided with a first liquid inlet 10 and a liquid outlet 11, and the lower part of the hollow rotating shaft 2 is provided with a second liquid inlet 4.

[0046] The membrane reactor D1 further comprises a stirring device 9 located above the hollow rotating shaft 2, a rotating shaft 8 arranged above the membrane reactor D1 is controlled by a motor 7, and the stirring device 9 is connected below the rotating shaft 8. When the membrane reactor D1 works, the stirring device 9 accelerates the stirring and dispersion, which can further strengthen the dispersion uniformity of the reactants.

[0047] In this embodiment, a plurality of filtering elements 5 and spacer rings 6 are arranged in the membrane reactor D1, and the filtering elements 5 and the spacer rings 6 are arranged in sequence and at intervals. The adjacent two spacer rings 6 can tightly seal the filtering elements 5 on the hollow rotating shaft 2. Compared with the prior art, the filtering elements 5 are used as distributors in the present application, and are no longer used for material separation.

[0048] The membrane separator D3 is a molecular sieve membrane separator, and the filtering element of the membrane separator D3 is any one of a disc type membrane, a tube type membrane or a hollow fiber membrane.

[0049] The filtering element material of the membrane separator D3 is one or more of A type, CHA type or MFI type.

[0050] The filtering precision of the membrane separator D2 is 50-1000nm. The filtering precision of the membrane reactor D4 is 2-500nm. The filtering precision of the membrane separator D5 is 2-200nm.

[0051] In the present application, the membrane separator D2 and the membrane reactor D4 both adopt dynamic rotating membranes. The membrane separator D5 can adopt dynamic rotating membranes or tubular membranes, hollow fiber membranes or roll-type membranes. Unlike the membrane reactor D1, the filtering elements in the membrane separator D2, the membrane reactor D4 and the membrane separator D5 are used for filtering separation and concentration, not as distributors, and their materials can be the same as those of the membrane reactor D1.

[0052] The clear liquid in the present application refers to the side of the filtering element through which the liquid passes, and the concentrated liquid refers to the side of the filtering element through which the liquid does not pass, i.e. the outside of the filtering element.

[0053] Example 2

[0054] As shown in Figures 1-4 The present application provides a method for preparing a nano-sized titanium oxide particle sol, comprising the following steps:

[0055] S1: uniformly mixing an alcohol solvent A and a titanium precursor B, controlling the concentration of the titanium precursor B, and obtaining a reactant AB;

[0056] S2: uniformly mixing the alcohol solvent A and deionized water, controlling the concentration of the deionized water, and obtaining a reactant AH;

[0057] S3: adding the reactant AB and the reactant AH into a membrane reactor D1 respectively for reaction, and controlling the feeding concentration of the reactant AH, to obtain an intermediate product C;

[0058] S4: passing the intermediate product C into a membrane separator D2, separating and concentrating the solid-phase intermediate product C and the liquid-phase material, and then passing the liquid-phase material into a membrane separator D3 for post-treatment to obtain the alcohol solvent A for reuse, and discharging the separated water into a wastewater treatment system;

[0059] S5: adding deionized water into the membrane separator D2 multiple times to wash the solid-phase intermediate product C multiple times, and then passing the intermediate product C into a membrane reactor D4 after washing;

[0060] S6: adding a peptizing agent D into the membrane reactor D4 for reaction, and controlling the concentration of the peptizing agent D, to obtain a low-concentration target product E, wherein the membrane reactor D4 is a dynamic rotating membrane reactor, the rotating speed of the filtering element of the membrane reactor D4 is 0-1000 r / min, and the transmembrane pressure difference of the membrane reactor D4 is 0-500 kPa;

[0061] S7: concentrating the target product by a membrane separator D5 to obtain a high-concentration nano-sized titanium oxide particle sol.

[0062] The alcohol solvent A is one or more of ethanol, n-propanol, isopropanol, n-butanol, and the titanium precursor B is one or more of tetraethyl titanate, n-propyl titanate, tetraisopropyl titanate, and n-butyl titanate.

[0063] The concentration C (Ti) of the titanium precursor B is 0.001-0.5 mol / L, and the concentration C (H2O) of the deionized water is 0.001-55.5 mol / L.

[0064] The gel solvent D is one or more of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, acetic acid, and perchloric acid.

[0065] The reactant AH enters the membrane reactor D1 through the second inlet 4, the reactant AB enters the membrane reactor D1 through the first inlet 10, and the reactant AH is uniformly dispersed in the membrane reactor D1 through the membrane layer micropores of the filter element 5, so as to avoid local high concentration. The reactant AH and the reactant AB contact and hydrolyze on the outer surface of the filter element 5.

