阅读说明：本技术 一种高通量陶瓷超滤膜的制备方法 (Preparation method of high-flux ceramic ultrafiltration membrane ) 是由 陈云强 洪昱斌 方富林 蓝伟光 于 2019-09-12 设计创作，主要内容包括：本发明公开了一种高通量陶瓷超滤膜的制备方法。本发明将溶胶-凝胶方法和水热方法有机结合在一起,利用嵌段共聚物作为模板结合,将其添加到溶胶中直接制成涂膜液,加入适量的添加剂,经过干燥、煅烧制成制备孔径分布窄、高通量的陶瓷超滤膜。与传统的固态粒子烧结法和溶胶-凝胶法相比,本发明解决了粒子易团聚和需要多次涂膜的困难,且对支撑体的要求也不苛刻,方法简单,节省能源易于实现工业化,加入嵌段共聚物能够提高膜层的孔隙率,纯水通量从100LHM提高到145-160LHM。(The invention discloses a preparation method of a high-flux ceramic ultrafiltration membrane. The invention organically combines a sol-gel method and a hydrothermal method, utilizes block copolymer as a template for combination, adds the block copolymer into sol to directly prepare coating liquid, adds a proper amount of additive, and prepares the ceramic ultrafiltration membrane with narrow pore size distribution and high flux through drying and calcining. Compared with the traditional solid particle sintering method and the sol-gel method, the invention solves the problems of easy agglomeration of particles and the need of coating for multiple times, has no strict requirement on a support body, has simple method, saves energy and is easy to realize industrialization, the porosity of a film layer can be improved by adding the block copolymer, and the pure water flux is improved from 100LHM to 145-160 LHM.)

1. A preparation method of a high-flux ceramic ultrafiltration membrane is characterized by comprising the following steps: the method comprises the following steps:

(1) dripping 4-6 wt% water alcohol solution into 0.2-0.8mol/L organic titanium salt solution at 75-85 deg.C at 0.8-1.5 drops/s, adding acid solution for dispergation, and ultrasonically mixing to obtain titanium oxide sol with pH of 3-5, wherein the molar ratio of organic titanium salt to water is 1: 10-30;

(2) putting the titanium oxide sol obtained in the step (1) into a hydrothermal reaction kettle, reacting for 5-10h at the temperature of 150-200 ℃, and cooling at room temperature to prepare a titanium oxide nano solution;

(3) adding polyoxyethylene-polyoxypropylene-polyoxyethylene with the molecular weight of 5500-6000g/mol into the titanium oxide nano solution, adding polyethylene glycol with the weight-average molecular weight of 350-500, cellulose compounds with the molecular weight of 6000-10000 and an organic silicon defoamer, and fully stirring to prepare a coating solution, wherein the molar ratio of the titanium oxide to the polyoxyethylene-polyoxypropylene-polyoxyethylene is 10-100: 1; the cellulose compound is hydroxymethyl cellulose or hydroxyethyl cellulose;

(4) coating the coating liquid on an alumina support body with the surface roughness less than 1um, heating to 80-120 ℃ at the speed of 0.8-1.2 ℃/min, preserving heat, drying for 2-5h, then heating to 400-600 ℃ at the speed of 0.8-1.2 ℃/min, preserving heat, calcining for 2-5h, and naturally cooling to obtain the high-flux ceramic ultrafiltration membrane.

2. The method of claim 1, wherein: the organic titanium salt is n-butyl titanate or isopropyl titanate.

3. The method of claim 1, wherein: the acid is hydrochloric acid or nitric acid.

4. The method of claim 1, wherein: the filling degree of the hydrothermal reaction kettle in the step (2) is 50-70%.

5. The method of claim 1, wherein: the final concentration of the polyethylene glycol in the coating liquid is 1-5 wt%.

6. The method of claim 1, wherein: the final concentration of the cellulose compound in the coating liquid is 0.5-5 wt%.

7. The method of claim 6, wherein: the final concentration of the organic silicon defoamer in the coating liquid is 0.01-0.1 wt%.

Technical Field

The invention belongs to the technical field of ultrafiltration membrane preparation, and particularly relates to a preparation method of a high-flux ceramic ultrafiltration membrane.

Background

Compared with organic films, inorganic films have good chemical stability, high mechanical strength, high temperature resistance, microbial corrosion resistance, long service life and the like, so the inorganic films become green and environment-friendly materials. The application field of inorganic membranes has been deep into various aspects of people's life and production, such as chemical industry, environmental protection, electronics, textiles, medicine, food, and the like. With the overall improvement of the modern industrial technology level, the requirement for the filtration precision of the ceramic membrane is higher and higher, and therefore, the development of more precise ceramic membrane preparation technology is required.

