阅读说明：本技术 一种高通量改性氧化钛复合超滤膜及其应用 (High-flux modified titanium oxide composite ultrafiltration membrane and application thereof ) 是由 陈云强 洪昱斌 方富林 蓝伟光 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种高通量改性氧化钛复合超滤膜及其应用,本发明选择磺基丙氨酸来对膜层表面进行改性,磺基丙氨酸上的羧基会与陶瓷膜上的硅烷偶联剂发生反应,提高膜层的亲水性,使氧化钛膜层的水表面接触角从38°提高到6-10°,这是由于磺基丙氨酸亲水基团包括了酰磺基和氨基两部分,磺基丙氨酸的亲水基团部分能和溶剂形成多重氢键,使膜层表面具有很强的亲水性,提升了抗污染性能和水通量。(The invention discloses a high-flux modified titanium oxide composite ultrafiltration membrane and application thereof, wherein cysteic acid is selected to modify the surface of a membrane layer, carboxyl on the cysteic acid reacts with a silane coupling agent on a ceramic membrane to improve the hydrophilicity of the membrane layer, so that the water surface contact angle of the titanium oxide membrane layer is improved from 38 degrees to 6-10 degrees, because the cysteic acid hydrophilic group comprises an acyl sulfo group and an amino group, and the hydrophilic group part of the cysteic acid can form multiple hydrogen bonds with a solvent, so that the surface of the membrane layer has strong hydrophilicity, and the anti-pollution performance and the water flux are improved.)

1. A high-flux modified titanium oxide composite ultrafiltration membrane is characterized in that: the titanium oxide separation membrane is grafted with cysteic acid through a silane coupling agent so that the water contact angle of the surface of the titanium oxide separation membrane layer is 6-10 degrees.

2. The high-throughput modified titanium oxide composite ultrafiltration membrane of claim 1, wherein: the silane coupling agent is 3-aminopropyl triethoxysilane.

3. The preparation method of the high-flux modified titanium oxide composite ultrafiltration membrane of claim 1 or 2, which is characterized in that: the method comprises the following steps:

(1) preparing titanium oxide sol by a sol-gel method;

(2) adding a plasticizer, a binder and a defoaming agent into the titanium oxide sol to prepare a coating solution;

(3) dip-coating the coating solution on a porous ceramic membrane support, and drying and sintering to obtain a titanium oxide separation membrane layer;

(4) activating the titanium oxide separation film layer by alkali, soaking the titanium oxide separation film layer in a silane coupling agent solution, reacting at room temperature, fully washing, and drying to obtain a titanium oxide separation film layer grafted with a silane coupling agent;

(5) and (3) soaking the titanium oxide separation membrane layer grafted with the silane coupling agent in a cysteic acid solution, and reacting for 3-5h at 78-82 ℃ to obtain the titanium oxide separation membrane.

4. The method of claim 3, wherein: the step (1) is as follows: adding a dispersing agent into the organic titanium solution, adding acid for dispergation, wherein the pH value of the dispergated sol is 2-5, adding the dispersing agent, and uniformly mixing to prepare the titanium oxide sol.

5. The method of claim 4, wherein: the solute of the organic titanium solution is n-butyl titanate or isopropyl titanate.

6. The method of claim 3, wherein: the concentration of the silane coupling agent solution is 1.9-2.1mmol/L, and the concentration of the sulfoalanine solution is 1-5 mol/L.

7. The method of claim 3, wherein: the dispersing agent is polyethylene glycol or glycerol.

8. The method of claim 3, wherein: the plasticizer is polyvinyl alcohol, the binder is a cellulose compound, and the defoaming agent is an organic silicon defoaming agent.

9. The method of claim 3, wherein: in the step (3), the drying and calcining specifically include: heating to 80-120 ℃ at room temperature at the speed of 1-3 ℃/min, then preserving heat and drying for 2-5h, heating to 500-.

10. The application of the high-flux modified titanium oxide composite ultrafiltration membrane in the treatment of oily wastewater in claim 1 or 2.

Technical Field

The invention belongs to the technical field of membrane separation, and particularly relates to a high-flux modified titanium oxide composite ultrafiltration membrane and application thereof.