[0066] The molar ratio of the reactant AH to the reactant AB in S1 is n (Ti) : n (H2O) = 0.01-1, the reaction temperature of the membrane reactor D1 is 5-80℃, the reaction time is 5-120 min, the transmembrane pressure difference of the membrane reactor D1 is 0-300 kPa, and the rotation speed of the filter element of the membrane reactor D1 is 0-1000 r / min.

[0067] The membrane reactor D1 utilizes the microporous membrane layer of the filter element, and the reactant AH is uniformly dispersed in the membrane reactor D1 by controlling the membrane layer pore size and the feeding conditions, so as to avoid local high concentration.

[0068] In S6, the intermediate product C enters the membrane reactor D4, the gel solvent D and the intermediate product C are added and reacted, the molar ratio of the two is n (H+) : n (Ti) = 0.01-10, the reaction temperature of the membrane reactor D4 is 5-100℃, the reaction time is 0.5-24 h, the target product E is obtained, the particle size of the target product E is smaller than the pore size of the filter element in the membrane reactor D4, and the target product E transmits through the filter element and enters the membrane separator D5 for further concentration, so as to obtain a nano-sized titanium oxide particle sol product.

[0069] The application adopts the whole membrane process of membrane dispersion, membrane separation, membrane concentration, membrane washing, membrane grading and membrane recovery to realize the continuous preparation of nanometer titanium oxide particle sol; the membrane reactor D1 (dynamic rotating membrane reactor) is used to add reactants to make the reactants more uniformly dispersed in the system and inhibit the product particle size distribution from being too wide due to too high or too low local concentration; the membrane separator D2 is used to separate, concentrate and wash the intermediate product to reduce the alcohol content of the intermediate product; the membrane separator D3 (molecular sieve membrane) is used to realize the efficient separation of alcohol and water, and the alcohol reuse rate is more than 95%; the membrane reactor D4 is used to prepare the target product, and the membrane separator D5 is used to grade the target product on line; the reactants in the whole reaction system are hydrolyzed and polymerized under low concentration conditions, which is conducive to controlling the uniformity of the product particle size distribution.

[0070] The target product is allowed to pass through the membrane separator D4 into the membrane separator D5 for further concentration, and the large particle sol is intercepted, and the particle size of the target product is shown in Table 1 and Figure 4 As can be seen, the sol particles below 100 nm are allowed to pass through the membrane separator D5 for further concentration, and the nanometer titanium oxide particle sol is finally obtained. As can be seen from Table 2, the permeate of the membrane separator D5 does not meet the minimum photon number required for testing, indicating that the nanometer sol particles are intercepted outside the filter element, further indicating that the preparation of nanometer titanium oxide particle sol can be realized by the method.

[0071] The filter element of the membrane separator D5 in this embodiment can be selected from different materials and tested.

[0072] Table 1 Particle size test of the permeate of the membrane separator D4 and the membrane separator D5

[0073]

[0074] Table 2 Grading and screening of sols with different particle sizes by the membrane separator D4

[0075]

[0076] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the application, and are not used to limit the protection scope of the application. Equivalent embodiments or changes made without departing from the spirit of the application should be included in the protection scope of the application.

[0077] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for preparing nano-sized titanium oxide particle sol, characterized in that: It includes a membrane reactor D1, a membrane separator D2, a membrane separator D3, a membrane reactor D4 and a membrane separator D5 which are connected in sequence; the concentrated liquid side of the membrane reactor D1 is connected to the concentrated liquid side of the membrane separator D2, and the clear liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane separator D3; the concentrated liquid side of the membrane separator D2 is connected to the concentrated liquid side of the membrane reactor D4, the clear liquid side of the membrane reactor D4 is connected to the concentrated liquid side of the membrane separator D5, and the clear liquid side of the membrane separator D5 is connected to the concentrated liquid side of the membrane reactor D4.

2. The device for preparing nano-sized titanium oxide particle sol according to claim 1, characterized in that: The concentrate side of the membrane separator D2 is connected to a pure water source.

3. The device for preparing nano-sized titanium oxide particle sol according to claim 2, characterized in that: The clear liquid side of the membrane separator D2 is connected to a reverse osmosis system.

4. The device for preparing nano-sized titanium oxide particle sol according to claim 1, characterized in that: The membrane reactor D1 is a dynamic rotating membrane reactor. The filter element of the membrane reactor D1 is a disc-type membrane, and the filtration accuracy of the membrane is 2-2000 nm.