At present, the preparation methods of the ceramic ultrafiltration membrane mainly comprise a solid particle sintering method and a sol-gel method, and the nanoparticles prepared by the two methods have the problems of wider pore size distribution, lower porosity, low membrane flux, easy cracking of a membrane layer, harsh membrane layer preparation environment and the like, and are limited in practical industrial application.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a high-flux ceramic ultrafiltration membrane.

The technical scheme of the invention is as follows:

a preparation method of a high-flux ceramic ultrafiltration membrane comprises the following steps:

(1) dripping 4-6 wt% water alcohol solution into 0.2-0.8mol/L organic titanium salt solution at 75-85 deg.C at 0.8-1.5 drops/s, adding acid solution for dispergation, and ultrasonically mixing to obtain titanium oxide sol with pH of 3-5, wherein the molar ratio of organic titanium salt to water is 1: 10-30;

(2) putting the titanium oxide sol obtained in the step (1) into a hydrothermal reaction kettle, reacting for 5-10h at the temperature of 150-200 ℃, and cooling at room temperature to prepare a titanium oxide nano solution;

(3) adding polyoxyethylene-polyoxypropylene-polyoxyethylene with the molecular weight of 5500-6000g/mol into the titanium oxide nano solution, adding polyethylene glycol with the weight-average molecular weight of 350-500, cellulose compounds with the molecular weight of 6000-10000 and an organic silicon defoamer, and fully stirring to prepare a coating solution, wherein the molar ratio of the titanium oxide to the polyoxyethylene-polyoxypropylene-polyoxyethylene is 10-100: 1; the cellulose compound is hydroxymethyl cellulose or hydroxyethyl cellulose;

(4) coating the coating liquid on an alumina support body with the surface roughness less than 1um, heating to 80-120 ℃ at the speed of 0.8-1.2 ℃/min, preserving heat, drying for 2-5h, then heating to 400-600 ℃ at the speed of 0.8-1.2 ℃/min, and naturally cooling to obtain the high-flux ceramic ultrafiltration membrane.

In a preferred embodiment of the present invention, the organic titanium salt is n-butyl titanate or isopropyl titanate.

In a preferred embodiment of the invention, the acid is hydrochloric acid or nitric acid.

In a preferred embodiment of the present invention, the degree of filling of the hydrothermal reaction kettle in the step (2) is 50 to 70%.

In a preferred embodiment of the present invention, the final concentration of the polyethylene glycol in the coating solution is 1-5 wt%.

In a preferred embodiment of the present invention, the final concentration of the cellulose-based compound in the coating solution is 0.5-5 wt%.

In a preferred embodiment of the present invention, the final concentration of the silicone defoamer in the coating solution is 0.01 to 0.1 wt%.

The invention has the beneficial effects that: the invention organically combines a sol-gel method and a hydrothermal method, utilizes block copolymer as a template for combination, adds the block copolymer into sol to directly prepare coating liquid, adds a proper amount of additive, and prepares the ceramic ultrafiltration membrane with narrow pore size distribution and high flux through drying and calcining. Compared with the traditional solid particle sintering method and the sol-gel method, the invention solves the problems of easy agglomeration of particles and the need of coating for multiple times, has no strict requirement on a support body, has simple method, saves energy and is easy to realize industrialization, the porosity of a film layer can be improved by adding the block copolymer, and the pure water flux is improved from 100LHM to 145-160 LHM.

Detailed Description

The technical solution of the present invention is further illustrated and described by the following detailed description.

Comparative example 1

(1) Dripping 5 wt% water alcohol solution into 0.5mol/L n-butyl titanate solution at 80 ℃ at the speed of 1 drop/s, adding 1mol/L nitric acid or hydrochloric acid solution for dispergation, and ultrasonically mixing uniformly to obtain titanium oxide sol with pH of 4, wherein the molar ratio of n-butyl titanate to water is 1: 20;

(2) putting the titanium oxide sol obtained in the step (1) into a hydrothermal reaction kettle, reacting at 180 ℃ for 8h with the filling degree of 60%, and cooling at room temperature to obtain a titanium oxide nano solution;

(3) adding PEG400, hydroxymethyl cellulose with the molecular weight of 6000-10000 and an organic silicon defoaming agent byk028 (Germany Bikk) into the titanium oxide nano solution, and fully stirring to prepare a coating solution, wherein the final concentrations of the PEG400, the hydroxymethyl cellulose and the organic silicon defoaming agent in the coating solution are 3 wt%, 2 wt% and 0.05 wt% respectively;

(4) coating the film coating liquid on an alumina support body with the surface roughness less than 1um, heating to 100 ℃ at the speed of 1 ℃/min, preserving heat, drying for 3h, then heating to 450 ℃ at the speed of 1 ℃/mmin, preserving heat, calcining for 4h, and naturally cooling to obtain the titanium oxide ceramic ultrafiltration membrane, wherein the porosity is 35%, and the pure water flux is 100 LHM.