Background

With the rapid development of social economy, people generate a large amount of oily wastewater in production and life. Research and investigation show that oily wastewater is generated in the industrial fields of chemical industry, food, petroleum, metallurgy, medicine and the like, a large amount of oily wastewater is directly discharged into natural water every year on the earth, the oily wastewater can cause great harm to the environment, agricultural crops are reduced in yield or die when the oily wastewater is used for irrigating farmlands, and livestock can cause esophagus infection and disease and endanger human health through a food chain when drinking the oily wastewater. Therefore, how to treat oily wastewater efficiently becomes a focus of attention of researchers.

The traditional treatment process of oily wastewater mainly comprises centrifugal separation, gravity separation, chemical treatment, particle filler filtration and the like. The oily wastewater after traditional filtration can basically meet the discharge requirement, but the oil content and the particle size of the filtered water can hardly reach the first-level discharge standard. In recent years, advanced treatment of oil-containing wastewater by membrane separation has become a research hotspot. The membrane separation method can not only rapidly treat and solve the problem of water pollution, but also can not bring secondary pollution, can realize cyclic utilization, saves resources and protects the environment. In the early stage, an organic ultrafiltration membrane is adopted to treat oily wastewater, and suspended oil drops are intercepted by membrane pores, so that an oil-water separation effect is achieved. But the membrane itself is limited by temperature and cannot be operated at higher temperatures and therefore has a short lifetime. With the technology changing day by day, inorganic ceramic membranes began to move to the historical stage. The excellent characteristics of the ceramic membrane make the ceramic membrane show very good prospects in the industry for treating oily wastewater. But the oily wastewater is easy to corrode the ceramic membrane and easily blocks the membrane pores, thereby reducing the service life. Therefore, the modification of the ceramic membrane is very important, wherein the improvement of the hydrophilicity of the ceramic membrane is the key point for solving the problem.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a high-flux modified titanium oxide composite ultrafiltration membrane.

The invention also aims to provide a preparation method of the high-throughput modified titanium oxide composite ultrafiltration membrane.

The invention further aims to provide application of the high-flux modified titanium oxide composite ultrafiltration membrane.

The technical scheme of the invention is as follows:

a high-flux modified titanium oxide composite ultrafiltration membrane comprises a porous ceramic membrane support and a titanium oxide separation membrane layer, wherein the titanium oxide separation membrane is grafted with cysteic acid through a silane coupling agent so that the water contact angle of the surface of the titanium oxide separation membrane layer is 6-10 degrees.

In a preferred embodiment of the present invention, the silane coupling agent is 3-aminopropyltriethoxysilane.

The other technical scheme of the invention is as follows:

the preparation method of the high-flux modified titanium oxide composite ultrafiltration membrane is characterized by comprising the following steps of: the method comprises the following steps:

(1) preparing titanium oxide sol by a sol-gel method;

(2) adding a plasticizer, a binder and a defoaming agent into the titanium oxide sol to prepare a coating solution;

(3) dip-coating the coating solution on a porous ceramic membrane support, and drying and sintering to obtain a titanium oxide separation membrane layer;

(4) activating the titanium oxide separation film layer by alkali, soaking the titanium oxide separation film layer in a silane coupling agent solution, reacting at room temperature, fully washing, and drying to obtain a titanium oxide separation film layer grafted with a silane coupling agent;

(5) and (3) soaking the titanium oxide separation membrane layer grafted with the silane coupling agent in a cysteic acid solution, and reacting for 3-5h at 78-82 ℃ to obtain the titanium oxide separation membrane.

In a preferred embodiment of the present invention, the step (1) is: adding a dispersing agent into the organic titanium solution, adding acid for dispergation, wherein the pH value of the dispergated sol is 2-5, adding the dispersing agent, and uniformly mixing to prepare the titanium oxide sol.

Further preferably, the solute of the organic titanium solution is n-butyl titanate or isopropyl titanate.

In a preferred embodiment of the present invention, the concentration of the silane coupling agent solution is 1.9 to 2.1mmol/L and the concentration of the cysteic acid solution is 1 to 5 mol/L.

In a preferred embodiment of the invention, the dispersant is polyethylene glycol or glycerol.

In a preferred embodiment of the present invention, the plasticizer is polyvinyl alcohol, the binder is a cellulose-based compound, and the defoaming agent is a silicone defoaming agent.