5. The device for preparing nano-sized titanium oxide particle sol according to claim 4, characterized in that: The membrane reactor D1 comprises a shell (1), a hollow rotating shaft (2) passing through the bottom of the shell, a driver (3) connected to the bottom of the hollow rotating shaft (2), the upper part of the hollow rotating shaft (2) is located inside the shell (1) and is installed with a plurality of filter elements (5) and spacers (6), the upper part of the shell (1) is also provided with a first liquid inlet (10) and a liquid outlet (11), and the lower part of the hollow rotating shaft (2) is provided with a second liquid inlet (4).

6. The device for preparing nano-sized titanium oxide particle sol according to claim 5, characterized in that: The membrane reactor D1 further includes a stirring device (9) located above the hollow rotating shaft (2).

7. The device for preparing nano-sized titanium oxide particle sol according to claim 5, characterized in that: The filter element (5) and the spacer (6) are arranged in sequence and spaced apart, and the filter element (5) is used as a distributor.

8. The device for preparing nano-sized titanium oxide particle sol according to claim 1, characterized in that: The membrane separator D3 is a molecular sieve membrane separator, and the filter element of the membrane separator D3 is any one of a disc membrane, a tubular membrane or a hollow fiber membrane.

9. The device for preparing nano-sized titanium oxide particle sol according to claim 8, characterized in that: The filter element material of the membrane separator D3 is one or more of type A, type CHA or type MFI.

10. A method for preparing nano-sized titanium oxide particle sol using the apparatus according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: uniformly mixing the alcohol solvent A and the titanium precursor B, controlling the concentration of the titanium precursor B, to obtain a reactant AB; S2: uniformly mixing the alcohol solvent A and deionized water, controlling the concentration of the deionized water, to obtain reactant AH; S3: Add reactant AB and reactant AH into membrane reactor D1 respectively for reaction, and control the feed concentration of reactant AH to obtain intermediate product C; S4: The intermediate product C is passed into the membrane separator D2 to separate and concentrate the solid intermediate product C and the liquid phase material. The liquid phase material is passed into the membrane separator D3 for post-processing to obtain the alcohol solvent A for reuse; S5: Add deionized water to the membrane separator D2 multiple times to wash the solid intermediate product C multiple times, and then pass the intermediate product C into the membrane reactor D4; S6: adding a peptizing agent D to the membrane reactor D4 to react, controlling the concentration of the peptizing agent D, and obtaining a low-concentration target product E; S7: The membrane separator D5 concentrates the target product to obtain a high-concentration nano-sized titanium oxide particle sol.

11. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The alcohol solvent A is one or more of ethanol, n-propanol, isopropanol, and n-butanol, and the titanium precursor B is one or more of tetraethyl titanate, n-propyl titanate, tetraisopropyl titanate, and n-butyl titanate.

12. The method for preparing nano-sized titanium oxide particle sol according to claim 11, characterized in that: The concentration of the titanium precursor B is C (Ti) = 0.001-0.5 mol / L, and the concentration of the deionized water is C (H2O) = 0.001-55.5 mol / L.

13. The method for preparing nano-sized titanium oxide particle sol according to claim 12, characterized in that: The peptizing agent D is one or more of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, acetic acid, and perchloric acid.

14. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The reactant AH enters the membrane reactor D1 through the second liquid inlet (4), and the reactant AB enters the membrane reactor D1 through the first liquid inlet (10). The reactant AH is distributed through the micropores of the membrane layer of the filter element (5) and can be evenly dispersed in the membrane reactor D1 to avoid excessive local concentration. The reactant AH and the reactant AB contact on the outer surface of the filter element (5) and undergo a hydrolysis reaction.

15. The method for preparing nano-sized titanium oxide particle sol according to claim 14, characterized in that: The molar ratio of reactant AH to reactant AB in S1 is n(Ti):n(H2O)=0.01~1, the reaction temperature of the membrane reactor D1 is 5~80°C, the reaction time is 5~120min, the transmembrane pressure difference of the membrane reactor D1 is 0-300kPa, and the filter element rotation speed of the membrane reactor D1 is 0~1000r / min.

16. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The molar ratio of the peptizing agent D and the intermediate product C in the S6 is n(H+):n(Ti)=0.01-10, the reaction temperature of the membrane reactor D4 is 5-100°C, and the reaction time is 0.5-24h.

17. The method for preparing nano-sized titanium oxide particle sol according to claim 16, characterized in that: The membrane reactor D4 is a dynamic rotating membrane reactor. The filter element rotation speed of the membrane reactor D4 is 0-1000 r / min, and the transmembrane pressure difference of the membrane reactor D4 is 0-500 kPa.

18. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The filtration accuracy of the membrane separator D2 is 50-1000 nm.

19. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The filtration accuracy of the membrane reactor D4 is 2-500 nm.

20. The method for preparing nano-sized titanium oxide particle sol according to claim 10, characterized in that: The filtration accuracy of the membrane separator D5 is 2-200 nm.

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