In a preferred embodiment of the present invention, in the step (3), the drying and calcining are specifically: heating to 80-120 ℃ at room temperature at the speed of 1-3 ℃/min, then preserving heat and drying for 2-5h, heating to 500-.

The invention adopts another technical scheme as follows:

the high-flux modified titanium oxide composite ultrafiltration membrane is applied to the treatment of oily wastewater.

The invention has the beneficial effects that: according to the invention, the surface of the film layer is modified by selecting the cysteic acid, carboxyl on the cysteic acid reacts with a silane coupling agent on the ceramic film, the hydrophilicity of the film layer is improved, the contact angle of the water surface of the titanium oxide film layer is improved from 38 degrees to 6-10 degrees, and the hydrophilic group of the cysteic acid comprises two parts of acyl sulfo group and amino group, and the hydrophilic group part of the cysteic acid and a solvent can form multiple hydrogen bonds, so that the surface of the film layer has strong hydrophilicity, and the anti-pollution performance and the water flux are improved.

Detailed Description

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

Comparative example 1

(1) Preparing titanium oxide sol by adopting a sol-gel method: adding 0.5% of dispersant polyethylene glycol into 0.5mol/L of n-butyl titanate solution, in a sol-gel reaction, adding acid to carry out dispergation, wherein the molar ratio of n-butyl titanate to water is 1: 10, and the pH value of the dispergated sol is 4 to obtain titanium dioxide sol, adding 1% of dispersant polyethylene glycol, and uniformly mixing to prepare the well-dispersed titanium oxide sol.

(2) Adding 2% of polyvinyl alcohol and 5% of hydroxyethyl cellulose into the prepared titanium oxide sol with good dispersion, fully and uniformly mixing, and then adding 0.01% of defoaming agent to prepare a coating liquid with uniform dispersion.

(3) And (3) coating the coating liquid on a porous ceramic membrane support with the average pore diameter of 0.1 mu m by adopting a dip-coating mode, heating to 120 ℃ at room temperature at the speed of 3 ℃/min, then preserving heat, drying for 5h, heating to 600 ℃ at the speed of 3 ℃/min, preserving heat, sintering for 3h, and then naturally cooling to obtain a contrast membrane (the water surface contact angle of the titanium oxide membrane layer is 38 degrees).

The rejection rate of the oily wastewater with 15g/L oil content filtered by the comparative membrane prepared by the comparative example is about 95, and the flux of the oily wastewater is 300LHM under the conditions of 0.1MPa and 25 ℃.

Comparative example 2

(1) Preparing titanium oxide sol by adopting a sol-gel method: adding 0.5% of dispersant polyethylene glycol into 0.8mol/L of n-butyl titanate solution, in a sol-gel reaction, adding acid to carry out dispergation, wherein the molar ratio of n-butyl titanate to water is 1: 50, and the pH value of the dispergated sol is 4 to obtain titanium dioxide sol, adding 1% of dispersant polyethylene glycol, and uniformly mixing to prepare the well-dispersed titanium oxide sol.

(2) And adding 3% of polyvinyl alcohol and 5% of hydroxyethyl cellulose into the prepared titanium oxide sol with good dispersion, fully and uniformly mixing, and then adding 0.01% of defoaming agent to prepare a coating liquid with uniform dispersion.

(3) Coating the coating liquid on a porous ceramic membrane support with the average pore diameter of 0.1 mu m by adopting a dip-coating mode, heating to 120 ℃ at room temperature at the speed of 1 ℃/min, then preserving heat, drying for 5h, heating to 600 ℃ at the speed of 5 ℃/min, preserving heat, sintering for 5h, and then naturally cooling.

(4) And (3) soaking the material obtained in the step (3) in 1mol/L sodium hydroxide solution for 5h, drying at 100 ℃ for 24h, cooling, soaking in 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting at room temperature for 12h, sequentially washing with ethanol and deionized water for several times, drying in a drying oven at a set temperature of 150 ℃ for 12h, and cooling in the oven to obtain the grafted ceramic membrane.

(5) And (3) soaking the grafted ceramic membrane in a sulfoalanine aqueous solution with the concentration of 0.5mol/L for 10min, taking out the membrane tube, and reacting for 3h in an oven at 80 ℃ to prepare a contrast membrane (the water surface contact angle of the titanium oxide membrane layer is 22 degrees).

Under the conditions of 0.1MPa and 25 ℃, the rejection rate of the oily wastewater with 15g/L oil content filtered by the comparative membrane prepared by the comparative example is 96%, and the flux of the oily wastewater is 420 LHM.

Example 1

(1) - (3) same as in comparative example 2.

(4) And (3) soaking the material obtained in the step (3) in 1mol/L sodium hydroxide solution for 5h, drying at 100 ℃ for 24h, cooling, soaking in 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting at room temperature for 12h, sequentially washing with ethanol and deionized water for several times, drying in a drying oven at a set temperature of 150 ℃ for 12h, and cooling in the oven to obtain the grafted ceramic membrane.

(5) And (3) soaking the grafted ceramic membrane in a 1mol/L aqueous solution of cysteic acid for 10min, taking out the membrane tube, and reacting for 3h at 80 ℃ in an oven to obtain the high-flux modified titanium oxide composite ultrafiltration membrane (the water surface contact angle of the titanium oxide membrane layer is 10 degrees).

Under the conditions of 0.1MPa and 25 ℃, the high-flux modified titanium oxide composite ultrafiltration membrane prepared by the comparative example filters the oily wastewater with the oil content of 15g/L, the retention rate of 99 percent and the flux of 530 LHM.

Example 2

(1) Preparing titanium oxide sol by adopting a sol-gel method: adding 0.5% of dispersant polyethylene glycol into 1mol/L of n-butyl titanate solution, in a sol-gel reaction, adding acid to carry out dispergation, wherein the molar ratio of n-butyl titanate to water is 1: 100, and the pH of the dispergated sol is 5 to obtain titanium dioxide sol, adding 1% of dispersant polyethylene glycol, and uniformly mixing to prepare the well-dispersed titanium oxide sol.

(2) And adding 3% of polyvinyl alcohol and 2% of hydroxyethyl cellulose into the prepared titanium oxide sol with good dispersion, fully and uniformly mixing, and then adding 0.1% of defoaming agent to prepare a coating liquid with uniform dispersion.

(3) Coating the coating liquid on a porous ceramic membrane support with the average pore diameter of 0.1 mu m by adopting a dip-coating mode, heating to 120 ℃ at room temperature at the speed of 1 ℃/min, then preserving heat, drying for 5h, heating to 700 ℃ at the speed of 5 ℃/min, preserving heat, sintering for 5h, and then naturally cooling.

(4) And (3) soaking the material obtained in the step (3) in 1mol/L sodium hydroxide solution for 5h, drying at 100 ℃ for 24h, cooling, soaking in 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting at room temperature for 12h, sequentially washing with ethanol and deionized water for several times, drying in a drying oven at a set temperature of 150 ℃ for 12h, and cooling in the oven to obtain the grafted ceramic membrane.

(5) And (3) soaking the grafted ceramic membrane in a 3mol/L sulfoalanine aqueous solution for 10min, taking out the membrane tube, and reacting for 5h in an oven at 80 ℃ to prepare the high-flux modified titanium oxide composite ultrafiltration membrane (the water surface contact angle of the titanium oxide membrane layer is 7 degrees).

Under the conditions of 0.1MPa and 25 ℃, the high-flux modified titanium oxide composite ultrafiltration membrane prepared by the embodiment filters 98 percent of oily wastewater with the oil content of 15g/L and the flux of the oily wastewater is 550 LHM.

Example 3

(1) - (4) same as in example 2.

(5) And (3) soaking the grafted ceramic membrane in a 5mol/L aqueous solution of cysteic acid for 10min, taking out the membrane tube, and reacting for 5h at 80 ℃ in an oven to obtain the high-flux modified titanium oxide composite ultrafiltration membrane (the water surface contact angle of the titanium oxide membrane layer is 6 degrees).

Under the conditions of 0.1MPa and 25 ℃, the high-flux modified titanium oxide composite ultrafiltration membrane prepared by the embodiment filters 98 percent of oily wastewater with the oil content of 15g/L and has the flux of 570LHM of the oily wastewater.

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims.